JP2003012846A - Foamable vinyl-chloride resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foamable vinyl-chloride resin composition, capable of obtaining a high foaming magnification in foam-molding, and excellent in workability such as a take-off property in extruding. SOLUTION: The foamable vinyl-chloride resin composition is composed of a vinyl chloride resin, a workability improving agent and a thermal decomposable foaming agent. The thermal decomposable agent is a (meth)acrylate ester polymer having a weight average molecular weight (Mw) of 2 million or above determined by a gel-permeation chromatography(GPC) and a molecular weight distribution (Mw/Mn) of 1.6 or below shown by a ratio of Mw to a number average molecular weight (Mn), wherein a ratio of the workability improving agent to the vinyl chloride agent of 100 pts.wt. is 1-25 pts.wt.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a foamable vinyl chloride resin composition. More specifically, it relates to a foamable vinyl chloride resin composition which is excellent in processability such as retrievability during extrusion molding and gives a foamed molded product having excellent physical properties.

[0002]

2. Description of the Related Art Vinyl chloride resin is used as a building material because it gives a molded product excellent in physical properties such as impact resistance and heat resistance and chemical properties such as solvent resistance, acid resistance and alkali resistance. It is widely used in various other fields. In recent years, the foam molding method has been attracting attention as a means for reducing the weight of vinyl chloride resin or reducing the cost of molded products, and the market has been growing the demand for molded products of vinyl chloride resin having a high expansion ratio. .

As a foam molding method for vinyl chloride resin,
Generally, a method is known in which a processability improving agent containing methyl methacrylate as a main component is used in combination with a foaming agent. Blowing agents are roughly classified into two types: volatile blowing agents and decomposable blowing agents.

Volatile blowing agents include aliphatic hydrocarbons,
Easily volatile organic solvent-based foaming agents such as aliphatic halogenated hydrocarbons are known, and when these are used, foaming at high magnification is possible.

For example, in JP-B-60-10540 and JP-B-58-40986, the boiling point of butane, dichlorofluoromethane or the like as a foaming agent is 90 ° C.
It is described that a foamed molded product having a foaming ratio as high as several tens of times can be obtained by impregnating a vinyl chloride resin with the following organic solvent or directly injecting it into an extruder during extrusion. However, such an organic solvent-based foaming agent is disadvantageous in cost because it requires facilities such as impregnation and explosion proof at the time of molding, as compared with the thermal decomposition type foaming agent.

On the other hand, when a thermal decomposition type foaming agent such as a thermal decomposition type organic foaming agent or a thermal decomposition type inorganic foaming agent is used as the foaming agent, the above equipment is not required, so that the cost is suppressed. To be However, make the surface of the molded product uniform,
Moreover, in order to keep the foam cells uniform and fine, at present, 3
It is difficult to increase the expansion ratio to about 4 times or more.

For example, Japanese Patent Publication No. 63-9540 discloses a foamable vinyl chloride resin composition containing the thermal decomposition type foaming agent and a processability improving agent. This composition is a methacrylic acid ester resin (degree of polymerization of 2,000 to 30,000,
Polymethylmethacrylate having a weight average molecular weight of 200,000 to 3,000,000), a thermal decomposition type organic foaming agent such as azodicarbonamide, a thermal decomposition type inorganic foaming agent such as sodium bicarbonate, a filler such as calcium carbonate, and an average degree of polymerization. 500-8
00 vinyl chloride resin. It is described that when molded using this expandable vinyl chloride resin composition, a foamed molded product having uniform and fine foam cells and having excellent surface uniformity and surface hardness can be obtained. The magnification is about 3 to 4 times.

Further, a foaming vinyl chloride resin composition containing a thermal decomposition type foaming agent is disclosed in JP-A-6-9813. This composition contains a methacrylic acid ester-based resin, a pyrolysis-type foaming agent having a bicarbonate of 10 μm or less, and a vinyl chloride-based resin. It is described that when molded using this vinyl chloride resin composition for foaming, a foamed molded product having uniform and fine foamed cells and having good thermal stability and weather resistance can be obtained. The expansion ratio when molded using this composition is not described in detail. Further, in general, a foamable vinyl chloride resin composition has a problem that its processability is poor when the expansion ratio is high.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a foamable vinyl chloride resin composition which has a high expansion ratio and is excellent in processability such as retrievability during extrusion molding.

[0010]

Means for Solving the Problems As a result of intensive studies on the above problems, the present inventors have used a processability improving agent having a narrow molecular weight distribution in a system using a pyrolytic foaming agent in foam molding. It was found that a composition having excellent processability such as retrievability at the time of extrusion molding and capable of improving the expansion ratio as compared with the conventionally known composition can be obtained, and the present invention has been completed.

The present invention is a foamable vinyl chloride resin composition containing a vinyl chloride resin, a processability improver, and a thermal decomposition type foaming agent, wherein the processability improver is gel permeation chromatography ( The weight average molecular weight (Mw) determined by GPC) is 2,000,000 or more, and the molecular weight distribution (Mw / Mn) represented by the ratio with the number average molecular weight (Mn).
Is a (meth) acrylic acid ester-based polymer having a ratio of 1.6 or less, and the processability improver is contained in a proportion of 1 to 25 parts by weight with respect to 100 parts by weight of the vinyl chloride resin. I will provide a.

In a preferred embodiment, the molecular weight distribution (M
w / Mn) is 1.4 or less.

In a preferred embodiment, 50% or more of a polymer having at least one thiocarbonylthio structure in one molecule is present in the (meth) acrylic acid ester-based polymer.

In a further preferred embodiment, 70% or more of the polymer having at least one thiocarbonylthio structure is present in the above molecule.

In a preferred embodiment, the pyrolytic foaming agent is a pyrolytic inorganic foaming agent, and the foaming agent is 0.1 to 25.
Includes parts by weight.

In a preferred embodiment, the pyrolytic foaming agent is a pyrolytic organic foaming agent, and the foaming agent is 0.1 to 15
Includes parts by weight.

In a preferred embodiment, the pyrolytic inorganic blowing agent is sodium bicarbonate.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The expandable vinyl chloride resin composition of the present invention uses a polymer having a narrow molecular weight distribution obtained by polymerizing a vinyl chloride resin and a monomer having a methacrylic acid ester as a main component. Processability improving agents, and pyrolytic foaming agents. The vinyl chloride resin, the processability improver, and the thermal decomposition type foaming agent contained in the composition of the present invention will be described below in order.

[Vinyl Chloride Resin] The vinyl chloride resin used in the present invention is not particularly limited, and any vinyl chloride resin commonly used may be used. The vinyl chloride resin is a resin composed of vinyl chloride units of 80 to 100% by weight and other vinyl chloride-copolymerizable monomer units of 0 to 20% by weight in view of physical and chemical properties of the molded product. Copolymers or copolymers are preferred.

Other monomers copolymerizable with the above vinyl chloride include, for example, vinyl acetate, propylene, styrene, acrylates (eg, methyl acrylate, ethyl acrylate, butyl acrylate, octyl acrylate, etc.). Alkyl acrylate having an alkyl group having 1 to 8 carbon atoms) and the like. These may be used alone or in combination of two or more.

The average degree of polymerization of the vinyl chloride resin used in the present invention is not particularly limited, but is usually 400 to 80.
It is about 0.

Specific examples of such a vinyl chloride resin include (1) polyvinyl chloride, (2) vinyl chloride monomer unit of 80% by weight or more and vinyl acetate, propylene, styrene, and acrylic acid ester. Copolymers consisting of 20% by weight or less of a monomer unit selected from the group consisting of, and (3) post-chlorinated polyvinyl chloride and the like. These may be used alone or in combination of two or more.

[Used as a processability improving agent (meta)
Acrylic ester-based (co) polymer and components constituting the (co) polymer] (Meth) acrylic ester-based polymer used as a processability improver contained in the vinyl chloride resin composition of the present invention Alternatively, a copolymer (hereinafter sometimes referred to as a (meth) acrylic acid ester-based (co) polymer) is a component used for the purpose of improving the foamability of the vinyl chloride-based resin composition.

The weight average molecular weight (Mw) determined by gel permeation chromatography (GPC) of the (meth) acrylic acid ester (co) polymer used as the processability improver is 2,000,000 or more, and The molecular weight distribution represented by the ratio (Mw / Mn) to the number average molecular weight (Mn) is 1.6 or less. When obtaining a composition having a low expansion ratio of 2-3 times, the weight average molecular weight (Mw) is 200.
In the case of obtaining a composition having a high expansion ratio of 10,000 or more, it is preferably 4,000,000 or more. The above-mentioned molecular weight distribution is preferably 1. because of the fact that a high expansion ratio can be obtained and the workability such as take-up property is excellent.
It is 5 or less. Since the foaming ratio is improved by promoting the gelation of the vinyl chloride resin, the higher the molecular weight of the (co) polymer which is the processability improving agent is, the more preferable for promoting the gelation.
However, if the molecular weight of the (co) polymer is too high, the processability such as the take-up property decreases, and as a result,
The expansion ratio of the obtained molded product tends to decrease. Therefore, the weight average molecular weight (Mw) is preferably 2 to 20 million. The weight average molecular weight (Mw) is more preferably 3,000,000 to 1.9 from the viewpoint that a molded product having a high expansion ratio and excellent processability such as take-up property can be obtained.
It is, 000,000, and more preferably 4 to 17 million. When the average molecular weight (Mw) is less than 2,000,000, sufficient foamability cannot be obtained.

The above-mentioned polymer is preferably selected from a major amount of methyl methacrylate and, if necessary, a methacrylic acid ester and an acrylic acid ester other than methyl methacrylate (hereinafter referred to as (meth) acrylic acid ester). Monomers, and, if necessary, a monomer mixture containing vinyl monomers (hereinafter referred to as vinyl monomers) copolymerizable with the methyl methacrylate and (meth) acrylic acid ester (hereinafter referred to as It is obtained by polymerizing a monomer mixture).

Examples of the methacrylic acid ester other than the above methyl methacrylate include ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate and the like. Examples of the acrylate ester include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate.
These methacrylic acid esters and acrylic acid esters other than methyl methacrylate may be used alone.
You may use it in combination of 2 or more types.

Examples of the vinyl-based monomer include aromatic vinyl such as styrene and α-methylstyrene, and unsaturated nitrile such as acrylonitrile.
These may be used alone or in combination of two or more.

The content of methyl methacrylate in the above monomer mixture was 50 to 100% by weight based on the total weight of the monomers, and the obtained (co) polymer was used as a processability improver. In view of foamability in this case, the proportion is preferably 50 to 90% by weight, more preferably 60 to 85% by weight.
The content of the (meth) acrylic acid ester is 0 to 50% by weight of the total weight of the monomers, and the content of the obtained (co) polymer is a vinyl chloride resin when used as a processability improver. In terms of compatibility, the proportion is preferably 0 to 40% by weight, more preferably 0 to 35% by weight. The content of the vinyl-based monomer is 0 to 20% by weight based on the total weight of the monomers, and the content of the obtained (co) polymer with the vinyl chloride resin is used as a processability improver. From the viewpoint of compatibility, the proportion is preferably 0 to 10% by weight, more preferably 0 to 5% by weight.

When the content of methyl methacrylate in the above monomer mixture is less than 50% by weight, that is, the ratio of the monomers other than the above methyl methacrylate selected from methacrylic acid ester and acrylic acid ester is 50% by weight. %
If it exceeds, the processability and foamability of the obtained (co) polymer may decrease when used as a processability improver. When the proportion of the vinyl-based monomer exceeds 20% by weight, the gelation property and foamability of the (co) polymer when used as a processability improver tend to be lowered.

[Compound Having Thiocarbonylthio Structure] The (co) polymer having a molecular weight distribution of 1.6 or less, which is used as a processability improver, can be synthesized by 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 / 05099, International Patent WO99 / 31
144, Macromolecules 1998 31
Volume 16, pages 5559-5562, Macromol
ecules 1999 Volume 32 No. 6 2071-2074
Page, Polym. Prepr. 1999 Volume 40 2
No. 342-343, Polym. Prepr. 1
999, 40, No. 2, pp. 397-398, Poly
m. Prepr. 1999 Volume 40 No. 2 899-900
Page, Polym. Prepr. 1999 Volume 40 2
Issue 1080-8081, Macromolecule
les 1999 32, No. 21, pages 6977-6980, Macromolecules 2000, 33 33 2
No. 243-245, Macromol. Sym
p. 2000, 150, pp. 33-38.

The above (meth) acrylic acid ester-based (co)
As the compound having a thiocarbonylthio structure, which is preferably used in the production of a polymer, the compounds described in the above literature can be used, and for example, compounds represented by the general formula (1)

[0032]

[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)

[0034]

[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:

[0037]

[Chemical 3]

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

Further, as described above, R ¹ may be a high molecular weight compound, and examples thereof 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:

[0041]

[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:

[0044]

[Chemical 5]

(In the formula, n is an integer of 1 or more and r is an integer of 0 or more). In the above formula, n and r are preferably 500 or less in terms 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:

[0047]

[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 ends can be easily produced, and therefore, the thiocarbonylthio structure represented by the general formula (3) is provided at both ends. Compounds having are preferred:

[0050]

[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 from the viewpoint of availability of the compound, R ³ preferably has 1 to 20 carbon atoms. In terms of availability, the following formula:

[0053]

[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:

[0056]

[Chemical 9]

(In the formula, n is an integer of 1 or more and r is an integer of 0 or more). In the above formula, n and r are preferably 500 or less in terms 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:

[0059]

[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,
The chain transfer constant is preferably 1 or more, and more preferably 10 or more, from the viewpoint of good processability such as removability during extrusion molding and foamability.

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

[Used as a processability improving agent (meta)
Outline of Preparation of Acrylic Ester-Based (Co) Polymer] In the present invention, a major amount of methyl methacrylate and, if necessary, a monomer selected from the above (meth) acrylic acid ester, and further, if necessary. A (meth) acrylic acid ester-based (co) polymer is obtained by polymerizing a monomer mixture containing the vinyl-based monomer. Preferably,
By radical polymerization using the above-mentioned compound having a thiocarbonylthio structure, a (meth) acrylic acid ester-based (co) polymer having a thiocarbonylthio structure introduced can be obtained.

In the polymerization reaction using the above-mentioned methyl methacrylate as a main component and, if necessary, a monomer mixture containing a (meth) acrylic acid ester, a compound having a thiocarbonylthio structure is reversibly added as a chain transfer agent. Elimination chain transfer (RAFT) polymerization occurs to form a methacrylic (co) polymer. For example, as shown in the scheme below, the compound (1) having a thiocarbonylthio structure is
When the methyl methacrylate (X) and the (meth) acrylic acid ester (Y) are reacted, a (meth) acrylic acid ester-based copolymer (4) is formed. When the compound (2) having a thiocarbonylthio structure is used, the (meth) acrylic acid ester-based copolymer (5) is formed.

[0065]

[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 ) represents a polymer chain containing methyl methacrylate (X) and (meth) acrylic acid ester (Y) as copolymerization components. Depending on the amounts of X and Y charged and the reaction conditions, n
₁ and n ₂ change. 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 (meth) acrylic acid ester-based copolymer is formed.

[Solvent and Additive Used for Polymerization] The type of radical polymerization using the monomer mixture in the presence of the compound having the thiocarbonylthio structure is not particularly limited. It is possible to apply commonly used methods such as solution polymerization, emulsion polymerization, suspension polymerization, and bulk polymerization. A compound having a thiocarbonyl structure may be present in these polymerization reaction systems.

In carrying out the radical polymerization, additives for polymerization usually used in the art are 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 additives for polymerization, the dispersion emulsifier is
When performing emulsion polymerization, suspension polymerization, or fine suspension polymerization,
It is added for the purpose of improving the dispersion stability of the (meth) acrylic acid ester-based monomer in an aqueous emulsion or suspension and efficiently performing the polymerization. Dispersion emulsifiers include, but are not limited to, the following emulsifiers: fatty acid salts, alkyl sulfate salts, alkylbenzene sulfonate salts, alkyl phosphate ester salts, sulfosuccinic acid diester salts (eg, dioctyl sodium sulfosuccinate), and the like. Anionic surfactants; nonionic surfactants such as polyoxyethylene alkyl ethers and polyoxyethylene fatty acid esters. 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 or the like is used. For example, a usual inorganic polymerization initiator such as persulfate, an organic peroxide, an azo compound or the like is used alone, or with the above compound, a sulfite, a thiosulfate, a first metal salt, sodium formaldehyde sulfoxylate. In combination with a reducing agent such as
It can also be used as a redox polymerization initiator. As the polymerization initiator, persulfates such as sodium persulfate, potassium persulfate and ammonium persulfate, organic peroxides such as t-butyl hydroperoxide, cumene hydroperoxide, benzoyl peroxide and lauroyl peroxide are preferable. .

[Preparation of (meth) acrylic acid ester-based (co) polymer] The (meth) acrylic acid ester-based (co) polymer used as the processability improver is, for example, as described above, methacrylic acid. Methyl 50-100% by weight,
And, if necessary, the above (meth) acrylic acid ester 5
It can be obtained by polymerizing a monomer mixture containing 0% by weight or less and, if necessary, 20% by weight or less of the above vinyl-based monomer. Polymerization is preferably carried out using the compound having the above thiocarbonylthio structure. The embodiment of the 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 adding 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.

When the above emulsion polymerization is used, for example,
The above-mentioned monomer mixture is emulsion polymerized using a suitable dispersion medium, an emulsifier and a polymerization initiator. The dispersion medium used is usually water.

The emulsion polymerization may be carried out in two steps or more. When carrying out the two-step polymerization or more, by adding the monomer after the second step after confirming that the first-step polymerization is completed, Polymerization in each stage can be carried out without mixing with the above monomer.

The temperature, time, etc. during the polymerization reaction are not particularly limited, and may be appropriately adjusted so as to have a desired specific viscosity and particle diameter depending on the purpose of use.

The particles in the (co) polymer latex thus obtained usually have an average particle size of 10 to 300 n.
It is about m. The particles are taken out from the latex by salting out, coagulating by adding an ordinary electrolyte, spraying in hot air, or the like. If necessary, washing, dehydration, drying and the like are carried out by usual methods. The (co) polymer particles obtained by the above operation are usually powdery particles having an average particle diameter of 30 to 300 μm when blended with a vinyl chloride resin or a foamable vinyl chloride resin as a processability improver. Is preferred.

In this manner, radical polymerization of the monomer mixture in the presence of the above-mentioned compound having a thiocarbonylthio structure is carried out to introduce a (meth) acrylic acid ester system (copolymer) having a thiocarbonylthio structure introduced therein. ) A polymer is obtained.

Among the (meth) acrylic acid ester-based (co) polymers, the copolymer having a thiocarbonylthio structure is particularly preferably a vinyl chloride resin, a stabilizer, and a stabilizer when mixed with various additives described below. Compatibility with additives such as lubricants is improved, and processability such as take-up property during extrusion molding is also improved. Therefore, from the viewpoint of improving the physical properties of the vinyl chloride resin composition of the present invention, the above (co) polymer preferably has at least 50% of a polymer having at least one thiocarbonylthio structure in one molecule. More preferably 70% or more. The ratio here is based on the number of polymer molecules (the number of moles).

From the above viewpoints, the processability improver of the present invention is preferably a (co) polymer having a plurality of thiocarbonyl structures in one molecule, and having a thiocarbonylthio structure at both ends (copolymer). ) Polymers are more preferred.

[Pyrolysis type foaming agent] Examples of the pyrolysis type foaming agent used in the composition of the present invention include a pyrolysis type inorganic foaming agent and a pyrolysis type organic foaming agent. These may be used alone or in combination of two or more.

The thermal decomposition type inorganic foaming agent is not particularly limited, and examples thereof include sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, sodium carbonate and ammonium carbonate. These may be used alone or in combination of two or more. Of these, sodium bicarbonate is preferable from the viewpoint of foaming efficiency and cost.

The thermal decomposition type organic foaming agent is not particularly limited. For example, azodicarbonamide, azobisisobutyronitrile, barium azodicarboxylate, N, N'-
Dinitrosopentamethylenetetramine, 4,4'-oxybis (benzenesulfonylhydrazide), paratoluenesulfonylhydrazide, hydrazodicarbonamide, isopropyl hydrazodicarboxylate, 5-phenyltetrazole, trihydrazinotriazine, acetone paratoluenesulfonylhydrazone, Paratoluenesulfonyl semicarbazide, paratoluenesulfonyl azide, 2,4-toluene disulfonyl hydrazide, diazoaminobenzene, N, N'-dimethyl-N, N'-
Included are dinitrosoterephthalamide, trinitrosomethylenetriamine, nitroguanidine, nitrourea, and urea. These may be used alone or in combination of two or more. Azodicarbonamide, 4,4′-oxybis (benzenesulfonylhydrazide) and a mixture thereof are preferable in view of the shape and processability of the foamed molded product to be obtained. Also, depending on the thermal decomposition type organic blowing agent used,
A foaming aid may be used as appropriate.

[Vinyl Chloride Resin Composition] The expandable vinyl chloride resin composition of the present invention contains a vinyl chloride resin, a processability improver, a thermal decomposition type foaming agent and, if necessary, various additives. .

In the composition of the present invention, the content of the processability improving agent is 1 with respect to 100 parts by weight of the vinyl chloride resin.
To 25 parts by weight, preferably 4 to 25 parts by weight, more preferably 6 to 20 parts by weight. When the amount of the processability improver is less than 1 part by weight, the effect of adding the processability improver cannot be sufficiently obtained, and when the amount exceeds 25 parts by weight, the excellent mechanical properties of the vinyl chloride resin are obtained. Is damaged.

In the composition of the present invention, the content of the thermal decomposition type foaming agent is appropriately determined according to the kind of the foaming agent and the purpose of use of the composition. Usually, the above vinyl chloride resin 1
In the case of the thermal decomposition type inorganic foaming agent, 0.
It is contained in a proportion of 1 to 25 parts by weight, and in the case of a pyrolytic organic foaming agent, it is contained in a proportion of 0.1 to 15 parts by weight. When the content of the thermal decomposition type inorganic foaming agent is less than 0.1 part by weight, a molded product having a sufficient expansion ratio cannot be obtained, and when it exceeds 25 parts by weight, it is difficult to obtain a uniform foamed molded product. In the case of the thermal decomposition type organic foaming agent, if the content is less than 0.1 parts by weight, a molded product having a sufficient expansion ratio cannot be obtained, and if it exceeds 15 parts by weight, a uniform foamed molded product is obtained. Hard to get.

The content of the heat-decomposable foaming agent may be changed according to the content of the processability improver in consideration of the shape of the obtained molded product. For example, foaming ratio 2-3
In order to obtain a doubled good molded product, the processability improving agent is added in an amount of about 6 parts by weight and the thermal decomposition type blowing agent is used in an amount of 1 to 2 parts by weight with respect to 100 parts by weight of the vinyl chloride resin. It is preferable to contain it. Further, in order to obtain a good highly foamed molded product having an expansion ratio of 5 times or more, about 20 parts by weight of a processability improving agent and 4 parts by weight of a thermal decomposition type blowing agent are added to 100 parts by weight of the vinyl chloride resin. It is preferable to contain it in a ratio of -18 parts by weight.

In the expandable vinyl chloride resin composition of the present invention, if necessary, other additives such as stabilizers, lubricants, impact resistance enhancers, plasticizers, colorants, and fillers may be used alone or in combination with 2.
You may make it contain in combination of 1 or more types.

A desired molded product is produced using the expandable vinyl chloride resin composition of the present invention. For example, after mixing the vinyl chloride resin, the processability improver, the thermal decomposition type foaming agent, and other additives as necessary, at an appropriate temperature,
It is molded by melt-kneading with a melt-kneader such as a single-screw or twin-screw extruder. A molding method of the expandable vinyl chloride resin composition of the present invention is not particularly limited, and a generally used molding method, for example, an extrusion molding method can be applied.

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

[0090]

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

The methods for evaluating the physical properties used in the examples and comparative examples are summarized below.

(I) 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-806 and K-805 (polystyrene gel), mobile phase: chloroform. The number average molecular weight and the like were calculated in terms of polystyrene.

(Ii) The polymerization conversion rate was calculated by the following equation. Polymerization conversion rate (%) = {amount of polymerization produced / amount of charged monomer} ×
100

(Iii) Thiocarbonyl To identify the thio structure, VARIAN NMR (Gemini-300) was used.
Was used to prepare and measure a sample solution using CDCl ₃ (deuterated chloroform) as a deuterated solvent.

(Iv) Thiocarbonyl The content of the polymer having a thio structure was calculated by the following method. First, the total sulfur content in a sample is subjected to elemental analysis (using an oxygen flask combustion method; hydrogen peroxide water is used as an absorbing solution, and measured by ion chromatography; DX-500 manufactured by Dionex).
It was quantified by GP40, ED40). Next, the thiocarbonylthio structure content was calculated from the obtained sulfur concentration based on the molecular weight of each sample obtained by the above GPC.

(V) The expansion ratio was measured as follows: of a plate-shaped molded product (foam molded product of a vinyl chloride resin composition) obtained by extrusion molding under the following conditions: The specific gravity was measured. Separately from this, a vinyl chloride resin composition containing no foaming agent was molded under the same conditions, and the specific gravity of the obtained molded product (non-foamed molded product) was measured. Using these measured values, the expansion ratio was calculated from the following formula. Expansion ratio = (specific gravity of non-foamed molded product of vinyl chloride resin composition) / (specific gravity of foamed molded product of vinyl chloride resin composition)

The specifications and molding conditions of the extruder used for the above extrusion molding are shown below. Extruder specifications: CINCINNATI MILACRON
Conical extruder CMT-45 manufactured by Co., Ltd., molding temperature: chamber 1 / chamber 2 / chamber 3 / adapter / die / screw = 150/160/170/175/1
90/120 (° C), screw rotation speed: 20 rpm,
Discharge rate: 60 kg / hr, cooling water temperature: 15 ° C., die shape: width 180 mm × thickness 10 mm (Selka method).

(Vi) In the workability evaluation, the motor load, the torque, and the stability in the take-off machine obtained in the above extrusion molding were used as evaluation criteria, and the following criteria were used for the evaluation. ◯: Good pick-up, good appearance of molded body. Δ: Clogging occurs in the cooling former part, and catching and slippage occur in the take-up machine. X: Poor take-off, cracking on the surface of the molded product and on the corners.

(Vii) Regarding the cell morphology of the obtained molded body, the molded body was cut in a direction perpendicular to the extrusion direction,
The cut surface and the appearance of the molded body were visually observed and judged according to the following criteria. ◯: The cell structure is uniform and the appearance is excellent. Δ: The appearance of the molded product is not particularly problematic, but broken cells are scattered in the observation of the cut surface (coalescence of cells and breakage of cells are recognized). X: Most of the cells are crushed and the appearance is poor.

(Example 1) In an 8 liter reactor equipped with a stirrer, 0.7 part of sodium dioctyl sulfosuccinate dissolved in water as an emulsifier was placed, and the amount of water contained in the auxiliary raw material added in the subsequent step was also added. 200 in total
Water was added so that it became a part. After oxygen was removed by circulating nitrogen in the reactor, the content was heated to 70 ° C. with stirring. Next, 68 parts of methyl methacrylate (hereinafter referred to as MMA), 12 parts of butyl acrylate (hereinafter referred to as BA), and 2- (2-phenylpropyl) dithiobenzoate, which is a compound having a thiocarbonylthio structure, were placed in the reactor. (Hereinafter referred to as CTA) 0.
Add the first stage monomer mixture consisting of 01 parts at once,
Next, 0.01 part of potassium persulfate was added as a polymerization initiator, and stirring was continued for 8 hours. Then, the second stage monomer mixture consisting of 6 parts of MMA and 14 parts of BA was added dropwise at a rate of about 30 parts per hour. After dripping, add 2 contents
The temperature was maintained at 70 ° C. for 0 hour and then cooled to obtain a latex.

The polymerization conversion rate of the copolymer in the latex was 99.5%. The obtained latex was salted out and coagulated with an aqueous calcium chloride solution, heat-treated at a temperature of 90 ° C., and then filtered using a centrifugal dehydrator. The dehydrated cake of the obtained copolymer was washed with water in an amount about the same as the weight of the resin, and dried in a parallel-flow dryer at 50 ° C. for 15 hours to obtain a powdery polymer sample (1). It was The weight average molecular weight (Mw) of the obtained polymer sample (1) was 2.8 million, the molecular weight distribution (Mw / Mn) was 1.27, and the content of the polymer having a thiocarbonylthio structure by elemental analysis was It was 98%.

Next, polyvinyl chloride (Kanefuchi Chemical Industry Co., Ltd., Kanevinyl S-1007, average degree of polymerization 68)
0) 100 parts to the above polymer sample (1) 6.0 parts, calcium carbonate (filler) 6.0 parts, titanium oxide (filler and UV absorber) 2.0 parts, octyl tin mercapto stabilizer (Di-n-octyltin bis (mercaptoacetic acid isooctyl ester) salt) (Nitto Kasei Co., TVS #
8831) 2.0 parts, calcium stearate (lubricant)
0.6 part, hydroxystearic acid (lubricant; manufactured by Henkel, LOXIOL G-21) 0.1 part, fatty acid alcohol dibasic ester (lubricant; manufactured by Henkel, LOXI
OL G-60) 0.9 parts, and polyethylene wax (lubricant; Allied Chemical Co., ACPE-617).
A) 0.6 part was mixed with a 300-liter mixer, the internal temperature was raised to 110 ° C., and after cooling, 6.0 parts of sodium bicarbonate (hereinafter referred to as SBC) was further used as a pyrolytic inorganic foaming agent. Blended to obtain a powdery mixture. The obtained powdery mixture was molded with a CMT-45 extruder and cut to obtain a plate-shaped foamed molded product. As for the workability evaluation, its take-up property was evaluated. Further, the cell morphology of the obtained foamed molded product was evaluated and the expansion ratio was measured. The results are shown in Table 1.

Examples 2 to 4 2- (2-phenylpropyl) dithiobenzoate (CTA) was added to 0.0
Polymer samples (2) to (4) were each prepared in the same manner as in Example 1 except that the amount of each component was 07 parts, 0.005 parts, and 0.004 parts, and that potassium persulfate was 0.005 parts. Then, each physical property value was measured. Further, using the obtained polymer samples (2) to (4), each was mixed with polyvinyl chloride in the same manner as in Example 1 to obtain a foamed molded product, and the above evaluation was performed. The results are shown in Table 1.

(Comparative Examples 1 to 3) No 2- (2-phenylpropyl) dithiobenzoate (CTA) was added, and potassium persulfate was added in an amount of 0.1 part and 0.0, respectively.
Polymer samples (5) to (7) were obtained in the same manner as in Example 1 except that the amounts were 5 parts and 0.0005 parts, and the respective physical properties were measured. Further, using the obtained polymer samples (5) to (7), each was mixed with polyvinyl chloride in the same manner as in Example 1 to obtain a foamed molded product, and the above evaluation was performed. The results are shown in Table 1.

[0105]

[Table 1]

From the results in Table 1, the weight average molecular weight (Mw)
Is 2 million or more and the molecular weight distribution (Mw / Mn)
It can be seen that the use of the polymer samples (1) to (4) having a ratio of 1.6 or less makes it possible to obtain a composition having good foamability. When polymer samples (5) to (7) having a molecular weight distribution (Mw / Mn) of more than 1.6 were used, no sufficient foaming property was obtained. Since the polymer sample (5) had a weight average molecular weight of 2,000,000 or less, the foamability was low, and the cell morphology of the molded product was somewhat poor. The polymer sample (7) has a high weight average molecular weight of 20 million, but has a molecular weight distribution of 1.7.
Met. In general, the larger the molecular weight, the higher the expansion ratio. However, in this polymer sample (7), the expansion ratio was low because the molecular weight distribution was wide despite the high molecular weight. Further, the take-up property during molding was poor, and the cell morphology of the obtained molded product was also poor.

(Examples 5 to 7) The polymer sample (2) obtained in Example 2 was evaluated for the difference in foamability when the content in the vinyl chloride resin composition was changed. That is, the polymer sample (2) obtained in Example 2 had 12 parts and 18 parts, respectively, with respect to 100 parts of polyvinyl chloride.
A molded product was obtained in the same manner as in Example 1 except that the number of parts and the number of parts were set to 3, and the removability, cell morphology, and foamability were evaluated. The results are shown in Table 2.

Comparative Example 4 A molded product was obtained in the same manner as in Example 1 except that the polymer sample (2) obtained in Example 2 had 30 parts by weight per 100 parts of polyvinyl chloride. , Take-off property, cell morphology, and foaming property were evaluated. The results are shown in Table 2.

[0109]

[Table 2]

From the results shown in Table 2, it can be seen that in Examples 2 and 5 to 7, molded articles having good foaming properties and good cell morphology and retrievability were obtained. In Comparative Example 4, it can be seen that, because the amount of the polymer sample is too large, good cell morphology and take-up property (workability) cannot be obtained.

(Example 8) Polyvinyl chloride (Kanefuchi Chemical Industry Co., Ltd., Kanevinyl S-1007, average degree of polymerization: 6)
80) 100 parts to the above polymer sample (2) 6.0 parts, calcium carbonate 6.0 parts, titanium oxide 2.0 parts, octyl tin mercapto stabilizer (di-n-octyl tin bis (mercapto acetic acid iso Octyl ester) salt) (Nitto Kasei Co., TVS # 8831) 2.0 parts, calcium stearate 0.6 part, hydroxystearic acid (Henkel Co., LOXIOL G-21) 0.1 part, fatty acid alcohol dibasic Ester (made by Henkel, LOXIOL
G-60) 0.9 part, and polyethylene wax (Allied Chemical Co., ACPE-617A) 0.6
Parts are mixed with a 300 liter mixer and the internal temperature is 110 ° C.
After the temperature was raised to and cooled, 2.0 parts of sodium bicarbonate (SBC) was further added as a thermal decomposition type inorganic foaming agent to obtain a powder compound. The obtained powder compound was molded with a CMT-45 extruder, and the workability was evaluated for its take-up property. Further, the cell morphology of the obtained foamed molded product was evaluated and the expansion ratio was measured.
The results are shown in Table 3.

(Example 9) As a thermally decomposable foaming agent, azodicarbonamide (ADCA), which is an organic foaming agent, was added in an amount of 0.
2 parts and inorganic blowing agent sodium bicarbonate (SB
A molded product was obtained in the same manner as in Example 8 except that 1.8 parts of C) was used, and the foamability was evaluated. The results are shown in Table 3.

(Examples 10 and 11) A molded product was obtained in the same manner as in Example 8 except that 8 parts and 20 parts of sodium bicarbonate (SBC) were used as the thermal decomposition type foaming agent, and the foamability was improved. Was evaluated. The results are shown in Table 3.

Examples 12 to 14 Polymer sample (2) was used as 18 parts, and sodium bicarbonate (SBC) was added as 4 parts each.
Example 10, except that 10 parts, 10 parts, and 20 parts were used
A molded product was obtained in the same manner as in, and the foamability was evaluated. The results are shown in Table 3.

Comparative Example 5 Sodium Bicarbonate (SBC)
A molded product was obtained in the same manner as in Example 8 except that 30 parts of was used, and the foamability was evaluated. The results are shown in Table 3.

Comparative Example 6 A molded product was obtained in the same manner as in Example 8 except that the polymer sample (2) was 18 parts and sodium bicarbonate (SBC) was 30 parts, and the foamability was evaluated. I went. The results are shown in Table 3.

[0117]

[Table 3]

From the results shown in Table 3, it was found that the compositions in which the thermal decomposition type inorganic foaming agent and / or the thermal decomposition type organic foaming agent were blended in various proportions as in Examples 8 to 14 had good foamability. A molded body having a good cell morphology and retrievability is obtained. However, as in Comparative Examples 5 and 6, it can be seen that when the proportion of the foaming agent is too large, sufficient foamability cannot be obtained.

[0119]

EFFECTS OF THE INVENTION The expandable vinyl chloride resin composition of the present invention provides a foamed molded product having a good cell shape and has good processability represented by the take-up property during molding. Such a composition is widely used in various fields such as foamed molded articles and sheets. For example, it is suitable for building materials such as foam siding boards and pipes.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08L 33:06) (72) Inventor Tomoki Hiseki 5-1-1, Torigai Nishi, Settsu City, Osaka Pref. Gaku Kogyo Co., Ltd. F-term (reference) 2E001 DH01 FA04 FA51 GA01 GA07 GA77 HA01 HA05 HA14 HA20 HB02 HB03 HB07 HD11 LA06 2E162 AA01 CA00 CA11 CA12 4F074 AA17 AA35 AA48 AB01 AC17 AC26 AD09 AD10 AD11 AD18 AG20 BA03 BD1 DA13 BD50 4 BD071 BD081 BD091 BG042 BG052 BG062 DE206 DE226 DE246 EQ016 EQ026 ER026 ES006 ET016 EU006 EU186 EV216 EV286 FD326

Claims (7)

[Claims] 1. A foamable vinyl chloride resin composition containing a vinyl chloride resin, a processability improver, and a thermal decomposition type foaming agent, wherein the processability improver is gel permeation chromatography (GP).
C) The weight average molecular weight (Mw) determined by measurement is 200.
10,000 or more and the molecular weight distribution (Mw / Mn) represented by the ratio with the number average molecular weight (Mn) is 1.6 or less (meta).
A composition which is an acrylic acid ester polymer and contains the processability improving agent in a proportion of 1 to 25 parts by weight with respect to 100 parts by weight of the vinyl chloride resin. 2. The molecular weight distribution (Mw / Mn) is 1.4.
The expandable vinyl chloride resin composition according to claim 1, which is as follows. 3. The (meth) acrylic acid ester-based polymer contains 50% or more of a polymer having at least one thiocarbonylthio structure in one molecule.
Alternatively, the expandable vinyl chloride resin composition according to item 2. 4. The expandable vinyl chloride resin composition according to claim 3, wherein 70% or more of a polymer having at least one thiocarbonylthio structure is present in the molecule. 5. The expandable vinyl chloride according to claim 1, wherein the pyrolytic foaming agent is a pyrolytic inorganic foaming agent, and the foaming agent is contained in an amount of 0.1 to 25 parts by weight. -Based resin composition. 6. The expandable vinyl chloride according to claim 1, wherein the pyrolytic foaming agent is a pyrolytic organic foaming agent, and the foaming agent is contained in an amount of 0.1 to 15 parts by weight. -Based resin composition. 7. The expandable vinyl chloride resin composition according to claim 5, wherein the thermally decomposable inorganic foaming agent is sodium bicarbonate.