JP2003012881A - Vinylchloride-based resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve flow mark, air mark, secondary processability, etc., to a level fully satisfiable at the same time in the calendering process of a vinylchloride-based resin. SOLUTION: This vinylchloride-based resin composition comprises (I) 100 pts.wt. of a vinylchloride-based resin and (II) 0.1 to 10 pts.wt. of a processability improving agent for the vinylchloride-based resin, wherein the processability improving agent for the vinylchloride-based resin is a methacrylic copolymer obtained by polymerizing monomers comprising 40 to 80 wt.% of methyl methacrylate, 20 to 60 wt.% of a methacrylate other than methyl methacrylate, and 0 to 5 wt.% of a monomer copolymerizable with the methyl methacrylate and the methacrylate, the methacrylate is expressed by CH2 =C(CH3 )COOR where the R is a 2-8C hydrocarbon group, and the copolymer being the processability improving agent has 500,000 to 1,500,000 weight-average molecular weight (Mw) obtained by the gel permeation chromatography(GPC) and 1.6 or less molecular weight distribution (Mw/Mn) expressed by the ratio of the Mw to the number-average molecular weight (Mn).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a vinyl chloride resin composition containing a vinyl chloride resin and a processability improver for the vinyl chloride resin. More specifically, it contains a specific methacrylic copolymer having a narrow molecular weight distribution as a processability improver for vinyl chloride resin, has an excellent gelation-promoting effect during molding, and has an air mark during calendar processing and The present invention relates to a vinyl chloride-based resin composition with less generation of flow marks.

[0002]

2. Description of the Related Art Vinyl chloride resins are widely used in various fields because of their excellent physical and chemical properties. However, since the softening temperature is high, the processing temperature has to be close to the thermal decomposition temperature of the resin, so that the temperature range in which molding can be processed is narrow, the time until the molten state is long, etc. Have a problem. Many techniques are known to try to overcome these drawbacks. For example, addition of a plasticizer, copolymerization of vinyl chloride with another monomer to form a vinyl chloride-based copolymer, mixing of a vinyl chloride resin with another resin-like substance, and the like.

However, all of them retain the excellent physical and chemical properties inherent to vinyl chloride resin,
Only the workability cannot be sufficiently improved. For example,
When a plasticizer is added or when vinyl chloride and another monomer are copolymerized, the physical properties of the molded product change significantly. When mixing other resin-like substances with vinyl chloride resin, most of the purpose is to lower the processing temperature by lowering the melt viscosity during molding, which apparently improves the flowability of vinyl chloride resin. Let But,
Since the kneading energy is consumed by the flow,
Although the gelation of the vinyl chloride resin is insufficient and the product is apparently transparent, its physical properties are inferior to those of the sufficiently gelled vinyl chloride resin.

On the other hand, promotion of gelation during molding of vinyl chloride resin, improvement of secondary workability, retention of gloss on the surface of the molded product during molding for a long time, smoothing of the surface of the resulting molded product. For the purpose of improving processability, there has been proposed a method of incorporating a copolymer containing methyl methacrylate as a main component as a processability improving agent. All of these are copolymers or copolymer mixtures composed of methyl methacrylate and methacrylic acid ethesul or acrylic acid ester other than methyl methacrylate. This is because when a homopolymer of methyl methacrylate is used as a processability improver, the polymer has a high softening temperature, so that it is not sufficiently dispersed under the usual processing conditions of vinyl chloride resin, resulting in an ungelled product. This is because a large amount of (fish eye) remains.

For example, Japanese Examined Patent Publication (Kokoku) No. 40-5311 discloses a methyl methacrylate-acrylic acid ester copolymer containing 25 mol% or less of acrylic acid ester. Further, JP-B-53-2898 discloses that a copolymer (i) comprising a major amount of methyl methacrylate and a small amount of an acrylate ester and / or a methacrylate ester other than methyl methacrylate, and methyl methacrylate. A two-stage polymer comprising a small amount and a copolymer (ii) consisting of an acrylic acid ester and / or a major amount of a methacrylic acid ester other than methyl methacrylate; and a copolymer (i) and a copolymer (ii). Copolymer mixtures obtained by blending in a latex state with are disclosed.

In both of the above publications, copolymerization is carried out for the purpose of reducing ungelled substances (fish eyes) when mixed with a vinyl chloride resin. The vinyl chloride resin composition containing the processability improver comprising such a specific copolymer has a high gelation rate during the molding process, resulting in an increase in the breaking elongation at high temperature of the molded product. The secondary workability of vinyl resin can be greatly improved, and not only deep drawing can be performed, but also vacuum forming and profile extrusion can be applied. Further, it also has the property of reducing air marks on the sheet during calendar processing. However, there is still a drawback that flow marks are generated on the surface of the sheet during calendar processing, which reduces the commercial value of the molded product.

On the other hand, in JP-A-4-266958, the characteristics of acrylic acid ester and methacrylic acid ester are clearly differentiated, and the amount of acrylic acid ester used is limited to 2% by weight or less. According to the patent, the advantages of the conventional processability improver are retained, and at the same time, the problem of flow marks during calendar processing is solved. But,
The effect is still insufficient.

[0008] In recent years, with the increase in size and high-speed production of calendar processing machines, the problem of flow marks generated on the surface of the calendar sheet has come to be emphasized. Therefore, there is an increasing demand for the development of a technique for obtaining sheets with high commercial value by reducing flow marks. As described above, the only drawback of the conventional processability improver is the occurrence of this flow mark, and this drawback is solved, and at the same time, the feature of the conventional processability improver containing methyl methacrylate as a main component,
In other words, the development of a processability improver that promotes gelation of vinyl chloride resin, improves the secondary processability of the molded product, and reduces the air marks on the calendar sheet is industrially developed. It is very significant.

For the purpose of solving such a flow mark problem, a copolymer containing a methacrylic acid ester other than methyl methacrylate as a main component and having a low degree of polymerization has been proposed as a processability improving agent (special feature: Kaihei 1-247409
(See the official gazette). As described above, the flow mark is significantly improved by using the processability improving agent in which the melt viscosity of the vinyl chloride resin composition is kept low. That is, it is considered that keeping the melt viscosity at the time of molding process low is effective in improving the flow mark.

However, while such a method improves the flow marks in calendering, it also sacrifices the favorable effects imparted by conventional processability improving agents such as reduction of air marks and improvement of secondary processability. To After all, the technique of keeping the melt viscosity low during molding is not an essential solution for improving all the processing characteristics. In other words, the current technology does not provide a processability improving agent that can simultaneously improve flow marks, air marks, secondary processability, etc. to a sufficiently satisfactory level in calendering vinyl chloride resin.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and its object is to provide excellent properties such as air marks and secondary processability in the calendar processing of vinyl chloride resin. It is an object of the present invention to provide a vinyl chloride resin composition containing a processability improving agent having a property of improving a flow mark while keeping it.

[0012]

SUMMARY OF THE INVENTION In order to solve the above problems, the present inventors have solved the problem of flow marks that occur during calendar processing of vinyl chloride resin by providing excellent characteristics such as air marks and secondary processability. We conducted a study to solve the problem while maintaining the above. As a result, a copolymer obtained by polymerizing a specific range amount of methyl methacrylate and a monomer containing a low-molecular-weight methacrylic acid ester other than methyl methacrylate, which has a specific range of molecular weight and a narrow molecular weight distribution. It has been found that the copolymer having the compound is added to a vinyl chloride resin as a processability improver. Such a vinyl chloride-based resin composition has the same gelation acceleration, improved secondary workability, and improved workability as air marks are reduced, and at the same time, the flow marks in calendar processing are greatly improved. It was found that the present invention has been completed.

The vinyl chloride resin composition of the present invention provides a vinyl chloride resin composition containing the following two components: (I) 100 parts by weight of vinyl chloride resin; and (II)
0.1-10 parts by weight of processability improver for vinyl chloride resin,
Here, the processability improver is methyl methacrylate 40-
Polymerization of 80% by weight, 20 to 60% by weight of a methacrylic acid ester other than methyl methacrylate, and 0 to 5% by weight of a monomer copolymerizable with the methyl methacrylate and the methacrylic acid ester is performed. The methacrylic acid ester is represented by CH ₂ ═C (CH ₃ ) COOR,
Is a hydrocarbon group having 2 to 8 carbon atoms; and the copolymer has a weight average molecular weight (Mw) of 500,000 to 1,500,000 determined by gel permeation chromatography (GPC) measurement, and The molecular weight distribution (Mw / Mn) represented by the ratio with the average molecular weight (Mn) is 1.6 or less.

In a preferred embodiment, the processability improver comprises a plurality of the above copolymers.

In a preferred embodiment, the weight average molecular weights (Mw) of the plural kinds of copolymers are different by 10,000 or more.

In a preferred embodiment, the copolymer has a molecular weight distribution (Mw / Mn) of 1.4 or less.

In a preferred embodiment, the copolymer has a weight average molecular weight (Mw) of 600,000 to 1,000,000.

In a preferred embodiment, the processability improver contains a copolymer having at least one thiocarbonylthio structure in one molecule in an amount of 50% or more based on the total copolymer. It

In a preferred embodiment, the copolymer having at least one thiocarbonylthio structure in one molecule is contained in a proportion of 70% or more based on the total copolymer.

The present invention also relates to methyl methacrylate 40-
Polymerization of 80% by weight, 20 to 60% by weight of a methacrylic acid ester other than methyl methacrylate, and 0 to 5% by weight of a monomer copolymerizable with the methyl methacrylate and the methacrylic acid ester is performed. A processability improver for a vinyl chloride resin, comprising a methacrylic copolymer obtained by the method, wherein the methacrylic acid ester is C
H ₂ ═C (CH ₃ ) COOR, wherein R is 2
To 8 hydrocarbon groups, and the copolymer has a weight average molecular weight (Mw) of 500,000 to 1,500,000 determined by gel permeation chromatography (GPC) and a number average molecular weight (Mn). Molecular weight distribution (M
Provided is a processability improving agent for vinyl chloride-based resins having a w / Mn) of 1.6 or less.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The vinyl chloride resin composition of the present invention contains a vinyl chloride resin and a processability improving agent for vinyl chloride resin. This vinyl chloride resin processability improver is
It is a methacrylic copolymer obtained by polymerizing a specific range of methyl methacrylate and a low-molecular-weight methacrylic acid ester other than methyl methacrylate, and a monomer copolymerizable with them, if necessary. The vinyl chloride resin and the processability improving agent for vinyl chloride resin contained in the composition of the present invention will be sequentially described below.

[Vinyl Chloride Resin] The vinyl chloride resin used in the present invention is not particularly limited, and any vinyl chloride resin commonly used can be used. As the vinyl chloride resin, for example, polyvinyl chloride, preferably 80% or more of vinyl chloride and a monomer copolymerizable with the vinyl chloride (for example, vinyl acetate, propylene, styrene, acrylic acid ester, etc.) Examples thereof include copolymers and post-chlorinated polyvinyl chloride. These may be used alone or in combination of two or more.

[Component of Methacrylic Copolymer Used as Processability Improver] The methacrylic copolymer used as a processability improver for vinyl chloride resin contained in the vinyl chloride resin composition of the present invention is , 40 to 80% by weight of methyl methacrylate, 20 to 60% by weight of a methacrylic acid ester other than methyl methacrylate, and 0 to 5% by weight of a monomer copolymerizable with the methyl methacrylate and the methacrylic acid ester. It is a methacrylic copolymer obtained by polymerizing a monomer. Preferably, the content of methyl methacrylate is 50 to 70% by weight. Hereinafter, in the present specification, the methacrylic acid ester other than the methyl methacrylate may be referred to as a low molecular weight methacrylic acid ester.

The low molecular weight methacrylic acid ester is C
H ₂ ═C (CH ₃ ) COOR, wherein R is 2
~ 8 hydrocarbon groups (alkyl groups, aralkyl groups, alicyclic groups, etc.). Preferred compounds include ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate and the like. These may be used alone or in combination of two or more. In particular, n-butyl methacrylate is preferable because it is highly effective in improving both flow marks and air marks to a satisfactory level.

The content of the low molecular weight methacrylic acid ester in the methacrylic copolymer is 20 to 60% by weight, preferably 30 to 50% by weight, based on the total monomer components.
Is. By using a copolymer containing methyl methacrylate and a low molecular weight methacrylic acid ester, it becomes possible to prevent the generation of an ungelled product. When the amount of the low molecular weight methacrylic acid ester is less than 20% by weight, the amount of ungelled product increases when the obtained methacrylic copolymer and the vinyl chloride resin are kneaded. On the other hand, when the content of the low molecular weight methacrylic acid ester exceeds 60% by weight (see, for example, Japanese Patent Publication No. 1-247409), the methacrylic copolymer obtained is kneaded with a vinyl chloride resin. The secondary processability and the transparency of the resulting molded article are reduced. When acrylic acid ester is used instead of low molecular weight methacrylic acid ester, an ungelled product is not generated and kneading can be sufficiently performed, but the problem of flow mark cannot be solved.

In the production of the methacrylic copolymer, a monomer copolymerizable with methyl methacrylate and a low molecular weight methacrylic acid ester may be used, if necessary. Hereinafter, in this specification, it may be simply referred to as a copolymerizable monomer. Examples of such copolymerizable monomers include acrylic acid esters (methyl acrylate,
Examples thereof include ethyl acrylate, n-butyl acrylate, etc., unsaturated nitriles (acrylonitrile, methacrylonitrile, etc.), vinyl esters (vinyl acetate, vinyl propionate, etc.) and the like. These may be used alone or in combination of two or more. The content of the copolymerizable monomer is preferably 5% by weight or less based on the whole monomer components so as not to impair the flow mark improving effect.

The processability improving agent having a narrow molecular weight distribution of the present invention can be synthesized by a generally known living polymerization. For example, a radical polymerization method carried out in the presence of a compound having a thiocarbonylthio structure can be mentioned as the production method. Regarding such radical polymerization, International Patent WO98 / 01478, International Patent WO99 / 0509
9, International Patent WO99 / 31144, Macromol
ecules 1998 Vol. 31, No. 16, 5559-556
2 pages, Macromolecules 1999 3
Volume 2, No. 6, pages 2071 to 2074, Polym. Pr
epr. Vol. 40, No. 2, pp. 342-343, 1999,
Polym. Prepr. 1999 Volume 40 No. 2 397
~ 398, Polym. Prepr. 1999, 40, No. 2, 899-900, Polym. Pre
pr. 1999 Volume 40 No. 2, pages 1080-1108, Macromolecules 1999 Volume 32 2
No. 1, pages 6977-6980, Macromolec
ules 2000, Vol. 33, No. 2, pp. 243-245,
Macromol. Symp. 2000 Volume 150 33
~ Page 38 and the like.

[Compound Having Thiocarbonylthio Structure] As the compound having a thiocarbonylthio structure, which is preferably used for the production of the methacrylic copolymer, the compounds described in the above literature can be used. (1)

[0029]

[Chemical 1]

(In the formula, R ¹ is a p-valent organic group having 1 or more carbon atoms, and the p-valent organic group includes a nitrogen atom, an oxygen atom, a sulfur atom, a halogen atom, a silicon atom, a phosphorus atom, and It may contain at least one of the metal atoms and may be a high molecular weight compound; Z ¹ is a hydrogen atom, a halogen atom, or a monovalent organic group having 1 or more carbon atoms,
The monovalent organic group may contain at least one of a nitrogen atom, an oxygen atom, a sulfur atom, a halogen atom, a silicon atom, and a phosphorus atom, and may be a high molecular weight compound; Z ¹ is When a plurality of them are present, they may be the same or different from each other; p is an integer of 1 or more) (hereinafter, "compound (1) having a thiocarbonyl structure"), or simply " Compound (1) ") and general formula (2)

[0031]

[Chemical 2]

(In the formula, R ² is a monovalent organic group having 1 or more carbon atoms, and the monovalent organic group includes a nitrogen atom, an oxygen atom, a sulfur atom, a halogen atom, a silicon atom, a phosphorus atom, and It may contain at least one of the metal atoms and may be a high molecular weight compound; Z ² is an oxygen atom (q =
2), sulfur atom (when q = 2), nitrogen atom (q
= 3) or a q-valent organic group having 1 or more carbon atoms, and the q-valent organic group is at least a nitrogen atom, an oxygen atom, a sulfur atom, a halogen atom, a silicon atom, and a phosphorus atom. It may contain one, may be a high molecular weight compound; a plurality of R ² may be the same or different from each other; q is a compound represented by the following (hereinafter, "Compound (2) having a thiocarbonyl structure", or simply "compound (2)" may be mentioned).

R ¹ of the compound (1) having the thiocarbonylthio structure is not particularly limited. From the viewpoint of availability of the compound, preferably, R ¹ has 1 to 20 carbon atoms,
And p is 6 or less. Examples of R ¹ include an alkyl group, a substituted alkyl group, an aralkyl group, a substituted aralkyl group, a divalent or higher aliphatic hydrocarbon group, a divalent or higher aromatic hydrocarbon group, and a divalent or higher aliphatic compound having an aromatic ring. Group hydrocarbon group, divalent or more aromatic hydrocarbon group having an aliphatic group, divalent or more aliphatic hydrocarbon group containing a hetero atom, divalent or more aromatic substituted hydrocarbon group containing a hetero atom, etc. is there.
The following groups are preferable in terms of availability of the compound: benzyl group, 1-phenylethyl group, 2-phenyl-2-propyl group, 1-acetoxyethyl group, 1- (4-methoxyphenyl) ethyl group, ethoxy. Carbonylmethyl group, 2-
Ethoxycarbonyl-2-propyl group, 2-cyano-2
-Propyl group, t-butyl group, 1,1,3,3-tetramethylbutyl group, 2- (4-chlorophenyl) -2-propyl group, vinylbenzyl group, t-butylsulfide group, 2-carboxylethyl group A carboxylmethyl group, a cyanomethyl group, a 1-cyanoethyl group, a 2-cyano-2-butyl group, and an organic group represented by the following formula:

[0034]

[Chemical 3]

(In the formula, r represents an integer of 0 or more, and s is 1
Indicates the above integer). In the above formula, r and s are preferably 500 or less in view of availability of the compound.

Further, as described above, R ¹ may be a high molecular weight compound, examples of which include the following groups: a hydrocarbon group having a polyethylene oxide structure and a hydrocarbon having a polypropylene oxide structure. Group, a hydrocarbon group having a polytetramethylene oxide structure, a hydrocarbon group having a polyethylene terephthalate structure, a hydrocarbon group having a polybutylene terephthalate structure, a hydrocarbon group having a polydimethylsiloxane structure, a hydrocarbon group having a polycarbonate structure, A hydrocarbon group having a polyethylene structure, a hydrocarbon group having a polypropylene structure, a hydrocarbon group having a polyacrylonitrile structure, and the like. These hydrocarbon groups may contain at least one of oxygen atom, nitrogen atom, and sulfur atom, and may contain cyano group, alkoxy group and the like. Their molecular weight is usually 500 or more. Hereinafter, in the present invention, the high molecular weight group refers to the above group.

Z ¹ of the compound (1) is not particularly limited. In view of availability of the compound, when Z ¹ is an organic group, the carbon number thereof is preferably 1 to 20. Z ¹ includes the following groups: an alkyl group, a substituted alkyl group, an alkoxy group, an aryloxy group, an aryl group,
Substituted aryl group, aralkyl group, substituted aralkyl group, N
-Aryl-N-alkylamino group, N, N-diarylamino group, N, N-dialkylamino group, thioalkyl group, dialkylphosphinyl group and the like. From the viewpoint of availability of the compound, the following groups are preferable: phenyl group, methyl group, ethyl group, benzyl group, 4-chlorophenyl group, 1-naphthyl group, 2-naphthyl group, diethoxyphosphinyl group,
n-butyl group, t-butyl group, methoxy group, ethoxy group, thiomethyl group (methyl sulfide), phenoxy group, thiophenyl group (phenyl sulfide), N, N-
Dimethylamino group, N, N-diethylamino group, N-phenyl-N-methylamino group, N-phenyl-N-ethylamino group, thiobenzyl group (benzyl sulfide),
A pentafluorophenoxy group, and the following formula:

[0038]

[Chemical 4]

An organic group represented by:

Further, R ² of the compound (2) having the thiocarbonylthio structure is not particularly limited. From the viewpoint of availability of the compound, the carbon number of R ² is preferably 1 to 20. Examples of R ² include an alkyl group, a substituted alkyl group, an aralkyl group, and a substituted aralkyl group. As examples thereof, the following groups are preferable in terms of availability of the compound: benzyl group, 1-phenylethyl group, 2-phenyl-2-propyl group, 1-acetoxyethyl group, 1- (4
-Methoxyphenyl) ethyl group, ethoxycarbonylmethyl group, 2-ethoxycarbonyl-2-propyl group, 2
-Cyano-2-propyl group, t-butyl group, 1,1,
3,3-tetramethylbutyl group, 2- (4-chlorophenyl) -2-propyl group, vinylbenzyl group, t-butylsulfide group, 2-carboxyethyl group, carboxymethyl group, cyanomethyl group, 1-cyanoethyl group,
2-cyano-2-butyl group, and an organic group represented by the following formula:

[0041]

[Chemical 5]

(In the formula, r represents an integer of 0 or more, and s is 1
Indicates the above integer). In the above formula, r and s are preferably 500 or less in view of availability of the compound.

Z ² of the compound (2) is not particularly limited. In view of availability of the compound, when Z ² is an organic group, the carbon number thereof is preferably 1 to 20. q is preferably 6 or less. Examples of Z ² include a divalent or higher aliphatic hydrocarbon group, a divalent or higher aromatic hydrocarbon group, a divalent or higher aliphatic hydrocarbon group having an aromatic ring, and a divalent or higher aliphatic group. Aromatic hydrocarbon group, containing hetero atom 2
Examples thereof include a valent or higher valent aliphatic hydrocarbon group and a divalent or higher valent aromatic substituted hydrocarbon group containing a hetero atom. In terms of compound availability, the following formula:

[0044]

[Chemical 6]

Organic groups represented by are preferred.

As the above-mentioned compound having a thiocarbonylthio structure, a polymer having a thiocarbonylthio structure at both terminals can be easily produced, and therefore, the compound having a thiocarbonylthio structure represented by the general formula (3) is provided at both terminals. Compounds having are preferred:

[0047]

[Chemical 7]

(In the formula, R ³ is a divalent organic group having 1 or more carbon atoms, and the divalent organic group includes a nitrogen atom, an oxygen atom, a sulfur atom, a halogen atom, a silicon atom, a phosphorus atom, and It may contain at least one of metal atoms and may be a high molecular weight compound; Z ³ is a hydrogen atom, a halogen atom, or a monovalent organic group having 1 or more carbon atoms,
The monovalent organic group may contain at least one of a nitrogen atom, an oxygen atom, a sulfur atom, a halogen atom, a silicon atom, and a phosphorus atom, and may be a high molecular weight compound; Z ³ may be the same or different from each other).

R ³ of the compound having a thiocarbonylthio structure at both ends is not particularly limited, but R ³ preferably has 1 to 20 carbon atoms in view of availability of the compound. In terms of availability, the following formula:

[0050]

[Chemical 8]

The structure represented by is preferred.

Z ³ of the compound having the above thiocarbonylthio structure at both ends is not particularly limited. In view of availability of the compound, when Z ³ is an organic group, the carbon number thereof is
It is preferably 1 to 20. Z ³ includes the following groups: an alkyl group, a substituted alkyl group, an alkoxy group, an aryloxy group, an aryl group, a substituted aryl group,
Aralkyl group, substituted aralkyl group, N-aryl-N-
Alkylamino group, N, N-diarylamino group, N,
N-dialkylamino group, thioalkyl group, dialkylphosphinyl group and the like. From the viewpoint of availability of the compound, the following groups are preferable: phenyl group, methyl group, ethyl group, benzyl group, 4-chlorophenyl group, 1-naphthyl group, 2-naphthyl group, diethoxyphosphinyl group, n-. Butyl group, t
-Butyl group, methoxy group, ethoxy group, thiomethyl group (methyl sulfide), phenoxy group, thiophenyl group (phenyl sulfide), N, N-dimethylamino group,
N, N-diethylamino group, N-phenyl-N-methylamino group, N-phenyl-N-ethylamino group, thiobenzyl group (benzyl sulfide), pentafluorophenoxy group, and organic group represented by the following formula:

[0053]

[Chemical 9]

(In the formula, r represents an integer of 0 or more, and s is 1
Indicates the above integer). In the above formula, r and s are preferably 500 or less in view of availability of the compound.

Specific examples of the compound having the above thiocarbonylthio structure include, but are not limited to, the compounds represented by the following formulas:

[0056]

[Chemical 10]

(In the formula, Me represents a methyl group, Et represents an ethyl group, Ph represents a phenyl group, and Ac represents an acetyl group).

Among the compounds having a thiocarbonylthio structure, it is preferable to use a compound having a chain transfer constant of 0.1 or more under the applicable polymerization conditions, in that the molecular weight and the molecular weight distribution of the resulting polymer can be precisely controlled. Is preferred. The chain transfer constant is described in the above document. As the compound having a thiocarbonylthio structure used in the present invention, a polymer having a smaller molecular weight distribution is obtained,
In terms of improving both the air mark and the flow mark to a satisfactory level, the chain transfer constant is preferably 1 or more, more preferably 10 or more.

The amount of the compound having a thiocarbonylthio structure used in the polymerization reaction is not particularly limited. It is possible to control the degree of polymerization and the number average molecular weight of the polymer by adjusting the molar ratio of this compound to the monomer. For example, when synthesizing a polymer having a degree of polymerization of 1000, a compound having a thiocarbonylthio structure is added at a ratio of 1 mol of thiocarbonylthio group to 1000 mol of a monomer.

[Outline of Preparation of Methacrylic Copolymer Used as Processability Improver] In the present invention, for example, in the presence of the compound having the above thiocarbonylthio structure, methyl methacrylate and the above low molecular weight methacrylic acid are used. By radical polymerization of a monomer containing an ester as a main component, a methacrylic copolymer having a thiocarbonylthio structure introduced can be obtained. Here, the monomer containing methyl methacrylate and a low-molecular-weight methacrylate ester as a main component means 40 to 80% by weight of methyl methacrylate and a methacrylate ester 2 other than methyl methacrylate.
A monomer containing 0 to 60% by weight, and if necessary, a monomer copolymerizable with methacrylic acid ester is preferably contained in an amount of 5% by weight or less.

In the polymerization reaction using the above-mentioned monomer whose main component is methyl methacrylate and low-molecular-weight methacrylic acid ester, a compound having a thiocarbonylthio structure is used as a chain transfer agent, and reversible addition elimination chain transfer (RAFT) is used. Polymerization occurs to form a methacrylic copolymer. For example, as shown in the scheme below, when a compound (1) having a thiocarbonylthio structure is reacted with methyl methacrylate (X) and a low molecular weight methacrylic acid ester (Y), a methacrylic copolymer (4) is obtained. Is formed. When the compound (2) having a thiocarbonylthio structure is used, a methacrylic copolymer (5) is formed.

[0062]

[Chemical 11]

In the above scheme, n ₁ and n ₂ represent the number of bonded monomers. Z ¹ , R ¹ , p, Z ² , R
² and q are as defined in the section of the compound having a thiocarbonylthio structure described above. (Xn ₁ / Yn
₂ ) indicates that methyl methacrylate (X) and low molecular weight methacrylic acid ester (Y) are contained as copolymerization components. N ₁ and n ₂ change depending on the charged amounts of X and Y and the reaction conditions. These may be copolymers in the form of random copolymers, block copolymers and the like. When p or q is 3 or more, a branched methacrylic copolymer is formed.

[Solvent and Additive Used for Polymerization] A type of radical polymerization using the above-mentioned monomer having methyl methacrylate and a low molecular weight methacrylic acid ester as a main component in the presence of the above-mentioned compound having a thiocarbonylthio structure. Is not particularly limited. Solution polymerization, emulsion polymerization,
It is possible to apply methods commonly used in the art such as suspension polymerization and bulk polymerization. A compound having a thiocarbonylthio structure may be present in these polymerization reaction systems.

In carrying out the radical polymerization, a polymerization additive usually used in the art is used, if necessary. Examples of additives used include dispersion emulsifiers, suspension stabilizers, polymerization initiators, pH adjusters, antioxidants, polymerization degree adjusters, chain transfer agents, gelation improvers, antistatic agents, emulsifiers, stabilizers. , A scale inhibitor, etc. can be used. The type, usage method, and usage amount of these compounds can also be appropriately determined according to the method usually used in the art.

Among the above-mentioned polymerization additives, the dispersion emulsifier improves the dispersion stability of the methacrylic monomer in the aqueous emulsion or suspension in the case of emulsion polymerization, suspension polymerization or fine suspension polymerization. And is added for the purpose of efficient polymerization. Examples of the dispersion emulsifier include the following emulsifiers,
Non-limiting examples: Anionic surfactants such as fatty acid salts, alkyl sulfate ester salts, alkylbenzene sulfonate salts (eg sodium dodecylbenzenesulfonate), alkyl phosphate ester salts, sulfosuccinate diester salts; polyoxyethylene alkyl ethers. ,
Nonionic surfactants such as polyoxyethylene fatty acid esters and glycerin fatty acid esters; cationic surfactants such as alkylamine salts. These emulsifiers may be used alone or in combination of two or more.

The polymerization initiator used in the above polymerization reaction is not particularly limited, and a polymerization initiator usually used in the art can be used. For example, a water-soluble or oil-soluble polymerization initiator, a redox type polymerization initiator and the like can be used. For example, a usual inorganic initiator such as persulfate, an organic peroxide, an azo compound or the like is used alone, or with the above compound, sulfite, hydrogen sulfite, thiosulfate, a first metal salt (for example, sulfuric acid It can also be used as a redox polymerization initiator in combination with ferrous iron), sodium formaldehyde sulfoxylate and the like. As the polymerization initiator, persulfates such as sodium persulfate, potassium persulfate and ammonium persulfate are preferable. Organic peroxides such as t-butyl hydroperoxide, cumene hydroperoxide, benzoyl peroxide and lauroyl peroxide are preferable because both flow marks and air marks can be improved.

[Preparation of Methacrylic Copolymer] The methacrylic copolymer used as the processability improver comprises 40 to 80% by weight of methyl methacrylate and 20 to 60% by weight of the low molecular weight methacrylic acid ester. If necessary, it is obtained by polymerizing a monomer composed of 0 to 5% by weight of the other copolymerizable monomer. Preferably,
Polymerization is performed using the compound having the thiocarbonylthio structure. The embodiment of polymerization is also not particularly limited, and batch methods, continuous methods, sequential addition methods, and other methods commonly used in the art can be widely applied.

For example, when a polymerization method using a compound having a thiocarbonylthio structure is adopted, there is no particular limitation on the timing of addition of the compound having a thiocarbonylthio structure to the polymerization reaction system. For example, it may be charged into the reaction vessel before the initiation of the polymerization, may be introduced into the reaction vessel at the same time as the initiation of the polymerization, or may be introduced into the reaction vessel during the polymerization reaction. Of the various addition methods, in terms of obtaining a polymer having a small molecular weight distribution, a method of charging the reaction vessel before the start of polymerization and a method of introducing the reaction vessel into the reaction vessel at the start of the polymerization are preferable. It is more preferable to use the method described above. The polymerization initiator can be charged at any timing in the charging step.

Thus, the methacrylic copolymer having the thiocarbonylthio structure introduced therein is obtained by radically polymerizing the monomer in the presence of the compound having the thiocarbonylthio structure.

Gel permeation chromatography (GP) of the methacrylic copolymer used as the processability improver.
C) The weight average molecular weight (Mw) determined by measurement is 500,000 to 1,500,000, and the molecular weight distribution represented by the ratio (Mw / Mn) to the number average molecular weight (Mn) is 1.6 or less. Methyl methacrylate 50-
70% by weight and low molecular weight methacrylic acid ester 30-
A copolymer obtained by polymerizing 50% by weight of a monomer, having a weight average molecular weight of 600,000 to 1,000,000 and a molecular weight distribution of 1.4 or less is preferable. As the processability improver, plural kinds of copolymers having different molecular weights, particularly copolymers having different Mw of 10,000 or more may be mixed and used. Since each copolymer has a narrow molecular weight distribution, for example, when a copolymer having a Mw of about 500,000 to 700,000 and a copolymer having a Mw of about 1.2 million to 1,500,000 are combined, the low molecular weight component has a flow mark improving effect. And a component on the high molecular weight side bring about an air mark improving effect, and a resin composition having a good balance can be obtained.

The weight average molecular weight (Mw) of the methacrylic copolymer used as the above-mentioned processability improver is 500,000 to 1,500,000, since it is possible to improve the air mark and the flow mark at the same level at the same time, preferably It is 600,000 to 1,000,000. Weight average molecular weight (Mw) is 50
If it is less than 10,000, the flow marks are good, but many air marks are generated, and the kneading ability as a processability improver and the secondary processability of the molded product are deteriorated. Even if the amount added to the vinyl chloride resin is increased in order to improve this drawback, the flow mark is only deteriorated, and improvement of the air mark can hardly be expected. On the other hand, when the weight average molecular weight (Mw) exceeds 1.5 million, many flow marks are generated. If the addition amount to the vinyl chloride resin is reduced to solve this drawback, the air mark deteriorates, and it is impossible to improve both the flow mark and the air mark to a satisfactory level.

Among the methacrylic copolymers, a copolymer having a thiocarbonylthio structure, particularly when mixed with various additives to be described later, combines a vinyl chloride resin with additives such as stabilizers and lubricants. Compatibility is improved, and transparency is also improved (improved transmittance and reduced scattering). Therefore, from the viewpoint of improving the physical properties of the vinyl chloride resin composition of the present invention, the copolymer preferably has at least 50% of polymer molecules having at least one thiocarbonylthio structure in one molecule, It is more preferable that 70% or more of the molecular chains having at least one thiocarbonylthio structure be present in one molecule. The ratio here is based on the number of polymer molecules (the number of moles).

From the above viewpoints, the processability improving agent of the present invention is preferably one having a plurality of thiocarbonyl structures in one molecule, and a methacrylic copolymer having a thiocarbonylthio structure at both ends is preferable. More preferable.

[Vinyl Chloride Resin Composition] The vinyl chloride resin composition of the present invention contains a vinyl chloride resin, the above-mentioned processability improving agent for vinyl chloride resin, and, if necessary, various additives.

In the composition of the present invention, the content of the processability improver is 0.1% based on 100 parts by weight of the vinyl chloride resin.
The amount is 1 to 10 parts by weight, preferably 0.2 to 5 parts by weight, and more preferably 0.
5 to 3 parts by weight. When the amount of the processability improver added is less than 0.1 part by weight, problems may occur in the air mark and the secondary processability of the molded product. If it exceeds 10 parts by weight, the improvement of the air mark is recognized, but the problem of the flow mark may occur.

Examples of additives contained in the composition of the present invention include stabilizers, lubricants, impact resistance enhancers, plasticizers, colorants, fillers and foaming agents.

The composition of the present invention is excellent in molding processability and secondary processability and retains the physical and chemical properties inherent in vinyl chloride resins, and all vinyl chloride resins can be used. It is preferably used in the field. In particular,
When used to manufacture molded products by calendering, while maintaining excellent properties such as air marks and secondary processability,
It is possible to significantly reduce the occurrence of flow marks.

To explain the present invention more specifically,
Examples and comparative examples are shown below, but the present invention is not limited to these examples.

[0080]

EXAMPLES In the following examples, "parts" means "parts by weight" and "%" means "% by weight" unless otherwise specified. In the examples, ion-exchanged water was used for all water.

The evaluation methods of the physical properties used in the following examples and comparative examples are summarized below.

(1) The number average molecular weight, weight average molecular weight and molecular weight distribution were measured by the following GPC analyzer and method. System: Waters GPC system (product name 510), Column: Showa Denko KK Sh
odex K-802.5 and K-804 (polystyrene gel), mobile phase: chloroform. The number average molecular weight and the like were calculated in terms of polystyrene.

(2) Thiocarbonyl To identify the thio structure, NMR (Gemini-300) manufactured by VARIAN was used, and a sample solution using CDCl ₃ (deuterated chloroform) as a deuterated solvent was prepared and measured.

(3) The content of the polymer having a thiocarbonylthio structure was calculated by the following method. First, elemental analysis of total sulfur content in a sample (using oxygen flask combustion method;
Measured by ion chromatography using hydrogen peroxide as an absorbing liquid; DX-500 GP manufactured by Dionex
40, ED40). Next, the thiocarbonylthio structure content was calculated from the obtained sulfur concentration based on the molecular weight of each sample obtained by GPC.

(4) Polyvinyl chloride (Kanevinyl S10, manufactured by Kanegafuchi Chemical Industry Co., Ltd.) was used in the following various workability tests.
07) 100 parts, polymer sample (workability improver) 3.0
Parts, octyltin mercaptide-based stabilizer (TVS # 8831 manufactured by Nitto Kasei Co., Ltd.) 1.5 parts, epoxidized soybean oil 1.5 parts, butyl stearate 1 part, and fatty acid polyglycol ester 0 The vinyl chloride resin composition obtained by blending 0.5 part was used.

(4-1) Regarding the flow mark, each component of the composition was blended using an 8-inch roll at 200 ° C. and a rotation speed of 20 rpm, and kneaded for 3 minutes,
A sheet having a thickness of 0.5 mm, a length of 800 mm and a width of 500 mm was produced, and the flow mark amount on the sheet was visually judged.

(4-2) The air mark has a thickness of 2 mm and a length of 800 mm under the same processing conditions as the flow mark.
A sheet having a width of 500 mm was produced, and the size and number of air marks on the sheet were visually determined.

The flow mark and air mark are
In each case, the evaluation was performed in the order of goodness: 4 grades of ⊚, ○, Δ, and ×. Here, ◎ indicates that there are almost no flow marks or air marks, ○ indicates that there are very few flow marks or air marks, and △ indicates that the flow marks or air marks are conspicuous and may be a practical problem.
And, x is a flow mark or air mark that is very noticeable.

(4-3) About the ungelled material, the thickness is 0.3 mm and the length is 800 under the processing conditions similar to those of the flow mark.
A sheet having a size of 500 mm and a width of 500 mm was prepared, and the number of ungelled substances (fish eyes) on the sheet was visually judged, and evaluated in good order in four grades of ⊚, ◯, Δ, and ×.
Here, ◎ indicates that there is no ungelled substance, ○ indicates that there is almost no ungelled substance, Δ indicates that there is scattered ungelled substance, which is considered to be a practical problem, and × indicates that many ungelled substances stand out. It is a thing.

(4-4) Regarding transparency, kneading was performed for 5 minutes at 170 ° C. using an 8-inch roll, and the thickness was about 2 mm.
Got a sheet of. Three sheets were laminated and pressed at 180 ° C. for 15 minutes to obtain a sheet having a thickness of 5 mm. Cut this sheet into 40 mm x 60 mm,
Nippon Denshoku Industries Co., Ltd. Sigma 80COLOR MEAS
Total light transmittance (%) by URING SYSTEM
And the scattered light (%) was measured.

(4-5) As a measure of secondary workability, 10
The tensile elongation at break at 0 ° C was evaluated. 8 test pieces
After kneading for 5 minutes at 100 ° C using an inch roll, 18
Using a JIS No. 2 dumbbell produced by pressing at 0 ° C for 15 minutes, at 100 ° C, a speed of 200 mm /
A tensile test was performed in minutes to measure the breaking elongation.

Example 1 A reactor equipped with a stirrer was charged with 2 parts of sodium dodecylbenzenesulfonate as a dispersion emulsifier and 0.1 part of potassium persulfate as a polymerization initiator, which had been previously dissolved in water, and water was further added. Total 20
It was set to 0. After replacing the inside of the reactor with nitrogen to remove oxygen in the space and water, the content was heated to 60 ° C. with stirring. To this content, 5 parts of a monomer mixture consisting of 60 parts of methyl methacrylate and 40 parts of n-butyl methacrylate and 0.01 part of 2- (2-phenylpropyl) dithiobenzoate, which is a compound having a thiocarbonylthio structure, were added. Gradually added over time. Even after the addition of the monomer mixture, the contents are kept stirring at 60 ° C and stirred for 2
I continued for 4 hours. After the polymerization was completed, it was cooled to obtain a polymer latex. This latex is salted out and coagulated with salt,
It was filtered, washed with water and dried to obtain a powdery polymer sample. The weight average molecular weight (M
w) was 850,000. The presence of a thiocarbonylthio group was also confirmed by NMR analysis. From the content of sulfur atoms by elemental analysis, the content of the polymer having a thiocarbonylthio group was 61%. Using the obtained polymer sample, workability evaluation for generation of flow marks, air marks, etc. was performed as described in (4) above. The results are shown in Table 1.

(Example 2) A polymer sample was obtained in the same manner as in Example 1 except that 45 parts of methyl methacrylate and 55 parts of ethyl methacrylate were used as the monomers. The weight average molecular weight determined by GPC measurement of this polymer sample was 73.
It was good. The presence of a thiocarbonylthio group was also confirmed by NMR analysis. The content of the polymer having a thiocarbonylthio group was 76%. Similar workability evaluation was performed using the obtained polymer sample. The results are shown in Table 1.

Example 3 As a monomer, 60 parts of methyl methacrylate and 2-ethylhexyl methacrylate 4 were used.
A polymer sample was obtained in the same manner as in Example 1 except that 0 part was used. The weight average molecular weight of this polymer sample determined by GPC was 700,000. The presence of a thiocarbonylthio group was also confirmed by NMR analysis. The content of the polymer having a thiocarbonylthio group was 98%. Similar workability evaluation was performed using the obtained polymer sample. The results are shown in Table 1.
Shown in.

Example 4 A polymer sample was prepared in the same manner as in Example 1 except that 60 parts of methyl methacrylate, 38 parts of n-butyl methacrylate and 2 parts of n-butyl acrylate were used as the monomers. Got The weight average molecular weight of this polymer sample measured by GPC was 750,000. NMR
The analysis also confirmed the presence of the thiocarbonylthio group. The content of the polymer having a thiocarbonylthio group was 70%. Similar workability evaluation was performed using the obtained polymer sample. The results are shown in Table 1.

Example 5 A polymer sample was prepared in the same manner as in Example 1 except that 60 parts of methyl methacrylate, 35 parts of n-butyl methacrylate and 5 parts of n-butyl acrylate were used as the monomers. Got The weight average molecular weight of this polymer sample measured by GPC was 720,000. NMR
The analysis also confirmed the presence of the thiocarbonylthio group. The content of polymer molecules having a thiocarbonylthio group is 78.
%Met. Similar workability evaluation was performed using the obtained polymer sample. The results are shown in Table 1.

Example 6 A polymer sample was obtained in the same manner as in Example 1 except that the addition of the monomer was changed as follows. First, 50 parts of methyl methacrylate and 2- (2
-Phenylpropyl) dithiobenzoate (0.01 parts) was gradually added over 2.5 hours to prepare a polymer latex, and after 10 hours, 25 parts of methyl methacrylate was further added.
And 25 parts of n-butyl methacrylate were added over 2.5 hours. In this way
A two-stage copolymer latex was obtained. The weight average molecular weight of this latex powder determined by GPC was 790,000. The presence of a thiocarbonylthio group was also confirmed by NMR analysis. The content of the polymer having a thiocarbonylthio group was 69%. Similar workability evaluation was performed using the obtained polymer sample. The results are shown in Table 1.

(Comparative Example 1) A compound having a thiocarbonylthio structure was prepared by using 85 parts of methyl methacrylate and 15 parts of n-butyl methacrylate as monomers.
A polymer sample was obtained in the same manner as in Example 1 except that (2-phenylpropyl) dithiobenzoate was not added. The weight average molecular weight of this polymer sample determined by GPC measurement was 800,000. Similar workability evaluation was performed using the obtained polymer sample. The results are shown in Table 1.

Comparative Example 2 Example 1 was repeated except that 30 parts of methyl methacrylate and 70 parts of n-butyl methacrylate were used as monomers and 2- (2-phenylpropyl) dithiobenzoate was not added. A polymer sample was obtained by the same operation as described above. The weight average molecular weight of this polymer sample determined by GPC was 840,000. Similar workability evaluation was performed using the obtained polymer sample. The results are shown in Table 1.

Comparative Example 3 60 parts of methyl methacrylate, 30 parts of n-butyl methacrylate and 10 parts of n-butyl acrylate were used as monomers, and 2- (2-phenylpropyl) dithiobenzoate was added. A polymer sample was obtained by the same operation as in Example 1 except that the above was not performed.
The weight average molecular weight of this polymer sample measured by GPC was 730,000. Similar workability evaluation was performed using the obtained polymer sample. The results are shown in Table 1.

Comparative Example 4 As a monomer, 60 parts of methyl methacrylate, 35 parts of n-butyl methacrylate and 5 parts of n-butyl acrylate were used, and 2- (2-phenylpropyl) dithiobenzoate was added. A polymer sample was obtained by the same operation as in Example 1 except that the above was not performed. The weight average molecular weight of this polymer sample determined by GPC was 740,000. Similar workability evaluation was performed using the obtained polymer sample. The results are shown in Table 1.

Comparative Example 5 Example 1 was repeated except that 75 parts of methyl methacrylate and 25 parts of n-lauryl methacrylate were used as monomers and 2- (2-phenylpropyl) dithiobenzoate was not added. A polymer sample was obtained by the same operation as described above. The weight average molecular weight of this polymer sample determined by GPC was 710,000. Similar workability evaluation was performed using the obtained polymer sample. The results are shown in Table 1.

Comparative Example 6 A polymer sample was obtained in the same manner as in Example 1 except that the addition of the monomer was changed as follows. First, 80 parts of methyl methacrylate was gradually added over 4 hours to prepare a polymer latex, and 10 parts of methyl methacrylate and 10 parts of n-butyl acrylate were further added.
The monomer mixture consisting of parts was added over 1 hour. Thus, a two-stage copolymer latex was obtained. The weight average molecular weight of this latex powder determined by GPC measurement was 720,000. Similar workability evaluation was performed using the obtained polymer sample. The results are shown in Table 1.

[0104]

[Table 1]

As shown in Table 1, in the examples, the evaluations of the ungelled material (fish eye), the flow mark and the air mark are all good. In Table 1, two evaluation results such as ○ / △ are
It indicates that the evaluation result of the test is in between these (for example, between ◯ and Δ). It can be seen that in each example, the transparency and the elongation at break are at the same level as in the case of using the conventional processability improver. On the other hand, Comparative Example 1 contains n-butyl methacrylate (B
Since the amount of MA) is small, there are many ungelled substances. Comparative example 2
On the contrary, the transparency is deteriorated because the BMA amount is too large. In Comparative Example 3, since the amount of the acrylic ester was as large as 10 parts, the evaluation of the flow mark and the air mark was poor.
Comparative Example 4 has the same composition as that of Example 5, but has a wide molecular weight distribution and poor flow mark and air mark evaluations. In Comparative Example 5, since the alkyl chain of the methacrylic acid ester used was too long, the flow mark and air mark evaluations were poor. Comparative Example 6 is a type of conventional processability improver composed of methyl methacrylate and acrylic acid ester, but like Comparative Example 3, the evaluation of the flow mark and air mark is poor.

Next, the molecular weight or the addition amount of the polymer sample (workability improving agent) was changed, and the flow mark, air mark and the like were evaluated.

(Example 7) The polymer sample obtained in Example 3 was added in an amount of 1.0 part per 100 parts of the vinyl chloride resin, and the workability was evaluated as described in Evaluation Method (4). The results are shown in Table 2.

Example 8 The polymer sample obtained in Example 3 was added in an amount of 8.0 parts per 100 parts of vinyl chloride resin, and the workability was evaluated as described in Evaluation Method (4). The results are shown in Table 2.

Example 9 A polymer sample was obtained in the same manner as in Example 1 except that the amount of the polymerization initiator was changed to 0.04 part. The weight average molecular weight of this polymer sample determined by GPC measurement was 1.4 million. The presence of a thiocarbonylthio group was also confirmed by NMR analysis. From the content of sulfur atoms by elemental analysis, the content of the polymer having a thiocarbonylthio group was 64%. 0.1 part of the obtained polymer sample was added per 100 parts of vinyl chloride resin, and the workability was evaluated as described in Evaluation Method (4). The results are shown in Table 2.

Example 10 The polymer sample obtained in Example 9 was added in an amount of 3.0 parts per 100 parts of vinyl chloride resin, and the workability was evaluated as described in Evaluation Method (4). The results are shown in Table 2.

Comparative Example 7 The polymer sample obtained in Example 1 was added in an amount of 0.05 part per 100 parts of vinyl chloride resin, and the workability was evaluated as described in Evaluation Method (4). The results are shown in Table 2.

Comparative Example 8 The polymer sample obtained in Example 1 was added in an amount of 12.0 parts per 100 parts of vinyl chloride resin, and the workability was evaluated as described in Evaluation Method (4). The results are shown in Table 2.

Comparative Example 9 A polymer sample was obtained by the same procedure as in Example 1 except that the amount of the polymerization initiator was 0.01 part. The weight average molecular weight of this polymer sample determined by GPC was 1.8 million. The presence of a thiocarbonylthio group was also confirmed by NMR analysis. From the content of sulfur atoms by elemental analysis, the content of the polymer having a thiocarbonylthio group was 52%. Using the obtained polymer sample, workability evaluation was performed in the same manner as in Example 1. The results are shown in Table 2.

(Comparative Example 10) The polymer sample obtained in Comparative Example 9 was added in an amount of 1.0 part per 100 parts of vinyl chloride resin, and the workability was evaluated as described in Evaluation Method (4). The results are shown in Table 2.

COMPARATIVE EXAMPLE 11 Except that 0.01 part of 2- (2-phenylpropyl) dithiobenzoate was replaced by 0.2 part of tert-dodecyl mercaptan.
A polymer sample was obtained by the same operation as in Example 1. The weight average molecular weight of this polymer sample determined by GPC was 4
It was 0,000. Using the obtained polymer sample, workability evaluation was performed as described in Evaluation method (4). The results are shown in Table 2.
Shown in.

Comparative Example 12 The polymer sample obtained in Comparative Example 11 was added in an amount of 5.0 parts per 100 parts of vinyl chloride resin, and the workability was evaluated as described in Evaluation Method (4). The results are shown in Table 2.

[0117]

[Table 2]

As shown in Table 2, Examples 7 to 9
The blending parts of the polymer sample with respect to 100 parts of vinyl chloride resin were changed to 1.0 part, 8.0 parts and 0.1 part, respectively, but it was found that good physical properties were obtained in all cases. In Examples 9 and 10, the weight average molecular weight (Mw) of the polymer sample was set to 1.4 million, which shows that the physical properties are also good in this case.

On the other hand, in Comparative Example 7, the air mark was poorly evaluated because the blending number of the polymer sample with respect to the vinyl chloride resin was as small as 0.05 part. On the contrary, in Comparative Example 8, The flow mark is poorly evaluated because it is too much as 12.0 parts. Comparative Example 9 shows that when the weight average molecular weight of the polymer sample becomes as high as 1.8 million, the evaluation of the flow mark becomes poor. In Comparative Example 10, the flow mark was attempted to be improved by reducing the number of parts of the processability improver having a too high weight average molecular weight to be mixed with the vinyl chloride resin. As a result, the evaluation of the air mark is deteriorated, which means that the flow mark and the air mark cannot be simultaneously improved. In Comparative Example 11, since the weight average molecular weight is too low, the air mark and the elongation at break are poorly evaluated. In Comparative Example 12, even if the compounding number of such a processability improver with respect to the vinyl chloride resin is increased, the physical properties are improved. Indicates that there is no improvement.

Example 11 1.0 part of the polymer sample obtained in Example 3 per 100 parts of vinyl chloride resin, Example 9
2.0 parts of the polymer sample obtained in 1. was added and the workability was evaluated as described in Evaluation Method (4). The results are shown in Table 3.

Example 12 2.0 parts of the polymer sample obtained in Example 3 per 100 parts of vinyl chloride resin, Example 9
1.0 part of the polymer sample obtained in step 1 was added, and workability evaluation was performed as described in evaluation method (4). The results are shown in Table 3.

Comparative Example 13 A polymer sample was obtained in the same manner as in Example 1 except that the amount of the polymerization initiator was 0.02 part and that 2- (2-phenylpropyl) dithiobenzoate was not added. . The weight average molecular weight of this polymer sample determined by GPC was 1.3 million. 2.0 parts of the obtained polymer sample per 100 parts of vinyl chloride resin and 1.0 part of the polymer sample obtained in Comparative Example 1 were added, and the workability was evaluated as described in Evaluation Method (4). went. The results are shown in Table 3.

Comparative Example 14 1.0 part of the polymer sample obtained in Comparative Example 13 and 2.0 parts of the polymer sample obtained in Comparative Example 1 were added per 100 parts of the vinyl chloride resin, and the evaluation method (4 ), The workability evaluation was performed. The results are shown in Table 3.

[0124]

[Table 3]

As shown in Table 3, in Examples 11 and 12, it was found that the physical properties were good even if two polymer samples having different weight average molecular weights were added.

On the other hand, in Comparative Examples 13 and 14, the air mark and the flow mark were evaluated poorly because the molecular weight distributions of the polymer samples combined were wide.

[0127]

The vinyl chloride resin composition of the present invention retains the excellent physical properties and chemical properties inherent to vinyl chloride resins. Therefore, the gelation property at the time of molding is good, the secondary workability is good, and the generation of air marks and flow marks at the time of calendering can be suppressed at the same time. Such a composition can be widely used as a packaging material by calendar processing, an agricultural vinyl sheet, and the like.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tomoki Hiiro             5-1-1, Torikai Nishi, Settsu City, Osaka Prefecture             Gaku Kogyo Co., Ltd. F-term (reference) 4J002 BD041 BD061 BD071 BD081                       BD091 BD181 BG052 BG062                       BG072 FD202                 4J011 NB04

Claims (8)

[Claims] 1. A vinyl chloride resin composition containing the following two components: (I) 100 parts by weight of vinyl chloride resin; and (II)
0.1-10 parts by weight of a processability improver for vinyl chloride resin, wherein the processability improver is methyl methacrylate 40-
Polymerization of 80% by weight, 20 to 60% by weight of a methacrylic acid ester other than methyl methacrylate, and 0 to 5% by weight of a monomer copolymerizable with the methyl methacrylate and the methacrylic acid ester is performed. The methacrylic acid ester is represented by CH ₂ ═C (CH ₃ ) COOR,
Is a hydrocarbon group having 2 to 8 carbon atoms; and the copolymer has a weight average molecular weight (Mw) of 500,000 to 1,500,000 determined by gel permeation chromatography (GPC) measurement, and The molecular weight distribution (Mw / Mn) represented by the ratio with the average molecular weight (Mn) is 1.6 or less. 2. The vinyl chloride resin composition according to claim 1, wherein the processability improver comprises a plurality of kinds of the copolymers. 3. The vinyl chloride resin composition according to claim 2, wherein the weight average molecular weights (Mw) of the plural kinds of copolymers are different by 10,000 or more. 4. The molecular weight distribution (Mw / M) of the copolymer
The vinyl chloride resin composition according to claim 1, wherein n) is 1.4 or less. 5. The weight average molecular weight (Mw) of the copolymer
Is 600,000 to 1,000,000, and the vinyl chloride resin composition according to any one of claims 1 to 4. 6. The processability-improving agent contains a copolymer having at least one thiocarbonylthio structure in one molecule in an amount of 50% or more based on all copolymers. The vinyl chloride resin composition according to any one of 1 to 5. 7. The copolymer according to claim 1, wherein the copolymer having at least one thiocarbonylthio structure in one molecule is contained in a proportion of 70% or more based on the total copolymer. The vinyl chloride resin composition described. 8. Methyl methacrylate 40 to 80% by weight,
Methacrylic acid esters other than methyl methacrylate 20-
60% by weight and 0 to 5% by weight of a monomer copolymerizable with the methyl methacrylate and the methacrylic acid ester
A processability-improving agent for vinyl chloride-based resins, which is a methacrylic copolymer obtained by polymerizing a monomer consisting of CH ₂ = C (C
H ₃ ) COOR, R is a hydrocarbon group having 2 to 8 carbon atoms, and the copolymer has a weight average molecular weight (Mw) determined by gel permeation chromatography (GPC) measurement. Molecular weight distribution (Mw / Mn) of 500,000 to 1,500,000 and represented by the ratio with the number average molecular weight (Mn)
Is 1.6 or less, a processability improver for vinyl chloride resins.