JP2011246511A - Method for manufacturing vinyl chloride-based polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a vinyl chloride-based polymer being excellent in molding processability represented by a gelling property, draw down property, flowability as a powder, a handling property or the like since it has a graft copolymerization structure.SOLUTION: The method for manufacturing the vinyl chloride-based polymer includes Step (I): a step for obtaining vinyl chloride-based macro-initiator (C) by performing suspension polymerization of specific monomer (A) and vinyl chloride monomer (B) in the presence of a radical polymerization initiator and a dispersing agent in a water-based medium and Step (II): a step for manufacturing the vinyl chloride-based polymer by performing graft copolymerization of the vinyl chloride-based macro-initiator (C) obtained in Step (I) and at least one monomer (D) selected from the group consisting of alkyl acrylates, alkyl methacrylates and vinyl carboxylate in the presence of a living radical polymerization catalyst and a dispersing agent in a water-based medium.

Description

  The present invention relates to a method for producing a vinyl chloride polymer, and more particularly to a method for producing a vinyl chloride polymer having excellent molding processability and having a graft copolymer structure.

  Conventionally, with improvement in productivity, cost reduction, and energy saving, a vinyl chloride resin with higher workability capable of high speed processing, thin wall processing, low temperature processing, and the like has been desired. The processability of general vinyl chloride resins, especially so-called hard vinyl chloride resins, is mainly governed by the resin melting process (gelation characteristics) and the fluidity of the molten state (flow characteristics). As widely improving processability, for example, a hard vinyl chloride resin composition in which a higher fatty acid ester of pentaerythritol or dipentaerythritol is mixed as a lubricant with a vinyl chloride homopolymer has been proposed (see, for example, Patent Documents 1 to 3). .)

  In addition, vinyl chloride with excellent processability is obtained by suspension polymerization of alkyl acrylate and / or alkyl methacrylate using a radical polymerization initiator and a dispersant in the presence of vinyl chloride homopolymer in an aqueous solvent. A method for producing a polymer is proposed (see, for example, Patent Document 4).

Japanese Patent Publication No. 55-017054 (Claims) Japanese Patent Publication No. 51-020209 (Claims) JP 53-006350 A (Claims) JP 62-001712 A (Claims)

  However, in the resin compositions proposed in Patent Documents 1 to 3, since the lubricity is imparted between the processing machine and the resin composition, the driving power of the processing machine is reduced, but the effect of improving the gelling property is There was a problem that the gelation was not sufficient and delayed.

  Further, the vinyl chloride polymer obtained by the method proposed in Patent Document 4 is a plasticized vinyl chloride resin and improved gelation properties, but the resulting resin has a low melt viscosity and melt tension, and is molded. There are issues such as the occurrence of drawdown during processing, deterioration of dimensional stability during extrusion molding, poor foaming during foam molding, deterioration of thickness uniformity during blow / vacuum molding, and generation of air marks during calendar molding. It was a thing.

  Therefore, an object of the present invention is to provide a method for producing a vinyl chloride polymer having excellent gelling properties and good workability without reducing melt viscosity more than necessary.

  As a result of intensive studies to solve the above problems, the present inventors have found that a vinyl chloride polymer having a graft structure has excellent gelling properties and good workability without lowering the melt viscosity more than necessary. The present invention has been completed by finding a novel vinyl chloride polymer and a novel method for producing the vinyl chloride polymer.

That is, this invention relates to the manufacturing method of the vinyl chloride polymer characterized by passing through following process (I) and process (II).
Step (I): Monomer (A) and vinyl chloride monomer (B) represented by the following general formula (1) are subjected to suspension polymerization in an aqueous medium in the presence of a radical polymerization initiator and a dispersant. The process of performing and obtaining a vinyl chloride macroinitiator (C).

（１）
（式中、Ｘ^１は塩素原子、臭素原子またはヨウ素原子であり、Ｒ^１およびＲ^２は各々独立して水素原子、炭素数１〜５の炭化水素基であり、ｎは０〜５の整数である。）
工程（ＩＩ）；工程（Ｉ）で得られた塩化ビニル系マクロ開始剤（Ｃ）と、アクリル酸アルキルエステル，メタクリル酸アルキルエステル及びカルボン酸ビニルからなる群から選ばれる少なくとも１種の単量体（Ｄ）とを、リビングラジカル重合触媒および分散剤の存在下、水性媒体中でグラフト共重合を行い、塩化ビニル系重合体を製造する工程。

(1)
(In the formula, X ¹ is a chlorine atom, a bromine atom or an iodine atom, R ¹ and R ² are each independently a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms, and n is an integer of 0 to 5) .)
Step (II); at least one monomer selected from the group consisting of the vinyl chloride macroinitiator (C) obtained in Step (I) and an alkyl acrylate, alkyl methacrylate and vinyl carboxylate A step of producing a vinyl chloride polymer by performing graft copolymerization with (D) in an aqueous medium in the presence of a living radical polymerization catalyst and a dispersant.

  Below, the manufacturing method of the vinyl chloride polymer of this invention is demonstrated in detail.

  The present invention is a method for producing a vinyl chloride polymer obtained through the steps (I) and (II).

  Here, in the step (I), the monomer (A) and the vinyl chloride monomer (B) represented by the general formula (1) are mixed in an aqueous medium in the presence of a radical polymerization initiator and a dispersant. In this step, suspension polymerization is performed to obtain a vinyl chloride macroinitiator (C).

The monomer (A) is a compound belonging to the category of the general formula (1), and X ¹ is a chlorine atom, a bromine atom or an iodine atom. R ¹ and R ² are each independently a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms, and n is an integer of 0 to 5. Here, examples of R ¹ and R ² include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, and an isopentyl group. In addition, n is preferably an integer of 0 or 1 because it is particularly excellent in copolymerizability with the vinyl chloride monomer (B).

  The monomer (A) is a monomer that can be copolymerized with a vinyl chloride monomer by suspension polymerization in an aqueous medium in the presence of a radical polymerization initiator and a dispersant, such as vinyl chloroacetate. , Vinyl bromoacetate, vinyl iodoacetate, vinyl-2-chloroisobutyrate, vinyl-2-bromoisobutyrate, vinyl-2-iodoisobutyrate, allyl-2-chloroacetate, allyl-2-bromoacetate, Allyl-2-iodoacetate, allyl-2-chloropropionate, allyl-2-bromopropionate, allyl-2-iodopropionate, allyl-2-chloroisobutyrate, allyl-2-bromoisobutyrate Rate, allyl-2-iodoisobutyrate, and the like. Among them, in particular, in step (II), the living monomer of monomer (D) is used. Since cal polymerization proceeds efficiently, allyl-2-chloropropionate, allyl-2-bromopropionate, allyl-2-iodopropionate, allyl-2-chloroisobutyrate, allyl-2 -Bromoisobutyrate and allyl-2-iodoisobutyrate are preferable, and allyl-2-bromoisobutyrate and allyl-2-iodoisobutyrate are more preferable.

  The monomer (A) is preferably used in an amount of 0.001 to 5 parts by weight per 100 parts by weight of the vinyl chloride monomer (B).

  The radical polymerization initiator used in the step (I) is any radical polymerization initiator that can initiate copolymerization of the monomer (A) and the vinyl chloride monomer (B) in suspension polymerization. For example, cumyl peroxyneodecanoate, tert-hexylperoxyneodecanoate, tert-butylperoxyneodecanoate, tert-hexylperoxypivalate, tert-butylperoxypivalate, etc. Perester type initiators; dicarbonate type initiators such as di-sec-butyl peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate; isobutyryl peroxide, 3,5,5-trimethylhexanoyl peroxide, Lauro Diacyl type initiators such as ruperoxide; azo type initiators such as 2,2′-azobisisobutyronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile; potassium persulfate, ammonium persulfate, etc. A water-soluble initiator etc. can be mentioned, These radical polymerization initiators can be used by 1 or more types.

  The radical polymerization initiator is preferably used in an amount of 0.001 to 1 part by weight per 100 parts by weight of the vinyl chloride monomer (B).

  As the dispersing agent used in the step (I), any dispersing agent capable of dispersing the monomer (A) and the vinyl chloride monomer (B) in suspension polymerization can be used. Examples include organic substances such as methyl cellulose, ethyl cellulose, hydroxypropyl methyl cellulose, hydroxymethyl cellulose, polyvinyl alcohol and partially saponified products thereof, gelatin, polyvinyl pyrrolidone and starch; inorganic substances such as magnesium carbonate, calcium carbonate and calcium phosphate, and the like. One or more agents can be used.

  The dispersant is preferably used in an amount of 0.01 to 1 part by weight per 100 parts by weight of the vinyl chloride monomer (B), and a vinyl chloride macroinitiator (C) having a particularly excellent particle form is obtained. Is preferably 0.05 to 0.2 parts by weight.

  Examples of the aqueous medium used in the step (I) include water, ion exchange water, distilled water, deionized water, industrial water, drinking water, and the like. For example, suspension polymerization of an organic solvent such as alcohol is performed. It may be included within a range where there is no problem. The aqueous medium may be used in any amount as long as suspension polymerization is possible, and since vinyl chloride macroinitiator (C) can be produced particularly efficiently, vinyl chloride is used. It is preferable that it is 100-500 weight part with respect to 100 weight part of monomers (B).

  The polymerization temperature in the step (I) may be any temperature as long as suspension copolymerization of the monomer (A) and the vinyl chloride monomer (B) is possible. Since it becomes possible to obtain efficiently the vinyl chloride macroinitiator (C) which has this, it is preferable that it is 0 to 100 degreeC, and it is especially preferable that it is 40 to 70 degreeC.

  The vinyl chloride macroinitiator (C) obtained by the step (I) is a copolymer obtained by copolymerizing the monomer (A) and the vinyl chloride monomer (B), Since the monomer (A) residue is contained as a copolymerization component, it acts as a macroinitiator having a radical polymerization ability of a vinyl monomer. The vinyl chloride macroinitiator (C) may be any one as long as it has a living radical polymerization ability in the step (II) to be described later, and the vinyl chloride polymer obtained among them is particularly preferred. It is preferable that the following (i) to (iii) are satisfied because the molding processability is excellent. i) Number average molecular weight (hereinafter referred to as Mn) measured by gel permeation chromatography (hereinafter referred to as GPC) is 20,000 to 200,000, ii) Weight average molecular weight measured by GPC (hereinafter referred to as GPC) Mw / Mn expressed by the ratio of Mw) to Mn is 1 to 5, iii) the copolymerization composition (mol%) of the residue of the monomer (A) is 0.001 to 10 .

  In addition, the vinyl chloride macroinitiator (C) has excellent handleability in the step (II), and in particular, can produce a vinyl chloride polymer having excellent powder flowability and bulk specific gravity. It is preferable that the average particle diameter is 50 to 500 μm.

  Step (II) in the present invention is at least one selected from the group consisting of the vinyl chloride macroinitiator (C) obtained in step (I), alkyl acrylate, alkyl methacrylate and vinyl carboxylate. This is a step of producing a vinyl chloride polymer by performing graft copolymerization of the seed monomer (D) in an aqueous medium in the presence of a living radical polymerization catalyst and a dispersant. Here, the vinyl chloride macroinitiator (C) obtained by the step (I) may be used as the suspension obtained by the step (I), or the vinyl chloride macroinitiator is obtained from the suspension. The agent (C) may be isolated and used.

  The monomer (D) used in the step (II) is at least one monomer selected from the group consisting of alkyl acrylate, alkyl methacrylate and vinyl carboxylate, and the alkyl acrylate As, for example, acrylic acid methyl ester, acrylic acid ethyl ester, acrylic acid n-butyl ester, acrylic acid isobutyl ester, acrylic acid t-butyl ester, acrylic acid 2-ethylhexyl ester, acrylic acid lauryl ester, stearyl acrylic acid Examples include esters, tridecyl acrylate, benzyl acrylate, cyclohexyl acrylate, and the like. Examples of the methacrylic acid alkyl ester include methacrylic acid methyl ester, methacrylic acid ethyl ester, methacrylic acid n-butyl ester, methacrylic acid isobutyl ester, methacrylic acid t-butyl ester, methacrylic acid 2-ethylhexyl ester, methacrylic acid lauryl ester. , Methacrylic acid stearyl ester, methacrylic acid tridecyl ester, methacrylic acid benzyl ester, methacrylic acid cyclohexyl ester and the like. As vinyl carboxylate, for example, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate, vinyl myristate, vinyl palmitate, vinyl stearate, vinyl cyclohexanecarboxylate, Examples include vinyl pivalate, vinyl octylate, vinyl monochloroacetate, divinyl adipate, vinyl methacrylate, vinyl crotonate, vinyl sorbate, vinyl benzoate, and vinyl cinnamate. And since it becomes a vinyl chloride polymer with particularly excellent gelling properties and good processability, as the monomer (D), acrylic acid methyl ester, acrylic acid n-butyl ester, acrylic acid isobutyl ester, Acrylic acid t-butyl ester, methacrylic acid methyl ester, methacrylic acid n-butyl ester, methacrylic acid isobutyl ester, methacrylic acid t-butyl ester, and vinyl acetate are preferred.

  The monomer (D) is preferably used in an amount of 0.1 to 100 parts by weight with respect to 100 parts by weight of the vinyl chloride macroinitiator (C), and is particularly excellent in the balance between melt viscosity and gelling property. Since a vinyl polymer is obtained, it is preferable that it is 0.1-70 weight part.

  The living radical polymerization catalyst is a catalyst added for imparting a living radical polymerization ability to the residue portion of the monomer (A) contained in the vinyl chloride macroinitiator (C). Such living radical polymerization is described in, for example, Chem. Rev. 101, 3689 (2001); Chem. Rev. (2001), 101, 2921; Chem. rev. (2009), 5069, and the like.

As a method for producing a vinyl chloride graft polymer by a normal radical polymerization reaction, a method of polymerizing a monomer in the presence of a vinyl chloride resin, a method of polymerizing a vinyl chloride monomer in the presence of another resin However, there is a known problem that these polymerization methods produce many homopolymers and the graft copolymer cannot be produced efficiently. In the present invention, the step (I) After passing through the step, the graft copolymer can be efficiently produced by starting living radical polymerization from the C-X ¹ portion of the residue component of the monomer (A) in step (II). Is.

  Any living radical polymerization catalyst may be used as long as it belongs to the category of living radical polymerization catalyst. For example, Group 7, 8, 9, 10, or 11 of the periodic table can be used. The catalyst comprised from the metal or metal compound which has an element, and a ligand compound can be mentioned. When the living radical polymerization catalyst is used, it may be prepared from the metal or metal compound and the ligand compound in a step different from step (II), or the metal or metal compound and the coordination. Each of the child compounds may be added to step (II) and used as a living radical polymerization catalyst.

  Examples of metals or metal compounds having Group 7, 8, 9, 10, or 11 elements of the periodic table constituting the living radical polymerization catalyst include copper, iron, ruthenium, cobalt, rhodium, iridium, Nickel, palladium, platinum or a compound containing the same may be mentioned, and particularly copper, iron, ruthenium or a compound containing the same is preferable because the living radical polymerization efficiency is excellent, and zero-valent copper; cuprous chloride, Copper compounds such as cuprous bromide, cuprous iodide, cuprous cyanide, cuprous oxide, cuprous perchlorate; ruthenium compounds such as ruthenium chloride; iron compounds such as iron chloride In particular, zero-valent copper; copper halides such as cuprous chloride and cuprous bromide are preferred.

  Examples of the ligand compound constituting the living radical polymerization catalyst include a ligand compound containing a carbon compound that can be π-bonded to a nitrogen atom, an oxygen atom, a phosphorus atom, a sulfur atom, or a transition metal. 2′-bipyridyl, 4,4′-dimethyl-2,2′-bipyridyl, 4,4′-dinonyl-2,2′-bipyridyl, bis (2-pyridylmethyl) octadecylamine, 1,10-phenanthroline, etc. Cyclic amine derivatives; aliphatic amines such as tetramethylethylenediamine, pentamethyldiethylenetriamine, tris (2-aminoethyl) amine, hexamethyltris (2-aminoethyl) amine, polyethyleneimine; triphenylphosphine, cyclopentadiene, indene, etc. Especially, it is excellent in living radical polymerization efficiency Since the 4,4'-dinonyl-2,2'-bipyridyl, bis (2-pyridylmethyl) amine to introduce hydrophobic groups such as octadecylamine are preferred.

  In addition, as the living radical polymerization catalyst, a ligand compound having a nitrogen atom is preferable as a ligand compound when a catalyst composed of a copper compound and a ligand compound is used. Therefore, a ligand compound having a nitrogen atom into which a hydrophobic group typified by an alkyl chain having 1 to 18 carbon atoms is introduced is preferable because it can suppress and efficiently produce a vinyl chloride polymer. . Specifically, Chem. Rev. (2001), 101, 2921, Chem. Rev. (2007), 107, 2270; Chem. rev. (2009), 5069, etc., and a catalyst comprising a copper compound and a ligand compound can also be used. Furthermore, as a living radical polymerization catalyst, a metal compound and a ligand in the case of using a catalyst composed of a metal compound containing iron and ruthenium and a ligand compound are specifically described in Chem. Rev. 101, 3689 (2001); Chem. Rev. 109, 4963 (2009), and the like can be used.

  As the dispersant and aqueous medium in step (II), the dispersant and aqueous medium used in the above-described step (I) can be used. Moreover, as a dispersing agent in that case, it is preferable to use at 0.001-1 weight part per 100 weight part of this vinyl chloride macroinitiator (C).

  The polymerization temperature in the step (II) is preferably 0 to 100 ° C.

  Since the vinyl chloride polymer obtained by the production method of the present invention is a vinyl chloride polymer excellent in gelling property, drawdown property, fluidity as a powder, and handling property, the following iv) to vi) It is preferable that the above properties are satisfied. iv) Mn measured by GPC is 20000-200000. v) Mw / Mn measured by GPC is 1-10. vi) The residue component composition derived from the monomer (D) is 0.1 to 50% by weight, particularly 0.1 to 30% by weight, based on 100% by weight of each component.

Further, in order to obtain further excellent gelation property, drawdown property, fluidity as a powder, and handling property, a vinyl chloride polymer satisfying the following properties vii) to ix) is preferable. vii) It has a particle shape. viii) The average particle size is 50-700 μm. ix) The bulk specific gravity is 300 to 700 kg / m ³ .

  The production method of the vinyl chloride polymer of the present invention can be any production method as long as it undergoes the steps (I) and (II). For example, after the step (I), chlorination can be performed. Additional steps such as a step of recovering and isolating the vinyl macroinitiator (C); a step of recovering and drying the vinyl chloride polymer after the step (II) can be added. is there.

  Since the vinyl chloride polymer obtained by the present invention has a graft copolymer structure, it is excellent in moldability, such as gelling property, drawdown property, fluidity as a powder, and handling property. It becomes a polymer.

  Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited to these. The molecular weight, Mw / Mn, copolymer composition, graft composition, average particle size, bulk specific gravity, plasticizer absorption, and gelling property in Examples and Comparative Examples were measured by the following methods.

~ Measurement of molecular weight ~
Mn, Mw and Mw / Mn were determined by GPC. Tosoh Co., Ltd. (trade name) TSKgel Multipore HXL-M is used as the packed column, tetrahydrofuran is used as the mobile phase, and a differential refractometer (manufactured by Tosoh Corporation, (trade name) RI-8020) is used for peak detection. It was. Moreover, Mn, Mw, and peak top molecular weight were calculated | required in standard polystyrene conversion.

-Measurement of copolymer composition of vinyl chloride macroinitiator-
The copolymer composition of the obtained vinyl chloride macroinitiator was determined by measurement of ¹³ C-NMR (manufactured by Varian, (trade name) NMR System 400). In addition, the measurement was performed at 120 ° C. using a mixed solvent of heavy benzene / orthodichlorobenzene = 1/3 as a solvent.

  The copolymer composition was calculated according to the following formula (2) from the integrated intensity (a) of the peak at 32 ppm and the integrated intensity (b) of the peak at 54 to 58 ppm.

Copolymerization composition (mol%) = (content of allyl 2-bromoisobutyrate residue / (content of vinyl chloride residue + content of allyl 2-bromoisobutyrate residue)) = (a × 100 ) / (6 × b + a) (2)
-Measurement of polymerization composition of vinyl chloride polymer-
The polymerization composition of the obtained vinyl chloride polymer was determined by measuring ¹ H-NMR (manufactured by JEOL Ltd., (trade name) GSX270). Measurement was performed at room temperature using deuterated tetrahydrofuran as a solvent.

  In addition, the calculation of the polymerization composition when acrylic acid n-butyl ester is used as the monomer (D) is 3.9 to 4.2 ppm peak integrated intensity (c) and 4.2 to 5.0 ppm peak. Was calculated according to the following equation (3).

Polymerization composition (% by weight) = (content of acrylic acid n-butyl ester residue / (content of vinyl chloride residue + content of acrylic acid n-butyl ester residue)) = (c × 128.2 × 100) / (2 × d × 62.50 + c × 128.2) (3)
In addition, the calculation of the polymerization composition when using methyl methacrylate as the monomer (D) is calculated as the integral intensity (e) of the peak of 0.6 to 1.6 ppm and the integral of the peak of 4.2 to 5.0 ppm. It calculated according to the following formula | equation (4) from intensity | strength (f).

Polymerization composition (% by weight) = (content of methacrylic acid methyl ester residue / (content of vinyl chloride residue + content of methacrylic acid methyl ester residue)) = (e × 100.1 × 100) / ( 2 × f × 62.50 + e × 100.1) (4)
~ Measurement of average particle diameter ~
It measured based on JIS Z-8801.

~ Measurement of bulk specific gravity ~
It measured according to JIS K-6721.

~ Measurement of glass transition temperature ~
A differential scanning calorimeter (manufactured by Seiko Denshi Kogyo Co., Ltd., (trade name) EXSTAR6000) was used, and the temperature was measured at a heating rate of 10 ° C./min.

~ Evaluation of gelation ~
100 parts by weight of the obtained vinyl chloride polymer was mixed with 1 part by weight of tribasic lead sulfate, 1.3 parts by weight of lead stearate, 0.4 parts by weight of calcium stearate, and 0.1 parts by weight of stearic acid at room temperature. For 10 minutes. 60 g of this mixture was put into a plastograph tester manufactured by Brabender, and the time from when the vinyl chloride polymer was added under the conditions of a roller rotation speed of 60 rpm and a chamber temperature of 190 ° C. until the torque increased was measured. And gelation time. Moreover, the minimum value of the torque at this time was defined as the minimum torque, and the torque after gelation was defined as the steady torque.

  It was judged that the gelation property was improved as the gelation time was shorter. Moreover, it was judged that the higher the steady torque, the higher the melt viscosity.

Example 1
(Manufacture of vinyl chloride macroinitiator)
In a 3 liter stainless steel polymerization vessel equipped with a paddle type stirring blade and baffle, 1510 g (175 parts by weight) of deionized water, a saponification degree of polyvinyl alcohol having a saponification degree of 80 mol% and an average polymerization degree of 2600 (hereinafter, 1.06 g (0.12 parts by weight) of polyvinyl alcohol partially saponified was charged, and the air inside was replaced with nitrogen. Thereafter, 3.49 g (0.40 parts by weight; 0.12 mol%) of allyl-2-bromoisobutyrate, 0.352 g (0.04 parts by weight) of tert-butylperoxyneodecanoate, vinyl chloride alone 879 g (100 parts by weight) of the monomer was charged, and suspension polymerization was performed at an internal temperature of 57 ° C. while stirring. The polymerization was stopped 8 hours after the internal temperature reached 57 ° C., the unreacted monomer was recovered, the suspension slurry was filtered, and then washed with 1 liter of distilled water. Thereafter, the resultant was dried at 65 ° C. under a nitrogen stream for 6 hours, and further dried under reduced pressure at 65 ° C. for 6 hours to obtain a vinyl chloride macroinitiator in the form of particles (yield: 686 g, yield: 78%).

The obtained vinyl chloride macroinitiator had a particle size of 155 μm and a bulk specific gravity of 530 kg / m ³ . Moreover, the peak top molecular weight was 102000, Mn was 57700, and Mw / Mn was 2.45. The copolymer composition of the vinyl chloride macroinitiator determined from ¹³ C-NMR was 0.1 mol%.

(Production of vinyl chloride polymer)
Into a stainless steel polymerization vessel having an internal volume of 3 liters equipped with a paddle type stirring blade and a baffle, 0.568 g of copper (I) bromide (0.23 parts by weight; 1 molar equivalent to the starting group), 4,4′- Dionyl-2,2′-dipyridyl (4.40 g, 1.37 parts by weight; 2 molar equivalents relative to the initiator group) and 247.6 g (100 parts by weight) of the above vinyl chloride macroinitiator were charged, Nitrogen introduction was repeated three times to replace the internal air with nitrogen. Thereafter, 1360 g (500 parts by weight) of deionized water degassed in advance and 0.137 g (0.04 parts by weight) of a partially saponified polyvinyl alcohol were charged, and nitrogen substitution was performed again three times. Thereafter, 24.8 g (10 parts by weight) of acrylic acid n-butyl ester previously bubbled with nitrogen was charged, and living radical polymerization was performed at 70 ° C. while stirring. When 5 hours had elapsed, the living radical polymerization was stopped, and the suspension slurry was filtered and washed with 1 liter of distilled water. Thereafter, it was dried under reduced pressure at 30 ° C. for 6 hours to recover the monomer, and further dried under reduced pressure at 60 ° C. for 6 hours to obtain a particulate vinyl chloride polymer (yield: 269.8 g, yield). Rate: 97%).

The obtained vinyl chloride polymer had a particle size of 165 μm, a bulk specific gravity of 502 kg / m ³ , a peak top molecular weight of 103,000, Mn of 57800, and Mw / Mn of 2.80. Table 1 shows the polymerization composition, glass transition temperature, and gelation evaluation results of the obtained vinyl chloride polymer. Further, disappearance of a peak derived from the allyl-2-bromoisobutyrate residue of 31.35 ppm macroinitiator was confirmed by ¹³ C-NMR, and the progress of graft copolymerization was confirmed.

Example 2
(Production of vinyl chloride polymer)
Copper (I) bromide 0.568g (0.23 parts by weight; 1 equivalent to the starting group), 4,4'-dinonyl-2,2'-dipyridyl 4.40g (1.37 parts by weight; starting group) 27.6 moles), 247.6 g (100 parts by weight) of the vinyl chloride macroinitiator obtained in Example 1, 1360 g (500 parts by weight) deionized water, 0.137 g (0.04) of partially saponified polyvinyl alcohol. Parts by weight), instead of 24.8 g (10 parts by weight) of acrylic acid n-butyl ester, 0.360 g of copper (I) bromide (0.23 parts by weight; 1 molar equivalent to the starting group), 4,4 31.4 g of '-dinonyl-2,2'-dipyridyl (1.37 parts by weight; 2 molar equivalents relative to the initiator group), 157.0 g (100 parts by weight) of the vinyl chloride macroinitiator obtained in Example 1 , 939 g (500 parts by weight) of deionized water, Polybi Living radical polymerization was carried out in the same manner as in Example 1 except that 0.095 g (0.04 parts by weight) of saponified nyl alcohol and 31.4 g (20 parts by weight) of acrylic acid n-butyl ester were used. A vinyl chloride polymer having a shape was obtained (yield: 183.1 g, yield: 96%).

The obtained vinyl chloride polymer had a particle size of 170 μm, a bulk specific gravity of 496 kg / m ³ , a peak top molecular weight of 105000, Mn of 58700, and Mw / Mn of 2.88. In addition, Table 1 shows the polymerization composition of the obtained vinyl chloride polymer and the results of gelation evaluation.

Example 3
(Production of vinyl chloride polymer)
In a 3 liter stainless steel polymerization vessel equipped with a paddle type stirring blade and baffle, 0.566 g of copper (I) bromide (0.23 parts by weight; 1 molar equivalent to the starting group), 4,4′- It was charged with 4.39 g of dinonyl-2,2'-dipyridyl (1.37 parts by weight; 2 molar equivalents relative to the initiator group) and 246.7 g (100 parts by weight) of the vinyl chloride macroinitiator obtained in Example 1. The inside air was replaced with nitrogen by repeating vacuuming and introducing nitrogen three times. Thereafter, 1350 g (500 parts by weight) of deionized water degassed in advance and 0.137 g (0.04 parts by weight) of a partially saponified polyvinyl alcohol were charged, and nitrogen substitution was performed again three times. Thereafter, 24.7 g (10 parts by weight) of methacrylic acid methyl ester previously bubbled with nitrogen was charged, and polymerization was performed at 70 ° C. while stirring. When 5 hours had elapsed, the living radical polymerization was stopped, and the suspension slurry was filtered and washed with 1 liter of distilled water. Thereafter, it was dried under reduced pressure at 30 ° C. for 6 hours to recover unreacted monomers, and further dried under reduced pressure at 60 ° C. for 6 hours to obtain a particulate vinyl chloride polymer (yield: 268.6 g, Yield: 98%).

The obtained vinyl chloride polymer had a particle size of 160 μm, a bulk specific gravity of 508 kg / m ³ , a peak top molecular weight of 103,000, Mn of 57900, and Mw / Mn of 2.89. In addition, Table 1 shows the polymerization composition of the obtained vinyl chloride polymer and the results of gelation evaluation.

Comparative Example 1
(Production of vinyl chloride homopolymer)
A stainless steel polymerization vessel with an internal volume of 3 liters equipped with a paddle type stirring blade and a baffle was charged with 1430 g (150 parts by weight) of deionized water and 0.483 g (0.05 parts by weight) of a partially saponified polyvinyl alcohol, The internal air was replaced with nitrogen. Thereafter, 0.386 g (0.04 parts by weight) of tert-butylperoxyneodecanoate and 879 g (100 parts by weight) of vinyl chloride monomer were charged, and polymerization was carried out at 57 ° C. while stirring. When the internal pressure of the polymerization vessel decreased to 6.7 kg / cm ² , the polymerization was stopped, unreacted monomers were collected, the suspension slurry was filtered, and washed with 1 liter of distilled water. Thereafter, it was dried at 65 ° C. under a nitrogen stream for 6 hours, and further dried under reduced pressure at 65 ° C. for 6 hours to obtain a particulate vinyl chloride homopolymer (yield: 800 g, yield: 83%).

The obtained vinyl chloride homopolymer had a particle size of 160 μm, a bulk specific gravity of 504 kg / m ³ , a peak top molecular weight of 107,000, Mn of 58800, and Mw / Mn of 2.28. Table 1 shows the glass transition temperature and gelation evaluation results of the resulting vinyl chloride homopolymer.

Comparative Example 2
(Production of vinyl chloride polymer)
In a 3 liter stainless steel polymerization vessel equipped with a paddle type stirring blade and baffle, 222 g (100 parts by weight) of the vinyl chloride homopolymer obtained in Comparative Example 1, 1220 g (500 parts by weight) of deionized water, polyvinyl 0.12 g (0.05 parts by weight) of a partially saponified alcohol was charged, and the air inside was replaced with nitrogen by repeating vacuuming and introducing nitrogen three times. Thereafter, 22.2 g (10 parts by weight) of acrylic acid n-butyl ester previously bubbled with nitrogen and 0.667 g (0.3 parts by weight) of 2,2′-azobisisobutyronitrile (AIBN) were charged, Polymerization was carried out at 70 ° C. with stirring. When 5 hours had elapsed, the polymerization was stopped, and the suspended slurry was filtered and washed with 1 liter of distilled water. Then, it dried under reduced pressure at 30 ° C. for 6 hours to remove unreacted acrylic acid n-butyl ester and further dried under reduced pressure at 60 ° C. for 6 hours to obtain a vinyl chloride polymer in the form of particles (yield: 241 g). Yield: 99%).

The obtained vinyl chloride polymer had a particle size of 165 μm, a bulk specific gravity of 506 kg / m ³ , a peak top molecular weight of 107,000, Mn of 56000, and Mw / Mn of 2.70. Table 1 shows the polymerization composition, glass transition temperature, and gelation evaluation results of the obtained vinyl chloride polymer.

リビングラジカル重合によりアクリル酸ｎ−ブチルエステルを塩化ビニル系マクロ開始剤にグラフト重合した塩化ビニル系重合体（実施例１〜２）は、塩化ビニル単独重合体（比較例１）と比べてゲル化時間が短くゲル化性が向上し、加工性に優れるものである。

Vinyl chloride polymers (Examples 1 and 2) obtained by graft polymerization of acrylic acid n-butyl ester to vinyl chloride macroinitiators by living radical polymerization are more gelled than vinyl chloride homopolymer (Comparative Example 1). The gelling property is improved for a short time, and the processability is excellent.

  In addition, the vinyl chloride polymer (Comparative Example 2) obtained by carrying out normal radical polymerization of acrylic acid n-butyl ester in the presence of vinyl chloride homopolymer improved in the same manner, but the steady torque was remarkable. It has dropped to. This steady torque has a strong correlation with melt viscosity, and a decrease in steady torque indicates a decrease in melt viscosity. Therefore, in Comparative Example 2, the melt viscosity is lowered, and the substantial workability has not been improved. Further, the effect of lowering the glass transition temperature was low, and the production efficiency of the graft copolymer was inferior.

  Also in the vinyl chloride polymer (Example 3) obtained by graft polymerization of methacrylic acid methyl ester, the gelling property is improved and the processability is excellent as compared with the vinyl chloride homopolymer (Comparative Example 1).

  The vinyl chloride polymer obtained by the production method of the present invention has improved gelling properties and processability compared to conventional vinyl chloride resins, and can be used for the production of various molded products. In addition, since melt viscosity has not decreased more than necessary, the occurrence of drawdown of molten resin, deterioration of dimensional stability during extrusion molding, poor foaming during foam molding, and uniformity in thickness during blow and vacuum molding It becomes a vinyl chloride polymer excellent in moldability that prevents problems such as deterioration and generation of air marks during calendar molding, and can be expected to be developed into various molded products.

Claims (6)

A method for producing a vinyl chloride polymer, comprising the following step (I) and step (II).
Step (I): Monomer (A) and vinyl chloride monomer (B) represented by the following general formula (1) are subjected to suspension polymerization in an aqueous medium in the presence of a radical polymerization initiator and a dispersant. The process of performing and obtaining a vinyl chloride macroinitiator (C).

(1)
(In the formula, X ¹ is a chlorine atom, a bromine atom or an iodine atom, R ¹ and R ² are each independently a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms, and n is an integer of 0 to 5) .)
Step (II); at least one monomer selected from the group consisting of the vinyl chloride macroinitiator (C) obtained in Step (I) and an alkyl acrylate, alkyl methacrylate and vinyl carboxylate A step of producing a vinyl chloride polymer by performing graft copolymerization with (D) in an aqueous medium in the presence of a living radical polymerization catalyst and a dispersant. 2. The method for producing a vinyl chloride polymer according to claim 1, wherein the vinyl chloride macroinitiator (C) obtained by the step (I) has a particle shape. The monomer (D) in step (II) is at least one monomer selected from the group consisting of methyl acrylate, butyl acrylate, methyl methacrylate, butyl methacrylate, and vinyl acetate. The method for producing a vinyl chloride polymer according to claim 1 or 2. The living radical polymerization catalyst of the step (II) is composed of a metal or a metal compound of a Group 7, 8, 9, 10, or 11 element of the periodic table and a ligand compound. The method for producing a vinyl chloride polymer according to any one of claims 1 to 3. Ligand compound containing a carbon compound capable of π-bonding a copper or ruthenium, iron or nickel metal or metal compound and a nitrogen atom, oxygen atom, phosphorus atom, sulfur atom or transition metal, wherein the living radical polymerization catalyst of step (II) The method for producing a vinyl chloride polymer according to any one of claims 1 to 4, wherein: 6. The method for producing a vinyl chloride polymer according to claim 1, wherein the living radical polymerization catalyst in step (II) is composed of a copper compound and an amine compound.