JP2003128714A - Method for producing partially polymerized acrylic polymer composition, partially polymerized acrylic polymer composition produced by the production method and adhesive composition produced by ultraviolet polymerization of the composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for the production of a partially polymerized acrylic polymer composition enabling easy control of the removal of heat in the reaction system even by carrying out the thermal radical polymerization of an acrylic monomer in the absence of solvent using a simple polymerization apparatus. SOLUTION: The method for the production of a partially polymerized acrylic polymer composition comprises the radical polymerization of an acrylic monomer by heating the monomer without using a solvent in the presence of a tackifier resin soluble in the acrylic monomer and having little inhibiting action on the polymerization until the conversion of the acrylic monomer reaches 15-80 wt.%.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a specific acrylic partial polymer composition, an acrylic partial polymer composition obtained by the production method, and a pressure-sensitive adhesive composition obtained by UV-polymerizing the composition. Regarding things. Such an acrylic partial polymer composition of the present invention or a pressure-sensitive adhesive composition containing the acrylic partial polymer composition, a label,
It can be suitably used as various pressure-sensitive adhesives applied to sheets, tapes, etc., particularly as UV-polymerizable pressure-sensitive adhesives.

[0002]

2. Description of the Related Art Generally, pressure sensitive adhesives can be classified into solvent type, emulsion type, hot melt type and the like. Solvent-based pressure-sensitive adhesives are prepared by dissolving components such as natural rubber, synthetic rubber, base polymers such as acrylic polymers, tackifying resins, plasticizers, etc. in an organic solvent, applying the solution to a substrate, and then drying the solvent. Is used. However, solvent-based adhesives have problems in disaster prevention such as fire, pollution, working environment, and health such as so-called sick house syndrome due to the organic solvent used as a component. Tend to be shunned. On the other hand, acrylic emulsion type adhesives, suspension polymerization type adhesives, hot melt type adhesives, etc. have solved many of the above problems, but the former two require the drying of water. It is unsatisfactory in terms of energy, wastewater treatment and other environmental aspects, and water resistance, and the latter is not sufficiently satisfactory in terms of workability of coating equipment and heat resistance.

In order to improve the above-mentioned drawbacks of the pressure-sensitive adhesive, a UV-polymerizable acrylic pressure-sensitive adhesive in which a pressure-sensitive adhesive component is polymerized and cross-linked by a chemical reaction after coating is essentially an organic solvent.
It is widely used because it does not require the use of water or a drying process and has excellent adhesive properties, heat resistance, water resistance, weather resistance and other properties.

This UV-polymerizable acrylic pressure-sensitive adhesive is prepared by first preparing an acrylic partial polymer composition (so-called polymer syrup) having a coatable viscosity, coating it on a substrate, and then exposing it to UV rays. When it is cured, it functions as an adhesive. Various methods have been proposed for producing this acrylic partial polymer composition. For example, a method of bulk polymerizing an acrylic monomer with a thermal decomposition type polymerization initiator, a method of polymerizing in a single-screw or twin-screw extruder, a method of polymerizing by irradiating a batch type reaction container with ultraviolet rays. And so on.

However, when bulk polymerization is carried out on an industrial scale, it is difficult to remove the heat of polymerization because the viscosity in the reaction system rapidly increases as the polymerization of the acrylic monomer progresses. In order to solve this, use of a low-temperature active thermal decomposition type polymerization initiator, cooling by charging an acrylic monomer into the reaction system, etc. have been proposed, but it is not satisfactory in terms of thermal control. Absent.

A method for polymerizing in a single-screw or twin-screw extruder and a method for polymerizing by irradiating a batch type reaction vessel with ultraviolet rays are obtained because very special apparatuses are used. There is a disadvantage that the cost of the acrylic partial polymer becomes high.

[0007]

SUMMARY OF THE INVENTION The present invention is to solve the above problems. That is, even if the acrylic monomer is radically polymerized by heat in the absence of a solvent using a simple polymerization facility, a production method for obtaining an acrylic partially polymerized composition capable of easily controlling the heat removal in the reaction system. To provide,
It is an object of the present invention to provide the acrylic partial polymerization composition, and further to provide a UV-polymerizable acrylic pressure-sensitive adhesive containing the acrylic partial polymerization composition.

[0008]

The inventor of the present invention has made extensive studies in order to solve the above-mentioned problems of the prior art. That is, in consideration of energy saving, work environment hygiene, economical efficiency, etc., while paying attention to a method of bulk polymerization (radical polymerization by heating in the absence of a solvent) of an acrylic monomer using a simple polymerization apparatus. , Heat removal control in the polymerization reaction system, as a result of diligent study in view of the preparation efficiency and adhesive properties of the target adhesive, by performing the polymerization reaction in the presence of a specific tackifying resin, the conventional technique The present invention has been completed by finding that it is possible to provide an acrylic partial polymerization composition and an ultraviolet polymerization type acrylic pressure-sensitive adhesive that can solve the above problem.

That is, according to the present invention, radical polymerization is carried out by heating an acrylic monomer in the absence of a solvent in the presence of a tackifying resin that is compatible with the acrylic monomer and has no polymerization inhibitory property. A method for producing an acrylic partial polymer composition, characterized in that the polymerization rate of the system monomer is 15 to 80% by weight; the acrylic partial polymer composition obtained by the production method; and the composition. The present invention relates to a pressure-sensitive adhesive composition obtained by ultraviolet polymerization.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The acrylic monomer used in the present invention is not particularly limited, and those generally used for acrylic pressure-sensitive adhesives can be used. Examples of such acrylic monomers include methyl (meth) acrylate,
(Meth) acrylic acid alkyl ester such as ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate; methoxyethyl (meth) acrylate ,
Alkoxyalkyl (meth) acrylates such as ethoxyethyl (meth) acrylate, propoxyethyl (meth) acrylate; phenyl (meth) acrylate, (meth)
(Meth) acrylic acid aryl ester such as benzyl acrylate; (meth) acrylic acid; (meth) acrylic acid metal salt; ethylene glycol di (meth) acrylic acid ester, diethylene glycol di (meth) acrylic acid ester, etc. Di (meth) acrylic acid ester of (poly) alkylene glycol; trimethylolpropane poly (meth) acrylic acid such as tri (meth) acrylic acid ester
Examples thereof include acrylic acid ester. Furthermore, to the extent that the performance of the acrylic pressure-sensitive adhesive composition is not impaired, an epoxy group-containing monomer such as (meth) acrylic acid glycidyl ether, a hydroxyl group-containing monomer such as 2-hydroxyethyl (meth) acrylate, Amide group-containing monomers such as (meth) acrylamide, organosilicon group-containing vinyl compound monomers such as vinyltrimethoxysilane, unsaturated carboxylic acids such as itaconic acid, crotonic acid, maleic acid and fumaric acid, Examples thereof include copolymerizable monomers having an unsaturated double bond such as vinyl acetate and styrene.

In the present invention, it is necessary to use, as the tackifying resin coexisting in the polymerization system, a resin having good compatibility with the acrylic monomer and little polymerization inhibition. Examples of the tackifying resin include hydrides of alcohol-modified dicyclopentadiene (hereinafter, dicyclopentadiene is abbreviated as DCPD) resins, rosins containing 40% by weight or more of tetrahydroabietic acid type skeleton, and rosin derivatives. These may be used alone or in appropriate combination of two or more. Further, the UV-polymerizable pressure-sensitive adhesive using the acrylic partial polymer composition obtained by adding these tackifying resins can greatly improve the adhesive force to the polyolefin or the like which is difficult to adhere to. . In addition, as long as compatibility with an acrylic monomer and polymerization inhibition of an acrylic monomer are not significantly impaired, it does not hinder the combined use of tackifying resins other than these.

Alcohol-modified D among the tackifying resins
The hydride of CPD resin is obtained by hydrogenating alcohol-modified DCPD resin. Alcohol modified D
The hydride of CPD resin is disclosed in JP-A-2000-248150.
No. 2001-173323 and the like, and can be obtained by a known method.

The hydride of the alcohol-modified DCPD resin obtained has a hydroxyl value of 10 mgKOH / g or more and 250 mgKOH / g or less, preferably 30 mgKOH / g or more and 220 mgKO, measured according to JIS K 0070.
H / g or less, more preferably 50 mg KOH / g or more 2
It is not more than 00 mgKOH / g. Hydroxyl value is 10mgK
It is preferable that the content be OH / g or more and 250 mgKOH / g or less because the compatibility with the acrylic monomer becomes good.

The tackifying resin has a softening point measured according to JIS K 2531 of 50 ° C or higher and 160 ° C or lower, preferably 60 ° C or higher and 150 ° C or lower, and more preferably 70 ° C or higher and 140 ° C or lower. When the softening point is 50 ° C. or higher and 160 ° C. or lower, compatibility with an acrylic monomer and workability during hydrogenated resin production are improved, which is preferable. Further, the tackifying resin has a color tone of 3 Gardner or less, preferably 2 Gardner or less, and more preferably 1 Gardner or less. A color tone of 3 Gardner or less is preferable because the adhesive composition has a good appearance.

The hydride of the alcohol-modified DCPD resin has a number average molecular weight of 100 or more and 1000 or less, preferably 200 or more and 800 or less, more preferably 250 or more 6
It is 00 or less. When the number average molecular weight is 100 or more and 1000 or less, workability is improved, which is preferable.

The tetrahydroabietic acid-type skeleton of a rosin and / or a derivative thereof containing 40% by weight or more of the component of the tetrahydroabietic acid-type skeleton suitable for the tackifying resin used in the present invention means the cyclic portion of abietic acid. It means a cyclic skeleton in which two existing unsaturated double bonds are converted to saturated hydrocarbons by a method such as hydrotreating. The rosin containing 40% by weight or more of the tetrahydroabietic acid skeleton component or a derivative of the rosin is not particularly limited in its production method as long as it satisfies the condition of containing 40% by weight or more of the tetrahydroabietic acid skeleton component, Examples thereof include a resin obtained by hydrotreating a raw material rosin, a resin obtained by subjecting a raw material rosin to a hydrogenation treatment and derivatization, and a resin obtained by subjecting a raw material rosin to a derivatization treatment and then a hydrogenation treatment. The content of the tetrahydroabietic acid skeleton in the rosin or its derivative is more preferably 50% by weight or more, and particularly preferably 70% by weight or more. A content of 40% by weight or more is preferable because the action as a chain terminator for radical polymerization is reduced.

Rosin and its derivatives containing 40% by weight or more of the components of the tetrahydroabietic acid type skeleton are
For example, gum rosin, wood rosin, tall oil rosin, polymerized rosin and the aforementioned gum rosin, wood rosin,
Tall oil rosin, maleic acid, maleic anhydride, fumaric acid, unsaturated rosin modified with unsaturated acids such as (meth) acrylic acid, polyhydric alcohols.
Dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol and neopentyl glycol; trihydric alcohols such as glycerin, trimethylolethane and trimethylolpropane; tetrahydric alcohols such as pentaerythritol and diglycerin; hexahydric alcohols such as dipentaerythritol Examples of rosin ester compounds and the like that have undergone an esterification reaction with alcohols and the like include those containing a tetrahydroabietic acid skeleton component in an amount of 40% by weight or more.

The hydrogenation catalyst used for producing rosin or its derivative containing 40% by weight or more of the tetrahydroabietic acid type skeleton component is a supported catalyst such as palladium-carbon, rhodium-carbon or platinum-carbon, nickel. Various known materials such as metal powders of platinum and the like can be exemplified. The amount of the catalyst used is usually about 0.01 to 10% by weight, preferably 0.01 to 5% by weight, based on rosin, and the reaction temperature is about 100 to 300 ° C, preferably 150 ° C as a lower limit and 290 ° C as an upper limit. In addition, the hydrogen pressure is usually in a sealed container under atmospheric pressure to about 20 MPa, preferably about 5 MPa as the lower limit. The hydrogenation treatment is carried out by appropriately combining these conditions so that the content of the tetrahydroabietic acid-type skeleton in the hydrogenated rosin obtained is 40% by weight or more.

In the present invention, the use ratio of the acrylic monomer and the tackifying resin is appropriately determined in consideration of heat removal control during the bulk polymerization reaction, the acrylic partially polymerized composition to be obtained and adhesive performance. To be done. Usually acrylic monomer 1
10 to 100 parts by weight, preferably 1
It is used in a proportion of 5 to 80 parts by weight, more preferably 20 to 50 parts by weight. From the viewpoint of heat removal control, the amount of the tackifying resin used is preferably 10 parts by weight or more, and from the viewpoint of the properties of the acrylic polymer composition (in a uniform compatible state) and the adhesive property. The amount is preferably 100 parts by weight or less.

In the production method of the present invention, since radical polymerization is carried out by heating in the absence of a solvent, components such as an organic solvent and water are not substantially contained. The thermal decomposition type polymerization initiator used in the production method of the present invention is not particularly limited, and a general one can be used. Examples of the polymerization initiator include peroxides such as benzoyl peroxide, cumene hydroperoxide and ditertiary butyl peroxide, 2,2′-azobisisobutyronitrile and 2,2′-azobis (2,4 -Dimethylvaleronitrile), 2,2'-azobis (4-methoxy-)
2,4-dimethylvaleronitrile), dimethyl-2,
Azo compounds such as 2'-azobisisobutyrate can be mentioned. Above all, it is preferable to use 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) because the calorific value in the system can be suppressed to a low level.

In the present invention, the thermal decomposition type polymerization initiator as described above is added to 0.00 parts by weight with respect to 100 parts by weight of the acrylic monomer.
It is used in an amount of 5 parts by weight or more and 0.5 parts by weight or less, preferably 0.01 parts by weight or more and 0.3 parts by weight or less, more preferably 0.02 parts by weight or more and 0.2 parts by weight or less. The amount of the thermal decomposition type polymerization initiator used is preferably 0.005 parts by weight or more because the polymerization reaction time can be shortened, and the amount of 0.5 parts by weight or less suppresses the amount of heat generated during radical polymerization and safely controls It is preferable because it is possible. The polymerization initiator may be added to the entire system at once, or may be added in small amounts in multiple stages.

In the production method of the present invention, the reaction temperature is 4
It is performed at 0 ° C. or higher and 120 ° C. or lower, preferably 100 ° C. or lower, and more preferably 80 ° C. or lower. A reaction temperature of 40 ° C. or higher is preferable because the polymerization reaction time can be shortened, and a reaction temperature of 120 ° C. or lower is preferable because the amount of heat generated during polymerization can be suppressed and safely controlled.

The reaction time in the production method of the present invention is 5
Minutes or more and 300 minutes or less, preferably 10 minutes or more and 240 minutes or less, more preferably 20 minutes or more and 180 minutes or less. By setting the reaction time to 5 minutes or longer, the polymerization reaction can proceed to the target polymerization rate, and by setting it to 300 minutes or less, the productivity can be improved, which is preferable.

In the production method of the present invention, it is preferable to use a chain transfer agent such as normal dodecyl mercaptan, butyl mercaptan, 3-mercaptopropionic acid, thioglycolic acid or thioglycolic acid ester as a molecular weight modifier. Such a chain transfer agent is usually used in an amount of 0.001 to 10 with respect to 100 parts by weight of the acrylic monomer.
Used by weight.

In the production method of the present invention, the reaction system may be a batch system, a method utilizing a single-screw, twin-screw extruder or the like, but it is preferable to use the batch reaction system from the viewpoint of equipment cost. .

By adopting the production method of the present invention in this way, an acrylic partially polymerized composition in which 15 to 80% by weight of the acrylic monomer is polymerized can be obtained. The acrylic partially polymerized composition thus obtained is usually about 1 to 100 Pa · s (measured by a B-type viscometer at 23 ° C.), preferably about 3 to 50 Pa · s, and has a weight average molecular weight of 10,000 to 600,000. It has a viscosity suitable for coating, preferably about 30,000 to 400,000. The viscosity and weight average molecular weight can be adjusted by appropriately adjusting the amount of the thermal decomposition type polymerization initiator used, the polymerization temperature, the polymerization time, the amount of the chain transfer agent added, and the like. It is also possible to add an acrylic monomer to the acrylic partial polymer composition obtained in order to adjust the viscosity and the weight average molecular weight and dilute it.

The acrylic partial polymer composition obtained by the production method of the present invention can be used as a pressure-sensitive adhesive composition by a generally known method. For example, a material such as a film or a tape, which has been applied to a substrate and then UV-polymerized, is used as the pressure-sensitive adhesive composition. Therefore, it is possible to add a photopolymerization initiator to the radical polymerization system by heat in advance, or after obtaining the acrylic partial polymer composition after radical polymerization by heat, add a photopolymerization initiator thereto. You may add and use it. The type of photopolymerization initiator is not particularly limited, and general ones can be used. For example, acetophenone-based photopolymerization initiators such as 4-phenoxydichloroacetophenone and 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzoin-based photopolymerization initiators such as benzoin and benzoin methyl ether, benzophenone and benzoyl. Examples thereof include benzophenone-based photopolymerization initiators such as benzoic acid and thioxanthone-based photopolymerization initiators such as thioxanthone and 2-chlorothioxanthone.

In addition, in the production method of the present invention, the adhesive performance of ordinary additives such as fillers such as inorganic substances and organic substances, foaming agents, dyes, pigments, polymerization inhibitors, stabilizers, etc., which are compounded in the adhesive, is impaired. It may be blended to such an extent that it does not exist.

[0029]

EFFECTS OF THE INVENTION According to the production method of the present invention, there is no problem of working environment hygiene in solvent-type pressure-sensitive adhesives, and a process for evaporating and drying water components in suspension-polymerization pressure-sensitive adhesives or emulsion-type pressure-sensitive adhesives In addition, it is easy to control the heat of polymerization in the conventional bulk polymerization pressure-sensitive adhesive manufacturing process, and it is not necessary to use special manufacturing equipment. Can be manufactured safely and economically. The acrylic partially polymerized composition of the present invention obtained by the production method can easily adjust the viscosity when applied to a substrate. In addition, the pressure-sensitive adhesive of the present invention prepared from the acrylic partially polymerized composition exhibits excellent pressure-sensitive adhesive properties, particularly for difficult-to-adhere adherends such as polyolefins, by UV polymerization.

[0030]

EXAMPLES The present invention will be described in more detail with reference to production examples, examples and comparative examples, but the present invention is not limited to these examples. Parts and% are based on weight.

Production Example 1 (Production of hydride of alcohol-modified DCPD resin) Alcohol-modified DCPD was placed in a 1 liter autoclave.
Petroleum resin (trade name "Quinton 1700", manufactured by Nippon Zeon Co., Ltd., softening point 102.0 ° C, number average molecular weight 36
0) 500 parts and 7 parts of nickel / diatomaceous earth catalyst (supporting amount of nickel: 50% by weight) were charged, the temperature was kept at 260 ° C., and hydrogenation was carried out at a hydrogen pressure of 20 MPa for 5 hours. Then, the hydride of the obtained alcohol-modified DCPD petroleum resin was taken out, dissolved in 500 parts of toluene, the catalyst was removed by filtration, and then the solvent was removed under reduced pressure at 200 ° C. and 2.7 kPa for 30 minutes to obtain a softening point of 100. 450 parts of an alcohol-modified DCPD petroleum resin hydride at 450 ° C. was obtained. Table 1 shows the color tone, the hydroxyl value, the hydrogenation rate of unsaturated bonds, and the number average molecular weight of the obtained hydrogenated product of the alcohol-modified DCPD-based petroleum resin (hereinafter referred to as “resin A”).

The softening point is the ring and ball method (JIS K220).
It is the measured value according to 7). The color tone is based on Hazen Standard Color (H) (ASTM D1209). The hydroxyl value is determined by potentiometric titration (JIS K0070). The hydrogenation rate of unsaturated bonds was calculated by measuring a proton nuclear magnetic resonance spectrum ( ¹ H-NMR). That is, a deuterium-substituted chloroform (CDCl ₃ ) solution having the same concentration of the raw material resin and the obtained hydride was prepared, and ¹
H-NMR was measured and calculated from the H-spectrum derived from the unsaturated double bond appearing in the vicinity of 5 to 6 ppm based on the following formula. Hydrogenation rate = {1- (spectrum area derived from unsaturated double bond of hydride / spectrum area derived from unsaturated double bond of raw material resin)} × 100 (%). The number average molecular weight is gel permeation chromatography (manufactured by Tosoh Corporation, HLC8120, column used: TSK).
Gel Super HM-L × 3, developing solvent: tetrahydrofuran).

Production Example 2 460 parts of "Resin B" were obtained by the same procedure as in Production Example 1 except that the nickel / diatomaceous earth catalyst was changed to 4 parts. Table 1 shows the color tone, hydroxyl value, hydrogenation rate of unsaturated bond, and number average molecular weight.

[0034]

[Table 1]

Production Example 3 (1) Hydrogenated autoclave containing 1000 parts of unpurified Chinese gum rosin and 5% palladium carbon as a hydrogenation catalyst (water content 50
%) To remove oxygen in the system, pressurize the system to 10 MPa with hydrogen, raise the temperature to 260 ° C. with stirring, and perform hydrogenation at the same temperature for 3 hours to obtain an acid value. 172, a softening point of 82 ° C., and a hydrogenated rosin having a color tone of Gardner Color 5 were obtained.

(2) Esterification reaction 500 g of the hydrogenated rosin obtained in (1) above was placed in a 1-liter four-necked flask, heated to 180 ° C. under a nitrogen stream, and melted and stirred at 200 ° C. to give glycerin. After adding 50 parts, the temperature was raised to 280 ° C., and an esterification reaction was carried out at the same temperature for 12 hours to obtain a resin C. Table 2 for acid value, softening point and color tone
Shown in.

Production Example 4 (1) Hydrogenation Treatment Hydrogenation was carried out in the same manner as in Production Example 3 (1) except that the hydrogenation catalyst amount was changed to 7 parts in Production Example 3 (1), and an acid value of 1 was obtained.
A hydrogenated rosin having a softening point of 70 and a Gardner color of 5 was obtained.

(2) Purification treatment The hydrogenated rosin obtained in the above (1) was placed in a nitrogen stream at 40
Distilled under reduced pressure of 0 Pa, acid value 175, softening point 85 ℃,
The main fraction of 210 to 280 ° C. having the constant of color tone Gardner 1 was used as the purified hydrogenated rosin.

(3) Esterification reaction Esterification was carried out in the same manner as in Production Example 3 (2) except that the purified hydrogenated rosin obtained in (2) above was used in Production Example 3 (2). A purified hydrogenated rosin ester having a valency of 5, a softening point of 97 ° C. and a color tone of Gardner Color 2 was obtained.

(4) Dehydrogenation treatment Purified hydrogenated rosin ester 200 obtained in the above (3)
Parts and 1 part of 5% palladium carbon were placed in a shaking autoclave to remove oxygen in the system, then the system was pressurized to 150 kPa with hydrogen and heated to 270 ° C., and dehydrogenated at the same temperature for 3 hours. Then, a resin D was obtained. Table 2 shows the acid value, softening point, and color tone.

Production Example 5 (1) Hydrogenation Treatment In Production Example 3 (1), hydrogenation was carried out in the same manner as in Production Example 3 (1) except that the amount of the hydrogenation catalyst was changed to 5 parts.
Thus, hydrogenated rosin having a softening point of 67 and a Gardner color of 4 was obtained.

(2) Esterification Reaction Esterification was carried out in the same manner as in Production Example 3 (2) except that the hydrogenated rosin obtained in (1) above was used in Production Example 3 (2) to give Resin E. Got Table 2 for acid value, softening point and color tone
Shown in.

The content of the tetrahydroabietic acid ester contained in each rosin ester (resin C to E) is such that each rosin ester is hydrolyzed and the hydrolysis product is
It was determined by measuring by gas chromatography analysis according to STMD3008-82.

[0044]

[Table 2]

Production Example 6 (Production of Acrylic Partial Polymer Composition) n-Butyl acrylate 90.0 was placed in a flask equipped with a thermometer, a nitrogen inlet tube, a reflux condenser, a dropping funnel and a stirrer.
Parts, 2-ethylhexyl acrylate 54.0 parts, acrylic acid 6.0 parts, n-dodecyl mercaptan 0.1 part and "resin A" 50.0 parts were charged, and the temperature was raised to 50 ° C to obtain a solution. Next, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) dissolved in 3 ml of n-butyl acrylate (trade name V-70 (Wako Pure Chemical Industries, Ltd.
0.1 part was added dropwise. Foaming due to decomposition of the initiator was confirmed, and the viscosity gradually increased, but no rise in the system temperature was observed. Incubate for 30 minutes at 50 ℃,
Polymerization rate 40%, weight average molecular weight 100,000, viscosity 5.0 Pa
An acrylic partial polymer composition (A) of s was obtained.

Production Examples 7-10 In Production Example 6, instead of "Resin A", "Resin B-
The same operation as in Production Example 6 was performed except that "E" was used,
Acrylic partial polymer composition (B) described in Table 3
(E) was obtained.

Production Example 11 The same operation as in Production Example 6 was carried out except that the amount of "Resin A" was changed to 30 parts in Production Example 6, resulting in a gradual increase in viscosity and an in-system temperature of 60. It increased to ℃, but no further increase was observed. The temperature was kept as it was at 60 ° C. for 30 minutes to obtain an acrylic partial polymer composition (F) having a polymerization rate of 60%, a weight average molecular weight of 160,000 and a viscosity of 8.0 Pa · s.

Comparative Production Example 1 The same operation as in Production Example 6 was carried out except that the amount of “Resin A” charged was changed to 3 parts in Production Example 6, and as a result, the temperature in the system reached 150 ° C. An inhibitor was added and the reaction was stopped.

Comparative Production Example 2 In Production Example 6, Alcon P- was used instead of "Resin A".
The same operation as in Production Example 6 was carried out except that 100 (hydrogenated petroleum resin, softening point 100 ° C., manufactured by Arakawa Chemical Industry Co., Ltd.) was used, and as a result, the tackifying resin precipitated and a uniform acrylic partial weight was obtained. The combined composition could not be obtained.

Comparative Production Example 3 In Production Example 6, ester gum HP (hydrogenated rosin ester, softening point 85 ° C., tetrahydroabietic acid type skeleton component 24%, manufactured by Arakawa Chemical Industry Co., Ltd.) was used instead of “Resin A”. As a result of carrying out an operation of compatibility with Production Example 5 except that was used, an acrylic partial polymer composition (G) having a polymerization rate of 5%, a weight average molecular weight of 2,000 and a viscosity of 0.3 Pa · s was obtained.

Comparative Production Example 4 90.0 parts of n-butyl acrylate and 2-acrylic acid were placed in a flask equipped with a nitrogen introducing tube, a reflux condenser and a stirrer.
Ethylhexyl 54.0 parts, acrylic acid 6.0 parts, n-
Dodecyl mercaptan 0.1 part, 2-hydroxy-2-
Methyl-1-phenylpropan-1-one (trade name: Darocur 1173, manufactured by Merck Ltd.) was added thereto, and the mixture was irradiated with ultraviolet rays through a glass under a nitrogen stream to give a polymerization rate of 40% and a weight average molecular weight of 10 10,000, viscosity 5.0Pa
Thus, an acrylic partial polymer composition (H) of s was obtained.

[0052]

[Table 3]

Practical example 1 (Preparation of UV-polymerizable pressure-sensitive adhesive) 0.7 part of trimethylol triacrylate and 2-hydroxy-2-methyl-1-based on 100 parts by weight of the acrylic partial polymer composition (A). Phenylpropan-1-one (trade name Darocure 1173, manufactured by Merck) 0.3
The mixture was added and mixed well, and the mixture was coated on a release paper with a Baker type applicator so as to have a thickness of 40 μm. This was covered with a PET film as a tape substrate, 1 J / cm ²
The adhesive tape (A) was obtained by irradiating the ultraviolet ray.

Practical Examples 2 to 6, Comparative Practical Examples 1 and 2 In Practical Example 1, the acrylic partial polymer composition (A) was used.
In place of the acrylic partial polymer composition (B) to (H)
The same operations as in Practical Example 1 were carried out except that was used to obtain adhesive tapes (B) to (H).

(Performance Evaluation Method) (1) Coating Applicability In Examples 1 to 7, the coating suitability of the acrylic polymer composition was observed. The results are shown in Table 4. (○: good, ×:
Defective (liquid dripping))

(2) Adhesive strength The adhesive tapes (A) to (G) obtained in Practical Examples 1 to 7 were used in 2
Cut to a width of 5 mm, peel off the release paper, and attach the adhesive surface to each of the polyethylene and SUS base materials.
According to TC-1, 180 ° peeling was carried out at a peeling speed of 300 mm / min at 20 ° C., and the adhesive force (N / 25 mm) per 25 mm width at that time was measured. The results are shown in Table 4.

[0057]

[Table 4]

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09J 193/04 C09J 193/04 F term (reference) 4J011 AA03 AC04 DA02 FA01 FB01 PA57 PA87 PB39 PC02 PC13 QA02 QA03 QA11 QA21 UA01 WA07 4J026 AA08 AB06 BA05 BA20 BA25 BA27 BA28 BA30 BA32 BA33 BA36 BA43 BB01 DB05 DB23 DB32 DB36 FA05 GA08 4J040 BA201 DB021 DE021 DF011 DF031 DF091 DG001 DK001 EK081 JB08

Claims (7)

[Claims] 1. A radical polymerization is carried out by heating an acrylic monomer in the absence of a solvent in the presence of a tackifying resin which is compatible with the acrylic monomer and has little polymerization inhibition, to thereby carry out radical polymerization. A method for producing an acrylic partial polymer composition, wherein the polymerization rate of the monomer is 15 to 80% by weight. 2. At least one selected from the group consisting of a hydride of an alcohol-modified dicyclopentadiene resin as the tackifying resin, a rosin containing 40% by weight or more of a rosin component having a tetrahydroabietic acid type skeleton, and a derivative of the rosin. The manufacturing method according to claim 1, wherein 3. Acrylic monomer to 100 parts by weight,
The manufacturing method according to claim 1, wherein the tackifying resin is used in an amount of 10 to 100 parts by weight. 4. The method according to claim 1, wherein the radical polymerization temperature of the acrylic monomer is 40 ° C. or higher and 120 ° C. or lower. 5. An acrylic partial polymer composition obtained by the method according to any one of claims 1 to 4. 6. The acrylic partial polymer composition according to claim 5, which is applied to a UV-polymerizable pressure-sensitive adhesive. 7. A pressure-sensitive adhesive composition obtained by ultraviolet-polymerizing the acrylic partial polymer composition according to claim 5 or 6.