JPS61264038A - Soft vinyl chloride resin composition for shoes - Google Patents

Abstract

PURPOSE:To produce the titled composition having excellent moldability, resistant to oil and bending, and suitable for the forming of shoes, especially the integral molding of boots, by compounding a specific ethylene/vinyl chloride resin in place of conventional suspension-polymerized straight PVC resin. CONSTITUTION:(A) 100pts.(wt.) of an ethylene/vinyl chloride copolymer resin having an ethylene content of 1-2% and a polymerization degree of 1,050-2,800 is compounded with (B) 60-90pts. of a phthalic acid ester plasticizer (e.g. dibutyl phthalate) having a molecular weight of 270-450, (C) 5-50pts. of a high- molecular plasticizer having a molecular weight of 1,000-9,000 (e.g. adipic acid polyester plasticizer), (D) 0-20pts. of an acrylonitrile-butadiene rubber and (E) 1.5-3.5pts. of a stabilizer (e.g. a tin compound such as dibutyltin dilaurate).

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a soft vinyl chloride resin composition for injection molded shoes. The present invention relates to a resin composition for shoe molding, particularly for integrally molded boots or shoe soles, which has oil resistance and bending resistance.

(Prior Art) Conventionally, soft vinyl chloride resin compositions used as materials for integral injection molded boots or soles have a polymerization degree of 1050 to 1.
About 300 suspension polymerized straight polyvinyl chloride (PV
C) For 100 parts by weight of resin, add a phthalate ester plasticizer, such as di-2-ethylhexyl phthalate (D
60 to 120 parts by weight of OP), and O to 3 parts of additives, such as so-called acrylonitrile rubber (NBR).
A formulation is used consisting of 0 parts by weight of epoxidized soybean oil, 2 to 3 parts by weight of epoxidized soybean oil, and 2.0 to 3.5 parts by weight of stabilizer.

These compounds are then integrally injection molded into desired boots, or into regular shoe soles.

(Problems to be Solved by the Invention) By the way, shoes manufactured by injection molding using the compounded composition as described above are not allowed to be stored in oil stations, meat slaughterhouses, cafeteria kitchens, etc. If you use it for a long time,
The blended phthalate ester plasticizer has a molecular weight of 270~
450, which is relatively low, causes the problem that the dissolvable agent is extracted by the oil, and as a result, the shoe itself becomes hard, and the shoe or sole may crack due to bending.

As a method to solve the problem of cracking caused by bending, the degree of polymerization of suspension polymerization straight) PVC#I resin was adjusted to 1.8.
00 to about 3,000, blending other polymers with good oil resistance such as medium-high acrylonitrile butadiene copolymer (NBR), chlorinated polyethylene, thermoplastic polyurethane resin, etc. A method of incorporating a high molecular weight plasticizer having a molecular weight of about 1.000 to 8.000, such as an adipic acid polyester plasticizer, a phthalic acid polyester plasticizer, a sebacic acid polyester plasticizer, etc., has been proposed.

However, in each of the above measures, originally
Polymerized straight PVC itself lacks bending resistance, and its high viscosity impedes the flow of the resin, which inevitably results in poor processability. In addition, incorporating a high amount of high molecular weight plasticizer leads to an increase in the cost of the material, resulting in the problem that the resulting shoes themselves have to be expensive.

Therefore, as a result of intensive research into the development of a resin composition for shoe molding that does not impede the injection moldability of the resin, has excellent processability, oil resistance, and bending resistance, the present inventor found that the conventional suspension polymerization strain ) When ethylene/vinyl chloride copolymer resin was used instead of PVC resin, even if the amount of expensive high molecular weight plasticizers and additives such as NBR was reduced,
It was confirmed that a resin composition for shoe molding was obtained, in which the bending resistance of the obtained product after immersion in oil was significantly improved, and the cold resistance was also improved, and therefore, the resin composition was used. They made the new discovery that boots, etc., made by integral injection molding have excellent bending resistance and oil resistance, and completed the present invention.

(Means for Solving the Problems) - That is, the present invention is a soft vinyl chloride resin composition for injection molded shoes, the composition comprising an ethylene/vinyl chloride copolymer containing 1 to 4% of ethylene. 100 parts by weight of resin, 60 to 80 parts by weight of phthalate plasticizer, 5 to 50 parts by weight of high molecular weight plasticizer, 0 to 20 parts by weight of acrylonitrile-butadiene rubber, 1.5 to 3.5 parts by weight of stabilizer, This corresponds to an oil-resistant and bend-resistant resin composition for injection molded shoes.

(Function) In the above resin composition of the present invention, a polyethylene/vinyl chloride copolymer resin is used in place of the conventional suspension polymerized straight (PVC) resin. The resin preferably has an ethylene content of 1 to 2% and a polymerization degree of 1050 to 2800.

In addition, phthalate ester plasticizers have a molecular weight of about 270 to 450, and specifically include dibutyl phthalate-1-(DBP), di-2-ethylhexyl phthalate-1 (DOP), and di-n -Octyl phthale-1・
(n-DOP), butyl lauryl phthalate-1-(BLP)
), Shirauri' Luftale 1. (DLP) or butylbenzyl phthalate (BBP).

On the other hand, high molecular weight plasticizers have a molecular weight of i,ooo to 9.
000, such as adipic acid polyester plasticizers, phthalic acid polyester plasticizers, and sebacic acid polyester plasticizers, which have molecular groups within this range.

In addition, the stabilizer may be a stabilizer for soft vinyl chloride resin, and is not particularly limited, but it may be a tin-based compound stabilizer, such as dibutyltin maleny-1, dibutyltin maleny I, or dibutyltin mercaptide. etc. are preferred.

The soft vinyl chloride resin composition for injection molded shoes of the present invention can reduce the amount of expensive high molecular weight plasticizers or NBR added, especially in the formulation of the components listed below.

Moreover, considering that these substances impair cold resistance, they can be said to be particularly preferable.

(Example) The oil-resistant and bend-resistant resin composition for injection molded shoes of the present invention will be described below based on Examples.

The composition constituting the resin composition of the present invention is as described above; 100 parts by weight of ethylene/vinyl chloride copolymer resin containing 1 to 4% ethylene, 60 to 80 parts by weight of phthalate ester plasticizer, high molecular weight It consists of 5 to 50 parts by weight of a plasticizer, 0 to 20 parts by weight of acrylonitrile-butadiene rubber, and 1.5 to 3.5 parts by weight of a stabilizer. can be done as follows:

That is, 10 of the ethylene/vinyl chloride copolymer resin
0 parts by weight, the desired amounts of a phthalate ester plasticizer, high molecular weight plasticizer, and stabilizer were added to a Henshil mixer, and the compound temperature was raised to 120' to 120'. agents, high molecular weight plasticizers, and stabilizers are completely absorbed into the ethylene/vinyl chloride copolymer resin. Thereafter, the compound is cooled to e o 'c, and a desired amount of powdered NBR is added and stirred to obtain the desired resin composition. This resin composition can be molded into, for example, integrally molded boots or shoe soles using a desired injection molding machine.

Specific formulation examples thereof can be summarized as follows.

Implementations 1 to 3: - Test pieces were prepared using equivalent amounts of each component shown in the following table, and their physical and chemical properties were examined.

For 100 parts by weight of ethylene/vinyl chloride copolymer resin (suspension polymerization straight in the comparative example) (PVC), each part by weight of DOP and high molecular weight plasticizer (
Adipic acid polyester (PN-250) and a tin stabilizer are mixed and kneaded for 5 minutes at a roll temperature of 180°C. Thereafter, NBR (Chemi Gum P-83) was added on a roll and kneaded for 10 minutes to obtain a mixture. This mixture was heated in a steam press at 160° C. for 10 minutes under pressure, and then cooled to form a sheet. The test results are summarized in the table.

(Parts by weight) *1: Presence or absence of cracks by Roe-Mattia bending tester As is clear from this result, the composition using the ethylene/vinyl chloride copolymer resin of the present invention has a high molecular weight. Plasticizer (PN-250 in the examples)
as well as NBR (e.g. NBR Chemi Gum P-83')
Even if the blending amount is reduced (note: it is reduced according to Examples 1 to 3), the bending resistance is superior to that of the comparative example, and the cold resistance (note: flexibility temperature) is proportional to that. It turns out that the processability (viscosity) is improved.

In particular, De-
It is found that the Mattia bending of the present invention is several orders of magnitude better than that of the comparative example, and the oil resistance is also good.

(Effects of the Invention) As described above, the soft vinyl chloride resin composition for injection molded shoes of the present invention has excellent oil resistance, has significantly improved flexibility, and has good processability, and can be used, for example, as rubber boots. Even when integrally molded, the product has particularly excellent durability.

In particular, maintaining good viscosity eliminates insufficient injection of resin, improving productivity and reducing the amount of expensive high molecular weight plasticizer used, reducing costs, and has great practical value. You can say that.

In addition, in conventional boots made of suspension polymerized PVC, a reinforcing piece was attached to the upper heel part of the boots to ensure bending resistance, but the ethylene/PVC of the present invention
Flexibility is improved by using vinyl chloride copolymer resin, and there is no need to attach any kind of reinforcing piece.From this point of view, it is an excellent product as it simplifies the production process and reduces the weight of the shoe. You can say that.

Claims (7)

[Claims] (1) 100 parts by weight of ethylene/vinyl chloride copolymer resin containing 1 to 4% ethylene, 60 to 90 parts by weight of phthalate plasticizer, 5 to 50 parts by weight of high molecular weight plasticizer, 0 parts by weight of acrylonitrile-butadiene rubber An oil-resistant and bend-resistant resin composition for injection molded shoes, comprising: 1.5 to 20 parts by weight of a stabilizer; and 1.5 to 3.5 parts by weight of a stabilizer. (2) The resin composition according to claim 1, wherein the ethylene/vinyl chloride copolymer resin has an ethylene content of 1 to 2% and a degree of polymerization of 1050 to 2800. (3) The molecular weight of the phthalate plasticizer is 270-4
50. The resin composition according to claim 1, which has a molecular weight of 50. (4) High molecular weight plasticizer has a molecular weight of 1,000 to 9,000
The resin composition according to claim 1, which is a resin composition according to claim 1. (5) The resin composition according to claim 4, wherein the high molecular weight plasticizer having a molecular weight of 1,000 to 9,000 is an adipic acid polyester plasticizer, a phthalic acid polyester plasticizer, or a sebacic acid polyester plasticizer. (6) The resin composition according to claim 1, wherein the stabilizer is a tin-based compound stabilizer. . (7) The resin composition according to claim 6, wherein the tin-based compound stabilizer is dibutyltin dilaurate, dibutyltin maleate, or dibutyltin mercaptide.