JPS59131643A - Vinyl chloride resin composition - Google Patents

Abstract

PURPOSE:To prevent the lowering of mechanical properties, oil resistance and moldability caused by the addition of a large amount of filler, by compounding a vinyl chloride polymer uniformly with a specific crosslinked ethylene-vinyl acetate-vinyl chloride terpolymer. CONSTITUTION:The objective composition is prepared by compounding (A) 100pts.wt. of a vinyl chloride polymer uniformly with (B) >=20pts.wt. of a crosslinked ethylene-vinyl acetate-vinyl chloride terpolymer having a gel fraction of 5-50% and obtained by the graft polymerization of (i) 20-170pts.wt. of vinyl chloride to (ii) 100pts.wt. of an ethylene-vinyl acetate bipolymer containing 30-70wt% of vinyl acetate unit. When the terpolymer is crosslinked to attain a gel fraction of 10-30%, the improving effects to the mechanical properties and the oil resistance become particularly remarkable.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vinyl chloride resin composition with improved mechanical properties and oil resistance.

Conventionally, vinyl chloride resin compositions are inexpensive plastics with excellent flame retardancy and processability, and have therefore been widely used as wire coating materials.

However, in recent years, it has become clear that electric wires and cables coated with vinyl chloride resin compositions are highly combustible in the event of a fire when several or more wires are grouped together, and a higher degree of flame retardancy is required. . Furthermore, there is also the problem that hydrochloric acid gas generated during combustion causes secondary damage to human bodies, equipment, etc., and improvement of this problem has become an important issue.

Therefore, as a method for improving these problems, a method is well known in which a large amount of a flame retardant, a flame retardant inorganic filler, a hydrochloric acid gas scavenger, etc. is blended into a vinyl chloride resin composition.

However, as a result, a problem arose in that not only mechanical properties and oil resistance but also extrusion processability deteriorated significantly.

Among these methods, methods for improving mechanical properties include blending polyfunctional compounds with vinyl chloride resin, blending Sakai bridging agents such as organic peroxides, or irradiating ionizing radiation such as phosphorus electron beams. A known method is to form a three-dimensional network structure in the tree by applying a crosslinking method such as irradiation to improve the tree.

However, in the case of the improvement method using electron beam irradiation, when the size of the wire or cable to be irradiated becomes thick, it becomes difficult to irradiate uniformly, and when the coating thickness becomes thick, an electron beam accelerator with high energy is required. There are some types of meh, such as Naru, whose scope of use is limited. On the other hand, the chemical crosslinking method using organic peroxides makes it possible to produce all kinds of molded products, but organic peroxides do not contribute to the crosslinking of vinyl chloride resin, but rather promote the decomposition reaction. For,
A practical manufacturing method has not yet been established.

On the other hand, as a method for improving the oil resistance, a method is known in which vinyl chloride resin is modified by blending a polymer that is compatible with the vinyl chloride resin. For example, nitrile butadiene comb, ethylene-vinyl acetate copolymer, etc. have shown good results in improving the oil resistance of vinyl chloride resin, but the resulting compositions have poor extrusion processability, and This caused problems such as decreased cold resistance.

As a result of intensive research into the development of a vinyl chloride resin composition that does not impair its mechanical properties, oil resistance, or processability even when a large amount of filler is added, the present inventors found that This has led to the present invention.

In other words, ethylene-vinyl acetate-vinyl chloride 8-component copolymer (hereinafter referred to as vinyl chloride graft polymer), which is conventionally considered undesirable as a modifier for vinyl chloride resin because it significantly reduces oil resistance, can be used as a modifier for vinyl chloride resin. A composition obtained by lightly crosslinking this vinyl chloride graft polymer in advance and blending a small amount of this with vinyl chloride resin It has been discovered that a vinyl chloride resin composition having excellent mechanical properties, oil resistance, extrusion processability, etc. can be obtained.

However, in the past, crosslinked polymers had a high softening temperature, as can be seen from the purpose of crosslinking, and could not be heated and melted, making it impossible to cross-wire them using normal manufacturing equipment. , this vinyl chloride graft polymer has a gel fraction (2
If the insoluble matter after immersion for 4 hours (weight factor) is 50 or less, it can be sufficiently mixed with other resins, and the composition blended with vinyl chloride resin has poor mechanical properties and oil resistance. Sexuality etc. were also improved.

That is, in the present invention, 100 parts by weight of vinyl chloride polymer (a), 100 parts by weight of an ethylene-vinyl acetate binary copolymer containing 80 to 70% by weight of vinyl acetate, and 2 parts by weight of vinyl chloride
Gel fraction of 5 to 5, obtained by graft polymerization of 0 to 170 parts by weight
50% crosslinked ethylene-vinyl acetate-vinyl chloride 8-component copolymer (b) 20 parts by weight or more is uniformly blended (?L+b
) This invention relates to a vinyl chloride resin composition with improved mechanical properties and oil resistance.

As a method for lightly crosslinking the vinyl chloride graft polymer, organic peroxides such as dicumyl peroxide, 1,8-bis(t-butylperoxyinglovyl)benzene, 2,5-dimethyl-2, 5-di(1
-butylperoxy)hexine-8, t-butylcumyl peroxide, and other chemical crosslinking agents, and other methods include methods using ionizing radiation such as electron beams, gamma rays, and X-rays.

However, their blending amount, irradiation conditions, etc. are determined by the gel fraction of the vinyl chloride graft polymer (24
It is desirable that the insoluble weight (clI) after immersion for a period of time is between 5 and 50. That is, this limitation is because if the amount is less than 5%, the effect of crosslinking will be too weak to appear, and if it exceeds 50%, the crosslinkability and compatibility with the vinyl chloride polymer will be significantly reduced.

Particularly good performance is shown when the gel fraction is 10 to 30.

Ethylene-vinyl acetate obtained by crosslinking in this way
If the amount of graft-polymerized vinyl chloride in 100 parts by weight of the vinyl chloride 8-component copolymer is less than 20 parts by weight, extrusion processability will deteriorate when mixed with vinyl chloride resin, so it is not possible, and if it exceeds 170 parts by weight. This is not allowed because cold resistance deteriorates when mixed with vinyl chloride resin.

Next, the crosslinked vinyl chloride graph Jmer thus obtained,
That is, the blending amount of the aforementioned ethylene-vinyl acetate Reference Example I vinyl 8-component copolymer (b) is as follows:
Although it is desirable to have at least 20 parts by weight of polymer (b), it is not possible due to the characteristics of vinyl chloride graft polymers and the inability to crosslink. The above can be freely selected depending on the purpose.
Maap v7
-1 The above (a) vinyl chloride polymer is a vinyl chloride polymer with an average particle crosslinking method of 500 to 4,000, after salt kneading, Futwarutoko, vinyl acetate-vinyl chloride copolymer, acton beam irradiation! Examples include methyl-vinyl chloride copolymer. In addition, in carrying out the present invention, 11
It may be obtained by adding compounding agents, such as plasticizers, colorants, fillers, lubricants, etc., which are usually added to the terpolymer as a chloride to the composition. The present invention will be explained in more detail by referring to reference examples, comparative examples, insoluble matter, weight, etc.
This is shown below.

However, the game vinyl grafted polymers, i.e. Lefu Vinegar Vinyl-Vinyl Chloride 8 Yuan Co. The characteristics are shown in Table 1.

In order to demonstrate the effect, in the chemical crosslinking method, a predetermined amount of D'OP (dicumyl peroxide) was thoroughly kneaded at 1.0°C, and then a 1 mm thick sheet was formed at a temperature of 160°C for 20 minutes. At a roll temperature of 180[deg.] C., the rnmnm-tow melted and was loaded with a predetermined amount of weight using a Cockron-type electron beam accelerator.

Stabilizer to suppress decomposition during reaction Add basic lead sulfate to 1000 parts of the polymer. Parts by weight were blended.

The results of all measurements of the gel fraction (quantity after 24 hours immersion in 1zO℃ Sanon solution) of the crosslinked sheet are shown in Table 1. In the table, 0 indicates the degree of coloring after crosslinking, with a pol fraction of 50 or more. Now, light brown to brown Examples 1 to 6; Comparative Examples 1 to 10 Based on the knowledge obtained from the above reference examples, vinyl chloride graft polymers with various gel fractions were selected, and the results are shown in the footnotes of Table 2 below. The vinyl chloride polymer composition of 17
After kneading for about 10 minutes with a heated roll at 0°C, the mixture was heated to 170°C.
A sheet with a thickness of 1 mm was prepared by press molding for 0 minutes.

On the other hand, as a comparative example, in chemical crosslinking of a vinyl chloride polymer composition using a vinyl chloride graft polymer that has not been crosslinked in advance, DOP' ((i) per 100 parts by weight of the vinyl chloride graft polymer in the composition was 0.
In addition to the same formulation as in the footnote to make 0.4 parts by weight, 170℃
A 1 mm thick sheet was produced by press molding for 10 minutes.

In addition, in the electron beam crosslinking method, a 1 mm mm sheet molded with the same composition as the footnote in Table 2 was irradiated with an electron beam at a dose of 8 Mra6.

Table 2 also shows the workability during roll kneading, mechanical properties, and oil resistance test results obtained in this manner.

As a result, it is clear that the composition containing the vinyl chloride graft polymer, which has been crosslinked in advance to have a gel fraction of 10 to 80%, has significantly improved mechanical properties and oil resistance, and has a gel fraction of 5 to 80%. If eo<, there is a possibility of improving the characteristics, but processing was difficult.

However, when the gel fraction exceeds 60, kneading properties are extremely reduced, sample molding becomes difficult, and performance is significantly reduced.

In addition, in the chemical crosslinking method in which a crosslinking agent is added at the time of crosslinking without crosslinking in advance, the sample not only turns brown but also does not contribute to improving oil resistance. On the other hand, in the electron beam crosslinking method, no improvement in mechanical strength can be expected, and the method is only marginal.

The first line of page 11 of the specification is corrected as follows.6 "Examples 1 to 4; Comparative Examples 1 to 12" The second table of page ta of the same specification is corrected as follows.

Claims (1)

[Claims] L(a) For 1000 parts of vinyl chloride polymer, (b
) Vinyl acetate has a gel fraction of 5 to 50% by graft polymerizing 20 to 170 parts by weight of vinyl chloride to 100 parts by weight of an ethylene-vinyl acetate binary copolymer containing vinyl acetate of 80 to 70''fE. 20 parts by weight or more of a crosslinked ethylene-vinyl acetate-vinyl chloride 8-component copolymer is uniformly blended (a+b
) A vinyl chloride resin composition with improved mechanical properties and oil resistance.