JPH0551519A - Flame-resistant polyester resin composition - Google Patents

Abstract

PURPOSE:To provide a flame-resistant resin compsn. capable of giving a molded product excellent in flame resistance and mechanical properties and free from generation of any toxic gas when brought into contact with a flame. CONSTITUTION:A polyester mainly having alkylene terephthalate units copolymerized with 0.5-30mol% organophosphorus compd. of chemical formula 1 is blended with a magnesium compd. having water of crystallization.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-resistant polyester resin composition which gives a molded article excellent in mechanical strength.

[0002]

2. Description of the Related Art Polyalkylene terephthalates such as polybutylene terephthalate (PBT) and polyethylene terephthalate (PET) have excellent mechanical and chemical properties and are widely used as general-purpose engineering plastics for molded products. There is.

By the way, in recent years, there has been an increasing demand for flame resistance of various plastic products from the viewpoint of fire prevention. Especially, since PBT and PET are used in large quantities for industrial purposes,
The establishment of countermeasures is urgently needed.

Conventionally, various attempts have been made to impart flame resistance to polyester, and there is a method of coexisting a halogen-based compound and an antimony compound in the polyester (for example, JP-A-61-185559). According to this method, the flame resistance and strength characteristics of the molded product reach a certain level, so this method is currently generally used. However, since a compound mainly containing a halogen is used, it has a fatal problem that a toxic gas is generated at the time of flame contact, and non-halogenation without a halogen compound is urgently needed.

As a non-halogenation method, there is a method of incorporating a phosphorus compound into polyester. For example, Japanese Patent Application Laid-Open No. 2-1730 proposes a method of copolymerizing the organic phosphorus compound represented by the above chemical formula 1. ing. However, the polyester obtained by this method is not filled with a filler,
So-called natural grade has very good flame resistance, but there is a problem that the flame resistance is not sufficient with a filler grade to which a filler such as glass fiber or talc is added.

[0006]

DISCLOSURE OF THE INVENTION The present invention is intended to provide a flame resistant polyester resin composition which does not generate a toxic gas during flame contact and gives a polyester molded article excellent in flame resistance and mechanical properties. is there.

[0007]

Means for Solving the Problems As a result of intensive studies for solving the above-mentioned problems, the present inventors have remarkably added a magnesium compound having water of crystallization to a polyester obtained by copolymerizing an organic phosphorus compound as described above. The inventors have found that the flame resistance is improved and have reached the present invention.

That is, the gist of the present invention is as follows. Polyester having an alkylene terephthalate unit as a main component and an organic phosphorus compound represented by the following structural formula 2 copolymerized with 0.5 to 30 mol% with respect to a diol component has a limiting viscosity of 0.5 or more and a magnesium compound having crystal water of 5
A flame resistant polyester resin composition containing 50% by weight.

[0009]

[Chemical 2]

(R is an alkylene group having 2 to 6 carbon atoms, Ar
Represents an aromatic group, and the aromatic ring may be substituted with a lower alkyl group. Further, m and n represent integers whose sum is 2 to 20. )

The present invention will be described in detail below. As the main component forming the polyester in the present invention,
Preferred are terephthalic acid as the dicarboxylic acid component, ethylene glycol and 1,4-butanediol as the diol component (all of which include ester-forming derivatives), but isophthalic acid, 5-sodium sulfoisophthalic acid, diethylene glycol, propylene glycol. ,
A small amount of 1,4-cyclohexanedimethanol, pentaerythritol, 4-hydroxybenzoic acid, adipic acid, trimellitic acid or the like may be used in combination as a copolymerization component.

Ar in the organic phosphorus compound is a trivalent aromatic group, and examples thereof include a benzene ring and a naphthalene ring. The aromatic ring may have a hydrocarbon group having 1 to 20 carbon atoms as a substituent. Organic phosphorus compounds are disclosed in JP-A-1
It can be obtained by the method described in JP-A-221386.

The organophosphorus compound may be used as it is for the synthesis of the copolyester, or may be used in the form of a monomer, oligomer or polymer reacted with an acid component such as terephthalic acid or isophthalic acid.

The copolymerization amount of the organic phosphorus compound is 0.5 to 30 mol%, preferably 3 to 10 mol% based on the diol component. When the amount of the organic phosphorus compound is less than 0.5 mol%, the flame resistance of the polyester is insufficient, and when it is more than 30 mol%, the mechanical properties of the obtained polyester are impaired.

The organophosphorus compound may be added when the polyester is produced by a conventional method. That is, when a polyester is produced from a dicarboxylic acid or dicarboxylic acid diester and a diol by an esterification or transesterification reaction and a polycondensation reaction, it is added at any stage from the esterification or transesterification reaction to the initial stage of the polycondensation reaction. be able to.

The polyester in the present invention is, for example,
It can be manufactured as follows. In the case of PBT, first, in the presence of a suitable catalyst, dimethyl terephthalate (DMT)
And 1,4-butanediol (BD) are transesterified with an organic phosphorus compound, and then in the presence of any known catalyst,
It can be obtained by polycondensation. On the other hand, PET
In the case of, first terephthalic acid (TPA) and ethylene glycol (EG) are esterified, and after the esterification reaction is completed,
That is, the esterification reaction rate is 90% or more, preferably 94%.
After reaching 96%, it can be obtained by adding a known arbitrary catalyst and an organic phosphorus compound and polycondensing.

The polycondensation reaction in the production of polyester is usually 225 to 2,000 in the case of PBT system under a reduced pressure of about 0.01 to 10 torr.
It is carried out at a temperature of 260 to 310 ° C. at a temperature of 260 to 310 ° C. in the case of a PET system at 260 ° C. until a desired degree of polymerization is obtained.

The polyester used in the present invention must have an intrinsic viscosity of 0.5 or more. The intrinsic viscosity
When it is less than 0.5, the mechanical strength of the obtained polyester molded product is remarkably lowered, which is not preferable.

The polyester may contain additives such as stabilizers such as hindered phenol compounds, cobalt compounds, fluorescent agents, color improving agents such as dyes and pigments such as titanium dioxide. ..

As the magnesium compound to be added to the polyester, a compound having water of crystallization is used, and oxides, sulfates and carbonates are preferably used. And, it is preferable to use a short fibrous material rather than a granular material because it is useful for reinforcing the mechanical strength, and in particular, the formula MgSO _4.5 MgO
The magnesium compound represented by 8H ₂ O is most suitable.

The content of the magnesium compound is 5 to 50% by weight, preferably 5 to 30% by weight, based on the total weight of the polyester resin composition. If the amount is less than this range, the effect of addition is not substantially expressed, and even if the amount of addition exceeds this range, not only the flame resistance improving effect becomes saturated, but also the strength characteristics of the polyester are impaired. , Not preferable.

Further, in the polyester resin composition of the present invention, the mechanical strength of the molded article can be further improved by incorporating glass fiber. As glass fiber,
Usually, chopped strands having a length of 2 to 5 mm are preferably used. The glass fiber content is 5 to 50% by weight, preferably 5 to 30%, based on the total weight of the polyester resin composition.
Weight percent is suitable. If the amount is less than this range, the effect of addition is not substantially exhibited, while if the amount exceeds the range, the mechanical strength is rather deteriorated.

The polyester resin composition of the present invention can be manufactured, for example, as follows. The dried phosphorus-containing flame-resistant polyester and magnesium compound (and glass fiber) are fed to the hopper of a uniaxial or biaxial compounder, or each component is separately fed to an independent hopper and melt-mixed by the compounder. After that, it is cooled and cut into chips.

To produce a molded product from the polyester resin composition of the present invention, the chips are dried and then the molding temperature is
Molding may be performed at 220 to 290 ° C and a mold temperature of 40 to 80 ° C.

[0025]

EXAMPLES Next, the present invention will be specifically described with reference to examples. The characteristic values of polyester in the examples were measured as follows. (1) Intrinsic viscosity [η] Using an equal weight mixture of phenol and ethane tetrachloride as a solvent, measurement was performed at a temperature of 20.0 ° C. (2) Flame resistance Judged according to UL 94 standard. (3) Bending strength Measured on a 1/8 inch thick test piece according to the ASTM D 790 standard. (4) Tensile strength Measured with a dumbbell No. 1 type test piece having a thickness of 1/8 inch according to ASTM D638 standard. The test pieces of each test were molded using a J-100-S type injection molding machine manufactured by Nippon Steel Co., Ltd. at a molding temperature of 230 ° C., a mold temperature of 40 ° C., and an injection pressure of 625 kg / cm ² .

Reference Example Diphenylphosphine oxide and p-benzoquinone were reacted in ethyl cellosolve at 125 ° C. for 2 hours to obtain diphenyl- (2,5-dihydroxyphenyl) phosphine oxide (PPQ). 0.1 mol of this PPQ and 0.3 mol of ethylene carbonate were placed in a glass flask, 0.01 mol of potassium carbonate as a catalyst and 0.5 mol of ethylene glycol diethyl ether as a solvent were added, and the mixture was reacted at 100 ° C. for 6 hours with stirring to give a white organic phosphorus compound. Crystal (PPQ-
E) got.

Examples 1 to 6 DMT, BD and PPQ-E were charged into a reactor so that the molar ratio was 95: 150: 5, and tetrabutyl titanate (T
BT) to the acid component of the polyester 3 × 10 ^-4
After adding a molar amount and performing the transesterification reaction,
Furthermore, 3 × 10 ⁻⁴ mol of TBT was added and polycondensation reaction was carried out to obtain a polyester having an intrinsic viscosity of 0.91. A magnesium compound represented by the formula MgSO ₄ .5MgO.8H ₂ O and glass fiber having a diameter of 150 μm and a length of 3 mm were added to the obtained polyester in a biaxial compounder PCM manufactured by Ikegai Iron Works Co., Ltd. in the amounts shown in Table 1. It was supplied, kneaded, and made into chips. A molded product (test piece) was molded using the obtained chips. The characteristic values of the molded product are shown in Table 1. No bubbles or silver streaks were found on the surface of the molded product, and the moldability was good.

Examples 7 to 8 The same tests as in Example 1 were conducted using polyesters produced in the same manner as in Example 1 while changing the addition amount of the organic phosphorus compound. The characteristic values of the obtained molded product are shown in Table 1.

Examples 9 to 10 TPA and EG are continuously supplied to a reactor in which bis- (β-hydroxyethyl terephthalate) and its low polymer (BHET) are present to cause an esterification reaction, and BHET is continuously added. I got it. PPQ-E (0.05 mol) and antimony trioxide (2 × 10 ^-4 mol) were added to 1 mol of the acid component constituting the polyester, and polycondensation was performed to obtain a polyester having an intrinsic viscosity of 0.69. Using this polyester, the same test as in Example 1 was conducted. The characteristic values of the obtained molded product are shown in Table 1.

Example 11 The same test as in Example 1 was conducted by changing the phosphorus compound to a compound (PPQ-P) synthesized by using propylene carbonate instead of ethylene carbonate in Reference Example. The characteristic values of the obtained molded product are shown in Table 1.

Comparative Example 1 The same test as in Example 1 was conducted by adding only glass fiber to the polyester of Example 1 in the amount shown in Table 1. The characteristic values of the obtained molded product are shown in Table 1.

Comparative Example 2 The same test as in Example 1 was conducted by adding only the glass fiber to the polyester of Example 9 in the amount shown in Table 1. The characteristic values of the obtained molded product are shown in Table 1.

[0033]

[Table 1]

[0034]

According to the present invention, there is provided a flame resistant polyester resin composition which does not generate a toxic gas during flame contact and gives a polyester molded article excellent in flame resistance and mechanical properties.

Claims (2)

[Claims] 1. An intrinsic viscosity of 0.5, which is mainly composed of an alkylene terephthalate unit and in which 0.5 to 30 mol% of an organic phosphorus compound represented by the following structural formula 1 is copolymerized with a diol component.
A flame-resistant polyester resin composition comprising the above polyester blended with 5 to 50% by weight of a magnesium compound having water of crystallization. [Chemical 1] (R represents an alkylene group having 2 to 6 carbon atoms, Ar represents an aromatic group, and the aromatic ring may be substituted with a lower alkyl group. M and n are integers whose sum is 2 to 20. Represents.) 2. The flame-resistant polyester resin composition according to claim 1, which contains 5 to 50% by weight of glass fiber.