Use of rosin polyol, tackifier, pressure-sensitive adhesive composition, acrylic pressure-sensitive adhesive composition, active energy ray-curable acrylic pressure-sensitive adhesive composition, and rosin polyol

Abstract

To provide a novel rosin-based resin that can endow a viscoadhesive composition with high holding power and adhesive strength.SOLUTION: A rosin polyol has a weight average molecular weight of 1,500-3,500.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a rosin polyol, a tackifier, a pressure-sensitive adhesive composition, an acrylic pressure-sensitive adhesive composition, an active energy ray-curable acrylic pressure-sensitive adhesive composition, and use of the rosin polyol. [Background technology]

[0002] Pressure-sensitive adhesive compositions used in labels, pressure-sensitive adhesive tapes, double-sided adhesive tapes, etc. are required to have adhesive properties such as tack, adhesive strength, and holding power, taking into account the environment in which they are used.

[0003] Generally, pressure-sensitive adhesive compositions are primarily composed of base polymers such as acrylic polymers, rubber elastomers (natural rubber, synthetic rubber), and ethylene-vinyl acetate copolymers, but because these base polymers alone do not provide sufficient adhesive strength to various adherends, they are used as compositions containing tackifying resins such as rosin esters, petroleum resins, and terpene resins (see, for example, Patent Document 1).However, even with such pressure-sensitive adhesive compositions, it has sometimes been difficult to obtain one that is excellent in both adhesive strength and holding power.

[0004] Furthermore, as pressure-sensitive adhesive compositions, solvent-free active energy ray-curable acrylic pressure-sensitive adhesive compositions (active energy ray-curable acrylic pressure-sensitive adhesive compositions) containing acrylic oligomers and acrylic monomers as main components have also been proposed in order to reduce environmental impact, etc. (see, for example, Patent Document 2). These active energy ray-curable acrylic pressure-sensitive adhesive compositions may also contain tackifying resins such as rosin esters, petroleum resins, and terpene resins to improve adhesive properties, but even in such cases, it has often been difficult to obtain compositions that exhibit both excellent adhesive strength and holding power. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2016-222824 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-101460 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a novel rosin-based resin that can impart high holding power and adhesive strength to a pressure-sensitive adhesive composition.

[0007] Another object of the present invention is to provide a novel tackifier that can impart high holding power and adhesive strength to a pressure-sensitive adhesive composition.

[0008] Another object of the present invention is to provide a novel pressure-sensitive adhesive composition having high holding power and adhesive strength. [Means for solving the problem]

[0009] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by a rosin polyol having a specific weight-average molecular weight. The present inventors have also found that the above-mentioned problems can be solved by a tackifier and a pressure-sensitive adhesive composition containing the above-mentioned rosin polyol. Specifically, the present invention relates to the following rosin polyol, tackifier, pressure-sensitive adhesive composition, acrylic pressure-sensitive adhesive composition, active energy ray-curable acrylic pressure-sensitive adhesive composition, and use of the rosin polyol.

[0010] 1. A rosin polyol having a weight average molecular weight of 1,500 to 3,500.

[0011] 2. The rosin polyol according to item 1, having a hydroxyl value of 130 mgKOH / g or more.

[0012] 3. A tackifier comprising the rosin polyol according to item 1 or 2 above.

[0013] 4. A pressure-sensitive adhesive composition comprising the rosin polyol according to item 1 or 2 above.

[0014] 5. An acrylic pressure-sensitive adhesive composition comprising the rosin polyol according to item 1 or 2 above.

[0015] 6. An active energy ray-curable acrylic pressure-sensitive adhesive composition containing the rosin polyol according to item 1 or 2.

[0016] 7. Use of the rosin polyol according to item 1 or 2 above as a tackifier. [Effects of the Invention]

[0017] The rosin polyol of the present invention can improve the holding power and adhesive strength of a pressure-sensitive adhesive composition containing the rosin polyol. The rosin polyol of the present invention particularly improves the holding power and adhesive strength of an acrylic pressure-sensitive adhesive composition.

[0018] The tackifier of the present invention contains the rosin polyol, thereby improving the holding power and adhesive strength of a pressure-sensitive adhesive composition. The tackifier of the present invention particularly improves the holding power and adhesive strength of an acrylic pressure-sensitive adhesive composition.

[0019] The pressure-sensitive adhesive composition of the present invention contains the above-mentioned rosin polyol, thereby exhibiting high holding power and adhesive strength. In particular, the acrylic pressure-sensitive adhesive composition contains the above-mentioned rosin polyol, thereby exhibiting high adhesive strength to polar adherends such as glass and metal. BEST MODE FOR CARRYING OUT THE INVENTION

[0020] Throughout this specification, the range of the values ​​of the physical properties, contents, etc. may be set as appropriate (for example, by selecting from the values ​​described in each item below). Specifically, when the example of the value α is A3, A2, or A1 (assuming A3>A2>A1), the range of the value α may be, for example, A3 or less, A2 or less, less than A3, less than A2, A1 or more, A2 or more, greater than A1, greater than A2, A1 to A2 (A1 or more and less than A2), A1 to A3, A2 to A3, A1 or more and less than A3, A1 or more and less than A2, A2 or more and less than A3, greater than A1 and less than A3, greater than A1 and less than A2, greater than A2 and less than A3, greater than A1 ... and the like.

[0021] [Rosin polyol] The rosin polyol of the present invention is not particularly limited, and various known rosin polyols can be used as long as they have a weight average molecular weight of 1,500 to 3,500. The above rosin polyols may be used alone or in combination of two or more.

[0022] The rosin polyol is not particularly limited as long as it is a reaction product of reaction components including a rosin and an epoxy resin, and various known rosins can be used. The rosins may be used alone or in combination of two or more, and the epoxy resins may be used alone or in combination of two or more.

[0023] (rosins) The rosins are not particularly limited, and various known rosins can be used, such as natural rosin, purified rosin (hereinafter, natural rosin and purified rosin are collectively referred to as unmodified rosin), hydrogenated rosin, and disproportionated rosin.

[0024] Examples of the natural rosin include natural rosins (gum rosin, tall oil rosin, wood rosin) derived from Masson pine (Pinus massoniana), Slash pine (Pinus elliottii), Merkusii pine (Pinus merkusii), Caribbean pine (Pinus caribaea), Sibo pine (Pinus kesiya), Loblolly pine (Pinus taeda), and Great King pine (Pinus palustris).

[0025] The purified rosin can be obtained using various known methods. Specifically, it can be obtained using various known purification methods, such as distillation, extraction, recrystallization, and adsorption. Examples of distillation methods include distilling the natural rosin at a temperature of approximately 200 to 300°C under a reduced pressure of approximately 0.01 to 3 kPa. Examples of extraction methods include dissolving the natural rosin in an alkaline aqueous solution, extracting the insoluble unsaponifiable matter with various organic solvents, and then neutralizing the aqueous layer. Examples of recrystallization methods include dissolving the natural rosin in an organic solvent as a good solvent, distilling off the solvent to obtain a concentrated solution, and then adding an organic solvent as a poor solvent. Examples of good solvents include aromatic hydrocarbon solvents such as benzene, toluene, and xylene, chlorinated hydrocarbon solvents such as chloroform, lower alcohols, ketones such as acetone, and acetate esters such as ethyl acetate. Examples of poor solvents include n-hexane, n-heptane, cyclohexane, and isooctane. The adsorption method may involve contacting the natural rosin in a molten state or in a solution state obtained by dissolving the natural rosin in an organic solvent with a porous adsorbent, such as activated carbon, metal oxides such as alumina, zirconia, silica, molecular sieves, zeolites, and microporous clay.

[0026] The purified rosin may be further subjected to the disproportionation and hydrogenation procedures described below, either singly or in combination of two or more thereof.

[0027] The hydrogenated rosin can be obtained by various known methods. Specifically, for example, the unmodified rosin can be reacted (hydrogenated) by heating under hydrogen pressure in the presence of a hydrogenation catalyst. Various known hydrogenation catalysts, such as supported catalysts and metal powders, can be used. Supported catalysts include palladium-carbon, rhodium-carbon, ruthenium-carbon, and platinum-carbon, while metal powders include nickel and platinum. The amount of the catalyst used is typically about 0.01 to 5 parts by mass, preferably about 0.01 to 2 parts by mass, per 100 parts by mass of the rosin used as the raw material. The hydrogen pressure is about 2 to 20 MPa, preferably about 5 to 20 MPa, and the reaction temperature is about 100 to 300°C, preferably about 150 to 300°C.

[0028] The hydrogenation may be carried out, if necessary, with the unmodified rosin dissolved in a solvent. The solvent used is not particularly limited, provided it is inert to the reaction and readily dissolves the raw materials and products. Specifically, for example, cyclohexane, n-hexane, n-heptane, decalin, tetrahydrofuran, dioxane, etc., can be used alone or in combination of two or more. The amount of solvent used is not particularly limited, but it is usually sufficient to use the solvent so that the solids content is 10% by mass or more, preferably in the range of about 10 to 70% by mass, relative to the unmodified rosin.

[0029] Furthermore, the hydrogenated rosin obtained may be further subjected to the above-mentioned purification, hydrogenation and disproportionation described below, either alone or in combination of two or more thereof.

[0030] The disproportionated rosin can be obtained by various known methods. Specifically, for example, the unmodified rosin can be reacted (disproportionated) by heating in the presence of a disproportionation catalyst. Examples of disproportionation catalysts include supported catalysts such as palladium-carbon, rhodium-carbon, and platinum-carbon; metal powders such as nickel and platinum; and iodides such as iodine and iron iodide. The amount of the catalyst used is typically about 0.01 to 5 parts by mass, preferably about 0.01 to 1 part by mass, per 100 parts by mass of the rosin used as a raw material. The reaction temperature is about 100 to 300°C, preferably about 150 to 290°C.

[0031] The disproportionated rosin may be further subjected to the purification and hydrogenation procedures either alone or in combination of two or more thereof.

[0032] Furthermore, for the purpose of improving color tone, the purified rosin, hydrogenated rosin, and disproportionated rosin may be further subjected to a dehydrogenation treatment. The dehydrogenation treatment is not particularly limited, and ordinary conditions can be used. For example, the dehydrogenation treatment may be carried out by subjecting the purified rosin, hydrogenated rosin, or disproportionated rosin to a dehydrogenation catalyst in a sealed container at an initial hydrogen pressure of 10 kg / cm. 2 less than 5 kg / cm 2 The dehydrogenation catalyst is generally less than 100°C, and the reaction temperature is about 100 to 300°C, with a lower limit of 200°C and an upper limit of 280°C. There are no particular limitations on the dehydrogenation catalyst, and various known catalysts can be used. Preferred examples include palladium-, rhodium-, and platinum-based catalysts, which are typically used supported on a carrier such as silica or carbon. The amount of the catalyst used is typically about 0.01 to 5% by weight, with a lower limit of 0.05% by weight and an upper limit of 3% by weight, based on the purified rosin, hydrogenated rosin, or disproportionated rosin.

[0033] (epoxy resin) The epoxy resin is not particularly limited, and various known epoxy resins can be used. Examples of the epoxy resin include bisphenol-type epoxy resins, novolac-type epoxy resins, resorcinol-type epoxy resins, phenol aralkyl-type epoxy resins, naphthol aralkyl-type epoxy resins, aliphatic polyepoxy compounds, alicyclic epoxy compounds, glycidylamine-type epoxy compounds, glycidyl ester-type epoxy compounds, monoepoxy compounds, naphthalene-type epoxy compounds, biphenyl-type epoxy compounds, epoxidized polybutadiene, epoxidized styrene-butadiene-styrene block copolymers, epoxy group-containing polyester resins, epoxy group-containing polyurethane resins, epoxy group-containing acrylic resins, stilbene-type epoxy compounds, triazine-type epoxy compounds, fluorene-type epoxy compounds, triphenolmethane-type epoxy compounds, alkyl-modified triphenolmethane-type epoxy compounds, dicyclopentadiene-type epoxy compounds, aryl alkylene-type epoxy compounds, trihydroxybiphenyl triglycidyl ether, and 1,1,2,2-tetra(4-hydroxyphenyl)ethane tetraglycidyl ether.

[0034] Examples of the bisphenol type epoxy resin include bisphenol A type epoxy resin, bisphenol E type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AD ​​type epoxy resin, hydrogenated bisphenol A type epoxy resin, hydrogenated bisphenol F type epoxy resin, hydrogenated bisphenol AD ​​type epoxy resin, tetrabromobisphenol A type epoxy resin, 3,3',5,5'-tetramethyl-4,4'-dihydroxybiphenyl diglycidyl ether, and 2,2-bis(4-(β-hydroxypropoxy)phenyl)propane diglycidyl ether.

[0035] Examples of the novolac epoxy resin include cresol novolac epoxy resin, phenol novolac epoxy resin, α-naphthol novolac epoxy resin, bisphenol A novolac epoxy resin, and brominated phenol novolac epoxy resin.

[0036] Examples of the aliphatic polyepoxy compound include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl ether, trimethylolpropane diglycidyl ether, trimethylolpropane triglycidyl ether, diglycerol triglycidyl ether, sorbitol tetraglycidyl ether, and diglycidyl ether.

[0037] Examples of the alicyclic epoxy compound include 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate, 2-(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexane-meta-dioxane, bis(3,4-epoxycyclohexylmethyl)adipate, bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, 3,4-epoxy-6-methylcyclohexyl-3',4'-epoxy-6'-methylcyclohexanecarboxylate, methylenebis(3,4-epoxycyclohexane), dicyclopentadiene diepoxide, ethylene glycol di(3,4-epoxycyclohexylmethyl)ether, ethylenebis(3,4-epoxycyclohexanecarboxylate), lactone-modified 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate, and 2,2-bis(4-hydroxycyclohexyl)propane diglycidyl ether.

[0038] Examples of the glycidylamine type epoxy compound include tetraglycidyldiaminodiphenylmethane, triglycidyl paraaminophenol, triglycidyl meta-aminophenol, and tetraglycidyl meta-xylylenediamine.

[0039] Examples of the glycidyl ester type epoxy compound include diglycidyl phthalate, diglycidyl hexahydrophthalate, diglycidyl tetrahydrophthalate, and triglycidyl trimellitate.

[0040] The weight-average molecular weight (Mw) of the epoxy resin is not particularly limited. Examples of the weight-average molecular weight of the epoxy resin include 3,000, 2,900, 2,800, 2,700, 2,600, 2,500, 2,400, 2,300, 2,200, 2,100, 2,000, 1,900, 1,800, 1,700, 1,600, 1,500, 1,400, 1,300, 1,200, 1,100, 1,000, 900, 800, 700, 600, and 500. The weight-average molecular weight of the epoxy resin is preferably about 500 to 3,000, and more preferably about 500 to 2,500, from the viewpoint of improving the holding power and adhesive strength of the pressure-sensitive adhesive. The weight average molecular weight is a polystyrene equivalent value determined by gel permeation chromatography (GPC).

[0041] The reaction components may include alcohols in addition to the rosins and epoxy resins.

[0042] The alcohols are not particularly limited, and examples thereof include dihydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, dimer diol, bisphenol A, and bisphenol F; trihydric alcohols such as glycerin, trimethylolethane, and trimethylolpropane; tetrahydric alcohols such as pentaerythritol and diglycerin; and hexahydric alcohols such as dipentaerythritol. Among these, polyhydric alcohols having three or more hydroxyl groups are preferred, and glycerin, pentaerythritol, diglycerin, and dipentaerythritol are particularly preferred. The alcohols may be used alone or in combination of two or more.

[0043] The method for producing the rosin polyol is not particularly limited, and various known methods can be used. Specific examples include a method in which the rosin, the epoxy resin, and, if necessary, the alcohol are subjected to a ring-opening addition reaction at 120 to 300°C in the presence or absence of a catalyst under a nitrogen stream.

[0044] Examples of the catalyst include amine catalysts such as trimethylamine, triethylamine, tributylamine, benzyldimethylamine, pyridine, and 2-methylimidazole; quaternary ammonium salts such as benzyltrimethylammonium chloride; Lewis acids; boric acid esters; organometallic compounds; organometallic salts; trialkylphosphines; and triarylphosphines.

[0045] In the ring-opening addition reaction, a solvent may be used as needed. The solvent is not particularly limited, but may be any solvent that is inert to the reaction and easily dissolves the raw materials and products. Specific examples include aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as n-hexane; and alicyclic hydrocarbons such as cyclohexane, methylcyclohexane, and ethylcyclohexane.

[0046] The amounts of the rosins and epoxy resins used are not particularly limited, but typically, the equivalent ratio of OH groups in the epoxy resin (total of epoxy groups and OH groups present in the epoxy resin) to COOH groups in the rosins is in the range of about 0.8 to 22, preferably about 0.8 to 10, where one epoxy group in the epoxy resin corresponds to two OH groups.

[0047] (Physical properties of rosin polyol) Examples of the weight-average molecular weight of the rosin polyol include 3,500, 3,400, 3,300, 3,200, 3,100, 3,000, 2,900, 2,800, 2,700, 2,600, 2,500, 2,400, 2,300, 2,200, 2,100, 2,000, 1,900, 1,800, 1,700, 1,600, and 1,500. The weight-average molecular weight is a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

[0048] The weight-average molecular weight of the rosin polyol is preferably 1,500 to 3,500. When the weight-average molecular weight of the rosin polyol is 1,500 to 3,500, the compatibility of the rosin polyol with the base polymer of the pressure-sensitive adhesive is good, and the compatibility with the acrylic polymer in particular is good, so that the pressure-sensitive adhesive has an excellent balance between adhesive strength and holding power.

[0049] If the weight-average molecular weight of the rosin polyol is less than 1,500, the cohesive strength of the adhesive decreases, tending to reduce the adhesive strength of the adhesive. If the weight-average molecular weight of the rosin polyol is more than 3,500, the compatibility of the rosin polyol with the base polymer of the adhesive decreases, particularly with the acrylic polymer, and therefore the effect of the tackifier resin does not fully manifest, and adhesive performance tends to decrease. Furthermore, if the weight-average molecular weight of the rosin polyol is more than 3,500, the compatibility of the rosin polyol with the acrylic monomers and acrylic oligomers of the active energy ray-curable acrylic adhesive also decreases, tending to reduce the effect of the tackifier resin, and adhesive performance tends to decrease.

[0050] The weight average molecular weight of the rosin polyol is more preferably about 1,500 to 3,100, and particularly preferably about 1,500 to 2,500, in order to provide an excellent balance between holding power and adhesive power in the pressure-sensitive adhesive.

[0051] The rosin polyol is not particularly limited in terms of its physical properties other than its weight-average molecular weight. Examples of the acid value (mgKOH / g) of the rosin polyol include 10 mgKOH / g, 9 mgKOH / g, 8 mgKOH / g, 7 mgKOH / g, 6 mgKOH / g, 5 mgKOH / g, 4 mgKOH / g, 3 mgKOH / g, 2 mgKOH / g, 1 mgKOH / g, 0.9 mgKOH / g, 0.8 mgKOH / g, 0.7 mgKOH / g, 0.6 mgKOH / g, 0.5 mgKOH / g, 0.4 mgKOH / g, 0.3 mgKOH / g, 0.2 mgKOH / g, and 0.1 mgKOH / g. The acid value of the rosin polyol is preferably about 0.1 to 10 mgKOH / g from the viewpoint of reducing the corrosiveness of the pressure-sensitive adhesive to the adherend, more preferably about 0.1 to 3 mgKOH / g from the same viewpoint, and particularly preferably about 0.1 to 1 mgKOH / g from the same viewpoint. In this specification, the acid value is a value measured in accordance with JIS K0070.

[0052] Examples of the hydroxyl value (mgKOH / g) of the rosin polyol include 200 mgKOH / g, 195 mgKOH / g, 190 mgKOH / g, 185 mgKOH / g, 180 mgKOH / g, 175 mgKOH / g, 170 mgKOH / g, 165 mgKOH / g, 160 mgKOH / g, 155 mgKOH / g, 150 mgKOH / g, 145 mgKOH / g, 140 mgKOH / g, 135 mgKOH / g, and 130 mgKOH / g. The hydroxyl value of the rosin polyol is preferably 130 mgKOH / g or more from the viewpoint of excellent compatibility between the rosin polyol and the base polymer of the pressure-sensitive adhesive and improving the adhesion of the pressure-sensitive adhesive to an adherend, more preferably about 130 to 200 mgKOH / g from the same viewpoint, still more preferably about 130 to 180 mgKOH / g from the same viewpoint, and particularly preferably about 135 to 160 mgKOH / g from the same viewpoint. Note that in this specification, the hydroxyl value is a value measured in accordance with JIS K0070.

[0053] Examples of the softening point (°C) of the rosin polyol include 150°C, 145°C, 140°C, 135°C, 130°C, 125°C, 120°C, 115°C, 110°C, 105°C, 100°C, 95°C, 90°C, 85°C, and 80°C. The softening point of the rosin polyol is preferably about 80 to 150°C from the viewpoint of improving the holding power of the pressure-sensitive adhesive, and more preferably about 90 to 120°C from the same viewpoint. In this specification, the softening point is a value measured by the ring and ball method according to JIS K 5902.

[0054] Examples of the color tone of the rosin resin include 400 Hazen, 350 Hazen, 300 Hazen, 250 Hazen, 200 Hazen, 150 Hazen, 100 Hazen, 95 Hazen, 90 Hazen, 85 Hazen, 80 Hazen, 75 Hazen, 70 Hazen, 65 Hazen, 60 Hazen, 55 Hazen, 50 Hazen, 45 Hazen, 40 Hazen, 35 Hazen, 30 Hazen, 25 Hazen, 20 Hazen, 15 Hazen, 10 Hazen, and 5 Hazen. The color tone of the rosin polyol is preferably 5 Gardner or less, more preferably about 10 to 400 Hazen, and particularly preferably about 10 to 200 Hazen, in terms of excellent appearance of the acrylic pressure-sensitive adhesive. In this specification, the color tone is measured in accordance with JIS K 0071-1 for Hazen units and in accordance with JIS K 0071-2 for Gardner units.

[0055] (additives) The rosin polyol may contain various known additives as needed, as long as they do not impair the effects of the present invention. Examples of additives include dehydrating agents, weathering agents, antioxidants, ultraviolet absorbers, heat stabilizers, and light stabilizers. The additives may be used alone or in combination of two or more.

[0056] [Tackifier] The tackifier of the present invention is not particularly limited as long as it is a tackifier containing the above-mentioned rosin polyol, and various known tackifiers can be used. When used in pressure-sensitive adhesives (including pressure-sensitive adhesive compositions described below), the tackifier improves the adhesive strength of the pressure-sensitive adhesive.

[0057] The tackifier may contain various known additives as needed, as long as the effects of the present invention are not impaired. Examples of additives include dehydrating agents, weathering agents, antioxidants, UV absorbers, heat stabilizers, and light stabilizers. The additives may be used alone or in combination of two or more. The content of the additives is not particularly limited, but is preferably 0.1 to 10 parts by mass per 100 parts by mass of the rosin polyol.

[0058] The tackifier is preferably used in pressure-sensitive adhesives containing an acrylic polymer as a base polymer (acrylic pressure-sensitive adhesives) in order to further improve the adhesive strength and holding power of the pressure-sensitive adhesives. Also, the tackifier is preferably used in active energy ray-curable acrylic pressure-sensitive adhesive compositions in order to further improve the adhesive strength and holding power of the pressure-sensitive adhesives.

[0059] [Adhesive / adhesive composition] The pressure-sensitive adhesive composition of the present invention is not particularly limited as long as it is a pressure-sensitive adhesive composition containing the above-mentioned rosin polyol (or the above-mentioned tackifier). The above-mentioned rosin polyols may be used alone or in combination of two or more. In this specification, the term "pressure-sensitive adhesive" clearly includes either or both of a pressure-sensitive adhesive and an adhesive.

[0060] The pressure-sensitive adhesive composition may be, for example, a composition containing the rosin polyol and a base polymer.

[0061] Examples of the base polymer include acrylic polymers, synthetic rubber elastomers, and olefin polymers. The base polymers may be used alone or in combination of two or more. The base polymer may further contain, as needed, a crosslinking agent, a filler, a release modifier, a plasticizer, a softener, a colorant (pigment, dye, etc.), a surfactant, an antistatic agent, an antioxidant, an ultraviolet absorber, an antioxidant, a light stabilizer, etc.

[0062] (acrylic polymer) The acrylic polymer may be one generally used in various acrylic pressure-sensitive adhesives, such as a polymer of a monomer component containing alkyl(meth)acrylate. The acrylic polymer may be produced by any of various known polymerization methods, such as a method of radically polymerizing the monomer component in the presence of a polymerization initiator. Examples of the polymerization method include solution polymerization, suspension polymerization, and bulk polymerization. The acrylic polymer may be used alone or in combination of two or more.

[0063] In this specification, "(meth)acrylic" means "at least one selected from the group consisting of acrylic and methacrylic." Similarly, "(meth)acrylate" means "at least one selected from the group consisting of acrylate and methacrylate," and "(meth)acryloyl group" means "at least one selected from the group consisting of acryloyl group and methacryloyl group."

[0064] Examples of the alkyl(meth)acrylate include methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, isopropyl(meth)acrylate, n-butyl(meth)acrylate, isobutyl(meth)acrylate, s-butyl(meth)acrylate, pentyl(meth)acrylate, isopentyl(meth)acrylate, hexyl(meth)acrylate, heptyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, octyl(meth)acrylate, and isooctyl(meth)acrylate. Examples of alkyl (meth)acrylates include acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate. These alkyl (meth)acrylates can be used alone or in combination of two or more.

[0065] The monomer components in the acrylic polymer may further include other monomers copolymerizable with the alkyl(meth)acrylate, such as carboxyl group-containing monomers, hydroxyl group-containing monomers, amide group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, cyano group-containing monomers, keto group-containing monomers, monomers having a nitrogen atom-containing ring, alkoxysilyl group-containing monomers, (meth)acrylates having an alicyclic structure, (meth)acrylates having an aromatic structure, and polyfunctional monomers.

[0066] Examples of the carboxyl group-containing monomer include ethylenically unsaturated monocarboxylic acids such as acrylic acid (AA), methacrylic acid (MAA), and crotonic acid; and ethylenically unsaturated dicarboxylic acids such as maleic acid, itaconic acid, and citraconic acid, and their anhydrides (maleic anhydride, itaconic anhydride, etc.).

[0067] Examples of the hydroxyl group-containing monomer include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylate; and unsaturated alcohols such as vinyl alcohol and allyl alcohol.

[0068] Examples of the amide group-containing monomer include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-butyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methylolpropane(meth)acrylamide, N-methoxymethyl(meth)acrylamide, and N-butoxymethyl(meth)acrylamide.

[0069] Examples of the amino group-containing monomer include aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and t-butylaminoethyl (meth)acrylate.

[0070] Examples of the epoxy group-containing monomer include glycidyl (meth)acrylate, methyl glycidyl (meth)acrylate, and allyl glycidyl ether. Examples of the cyano group-containing monomer include acrylonitrile and methacrylonitrile. Examples of the keto group-containing monomer include diacetone (meth)acrylamide, diacetone (meth)acrylate, vinyl methyl ketone, vinyl ethyl ketone, allyl acetoacetate, and vinyl acetoacetate.

[0071] Examples of the monomer having a nitrogen atom-containing ring include N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, and N-(meth)acryloylmorpholine.

[0072] Examples of the alkoxysilyl group-containing monomer include 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, and 3-(meth)acryloxypropylmethyldiethoxysilane.

[0073] Examples of the (meth)acrylate having an alicyclic structure include cyclohexyl (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, 1-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, and 2-ethyl-2-adamantyl (meth)acrylate.

[0074] Examples of the (meth)acrylate having an aromatic structure include aryl(meth)acrylate (e.g., phenyl(meth)acrylate), aryloxyalkyl(meth)acrylate (e.g., phenoxyethyl(meth)acrylate), and arylalkyl(meth)acrylate (e.g., benzyl(meth)acrylate).

[0075] Examples of the polyfunctional monomer include 1,6-hexanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, glycerin di(meth)acrylate, epoxy acrylate, divinylbenzene, butyl di(meth)acrylate, and hexyl di(meth)acrylate.

[0076] The content of other monomers copolymerizable with alkyl (meth)acrylate in the above monomer component is not particularly limited, but is preferably about 40% by mass or less relative to 100% by mass of the above monomer component.

[0077] The monomer components may further include vinyl ester monomers such as vinyl acetate and vinyl propionate; aromatic vinyl compounds such as styrene, substituted styrenes (such as α-methylstyrene) and vinyltoluene; olefin monomers such as ethylene, propylene, isoprene, butadiene and isobutylene; chlorine-containing monomers such as vinyl chloride and vinylidene chloride; isocyanate group-containing monomers such as 2-(meth)acryloyloxyethyl isocyanate; alkoxy group-containing monomers such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate; vinyl ether monomers such as methyl vinyl ether and ethyl vinyl ether. The content of these monomers is not particularly limited, but is preferably about 10% by mass or less relative to 100% by mass of the monomer components.

[0078] The polymerization initiator is not particularly limited, and examples thereof include azo-based initiators such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylpropionamidine) disulfate, 2,2'-azobis(2-methylpropionamidine) dihydrochloride, 2,2'-azobis(2-amidinopropane) dihydrochloride, 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] hydrate, 2,2'-azobis(N,N'-dimethyleneisobutylamidine), and 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride; 1,1-bis(t-hexylperoxy)-3,3,5-trimethylammonium bromide; Examples of the polymerization initiator include peroxide initiators such as ethylcyclohexane, t-hexylperoxypivalate, t-butylperoxypivalate, 2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, benzoyl peroxide, t-butyl hydroperoxide, and hydrogen peroxide; and persulfate initiators such as potassium persulfate and ammonium persulfate. The polymerization initiators may be used alone or in combination of two or more.

[0079] The weight-average molecular weight (Mw) of the acrylic polymer is not particularly limited, but is usually in the range of about 100,000 to 5,000,000. From the viewpoint of improving adhesive properties, the weight-average molecular weight (Mw) of the acrylic polymer is preferably 1,500,000 or less, more preferably 1,000,000 or less, and from the viewpoint of cohesion properties, etc., it is preferably 200,000 or more, more preferably 300,000 or more. In this specification, the weight-average molecular weight refers to a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

[0080] When the base polymer contains the acrylic polymer, the content of the rosin polyol in the pressure-sensitive adhesive composition is not particularly limited. The content of the rosin polyol in the pressure-sensitive adhesive composition, converted into solid content, can be, for example, 40 parts by mass, 39 parts by mass, 38 parts by mass, 37 parts by mass, 36 parts by mass, 35 parts by mass, 34 parts by mass, 33 parts by mass, 32 parts by mass, 31 parts by mass, 30 parts by mass, 29 parts by mass, 28 parts by mass, 27 parts by mass, 26 parts by mass, 25 parts by mass, 24 parts by mass, 23 parts by mass, 22 parts by mass, 21 parts by mass, 20 parts by mass, 19 parts by mass, 18 parts by mass, 17 parts by mass, 16 parts by mass, 15 parts by mass, 14 parts by mass, 13 parts by mass, 12 parts by mass, 11 parts by mass, 10 parts by mass, 9 parts by mass, 8 parts by mass, 7 parts by mass, 6 parts by mass, 5 parts by mass, 4 parts by mass, 3 parts by mass, 2 parts by mass, and the like, relative to 100 parts by mass of the acrylic polymer. When the base polymer contains the acrylic polymer, the content of the rosin polyol in the pressure-sensitive adhesive composition is preferably about 2 to 40 parts by mass, converted into a solid content, relative to 100 parts by mass of the acrylic polymer, since the effect of modification by the rosin polyol can be sufficiently exhibited and the adhesive strength of the pressure-sensitive adhesive can be further increased.

[0081] (synthetic rubber elastomer) As the synthetic rubber elastomer, various known synthetic rubber elastomers used in pressure-sensitive adhesive compositions can be used. The synthetic rubber elastomers may be used alone or in combination of two or more.

[0082] Examples of the synthetic rubber elastomer include polyisoprene, styrene-butadiene rubber (SBR), styrene-isoprene (SI) rubber, styrene-isoprene-styrene block copolymer (SIS) rubber, styrene-butadiene-styrene block copolymer (SBS) rubber, styrene-ethylene-butylene-styrene block copolymer (SEBS) rubber, styrene-ethylene-propylene-styrene block copolymer (SEPS) rubber, styrene-ethylene-propylene block copolymer (SEP) rubber, reclaimed rubber, butyl rubber, polyisobutylene, styrene-butadiene-vinylpyridine rubber, polybutadiene, methyl methacrylate-butadiene rubber, acrylonitrile-butadiene rubber (NBR), and polychloroprene (CR).

[0083] When the base polymer contains the synthetic rubber elastomer, the content of the rosin polyol in the pressure-sensitive adhesive composition is not particularly limited. The content of the rosin polyol in the pressure-sensitive adhesive composition, in terms of solid content, can be, for example, 210 parts by mass, 205 parts by mass, 200 parts by mass, 195 parts by mass, 190 parts by mass, 185 parts by mass, 180 parts by mass, 175 parts by mass, 170 parts by mass, 165 parts by mass, 160 parts by mass, 155 parts by mass, 150 parts by mass, 145 parts by mass, 140 parts by mass, or the like, relative to 100 parts by mass of the synthetic rubber elastomer. parts by mass, 135 parts by mass, 130 parts by mass, 125 parts by mass, 120 parts by mass, 115 parts by mass, 110 parts by mass, 105 parts by mass, 100 parts by mass, 95 parts by mass, 90 parts by mass, 85 parts by mass, 80 parts by mass, 75 parts by mass, 70 parts by mass, 65 parts by mass, 60 parts by mass, 55 parts by mass, 50 parts by mass, 45 parts by mass, 40 parts by mass, 35 parts by mass, 30 parts by mass, 25 parts by mass, 20 parts by mass, 15 parts by mass, etc. When the base polymer contains the synthetic rubber-based elastomer, the content of the rosin polyol in the pressure-sensitive adhesive composition is preferably about 15 to 210 parts by mass, converted into solid content, relative to 100 parts by mass of the synthetic rubber-based elastomer, since the effect of modification by the rosin polyol can be fully exhibited and the adhesive strength of the pressure-sensitive adhesive can be further increased.

[0084] (olefin polymer) The olefin polymer is not particularly limited as long as it is a polymer of a monomer component containing various olefins, and various known polymers can be used. Examples of the olefin polymer include an olefin homopolymer, which is a homopolymer of various olefins, and an olefin copolymer, which is a copolymer of various olefins with a copolymerizable monomer. The olefin polymer may be used alone or in combination of two or more.

[0085] Examples of the olefins include ethylene, propylene, butene, butylene, isoprene, pentene, pentadiene, octene, isooctene, various isomers of hexene and hexadiene, various isomers of heptene and heptadiene, various α-olefins, and cyclic olefins such as cyclopentene, cyclohexene, norbornene, and dicyclopentadienyl. The olefins may be used alone or in combination of two or more.

[0086] Examples of the monomer copolymerizable with the olefins include vinyl acetate and the (meth)acrylic acid esters. The copolymerizable monomer is preferably vinyl acetate. The copolymerizable monomers may be used alone or in combination of two or more.

[0087] The amount of the copolymerizable monomer used in the olefin copolymer is not particularly limited, but is preferably in the range of about 20 to 45% by mass relative to 100% by mass of the olefin copolymer.

[0088] Examples of the olefin homopolymer include polyethylene, polypropylene, ethylene-α-olefin copolymer, amorphous atactic polypropylene, etc. Examples of the olefin copolymer include ethylene acrylic acid copolymer (EAA), ethylene methacrylic acid copolymer (EMAA), ethylene vinyl acetate copolymer (EVA), ethylene ethyl acrylate copolymer (EEA), ethylene methyl acrylate copolymer (EMA), ethylene methyl methacrylate copolymer (EMMA), etc. Of the olefin copolymer, ethylene vinyl acetate copolymer (EVA) is preferred.

[0089] When the base polymer contains the olefin-based polymer, the content of the rosin polyol in the pressure-sensitive adhesive composition is not particularly limited. Examples of the content of the rosin polyol in the pressure-sensitive adhesive composition, calculated as solid content, relative to 100 parts by mass of the olefin-based polymer include 150 parts by mass, 145 parts by mass, 140 parts by mass, 135 parts by mass, 130 parts by mass, 125 parts by mass, 120 parts by mass, 115 parts by mass, 110 parts by mass, 105 parts by mass, 100 parts by mass, 95 parts by mass, 90 parts by mass, 85 parts by mass, 80 parts by mass, 75 parts by mass, 70 parts by mass, 65 parts by mass, 60 parts by mass, 55 parts by mass, and 50 parts by mass. When the base polymer contains the olefin-based polymer, the content of the rosin polyol in the pressure-sensitive adhesive composition is preferably about 50 to 150 parts by mass, converted into a solid content, relative to 100 parts by mass of the olefin-based polymer, since the effect of modification by the rosin polyol can be sufficiently exhibited and the adhesive strength of the pressure-sensitive adhesive can be further increased.

[0090] The pressure-sensitive adhesive composition is preferably an acrylic pressure-sensitive adhesive composition containing the acrylic polymer as the base polymer, because of the high effect of modification by the rosin polyol (or the tackifier). Furthermore, the acrylic pressure-sensitive adhesive composition contains the rosin polyol, and therefore has high adhesive strength, particularly to polar adherends such as glass and metal.

[0091] The above pressure-sensitive adhesive composition can be used in either a varnish type or a hot melt type.

[0092] When the pressure-sensitive adhesive composition is used as a varnish, various organic solvents can be used. The organic solvent is not particularly limited, but specific examples include toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, acetone, ethyl acetate, cyclohexane, methylcyclohexane, methanol, ethanol, propanol, isopropanol, and hexylene glycol. The amount of the organic solvent used is not particularly limited, but is usually about 100 to 500 parts by mass per 100 parts by mass of the base polymer.

[0093] When the pressure-sensitive adhesive composition is used as the hot melt type, the organic solvent that can be used in the varnish type is not particularly required.

[0094] The pressure-sensitive adhesive composition may contain various additives as needed, such as a crosslinking agent, oil, wax, a tackifier other than the above-mentioned tackifying resin, an antifoaming agent, a viscosity modifier, a filler, an antioxidant, a water-resistant agent, a film-forming aid, a preservative, a pH adjuster such as ammonia water or sodium bicarbonate, a leveling agent, a release adjuster, a plasticizer, a softener, a colorant (pigment, dye, etc.), a surfactant, an antistatic agent, an antioxidant, an ultraviolet absorber, an antioxidant, and a light stabilizer, as long as the desired properties are not impaired.

[0095] Examples of the crosslinking agent include an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, etc. The content of the crosslinking agent is not particularly limited, but is usually 10 parts by mass or less, and preferably about 0.01 to 1.0 part by mass, per 100 parts by mass of the base polymer.

[0096] Examples of the isocyanate-based crosslinking agent include lower aliphatic polyisocyanates such as 1,2-ethylene diisocyanate, 1,4-butylene diisocyanate, and 1,6-hexamethylene diisocyanate; alicyclic polyisocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, and hydrogenated xylene diisocyanate; aromatic polyisocyanates such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylene diisocyanate; and biuret, isocyanurate, allophanate, and adduct thereof, as well as complexes obtained by reacting two or more selected from the group consisting of biuret, isocyanurate, allophanate, and adduct.

[0097] Examples of the epoxy crosslinking agent include compounds having two or more epoxy groups in the molecule, such as bisphenol A epichlorohydrin-type epoxy resins, ethylene diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidylaniline, diamine glycidylamine, N,N,N',N'-tetraglycidyl-m-xylylenediamine, and 1,3-bis(N,N'-diamineglycidylaminomethyl)cyclohexane.

[0098] Examples of the oil include plasticized oils such as naphthenic oil, paraffinic oil, and aromatic oil, etc. Preferred oils include naphthenic process oil, paraffinic process oil, and liquid polybutene.

[0099] The content of the oil is not particularly limited, but is usually preferably about 4 to 200 parts by mass per 100 parts by mass of the base polymer.

[0100] Examples of the wax include animal-derived waxes such as beeswax, spermaceti, and shellac wax, plant-derived waxes such as carnauba wax, Japan wax, rice bran wax, and candelilla wax, petroleum-derived waxes such as paraffin wax and microcrystalline wax, synthetic waxes such as Fischer-Tropsch wax and low-molecular-weight polyethylene wax, and mineral-derived waxes such as montan wax and ozokerite. The waxes may be used alone or in combination.

[0101] The content of the wax is not particularly limited, but is usually preferably about 10 to 100 parts by mass per 100 parts by mass of the base polymer.

[0102] The pressure-sensitive adhesive composition can be obtained by mixing the rosin polyol, the base polymer, and, if necessary, the organic solvent and the additives. The mixing method is not particularly limited, and various known methods can be used.

[0103] [Actual energy ray curable acrylic adhesive composition] The pressure-sensitive adhesive composition of the present invention may be an active energy ray-curable acrylic pressure-sensitive adhesive composition containing the rosin polyol (or the tackifier), an acrylic monomer, an acrylic oligomer, and a photopolymerization initiator.

[0104] Examples of the acrylic monomer include the monomer components that are raw materials for the acrylic polymer.

[0105] The acrylic oligomer is a polymerizable polymer (macromonomer) containing a (meth)acryloyl group, and any known raw material can be used without particular limitation as long as it is a raw material that synthesizes a polymer by a curing reaction in a state where the degree of polymerization is relatively low, about 2 to 20. Specific examples include polyacryl(meth)acrylate, polyurethane(meth)acrylate, polyester(meth)acrylate, polyether(meth)acrylate, etc.

[0106] As the photopolymerization initiator, various known ones can be used without any particular limitation as long as they can be decomposed by active energy rays to generate radicals and initiate polymerization.Specific examples include 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-cyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 4-methylbenzophenone, etc. These can be used alone or in combination of two or more.

[0107] The content of each component in the active energy ray-curable acrylic pressure-sensitive adhesive composition is not particularly limited.

[0108] The content of the rosin polyol in the active energy ray-curable acrylic pressure-sensitive adhesive composition, in terms of solid content, relative to 100 parts by mass of the total of the acrylic monomer and the acrylic oligomer, may be, for example, 100 parts by mass, 95 parts by mass, 90 parts by mass, 85 parts by mass, 80 parts by mass, 75 parts by mass, 70 parts by mass, 65 parts by mass, 60 parts by mass, 55 parts by mass, 50 parts by mass, 45 parts by mass, 40 parts by mass, 35 parts by mass, 30 parts by mass, 25 parts by mass, 20 parts by mass, 15 parts by mass, 10 parts by mass, 9 parts by mass, 8 parts by mass, 7 parts by mass, 6 parts by mass, 5 parts by mass, 4 parts by mass, 3 parts by mass, 2 parts by mass, 1 part by mass, and the like. The content of the rosin polyol in the active energy ray-curable acrylic pressure-sensitive adhesive composition is preferably about 1 to 100 parts by mass, calculated as solid content, per 100 parts by mass of the total of the acrylic monomer and the acrylic oligomer, in order to further increase the adhesive strength of the pressure-sensitive adhesive.

[0109] The content of the photopolymerization initiator in the active energy ray-curable acrylic pressure-sensitive adhesive composition, in terms of solid content, can be, for example, 10 parts by mass, 9 parts by mass, 8 parts by mass, 7 parts by mass, 6 parts by mass, 5 parts by mass, 4 parts by mass, 3 parts by mass, 2 parts by mass, 1 part by mass, 0.9 parts by mass, 0.8 parts by mass, 0.7 parts by mass, 0.6 parts by mass, 0.5 parts by mass, 0.4 parts by mass, 0.3 parts by mass, 0.2 parts by mass, 0.1 parts by mass, etc. ...

[0110] The active energy ray-curable acrylic pressure-sensitive adhesive composition may contain various additives as needed, as long as the desired properties are not impaired. For example, the active energy ray-curable acrylic pressure-sensitive adhesive composition may contain additives such as the above-mentioned crosslinking agents, surface conditioners, surfactants, ultraviolet absorbers, antioxidants, light stabilizers, tackifiers other than the above-mentioned rosin polyols, plasticizers, inorganic fillers, silane coupling agents, colloidal silica, antifoaming agents, wetting agents, and rust inhibitors.

[0111] The active energy ray-curable acrylic pressure-sensitive adhesive composition can be obtained by mixing the rosin polyol (or the tackifier), the acrylic monomer, the acrylic oligomer, and the photopolymerization initiator, and, if necessary, the additives. The mixing method is not particularly limited, and various known methods can be used.

[0112] The active energy ray-curable acrylic pressure-sensitive adhesive composition contains the rosin polyol, and therefore has high adhesive strength, particularly to polar adherends such as glass and metal.

[0113] (Adhesive / bonding sheet) The adhesive / adhesive sheet of the present invention comprises a substrate and an adhesive layer made of the above-mentioned adhesive / adhesive composition. The adhesive / adhesive sheet of the present invention may be a substrate-attached adhesive sheet in which the adhesive / adhesive layer is provided on one or both sides of the substrate, or may be a substrate-less adhesive / adhesive sheet in which the adhesive / adhesive layer is supported on a release liner (which may also be understood as a substrate with a release surface). The concept of adhesive / adhesive sheet here may include those known as adhesive / adhesive tapes, adhesive / adhesive labels, adhesive / adhesive films, etc.

[0114] Examples of the substrate include polyolefin (polyethylene, polypropylene, ethylene-propylene copolymer, etc.) films, polyester (polyethylene terephthalate, etc.) films, vinyl chloride resin films, vinyl acetate resin films, polyimide resin films, polyamide resin films, fluorine-containing resin films, and other plastic films such as cellophane; paper (Japanese paper, kraft paper, glassine paper, fine paper, synthetic paper, top-coated paper, etc.); fabrics (woven fabrics and nonwoven fabrics) made from natural, semi-synthetic, or synthetic fibers, such as cotton fiber, staple fiber, Manila hemp, pulp, rayon, acetate fiber, polyester fiber, polyvinyl alcohol fiber, polyamide fiber, and polyolefin fiber, either alone or in combination; rubber sheets made from natural rubber, butyl rubber, etc.; foam sheets made from foams such as polyurethane foam and polychloroprene rubber foam; metal foils such as aluminum foil and copper foil; and composites thereof. The films may be either unstretched or stretched (uniaxially or biaxially stretched). The substrate may have a single layer structure or a laminate structure.

[0115] The base material may contain various additives, such as fillers (inorganic fillers, organic fillers, etc.), antioxidants, antioxidants, ultraviolet absorbers, lubricants, plasticizers, and colorants (pigments, dyes, etc.), as needed.

[0116] The surface of the substrate (particularly the surface on the polymer layer side) may be subjected to an appropriate known or conventional surface treatment, for example, a physical treatment such as corona discharge treatment or plasma treatment, or a chemical treatment such as an undercoat treatment or backside treatment.

[0117] The method for producing the pressure-sensitive adhesive sheet is not particularly limited, and various known methods can be employed.

[0118] Specifically, for example, the pressure-sensitive adhesive composition is first applied to one or both surfaces of a substrate to form a coating layer made of the pressure-sensitive adhesive composition. As the coating method, a known method can be applied, and examples thereof include a roll coater method, a comma coater method, a die coater method, a reverse coater method, a silk screen method, and a gravure coater method.

[0119] Next, when the pressure-sensitive adhesive composition is a pressure-sensitive adhesive composition containing the base polymer, the coating layer is heated or dried to form a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition. The heating or drying conditions can be appropriately set depending on the thickness of the pressure-sensitive adhesive layer, and the temperature is, for example, 10 to 120°C, and the drying time is, for example, 0.1 to 10 hours. The thickness of the pressure-sensitive adhesive layer (thickness after drying) varies depending on the application, but is preferably 5 to 200 μm.

[0120] When the pressure-sensitive adhesive composition is the active energy ray-curable acrylic pressure-sensitive adhesive composition, the coating layer is irradiated with active energy rays to cure the composition, thereby forming a pressure-sensitive adhesive layer. The thickness of the pressure-sensitive adhesive layer (thickness after curing) varies depending on the application, but is usually about 10 to 1000 μm, preferably about 25 to 500 μm on average.

[0121] Examples of the active energy rays include ultraviolet rays and electron beams. When curing with ultraviolet rays, an ultraviolet irradiation device having a xenon lamp, high-pressure mercury lamp, metal halide lamp, or the like is used as a light source, and the light amount, light source arrangement, etc. are adjusted as necessary. When using a high-pressure mercury lamp, curing is preferably carried out at a conveying speed of about 5 to 50 m / min using one lamp with a light amount of 80 to 160 W / cm. On the other hand, when curing with electron beams, curing is preferably carried out at a conveying speed of 5 to 50 m / min using an electron beam accelerator with an acceleration voltage of 10 to 300 kV.

[0122] The pressure-sensitive adhesive sheet has a high adhesive strength and holding power because it includes a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition, and is therefore suitable as a structural bonding tape for applications requiring long-term adhesive strength, such as building materials and automobile interior components.

[0123] [Use as a tackifier] The rosin polyol can be used as a tackifier for pressure-sensitive adhesives. When the rosin polyol is used as a tackifier, the adhesive strength and holding power of the pressure-sensitive adhesive are improved. The pressure-sensitive adhesive is not particularly limited, and examples thereof include those mentioned above.

[0124] The rosin polyol is suitably used as a tackifier for an acrylic pressure-sensitive adhesive composition and an active energy ray-curable acrylic pressure-sensitive adhesive composition, since it further improves the adhesive strength and holding power of the pressure-sensitive adhesive.

[0125] The amount of the rosin polyol used as a tackifier in the acrylic pressure-sensitive adhesive composition is not particularly limited, and examples of the amount of the rosin polyol used, in terms of solid content, relative to 100 parts by mass of the acrylic polymer include 40 parts by mass, 39 parts by mass, 38 parts by mass, 37 parts by mass, 36 parts by mass, 35 parts by mass, 34 parts by mass, 33 parts by mass, 32 parts by mass, 31 parts by mass, 30 parts by mass, 29 parts by mass, 28 parts by mass, 27 parts by mass, 26 parts by mass, 25 parts by mass, 24 parts by mass, 23 parts by mass, 22 parts by mass, 21 parts by mass, 20 parts by mass, 19 parts by mass, 18 parts by mass, 17 parts by mass, 16 parts by mass, 15 parts by mass, 14 parts by mass, 13 parts by mass, 12 parts by mass, 11 parts by mass, 10 parts by mass, 9 parts by mass, 8 parts by mass, 7 parts by mass, 6 parts by mass, 5 parts by mass, 4 parts by mass, 3 parts by mass, and 2 parts by mass. The amount of the rosin polyol used is preferably about 2 to 40 parts by mass, calculated as solid content, per 100 parts by mass of the acrylic polymer, in order to further improve the adhesive strength and holding power of the acrylic pressure-sensitive adhesive composition.

[0126] The amount of the rosin polyol used as a tackifier in the active energy ray-curable acrylic pressure-sensitive adhesive composition is not particularly limited, and examples of the amount of the rosin polyol used, in terms of solid content, relative to 100 parts by mass of the total of the acrylic monomer and acrylic oligomer, include 100 parts by mass, 95 parts by mass, 90 parts by mass, 85 parts by mass, 80 parts by mass, 75 parts by mass, 70 parts by mass, 65 parts by mass, 60 parts by mass, 55 parts by mass, 50 parts by mass, 45 parts by mass, 40 parts by mass, 35 parts by mass, 30 parts by mass, 25 parts by mass, 20 parts by mass, 15 parts by mass, 10 parts by mass, 9 parts by mass, 8 parts by mass, 7 parts by mass, 6 parts by mass, 5 parts by mass, 4 parts by mass, 3 parts by mass, 2 parts by mass, 1 part by mass, and the like. The amount of the rosin polyol used as the tackifier is preferably about 1 to 100 parts by mass, calculated as solid content, per 100 parts by mass of the acrylic monomer and acrylic oligomer combined, in order to fully exhibit the effect of the modification by the tackifier. [Example]

[0127] The present invention will be described in more detail below by showing examples of the present invention. The examples are not limited to the examples. In the examples, "parts" and "%" respectively "Parts by mass" and "% by mass" are used.

[0128] [Production of rosin polyol] Example 1 A reactor equipped with a stirrer, a cooling tube, and a nitrogen inlet tube was charged with 100 parts of hydrogenated rosin and heated under a nitrogen stream until completely melted. 80 parts of bisphenol A polymer epoxy resin (weight average molecular weight 800) was then added with stirring, and 0.1 parts of 2-methylimidazole was added at 140°C. The mixture was allowed to react at 180°C for 3 hours, yielding a rosin polyol with a hydroxyl value of 139 mgKOH / g, a weight average molecular weight of 1,600, a softening point of 94°C, and an acid value of 0.6 mgKOH / g.

[0129] Example 2 A reactor equipped with a stirrer, a cooling tube, and a nitrogen inlet tube was charged with 100 parts of hydrogenated rosin and heated under a nitrogen stream until completely melted. 150 parts of bisphenol A-type polymer epoxy resin (weight average molecular weight 1,500) was then added with stirring, and 0.1 parts of 2-methylimidazole was added at 140°C. The mixture was allowed to react at 180°C for 3 hours, yielding a rosin polyol with a hydroxyl value of 150 mgKOH / g, a weight average molecular weight of 2,300, a softening point of 105°C, and an acid value of 0.1 mgKOH / g.

[0130] Example 3 A reactor equipped with a stirrer, a cooling tube, and a nitrogen inlet tube was charged with 100 parts of hydrogenated rosin and heated under a nitrogen stream until completely melted. 200 parts of bisphenol A-type polymer epoxy resin (weight average molecular weight: 2,300) was then added with stirring, and 0.1 parts of 2-methylimidazole was added at 140°C. The mixture was allowed to react at 180°C for 3 hours, yielding a rosin polyol with a hydroxyl value of 160 mgKOH / g, a weight average molecular weight of 3,100, a softening point of 107°C, and an acid value of 0.1 mgKOH / g.

[0131] Comparative Example 1 A reactor equipped with a stirrer, a cooling tube, and a nitrogen inlet tube was charged with 100 parts of hydrogenated rosin and heated under a nitrogen stream until completely melted. 180 parts of bisphenol A polymer epoxy resin (weight average molecular weight 1,500) was then added with stirring, and 0.1 parts of 2-methylimidazole was added at 140°C. The mixture was allowed to react at 180°C for 3 hours, yielding a rosin polyol with a hydroxyl value of 150 mgKOH / g, a weight average molecular weight of 3,600, a softening point of 110°C, and an acid value of 3.5 mgKOH / g.

[0132] Comparative Example 2 A reactor equipped with a stirrer, a cooling tube, and a nitrogen inlet tube was charged with 100 parts of hydrogenated rosin and heated under a nitrogen stream until completely melted. 280 parts of bisphenol A-type polymer epoxy resin (weight average molecular weight 3,700) was then added with stirring, and 0.1 parts of 2-methylimidazole was added at 140°C. The mixture was allowed to react at 180°C for 3 hours, yielding a rosin polyol with a hydroxyl value of 178 mgKOH / g, a weight average molecular weight of 4,500, a softening point of 114°C, and an acid value of 2.0 mgKOH / g.

[0133] Comparative Example 3 A reactor equipped with a stirrer, a cooling tube, and a nitrogen inlet tube was charged with 100 parts of polymerized rosin and heated under a nitrogen stream until completely melted. 21.1 parts of dipentaerythritol was then added with stirring, and the mixture was allowed to react at 280°C for 13 hours, yielding a polymerized rosin ester with a hydroxyl value of 148 mgKOH / g, a weight-average molecular weight of 3,250, a softening point of 157°C, and an acid value of 17.0 mgKOH / g.

[0134] (Measurement of hydroxyl value and acid value) The hydroxyl values ​​and acid values ​​of the rosin polyols of Examples 1 to 3 and Comparative Examples 1 and 2, the polymerized rosin ester of Comparative Example 3, and the commercially available rosin polyols described below were measured according to JIS K0070.

[0135] (Measurement of weight average molecular weight (Mw)) The weight-average molecular weights (Mw) of the rosin polyols of Examples 1 to 3 and Comparative Examples 1 and 2, the polymerized rosin ester of Comparative Example 3, and the commercially available rosin polyols described below were calculated as polystyrene equivalent values ​​by gel permeation chromatography (GPC) using a calibration curve of standard polystyrene. The GPC measurements were performed under the following conditions. The results are shown in Table 1. Analytical equipment: HLC-8320 (manufactured by Tosoh Corporation) Column: TSKgel Super HM-L x 3 Eluent: tetrahydrofuran Injection sample concentration: 5 mg / mL Flow rate: 0.6mL / min Injection volume: 40μL Column temperature: 40℃ Detector: RI

[0136] (Softening point measurement) The softening points of the rosin polyols of Examples 1 to 3 and Comparative Examples 1 and 2, the polymerized rosin ester of Comparative Example 3, and the commercially available rosin polyols described below were measured in accordance with JIS K 5902.

[0137] [Production of acrylic pressure-sensitive adhesive composition] Example 4 90 parts (solid content equivalent) of an acrylic polymer (manufactured by Soken Chemical & Engineering Co., Ltd., trade name "SK Dyne 1451", solid content 30%) and 10 parts of the rosin polyol of Example 1 were thoroughly kneaded, and then 0.3 parts of an isocyanate crosslinking agent (manufactured by Nippon Polyurethane Co., Ltd., trade name "Coronate L") was added to obtain an acrylic pressure-sensitive adhesive composition.

[0138] Examples 5 to 6 and Comparative Examples 4 to 5 and 8 An acrylic pressure-sensitive adhesive composition was obtained in the same manner as in Example 4, except that the rosin polyol in Example 1 was changed to the rosin polyols in Examples 2 and 3 and Comparative Examples 1 and 2, and the polymerized rosin ester in Comparative Example 3.

[0139] Comparative Example 6 An acrylic pressure-sensitive adhesive composition was obtained in the same manner as in Example 4, except that the rosin polyol in Example 1 was changed to a commercially available rosin polyol (manufactured by Arakawa Chemical Industries, Ltd., trade name "D-6011", hydroxyl value 120 mg KOH / g, weight average molecular weight 1,100, softening point 90°C, acid value 0.1 mg KOH / g) (hereinafter referred to as D-6011).

[0140] Comparative Example 7 An acrylic pressure-sensitive adhesive composition was obtained in the same manner as in Example 4, except that the rosin polyol in Example 1 was changed to a commercially available rosin polyol (manufactured by Arakawa Chemical Industries, Ltd., trade name "D-6250", hydroxyl value 35 mgKOH / g, weight average molecular weight 5,700, acid value 1.0 mgKOH / g) (hereinafter referred to as D-6250).

[0141] Reference example 1 An acrylic pressure-sensitive adhesive composition was obtained by adding 0.3 parts of an isocyanate crosslinking agent (manufactured by Nippon Polyurethane Co., Ltd., product name "Coronate L") to 100 parts (solid content equivalent) of an acrylic polymer (manufactured by Soken Chemical & Engineering Co., Ltd., product name "SK Dyne 1451", solid content 30%).

[0142] [Creating sample tapes] Using a dice-type applicator (manufactured by Daiyu Kizai Co., Ltd.), the above acrylic pressure-sensitive adhesive composition was applied to a polyester film (trade name "S-100", manufactured by Mitsubishi Chemical Corporation, thickness: 38 μm) to a thickness of about 35 μm, and then dried for 5 minutes in a circulating air dryer at 105°C to prepare a sample tape. The sample tape was then left to age for 1 week in a thermostatic chamber at 23°C and 50% RH, and then evaluated by the following test methods.

[0143] (Adhesive strength) The above sample tape was cut into a width of 25 mm, and the tape was laminated to a stainless steel plate by rolling a 2 kg roller back and forth once, and then left to stand for one day. A 180-degree peel test was then performed at a tensile speed of 300 mm / min and a temperature of 40°C to measure the adhesive strength (N / 25 mm). The results are shown in Table 1.

[0144] (holding force) The above sample tape was cut into a width of 25 mm and a length of 100 mm, and was laminated to a polyethylene plate by rolling a 2 kg roller back and forth once. Next, a 200 g load was applied to the end of the sample tape, and it was fixed so that it would peel at a 90° angle. The peel distance (mm / h) per 60 minutes was measured at 23°C. If the load dropped within 60 minutes, the peel distance was calculated using Equation 1. The results are shown in Table 1. The shorter the peel distance, the higher the holding power. Formula 1: Peel distance after 60 minutes (mm / h) = 100mm x 60 / drop time (min)

[0145] [Table 1]

[0146] [Production of active energy ray-curable acrylic adhesive composition] Example 7 To 25.0 parts of a urethane acrylate oligomer (weight average molecular weight 1,600, average functionality 2, manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "UA-160™"), 10.0 parts of dicyclopentenyloxyethyl methacrylate (manufactured by Resonac Corporation, trade name "FA-512M") as acrylic monomers, 8.0 parts of lauryl acrylate (LA, manufactured by Osaka Organic Chemical Industry Ltd.), and 5.0 parts of 4-hydroxybutyl acrylate (4-HBA, manufactured by Osaka Organic Chemical Industry Ltd.), 30.0 parts of the rosin polyol of Example 1, and 0.5 parts of Omnirad H TPO (manufactured by IGM Resins BV) and 1.5 parts of Omnirad 184 (manufactured by IGM Resins BV) as photoinitiators were added to obtain an active energy ray-curable acrylic pressure-sensitive adhesive composition.

[0147] Examples 8 to 9 and Comparative Examples 9 and 12 An acrylic pressure-sensitive adhesive composition was obtained in the same manner as in Example 7, except that the rosin polyol in Example 1 was changed to the rosin polyols in Examples 2 and 3 and Comparative Example 2, and the polymerized rosin ester in Comparative Example 3.

[0148] Comparative Example 10 An acrylic pressure-sensitive adhesive composition was obtained in the same manner as in Example 7, except that the rosin polyol in Example 1 was changed to D-6011.

[0149] Comparative Example 11 An acrylic pressure-sensitive adhesive composition was obtained in the same manner as in Example 7, except that the rosin polyol in Example 1 was changed to D-6250.

[0150] Reference example 2 An active energy ray-curable acrylic pressure-sensitive adhesive composition was obtained by adding 25.0 parts of a urethane acrylate oligomer (weight average molecular weight 1,600, average functionality 2, manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "UA-160™") to 10.0 parts of dicyclopentenyloxyethyl methacrylate (manufactured by Resonac Corporation, trade name "FA-512M") as acrylic monomers, 8.0 parts of lauryl acrylate (LA, manufactured by Osaka Organic Chemical Industry Ltd.), and 5.0 parts of 4-hydroxybutyl acrylate (4-HBA, manufactured by Osaka Organic Chemical Industry Ltd.), and 0.5 parts of Omnirad H TPO (manufactured by IGM Resins BV) and 1.5 parts of Omnirad 184 (manufactured by IGM Resins BV) as photoinitiators.

[0151] [Creating sample tapes] Using a dice-shaped applicator (manufactured by Daiyu Kizai Co., Ltd.), the above-mentioned active energy ray-curable acrylic pressure-sensitive adhesive composition was applied to a polyethylene terephthalate film (trade name "S-100", manufactured by Mitsubishi Chemical Corporation, thickness: 38 μm) to a thickness of about 150 μm, and then the film was irradiated with an ultraviolet ray irradiation device (UBT-080-7A / BM, manufactured by Multiply Co., Ltd.) with an integrated light dose of 300 mJ / cm. 2 So, 200mW / cm 2 The adhesive was cured by irradiation with strong ultraviolet light to prepare a sample tape.

[0152] (Adhesive strength) The above sample tape was cut into a width of 25 mm, and the tape was laminated to a glass plate by rolling a 2 kg roller back and forth once, and then left to stand for one day. A 180-degree peel test was then performed at a tensile speed of 300 mm / min and a temperature of 40°C to measure the adhesive strength (N / 25 mm). The results are shown in Table 2.

[0153] (holding force) The above sample tape was cut into a width of 25 mm and a length of 100 mm, and was laminated to a stainless steel plate by rolling a 2 kg roller back and forth once. Next, a 100 g load was applied to the end of the sample tape, and the tape was fixed so that it would peel at a 90° angle. The peel distance (cm / h) per 60 minutes was measured at 23°C. If the load dropped within 60 minutes, the peel distance was calculated using Equation 1. The results are shown in Table 2. The shorter the peel distance, the higher the holding power. Formula 1: Peel distance after 60 minutes (cm / h) = 10cm x 60 / fall time (min)

[0154] [Table 2]

[0155] The notes in Table 2 are as follows: *Since rosin polyol and polymerized rosin ester could not be dissolved in acrylic oligomer and acrylic monomer, an active energy ray-curable acrylic pressure-sensitive adhesive composition could not be produced.

Claims

1. The weight average molecular weight is 1,500 to 3,500, a rosin polyol having a hydroxyl value of 130 mgKOH / g or more; the rosin polyol is a reaction product of reaction components including rosins and epoxy resins, The weight average molecular weight of the epoxy resin is 500 to 3,000. Rosin polyol.

2. A tackifier comprising the rosin polyol of claim 1.

3. A pressure-sensitive adhesive composition comprising the rosin polyol according to claim 1.

4. An acrylic pressure-sensitive adhesive composition comprising the rosin polyol according to claim 1.

5. An active energy ray-curable acrylic pressure-sensitive adhesive composition comprising the rosin polyol according to claim 1.

6. 10. Use of the rosin polyol of claim 1 as a tackifier.

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