Stock material or miscellaneous articles – Composite – Of epoxy ether
Reexamination Certificate
2002-02-13
2004-04-13
Dawson, Robert (Department: 1712)
Stock material or miscellaneous articles
Composite
Of epoxy ether
C428S413000, C428S414000, C428S418000, C428S901000, C528S087000, C528S088000, C523S400000, C523S435000, C252S601000, C252S609000
Reexamination Certificate
active
06720077
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a resin composition, an electrically insulating prepreg, laminate and printed-wiring board using the resin composition, and methods for their production. The laminate referred to in the present invention includes a laminate one or both surfaces of which are clad with a metal foil, namely a metal-clad laminate.
BACKGROUND ART
In recent years, because of increasing concern about environmental problems, prepregs, laminates and printed-wiring boards for electrical insulation have been desired to release no harmful substances to the environment during their disposal or incinerate. Therefore, for the prevention of the so-called dioxin problem during their incinerate, the number of products characterized by containing no halogen-containing flame retarder is increasing. As a flame retarder that can substitute for the halogen-containing flame retarder, flame retarders of metal hydroxide type, phosphorus type, melamine-modified resin type and so on are employed and, especially, phosphorus-containing flame retarders are useful because a great flame retarding effect can be obtained by their use even in a small amount.
However, compounds practically used as a phosphorus-containing flame retarder include red phosphorus, phosphoric acid salts, phosphoric esters and so on. They have problems such as releasing harmful phosphine gas during their incinerate or reducing heat resistance or chemical resistance of laminates, printed-wiring boards and the like through their hydrolysis. With respect to such problems, JP-A Nos. 4-11662 and 2000-80251 disclose a reaction product resulting from an epoxy resin and an organophosphorus compound having a structure different from phosphoric esters and containing in its molecule a phenolic hydroxyl group capable of reacting easily with an epoxy resin. It is reported that this reaction product does not reduce heat resistance or chemical resistance and that flame-retardant resin compositions, laminates and printed-wiring boards containing no halogen-containing flame retarders can be produced using that reaction product. However, with respect to the reaction product resulting from an epoxy resin and an organophosphorus compound having a phenolic hydroxyl group disclosed in those patent publications, both of the epoxy resin and the organophosphorus compound are polyfunctional and, therefore, crosslinking structure easily occurs in the reaction product, it is very difficult to control their reactivity. Further, since an epoxy group is consumed when the epoxy resin and the organophosphorus compound react together, there are problems, with the reaction product, of having a very large epoxy equivalent and having a reduced curability.
Under these circumstances, an object of the present invention is to provide a resin composition that has enough flame retardancy without containing any halogen-containing flame retarder, has good heat resistance and good chemical resistance, and causes no problems with respect to reaction stability or curability caused by consumption of an epoxy resin through a reaction occurring during compounding of the resin composition. Another object of the present invention is to provide a prepreg, laminate and printed-wiring board using this resin composition and to provide methods for their production.
DISCLOSURE OF THE INVENTION
The inventors of the present invention investigated earnestly to attain the above objects and have found the invention below. That is, the present invention is directed to a resin composition comprising:
an epoxy resin,
an amine-type curing agent,
an organophosphorus compound having a structure represented by formula 1:
Wherein R1 is an aryl radical with two hydroxyl groups, and the aryl radical can be substituted by one to three lower alkyls, preferably R1 is one of the radical selected from the group:
and
an organic solvent,
wherein the epoxy resin and the organophosphorus compound have been compounded at a temperature of 50° C. or lower. Further, the present invention is also directed to a prepreg, laminate and printed-wiring board using this resin composition, and to methods for their production.
BEST MODE FOR CARRYING OUT THE INVENTION
The resin composition of the present invention is characterized by being a composition in which a reaction between the epoxy resin and the organophosphorus compound represented by formula 1 is inhibited until the resin composition is used for preparation of prepregs. If a reaction between the epoxy resin and the organophosphorus compound represented by formula 1 occurs during their compounding, the epoxy equivalent weight will change, resulting in a large variation in gelation time of the resin and an unstable curability. To control the reactivity of the two ingredients during their compounding, it is necessary to keep the temperature at 50° C. or lower during the compounding step. Whether a reaction is taking place between the epoxy resin and the organophosphorus compound can be confirmed using a general-purpose analyzer such as high-performance liquid chromatography.
Examples of the epoxy resin contained in the resin composition of the present invention include bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, bisphenol S-type epoxy resin, biphenyl-type epoxy resin, naphthalenediol-type epoxy resin, phenol-novolak-type epoxy resin, cresol-novolak-type epoxy resin, alicyclic epoxy resin, glycidyl ester resin, glycidyl amine resin, heterocyclic epoxy resin such as triglycidylisocyanurate and diglycidylhydantoin, and modified epoxy resins resulting from modification of these epoxy resins with various reactive monomers. Tetrakis(glycidyloxyphenyl)ethane can also be employed.
These epoxy resins can be used alone or, alternatively, two or more kinds of epoxy resins can be employed in suitable combination. Especially, phenol-novolak-type epoxy resin, cresol-novolak-type epoxy resin and dicyclopentadiene-modified novolak epoxy resin are preferable because high heat resistance and high reliability are required for electric and electronic material applications. It is desirable to use at least one of the three types of epoxy resins in an amount of 30 wt % or more versus the combined amount of the whole epoxy resin.
Examples of the amine-type curing agent that can be used include open-chain aliphatic amine such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, hexamethylenediamine, diethylaminopropylamine, dicyandiamide, tetramethylguanidine and triethanolamine; alicyclic amine such as isophoronediamine, diaminodicyclohexylmethane, bis(aminomethyl)cyclohexane, bis(4-amino-3-methyldicyclohexyl)methane, N-aminoethylpiperazine and 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5.5]undecane; and aromatic amine such as xylenediamine, phenylenediamine, diaminodiphenylmethane and diaminodiphenylsulfone.
These amine-type curing agents can be used alone or, alternatively, two or more kinds of amine-type curing agents can be employed in suitable combination. Especially, dicyandiamide is preferable from the viewpoints of curability and physical properties of cured products.
Examples of the organophosphorus compound having a structure represented by formula 1 include 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(2,5-dihydroxy-6-methylphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(2,5-dihydroxy-3-methylphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(2,5-dihydroxy-4-methylphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 10-(1,4-dihydroxy-2-naphthyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide. Especially, 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is preferable from the viewpoint of flame retardancy.
The compounding ratio of the epoxy resin, the amine-type curing agent, the organophosphorus compound having the structure represented by formula 1 and the organic solvent can be determined from the viewpoint of proper maintenance of the properties of cured products resulting from curing
Abe Norihiro
Hirai Yasuyuki
Kakitani Minoru
Kamoshida Shinichi
Oohori Kenichi
Antonelli Terry Stout & Kraus LLP
Dawson Robert
Feely Michael J
Hitachi Chemical Co. Ltd.
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