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
1999-05-18
2001-04-24
Woodward, Ana (Department: 1711)
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...
C525S409000, C525S411000, C525S412000
Reexamination Certificate
active
06221947
ABSTRACT:
FIELD OF THE TECHNOLOGY
The present invention relates to a reinforced and flame-retarded thermoplastic resin composition. More specifically, it relates to a thermoplastic resin composition having excellent heat resistance, mechanical properties, flame retardancy and electric properties and to a production process therefor.
BACKGROUND
Thermoplastic resins are used for a variety of purposes due to excellent moldability thereof. Of the thermoplastic resins, use of engineering plastics in auto parts, structural parts, electric and electronic parts has been expanding making use of heat resistance thereof. In the field of electric and electronic parts, while efforts are being made to reduce weight, thickness and size and improve performance, safety at the time of use, productivity, use of reclaimed resources and the like are desired. Therefore, the application of thermoplastic resins, mainly polyester resins which have excellent heat resistance, moldability and chemical resistance and are easy to be flame-retarded, has been growing more than thermosetting resins.
When these thermoplastic resins are used in electric and electronic parts, they are generally reinforced with fibrous reinforcements and flame-retarded with halogen-based flame retardants typified by bromine-based flame retardants in order to improve the strength and safety of products comprising such parts.
Although thermoplastic resins themselves have high tracking resistance, one of the measures of electric insulating properties, the tracking resistance of the thermoplastic resins greatly lowers when they are reinforced and flame-retarded, whereby the risk of a fire rises despite the acquired flame-retardancy.
Many attempts have been made to improve the tracking resistance of the thermoplastic resins. For instance, blending of a metal oxide, metal silicate compound or the like with the thermoplastic resins has been proposed. This, however, has resulted in a reduction in mechanical properties in many cases.
Under such circumstances, a thermoplastic resin having excellent mechanical properties, flame retardancy and tracking resistance has been strongly desired.
Mitsubishi Electric Technical Report Vol. 69, No. 4 (1995) reports at pages 40 to 43 that when an overcurrent tripping test was made on reinforced resin compositions prepared by compounding aluminum borate whiskers, aluminum silicate fibers, E glass fibers, wollastonite, illite, mica or potassium titanate whiskers with nylon 46, aluminum borate whiskers, aluminum silicate fibers and wollastonite cut off a current more frequently than glass fibers, which are generally used as an inorganic reinforcement for resins, whereas potassium titanate whiskers and mica cut off a current less frequently than the glass fibers. The above report discloses no resin compositions comprising both a flame retardant and a reinforcement.
JP-B 6-4765 discloses a resin composition prepared by compounding aluminum borate whiskers with a resin (excluding a polyvinyl chloride resin). This publication discloses a flame retardant as one of additives that may be added to the resin composition as required. However, it shows no specific examples of the flame retardant or problems accompanied with the use of a flame retardant.
DISCLOSURE OF THE INVENTION
It is an object of the present invention to provide a thermoplastic resin composition having excellent mechanical properties, flame retardancy and tracking resistance.
It is another object of the present invention to provide a flame-retarded thermoplastic resin composition that is reinforced with aluminum borate whiskers and that can fully exhibit the above properties, unlike thermoplastic resin compositions reinforced with other whiskers.
It is still another object of the present invention to provide a novel use of aluminum borate whiskers.
It is a further object of the present invention to provide a process for improving the tracking resistance of the above thermoplastic resin composition of the present invention.
Other objects and advantages of the present invention will become apparent from the following description.
According to the present invention, the above objects and advantages of the present invention are attained by a thermoplastic resin composition that comprises (A) 100 parts by weight of a thermoplastic resin, (B) 5 to 80 parts by weight of a halogen-based flame retardant and (C) 5 to 200 parts by weight of aluminum borate whiskers.
The present invention will be described in detail hereunder.
Illustrative examples of the thermoplastic resin as the component (A) used in the present invention include general-purpose plastics such as polyethylene, polypropylene, ABS and polystyrene; engineering plastics such as aromatic polyesters, aromatic polycarbonates (may be abbreviated as PC hereinafter), polyamides, polyoxymethylene and modified polyphenylene ethers; super engineering plastics such as aromatic polyamides, PPS and liquid crystal polymers; and the like.
Aromatic polyesters, aromatic polycarbonates and polyamides are preferred from the viewpoint of adaptability to electric and electronic parts having heat resistance and heat aging resistance, and aromatic polyesters and aromatic polycarbonates are particularly preferred from the viewpoint of balance among properties, moldability and economy. Of the aromatic polyesters, polybutylene terephthalate (may be abbreviated as PBT hereinafter) is particularly preferred.
The component (A) may be one or a mixture of the above thermoplastic resins, or a copolymer obtained by copolymerizing part of a thermoplastic resin with another copolymerizable component. In the case of a copolymer, the proportion of the copolymerizable component is preferably 40 mol% or less.
The degree of polymerization of the thermoplastic resin as the component (A) is selected from a range that does not greatly impair mechanical properties and flowability at the time of molding. For example, a thermoplastic polyester preferably has an intrinsic viscosity, measured in o-chlorophenol at 35° C., of 0.5 to 1.5, particularly preferably 0.6 to 1.2. An aromatic polycarbonate preferably has a molecular weight of 15,000 or more, particularly preferably 18,000 to 30,000.
Any known processes may be used for producing the thermoplastic resin as the component (A). For example, aromatic polyesters may be produced by a general production process, exemplified by a process using a melt-polycondensation reaction or a process using a melt-polycondensation reaction and a solid-phase polycondensation reaction in combination.
Describing a process for producing polybutylene terephthalate, for example, polybutylene terephthalate can be produced by having terephthalic acid or an ester-forming derivative thereof (for example, a lower alkyl ester such as a dimethyl ester or monomethyl ester) reacted with tetramethylene glycol or an ester-forming derivative thereof by heating in the presence of a catalyst and polymerizing the obtained glycol ester of terephthalic acid to a predetermined degree of polymerization in the presence of a catalyst.
The most typical aromatic polycarbonate using bisphenol A as a divalent phenol can be produced by a process comprising the steps of adding gaseous or liquid phosgene to a mixed solution of an alkali aqueous solution of bisphenol A and methylene chloride and subjecting the mixture to polymerization in the presence or absence of a catalyst, or a process comprising the steps of subjecting bisphenol A and diphenyl carbonate to an ester interchange reaction while a phenol by-produced in the presence of an ester interchange catalyst is removed.
The halogen-based flame retardant as the component (B) used in the present invention is generally used as a flame retardant. The halogen is preferably bromine or chlorine.
Typical examples of the halogenated compound include brominated polystyrene, crosslinked brominated polystyrene, brominated polyphenylene ethers, brominated bisphenol A-type epoxy resins and/or modified products thereof obtained by blocking part or all of terminal glycidyl groups of the resins, brominated a
Sughrue Mion Zinn Macpeak & Seas, PLLC
Teijin Limited
Woodward Ana
LandOfFree
Reinforced and flame-retarded thermoplastic resin... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Reinforced and flame-retarded thermoplastic resin..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Reinforced and flame-retarded thermoplastic resin... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2555466