CS227538B1 - Self-extinguishing material for light-current engineering - Google Patents

Description

The invention relates to a polyphenylene oxide-based flame retardant material in admixture with other polymers and with the addition of stabilizers, flame retardants, optionally pigments, lubricants and other additives. The material is suitable for low-voltage electrical engineering.

Pure poly (2,6-dimethyl-1,4-phenylene oxide) is characterized by excellent electrical properties over a wide range of temperatures and frequencies, very good dimensional stability, considerable heat resistance and good mechanical strength, which together with excellent resistance to moisture and some chemical agents such as acids, bases and alcohols make it ideal for use in the electrical industry. However, due to the high melt viscosity and thus difficult processability, the use of pure polyphenylene oxide is very limited. Technically, this problem can be solved by mixing polyphenylene oxide with other polymers. For this, clear or tough polystyrene is most often used in combination with a smaller amount of rubbers and polyolefins. Such mixtures then have very good flow and mechanical properties, but the addition of other polymers reduces thermooxidation stability and degrades the original excellent electrical properties. Polystyrene in the mixture also increases the flammability of the material. For most technical applications this means adding flame retardants in addition to the stabilizers, which further significantly deteriorates the electrical properties, in particular the loss factor.

According to CS 201 766, the addition of substituted guanidines or biguanidines, which suppress unwanted changes in polyphenylene oxide during heat treatment, can significantly improve the electrical properties of the stabilized mixtures. However, at a typical content of about 50% by weight of the modification polymers, these are not flame retardant.

It has now been found that good flame retardancy of said compositions while maintaining excellent electrical properties

227 538 of the material can be achieved by the addition of guanidine or biguanidine derivatives in combination with β-ester amides of orthophosphoric acid.

The present invention provides a flame retardant material suitable for low current polyphenylene oxide based electrical engineering in admixture with other polymers, stabilizers and orthophosphoric ester amide as a flame retardant and optionally other additives such as pigments or lubricants, characterized in that the material comprises:

1.

0.05 to 3.0 parts by weight of guanidine derivatives of formula 1:

or biguanidine of formula II:

Where R @ 1 to R @ 2 is hydrogen, alkyl - C1-4 alkyl, R @ 1 and R @ 2 may also be hydrogen or C1-4 alkyl or aryl or aralkyl, for example phenyl, tolyl, xylyl - or benzyl2.

up to 15 parts by weight of an orthophosphoric acid ester amide of formula III:

(ABN) _n PO (00) _{3 -n} wherein A is hydrogen or Β, B is alkyl of 4 to 6 carbon atoms or phenyl, optionally (ABN) is morpholino, D is aryl as phenyl,

2,6 dimethylphenyl, 2- or 4-methylphenyl, n is 1 or 2.

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Polyphenylene oxide is understood to be poly (2,6-dimethyl-1,4-phenylone oxide). The other component of the blend may be any of the following polymers or combinations thereof: styrene plastic, for example clear polystyrene, tough polystyrene or terpolymor acrylonitrile, butadiene and styrene, polyolefins such as polyethylene, polypropylene, ethylene-propylene copolymer (thermoplastic or elastomeric) polyisobutylene, furthermore ethylene-propylenediene rubber or butyl rubber. The total content of these polymers may vary from 1 to 70% by weight, based on their mixture with the polyphenylene oxide. The material further contains thermo-oxidizing stabilizers (for example according to CS 175 876, or other phosphorous acid esters), additives for improving atmospheric aging resistance, optionally also pigments, lubricants and the like.

Mixtures of this type exhibit lower flammability and substantially better electrical properties at higher temperatures compared to materials prepared with the addition of other nitrogen bases and mixed orthophosphoric ester amide or a triaryl phosphate flame retardant compound (Example 1). Compared to a material with the addition of guanidines or biguanidines and a triaryl phosphate retarder, the above mixtures exhibit markedly better electrical properties and good flame retardancy (Example 2).

The following examples illustrate the invention. The parts given in the examples are by weight.

Example 1

To a mixture of 50 parts of poly (2,6-dimethyl-1,4-phenylene oxide), 43 parts of clear polystyrene, 7 parts of ethylene-propylene rubber, 2 parts of zinc oxide, 1 part of tris-4- (1-phenyl) -ethylphenyl ester of phosphorous acid as stabilizer was added for A and B: 0.5 parts of N, N-dimethylhexamethylenediamine, and for C: 0.5 parts of dimethylguanidine. Flame retardants were added to all mixtures in the case of A: 5 4M% nylphosphates, in cases B and C: 3 parts of orthophosphoric acid phenylether-bis (cyclo) hexyl] amide.

An identical batch of powdered poly (2,6-dimethyl-1,4-phenylene oxide), having a viscosity number of 57.3 ml / g (measured in chloroform at a concentration of 0.3 g / ml), was used to prepare these and other examples. 100 ml of the solution at 25 ° C).

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After thorough homogenization, the mixture was remelted on a laboratory screw extruder and the extruded string was granulated.

Plates were pressed from the granulate and test bodies were prepared by mechanical machining for determination of basic mechanical and thermal properties.

The measured values of the properties of the compared materials are given in Table I.

Example 2

To a mixture of 50 parts of poly (2,6-dimethyl-1,4-phenylene oxide), parts of tough polystyrene, 2 parts of polyethylene, 3 parts of titanium dioxide and a stabilizer consisting of: 1.2 parts of tris (nonylphenyl) phosphite and 0, 2 parts of 2,6-di-tert-butyl-4-methylphenol, 1.5 parts of phanyl-o-tolyl-xylylguanidine and flame retardants were added for A: 5 parts of isopropylphenyl-diphenyl phosphate, 12 parts of diphenyl ester morpholide for B orthophosphorus.

The material was processed and evaluated as in Example 1. The measurement results are summarized in Table IX.

Claims (2)

BEFORE THE INVENTION 227 538 Polyphenylene oxide based flame retardant electro-flammable electrical material in admixture with other orthophosphoric acid polymers, stabilizers and diesters or orthophosphoric ester diamides as flame retardants and optionally other additives such as pigments or lubricants, characterized in that it contains 0.05 to 3.0 parts by weight of guanidine derivatives of the general formula I or biguanidine. of formula II _n l r.4 R | R 1 5 N - R R ² 1 - N _K \ / R ³ c. N - C. .z x N - R ⁶ where R ³ to R ⁷ is hydrogen, C 1 -C 4 alkyl, R ¹ -R ² can also be hydrogen or C 1 -C 4 alkyl or aryl or aralkyl such as phenyl, tolyl-, xylyl- or benzyl-2 to 15 parts by weight of an orthophosphoric ester ester amide of formula III (ABN) _n PO (00) ₃ . _n wherein A is hydrogen or B, B is alkyl of 4 to 6 carbon atoms 4 θ or phenyl or (ABN) ^J morpholine, D is aryl as phenyl, 2,6 dimethylphenyl, 2- or 4-methylphenyl, n is 1 or 2.