JP2008060558A - Insulating layer, electronic device, field effect transistor, and polyvinyl thiophenol - Google Patents

Abstract

Ｒ^aは直接結合又は任意の連結基を表わし、
Ａｒは置換されていても良い２価の芳香族基を表わし、
Ｒ^bは水素原子、フッ素原子又は一価の有機基を表わす。
【選択図】なしAn insulating layer capable of improving element characteristics when used in an electronic device is provided.
A polymer insulator containing a repeating unit represented by the following formula is contained in an insulating layer.

R ^a represents a direct bond or any linking group,
Ar represents an optionally substituted divalent aromatic group,
R ^b represents a hydrogen atom, a fluorine atom or a monovalent organic group.
[Selection figure] None

Description

  The present invention relates to an insulating layer, an electronic device and a field effect transistor including the insulating layer, and polyvinyl thiophenol, and more specifically, an insulating layer capable of improving electrical performance, an electronic device including the insulating layer, and a field effect. The present invention relates to a transistor and polyvinyl thiophenol that can be used therefor.

  For example, polyimide, benzocyclobutene, photoacryl, or the like is used as an organic insulating layer expected as a constituent member of an organic thin film transistor or the like. However, the actual situation is that the organic insulating layer does not exhibit element characteristics to the extent that it replaces the inorganic insulating layer (see Patent Document 1). Therefore, in order to realize an organic electronic device such as an organic thin film transistor, it is required to develop an organic insulating material that has excellent element characteristics and is advantageous for a printing process.

In recent years, an organic insulating layer in which polyvinylphenol and a crosslinking agent are combined has been found to meet the demand for this organic insulating material (see Non-Patent Document 1).
As another organic insulating material, Patent Document 2 uses a polymer obtained by polymerizing vinyl cinnamate.
US Pat. No. 6,232,157 JP 2005-303270 A Appl. Phys. Lett. 2002, 81 (2), 289

However, according to the study by the present inventors, the following problems have been found.
When an organic thin film transistor is produced using an organic insulating layer in which polyvinylphenol and a crosslinking agent described in Non-Patent Document 1 are combined, due to the hydroxyl group possessed by polyvinylphenol and the reactive group possessed by the crosslinking agent, An organic semiconductor (an organic compound exhibiting semiconductor characteristics) is easily doped. Therefore, in the organic thin film transistor using an organic insulating layer disclosed in Non-Patent Document 1, the mobility, on-off ratio (On / Off ratio), device characteristics such as threshold voltage V _t was found to be degraded .

On the other hand, in the technique described in Patent Document 2, polyvinyl cinnamate does not have a polar group such as a hydroxyl group, unlike polyvinyl phenol. Therefore, perform insolubilization in an organic solvent due to crosslinking reactions to polyvinyl cinnamate, when an insulating layer of an organic thin film transistor was effective in lowering the threshold voltage V _t due to doping of the semiconductor. However, even with the technique described in Patent Document 2, an organic thin film transistor using a semiconductor material that originally has a high threshold voltage V _t has no effect such as a decrease in the threshold voltage V _t .

Thus, when used in an organic thin film transistor, the mobility, the organic insulating layer that can improve device characteristics, such as On / Off ratio and threshold voltage V _t, although its development is desired, yet realized I did not. Similarly, in an electronic device other than an organic thin film transistor, the organic insulating layer as described above is not realized.
The present invention is to solve the problems of the conventional technique, and an insulating layer capable of improving element characteristics, an electronic device and a field effect transistor using the insulating layer, and polyvinyl thiol usable for the insulating layer. The object is to provide phenol.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have used at least polyvinyl aromatic thiol and / or polyvinyl aromatic thioether derivative for the insulating layer, and thus field effect transistors using the insulating layer, etc. in electronic devices, mobility, On / Off ratio, found that it is possible to improve the device characteristics such as threshold voltage V _t, and completed the present invention.

（式（Ａ）中、Ｒ^aは直接結合又は任意の連結基を表わし、Ａｒは置換されていても良い２価の芳香族基を表わし、Ｒ^bは水素原子、フッ素原子又は一価の有機基を表わす。） That is, the gist of the present invention resides in an insulating layer characterized in that it contains a polymer insulator containing at least a repeating unit represented by the following formula (A) (claim 1).

(In the formula (A), R ^a represents a direct bond or an arbitrary linking group, Ar represents an optionally substituted divalent aromatic group, and R ^b represents a hydrogen atom, a fluorine atom or a monovalent organic group. Represents a group.)

At this time, the Ra is preferably ^a direct bond (claim 2).
The Ar is preferably a hydrocarbon aromatic ring that may be substituted (claim 3).
Furthermore, it is preferable that R ^b is a hydrogen atom or a linear or branched hydrocarbon group.
In addition, it is preferable that the polymer insulator includes a repeating unit derived from at least vinylthiophenol and / or a vinylthiophenol derivative (Claim 5).
Furthermore, it is preferable that the polymer insulator includes a repeating unit derived from a crosslinkable vinyl monomer.
In addition, it is preferable that the polymer insulator includes a repeating unit derived from a heat-resistant vinyl monomer.
Further, the insulating layer of the present invention preferably has an electric conductivity of 1 × 10 ⁻¹² S / cm or less (claim 8).

  Another subject matter of the present invention lies in an electronic device comprising the insulating layer of the present invention (claim 9).

Still another subject matter of the present invention lies in a field effect transistor comprising the insulating layer of the present invention (claim 10).
At this time, the field effect transistor of the present invention preferably includes a semiconductor layer containing porphyrin, a source electrode, a drain electrode, and a gate electrode.

  Still another subject matter of the present invention lies in polyvinyl thiophenol characterized in that it contains at least a repeating unit derived from vinyl thiophenol and / or a vinyl thiophenol derivative and a repeating unit derived from a crosslinkable vinyl monomer. Item 12).

  Still another subject matter of the present invention lies in polyvinyl thiophenol characterized in that it contains at least a repeating unit derived from vinyl thiophenol and / or a vinyl thiophenol derivative and a repeating unit derived from a heat-resistant vinyl monomer. 13).

According to the insulating layer of the present invention, when used in an electronic device such as an organic field effect transistor, the element characteristics can be improved.
According to the electronic device of the present invention, element characteristics can be improved.
According to the field effect transistor of the present invention, it is possible to improve mobility, On / Off ratio and threshold voltage V _t.
According to the polyvinyl thiophenol of the present invention, the element characteristics of an electronic device such as an organic field effect transistor having an insulating layer using the polyvinyl thiophenol can be improved.

  Hereinafter, the present invention will be described with reference to examples and embodiments. However, the present invention is not limited to the following examples and embodiments, and may be arbitrarily changed without departing from the gist of the present invention. Can be implemented.

（式（Ａ）中、Ｒ^aは直接結合又は任意の連結基を表わし、Ａｒは置換されていても良い芳香族環を表わし、Ｒ^bは水素原子、フッ素原子又は一価の有機基を表わす。） [I. Insulation layer]
The insulating layer of the present invention contains at least a polymer insulator containing a repeating unit represented by the following formula (A).

(In the formula (A), R ^a represents a direct bond or an arbitrary linking group, Ar represents an optionally substituted aromatic ring, and R ^b represents a hydrogen atom, a fluorine atom or a monovalent organic group. .)

[I-1. Polymer insulator]
The polymer insulator according to the present invention has a repeating unit represented by the formula (A).
Here, in the formula (A), R ^a represents a direct bond or an arbitrary linking group. Any arbitrary linking group can be used as long as the effects of the present invention are not significantly impaired. Among these, an alkylene group having 1 to 6 carbon atoms and an alkenylene group are preferable. Among these, as R ^a , a direct bond and an alkylene group having 1 to 3 carbon atoms are more preferable, a direct bond and an alkylene group having 1 to 2 carbon atoms are particularly preferable, and a direct bond is particularly preferable.

  In the formula (A), Ar represents a divalent aromatic group which may be substituted. Here, the divalent aromatic group constituting Ar is not particularly limited as long as it is a divalent group having aromaticity. Therefore, any group having an aromatic ring can be used as Ar. For example, the aromatic ring itself may be used, or a group formed by combining an aromatic ring and an aliphatic hydrocarbon group. May be. However, among them, the aromatic group constituting Ar is preferably an aromatic ring itself, and among them, a hydrocarbon aromatic ring (that is, an arylene group) is more preferable.

  Moreover, there is no restriction | limiting in the kind of substituent which Ar may have, and it is arbitrary unless the effect of this invention is impaired remarkably. For example, a halogen group such as a fluoro group; a linear, branched or cyclic alkyl group having 1 to 24 carbon atoms, a fluorine-substituted alkyl group in which one or more fluoro groups are substituted on the alkyl group, a phenyl group An aryl group such as cyano group, carboxyl group, alkoxy group and the like; nitro group; amino group; sulfonic acid group; hydroxyl group and the like. In addition, Ar may have only 1 type of substituent and may have 2 or more types by arbitrary combinations and ratios. The number of substituents may be 1 or 2 or more.

  Furthermore, the carbon number of Ar is arbitrary as long as the effects of the present invention are not significantly impaired, but is usually 42 or less, preferably 18 or less, more preferably 14 or less. This is because if the number of carbon atoms is too large, the solubility may be poor. Moreover, although there is no restriction | limiting in a minimum, it is 4 or more normally.

  Examples of Ar include structures represented by the following formulas (i) to (xi). However, these are merely examples, and Ar applicable to the present invention is not limited to the structures of the following formulas (i) to (xi).

In addition, in said formula (i)-(xi), the definition of each code | symbol is as follows, respectively.
R ^{1 to} R ⁶⁸ are each independently H, F, CH ₃ —, CH ₃ (CH ₂ ) _n — (n represents an integer of 1 to 23), CH ₃ (CH ₂ ) _n (CF ₂ ) _m- (n and m each independently represents an integer of 1 to 23), CF _3- , CF ₃ (CF ₂ ) _n- (n represents an integer of 1 to 23), CF ₃ (CH ₂ ) _n (CF ₂ ) _m — (n and m each independently represents an integer of 1 to 23), phenyl group, nitro group, amino group, cyano group, carboxyl group, sulfonic acid Represents a group, a hydroxyl group, or an alkoxy group.

A ^{4 to} A ¹⁸ and A ^{20 to} A ³⁰ each independently represent a carbon atom or a nitrogen atom.
Q ^{1 to} Q ⁷ each independently represent —CR ⁶⁹ R ⁷⁰ —, —NR ⁷¹ —, —N—, —S—, —SiR ⁷² R ⁷³ —, or —Se— (R ^{69 to} R ^73). Each independently represents a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 23 carbon atoms, or a fluorine-substituted alkyl group in which the alkyl group is substituted with 1 or 2 or more fluorine atoms. Represent.)

を表わす。 E ¹ is a nitrogen atom or

Represents.

n ¹ and n ² each independently represents an integer of 0 or more and 6 or less.
n ³ and n ⁴ each independently represents an integer of 1 or more and 8 or less.
n ⁵ ~n ¹² each independently represent an integer of 0 to 10.

Among the above-described examples, a phenylene group in which n ² is 0 in formula (iii), a naphthalene group in which n ² is 1 and an anthracene group in which n ² is 3 are particularly preferable. Of these, a phenylene group and a naphthalene group are particularly preferable.

In the formula (A), R ^b represents a hydrogen atom, a fluorine atom or a monovalent organic group, and among them, a hydrogen atom or a linear or branched hydrocarbon group is preferable.
Specific examples of suitable monovalent organic groups include CH ₃ —, CH ₃ (CH ₂ ) _n — (n represents an integer of 1 to 23), CH ₃ (CH ₂ ) _n ( CF ₂ ) _m — (n and m each independently represents an integer of 1 to 23), CF ₃ —, CF ₃ (CF ₂ ) _n — (n represents an integer of 1 to 23) , CF ₃ (CH ₂ ) _n (CF ₂ ) _m — (wherein n and m each independently represents an integer of 1 to 23), an alkyl group optionally substituted with a fluorine atom; a phenyl group; Examples thereof include a carboxyl group substituted with a hydrocarbon group having 6 or less carbon atoms. Among them, particularly preferable as R ^b is a hydrogen atom, CH ₃ —, CF ₃ —, CH ₃ (CH ₂ ) _n — (n represents an integer of 1 to 23), carbonization of 6 or less carbon atoms. A carboxyl group substituted with a hydrogen group, and among them, a hydrogen atom, CH ₃ —, CH ₃ (CH ₂ ) _n — (n represents an integer of 1 to 23), carbonization of 6 or less carbon atoms A carboxyl group substituted with a hydrogen group is more preferable.

The repeating unit represented by the formula (A) can be said to be a repeating unit derived from a vinyl compound represented by the following formula (B). Therefore, from the viewpoint of monomers, the polymer insulator according to the present invention is referred to as a polyvinyl aromatic thiol and / or polyvinyl aromatic thioether derivative containing a repeating unit derived from a vinyl compound represented by the following formula (B). it can. In the following formula (B), R ^a , Ar and R ^b are all the same as in formula (A).

  Among the polymer insulators according to the present invention, those containing at least a repeating unit which is a phenylene group optionally substituted with Ar in the formula (A) are preferable. That is, the polymer insulator according to the present invention preferably contains at least one of repeating units derived from vinyl thiophenol, vinyl thioether and derivatives thereof. Among them, preferred are those having a repeating unit derived from a compound having the following structure (I).

In the formula (I), each R independently represents a hydrogen atom or a fluorine atom. I represents an integer of 1 or more, 5 or less, preferably 3 or less. When R is all hydrogen atoms, formula (I) represents vinylthiophenol, and when at least one of R is fluorine, formula (I) represents a vinylthiophenol derivative. R ^c represents a hydrogen atom or an alkyl group having 6 or less carbon atoms.

As described above, since the polymer insulator according to the present invention includes the structural unit represented by the formula (A), it has an aromatic thiol group and / or an aromatic thioether group. Thereby, the insulating layer of this invention can improve an element characteristic. In particular, when Ar is an optionally substituted phenylene group in the above formula (A), the degree of improvement is large. Furthermore, among these polymer insulators of the present invention, a repeating unit derived from vinylthiophenol and / or a vinylthiophenol derivative (that is, Ar is a phenylene group which may be substituted, and ^Rb is hydrogen. Those having a repeating unit represented by the formula (A) in the case of an atom (hereinafter referred to as “vinylthiophenol / derivative unit” as appropriate) are preferable because the above-described improvement effect is remarkable.

The reason why the above-described advantages can be obtained by having the structural unit represented by the formula (A) is not clear, but according to the study by the present inventors, an aromatic thiol group or an aromatic thioether group is added to the organic semiconductor. because the effect of removing the excess inherent carriers present, the insulating layer of the present invention is assumed to be effective in improving the reduction and on / Off ratio of the threshold voltage V _t. In principle, the same effect can be expected even when a reducing functional group is used instead of the aromatic thiol group or aromatic thioether group. However, when using, for example, amino group as the reducing functional group, the ability to remove the carrier is too strong, to act as a carrier trap, is Shiryo a significant reduction in the threshold voltage V _t is too occur. However, if it is a thiol group, there is no such concern, and it is speculated that the device characteristics can be effectively improved.

  In addition, the repeating unit represented by Formula (A) may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio. Therefore, when producing the polymer insulator according to the present invention, only one type of monomer corresponding to the repeating unit (that is, the compound represented by the formula (B) or (I)) may be used. You may use 2 or more types together by arbitrary combinations and a ratio.

The molar fraction of the repeating unit represented by the formula (A) in the polymer insulator according to the present invention is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.1 or more, preferably 0.2 or more. More preferably 0.3 or more, and usually 1 or less, preferably 0.7 or less, more preferably 0.5 or less. There is a possibility that when the repeating units too small threshold voltage V _t represented deteriorates by the formula (A). When the polymerization ratio is less than 1, the polymer insulator according to the present invention is a copolymer. The molar fraction of the can be measured by determining the ratio of SR ^b group by ¹ H-NMR.

  The polymer insulator according to the present invention may be a homopolymer of a vinyl compound represented by the formula (B), or may be a copolymer having other repeating units. The repeating unit other than the repeating unit represented by the formula (A) that the polymer insulator according to the present invention may have is not particularly limited, and any repeating unit can be used as long as the effects of the present invention are not significantly impaired. However, among them, there are repeating units derived from a crosslinkable vinyl monomer (hereinafter referred to as “crosslinkable vinyl monomer units” as appropriate) and repeating units derived from a heat resistant vinyl monomer (hereinafter referred to as “heat resistant vinyl monomer units” as appropriate). preferable.

  The crosslinkable vinyl monomer corresponding to the crosslinkable vinyl monomer unit is a monomer having a vinyl group and having a carbon-carbon double bond in the side chain when copolymerized. In this crosslinkable vinyl monomer, the carbon-carbon double bond undergoes a cyclization dimerization reaction by light irradiation or heating to form a crosslink by an alicyclic hydrocarbon group.

Although there is no restriction | limiting in the specific structure of a crosslinkable vinyl monomer, Among these, the vinyl monomer which has a side chain containing the structure of the following formula | equation (II)-(V) is preferable.

In formulas (IV) and (V), R ^c1 , R ^c2 , R ^c3 and R ^c4 each independently represent an aliphatic hydrocarbon group, a cyano group or a hydrogen atom.

  Among these side chains, a side chain including a structure represented by the formula (II) or (III) is preferable. Specific examples thereof include 2-propenoic acid group, 3-phenylpropenoic acid group (cinnamoyl group), 2,4-pentadienoic acid group, and 6-phenyl-2,4-pentadienoic acid group. Among them, 3-phenylpropenoic acid group (cinnamoyl group) or 6-phenyl-2,4-pentadienoic acid group is preferable, and 3-phenylpropenoic acid group (cinnamoyl group) is particularly preferable.

  Specific examples of preferred crosslinkable vinyl monomers include vinyl 3-phenylpropenoate and vinyl 6-phenyl-2,4-pentadienoate. Among these, vinyl 3-phenylpropenoate is particularly preferable.

  Since the crosslinkable vinyl monomer has a carbon-carbon double bond in the side chain, the crosslinkable vinyl monomers are cross-linked by the side chain during the crosslinking. Therefore, for example, a cyclobutylene group is generated as represented by the following formula (VI) by cyclization of the side chains including the structure represented by the above formula (II) or (IV) to cause dimerization. It will be. Further, for example, a side chain containing the structure represented by the above formula (II) or (IV) and a side chain containing a structure represented by the formula (III) or (V) are cyclized and dimerized. As a result, a cyclohexenylene group is generated as represented by the following formula (VII). Therefore, in the crosslinkable vinyl monomer unit, a crosslinked skeleton is formed by the cyclization reaction as described above, corresponding to the structure of the crosslinkable vinyl monomer. The cyclization reaction usually proceeds by light irradiation or heating, and preferably proceeds by light irradiation.

  Since the insulating layer of the present invention has a crosslinkable skeleton, it can be suitably used for an electronic device using an organic material such as an organic thin film transistor. For example, an organic thin film transistor will be described as an example. When an organic thin film transistor is formed by a solution process, the interface between the organic semiconductor layer and the organic insulating layer is in contact, and therefore the organic insulating layer is very likely to be damaged by the organic solvent. high. However, since the insulating layer of the present invention has a crosslinkable skeleton, it is insolubilized in the organic solvent used for forming the organic semiconductor layer. Therefore, when the insulating layer of the present invention is used as the organic insulating layer, it is possible to suppress the breakdown of the insulating layer due to the solution process, which is very effective.

The properties of the insulating layer of the present invention may change depending on the type of the crosslinkable skeleton. For example, when a crosslinkable skeleton is formed by performing a crosslinking reaction using polyvinylphenol or the like, polyvinylphenol has a polar group such as a hydroxyl group. Therefore, when the insulating layer of the present invention is used for an electronic device, it is a semiconductor. There is a possibility that a change in threshold voltage V _t due to doping of the results, an electronic device (in particular, organic thin-film transistor) is not preferred as a constituent member. However, if by crosslinking a crosslinkable vinyl monomer to obtain a crosslinked backbone, wherein the change in the threshold voltage V _t like to be suppressed, the use of insulating layers of the present invention suitable for an electronic device it can.

  The advantage obtained by using a combination of the above crosslinkable vinyl monomer units is particularly when the polymer insulator of the present invention contains a vinylthiophenol / derivative unit as a repeating unit represented by the formula (A). It is remarkable. Therefore, polyvinyl thiophenol containing at least a vinyl thiophenol / derivative unit and a crosslinkable vinyl monomer unit is very excellent as a constituent material of the insulating layer.

  In addition, a crosslinking | crosslinked vinyl monomer may use only 1 type and may use 2 or more types together by arbitrary combinations and a ratio. Accordingly, the cross-linkable vinyl monomer unit possessed by the polymer insulator according to the present invention may be only one type, or two or more types may be used in any combination and ratio.

When the polymer insulator according to the present invention contains a crosslinkable vinyl monomer unit, the molar fraction of the crosslinkable vinyl monomer unit in the polymer insulator according to the present invention is not limited, but is usually 0.1 or more, preferably Is 0.4 or more, more preferably 0.5 or more, and usually 0.9 or less, preferably 0.8 or less, more preferably 0.7 or less. If the amount of the crosslinkable vinyl monomer unit is too small, the advantage of having the crosslinkable vinyl monomer unit may not be sufficiently obtained, and the crosslinking density may be reduced and the insolubilizing effect with respect to the organic solvent may be lost. The effect (that is, the effect of removing excess carriers in the organic semiconductor) may be reduced. The molar fraction can be measured by ¹ H-NMR.

  On the other hand, the heat-resistant vinyl monomer corresponding to the heat-resistant vinyl monomer unit is a monomer having a vinyl group and having a predetermined heat resistance. Here, the heat resistance means that the glass transition temperature Tg is 140 ° C. or higher when the heat-resistant vinyl monomer is a homopolymer having a number average molecular weight of 1000.

  Although there is no restriction | limiting in the specific structure of a heat resistant vinyl monomer, Among them, what has a heat resistant frame | skeleton obtained from maleic anhydride and an amine is preferable, and maleimide is especially preferable. Examples of suitable maleimides include those having the structure of the following formula (VIII).

In the formula (VIII), R ^c5 represents a hydrogen atom or a group represented by the following formula (IX).

  In the formula (IX), each X independently represents a hydrogen atom, a fluorine atom or a nitro group, preferably a hydrogen atom or a fluorine atom. M represents an integer of 1 or more, preferably 2 or more, more preferably 3 or more, and 10 or less, preferably 8 or less, more preferably 6 or less.

Among the maleimides having the structure of the formula (VIII), those in which R ^c5 is a phenyl group are particularly preferable. This is because the phenyl group has no polar group and is sterically hindered with respect to the nitrogen atom of the imide group, so that the influence of the nitrogen atom can be reduced. When less affected nitrogen atom, for the nitrogen atom is a reducing group, because of the advantage that the threshold voltage V _t can be stably near 0, preferred.

  By including such a heat resistant vinyl monomer unit, the heat resistance of the polymer insulator according to the present invention can be improved. Specifically, the glass transition temperature of the polymer insulator according to the present invention can be usually 120 ° C. or higher, preferably 150 ° C. or higher, more preferably 180 ° C. or higher. An electronic device may generate heat during use. Therefore, the insulating layer is also required to have heat resistance. However, by improving the heat resistance of the polymer insulator according to the present invention, the heat resistance of the insulating layer of the present invention can be improved. Thus, it is possible to improve the stability of the operation of the electronic device.

  The advantage obtained by using a combination of the above heat-resistant vinyl monomer units is particularly advantageous when the polymer insulator of the present invention contains a vinylthiophenol / derivative unit as a repeating unit represented by the formula (A). It is remarkable. Therefore, polyvinyl thiophenol containing at least a vinyl thiophenol / derivative unit and a heat-resistant vinyl monomer unit is very excellent as a constituent material of the insulating layer.

  In addition, a heat resistant vinyl monomer may use only 1 type and may use 2 or more types together by arbitrary combinations and a ratio. Accordingly, the polymer insulator according to the present invention may have only one heat-resistant vinyl monomer unit, or two or more heat-resistant vinyl monomer units may be used in any combination and ratio.

When the polymer insulator according to the present invention contains a heat-resistant vinyl monomer unit, the molar fraction of the heat-resistant vinyl monomer unit in the polymer insulator according to the present invention is not limited, but is usually greater than 0, preferably 0.05 or more, more preferably 0.1 or more, and usually 0.5 or less, preferably 0.4 or less, more preferably 0.3 or less. If the heat-resistant vinyl monomer unit is too small, the advantage of having the heat-resistant vinyl monomer unit may not be sufficiently obtained, and sufficient heat resistance may not be obtained. There is a possibility of trapping. In addition, when the crosslinkable vinyl monomer unit is contained in a large amount in the polymer insulator according to the present invention, the heat resistance increases as the crosslink density increases, so that sufficient heat resistance can be obtained without using a heat resistant vinyl monomer unit. It may be possible to obtain sex. The molar fraction can be measured by ¹ H-NMR.

Moreover, the polymer insulator according to the present invention may have a repeating unit other than the repeating unit represented by the formula (A), the crosslinkable vinyl monomer unit, and the heat-resistant vinyl monomer unit.
However, it is preferable that none of the repeating units contained in the polymer insulator according to the present invention has a polar group. Even if the repeating unit contained in the polymer insulator according to the present invention has a polar group, the number is preferably small. Specifically, the average number per repeating unit contained in the polymer insulator according to the present invention is preferably 1 or less, more preferably 0.5 or less, and More preferably, it is 4 or less. When the polymer insulator contained in the insulating layer of the present invention has many polar groups, it tends to cause moisture adhesion in the insulating layer and on the surface of the layer, thereby, for example, a semiconductor layer adjacent to the insulating layer, etc. to occur doped with moisture, and there is a tendency that the off current is generated and the change in increase and the threshold voltage V _t.

Further, when the polymer insulator according to the present invention is a copolymer, there is no limitation on the polymerization type, and any polymerization such as a random copolymer, an alternating copolymer, a block copolymer, a graft copolymer, etc. It may be in the form. Among these, an alternating copolymer and a random copolymer are preferable. This is because SR ^b groups in the copolymer are uniformly dispersed.

  Preferable specific examples of the polymer insulator according to the present invention include those having a structure represented by the following formula (X).

In the formula (X), R ^c6 represents the same as R ^c5 described in formula (VIII), and R ^c7 represents a side chain containing the structures of (II) to (V). _{Further, n 1: n 2: n} 3 = 0.1: 0.3: 0.6. In the formula (X), the parentheses represent repeating units, and the order of bonding of these repeating units is not limited to the order in the formula.

  The weight average molecular weight of the polymer insulator of the present invention is arbitrary as long as the effect of the present invention is not significantly impaired, but is preferably 5,000 or more, more preferably 10,000 or more, and preferably 1,000,000. 000 or less, more preferably 100,000 or less. If the weight average molecular weight is too small, there is a possibility that the film formability and insulation of the insulating layer of the present invention cannot be improved, and if it is too large, the viscosity increases when the polymer insulator of the present invention is made into a solution. May cause the film to become thin.

Although there is no restriction | limiting in the manufacturing method of the polymer insulator based on this invention, For example, it can obtain by superposing | polymerizing the vinyl compound represented by Formula (B). Further, when R ^b is a hydrogen atom, that is, when SR ^b is a thiol group, it can be produced by preliminarily carrying out the polymerization while protecting the thiol group and performing a deprotection reaction after the polymerization. Since a thiophenol group or the like easily generates a dissociated radical, a polymer may not be obtained if the thiophenol group or the like is left, but can be stably polymerized by introducing a protective group. Hereinafter, this method will be described in detail by taking as an example the case of producing polyvinyl thiophenol as a polymer insulator according to the present invention from vinyl thiophenol and / or a vinyl thiophenol derivative.

  First, a vinyl thiophenol and / or vinyl thiophenol derivative as a monomer is prepared, and the thiophenol group is protected with a protective group (protection step). The protecting group is not particularly limited as long as the thiophenol group can be protected, and for example, an acetyl group, a t-butoxycarbonyl group (t-BOC group), and the like are preferable. In addition, 1 type may be used for a protecting group and it may use 2 or more types together by arbitrary combinations and a ratio. Further, there is no limitation on the protection method. For example, when protecting with an acetyl group, it can be protected by treating the thiol group with a base and reacting with an acid chloride such as acetyl chloride.

After protecting the thiophenol group, the polymerization reaction is allowed to proceed while maintaining the predetermined reaction conditions in the reaction solvent (polymerization step).
As the reaction solvent, any solvent can be used as long as it does not inhibit the polymerization reaction. Usually, an organic solvent is used, and preferably a solvent usually used for polymerizing a vinyl polymer such as tetrahydrofuran and toluene can be used. In addition, 1 type may be used for the reaction solvent and it may use 2 or more types together by arbitrary combinations and a ratio.

  The concentration of the monomer in the reaction solvent is not limited as long as the polymerization reaction proceeds, but is usually 0.001 mol / L or more, preferably 0.002 mol / L or more, more preferably 0.003 mol / L or more, and usually 100 mol. / L or less, preferably 80 mol / L or less, more preferably 60 mol / L or less. If the monomer concentration in the reaction solvent is too low, the molecular weight may be too low, and if it is too high, the molecular weight may be too high.

  The temperature condition during the polymerization reaction is not limited as long as the polymerization reaction proceeds, but is usually 25 ° C or higher, preferably 30 ° C or higher, more preferably 35 ° C or higher, and usually 150 ° C or lower, preferably 140 ° C or lower, More preferably, it is 130 degrees C or less. If the reaction temperature is too low, the polymerization does not proceed and the polymer may not be formed. On the other hand, if the reaction temperature is too high, the monomer boils and the copolymerization ratio may not be a desired value when copolymerization is performed.

  The reaction time is not limited, but is usually 1 hour or longer, preferably 3 hours or longer, more preferably 5 hours or longer, and usually 24 hours or shorter, preferably 20 hours or shorter, more preferably 18 hours or shorter. If the reaction time is too short, the molecular weight may be too low, and if it is too long, the molecular weight may be too high.

  The atmosphere during the reaction is preferably an inert atmosphere. For example, a nitrogen atmosphere or a vacuum seal is preferable.

  When a polymerization initiator is used in the polymerization reaction, any polymerization initiator can be used as long as the polymerization reaction proceeds. Examples thereof include azobisisobutyronitrile (AIBN), benzoyl peroxide (BPO), and the like. Moreover, 1 type may be used for a polymerization initiator and it may use 2 or more types together by arbitrary combinations and a ratio. Moreover, although there is no restriction | limiting in the usage-amount, in a reaction solution, it is 0.01 mol% or more normally, Preferably it is 0.02 mol% or more, and is 10 mol% or less normally, Preferably it is 8 mol% or less.

  Further, when the polyvinylthiophenol has a repeating unit other than the repeating unit represented by the formula (A), other monomers corresponding to the repeating unit (for example, a crosslinkable vinyl monomer or heat resistance) are contained in the reaction solvent. Vinyl monomer, etc.) may be allowed to coexist. Therefore, in order for the polymer insulator according to the present invention to have a crosslinkable vinyl monomer unit, the crosslinkable vinyl monomer is allowed to coexist in the reaction solvent, and the polymer insulator according to the present invention is a heat resistant vinyl. In order to have a monomer unit, a heat-resistant vinyl monomer is allowed to coexist in the reaction solvent. Thereby, copolymerization of vinylthiophenol and / or a vinylthiophenol derivative and other monomers such as a crosslinkable vinyl monomer and a heat-resistant vinyl monomer proceeds (copolymerization step).

When copolymerization is performed, the amounts of the crosslinkable vinyl monomer and the heat resistant vinyl monomer in the reaction solvent are respectively the mole fraction of the crosslinkable vinyl monomer unit and the heat resistant vinyl monomer unit in the polymer insulator according to the present invention. You can set as well.
The reaction conditions for carrying out copolymerization can be carried out under the same conditions as for homopolymerization of vinylthiophenol and / or vinylthiophenol derivatives. However, when copolymerizing a crosslinkable monomer, it is preferable to polymerize under light shielding conditions. This is because there is a possibility that a crosslinkable site such as silicic acid reacts unless light is blocked.

After the polymerization, deprotection is carried out by removing the protecting group that protected the thiophenol group to obtain polyvinylthiophenol as a polymer insulator according to the present invention (deprotection step). The method of deprotection is arbitrary. For example, after the polymer obtained by polymerization is treated with a base such as sodium hydroxide, hydrochloric acid is added to form a thiol. If this deprotection is not performed, a polymer insulator having the introduced protective group as R ^b can be obtained.

  Further, purification is usually performed after deprotection (purification step). Although there is no restriction | limiting in the refinement | purification method, For example, it can refine | purify by reprecipitating with purification solvents, such as hexane and methanol, and wash | cleaning with washing solvents, such as methanol. As the cleaning method, Soxhlet cleaning is preferable.

  When polyvinylthiophenol is produced as a polymer insulator according to the present invention by such a production method, the yield is usually 60% or more, preferably 70% or more, more preferably 80% or more. The upper limit of the yield is ideally 100%, but is practically 98% or less.

In addition, when producing a polymer insulator according to the present invention other than polyvinylthiophenol, if the type of monomer is changed and the conditions of each step are optimized, the purpose is the same as in the above production method. Can be produced.
In addition, according to the manufacturing method described above, the polymer insulator according to the present invention is manufactured from the monomer. However, the monomer is once made into an oligomer and the oligomer is polymerized, or the monomer and the oligomer are combined. The polymer insulator of the present invention may be produced by polymerization.

[I-2. Insulation layer properties]
The electric conductivity of the insulating layer of the present invention is not limited as long as the insulating property required according to the application can be secured, but is usually 1 × 10 ⁻¹² S / cm or less, preferably 1 × 10. ⁻¹³ S / cm or less, more preferably 1 × 10 ⁻¹⁴ S / cm or less. If the electrical conductivity is too high, leakage current may increase when a transistor is formed using the insulating layer of the present invention. On the other hand, although there is no restriction on the lower limit, it is usually 1 × 10 ⁻¹⁶ S / cm or more. The electrical conductivity can be measured by current-voltage measurement.

  The thickness of the insulating layer of the present invention is not limited and can be arbitrarily set depending on the application, but is usually 10 nm or more, preferably 50 nm or more, more preferably 100 nm or more, and usually 3 μm or less, preferably 2 μm. Below, more preferably 1 μm or less. If the thickness of the insulating layer of the present invention is too thin, there is a possibility of increasing the leakage current when the transistor is configured using the insulating layer of the present invention. If the thickness is too thick, the transistor is formed using the insulating layer of the present invention. When configured, there is a possibility that sufficient drain current cannot be secured.

[I-3. Insulating layer formation method]
Although there is no restriction | limiting in the formation method of the insulating layer of this invention, For example, it can form by printing, spin coating, dipping (dipping) etc. If a specific example is given, it can manufacture with the following method.

  First, the polymer insulator according to the present invention is dissolved in an appropriate solvent to prepare a coating solution. And this insulating liquid can be formed by apply | coating this coating liquid to the site | part which is going to form an insulating layer by the method of the said illustration, etc., and removing a solvent by drying etc. after that.

  As the solvent for preparing the coating solution, any solvent can be used as long as it can dissolve the polymer insulator according to the present invention. Examples thereof include dimethylformamide. In addition, 1 type may be used for these solvents and 2 or more types may be used together by arbitrary combinations and a ratio.

  The concentration of the polymer insulator in the coating solution is not particularly limited, but is usually 1% by weight or more, preferably 3% by weight or more, more preferably 5% by weight or more, and usually 50% by weight or less, preferably 30% by weight. % Or less, more preferably 20% by weight or less. If the concentration of the coating solution is too low, it may be difficult to remove the solvent. If the concentration is too high, the viscosity may increase and the film formability may be reduced.

When removing the coating solution by drying, heat drying may be used, vacuum drying may be used, or both may be used in combination. There are no restrictions on temperature conditions, pressure conditions, drying time, and the like. However, the temperature condition is usually higher than the boiling point of the solvent used, and the specific temperature range is usually 50 ° C. or higher, preferably 80 ° C. or higher, more preferably 100 ° C. or higher, and usually 300 ° C. or lower, preferably 250 ° C. or lower, more preferably 200 ° C. or lower. The pressure condition is usually 1 Pa or more, preferably 5 Pa or more, more preferably 10 Pa or more, and usually 10 ⁵ Pa or less, preferably 10 ⁴ Pa or less, more preferably 10 ³ Pa or less. Furthermore, the drying time is usually 3 minutes or longer, preferably 5 minutes or longer, more preferably 10 minutes or longer, and usually 120 minutes or shorter, preferably 90 minutes or shorter, more preferably 60 minutes or shorter.

  However, when the polymer insulator according to the present invention has a crosslinkable vinyl monomer unit, when crosslinked, the polymer insulator according to the present invention does not dissolve in a solvent, and an insulating layer can be formed by a coating process. There is a possibility of disappearing. For this reason, when the polymer insulator according to the present invention has a crosslinkable vinyl monomer unit, it is preferable that the crosslinking does not proceed before coating of the coating solution, but proceeds after coating. In addition, if the polymer insulator according to the present invention is in a liquid state before crosslinking, the polymer insulator according to the present invention is applied without using a solvent, and the crosslinking reaction is allowed to proceed. The molecular insulator may be cured to form an insulating layer. In order to advance the crosslinking reaction, light irradiation or heating may be performed as described above.

[I-4. Effect of insulating layer of the present invention]
By using the insulating layer of the present invention, the element characteristics of the electronic device can be improved.
For example, when an electronic device such as a field effect transistor having a semiconductor layer is provided with the insulating layer of the present invention, the charge mobility in the semiconductor layer is usually 10 ⁻⁵ cm ² / Vs or more, preferably 10 ^−3. cm ² / Vs or more, more preferably 10 ⁻² cm ² / Vs or more. In addition, although there is no restriction | limiting in an upper limit, Usually, it is 10000 cm < ² > / Vs or less. The mobility can be measured by a normal semiconductor measurement method.

For example, when a transistor is provided with the insulating layer of the present invention, the On / Off ratio of the transistor is usually 100 or more, preferably 1000 or more, more preferably 10,000 or more. The upper limit is not limited, but is usually 10 ⁸ or less. The On / Off ratio can be measured by a normal semiconductor measurement method.
Furthermore, for example, when allowed comprising an insulating layer of the present invention to a transistor, the threshold voltage V _t of the transistor is generally ± 20 or less, preferably ± 10 or less, more preferably ± 5 or less. The threshold voltage V _t can be measured by a usual semiconductor measurement.
The insulating layer of the present invention may contain components other than the polymer insulator according to the present invention as long as the effects of the present invention are not significantly impaired.

[II. Electronic device]
The insulating layer of the present invention can be arbitrarily applied to an electronic device including the insulating layer, and is particularly suitable for an electronic device using an organic semiconductor. Examples of such electronic devices include transistors. Among them, it is preferably used for a transistor, and particularly preferably used for an organic thin film transistor. Among transistors, according to functional classification, they are suitable for field effect transistors (FETs). Hereinafter, a field effect transistor will be described as an example of an electronic device including the insulating layer of the present invention. However, the configurations of the electronic device and the field effect transistor of the present invention are not limited to those exemplified below, and any configuration can be used as long as the insulating layer of the present invention is provided.

  The field effect transistor includes a gate electrode and a semiconductor layer which are separated from each other by an insulating layer, and a source electrode and a drain electrode which are provided in contact with the semiconductor layer on a supporting substrate. When a voltage is applied to the gate electrode, a current flow channel (channel) is formed at the interface between the semiconductor layer between the source electrode and the drain electrode and the adjacent layer. With this configuration, the field effect transistor has a mechanism for controlling the current flowing between the source electrode and the drain electrode by the input voltage applied from the gate electrode.

  The structure of the field effect transistor will be described with reference to the drawings. FIGS. 1A to 1D are vertical sectional views each schematically showing a typical structure of the field effect transistor. In FIG. 1D, 1 represents a supporting substrate, 2 represents a gate electrode, 3 represents an insulating layer, 4 represents a semiconductor layer, 5 represents a source electrode, and 6 represents a drain electrode. 1A is a bottom gate / bottom contact type, FIG. 1B is a bottom gate / top contact type, FIG. 1C is a top gate / bottom contact type, and FIG. Although a top gate / top contact type field effect transistor is shown, the configuration of the field effect transistor is not limited to these examples. Further, although not shown, an overcoat layer may be formed at the top of each field effect transistor in the drawing.

<Support substrate>
In the field effect transistor, the supporting substrate 1 may be a substrate used in a conventional field effect transistor. Any material can be used as long as it can support a field effect transistor and a display element, a display panel, and the like manufactured thereon. Examples thereof include known glass, inorganic materials such as silicon oxide and metals such as silicon, and organic materials such as various organic polymers. In addition, these may be used alone, including, for example, a case where an inorganic material such as a substrate in which an organic polymer is coated on the surface of an inorganic material substrate and an insulating layer is formed on the surface and an organic material in combination. Two or more kinds can be used in combination. Examples of the organic polymer include polyester, polycarbonate, polyimide, polyamide, polyether sulfone, epoxy resin, polybenzoxazole, polybenzothiazole, polyparabanic acid, polysilsesquioxane, polyvinylphenol, and polyolefin. . Furthermore, these organic polymers may contain a filler, an additive, etc. as needed.

  The thickness of the support substrate is not limited, but is usually 0.01 mm or more, preferably 0.05 mm or more, and usually 10 mm or less, preferably 2 mm or less. Within these ranges, for example, in the case of an organic polymer substrate, the thickness is preferably 0.05 to 0.1 mm, and in the case of a glass or silicon substrate, the thickness is preferably 0.1 to 10 mm. Further, the substrate may be a laminate composed of a plurality of layers.

<Gate electrode>
In the field effect transistor, as the gate electrode 2, a conductive material used in a conventional field effect transistor can be used. For example, metals such as platinum, gold, silver, aluminum, chromium, nickel, copper, titanium, magnesium, calcium, barium and sodium; conductive metal oxides such as InO ₂ , SnO ₂ and ITO; polyaniline, polypyrrole, polythiophene, Conductive polymers such as polyacetylene; acids such as hydrochloric acid, sulfuric acid and sulfonic acid, Lewis acids such as PF ₆ , AsF ₅ and FeCl ₃ , halogen atoms such as iodine, metals such as sodium and potassium Examples thereof include a material to which a dopant such as an atom is added, and a conductive composite material in which carbon black, graphite powder, metal fine particles and the like are dispersed. Moreover, 1 type may be used for these materials and it may use 2 or more types together by arbitrary combinations and a ratio.

  There is no limitation on the method for forming the gate electrode using these conductive materials, but for example, a film formed by a vacuum deposition method, a sputtering method, a coating method, a printing method, a sol-gel method, or the like is formed into a desired shape as necessary. It is formed by patterning. The patterning method is not limited, but, for example, a photolithographic method that combines photoresist patterning and etching such as wet etching with an etchant or dry etching with reactive plasma, ink jet printing, screen printing, offset Examples thereof include a printing method such as printing and letterpress printing, a soft lithography method such as a microcontact printing method, and a method combining a plurality of these methods. It is also possible to directly form a pattern by irradiating an energy beam such as a laser or an electron beam to remove the material or changing the conductivity of the material.

  Although the thickness of these gate electrodes is arbitrary, it is preferably 1 nm or more, and particularly preferably 10 nm or more. Moreover, it is preferable that it is 100 nm or less, and it is especially preferable that it is 50 nm or less.

<Insulating layer>
As the insulating layer 3, the insulating layer of the present invention is used.

<Semiconductor layer>
Although there is no restriction | limiting in the semiconductor used for the semiconductor layer 4, It is preferable to use an organic semiconductor from a viewpoint of utilizing the advantage of this invention effectively. As the organic semiconductor, for example, any known one can be used as long as it is a π-conjugated low molecular weight polymer. Specific examples include porphyrin, pentacene, copper phthalocyanine, polythiophene, oligothiophene, polyaniline, polyacetylene, polypyrrole, polypyrrole, and polypyrrole. These derivatives are exemplified. Among these, porphyrin, polythiophene, and oligothiophene are preferable, and porphyrin is more preferable. When a semiconductor layer containing porphyrin is used, there is an advantage that an on / off ratio (on / off ratio) in the case of a field effect transistor is increased and a threshold voltage Vt is improved. In addition, 1 type may be used for a semiconductor and it may use 2 or more types together by arbitrary combinations and a ratio.

Further, among the semiconductors, the carrier density obtained from the field effect mobility, the electric conductivity in the source electrode-drain electrode direction, and the elementary charge as the semiconductor layer is 1 × 10 ⁷ / cm ³ or more. Preferably, it is 1 × 10 ⁸ / cm ³ or more, more preferably 1 × 10 ¹⁸ / cm ³ or less, and more preferably 1 × 10 ¹⁷ / cm ³ or less. If the carrier density is too low, it may not be a semiconductor, and if it is too high, off current may increase.

  Although there is no restriction | limiting in the formation method of a semiconductor layer, For example, in the case of an organic semiconductor layer, it can form by carrying out solution processing and drying by well-known methods, such as spin coating, stamp printing, screen printing, and jet printing.

  The thickness of the semiconductor layer is arbitrary, but is preferably 1 nm or more, and more preferably 10 nm or more. Further, it is preferably 10 μm or less, more preferably 1 μm or less, and particularly preferably 500 nm or less.

<Source electrode, drain electrode>
In the field effect transistor, the source electrode 5 is an electrode through which current flows from the outside through the wiring, and the drain electrode 6 is an electrode that sends current to the outside through the wiring, and is provided in contact with the semiconductor layer 4 described above. . In the field effect transistor, the material of the source electrode 5 and the drain electrode 6 can be a conductive material used in a conventional field effect transistor, for example, the same material as the material of the gate electrode 2. Is mentioned.

  Further, the source electrode and drain electrode are formed using these conductive materials by the same film formation method and patterning method as those described above as the film formation method of the gate electrode and the patterning method as necessary. Furthermore, a pattern can also be formed directly by irradiating an energy beam such as a laser or an electron beam to remove a portion outside the electrode or changing the conductivity of the electrode material.

  Among these, a photolithography method is preferable as the patterning method for the source electrode and the drain electrode. As the photolithography method, an electrode material is formed, and a portion outside the electrode of the film is removed by etching, and a pattern is applied to the portion outside the electrode by applying a resist or the like, and then an electrode is formed thereon. The material is formed into a film, and then is roughly divided into a method (lift-off method) for removing the electrode material formed thereon by eluting with a solvent that dissolves the resist or the like. The former method of removing the portion outside the electrode of electrode material film formation by etching is preferable. Note that when etching is performed, an insulating layer containing a polyvinyl aromatic thioether derivative is preferably used from the viewpoint of resistance to an etching solution.

Although the thickness of a source electrode and a drain electrode is arbitrary, 1 nm or more is preferable and 10 nm or more is especially preferable. Moreover, 100 nm or less is preferable and 50 nm or less is especially preferable.
Further, the distance (channel length L) between the source electrode and the drain electrode is also arbitrary, but is preferably 100 μm or less, and particularly preferably 50 μm or less. Further, the channel width W is preferably 2000 μm or less, and particularly preferably 500 μm or less. Further, L / W is preferably 1 or less, and particularly preferably 0.1 or less.

<Overcoat layer>
In the field effect transistor, examples of the material for the overcoat layer include organic polymers such as polystyrene, acrylic resin, polyvinyl alcohol, polyolefin, polyimide, polyurethane, and epoxy resin, metal oxides such as silicon oxide, aluminum oxide, and silicon nitride, Examples thereof include inorganic substances such as nitrides. In addition, these may use 1 type and may use 2 or more types together by arbitrary combinations and ratios.

  There is no restriction | limiting in the formation method of an overcoat layer, Well-known various methods can be used arbitrarily. For example, when the overcoat layer is made of an organic polymer, a method of applying the solution and then drying to form an organic polymer layer, a method of applying these monomers and then polymerizing to form a polymer layer, etc. Further, post-treatment such as cross-linking treatment may be appropriately performed after film formation. Further, for example, when the overcoat layer is made of an inorganic material, a method using a sputtering method, a vapor deposition method, or the like, a method using a solution typified by a sol-gel method, or the like can be given. Further, a plurality of overcoat layers can be formed to enhance the effect.

<Other layers>
In addition to the supporting substrate 1, the gate electrode 2, the insulating layer 3, the semiconductor layer 4, the source electrode 5, the drain electrode 6, and the overcoat layer, the field effect transistor may be provided with one layer or two or more layers. . Further, the position where these are provided is arbitrary as long as the function of the field effect transistor is not hindered.

[III. Others]
By the way, among the polymer insulators described in the section of the polymer insulator according to the present invention, at least a vinylthiophenol / derivative unit and one or both of a crosslinkable vinyl monomer unit and a heat-resistant vinyl monomer unit are included. Polyvinyl thiophenol is a novel polymer not conventionally known. This novel polymer is a substance having excellent properties as described above, and is expected to be applied to various uses including the use as the material of the insulating layer of the present invention. Accordingly, polyvinylthiophenol containing at least a vinylthiophenol / derivative unit and a repeating unit derived from a crosslinkable vinyl monomer, and polyvinylthiol containing at least a vinylthiophenol / derivative unit and a repeating unit derived from a heat-resistant vinyl monomer Phenol is also included in the technical scope of the present invention.

  EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples. However, these examples are for explaining the present invention, and the present invention is not limited to the following examples, and is arbitrary within a range not departing from the gist thereof. You can change it to

[Synthesis Example 1: Synthesis of p-vinylbenzenethiol]
Under a nitrogen atmosphere at room temperature, 1.64 g of Mg powder was dispersed in 53 mL of tetrahydrofuran (THF), and 8 mL of 4-bromostyrene (manufactured by Aldrich) was slowly added dropwise. In order to suppress an increase in reaction heat during the course, cooling was performed stepwise and cooled to −15 ° C. to prepare a Grignard reaction liquid. Sulfur powder (manufactured by Aldrich) was added to the reaction solution at this temperature and gradually returned to 0 ° C. over 3 hours. After 3 hours, 1N NaOH aqueous solution was added to the reaction solution and stirred. The reaction solution was filtered and separated with ether. The aqueous layer was collected and concentrated under reduced pressure at room temperature. When this aqueous layer was gradually adjusted to pH 6.5 by adding 1N HCl, it was colored pale yellow. The aqueous layer was separated with benzene, and the organic layer was dried over sodium sulfate and concentrated to obtain p-vinylbenzenethiol as the target product.
As a result of measuring the ¹ H-NMR and GC-MS of the obtained product were as follows.
¹ H-NMR: 3.45 (—SH, s, 1H), 7.02-7.38 (—C ₆ H ₄ —, m, 4H).
GC-MS: m / e = 136.
In addition, FIG. 2 shows a mass spectrometry spectrum of p-vinylbenzenethiol obtained in Synthesis Example 1.

[Synthesis Example 2: Thiol protection by acetyl group]
Under a nitrogen atmosphere at −5 ° C., 2.7 g of p-vinylbenzenethiol obtained in Synthesis Example 1 was dissolved in 300 mL of THF, and 10 mL of pyridine was added as a deoxidizing agent. The mixture was stirred well for 1 hour, and then 3 g of acetyl chloride was slowly added dropwise. After stirring for 1 hour, pyridine hydrochloride was precipitated by stirring for 1 hour. The pyridine hydrochloride was separated by filtration, and the filtrate was concentrated under reduced pressure at low temperature, and further subjected to liquid separation extraction with benzene and water, and the organic layer was concentrated under reduced pressure at low temperature to obtain a pale yellow liquid. This liquid was purified by alumina column chromatography (methylene chloride) to obtain p-vinylbenzenethiol with an acetyl protecting group as a target product.
As a result of measuring the ¹ H-NMR and GC-MS of the obtained product were as follows.
¹ H-NMR: 7.02-7.38 (—C ₆ H ₄ —, m, 4H).
GC-MS: m / e = 178.

[Synthesis Example 3: Mercapto Group-Containing Polymer A (Copolymerization)]
1.8 g of p-vinylbenzenethiol with an acetyl protecting group purified in Synthesis Example 2 and 1.7 g of vinyl cinnamate (manufactured by Aldrich) = 1: 1 were dissolved in THF at a concentration of 10% by weight in a light-shielded state. A polymerization initiator 2,2′-azobis-isobutyronitrile (manufactured by Kishida Chemical Co.) was added at a ratio of 0.01 mol% with respect to the monomer, and the mixture was heated to reflux for 8 hours. After completion of the reaction, the reaction solution was poured into methanol for reprecipitation to obtain a white solid polymer. As a result of GPC measurement in terms of polystyrene, the number average molecular weight was 30,000, and the weight average molecular weight was 90,000. The acetyl group deprotection reaction of the obtained polymer was performed by dissolving the polymer again in a mixed solution of sodium hydroxide aqueous solution and THF and reprecipitating it in 1N hydrochloric acid aqueous solution. The polymer subjected to the deprotection reaction was dried under reduced pressure to obtain a polymer A having the following structural formula. In the following structural formulas, the parenthesized units represent repeating units, and the bonding order and polymerization ratio of these repeating units are not limited to the following structural formulas.

[Synthesis Example 4: Mercapto group-containing polymer B (copolymerization ternary system)]
1.8 g of p-vinylbenzenethiol with an acetyl protecting group purified in Synthesis Example 2, 0.9 g of vinyl cinnamate (manufactured by Aldrich) and 0.5 g of maleic anhydride (manufactured by Aldrich) = 2: 1: 1 in a light-shielded state, Dissolve in THF at a concentration of 10% by weight in nitrogen, add a polymerization initiator 2,2′-azobis-isobutyronitrile (manufactured by Kishida Chemical Co.) at a ratio of 0.01 mol% to the monomer, and heat for 8 hours Reflux was performed. After completion of the reaction, the reaction solution was poured into methanol for reprecipitation to obtain a white solid polymer. This polymer was dissolved in 200 mL of N-methylpyrrolidone, 100 mL of aniline was added in a light-shielded state under a nitrogen atmosphere, and the mixture was heated to reflux for 3 hours. After completion of the reaction, the mixture was reprecipitated in a 1N hydrochloric acid aqueous solution, and the acetyl group was deprotected together to obtain a white solid polymer. As a result of GPC measurement in terms of polystyrene, the number average molecular weight was 20,000 and the weight average molecular weight was 70,000. The acetyl group deprotection reaction of the obtained polymer was performed by dissolving the polymer again in a mixed solution of sodium hydroxide aqueous solution and THF and reprecipitating it in 1N hydrochloric acid aqueous solution. The polymer subjected to the deprotection reaction was dried under reduced pressure to obtain a polymer B having the following structural formula. In the following structural formulas, the parenthesized units represent repeating units, and the bonding order and polymerization ratio of these repeating units are not limited to the following structural formulas.

[Synthesis Example 5: Mercapto Group-Containing Polymer C (Homopolymerization)]
1.8 g of p-vinylbenzenethiol with an acetyl protecting group purified in Synthesis Example 2 was dissolved in THF at a concentration of 10% by weight in nitrogen, and a polymerization initiator 2,2′-azobis-isobutyronitrile (manufactured by Kishida Chemical Co., Ltd.). ) Was added at a ratio of 0.01 mol% with respect to the monomer, and the mixture was refluxed for 8 hours. After completion of the reaction, the reaction solution was poured into methanol for reprecipitation to obtain a white solid polymer. As a result of GPC measurement in terms of polystyrene, the number average molecular weight was 29,000 and the weight average molecular weight was 88,000. The acetyl group deprotection reaction of the obtained polymer was performed by dissolving the polymer again in a mixed solution of sodium hydroxide aqueous solution and THF and reprecipitating it in 1N hydrochloric acid aqueous solution. The polymer subjected to the deprotection reaction was dried under reduced pressure to obtain a polymer C having the following structural formula.

[Synthesis Example 6: Thiol Protection with Methyl Group]
0.9 g of p-vinylbenzenethiol obtained in Synthesis Example 1 was dissolved in 100 mL of THF at −5 ° C. in a nitrogen atmosphere, and 50 mL of pyridine was added as a deoxidizing agent. The mixture was stirred well for 1 hour, and then 1 g of iodomethane was slowly added dropwise. After completion of dropping, the mixture was stirred at low temperature for 2 hours. After completion of the reaction, the reaction solution was concentrated under reduced pressure at low temperature, and further subjected to liquid separation extraction with diethyl ether and water, and the organic layer was concentrated under reduced pressure at low temperature to obtain a pale yellow liquid. This liquid was purified by alumina column chromatography (methylene chloride) to obtain p-vinylbenzenethiol with a methyl protecting group as a target product.
As a result of measuring the ¹ H-NMR and GC-MS of the obtained product were as follows.
¹ H-NMR: 7.00-7.34 (—C ₆ H ₄ —, m, 4H).
GC-MS: m / e = 151.

[Synthesis Example 7: Mercapto Group-Containing Polymer D (Copolymerization)]
Polymerization initiator 2 was prepared by dissolving 1.5 g of p-vinylbenzenethiol with methyl protecting group and 0.87 g = 1: 1 vinyl acetate (manufactured by Aldrich) purified in Synthesis Example 6 in THF at a concentration of 10% by weight in nitrogen. 2,2′-Azobis-isobutyronitrile (manufactured by Kishida Chemical Co., Ltd.) was added at a ratio of 0.01 mol% with respect to the monomer, and the mixture was heated to reflux for 8 hours. After completion of the reaction, the reaction solution was poured into methanol for reprecipitation to obtain a white solid polymer. This white polymer was dissolved in 100 mL of pyridine, and 1.5 g of cinnamic acid chloride was slowly added dropwise. After completion of the dropwise addition, pyridine hydrochloride was precipitated by stirring at a low temperature for 2 hours. The pyridine hydrochloride was separated by filtration, and the filtrate was poured into methanol for reprecipitation, thereby obtaining a polymer D having the following structural formula as a white solid. In the following structural formulas, the parenthesized units represent repeating units, and the bonding order and polymerization ratio of these repeating units are not limited to the following structural formulas. As a result of GPC measurement in terms of polystyrene, the number average molecular weight was 30,000, and the weight average molecular weight was 90,000.

[Example 1]
Patterning is performed on an ITO glass plate (Toyo Sangyo Co., Ltd., 2.5 cm x 2.5 cm) using a photoresist ("ZPN1100" manufactured by Nippon Zeon Co., Ltd.) to dissolve 1 wt% iron (II) chloride. Further, unnecessary ITO was etched with 1N aqueous hydrogen chloride solution and washed to form a gate electrode. Then, a 10 wt% N-methylpyrrolidone solution of polymer A obtained in Synthesis Example 3 (pressure-filtered with a 0.2 μm PTFE filter) was spin-coated at a rotation speed of 2000 rpm to form a film. A film having a thickness of 3000 mm was produced. The film was irradiated with ultraviolet rays by an ultraviolet exposure apparatus using an ultra-high pressure mercury lamp to carry out a photocrosslinking reaction of the cinnamic acid portion, and insolubilized in a solvent to form a gate insulating layer. Subsequently, patterning is performed on the gate insulating layer by photolithography (Nagase Chemtex Corp .: positive lift-off resist NPR9700T) to form a source electrode and a drain electrode. As a result, a source electrode and a drain electrode were formed with a gap (L) of 10 μm and a width (W) of 500 μm, and a 0.7 wt% chloroform solution of a porphyrin compound having the following structure was spin-coated thereon, and 180 ° C. 1 for 10 minutes to convert the porphyrin compound into tetrabenzoporphyrin, thereby having a semiconductor layer made of tetrabenzoporphyrin, and a bottom gate / bottom contact type field effect transistor shown in FIG. Was made. Note that layer formation and electrode formation were all performed in a nitrogen atmosphere.

The field effect transistor obtained above was measured for mobility μ, threshold voltage V _t , and On / Off ratio using the semiconductor parameter analyzer “4155C” manufactured by Agilent Technologies in the following manner. Degree μ = 0.13 cm ² / V · s, threshold voltage V _t = −3.5 V, On / Off ratio = 3 × 10 ⁵ .
Moreover, as a result of measuring the electric conductivity of the insulating layer from the overlapping portion of the gate electrode and the source / drain electrode, the electric conductivity was 1 × 10 ⁻¹² S / cm or less.

[Measurement method of the mobility mu, threshold voltage V _t]
The current flowing with respect to the voltage V _d applied between the source electrode and the drain electrode is I _d , the voltage applied to the source electrode and the gate electrode is V _g , the threshold voltage is V _t , and the unit area of the gate insulating layer The operation is expressed by the relationship of the following formula (1) or (2), where C _i is the per-capacitance, L is the distance between the source electrode and the drain electrode, W is the width, and μ is the mobility of the semiconductor layer. Measure the change in I _d for different V _g, find the mobility μ as the slope in the graph plotting I _d ^1/2 and V _g, and calculate the threshold voltage V _t from the I _d intercept of the graph Asked.
When V _d <V _g −V _{t
I d = μC i (W /} L) _{[(V g -V t) V d} - (V d 2/2) ] (1)
When V _d > V _g
I _d = (1/2) μC _i (W / L) (V _g −V _t ) ² (2)

[On / Off ratio]
The voltage V _d applied between the source electrode and the drain electrode is fixed to −30 V, and the voltage V _g applied to the source electrode and the gate electrode flows between the source electrode and the drain electrode when set to −50 V and +30 V. The currents I _d (−50 V) and I _d (+30 V) were measured, and the On / Off ratio was calculated from these ratios I _d (−50 V) / I _d (+30 V).

[Example 2]
The bottom gate / bottom contact type shown in FIG. 1 (A) is the same as in Example 1 except that the polymer B obtained in Synthesis Example 4 is used instead of the polymer A obtained in Synthesis Example 3. A field effect transistor was fabricated.

For the field effect transistor obtained above, the mobility μ, the threshold voltage V _t , and the On / Off ratio were measured in the same manner as in Example 1. As a result, the mobility μ = 0.3 cm ² / V · s, The threshold voltage V _{t was} 5 V, and the On / Off ratio was 2.3 × 10 ⁵ .
Moreover, as a result of measuring the electric conductivity of the insulating layer from the overlapping portion of the gate electrode and the source / drain electrode, the electric conductivity was 1 × 10 ⁻¹² S / cm or less.

[Example 3]
Patterning is performed on an ITO glass plate (Toyo Sangyo Co., Ltd., 2.5 cm x 2.5 cm) using a photoresist ("ZPN1100" manufactured by Nippon Zeon Co., Ltd.) to dissolve 1 wt% iron (II) chloride. Further, unnecessary ITO was etched with 1N aqueous hydrogen chloride solution and washed to form a gate electrode. Then, a 10 wt% N-methylpyrrolidone solution of polymer C obtained in Synthesis Example 5 (pressure-filtered with a 0.2 μm PTFE filter) was spin-coated at a rotation speed of 2000 rpm to form a film. A film (gate insulating layer) having a thickness of 3000 mm was produced. Subsequently, patterning is performed on the gate insulating layer by photolithography (Nagase Chemtex Corp .: positive lift-off resist NPR9700T) to form a source electrode and a drain electrode. As a result, a source electrode and a drain electrode are formed with an interval (L) of 10 μm and a width (W) of 500 μm, and a semiconductor layer is formed thereon by spin-coating Aldrich 3-hexylpolythiophene 1 wt% chloroform solution. Then, the bottom gate / bottom contact type field effect transistor shown in FIG. Note that layer formation and electrode formation were all performed in a nitrogen atmosphere.

The field effect transistor obtained above was measured for mobility μ, threshold voltage V _t , and On / Off ratio in the same manner as in Example 1. As a result, mobility μ = 0.05 cm ² / V · s, The threshold voltage V _{t was} 6 V, and the On / Off ratio was 2.3 × 10 ⁴ .
Moreover, as a result of measuring the electric conductivity of the insulating layer from the overlapping portion of the gate electrode and the source / drain electrode, the electric conductivity was 1 × 10 ⁻¹² S / cm or less.

[Example 4]
[Manufacture of gate electrode]
Cr (thickness 30 nm) was electron beam evaporated on Corning's Eagle 2000 glass wafer using a vacuum deposition apparatus EX-400 manufactured by ULVAC.
Next, resist patterning was performed with Tokyo Ohka's positive resist OFPR-800LB (1500 rpm, spin-coated at 20 seconds, then pre-baked at 80 ° C. for 10 minutes), and 1 minute with Mitsubishi Chemical's Cr etching solution Etching was performed for 20 to 30 seconds.
After completion of the etching, ultrasonic cleaning was performed in order of N, N-dimethylformamide (DMF), acetone, excitran, pure water, and isopropanol (IPA) for 30 minutes, followed by drying at 140 ° C. for 10 minutes.

[Manufacture of gate insulating layer]
A 10 wt% cyclohexanone solution of polymer D (pressure-filtered with a 0.2 μm PTFE filter) was spin-coated on the wafer at 1500 rpm for 120 seconds to produce a 500 nm insulating layer.
This insulating layer was irradiated with 1 J / cm ² of UV, developed with an organic solvent developer for 1 minute 30 seconds, and then rinsed with acetone for 30 seconds to pattern the insulating layer.

[Production of source / drain electrodes]
Cr (thickness 5 nm) and Au (thickness 100 nm) were vacuum-deposited on the entire surface of the insulating layer made of polymer D produced above using a vacuum deposition apparatus EX-400 manufactured by ULVAC.
Next, resist patterning was performed with Tokyo Ohka's positive resist OFPR-800LB (1500 rpm, spin coated at 20 seconds, then pre-baked at 80 ° C. for 10 minutes), and 1 minute with an Au etchant manufactured by Mitsubishi Chemical After etching for 15 seconds with Cr etching solution for 5 seconds, etching was further performed for 5 seconds with Au etching solution.
Then, it was immersed in ammonia water for 1 minute as a neutralization treatment.
Furthermore, after washing in order of DMF, acetone, and IPA, drying was performed at 120 ° C. for 1 hour to produce a polymer gate insulating layer element with source / drain electrodes.

[Semiconductor layer fabrication]
The polymer gate insulating layer element with an electrode prepared above was spin-coated with a 0.7 wt% chloroform solution of the porphyrin compound used in Example 1, and heated at 180 ° C. for 10 minutes to convert the porphyrin compound to tetrabenzoporphyrin. Thus, a bottom-gate / bottom-contact field effect transistor having a semiconductor layer made of tetrabenzoporphyrin and shown in FIG. 1A was manufactured. Note that layer formation and electrode formation were all performed in a nitrogen atmosphere.

The field effect transistor thus obtained having an insulating layer made of polymer D was measured for mobility μ, threshold voltage V _t , and On / Off ratio in the same manner as in Example 1. As a result, mobility μ = 0. It was 0.5 cm ² / V · s, threshold voltage V _t = −1 V, and On / Off ratio = 4.3 × 10 ⁴ .
Moreover, as a result of measuring the electric conductivity of the insulating layer from the overlapping portion of the gate electrode and the source / drain electrode, the electric conductivity was 1 × 10 ⁻¹² S / cm or less.

[Example 5]
[Manufacture of gate electrode]
In the same manner as in Example 4, a gate electrode was produced on the wafer.

[Manufacture of gate insulating layer]
An insulating layer was formed in the same manner as in Example 4 except that polymer A was used instead of polymer D.

[Production of source / drain electrodes]
Au (thickness: 100 nm) was vacuum-deposited on the entire surface of the insulating layer made of polymer A prepared above using a vacuum evaporation apparatus EX-400 manufactured by ULVAC.
Further, in the case of the polymer A, since the thiol group is on the surface, there is an advantage that Cr of the adhesive layer can be removed as compared with Example 4.
Subsequently, resist patterning, etching, neutralization treatment, washing and drying were performed in the same manner as in Example 4 to produce a polymer gate insulating layer element with source / drain electrodes.

[Semiconductor layer fabrication]
A semiconductor layer was fabricated on the polymer gate insulating layer element with electrode fabricated as described above in the same manner as in Example 4 to fabricate the bottom gate / bottom contact field effect transistor shown in FIG. .

The field effect transistor having an insulating layer made of the polymer A was measured for mobility μ, threshold voltage V _t , and On / Off ratio in the same manner as in Example 1. As a result, mobility μ = 1.2 cm ² / V · s, threshold voltage V _t = −4.7 V, and On / Off ratio = 1.3 × 10 ⁵ .
Moreover, as a result of measuring the electric conductivity of the insulating layer from the overlapping portion of the gate electrode and the source / drain electrode, the electric conductivity was 1 × 10 ⁻¹² S / cm or less.

[Comparative Example 1]
Polyvinylphenol (PVP): Aldrich (Mw = 20000 (GPC method)) and poly (melamine-co-formaldehyde) methacrylate (Aldrich) as a crosslinking agent were mixed at a ratio of 4: 1 (weight ratio). The mixture was dissolved in tetrahydrofuran (THF) at a concentration of 5% by weight, and filtered through a 0.45 μm (PTFE) filter. This PVP solution was spread on the substrate in the same manner as in Example 3, and spin coating was performed at 3000 rpm for 120 seconds. Thereafter, a heat treatment was performed at 120 ° C. for 3 minutes, and a transistor element was produced in the same manner as in Example 3 except that a thermally crosslinked PVP film was produced as an insulator layer, and evaluation was performed in the same manner.

The field effect transistor obtained above was measured for mobility μ, threshold voltage V _t , and On / Off ratio in the same manner as in Example 1. As a result, mobility μ = 0.04 cm ² / V · s, The threshold voltage V _{t was} 22 V and the On / Off ratio was 4.7 × 10 ³ .
Moreover, as a result of measuring the electric conductivity of the insulating layer from the overlapping portion of the gate electrode and the source / drain electrode, the electric conductivity was 1 × 10 ⁻¹² S / cm or less.

[Summary]
From Examples 1 to 5 and Comparative Example 1, it can be seen that the element characteristics of the transistor can be improved by including the repeating unit represented by the formula (A) in the gate insulating layer. In addition, since the device characteristics of Examples 1 and 2 are more improved than those of Example 3, the polymer insulator of the present invention contains a crosslinkable vinyl monomer unit and a heat resistant vinyl polymer unit. It was confirmed that the device characteristics were further improved.

  The present invention can be used in any industrial field. For example, the present invention can be used for an element using an insulating layer such as an electronic device. Furthermore, among electronic devices, it is suitable for use in a field effect transistor.

  The field effect transistor can be used as a switching element of a display pixel pixel in an active matrix of a display, for example. This is because the current applied between the source electrode and the drain electrode can be switched by the voltage applied to the gate electrode, and the switch is turned on only when a voltage is applied to or supplied to a certain display element, and the circuit is used for other times. By cutting the line, high-speed and high-contrast display is performed. Examples of the display element to be applied include a liquid crystal display element, a polymer dispersion type liquid crystal display element, an electrophoretic display element, an electroluminescence element, and an electrochromic element.

  In particular, the field effect transistor can be manufactured in a low-temperature process, can use a substrate that cannot withstand high-temperature processing such as plastic and paper, and can be manufactured in a coating or printing process. Also suitable for large area displays. Furthermore, it is advantageous as an element capable of energy saving and a low-cost process as an alternative to the pixel switch element using a silicon semiconductor used in the conventional active matrix.

  Further, by integrating transistors, a digital element or an analog element can be realized. Examples of these include logic circuits such as AND, OR, NAND, NOT, memory elements, oscillation elements, amplification elements, and the like. Furthermore, an IC card, an IC tag, etc. can also be produced by combining these.

  In addition, an organic semiconductor may be applied to a sensor by utilizing the fact that the characteristics of the organic semiconductor change greatly due to external stimuli such as gas, chemical substance, and temperature. For example, it is possible to detect the chemical substance contained in it qualitatively or quantitatively by measuring the quantity which changes with contact with gas or liquid.

(A)-(D) are all the longitudinal cross-sectional views which show typically the typical structure of the field effect transistor as one Embodiment of this invention. 3 is a diagram illustrating a mass spectrometry spectrum of p-vinylbenzenethiol obtained in Synthesis Example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Support substrate 2 Gate electrode 3 Gate insulating layer (insulating layer)
4 Semiconductor layer 5 Source electrode 6 Drain electrode

Claims (13)

An insulating layer comprising a polymer insulator containing at least a repeating unit represented by the following formula (A).

(In the formula (A),
R ^a represents a direct bond or any linking group,
Ar represents an optionally substituted divalent aromatic group,
R ^b represents a hydrogen atom, a fluorine atom or a monovalent organic group. ) The insulating layer according to claim 1, wherein R ^a is a direct bond.   The insulating layer according to claim 1, wherein Ar is a hydrocarbon aromatic ring that may be substituted. The insulating layer according to any one of claims 1 to 3, wherein R ^b is a hydrogen atom or a linear or branched hydrocarbon group. The insulating layer according to any one of claims 1 to 4, wherein the polymer insulator includes a repeating unit derived from at least vinylthiophenol and / or a vinylthiophenol derivative.   The insulating layer according to claim 1, wherein the polymer insulator includes a repeating unit derived from a crosslinkable vinyl monomer.   The insulating layer according to any one of claims 1 to 6, wherein the polymer insulator includes a repeating unit derived from a heat-resistant vinyl monomer. The insulating layer according to any one of claims 1 to 7, wherein the electric conductivity is 1 x ^10-12 S / cm or less. An electronic device comprising the insulating layer according to claim 1. A field effect transistor comprising the insulating layer according to claim 1.   The field effect transistor according to claim 10, comprising a semiconductor layer containing porphyrin, a source electrode, a drain electrode, and a gate electrode. A polyvinyl thiophenol comprising at least a repeating unit derived from vinyl thiophenol and / or a vinyl thiophenol derivative and a repeating unit derived from a crosslinkable vinyl monomer. A polyvinyl thiophenol comprising at least a repeating unit derived from vinyl thiophenol and / or a vinyl thiophenol derivative and a repeating unit derived from a heat-resistant vinyl monomer.

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