Abstract: Improved grafted propylene copolymer compositions and adhesive blends containing same are provided. The grafts are obtained by reacting propylene-ethylene impact copolymers having specified rubber contents and molecular weight distributions with ethylenically unsaturated acids or acid derivatives, such as maleic anhydride.

Abstract: An insulating material comprising a cycloolefin polymer, specifically, an interlayer insulating material for a high-density assembly board having interlayer-connecting via holes at most 200 &mgr;m in diameter, comprising a cycloolefin polymer containing at least 50 mol % of a repeating unit derived from a cycloolefin monomer; a dry film formed from a curable resin composition comprising a polymer having a number average molecular weight within a range of 1,000 to 1,000,000 as measured by gel permeation chromatography, and a hardener; and a resin-attached metal foil obtained by forming a film of a cycloolefin polymer on one side of a metal foil. Laminates, multi-layer laminates and build-up multi-layer laminates making use of these materials, and production processes thereof.

Abstract: An anisotropically electroconductive film, which has a high reliability in its capacity for conducting electricity and also a good adhesion under such an adhesive condition that the film is heated at a temperature of 130° C. or less for a short period of time, has a layer of an adhesive within which electroconductive particles are distributed. The adhesive is composed of a thermosetting resin composition including a base resin, a reactive compound, an organic peroxide and a reaction accelerating compound, and also the electroconductive particles incorporated into the thermosetting resin composition. The base resin is a polyacetalized resin which is obtained by acetalizing a polyvinyl alcohol. The reactive compound is at least one selected from a group consisting of acryloxy group-bearing compounds, methacryloxy group-bearing compounds and epoxy group-bearing compounds. The reaction accelerating compound is a compound which has a radically reactive group and alkali-reactive group as its end groups.

Abstract: Emulsion polymers useful in the preparation of coatings and adhesives, including PSA tapes, labels, and other constructions, are provided. The polymers are characterized by high solids content and low viscosity. A method of making the polymers is also provided. A plurality of acrylic monomers are copolymerized in the presence of a plurality of surfactants, using a split feed, and the resulting emulsion polymers have a bimodal or higher particle-size distribution.

Abstract: An object of the present invention is to provide a water adsorbing/desorbing organic polymer material having excellent water adsorbing/desorbing performance and which is inexpensive and readily disposable by incineration or the like. In order to attain this object, water adsorbing/desorbing organic polymer materials of the present invention are characterized by having a polymer side chain containing a hydrophilic group on the backbone of an organic polymer base.

Abstract: Aqueous water repellent coating compositions comprising admixtures of (i) water-based water repellent compositions and (ii) water-reducible film-forming polymers are disclosed.

Abstract: Disclosed are a composite material containing (A) a modified polyolefin resin graft-modified with an unsaturated carboxylic acid and/or its derivative and (B) a filler, wherein a content of the component (B) is from 1 to 80 parts by weight based on 100 parts by weight of a combined content of the components (A) and (B), a graft amount of the unsaturated carboxylic acid and/or its derivative in the component (A) is 0.3% by weight or more, and the component (A) has a melt flow rate as measured at 230° C. and a load of 21.2 N of 400 g/10 min or less and a composite material further containing (C) a polyolefin resin.

Abstract: Cross-linked block copolymers are disclosed which have drug retention properties, comprising hard and soft segments, with cross-linking between the soft segments. The block copolymers can be based upon (meth)acrylic monomers, and some possess adhesive properties.

Abstract: The present invention relates to a resin solution composition for paints or adhesives which comprises an acid-modified butene-1/&agr;-olefin copolymer obtained by modifying a butene-1/&agr;-olefin copolymer with an unsaturated carboxylic acid or an acid anhydride thereof. The butene-1/&agr;-olefin copolymer comprises, as polymerizable components, 65 to 85 mol % butene-1 component and 15 to 35 mol % &agr;-olefin component having 2 to 8 carbon atoms other than butene-1 component. The acid-modified butene-1/&agr;-olefin copolymer comprises the unsaturated carboxylic acid or the anhydride thereof in a proportion of 0.5 to 5% by weight. In this resin solution composition, the acid-modified butene-1/&agr;-olefin copolymer is dissolved in an organic solvent, in a solid content of 10 to 30% by weight.

Abstract: A graft polymer according to the invention contains a backbone of one or more substantially random interpolymers, comprising: (1) polymer units derived from: (a) at least one vinyl or vinylidene aromatic monomer, or (b) at least one hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer, or (c) a combination of at least one aromatic vinyl or vinylidene monomer and at least one hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer, and (2) polymer units derived from at least one of ethylene and/or a C3-20 &agr;-olefin; and (3) optionally polymer units derived from one or more of ethylenically unsaturated polymerizable monomers other than those derived from (1) and (2); said backbone being grafted with one or more olefinically unsaturated organic monomer(s). In a preferred embodiment such graft polymers were prepared using a reactive extrusion process.

Abstract: The present invention has for its object to provide a polymer available upon coupling of polymers of radical-polymerizable olefin monomer or monomers and a process for producing said polymer. The present invention is concerned with a method for effecting polymer-polymer coupling in the living radical polymerization of a radical-polymerizable olefin monomer which comprises adding a compound having at least two sparingly radical-polymerizable alkenyl groups during or after polymerization.

Abstract: A method of preparing a curable coating and a method of curing the curable coating are disclosed. The curable composition from which the curable coating is prepared may be applied to the surface of a substrate in neat form or in aqueous medium to produce the coating. Curing of the curable coating may be accomplished by chemical generation of free radicals, by electrochemical generation of free radicals, by electron beam, by photochemical generation of free radicals, or by other electromagnetic irradiation.

Abstract: A water-borne paint composition including an opacifying pigment, a core-shell polymer with acid functionality, and a polymer polymerized from a group of monomers including a macromonomer having a hydrophobic portion and an alkoxylated portion. The core-shell polymer includes a shell and a core, wherein the weight of the shell is less than 10% of the weight of the core.

Abstract: A method of forming, by polymerization in an aqueous dispersion at pressures in excess of one atmosphere, a plurality of porous particles having at least one polymeric phase and, additionally, having a pore filling phase containing a fugitive substance is disclosed. Replacement of the fugitive substance with a gas is further disclosed. Gas-filled porous particles and their aqueous dispersions are also disclosed.

Abstract: A process is provided for preparing a mixture of (1) a copolymer of a polyalkene and an unsaturated acidic reagent and (2) a polyalkenyl derivative of an unsaturated acidic reagent, said process comprising (a) copolymerizing (1) a polyalkene containing alkylvinylidene isomer and non-alkylvinylidene isomers and (2) an unsaturated acidic reagent under polymerization conditions in the presence of a free radical initiator; and (b) reacting the product of step (a) with an unsaturated acidic reagent at elevated temperature in the presence of a strong acid. The product of the process can be used to make polysuccinimides that are useful in lubricating oil compositions.

Abstract: The invention relates to a method for manufacturing a sealable and peelable polymer blend, in which method polystyrene and an ethylene copolymer are first melt blended and the obtained blend is further mixed with the same ethylene copolymer either by melt blending or dry blending so that the final polymer blend contains 1-50% by weight polystyrene and 99-50% by weight ethylene copolymer. Ethylene copolymer is preferably ethylene/methyl(meth)acrylate, ethylene/ethyl(meth)acrylate, ethylene/butyl(meth)acrylate or ethylene/vinylacetate copolymer.

Abstract: The melt strength is increased and the gloss level is reduced in olefinic TPE compositions through the addition of sufficient amounts of free radical generators (A) and co-curative agents (B). The free radical generators (A) include peroxides, organic peroxides, the persulfates, and the diazo compounds, and mixtures thereof. The co-curative agents (B) includes metal salts of alpha, beta-unsaturated carboxylic acids and alpha, beta-unsaturated carboxylic acids where the pending acid group has been neutralized, or mixtures thereof, and the metals for forming the metal salts of co-curative agent (B) include zinc, lithium, calcium, magnesium, sodium or aluminum, or mixtures thereof.

Abstract: The present invention relates to novel compositions useful in coating, adhesive, structural, film, sheet, pipe, toys, house siding, asphalt, thermoplastic, elastomer and other applications. The novel compositions comprise copolymers of at least one vinyl and/or vinylidene monomer and at least one high reactivity polyolefin. The copolymers are produced by polymerizing at least one high reactivity polyolefin and at least one vinyl monomer in the presence of a free radical initiator.

Abstract: A method of preparing a liquid ink or liquid toner for printing including the steps of dispersing a monomer in a carrier fluid and a polymerization stabilizer comprising a multi or single functional group containing polysiloxane, and in situ polymerizing the monomer to form uniform polymer particles dispersed in the carrier fluid. The multi or single functional group on the polysiloxane is amino, carboxylic acid, vinyl and hydroxyl.

Abstract: The present invention is directed to a method for producing a copolymer and a copolymer product of the method. The copolymer is prepared by a controlled radical polymerization process, typically an atom transfer radical polymerization process, in which polymerizable alkene monomers are polymerized in the presence of a halogenated polyolefin macroinitiator. The copolymer product of this process is useful in a film-forming composition that adheres strongly to polyolefinic substrates and to which non-polyolefinic film-forming compositions strongly adhere. The copolymer can be applied to a substrate in an adhesion-promoting layer or can be incorporated into a film-forming composition, such as a primer, that contains additional resinous compounds.

Abstract: Inherently tacky, pressure-sensitive adhesive compositions useful in marking film applications are provided. The compositions comprise polymer particles prepared by emulsion polymerization of at least one monomer mixture. The monomer mixture comprises at least one alkyl acrylate, the alkyl group of which has from about 4 to 12 carbon atoms, preferably in an amount of from about 73% to 90% by weight, at least one unsaturated carboxylic acid containing from about 3 to 5 carbon atoms, preferably in an amount of from about 2% to 12% by weight, and at least one hard monomer, preferably present in an amount of from about 5% to 15% by weight. The particles have a mean diameter of about 300 nm or less, as determined by laser light scattering. Preferably the hard monomer comprises a styrenic monomer, more preferably both a styrenic monomer and an alkyl methacrylate. In some embodiments, the compositions are prepared by sequential polymerization of the first and second monomer charges.

Abstract: Present invention is a resin composition obtained by reacting polyolefin (A) with a (co)polymer (B) prepared from a copolymerizable monomer mixture (C) comprising an &agr;,&bgr;-monoethylenically unsaturated monomer and other copolymerizable monomers in a weight ratio (A)/(B)=1/9-9/1 under radical generation in an organic solvent, or by polymerizing a copolymerizable monomer mixture (C) comprising an &agr;,&bgr;-monoethylenically unsaturated monomer and other copolymerizable monomers in the presence of polyolefin (A) in a weight ratio (A)/(C)=1/9-9/1 in an organic solvent and successively by reacting the obtained reaction mass under radical generation; and the resin composition has good solution stability, does not cause liquid phase separation or solid precipitation, can be used as intact, is excellent in sprayability at high concentration, and, specifically, has novel function and effect that adhesion to polyolefin molded articles is excellent; and the resin composition can be favorably used f

Abstract: The residual chlorine content of a polyolefin-substituted carboxylic acylating agent formed by a chlorine-assisted reaction of a polyolefin and an &agr;,&bgr;-unsaturated carboxylic reactant can be reduced by heating the polyolefin-substituted carboxylic acylating agent having a residual chlorine content in the presence of an &agr;,&bgr;-unsaturated carboxylic reactant, optionally in the further presence of a sulfonic acid. Residual chlorine content can be further reduced by using, in the reaction of the polyolefin &agr;,&bgr;-unsaturated carboxylic reactant, a high speed mixer provided with a dual pitch blade.

Abstract: Porous polyolefins are especially efficiently free-radically grafted using (fluorinated alkyl)olefins, vinylsilanes or certain carboxylic acids or their esters as the grafting molecules. The use of a solvent to swell the porous polyolefin is sometimes advantageous.

Abstract: The invention provides a novel binder resin composition. A binder resin composition characterized by comprising carboxyl group-containing chlorinated syndiotactic polyolefin resin with chlorine content of 0.1 to 40 wt. %, grafting level of &agr;,&bgr;-unsaturated carboxylic acid and/or its acid anhydride of 10 wt. % and weight average molecular weight of 30000 to 220000 and organic solvent. The carboxyl group-containing chlorinated syndiotactic polyolefin obtainable from polyolefin resin produced using metallocene compound exhibits good state of solution even if the chlorine content may be low, and is excellent in the adherence to polyolefinic prime material and the solvent resistance.

Abstract: A polymeric film composition, which can readily be applied to a sheet-configured substrate and which resists creep at room temperature, even when the sheet/film combination is stored as a roll, is disclosed. The polymeric film composition has a viscosity of at least 3×106 Pa-s at a predetermined first lower temperature and at a shear stress of 10,000 Pa and a viscosity no greater than 1×104 Pa-s at a predetermined second higher temperature and at a shear stress of 50,000 Pa.

Abstract: A method of preparing a curable coating and a method of curing the curable coating are disclosed. The curable composition from which the curable coating is prepared may be applied to the surface of a substrate in neat form or in aqueous medium to produce the coating. Curing of the curable coating may be accomplished by chemical generation of free radicals, by electrochemical generation of free radicals, by electron beam, by photochemical generation of free radicals, or by other electromagnetic irradiation.

Abstract: A process for preparing a block copolymer. In one embodiment, the block copolymers comprise (A) a poly (vinyl aromatic) block and (B) a poly (vinyl aromatic-co-acrylic) block, said process comprising the steps, (a) polymerizing at an elevated temperature from about 5 to about 95 mole % of a charge comprising at least one vinyl aromatic monomer to prepare a stabilized active polymer block (A), using a free radical polymerization process, wherein a stable free radical agent is employed during the polymerization, thereby preserving the stabilized active polymerization site at the terminus of the poly (vinyl aromatic) block (A); (b) adding at least one acrylic monomer and optionally, additional vinyl aromatic monomer, to the mixture of vinyl aromatic monomer and stabilized active polymer block of (a); and (c) further reacting the mixture of (b) using a free radical process to effect copolymerization of said monomers, thereby preparing a (vinyl aromatic-co-acrylate) block (B).

Abstract: A composition, comprising, in a physiologically acceptable medium, at least one polymer with a highly specific ordered structure is disclosed. These compositions find a specific application in the field of caring for or making up keratinous fibers, in particular as a mascara composition for the eyelashes or for the hair.

Abstract: The present invention relates to high melt swell partially neutralized alpha olefin acid copolymers. It also relates to a process for making such high melt swell polymers as well as for covalently crosslinking other polar copolymers including non-neutralized acid copolymers and non-polar alpha olefin polymers by using a minor amount of metal acrylate, particularly sodium or zinc acrylate.

Abstract: A superabsorbent polymer comprising a delayed absorption superabsorbent polymer having a free water absorbency property of absorbing less than about 3 grams of aqueous saline per gram of superabsorbent polymer in about 6 seconds, for a full particle size distribution of superabsorbent polymer ranging from about 40 micrometers to about 890 micrometers.

Abstract: A highly water resistant tackifier resin comprising an acrylic (co)polymer incorporating therein while taking up at least part of a tackifying component as a raw material on or around seed particles of 0.05 to 15 &mgr;m in average particle size having polar groups on their surfaces. The above tackifier resin can be produced by a process comprising the steps of: dispersing a tackifying component as a raw material, an oil-soluble peroxide or oil-soluble azo initiator and an acrylic monomer in an aqueous medium in which seed particles of 0.05 to 15 &mgr;m in average particle size having polar groups at their surfaces are dispersed; and polymerizing the acrylic monomer while at least part of the tackifying component is incorporated in the acrylic (co)polymer on or around the seed particles so that the seed particles grow.

Abstract: The molecular weight of a graft copolymer is reduced by carrying out the following steps in a non-oxidizing atmosphere: (1) treating a propylene polymer material with an organic compound that is a free radical polymerization initiator, (2) treating the propylene polymer material with about 2 to about 240 parts per hundred parts of the propylene polymer material, of at least one vinyl-substituted grafting monomer in the presence of about 0.5% to about 5% of a polymerizable chain transfer agent that is a derivative of allyl alcohol, and (3) removing any unreacted monomer, decomposing any unreacted initiator, and deactivating any residual free radicals in the material.

Abstract: A novel chlorine-free modified polyolefin resin composition with excellent adherence to nonpolar substrates, excellent solubility in solvents, excellent compatibility with other resins, and without tack after painting and drying is obtainable by graft modifying a mixed resin having 40 to 99 parts by weight of polyolefin resin (A) and 1 to 60 parts by weight of ethylenic compound-unsaturated carboxylic acid copolymer (B) that contains 0.1 to 50% by weight of unsaturated carboxylic acid derivative, with unsaturated carboxylic acid derivative and/or its anhydride (C), the modified polyolefin resin composition having weight average molecular weight of 20,000 to 150 000 and the grafting weight of (C) being 0.1 to 20% by weight.

Abstract: The present invention provides a one-piece golf ball having good durability, good shot feel and excellent flight performance. The present invention relates to a one-piece golf ball formed by vulcanizing and press molding a rubber composition comprising a base rubber, co-crosslinking agent, organic peroxide and inorganic filler, wherein the base rubber comprises (1) polybutadiene (A) having a weight average molecular weight (Mw) of 55×104 to 69×104 and a number average molecular weight (Mn) of 10×104 to 20×104, and (2) polybutadiene (B) having a weight average molecular weight (Mw) of 70×104 to 120×104 and a number average molecular weight (Mn) of 13×104 to 25×104, in a weight ratio (A/B) of 3/97 to 70/30.

Abstract: A vinyl polymer having, at a molecular chain terminus, a structure represented by the general formula 1: (wherein R3 is a hydroxy, amino, epoxy, carboxylic acid, ester, ether, amide or silyl group, an alkenyl group having low polymerizability, an organic compound having 1 to 20 carbon atoms, X is a halogen atom, a nitroxide or sulfide group or a cobalt porphyrin complex).

Abstract: The invention relates to a curable composition and a process of preparing the curable composition. The process comprises (a) forming an oligomer from oligomerization of a mixture of a monomer A having a functional group and a monomer B at a temperature in the range of from 150° C. to 650° C., a pressure in the range of from 3 MPa to 35 MPa and the pressure is high enough to maintain the reaction mixture in a fluid state and a residence time in the range of from 0.1 second to 4 minutes; and (b) reacting a modifier having at least one reactive moiety with the oligomer through a reaction between the reactive moiety of the modifier and the functional group of the monomer A in the oligomer, and the modifier further comprises a curable group.

Abstract: The present invention relates to water-borne ceramer compositions capable of being cured to form antistatic, abrasion resistant ceramers. The ceramer compositions comprise water having dispersed or dissolved therein a plurality of colloidal silica particles, a binder precursor, and an electrically conductive organic polymer. The present invention also relates to ceramer articles, for example, ceramer coatings and shaped ceramer particles made from the ceramer compositions and to methods of making the ceramer compositions and ceramer articles.

Abstract: The invention is concerned with water soluble high-molecular weight quaternary ammonium graft polymer, wherein ammonium salt side chains are grafted onto a polyamine backbone under free radical conditions, and wherein the initiator system comprises a free radical-producing oxidizing agent and the polyamine backbone polymer.

Abstract: The invention relates to polyolefin copolymers (I) and to graft copolymers (II) which are prepared from the copolymers (I), wherein the copolymers (I) are linear copolymers containing divinylbenzene comonomer units selected from the group consisting of 1,4-divinylbenzene units, mixtures of 1,4- and 1,3-divinylbenzene units and mixtures of 1,4-, 1,3- and 1,2-divinylbenzene units, wherein R, in formulas I and II, is a C1 to C10 linear or branched alkyl group or a C6 to C10 substituted or unsubstituted aromatic group; and wherein G and G′, independently, are selected from —H, —OH, epoxy, —NH2, —COOH, anhydride, —Cl, —Br, —M, —COOM (M=metal) or a polymer chain having the molecular weight of at least about 500, which can be derived from both step and chain polymerization reactions. In the graft copolymer (II), the combined alpha-olefin mole % (x+y) is from about 50 and 99.

Abstract: Provided are a rubber composition for injection molding with which it is possible to prevent scorching by ensuring the fluidity of the rubber composition needed for injection molding to suppress a temperature rise of the composition in an injection cylinder, without impairing the performance characteristics of a vulcanized product, as well as a golf ball using the rubber composition and its producing method. The rubber composition for injection molding includes a diene rubber, a crosslinking agent, an &agr;, &bgr;-unsaturated carboxylic acid and/or metal salt thereof, and &agr;, &bgr;-unsaturated carboxylic alkylester. The ratio of the total amount of the unsaturated carboxylic acid and the metal salt to the content of the alkylester ranges from 1.0 to 12.

Abstract: The present invention relates to a novel photosensitive resin which can be developed in water and which can be used as a photosensitive resin composition. More specifically, the present invention relates to a composition which is useful as a photosensitive soldering resist for printed circuit board.

Abstract: An esterified macromonomer within the scope of the general formula: wherein Z is an organic moiety, R1 is hydrogen or a substituted or unsubstituted alkyl having from 1 to 12 carbon atoms, oxyalkyl having from 1 to 12 carbon atoms, alkenyl having from 2 to 12 carbon atoms, cycloalkyl having from 5 to 12 carbon atoms, aryl having from 6 to 12 carbon atoms or aralkyl having from 7 to 12 carbon atoms, each E independently is a hydroxyl group, an organic ester moiety or an inorganic ester containing moiety and at least one E is an ester containing moiety, n and m each independently is an integer from 2 to 12.

Abstract: This invention relates to multiphase structured polymer particles comprising at least two rubber component phases (I) formed by copolymerization of monomer mixtures comprising an acrylate ester and a polyfunctional monomer, a thermoplastic resin component phase (II) formed by copolymerization of a monomer mixture comprising a methacrylate ester and other monomers, and satisfying the following conditions (1)-(5). (1) The number average molecular weight of the thermoplastic resin component forming the outermost phase is 30,000 or less. (2) The weight ratio of phase (I)/phase (II) is 30/70-80/20. (3) Of the adjacent phases (1), a specific relation holds regarding the solubility in water of the monomer mixtures forming the nth and n+1th phases. (4) A specific relation holds between the refractive index of phase (I) and the refractive index of phase (II). (5) The average particle size is 150 nm or less.

Abstract: The invention relates to water-soluble block copolymers comprising at least one block of hydrophobic nature and at least one block of hydrophilic nature, the block of hydrophobic nature exhibiting hydrophilic units in an amount of between 33% and 99% by weight with respect to the total weight of the units of the hydrophobic block. These copolymers are preferably diblocks or triblocks and are prepared by a polymerization process referred to as a living or controlled. Control of their hydrophilic-lipophilic balance makes it possible to adjust their solubility in water and their self-association properties. These copolymers can be used in particular as adhesion agents or wetting agents.

Abstract: A water dispersed primer composition comprising a solution of a halogenated hydrocarbon polymer in organic solvent; and a dispersing agent added to the solution to form a fluid primer to be dispersed in water to provide the water dispersed primer composition. Optionally, fluid primers may include photoreactive components to provide photoreactive water dispersed primer compositions. The invention further includes water based priming adhesive compositions comprising an adhesive dispersion of an adhesive polymer dispersed in water, and a primer mixed with the adhesive dispersion to form the priming adhesive.

Abstract: A method for preparing a dispersion for a pressure sensitive adhesive is provided, wherein the dispersions contain a copolymer (CP) having units of butyl acrylate and meth)acrylic acid; the method involving the steps of polymerizing an aqueous emulsion (EM) containing butyl acrylate, an anionic emulsifier and a non-ionic emulsifier, in the aqueous phase, under heating and in the presence of at least one water-soluble initiator (IN) of formula (I) MR1  (I) where M represents a metal cation, and R1 represents an anion of a peroxyacid or azo-group-containing acid, wherein (IN) is present in an amount of 0.5-1.5 wt. % (based on weight of the monomers); emulsifying-in (meth)acrylic acid while maintaining an elevated reaction temperature; and adding a second initiator (RI) to complete the polymerization.

Abstract: Ethylene copolymer elastomer compositions, acrylate rubber compositions, nitrile rubber compositions, fluoroelastomer compositions, and chlorinated elastomer compositions are provided which are curable by exposure to UV radiation. The compositions are particularly suited for production of elastomeric seals using hot melt equipment and a gasketing in place technique.

Abstract: The invention relates to reactive polysols with a reactive monomer portion which is polymerized during thermal coating. The polysols exhibit good mechanical properties. A monofunctional (meth)acrylate monomer of formula (1) is used as reactive monomer component.

Abstract: An acrylic polymer powdery material, which is a particularly useful powdery material as a modifier for cementitious material, comprising fine particles of a core-shell structure comprising a core polymer being comprised of an acrylic polymer having a glass transition temperature (Tg) of −20-+15° C., a weight average molecular weight of 100000-2000000, an acid value of 25 mg KOH/g or less and a shell polymer being comprised of an acrylic polymer having a Tg of 50-90° C., a weight average molecular weight of 100000-2000000, an acid value of 30-130 mg KOH/g, wherein the weight ratio of the core polymer and shell polymer is 30/70-80/20 (% by weight).