JPS61204245A - Polyolefin composition - Google Patents

Abstract

PURPOSE:To obtain the titled composition having excellent heat-resistance and voltage-resistance and suitable for the distributor cap and rotor of an automobile, by adding a small amount of a foaming agent, a silane coupling agent and an organic peroxide to a composition composed of a polyolefin and mica at a specific ratio. CONSTITUTION:The objective composition is produced by compounding (A) 100pts.wt. of a composition composed of (i) 95-40wt%, preferably 90-40% polyolefin (preferably propylene polymer) and (ii) 5-60%, preferably 10-60% mica [preferably phlogopite of formula K2Mg6(Si3Al)2O20(OH)4 or muscovite of formula K2Al4(Si3Al)2O20(OH)4] with (B) 0.05-0.5pts. of a foaming agent (e.g. azodicarbonamide), (C) 0.5-5pts. (based on 100pts. of mica) of a silane coupling agent (e.g. triethoxypropylamino-silane) and (D) 0.01-1pt. (based on 100pts. of mica) of an organic peroxide (e.g. di-t-butyl peroxide).

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a voltage-resistant composition containing polyolefin, an inorganic filler, and a blowing agent, and in particular, use in automobile distributor caps and rotors containing mica and a blowing agent. The present invention relates to a polyolefin composition having good heat resistance and voltage resistance suitable for

Conventional technology Attempts have been made to add arc resistance and tracking resistance to polyester resins, phenolic resins, polyolefin resins, etc., by adding inorganic fillers to them for use as structural materials and insulating materials for electrical components such as automobiles. . However, the performance required of distributor caps and rotors for recent automobiles has increased in order to cope with new pollution prevention technology and higher engine performance, and to withstand higher voltage and to withstand the heat that increases due to the application of high voltage. Durability is becoming a necessity.

For this purpose, large amounts of inorganic fillers are added or the thickness of the molded product is made thicker, but this results in voids forming inside the molded product and sink marks on the surface of the molded product. However, in order to prevent the occurrence of cracks and sink marks on the molded product due to the addition of inorganic fillers and thickening of the wall thickness of the molded product, foam molding is used. The technology to do this is disclosed in JP-A-53-50251 and JP-A-59-
No. 20333, Japanese Unexamined Patent Publication No. 59-22956, etc., but none of these technologies have been recognized as having good voltage resistance and heat resistance suitable for use in automobile distributor caps and rotors. 9.

The present invention solves the above-mentioned problem, that is, voltage resistance that prevents the generation of voids inside the molded product and prevents the occurrence of sink marks and crevices 9 on the surface of the molded product when producing the molded product from a polyolefin composition containing an inorganic filler. The object of the present invention is to provide a polyolefin composition for producing automobile distributor caps and rotors with good heat resistance.

Means for Solving the Problems The inventors conducted various studies and found that by adding mica to polyolefin and performing cross-linking foam molding in the presence of a silane coupling agent and a foaming agent, voids inside the molded product were completely prevented. The present invention was completed by discovering a polyolefin composition suitable for automotive distributor caps and rotors that can significantly improve voltage resistance and heat resistance.

That is, the present invention uses 0.05 to 0.5 parts by weight of a blowing agent to 100 parts by weight of a composition containing 40% by weight of polyolefin 95S and 5 to 60% by weight of mica, and a silane coupling agent to 100 parts by weight of mica. This is a voltage-resistant polyolefin composition characterized in that it contains 0.5 to 5 parts by weight and 0.01 to 1 part by weight of an organic peroxide.

The configuration of the present invention will be explained in detail below.

Polyolefins used in the present invention include high-, medium-, and low-pressure polyethylene, polypropylene, polymers such as polybutene-1, ethylene-propylene copolymers, ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, ethylene-a, It is an olefin elastomer such as an olefin copolymer, and one of these polymers and elastomers
A species or a mixture of two or more species. Among these polymers, propylene-based polymers such as polypropylene, propylene-ethylene random or block copolymers, and propylene-1-butene copolymers are particularly effective, and are present in the composition in a range of 95 to 40%. It is preferably used in an amount of 90 to 400 parts by weight. In addition, modified polyolefin chlorinated polyethylene, 38R is added to the above olefin resin.

Polyinobutylene, polybutadiene, etc. may be added as a modifier. Other colorants, nucleating agents, anti-aging agents, ultraviolet absorbers, flame retardants, crosslinking aids, foaming aids,
Additives such as lubricants may also be added.

The average particle size of the mica to be blended in the present invention is 1 to 1.
Examples include white mica such as 500μ white mica, red mica, soda mica, silk mica, vanadium mica, and illite, and black mica such as black mica, gold mica, and Chinwald mica, among which, for example, structural formula For example, gold mica shown as 2Mg6(S4sA4)202o(OH)4 or 2A44(813A/)2Q2o(
White mica represented by OH)4 is preferred. The blending amount of mica is preferably 5 to 60% by weight, particularly 10 to 60% by weight.
It is preferable to use it within the range of . If it exceeds 60% by weight, moldability will deteriorate, and if it is less than 5% by weight, electrical resistance will deteriorate.

Silane coupling agent in the present invention and general formula R'5
It is an organic silane compound represented by i(OR2), and R
1 is an alkyl group or an aryl group having a polar functional group having an affinity with acids, acid anhydrides, or esters thereof. Specific examples of R1 include r-aminopropyl, up-(aminoethyl)r-aminopropyl,
r-freidopropyl, r-glycidoxyprovir, -
Examples include mono(3,4-epoxychlorohexyl)ethyl, r-mercaptopropyl, paraaminophenyl, etc. R2 is an alkyl group or an aryl group, and specific examples thereof include methyl, ethyl , propyl,
Examples include butyl, β-meth, and cudiethylphenyl. Among these organic silane compounds, triethoxypropylaminosilane, r-ureidopropyltriethoxysilane, and the like are preferred. The amount of the organic silane compound to be blended is preferably 0.5 to 5 parts by weight per 100 parts by weight of added mica.

The organic peroxide used in the present invention is a peroxide that decomposes upon heating to generate radicals, such as di-t-butyl peroxide, dicumyl peroxide, t-butylcumyl peroxide, α, αI-bis(t -butylperoxyph p-diimprobylbenzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2
,5-dimethyl-2,5-di(t-butylperoxy)
One type or 2s or more of hexin-3 or the like is used. A crosslinking aid may be used if necessary. The amount of organic peroxide to be blended is preferably 0.01 to 1 part by weight per 100 parts by weight of mica.

The blowing agent used in the present invention is preferably a thermally decomposable blowing agent that decomposes when heated and generates gas relatively rapidly, such as azodicarbonamide, hydradicarbonamide, dinitron bentametherenetetramine, p, p'-o It is one kind or a mixture of two or more such as bisbenzenesulfonyl hydrazide. The amount of the blowing agent can be selected depending on the desired expansion ratio of the foam, but in the foam of the present invention, it is 0.0 parts by weight per 100 parts by weight of the polyolefin resin composition.
It is preferable to add 5 to 0.5 parts by weight in order to exhibit voltage resistance and heat resistance.

In the present invention, the above polyolefin is mixed with the above mica, a silane coupling agent, an organic peroxide, a blowing agent, and other additives as necessary, and granulated using various extruder noises. Of course, this step requires granulation at a resin temperature that is about 20-50°C lower than the decomposition temperature of the organic peroxide and blowing agent. A molded product can be molded from the obtained pellets by injection molding, extrusion molding, etc., but it may also be molded directly from a mixture of each component.

For foam molding, either the masterbatch method or the triblend method may be used.

Effects of the Invention Molded products made from the polyolefin composition of the present invention have a uniform cross-linked foam structure despite the high filler content, so they have good voltage resistance and heat resistance, and are suitable for automobile distributor caps and rotors. It can be used in applications that require high withstand voltage such as.

Examples Examples of the present invention are shown below. The test method in the examples is as follows.

1] Measurement of withstand voltage (promotion): Measure a test piece with a thickness of 12111 at a frequency of 700 G/S, a voltage of 25 KV, and a temperature of 100°C. 2) Heat resistance: Ai9TM D-648 (
4.4 g thick test piece, thermal deterioration temperature (EDT) at 264 psl All measurements] Examples 1 to 7, Comparative Examples 1 to B Polypropylene (MI: 20360% by weight and white mica [
Table 1 shows triethoxyglobylaminosilane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexine-3, and hydradicarbonamide in 100 parts by weight of a mixture consisting of 40% by weight [particle size 27μ]. Add each amount in the blended amount and mix with a high speed mixer.
The mixture was melt mixed and granulated using a shaft kneader at a cylinder temperature of 190-220°C. The obtained pellets were molded into test pieces under injection conditions of a cylinder temperature of 250° C. and an injection pressure of 600 kl/IB2, and the withstand voltage and heat resistance were measured. The results are shown in Table-1.

For comparison, the same evaluation was conducted for the case in which the silane coupling agent 1 and the blowing agent were not used, and the results are shown in the table below.
1jC was also written.

Claims (1)

Scope of Claims: 0.05 to 0.5 parts by weight of a blowing agent to 100 parts by weight of a composition containing 95 to 40% by weight of polyolefin and 5 to 60% by weight of mica, and a silane cup to 100 parts by weight of mica. A voltage-resistant polyolefin composition comprising 0.5 to 5 parts by weight of a ring agent and 0.01 to 1 part by weight of an organic peroxide.