JP3312909B2 - Vinyl chloride resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention has excellent heat resistance, impact resistance, and moldability, so that it can be used for roofing materials, sizing materials, electric equipment parts, automobile parts, and pipe materials. The present invention relates to a vinyl chloride resin composition useful as a raw material for molding pipes, pipe joints, hoses and the like.

[Prior Art] Vinyl chloride resins are widely used as various molding materials and film materials because they have excellent physical and chemical properties and are very inexpensive. However, on the other hand, there is a drawback in that the heat resistance and moldability of the molded product are poor, so that there is a problem that it cannot sufficiently cope with diversification of uses.

Therefore, the following method has been proposed as a means for improving these disadvantages.

That is, as a means for improving the insufficient heat resistance, there is a method of chlorinating a vinyl chloride resin. The heat resistance of the chlorinated vinyl chloride resin obtained by this method is considerably improved as compared with the conventional vinyl chloride resin, but it is not always sufficient, whereas the moldability due to chlorination is rather deteriorated. Because of the tendency, applications are severely limited.

Therefore, when using a chlorinated vinyl chloride resin as a base resin, a large amount of processing aids must be blended, and in some cases, a considerable amount of unchlorinated vinyl chloride resin must be blended. Therefore, the excellent heat resistance of the chlorinated vinyl chloride resin cannot be effectively utilized.

As another method for improving the heat resistance of a vinyl chloride resin, a method of blending a heat-resistant copolymer using a maleimide compound having a specific structure has been developed (Japanese Patent Publication No. Sho 63 (1988)).
No. 57460, JP-A Nos. 62-240344, 61-264037, 6
No. 3-46249). However, in these methods, although the heat resistance is improved, the disadvantage that the impact resistance is significantly reduced is unavoidable, and after all, all of the heat resistance, the impact resistance, and the moldability cannot be satisfied.

Also, a modifier using a copolymer obtained by copolymerizing N-substituted maleimide with α-methylstyrene or the like as a modifier for a vinyl chloride resin is known (JP-A Nos. 62-34938 and 61-34938).
-1443459). However, these modifiers have a relatively small ratio of the N-substituted maleimide monomer in the entire modifier and are used as one component of a polymer alloy composed of a vinyl chloride resin / ABS resin. Only. Further, since the content of the maleimide-based monomer is small, the compatibility with the vinyl chloride-based resin is poor, and particularly, the effect of improving impact resistance is not effectively exhibited.

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned circumstances, and its object is to maintain heat resistance while maintaining the inherent characteristics of a vinyl chloride resin. It is an object of the present invention to establish a technology capable of improving both impact resistance and molding workability.

[Means for Solving the Problems] The vinyl chloride resin composition according to the present invention, which can solve the above problems, comprises: [I] a vinyl chloride polymer, and [II] styrene: 20 to 68% by weight. , N-substituted maleimide monomer: 30 to 60% by weight, and unsaturated nitrile monomer: 2
It has a gist in that it contains a copolymer consisting of up to 40% by weight (100% by weight in total).

[Action] The base resin used in the present invention is a vinyl chloride-based polymer [I]. In addition to a homopolymer of vinyl chloride, a copolymer containing vinyl chloride as a main polymerization component, and further a chlorinated polymer thereof A chlorinated vinyl chloride polymer having improved heat resistance is included, but in any case, a vinyl chloride polymer [I] in which vinyl chloride units account for 80 mol% or more is usually used. For applications requiring particularly high heat resistance, it is preferable to use a chlorinated vinyl chloride polymer.

The present invention is characterized by the structure of the copolymer [II] blended as a modifier with the vinyl chloride polymer [I], and thus the copolymer [II] will be described in detail below.

This copolymer [II] is obtained by copolymerizing a predetermined amount of styrene, an N-substituted maleimide monomer and an unsaturated nitrile monomer as described above. Copolymer [I
The proportion of styrene units in the composition [I] is in the range of 20 to 68% by weight. If the amount is less than 20% by weight, the impact resistance and workability are insufficient, and if it exceeds 68% by weight, the heat resistance is insufficient. And a copolymer [II] having a modifying effect for the purpose of the present invention cannot be obtained.

Next, the N-substituted maleimide-based monomer is converted into a copolymer [II]
Has the effect of increasing the heat resistance improving effect of The proportion of the monomer in the copolymer [II] must be set in the range of 30 to 60% by weight, and if it is less than 30% by weight, the copolymer [II] has a sufficient heat resistance improving effect. On the other hand, if it exceeds 60% by weight, the affinity of the copolymer [II] with the vinyl chloride-based polymer [I] becomes poor, and the moldability of the resin composition becomes poor. In particular, when chlorinated vinyl chloride is used as the vinyl chloride-based polymer, N-
By using a substituted maleimide-based monomer having a content of 30 to 60% by weight, a resin composition having more excellent physical properties, particularly impact resistance, can be obtained.

Specific examples of the N-substituted maleimide monomer include N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-isobutylmaleimide, Nt-butylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-chlorophenylmaleimide, N
-Methylphenylmaleimide, N-bromophenylmaleimide, N-naphthylmaleimide, N-laurylmaleimide, 2-hydroxyethylmaleimide, N-hydroxyphenylmaleimide, N-methoxyphenylmaleimide, N-carboxyphenylmaleimide, Examples thereof include N-nitrophenylmaleimide, which can be used alone or in combination of two or more as necessary. Particularly preferred among these monomers is N
-Phenylmaleimide, N-cyclohexylmaleimide, N-chlorophenylmaleimide, N-methylmaleimide.

The unsaturated nitrile compound is an essential component for improving the impact resistance and solvent resistance of the copolymer [II], and the ratio of the monomer in the copolymer [II] is 2%. It should be set in the range of -40% by weight, more preferably 2-30% by weight. If the amount of the monomer is less than 2% by weight, sufficient impact resistance cannot be imparted to the copolymer [II]. On the other hand, if the amount exceeds 40% by weight, not only the processability is lowered but also the impact resistance is poor. Become. Specific examples of the unsaturated nitrile-based monomer include acrylonitrile, methacrylonitrile, phenylacrylonitrile and the like. Among them, acrylonitrile is the most common.
These unsaturated nitrile monomers can be used singly, or two or more of them can be used in combination, if necessary.

The preferred ratios of the styrene-N-substituted maleimide-based monomer and the unsaturated nitrile-based monomer constituting the copolymer [II] are as described above. In the case where the most preferable ratio for exhibiting the effect is shown, styrene: N-substituted maleimide monomer: unsaturated nitrile monomer = 30 to 68:30 to 50: 2
It is in the range of ~ 20.

The molecular weight of the copolymer [II] obtained by copolymerizing the above three components is not particularly limited, and is required for the required properties of the target vinyl chloride resin composition, especially for the moldability and the molded article. It can be selected from a wide range according to the degree of mechanical properties, heat resistance, etc., but generally 5,000 to 2,000,000
Degree, more usually in the range of 50,000 to 1,000,000. The molecular weight may be adjusted by the amount of catalyst added during the copolymerization reaction, the temperature, and the amount of chain transfer agent (butyl mercaptan, t-dodecyl mercaptan, mercaptoethanol, etc.).

There is no particular limitation on the copolymerization method, and any of a solution polymerization method, an emulsion polymerization method, a suspension polymerization method and the like may be employed. Examples of the polymerization initiator used in the polymerization include generally used free radical polymerization initiators such as benzoyl peroxide, potassium persulfate, ammonium persulfate, and oil-soluble or water-soluble peroxides such as hydrogen peroxide. An azo compound such as azobisisobutyronitrile can be used. At this time, it is also effective to promote the polymerization by using a reducing agent such as sodium bisulfite, ascorbic acid and ferrous sulfate in combination.

Examples of the organic solvent used in the solution polymerization include toluene, xylene, methyl isobutyl ketone, butyl cellosolve, dimethylformamide, 2-methylpyrrolidone, and sorbetso + 100 (manufactured by Tonen Petrochemical Co., Ltd.).

Examples of the emulsifier used in the emulsion polymerization include anionic emulsifiers such as potassium oleate, sodium dodecylbenzenesulfonate and sodium lauryl sulfate;
Nonionic emulsifiers such as polyoxyethylene nonylphenol ether and polyoxyethylene sorbitan ester; and cationic emulsifiers such as lauryltrimethylammonium chloride.

In addition, as a suspension stabilizer used in the case of suspension polymerization,
Examples thereof include calcium carbonate, barium carbonate, magnesium carbonate, polyvinyl alcohol, and alkali metal salts of a copolymer of methacrylic acid and methacrylic acid ester.

Among the above copolymerization methods, a solution polymerization method is particularly preferred. If this method is employed, a copolymer [II] in which the three copolymerizable monomers are randomly copolymerized is easily obtained, and vinyl chloride is used. It is possible to obtain a copolymer [II] having a more excellent modification effect on the system polymer [I]. By the way, α-methylstyrene copolymers, which are known as modifiers for vinyl chloride polymers, are difficult to produce by solution polymerization, and heterogeneous copolymers such as suspension polymerization and bulk polymerization are used. Therefore, it is considered that a considerable amount of the homopolymer was mixed in the product, which hindered the improvement of the modifying effect. In contrast, in the present invention, in which styrene is used as the main monomer component, the copolymerization reaction can be advanced in a homogeneous system by adopting the solution polymerization method, so that the amount of the homopolymer produced can be reduced, and vinyl chloride can be suppressed. It is considered that a copolymer [II] having an excellent modifying effect on the base resin can be obtained. However, the production method of the copolymer [II] used in the present invention is not limited to the solution polymerization method, but is the copolymer [II] obtained by the emulsion polymerization method or the suspension polymerization method as described above. Can also be used effectively as long as the type and ratio of the monomers used satisfy the above-mentioned prescribed requirements.

The vinyl chloride resin composition of the present invention contains the above-mentioned copolymer [II] and vinyl chloride polymer [I], and the most common production method is a previously produced vinyl chloride polymer. This is a method in which [I] and the copolymer [II] are melt-mixed. However, the present invention is not limited to this method, and it is also possible to employ various methods as described below, and those manufactured in this manner are also included in the technical scope of the present invention.

That is, the vinyl chloride-based polymer [I] is allowed to coexist in the monomer mixture used for producing the copolymer [II],
In the coexistence system, a solution polymerization, an emulsion polymerization, a method of performing a copolymerization by a suspension polymerization or the like, and a method of removing a solvent from a reaction product or coagulating, washing and drying a polymerization component, a resin composition of the present invention. Can be obtained.

The content of the copolymer [II] is preferably 5 to 50 parts by weight based on 100 parts by weight of the vinyl chloride-based polymer [I] in order to effectively exert the above-mentioned modification effect by the copolymer [II]. If the amount is less than 5 parts by weight, the effect is not clearly exhibited, while if it exceeds 50 parts by weight, the characteristics of the vinyl chloride polymer [I] are excellent. In addition, not only the moldability, impact resistance, flame retardancy, etc., are lowered, but also the material cost increases, which is not preferable.

The essential components of the present invention are a vinyl chloride polymer [I] and a copolymer [II], and other additives for general vinyl chloride resins such as plasticizers, fillers, stabilizers, and the like. Any suitable amount of a release agent, a colorant, a bleaching agent, an antistatic agent, an ultraviolet absorber, and the like can be freely added, and they are of course included in the technical scope of the present invention.

Next, the present invention will be specifically described with reference to examples, but the present invention is not limited to the following examples.

[Examples] Production Example of Copolymer Production Example 1 199.2 parts of styrene (hereinafter "parts" means "parts by weight" unless otherwise specified) and 16.6 parts of acrylonitrile in the stainless steel four-necked flask equipped with a stirrer. Parts and 10 parts of methyl ethyl ketone, and put in a nitrogen gas atmosphere.
Heated to 80 ° C. On the other hand, in another container, 116.2 parts of N-phenylmaleimide, 215.4 parts of methyl ethyl ketone and 1.5 parts of benzoyl peroxide were added and dissolved.
The mixture was dropped into the four-necked flask heated to 0 ° C. over 5 hours to carry out polymerization. The resulting polymer solution was diluted with 1690 parts of methyl ethyl ketone, and the polymer solution was diluted with 45 parts.
The polymer was poured into 00 parts of methanol to precipitate the polymer, followed by vacuum drying to obtain 310 parts of a white powdery copolymer (A). The weight average molecular weight of this copolymer (A) was about 150,000 (confirmed by GPC).

Production Examples 2 and 3 A copolymer was prepared in the same manner as in Production Example 1 except that 332 parts of a monomer mixture having the composition shown in Table 1 was used instead of styrene, acrylonitrile, and N-phenylmaleimide in Production Example 1. (B) and (C) were obtained.

Production Examples 4 and 5 The copolymer (D) was produced in the same manner as in Production Example 1 except that 1.5 parts of benzoyl peroxide in Production Example 1 was replaced with 0.5 part and 3 parts.
And (E) were obtained.

Comparative Production Examples 1 and 2 Styrene, acrylonitrile, N-
Copolymers (F) and (G) were obtained in the same manner as in Production Example 1, except that 332 parts of the monomer mixture having the composition shown in Table 1 was used instead of phenylmaleimide. Note that α-
In Comparative Production Example 2 using methylstyrene, the reaction yield of α-methylstyrene was as extremely low as 45%.

Examples 1 to 5 The copolymers (A) to (E) obtained in Production Examples 1 to 5 and a chlorinated vinyl chloride resin (polymerization degree: 800, chlorination degree: 70%, manufactured by Sekisui Chemical Co., Ltd., "HA- 31N ”), MBS resin (“ BTA-3NX ”, manufactured by Kureha Chemical Co., Ltd.), stearic acid, polyethylene wax, lead stearate and calcium stearate in a Henschel mixer at the blending ratio shown in Table 2 at 135 ° C. After mixing for a minute, a resin composition was obtained. This resin composition was kneaded with a hot roll having a diameter of 8 inches heated at 210 ° C. for 3 minutes to obtain a sheet-like resin composition, which was then pressed at 200 ° C. under a pressure of 150 kg / cm ² using a flat plate press. A specimen was prepared by press molding for minutes.

Table 2 also shows the results of measuring the heat distortion temperature (according to JIS K7207) and the Charpy impact value (according to JIS K7111) of the obtained specimen.

Comparative Examples 1 and 2 The copolymers (F) and (G) obtained in Comparative Production Examples 1 and 2 were used, and otherwise the preparation and molding of the resin composition were performed in the same manner as in Examples 1 to 5. , Performance evaluation.

The results are as shown in Table 2, and the resin compositions obtained in Examples 1 to 5 satisfying the requirements of the present invention were obtained in Comparative Examples 1 and 2.
It can be seen that the resin composition has excellent heat resistance and impact resistance as compared with the resin composition obtained in 2.

[Effects of the Invention] The present invention is constituted as described above and comprises styrene, N-
By blending a copolymer obtained by copolymerizing a substituted maleimide and an unsaturated nitrile monomer at a specific ratio into a vinyl chloride polymer as a modifying component, heat resistance, impact resistance, moldability, etc. It is possible to provide a vinyl chloride-based resin composition having a good vinyl chloride resin composition.

Continuing from the front page (72) Inventor Hideki Matsumura 992, Nishioki, Okihama-shi, Himeji-shi, Hyogo Prefecture Nippon Shokubai Chemical Industry Co., Ltd. 1 Himeji Laboratory, Nippon Shokubai Chemical Industry Co., Ltd. (72) Inventor Hiroshi Tsuboi 992, Nishioki, Okihama-shi, Abashiri-ku, Himeji-shi, Hyogo Pref. (JP, A) JP-A-3-39347 (JP, A) JP-A-4-96955 (JP, A) JP-A-2-265944 (JP, A) JP-A-63-2324043 (JP, A) ( 58) Surveyed field (Int.Cl. ⁷ , DB name) C08L 27/06 C08L 25/12 C08L 35/06

Claims (1)

(57) [Claims] 1. A vinyl chloride polymer [I] and styrene: 20 to 68% by weight, an N-substituted maleimide monomer: 30 to 60% by weight, and an unsaturated nitrile monomer: Two
A vinyl chloride resin composition having excellent heat resistance, impact resistance, and moldability, characterized by containing a copolymer of up to 40% by weight (100% by weight in total).