Abstract: A pressure sensitive adhesive optical film with a pressure sensitive adhesive layer laminated on at least one surface of an optical film, wherein the pressure sensitive adhesive layer has a value of no more than 5 N/25 mm for a P0 which is initial 90° peel strength at 23° C. and by a peeling speed of 300 mm/minute after an autoclave processing under a condition of 50° C.×5 atm×15 minutes, and a ratio (P1/P0) of a P1 to a P0 is no less than 2, which P1 is 90° peel strength after heating by a peeling speed of 300 mm/minute and at 23° C. after the pressure sensitive adhesive layer is given the above-mentioned autoclave processing and is furthermore given a heat-treatment at 80° C. for 2 hours.

Abstract: A pressure sensitive adhesive optical film that has good reworkability, and further has excellent moisture heat resistance, and that gives neither foaming nor peeling under heated and humidified treatment is provided.

Abstract: The surface-modified pressure-sensitive adhesive has a surface-modifying layer made of another polymer and physically fixed to a surface of the pressure-sensitive adhesive; and the method of modifying a surface of a pressure-sensitive adhesive includes the following steps (A) to (C):

Abstract: A finely foamed pressure-sensitive adhesive tape or sheet possessing a pressure-sensitive adhesive layer having a fine cell size and cell wall thickness is disclosed. The tape or sheet is obtained by impregnating the pressure-sensitive adhesive tape or sheet with carbon dioxide in a liquid state or a supercritical state, and reducing the pressure to foam the pressure-sensitive adhesive layer. The main component of the pressure-sensitive adhesive layer is, for example, an acrylic resin or a rubber-based resin. The method provides a finely foamed pressure-sensitive adhesive tape or resin possessing a pressure-sensitive adhesive layer having a fine cell structure such that an average cell size d is from 0.01 to 1000 &mgr;m, an average cell wall thickness t is from 0.01 to 2000 &mgr;m, and the ratio t/d is in the range of from 0.5 to 3.5.

Abstract: A process for producing a natural rubber for a pressure-sensitive adhesive, which comprises decreasing a molecular weight of an unmasticated natural rubber by the action of a peptizing agent while dissolving the unmasticated natural rubber in an organic solvent, and a natural rubber-based pressure-sensitive adhesive composition comprising a natural rubber having a weigh average molecular weight Mw of 700,000 or less obtained by the process.

Abstract: An acrylic pressure-sensitive adhesive composition which contains a high molecular weight polymer, is excellent in cohesive force and adhesive strength and can be prepared without using an organic solvent. The acrylic pressure-sensitive adhesive composition is produced by a process which comprises radical-polymerizing monomers containing an alkyl (meth)acrylate using carbon dioxide as a diluent to thereby prepare a pressure-sensitive adhesive composition containing an acrylic polymer having a weight average molecular weight of 400,000 or more. The polymerization pressure ranges from, for example, about 5.7 to 40 MPa, AND the polymerization temperature ranges from, for example, about 20 to 100° C.

Abstract: A microporous soundproofing material constituted of an expanded material formed through the step of impregnating a thermoplastic elastomer with an inert gas at a high pressure and then decompressing the impregnated elastomer. The soundproofing material has a high characteristic impedance, is clean and lightweight, and has excellent flexibility. This microporous soundproofing material includes: a microporous soundproofing material which is constituted of an expanded material formed through the step of impregnating an unexpanded molding comprising a thermoplastic elastomer with an inert gas at a high pressure and then decompressing the impregnated molding; and a microporous soundproofing material which is constituted of an expanded material formed by impregnating a molten thermoplastic elastomer with an inert gas at a high pressure and then subjecting the impregnated elastomer to molding simultaneously with decompression.

Abstract: A process for producing a natural rubber for a pressure-sensitive adhesive, which comprises decreasing a molecular weight of an unmasticated natural rubber by the action of a peptizing agent while dissolving the unmasticated natural rubber in an organic solvent, and a natural rubber-based pressure-sensitive adhesive composition comprising a natural rubber having a weigh average molecular weight Mw of 700,000 or less obtained by the process.

Abstract: A method and apparatus for producing a foamed pressure-sensitive adhesive tape or sheet having a fine cell structure with a good production efficiency without through complicated steps are provided. The method comprises subjecting a mixture containing monomers of a polymer constituting a foamed pressure-sensitive adhesive layer to polymerization in an inert fluid in a supercritical state or a liquid state under pressure, and ejecting the polymerized composition obtained on a substrate under a pressure lower than the pressure in the polymerization to form a foamed pressure-sensitive adhesive layer applied on the substrate. The apparatus comprises a pressure vessel for polymerizing monomers of a polymer constituting a foamed pressure-sensitive adhesive layer under pressure, an inert fluid supplying means for supplying an inert fluid in a supercritical state or a liquid state to the pressure vessel, and an ejection means for ejecting the polymerized composition obtained by polymerizing the monomers.

Abstract: A modification method of functional group on the surface of a pressure-sensitive adhesive by fixing a functional group to the surface of the pressure-sensitive adhesive by an interfacial contact reaction between the pressure-sensitive adhesive phase and the phase containing a functional group-containing compound.By the modification method, a functional group effective for the improvement and control of an adhesive property can stably be introduced at high density to the surface of the pressure-sensitive adhesive.

Abstract: A method for tackifying the surface of a soft layer, which comprises tackifying the surface of the soft layer by an interfacial contact reaction between the soft layer or a reactive interlayer provided thereon, and a pressure-sensitive adhesive layer. Since sufficient adhesion can be obtained with a reduced thickness of the pressure-sensitive adhesive layer, the merits of the soft layer are not impaired.

Abstract: A treatment method for surface energy reduction is disclosed, which comprises subjecting a substrate to an interfacial contact reaction between the phase thereof and a phase containing a compound having at least one low-energy functional group to fix the low-energy functional groups to the substrate surface to thereby reduce the surface energy thereof. The method necessitates neither an expensive special solvent nor a curing step causing mechanical damage to the substrate, and can be carried out under simple conditions.

Abstract: A curable silicone-based release agent which comprises 100 parts by weight of a polyorganosiloxane and from 0.1 to 1,000 parts by weight of resin fine particles which are readily swellable or soluble in an organic solvent, said release agent being capable of forming a cured film having an oil-based ink adsorbing property.

Abstract: A pressure-sensitive adhesive composition comprising as a base polymer a mixed block copolymer comprising a polymer block of a monovinyl-substituted aromatic compound and a polymer block of a conjugated diene compound. The pressure-sensitive adhesive composition is useful to seal, for example, corrugated board or carton.