JP3009407B2 - Flame retardant polyester composition - Google Patents

Description

The present invention relates to a flame-retardant polyester composition having significantly improved electrical properties such as moldability, mechanical properties, and tracking resistance and heat resistance in a wide temperature range. It is about.

<Prior Art> Aromatic polyesters typified by polyethylene terephthalate and polybutylene terephthalate are widely used in electric / electronic parts, mechanical mechanism parts, automobile parts, and the like, utilizing their excellent properties. Among them,
In particular, applications utilizing the electrical properties of these aromatic polyesters are expected to increase further with the development of the electronics industry.

By the way, when using resin materials for electrical and electronic components, it is necessary to satisfy the flame retardancy specified in UL standards, and in the field of electronic connectors, etc. In this case, it is required that the molded article has good mechanical properties and that the flame retardant does not bleed out to the surface of the molded article, and that the molded article does not generate gas that causes insulation failure.

As a flame retardant for an aromatic polyester corresponding to such various requirements, a brominated polycarbonate or a brominated epoxy having a relatively high molecular weight is used instead of a low molecular weight organic bromine compound such as decabromodiphenyl ether. It is becoming the subject.

However, although these oligomer type flame retardants do not bleed out, for example, brominated polycarbonate causes a transesterification reaction with an aromatic polyester,
There are problems such as lowering the mechanical properties of aromatic polyester, large decrease in viscosity during molding, and easy generation of electrically insulating gas during heat treatment of molded products. Due to the presence of the epoxy group, there is a problem that the viscosity increases during the stagnation of the molding and the fluidity becomes poor, and a gas that leads to a contact failure during the molding is easily generated.

Therefore, various attempts have been made to solve these problems by increasing the molecular weight of the flame retardant. For example, JP-A-54-83053 discloses a method using a high-polymerization degree brominated polycarbonate. JP-A-58-118849 discloses a method using a brominated epoxy compound having a high degree of polymerization.

<Problems to be Solved by the Invention> However, although the above-described method of increasing the degree of polymerization of the flame retardant has an effect of slightly lowering the gas, it is not at a satisfactory level and has an electrical property such as tracking resistance. However, there is a problem that is easily reduced.

Therefore, an object of the present invention is to solve the problems of the above-described conventional flame-retardant polyester composition.

<Means for Solving the Problems> The inventors of the present invention have conducted intensive studies to solve the above problems, and as a result, an aromatic bromine having an organic bromine compound having a specific molecular weight, an antimony compound, and fine particles of calcium carbonate having a specific particle size. The inclusion of a specific amount not only satisfies the flame retardancy, mechanical properties and non-blooming properties of the flame retardant, but also reduces the amount of gas generated during molding and from molded products, and improves tracking resistance and arc resistance. The present inventors have found that a polyester composition having excellent electrical properties, good moldability such as molding retention stability, and good heat resistance can be obtained, and arrived at the present invention. In addition, it was also found that the use of a specific hindered phenol compound and / or an inorganic tin compound improves the fluidity during molding and further reduces the amount of gas generated.

That is, the present invention relates to (A) an aromatic polyester 100
(B) 1 to 60 parts by weight of an organic bromine compound having an average molecular weight of 3,000 or more, and (C) 1 to 50 parts by weight,
It is intended to provide a flame-retardant polyester composition containing 0.01 to 5 parts by weight of (D) 0.01 to 5 parts by weight of fine particle calcium carbonate having an average particle diameter of 1.0 μm or less.

The aromatic polyester resin (A) used in the present invention is a polyester having an aromatic ring in a chain unit of a polymer,
Specifically, a polymer obtained by a condensation reaction containing an aromatic dicarboxylic acid (or an ester-forming derivative thereof) and a diol (or an ester-forming derivative thereof) as main components is a copolymer.

As the aromatic dicarboxylic acid referred to here, terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid 3,3'-biphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 4,4'-diphenylmethanedicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, 4,4'-diphenylisopropylidenedicarboxylic acid, 1 2,2-bis (phenoxy) ethane-4,4'-dicarboxylic acid, 2,5-anthracenedicarboxylic acid, 2,6-anthracenedicarboxylic acid, 4,4'-p-terphenylenedicarboxylic acid and 2,5-pyridine Examples thereof include dicarboxylic acids, and among them, terephthalic acid can be preferably used.

These aromatic dicarboxylic acids may be used as a mixture of two or more kinds. If the amount is small, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid and dodecandioic acid may be used together with these aromatic dicarboxylic acids. One or more kinds of acids and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid can be used in combination.

Further, as the diol component, ethylene glycol, propylene glycol, neopentyl glycol, 2-methyl-1,3-propanediol, aliphatic diols such as diethylene glycol and triethylene glycol,
Examples thereof include alicyclic diols such as 1,4-cyclohexanedimethanol and 1,3-cyclohexanedimethanol, and mixtures thereof. If the amount is small, the molecular weight
One or more kinds of 400 to 6,000 long-chain diols, that is, polyethylene glycol, poly-1,3-propylene glycol, polytetramethyl glycol, and the like may be copolymerized.

Specific examples of the aromatic polyester resin (A) include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyhexylene terephthalate, poly-1,4-cyclohexane dimethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate and polyethylene-1 Copolymerized polyesters such as polyethylene isophthalate / retephthalate, polybutylene terephthalate / isophthalate and polybutylene terephthalate / decane dicarboxylate, in addition to 2,2-bis (phenoxy) ethane-4,4'-dicarboxylate Is mentioned. Among these, polybutylene terephthalate, polyethylene terephthalate and poly-1,4-cyclohexane dimethylene terephthalate, which have well-balanced mechanical properties and moldability, can be particularly preferably used.

The aromatic polyester resin (A) used in the present invention preferably has a relative viscosity of 1.15 to 2.0, particularly 1.3 to 1.85, when a 0.5% o-chlorophenol solution is measured at 250 ° C.

In the present invention, the organic bromine compound having an average molecular weight of 3,000 or more used as the component (B) has a bromine atom in the molecule, has an average molecular weight of 3,000 or more, preferably 5,000 or more, and particularly has a bromine content of 30% by weight. The above are preferred. Specifically, a brominated polycarbonate (for example, a polycarbonate oligomer produced using brominated bisphenol A as a raw material), a brominated epoxy or a brominated phenoxy compound (for example, a reaction between a brominated bisphenol and epichlorohydrin or a brominated epoxy compound and a brominated bisphenol) Compound, brominated epoxy oligomer, brominated epoxy polymer, brominated phenoxy polymer), poly (brominated benzyl acrylate), brominated polyphenylene ether, brominated bisphenol A / cyanuric chloride / brominated phenol And halogenated polymers and oligomers such as brominated polyethylene (linear type and cross-linked type) and mixtures thereof, and those having an average molecular weight of 3,000 or more. Among them, brominated epoxy oligomers and polymers, brominated polystyrene, brominated polyphenylene ether, brominated polycarbonate and cyanuric chloride /
Preferred is a polycondensate of brominated bisphenol / brominated phenol, particularly brominated polycarbonate or a bisphenol A polycarbonate obtained from tetrabromobisphenol A capped with a monovalent phenol such as p-tert-butylphenol or tribromophenol. And a brominated phenoxy resin can be preferably used.

The amount of the organic bromine compound (B) having a molecular weight of 3,000 or more is 1 per 100 weight of the aromatic polyester (A).
6060 parts by weight, preferably 5-30 parts by weight. If the addition amount is less than 1 part by weight, the flame retardancy is not sufficient, and if it exceeds 60 parts by weight, the substance of the composition is undesirably reduced.

The (C) antimony compound used in the present invention is synergistically improved in flame retardancy by being added in combination with (B) an organic bromine compound having an average molecular weight of 3,000 or more, and (D) is also used in combination with fine particle calcium carbonate. Accordingly, an effect of greatly reducing the amount of generated gas is exerted.

Various antimony compounds can be used. Specifically, antimony oxide such as antimony trioxide and antimony pentoxide, antimony phosphate, sodium antimonate, Ksb (OH) ₆ , potassium antimonyl tartrate, Sb (OCH ₂ CH ₃ ) ₃ , Sb [OCH (CH ₃ ) CH ₂ CH ₃ ] ₃ and triphenylstibine, among which antimony oxide can be preferably used.

The amount of the antimony compound (C) used in the present invention is 1 to 50 parts by weight, preferably 3 to 30 parts by weight, based on 100 parts by weight of the aromatic polyester (A). The effect of improving the flame retardancy is not sufficient, and if it exceeds 50 parts by weight, the mechanical properties of the aromatic polyester are impaired. It is more preferable to add the antimony compound at a ratio of 1 antimony atom to 2 to 5 bromine atoms in the added flame retardant.

As the fine particle calcium carbonate (D) having an average particle diameter of 1.0 μm or less used in the present invention, various crystal forms can be used. In general, calcite crystals are used, but aragonite crystals and paterite crystals and mixtures thereof can also be used.

The production method is not particularly limited. And a soluble chloride method (calcium chloride-soda method). In particular, in the case of the synthesis method, it is advantageous that various particle sizes can be obtained by controlling the reaction conditions at the time of production.

The average particle size of the finely divided calcium carbonate needs to be 1.0 μm or less, preferably 0.5 μm or less, more preferably 0.3 μm or less. In addition, calcium carbonate has a specific surface area measured by the BET method of at least 10 m ² / g, more preferably at least 20 m ² / g, and particularly preferably at least 30 m ² / g. . Further, it is desirable for calcium carbonate to have an iron oxide content of 0.2% or less, preferably 0.1% or less, from the viewpoint of reducing the amount of generated gas and improving electrical characteristics.

The addition amount of the fine particle calcium carbonate (D) is 0.01 to 5 parts by weight, preferably 100 parts by weight of the aromatic polyester.
It is 0.05 to 5 parts by weight, more preferably 0.1 to 3 parts by weight.

If the amount is less than 0.01 part by weight, the effect of lowering gas and improve the electrical properties is small, while if it exceeds 5 parts by weight, the mechanical properties tend to decrease, which is not preferable.

Although not particularly essential in the present invention, (E) a molecular weight of 50
By further adding 0 or more hindered phenol compounds and / or inorganic tin compounds, it is possible to further reduce the amount of generated gas and improve the electrical characteristics.

The (E) hindered phenol compound having a molecular weight of 500 or more used in the present invention is represented by the following general formula (I) (Wherein, R ¹ is an alkyl group having 1 to 10 carbon atoms such as methyl, ethyl, propyl, tertiary butyl, etc.).
Of the above compounds, those having a molecular weight of 500 to 5,000 are preferred, and those having a molecular weight of 600 to 2,000 are particularly preferred. Specifically, tris (β- (3,5-di-t-butyl-4-hydroxy-phenyl) propionyl-oxyethyl) isocyanurate, 2,4-di-t-butyl-phenyl-3,5-di-
t-butyl-4-hydroxybenzoate, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butyl-
Phenyl) butane, 2,2'-methylene-bis (4-methyl-6-butyl-phenol), 1,3,5-tris (3 ',
5-di-t-butyl-4-hydroxybenzoyl) isocyanurate, tetrakis (methylene-3 (3,5-di-
t-butyl-4-hydroxy-phenyl) propionate) methane, 2,2-thio- (dimethyl-bis-3 (3,5-
Di-tert-butyl-4-hydroxyphenol) propionate), n-octadecyl-3- (4'-hydroxy-3 ', 5-di-tert-butylphenol) propionate, N, N'-hexamethylene-bis (3 , 5-di-tert-butyl-4-hydroxy-hydrocinamide), bis (3,5
-Di-t-butyl-4-hydroxybenzoylphosphonic acid) nickel salt of monomethyl ester, 1,3,
5-tri-methyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxy-benzyl) benzene and compounds of the following structure And tetrakis (methylene-3).
(3,5-di-t-butyl-4-hydroxy-phenyl)
Propionate) methane and 1,3,5-tri-methyl-
2,4,6-tris- (3,5-di-t-butyl-4-hydroxy-benzyl) benzene and the like can be preferably used. These may be used alone or in the form of an ester.

The amount of the hindered phenol compound (E) having a molecular weight of 500 or more is 0.005 to 5 parts by weight, preferably 1005 parts by weight, per 100 parts by weight of the aromatic polyester (A).
It is 0.01 to 3 parts by weight.

In the present invention, the inorganic tin compound used as the component (E) is at least one selected from tin oxide, stannic acid, metastannic acid and metal salts thereof.

Tin oxides include tin oxide (SnO) and tin dioxide (S
nO ₂ ), tin trioxide (Sn ₂ O ₃ ) and tin tetroxide (Sn
₃ O ₄ ).

Stannic acid is a hydrate of tetravalent tin oxide, and both α-stannic acid and β-stannic acid can be used. Metastannic acid is also a hydrate of tetravalent tin oxide. Examples of these production methods include a method in which dilute acid is applied to an aqueous solution of alkali stannate for α-stannic acid, and a method in which concentrated nitric acid is applied to tin oxide for β-stannic acid and metastannic acid. Further, examples of metal salts of stannic acid and metastannic acid include alkali metal salts such as potassium and sodium, alkaline earth metal salts such as magnesium, calcium and strontium, zinc salts, cobalt salts and lead salts.

Among these tin compounds, tin oxide, stannic acid and metastannic acid are preferable, and metastannic acid is particularly preferable.

(E) When a hindered phenol compound having a molecular weight of 500 or more and / or an inorganic tin compound is added, the addition amount is 0.005 to 5 parts by weight, preferably 1005 parts by weight, based on 100 parts by weight of the aromatic polyester. 0.
01 to 3 parts by weight, more preferably 0.02 to 2 parts by weight.

In the present invention, it is also preferable to add one or more phosphorus compounds selected from phosphoric acid, phosphorous acid and esters thereof in combination, since the amount of generated gas can be further reduced.

Such phosphorus compounds include phosphoric acid, dimethyl phosphate, trimethyl phosphate, trimethyl phosphate,
Methyl diethyl phosphate, triethyl phosphate, triisopropyl phosphate, tributyl phosphate, triphenyl phosphate, tribenzyl phosphate, tricyclohexyl phosphate,
Phosphorous acid, trimethyl phosphite, triethyl phosphite,
Tributyl phosphite, tri (hydroxybutyl) phosphite, triphenyl phosphite, bis (2,4-di-t-butylphenyl) pentaerythritol-diphosphite, bis (2,6-di-t- (Butyl-4-methylphenyl) pentaerythritol-diphosphite and tris (2,4-di-t-butylphenyl) phosphite. Of these, trimethyl phosphate and triphenyl phosphate are preferably used. Not only one kind of these phosphorus compounds but also two or more kinds can be used.

When one or more phosphorus compounds selected from the above-mentioned phosphoric acid, phosphorous acid and esters thereof are added, the addition amount is 0.01 to 5 parts by weight, preferably 0.01 to 1 part by weight, per 100 parts by weight of the aromatic polyester. Parts by weight.

In addition, although not particularly essential, when a fibrous and / or granular filler is further added to the composition of the present invention, the rigidity can be greatly improved without lowering other properties. Such fillers include glass fiber, carbon fiber, metal fiber, aramid fiber, ceramic fiber, asbestos, potassium whisker, titanite, gypsum fiber, sepiolite, glass beads, crow flake, talc, mica, clay, and sulfuric acid. Examples thereof include barium, tyran oxide, and aluminum oxide, and among them, chopped strand type glass fibers can be preferably used. The amount of these additives is usually 100
It is 3 to 80 parts by weight based on parts by weight.

Further, the composition of the present invention is an antioxidant, a heat stabilizer, an ultraviolet absorber, a lubricant, as long as the object of the present invention is not impaired.
One or more conventional additives such as a colorant such as a release agent, a dye and a pigment, and a nucleating agent can be contained. Also, a small amount of other thermoplastic resin (for example, polycarbonate, polyamide, polypropylene, polyethylene, ethylene / propylene copolymer, ethylene / butene-1 copolymer, ethylene / propylene / non-conjugated diene copolymer, ethylene / ethyl acrylate) Copolymer, ethylene / glycidyl methacrylate copolymer, ethylene / vinyl acetate / glycidyl methacrylate copolymer and ethylene / propylene-g-
A maleic anhydride copolymer).

Although the method for producing the composition of the present invention is not particularly limited, (A) aromatic polyester, (B) average molecular weight
More than 3,000 organic bromine compounds, (C) antimony compounds, and (D) fine particle calcium carbonate having an average particle diameter of 1.0 μm or less, and if necessary, specific hindered phenol compounds, inorganic tin compounds, phosphorus compounds, glass fibers, etc. A method in which other additives are melt-kneaded using an extruder is preferably exemplified.

The composition of the present invention can be easily molded by various molding methods such as injection molding, extrusion molding and blow molding.

<Examples> The effects of the present invention will be described in more detail below with reference to examples. All parts and percentages described below are based on weight.

Examples 1 to 7, Comparative Examples 1 to 6 100 parts of polybutylene terephthalate having a relative viscosity of 1.64, 8 parts of antimony trioxide, the following organic bromine compound and calcium carbonate were mixed in a Hensyl mixer in the amounts shown in Table 1. The mixture was melt-kneaded and pelletized at 250 ° C. using a vented 40 mmφ extruder. 130 ° C × 4
After drying for a period of time, heat treatment was performed at 280 ° C. for 30 minutes in a perfect oven to determine the amount of volatile components.

Also, using a 5 oz. Screw in-line type injection molding machine set at 250 ° C., molding at a mold temperature of 80 ° C. and a molding cycle (injection time / cooling time) (a) 10 seconds / 15 seconds.
STM No. 1 dumbbell, 3mmt x 80mmφ disk, 1/8 "t Izod impact test specimen and combustion test specimen (1/16" x 1/2 "x
At this time, the minimum molding pressure (gauge pressure), which is the minimum pressure necessary for completely filling the mold, was determined at the time of ASTM No. 1 dumbbell molding, and the molding cycle (b) was 10 seconds.
The molding lower limit pressure at / 60 seconds was also determined.

These specimens were subjected to a vertical combustion test in accordance with the UL-94 standard, and a tensile test was performed on each of the test pieces heat-treated in an oven at 180 ° C. for 500 hours and an untreated test piece according to ASTM D635, and further, ASTM D256. A notched Izod impact test was performed according to the following. In addition, IEC Pabli using 3mmt x 80mmφ discs formed in the molding cycle (a)
Tracking resistance (comparison tracking index, CTI value) was measured according to cation12.

 The results are shown in Table 1.

<Flame retardant> B-1: B-2: p = 3 in the above general formula of B-1 B-3: B-4: s = 18 in the general formula of B-3 above B-5: <Calcium carbonate> As is clear from the results in Table 1, the composition of the present invention using the organic bromine compound, the antimony compound and the specific calcium carbonate of the present invention in combination with the specific molecular weight not only has excellent retention stability and low gas property at the time of molding, but also has excellent properties. The obtained molded article has good heat resistance and can give a resin molded article with significantly improved electrical properties, especially tracking resistance.

Examples 8 to 15 and Comparative Examples 7 to 100 100 parts by weight of polybutylene terephthalate having a relative viscosity of 1.43, chopped strand type glass fiber (diameter 13 μm)
m, length 3 mm) 50 parts by weight, antimony trioxide 8 parts by weight,
For the organic bromine compound and calcium carbonate,
Except for using the amount of an additive appropriately selected from a tin compound, a hindered phenol compound and a phosphorus compound in the amount shown in Table 2, the same method as in Example 1 was used for blending, extrusion, molding and evaluation.

 Table 2 shows the results.

<Hindered phenol compound> E-1: tetrakis (methylene-3- (3,5-di-tert-butyl-4-hydroxy-phenyl) propionate) methane <tin compound> E-2: metastannic acid <phosphorus compound> E-3: Trimethyl phosphate As is clear from the results in Table 2, it can be seen that the composition of the present invention is excellent in flame retardancy, moldability, mechanical properties and electrical properties even when glass fibers are blended. Furthermore, when a specific hindered phenol compound, tin compound, phosphorus compound, and the like are added in combination, a synergistic improvement in gas generation, heat resistance, and the like can be obtained.

<Effect of the Invention> The flame-retardant polyester composition of the present invention, which comprises an aromatic polyester and a specific ratio of an organic bromine compound, an antimony compound, and fine-particle calcium carbonate having a specific molecular weight, has excellent moldability and mechanical properties. Because of its excellent properties, electrical properties and heat resistance, it is suitable for applications such as electric / electronic device parts and automobile parts.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-51-46344 (JP, A) JP-A-53-128656 (JP, A) JP-A-59-149954 (JP, A) JP-A-63-1988 51449 (JP, A)

Claims (3)

(57) [Claims] 1. An organic bromine compound (B) having an average molecular weight of 3,000 or more based on 100 parts by weight of an aromatic polyester (A).
A flame-retardant polyester composition containing 60 parts by weight, (C) 1 to 50 parts by weight of an antimony compound, and (D) 0.01 to 5 parts by weight of fine particle calcium carbonate having an average particle diameter of 1.0 μm or less. (D) Fine particle calcium carbonate having an average particle diameter of 1.0 μm or less, a specific surface area of 10 m ² / g or more measured by a BET method, and an iron oxide content of 0.2% or less. The flame-retardant polyester composition according to claim 1, which is calcium carbonate. (3) 100 parts by weight of the aromatic polyester (A), together with the components (B) to (D), and (E)
A hindered phenol compound having a molecular weight of 500 or more and / or
The flame-retardant polyester composition according to claim 1 or 2, further comprising 0.005 to 5 parts by weight of an inorganic tin compound.