Insulating film

Details Insulating film Insulating film

2002-02-13

2003-12-30

Dawson, Robert (Department: 1712)

Stock material or miscellaneous articles

Composite

Of epoxy ether

C361S301100, C361S323000, C525S068000, C525S132000, C525S327300, C525S396000, C525S523000, C525S534000, C528S086000, C528S087000, C528S098000

Reexamination Certificate

active

06670042

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to insulating film which is excellent in heat resistance and electric insulating property and cheap.
2. Description of the Related Art
What is called super engineering plastics such as polyether sulfone, polyether ether ketone, polyether imide, polyamideimide and the like are widely used industrially as an insulating film because of excellent heat resistance and electric insulating property. However, there are indicated various problems such as extreme high price, insufficient molding processability in some cases, poor flexibility and the like.
On the other hand, regarding polyphenylene oxides, it is known that a resin composition composed of a polyphenylene oxide and a copolymer of an olefin and glycidyl methacrylate and/or glycidyl acrylate shows excellent impact resistance (JP-A No. 57-108153), and it is known that a resin composition composed of an amine-modified polyphenylene oxide and a copolymer of an ethylene and an unsaturated glycidyl carboxylate or unsaturated glycidyl ether can be used for films such as a film, sheet and the like (JP-A No. 7-102169).
However, it is not known that a resin composition obtained by using an un-modified polyphenylene oxide can be used for electric insulating film.
SUMMARY OF THE INVENTION
The present inventors have intensively studied to find an insulating film which is excellent in heat resistance and electric insulating property and additionally is cheap, and resultantly found that the object is attained even by a resin composition obtained by using an un-modified polyphenylene oxide, leading to completion of the invention.
Namely, the present invention provides industrially advantageous insulating film obtained by using a resin composition comprising (A) 100 parts by weight of a polyphenylene oxide having a structural unit of the following formula (1):
(wherein, R
1
and R
2
represent each independently hydrogen or a hydrocarbon group which may have a substituent and has 1 to 20 carbon atoms in total), and (B) 0.1 to 60 parts by weight of a copolymer having a functional group reactive with the above-mentioned polyphenylene oxide.
DETAILED DESCRIPTION OF THE INVENTION
The polyphenylene oxide which is a component (A) in the present invention has a structural unit of the above-mentioned formula (1), and this structural unit can be derived, for example, from at least one of phenol compounds of the following formula (2):
R
1
and R
2
represent each independently hydrogen or a hydrocarbon group which may have a substituent and has 1 to 20 carbon atoms in total, and examples of the hydrocarbon group include: alkyl groups having 1 to 20 carbon atoms in total such as a methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, t-butyl group, pentyl group, cyclopentyl group, hexyl group, cyclohexyl group, octyl group, decyl group and the like; aryl groups having 6 to 20 carbon atoms in total such as a phenyl group, 4-methylphenyl group, 1-naphthyl group, 2-naphthyl group and the like; aralkyl groups having 7 to 20 carbon atoms in total such as a benzyl group, 2-phenylethyl group, 1-phenylethyl group and the like; hydrocarbon groups having 1 to 20 carbon atoms in total having a substituent such as a trifluoromethyl group, 2-t-butyloxyethyl group, 3-diphenylaminopropyl group and the like.
Of them, R
1
and R
2
preferably represent hydrogen, methyl group and the like, and particularly, hydrogen is preferable.
The polyphenylene oxide which is a component (A) in the present invention may be a polymer of a phenol compound of the above-mentioned formula (2) or a copolymer of a phenol compound of the formula (2) with other phenol compounds, for example, poly-valent hydroxy aromatic compounds such as bisphenol-A, tetrabromobisphenol-A, resorcin, hydroquinone and novolak resins. In such copolymers, a structural unit of the formula (1) derived from the formula (2) is contained in an amount of preferably 80 mol % or more, more preferably 90 mol % or more.
The polyphenylene oxide which is a component (A) can be produced by oxidation-polymerizing the above-mentioned phenol compound with oxygen or oxygen-containing gas using an oxidation coupling catalyst. The oxidation coupling catalyst is not particularly restricted, and any catalyst having a polymerization ability can be used. For example, listed as typical examples thereof are catalysts containing cuprous chloride and catalysts containing di-valent manganese salts.
The component (A) in the present invention has an intrinsic viscosity [&eegr;] of preferably from 0.30 to 0.65, further preferably from 0.35 to 0.50 (25° C., chloroform solution). When [&eegr;] is less than 0.30, the heat resistance of a composition tends to decrease, and when over 0.65, the molding processability of a composition tends to lower, undesirably.
As the polyphenylene oxide, unmodified commercially available polyphenylene oxides are preferably used. Modification of these polymers is not preferred, because the reactive reagent for modification may react with the component (B) during the compounding process to cause uncontrolled reaction and produce fish eyes in the film made from the composition.
The insulating film of the present invention are obtained by using a resin composition composed of the above-mentioned component (A), polyphenylene oxide and the component (B), copolymer having a functional group reactive with the polyphenylene oxide, and the functional group reactive with the polyphenylene oxide may be permissible if it has reactivity with the component (A), and examples thereof include and oxazolyl group, epoxy group, amino group and the like. An epoxyl group is preferable. An epoxyl group and the like may exist also as a part of other functional groups, and a glycidyl group is mentioned as an example thereof.
In the copolymer which is component (B), as a method of introducing such a functional group into a copolymer, it is not limited especially and can be carry out by the well-known methods. For example, it is possible to introduce a monomer having this functional group by copolymerization in a preparation stage of the copolymer. It is also possible to conduct a graft copolymerization of a monomer having this functional group to a copolymer.
As the monomer having the functional group, a monomer containing a glycidyl group is used suitably. As the monomer containing a glycidyl group, unsaturated glycidyl carboxylate and unsaturated glycidyl ether represented by the following formula are preferably used,
In the formula, R is a hydrocarbon group of 2-18 carbons having an ethylenically unsaturated bond, and X is a group represented by —C(O)O—, —CH
2
—O— or
As the unsaturated glycidyl carboxylate, exemplified are, for example: glycidyl acrylate, glycidyl methacrylate, itaconic acid diglycidyl ester, butene tricarboxylic acid triglycidyl ester, p-styrene glycidyl carboxylate, etc.
As the unsaturated glycidyl ether, exemplified are, for example: vinyl glycidyl ether, allyl glycidyl ether, 2-methyl allyl glycidyl ether, methacryl glycidyl ether, styrene-p-glycidyl ether, etc.
The copolymer (B) having a functional group reactive with polyphenylene oxide desirably contains 0.1 to 20% by weight of a unsaturated glycidyl carboxylate unit and/or unsaturated glycidyl ether unit.
Moreover, in order to improve the heat stability and flexibility of the molded products by using the resin composition of the present invention, the heat of fusion of the crystal in the copolymer (B) is suitably less than 3 J/g. And the Mooney viscosity is suitably 3 to 70, more suitably 3 to 30, and especially suitably 4 to 25. Here, Mooney viscosity means the value measured using a large rotor at 100° C. according to JIS K6300.
The copolymer (B) having a functional group reactive with polyphenylene oxide may be a rubber, a thermoplastic resin, or a mixture thereof.
As a method of introducing such a functional group into a rubber, it is not limited especially and can be carry out by the well-known methods. For exam

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