JP6475501B2 - Vinyl chloride resin heat-resistant reforming copolymer, molded body, vinyl chloride piping - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vinyl chloride resin heat-resistant modification copolymer, a vinyl chloride resin heat-resistant modification copolymer and a vinyl chloride resin, a molded body comprising the resin composition, and a vinyl chloride pipe. It is.

Vinyl chloride resin is used in a wide variety of applications such as water and sewer pipes, fittings, rain gutters, corrugated sheets, sashes, flooring, wallpaper, vinyl leather, hoses, and wire coverings. The use of the material is limited in the case of the above-mentioned problems and members that require heat resistance. In particular, PVC pipes are used for building materials such as water and sewer pipes because they are excellent in chemical resistance, durability, and flame resistance, and are lightweight and inexpensive. The method of use is limited for members that require heat resistance such as hot water or hot water or other members that require heat resistance. In order to improve the heat resistance of vinyl chloride resins, there are chlorinated vinyl chloride resins that are further chlorinated vinyl chloride resins, but the thermal stability during molding is poor, resulting in poor appearance due to coloring and gas burns. There is a problem that it ends up.

JP-A-8-27339 JP 2008-156391 A JP 2004-99669 A

The present invention provides a vinyl chloride resin heat-modifying copolymer that improves the heat resistance of a vinyl chloride resin and that can provide a molded article having good thermal stability and excellent appearance. In particular, it is an object to provide a vinyl chloride pipe excellent in heat resistance and thermal stability and having a good appearance.

The gist of the present invention is as follows.
(1) Aromatic vinyl monomer units 45 to 85% by mass, (meth) acrylic acid ester monomer units 5 to 45% by mass, unsaturated dicarboxylic acid anhydride monomer units 10 to 30% by mass, A copolymer for heat resistance modification of a vinyl chloride resin having a weight average molecular weight (Mw) of 100,000 to 200,000.
(2) The copolymer for heat-resistant modification of a vinyl chloride resin according to (1), wherein a melt mass flow rate (MFR) measured at 220 ° C. under a 98 N load is 0.5 to 20.0 g / min.
(3) The vinyl chloride resin heat-modifying copolymer according to (1) or (2), wherein the Vicat softening temperature measured at a load of 50 N is 110 to 150 ° C.
(4) A resin composition comprising 5 to 50% by mass of the vinyl chloride resin heat-resistant modifying copolymer according to any one of (1) to (3) and 50 to 95% by mass of the vinyl chloride resin.
(5) A molded article comprising the resin composition according to (4).
(6) A vinyl chloride pipe comprising the resin composition according to (4).

The copolymer of the present invention can improve the heat resistance of the vinyl chloride resin, and can provide a molded article having good thermal stability and excellent appearance. The vinyl chloride pipe of the present invention is used as a piping member. It can be suitably used.

<Explanation of terms>
In the present specification, for example, the description “A to B” means that it is A or more and B or less.

Hereinafter, embodiments of the present invention will be described in detail.

The vinyl chloride resin is a resin composed of vinyl chloride monomer units as shown in the following formula (1). Note that n is an integer indicating the degree of polymerization.

In the copolymer for heat resistance modification of vinyl chloride resin of the present invention, the aromatic vinyl monomer unit may be styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, ethyl. Examples include units derived from styrene monomers such as styrene, p-tert-butylstyrene, α-methylstyrene, and α-methyl-p-methylstyrene. Of these, styrene units are preferred. These aromatic vinyl monomer units may be one type or a combination of two or more types.

In the copolymer for heat resistance modification of vinyl chloride resin of the present invention, as the (meth) acrylic acid ester monomer unit, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, dicyclopentanyl methacrylate, Derived from methacrylic acid ester monomers such as isobornyl methacrylate and acrylic acid acrylate monomers such as methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-methyl hexyl acrylate, 2-ethyl hexyl acrylate, decyl acrylate The unit to do is mentioned. Among these, a methyl methacrylate unit is preferable. These (meth) acrylic acid ester monomer units may be one kind or a combination of two or more kinds.

In the copolymer for heat resistance modification of vinyl chloride resin of the present invention, as unsaturated dicarboxylic acid anhydride monomer units, maleic acid anhydride, itaconic acid anhydride, citraconic acid anhydride, aconitic acid anhydride, etc. Examples include units derived from anhydride monomers. Among these, maleic anhydride units are preferable. The unsaturated dicarboxylic acid anhydride monomer unit may be one type or a combination of two or more types.

The structural unit of the copolymer for heat resistance modification of the vinyl chloride resin of the present invention is 45 to 85% by mass of an aromatic vinyl monomer unit, 5 to 45% by mass of a (meth) acrylic acid ester monomer unit, and unsaturated. 10 to 30% by weight of dicarboxylic acid anhydride monomer unit, preferably 50 to 73% by weight of aromatic vinyl monomer unit, 8 to 38% by weight of (meth) acrylic acid ester monomer unit, unsaturated dicarboxylic acid It is 12-25 mass% of acid anhydride monomer units. In addition, the composition analysis of each monomer unit is a value measured under the measurement conditions described below by the C-13 NMR method.
Device name: FT-NMR AVANCE300 (manufactured by BRUKER)
Solvent: Deuterated chloroform Concentration: 14% by mass
Temperature: 27 ° C
Integration count: 8000 times

When the aromatic vinyl monomer unit is 85% by mass or less, the compatibility with the vinyl chloride resin and the effect of imparting heat resistance are improved. When the (meth) acrylic acid ester monomer unit is 45% by mass or less, a molded article having excellent thermal stability and good appearance when molded into a vinyl chloride resin. Is obtained. When the unsaturated dicarboxylic acid anhydride monomer unit is 30% by mass or less, a resin composition that can be molded while maintaining the effect of imparting heat resistance to the vinyl chloride resin is obtained. On the other hand, when the aromatic vinyl monomer unit is 45% by mass or more, when a resin composition obtained by blending with a vinyl chloride resin is molded, a molded article having excellent thermal stability and good appearance is obtained. can get. If the (meth) acrylic acid ester monomer unit is 5% by mass or more, compatibility with the vinyl chloride resin is improved while maintaining the heat resistance imparting effect to the vinyl chloride resin. When the unsaturated dicarboxylic acid anhydride monomer unit is 10% by mass or more, the effect of imparting heat resistance to the vinyl chloride resin is improved.

The vinyl chloride resin heat-modifying copolymer of the present invention is a copolymer other than aromatic vinyl monomer units, (meth) acrylic acid ester monomer units, and unsaturated dicarboxylic acid anhydride monomer units. Polymerizable vinyl monomer units may be included in the copolymer as long as the effects of the invention are not impaired, and the amount is preferably 5% by mass or less. Examples of the copolymerizable vinyl monomer unit include vinyl cyanide monomers such as acrylonitrile and methacrylonitrile, vinyl carboxylic acid monomers such as acrylic acid and methacrylic acid, N-methylmaleimide, and N-ethylmaleimide. N-alkylmaleimide monomers such as N-butylmaleimide and N-cyclohexylmaleimide, N-arylmaleimide monomers such as N-phenylmaleimide, N-methylphenylmaleimide and N-chlorophenylmaleimide Examples are units derived from the body. Two or more types of copolymerizable vinyl monomer units may be used.

The vinyl chloride resin heat-resistant modifying copolymer of the present invention preferably has a weight average molecular weight (Mw) of 100,000 to 200,000, more preferably a weight average molecular weight (Mw) of 120,000 to 180,000. . If the weight average molecular weight (Mw) is too large, the compatibility with a vinyl chloride resin having a low molding temperature will be poor, and the molding processability of the resulting resin composition and the appearance of the molded product may be inferior. If the weight average molecular weight (Mw) is too small, the molding processability and the strength of the molded product may be inferior. The weight average molecular weight (Mw) is a value in terms of polystyrene measured by gel permeation chromatography (GPC), and is a value measured under the measurement conditions described below.
Device name: SYSTEM-21 Shodex (manufactured by Showa Denko)
Column: 3 series PL gel MIXED-B Temperature: 40 ° C
Detection: Differential refractive index Solvent: Tetrahydrofuran Concentration: 2% by mass
Calibration curve: Prepared using standard polystyrene (PS) (manufactured by PL).

The vinyl chloride resin heat-resistant modifying copolymer of the present invention preferably has a melt mass flow rate (MFR) measured at 220 ° C. and a 98 N load of 0.5 to 20.0 g / min, more preferably 1 0.0-15.0 g / min. If the melt mass flow rate (MFR) is too low, the compatibility with a vinyl chloride resin having a low molding processing temperature is deteriorated, and the molding processability of the resulting resin composition and the appearance of the molded product may be inferior. If the melt mass flow rate (MFR) is too high, the moldability and the strength of the molded product may be inferior. The melt mass flow rate (MFR) is a value measured at 220 ° C. and 98 N load based on JIS K7210: 1999.

The vinyl chloride resin heat-resistant modifying copolymer of the present invention preferably has a Vicat softening temperature measured at 50 N load of 110 to 150 ° C, more preferably 120 to 145 ° C. When the Vicat softening temperature is in the range of 110 to 150 ° C., it is preferable because a resin composition having excellent heat resistance can be obtained by adding a predetermined amount to the vinyl chloride resin. The Vicat softening temperature is a measured value based on JIS K7206: 1999, using 50 specimens (load 50 N, heating rate 50 ° C./hour) with a test piece of 10 mm × 10 mm and a thickness of 4 mm.

The method for producing the vinyl chloride resin heat-resistant modification copolymer of the present invention will be described.
The polymerization mode is not particularly limited and can be produced by a known method such as solution polymerization or bulk polymerization, but solution polymerization is more preferable. The solvent used in the solution polymerization is preferably non-polymerizable from the viewpoint that a by-product is difficult to produce and that there are few adverse effects. The type of solvent is not particularly limited. For example, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and acetophenone, ethers such as tetrahydrofuran and 1,4-dioxane, toluene, ethylbenzene, xylene, and chlorobenzene Aromatic hydrocarbons, etc. are mentioned, but methyl ethyl ketone and methyl isobutyl ketone are preferred from the viewpoint of the solubility of the monomer and copolymer and the ease of solvent recovery. The addition amount of the solvent is preferably 10 to 100 parts by mass, more preferably 30 to 80 parts by mass with respect to 100 parts by mass of the copolymer to be obtained. If it is 10 parts by mass or more, it is suitable for controlling the reaction rate and the polymerization solution viscosity, and if it is 100 parts by mass or less, it is suitable for obtaining a desired weight average molecular weight (Mw).

The polymerization process may be any of a batch polymerization method, a semi-batch polymerization method, and a continuous polymerization method, but the batch polymerization method is suitable for obtaining a desired weight average molecular weight (Mw).

The polymerization method is not particularly limited, but is preferably a radical polymerization method from the viewpoint that it can be produced with high productivity by a simple process. The polymerization initiator is not particularly limited. For example, dibenzoyl peroxide, t-butyl peroxybenzoate, 1,1-bis (t-butylperoxy) -2-methylcyclohexane, t-butyl peroxy Known organic compounds such as isopropyl monocarbonate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyacetate, dicumyl peroxide, ethyl-3,3-di- (t-butylperoxy) butyrate Known azo compounds such as peroxides, azobisisobutyronitrile, azobiscyclohexanecarbonitrile, azobismethylpropionitrile, azobismethylbutyronitrile, and the like can be used. Two or more of these polymerization initiators can be used in combination. Among these, it is preferable to use an organic peroxide having a 10-hour half-life temperature of 70 to 110 ° C.

Polymerization is preferably performed so that the copolymer composition distribution becomes small during the polymerization. Since the aromatic vinyl monomer and unsaturated dicarboxylic acid anhydride monomer have strong alternating copolymerization, it corresponds to the polymerization rate of the aromatic vinyl monomer and the (meth) acrylate monomer. Thus, a method of continuously adding unsaturated dicarboxylic acid anhydride monomers is preferred. The control of the polymerization rate can be adjusted by the polymerization temperature, the polymerization time, and the addition amount of the polymerization initiator. It is preferable to continuously add a polymerization initiator because the polymerization rate can be more easily controlled. It is preferable to reduce the copolymer composition distribution because a copolymer having an excellent balance between heat resistance and strength can be obtained. The copolymer composition distribution can be evaluated by the transparency of the copolymer. As a measure of the copolymer composition distribution, the total light transmittance of 2 mm thickness measured based on ASTM D1003 is preferably 88% or more.

Furthermore, about the method of obtaining the copolymer which is the range of 100,000-200000 which is the range of preferable weight average molecular weight (Mw), in addition to adjustment of polymerization temperature, polymerization time, and polymerization initiator addition amount, solvent addition amount And it can obtain by adjusting chain transfer agent addition amount. Although it does not specifically limit as a chain transfer agent, For example, using well-known chain transfer agents, such as n-dodecyl mercaptan, t-dodecyl mercaptan, and 2, 4- diphenyl-4-methyl- 1-pentene. Can do.

After the polymerization is completed, the polymerization solution is optionally provided with a heat resistant stabilizer such as a hindered phenol compound, a lactone compound, a phosphorus compound, a sulfur compound, a light resistant stabilizer such as a hindered amine compound, a benzotriazole compound, Additives such as lubricants, plasticizers, colorants, antistatic agents and mineral oils may be added. The addition amount is preferably less than 0.2 parts by mass with respect to 100 parts by mass of all monomer units. These additives may be used alone or in combination of two or more.

There is no limitation in particular about the method of collect | recovering the vinyl chloride resin heat-resistant copolymer of this invention from a polymerization liquid, A well-known devolatilization technique can be used. For example, a method of continuously feeding the polymerization liquid to a twin-screw devolatilizing extruder using a gear pump and devolatilizing a polymerization solvent, an unreacted monomer and the like can be mentioned. The devolatilizing component including the polymerization solvent, unreacted monomer, etc. is condensed and recovered using a condenser, etc., and the polymerization solvent can be reused by purifying the condensate in a distillation tower. .

The vinyl chloride resin heat-modifying copolymer of the present invention thus obtained can be used as a heat-resistant modifying material for vinyl chloride resins. The method for kneading and mixing the vinyl chloride resin heat-modifying copolymer of the present invention and the vinyl chloride resin to obtain a resin composition is not particularly limited, and a known melt-kneading technique can be used. Examples of the melt-kneading apparatus that can be suitably used include a single screw extruder, a meshing type co-rotating or meshing type counter-rotating twin screw extruder, a screw extruder such as a non- or incomplete meshing type twin screw extruder, a Banbury mixer, There are kneaders and mixing rolls.

When the vinyl chloride resin is in a powder form, the vinyl chloride resin heat-resistant modifying copolymer of the present invention is preferably used after being pulverized into a powder form. The pulverization method is not particularly limited, and a known pulverization technique can be used. Examples of pulverizers that can be suitably used include a turbo mill pulverizer, a turbo disk mill pulverizer, a turbo cutter pulverizer, a jet mill pulverizer, an impact pulverizer, a hammer pulverizer, and a vibration pulverizer. .

The blending ratio of the vinyl chloride resin heat-modifying copolymer of the present invention and the vinyl chloride resin is 5 to 50% by mass of the vinyl chloride resin heat-modifying copolymer and 50 to 95% by mass of the vinyl chloride resin. The resulting resin composition is excellent in heat resistance, thermal stability and appearance. More preferably, it is 10 to 40% by mass of a vinyl chloride resin heat-modifying copolymer and 60 to 90% by mass of a vinyl chloride resin, 20 to 30% by mass of a vinyl chloride resin heat-modifying copolymer, and vinyl chloride. It is still more preferable that it is 70-80 mass% of resin.

The resin composition comprising the vinyl chloride resin heat-modifying copolymer of the present invention and the vinyl chloride resin includes a stabilizer, a plasticizer, a lubricant, an antioxidant, and an ultraviolet absorber as long as the effects of the present invention are not impaired. Additives such as a light stabilizer, a colorant, a compatibilizer, a filler, a processability improver, a reinforcing agent, an antistatic agent, a flame retardant, an initial color improver, and a conductivity imparting agent may be added. These additives may be used alone or in combination of two or more.

There is no particular limitation on the method of obtaining a vinyl chloride pipe by molding a resin composition comprising a copolymer and a vinyl chloride resin, and a known molding technique can be used. Suitable molding techniques include extrusion molding, calendar molding, injection molding, press molding, dipping, and coating.

Examples are given below to illustrate the present invention in more detail. However, the present invention is not limited to these examples.

<Example of production of copolymer (A-1)>
20% maleic anhydride solution dissolved in methyl isobutyl ketone so that maleic anhydride has a concentration of 20% by mass and methyl so that t-butylperoxy-2-ethylhexanoate is 2% by mass. A 2% t-butyl peroxy-2-ethylhexanoate solution diluted in isobutyl ketone was prepared in advance and used for the polymerization. A 120-liter autoclave equipped with a stirrer was charged with 2.8 kg of a 20% maleic anhydride solution, 24 kg of styrene, 10.4 kg of methyl methacrylate, and 40 g of t-dodecyl mercaptan, and the gas phase was replaced with nitrogen gas. Then, the temperature was raised to 88 ° C. over 40 minutes with stirring. While maintaining 88 ° C. after the temperature rise, 2.1% / hour of 20% maleic anhydride solution and 375 g / hour of 2% t-butylperoxy-2-ethylhexanoate solution were respectively added. The addition continued continuously over 8 hours. Thereafter, the addition of the 2% t-butylperoxy-2-ethylhexanoate solution was stopped, and 40 g of t-butylperoxyisopropyl monocarbonate was added. The 20% maleic anhydride solution was heated to 120 ° C. over 4 hours at a temperature rising rate of 8 ° C./hour while maintaining the addition rate of 2.1 kg / hour as it was. The addition of the 20% maleic anhydride solution was stopped when the amount of addition reached 25.2 kg. After the temperature rise, the polymerization liquid which has been held at 120 ° C. for 1 hour to finish the polymerization is continuously fed to a twin-screw devolatilizing extruder using a gear pump to remove methyl isobutyl ketone and a small amount of unreacted monomer. The pellet-shaped copolymer (A-1) was obtained by performing volatilization treatment and extruding and cutting into strands. The composition of the obtained copolymer (A-1) was analyzed by C-13 NMR method. Furthermore, the weight average molecular weight (Mw), melt mass flow rate (MFR), and Vicat softening temperature were measured. Table 1 shows the composition analysis results and various measurement results. Further, a 2 mm-thick mirror plate was molded with an injection molding machine, and the total light transmittance was measured with a haze meter. As a result, it was 91.8%.

<Example of production of copolymer (A-2)>
A 20% maleic anhydride solution and a 2% t-butylperoxy-2-ethylhexanoate solution were prepared in the same manner as A-1. A 120 liter autoclave equipped with a stirrer was charged with 3.8 kg of a 20% maleic anhydride solution, 24 kg of styrene, 8.4 kg of methyl methacrylate, and 32 g of t-dodecyl mercaptan, and the gas phase was replaced with nitrogen gas. Then, the temperature was raised to 88 ° C. over 40 minutes with stirring. While maintaining 88 ° C. after the temperature rise, a 20% maleic anhydride solution was added at a rate of 2.85 kg / hour and a 2% t-butylperoxy-2-ethylhexanoate solution was added at a rate of 300 g / hour, respectively. The addition continued continuously over 8 hours. Thereafter, the addition of the 2% t-butylperoxy-2-ethylhexanoate solution was stopped, and 40 g of t-butylperoxyisopropyl monocarbonate was added. The 20% maleic anhydride solution was heated up to 120 ° C. over 4 hours at a heating rate of 8 ° C./hour while maintaining the addition rate of 2.85 kg / hour. The addition of the 20% maleic anhydride solution was stopped when the addition amount reached 34.2 kg. After the temperature increase, the polymerization was terminated by maintaining 120 ° C. for 1 hour. The polymerization solution is continuously fed to a twin-screw devolatilizing extruder using a gear pump, and methyl isobutyl ketone and a small amount of unreacted monomer are devolatilized, and extruded into a strand to cut it. A polymer (A-2) was obtained. About the obtained copolymer (A-2), the composition analysis and the measurement of the weight average molecular weight (Mw), the melt mass flow rate (MFR), and the Vicat softening temperature were performed similarly to A-1. Table 1 shows the composition analysis results and various measurement results. Further, a 2 mm-thick mirror plate was molded with an injection molding machine, and the total light transmittance was measured with a haze meter. As a result, it was 90.2%.

<Example of production of copolymer (A-3)>
A 20% maleic anhydride solution and a 2% t-butylperoxy-2-ethylhexanoate solution were prepared in the same manner as A-1. A 120 liter autoclave equipped with a stirrer was charged with 2 kg of a 20% maleic anhydride solution, 24 kg of styrene, 12 kg of methyl methacrylate, 40 g of t-dodecyl mercaptan, and 5 kg of methyl isobutyl ketone. After the replacement, the temperature was raised to 88 ° C. over 40 minutes with stirring. After maintaining the temperature at 88 ° C., a 20% maleic anhydride solution was added at a rate of 1.5 kg / hour, and a 2% t-butylperoxy-2-ethylhexanoate solution was added at a rate of 375 g / hour. The addition continued continuously over 8 hours. Thereafter, the addition of the 2% t-butylperoxy-2-ethylhexanoate solution was stopped, and 40 g of t-butylperoxyisopropyl monocarbonate was added. The 20% maleic anhydride solution was heated to 120 ° C. over 4 hours at a temperature rising rate of 8 ° C./hour while maintaining the addition rate of 1.5 kg / hour. The addition of the 20% maleic anhydride solution was stopped when the amount of addition reached 18 kg. After the temperature increase, the polymerization was terminated by maintaining 120 ° C. for 1 hour. The polymerization solution is continuously fed to a twin-screw devolatilizing extruder using a gear pump, and methyl isobutyl ketone and a small amount of unreacted monomer are devolatilized, and extruded into a strand to cut it. A polymer (A-3) was obtained. About the obtained copolymer (A-3), the composition analysis and the measurement of the weight average molecular weight (Mw), the melt mass flow rate (MFR), and the Vicat softening temperature were performed similarly to A-1. Table 1 shows the composition analysis results and various measurement results. Further, a 2 mm-thick mirror plate was molded with an injection molding machine, and the total light transmittance was measured with a haze meter. As a result, it was 90.8%.

<Example of production of copolymer (A-4)>
A 20% maleic anhydride solution and a 2% t-butylperoxy-2-ethylhexanoate solution were prepared in the same manner as A-1. A 120 liter autoclave equipped with a stirrer was charged with 5 kg of a 20% maleic anhydride solution, 24 kg of styrene, 6 kg of methyl methacrylate, 50 g of t-dodecyl mercaptan, the gas phase was replaced with nitrogen gas, and stirred. The temperature was raised to 88 ° C. over 40 minutes. While maintaining 88 ° C. after the temperature rise, a 20% maleic anhydride solution was added at a rate of 3.75 kg / hour and a 2% t-butylperoxy-2-ethylhexanoate solution was added at a rate of 300 g / hour. The addition continued continuously over 8 hours. Thereafter, the addition of the 2% t-butylperoxy-2-ethylhexanoate solution was stopped, and 40 g of t-butylperoxyisopropyl monocarbonate was added. The 20% maleic anhydride solution was heated to 120 ° C. over 4 hours at a heating rate of 8 ° C./hour while maintaining the addition rate of 3.75 kg / hour. The addition of the 20% maleic anhydride solution was stopped when the addition amount reached 45 kg. After the temperature increase, the polymerization was terminated by maintaining 120 ° C. for 1 hour. The polymerization solution is continuously fed to a twin-screw devolatilizing extruder using a gear pump, and methyl isobutyl ketone and a small amount of unreacted monomer are devolatilized, and extruded into a strand to cut it. A polymer (A-4) was obtained. About the obtained copolymer (A-4), the composition analysis and the measurement of the weight average molecular weight (Mw), the melt mass flow rate (MFR), and the Vicat softening temperature were performed similarly to A-1. Table 1 shows the composition analysis results and various measurement results. Further, a 2 mm-thick mirror plate was molded with an injection molding machine, and the total light transmittance was measured with a haze meter. As a result, it was 90.0%.

<Example of production of copolymer (A-5)>
A 20% maleic anhydride solution and a 2% t-butylperoxy-2-ethylhexanoate solution were prepared in the same manner as A-1. A 120-liter autoclave equipped with a stirrer was charged with 2.8 kg of a 20% maleic anhydride solution, 13.8 kg of styrene, 16 kg of methyl methacrylate, and 48 g of t-dodecyl mercaptan, and the gas phase was replaced with nitrogen gas. Then, the temperature was raised to 88 ° C. over 40 minutes with stirring. After maintaining the temperature at 88 ° C., 20% maleic anhydride solution was 2.8 kg / hour, styrene 0.5 kg / hour, and 2% t-butylperoxy-2-ethylhexanoate solution was 300 g / hour. The addition was continued continuously over a period of 6 hours at the rate of hourly addition. Thereafter, the addition of the 2% t-butylperoxy-2-ethylhexanoate solution was stopped, and 20 g of t-butylperoxyisopropyl monocarbonate was added. The 20% maleic anhydride solution and styrene were heated to 118 ° C. over 3 hours at a heating rate of 10 ° C./hour while maintaining the addition rate of 2.8 kg / hour and 0.5 kg / hour respectively. Warm up. When the addition of 20% maleic anhydride solution reached 25.2 kg in total, the addition of styrene was stopped when the addition of styrene reached 4.5 kg. After the temperature rise, the polymerization was terminated by maintaining 118 ° C. for 1 hour. The polymerization solution is continuously fed to a twin-screw devolatilizing extruder using a gear pump, and methyl isobutyl ketone and a small amount of unreacted monomer are devolatilized, and extruded into a strand to cut it. A polymer (A-5) was obtained. About the obtained copolymer (A-5), the composition analysis and the measurement of the weight average molecular weight (Mw), the melt mass flow rate (MFR), and the Vicat softening temperature were performed similarly to A-1. Table 1 shows the composition analysis results and various measurement results. Further, a 2 mm-thick mirror plate was molded with an injection molding machine, and the total light transmittance was measured with a haze meter. As a result, it was 89.5%.

<Example of production of copolymer (A-6)>
A 25% maleic anhydride solution and a 2% t-butylperoxy-2-ethylhexanate solution were prepared in the same manner as (A-1). A 120-liter autoclave equipped with a stirrer was charged with 1.68 kg of a 25% maleic anhydride solution, 14.8 kg of styrene, 1 kg of methyl methacrylate, and 10 g of t-dodecyl mercaptan, and the gas phase was replaced with nitrogen gas. The temperature was raised to 97 ° C. over 40 minutes with stirring. While maintaining the temperature at 97 ° C. after the temperature increase, a 25% maleic acid-free aqueous solution and a 2% t-butylperoxy-2-ethylhexanoate solution were each continuously added. The 25% maleic anhydride solution is 1.61 kg / hour from the 6th hour of the addition, 0.91 kg / hour from the 6th to the 9th hour, and 0.66 kg from the 9th to the 12th hour. / Hour, the addition speed was changed stepwise so that the addition speed of 0.25 kg / hour from the 12th to the 15th hour was added, and a total of 15.12 kg was added. The 2% t-butylperoxy-2-ethylhexanonate solution was dispensed at a rate of 0.13 kg / hour from the start of the addition until the 9th hour and 0.3 kg / hour from the 9th to the 15th hour. The addition speed was changed stepwise so that 2.97 kg in total was added. The polymerization temperature is maintained at 97 ° C. until 9 hours from the start of the addition, and then increased to 118 ° C. over 6 hours at a temperature increase rate of 3.5 ° C./hour, and further maintained at 118 ° C. for 1 hour. The polymerization was terminated. The polymerization solution is continuously fed to a twin-screw devolatilizing extruder using a gear pump, and methyl isobutyl ketone and a small amount of unreacted monomer are devolatilized, and extruded into a strand to cut it. A polymer (A-6) was obtained. About the obtained copolymer (A-6), the composition analysis and the measurement of the weight average molecular weight (Mw), the melt mass flow rate (MFR), and the Vicat softening temperature were performed similarly to A-1. Table 1 shows the composition analysis results and various measurement results. Further, a 2 mm-thick mirror plate was molded with an injection molding machine, and the total light transmittance was measured with a haze meter. As a result, it was 89.5%.

<Example of production of copolymer (B-1)>
A 20% maleic anhydride solution and a 2% t-butylperoxy-2-ethylhexanoate solution were prepared in the same manner as A-1. A 120-liter autoclave equipped with a stirrer was charged with 2.8 kg of a 20% maleic anhydride solution, 24 kg of styrene, and 10.4 kg of methyl methacrylate, and the gas phase portion was replaced with nitrogen gas. The temperature was raised to 88 ° C. over 40 minutes. While maintaining 88 ° C. after the temperature rise, a 20% maleic anhydride solution was added at a rate of 1.68 kg / hour, and a 2% t-butylperoxy-2-ethylhexanoate solution was added at a rate of 200 g / hour, respectively. The addition continued continuously over 10 hours. Thereafter, the addition of the 2% t-butylperoxy-2-ethylhexanoate solution was stopped, and 20 g of t-butylperoxyisopropyl monocarbonate was added. The 20% maleic anhydride solution was heated to 120 ° C. over 5 hours at a temperature increase rate of 6.4 ° C./hour, while maintaining the addition rate of 1.68 kg / hour. The addition of the 20% maleic anhydride solution was stopped when the amount of addition reached 25.2 kg. After the temperature rise, the polymerization liquid which has been held at 120 ° C. for 1 hour to finish the polymerization is continuously fed to a twin-screw devolatilizing extruder using a gear pump to remove methyl isobutyl ketone and a small amount of unreacted monomer. Volatilization treatment was performed, and extrusion-cutting into strands was performed to obtain a pellet-shaped copolymer (B-1). About the obtained copolymer (B-1), the composition analysis and the measurement of the weight average molecular weight (Mw), the melt mass flow rate (MFR), and the Vicat softening temperature were performed similarly to A-1. Table 2 shows the composition analysis results and various measurement results. Further, a 2 mm-thick mirror plate was molded with an injection molding machine, and the total light transmittance was measured with a haze meter. As a result, it was 90.3%.

<Example of production of copolymer (B-2)>
A 20% maleic anhydride solution and a 2% t-butylperoxy-2-ethylhexanoate solution were prepared in the same manner as A-1. A 120 liter autoclave equipped with a stirrer was charged with 2.8 kg of a 20% maleic anhydride solution, 24 kg of styrene, 10.4 kg of methyl methacrylate, and 300 g of t-dodecyl mercaptan, and the gas phase was replaced with nitrogen gas. Then, the temperature was raised to 88 ° C. over 40 minutes with stirring. While maintaining 88 ° C. after the temperature rise, 2.1% / hour of 20% maleic anhydride solution and 375 g / hour of 2% t-butylperoxy-2-ethylhexanoate solution were respectively added. The addition continued continuously over 8 hours. Thereafter, the addition of the 2% t-butylperoxy-2-ethylhexanoate solution was stopped, and 40 g of t-butylperoxyisopropyl monocarbonate was added. The 20% maleic anhydride solution was heated to 120 ° C. over 4 hours at a temperature rising rate of 8 ° C./hour while maintaining the addition rate of 2.1 kg / hour as it was. The addition of the 20% maleic anhydride solution was stopped when the amount of addition reached 25.2 kg. After the temperature rise, the polymerization liquid which has been held at 120 ° C. for 1 hour to finish the polymerization is continuously fed to a twin-screw devolatilizing extruder using a gear pump to remove methyl isobutyl ketone and a small amount of unreacted monomer. The pellet-shaped copolymer (B-2) was obtained by performing volatilization treatment and extruding and cutting into strands. About the obtained copolymer (B-2), the composition analysis and the measurement of the weight average molecular weight (Mw), the melt mass flow rate (MFR), and the Vicat softening temperature were performed similarly to A-1. Table 2 shows the composition analysis results and various measurement results. Further, a 2 mm-thick mirror plate was molded with an injection molding machine, and the total light transmittance was measured with a haze meter. As a result, it was 91.5%.

<Example of production of copolymer (B-3)>
A 20% maleic anhydride solution and a 2% t-butylperoxy-2-ethylhexanoate solution were prepared in the same manner as A-1. A 120 liter autoclave equipped with a stirrer was charged with 8 kg of 20% maleic anhydride solution, 0.8 kg of styrene, 17.6 kg of methyl methacrylate and 30 g of t-dodecyl mercaptan, and the gas phase was replaced with nitrogen gas. Then, the temperature was raised to 88 ° C. over 40 minutes with stirring. While maintaining 88 ° C. after the temperature rise, a 20% maleic anhydride solution was added at a rate of 2.5 kg / hour and a 2% t-butylperoxy-2-ethylhexanoate solution was added at a rate of 250 g / hour, respectively. The addition continued continuously over 6 hours. Thereafter, the addition of the 2% t-butylperoxy-2-ethylhexanoate solution was stopped, and 10 g of t-butylperoxyisopropyl monocarbonate was added. The 20% maleic anhydride solution was heated to 120 ° C. over 2 hours at a temperature increase rate of 16 ° C./hour while maintaining the addition rate of 2.5 kg / hour. The addition of the 20% maleic anhydride solution was stopped when the addition amount reached 20 kg. After the temperature increase, the polymerization was terminated by maintaining 120 ° C. for 1 hour. The polymerization solution is continuously fed to a twin-screw devolatilizing extruder using a gear pump, and methyl isobutyl ketone and a small amount of unreacted monomer are devolatilized, and extruded into a strand to cut it. A polymer (B-3) was obtained. About the obtained copolymer (B-3), the composition analysis and the measurement of the weight average molecular weight (Mw), the melt mass flow rate (MFR), and the Vicat softening temperature were performed similarly to A-1. Table 2 shows the composition analysis results and various measurement results. Further, a 2 mm-thick mirror plate was molded with an injection molding machine, and the total light transmittance was measured with a haze meter. As a result, it was 88.8%.

<Example of production of copolymer (B-4)>
A 10% maleic anhydride solution dissolved in methyl isobutyl ketone so that the maleic anhydride has a concentration of 10% by mass and methyl so that t-butylperoxy-2-ethylhexanoate may be 2% by mass. A 2% t-butyl peroxy-2-ethylhexanoate solution diluted in isobutyl ketone was prepared in advance and used for the polymerization. A 120 liter autoclave equipped with a stirrer was charged with 2 kg of a 10% maleic anhydride solution, 24 kg of styrene, 14 kg of methyl methacrylate, 48 g of t-dodecyl mercaptan, and 2 kg of methyl isobutyl ketone, and the gas phase part was filled with nitrogen gas. After the replacement, the temperature was raised to 90 ° C. over 40 minutes with stirring. After maintaining the temperature at 90 ° C., a 10% maleic anhydride solution was added at a rate of 1.5 kg / hour and a 2% t-butylperoxy-2-ethylhexanoate solution was added at a rate of 300 g / hour. The addition continued continuously over 8 hours. Thereafter, the addition of the 2% t-butylperoxy-2-ethylhexanoate solution was stopped, and 40 g of t-butylperoxyisopropyl monocarbonate was added. The 10% maleic anhydride solution was heated to 120 ° C. over 4 hours at a temperature rising rate of 7.5 ° C./hour while maintaining the addition rate of 1.5 kg / hour. The addition of the 10% maleic anhydride solution was stopped when the addition amount reached 18 kg. After the temperature increase, the polymerization was terminated by maintaining 120 ° C. for 1 hour. The polymerization solution is continuously fed to a twin-screw devolatilizing extruder using a gear pump, and methyl isobutyl ketone and a small amount of unreacted monomer are devolatilized, and extruded into a strand to cut it. A polymer (B-4) was obtained. About the obtained copolymer (B-4), the composition analysis and the measurement of the weight average molecular weight (Mw), the melt mass flow rate (MFR), and the Vicat softening temperature were performed similarly to A-1. Table 2 shows the composition analysis results and various measurement results. Further, a 2 mm-thick mirror plate was molded with an injection molding machine, and the total light transmittance was measured with a haze meter. As a result, it was 90.1%.

<Example of production of copolymer (B-5)>
A 25% maleic anhydride solution and a 2% t-butylperoxy-2-ethylhexanoate solution were prepared in the same manner as A-1. A 120-liter autoclave equipped with a stirrer was charged with 4.9 kg of a 25% maleic anhydride solution, 29 kg of styrene, 4.3 kg of methyl methacrylate, and 30 g of t-dodecyl mercaptan, and the gas phase was replaced with nitrogen gas. Then, the temperature was raised to 92 ° C. over 40 minutes with stirring. While maintaining 92 ° C. after the temperature rise, a 25% maleic anhydride solution was added at a rate of 4.5 kg / hour and a 2% t-butylperoxy-2-ethylhexanoate solution was added at a rate of 250 g / hour, respectively. The addition continued continuously over 8 hours. Thereafter, the addition of the 2% t-butylperoxy-2-ethylhexanoate solution was stopped, and 40 g of t-butylperoxyisopropyl monocarbonate was added. The 25% maleic anhydride solution was heated to 120 ° C. over 4 hours at a heating rate of 8 ° C./hour while maintaining the addition rate of 3.75 kg / hour. The addition of the 25% maleic anhydride solution was stopped when the addition amount reached 44 kg. After the temperature increase, the polymerization was terminated by maintaining 120 ° C. for 1 hour. The polymerization solution is continuously fed to a twin-screw devolatilizing extruder using a gear pump, and methyl isobutyl ketone and a small amount of unreacted monomer are devolatilized, and extruded into a strand to cut it. A polymer (B-5) was obtained. About the obtained copolymer (B-5), the composition analysis and the measurement of the weight average molecular weight (Mw), the melt mass flow rate (MFR), and the Vicat softening temperature were performed similarly to A-1. Table 2 shows the composition analysis results and various measurement results. Further, a 2 mm-thick mirror plate was molded with an injection molding machine, and the total light transmittance was measured with a haze meter. As a result, it was 88.6%.

<Example of production of copolymer (B-6)>
A 20% maleic anhydride solution and a 2% t-butylperoxy-2-ethylhexanoate solution were prepared in the same manner as A-1. A 120-liter autoclave equipped with a stirrer was charged with 1.2 kg of a 20% maleic anhydride solution, 35.2 kg of styrene, 30 g of t-dodecyl mercaptan, and 2 kg of methyl isobutyl ketone, and the gas phase was replaced with nitrogen gas. Then, it heated up to 92 degreeC over 40 minutes, stirring. While maintaining 92 ° C. after the temperature rise, a 20% maleic anhydride solution was added at a rate of 0.76 kg / hour and a 2% t-butylperoxy-2-ethylhexanoate solution was added at a rate of 250 g / hour, respectively. The addition continued continuously over 15 hours. Thereafter, the addition of the 2% t-butylperoxy-2-ethylhexanoate solution was stopped, and 60 g of t-butylperoxyisopropyl monocarbonate was added. The 20% maleic anhydride solution was heated to 128 ° C. over 9 hours at a temperature increase rate of 4 ° C./hour while maintaining the addition rate of 0.76 kg / hour. The addition of the 20% maleic anhydride solution was stopped when the addition amount reached 18.24 kg. After the temperature increase, the polymerization was terminated by maintaining 128 ° C. for 1 hour. The polymerization solution is continuously fed to a twin-screw devolatilizing extruder using a gear pump, and methyl isobutyl ketone and a small amount of unreacted monomer are devolatilized, and extruded into a strand to cut it. A polymer (B-6) was obtained. About the obtained copolymer (B-6), the composition analysis and the measurement of the weight average molecular weight (Mw), the melt mass flow rate (MFR), and the Vicat softening temperature were performed similarly to A-1. Table 2 shows the composition analysis results and various measurement results. Further, a 2 mm-thick mirror plate was molded with an injection molding machine, and the total light transmittance was measured with a haze meter. As a result, it was 88.0%.

<Examples 1 to 10, Comparative Examples 1 to 7>
97% by mass of vinyl chloride resin, 1% by mass of lubricant, and 2% by mass of stabilizer were melt kneaded at a cylinder temperature of 190 ° C. with a single screw extruder (SE-65CA manufactured by Toshiba Machine Co., Ltd.). 1) was produced. Ratio (mass) of the copolymers (A-1) to (A-6) or the copolymers (B-1) to (B-6) and the vinyl chloride resin (C-1) shown in Tables 3 to 4 %) And then melt kneaded at a cylinder temperature of 190 ° C. in a single screw extruder to prepare a resin composition. In addition to preparing a test piece from this resin composition by injection molding, it was melt-kneaded at a cylinder temperature of 190 ° C. and extruded at a mold temperature of 180 ° C. with an oblique biaxial extruder (TEC 67 manufactured by Toshiba Machine Co., Ltd.). Molding was performed to produce a round pipe (outer diameter 60 mm, wall thickness 1.2 mm). This round pipe was cut into a length of 500 mm using a plastic pipe cutter (EA338BF manufactured by KTS) to obtain a vinyl chloride pipe. The following evaluation was performed using this resin composition, and the evaluation results are shown in Tables 3 to 4. The vinyl chloride resin used was “TH-1000” manufactured by Taiyo Vinyl Co., Ltd., the lubricant was Stearic Acid Sakura manufactured by NOF Corporation, and the stabilizer used was “TVS # 8832” manufactured by Nitto Kasei.

<Comparative Example 8>
As the chlorinated vinyl chloride resin, “H516A” manufactured by Kaneka Corporation was used.

(Composition analysis)
The composition analysis of each monomer unit was measured by the C-13 NMR method under the measurement conditions described below.
Device name: JNM-ECX series FT-NMR (manufactured by JEOL)
Solvent: Deuterated chloroform Concentration: 14% by mass
Temperature: 27 ° C
Integration count: 8000 times

(Weight average molecular weight)
The weight average molecular weight (Mw) is a polystyrene equivalent value measured by gel permeation chromatography (GPC), and was measured under the conditions described below.
Device name: SYSTEM-21 Shodex (manufactured by Showa Denko)
Column: 3 series PL gel MIXED-B Temperature: 40 ° C
Detection: Differential refractive index Solvent: Tetrahydrofuran Concentration: 2% by mass
Calibration curve: Prepared using standard polystyrene (PS) (manufactured by PL).

(Melt mass flow rate)
The melt mass flow rate (MFR) was measured at 220 ° C. and 98 N load based on JIS K7210: 1999. The measuring machine used was a melt indexer F-F01 manufactured by Toyo Seiki Seisakusho.

(Vicat softening point)
The Vicat softening point was measured according to JIS K7206: 1999 using 50 specimens (load 50 N, temperature rising rate 50 ° C./hour) with a test piece of 10 mm × 10 mm and a thickness of 4 mm. In addition, the measuring machine used the Toyo Seiki Seisakusho HDT & VSPT test apparatus.

(Heating deformation rate)
A test piece having a length of 30 mm, a width of 200 mm, and a thickness of 2 mm was prepared, and heated at a temperature of 60 ° C. for 60 minutes using a warm air dryer (DN-43H manufactured by Yamato). Further, a vinyl chloride pipe having an outer diameter of 60 mm, a wall thickness of 1.2 mm, and a length of 500 mm was placed in a gear oven (60 UL manufactured by Toyo Seiki Co., Ltd.) and heated at a temperature of 55 ° C. for 3 hours. The heating deformation rate was calculated as an absolute value using the following formula from the lateral length before and after heating in the former case and from the length before and after heating (length in the extrusion direction) in the latter case. A heat deformation rate of 2.0% or less was accepted.
Heat deformation rate (%) = (| length after heating−length before heating |) / length before heating × 100%

(appearance)
Appearance evaluation was performed by visually observing 50 test pieces having a length of 90 mm, a width of 90 mm, and a thickness of 2 mm, and counting the number of samples in which appearance defects such as coloring, bubbles, burn-out contamination, and bumps occurred. Further, visual observation was performed on 30 vinyl chloride pipes having an outer diameter of 60 mm, a wall thickness of 1.2 mm, and a length of 500 mm, and the same appearance evaluation was performed. The evaluation criteria are as follows.
◎: Number of appearance defect samples 0 to 1 ○: Number of appearance defect samples 2 to 5 Δ: Number of appearance defect samples 6 to 10 x: Number of appearance defect samples 11 or more

(Thermal stability)
A vinyl chloride pipe having an outer diameter of 60 mm, a wall thickness of 1.2 mm, and a length of 500 mm was placed in a gear oven (60 UL manufactured by Toyo Seiki Co., Ltd.), heated at a temperature of 200 ° C., and the time until the vinyl chloride pipe turned black was measured. . Those that did not turn black for more than 60 minutes were considered acceptable.

The Examples using the copolymers (A-1) to (A-6) of the present invention all had a low heat deformation rate and an excellent appearance. On the other hand, in the comparative examples using the copolymers (B-1) to (B-6) that do not meet the conditions of the present invention and the chlorinated vinyl chloride resin, the case where the heat deformation rate becomes high or the appearance defect occurs. It was inferior to the Examples.

According to the present invention, by adding a vinyl chloride resin heat-resistant modifying copolymer to a vinyl chloride resin, it is possible to provide a molded article having excellent heat stability and excellent heat stability. In particular, it can be suitably used as a vinyl chloride pipe.

Claims (5)

Aromatic vinyl monomer unit 45-85 mass%, (meth) acrylic acid ester monomer unit 5-45 mass%, unsaturated dicarboxylic anhydride monomer unit 10-30 mass%, and copolymerizable Acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, N-methylmaleimide, N-ethylmaleimide, N-butylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-methylphenylmaleimide, N as vinyl monomers -At least one monomer unit selected from chlorophenylmaleimide (however, aromatic vinyl monomer unit, (meth) acrylic acid ester monomer unit, unsaturated dicarboxylic anhydride monomer unit and copolymerizable) consists a total to 100 wt% of vinyl monomer) the weight average molecular weight (Mw) of from 10 to 20 Resin composition vinyl resin heat modifying copolymer 5 to 50 mass% chloride consists 50 to 95 wt% vinyl chloride resin is. The resin composition according to claim 1, wherein a vinyl chloride resin heat-modifying copolymer having a melt mass flow rate (MFR) measured at 220 ° C. under a 98 N load of 0.5 to 20.0 g / min is used. The resin composition of Claim 1 or Claim 2 using the copolymer for a vinyl chloride resin heat-resistant modification whose Vicat softening temperature measured by 50N load is 110-150 degreeC. The molded object which consists of a resin composition of Claim 3. A vinyl chloride pipe comprising the resin composition according to claim 3.