JPS5836016B2 - resin composition - Google Patents

Description

[Detailed description of the invention] The present invention relates to a resin composition having excellent transparency.

More specifically, it is a soft vinyl chloride-based graft copolymer produced by polymerizing a vinyl chloride monomer or a monomer mixture mainly composed of vinyl chloride monomers in the presence of an ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVA). The present invention relates to a resin composition comprising a terpene resin and having excellent transparency.

Conventionally, in the field of soft polyvinyl chloride (hereinafter abbreviated as PVC), the volatilization or migration of plasticizers has been a problem, and blends of EVA and PVC or the addition of vinyl chloride to EVA have been used for the purpose of plasticizing and softening. Grafting has been done.

It is well known that when the EVA content of an EVA vinyl chloride graft copolymer is gradually increased, the properties of the graft copolymer change from hard to semi-hard to soft. It is also known that it is possible to obtain graft copolymers with a high EVA content.

However, although the EVA monochloride graft copolymer with a high EVA content has increased flexibility, some problems remain unsolved, and as a result, it is limited to soft PVC plasticized with phthalate esters. It has only reached the point where it can be replaced in the areas where it has been replaced.

In particular, transparency has been an unavoidable drawback until now, and soft EVA vinyl monochloride graft copolymers have not been able to be used in applications requiring transparency.

The present invention aims to provide a simple and economical solution to the transparency problem that has been a drawback of flexible EVA vinyl monochloride kraft copolymers.

To achieve this objective, the present invention uses 30 to 85 parts by weight of vinyl chloride monomer or a heptanomer mixture based on vinyl chloride monomer in the presence of 15 to 70 parts by weight of EVA with an ethylene content of 35 to 75% by weight. A soft vinyl chloride graft copolymer having excellent transparency is obtained by blending 0.5 to 50 parts by weight of a terpene resin with 100 parts by weight of a soft vinyl chloride graft copolymer obtained by polymerizing I was able to get it.

Until now, despite the importance of the transparency of soft vinyl chloride graft copolymers, only a few improvements have been made by graft polymerization, and improvements by the simple method of blending are unknown. do not have.

The present inventors have discovered that while maintaining the performance of a soft vinyl chloride-based graft copolymer, the transparency can be easily improved by blending a specific proportion of terpene resin, and have arrived at the present invention.

The present invention will be explained in detail below.

? The soft EVA vinyl monochloride graft copolymer used in the invention is obtained by polymerizing 30 to 85 parts by weight of a vinyl chloride monomer or a monomer mixture mainly composed of vinyl chloride monomers in the presence of 15 to 70 parts by weight of EVA.

Suspension polymerization is usually used as a method for graft polymerizing vinyl chloride monomers to EVA, but any method such as emulsion polymerization, bulk polymerization, or solution polymerization may be used.

The weight ratio of EVA and vinyl chloride monomer is 70/30
~15/85, and if it is larger than 70/30, it lacks the flexibility characteristic of soft vinyl chloride resin and becomes difficult to handle due to blocking, etc.
If it is less than that, flexibility cannot be obtained.

EVA may be manufactured by any conventionally known process such as high pressure method or solution method.
~75% by weight is used.

EVA with an ethylene component of less than 35% by weight has poor low-temperature properties, so the resulting graft copolymer lacks low-temperature flexibility;
If the amount exceeds 5% by weight, EVA becomes hard and is not suitable for obtaining a soft vinyl chloride graft copolymer.

In addition, the melt index of EVA is 0.1 to 40.
A range of 0 fl/10 m#+ is used.

Monomers that can be copolymerized by mixing with vinyl chloride monomers include acrylic acid derivatives and methacrylic acid derivatives such as ethyl acrylate, methyl acrylate, octyl acrylate, and methyl methacrylate, olefins such as ethylene and propylene, fumaric acid, and maleic acid esters. , vinyl ethers and vinyl esters such as vinyl acetate and vinyl propionate.

Examples of the terpene resin used in the present invention include terpene polymers such as α-pinene, β-pinene, dipentene, and β-phelandrene.

For the polymerization of terpenes, a cationic catalyst such as boron trifluoride or aluminum trichloride is usually used, but any catalyst such as a radical catalyst or a reduction metal catalyst may be used.

The terpene resin used in the present invention has a ring and ball softening point of 60 to 140°C.

In order to exhibit a sufficient effect in improving the transparency of the soft vinyl chloride graft copolymer, 0.00 parts by weight of the terpene resin should be added to 100 parts by weight of the soft vinyl chloride graft copolymer.
It is necessary that the amount is 5 to 50 parts by weight.

If it is less than 0.5 part by weight, the effect of improving transparency is small50
When the amount exceeds parts by weight, flexibility decreases.

The soft vinyl chloride graft copolymer and terpene resin are mixed and/or kneaded to form a uniform resin composition.

The mixing and cross-mixing methods include melt-kneading using a single-screw or twin-screw extruder, kneading using rolls, a Banbury mixer, and the like.

The kneading temperature may be within a range where the resin melts and does not cause decomposition, but the kneading is usually carried out at 100°C or higher and 200°C or lower.

As the kneading time, the time required to obtain a uniformly mixed resin composition may be selected.

The resin according to the present invention can be processed into films, sheets, pipes, hoses, etc. by calendering, extrusion, injection molding, etc. in the same way as conventional soft vinyl chloride graft copolymers.

According to the present invention, transparency, which has conventionally been difficult to improve, can be improved at low cost without substantially reducing other properties.

The soft vinyl chloride graft copolymer of the present invention is particularly useful in fields where transparency and non-migration of plasticizers are required, and its contribution to industry will be significant.

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited in any way.

Examples 1 to 5 Comparative Example 1 Using a 3-inch roll, various amounts of terpene resin were kneaded with a soft vinyl chloride graft copolymer at 130° C. for 10 minutes.

As a soft vinyl chloride graft copolymer, vinyl acetate content is 40% by weight; melt index is 75g/10
A resin obtained by graft polymerizing 40 parts by weight of vinyl chloride heptanomer in the presence of 60 parts by weight of ethylene-vinyl acetate copolymer was used.

As a terpene resin, Picolite S manufactured by PICCO
-100 (β-pinene polymer, ring and ball softening point 100°C
) was used.

As stabilizers for the soft vinyl chloride graft copolymer, 1 part by weight of a dibutyltin laurate stabilizer and 1 part by weight of a dibutyltin maleate stabilizer were used per 100 parts by weight of the resin.

This resin composite was used as a sheet with a thickness of 1 mrIL, and its light transmittance and haze were measured.

The results are shown in Table 1. It can be seen from Table 1 that the soft vinyl chloride graft copolymer blended with a specific proportion of terpene resin is a resin with excellent transparency.

In addition, a resin composite containing 100 parts by weight of a soft vinyl chloride graft copolymer and 100 parts by weight of a terpene resin had reduced flexibility.

Examples 6 to 8 Comparative Example 2 As a soft vinyl chloride graft copolymer, the vinyl acetate content was 32% by weight and the tart index was 30. ! i+/
A resin obtained by graft polymerizing 55 parts by weight of vinyl chloride monomer in the presence of 45 parts by weight of ethylene-vinyl acetate copolymer for 10 minutes was kneaded in the same manner as in Examples 1 to 5. The light transmittance and haze of the resin-composed samurai were measured.

The results are shown in Table 2.

Claims (1)

[Claims] 1 Obtained by polymerizing 30 to 85 parts by weight of a vinyl chloride monomer or a monomer mixture mainly composed of vinyl chloride monomers in the presence of 15 to 70 parts by weight of an ethylene-vinyl acetate copolymer having an ethylene component of 35 to 75% by weight. A resin composition having excellent transparency, which is obtained by blending 0.5 to 50 parts by weight of a terpene resin with 100 parts by weight of a soft vinyl chloride-based graft copolymer.