JP2000109530A - Aromatic polycarbodiimide and sheet thereof - Google Patents

Abstract

(57) [Abstract] [Problem] It has high solubility in organic solvents and good processability.
In addition, a polycarbodiimide having excellent heat resistance, moisture resistance and low dielectric constant is obtained. The present invention provides the following formula (I): (Wherein, n is an integer of 2 to 300, m is 0 or 1, A is a divalent organic group having 4 or less carbon atoms, and Ph is a phenyl group). Polycarbodiimide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to novel aromatic polycarbodiimides. The aromatic polycarbodiimide of the present invention can be used as a sheet (film), adhesive, or molded product having various excellent properties such as high heat resistance, low moisture absorption, and low dielectric constant.

[0002] As the aromatic polycarbodiimide, those obtained by polymerizing diphenylmethane diisocyanate (MDI) or tolylene diisocyanate (TDI) as a monomer have been known. Such polycarbodiimides are used as flame-resistant films and heat-resistant adhesives due to their excellent heat resistance.

[0003]

Objects and Summary of the Invention These polycarbodiimide films have heat resistance in that they do not generate volatile gases or decomposed monomers even when exposed to a high temperature of 400 ° C. or higher, but have low moisture resistance or a temperature of 200 ° C. or higher. When heat-treated, there is no self-holding property, the material becomes brittle, and cannot be put to practical use. Further, the solubility in organic solvents is poor and the processability is low.

[0004] The present inventors have intensively studied various starting monomers and aromatic carbodiimide polymers in order to solve such disadvantages of the conventional polycarbodiimide. As a result, they have found that the above-mentioned problems can be solved by the following polycarbodiimide having a novel skeleton, and have completed the present invention.

That is, the present invention provides the following formula (I):

Embedded image (Wherein, n is an integer of 2 to 300, m is 0 or 1, A is a divalent organic group having 4 or less carbon atoms, and Ph is a phenyl group). A polycarbodiimide is provided.

[0006] This polymer is a novel polymer compound, has excellent solubility and very high heat resistance, and also has excellent adhesiveness, low-temperature processability and moisture resistance.

The following formula (II) related to the polycarbodiimide of the present invention and filed by the applicant of the present application is given below:

Embedded image (In the formula, n represents an integer, and the substitution positions of the two phenoxy groups bonded to the central benzene ring are 1,3- or 1,4-
It is a union. The aromatic polycarbodiimide represented by the formula (1) is known (JP-A-9-235341). However, there is no report of a polycarbodiimide having a substituent on the central benzene ring of the main chain as in the present invention. It is presumed that the polycarbodiimide of the present invention has a further improvement in solubility and heat resistance as compared with the case where there is no substituent, by introducing a substituent on the benzene ring at the center of the main chain.

[0008]

DETAILED DESCRIPTION OF THE INVENTION The polycarbodiimides of the present invention
The following formula (III) as a monomer:

Embedded image (Wherein m, A and Ph are the same as described above), and can be obtained by polymerizing this in the presence of a phosphorus-based catalyst by a method known per se.

In the above formula, A is a divalent organic group having 4 or less carbon atoms, such as a carbonyl group, a vinylene group, a propenylene group, a methylene group, an ethylene group, an ethylidene group, a trimethylene group, a propylene group, and an isopropylidene group. And a tetramethylene group. Of these, carbonyl, vinylene, propenylene, methylene, ethylene, ethylidene, and isopropylidene are particularly preferred. Ph is a phenyl group. In addition, the polymerization degree n is 2-300. If n is larger than this, the storage stability of the polymer solution may deteriorate, which is not preferable.

Accordingly, the diisocyanate monomer which is a raw material of the polycarbodiimide of the present invention is specifically 2-phenyl-1,4-bis (4-isocyanatophenoxy) benzene, 2-benzyl-1,4-bis ( 4-
Isocyanatophenoxy) benzene, 2-phenethyl-1,4-bis (4-isocyanatophenoxy) benzene, 2-styryl-1,4-bis (4-isocyanatophenoxy) benzene, 2-cinnamyl-1,4- Screw (4
Isocyanatophenoxy) benzene, 2-benzoyl-1,4-bis (4-isocyanatophenxy) benzene, 2- (α, α-dimethylbenzyl) -1,4-bis (4
-Isocyanatophenoxy) benzene, 2- (α-methylbenzyl) -1,4-bis (4-isocyanatophenoxy) benzene, and substituted position isomers thereof.

With respect to the diisocyanate of the formula (III), which is a monomer of the polycarbodiimide of the present invention, a diisocyanate represented by the following formula (IV) is known.
(JP-A-9-188660) does not disclose the monomer used in the present invention.

[0012]

Embedded image (Wherein, R ₁ , R ₂ and R ₃ are each independently a lower alkyl or halogen atom having 1 to 4 carbon atoms;
It is represented by an integer of ~ 4. )

Another method for producing the polycarbodiimide of the present invention is represented by the following formula (V):

Embedded image (Wherein m, A and Ph are the same as described above), the compound of formula (III) is obtained by diisocyanating the aromatic diamine itself by a known method, and then polymerized. Good.

(Production of diisocyanate from diamine) As a method for obtaining a diisocyanate from such a diamine, there is a method in which phosgene, diphenyl carbonate, or carbonyldiimidazole is allowed to act. Further, as another method, a dicarbamate is synthesized by reacting a halogenated alkyl formate or a halogenated aryl formate on a diamine compound, and is diisocyanated using chlorosilane as an activating reagent (G. Greber. et. al., Angew. Chem. Int. E
d., Vol. 17, No. 12, 941 (1968)) or diisocyanation using catechol borane (VLKValli.et.a
L., J. Org. Chem., Vol. 60, 257 (1995)), and these methods are more preferable in terms of yield and safety.

First, a dicarbamate is produced by reacting a corresponding diamine compound with methyl chloroformate, ethyl chloroformate, phenyl chloroformate, p-nitrophenyl chloroformate or the like. Of these, phenyl chloroformate or p-nitrophenyl chloroformate is suitable for smoothly proceeding with isocyanation. Since p-nitrophenyl chloroformate has high activity and may cause a side reaction, phenyl chloroformate is most preferred. These halogenated formates may be used alone or in combination of two or more. The used amount of the halogenated formate is preferably 1.5 to 3.4 times the number of moles of the diamine.
8-3.0 times is more preferable. If the amount used is smaller than this, unreacted diamine remains in the system, which causes a side reaction such as the generation of isocyanate and urea, which is not preferable. On the other hand, if it is larger than the above range, it is difficult to remove from the system after the completion of the reaction or a side reaction is undesirably caused.

The solvent used in these reactions may be any solvent that can dissolve the diamine. For example, ether compounds such as tetrahydrofuran (THF), dioxane and diethyl ether; ketone compounds such as acetone, methyl ethyl ketone and methyl isobutyl ketone; ester compounds such as ethyl acetate; aromatic hydrocarbons such as toluene, xylene and benzene Halogenated hydrocarbons such as chloroform, methylene chloride, and tetrachloroethylene. These solvents may be used alone or as a mixture of two or more.

The diamine concentration in the reaction mixture is from 1 to 50.
%, Preferably 5-40%, optimally 10-30%. If the concentration is too low, the reaction requires time, which is not practical. If the concentration is too high, an undesired side reaction may be caused or control of the reaction may be difficult.

The reaction temperature is between -40 and 100 ° C, preferably between -20 and 80 ° C, most preferably between 0 and 60 ° C. When the reaction temperature is lower than −40 ° C., the reaction hardly proceeds, which is not practical. If the temperature is higher than 100 ° C., a side reaction such as condensation may occur.

As a base for trapping hydrogen chloride generated by the reaction, any base can be used as long as it dissolves in the solvent used and does not inhibit the reaction, and both an organic base and an inorganic base can be used. Organic bases are preferred because they are easily soluble in solvents, and especially triethylamine, sodium hydroxide, pyridine, 1,8-diazabicyclo [5.4.0] -7-undecene, collidine, picoline, lutidine because they do not inhibit the reaction. Tertiary amines such as are preferred. The amount of the base used is preferably 1.5 to 3.4 times the number of moles of the diamine used, and more preferably 1.8 to 3.0.

In order to purify the obtained dicarbamate, a conventionally known method such as recrystallization or column can be used. Further, distillation may be performed as necessary.

In order to convert the dicarbamate into a diisocyanate using an organic silicon halide compound, the molar amount of the dicarbamate is 1.5 to 3.4 times, preferably 1.8 to 3.0 times. Is thermally decomposed using the above organic silicon halide compound as a catalyst. If the amount of the catalyst is less than this range, the reaction may not proceed completely. Also,
If it is larger than this range, the polymerization may proceed too much and the molecular weight may become too large. In addition, there is a concern that it is difficult to remove unreacted substances.

As the organic silicon halide compound, specifically, chlorosilanes such as trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, triethylchlorosilane, trimethoxychlorosilane, and tetrachlorosilane are preferable. Trimethylchlorosilane is preferred.

The solvent used may be any one capable of dissolving or suspending the dicarbamate, and any of the solvents used for the above-mentioned carbamate formation may be used. These solvents may be used alone or as a mixture of two or more. In some cases, the reaction temperature may be changed by substituting part or all of the reaction during the reaction.

The reaction temperature is 0 to 150 ° C., preferably 20
-130 ° C, most preferably 40-110 ° C. When the temperature is lower than 0 ° C., the reaction hardly proceeds, and when the temperature is higher than 150 ° C., it is difficult to select a solvent.

As a base for trapping hydrogen chloride generated during the reaction, the same base as in the above-mentioned carbamate formation may be used, and the amount used is also the same.

After the reaction, the obtained diisocyanate monomer may be purified by a known method such as column or distillation, or may be used as it is after removing excess reaction reagents and solvent.

(Production of polycarbodiimide from diisocyanate) In order to produce the polycarbodiimide of the present invention, the diisocyanate monomer of the formula (III) may be used alone, as long as the properties of the polycarbodiimide of the present invention are not impaired. And other organic diisocyanates such as 4,
4'-diphenylmethane diisocyanate, 2,6-tolylene diisocyanate, 2,4-tolylene diisocyanate, 1-methoxyphenyl-2,4-diisocyanate, 3,3'-dimethoxy-4,4'-diphenylmethane diisocyanate, 4'-diphenyl ether diisocyanate, 3,3'-dimethyl-4,4'-diphenyl ether diisocyanate, o-tolylene diisocyanate, 2,2-bis [4- (4-isocyanatophenoxy) phenyl] hexafluoropropane, 2,2 -Screw
It may be copolymerized with [4- (4-isocyanatophenoxy) phenyl] propane or the like.

The copolymerization ratio is from 1 to 90 mol%, more preferably from 1 to 70 mol%, and most preferably from 1 to 50 mol%, based on the diisocyanate monomer represented by the formula (III). If the copolymerization ratio exceeds 90 mol%, the properties of the polycarbodiimide of the present invention may be lost. Moreover, 1/100 to 100 with respect to the polycarbodiimide of the present invention.
Other polycarbodiimides may be mixed and used in a varnish state at a ratio of / 1.

The polymerization temperature is preferably from 40 to 150 ° C.,
0-140 degreeC is more preferable. When the reaction temperature is lower than 40 ° C., the reaction time becomes too long and is not practical. Also 150
If the reaction temperature exceeds ℃, it is difficult to select a solvent.

The concentration of diisocyanate monomer in the synthesis of polycarbodiimide is 5 to 70% by weight (hereinafter simply referred to as%
), Preferably 10-60%, most preferably 1
5% to 50%. If the monomer concentration is lower than 5%, carbodiimidization may not proceed. If it exceeds 70%, control of the reaction may be difficult.

The organic solvent used in the synthesis of the polycarbodiimide and for the polycarbodiimide solution may be a conventionally known organic solvent. Specifically, tetrachloroethylene, 1,
Halogenated hydrocarbons such as 2-dichloroethane, chloroform and dichloromethane; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; cyclic ether solvents such as tetrahydrofuran and dioxane; aromatic hydrocarbon solvents such as toluene and xylene Is mentioned. These may be used alone or in combination of two or more.

As the catalyst used for the carbodiimidization, any known phosphorus-based catalyst is suitably used.
Phenyl-2-phospholene-1-oxide, 3-methyl-2-phospholene-1-oxide, 1-ethyl-2-phospholene-1-oxide, 3-methyl-1-phenyl-
2-phospholene-1-oxide, or 3-
Phosphorene oxides such as phosphorene isomers are included.

The above-mentioned diamine is carbamate,
In diisocyanation and carbodiimidization, isolation and purification may be performed in each step, and the steps may be performed in a stepwise manner, or these steps may be continuously performed in a single reaction vessel as a series of reactions.

The terminal blocking treatment may be carried out by adding a monoisocyanate at any of the last stage, the middle stage and the initial stage of the polymerization reaction or over the whole. As such a monoisocyanate, phenyl isocyanate, p-nitrophenyl isocyanate, p- and m-tolyl isocyanate, p-formylphenyl isocyanate, p-isopropylphenyl isocyanate and the like can be used. The polycarbodiimide solution thus obtained is excellent in storage stability of the solution.

After the completion of the reaction, the reaction solution may be poured into a poor solvent such as methanol, ethanol, hexane, or isopropyl alcohol to precipitate polycarbodiimide as a precipitate to remove unreacted monomers and catalyst. To prepare a solution of polycarbodiimide, the polymer precipitated as a precipitate is washed and dried by a predetermined operation,
Dissolve again in the organic solvent. By performing such an operation, the solution stability of the polycarbodiimide can be improved.

Further, the by-products contained in the polymer solution may be purified by adsorbing them on a suitable adsorbent or the like. As the adsorbent, for example, alumina gel, silica gel, activated carbon, zeolite, activated magnesium oxide, activated bauxite, flour earth, activated clay, molecular sieve carbon, or the like can be used alone or in combination.

In the polycarbodiimide of the present invention, n in the formula (I) is an integer of 2 to 300, preferably 4 to 1
It is an integer of 00. If the molecular weight of the polycarbodiimide is larger than this, gelation occurs easily within several minutes to several hours even when left at room temperature, which is not practically preferable. On the other hand, if the molecular weight is lower than this, the reliability of the coating film is lacking, which is not preferable.

(Production of Film and Adhesive Sheet) The polycarbodiimide film (or sheet) of the present invention is formed from a polycarbodiimide varnish to an appropriate thickness using a known method (casting, spin coating, roll coating, etc.). It is obtained by doing. This film is usually dried at a temperature necessary for removing the solvent, and the coating temperature is, for example, 20 to 350 ° C., preferably 50 to 30 ° C. so that the curing reaction is not greatly advanced.
0 ° C, most preferably 70-250 ° C. If the drying temperature is lower than 20 ° C., the solvent remains in the film, and the reliability of the film becomes poor, which is not preferable. On the other hand, when the drying temperature is higher than 350 ° C., thermal curing of the film tends to proceed.

The polycarbodiimide resin composition of the present invention may contain a fine inorganic filler as long as the processability and heat resistance are not impaired. Various additives such as a smoothing agent, a leveling agent, and a defoaming agent for improving surface smoothness may be added as necessary.

The molded product obtained by molding the polymer of the present invention into a film can be used as a heat-resistant adhesive sheet. The thickness of the film or sheet that can be formed into an adhesive sheet is generally 1 to 200 μm,
The present invention is not limited to this, and can be appropriately selected according to the purpose. Also, the shape and size of the sheet can be appropriately determined according to the adherend such as a lead frame or a semiconductor chip.

In the production of the adhesive sheet, for example, aluminum, copper, silver, gold, nickel, chromium, and lead are used in order to impart conductivity, improve thermal conductivity, adjust elastic modulus, and particularly increase elastic modulus. , Tin, zinc, palladium, metals such as solder, or alloys, alumina, silica, magnesia,
One or more kinds of various inorganic powders made of ceramics such as silicon nitride and other carbon may be blended as necessary.

Further, these films may be formed on a support to form an adhesive sheet. In order to manufacture the adhesive sheet having such a configuration, a varnish may be applied on the support, or a film may be formed in advance, and the film may be laminated by a press or the like.

The support used here is a metal foil,
Insulating films and the like can be mentioned. As the metal foil, any of aluminum, copper, silver, gold, nickel, indium, chromium, lead, tin, zinc, palladium and the like may be used, and these may be used alone or as an alloy. As the insulating film, any film having heat resistance or chemical resistance, such as polyimide, polyester, or polyethylene terephthalate, can be used.

Further, the metal foil and the insulating film may be used alone, or a two-layer base material such as a metal foil / insulating film may be used in which two or more layers are laminated. Examples of such a two-layer substrate include a copper / polyimide two-layer substrate.

The sheet adhesive of the present invention is hardened by heat treatment to exhibit a strong adhesive force, and becomes a cured product having low hygroscopicity. In order to perform the heat treatment, for example, an appropriate method such as a heater, ultrasonic waves, or ultraviolet rays may be used. Therefore, the adhesive sheet of the present invention is preferable for the bonding treatment of various materials, and in particular, is required to have a highly reliable fixing treatment, and is therefore required to have low moisture absorption. It is preferable for fixing parts. The adhesive sheet of the present invention is excellent in that it has low hygroscopicity, is flexible and easy to handle, has good adhesiveness to semiconductor elements, and has good storage stability.

(Use) The polycarbodiimide resin thus produced can be used as an adhesive for electronic parts by utilizing its heat resistance.

[0047]

Next, the present invention will be described more specifically with reference to examples and comparative examples. All reactions were performed under a nitrogen stream. In addition, the characteristic of the obtained polycarbodiimide was measured as follows.

IR was measured using FT / IR-230 manufactured by JEOL.

The thermosetting temperature was measured using DSC-200 (manufactured by Seiko Denshi Kogyo Co., Ltd.), and the exothermic peak of trimerization was defined as the thermosetting temperature.

HLC8120 (manufactured by Tosoh Corporation) as a number average molecular weight apparatus, and GMH
_The measurement was performed using _HR-H + GMH _HR-H + G2000H _HR (manufactured by Tosoh Corporation) using tetrahydrofuran as a developing solvent.

Adhesion Strength A 180 ° peel strength was measured using Shimadzu Autograph AGS-100D.

The modulus of elasticity (E ') and the glass transition temperature (Tg) were measured using DMS210 (manufactured by Seiko Instruments Inc.).

Example 1 2-Phenyl-1,4-bis (4-aminophenoxy) was placed in a 500 mL four-necked flask equipped with a stirrer, a dropping funnel, a reflux condenser, and a thermometer.
Benzene (20 g, 54.28 mol), triethylamine (10.
99 g, 108.56 mol) and 156.5 g of toluene. The flask was cooled in an ice bath, phenyl chloroformate (17.00 g, 108.56 mol) was placed in the dropping funnel and added dropwise over 1 minute. Thereafter, the mixture was stirred at room temperature for 120 minutes.

After confirming the formation of carbamate by IR,
Trimethylchlorosilane (11.79 g, 108.56 mol), triethylamine (10.99 g, 108.56 mol), carbodiimidation catalyst (3-methyl-1-phenyl-2-phospholene-1-oxide) (521.6 mg, 2.714 mmol) The mixture was stirred at 60 ° C. for 1 hour and then at 80 ° C. for 4 hours to perform isocyanation and polymerization.

The carbodiimidization was confirmed by IR spectrum (FIG. 1), and the formed triethylamine hydrochloride was removed by filtration to obtain a varnish. The number average molecular weight (Mn) of this polycarbodiimide was 2350 (n = 6).

The storage stability of the above varnish is 10 days or more, and the varnish is cast on a glass plate at 90 ° C.
For 30 minutes and further at 250 ° C. for 30 minutes to obtain a flexible film. When the thermal properties of the obtained film were evaluated, the thermosetting temperature was 330 ° C., the glass transition temperature was 203 ° C., and the elastic modulus at room temperature was 3.0 GPa.

The varnish was reprecipitated with isopropyl alcohol, and the precipitated solid was collected and dried, and the powder obtained was toluene, tetrahydrofuran, cyclohexanone,
It could be redissolved in common organic solvents such as chloroform.

Example 2 2- (α, α-
A polycarbodiimide was synthesized in the same manner as in Example 1 except that dimethylbenzyl) -1,4-bis (4-aminophenoxy) benzene was used.

The varnish was reprecipitated with isopropyl alcohol, and the precipitated solid was collected and dried, and had a number average molecular weight of 3,5.
A powder of 00 (n = 8) polycarbodiimide was obtained.

The storage stability of the above varnish is 10 days or more, and the varnish is cast on a glass plate at 90 ° C.
For 30 minutes and further at 250 ° C. for 30 minutes to obtain a flexible film. When the thermal properties of the obtained film were evaluated, the thermosetting temperature was 330 ° C., the glass transition temperature was 190 ° C., and the elastic modulus at room temperature was 2.5 GPa.
Met.

Further, the varnish was reprecipitated with isopropyl alcohol, and the precipitated solid was collected and dried, and the powder obtained was toluene, tetrahydrofuran, cyclohexanone,
It could be redissolved in common organic solvents such as chloroform.

Comparative Example 1 1,4-bis as diamine
A polycarbodiimide was synthesized in the same manner as in Example 1 except that (4-aminophenoxy) benzene was used.

The varnish was reprecipitated with isopropyl alcohol, and the precipitated solid was collected and dried, and the number average molecular weight was 1,9.
A powder of 00 (n = 6) polycarbodiimide was obtained. The powder was soluble at low temperatures in polar solvents such as tetrahydrofuran, but was insoluble in non-polar solvents such as toluene.

Comparative Example 2 5 g (28.7 mmol) of a mixture of 2,4-tolylene diisocyanate / 2,6-tolylene diisocyanate (mixing ratio 90:10) was added to tetrahydrofuran 2
In 0 g of carbodiimidation catalyst (3-methyl-1-phenyl-2-phospholene-1-oxide) 43 mg (0.22 mmol)
The mixture was stirred at 60 ° C. for 15 hours together with l) to obtain a polycarbodiimide solution. The number average molecular weight of this polymer is 6,70
0 (n = 52).

Casting the varnish on a glass plate,
Drying at 90 ° C. for 30 minutes and then at 250 ° C. for 30 minutes gave a black, very brittle film. When the thermal properties of this film were evaluated, the thermosetting temperature was 300
° C, the glass transition temperature was 227 ° C, and the elastic modulus at room temperature was 3.9 GPa.

[Examples 3 and 4 and Comparative Example 3]
The polycarbodiimide films obtained in Comparative Example 2 and Comparative Example 2 were each placed on a copper foil, sandwiched between 42 alloy plates, and pressed by an electric heat press at 250 ° C. and a pressure of 50 kg / cm ² for 1 second to be bonded. The measurement results of the peel strength and solder heat resistance at this time are shown in the table.

[0067]

[Table 1] ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Polycarbodiimide peel strength (g / cm) Solder durability (260 ° C x 10 seconds) 実 施 Example 1 1200 No blister Example 2 1400 No swelling 比較 Comparative Example 2 50 Swelling ━━━ ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

[0068]

The polycarbodiimide of the present invention has high solubility in organic solvents, good processability, and excellent heat resistance.
It exhibits moisture resistance and can be used as a heat-resistant coating material in a soldering step in the production of electronic components.

[Brief description of the drawings]

FIG. 1 is an infrared absorption spectrum of the polycarbodiimide obtained in Example 1.

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[Procedure amendment]

[Submission Date] November 30, 1998 (1998.11.
30)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0053

[Correction method] Change

[Correction contents]

Example 1 2-Phenyl-1,4-bis (4-aminophenoxy) was placed in a 500 mL four-necked flask equipped with a stirrer, a dropping funnel, a reflux condenser, and a thermometer.
Benzene (20 g, 54.28 mmol ), triethylamine (1
0.99 g (108.56 mmol ) and 156.5 g of toluene. The flask was cooled in an ice bath, phenyl chloroformate (17.00 g, 108.56 mmol ) was added to the dropping funnel, and
Dropped over minutes. Thereafter, the mixture was stirred at room temperature for 120 minutes.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0054

[Correction method] Change

[Correction contents]

After confirming the formation of carbamate by IR,
Trimethylchlorosilane (11.79 g, 108.56 mmol ),
Triethylamine (10.99 g, 108.56 mmol ), carbodiimidation catalyst (3-methyl-1-phenyl-2-phospholene-1-oxide) (521.6 mg, 2.714 mmol) were charged, and the mixture was added at 60 ° C. for 1 hour, followed by 80 hours. The mixture was stirred at 4 ° C. for 4 hours to carry out isocyanation and polymerization.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0063

[Correction method] Change

[Correction contents]

The varnish was reprecipitated with isopropyl alcohol, and the precipitated solid was collected and dried, and the number average molecular weight was 1,9.
A powder of 00 (n = 6) polycarbodiimide was obtained. This powder was soluble at low concentrations in polar solvents such as tetrahydrofuran, but was insoluble in non-polar solvents such as toluene.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shu Mochizuki 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Michio Satsuma 1-1-2 Shimohozumi, Ibaraki-shi, Osaka F-term in Nitto Denko Corporation (reference) 4F071 AA60A AH13 BC01 BC02 CB02 CC02 CC03 CC04 4J002 CM051 EA056 EB026 ED026 EE036 EH036 EL066 EL106 FD206 GJ01 HA05 4J034 AA05 HA07 HC08 HC12 HC63 HC65 HC71 RA

Claims (3)

[Claims] 1. The following formula (I): (Wherein, n is an integer of 2 to 300, m is 0 or 1, A is a divalent organic group having 4 or less carbon atoms, and Ph is a phenyl group). Polycarbodiimide. 2. A polycarbodiimide solution obtained by dissolving the aromatic polycarbodiimide according to claim 1 in an organic solvent. 3. A polycarbodiimide sheet comprising the aromatic polycarbodiimide of claim 1.