Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1998-10-20
2001-02-27
Niland, Patrick D. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S403000, C525S408000, C525S440030, C525S454000
Reexamination Certificate
active
06194523
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an adhesive resin composition and an adhesive film. More particularly, the present invention relates to an adhesive resin composition and an adhesive film that maintain thermoplastic property at normal temperature, thereby permitting molding and processing, and that undergo rapid curing at a temperature beyond a certain temperature to afford superior heat resistance and superior water resistance.
BACKGROUND OF THE INVENTION
Various thermoplastic resins have been used in a broad range of fields in recent years. Thermoplastic resins are superior in solubility in solvents and heat seal property, but inferior in heat resistance. For an improved heat resistance, a two-part adhesive comprising a thermoplastic resin and a curing agent has been used. However, a two-part adhesive has a limited working life (pot life). To provide an adhesive resin composition having relatively long pot life and capable of thermosetting, an epoxy resin as a main component and other ingredients are used in various combinations. For example, such combinations are used as an adhesive for circuit board. The adhesive for this use is required to have not only adhesive property but also superior heat resistance, chemical resistance, flexibility, electric insulating property and the like. Heretofore, poly(vinyl butyral) resin-epoxy resin type adhesive compositions, acrylonitrile-butadiene rubber-epoxy resin type adhesive compositions and adhesive compositions comprising phenol resin or acrylic rubber as a main component have been widely used. However, poly(vinyl butyral) resin-epoxy resin type adhesive compositions are inferior in the most desired adhesive property and other adhesive compositions mentioned above are inferior in heat resistance.
In case of a copper clad laminate for print circuit, the portion of the copper foil to form a conductive part that is other than the circuit part is chemically etched to give a wire board and the circuit board is perforated so that terminals for connection to electric parts can be formed. During this process, it is required that the board be free of blister when it is immersed in a molten solder bath (chemical resistance), and an adhesive film be free of peeling off when the chemical used for soldering is washed away with water (water resistance).
The adhesive composition for the above-mentioned use is required to have relatively long working life and superior properties of heat resistance, chemical resistance, flexibility, electrical insulating property and the like, besides adhesive property. Conventional adhesive compositions for use heretofore that contain a thermoplastic resin have insufficient heat resistance, and those containing a thermosetting resin have insufficient flexibility and shorter working life (pot life).
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an adhesive resin composition superior in heat resistance and water resistance. The present invention now provides an adhesive resin composition comprising an epoxy resin and a polyester polyurethane containing less amount of a low molecular weight component in combination, and an adhesive film obtained from said adhesive resin composition.
Accordingly, the present invention provides the following.
(1) An adhesive resin composition comprising a polyester polyurethane having a number average molecular weight of 8,000-100,000 and an epoxy resin having two or more epoxy groups per molecule, said polyester polyurethane having an acid value of 100-1,000 equivalent/10
6
g and the proportion of polyester polyurethane having a molecular weight of not more than 5,000 being not more than 20 wt %.
(2) The adhesive resin composition of (1) above, wherein the polyester polyurethane comprises a polyester polyol component having a number average molecular weight of 5,000-50,000 in a proportion of not less than 60 wt %.
(3) The adhesive resin composition of (2) above, wherein the polyester polyol component comprises a dicarboxylic acid component comprising an aromatic dicarboxylic acid in a proportion of not less than 30 mol %.
(4) The adhesive resin composition of (1) above, wherein the polyester polyurethane comprises a polyester polyol comprising, as a constituent component, at least one dicarboxylic acid selected from the group consisting of terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid and adipic acid.
(5) The adhesive resin composition of (1) above, wherein the polyester polyurethane comprises a polyester polyol comprising, as a constituent component, at least one glycol selected from the group consisting of ethylene glycol, propylene glycol, 2-methyl-1,3-propanediol, diethylene glycol, neopentyl glycol and 1,4-cyclohexanedimethanol.
(6) The adhesive resin composition of (1) above, wherein the polyester polyurethane comprises, as a constituent component, at least one organic diisocyanate selected from the group consisting of 4,4′-diphenylmethane diisocyanate, hexamethylene diisocyanate and isophorone diisocyanate.
(7) The adhesive resin composition of (1) above, having an equivalent ratio of (the carboxyl group contained in the polyester polyurethane):(the epoxy group contained in the epoxy resin) of 1:0.5-1:5.
(8) An adhesive film obtained from the adhesive resin composition of (1) above.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides an adhesive resin composition and an adhesive film superior in adhesive property, heat resistance and water resistance, which have a long working life due to the use of polyester polyurethane comprising a less amount of a low molecular weight component.
The polyester polyurethane to bee used in the present invention preferably has a number average molecular weight of from 8,000 to 100,000. It is preferable that polyester polyurethane having a molecular weight of not more than 5,000 be contained in a proportion of not more than 20 wt % of the entire polyester polyurethane. When the proportion of polyester polyurethane having a molecular weight of not more than 5,000 exceeds 20 wt %, curing proceeds even an normal temperature, thus necessitating low temperature storage and consumption in a short period of time, and heat resistance after curing becomes poor.
The polyester polyurethane to be used in the present invention comprises a polyester polyol component and an organic diisocyanate component, wherein the polyester polyol comprises a dicarboxylic acid component and a glycol component. It is particularly preferable for superior adhesive property and heat resistance that not less than 30 mol % of the dicarboxylic acid component be an aromatic dicarboxylic acid and not less than 60 wt % of polyester polyurethane be a polyester polyol component having a number average molecular weight of 5,000-50,000.
Polyester Polyol Component
The polyester polyol component to be used in the present invention comprises a dicarboxylic acid component and a glycol component. Where necessary, a polyvalent carboxylic acid having a valence of 3 or more and/or a polyhydric alcohol having a valence of 3 or more may be added as a branch agent. The dicarboxylic acid component to be used in the present invention preferably contains an aromatic dicarboxylic acid in not less than 30 mol %. When it is less than 30 mol %, water resistance and heat resistance are degraded. The number average molecular weight of the polyester polyol component is preferably 5,000-50,000.
The dicarboxylic acid component constituting the polyester polyol to be used in the present invention is exemplified by aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, 2,2′-biphenyldicarboxylic acid, 4,4′-diphenyl ether dicarboxylic acid and the like, and aliphatic and alicyclic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexaned
Emoto Katsuya
Hattori Takahiro
Murata Masaki
Foley & Lardner
Niland Patrick D.
Toyo Boseki Kabushiki Kaisha
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