JP6703855B2 - Resin composition containing (meth)acrylic block copolymer, and pressure-sensitive adhesive obtained from the resin composition - Google Patents

Description

The present invention relates to a resin composition containing a (meth)acrylic block copolymer, and a pressure-sensitive adhesive obtained from the resin composition.

Since a resin composition containing a (meth)acrylic polymer has excellent weather resistance and adhesive/bonding properties, various studies have been conducted for adhesive/adhesive applications. For example, (meth)acrylic block copolymers are excellent in heat resistance, weather resistance, holding power (cohesive force), and the like, and therefore have been studied as adhesives for various applications (for example, See Patent Document 1.).

In order to improve the workability at the time of heating and melting by adjusting the viscosity to an appropriate level, the pressure-sensitive adhesive containing the (meth)acrylic block copolymer can balance the performance of the pressure-sensitive adhesive. It is common to add auxiliary components such as tackifying resin and plasticizer.

However, with conventional adhesives, there is room for improvement in compatibility between hot melt extrusion coating properties and holding power. Moreover, even if a plasticizer is included, no exudation of the plasticizer can be seen, which is economical. No excellent adhesive has yet been found.

JP, 2005-078281, A Japanese Patent Publication No. 7-025859 JP, 11-335432, A JP-A-6-093060

Therefore, an object of the present invention is to obtain a tacky adhesive which has a small shear rate dependence of viscosity, is excellent in hot melt extrusion coating property and holding power, and has little exudation of the plasticizer even when it contains the plasticizer. It is an object of the present invention to provide a resin composition that is capable of achieving excellent economical efficiency.

According to the present invention, the above objects are
[1] A resin composition comprising a component (I) containing a (meth)acrylic block copolymer (A) and a calcium carbonate powder (II),
(I) The content of the (meth)acrylic block copolymer (A) in the component (I) is 30% by mass or more,
(Ii) The mass ratio [(I)/(II)] of the component (I) and the calcium carbonate powder (II) is in the range of 99/1 to 5/95,
(Iii) the calcium carbonate powder (II) has an average particle size of 0.1 to 4 μm,
(Iv) The surface of the calcium carbonate powder (II) is not chemically treated,
Resin composition;
[2] The resin composition according to [1], wherein the component (I) contains a tackifier (B) and/or a plasticizer (C);
[3] The resin composition according to [1] or [2], wherein the (meth)acrylic block copolymer (A) has a weight average molecular weight (Mw) of 50,000 to 300,000.
[4] The resin composition according to any one of [1] to [3], wherein the (meth)acrylic block copolymer (A) has a molecular weight distribution (Mw/Mn) of 1.5 or less;
[5] The resin composition according to any one of [1] to [4], wherein the calcium carbonate powder (II) is a heavy calcium carbonate powder;
[6] An adhesive containing the resin composition according to any one of [1] to [5];
[7] A processed product containing the adhesive according to [6];
Achieved by.

According to the present invention, it is possible to obtain a tacky adhesive having a small shear rate dependency of viscosity, excellent hot melt extrusion coating property, holding power, and less exudation of a plasticizer even when a plasticizer is contained, It is possible to provide a resin composition excellent in economic efficiency. Further, the resin composition of the present invention can be suitably used as an adhesive.

Hereinafter, the present invention will be described in detail. In this specification, methacrylic and acrylic may be collectively referred to as “(meth)acrylic”. In addition, the pressure-sensitive adhesive and the adhesive may be collectively referred to as “adhesive/adhesive”. In addition, a material that has both adhesive and adhesive properties, for example, designed to temporarily fix by adhesive during adhesive work and then to increase the cohesive force by some means to finally change to adhesive and demonstrate practical strength. The applied adhesive material is also included in the "adhesive".

The resin composition of the present invention contains the (meth)acrylic block copolymer (A) as the component (I). Since the resin composition contains the component (I), the resin composition has excellent adhesiveness.
The (meth)acrylic block copolymer (A) contained in the component (I) is usually at least one polymer block (a1) consisting of a methacrylic acid alkyl ester unit and at least one polymer block consisting of an acrylic acid alkyl ester unit. And the polymer block (a2). By including such a (meth)acrylic block copolymer (A) as the component (I), a resin composition having excellent adhesiveness such as heat resistance, weather resistance and holding power (cohesive force) can be obtained. Be done.

Examples of the methacrylic acid alkyl ester that is a constituent unit of the polymer block (a1) include, for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, n-hexyl methacrylate. , Cyclohexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate, isobornyl methacrylate and the like. Among these, methyl methacrylate, ethyl methacrylate, and propyl methacrylate are preferable, and methyl methacrylate is preferable because it is economically easily available and the polymer block (a1) obtained has excellent durability and weather resistance. More preferable.

The alkyl methacrylic acid ester unit, which is a constituent unit of the polymer block (a1), may be composed of one kind alone, or may be composed of two or more kinds. The proportion of methacrylic acid alkyl ester units contained in the polymer block (a1) is preferably 60% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, in the polymer block (a1). Moreover, the polymer block (a1) may be 100% by mass of a methacrylic acid alkyl ester unit.

The polymer block (a1) may contain other monomer units as long as the effects of the present invention are not impaired. Examples of such other monomers include methacrylic acid esters having no functional group other than methacrylic acid alkyl esters such as phenyl methacrylate and benzyl methacrylate; methacrylic acid alkoxy such as methoxyethyl methacrylate and ethoxyethyl methacrylate. Methacrylic acid ester having functional group such as alkyl ester, diethylaminoethyl methacrylate, 2-hydroxyethyl methacrylate, 2-aminoethyl methacrylate, glycidyl methacrylate, tetrahydrofurfuryl methacrylate; acrylic acid alkyl ester described later; acrylic Acrylic acid esters having no functional groups other than acrylic acid alkyl esters such as phenyl acid and benzyl acrylate; alkoxyalkyl alkyl esters such as methoxyethyl acrylate and ethoxyethyl acrylate; diethylaminoethyl acrylate; acrylic acid 2 -Acrylic acid ester having a functional group such as hydroxyethyl, 2-aminoethyl acrylate, glycidyl acrylate, tetrahydrofurfuryl acrylate; (meth)acrylic acid, crotonic acid, maleic acid, maleic anhydride, fumaric acid, Vinyl-based monomers having a carboxyl group such as (meth)acrylamide; vinyl-based monomers having a functional group such as (meth)acrylonitrile, vinyl acetate, vinyl chloride, vinylidene chloride; styrene, α-methylstyrene, p -Aromatic vinyl-based monomers such as methylstyrene and m-methylstyrene; conjugated diene-based monomers such as butadiene and isoprene; olefin-based monomers such as ethylene, propylene, isobutene and octene; ε-caprolactone, valero Examples thereof include lactone monomers such as lactone. When these monomers are used, they are usually used in a small amount, but preferably 40% by mass or less, more preferably 20% by mass based on the total mass of the monomers used for forming the polymer block (a1). % Or less, more preferably 10% by mass or less.

The glass transition temperature of the polymer block (a1) is preferably 25° C. or higher, more preferably 50° C. or higher, even more preferably 60° C. or higher. When the glass transition temperature of the polymer block (a1) is within the above range, when the resin composition of the present invention is used as an adhesive, the cohesive force tends to be excellent. The glass transition temperature is an extrapolation start temperature of a curve obtained by differential scanning calorimetry (DSC).

The (meth)acrylic block copolymer (A) may include two or more polymer blocks (a1). In that case, the polymer blocks (a1) may be the same. May be different.

The weight average molecular weight (Mw) of the polymer block (a1) is not particularly limited, but is preferably in the range of 500 to 50,000, more preferably 500 to 25,000, and more preferably 4,000. It is more preferably in the range of ˜25,000. When the Mw of the polymer block (a1) is smaller than this range, there is a problem that the obtained (meth)acrylic block copolymer (A) has insufficient cohesive force. Further, when the Mw of the polymer block (a1) is larger than this range, the melt viscosity of the (meth)acrylic block copolymer (A) obtained becomes high and the (meth)acrylic block copolymer ( In some cases, the productivity of A) and the handleability of the resulting acrylic hot melt adhesive are poor. In addition, in this specification, Mw means the weight average molecular weight of standard polystyrene conversion measured by gel permeation chromatography (GPC).

Examples of the alkyl acrylate which is a structural unit of the polymer block (a2) include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, t-butyl acrylate, n-hexyl acrylate, Examples thereof include cyclohexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, lauryl acrylate, tridecyl acrylate and stearyl acrylate.

When the main chain carbon number of the alkyl group of the acrylic acid alkyl ester is a short-chain alkyl group having 4 or less (for example, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, t-butyl acrylate) Etc.) tends to improve the fluidity of the (meth)acrylic block copolymer (A). In the case where the alkyl group contained in the acrylic acid alkyl ester is a long-chain alkyl group having a main chain carbon number of 6 or more (for example, as the acrylic acid alkyl ester, n-hexyl acrylate, cyclohexyl acrylate, acrylic acid 2- Ethylhexyl, n-octyl acrylate, lauryl acrylate, tridecyl acrylate, stearyl acrylate, etc.) tends to improve the low temperature properties of the (meth)acrylic block copolymer (A).

The alkyl acrylate unit, which is a constituent unit of the polymer block (a2), may be composed of one kind alone, or may be composed of two or more kinds. The proportion of acrylic acid alkyl ester units contained in the polymer block (a2) is preferably 60% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, in the polymer block (a2). Further, the polymer block (a2) may be 100% by mass of alkyl acrylate unit.

The polymer block (a2) may contain other monomer units as long as the effects of the present invention are not impaired. Examples of the other monomer constituting the unit include, for example, the methacrylic acid alkyl ester and the methacrylic acid ester having no functional group other than the methacrylic acid alkyl ester and the methacrylic acid alkyl ester described in the part of the polymer block (a1), and the functional group. Other than methacrylic acid ester having acrylate and alkyl acrylate ester, acrylic acid ester not having functional group, acrylic acid ester having functional group, vinyl monomer having carboxyl group, vinyl monomer having functional group , Aromatic vinyl-based monomers, conjugated diene-based monomers, olefin-based monomers, lactone-based monomers and the like. When these monomers are used, they are usually used in a small amount, but preferably 40% by mass or less, more preferably 20% by mass, based on the total mass of the monomers used for forming the polymer block (a1). % Or less, more preferably 10% by mass or less.

The glass transition temperature of the polymer block (a2) is preferably −20° C. or lower, more preferably −30° C. or lower.
When the glass transition temperature of the polymer block (a2) is within the above range, a (meth)acrylic block copolymer (A) having excellent flexibility and properties as a tacky adhesive even in a low temperature region can be obtained. Among the above-mentioned acrylic acid esters, propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and acrylic acid are preferred because the glass transition temperature of the polymer block (a2) falls within the above-mentioned preferred range and is easily available. N-octyl acid is preferred. The glass transition temperature is the extrapolation start temperature of the curve obtained by DSC.

The (meth)acrylic block copolymer (A) may include two or more polymer blocks (a2). In that case, the polymer blocks (a2) may be the same. May be different.

Further, the difference in glass transition temperature between the polymer block (a1) and the polymer block (a2) in the (meth)acrylic block copolymer (A) is preferably 70°C or higher, more preferably 100°C or higher. ..

The above-mentioned (meth)acrylic block copolymer (A) has the general formula: when the polymer block (a1) is “α” and the polymer block (a2) is “β”;
(Α-β) _n
(Α-β) _n −α
β-(α-β) _n
(Α-β) _n -Z
(Β-α) _n -Z
(In the formula, n represents an integer of 1 to 30, and Z represents a coupling site (the coupling site after the coupling agent reacts with the polymer terminal to form a chemical bond)). Is preferred. The value of n is preferably 1 to 15, more preferably 1 to 8, and even more preferably 1 to 4. Among the above structures, a linear block copolymer represented by (α-β) _n , (α-β) _n -α, β-(α-β) _n is preferable, and represented by α-β. The diblock copolymer represented by the formula or the triblock copolymer represented by α-β-α is particularly preferable.

In the above (meth)acrylic block copolymer (A), the content of the polymer block (a1) is 5 to 5 from the viewpoint of making the resulting acrylic hot melt adhesive have excellent performance. It is preferably 55% by mass, more preferably 5 to 35% by mass, and further preferably 5 to 25% by mass.

Since the processability of the obtained resin composition tends to be more excellent, the weight average molecular weight (Mw) of the (meth)acrylic block copolymer (A) is 50,000 to 300,000. It is preferably 50,000 to 200,000, more preferably 50,000 to 160,000, still more preferably 50,000 to 120,000. If the Mw of the (meth)acrylic block copolymer (A) is less than 50,000, the cohesive force of the (meth)acrylic block copolymer (A) will be insufficient, and the resulting adhesive will be Performance may be inferior. In addition, a problem may occur such that the (meth)acrylic block copolymer (A) bleeds onto the surface of the adherend. On the other hand, when the Mw of the (meth)acrylic block copolymer (A) exceeds 300,000, the melt viscosity becomes too high, and, for example, the productivity and processability in producing a tacky adhesive from a resin composition. May be inferior to.

In the (meth)acrylic block copolymer (A), the molecular weight distribution (Mw/Mn) is preferably 1.5 or less, more preferably 1.0 to 1.5, and 1.0 ˜1.4 is more preferable, and 1.0 to 1.3 is particularly preferable. Since the Mw/Mn of the (meth)acrylic block copolymer (A) is in the above range, the cohesive force is high when it is used as a tacky adhesive, and at the same time, contamination of the adherend can be suppressed. it can.

The (meth)acrylic block copolymer (A) preferably contains a (meth)acrylic block copolymer in the form of a solid (for example, pellet). By including such a (meth)acrylic block copolymer as the component (I), a resin composition excellent in heat resistance, weather resistance, and viscous adhesiveness such as holding power (cohesive force) can be obtained. The solid (meth)acrylic block copolymer typically has an elastic modulus (G′) at 23° C. of 1×10 ⁴ Pa or more.

Further, the component (I) may include a liquid (meth)acrylic block copolymer in addition to the (meth)acrylic block copolymer having the above solid form. The liquid (meth)acrylic block copolymer typically has an elastic modulus (G′) at 23° C. of less than 1×10 ⁴ Pa.

The method for producing the (meth)acrylic block copolymer (A) is not particularly limited, and the (meth)acrylic block copolymer (A) can be produced by a known method. Generally, as a method of obtaining a block copolymer having a narrow molecular weight distribution, a method of living polymerization of a monomer which is a structural unit is adopted. Examples of such living polymerization methods include a method of living polymerization using an organic rare earth metal complex as a polymerization initiator (see, for example, Patent Document 2), and an alkali metal or alkaline earth compound using an organic alkali metal compound as a polymerization initiator. Living anionic polymerization in the presence of a mineral salt such as a metal salt (see, for example, Patent Document 3), living anionic polymerization in the presence of an organic aluminum compound using an organic alkali metal compound as a polymerization initiator (for example, Patent Document 4), atom transfer radical polymerization method (ATRP) and the like. Moreover, you may use a commercial item as a (meth)acrylic block copolymer (A). Examples of commercially available products include "Clarity (registered trademark) series" manufactured by Kuraray Co., Ltd. and the like.

The content of the (meth)acrylic block copolymer (A) in the component (I) is 30% by mass or more. When the content of the (meth)acrylic block copolymer (A) in the component (I) is 30% by mass or more, a tacky adhesive having excellent holding power, and a plasticizer even when a plasticizer is contained It is possible to obtain a resin composition capable of producing a tacky-adhesive agent with less exudation. The content of the (meth)acrylic block copolymer (A) is 30 to 30 from the viewpoint of excellent holding power, exudation of a plasticizer, and processability during melting represented by extrusion coatability. It is preferably 80% by mass, more preferably 40 to 80% by mass, and further preferably 40 to 60% by mass.

The component (I) preferably further contains at least one selected from a tackifier (B) and/or a plasticizer (C), that is, a tackifier (B) and a plasticizer (C). .. By including such a component (I) in the resin composition, a resin composition having excellent adhesive/bonding performance can be obtained. Further, from the viewpoint of reducing the shear rate dependence of the viscosity of the tacky-adhesive agent obtained from the resin composition of the present invention and making extrusion coatability, holding power and the like excellent, the pressure-sensitive adhesive as component (I) It is a preferred embodiment to include both the imparting agent (B) and the plasticizer (C).

In the resin composition of the present invention, the component (I) containing the tackifier (B) improves the adhesiveness, tackiness and compatibility. Examples of the tackifier (B) include tackifying resins. Examples of the tackifying resin include hydrocarbon resins, terpene resins, rosin resins, hydrogenated products of these resins (hereinafter sometimes referred to as “hydrogenation”), styrene resins, alkylphenol resins, xylene resins, coumarone indene. Resin etc. are mentioned.

In the present invention, the hydrocarbon resin is a raw material composed of a C ₅ fraction, a C ₉ fraction, a purified component of the C ₅ fraction, a purified component of the C ₉ fraction, or a mixture of these fractions or purified components. This is an oligomer obtained. The C ₅ fraction is usually cyclopentadiene, dicyclopentadiene, isoprene, 1,3-pentadiene, 2-methyl-1-butene, 2-methyl-2-butene, 1-pentene, 2-pentene and Cyclopentene and the like are contained, and the C ₉ fraction usually contains styrene, allylbenzene, α-methylstyrene, vinyltoluene, β-methylstyrene, indene and the like. Further, the C ₉ fraction may contain a small amount of C ₈ fraction and C ₁₀ fraction.

The hydrocarbon resins, C ₅ fraction or C ₅ resins the purified components were the raw material (also known as aliphatic hydrocarbon resins), C ₉ fraction or C ₉ resin (alias the purified components were the raw material: Aromatic hydrocarbon resin), a C ₅ -C ₉ copolymer resin (also known as an aliphatic-aromatic copolymer resin) prepared from a mixture of a C ₅ fraction or a purified component thereof and a C ₉ fraction or a purified component thereof as a raw material. Polymerized hydrocarbon resins).

In the present invention, the terpene resin is an oligomer obtained by polymerizing a raw material containing a terpene-based monomer. The terpene generally means a polymer of isoprene (C ₅ H ₈ ) and is classified into monoterpene (C ₁₀ H ₁₆ ), sesquiterpene (C ₁₅ H ₂₄ ), diterpene (C ₂₀ H ₃₂ ), and the like. It The terpene-based monomer is a monomer having these as a basic skeleton, for example, α-pinene, β-pinene, dipentene, limonene, myrcene, aloocimene, ocimene, α-ferrandrain, α-terpinene, γ. -Terpinene, terpinolene, 1,8-cineole, 1,4-cineole, α-terpineneol, β-terpineneol, γ-terpineneol, sabinene, paramenthadiene, and karen. Further, the raw material containing the terpene-based monomer includes other monomers copolymerizable with the terpene-based monomer, for example, coumarone-based monomers such as benzofuran (C ₈ H ₆ O); styrene, α- Vinyl aromatic compounds such as methylstyrene, vinyltoluene, divinyltoluene, 2-phenyl-2-butene; phenol, cresol, xylenol, propylphenol, nonylphenol, hydroquinone, resorcin, methoxyphenol, bromophenol, bisphenol A, bisphenol F, etc. The phenolic monomer and the like may be included.

In the present invention, the rosin-based resin is an amber, amorphous natural resin obtained from pine, and its main component is a mixture of abietic acid and its isomers. The rosin resin also includes those modified by esterification, polymerization or the like by utilizing the reactivity of the abietic acid or its isomer.

As the tackifying resin, a commercially available product may be used, and examples thereof include Quinton 100 series (manufactured by Nippon Zeon Co., Ltd.), Alcon M series, Alcon P series (manufactured by Arakawa Chemical Industry Co., Ltd.), Imarve series (Idemitsu). Hydrocarbon resins such as Kosan Co., Ltd.; terpene resins such as Clearon series, YS Polystar series, YS resin series (all manufactured by Yasuhara Chemical Co., Ltd.), Tamanor 901 (manufactured by Arakawa Chemical Co., Ltd.); Pine Crystal KE- 100, Pine Crystal KE-311, Pine Crystal KE-359, Pine Crystal KE-604, Pine Crystal D-6250, Pencel D125, Pencel D160, Ester gum H series, Ester gum HP series (all manufactured by Arakawa Chemical Industries, Ltd. ), rosin resins such as Foral85 (manufactured by Pinova); styrene resins such as YS resin SX100 (manufactured by Yasuhara Chemical Co., Ltd.), Kristalex F100 (manufactured by Eastman Chemical Japan Co., Ltd.), FTR6100 (manufactured by Mitsui Chemicals Co., Ltd.), Tamanoru 521. (Arakawa Chemical Industry Co., Ltd.) and other alkylphenol resins; Nikanol L (Fudo Co., Ltd.) and other xylene resins; Coumaron V-120S (Nippon Kagaku Co., Ltd.) and other coumarone indene resins are preferably used. it can.

Among the above tackifying resins, hydrocarbon resins, terpene resins, rosin resins, and hydrogenated products thereof, and styrene resins are preferable in terms of exhibiting high adhesive strength and tack, and adhesiveness to a wide variety of adherends. From the viewpoint of the above, a hydrocarbon resin, a terpene resin, a rosin resin, and hydrogenated products thereof are more preferable. These may be used alone or in combination of two or more. When two or more kinds of these tackifier-containing resins are contained, it is desirable in terms of excellent balance of adhesive strength and tack. Further, the softening point of the tackifying resin is preferably 50 to 160° C. from the viewpoint of exhibiting high adhesive strength.

The content of the tackifier (B) in the component (I) is preferably 70% by mass or less, and 5 to 50% by mass, from the viewpoint of excellent balance of adhesiveness, tack, holding power and compatibility. Is more preferable, 8 to 40% by mass is more preferable, and 15 to 40% by mass is still more preferable.

When the component (I) contains the plasticizer (C), a resin composition having excellent hot melt processability can be obtained, and generally, the cost of the resin composition as a whole can be reduced. Examples of the plasticizer (C) include phthalic acid esters such as dibutyl phthalate, di-n-octyl phthalate, bis-2-ethylhexyl phthalate, di-n-decyl phthalate and diisodecyl phthalate, bis-2-ethylhexyl adipate. , Di-n-octyl adipate, adipic acid esters, sebacic acid esters, azelaic acid esters, citric acid esters, and the like, and organic acid esters derived from organic acids having a main chain carbon number of 2 to 10 and the like. Oligomer; Paraffins such as chlorinated paraffins; Glycols such as polypropylene glycol; Epoxy polymer plasticizers such as epoxidized soybean oil and epoxidized linseed oil; Phosphate esters such as trioctyl phosphate and triphenyl phosphate; Bis Sebacic acid esters such as 2-ethylhexyl sebacate, di-n-butyl sebacate, fatty acid esters such as azelaic acid esters such as bis-2-ethylhexyl azelate; phosphite esters such as triphenyl phosphite; Acrylic oligomers such as n-butyl poly(meth)acrylate and 2-ethylhexyl poly(meth)acrylate; polybutene; polyisobutylene; polyisoprene; process oil and the like, and these may be contained alone. Good, or two or more kinds may be contained.

Among these, as the plasticizer (C), acrylic oligomers and organic acid esters derived from an organic acid having 2 to 10 carbon atoms are preferred from the viewpoint of cohesive force, compatibility, and balance of melt viscosity. preferable. As the acrylic oligomer, Alfon UP series (manufactured by Toagosei Co., Ltd.), Micryl series (manufactured by BASF), and as organic acid esters, tributyl acetyl citrate, bis(2-ethylhexyl) phthalate, and bis(2-terephthalate) bis(2-) Ethylhexyl) and the like.

The content of the plasticizer (C) in the component (I) is from 0 to 30 mass from the viewpoint of excellent balance between tack, exudation of the plasticizer, and processability at the time of melting represented by extrusion coatability. %, more preferably 5 to 30% by mass, still more preferably 10 to 30% by mass.

The resin composition of the present invention contains calcium carbonate powder (II). Since the resin composition contains the component (II), a tacky adhesive having excellent holding power can be obtained from the resin composition. Further, even when the resin composition contains a plasticizer, the calcium carbonate powder (II) can suppress the exudation of the plasticizer from the component (I).

The calcium carbonate powder (II) has an average particle size of 0.1 to 4 μm. If the average particle size of the calcium carbonate powder (II) is less than 0.1 μm, the calcium carbonate powder (II) tends to aggregate, and the calcium carbonate powder (II) does not mix uniformly during kneading with the component (I) or melts during extrusion coating. Cohesion occurs during retention in the tank and clogging of the die lip tends to deteriorate coatability. When the average particle size of the calcium carbonate powder (II) exceeds 4 μm, the surface irregularity of the resin layer obtained by extrusion coating becomes remarkable, and thus the adhesive force when bonded to an adherend is likely to vary. .. The average particle size of the calcium carbonate powder (II) is preferably 0.1 to 3 μm from the viewpoints of uniform dispersibility, extrusion coatability represented by cohesiveness, and surface smoothness of a coated product. , 0.1 to 2 μm is more preferable, and 0.5 to 2 μm is still more preferable. The average particle size of the calcium carbonate powder (II) can be obtained from the particle size distribution measured by the laser diffraction/scattering method.

The surface of the calcium carbonate powder (II) is not chemically treated. Here, chemically treating the surface of the calcium carbonate powder (II) means that the surface of the calcium carbonate powder (II) is chemically treated with a chemical substance such as a fatty acid, a fatty acid salt, or a surfactant. It means changing to. When an inorganic powder such as calcium carbonate powder whose surface is chemically treated in this way is included in the composition, it is generally said that the aggregation of the powder can be prevented and the thixotropy of the composition can be controlled. On the other hand, when a composition obtained by mixing such a chemically treated inorganic powder with a resin is used, during high temperature processing such as extrusion discharge, the surface treatment is peeled off due to the shear stress of the resin, resulting in coloring or odor of the composition. It may be a cause of occurrence. In the present invention, by using the calcium carbonate powder (II) that has not been chemically treated together with the component (I), a resin composition having excellent dispersibility with the component (I) can be obtained. From the above, a pressure-sensitive adhesive having excellent holding power can be obtained. Further, even when the resin composition contains a plasticizer, the plasticizer does not exude from the resin composition. Further, the shear dependency of the viscosity is small, and the extrusion coatability is excellent.

The calcium carbonate powder (II) is generally roughly classified into heavy calcium carbonate (natural calcium carbonate) powder and synthetic calcium carbonate powder.
The heavy calcium carbonate powder is obtained by mechanically crushing naturally occurring crude crystal limestone (raw calcium carbonate) and, if necessary, classifying. The mechanical crushing of the crude crystal limestone can be carried out by dry or wet crushing using a crusher such as a roller mill, a high speed rotary mill or a ball mill. The classification can be carried out, for example, by using an air classifier after mechanical grinding when dry grinding is performed.

Examples of the synthetic calcium carbonate powder include light calcium carbonate powder, precipitating (colloidal) calcium carbonate powder, and the like. Synthetic calcium carbonate powder, for example, is made by mixing intimate limestone with anthracite or coke and then calcining to give quick lime (calcium oxide), and hydrating the quick lime to prepare lime milk (calcium hydroxide suspension), It can be produced by blowing carbon dioxide into the obtained lime milk. The particle size of the obtained synthetic calcium carbonate powder can be controlled by controlling the conditions under which carbon dioxide gas is blown into the lime milk.

Among the above calcium carbonate powder (II), heavy calcium carbonate powder is preferable. When heavy calcium carbonate powder is used as the above-mentioned calcium carbonate powder (II), since the adhesive agent obtained from the resin composition is not surface-treated with the calcium carbonate powder, excellent adhesive properties and Extrusion coatability is obtained, and aggregation of calcium carbonate powder does not easily occur.

The mass ratio [(I)/(II)] of the above component (I) and calcium carbonate powder (II) is in the range of 99/1 to 5/95. When (I)/(II) exceeds 99/1, the adhesive force obtained from the resin composition is insufficient, and when the resin composition contains a plasticizer, stains of the plasticizer In some cases, it can be seen. If (I)/(II) is less than 5/95, the extrudability of the adhesive composition obtained from the resin composition will be insufficient. The mass ratio (I)/(II) is preferably 99/1 to 10/90, and is preferably 99/1, because the holding power, the exudation of the plasticizer, and the extrusion coatability are all excellent. More preferably, it is -40/60.

The resin composition of the present invention is another polymer within a range that does not impair the effects of the present invention; a softening agent, a heat stabilizer, a light stabilizer, an antistatic agent, a flame retardant, a foaming agent, a coloring agent, a dyeing agent, Additives such as a refractive index adjusting agent, a filler other than the above calcium carbonate powder (II), a curing agent, and an anti-sticking agent may be contained. These other polymers and additives may be contained alone or in combination of two or more.

Examples of the other polymer include acrylic resins such as polymethylmethacrylate and (meth)acrylic acid ester copolymer; polyethylene, ethylene-vinyl acetate copolymer, polypropylene, polybutene-1, poly-4-. Olefin resins such as methylpentene-1, polynorbornene; ethylene ionomers; polystyrene, styrene-maleic anhydride copolymer, high impact polystyrene, AS resin, ABS resin, AES resin, AAS resin, ACS resin, MBS resin, etc. Styrene resin; styrene-methyl methacrylate copolymer; polyester resin such as polyethylene terephthalate, polybutylene terephthalate, polylactic acid; polyamide such as nylon 6, nylon 66, polyamide elastomer; polycarbonate; polyvinyl chloride; polyvinylidene chloride; Polyvinyl alcohol; ethylene-vinyl alcohol copolymer; polyacetal; polyvinylidene fluoride; polyurethane; modified polyphenylene ether; polyphenylene sulfide; silicone rubber modified resin; acrylic rubber; silicone rubber; styrene thermoplastics such as SEPS, SEBS, SIS, etc. Elastomers: olefin rubbers such as IR, EPR, EPDM and the like can be mentioned. Among these, from the viewpoint of compatibility with the (meth)acrylic block copolymer (A) contained in the resin composition, an acrylic resin, an ethylene-vinyl acetate copolymer, an AS resin, a polylactic acid, and a polyfluoride. Vinylidene chloride and styrenic thermoplastic elastomers are preferred.

Examples of the filler include inorganic fibers such as glass fiber and carbon fiber, and organic fibers; inorganic fillers other than calcium carbonate such as talc, carbon black, titanium oxide, silica, clay, barium sulfate, and magnesium carbonate. Be done. When the inorganic fiber and the organic fiber are contained, durability is imparted to the obtained resin composition. When the inorganic filler is contained, heat resistance and weather resistance are given to the obtained resin composition.

When the resin composition of the present invention contains a curing agent, it can be suitably used as a curable pressure-sensitive adhesive. Examples of the curing agent include a photo-curing agent such as a UV curing agent and a thermal curing agent. Examples thereof include benzoins, benzoin ethers, benzophenones, anthraquinones, benzyls, acetophenones, and diacetyls. .. Specifically, benzoin, α-methylolbenzoin, α-t-butylbenzoin, benzoin methyl ether, benzoin ethyl ether, benzoin-n-propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, α-methylolbenzoin methyl ether, α -Methoxybenzoin methyl ether, benzoin phenyl ether, benzophenone, 9,10-anthraquinone, 2-ethyl-9,10-anthraquinone, benzyl, 2,2-dimethoxy-1,2-diphenylethan-1-one (2,2 -Dimethoxy-2-phenylacetophenone), diacetyl and the like. The curing agent may be contained alone or in combination of two or more.

From the viewpoint of enhancing the effect of the curing agent, for example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-halogenated acrylic acid, crotonic acid, cinnamic acid, sorbic acid, maleic acid, itaconic acid, and acrylic acid ester. , Esters such as methacrylic acid ester, crotonic acid ester, maleic acid ester; acrylamide; methacrylamide; acrylamide derivatives such as N-methylolacrylamide, N-hydroxyethylacrylamide, N,N-(dihydroxyethyl)acrylamide; N-methylolmethacryl Methacrylamide derivatives such as amides, N-hydroxyethyl methacrylamide, N,N-(dihydroxyethyl)methacrylamide; vinyl esters; vinyl ethers; mono-N-vinyl derivatives; monomers such as styrene derivatives; The resin composition of the present invention may further contain an oligomer or the like contained as a constituent component. From the viewpoint of enhancing durability, preferred are esters such as acrylic acid esters, methacrylic acid esters, crotonic acid esters, maleic acid esters; vinyl ethers; styrene derivatives; and oligomers containing the above monomers as constituent components. In addition to these monomers, a cross-linking agent composed of a bifunctional or higher functional monomer or oligomer may be further contained.

When the resin composition of the present invention contains an anti-sticking agent, improvement in handleability can be expected. Examples of the anti-sticking agent include fatty acids such as stearic acid and palmitic acid; fatty acid metal salts such as calcium stearate, zinc stearate, magnesium stearate, potassium palmitate and sodium palmitate; polyethylene wax, polypropylene wax, montanic acid. Waxes such as waxes; low molecular weight polyolefins such as low molecular weight polyethylene and low molecular weight polypropylene; acrylic resin powders; polyorganosiloxanes such as dimethylpolysiloxane; octadecylamine, alkyl phosphates, fatty acid esters, ethylenebisstearylamide, etc. Examples thereof include amide resin powder, fluororesin powder such as tetrafluoroethylene resin, molybdenum disulfide powder, silicone resin powder, silicone rubber powder and silica.

The method for producing the resin composition of the present invention is not particularly limited, and for example, each component is usually used at a temperature of 100 to 250° C. using a known mixing or kneading device such as a kneader ruder, an extruder, a mixing roll, or a Banbury mixer. It can be produced by mixing at a temperature within the range. Further, it may be produced by dissolving each component in an organic solvent and mixing them, and then distilling off the organic solvent. The obtained resin composition can be used as a tacky adhesive, for example, it may be melted by heating to be used as a hot melt tacky adhesive, or it may be dissolved in a solvent as a solution type tacky adhesive. May be used. Examples of the solvent include toluene, ethyl acetate, ethylbenzene, methylene chloride, chloroform, tetrahydrofuran, methyl ethyl ketone, dimethyl sulfoxide, toluene-ethanol mixed solvent and the like. Of these, toluene, ethylbenzene, ethyl acetate and methyl ethyl ketone are preferable.

When the resin composition of the present invention is used by heating and melting, it is preferable that the melt viscosity is low from the viewpoint of processability and handleability.
The resin composition of the present invention is in the form of a tacky-adhesive layer made of the resin composition, a laminate (for example, a laminated film or a laminated sheet) including the tacky-adhesive layer, and a process including an adhesive. It is preferably used as a product.

When the resin composition of the present invention is used after being heated and melted to form the adhesive/adhesive layer, for example, a hot melt coating method, a T die method, an inflation method, a calender molding method, a lamination method or the like is used to form a sheet. It can be formed into a shape such as a shape or a film. When the resin composition of the present invention is used by dissolving it in a solvent, for example, a heat-resistant material such as polyethylene terephthalate or a flat plate or roll such as a steel belt is used as a support, and on these, a bar coater, a roll coater, Using a die coater, a comma coater or the like, a solution in which a composition containing the (meth)acrylic block copolymer (A) or the (meth)acrylic block copolymer (A) is dissolved in a solvent is applied, The adhesive layer can be formed using a method of removing the solvent by drying (solution casting method).

The method of removing the solvent by drying is not particularly limited, and a conventionally known method can be used, but it is preferable to perform the drying in a plurality of stages. When the drying is performed in multiple stages, the first-stage drying is performed at a relatively low temperature in order to suppress foaming due to the rapid volatilization of the solvent, and the second-stage and subsequent drying is sufficiently performed. More preferable is a method of performing drying at a high temperature in order to remove the solvent.

The concentration of the (meth)acrylic block copolymer (A) or the composition containing the (meth)acrylic block copolymer (A) in the solution is (meth)acrylic block copolymer (A) or Although it is appropriately determined in consideration of the solubility of the composition containing the (meth)acrylic block copolymer (A) in a solvent, the viscosity of the resulting solution, and the like, a preferable lower limit value is 5% by mass, and a preferable upper limit value is 70%. It is% by mass.

The above laminate can be obtained by laminating an adhesive layer made of the resin composition of the present invention and various base materials such as paper, cellophane, plastic materials, cloth, wood and metal. The base material layer made of a transparent material is suitable because the resin composition of the present invention is excellent in transparency and weather resistance, and thus a transparent laminate can be obtained. As the base material layer made of a transparent material, polyethylene terephthalate, triacetyl cellulose, polyvinyl alcohol, cycloolefin resin, styrene-methyl methacrylate copolymer, polypropylene, polyethylene, polyvinyl chloride, ethylene-vinyl acetate copolymer Examples thereof include a copolymer of a polymer such as polycarbonate, polymethylmethacrylate, polyethylene or polypropylene and various monomers, a mixture of two or more kinds of these polymers, and a base layer made of glass or the like. It is not limited.

As the constitution of the above-mentioned laminate, for example, a two-layer constitution of an adhesive/adhesive layer made of the resin composition of the present invention and a base material layer, an adhesive/adhesive layer made of two base material layers and the resin composition of the present invention. (Base layer/adhesive/adhesive layer/base layer), two different adhesive/adhesive layers (a) and (b) comprising the base layer and the resin composition of the present invention. And a base layer (base layer/adhesive/adhesive layer (a)/adhesive/adhesive layer (b)/base layer), and an adhesive layer comprising the base layer and the resin composition of the present invention. A four-layer structure (base layer/adhesive layer (a)/adhesive layer (c)/substrate) comprising an adhesive layer (a), an adhesive layer (c) made of another material, and a substrate layer. Layer), three base layers and two tacky/adhesive layers made of the resin composition of the present invention (five base layers/tacky/adhesive layer/base material layer/tacky/adhesive layer/base material layer). ) And the like, but the invention is not limited thereto.

The thickness ratio of the above-mentioned laminate is not particularly limited, but from the viewpoint of the tackiness/adhesiveness, durability, and handleability of the tacky/adhesive product to be obtained, base material layer/stickness/adhesive layer=1/1,000 to 1,000 It is preferably in the range of /1, more preferably in the range of 1/200 to 200/1.

When the above-mentioned laminate is manufactured, the tacky-adhesive layer and the base material layer may be respectively formed and then laminated by a lamination method or the like, or the tacky-adhesive layer may be directly formed on the base material layer. Good. Alternatively, the layer structure may be formed at once by co-extruding the adhesive layer and the base material layer, and the laminate may be manufactured as, for example, a co-extruded film or a co-extruded sheet.

In the laminate of the present invention, the surface of the base material layer may be subjected to surface treatment such as corona discharge treatment or plasma discharge treatment in advance in order to enhance the adhesion between the base material layer and the adhesive layer. Further, an anchor layer may be formed on at least one surface of the adhesive/adhesive layer and the base material layer by using an adhesive resin or the like.

Examples of the resin used for the anchor layer include ethylene-vinyl acetate copolymers, ionomers, block copolymers (for example, styrene-based triblock copolymers such as SIS and SBS, and diblock copolymers), Examples thereof include ethylene-acrylic acid copolymers and ethylene-methacrylic acid copolymers. The anchor layer may be a single layer or two or more layers.

In the case of forming the anchor layer, the method is not particularly limited, and for example, a method of forming an anchor layer by applying a solution containing the resin to the base material layer, a composition containing the resin or the like to be the anchor layer Examples include a method of heating and melting and forming an anchor layer on the surface of the base material layer using a T-die or the like.

When the anchor layer is formed, the resin to be the anchor layer and the resin composition of the present invention may be coextruded to integrally laminate the anchor layer and the adhesive layer on the surface of the base layer. A resin serving as an anchor layer and a resin composition may be sequentially laminated on the layer surface, and when the base material layer is a plastic material, a plastic material serving as a base material layer, a resin serving as an anchor layer, and The resin composition may be coextruded at the same time.

The pressure-sensitive adhesive comprising the resin composition of the present invention can be used for various purposes. The tacky-adhesive layer comprising the resin composition can be used alone as a tacky-adhesive sheet, and a laminate containing the tacky-adhesive layer can be applied to various applications. For example, protection such as surface protection, masking, bundling, packaging, office work, label, decoration/display, bonding, dicing tape, sealing, anticorrosion/waterproofing, medical/hygiene, glass Adhesive adhesive for scattering prevention, electrical insulation, electronic device holding and fixing, semiconductor manufacturing, optical display film, adhesive-type optical film, electromagnetic wave shielding, or encapsulating material for electric and electronic parts , Adhesive tape, film or sheet, and the like.

In addition, the processed product containing the tacky-adhesive agent obtained from the resin composition of the present invention usually includes a substrate made of paper, cloth, or various plastics and a tacky-adhesive layer made of the resin composition. Examples of the processed product include adhesive tape for packaging or office work, masking tape for curing or painting, stainless steel plate, surface protection tape for preventing scratches on resin plates, adhesive tape for electrical insulation, Adhesive tapes for electric and electronic devices, adhesive or adhesive tapes for identification or decoration such as marking films, adhesive plasters, medical adhesive products containing transdermal absorbents, labels, adhesive sheet for sealing, construction Tape for building or building materials.

Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the present invention is not limited to these Examples.
In the following synthesis examples, chemicals dried and purified by a conventional method were used.
The molecular weight, molecular weight distribution, composition, and polymerization conversion rate of each polymer synthesized in the following synthesis examples were measured by the following methods.

(1) Number average molecular weight (Mn), weight average molecular weight (Mw), molecular weight distribution (Mw/Mn)
It was determined as a standard polystyrene conversion value by gel permeation chromatography (GPC) under the following conditions.
Device: Tosoh Corporation Gel Permeation Chromatograph (HLC-8020)
Column: Tosoh Corporation "TSKgel GMHXL, G4000HXL" and "G5000HXL" are connected in series Eluent: Tetrahydrofuran Elution flow rate: 1.0 ml/min Column temperature: 40°C
Detection method: Differential refractive index (RI)
Calibration curve: Created using standard polystyrene

(2) Content of each copolymerization component in the acrylic block copolymer
^It was determined by ¹ H-NMR spectroscopy.
Apparatus: JEOL Ltd. nuclear magnetic resonance apparatus (JNM-LA400)
Solvent: Deuterated chloroform
^{In the 1} H-NMR spectrum, signals near 3.6 ppm and 4.0 ppm were obtained from the ester group (—O—CH ₃ ) of the methyl methacrylate unit and the ester group (—O—CH) of the n-butyl acrylate unit, respectively. It is attributed to _{2 -CH 2 -CH 2 -CH 3)} , was determined the content of the copolymerization component by the ratio of the integrated value.

(3) Polymerization conversion rate Obtained by gas chromatography (GC).
Equipment: Shimadzu Corporation Gas Chromatograph GC-14A
Column: GL Sciences Inc. Product made by "INERT CAP 1" (df=0.4 μm, 0.25 mm ID×60 m)
Analysis conditions: injection 300°C, detector 300°C, 60°C (hold for 0 minutes) → temperature increase at 5°C/minute → 100°C (hold for 0 minutes) → temperature increase at 15°C/minute → 300°C (hold for 2 minutes)

<<Synthesis Example 1>> [Synthesis of acrylic triblock copolymer (A-1)]
(1) After replacing the inside of a three-necked flask having a capacity of 2 L with nitrogen, 1069 g of toluene and 41.7 g of 1,2-dimethoxyethane were added with stirring at room temperature (25° C.; the same applies below), and then isobutyl was added. 33.0 g of a toluene solution containing 16.6 mmol of bis(2,6-di-t-butyl-4-methylphenoxy)aluminum was added, and cyclohexane and n-hexane containing 1.84 mmol of sec-butyllithium were mixed. 1.08 g of solution was added.
(2) Subsequently, 14.7 g of methyl methacrylate was added thereto. The reaction mixture initially turned yellow, but became colorless after stirring for 60 minutes at room temperature. At this time, the polymerization conversion rate of methyl methacrylate was 99.9% or more.
(3) Next, the reaction mixture was cooled to -30°C, 242 g of n-butyl acrylate was added dropwise over 2 hours, and after completion of the addition, the mixture was stirred at -30°C for 5 minutes. The polymerization conversion rate of n-butyl acrylate at this time was 99.9% or more.
(4) Further, 19.2 g of methyl methacrylate was added thereto, and after stirring overnight at room temperature, 9.57 g of methanol was added to stop the polymerization reaction. At this time, the polymerization conversion rate of methyl methacrylate was 99.9% or more.
(5) The obtained reaction liquid was poured into 15 kg of methanol to deposit a white precipitate. A white precipitate is collected by filtration and dried to obtain a block copolymer composed of poly(methyl methacrylate) (PMMA)-poly(n-butyl acrylate) (PnBA)-PMMA (hereinafter, referred to as "acrylic triblock copolymer"). 260 g of a polymer (A-1)" is obtained.
(6) As a result of ¹ H-NMR measurement and GPC measurement on the acrylic triblock copolymer (A-1), it was confirmed that the acrylic triblock copolymer was a triblock copolymer, and the weight average molecular weight (Mw) was 194,200, The number average molecular weight (Mn) was 173,900, and the molecular weight distribution (Mw/Mn) was 1.12. Further, the content of each polymer block was 12.1% by mass for the methyl methacrylate polymer block and 87.9% by mass for the n-butyl acrylate polymer block. Further, Table 1 shows the glass transition temperature of each polymer block of the acrylic triblock copolymer (A-1) obtained above.

<<Synthesis Example 2>> [Synthesis of Acrylic Triblock Copolymer (A-2)]
(1) After replacing the inside of a three-necked flask having a capacity of 2 L with nitrogen, 1048 g of toluene and 52.4 g of 1,2-dimethoxyethane were added with stirring at room temperature, and then isobutylbis(2,6-diene) was added. 50.0 g of a toluene solution containing 10.9 mmol of -t-butyl-4-methylphenoxy)aluminum was added, and 4.01 g of a mixed solution of cyclohexane and n-hexane containing 2.31 mmol of sec-butyllithium was added. ..
(2) Subsequently, 18.0 g of methyl methacrylate was added thereto. The reaction mixture initially turned yellow, but became colorless after stirring for 60 minutes at room temperature. At this time, the polymerization conversion rate of methyl methacrylate was 99.9% or more.
(3) Next, the reaction mixture was cooled to −30° C., 221.2 g of n-butyl acrylate was added dropwise over 2 hours, and after completion of the addition, the mixture was stirred at −30° C. for 5 minutes. The polymerization conversion rate of n-butyl acrylate at this time was 99.9% or more.
(4) Further, 24.5 g of methyl methacrylate was added to this, and after stirring overnight at room temperature, 13.0 g of methanol was added to stop the polymerization reaction. At this time, the polymerization conversion rate of methyl methacrylate was 99.9% or more.
(5) The obtained reaction liquid was poured into 15 kg of methanol to deposit a white precipitate. A white precipitate was collected by filtration and dried to obtain 262 g of a block copolymer composed of PMMA-PnBA-PMMA (hereinafter, referred to as "acrylic triblock copolymer (A-2)"). It was
(6) As a result of ¹ H-NMR measurement and GPC measurement of the acrylic triblock copolymer (A-2), it is surely a triblock copolymer, and the weight average molecular weight (Mw) is 155,000, The number average molecular weight (Mn) was 135,600 and the molecular weight distribution (Mw/Mn) was 1.14. Furthermore, the content of each polymer block was 16.1% by mass for the methyl methacrylate polymer block and 83.9% by mass for the n-butyl acrylate polymer block. In addition, Table 1 shows the glass transition temperature of each polymer block of the acrylic triblock copolymer (A-2) obtained above.

<<Synthesis Example 3>> [Synthesis of Acrylic Diblock Copolymer (A-3)]
(1) After replacing the inside of a three-necked flask having a volume of 2 L with nitrogen, 870 g of toluene and 44.0 g of 1,2-dimethoxyethane were added with stirring at room temperature, and then isobutylbis(2,6-diene) was added. 30.9 g of a toluene solution containing 20.7 mmol of -t-butyl-4-methylphenoxy)aluminum was added, and 2.99 g of a mixed solution of cyclohexane and n-hexane containing 5.17 mmol of sec-butyllithium was added. ..
(2) Subsequently, 21.7 g of methyl methacrylate was added thereto. The reaction mixture initially turned yellow, but became colorless after stirring for 60 minutes at room temperature. At this time, the polymerization conversion rate of methyl methacrylate was 99.9% or more.
(3) Next, the reaction mixture was cooled to −30° C., 288.4 g of n-butyl acrylate was added dropwise over 2 hours, and after completion of dropping, the mixture was stirred at −30° C. for 5 minutes. The polymerization conversion rate of n-butyl acrylate at this time was 99.9% or more.
(4) The obtained reaction liquid was poured into 15 kg of methanol to deposit an oily precipitate. The oily precipitate was collected by filtration and dried to obtain 310 g of a block copolymer made of PMMA-PnBA (hereinafter, referred to as “acrylic diblock copolymer (A-3)”).
(5) As a result of ¹ H-NMR measurement and GPC measurement of the acrylic diblock copolymer (A-3), it is surely a diblock copolymer, and the weight average molecular weight (Mw) is 67,000, The number average molecular weight (Mn) was 55,400, and the molecular weight distribution (Mw/Mn) was 1.21. Further, the content of each polymer block was such that the methyl methacrylate polymer block was 6.9% by mass and the n-butyl acrylate polymer block was 93.1% by mass. Further, GPC measurement of the reaction mixture sampled when the polymerization of methyl methacrylate was completed revealed that the weight average molecular weight (Mw) of the methyl methacrylate polymer block was 4,400 and the number average molecular weight (Mn) was It was 4,200 and the molecular weight distribution (Mw/Mn) was 1.05. In addition, Table 1 shows the glass transition temperature of each polymer block of the acrylic diblock copolymer (A-3) obtained above.

The properties of the acrylic triblock copolymers or acrylic diblock copolymers (A-1) to (A-3) synthesized in Synthesis Examples 1 to 3 above are summarized in Table 1 below.

The resin compositions and pressure-sensitive adhesive films obtained in Examples and Comparative Examples described below were evaluated by the following test methods.

[Dependence of viscosity on shear rate]
12 g of the resin composition produced in each of the examples or comparative examples described later was melted under the condition of 140° C. by a Brookfield rotational viscometer, and No. Using a 29-inch spindle, the rotation torque was stable in the range of possible rotation speeds of 0.3 times/minute to 100 times/minute for low-speed rotation side (low share) and high-speed rotation side (high share). Each viscosity was measured.

[Hot melt extrusion coating property]
The resin compositions prepared in Examples or Comparative Examples described later were extrusion coated under the conditions of 140° C. using a hot melt applicator manufactured by Suntool Co., Ltd. (coating width 180 mm). When the pressure-sensitive adhesive composition was spread over both ends of the die and was uniformly discharged in the width direction, it was judged as “◯”, and when the discharge amount from both ends was small, it was judged as “x”.

[Aggregation of calcium carbonate powder]
The resin compositions prepared in Examples or Comparative Examples described later were extrusion coated under the conditions of 140° C. using a hot melt applicator manufactured by Suntool Co., Ltd. (coating width 180 mm). After 100 cycles of continuous coating aiming at a coating thickness of 20 μm, the coating thickness is stable in the range of 18 μm to 22 μm, and when the coating product is observed and aggregation of calcium carbonate powder is not observed, “none”, When the coating thickness deviated or agglomeration was observed, it was determined to be “present”.

[Plasticizer seepage test]
The pressure-sensitive adhesive films produced in Examples or Comparative Examples described below were cut into 25 mm×100 mm size test pieces, and the test pieces were recycled paper (C2r manufactured by Fuji Xerox Co., Ltd., weighing 70 g/m 2 ). ^It was attached to ² ) and an environmental test was performed under the condition of a temperature of 60°C. As for the test result, the site where the adhesive film was attached was observed from the back side to determine whether or not the plasticizer oozes out.

[Holding power test (creep test)]
The pressure-sensitive adhesive films produced in Examples or Comparative Examples described later were cut into a size of 25 mm×25 mm to prepare a test piece, the test piece was attached to an SUS plate as an adherend, and a weight of 500 g was applied to the test piece. It was attached and carried out under the condition of a temperature of 60° C. according to JIS Z 0237. The test results were evaluated as “◯” when the drop time was 200 minutes or more, “Δ” when 10 minutes or more and less than 200 minutes, and “x” when it was less than 10 minutes. This test is a test for investigating the durability of the pressure-sensitive adhesive under heating, and the longer the time until the test piece falls off, the more excellent the pressure-sensitive adhesive retains.

The components used in Examples and Comparative Examples described below are as follows.
(Meth)acrylic block copolymer (A)
(Meth)acrylic block copolymers (A-1) to (A-3) produced in Synthesis Examples 1 to 3.
Tackifier (B)
(B-1) Styrene resin "YS resin SX100" (Yasuhara Chemical Co., Ltd., softening point 95-105°C)
(B-2) Hydrogenated rosin ester “Foral 85” (manufactured by Pinova, softening point 80 to 88° C.)
Plasticizer (C)
(C-1) Acrylic acid polymer "Alfon UP-1171" (manufactured by Toagosei Co., Ltd.)
(C-2) Acetyl citrate tributyl "ATBC" (Asahi Kasei Finechem Co., Ltd.)
Calcium carbonate powder (II)
(II-1) Heavy calcium carbonate powder “Softon 2200” (manufactured by Shiraishi Calcium Co., Ltd., average particle size 1.0 μm)
(II-2) Synthetic calcium carbonate powder “Brilliant-1500” (manufactured by Shiraishi Calcium Co., Ltd., average particle size 1.0 μm)
(II-3) Surface Treatment Synthetic Calcium Carbonate Powder “Shiragika CC” (manufactured by Shiraishi Calcium Co., average particle diameter 0.05 μm, fatty acid surface treatment)
(II-4) Surface Treatment Synthetic Calcium Carbonate Powder “Vigot 15” (Shiraishi Calcium Co., Ltd., average particle size 0.15 μm, fatty acid surface treatment)
(II-5) Heavy calcium carbonate powder “BF-200” (manufactured by Shiraishi Calcium Co., average particle size 5.0 μm)

<<Example 1>>
[Preparation of Acrylic Hot Melt Adhesive (D-1)]
(1) 100 parts by mass of acrylic triblock copolymer (A-1), 75 parts by mass of SX100 (manufactured by Yasuhara Chemical Co., Ltd., styrene resin, softening point 100° C.), Alfon UP-1171 (manufactured by Toagosei Co., Ltd., acryl) Acid-based polymer) 30 parts by mass, ATBC (manufactured by Asahi Kasei Finechem Co., Ltd.) 30 parts by mass, and Softon 2200 (manufactured by Shiraishi Calcium Co., Ltd., calcium carbonate powder) 60 parts by mass at 150° C. using a 3 L batch kneader. A resin composition was prepared by kneading until uniform, and an acrylic hot melt adhesive (D-1) made of the resin composition was obtained.
(2) 200 g of the acrylic hot melt adhesive (D-1) was filled in a melter tank attached to a hot melt applicator manufactured by Suntool Co., Ltd. and heated to 140°C. An adhesive film having a width of 180 mm×a length of 240 mm and a coating thickness of 20 μm was produced at a discharge pressure of 0.5 MPa/cm ² and a coating speed of 50 mm/sec.

<<Examples 2-5, Comparative Examples 1-7>>
Acrylic hot-melt adhesives (D-2) to (D-12), and a coating thickness of 20 μm, as in Example 1, except that the composition of the resin composition was changed to that shown in Table 2. An adhesive film was produced. The results are shown in Table 2.

As shown in Table 2, the resin composition of the present invention has a small shear rate dependence of viscosity, is excellent in hot melt extrusion coatability and holding power, and does not exude the plasticizer even when it contains a plasticizer. It turns out that an adhesive can be obtained.

Claims (8)

A resin composition comprising a component (I) containing a (meth)acrylic block copolymer (A) and a calcium carbonate powder (II),
The component (I) contains a tackifying resin having a softening point of 50 to 160° C.,
(I) The content of the (meth)acrylic block copolymer (A) in the component (I) is 40 % by mass or more,
(Ii) Mass ratio of component (I) and calcium carbonate powder (II) [(I)/(II)]=99/
In the range of 1-5/95,
(Iii) the calcium carbonate powder (II) has an average particle size of 0.1 to 4 μm,
(Iv) The surface of the calcium carbonate powder (II) is not chemically treated,
Resin composition. The resin composition according to claim 1, wherein the content of the (meth)acrylic block copolymer (A) in the component (I) is 40 to 80% by mass. Wherein component (I) contains a soluble plasticizer (C), according to claim 1 or resin composition according to 2. The weight average molecular weight (Mw) of the (meth)acrylic block copolymer (A) is 50,000.
The resin composition according to any one of claims 1 to 3, wherein the resin composition is ˜300,000. (Meth) acrylic block copolymer (A) molecular weight distribution (Mw / Mn) of 1.5 or less, the resin composition according to any one of claims 1-4. Calcium carbonate powder (II) is a heavy calcium carbonate powder, a resin composition according to any one of claims 1-5. Adhesive comprising a resin composition according to any one of claims 1-6. A processed product containing the adhesive according to claim 7 .