JP2940634B2 - Manufacturing method of molded products with excellent impact resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention has excellent quality by blending a saponified ethylene-vinyl acetate copolymer with an ethylene-propylene copolymer elastomer and melt-molding. The present invention relates to a method for producing a molded product.

[Prior art] Saponified ethylene-vinyl acetate copolymer is remarkably superior to other molding resins in terms of rigidity, hardness, abrasion resistance, antistatic property and the like. Is not enough.

As a countermeasure, it is known that a synthetic rubber such as a styrene-butadiene copolymer and an acrylonitrile-butadiene copolymer, a polyester elastomer, a thermoplastic urethane resin, and an ethylene copolymer are blended.

[Problems to be Solved by the Invention] However, when synthetic rubber is used, thermal decomposition occurs at the time of molding, or the weather resistance of the molded product is insufficient. In the case of polyester elastomer, the chemical resistance of the molded product becomes a problem or the impact resistance is reduced. The effect of improving the properties is not always sufficient.

Furthermore, in the case of thermoplastic urethane, there are drawbacks such as remarkable thickening at the time of molding, and in the case of ethylene copolymer, long-run moldability is insufficient, and the conventional method cannot sufficiently improve the impact resistance. That is the fact.

[Means for Solving the Problems] The inventors of the present invention have conducted intensive studies in order to solve such problems, and as a result, (A) saponified ethylene-vinyl acetate copolymer,
(B) a graft polymer obtained by subjecting an ethylene-propylene copolymer elastomer and (C) a polyolefin resin to a graft reaction of an ethylenically unsaturated carboxylic acid or a derivative thereof, and further reacting a polyamide; and (A)
(C) is 50 to 99.5% by weight, 0.4 to 5
It has been found that the object can be achieved when a composition of 0% by weight and 0.1 to 15% by weight is melt-molded, and the present invention has been completed.

The saponified ethylene-vinyl acetate copolymer (A) targeted in the present invention has an ethylene content of 20 to 60 mol%, preferably
25 to 55 mol%, with a degree of saponification of the vinyl acetate component of 95 mol% or more.

If the ethylene content is less than 20 mol%, the water resistance is reduced, while if it is more than 60 mol%, physical properties such as rigidity and wear resistance are reduced. If the saponification degree is 95 mol% or less, rigidity, hardness and water resistance are reduced.

Further, the saponified copolymer may further contain a small amount of α-olefin such as propylene, isobutene, α-octene, α-dodecene, α-octadecene, unsaturated carboxylic acid or its salt, partial alkyl ester, complete alkyl ester, nitrile. , Amides, anhydrides, or unsaturated sulfonic acids or salts thereof, as co-monomers.

(B) The ethylene-propylene copolymer elastomer is a copolymer elastomer having an ethylene composition of 30 to 90% by weight, a density of about 0.85 to 0.87 g / cm ³ and a glass transition temperature of -50 to -60 ° C. Is often used.

It is also possible to use a terpolymer obtained by copolymerizing a diene monomer as a third component other than ethylene and propylene.

In the present invention, in order to improve the compatibility between (A) and (B), it is necessary to add (C).

(C) is a graft polymer obtained by subjecting a polyolefin resin to a graft reaction with an ethylenically unsaturated carboxylic acid or a derivative thereof, and further reacting the carboxylic acid or a derivative thereof with a polyamide.

The graft polymer is obtained by dissolving or suspending a polyolefin-based resin in a suitable solvent, or in a molten state, activating a polyolefin-based resin chain with a peroxide or a diazo-based initiator to form an ethylenically unsaturated carboxylic acid. Alternatively, it is produced by graft-reacting a derivative thereof to obtain a polymer, and mixing the polymer and polyamide in a molten state.

Brabender, bath blender,
Single screw extruder, Werner and Friedler type 2
A screw extruder or the like is used.

The degree of polymerization of the polyolefin resin used is 350-450
A value of 0, preferably about 500 to 1000 is selected. The melt flow rate (230 ° C, load 2160g, the same applies hereinafter) is 0.
About 1 to 50 g / 10 minutes is practical.

The reaction ratio between the polyolefin resin and the ethylenically unsaturated carboxylic acid (or a derivative thereof) is 100/0 in terms of weight ratio.
It is from 05 to 100/10, preferably from 100 / 0.05 to 100/3.

Below 100 / 0.05, the compatibility improvement effect becomes insufficient and
If it is 10 or more, the viscosity at the time of molding becomes large and the practicality is poor.

Further, the degree of polymerization of the polyamide oligomer is practically 80 to 1000, preferably about 100 to 500, and the reaction ratio is 0.01 to 1 mol per carboxyl group, preferably 0.5 to 0.9.
Molar is preferred.

Examples of the polyolefin resin in the above include linear bottom density polyethylene / medium density / high density polyethylene, ionomer, ethylene-propylene copolymer, ethylene-
Acrylic ester copolymers, ethylene-vinyl acetate copolymers and the like can be mentioned. In particular, linear low-density polyethylene, low-density polyethylene, ethylene-propylene copolymer, and ethylene-vinyl acetate copolymer are practically important.

The ethylenically unsaturated carboxylic acid or its derivative to be grafted to the backbone polymer is an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, or an anhydride, a half ester thereof, or the like. Say.

The polyamide is produced by a known method such as polyaddition of lactam, polycondensation of aminocarboxylic acid, and polycondensation of diamine and dicarboxylic acid.

Specific examples of the polyamide raw materials include lactams such as ε-caprolactam, enantholactam, caprylactam, lauryl lactam, α-pyrrolidone, α-piperidone, 6-aminocaproic acid, 7-aminoheptanoic acid, and 9-aminononanoic acid. Ω-amino acids such as, 11-aminoundecanoic acid, adipic acid, glutaric acid, pimelic acid, speric acid, azelaic acid, sebacic acid, undecandionic acid, dodecadionic acid, hexadecadionic acid, hexadecenedionic acid, eicosan Dibasic acids such as diacid, eicosadienedioic acid, diglycolic acid, 2,2,4-trimethyladipic acid, xylylenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, hexamethylene Diamine, tetramethylenediamine, nonametyl Diamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4 (or 2,4,4) -trimethylhexamethylenediamine, bis- (4,4'-aminocyclohexyl) methane, metaxylylenediamine Diamines and the like. Monoamines such as laurylamine and oleylamine can also be used as appropriate for the purpose of controlling the molecular weight.

In the composition of the present invention, the mixing ratio of (A), (B) and (C) is (A) 50 to 99.5% by weight, preferably 60 to 95% by weight, and (B) is 0.4 to 50% by weight, preferably 4.5-35% by weight, (C) should be 0.1-15% by weight, preferably 0.5-10% by weight.

When (A) is 50% by weight or less or (B) is 50% by weight or more, rigidity, hardness and abrasion resistance are lowered, while (A) is 99.5%.
If it is not less than 0.4% by weight or (B) is not more than 0.4% by weight, the effect of improving impact resistance will be insufficient. On the other hand, if (C) is 0.1% by weight or less, the effect of improving impact resistance is poor due to poor compatibility between (A) and (B), and if it is 15% by weight or more, long-run moldability deteriorates, which is disadvantageous.

The composition is directly used for molding, or once mixed pellets are prepared and then used for molding.

The melt molding method is not particularly limited, and any of an injection molding method, an extrusion molding method, a compression molding method, a rotational molding method, a blow molding method, a fluid immersion method, and the like are employed.

The temperature of the molten resin at the time of molding is suitably about 170 to 260 ° C. so that the resin maintains an appropriate fluidity and avoids thermal decomposition. In the molding, a known additive such as a stabilizer, plasticity, a filler, a coloring agent, a foaming agent, a skeleton, or a reinforcing material such as glass fiber or carbon fiber may be added to the resin mixture as needed.

The molded product obtained by the above-mentioned method can be used for various uses such as general machine parts, automobile / marine / aircraft parts, optical clock equipment parts, electric equipment parts and the like.

In addition to such uses, the molded product of the present invention is also useful as a packaging material for sheets, films, bottles and the like.

In this application, the saponified ethylene-vinyl acetate copolymer exhibits oxygen barrier properties as a characteristic property.

In such applications, the molded article of the present invention is not only used as a single layer, but is often used by being laminated with various thermoplastic resins such as polyolefin, polyester, and nylon. The molded article is subjected to a uniaxial or biaxial stretching treatment as necessary, and is put to practical use.

[Action] In the present invention, the impact resistance of the saponified ethylene-vinyl acetate copolymer (A) is significantly improved by the polymerization of the ethylene-propylene copolymer elastomer (B) and the specific graft polymer (C).

[Example] Next, the molded product of the present invention will be described more specifically with reference to examples. Hereinafter, “parts” or “%” are expressed on a weight basis unless otherwise specified.

Sample preparation Examples 1 to 10 and Control Examples 1 to 2 The compositions of (A), (B) and (C) were mixed well in powder form with a Hensiel mixer and then dried in a hot air drier.
This powder was then fed to an injection molding machine with an injection volume of 3.5 ounces, nozzle temperature 220 ° C, front temperature 200 ° C, rear temperature 220 ° C.
Injection molding was performed under molding conditions of 35 ° C., a mold temperature, an injection pressure of 1200 kg / cm ² , and a cycle of 35 seconds to prepare a test piece.

 The physical properties of the test piece thus obtained were measured.

 The results are shown in Table 1.

[Effects] The composition produced from the composition comprising (A), (B), and (C) of the present invention shows the molding processability and appearance of the molded product of the saponified ethylene-vinyl acetate copolymer. The impact resistance is greatly improved without any loss.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI (C08L 29/04 23:16 87:00)

Claims (1)

(57) [Claims] 1. A graft reaction of (A) a saponified ethylene-vinyl acetate copolymer with (B) an ethylene-propylene copolymer elastomer and (C) a polyolefin resin with an ethylenically unsaturated carboxylic acid or a derivative thereof. , Further blending a graft polymer obtained by reacting polyamide,
And molding having excellent impact resistance, characterized by melt-molding a composition in which the proportions of (A) to (C) are 50 to 99.5% by weight, 0.4 to 50% by weight, and 0.1 to 15% by weight, respectively. Manufacturing method of goods.