Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1998-12-30
2002-08-13
Toomer, Cephia D. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S139000, C523S179000
Reexamination Certificate
active
06433045
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to a flame-retardant thermoplastic polyester resin composition having excellent flame-retarding properties even without any halogen flame retardant, and a process for producing it. In particular, the present invention relates to a flame-retardant resin composition having excellent flame-retarding properties, and also good mechanical properties and moldability, and an excellent heat residence stability or melt stability, and a process for producing it.
2. Prior Arts
Thermoplastic polyester resins having excellent characteristics are widely used as materials for parts of electric and electronic appliances and also parts of automobiles. Particularly in the fields of electric and electronic appliances, flame-retardancy is often imparted to them so as to insure the safety from a fire.
Usually a halogen flame-retardant is used for imparting the flame retardancy to the thermoplastic polyester resins. However, when the halogen flame-retardant is used, a halogen compound contained as an impurity therein or formed as a thermal decomposition product thereof may corrode a kneader, molding machine, mold, etc. in the kneading and molding steps. In addition, some of the halogen flame-retardants form a poisonous gas even in a very small amount when they are decomposed.
A method for~improving the flame retardancy by adding red phosphorus or a phosphoric acid compound to solve the above-described problem is known (see, for example, JP-A 55-82149 and JP-A 48-91147). However, the effect of improving the flame retardancy was yet insufficient even when such a flame retardant is used, and it was impossible to obtain V-0 rank in UL. A method for solving this problem by using a specified calcium or aluminum salt of phosphinic acid was proposed (JP-A 8-73720). However, even this compound has a problem that it must be added in a large amount for obtaining the excellent flame retardancy and, as a result, the moldability of the polyester is impaired.
SUMMARY OF THE INVENTION
After investigations made for the purpose of obtaining excellent flame retardancy and also mechanical properties and moldability of the thermoplastic polyester at a reasonable cost without using the halogen flame-retardant, the inventors have. found that an excellent flame-retardancy can be obtained by adding a small amount of a nitrogen compound. The present invention has been completed on the basis of this finding.
Namely, the present invention relates to a flame-retardant thermoplastic polyester resin composition comprising:
(A) 100 parts by weight of a thermoplastic polyester. resin compounded with:
(B) 5 to 40 parts by weight of a phosphinic acid salt represented by the formula (1) and/or a diphosphinic acid salt represented by the formula (2) and/or a polymer thereof, and
(C) 1 to 35 parts by weight of a nitrogen-containing, organic substance:
wherein R
1
and R
2
each represent a linear or branched C
1
to C
6
alkyl or phenyl group, R
3
represents a linear or branched C
1
to C
1
o alkylene, an arylene, an alkylarylene or an arylalkylene group, M represents a calcium ion or an aluminum; ion, m represents 2 or 3, n represents 1 or 3 and X represents l or 2.
In other words, the composition comprises (A), (B) and (C).
(B) is at least one of (1), (2) and a polymer thereof. It is preferable that the nitrogen-containing organic substance (C) is a nitrogen-containing condensate or a salt of an amino-having, nitrogen-containing compound and an acid.
DETAILED DESCRIPTION OF THE INVENTION
The detailed description will be made on the respective constituents of the resin composition of the present invention.
The thermoplastic polyester resin (A) which is the base resin of the present invention is a polyester obtained by the polycondensation of a dicarboxylic acid compound with a dihydroxy compound, polycondensation of a hydroxycarboxylic acid compound or polycondensation of these three compounds. The effect of the present invention can be obtained when the polyester is either a homopolyester or copolyester.
Examples of the dicarboxylic acid compounds constituting the thermoplastic polyester resin used herein include known dicarboxylic acid compounds such as terephthalic acid, isophthalic acid, naphthalene-dicarboxylic acid, diphenyldicarboxylic acid, diphenyl ether dicarboxylic acid, diphenylethanedicarboxylic acid, cyclohexanedicarboxylic acid, adipic acid and sebacic acid, as well as those substituted with an alkyl, alkoxy or halogen. These dicarboxylic acid compounds are usable also in the form of an ester-forming derivative thereof such as a lower alcohol ester, e.g. dimethyl ester, thereof.
Examples of the dihydroxy compounds constituting the polyester (A) of the present invention include dihydroxy compounds such as ethylene glycol, propylene glycol, butanediol, neopentyl glycol, hydroquinone, resorcinol, dihydroxyphenyl, naphthalenediol, dihydroxydiphenyl ether, cyclohexanediol, 2, 2-bis(4hydroxyphenyl) propane and diethoxylated bisphenol A; polyoxyalkylene glycols and those substituted with an alkyl, alkoxy or halogen. They are used singly or in the form of a mixture of two or more of them.
Examples of the hydroxycarboxylic acids include hydroxybenzoic acid, hydroxynaphthoic acid and hydroxycarboxylic acids such as diphenylenehydroxycarboxylic acids, as well as those substituted with an alkyl, alkoxy or halogen. Further, ester-forming derivatives of these compounds are also usable. One or more of these compounds are usable in the present invention.
The polyesters may have a branched or crosslinked structure formed by using a small amount of a trifunctional monomer such as trimellitic acid, trimesic acid, pyromellitic acid, pentaerythritol or trimethylolpropane.
Any of the thermoplastic polyesters formed by the polycondensation of the above-described compound as the monomer component is usable as the component (A) in the present invention. The monomer components are usable either singly or in the form of a mixture of two or more of them. The copolymers comprise, as the main component, preferably a polyalkylene terephthalate, still preferably a polybutylene terephthalate and/or polyethylene terephthalate.
In the present invention, the thermoplastic polyesters may be those modified by a known crosslinking method or graft polymerization method.
The thermoplastic polyesters usable in the present invention are those having an intrinsic viscosity of 0.5 to 1.3 dl/g. From the viewpoints of the moldability and mechanical properties, those having an intrinsic viscosity in the range of 0.65 to 1.1 dl/g are preferred. When the intrinsic viscosity is lower than 0.5 dl/g, the mechanical strength is extremely lowered and, on the contrary, when it is higher than 1.3 dl/g, the flowability of the resin is low to reduce the moldability.
The compounds used as the component (B) in the present invention include phosphinic acid salts of the formula (1) and/or diphosphinic acid salts of the formula (2) and/or polymers thereof:
wherein R
1
and R
2
each represent a linear or branched C
1
to C
6
alkyl or phenyl group, R
3
represents a linear or branched C
1
to C
10
alkylene, an arylene, an alkylarylene or an arylalkylene group, M represents a calcium ion or an aluminum ion, m represents 2 or 3, n represents 1 or 3, and X represents 1 or 2.
One or more of these compounds are used in the present invention.
In the present invention, 5 to 40 parts by weight of the compounds (B) can be added to 100 parts by weight of the thermoplastic polyester (A). When the amount of the compound (B) is below 5 parts by weight, the intended high flame-retardancy cannot be obtained and, on the contrary, when it is above 40 parts by weight, the mechanical properties are impaired and the material cost becomes too high and impractical. From the viewpoints of the cost and flame-retardancy, the amount is particularly preferably in the range of 7 to 35 parts by weight.
Examples of the nitrogen-containing organic compounds usable as the component (C) in the present invention include
Hanabusa Kazuhito
Matsushima Mitsunori
Nixon & Vanderhye P.C.
Polyplastics Co. Ltd.
Toomer Cephia D.
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