Abstract: The present invention relates to a pressure-sensitive adhesive tape or sheet having a light-reflective property and/or a light-shielding property, which comprises a base material and at least one pressure-sensitive adhesive layer disposed on at least one surface of the base material, in which the pressure-sensitive adhesive layer is formed by an acrylic pressure-sensitive adhesive composition containing an acrylic polymer (a) and a low-molecular weight polymer component (b) which contains, as a principal monomer component, an ethylenic unsaturated monomer having a glass transition temperature of from 60 to 190° C. when it is formed into a homopolymer and having a cyclic structure within the molecule thereof, and which has a weight-average molecular weight equal to or higher than 3,000 but lower than 20,000; in which the pressure-sensitive adhesive layer has a gel fraction of from 51 to 75 wt % and a temperature, at a maximum of loss tangent (tan ?), of from ?14 to 25° C.

Abstract: The adhesive composition of the present invention has a gel fraction of 20-50%, which comprises an acrylic polymer obtained by polymerizing a monomer mixture containing the following component (a) as a main component and the following component (b) in a proportion of 5-49 wt %: component (a): an alkyl (meth)acrylate wherein the alkyl group has 4 to 12 carbon atoms, component (b): a carboxyl group-containing monomer having a carboxyl group and an ethylenic unsaturated double bond, which affords, when polymerized, a homopolymer having a glass transition temperature of not more than 70° C. Since the adhesive composition of the present invention is superior in all of the adhesion, impact resistance and repulsion resistance, it can adhere even to a part having a coated film formed on a surface to be adhered.

Abstract: A transparent double-sided pressure-sensitive adhesive tape or sheet contains a transparent substrate and a transparent pressure-sensitive adhesive layer disposed on each side of the substrate, wherein the transparent pressure-sensitive adhesive layer disposed on at least one side of the transparent substrate is a layer formed from a pressure-sensitive adhesive composition containing a specific acrylic polymer (a) and a specific oligomer (b).

Abstract: A pressure-sensitive adhesive composition contains (a) an acrylic polymer containing an alkyl (meth)acrylate whose alkyl group has from 4 to 12 carbon atoms, as a monomer major component and from 1 to 10 parts by weight, based on 100 parts by weight of the whole of the monomer components, of a carboxyl group-containing monomer as a monomer component and having a weight average molecular weight of from 500,000 to 900,000; and (b) an oligomer containing an ethylenically unsaturated monomer, in which a homopolymer formed therefrom has a glass transition temperature of from 60 to 190° C. and which has a cyclic structure, as a monomer major component and from 1 to 10 parts by weight, based on 100 parts by weight of the whole of the monomer components, of a carboxyl group-containing monomer as a monomer component and having a weight average molecular weight of from 3,000 to 6,000.

Abstract: An aqueous dispersion type pressure-sensitive adhesive composition contains a polyalkylene glycol having a weight-average molecular weight of from 20,000 to 5,000,000 or at least one hydrophilic polymer selected from the group consisting of polyvinylpyrrolidone, poly(vinyl alcohol)s, and poly((meth)acrylic acid) in an amount of from 0.5 to 15 parts by weight per 100 parts by weight, on a solid basis, of the acrylic or rubber-based pressure-sensitive adhesive composition of the aqueous dispersion type; and a pressure-sensitive adhesive product contains a pressure-sensitive adhesive layer formed from the aqueous dispersion type pressure-sensitive adhesive composition.

Abstract: A pressure-sensitive adhesive composition contains (a) an acrylic polymer containing an alkyl (meth)acrylate whose alkyl group has from 4 to 12 carbon atoms, as a monomer major component and from 1 to 10 parts by weight, based on 100 parts by weight of the whole of the monomer components, of a carboxyl group-containing monomer as a monomer component and having a weight average molecular weight of from 500,000 to 900,000; and (b) an oligomer containing an ethylenically unsaturated monomer, in which a homopolymer formed therefrom has a glass transition temperature of from 60 to 190° C. and which has a cyclic structure, as a monomer major component and from 1 to 10 parts by weight, based on 100 parts by weight of the whole of the monomer components, of a carboxyl group-containing monomer as a monomer component and having a weight average molecular weight of from 3,000 to 6,000.

Abstract: A pressure-sensitive adhesive tape or sheet is characterized by having a substrate having a pressure-sensitive adhesive layer on at least one side thereof, wherein the whole of the pressure-sensitive adhesive layer is formed of an aqueous dispersion type pressure-sensitive adhesive composition containing, as a base polymer, (A) an acrylic polymer containing a (meth)acrylic acid C4-12 alkyl ester as the major monomer component; and in a surface portion of the pressure-sensitive adhesive layer within the range of up to 3 nm inward from the outer face of the pressure-sensitive adhesive layer, (B) an anionic emulsifier containing a sulfur atom is contained in a specific proportion, and (C) a hydrophilic polymer is contained in a specific proportion.

Abstract: An aqueous dispersion type pressure-sensitive adhesive composition contains an acrylic or rubber-based pressure-sensitive adhesive composition of the aqueous dispersion type and at least one hydrophilic polymer selected from the group consisting of polyalkylene glycols, polyvinylpyrrolidone, poly(vinyl alcohol)s, and poly((meth)acrylic acid), the amount of the hydrophilic polymer being from 0.5 to 15 parts by weight per 100 parts by weight, on a solid basis, of the acrylic or rubber-based pressure-sensitive adhesive composition of the aqueous dispersion type, and a pressure-sensitive adhesive product has a pressure-sensitive adhesive layer formed from the aqueous dispersion type pressure-sensitive adhesive composition.

Abstract: A sheet for forming a burned pattern is provided which comprises a ceramic green sheet layer (1) to be burned and a pressure-sensitive adhesive layer (2), wherein the pressure-sensitive adhesive layer comprises either a single layer decomposable at low temperature and leaving a decreased amount of carbonaceous residues after burning or a laminated layer comprising at least two layers of an inner pressure-sensitive adhesive layer (21) which is the low-temperature-decomposable layer and an outer pressure-sensitive adhesive layer (22) having resistance to water washing. The pressure-sensitive adhesive layer of the sheet for forming a burned pattern shows excellent provisional adhesion to adherends before burning. In particular, the outer pressure-sensitive adhesive layer shows such adhesive strength that the sheet is prevented from peeling off upon water washing.

Abstract: A process for producing an aqueous dispersion-type acrylic polymer is disclosed, which comprises introducing a monomer comprising an alkyl (meth)acrylate as the main component into a polymerization vessel at a time at a monomer concentration of 40% by weight or higher, adding a water-soluble radical polymerization initiator thereto in an amount of from 0.001 to 0.05 parts by weight per 100 parts by weight of the monomer, and emulsion-polymerizing the monomer substantially at 20.degree. to 60.degree. C. The aqueous dispersion-type acrylic polymer thus obtained satisfies the equation log M>3log S-2, wherein S is a tetrahydrofuran (THF)-soluble content (wt %) of the polymer and M is a weight-average molecular weight (.times.10,000) of a soluble part of the polymer. This polymer is preferably used for a pressure-sensitive adhesive in pressure-sensitive adhesive-covered products.