JPH03182536A - Vinyl chloride resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition excellent in heat resistance, impact resistance and hot-water creeping characteristics by mixing a vinyl chloride resin with a copolymer containing maleimide compound, methyl methacrylate and an aromatic vinyl compound. CONSTITUTION:A vinyl chloride resin composition excellent in heat resistance, impact resistance water resistance and especially hot-water creeping characteristics is obtained by homogeneously mixing 50-95wt.% vinyl chloride resin containing at least 80wt.% vinyl chloride as a polymer component with 50-5wt.% copolymer resin containing 30-60wt.% maleimide compound of the formula (wherein R is H, 1-4C alkyl, cyclohexyl or aryl), 5-40wt.% methyl methacrylate and 20-60wt.% aromatic vinyl compound as polymer components. By virtue of its properties, this composition can be extensively used in many fields including general-purpose engineering plastics for construction materials, automobile parts, electrical machine components, etc.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a vinyl chloride resin composition with excellent heat resistance, impact resistance, and hydrothermal creep properties, and this resin composition is used in building materials, electrical equipment, and automobiles. It can be effectively used as a composite engineering plastic material in the field of parts, etc.

[Prior Art] Vinyl chloride resins have excellent chemical, physical and mechanical properties and are very inexpensive, so they are used in floor desks in various fields. However, vinyl chloride resin itself has the disadvantage of poor heat resistance, so [A] Post-chlorination technology as a means to increase the heat resistance of vinyl chloride resin itself [B] Blending with a polymer that has a high softening temperature Techniques for imparting heat resistance, such as ■ Blending chlorinated polyvinyl chloride as a polymer with a high softening point (Japanese Patent Publication No. 62
-13987), or ■maleimide compound-
Method of blending styrene-methyl methacrylate copolymer (JP-A No. 63-196643, No. 63-4)
No. 6249, etc.) have been attempted.

[Problems to be Solved by the Invention] However, even with the above measure [A], the heat resistance is not improved to the desired level, and on the contrary, the moldability decreases due to the increase in the plasticization temperature, and the plasticization temperature increases. Problems arise such as difficulty in controlling the processing temperature as it approaches the pyrolysis temperature. Also, among the methods [B], first of all, in method (2) above, as the blending ratio of chlorinated polyvinyl chloride increases, the problem arises that its disadvantage, poor processability, becomes apparent. However, the blending amount of chlorinated polyvinyl chloride is restricted, and the effect of improving heat resistance cannot be sufficiently exhibited in practice.

Moreover, when chlorinated polyvinyl chloride is blended, the transparency decreases and the appearance deteriorates due to coloring.

On the other hand, in the method (■) above, although a certain degree of heat resistance improvement effect can be expected for unmodified vinyl chloride resin with a low softening point, chlorinated polyvinyl chloride itself has a certain degree of heat resistance improvement. However, the heat resistance cannot be improved any further, and furthermore, blending the copolymer causes a problem in that the impact resistance and hydrothermal creep properties deteriorate.

The present invention was made in view of the above-mentioned circumstances, and its purpose is to produce not only unmodified vinyl chloride resins with a low softening point but also chlorinated polyvinyl chloride resins that have undergone a certain degree of heat resistance improvement treatment. By developing a modifier that can provide even better heat resistance without reducing impact resistance or hydrothermal creep properties, and blending the modifier in an appropriate amount with vinyl chloride resin, The object of the present invention is to provide a vinyl chloride resin composition exhibiting excellent heat resistance, impact resistance, and hydrothermal creep properties.

[Means to solve the problem] The structure of the present invention that can solve the above problems is as follows: I.

+? .

Vinyl chloride resin containing 80% by weight or more of vinyl chloride as a polymerization component = 50 to 95% by weight; ■ Maleimide compound represented by the following general formula: more than 30% by weight and not more than 60% by weight, (in the formula, R is hydrogen, Represents an alkyl group, cyclohexyl group, or aryl group having 1 to 4 carbon atoms) ■Methyl methacrylate: 5 to 40% by weight ■Aromatic vinyl compound: 20 to 60% by weight Copolymer resin containing as a polymerization component = 50 to The gist is that it consists of a homogeneous blend of 5% by weight.

[Function] As described above, the vinyl chloride resin composition of the present invention is produced by copolymerizing a maleimide compound, methyl methacrylate, and an aromatic vinyl compound in a specific molar ratio to a vinyl chloride resin. Compounded in a specific ratio, this resin composition has excellent heat resistance and impact resistance due to the excellent modification effect of the above-mentioned copolymer resin! It has W properties, hydrothermal creep properties, and exhibits excellent workability.

Hereinafter, the composition of the composition of the present invention will be explained in detail.

First, the vinyl chloride resin that is the base of the present invention includes a homopolymer of vinyl chloride, a copolymer of a polymerizable monomer and vinyl chloride, or various modified products thereof. In the copolymer of vinyl chloride and vinyl chloride, the copolymerization ratio of the polymerizable monomer is suppressed to less than 20% by weight in order to effectively exhibit the effects of the vinyl chloride resin.

Examples of the polymerizable monomer include vinyl acetate, ethylene, propylene, methyl methacrylate, and N-substituted maleimide. Although various conventionally known modified products can be used as modified products, in the present invention, the most effective effect is exhibited by vinyl chloride resins whose heat resistance has been improved by chlorination. As the degree of chlorination increases, the effect of improving heat resistance increases, but if the degree of chlorination is too high, not only will thermal decomposition be more likely to occur, but moldability will also decrease, so chlorination is more preferable. degree is 57~
72 chlorinated vinyl chloride resin, and its preferred degree of polymerization is 500 to 15, considering mechanical strength and moldability.
00 range will be awarded.

Next, the copolymer blended into the vinyl chloride resin as a modifier contains the maleimide compound represented by the above-mentioned formula, methyl methacrylate, and an aromatic vinyl compound as essential monomer components. Among these, maleimide compounds mainly contribute to improving heat resistance, and specific examples include maleimide, N-methylmaleimide, N-ethylmaleimide, N-n-propylmaleimide, N-isopropylmaleimide, N-n-butylmaleimide, N-1
so-butylmaleimide, Nt-butylmaleimide,
Examples include N-cyclohexylmaleimide and N-phenylmaleimide, which can be used alone or in combination with 2f! if necessary. JI or higher can be used in combination. The proportion of the maleimide compound in the copolymer is 30
More than 60% by weight, more preferably 30% by weight! l amount%
It should be in the range of 50% by weight or less; if it is less than 30% by weight, sufficient heat resistance imparting effect cannot be obtained, while if it exceeds 60% by weight, the moldability and impact resistance of the resin composition will deteriorate. let

Methyl methacrylate improves the compatibility of the copolymer with vinyl chloride resins, contributing to improved transparency of the resin composition, and also has the effect of improving ionic impact resistance, hydrothermal creep properties, and processability. The proportion of methyl methacrylate in the copolymer is set in the range of 5 to 40% by weight, more preferably 5 to 30% by weight. If the amount of methyl methacrylate is less than 5% by weight, it will not be able to impart satisfactory hydrothermal creep properties and impact resistance to the resin composition, while if it is more than 40% by weight, it will not be able to provide the resin composition with satisfactory thermal creep properties and impact resistance. Not only the improvement effect becomes poor, but also the impact resistance improvement effect tends to decrease.

The aromatic vinyl compound, which is another monomer component constituting the copolymer, is an indispensable component for increasing the copolymerization reactivity of the maleimide compound and improving the heat resistance improvement effect. It also has the effect of reducing the amount of unreacted maleimide compound during copolymer production and increasing production efficiency.

Specific examples of aromatic vinyl compounds that exhibit such effects include styrene; o-, m+, p-methylstyrene (
vinyltoluene), 1.3-dimethylstyrene, 2.4
-dimethylstyrene, ethylstyrene, pt-butylstyrene, α-methylstyrene, α-ethylstyrene,
Alkylstyrenes such as α-methyl-p-methylstyrene; halogenated styrenes such as o-, m+, p-chlorostyrene, 2,4-dipromostyrene, 2-methyl-4-chlorostyrene, and halogenated alkylstyrenes, etc. is exemplified. Among these, styrene, vinyltoluene, and α-methylstyrene are particularly preferable from a comprehensive consideration of productivity, physical property improvement effect, cost, etc., and these may be used alone or in appropriate combinations of 2 ffi or more. I can do it. Note that α-methylstyrene is the most effective monomer when trying to obtain a higher level of heat resistance. The proportion of the aromatic vinyl compound in the copolymer is from 20 to
It should be set in the range of 60% by weight, more preferably 30 to 55% by weight; if it is less than 20% by weight, the copolymerization reactivity will be difficult to increase, while if it exceeds 60% by weight, it will not be satisfactory. Physical property modification effects cannot be obtained.

The copolymer used as a modifier in the present invention can be obtained by copolymerizing monomers containing the above three types in a manner described below. It is also possible to use a small amount of a polymerizable polymer as long as it does not disturb the above-mentioned preferred copolymerization ratio range. Such copolymerizable monomers include, for example, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, phthalic acid, or their half esters; cycloalkyl groups, benzyl groups, or C1-CI2 alkyl groups; acrylic acid esters having a group; methacrylic acid esters having a cyclohexyl group, benzyl group, or C2-CI2 alkyl group; unsaturated nitriles; olefins, dienes, etc.; 1 fill or 2f! within a range that does not inhibit the effect (usually 30!i amount% or less in terms of proportion in the copolymerization monomer component). The above can be used together.

The polymerization reaction using the above monomers may be carried out according to a known method, for example, under normal pressure, autogenous pressure or increased pressure, in an inert gas atmosphere, from a temperature of 0°C or less to 100°C.
The temperature is set in a wide temperature range exceeding .degree. C. depending on the type of monomer used, and any method such as solution polymerization, suspension polymerization, emulsion polymerization, etc. is carried out.

Examples of the polymerization initiator used include radical polymerization initiators such as oil-based or water-soluble peroxides such as benzoyl peroxide, potassium persulfate, ammonium persulfate, and hydrogen peroxide, and azo compounds such as azobisisobutyronitrile. is common. In this case, it is also effective to use a reducing agent such as sodium bisulfite, ascorbic acid, or ferrous sulfate as a redox catalyst to efficiently advance the polymerization reaction.

Examples of suspension stabilizers used in suspension polymerization include calcium carbonate, barium carbonate, magnesium carbonate, polyvinyl alcohol, and alkali metal salts of methacrylic acid-methacrylic acid ester copolymers. Examples of emulsifiers used in this case include anionic emulsifiers such as potassium oleate, sodium dodecylbenzenesulfonate, and sodium lauryl sulfate;
Preferred examples include nonionic emulsifiers such as polyoxyethylene nonylphenol ether and polyoxyethylene sorbitan ester, and anionic emulsifiers such as lauryltrimethylammonium chloride.

The solvent used during solution polymerization may be arbitrarily selected taking into account the composition of the monomers used, but numerical examples include toluene, xylene, methyl ethyl ketone, and methyl. Isobutyl ketone, butyl cellosolve, dimethylformamide, 2-methylpyrrolidone,
It is an organic solvent such as Tsurupetz #100 (manufactured by Tonen Petrochemical Co., Ltd.).

The above-mentioned polymerization reaction method does not limit the technical scope of the present invention, and can be carried out with appropriate modifications as necessary.
The outline of the production will be explained below using the solution polymerization method as an example.

A predetermined amount of a solvent, such as toluene, is charged in advance in a reaction container, and monomers of a maleimide compound (■), methyl methacrylate (■), an aromatic vinyl (■) and, if necessary, other monomers that can be copolymerized with these are added. Add the mixture and solvent if necessary to make a homogeneous mixture.

Separately, a polymerization initiator (for example, benzoyl peroxide) and a solvent are added and dissolved to prepare a homogeneous mixed solution. Predetermined reaction temperature (
The temperature is usually raised to 60 to 10°C>, and the above mixture is added under aeration of inert gas (e.g. nitrogen gas) and stirring to initiate polymerization, and then maintained at a predetermined temperature range for a certain period of time to complete polymerization. After the completion of polymerization, the reaction product is cooled.The reaction product is poured into a large amount of poor solvent (for example, methanol) to precipitate the polymer, and then filtered and dried to obtain the desired copolymer 1.
1 is obtained.

Since most of the maleimide compounds constituting this copolymer are solid at room temperature, in some cases they may not be completely dissolved in organic solvents or other monomers such as methyl methacrylate at room temperature. In such cases, in solution polymerization, a mixture of the maleimide compound and an organic solvent is heated to a temperature higher than the dissolution temperature, and the solution is then supplied to the reaction system, or when suspension polymerization is carried out, a polymerization initiator is added. Adding the free monomer mixture to an aqueous solution containing a suspension stabilizer,
After that, the maleimide compound is heated to a temperature higher than the dissolution temperature in other monomers to uniformly suspend it, and then a polymerization initiator is added to carry out polymerization to obtain the desired copolymer.
A method such as this may be adopted.

The molecular weight of the copolymer added as a modifier is not particularly limited, but if it is too high, the moldability of the resin composition will be poor, and if it is too low, the weather resistance, heat resistance, mechanical properties, etc. will be poor. Usually 5.0
00-1,000,000, preferably 10,000
A range of 500,000 to 500,000 is preferred. To adjust the molecular weight, commonly used chain transfer agents such as butyl mercaptan, tert-todecyl mercaptan, mercaptoethanol, etc. may be used.

The blending ratio of the vinyl chloride resin and the above copolymer is 5 for the former.
The latter should be in the range of 50 to 5% by weight relative to 0 to 95% by weight, and if the amount of the copolymer is less than this range, sufficient heat resistance cannot be imparted to the resin composition. On the other hand, if the amount exceeds this range, the impact resistance of the resin composition will become poor. A more preferable blending ratio of both is 40 to 5% by weight of the copolymer to 60 to 95% by weight of the vinyl chloride resin.
% by weight.

The thus obtained vinyl chloride resin composition of the present invention may contain other components, such as a heat stabilizer, a lubricant, an antioxidant, a coloring agent, etc., as desired, within a range that does not impede the characteristics of the present invention described above. Can be added. Furthermore, there are no restrictions on the method of producing a molded article using the resin composition of the present invention.
For example, any conventionally known method such as an extrusion molding method or an injection molding method can be employed.

Hereinafter, the structure and effects of the present invention will be explained in more detail with reference to Examples, but the present invention is not limited by the Examples below. Means "parts by weight."

[Example] 150 parts of toluene was charged as a solvent into a 4-hole stainless steel flask with an ffi stirrer and was heated under a nitrogen gas atmosphere to 90°C. In addition, 120 parts of N-phenylmaleimide, 24 parts of methyl methacrylate, 156 parts of styrene and 100 parts of toluene were added to a separate container.
The N-phenylmaleimide is dissolved by heating to 30-40°C. Furthermore, 50 parts of toluene and 3 parts of benzoyl peroxide are added to another container and dissolved. This solution was added dropwise over 4 hours to the above-mentioned four-bottle flask, which had been charged with toluene and heated to 90° C., to complete the polymerization. The obtained polymer solution was diluted with 450 parts of toluene, and this polymer solution was added to 1500 parts of methanol to precipitate the polymer, and then dried in a vacuum dryer at 80°C x 50 torr to form a white powder. 0280 parts of copolymer were obtained. The molecular weight of this copolymer ① is approximately 91.000 (G P C
(confirmed by peak value).

Examples 2 to 5, 1 to 5 In place of N-phenylmaleimide, methyl methacrylate, and styrene in Reference Example 1, 300 parts of a monomer mixture having the composition shown in Table 1 was used, and the other conditions were the same as in Reference Example 1. The operation was repeated to copolymerize the copolymers ■ to ■ obtained in Reference Examples 1 to 5 and chlorinated vinyl chloride resin (II degree 800, chlorination degree 70%, manufactured by Block Chemical Industry Co., Ltd., rHA- 31NJ), MBS resin (manufactured by Kureha Chemical Co., Ltd., rBTA-3NXJ), stearic acid, polyethylene wax, lead stearate, and calcium stearate were fed into a Henschel mixer at the blending ratio shown in Table 'M2, and mixed at 135°C for 2 minutes. A resin composition was obtained. This resin composition was subsequently supplied to a twin-screw extruder equipped with a vibrator mold to perform extrusion molding. The extrusion conditions were an extruder cylinder tip temperature of 195°C, an extruder head temperature of 200 t:, a resin temperature of 206°C, and a mold temperature of 205°C.

Vicat softening temperature (JIS
K7206), heat distortion temperature (JIS K720
7) and Charpy impact value (JIS K711
Table 1 also lists the results of the measurements.

Comparative Examples 1 to 5 Using the copolymers 1 to [phase] obtained in Comparative Reference Examples 1 to 5 above, resin compositions were prepared and extruded in the same manner as in Examples 1 to 5.

The results are shown in Table 2, and the resin compositions of Examples 1 to 5 that meet the specified requirements of the present invention have superior heat resistance and impact resistance compared to the compositions of Comparative Examples 1 to 5. Comparison [Effects of the Invention] The vinyl chloride resin composition of the present invention was excellent in heat resistance, impact resistance, and water resistance, especially in the hydrothermal creep test. Therefore, by taking advantage of its characteristics, it can be used in a wide range of fields, including general-purpose engineering plastics for building materials, automobile parts, electrical equipment parts, etc.

Claims (2)

[Claims] (1) I, a vinyl chloride resin containing 80% by weight or more of vinyl chloride as a polymerization component: 50 to 95% by weight, and II, (a) a maleimide compound represented by the following general formula: 3
More than 0% by weight but not more than 60% by weight, ▲Mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R represents hydrogen, an alkyl group having 1 to 4 carbon atoms, a cyclohexyl group, or an aryl group) (b) Methyl methacrylate : 5 to 40% by weight (c) Copolymer resin containing 20 to 60% by weight of aromatic vinyl compound as a polymerization component: 50 to 5% by weight of a vinyl chloride resin composition. thing. (2) The vinyl chloride resin composition according to claim 1, wherein the vinyl chloride resin is chlorinated polyvinyl chloride with a degree of chlorination of 57 to 72.