JPH0859873A - Vinyl chloride resin composition - Google Patents

Abstract

PURPOSE: To provide a vinyl chloride resin composition which can be molded without overloading the molding machine and can give a foam having a high expansion ratio and a fine cellular structure by mining a vinyl chloride resin with a specified urea compound and a heat-decomposable inorganic blowing agent. CONSTITUTION: This composition comprises 100 pts.wt. vinyl chloride resin of an average degree of polymerization of 400-1000, 0.1-10 pts.wt. urea compound of the formula: R<1> NHCONHR<2> (wherein R<1> and R<2> are each 1-23C alkyl or phenyl), 0.2-5 pts.wt. heat-decomposable inorganic blowing agent, and optionaly additives such as a polymethyl methacrylate processing aid, a heat stabilizer, an antioxidant, an antistatic agent, an ultraviolet absorber, a lubricant, a filler, a plasticizer and a pigment.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a vinyl chloride resin composition.

[0002]

2. Description of the Related Art Conventionally, vinyl chloride resin has been used for impact resistance,
It has been widely used in building materials because of its excellent physical properties such as heat resistance; chemical properties such as solvent resistance, acid resistance, and alkali resistance. However, its use as a foam was further developed. Are used in a wider variety of applications.

Such a vinyl chloride resin foam molded article generally uses a pyrolytic inorganic or organic foaming agent,
It is manufactured by extrusion. As a foaming agent, a heat-decomposable organic foaming agent made of an azo compound and a heat-decomposable inorganic foaming agent made of sodium bicarbonate are used in combination, and further a methacrylic acid ester resin (processing aid) and calcium carbonate, talc, clay, A highly foamable vinyl chloride resin composition containing a filler such as asbestos or silica has been disclosed (Japanese Patent Publication No. 63-9540).

From the above vinyl chloride resin composition, a foamed molded product having a uniform and fine cell structure, a skin layer having excellent surface gloss and a high surface hardness can be obtained. At a high magnification of 5 times or more, the foam cells became coarse and it was difficult to maintain a uniform and fine cell structure. Further, in the case of a molded product having a low expansion ratio such that a uniform and fine cell structure can be maintained, there is a problem that an excessive load is applied to a molding machine at the time of extrusion molding, and molding sometimes becomes impossible.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and an object thereof is to easily perform molding without imposing an excessive load on a molding machine and to obtain a uniform foaming ratio even at a high expansion ratio. It is an object of the present invention to provide a vinyl chloride resin composition capable of obtaining a foamed molded product having a fine cell structure.

[0006]

The vinyl chloride resin composition of the present invention comprises a vinyl chloride resin (a), a urea compound (b) and a thermal decomposition type inorganic foaming agent (c).

As the vinyl chloride resin (a), those conventionally known as foam moldings can be used. For example, a homopolymer of vinyl chloride or a polymer other than vinyl chloride and vinyl chloride can be used. Copolymers with monomers, graft copolymers obtained by grafting vinyl chloride onto polymers other than vinyl chloride; chlorinated chloride obtained by post-chlorinating these (co) polymers by a conventionally known method. Vinyl-based resin; a mixture of the (co) polymer and chlorinated vinyl chloride-based resin, and the like.

The polymerizable monomer other than vinyl chloride is not particularly limited as long as it has a reactive double bond, and for example, α-, such as ethylene, propylene and butylene.
Olefin; Vinyl acetates such as vinyl acetate and vinyl propionate; Vinyl ethers such as butyl vinyl ether and cetyl vinyl ether; Methyl acrylate
Acrylic acid esters such as ethyl acrylate; Methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, phenyl methacrylate; styrene, α
-Aromatic vinyls such as methylstyrene; vinyl halides such as vinylidene chloride and vinyl fluoride; N- such as N-phenylmaleimide and N-cyclohexylmaleimide
Substituted maleimides and the like may be used alone or in combination of two or more.

The polymer other than vinyl chloride used in the graft copolymer is not particularly limited, and examples thereof include ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-carbon monoxide copolymer, ethylene. -Ethyl acrylate copolymer, ethylene-ethyl acrylate-carbon monoxide copolymer, ethylene-methyl methacrylate copolymer, ethylene-propylene copolymer, acrylonitrile-butadiene copolymer, polyurethane resin, chlorinated polyethylene resin, chlorine And the like. These may be used alone or in combination of two or more.

When the average degree of polymerization of the vinyl chloride resin is small, the mechanical properties of the resulting molded article, particularly impact resistance, is low, and when it is large, the melt viscosity at the time of molding becomes high and molding becomes difficult. Since the foam cells will be non-uniform,
400-1000 is preferable, More preferably, it is 500-
800.

The urea compound (b) has the general formula R ¹ N
It is represented by HCONHR ² . In the formula, R ¹ and R ² represent an alkyl group or a phenyl group, and may be the same or different. When the alkyl group or phenyl group represented by R ¹ or R ² has a large number of carbon atoms, the compatibility with a vinyl chloride resin decreases, leading to poor gelation and foaming failure. Therefore, the carbon number is limited to 1 to 23 carbon atoms. And preferably 7 to 21.

Examples of the urea compound (b) include N-butyl-N'-myristyl urea and N-butyl-
N'-stearyl urea, N-butyl-N'-behenyl urea,
N-butyl-N'-phenylurea, N, N-dimyristylurea, N-myristyl-N'-stearylurea, N-myristyl-N'-behenylurea, N-myristyl-N'-phenylurea, N, N '-Distearyl urea, N-stearyl-N'-behenyl urea, N-stearyl-N'-phenyl urea, N, N'-dibehenyl urea, N-behenyl-N'-phenyl urea, N, N'-diphenyl Examples thereof include urea, and these may be used alone or in combination of two or more kinds.

In the vinyl chloride resin composition of the present invention, when the amount of the urea compound (b) added is reduced, the effect of stabilizing the foam cells is lowered, and a uniform and fine cell structure can be maintained. It becomes difficult, and if the number increases, defective gelation causes foaming defects such as foam breaking. Therefore, it is limited to 0.1 to 10 parts by weight, preferably 0.5 to 10 parts by weight, relative to 100 parts by weight of the vinyl chloride resin (a). 3 parts by weight.

The thermal decomposition type inorganic foaming agent (c) is as follows:
Examples thereof include sodium bicarbonate, ammonium bicarbonate, ammonium carbonate, etc. Of these, sodium bicarbonate is preferred from the viewpoints of toxicity and foaming properties.

In the vinyl chloride resin composition of the present invention, if the amount of the thermal decomposition type inorganic foaming agent (c) is reduced, it becomes difficult to obtain a predetermined expansion ratio, and if it is increased, foaming defects such as foam breakage occur. Therefore, it is limited to 0.2 to 5 parts by weight with respect to 100 parts by weight of the vinyl chloride resin (a).

When molding the vinyl chloride resin composition of the present invention, a polymethylmethacrylate-based processing aid, if necessary, in order to improve moldability, thermal stability and the like,
A heat stabilizer, an antioxidant, an antistatic agent, an ultraviolet absorber, a lubricant, a filler, a flame retardant, a plasticizer, a pigment, a paint and the like may be added appropriately.

Examples of the heat stabilizers include tin-based stabilizers such as dibutyltin malate and dibutyltin mercapto; organometallic soap-based stabilizers such as calcium stearate, barium stearate and zinc stearate; and lead compound-based heat stabilizers. Can be mentioned.

Examples of the lubricant include aliphatic hydrocarbons such as paraffin wax and polyethylene wax; higher aliphatic alcohols such as stearyl alcohol; higher fatty acid such as stearic acid and hydroxystearic acid;
Examples thereof include monoalcohol fatty acid ester-based agents such as butyl stearate; and polyhydric alcohol fatty acid ester-based lubricants such as glycerin monostearate and glycerin tristearate.

Examples of the above-mentioned filler include calcium carbonate, clay, mica, glass fiber and the like, and examples of the above-mentioned flame retardant include halogen-based, phosphorus-based, metal oxide-based flame retardants such as antimony trioxide. To be

The method for molding a foam from the vinyl chloride resin composition of the present invention is not particularly limited, and for example, an extrusion molding method is preferably adopted. As the extrusion molding method, for example, a modified forming method using a pipe die, a selka foam molding method,
A grain-like foam molding method using a porous die may be used. Any extruder may be used as the extruder used in the extrusion molding method, and a single-screw extruder, a twin-screw extruder or the like is preferably used.

In the case of molding by an extruder, the molding temperature is
The linder temperature is the supply side temperature (hereinafter C ₁Is 80)
160 ° C, central temperature (hereinafter C₂Is said to be 100-1
80 ° C and discharge side temperature (hereinafter C₃Is called) 130-2
It is preferable to set each temperature to 00 ° C, and the mold temperature (below
The lower temperature D) is preferably 120 to 200 ° C.

[0022]

Embodiments of the present invention will be described below. (Examples 1 to 6, Comparative Examples 1 to 6) Predetermined amounts of vinyl chloride resin (a), urea compound (b) and thermal decomposition type inorganic foaming agent (c) shown in Tables 1 and 2 (Eiwa Chemical Industry Co., Ltd.) "Cerbon SC-D" manufactured by the company, tin stabilizer ("ONZ" manufactured by Sansha Machine Co., Ltd.)
-142F "), 5 parts by weight of acrylic processing aid (" Metablen P-530 "manufactured by Mitsubishi Rayon Co., Ltd.), 5 parts by weight of calcium carbonate (" CCR "manufactured by Shiraishi Calcium Co., Ltd.), polyethylene wax (Mitsui Petrochemical Co., Ltd.). Company "Hiw
ax4202E ") 1 part by weight, glycerin monostearate (" Rikemar S-100 "manufactured by Riken Vitamin Co., Ltd.) 1
Parts by weight and ester-based lubricant ("SL- manufactured by Riken Vitamin Co., Ltd.
02 ") 0.2 part by weight was supplied to a Henschel mixer and uniformly mixed to obtain a vinyl chloride resin composition.

The obtained vinyl chloride resin composition was applied to a single-screw extruder having the following specifications ("GT" manufactured by Plastic Engineering Laboratory Co., Ltd.).
-32-A ") and molded under the following molding conditions to obtain a vinyl chloride resin foam. [Extruder specifications] 1) Cylinder: diameter 300 mm 2) Screw: L / D = 28 3) Mold: T die, lip: width 150 x thickness 2 mm [Molding conditions] 1) Molding temperature: C ₁ = 150 ° C , C ₂ = 175 ° C., C ₃
= 180 ° C., D = 175 ° C. However, Example 6
And in Comparative Example 4, C ₁ = 150 ° C., C ₂ = 18
The temperature was set to 5 ° C., C ₃ = 190 ° C., and D = 185 ° C. 2) Screw rotation speed: 20 rpm

The vinyl chloride resin foams obtained in the above Examples and Comparative Examples were evaluated as follows, and the results are shown in Tables 1 and 2. (1) Expansion ratio The apparent density of vinyl chloride resin foam is ASTM D1.
The expansion ratio was calculated by the following formula. Expansion ratio (times) = 1.5 / apparent density

(2) Cell diameter Observing the cross section of the vinyl chloride resin foam with an optical microscope,
The average bubble diameter was measured.

(3) State of Foamed Cell At the same time as observing the bubble diameter, the state of the foamed cell was observed.
The evaluation was made according to the following criteria. ◯: The cells are uniformly dispersed, Δ: The cell dispersion state is slightly non-uniform, x: The cell dispersion state is non-uniform.

(4) Resin pressure The pressure sensor attached to the above single-screw extruder was attached to measure the resin pressure during extrusion molding.

(5) Load The current flowing through the motor that rotates the screw of the single-screw extruder was measured with the attached ammeter.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

EFFECT OF THE INVENTION The vinyl chloride resin composition of the present invention is as described above, can be easily molded without imposing an excessive load on a molding machine at the time of extrusion molding, and is uniform even at a high expansion ratio. Since the foamed molded product having a fine cell structure is provided, the foamed molded product can be suitably used for building materials such as deck materials, sizing materials, roofing materials, heat insulation applications, sound insulation applications, and the like.

Claims (1)

[Claims] 1. (a) 100 parts by weight of vinyl chloride resin,
(B) General formula R ¹ NHCONHR ² (wherein R ¹ , R ²
Represents an alkyl group having 1 to 23 carbon atoms or a phenyl group)
0.1 to 10 parts by weight of a urea compound represented by and (c)
A vinyl chloride resin composition comprising 0.2 to 5 parts by weight of a pyrolytic inorganic foaming agent.