JP2006160912A - Production process of vinyl chloride-based resin and vinyl chloride-based resin molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a production process of a vinyl chloride-based resin which hardly has an irregular structure and has excellent crystallinity, little yellowing caused by molding and excellent transparency and also to provide a molded product of the above vinyl chloride-based resin. <P>SOLUTION: The production process of the vinyl chloride-based resin comprises polymerizing vinyl chloride monomers and/or monomers copolymerizable with vinyl chloride in the presence of an aluminum-containing compound, a metallocene-based compound containing a transition metal of the group 4 in the periodic table and a radical polymerization inhibitor. The vinyl chloride-based resin molded product is prepared by molding the above resin. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a vinyl chloride resin and a vinyl chloride resin molded article.

Conventionally, a vinyl chloride resin has been used in many applications as a material having excellent properties such as mechanical strength, heat resistance, flame retardancy, weather resistance, chemical resistance, moisture absorption resistance, and transparency. .
However, the vinyl chloride resin has the disadvantage that, during thermoforming, the dehydrochlorination reaction takes place based on the unstable structure in the resin, resulting in yellowing due to double bonds. And unsuitable for applications requiring a light color.

  This is due to irregular structures such as branched structures and head-to-head structures, which are included in general vinyl chloride resins. By reducing this irregular structure, it is lower than general vinyl chloride resins. A vinyl chloride resin that is yellowed and generates less hydrogen chloride is expected.

  Various methods have been proposed to eliminate the above drawbacks. For example, a polymerization method for lowering the reaction temperature during the polymerization reaction (for example, see Patent Document 1) and a polymerization method using a metallocene compound (for example, Patent Document) 2) has been proposed.

JP-A-35-7588 JP 2002-80518 A

  However, the vinyl chloride resin obtained by the above polymerization method has a less irregular structure than a general vinyl chloride resin, but radicals are generated due to the polymerization conditions and the influence of impurities in the raw material, and the resin is not stable. Since a regular structure is generated, there has been no polymerization method capable of providing a vinyl chloride resin having no irregular structure stably.

  The present invention has been made in view of the above-described problems of the prior art, and has a method for producing a vinyl chloride resin having less irregular structure, excellent crystallinity, less yellowing during molding, and excellent transparency, and its chlorination. It aims at providing a vinyl-type resin molding.

  The method for producing a vinyl chloride resin according to claim 1 is a method comprising producing a vinyl chloride monomer and / or an aluminum-containing compound, a metallocene compound containing a transition metal of Group 4 of the periodic table, and a radical polymerization inhibitor. It is characterized by polymerizing a monomer copolymerizable with vinyl chloride.

  The method for producing a vinyl chloride resin according to claim 2 is the method for producing a vinyl chloride resin according to claim 1, wherein the aluminum-containing compound is an alkylaluminoxane.

  The method for producing a vinyl chloride resin according to claim 3 is the method for producing a vinyl chloride resin according to claim 1 or 2, wherein the metallocene compound containing a transition metal of Group 4 of the periodic table is a half titanocene. It is a system compound.

  The method for producing a vinyl chloride resin according to claim 4 is the method for producing a vinyl chloride resin according to any one of claims 1 to 3, wherein the radical polymerization inhibitor is N-nitrosophenylhydroxylamine. It is characterized by that.

  The vinyl chloride resin molded body according to claim 5 is formed by molding a vinyl chloride resin obtained by the production method according to any one of claims 1 to 4.

  Hereinafter, the present invention will be described in detail.

  The vinyl chloride resin in the present invention is a (co) polymer obtained by polymerizing or copolymerizing a vinyl chloride monomer and / or a monomer copolymerizable with vinyl chloride.

  The monomer copolymerizable with vinyl chloride may be any known vinyl monomer, for example, α-olefins such as ethylene, propylene and butylene: vinyl esters such as vinyl acetate and vinyl propionate: ethyl vinyl ether And vinyl ethers such as butyl vinyl ether: (meth) acrylic acid esters such as methyl (meth) acrylate, butyl (meth) acrylate, and hydroxyethyl (meth) acrylate. These may be used alone or in combination of two or more.

  Examples of the aluminum-containing compound include alkylaluminums such as trimethylaluminum, triethylaluminum, and tributylaluminum; and polyalkylaluminoxanes such as polymethylaluminoxane, polyethylaluminoxane, and polybutylaluminoxane. Aluminoxane is preferable in terms of small variation in quality after polymerization.

  Examples of the metallocene compound containing a transition metal belonging to Group 4 of the periodic table include titanocene compounds such as bis (cyclopentadienyl) titanium dichloride and bis (cyclopentadienyl) titanium dimethyl; Zirconium compounds such as enyl) zirconium dichloride and bis (cyclopentadienyl) zirconium dimethyl; cyclopentadienyl titanium trichloride, cyclopentadienyl titanium trimethoxide, cyclopentadienyl titanium tributoxide, cyclopentadienyl Titanium triphenoxide, pentamethylcyclopentadienyl titanium trimethoxide, pentamethylcyclopentadienyl titanium tributoxide, pentamethylcyclopentadienyl titania Triphenoxide, cyclopentadienyl (phenoxide) titanium dichloride, cyclopentadienyl (phenoxide) titanium dimethyl, pentamethylcyclopentadienyl (phenoxide) titanium dichloride, pentamethylcyclopentadienyl (phenoxide) titanium Half titanocene compounds such as dimethyl; cyclopentadienyl zirconium trichloride, cyclopentadienyl zirconium trimethoxide, cyclopentadienyl zirconium tributoxide, cyclopentadienyl zirconium triphenoxide, pentamethylcyclopentadienyl zirconium tri Methoxide, pentamethylcyclopentadienyl zirconium tributoxide, pentamethylcyclopentadienyl zirconium Nitriphenoxide, cyclopentadienyl (phenoxide) zirconium dichloride, cyclopentadienyl (phenoxide) zirconium dimethyl, pentamethylcyclopentadienyl (phenoxide) zirconium dichloride, pentamethylcyclopentadienyl (phenoxide) A half zirconocene compound such as zirconium dimethyl is exemplified, but a half titanocene compound is preferable in consideration of polymerization activity and economical aspect.

  Examples of the radical polymerization inhibitor include hydroquinone, tert-butylhydroquinone, paramethoxyphenol, 2,4-dinitrophenol, tert-butylcatechol, N-methyl-N-nitrosoaniline, N-nitrosophenylhydroxylamine, N -Nitrosophenylhydroxylamine ammonium salt, 2,2,6,6-tetramethylpiperidinooxy free radicals (hereinafter also referred to as TEMPO), etc. Nitrosophenylhydroxylamine (hereinafter also referred to as NFHA) is preferred.

The concentration of the metallocene compound containing a transition metal of Group 4 of the Periodic Table in the polymerization system is not particularly limited, but the transition metal concentration is preferably in the range of 10 ⁻¹ to 10 ⁻⁸ mol / l. 10 -1 ^{mol /} less than l to be obtained easily problems molecular weight decreases and the residual metal content increases vinyl chloride resin occurs sometimes 10 -8 exceeding ^{mol /} l and the polymerization efficiency decreases problems.

The concentration of the aluminum-containing compound, in a molar ratio of transition metal atom of the metallocene compound, it is preferred molar ratio of aluminum / transition metal atom is in the range of 10 to 10 ^5. Molar ratio tends to occur a problem of polymerization yield decreases to be less than 10, the molar ratio and the problem of residual metal amount increase occurs exceeds 10 ^5.

The concentration of the radical inhibitor is preferably in the range of 10 to 10 ⁶ ppm relative to the total amount of vinyl chloride monomer and / or monomer copolymerizable with vinyl chloride. If it is less than 10 ppm, the problem of radical merging tends to occur, and if it exceeds 10 ⁶ ppm, problems such as coloring of the obtained vinyl chloride resin may occur.

  In addition, the polymerization temperature is not particularly limited, but if the reaction temperature is lowered, the reaction rate is slowed down, and it takes time to polymerize to a predetermined yield. If the polymerization temperature is increased, the reaction pressure is increased, and high pressure resistance is required. Therefore, it is preferably in the range of −30 ° C. to 60 ° C. There is no particular limitation on the reaction pressure.

  Moreover, it does not specifically limit as a polymerization method of this invention, For example, polymerization reaction, such as block polymerization and solution polymerization, can be performed. The solvent for solution polymerization is not particularly limited, but a solvent that does not denature during the polymerization is selected. For example, dichloromethane, benzene, toluene and the like can be mentioned. Of these, toluene is particularly preferable because it can be easily deashed and washed after polymerization.

  In carrying out the present invention, a vinyl chloride monomer and / or a monomer copolymerizable with a vinyl chloride monomer, an aluminum-containing compound, a metallocene compound, a radical are placed in a reaction vessel under an inert gas atmosphere such as nitrogen or argon. A polymerization inhibitor and optionally a solvent are added to initiate the polymerization reaction. In addition to the reactor, it may be dissolved or diluted with a solvent or the like.

  The vinyl chloride resin molded product of the present invention is formed by molding a vinyl chloride resin obtained by using the above-described method for producing a vinyl chloride resin.

  As the method for molding a molded body from the above-mentioned vinyl chloride resin, any conventionally known method can be adopted, for example, extrusion molding method, injection molding method, blow molding method, roll molding method, calendar molding method, press molding method, etc. Is mentioned.

  When molding a molded body from the above-mentioned vinyl chloride resin, a compounding agent generally added when producing a vinyl chloride resin molded body, for example, a heat stabilizer, a heat stabilization aid, as necessary. Agents, lubricants, processing aids, impact modifiers, heat resistance improvers, antioxidants, light stabilizers, ultraviolet absorbers, pigments, plasticizers and the like.

  The heat stabilizer is not particularly limited as long as it is a heat stabilizer used in molding a vinyl chloride resin. For example, dimethyltin mercapto, dibutyltin mercapto, dioctyltin mercapto, dibutyltin malate, Organotin stabilizers such as dibutyltin malate polymer, dioctyltin malate, dioctyltin malate polymer, dibutyltin laurate, dibutyltin laurate polymer, lead stearate, dibasic lead phosphite, tribasic lead sulfate Lead stabilizers such as calcium-zinc stabilizers, barium-zinc stabilizers, barium-cadmium stabilizers, and the like. These may be used alone or in combination of two or more.

  The stabilizing aid is not particularly limited as long as it is a stabilizing aid used in molding a vinyl chloride resin, for example, epoxidized soybean oil, epoxidized linseed oil, epoxidized tetrahydrophthalate, Examples include epoxidized polybutadiene and phosphate esters. These may be used alone or in combination of two or more.

  Examples of the lubricant include an internal lubricant and an external lubricant used when molding a vinyl chloride resin composition.

  The internal lubricant is a lubricant added for the purpose of reducing the flow viscosity of the molten resin during thermoforming and preventing frictional heat generation. For example, lauryl alcohol, stearyl alcohol, stearic acid, butyl stearate, glycerin monostearate is used. Rate, epoxidized soybean oil, bisamide and the like. These may be used alone or in combination of two or more.

  The external lubricant is a lubricant added for the purpose of enhancing the sliding effect between the molten resin and the mold surface during thermoforming, and examples thereof include montanic acid wax, paraffin wax, polyethylene wax, and ester wax. These may be used alone or in combination of two or more.

  The processing aid is not particularly limited as long as it is a processing aid used when molding a vinyl chloride resin. For example, an alkyl acrylate-alkyl methacrylate copolymer having a weight average molecular weight of 100,000 to 2,000,000 is used. Examples include acrylic processing aids that are coalesced, and specific examples include n-butyl acrylate-methyl methacrylate copolymer, 2-ethylhexyl acrylate-methyl methacrylate-butyl methacrylate copolymer, and the like. These may be used alone or in combination of two or more.

  The impact modifier is not particularly limited as long as it is an impact modifier used when molding a vinyl chloride resin. For example, methyl methacrylate-butadiene-styrene copolymer (MBS resin), chlorination Examples include polyethylene and acrylic rubber. These may be used alone or in combination of two or more.

  The heat resistance improver is not particularly limited as long as it is an impact improver used when molding a vinyl chloride resin. For example, a heat improver such as α-methylstyrene or N-phenylmaleimide Is mentioned. These may be used alone or in combination of two or more.

  The antioxidant is not particularly limited as long as it is an antioxidant used when molding a vinyl chloride resin, and examples thereof include a phenolic antioxidant. These may be used alone or in combination of two or more.

  The light stabilizer is not particularly limited as long as it is a light stabilizer used when molding a vinyl chloride resin, and examples thereof include hindered amine light stabilizers. These may be used alone or in combination of two or more.

  The ultraviolet absorber is not particularly limited as long as it is a light stabilizer used when molding a vinyl chloride resin, and examples thereof include salicylic acid ester, benzophenone, benzotriazole, and cyanoacrylate. An ultraviolet absorber is mentioned. These may be used alone or in combination of two or more.

  The pigment is not particularly limited as long as it is a pigment used when molding a vinyl chloride resin. For example, organic pigments such as azo, phthalocyanine, selenium, and dye lake, and oxides Inorganic pigments such as molybdenum chromate, sulfide / selenide, ferrocyanide, and the like. These may be used alone or in combination of two or more. In addition, when transparency is calculated | required by a molded object, it is necessary to add in consideration of the required transparency.

  The plasticizer is added for the purpose of improving the melt resin and processability during thermoforming, and is not particularly limited as long as it is a plasticizer used when molding a vinyl chloride resin. For example, dibutyl phthalate, di-2-ethylhexyl phthalate, di-2-ethylhexyl adipate and the like can be mentioned. These may be used alone or in combination of two or more.

  The method of mixing the above-mentioned compound and the vinyl chloride resin is not particularly limited, and examples thereof include a hot blend method and a cold blend method.

  According to the present invention, as described above, in the presence of an aluminum-containing compound, a metallocene compound containing a transition metal of Group 4 of the periodic table, and a radical polymerization inhibitor, vinyl chloride monomer and / or vinyl chloride and Since a copolymerizable monomer is polymerized, it is possible to provide a method for producing a vinyl chloride resin having less irregular structure and excellent crystallinity.

  Although the mechanism of action for reducing the irregular structure is not necessarily clear, even if radicals are generated due to the influence of impurities, solvents, etc. in the polymerization system, it is possible to suppress the simultaneous occurrence of radical polymerization by quickly capturing them. Presumed.

  Therefore, according to the present invention, it is possible to provide a method for producing a vinyl chloride resin that is less yellowed during molding and excellent in transparency, and a molded body of the vinyl chloride resin.

  When the aluminum-containing compound is an alkylaluminoxane, the above effect is further ensured.

  Further, when the metallocene compound containing a transition metal of Group 4 of the periodic table is a half titanocene compound, the polymerization activity is improved and the economical aspect is improved, and the above effect is further ensured. .

  Further, when the radical polymerization inhibitor is N-nitrosophenylhydroxylamine, the coloring property is improved with a small addition amount, and the above effect is further ensured.

  Since the vinyl chloride resin molded product of the present invention is formed by molding the vinyl chloride resin obtained as described above, it has the same effect as described above, has little yellowing and has excellent transparency. It becomes.

  Examples of the present invention will be described below, but the present invention is not limited to the following examples.

Example 1
Hot water at 70 ° C. was passed through the jacket of a 15 liter jacketed autoclave, the inside of the autoclave was decompressed with a vacuum pump for 30 minutes, sufficiently dehydrated and dried, and then cooled to room temperature. After cooling, in an autoclave under reduced pressure, 450 ml of a 10 wt% toluene solution of pentamethylcyclopentadienyl tributoxide, 450 ml of a 10 wt% toluene solution of polymethylaluminoxane, and 10 wt% toluene of N-nitrosophenylhydroxylamine After 100 ml of the solution was sequentially injected through a rubber stopper with a syringe, 9 kg of vinyl chloride monomer sufficiently dehydrated with a molecular sieve was injected, and the temperature was adjusted to 20 ° C. and anion polymerization was performed for 48 hours.

  After completion of the polymerization, unreacted vinyl chloride monomer is discharged from the autoclave, methyl alcohol is supplied to deactivate the reaction, and then the polymer is taken out from the polymerization vessel. Filtration and washing were repeated, followed by dehydration and drying to obtain a powdered vinyl chloride resin.

(Example 2)
Hot water at 70 ° C. was passed through the jacket of a 15 liter jacketed autoclave, the inside of the autoclave was decompressed with a vacuum pump for 30 minutes, sufficiently dehydrated and dried, and then cooled to room temperature. After cooling, in an autoclave under reduced pressure, 450 ml of a 10 wt% toluene solution of pentamethylcyclopentadienyl trimethoxide, 450 ml of a 10 wt% toluene solution of polymethylaluminoxane, 10 wt% toluene of N-nitrosophenylhydroxylamine After 100 ml of the solution was sequentially injected through a rubber stopper with a syringe, 9 kg of vinyl chloride monomer sufficiently dehydrated with a molecular sieve was injected, and the temperature was adjusted to 20 ° C. and anion polymerization was performed for 48 hours.

  After completion of the polymerization, unreacted vinyl chloride monomer is discharged from the autoclave, methyl alcohol is supplied to deactivate the reaction, and then the polymer is taken out from the polymerization vessel. Filtration and washing were repeated, followed by dehydration and drying to obtain a powdered vinyl chloride resin.

(Example 3)
Hot water at 70 ° C. was passed through the jacket of a 15 liter jacketed autoclave, the inside of the autoclave was decompressed with a vacuum pump for 30 minutes, sufficiently dehydrated and dried, and then cooled to room temperature. After cooling, in a vacuum autoclave, sequentially add 450 ml of a 10 wt% toluene solution of pentamethylcyclopentadienyltributoxide, 450 ml of a 10 wt% toluene solution of polymethylaluminoxane, and 100 ml of a 10 wt% toluene solution of TEMPO in order. After injecting through a rubber stopper, 9 kg of vinyl chloride monomer sufficiently dehydrated with molecular sieves was injected, adjusted to 20 ° C. and polymerized for 48 hours.

  After completion of the polymerization, unreacted vinyl chloride monomer is discharged from the autoclave, methyl alcohol is supplied to deactivate the reaction, and then the polymer is taken out from the polymerization vessel. Filtration and washing were repeated, followed by dehydration and drying to obtain a powdered vinyl chloride resin.

Example 4
Hot water at 70 ° C. was passed through a 15 liter jacketed autoclave jacket, the inside of the autoclave was depressurized with a vacuum pump for 3 hours, sufficiently dehydrated and dried, and then cooled to room temperature. After cooling, 7 kg of sufficiently dehydrated toluene was supplied to the autoclave, and then 100 ml of a 10 wt% toluene solution of pentamethylcyclopentadienyltriphenoxide, 100 ml of a 10 wt% toluene solution of polymethylaluminoxane, N- 100 ml of a 10% by weight toluene solution of nitrosophenylhydroxylamine was sequentially injected through a rubber stopper with a syringe, and then 2 kg of vinyl chloride monomer sufficiently dehydrated with a molecular sieve was injected, and the temperature was adjusted to 20 ° C. and polymerized for 48 hours.

  After completion of the polymerization, unreacted vinyl chloride monomer is discharged from the autoclave, methyl alcohol is supplied to deactivate the reaction, and then the polymer is taken out from the polymerization vessel. Filtration and washing were repeated, followed by dehydration and drying to obtain a powdered vinyl chloride resin.

(Comparative Example 1)
Hot water at 70 ° C. was passed through the jacket of a 15 liter jacketed autoclave, the inside of the autoclave was decompressed with a vacuum pump for 30 minutes, sufficiently dehydrated and dried, and then cooled to room temperature. After cooling, 450 ml of a 10 wt% toluene solution of pentamethylcyclopentadienyl tributoxide and 450 ml of a 10 wt% toluene solution of polymethylaluminoxane are sequentially injected through a rubber stopper with a syringe into an autoclave under reduced pressure, and then a molecular sieve. Then, 9 kg of vinyl chloride monomer dehydrated sufficiently was injected, adjusted to 20 ° C., and anionic polymerization was performed for 48 hours.

  After completion of the polymerization, unreacted vinyl chloride monomer is discharged from the autoclave, methyl alcohol is supplied to deactivate the reaction, and then the polymer is taken out from the polymerization vessel. Filtration and washing were repeated, followed by dehydration and drying to obtain a powdered vinyl chloride resin.

(Comparative Example 2)
A 50-liter jacketed stainless steel polymerization vessel equipped with a stirrer and a reflux condenser was degassed, and steam was blown from the reflux condenser to raise the temperature inside the polymerization vessel to 80 ° C., and deionization at 50 ° C. 25,000 g of water, 10 g of partially saponified polyvinyl alcohol, 5 g of hydroxypropylmethylcellulose and 6 g of di-2-ethylhexyl peroxydicarbonate were supplied and stirred.

  While stirring, 15,000 g of vinyl chloride monomer was supplied, and the temperature was raised to 57 ° C. to carry out water suspension radical polymerization. When the temperature in the polymerization reactor reached 57 ° C, the operation of the reflux condenser was started, and the temperature in the polymerization reactor was maintained at 57 ° C.

  When the pressure in the polymerization vessel drops to 0.2 MPa, nitrogen gas is supplied to remove unreacted chlorine vinyl monomer, and the resulting resin is washed with deionized water, dehydrated and dried to form a powder. Of vinyl chloride resin was obtained.

(Physical property measurement)
Using the obtained vinyl chloride resin, the chlorine content, the amount of generated hydrogen chloride, and the yellowness YI were measured, and the results are shown in Table 1.

  In addition, a plate-shaped test piece was prepared using the obtained vinyl chloride resin, and the total light transmittance, haze, yellowness and water absorption were measured, and the results are shown in Table 1. In addition, the preparation method and each measuring method of a plate-shaped test piece were as follows.

(1) Amount of generated hydrogen chloride 1 g of the obtained vinyl chloride resin is supplied to a test tube, sealed with a heat-resistant rubber stopper with a tube, and immersed in a 180 ° C. oil bath from the bottom 2/3 and heated. did. The gas generated from the test tube was collected with 100 ml of ion exchange water through the tube for 20 minutes. The pH of ion exchange water was measured 20 minutes after the start of collection, and the amount of hydrogen chloride generated was calculated from the difference from the pH of ion exchange water before the start of collection. The unit is ppm.

(2) Resin press yellowness YI
The obtained powdered vinyl chloride resin is supplied to a press molding machine (manufactured by Yasuda Seiki Seisakusho Co., Ltd.) set at 170 ° C., preheated for 1 minute, pressed at 200 MPa for 1 minute, and has a thickness of 1 mm. A 5 cm square plate-like body was prepared. Next, the obtained plate-like body was supplied to a handy color difference meter (manufactured by Nippon Denshoku Industries Co., Ltd., trade name “NR-3000”) and measured according to JIS K7105.

(3) Preparation of vinyl chloride resin plate test piece 100 parts by weight of the obtained vinyl chloride resin or vinyl chloride-vinylidene chloride copolymer, organotin stabilizer (trade name “ONZ, manufactured by Sansha Co., Ltd.) −7F ”) and 2 parts by weight of lubricant (Mitsubishi Rayon Co., Ltd., trade name“ METABBRENE P-710 ”) were mixed by stirring to obtain a resin composition.

  The obtained resin composition was supplied to an 8-inch mixing roll (manufactured by Yasuda Seisakusho Co., Ltd.), wound at 170 ° C. and kneaded for 30 seconds to obtain a sheet-like material. And preheated at 180 ° C. for 2 minutes, pressed at 200 MPa for 2 minutes, and cooled to obtain plate-shaped test pieces having a thickness of 1 mm and 3 mm.

(4) Total light transmittance A 3 mm thick, 50 mm square plate-shaped test piece was supplied to a turbidimeter (manufactured by Nippon Denshoku Industries Co., Ltd., trade name “NDH-2000”) and measured according to JIS K7361. . The unit is%.

(5) Haze A 3 mm thick, 50 mm square plate-shaped test piece was supplied to a turbidimeter (manufactured by Nippon Denshoku Industries Co., Ltd., trade name “NDH-2000”) and measured according to JIS K7136. The unit is%.

(6) Yellowness (YI)
A plate test piece having a thickness of 3 mm and a square of 50 mm was supplied to a handy color difference meter (trade name “NR-3000” manufactured by Nippon Denshoku Industries Co., Ltd.) and measured according to JIS K7105.

(7) Water absorption rate Using a plate test piece having a thickness of 1 mm and a 50 mm square, the water absorption rate after being immersed in distilled water at 23 ° C for 24 hours was measured in accordance with JIS K7209. The unit is%.

  As is clear from Table 1, in the examples of the present invention, the occurrence of dehydrochlorination reaction during thermoforming is suppressed, the material is low yellowing, and the molded product has little yellowing and excellent transparency. There was found.

Claims (5)

  Polymerizing a vinyl chloride monomer and / or a monomer copolymerizable with vinyl chloride in the presence of an aluminum-containing compound, a metallocene compound containing a transition metal of Group 4 of the periodic table, and a radical polymerization inhibitor A method for producing a vinyl chloride resin.   The method for producing a vinyl chloride resin according to claim 1, wherein the aluminum-containing compound is an alkylaluminoxane.   The method for producing a vinyl chloride resin according to claim 1 or 2, wherein the metallocene compound containing a transition metal of Group 4 of the periodic table is a half titanocene compound.   The method for producing a vinyl chloride resin according to any one of claims 1 to 3, wherein the radical polymerization inhibitor is N-nitrosophenylhydroxylamine.   A vinyl chloride resin molded article obtained by molding a vinyl chloride resin obtained by the production method according to any one of claims 1 to 4.