Nitto-denko Corporation

Masahiro Oura

Takao Yoshikawa

Shigeki Muta

Kazuyuki Kitakura

Kazuhito Hosokawa

Takahiro Nonaka

Hitoshi Takahira

Masahiko Ando

Shinji Inokuchi

Hiroaki Kishioka

Noritsugu Daigaku

Miyoko Ikishima

The present invention relates to a double-sided pressure-sensitive adhesive tape or sheet for wiring circuit board, which comprises a pressure-sensitive adhesive layer formed by a pressure-sensitive adhesive composition containing an acrylic polymer and a chain transfer substance, in which the pressure-sensitive adhesive layer has characteristics that a gel fraction in the initial stage is from 40 to 70% by weight, and a difference between a gel fraction (% by weight) of the pressure-sensitive adhesive layer after the following solder reflow step and the gel fraction (% by weight) of the pressure-sensitive adhesive layer in the initial stage is 10 or less. The solder reflow step satisfies the following heat treatment conditions. Surface temperature of the double-sided pressure-sensitive adhesive tape or sheet reaches 175&#xb1;10&#xb0; C. within 130 to 180 seconds, the surface temperature reaches 230&#xb1;10&#xb0; C. within 200 to 250 seconds, the surface temperature reaches 255&#xb1;15&#xb0; C. within 260 to 300 seconds and the solder reflow step finishes within 370 seconds after start of the solder reflow step for the double-sided pressure-sensitive adhesive tape or sheet.

Double-sided pressure-sensitive adhesive tape or sheet for wiring circuit board and wiring circuit board

The release liner includes a release layer constituted of at least one polyolefin resin, wherein the release layer has surface irregularities. The surface irregularities of the release layer may be constituted of recesses and protrusions which are irregularly different in shape and have been disposed in irregular arrangement. The release layer preferably has a surface roughness Ra of 1-3 &#x3bc;m. As the polyolefin resin constituting the release layer can be used at least one polyolefin resin selected from the group consisting of polyethylenes, polypropylene, polybutenes, poly(4-methyl-1-pentene), and copolymers of ethylene with one or more &#x3b1;-olefins having 3-10 carbon atoms.

Release liner and pressure-sensitive adhesive tape or sheet employing the same

A pressure-sensitive adhesive sheet prepared by coating a composition containing a) 100 parts by weight of monomers composed of from 70 to 100% by weight of a (meth)acrylic acid alkyl ester, said alkyl group having from 2 to 14 carbon atoms, and from 0 to 30% by weight of a monoethylenically unsaturated monomer copolymerizing therewith, b) from 0.1 to 5 parts by weight of a radical chain inhibitor, c) from 0.02 to 5 parts by weight of a polyfunctional (meth)acrylate as a crosslinking agent, d) from 0.005 to 1 part by weight of a photopolymerization initiator, and e) from 0.01 to 10 parts by weight of a silane coupling agent, on a releasing-treated film having a good surface smoothness and photopolymerizing the coated layer to form a pressure-sensitive adhesive layer having a haze value of 1% or lower and a total light transmission of at least 90%. The pressure-sensitive adhesive sheet is excellent in the transparency, the foaming resistance, the low out-gas property, and the discoloring resistance (heat resistance and weather resistance).

Pressure-sensitive adhesive sheets comprising photo-polymerization product and production method thereof

Adhesive sheets using an acrylic pressure-sensitive flame-retardant adhesive having excellent properties such as adhesive force and holding power at high temperature and also having a self fire-extinguishing property which instantaneously extinguishes fire, i.e., a flame-retardance, are provided. A photopolymerizable composition comprising a) 100 parts by weight of a monomer (or the oligomer thereof) comprising 70 to 100% by weight of a (meth)acrylic acid alkyl ester having on the average a carbon number of 2 to 14 in the alkyl group and 30 to 0% by weight of a monoethylenically unsaturated monomer copolymerizable with the ester, b) 0.02 to 5 parts by weight of a polyfunctional (meth)acrylate as a crosslinking agent, c) 0.01 to 5 parts by weight of a photopolymerization initiator, and d) 10 to 180 parts by weight of a flame retardant having a melting point of at least 60&deg; C. is prepared, a pressure-sensitive flame-retardant adhesive is prepared from the photopolymerized product of the composition, and the adhesive is formed on one or both surfaces of a substrate.

Photopolymerizable composition, pressure-sensitive flame-retardant adhesive, and adhesive sheets

An adhesive sheet not tacky at ordinary temperatures, exhibiting strong adhesion and high heat resistance by heating under low pressure for a short period of time, having no problem of adhesive protrusion and excellent in storage stability, which comprises a base material having provided on one side or both sides thereof at least one layer of a thermosetting adhesive comprising (1) a non-tacky polymer of a monomer mixture comprising from 70% to 99% by weight of a (meth)acrylic ester represented by formula (I), a homopolymer of which has a glass transition temperature of &minus;30&deg; C. or more, and from 1% to 30% by weight of a monoethylenic unsaturated monomer being copolymerizable therewith and having a functional group capable of reacting with an epoxy resin each based on the monomer mixture and (2) from 5 parts to 30 parts by weight of the epoxy resin per 100 parts by weight of the monomer mixture, and not substantially comprising a curing agent for the epoxy resin:

Thermosetting adhesive and adhesive sheet thereof

A thermosetting pressure-sensitive adhesive which can obtain the high rate of polymerization without a decrease in the molecular weight by photopolymerization, thereby show the tackiness at ordinary temperatures to permit easy temporary adhesion to an adherend, can be cured by heating for a short period of time to exhibit strong adhesive strength and high heat resistance, and is excellent in storage stability before heating, comprising a photopolymerized product of a composition comprising a) 100 parts by weight of a monomer mixture comprising 70% to 99% by weight of an alkyl (meth)acrylate whose alkyl group has 2 to 14 carbon atoms on average, and 1% to 30% by weight of a monoethylenic unsaturated acid copolymerizable therewith based on the monomer mixture, b) 0.01 part to 20 parts by weight of a cleavage type photopolymerization initiator having 3 or more peroxide groups in its one molecule, c) 5 parts to 30 parts by weight of an epoxy resin, and not substantially containing a curing agent for the epoxy resin as ingredient (c).

Thermosetting pressure-sensitive adhesive and adhesive sheet thereof

A peelable heat-conductive and pressure-sensitive adhesive is disclosed, which comprises: (a) 100 parts by weight of a polymer produced from a monomer mixture comprising from 70 to 100% by weight of one or more alkyl (meth)acrylates in which the alkyl groups on the average have 2 to 14 carbon atoms and from 0 to 30% by weight of one or more monoethylenic monomers copolymerizable therewith, each based on the amount of the monomer mixture; (b) from 20 to 400 parts by weight of a plasticizer having a boiling point of 150&deg; C. or higher; and (c) from 10 to 1,000 parts by weight of a heat-conductive filler. Also disclosed is an adhesive sheet comprising a substrate and, formed on one or each side thereof, a layer of the adhesive. The pressure-sensitive adhesive can exhibit tight adhesion during use and easy peeling after use.

Peelable heat-conductive and pressure-sensitive adhesive and adhesive sheet containing the same

The present invention provides a heat-conductive and pressure-sensitive adhesive sheet comprising an electrical insulating plastic film having formed on one or both of the surfaces thereof (1) at least one thin layer composed of an inorganic material selected from the group consisting of ceramics, metals and metal oxides other than ceramics, and (2) a pressure-sensitive adhesive composition layer formed on the thin layer. The heat-conductive and pressure-sensitive adhesive sheet is excellent in heat-conductivity and pressure-sensitivity, results in no trouble such as complicated procedures in the production process or worsened working environment, exhibits good adhesion between the base material and the pressure-sensitive adhesive composition layer, scarcely undergoes anchoring fracture between the base material even after allowing to stand at high temperatures for a long time, and has good heat resistance.

Heat-conductive and pressure-sensitive adhesive sheets and method for fixing electronic parts to heat-radiating members with the use of the same

Heat-conductive and pressure-sensitive adhesive sheets which are excellent in heat resistance, scarcely undergo anchoring fracture between the base material and the adhesive layer and, therefore, are usable in fixing electronic parts to heat-radiating members or fixing members in various fields including constructive materials, vehicles, aircrafts and ships. the heat-conductive and pressure-sensitive adhesive sheets are in the form of sheets, tapes, etc. wherein a layer of a heat-conductive and pressure-sensitive adhesive composition, which contains an alkyl (meth)acrylate polymer having hydrophilic groups, is formed on the high frequency sputter-etched surface(s) of a plastic film containing 2 to 50% by volume of a heat-conductive, electrical insulating filler.

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Osaka, Japan

Masahiro Oura