CS201766B1 - Material for low-current electrical engineering based on polyphenylene oxide and its mixtures with other polymers - Google Patents

Abstract

The invention relates to a material for low-current electrical engineering with improved dissipation factor at higher temperatures, improved adhesion to metal foil and thermo-oxidative stability. The material, which is made of polyphenylene oxide and its mixtures with other polymers and optionally other additives, contains 0.1 to 5% by weight of guanidine or biguanidine derivatives.

Description

201 766 1

The invention relates to polyphenylene oxide and its mixtures and other polymers and additives of nitrogenous substances, the use of which is advantageous especially in low-current electrical engineering.

Six-pole (2,6-dimethyl-1,4-phenylene oxide) is characterized by excellent electrical properties in a wide range of frequencies and temperatures, very good dimensional stability, significant thermal insulation and good mechanical strength, which, together with excellent resistance to moisture, acids, alkalis and alcohols, predetermines it for use in the electrical industry. Its disadvantages include relatively low notch toughness, a significant tendency to crack, especially under mechanical stress, and high melt viscosity at processing temperatures.

The problem of difficult processing can be solved by adding clear or tough polystyrene, which, however, in addition to reducing the viscosity of the melt of the obtained mixture, also causes a decrease in the softening temperature. The presence of clear polystyrene also worsens the notch toughness and increases the tendency to crack, the excellent electrical properties of the material are preserved, only the upper limit of usability at higher temperatures is reduced depending on the polystyrene content. The most frequently used method of modification - the addition of tough polystyrene - causes a partial improvement in the notch toughness, but at the same time there is a significant deterioration in the electrical properties, especially the loss factor, the value of which increases sharply with increasing temperature. Such a material is not suitable for special applications in low-current electrical engineering.

A certain compromise between these two methods of modification can be achieved by mechanically mixing elastomers into polyphenylene oxide and its mixture with polystyrene according to the Czech Patent No. 165 110, which significantly improves the notch toughness and somewhat reduces the increase in the loss factor value with increasing temperature in comparison with mixtures containing only tough polystyrene. However, the properties of this material are not yet sufficient for special electrical engineering. In particular, the highly desirable use as a support for clad boards, from which printed circuit boards are prepared, is limited due to the insufficient adhesion of the metal foil and the resulting low peelability value. The deterioration of the loss factor value at higher temperatures does not allow the use of the material in a wider temperature range, especially at high frequencies.

It has now surprisingly been found that the said disadvantageous properties are not exhibited by polyphenylene oxide and its mixtures with other polymers, where, according to Czechoslovak author's certificate No. 185031, substituted guanidines or biguanidines are used as components in the mixture suppressing undesirable changes in the properties of polyphenylene oxide during heat treatment. The subject of the invention is a material for low-current electrical engineering based on polyphenylene oxide and its mixtures with other polymers and optionally other additives, such as stabilizers, pigments, lubricants and fillers, characterized in that it contains 0.1 to 5 parts by weight of guanidine (I) derivatives. 2 201 766

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N (I) or biguanidine x z

C-N-C

I R4 N-R5 N-R6 1 7 where R to R are hydrogen, methyl, ethyl, phenyl, tolyl or xylyl, based on 100 parts by weight of the polymer or their mixture in the material. The basic component of the mixture is polyphenylene oxide of the general formula

As a rule, polyphenylene oxide is understood to mean poly(2,6-dimethyl-1,4-phenylene oxide), which may, however, optionally contain poly(1,2-phenylene oxides).

Another component of the polyphenylene oxide mixture may be any of the following polymers, or a combination thereof! styrene plastic, for example clear polystyrene, tough polystyrene or a terpolymer of acrylonitrile, butadiene and styrene, polyolefins, for example polyethylene, polypropylene, ethylene-propylene copolymer (with properties of a thermoplastic or elastomer), polyisobutylene, and also ethylene-propylene-diene rubber, butyl rubber or polysiloxane. The total content of these modifying polymers may range from 0 to 50% by weight, calculated on the mixture with polyphenylene oxide. The material may also contain other commonly used additives, such as stabilizers, pigments, lubricants, fillers and the like. When using guanidine and biguanidine derivatives as modifying additives, a significant improvement in the loss factor value at higher temperatures, better adhesion of the metal foil to the surface of the material and excellent thermo-oxidative stability is achieved, while other properties remain without significant changes in comparison with polyphenylene oxide and its mixtures prepared with the addition of nitrogen bases according to Czechoslovak author's certificate No. 159032.

The invention will be illustrated by the following examples. The parts given in the examples are by weight. 201 766 3 Example 1 Either A: N,N'-dimethylhexa-methylenediamine (according to Czechoslovak Automobile Certificate No. 159032) or B: dimethylguanidine was added to powdered poly(2,6-dimethyl-1,4-phenylene oxide), in both cases in an amount of 2 parts per 100 parts of polymer. To ensure homogeneity of the mixture, the powdered material was impregnated with a solution of the additive, thoroughly mixed and dried. One batch of powdered polyphenylene oxide was used to prepare these and other examples of the samples, the viscosity number of which was 56.5 ml/g measured in chloroform at a concentration of 0.3 g/100 ml of solution, at a temperature of 25 °C,

The mixtures were melted on a laboratory screw extruder and the extruded strand was granulated. Plates were pressed from the granulate and test specimens were prepared by mechanical machining for determining the basic mechanical, electrical and thermal properties and thermo-oxidative stability. Plates clad with Cu foil (35 pm) were also prepared for determining the peel strength. The properties of both compared materials are given in Table 1.

Table I

Property Mixture A Mixture B Tensile strength, micro-bodies with a cross-section of 1 mm2, strain rate 50 mm/min, 23 °C, MPa 72.0 67.8 Notch toughness, flSH 640612, test specimens groove 3, 23 °C, w/gb? 0.55 0.56 Vicat softening temperature, ÍÍSN 640521, method B °C 201 203 Loss factor, CSN 346466, 50 Hz 23 °C 5.1.10-4 5.0.10-4 Specific internal resistance* ČSN 346460, 23 °Ccm 1.1.1018 8.9-1017 Peel strength, CSN 644810, N/cm 7.2 12.3

thermo-oxidative stability at 130 °C (time after which resistance to repeated bending decreases to half an hour 360 420 201 766 Example 2

To a mixture of 95 parts of poly(2,6-dimethyl-1,4-phenylene oxide) and 5 parts of ethylene-propylene rubber, either A: 4.5 parts of N,N’-dimethylhexamethylenediamine or B: 4.5 parts of o-tolylbiguanidine was added in the same manner as in the previous example. The measurement results are summarized in Table II.

Table II

Property mixture A mixture B tensile strength, 23 °C MPa 69.9 70.0 notch toughness, 23 °C 3/va? 1.47 1.60 Vicat softening temperature °C 199 203 loss factor, 50 Hz, 23 °C 5.3.10-4 5.0.10-4 detto 100 °C 7.2.10-4 7.1.10-4 detto 150 °C 19.10-4 8.4.10-4 specific internal resistance, 23 °C cm 7.5.1.017 4.2.1017 peel strength H/cm 7.6 13.1 thermo-oxidative stability at 130 °C h 450 500 Example 3

To a mixture of 70 parts of poly(2,6-dimethyl-1,4-phenylene oxide) and 30 parts of Krasten 562 high-impact polystyrene was added either A: 1.5 parts of N,N'-dimethylhexamethylenediamine or B: 1.5 parts of phenyl-o-tolylxylylguanidine. The mixtures were processed and evaluated as in the previous examples, the results are given in Table III. 201 766 5

Table of lilies

Property mixture A mixture B tensile strength, 23 °C MPa 62.6 62.4 notch toughness, 23 °C J/om2 0.57 0.56 softening temperature according to Vlčat °C 165 166 loss factor, 50 Hz, 23 °C 7.0.10"4 5.8.10-4 detto 100 °C 13.Ο.1Ο-4 6.5.10-4 detto 150 °C 110.10-4 26.10-4 specific internal resistance, 23 °C cm 2.4.1017 6.6.1017 peel strength N/cm 6.5 10.7 thermo-oxidative stability at 130 °C h 60 300 Example 4

To a mixture of 50 parts of poly(2,6-dimethyl-1,4-phenylene oxide), 43 parts of clear polystyrene Krasten 127 and 7 parts of butyl rubber was added either A: 2.5 parts of N,N'-dimethylhexamethylenediamine or B: 2.5 parts of ethylguanidine. The mixtures were processed and evaluated as described above. Table IV summarizes their properties.

Table IV

Property mixture A mixture B tensile strength, 23 °C MPa 58.1 61.8 notch toughness, 23 °C J/om2 0.72 0.81 softening temperature according to Vlčat °C 145 143 loss factor, 50 Hz, 23 °C 6.0.10-4 6.1.10-4 detto 100 °C 30.0.10-4 14.0.10-4 detto 150 °c 150.10-4 7.5.10-4 thermo-oxidative stability at 130 °C 225 420

Claims (1)

EXAMPLE 5 To a mixture of 50 parts of poly (2,6-dimethyl-1,4-phenylene oxide), 45 parts of polystyrene sulfur-127, 5 parts of ethylene-propylene rubber, 1 part of TiOg and a stabilizer were added BuA; 3 parts of N N '-dimethylhexamethylenediamine or B: 3 parts of phenylbiguanidine. The compositions were processed and evaluated as in the previous examples, the properties are shown in Table V. Table V Property Mixture A Mix B Tensile Strength, 23 ° C MPa 63.7 59.4 Notched Impact, 23 ° C / cm 2 0.84. 0.79 Vicat softening temperature ° C 140 143 loss factor, 50 Hz, 23 ° C 19.10-4 8.5-10-4 detto 100 ° C 23.1O-4 12.10-4 detto 150 ° C 300.1O-4 31.10 -4 Specific internal resistance, 23 ° C cm 6.8.1017 8.0.1017 Thermo-oxidative stability at 130 ° C h 510 750 Invention Materials for low-voltage electrical engineering based on polyphenylene oxide and its mixtures with other polymers and possibly other additives such as stabilizers pigments, lubricants and fillers, characterized in that it contains 0.1 to 5 parts by weight of guanidine (I) (I) or biguanidine (IX) N - RJ (II) derivatives, R 1 where R 1 to R 7 is hydrogen, methyl, ethyl , phenyl, tolyl or xylyl, based on 100 parts by weight of polymer or mixtures thereof in the material.