JPH093232A - Foaming polyvinyl chloride composition - Google Patents

Abstract

PURPOSE: To obtain a foaming polyvinyl chloride resin composition which comprises a polyvinyl chloride, an epoxy compound, calcium carbonate and a heat decomposable organic foaming agent at a specific proportion and has fine and uniform foam, excellent surface state, high adhesion of the resin to calcium carbonate. CONSTITUTION: The composition comprises (A) 100 pts.wt. of a polyvinylchloride resin, (B) 1-20 pts.wt. (per 100 pts. of (C)) of an epoxy compound such as epoxidized soy bean oil and (C) 5-50 pts. of calcium carbonate premixed with (B) and (D) 0.1-1.5 pts. of a heat decomposable compound such as azodicarbonamide.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a foamable vinyl chloride resin composition.

[0002]

2. Description of the Related Art Generally, vinyl chloride resin foams are widely used for interior materials of homes, furniture materials and the like because they are excellent in weather resistance, can be freely colored and have flame retardancy. In the case of extrusion molding of expandable vinyl chloride resin,
The bubbles generated by the decomposition of the foaming agent cause abnormal foaming,
It can be re-fused or destroyed, resulting in
There is a problem that voids, sink marks, shrinkage, etc. occur in the molded product, making it difficult to obtain a foam having a uniform cell diameter.

To obtain a vinyl chloride resin foam having a uniform cell diameter and a good surface condition, for example, Japanese Patent Publication No.
Japanese Unexamined Patent Publication No. 3-9540 discloses a foamable resin composition containing a methacrylic acid ester resin and calcium carbonate as a filler. However, when calcium carbonate is used in the expandable vinyl chloride resin composition, hydrogen chloride generated from the vinyl chloride resin during molding reacts with calcium carbonate to generate carbon dioxide, which makes the bubble diameter unstable. However, there is a problem that it is difficult to obtain a foam having a good fine cell structure and a surface condition.

Epoxy compounds are used as stabilizers for vinyl chloride resins, but there is no literature that they are used as a decomposition inhibitor for calcium carbonate.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks, and an object thereof is to provide a foamed product having a fine and uniform cell diameter and a good surface condition. It is to provide a vinyl chloride resin composition.

[0006]

The expandable vinyl chloride resin composition of the present invention comprises a vinyl chloride resin, calcium carbonate premixed with an epoxy compound, and a pyrolytic organic foaming agent.

As the vinyl chloride resin used in the present invention, a vinyl chloride homopolymer; a copolymer of vinyl chloride and a monomer having an unsaturated bond copolymerizable with the vinyl chloride; vinyl chloride grafted Examples of the graft copolymer include a chlorinated vinyl chloride resin obtained by post-chlorinating a vinyl chloride resin, and these may be used alone or in combination of two or more kinds.

The monomer having an unsaturated bond is not particularly limited, and examples thereof include ethylene and
Α-Olefins such as propylene and butylene; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as butyl vinyl ether and cetyl vinyl ether; acrylic acid esters such as methyl acrylate and ethyl acrylate; methyl methacrylate and ethyl methacrylate. Methacrylic acid esters such as phenyl methacrylate; aromatic vinyls such as styrene and α-methylstyrene; N-substituted maleimides such as N-phenylmaleimide and N-cyclohexylmaleimide, etc., and these are used alone. Or two or more may be used in combination.

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-butyl 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.

If the average degree of polymerization of the above vinyl chloride resin is small, the obtained molded article tends to shrink after foaming,
When it becomes large, the melt viscosity at the time of molding becomes high, and it becomes difficult to foam uniformly, so 600 to 1,000 is preferable.

In the present invention, calcium carbonate is premixed with an epoxy compound before use. By such premixing, the surface of the calcium carbonate powder can be coated with the epoxy compound, and by such coating, hydrogen chloride generated from the vinyl chloride resin at the time of molding reacts with calcium carbonate, It is possible to prevent carbon dioxide from being produced.

As the above-mentioned calcium carbonate, commercially available ones are generally used preferably, and the average particle size of 5 μm or less is preferable because the surface of the molded body becomes rough as the particle size of calcium carbonate increases.

The above-mentioned epoxy compounds include epoxidized animal and vegetable oils such as epoxidized soybean oil and epoxidized linseed oil;
Epoxidized fatty acid esters such as epoxidized fatty acid octyl ester and epoxidized fatty acid alkyl ester; epoxidized alicyclic compounds such as epoxidized tetrahydrophthalate, bisphenol A diglycidyl ether,
Examples thereof include epoxidized polybutadiene, and these may be used alone or in combination of two or more kinds.

The mixing ratio of the calcium carbonate and the epoxy compound is 1 to 20 parts by weight of the epoxy compound with respect to 100 parts by weight of calcium carbonate, since the amount of the epoxy compound causes bleeding out from the molded body.

In the expandable vinyl chloride resin composition of the present invention, when the amount of calcium carbonate is small, the uniformity of the cell diameter and the surface smoothness of the resulting molded article are low, and when it is high, the load during molding becomes large. In addition, since the mechanical strength of the molded product decreases, it is limited to 5 to 50 parts by weight with respect to 100 parts by weight of the vinyl chloride resin.

Examples of the thermal decomposition type organic foaming agent used in the present invention include azodicarbonamide, dinitrosopentamethylenetetramine, p, p'-oxybisbenzenesulfonylhydrazide, azobisisobutyronitrile and the like. However, azodicarbonamide is preferable from the viewpoint of handling.

In the above resin composition, when the amount of the pyrolyzable organic foaming agent is small, a molded product having a predetermined expansion ratio cannot be obtained, and when it is large, abnormal foaming cannot give a fine and uniform cell diameter, and chloride Since the vinyl resin has poor thermal stability, it is added in an amount of 0.1 to 100 parts by weight of the vinyl chloride resin.
Limited to 1.5 parts by weight.

If necessary, a heat stabilizer, a filler, a processing aid, a lubricant, etc. may be added to the above resin composition in order to improve the moldability and heat stability of the vinyl chloride resin. Good.

As the heat stabilizer, any of lead-based, tin-based and metal soap-based heat stabilizers can be used. Examples of the lead-based heat stabilizer include tribasic lead sulfate, tribasic lead sulfite, lead stearate, and dibasic lead stearate, which may be used alone or in combination of two or more. May be used in combination. Many of the above tin-based heat stabilizers inhibit the decomposition of azodicarbonamide, but dibutyltin malate can be used. As the metal soap-based heat stabilizer, a calcium-zinc-based composite stabilizer can be used, but if the heat-stabilizing effect is small, a large amount may be used.

Examples of the filler include talc, clay, mica, glass fiber, titanium oxide, alumina, wood powder and the like.

Examples of the processing aid include methylmethacrylate-ethylmethacrylate copolymer, high molecular weight polymethylmethacrylate and the like.

Further, a colorant, a flame retardant, an ultraviolet absorber, an antioxidant, an antistatic agent, etc. may be added to the above resin composition within the range of not impairing the mechanical strength of the molded product. Examples of the flame retardant include halogen-based flame retardants,
Examples thereof include phosphorus-based flame retardants and metal oxide-based flame retardants such as antimony trioxide.

As a method for producing the foamable vinyl chloride resin composition, calcium carbonate and an epoxy compound are mixed in advance with a super mixer, a Henschel mixer or the like, and then uniformly mixed with other components while heating with a Henschel mixer or the like. Examples thereof include a method of dispersing the mixture to form a mixture and a method of extruding the mixture from an extruder and then cutting the mixture with a pelletizer to form pellets, but a method of pelletizing is more preferable.

[0024]

EXAMPLES Examples will be shown below, but the present invention is not limited thereto. Preliminary Mixing of Calcium Carbonate and Epoxy Compound Predetermined amounts of calcium carbonate and epoxy compound shown in Table 1 were put into a super mixer (Kawata Industry Co., Ltd., capacity 100 liters) and mixed at 90 ° C. for 30 minutes to perform preliminary mixing. . In addition, as calcium carbonate, “CC manufactured by Shiraishi Industry Co., Ltd.
R ”was used.

[0025]

[Table 1]

(Examples 1 to 8 and Comparative Examples 1 to 9) Vinyl chloride resin ("TS-800E" manufactured by Tokuyama Sekisui Industry Co., Ltd.) 100
Parts by weight, tribasic lead sulfate ("TL-700" manufactured by Sakai Chemical Industry Co., Ltd.
0 ") 2.5 parts by weight, methacrylic acid ester resin (" P-530A "manufactured by Mitsubishi Rayon Co., Ltd.) 5 parts by weight, and azodicarbonamide (" Vinihol AC # 1 "manufactured by Eiwa Chemical Co., Ltd.).
To 108 parts by weight of the basic formulation consisting of 0.5 parts by weight, Table 2
Calcium carbonate premixed with a predetermined amount of the epoxy compound shown in was added, and the mixture was heated and mixed by a super mixer until the temperature reached 105 ° C. This mixture is then 50 mm
Extrusion molding was carried out using a biaxial different-direction extruder to obtain pellets as a foamable vinyl chloride resin composition.

[0027]

[Table 2]

The following items were evaluated for the above pellets and the flat-plate foam molded article molded from the pellets, and the results are shown in Table 3. (1) Gas composition analysis The pellets were heated in a gear oven at 160 ° C for 5 minutes to collect the generated gas, which was analyzed by a gas chromatograph.
The gas composition of nitrogen, carbon monoxide and carbon dioxide was analyzed.

(2) Surface condition Using the 50 mm biaxial different direction extruder, the above pellets were
Extrusion molding under the following extrusion conditions, 10mm x 70mm
After obtaining the flat foam molded article, the surface smoothness and bleeding property of the obtained molded article were visually observed and evaluated according to the following criteria. (Extrusion conditions) Barrel temperature: From mold side 166 ° C, 155 ° C, 155 ° C
Set to. Mold temperature was set to 155 ° C. Screw rotation speed: 18 rpm, feeder rotation speed: 8
rpm [Evaluation criteria for surface smoothness] ○: Surface is smooth without waviness △: Surface is not smooth ×: Surface is not smooth and waviness is observed [Evaluation criteria for bleeding property] ○: Touch with finger There is no sticky feeling when you touch it, and it is smooth. ×: There is a sticky feeling when you touch it with your finger.

(3) Uniformity of Cell Diameter After the flat-plate foamed molded product was cut along a plane perpendicular to the extrusion direction, this cross section was observed under a microscope of 100 times to obtain the center and the surface layer of the molded product. The bubble diameter of each part was observed, and the uniformity of the bubble diameter was evaluated according to the following criteria. ◯: The bubble diameter in the central portion was uniform ×: The bubble diameter in the central portion was uneven

(4) Specific gravity The specific gravity of the flat foam molding was measured according to JIS K7112.

[0032]

[Table 3]

In Comparative Examples 1 to 3, bleeding occurred because the surface smoothness was poor and the amount of epoxy compound added was large. Further, in Comparative Examples 1, 6 and 7, since the amount of carbon dioxide generated was large, the uniformity of the bubble diameter was poor and continuous bubbles and voids were generated.

[0034]

EFFECT OF THE INVENTION The expandable vinyl chloride resin composition of the present invention has the above-mentioned constitution, and by premixing calcium carbonate and an epoxy compound, hydrogen chloride generated from the vinyl chloride resin during molding. Since carbon dioxide is prevented from being generated by the reaction between the resin and calcium carbonate, the adhesiveness between the resin and calcium carbonate is improved, and a foamed molded product having a fine and uniform cell diameter and a good surface condition can be obtained.

Claims (1)

[Claims] 1. A foamable vinyl chloride resin comprising 100 parts by weight of a vinyl chloride resin, 5 to 50 parts by weight of calcium carbonate premixed with an epoxy compound, and 0.1 to 1.5 parts by weight of a pyrolytic organic blowing agent. A resin composition, wherein the pre-mixing ratio of calcium carbonate and epoxy compound is 1 to 20 parts by weight of epoxy compound to 100 parts by weight of calcium carbonate, and a foamable vinyl chloride resin composition.