JPH0349306B2 - - Google Patents

Description

[Detailed description of the invention]

(Field of Industrial Application) The present invention has excellent heat resistance, weather resistance, impact resistance, and moldability, and can be used in various moldings such as roofing materials, building materials such as sizing, electrical equipment parts, automobile parts, pipes, hoses, disks, etc. The present invention relates to thermoplastic resin compositions useful for manufacturing products. Specifically, the present invention relates to a thermoplastic resin composition comprising a vinyl chloride polymer and a copolymer essentially containing a maleimide compound, methyl methacrylate, and styrene in specific proportions. (Prior art) Vinyl chloride resin has excellent physical and chemical properties and is used in a wide range of areas. However, in recent years, when applications have become more diversified, their use has been restricted depending on the application. To improve heat resistance, there is a so-called post-chlorinated vinyl chloride resin that is made by further chlorinating vinyl chloride resin with chlorine, but although it has improved heat resistance compared to conventional vinyl chloride resin, it has poor moldability. is extremely bad, and its range of applications is severely limited. In order to improve molding processability, there has been a conventional method of adding acrylic resin containing methyl methacrylate as a main component as a processing aid (Japanese Patent Publication No. 52-1746,
Japanese Patent Publication No. 52-49020) and methods that make extensive use of plasticizers have been adopted. Although moldability is improved by adding these acrylic processing aids, heat resistance is reduced. In particular, in the case of post-chlorinated vinyl chloride resin, a large amount of processing aid is required, and in some cases it may be necessary to use a blend with conventional vinyl chloride resin. It is not possible to demonstrate this and is forced to have low heat resistance. To improve the weather resistance of vinyl chloride resins, a method of blending them with acrylic resins has been adopted, and to improve their impact resistance, a method of blending them with graft polymers containing soft rubber components has been adopted. However, in either case, heat resistance decreases. (Problems to be Solved by the Invention) As described above, although the conventional methods improve each individual property, it is possible to obtain a thermoplastic resin that has good heat resistance, weather resistance, impact resistance, and moldability. No composition was obtained. In view of these points, the present inventors have conducted extensive research and have developed a thermoplastic resin that has improved heat resistance, weather resistance, impact resistance, and moldability without impairing its appearance by using a specific copolymer. It was discovered that a composition can be obtained, leading to the present invention. (Actions and means for solving the problems) The present invention is based on the general formula (In the formula, R is an alkyl group having 1 to 4 carbon atoms or a cyclohexyl group.) 5 to 30% by weight of the maleimide compound (A), 25 to 45% by weight of methyl methacrylate, 40 to 60% by weight of styrene, Other polymerizable monomers that can be copolymerized with these monomers
(B) 0 to 30% by weight (however, the total of the above monomers is 100% by weight)
Weight%. ) and a vinyl chloride polymer (), the thermoplastic resin composition has excellent appearance, heat resistance, weather resistance, water resistance, impact resistance, and moldability. It is something. The copolymer () in the present invention itself has excellent colorless transparency, heat resistance, weather resistance, etc.
Heat resistance, water resistance, moldability, etc. can be improved without impairing the appearance etc. of the vinyl chloride polymer (). The copolymer () is composed essentially of a maleimide compound (A), methyl methacrylate, and styrene, and if necessary, other polymerizable monomers (B) are used in combination. The maleimide compound (A) has heat resistance and
In addition to imparting solvent resistance, it also exhibits unexpected effects such as capturing free chlorine in the resin composition to suppress resin deterioration and reducing electrical resistance. Methyl methacrylate is a component for improving weather resistance, water resistance, impact resistance, and optical properties. In plastic products, improved water resistance is particularly desirable since it greatly contributes to dimensional stability. Styrene improves the processability when molding the thermoplastic resin composition of the present invention, and also increases the copolymerizability of the maleimide compound (A), thereby reducing the amount of unreacted maleimide compound (A). This contributes to improving productivity and makes the effect of improving heat resistance more pronounced. Therefore, the resin composition of the present invention consisting of the copolymer (2) and the vinyl chloride polymer (2) is superior to the conventional vinyl chloride resin composition due to the synergistic effect of each component of the copolymer (2). The excellent physical properties, chemical properties, and flame retardancy of A plastic resin composition is obtained. Maleimide compounds used in copolymers ()
(A) is represented by the above general formula, such as N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-
Examples include isobutylmaleimide, N-tertiarybutylmaleimide, N-cyclohexylmaleimide, and the like, and one or more of these can be used. Compound (A) is 5 to 30% by weight, preferably 10 to 20% by weight in the copolymer ()
Use the ratio. If the amount of maleimide compound (A) used is less than 5% by weight, sufficient heat resistance cannot be imparted to the resulting resin composition;
If the amount is more than % by weight, the molding processability of the resulting resin composition and the miscibility with the vinyl chloride polymer () will deteriorate, so both are not preferred. Methyl methacrylate is 25~ in copolymer ()
It is used in a proportion of 45% by weight, preferably 30-40% by weight. The weather resistance of the resin composition obtained when the amount of methyl methacrylate used is less than 25% by weight,
Molding processability deteriorates, and if the amount is more than 45% by weight, sufficient heat resistance cannot be imparted to the resulting resin composition, which are both undesirable. Styrene is 40-60% by weight in the copolymer (),
Preferably, it is used in a proportion of 45 to 55% by weight. If the amount of styrene used is less than 40% by weight,
The copolymerizability of the maleimide compound (A) decreases, and as a result, the effect of improving heat resistance is not sufficiently expressed, and if the amount is more than 60% by weight, the mechanical properties of the resulting resin composition deteriorate, which are both undesirable. The copolymer () is obtained by using the maleimide compound (A) represented by the above general formula, methyl methacrylate, and styrene in the above-mentioned amounts, and has colorless transparency and heat resistance only under the conditions limited in the present invention. A copolymer () with excellent properties such as hardness and weather resistance can be obtained.
The thermoplastic resin composition of the present invention has excellent weather resistance, impact resistance, and moldability. For example, if another N-substituted maleimide is used in place of the maleimide compound (A), or if one of the three components is used in an amount that deviates from the amount limited in the present invention, the above characteristics will no longer be achieved. A thermoplastic resin composition that satisfies all aspects cannot be obtained. When obtaining the copolymer (), if necessary, other polymerizable monomers (B) that can be copolymerized with the maleimide compound (A), methyl methacrylate, and styrene in a proportion not exceeding 30% by weight in the copolymer (). Can be used together. Other copolymerizable monomers (B) include unsaturated carboxylic acids such as (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, or half-esterified products thereof; methyl acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, tert-butyl (meth)acrylate, amyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate
Acrylate, lauryl (meth)acrylate,
Cycloalkyl groups such as cyclohexyl (meth)acrylate and benzyl (meth)acrylate, acrylic acid esters having an alkyl group having 1 to 12 carbon atoms, including a benzyl group, or methacrylic esters having an alkyl group having 2 to 12 carbon atoms ;α−
Vinyl aromatics other than styrene such as methylstyrene, paramethylstyrene, isopropenylstyrene, and vinyltoene; Unsaturated nitrites such as (meth)acrylonitrile; Olefins such as ethylene and propylene; Dienes such as butadiene and isoprene; Acetic acid Vinyl esters such as vinyl; vinyl halides such as vinyl chloride and vinyl fluoride; ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate,
Examples include polyunsaturated compounds such as divinylbenzene, and one or more selected from these groups can be used. Polymerizable monomer
(B) is used in an amount of 30% by weight or less, preferably 15% by weight or less in the copolymer (2), if necessary. In the present invention, unsaturated carboxylic acids are used as the polymerizable monomer (B) in the copolymer ().
It is preferable to use it in a proportion of 1 to 15% by weight, since the effect of improving heat resistance is further exhibited. If the amount of polymerizable monomer (B) used exceeds 30% by weight, a resin composition with excellent heat resistance, impact resistance, and moldability cannot be obtained. Vinyl chloride polymer used in the present invention ()
is a vinyl chloride copolymer containing 80% by weight or more of a vinyl chloride component, or a chlorinated vinyl chloride copolymer obtained by further adding chlorine to the copolymer, and is used alone or in combination. Methods for producing the thermoplastic resin composition of the present invention are not particularly limited, but include not only mechanical mixing of polymers, but also suspension polymerization, emulsion polymerization, bulk polymerization, or an appropriate combination of these methods. Conventionally known methods such as the method of For example, a method in which a copolymer () obtained by suspension polymerization, bulk polymerization, etc. and a polymer () are mixed, and then melted, kneaded, and extruded at a temperature of 150 to 300°C to obtain a thermoplastic resin composition. the copolymer () is present in the monomer mixture used to prepare the polymer (), and is subjected to bulk polymerization, suspension polymerization in an aqueous medium containing a suspension stabilizer, or emulsion polymerization; Method: A method in which the polymer () is present in a monomer mixture constituting the copolymer () and subjected to bulk polymerization, suspension polymerization, or emulsion polymerization; Monomers used to produce the copolymer () After emulsion polymerization of the polymer mixture and then adding the monomers used to produce the polymer () into the obtained emulsion copolymer and polymerizing it to produce a homogeneous and highly dispersible emulsion, Examples include a method of obtaining a powdery resin composition by coagulating, washing with water, and drying. The polymerization reaction employed to produce the thermoplastic resin composition of the present invention is carried out at temperatures ranging from 0°C or lower to 100°C or higher under autogenous pressure or under pressure and in an inert gas atmosphere. It will be held in The polymerization initiator used in the polymerization is a commonly used free radical polymerization initiator, such as oil-soluble or water-soluble peroxides such as benzoyl peroxide, potassium persulfate, ammonium persulfate, hydrogen peroxide, etc. Azo compounds such as azohisisobutyronitrile are suitable. It is also possible to use a reducing agent such as sodium bisulfite, ascorbic acid, or ferrous sulfate in combination to effectively advance the polymerization. Suspension stabilizers used during suspension polymerization include commonly used suspension stabilizers, such as calcium carbonate, barium carbonate, magnesium carbonate, polyvinyl alcohol, and copolymers of methacrylic acid and methacrylic ester. An alkali metal salt or the like may be used. Emulsifiers used in emulsion polymerization include commonly used emulsifiers, such as potassium oleate, sodium dodecylbenzenesulfonate,
Anionic emulsifiers such as sodium lauryl sulfate;
polyoxyethylene nonylphenol ether,
Nonionic emulsifiers such as polyoxyethylene sorbitan ester; cationic emulsifiers such as lauryltrimethylammonium chloride may be used as appropriate. The organic solvent used during solution polymerization is a commonly used organic solvent, such as toluene, xylene, methyl isobutyl ketone, butyl cellosolve, dimethyl formamide, 2-methylpyrrolidone, Solpetsuso +100 (manufactured by Tonen Petrochemical Co., Ltd.), etc. An organic solvent may be used as appropriate. Copolymer () constituting the resin composition of the present invention
The outline of the production will be explained below using the suspension polymerization method as an example. A suspension stabilizer such as polyvinyl alcohol is dissolved in an aqueous liquid at room temperature or under heating,
A polymerization initiator (e.g. benzoyl peroxide) is added and dissolved in a monomer mixture of maleimide compound (A), methyl methacrylate, styrene and, if necessary, other polymerizable monomers copolymerizable with these (B). The mixed solution is added under stirring and inert gas (for example, nitrogen gas) to create a suspension state, and then the temperature is raised to a predetermined reaction temperature (usually 60 to 100°C) to initiate polymerization. The polymerization is completed by maintaining the temperature within the temperature range for a certain period of time. After the completion of polymerization, the reaction product is cooled, filtered, washed with water, and dried to form the desired copolymer ().
is obtained. Maleimide compound (A) constituting the copolymer ()
Since most of these are solid at room temperature, in some cases they may not completely dissolve in the organic solvent used or other monomers such as methyl methacrylate and styrene at room temperature. In such a case, taking the above suspension polymerization as an example, a monomer mixture containing no polymerization initiator is added to an aqueous suspension stabilizer solution with stirring, and then other monomers of the maleimide compound (A) are added. After heating to a temperature higher than the solubility in the body and uniformly suspending it, a polymerization initiator is added and polymerized to form the desired copolymer ().
You can use a method such as obtaining . The molecular weight of the copolymer () is not particularly limited, but if it is too high, the molding processability 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 5000~2000000, preferably 10000~
A range of 1,000,000 is preferred. To adjust the molecular weight, commonly used chain transfer agents,
For example, butyl mercaptan, tertiary dodecyl mercaptan, mercaptoethanol, etc. may be used. The thermoplastic resin composition of the present invention can be obtained from the copolymer () and the vinyl chloride polymer () by the various methods described above. 50% by weight, vinyl chloride polymer () 50-95% by weight. If the proportion of the copolymer () used is a small amount outside the above range, the heat resistance and moldability of the resulting resin composition may be insufficient; Even if the amount exceeds the range, the effect commensurate with the amount used may not be sufficiently obtained and it may become uneconomical, and the versatility of the resin composition may be impaired, so care must be taken. When the polymer () is a post-chlorinated vinyl chloride polymer, the resin composition of the present invention has excellent heat resistance, moldability, etc., and does not have drawbacks such as decreased heat resistance like conventional compositions. There is no visible difference, and the original characteristics can be fully demonstrated. In addition, conventionally known additives can be used in combination with the thermoplastic resin composition of the present invention within a range that does not impair the object of the present invention. When the resin composition requires higher impact resistance, for example, acrylic ester, methacrylic ester, vinyl cyanide in the presence of 15 to 80 parts by weight of polybutadiene or a butadiene copolymer containing 50% by weight or more of butadiene. 1 selected from compounds
A monomer mixture consisting of a species or two or more monomers, an aromatic vinyl compound, and optionally a maleimide compound.
A graft copolymer obtained by copolymerizing 85 to 20 parts by weight, or 100 to 80% by weight of an acrylic acid alkyl ester, and 0 monomers copolymerizable with it.
In the presence of 15 to 80 parts by weight of a copolymer consisting of ~20% by weight and an appropriate amount of a crosslinkable monomer, a methacrylic acid ester, an acrylic acid alkyl ester, an aromatic vinyl compound, a vinyl cyanide compound, and optionally a maleimide compound. A graft copolymer obtained by copolymerizing 20 to 85 parts by weight of a monomer mixture may be used in combination. These graft copolymers are produced by known methods, generally emulsion polymerization. Further, a copolymer containing methacrylic acid ester as a main component may be used as a processing aid, and in some cases as a plasticizer for the vinyl chloride polymer (). Examples of other additives include plasticizers such as octyl esters of phthalic acid, trimellitic acid, and pyromellitic acid; stabilizers such as dibutyltin dimaleate, lead stearate, zinc stearate; and release agents such as stearic acid and potassium stearate. Examples include molding agents; fillers such as calcium carbonate and titanium oxide; bleaching agents, ultraviolet absorbers, and the like. (Effect of the invention) The thermoplastic resin composition of the invention has excellent appearance, heat resistance,
Because it has excellent weather resistance, water resistance, impact resistance, and moldability, it is used not only as general-purpose engineering plastics such as building materials, automobile parts, and electrical equipment parts, but also in special fields such as diskettes. . Next, the present invention will be explained in more detail with reference to Examples, but it goes without saying that the present invention is not limited to these Examples. In the examples, "parts" and "%" indicate parts by weight, respectively. Reference Example 1 550 parts of deionized water and 0.28 parts of polyvinyl alcohol (Gohsenol GH-20, manufactured by Nippon Gosei Co., Ltd.) were placed in the stainless steel four-necked flask equipped with a stirrer in step 1, and heated to 80°C under a nitrogen gas atmosphere. After completely dissolving the polyvinyl alcohol, the mixture was cooled to 50°C. Weigh out 48 parts of cyclohexylmaleimide, 77 parts of methyl methacrylate, and 115 parts of styrene into a separate container.
After heating to about 40°C to dissolve cyclohexylmaleimide, 9.6 parts of benzoyl peroxide was added and dissolved to obtain a uniform monomer solution. The entire amount of the obtained monomer solution was added to a four-necked flask, and stirred at 400 rpm for 10 minutes in a nitrogen gas atmosphere.
After holding for a minute to form a suspended state, the internal temperature was raised to 80° C. to initiate polymerization, and this temperature was then maintained for 7 hours to complete polymerization. The resulting aqueous suspension
The mixture was filtered through a 100-mesh filter cloth, thoroughly washed with deionized water, and then dried in a hot air circulating dryer at 90°C to obtain about 220 parts of granular copolymer (1) with a diameter of 0.5 mm. Reference Examples 2 to 5 and Comparative Reference Examples 1 to 4 Same as Reference Example 1 except that 240 parts of a monomer mixture having the composition shown in Table 1 was used instead of the monomer composition in Reference Example 1. The above operation was repeated to obtain copolymers (2) to (5) and comparative copolymers (1) to (6).

[Table] Examples 1 to 3 Using the copolymer (1) obtained in Reference Example 1 and a vinyl chloride resin (Sumirit SX-11F, manufactured by Sumitomo Chemical Co., Ltd., polymerization degree 1050), the polymerization shown in Table 2 was carried out. Resin compositions (1) to (3) consisting of the following formulations were prepared. Resin composition obtained
Each of (1) to (3) was kneaded for 5 minutes using a heated roll with a diameter of 8 inches heated to a surface temperature of 190°C to obtain a sheet-shaped resin composition, which was then kneaded using a flat plate press at a temperature of 190°C.
℃, press molded for 10 minutes under a pressure of 100Kg/ ^cm2 ,
A test piece was prepared. The appearance of the obtained test piece was good, and the softening temperature, Izod impact strength, and accelerated weathering resistance were measured using this test piece.
As shown in the table, it was found that the resin composition of the present invention showed good results. In addition, in each example,
Table 2 also shows the evaluation results of roll suitability during hot roll kneading of the resin composition, and the results were good without any problems. The softening temperature was measured according to JIS K-6745, the Izod impact strength was measured according to ASTM D-256, and the accelerated weather resistance was measured using a sunshine weather meter.
By observing the appearance after 1000 hours of irradiation,
○: Good, △: Slightly poor, ×: Poor. Roll suitability is determined by observing the hot roll kneading state.
○: Good, △: Slightly bad, ×: Bad. Comparative Example 1 A comparative composition (1) was prepared in the same manner as in Example 1 except that the copolymer (1) in Example 1 was not used, and then test pieces were prepared and evaluated in the same manner.
The results are shown in Table 2. Comparative composition (1) showed inferior results compared to resin compositions (1) to (3) obtained in Examples 1 to 3.

[Table] Examples 4 to 7 and Comparative Examples 2 to 7 Copolymers (2) to (5) obtained in Reference Examples 2 to 5 and comparative copolymers (1 )〜(6)
Resin compositions (4) to (7) and comparative compositions (2) to (7) were prepared with the same composition as in Example 1, except that Copolymer (1) was used in place of copolymer (1) in Example 1. Thereafter, test pieces were prepared and evaluated in the same way. The results are shown in Table 3.

【table】

Claims (1)

[Claims] 1. General formula (In the formula, R is an alkyl group having 1 to 4 carbon atoms or a cyclohexyl group.) 5 to 30% by weight of a maleimide compound (A) represented by
Methyl methacrylate 25-45% by weight, styrene 40
~60% by weight and 0 to 30% by weight of other polymerizable monomers (B) that can be copolymerized with these monomers (however, the total of the above monomers is 100% by weight). A thermoplastic resin composition comprising a copolymer (I) and a vinyl chloride polymer (2) and having excellent appearance, heat resistance, weather resistance, impact resistance, and moldability. 2. The thermoplastic resin composition according to claim 1, wherein an unsaturated carboxylic acid is used as the other polymerizable monomer (B) in an amount of 1 to 30% by weight in the copolymer ().