JP6004788B2 - RESIN COMPOSITION AND METHOD FOR PRODUCING POLYMER - Google Patents

Description

  The present invention relates to a resin composition in which a telechelic polymer having a hydroxyl group at both ends and a narrow molecular weight distribution and two different types of isocyanate curing agents are blended, particularly a pressure-sensitive adhesive and a method for producing the same.

  In order to obtain a polymer having a high molecular weight, a compound having a reactive group at both ends of a polymer and a compound having two functional groups reactive with the reactive group are reacted. If the compound having a functional group having reactivity with the functional group at the end of the telechelic polymer can be reacted, the compound having the functional group is bonded to the reactive group at the terminal of the telechelic polymer, and the telechelic Molecules are extended outward from both ends of the polymer, and a high molecular weight polymer can be obtained efficiently.

  However, as described above, the synthesis of a telechelic polymer in which reactive groups such as hydroxyl groups are introduced at both ends of the molecule has not been simple.

  Regarding the synthesis of a telechelic polymer having hydroxyl groups at both molecular ends, Patent Document 1 (Japanese Patent Application Laid-Open No. 2007-230947) discloses a living radical polymerization in two directions using a specific dibenzyltrithiocarbonate derivative. A method of performing is disclosed. Patent Document 2 (Japanese Patent Laid-Open No. 2011-52057) uses a specific dibenzyltrithiocarbonate derivative having a hydroxyl group at the molecular end obtained as described above in the presence of a polymerization initiator. It is known that by using RAFT polymer obtained by RAFT polymerization (Reversible Addition-Fragmentation chain Transfer polymerization method) as a starting material, a telechelic polymer having a molecular weight and having a hydroxyl group at the molecular end can be obtained. It has been.

  The telechelic polymer thus obtained has a structure in which a symmetric molecular chain extends from both ends of a molecule around a trithiocarbonate group and a hydroxyl group is bonded to both ends, and the molecular weight is It is a complete one. Further, it is known that when a monomer having a polymerizable double bond is further added to the telechelic polymer thus obtained, the RAFT polymerization reaction proceeds again.

  By the way, the polymer used for pressure-sensitive adhesives usually has a weight average molecular weight of several hundreds of thousands or more, and the viscosity increases as the degree of polymerization increases, taking out from the polymerization apparatus, and subsequent molding processing, coating, etc. There is a problem that is difficult to operate.

  In order to facilitate the handling of a polymer having a high degree of polymerization, it is necessary to use an organic solvent, and the use of such an organic solvent is often undesirable in the environment. In this case, the organic solvent may evaporate to form voids, and the presence of the voids thus formed may cause disadvantages due to the use of organic solvents, such as the adhesive properties may vary. There is a problem. Thus, although attempts have been made to reduce the weight average molecular weight in order to reduce the amount of organic solvent, sufficient adhesive properties cannot often be obtained as the molecular weight is decreased.

  By the way, the (meth) acrylic telechelic polymer obtained by living polymerization of alkyl (meth) acrylate by RAFT polymerization as described above is linear and has hydroxyl groups at both ends of the molecule. If this hydroxyl group is used effectively, the polymer can be taken out as a polymer having a low weight average molecular weight with the amount of solvent used as much as possible, and then further increased through a bond such as a urethane bond, an ester bond or an ether bond. It is considered possible to increase the molecular weight.

  However, it is not possible to find a prior art document that clearly describes how a hydroxyl group at the end of an acrylic telechelic polymer molecule can be used to produce a higher performance adhesive or acrylic resin. could not.

JP 2007-230947 A JP 2011-52057 A

  An object of the present invention is to provide a resin composition composed of a polymer having a high molecular weight and a long chain length and excellent in processability such as coatability and moldability. Another object of the present invention is to provide a pressure-sensitive adhesive that can be applied with a high non-volatile content and has excellent adhesive strength, and a method for producing the pressure-sensitive adhesive. Further, depending on the molecular weight, it is possible to apply without solvent.

  The resin composition (adhesive) of the present invention has a weight average molecular weight (Mw) in the range of 4,000 to 50,000, a molecular weight distribution (Mw / Mn) in the range of 1.10 to 1.60, and in the vicinity of the center of the molecule. Telechelic polymer (A) having a divalent sulfur-containing group represented by the following formula (1) and having both ends of the molecule are hydroxyl groups, a tri- or higher functional isocyanate curing agent (B), and a molecular weight of 300 or less A non-volatile content is 60 to 100%, which is obtained by applying a mixture containing the bifunctional isocyanate curing agent (C) to a release substrate and crosslinking the surface of the release substrate. Yes.

  In the RAFT polymerization reaction in the present invention, bis [alkylhydroxyalkylaminocarbonyl] benzyltrithiocarbonate represented by the following formula (1) is used.

(In the above formula (1), R ¹ is usually an alkyl group having 1 to 4 carbon atoms, preferably 1 to 3 carbon atoms, and R ² is usually 2 to 4 carbon atoms, preferably 2 to 3 carbon atoms. And Ar is a substituted or unsubstituted phenylene group or naphthylene group).

  The bis [alkylhydroxyalkylaminocarbonyl] benzyl trithiocarbonate of the above formula (1) used as a starting material for RAFT polymerization of the present invention is, for example, a trithio represented by the following formula (2) near the center of the molecule. It has a carbonate group.

  And the both terminal of the molecule | numerator has the monovalent group of the terminal hydroxyl group represented by following formula (3), It is characterized by the above-mentioned.

(However, in the above formula (3), R ^{1 is} usually an alkyl group having 1 to 4 carbon atoms, preferably 1 to 3 carbon atoms, and R ² is usually 2 to 4 carbon atoms, preferably 2 to 3 carbon atoms. And Ar is a substituted or unsubstituted phenylene group or naphthylene group).

  Bis [alkylhydroxyalkylaminocarbonyl] benzyltrithiocarbonate as described above can be obtained by introducing a vinyl monomer in the presence of a polymerization initiator and a sulfur atom of -S- (C = S) -S- group. A vinyl polymer is inserted between adjacent methylene groups, and this bis [alkylhydroxyalkylaminocarbonyl] benzyltrithiocarbonate is introduced with many repeating units derived from vinyl groups so that the molecule is extended in the lateral direction. To a telechelic polymer (A-1) having a structure represented by the following formula (4).

(In the above formula (4), R ¹ , R ² and Ar have the same meanings as in the above formulas (1) and (3), A is a divalent group derived from a vinyl polymer, and a and b are Independently, a is an integer usually in the range of 10-200, preferably in the range of 20-100, and b is an integer usually in the range of 10-200, preferably 20-100.

  The telechelic polymer (A-1) of the present invention has a weight average molecular weight (Mw) in the range of 4,000 to 50,000, preferably in the range of 4,000 to 25,000, and a molecular weight distribution (Mw / Mn) of 1.10 to 1.60. It is within the range, preferably within the range of 1.10 to 1.5, has a divalent sulfur-containing group represented by the formula (2) in the vicinity of the center of the molecule, and both ends of the molecule become hydroxyl groups.

  In addition, the method for producing the resin composition of the present invention has a weight average molecular weight (Mw) in the range of 4,000 to 50,000, a molecular weight distribution (Mw / Mn) in the range of 1.10 to 1.60, and near the center of the molecule. A telechelic polymer (A) having a divalent sulfur-containing group represented by formula (1) and having both molecular ends hydroxyl groups, a tri- or higher functional isocyanate curing agent (B), and a molecular weight of 300 A mixture containing the following difunctional isocyanate curing agent (C) is prepared, the mixture is applied to a peelable substrate, the hydroxyl group of the telechelic polymer on the release substrate surface, and a trifunctional or higher functional isocyanate system A resin composition is obtained by reacting the curing agent (B) and the bifunctional isocyanate curing agent (C) with a nonvolatile content of 60 to 100% to form a crosslinked structure.

  According to the present invention, operations such as coating and molding can be performed in a state before the telechelic polymer is increased in viscosity, so that the chain length is finally extended without impairing the ease of handling. Sheets, molded articles, pressure-sensitive adhesive sheets and the like made of the resin composition can be obtained. Furthermore, since the resin composition of the present invention can be in a mode not containing a solvent, it is not only environmentally friendly, but also a high-quality pressure-sensitive adhesive composition that does not cause gaps in the solvent. Can be obtained.

  The resin composition of the present invention has a hydroxyl group at both ends of the molecule, a specific molecular weight, a telechelic polymer (A) having a very narrow molecular weight distribution, a tri- or higher functional isocyanate curing agent (B), and A bifunctional isocyanate curing agent (C) having a specific molecular weight is an essential component.

  Hereinafter, the resin composition of the present invention and its constituent elements will be described in detail.

<Telechelic polymer>
In the present invention, when preparing the telechelic polymer (A) as described above, the formula (1) having a divalent sulfur-containing group in the vicinity of the center of the molecule and a hydroxyl group at both ends as shown below. The bis [alkylhydroxyalkylaminocarbonyl] benzyltrithiocarbonate derivative represented by) is used.

(In the above formula (1), R ¹ is usually an alkyl group having 1 to 4 carbon atoms, preferably 1 to 3 carbon atoms, and R ² is usually an alkylene having 2 to 4 carbon atoms, preferably 2 to 3 carbon atoms. Ar is a substituted or unsubstituted phenylene group or naphthylene group).

  This bis [alkylhydroxyalkylaminocarbonyl] benzyltrithiocarbonate derivative can be synthesized by reacting a group represented by the following formula (2) with a group represented by the formula (3).

(In the above formula (3), R ¹ is usually an alkyl group having 1 to 4 carbon atoms, preferably 1 to 3 carbon atoms, and R ² is usually an alkylene having 2 to 4 carbon atoms, preferably 2 to 3 carbon atoms. And Ar is a substituted, unsubstituted phenylene group or naphthylene group).

  When a polymerization initiator and a vinyl compound are present in the system, the benzyltrithiocarbonate derivative of the above formula (1) reacts to insert a vinyl compound between a sulfur atom and a methylene group adjacent to the sulfur atom. Thus, a telechelic polymer (A-1) represented by the following formula (4) is produced.

(In the above formula (4), R ¹ , R ² and Ar have the same meanings as in the above formulas (1) and (3), A is a divalent group derived from a vinyl polymer, and a and b are Independently, a is an integer usually in the range of 10 to 200, preferably 10 to 100, more preferably 20 to 100, even more preferably 20 to 60, and b is usually 10 to 200, Preferably it is an integer in the range of 10-100, more preferably 20-100, more preferably 20-60).

  Further, by adding an additional vinyl compound and a polymerization initiator to the telechelic polymer represented by the above formula (4), the RAFT polymerization reaction further proceeds. For example, as represented by the following formula (5) It is also possible to produce a telechelic polymer (A-2) in which different vinyl polymers are bonded to each other.

(In the above formula (5), R ¹ , R ² and Ar have the same meanings as in the above formulas (1), (2), (3) and (4), and A is a divalent vinyl polymer-derived divalent B is a divalent group derived from another vinyl group, a, b, c and d are each independently a is usually 10 to 200, preferably 10 to 100, more preferably 20 to 100, more preferably an integer in the range of 20-60, b is usually in the range of 10-200, preferably 10-100, more preferably 20-100, more preferably 20-60, c is Usually an integer in the range 10 to 200, preferably in the range 20 to 60, d is an integer usually in the range 10 to 200, preferably 20 to 100).

  In the present invention, when using the telechelic polymer (A-2), that is, the telechelic polymer in which the polymer chain portion derived from the vinyl compound has a block polymer chain structure, the resulting resin composition, particularly the pressure-sensitive adhesive composition. Is particularly preferable because it has excellent cohesive strength.

  The telechelic polymer (A) used in the present invention (that is, the above (A-1) or (A-2)) has a weight average molecular weight (Mw) in the range of 4,000 to 50,000, preferably 4,000 to 25,000. The polymer can be produced by reacting a vinyl monomer in the presence of a polymerization initiator so that the molecular weight distribution (Mw / Mn) is in the range of 1.10 to 1.60 and 1.10 to 1.50.

  Since the telechelic polymer (A) having a weight average molecular weight (Mw) as described above is a liquid having a low viscosity at room temperature, it can also be used in subsequent steps without using an organic solvent. Further, since the molecular weight distribution (Mw / Mn) is very narrow, the molecular weight distribution (Mw / Mn) of the obtained polymer is hardly widened even when used in the subsequent steps.

<Vinyl compound>
Examples of the vinyl compound used in the present invention include (meth) acrylic monomers such as (meth) acrylic acid ester (a1), alkoxyalkyl (meth) acrylate (a2), and alkoxypolyalkylene glycol mono (meth) acrylate (a3). And other copolymerizable monomers (a4).

  The (meth) acrylic acid ester (a1) is preferably an ester composed of an alkyl group having 1 to 20 carbon atoms. Examples of such monomers include methyl (meth) acrylate, ethyl (meta ) Acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (Meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undeca (meth) acrylate, lauryl (meth) acrylate, oleyl (Meth) acrylate, n-stearyl (meth) acrylate, iso-steer Le (meth) acrylates such as and Jideka (meth) acrylate (meth) acrylate, and the like.

  Examples of the alkoxyalkyl (meth) acrylate (a2) include methoxymethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-methoxypropyl (meth) acrylate, and 3-ethoxy. Mention may be made of propyl (meth) acrylate, 4-methoxybutyl (meth) acrylate and 4-ethoxybutyl (meth) acrylate.

  Examples of the alkoxypolyalkylene glycol mono (meth) acrylate (a3) include methoxydiethylene glycol mono (meth) acrylate, methoxydipropylene glycol mono (meth) acrylate, ethoxytriethylene glycol mono (meth) acrylate, and ethoxydiethylene glycol mono (meth). Examples thereof include acrylate and methoxytriethylene glycol mono (meth) acrylate.

  Examples of the copolymerizable monomer (a4) include vinyl acetate; (meth) acrylonitrile; cyclohexyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate; styrene, methylstyrene, dimethylstyrene, trimethylstyrene, propylstyrene. Alkyl styrenes such as butyl styrene, hexyl styrene, heptyl styrene and octyl styrene, and styrene-based units such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, iodostyrene, nitrostyrene, acetylstyrene and methoxystyrene The body etc. can be mentioned.

  The monomers (a1) to (a4) can be used singly or in combination of two or more. Among these, it is preferable that the blending ratio of (a1) in all monomer components is 80% by weight or more.

  Furthermore, in the present invention, when the telechelic polymer (A) is a telechelic polymer (A-2) having a block polymer chain structure, two different monomer types are selected from (a1). It is preferable.

<Polymerization initiator>
As the polymerization initiator used in the RAFT polymerization, a normal inorganic polymerization initiator and / or organic polymerization initiator can be used.

  The polymerization initiator used in the RAFT polymerization of the present invention includes persulfates such as potassium persulfate and ammonium persulfate, peroxides such as benzoyl peroxide and laurium peroxide, and azo such as asobisisobutyronitrile. A compound etc. can be mentioned. Of these, 2,2′-azobis (2-methylpropionitrile), 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis, which are azo polymerization initiators, are preferable. (2,4-dimethylvaleronitrile), 2,2'-azobis (2-cyclopropylpropionitrile), 1,1'-azobis (cyclohexane-1-carbonitrile) and dimethyl-2,2'-azobis ( 2-methylpropionate). These polymerization initiators can be used alone or in combination of two or more.

  These polymerization initiators are generally used in an amount of 0.01 to 5 parts by weight, preferably 0.5 to 2 parts by weight per 100 parts by weight of the monomer.

  By performing RAFT polymerization as described above, a repeating unit derived from a vinyl monomer is bonded to both sides of a trithiocarbonate in the center or near the center almost evenly, and a hydroxyl group is bonded to both molecular ends. A highly linear chain-like telechelic polymer (A) can be obtained.

<Polymerization conditions>
The reaction temperature of the above RAFT polymerization is usually 60 to 120 ° C., preferably 80 to 110 ° C., and is usually carried out in an inert gas atmosphere such as nitrogen gas. This reaction can be performed under normal pressure, increased pressure, or reduced pressure, but is normally performed at normal pressure. The reaction time is usually 1 to 14 hours, preferably 2 to 6 hours.

  The RAFT polymerization is usually carried out without using a reaction solvent, but a reaction solvent may be used if necessary.

<Resin composition and pressure-sensitive adhesive composition>
The telechelic polymer (A) obtained as described above (that is, (A-1) or (A-2)), a tri- or higher functional isocyanate curing agent (B), and a bifunctional isocyanate curing agent (C ) And reacting them on the substrate, the resin composition of the present invention, particularly the pressure-sensitive adhesive composition, can be formed. The reaction that occurs on the substrate is considered to be due to the following formula (6).

(In the above formula (6), R ¹ , R ² and Ar have the same meanings as in the above formulas (1) and (3), A is a divalent group derived from a vinyl polymer, and a, b Is synonymous with that in formula (4), X represents a divalent group for bonding an isocyanate group, and Y represents a trivalent group for bonding an isocyanate group).

  As is clear from the above formula, even if the bifunctional isocyanate curing agent and the trifunctional or higher functional isocyanate curing agent are bonded to both ends of the telechelic polymer molecule, the isocyanate curing agent contains unreacted isocyanate groups. Since it remains, the above stoichiometry proceeds until the hydroxyl group or isocyanate group is substantially consumed.

  The resin composition of the present invention comprises a mixture of a telechelic polymer (A), a trifunctional or higher functional isocyanate curing agent (B), and a bifunctional isocyanate curing agent (C). Therefore, it can be coated on a substrate without using an organic solvent. That is, according to the present invention, it is possible to reduce the amount of the organic solvent used in the application of the resin composition, particularly the pressure-sensitive adhesive composition, or to apply these without a solvent. In addition, the non-volatile content of the resin composition of the present invention is 60 to 100%, and preferably the non-volatile content is 80 to 100%.

  Further, the reaction between the hydroxyl groups at both molecular ends of the telechelic polymer (A) and the isocyanate groups of the trifunctional or higher functional isocyanate curing agent (B) and the bifunctional isocyanate curing agent (C) having a specific molecular weight. Since these mixtures can be completed by applying the mixture on a base material and curing on the base material, the cross-linking reaction proceeds at an early stage before coating, and the viscosity does not become excessively high. There is no need to add an extra organic solvent during coating.

<Isocyanate curing agent>
Examples of the tri- or higher functional isocyanate curing agent (B) used in the present invention include L-45 (trifunctional tolylene diisocyanate compound: manufactured by Soken Chemical Co., Ltd.), coronate 342 (trifunctional tolylene diisocyanate type). Compound: manufactured by Nippon Polyurethane Industry Co., Ltd.), Coronate HX (Trifunctional Hexamethylene Diisocyanate Compound; manufactured by Nippon Polyurethane Industry Co., Ltd.), Duranate P301-75E (Trifunctional Hexamethylene Diisocyanate Compound; manufactured by Asahi Kasei Corporation) Duranate 24A-100 (trifunctional hexamethylene diisocyanate compound; manufactured by Asahi Kasei Co., Ltd.) Duranate TPA-100 (trifunctional hexamethylene diisocyanate compound; manufactured by Asahi Kasei Co., Ltd.) can be exemplified, and in the present invention, such commercially available Trifunctional or higher functional isocyanate compounds can also be used.

  The bifunctional isocyanate curing agent used in the present invention is a bifunctional isocyanate curing agent having a molecular weight of 300 or less, and is preferably a bifunctional isocyanate curing agent having a molecular weight of 150 to 260. Examples of such bifunctional isocyanate curing agents include tolylene diisocyanate (molecular weight: 174), diphenylmethane diisocyanate (molecular weight: 250), hexamethylene diisocyanate (molecular weight: 168), isophorone diisocyanate (molecular weight 222), xylylene diisocyanate. (Molecular weight: 188).

  The trifunctional or higher functional isocyanate compound (B) and the bifunctional isocyanate curing agent (C) and the blending ratio (C / B) are 1/1 to 1/8, preferably 1/1 to 1/1 / by weight. 4. Furthermore, the compounding amount of the trifunctional or higher functional isocyanate compound (B) is usually 1 to 8 parts by weight, preferably 1 to 5 parts by weight with respect to 100 parts by weight of the telechelic polymer (A). By adjusting the ratio of the trifunctional or higher functional isocyanate curing agent and the bifunctional isocyanate curing agent as described above, desired properties can be expressed in the obtained resin composition or the like.

<Manufacturing method>
In the resin composition of the present invention, the telechelic polymer (A) having hydroxyl groups at both ends of the molecule, the trifunctional or higher functional isocyanate curing agent (B), and the bifunctional isocyanate curing agent (C) were subjected to a release treatment. After flowing on the support and laminating with a cover film that has been peeled off as necessary, it is usually 3 days or more, preferably 7 to 10 days, usually in an environment of 5 to 60 ° C., preferably 15 to 40 ° C. It is prepared by curing under the environment. That is, in the present invention, it is not necessary to perform an operation such as stirring which is usually performed to form a crosslinked structure, and a desired crosslinked structure is formed by curing under predetermined conditions as described above. It is possible.

<Characteristics as pressure-sensitive adhesive composition>
The resin composition of this invention can be used conveniently as an adhesive. The pressure-sensitive adhesive has excellent flexibility while being excellent in cohesiveness. The reason is considered as follows.

  The resin composition of the present invention has a structure in which hard segments derived from the bifunctional isocyanate curing agent (C) and long soft segments derived from the telechelic polymer (A) are alternately continued. Therefore, hard segments and soft segments aggregate weakly in the pressure-sensitive adhesive, and the cohesiveness is enhanced by forming a microphase separation structure (sea-island structure) in the pressure-sensitive adhesive. Furthermore, since a crosslinked structure resulting from the trifunctional or higher functional isocyanate-based curing agent (B) is formed, a cohesive force is also obtained by this. That is, in the resin composition of the present invention, by using the bifunctional isocyanate curing agent (C) and the trifunctional or higher functional isocyanate curing agent (B) in combination, the resulting pressure-sensitive adhesive appears to exhibit an appropriate cohesive force. become. As described above, since the cohesive strength of the pressure-sensitive adhesive of the present invention is increased to an appropriate level, sufficient adhesive strength is obtained and flexibility is not lost.

<Use of resin composition>
Applications of the resin composition obtained by the production method of the present invention include, but are not limited to, a pressure-sensitive adhesive, a resin film, an adhesive, and the like.

EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.
Each measured value in the examples was determined by the following method.

<Molecular weight and molecular weight distribution>
The weight average molecular weight (Mw) and number average molecular weight (Mn) in terms of standard polystyrene were determined by gel permeation chromatography (GPC) under the following conditions.

(GPC measurement conditions)
Measuring device: HLC-8120GPC (manufactured by Tosoh Corporation)
GPC column configuration: The following five columns (all manufactured by Tosoh Corporation)
(1) TSK-GEL HXL-H (guard column)
(2) TSK-GEL G7000HXL
(3) TSK-GEL GMHXL
(4) TSK-GEL GMHXL
(5) TSK-GEL G2500HXL
Diluted with tetrahydrofuran so that the sample concentration is 1.0 mg / cm ³ Mobile phase solvent: Tetrahydrofuran Flow rate: 1.0 cm ³ / min
Column temperature: 40 ° C.

<Viscosity measurement>
A 500 ml bottle containing varnish was immersed in a constant temperature water bath at 25 ° C. and allowed to stand for 12 hours, and then measured according to the measurement method of a B-type viscometer.

<Nonvolatile content (nV%) measurement>
1 g of the acrylic polymer solution was placed in a precisely weighed tin plate (n1), the total weight (n2) was precisely weighed, and then heated at 105 ° C. for 3 hours. Thereafter, the tin plate was allowed to stand in a desiccator at room temperature for 1 hour, then weighed again, and the total weight (n3) after heating was measured. Using the obtained weight measurement values (n1 to n3), the nonvolatile content was calculated from the following formula.
Nonvolatile content (%) = 100 x [weight after heating (n3-n1) / weight before heating (n2-n1)]

<Peeling force (N / 25mm)>
Under 23 ° C and 50% RH conditions, the polyethylene terephthalate (PET) film of the pressure-sensitive adhesive sheets (pressure-sensitive adhesive layer thickness is 25 µm) obtained in the examples and comparative examples is peeled off, and the exposed pressure-sensitive adhesive layer surface is made of stainless steel (SUS) Were bonded using a 2 kg roller (bonding area 25 mm × 70 mm).
Twenty minutes after bonding, the test piece was peeled off from the SUS plate in the 180 ° direction at 300 mm / min, and the peel strength (adhesive strength) of the pressure-sensitive adhesive layer was measured.

<Retention force test>
Under 23 ° C and 50% RH conditions, the polyethylene terephthalate (PET) film of the pressure-sensitive adhesive sheets (pressure-sensitive adhesive layer thickness is 25 µm) obtained in the examples and comparative examples is peeled off, and the exposed pressure-sensitive adhesive layer surface is made of stainless steel (SUS) Were bonded using a 2 kg roller (bonding area 20 mm × 20 mm).
20 minutes after bonding, a load of 1 kg was applied under the condition of 40 ° C. dry, and the distance from the original position after 1 hour was measured. When falling within 1 hour, it was described as falling.

<Constant load test>
Under 23 ° C and 50% RH conditions, the polyethylene terephthalate (PET) film of the adhesive sheet (adhesive layer thickness is 25μm) obtained in the examples and comparative examples was peeled off, and the exposed adhesive layer surface was made of stainless steel (SUS) Were bonded using a 2 kg roller (bonding area 20 mm × 20 mm).
20 minutes after bonding, a load of 100 g was applied under the condition of 40 ° C. dry, and peeling after 1 hour was measured. When falling within 1 hour, it was described as falling.

<Ball tack test>
According to the J. Dow method, the measurement was performed under conditions of a running distance, 10 cm, a running distance, 10 cm, a temperature, 23 ° C., and a humidity of 65% RH.

[Production Example 1: Acrylic polymer (1)]
To a flask equipped with a stirrer, a nitrogen gas inlet tube, a thermometer and a reflux condenser, 100 parts by weight of butyl acrylate, bis [4- {ethyl-2- (hydroxyethyl) aminocarbonyl} -benzyl] trithiocarbonate ( 2 parts by weight of RAFT agent manufactured by Nippon Terpene Co., Ltd. was charged, and the contents of the flask were heated to 80 ° C. while introducing nitrogen gas into the flask. Next, 0.03 part by weight of AIBN sufficiently purged with nitrogen gas was added to the flask under stirring, and the contents in the flask were heated and cooled for 4 hours so that the temperature of the contents in the flask could be maintained at 80 ° C. Part by weight was added. The 105 ° C. heating residue measured for the acrylic polymer (1) thus obtained was 79.8%. The obtained acrylic polymer (1) had a Mn of 15,000, a Mw of 18,000, a molecular weight distribution of 1.18, and a viscosity at 23 ° C. of 1.6 Pa · s.

[Production Example 2: Acrylic polymer (2)]
An acrylic polymer (2) was produced in the same manner as in Production Example 1 except that 100 parts by weight of 2-ethylhexyl acrylate was used instead of 100 parts by weight of butyl acrylate. The 105 ° C. heating residue (nV) of the acrylic polymer (2) was 79.5%. The molecular weight of the obtained acrylic polymer (2) was 15,000 for Mn, 18,000 for Mw, 1.20 for molecular weight distribution, and 1.5 Pa · s at 23 ° C.

[Production Example 3: Acrylic polymer (3)]
In a flask equipped with a stirrer, a nitrogen gas inlet tube, a thermometer and a reflux condenser, 17 parts by weight of methyl acrylate, bis [4- {ethyl-2- (hydroxyethyl) aminocarbonyl} -benzyl] trithiocarbonate ( 2 parts by weight of RAFT agent manufactured by Nippon Terpene Co., Ltd. was charged, and the contents of the flask were heated to 80 ° C. while introducing nitrogen gas into the flask. Then, 0.03 part by weight of AIBN sufficiently substituted with nitrogen gas was added to the flask under stirring, and heating and cooling were performed for 2 hours so that the temperature of the contents in the flask could be maintained at 80 ° C. The heating residue at 105 ° C. of the acrylic polymer thus obtained was 0.5%. Next, after the temperature of the contents in the flask was raised to 90 ° C., 66 parts by weight of butyl acrylate was added dropwise over 1 hour. Thereafter, heating and cooling were performed for 3 hours so that the temperature of the contents in the flask could be maintained at 90 ° C., and finally 25 parts of ethyl acetate was added. The acrylic polymer (3) thus obtained had a heating residue at 105 ° C. of 79.8%. The molecular weight of the resulting acrylic polymer (3) measured by gel permeation chromatography (GPC) was Mn1.5, Mw 18,000, dispersion index 1.2, and viscosity at 23 ° C was 2.5 Pa · s. there were.

[Production Example 4: Acrylic polymer (4)]
In a flask equipped with a stirrer, nitrogen gas inlet tube, thermometer and reflux condenser, butyl acrylate 99.9 parts by weight, 2-hydroxyethyl acrylate 0.1 parts by weight, NDM (N-dodecyl mercaptan) 0.12 parts by weight, ethyl acetate 79 parts by weight The contents of the flask were heated to 66-67 ° C. while introducing nitrogen gas into the flask. Next, after sufficiently purging with nitrogen gas, 0.1 part by weight of a polymerization initiator V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) was added to the flask with stirring. Heating and cooling were performed for 4 hours so that the temperature of the contents in the flask could be maintained at 66-67 ° C. The acrylic polymer (4) thus obtained had a heating residue at 105 ° C. of 48.8%. Further, the molecular weight measured for the obtained polymer (4) was Mn = 88,000, Mw = 23,000, the dispersion index was 2.81, and the viscosity at 23 ° C. was 6.1 Pa · s.

[Production Example 5: Acrylic polymer (5)]
It was prepared by the same procedure as in Production Example 1 except that the amount of RAFT agent was changed to 0.1 parts by weight.

[Production Example 6: Acrylic polymer (6)]
It was prepared by the same procedure as in Production Example 1 except that the amount of RAFT agent was changed to 10 parts by weight.
The measurement results of the monomer composition, molecular weight, etc. constituting the acrylic polymers (1) to (6) are shown in Table 1 below.

[Examples 1 to 10 ]
In each of the acrylic polymers (1) to (3) obtained in the above production examples, a trifunctional or higher functional isocyanate curing agent and a bifunctional isocyanate curing agent shown in Table 2 are blended as shown in Table 2, and well. Mixed.
After defoaming, it was applied to a PET separator (trade name: Therapy MFA; manufactured by Toray Film Co., Ltd.) with a thickness of 25 μm using a doctor blade, and immediately dried at 80 ° C. for 3 minutes.
After drying for 3 minutes, a polyethylene terephthalate (PET) film having a thickness of 25 μm was placed on the surface of the uncoated adhesive, and bonded to each other, and allowed to stand for 7 days at room temperature of 23 ° C. and humidity of 65%.
Then, this sheet | seat was cut | judged to the magnitude | size defined to each measuring method, and the adhesive force, the retention strength, and the constant load test were done on the following conditions, respectively. The properties of the obtained pressure-sensitive adhesive sheet are shown in Table 2 below.

[Comparative Examples 1 to 10]
Except that the curing agent was blended in the blending amounts shown in Table 3 below for each of the acrylic polymers obtained in the above production examples (1), (4), (5) and (6), the same as in the examples. An adhesive sheet was prepared according to the procedure. The physical properties of the obtained pressure-sensitive adhesive sheet are also shown in Table 3.

Claims (12)

Divalent sulfur represented by the formula (2) near the center of the molecule having a weight average molecular weight (Mw) in the range of 4,000 to 50,000, molecular weight distribution (Mw / Mn) in the range of 1.10 to 1.60. A telechelic polymer (A) having a contained group and having both hydroxyl groups at the ends, a trifunctional or higher functional isocyanate curing agent (B), and a bifunctional isocyanate hardener (C) having a molecular weight of 300 or less. A resin composition having a nonvolatile content of 60 to 100%, which is obtained by applying a mixture to a peelable substrate and causing a crosslinking reaction on the surface of the peelable substrate .
The amount of the tri- or higher functional isocyanate curing agent (B) in the mixture is 1 to 8 parts by weight with respect to 100 parts by weight of the telechelic polymer (A), and
The weight ratio (C / B) of the difunctional isocyanate curing agent (C) to the trifunctional or higher isocyanate curing agent (B) is in the range of 1/1 to 1/8. A resin composition .

  The resin composition according to claim 1, wherein the resin composition is a pressure-sensitive adhesive composition. A telechelic polymer (A) having a divalent sulfur-containing group represented by the formula (2) in the vicinity of the center of the molecule and a hydroxyl group at both molecular ends is a dibenzyltrithio represented by the following formula (1). The resin composition according to claim 1 or 2, wherein a carbonate derivative is obtained by polymerizing a (meth) acrylic monomer by RAFT polymerization;

(In the above formula (1), Ar is either a phenylene group or a naphthylene group, R ¹ is an alkyl group having 1 to 4 carbon atoms, and R ² is an alkylene group having 2 to 4 carbon atoms. is there). The telechelic polymer (A) having a divalent sulfur-containing group represented by the formula (2) in the vicinity of the center of the molecule and having both molecular ends hydroxyl groups is represented by the following formula (4): The resin composition according to any one of claims 1 to 3;

(In the above formula (4), Ar is either a phenylene group or a naphthylene group, R ¹ is an alkyl group having 1 to 4 carbon atoms, and R ² is an alkylene group having 2 to 4 carbon atoms. A is a repeating unit derived from a (meth) acrylic monomer, and a and b each independently represents an integer of 10 to 200). The said resin composition does not contain an organic solvent, The resin composition of any one of Claims 1-4 characterized by the above-mentioned. The resin composition according to any one of claims 1 to 5 , wherein the telechelic polymer (A) has a molecular weight distribution of 1.10 to 1.50. Divalent sulfur represented by the formula (2) near the center of the molecule having a weight average molecular weight (Mw) in the range of 4,000 to 50,000, molecular weight distribution (Mw / Mn) in the range of 1.10 to 1.60. A telechelic polymer (A) having a containing group and having both ends of the molecule are hydroxyl groups, a trifunctional or higher functional isocyanate curing agent (B), and a bifunctional isocyanate curing agent (C) having a molecular weight of 300 or less. A mixture is prepared, the mixture is applied to a peelable substrate, the hydroxyl group of the telechelic polymer (A) on the surface of the release substrate, a tri- or higher functional isocyanate curing agent (B), and a bifunctional isocyanate-based curing It is a method for producing a resin composition in which a crosslinking structure is formed by reacting an agent (C) with a nonvolatile content of 60 to 100% .
The amount of the tri- or higher functional isocyanate curing agent (B) in the mixture is 1 to 8 parts by weight with respect to 100 parts by weight of the telechelic polymer (A), and
The weight ratio (C / B) of the difunctional isocyanate curing agent (C) to the trifunctional or higher isocyanate curing agent (B) is in the range of 1/1 to 1/8. A method for producing a resin composition.

The method for producing a resin composition according to claim 7 , wherein the resin composition is a pressure-sensitive adhesive composition. A telechelic polymer (A) having a divalent sulfur-containing group represented by the formula (2) in the vicinity of the center of the molecule and a hydroxyl group at both molecular ends is a dibenzyltrithio represented by the following formula (1). The method for producing a resin composition according to claim 7 or 8 , wherein a carbonate derivative is polymerized with a (meth) acrylic monomer by RAFT polymerization;

(In the above formula (1), Ar is either a phenylene group or a naphthylene group, R ¹ is an alkyl group having 1 to 4 carbon atoms, and R ² is an alkylene group having 2 to 4 carbon atoms. is there). The telechelic polymer (A) having a divalent sulfur-containing group represented by the formula (2) in the vicinity of the center of the molecule and having both molecular ends hydroxyl groups is represented by the following formula (4): method for producing a resin composition according to any one of claims 7-9;

(In the above formula (4), Ar is either a phenylene group or a naphthylene group, R ¹ is an alkyl group having 1 to 4 carbon atoms, and R ² is an alkylene group having 2 to 4 carbon atoms. A is a repeating unit derived from a (meth) acrylic monomer, and a and b each independently represents an integer of 10 to 200). Method for producing the resin composition, the resin composition according to any one of claims 7 to 10, characterized in that no organic solvent. The method for producing a resin composition according to any one of claims 7 to 11 , wherein the telechelic polymer (A) has a molecular weight distribution of 1.10 to 1.50.