JPH1160860A - Flexible vinyl chloride resin composition and molded article thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible vinyl chloride resin composition containing a highly polymerized vinyl chloride resin, whose low-temperature molded articles still retain and exhibit mechanical properties which the highly polymerized vinyl chloride resin can impart to its molded articles inherently. SOLUTION: This flexible vinyl chloride resin composition comprises 100 pts.wt. of a vinyl chloride base resin mixture (A) comprising 50-95 pts.wt. of a vinyl chloride homopolymer having an average polymerization degree of 2,000 or more and 5-50 pts.wt. of a copolymer of vinyl chloride with a monomer copolymerizable therewith that has an average polymerization degree of 700-1,500, the average polymerization of the mixture being 2,000-4,000, the content of the monomer copolymerizable with vinyl chloride in the vinyl chloride resin mixture being 0.5-5 wt.% 1-10 pts.wt. of a methyl methacrylate resin (B) having a weight average molecular weight of 3,000,000 or more, and 40-150 pts.wt. of a plasticizer (C).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soft vinyl chloride resin composition which gives a molded article a high elasticity and a molded article thereof. TECHNICAL FIELD The present invention relates to a soft vinyl chloride resin composition that gives high elasticity to articles and a molded article having high elasticity.

[0002]

2. Description of the Related Art A vinyl chloride resin is generally excellent in chemical and physical properties, and a flexible molded product having high flexibility can be easily obtained by blending a plasticizer. , Leather, electric wires, gaskets, etc. Since a normal soft vinyl chloride resin composition uses a vinyl chloride resin with an average degree of polymerization of 1,000 to 1,700, its molded products have low heat resistance and poor rubber properties, so gaskets and vacuum forming sheets There was a problem with using it for such purposes.

[0003] Various methods have been proposed to solve the above problems. As a typical example, a method using a vinyl chloride resin having an average degree of polymerization of 2,000 or more has been proposed, and a composition containing the same has been proposed. Processed products have already been put to practical use in automobile parts, electric wires, hoses, and gaskets of light electric parts as vinyl chloride elastomers.

[0004]

However, the average degree of polymerization is 2,0.
A vinyl chloride resin having a high degree of polymerization of at least 00 has poor moldability, and in order to obtain a soft molded product having mechanical properties such as tensile strength and tensile elongation utilizing the inherent characteristics of the resin, the molding temperature is required to be about The temperature must be 170 ° C. or higher, and there is a drawback that molding is difficult. The drawback that such a soft vinyl chloride resin composition containing a high degree of polymerization vinyl chloride resin is difficult to mold is a factor that hinders the market expansion and development of the high degree of polymerization vinyl chloride resin. Even so, there has been a demand for a soft vinyl chloride-based resin composition containing a high-polymerization degree vinyl chloride resin, which does not impair the mechanical properties of the high-polymerization degree vinyl chloride resin inherent to the molded article.

As a measure against the above problems, an average degree of polymerization of 2,000
It has been proposed to use a vinyl chloride-ethylene copolymer having a high degree of polymerization as described above, and is used for applications requiring low-temperature moldability. Copolymers have limited applications due to their high cost and supply problems. Therefore, there is a demand for a composition composed of raw materials which is still low in cost and easily available.

[0006]

Means for Solving the Problems The present inventors have found that a high degree of polymerization vinyl chloride homopolymer, which is equivalent to the case of using the above high degree of polymerization vinyl chloride-ethylene copolymer, gives an excellent molded product. We studied various soft vinyl chloride resin compositions containing a high polymerization degree vinyl chloride homopolymer that can be molded at low temperatures without impairing the properties such as mechanical properties, excellent heat deformation resistance, and excellent rubber elasticity. Completed the invention.

That is, the present invention relates to (A) 50 to 95 parts by weight of a vinyl chloride homopolymer having an average polymerization degree of 2,000 or more, and an average polymerization degree of 700
Of a vinyl chloride resin mixture comprising 5 to 50 parts by weight of a copolymer of vinyl chloride and a monomer copolymerizable therewith with an average degree of polymerization of 2,000 to 4,000.
Wherein the content of the monomer copolymerizable with vinyl chloride in the vinyl chloride resin mixture is 0.5 to 5% by weight, and 100 parts by weight of the vinyl chloride resin mixture, and (B) the weight average molecular weight is
3,000,000 or more methyl methacrylate resin 1-10
It is a soft vinyl chloride resin composition characterized by comprising 40 parts by weight of a plasticizer (C) and 40 to 150 parts by weight of a plasticizer.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The vinyl chloride homopolymer having an average polymerization degree of 2,000 or more in (A) can be obtained by a commonly used suspension polymerization method. If the average degree of polymerization of this high polymerization degree vinyl chloride homopolymer is less than 2,000, the excellent properties such as mechanical properties, heat deformation resistance, and rubber elasticity that the high polymerization degree vinyl chloride homopolymer originally gives to the molded product are obtained. Not enough. It is preferred to use a high polymerization degree vinyl chloride homopolymer having an average polymerization degree in the range of 2,000 to 6,000. Further, it is particularly preferable to use a high polymerization degree vinyl chloride homopolymer having an average polymerization degree in the range of 2,200 to 4,000. Average degree of polymerization
If it exceeds 6,000, the average degree of polymerization used together with it is 700-
The difference in meltability between 1,500 of vinyl chloride and copolymers of copolymerizable monomers with vinyl chloride increases, the resin melt state during molding tends to be uneven, and the mechanical strength of the resulting molded product May be impaired.

A copolymer of vinyl chloride and a monomer copolymerizable therewith with an average polymerization degree of 700 to 1,500 used in combination with the above-mentioned high polymerization degree vinyl chloride homopolymer will be described. Examples of the monomer copolymerizable with vinyl chloride include vinyl esters such as vinyl acetate and vinyl propionate; methyl acrylate, ethyl acrylate, methyl methacrylate,
(Meth) acrylates such as ethyl methacrylate; olefins such as ethylene and propylene; acrylonitrile; styrene; vinylidene chloride and the like can be used. Among these monomers, in particular, vinyl esters, acrylic esters, methacrylic esters, olefins,
Acrylonitrile, vinylidene chloride and the like are preferred.

The average degree of polymerization of these copolymers is 7
Those in the range of from 00 to 1,500, preferably from 700 to 1,300 are used. If it is less than 700, the difference in the gelation rate for the high polymerization degree vinyl chloride homopolymer becomes large,
At the time of kneading in the molding process, it becomes difficult to uniformly melt the copolymer and the homopolymer of vinyl chloride with a high degree of polymerization, and the resulting molded article is undesirably reduced in mechanical strength. On the other hand, if it exceeds 1,500, the melting point becomes close to that of the vinyl chloride homopolymer having a high degree of polymerization used in combination, the gelation accelerating effect is reduced, and a composition having low-temperature moldability as the object of the present invention cannot be obtained.

The content of the monomer copolymerizable with vinyl chloride contained in the copolymer used in the present invention is preferably 3 to 20% by weight. If the content of the monomer is not in this range, the uniform meltability with the vinyl chloride homopolymer having a high degree of polymerization at the time of kneading during the molding process is reduced.
The mixing ratio (weight ratio) of the vinyl chloride homopolymer having an average degree of polymerization of 2,000 or more and the copolymer of vinyl chloride and a monomer copolymerizable therewith with an average degree of polymerization of 700 to 1,500 is 95: 5.
50:50 is required, preferably 93: 7 to 75:25. If the mixing ratio of the above vinyl chloride homopolymer exceeds 95, the desired effect at low temperature molding cannot be obtained. When the mixing ratio is less than 50, the mechanical strength, heat deformation resistance, and rubber elasticity equivalent to those possessed by the molded article of the high polymerization degree vinyl chloride homopolymer are impaired, or the inner wall of the molding machine during molding is deteriorated. This is not preferable because the adhesion of the resin to the resin increases.

The average degree of polymerization of (A) needs to be 2,000 to 4,000, preferably 2,100 to 3,000. If the average degree of polymerization is less than 2,000, the molded article obtained has a high degree of polymerization of vinyl chloride alone. Excellent properties such as mechanical properties, heat deformation resistance, and rubber elasticity, which are equivalent to the properties of a polymer molded article, are impaired. If it exceeds 4,000, the low-temperature moldability as an effect of the present invention cannot be sufficiently obtained. Further, it is essential that the content of the monomer copolymerizable with vinyl chloride in (A) in the vinyl chloride resin mixture is in the range of 0.5 to 5% by weight, and if this is less than 0.5% by weight. If the low-temperature moldability, which is a feature of the present invention, cannot be sufficiently obtained, and if the content exceeds 5% by weight, the resin adheres to the inner wall of the molding machine or the initial coloring property of the obtained molded product is deteriorated. However, it is not preferable because the cost is high.

In the present invention, the weight average molecular weight of (B) is
Methyl methacrylate-based resin of 3,000,000 or more has the effect of promoting the gelation and melting of the vinyl chloride-based resin mixture of the above (A) during kneading during molding, and has the effect of keeping the viscosity of the molten resin high. And it is used for improving secondary workability such as vacuum forming. The weight average molecular weight of the methyl methacrylate resin used in the present invention is
It is essential that it is at least 3,000,000, and if it is less than 3,000,000, sufficient low-temperature moldability, which is the effect of the present invention, cannot be obtained, and the effect of improving the secondary workability will also be insufficient.

As the methyl methacrylate resin (B) in the present invention, polymethyl methacrylate, methyl methacrylate and copolymers of monomers copolymerizable therewith can be used. Here, the monomer copolymerizable with methyl methacrylate having a methyl methacrylate content of more than 50% by weight and preferably more than 70% by weight includes, for example, methyl acrylate, ethyl acrylate, acryl Examples thereof include alkyl acrylates such as butyl acrylate, and styrene. In the present invention, (B) is added in an amount of 1 to 10 parts by weight based on 100 parts by weight of (A). If the amount is less than 1 part by weight, sufficient low-temperature processability cannot be obtained. Mechanical properties such as tensile strength and tensile elongation decrease. On the other hand, if the amount exceeds 10 parts by weight, a sufficient effect of improving the mechanical properties cannot be obtained, resulting in an inconvenience such as an increase in material cost.

In the present invention, the plasticizer (C) includes
As long as it is conventionally used for soft molding of a vinyl chloride resin, any of them can be used without any particular limitation. For example, phthalic acid ester, trimellitic acid ester, aliphatic 2
In addition to basic acid esters, glycol esters, phosphoric acid esters, epoxy plasticizers and polyester plasticizers, E
Polymer plasticizers such as VA, NBR and urethane are exemplified. These may be used in combination of two or more as necessary. (C) requires 40 to 150 parts by weight based on 100 parts by weight of (A). If the addition amount is less than 40 parts by weight, the hardness of the obtained molded product is increased and a soft molded product cannot be obtained,
If the amount exceeds 150 parts by weight, the obtained molded product becomes too soft, resulting in a decrease in mechanical strength and lacks practicality as a flexible molded product.

In the composition of the present invention, an ethylene copolymer having a melting point of 160 ° C. or less, preferably 80 to 150 ° C. or less, is further added in an amount of 0.2 to 5 parts by weight based on 100 parts by weight of (A). The effect of promoting gelation is further exhibited, and the low-temperature moldability, which is the object of the present invention, can be greatly improved. Examples of the ethylene-based copolymer include partially oxidized polyethylene, copolymers of ethylene and styrene, methyl methacrylate, acrylic acid, acrylonitrile, and vinyl acetate, among which partially oxidized polyethylene, ethylene and It is preferable to use a copolymer of acrylic acid and a copolymer of ethylene and vinyl acetate. The melting point is measured according to ASTM-3104.

In the present invention, in addition to these, a heat stabilizer, a lubricant, a flame retardant, a filler, a foaming agent, a pigment and the like which are usually used as additives of a vinyl chloride resin can be blended as required. . Examples of the heat stabilizer include lead-based stabilizers such as tribasic lead sulfate; tin-based stabilizers such as dibutyltin mercaptan; metal soaps such as calcium stearate, barium stearate, and zinc stearate, and complexes thereof. . As the lubricant, low molecular weight polyethylene, various kinds of metal soaps, higher fatty acid esters and the like are used. Examples of the flame retardant include antimony oxide and brominated polymer flame retardants. As the filler, an appropriate amount can be used, such as calcium carbonate, talc, clay, and the like, granules, scales, needles, and fibers. Examples of the foaming agent include organic foaming agents such as azodicarbonamide and benzenesulfonic acid hydrazide, and foaming agents such as baking soda.Examples of the pigment include inorganic pigments such as titanium oxide and red iron oxide, and organic pigments such as phthalocyanine bull and polyazo red. Are also exemplified. Further, in the present invention, if necessary, polyurethane, ABS, A
Various elastomers such as S, MBS and chlorinated polyethylene may be used in combination.

In order to knead and melt the composition of the present invention, a kneader such as an open roll, a Banbury mixer, a single screw extruder, or a twin screw extruder can be used as in the case of kneading a normal soft vinyl chloride resin. The kneading of the composition of the present invention can exert the above-mentioned effects even at a temperature lower by 10 to 20 ° C. than that of a vinyl chloride homopolymer having the same degree of polymerization, and has a wide range of kneading conditions. In molding the composition of the present invention, extrusion molding, injection molding, calender molding, pressure molding and the like can be applied, and the resulting molded article has creep resistance, excellent mechanical strength at high temperatures, and excellent rubber properties. doing. For example, in the case of extrusion molding, various gaskets and hoses for automobiles, light electric appliances and buildings; in the case of injection molding, various packings and boots; in calendar molding, sheets for vacuum molding of automobiles; In this case, it is suitably used for a wide range of applications such as various mats.

[0019]

Next, the present invention will be described with reference to examples. (Examples 1 to 6, Comparative Examples 1 to 9 and Reference Example 1) Various raw material resins and the like shown in Tables 1 to 3 were charged into a Henschel mixer at a mixing ratio (all parts by weight) shown in Tables 1 to 3 and stirred. , 110 ℃
After raising the temperature to 40 ° C., a powdery compound was obtained. .

(Evaluation of roll processability) The compound obtained above was put into a 6-inch roll whose surface temperature was set to 150 ° C. in advance and kneaded, and the compound was wound around a roll (minute). Was measured and further wound on a roll, and kneaded with a roll for 5 minutes to obtain a roll sheet having a thickness of 0.8 mm. The kneading state of the roll bank molten resin at this time was observed, and the kneading property was evaluated based on the following criteria.

Evaluation criteria for kneading state (roll kneading property) of molten resin A: Roll bank molten resin rotates uniformly, and the molten state is good. ：: The roll bank molten resin rotated almost uniformly, and the molten state was almost good. Δ: The roll bank molten resin rotated slightly unevenly, and the molten state was hard. X: The state in which the roll bank molten resin rotated unevenly and was extremely melted.

(Evaluation of Gelling Property) The gelling time (min) of the powdery compound obtained above was measured under the following test conditions using a blast graph manufactured by Brabender. Gelling test conditions Jacket temperature: 180 ° C Rotational speed: 40 rpm Filling amount: 55 g Kneader capacity: 50 cc

(Evaluation of fluidity) Using the roll sheet obtained above, a Koka type flow tester (manufactured by Shimadzu Corporation)
Was measured at 170 ° C. under a load of 50 kg (mm ³ / sec).

(Measurement of Compression Set) The roll sheet obtained above was cut, press-formed at 160 ° C. and 29 mmφ × 1
A tablet having a compression set of 2.7 mm was prepared, and the compression set was measured using the tablet according to JIS K-6301.

(Tensile test) The compound obtained above is put into a 6-inch roll whose surface temperature is set to 180 ° C. in advance and kneaded, and after kneading the compound around the roll, it is further kneaded for 5 minutes. Thus, a roll sheet having a thickness of 0.8 mm was produced. The obtained roll sheet was cut and press-formed at 190 ° C. to produce a sheet having a thickness of 1 mm. Using this press sheet, a tensile test was performed in accordance with JIS K-6723 (this is referred to as a 180 ° C. roll sheet tensile test). The 150 ° C kneaded roll sheet obtained above was cut and press-formed at 160 ° C to produce a roll sheet having a thickness of 1 mm. Using this roll sheet, a tensile test was performed according to JIS K-6723 (this is referred to as a 150 ° C. roll sheet tensile test).

Manufacturers of various raw materials used in the examples
The product names and standards are shown below. TK-2500P Shin-Etsu Chemical Co., Ltd. vinyl chloride homopolymer, degree of polymerization 3,000, TK-2500HS Shin-Etsu Chemical Co., Ltd. vinyl chloride homopolymer, polymerization degree 2,450, TK-1700 Shin-Etsu Chemical Co., Ltd. Vinyl chloride homopolymer, polymerization degree 1,700, TK-1300 Shin-Etsu Chemical Co., Ltd. vinyl chloride homopolymer, polymerization degree 1,300, MA-800S Shin-Etsu Chemical Co., Ltd. vinyl chloride-vinyl acetate copolymer, polymerization 800 (containing 7% by weight of vinyl acetate), SB-500 Vinyl chloride-vinyl acetate copolymer manufactured by Shin-Etsu Chemical Co., Ltd., polymerization degree 500 (containing 10% by weight of vinyl acetate), VE-L Sekisui Chemical Co., Ltd. ) Vinyl chloride-ethylene copolymer, degree of polymerization 1,300 (containing 4% by weight of ethylene), E-2800 Tosoh Corporation vinyl chloride-ethylene copolymer, degree of polymerization 2,800 (containing 1% by weight of ethylene), metaprene P -551 Mitsubishi Re Yeon Co., Ltd. methyl methacrylate resin, weight average molecular weight 1.45 million (contains 70% by weight of methyl methacrylate), metaprene P-531 Mitsubishi Rayon Co., Ltd. methyl methacrylate resin, polymerization degree 4.7 million (methyl methacrylate) AC-6A Allied Care Chemical, polyethylene, melting point 106 ° C (low molecular weight polyethylene), AC-316A Allied Chemical Co., partially oxidized polyethylene, (oxidized 40 mg KOH / g, low molecular weight ethylene copolymer) AC-400A Allied Chemical Co. ethylene vinyl acetate copolymer (vinyl acetate content 13%, melting point 95 ° C, low molecular weight ethylene copolymer), AC-540A Allied Chemical Co. ethylene acrylic acid copolymer , (Oxidized 40 mg KOH / g, melting point 108 ° C, low molecular weight ethylene copolymer).

[0027]

[Table 1]

[0028]

[Table 2]

[0029]

[Table 3]

(Evaluation of Vacuum Formability) Using the powdery compounds obtained in Examples 1 to 6, Comparative Examples 1 to 9 and Reference Example 1, the thickness obtained by calendering at a roll surface temperature of 150 ° C. 1.2mm calendar sheet 70cm x 70cm
To prepare a sheet for vacuum forming. Using this vacuum forming sheet, the sheet was preheated to a temperature of 150 ° C. and vacuum formed to produce a 1.0 mm thick vacuum formed sheet. The obtained vacuum formed sheet was evaluated according to the following criteria. ◎: Good and uniform thickness. ：: Molded to a substantially uniform thickness. Δ: malleability (elongation) was poor as a whole, and a part of the corner was formed into an uneven thickness. ×: The malleability (elongation) is poor as a whole, and the corners are formed to have an uneven thickness.

[0031]

The composition of the present invention exhibits excellent processability,
In particular, it has excellent physical properties during low-temperature processing, and can obtain molded products with excellent smoothness and dimensional accuracy under a wide range of processing conditions during extrusion molding, and thin-wall large-formed products due to its excellent fluidity during injection molding. It can be easily obtained, and it can be processed at high speed under a wide range of processing conditions due to its excellent gelling property at the time of calendering. In addition, a molded product with a uniform thickness can be obtained even in secondary processing such as vacuum forming. Can be easily obtained.

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[Procedure amendment]

[Submission date] December 12, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction contents]

Manufacturers of various raw materials used in the examples
The product names and standards are shown below.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Ryozo Tanizawa 1 Towada, Kazu-gun, Kashima-gun, Ibaraki Pref. Shin-Etsu Chemical Co., Ltd.

Claims (3)

[Claims] (A) 50 to 95 parts by weight of a vinyl chloride homopolymer having an average polymerization degree of 2,000 or more, and an average polymerization degree of 700 to 1,500.
In a vinyl chloride resin mixture comprising 5 to 50 parts by weight of a copolymer of vinyl chloride and a monomer copolymerizable therewith, the average degree of polymerization of the mixture is 2,000 to 4,000,
100 parts by weight of a vinyl chloride resin mixture in which the content of the monomer copolymerizable with vinyl chloride in the vinyl chloride resin mixture is 0.5 to 5% by weight, and (B) the weight average molecular weight is 3,000,000 or more. 1 to 10 parts by weight of a certain methyl methacrylate resin,
(C) Plasticizer
A soft vinyl chloride resin composition comprising 40 to 150 parts by weight. 2. A melting point of 160 parts by weight with respect to 100 parts by weight of (A).
2. The soft vinyl chloride resin composition according to claim 1, which contains 0.2 to 5 parts by weight of an ethylene copolymer having a temperature of not more than 0.degree. 3. A soft vinyl chloride resin molded product obtained by molding the soft vinyl chloride resin composition according to claim 1 or 2.