Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
1999-11-03
2001-06-12
Yoon, Tae H. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S463000, C523S201000, C523S206000
Reexamination Certificate
active
06245845
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to resin parts of electronic and electrical equipment, particularly resin parts of electronic and electrical equipment using a high frequency wave and to a fluorine-containing resin composition suitable as a molding material for the resin parts.
PRIOR ART
A lot of parts made of resins are used on electronic and electrical equipment. Some of molding materials for those resin parts are selected simply from the viewpoint of mold-processability. However as a result of making performance higher, down-sizing, high integration and high densification of electronic and electrical equipment, severe demands for precise processability, electronic and electrical characteristics, heat resistance, etc. have been increasing. Particularly with respect to information processing and communications equipment, a frequency band used therefor are transferring to a high frequency band. For example, for parts such as a printed circuit board, connector, insulating material (for example, an antenna built in a housing of portable phone, etc.), high frequency filter, high frequency antenna and microwave range, excellent electric insulating property and dielectric property in addition to precise processability, mechanical properties and thermal characteristics have been required. Among them with respect to dielectric property which is related to a dielectric loss in electronic and electrical equipment using a high frequency wave, a dielectric constant and dissipation factor are required to be as low as possible.
However with respect to general-purpose engineering plastics being excellent in moldability, there is a tendency that those having more excellent heat resistance are high in dielectric constant and dissipation factor.
As a result of down-sizing, high integration and high densification, enhancement of dimensional stability of resin parts has been demanded. To cope with such a demand, various fillers are added to the resin. However there is a case where the addition of the fillers lowers not only mold-processability but also dielectric property.
For example, JP-A-7-118529 discloses a resin composition for electronic parts which is prepared by using, as a matrix resin, a thermoplastic resin comprising polyetherimide, polyphenylene ether and aromatic vinyl resin and adding thereto 5 to 60% by weight of aluminum borate whisker or magnesium borate whisker. Also JP-A-8-59992 discloses a resin composition for high frequency electronic parts which is prepared by using, as a matrix resin, a thermoplastic resin comprising polyetherimide, polyphenylene ether and aromatic vinyl resin and adding thereto a silicate fiber such as wallastonite, xonotlite, mullite, zinc silicate, sepiolite or chrysotile.
Further JP-A-8-134263 discloses a resin composition for high frequency electronic parts which is prepared by using, as a matrix resin, a thermoplastic resin (excluding polyamide resin) or a thermosetting resin (excluding a phenolic resin) and adding thereto 5 to 60% by weight of a reinforcing fiber mainly comprising a fibrous substance of the specific metal silicate. That resin composition is suitable as a material for printed circuit boards for high frequency and has a low dielectric constant, low dissipation factor, high heat resistance, high mechanical strength and good heat conductivity.
However in the resin compositions disclosed in JP-A-7-118529 and JP-A-8-59992, since the matrix resin is prepared by combining amorphous resins, mold-processability thereof is poor and dipping in a soldering bath at a temperature exceeding 260° C. for a long period of time cannot be conducted, and in addition, heat resistance (deflection temperature under load or heat distortion temperature) of an obtained molded article is up to 210° C.
Also though JP-A-8-134263 suggests use of fluorine-containing meltable resin solely or combination use of fluorine-containing meltable resin with other resin as a matrix resin in a resin composition, it does not teach concretely not only components of the composition but also use of polytetrafluoroethylene (PTFE) (PTFE is a fluorine-containing resin which is not melt-processable) which is represented by a low molecular weight PTFE and is not fibrillated. Also with respect to an obtained molded article, when its dielectric constant is decreased to 3.5 or lower, its heat resistance (deflection temperature under load) is lowered and when its heat resistance is intended to be enhanced, its dielectric constant exceeds 3.5.
Thus molded articles having well-balanced enhanced characteristics such as dielectric property, heat resistance, mold-processability (precise processability) and mechanical properties have not been found out.
The present inventors have made intensive studies with respect to use of a fluorine-containing resin as a molding material for electronic and electrical parts which had been left unused since it is poor in melt-processability while its dielectric constant is low, and as a result, have found that a fluorine-containing resin composition comprising (I) a fluorine-containing resin mixture of (a) a fluorine-containing resin containing PTFE not to be fibrillated among PTFE which are not melt-processable and (b) a thermoplastic resin other than the fluorine-containing resin and (II) a specific whisker can unexpectedly have well-balanced enhanced characteristics such as dielectric property, heat resistance, mold-processability (precise processability) and mechanical properties. Thus the present invention has been completed.
SUMMARY OF THE INVENTION
Namely the present invention relates to the fluorine-containing resin composition for parts of electronic and electrical equipment which comprises 70 to 95% by weight of (I) fluorine-containing resin mixture comprising (a) a fluorine-containing resin containing PTFE not to be fibrillated and (b) a thermoplastic resin other than the fluorine-containing resin and 5 to 30% by weight of (II) a metal compound whisker having a single bond strength of not less than 190 KJ/mol calculated from a dissociation energy of bond between a metal element and oxygen.
Further the present invention relates to parts of electronic and electrical equipment which are molded articles comprising the thermoplastic resin (b) as a matrix resin and the fluorine-containing resin (a) and the whisker (II) being dispersed uniformly in the matrix resin, and a dielectric constant of the whole molded article is not more than 3.5, preferably not more than 3.0.
REFERENCES:
patent: 5506049 (1996-04-01), Swei et al.
patent: 5922453 (1999-07-01), Horn, III et al.
patent: 7-118529 (1995-05-01), None
patent: 8-59992 (1996-03-01), None
patent: 8-134263 (1996-05-01), None
Arase Takuya
Komori Masaji
Miyamori Tsuyoshi
Armstrong Westerman Hattori McLeland & Naughton LLP
Daikin Industries, Inc.
Yoon Tae H.
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