JP2001002855A - Resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition which is flexible and shows excellence in strength, fabricability, heat resistance, heat aging resistance and the like. SOLUTION: This composition comprises 20 to 60 pts.wt. of an ethylene- unsaturated ester copolymer (A), 10 to 40 pts.wt. of polypropylene (B) and 10 to 40 pts.wt. of a styrene-based elastomer (C). The composition preferably has strength at break of 5 to 30 Mpa, bending stiffness of 50 to 170 Mpa and heat resistance at a temperature of not less than 120 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a resin composition which is flexible and has excellent strength, workability, heat resistance, heat aging resistance and the like.

[0002]

2. Description of the Related Art An ethylene / unsaturated ester copolymer containing an unsaturated ester component in a considerable amount is excellent in flexibility, processability, impact resistance, weather resistance, filler loading property and the like, and is used as a molding material. Widely used. However, since the melting point is low and the strength and elongation are remarkably reduced in a high-temperature atmosphere, it cannot be used as it is in a field where heat resistance is required.

[0003] As a means for improving the heat resistance of the above ethylene copolymer, there is a method of crosslinking the copolymer, but in many cases, its workability is impaired, and thus its application field has been limited. As another method for improving heat resistance, a method of blending a thermoplastic polymer having a high melting point or softening point can be considered. However, in a normal case, if the blending ratio is small, no significant improvement was observed. Although the heat resistance is improved by increasing the blending amount, thermoplastic polymers having a high melting point or softening point are generally hard, and thus sacrificing the flexibility characteristic of the ethylene copolymer. There were many things.

[0004] For example, when blending polypropylene, which is a high melting point polymer, with an ethylene / unsaturated ester copolymer, the heat resistance is considerably improved by blending the polypropylene, but the composition is such that it can withstand a high temperature of 120 ° C or more. In order to obtain the product, a considerable amount of polypropylene had to be blended. As a result, the flexibility is impaired, and only a composition having a small elongation can be obtained due to the lack of compatibility between the two, resulting in a disadvantage that the composition is not suitable as a molding material.

[0005]

In view of the above situation, the present inventor has developed a formulation that effectively improves heat resistance while taking advantage of the excellent flexibility and processability of an ethylene / unsaturated ester copolymer. Study was carried out. As a result, they have found that a composition having desired physical properties can be obtained when an appropriate amount of a styrene-based elastomer is blended with polypropylene. Accordingly, an object of the present invention is to provide a resin composition having high strength and elongation, and having excellent heat resistance, flexibility, workability, and the like.

[0006]

According to the present invention, an ethylene / unsaturated ester copolymer (A) is 20 to 60 parts by weight, a polypropylene (B) is 10 to 40 parts by weight, and a styrene elastomer (C) is 10 to 40 parts by weight. And a resin composition comprising:

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The ethylene / unsaturated ester copolymer (A) may be used alone or in combination of two or more. The copolymer has an average unsaturated ester content of 10 to 49% by weight. %, Preferably 15 to 46% by weight. Therefore, when used in combination of two or more, the unsaturated ester content is 5 to 4
Any combination of two or more of 9% by weight, preferably 10 to 46% by weight may be used so as to have the above average unsaturated ester content. If the content of the unsaturated ester is less than the above range, it is not preferable because it hardly contributes to imparting flexibility and processability. If the content is too large, the composition becomes sticky, which is not preferable.

The ethylene / unsaturated ester copolymer also has a melt flow rate of 0.1 to 50 g / 10
It is desirable to use a composition having a heat resistance of 0.1 to 15 g / 10 minutes in order to obtain a composition having good heat resistance.

Examples of the unsaturated ester in the ethylene / unsaturated ester copolymer include vinyl esters such as vinyl acetate, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, n-butyl acrylate, and isooctyl acrylate. And unsaturated carboxylic esters such as methyl methacrylate. Such an ethylene / unsaturated ester copolymer can be produced by radical copolymerization under high temperature and high pressure, similarly to the production of high pressure polyethylene.

The polypropylene (B) used in the present invention
Is isotactic polypropylene or syndiotactic polypropylene, and may be not only a propylene homopolymer but also a copolymer of propylene and a small amount of one or more other olefins. Other olefins in the copolymer include ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene and the like. The copolymer may also be a random copolymer or a block copolymer.

As the polypropylene, it is desirable to use a copolymer in consideration of the compatibility with other components, and the melting point is 155 ° C. or more to impart sufficient heat resistance.
In particular, it is desirable to use one having a temperature of 160 ° C. or higher. Further, in order to obtain a composition having excellent workability, strength and heat resistance, the melt flow rate at 230 ° C. and a load of 2160 g is 0.1 to 100 g / 10 min, especially 0.5 to 50 g.
It is preferable to use one with g / 10 minutes.

In the present invention, a styrene elastomer (C) is used together with the ethylene / unsaturated ester copolymer (A) and the polypropylene (B). As the styrene-based elastomer, one having as few olefinic double bonds as possible is desirable. For example, an ABA type block copolymer is optimal. Here, A is a styrene polymer block, and B is an alkylene copolymer block, specifically, an ethylene / butene copolymer block or an ethylene / propylene copolymer block. Such a block copolymer is a styrene-butadiene-styrene block copolymer generally called SBS or a styrene-isoprene-styrene block copolymer butadiene polymer block or isoprene polymer called SIS. It is obtained by hydrogenating a block and is generally called SEBS or SEPS. Here, the styrene polymer block content is 8 to 50% by weight, especially 10 to 40% by weight.
The melt flow rate at 230 ° C. and a load of 2160 g is preferably 0.1 to 100 g / 10 min.
In particular, it is preferable to use one of about 0.5 to 50 g / 10 minutes.

When the total amount of the ethylene / unsaturated ester copolymer (A), the polypropylene (B) and the styrene-based elastomer (C) is 100 parts by weight, (A) is 20 to 60 parts by weight, preferably 30 to 55 parts by weight, (B) 10 to 40 parts by weight, preferably 20 to 35 parts by weight, (C) 10 to 40 parts by weight,
Preferably it is in the range of 15 to 35 parts by weight. ethylene·
If the proportion of the unsaturated ester copolymer is more than the above range and the proportion of the polypropylene is less than the above range, a composition having excellent heat resistance will not be obtained, and conversely, the ethylene / unsaturated ester copolymer will not be obtained. When the use ratio of the coalesce is less than the above range and the use ratio of polypropylene exceeds the above range, a composition having excellent flexibility cannot be obtained.
If the proportion of the styrene-based elastomer is less than the above range, a composition having excellent heat aging resistance cannot be obtained. When the amount exceeds the above range, a composition having excellent tensile properties cannot be obtained.

The composition of the present invention may be used in combination with a petroleum softener such as a paraffinic process oil or a naphthenic oil, or a silicone oil. The composition of the present invention may contain various additives as necessary.
Examples of such additives include antioxidants, heat stabilizers,
Light stabilizers, ultraviolet absorbers, antistatic agents, lubricants, antiblocking agents, pigments, dyes, crosslinking agents, crosslinking aids, foaming agents,
Examples include foaming aids, plasticizers, oils, inorganic fillers, organic or inorganic flame retardants, and reinforcing fibers.

In order to obtain the ethylene copolymer composition of the present invention, the components (A), (B), (C) and various additives as optional components are mixed with a usual kneading apparatus, for example, a screw extruder, Using a pressure kneader, Banbury mixer, etc.
What is necessary is just to melt-knead at about 60-200 degreeC.

[0016]

Next, the present invention will be described in more detail by way of examples. In addition, the raw materials and various physical property evaluation methods used in the examples are as follows. 1. Raw material (A) Ethylene / unsaturated ester copolymer EVA: Ethylene / vinyl acetate copolymer (vinyl acetate content 28% by weight, melt flow rate 4 g / 10 min (19
(B) Polypropylene PP: Propylene-ethylene copolymer (melt flow rate 5 g / 10 min (230 ° C, 2160 g load), melting point 163 ° C) (C) Styrene-based elastomer PS-1: Styre PS-2: styrene-ethylene / propylene-styrene triblock copolymer (styrene content 29% by weight, melt flow rate 1 g / 10 minutes (230 ° C., 2160 g load)) Styrene content 13% by weight, melt flow rate 7 g / 10 min (230 ° C., 2160 g load)) (D) Antioxidant Ir1010 (Irganox 1010, manufactured by Ciba Specialty Chemicals)

2. Physical property test method (1) Tensile properties: in accordance with JIS K6760 Specimen: JIS K6301 No. 3 dumbbell 1 mm thick Heat aging is based on JIS C3001 heating conditions (120
(2 hours) Flexural rigidity: JIS K7106

Examples 1 to 3 and Comparative Examples 1 to 3 Each raw material was blended at the blending ratio shown in Table 1 and melt-kneaded with a 40 mmφ single screw extruder to prepare a polymer composition. Then, a sheet having a thickness of 1 mm was prepared by press molding, and the physical properties were evaluated. The results are also shown in Table 1.

[0019]

[Table 1]

[0020]

The resin composition of the present invention has excellent tensile properties, flexibility, heat resistance, heat aging resistance and moldability. For example, by appropriately selecting the type and blending ratio of the raw materials,
The composition has a breaking point strength of 5 to 30 MPa, an elongation of 150% or more, a flexural rigidity of 50 to 170 MPa, does not melt even in a heat aging test at 120 ° C., and can maintain a high strength. Taking advantage of such properties, extrusion molding,
Various molded articles can be used by molding methods such as injection molding, hollow molding, compression molding, foam molding, and vacuum molding. For example, civil engineering fields such as artificial turf, mats, tunnel sheets, waterproof sheets, roofing, etc., pipe applications such as hoses and tubes, home appliances such as packing and vibration damping sheets, carpet backing materials, door panel waterproof sheets, mudguards In various fields, such as interior and exterior parts of malls, building materials such as furniture, flooring materials, foam sheets, etc., communication cables containing flame retardants, power cables, household appliances cords, wiring in equipment, and cable applications such as shrink tubing. Can be used.
Further, the resin composition of the present invention can be widely used as a base resin for non-halogen flame retardant materials.

Claims (2)

[Claims] 1. An ethylene / unsaturated ester copolymer (A) of 20 to 60 parts by weight and a polypropylene (B) of 10 to 10 parts by weight.
40 parts by weight and styrene elastomer (C) 10-4
A resin composition comprising 0 parts by weight. 2. The resin composition according to claim 1, wherein the resin composition has a breaking point strength of 5 to 30 MPa, a flexural rigidity of 50 to 170 MPa, and a heat resistance of 120 ° C. or higher.