JPH0236142B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a polyvinyl chloride resin foam that prevents coloration during foaming. Vinyl chloride resin is used for flooring, wall materials, ceiling covering materials, and leather, which are manufactured by mixing or kneading a thermally decomposable organic foaming agent and a foaming aid called KITSUKA, which lowers the decomposition temperature of the foaming agent, and then heating and foaming the mixture. It is used in large quantities for such purposes. These flooring materials undergo printing, chemical embossing, and surface treatment during the manufacturing process. As seen in Japanese Patent Publication No. 43-15713 or Japanese Patent Publication No. 46-42637 as a solvent for printing inks used in printing and chemical embossing and chemicals used in chemical embossing,
Ketone compounds are preferably used because they have many advantages such as coating stability, suitability for coating with vinyl chloride resin, and ability to dissolve as a solvent. but,
For expandable vinyl chloride resin containing a blowing agent and a foaming aid, the surface of the molded product turns reddish-yellow after heating and foaming due to the ketone compound used as a solvent in the ink etc. applied to the surface before the heating and foaming process. This phenomenon occurred, which had the disadvantage of significantly reducing the product value. As a countermeasure to this problem, measures have been taken such as not using ketone compounds as a solvent or extremely reducing the proportion of their use, but no solvent has been found that can cover the above-mentioned performance of ketone compounds. The mainstream is to use ketone compounds as solvents. The inventor of the present invention conducted extensive research on a method that can prevent discoloration of the surface of molded products during foam molding even when using a coating agent using a ketone compound as a solvent, and found that a specific phosphite compound was used in combination with an organic blowing agent. They discovered that discoloration can be prevented by doing so, and have completed the present invention. That is, an object of the present invention is to provide a method for producing a vinyl chloride resin foam that prevents discoloration caused by a ketone compound of a pyrolyzable organic blowing agent. Therefore, the gist of the present invention is to obtain a foamable vinyl chloride resin composition containing a vinyl chloride resin, a thermally decomposable organic blowing agent, a powdered or solid zinc compound, and a phosphite compound as main components, and to decompose the blowing agent. The present invention relates to a method for producing a foam, which method comprises forming a film or sheet at a temperature that does not exceed 100 degrees, applying a coating agent containing a ketone compound as a solvent to the film or sheet, and then heating and foaming the film or sheet. The present invention will be explained in detail. The vinyl chloride resin used in the expandable vinyl chloride resin composition used in the method of the present invention can be prepared by a suspension polymerization method, a bulk polymerization method, a fine suspension polymerization method, or a mixture of vinyl chloride or vinyl chloride and a comonomer copolymerizable therewith. Any material produced by a conventional method such as a polymerization method or an emulsion polymerization method can be used. Therefore, examples of comonomers that can be copolymerized with vinyl chloride include vinyl esters such as vinyl acetate, vinyl propionate, and vinyl laurate, acrylic esters such as methyl acrylate, ethyl acrylate, and butyl acrylate, methyl methacrylate, and ethyl acrylate. Methacrylic acid esters such as methacrylate, maleic acid esters such as dibutyl maleate and diethyl maleate, fumaric acid esters such as dibutyl fumarate and diethyl fumarate, vinyl ethers such as vinyl methyl ether, vinyl butyl ether, and vinyl octyl ether. , vinyl cyanides such as acrylonitrile and methacrylonitrile, α-olefins such as ethylene, propylene and styrene, vinylidene halides other than vinyl chloride or vinyl halides such as vinylidene chloride and vinyl bromide. The comonomer is used in an amount of 30% by weight or less, preferably 20% by weight or less in the constituent components of the vinyl chloride resin. Of course, the comonomers are not limited to those mentioned above. Examples of the thermally decomposable organic blowing agent that is a component of the foamable vinyl chloride resin composition include dinitrosopentamethylenetetramine, azodicarbonamide, barium azodicarboxylate, azobisisobutyronitrile, P,P'-oxy Examples include bisbenzenesulfonyl hydrazide, para-toluenesulfonyl hydrazide, benzenesulfonyl hydrazide, etc., and azodicarbonamide or a similar structure thereof is particularly useful. And the amount used is
It is used in an amount of 0.5 to 30 parts by weight per 100 parts by weight of vinyl chloride resin. Any compound commonly referred to as a blower, which acts to lower the decomposition temperature of the blowing agent, is used as a blowing aid in the composition. As these compounds, zinc compounds are preferable from the viewpoints of safety and hygiene and processability, and for example, zinc oxide, zinc caprylate, zinc nitrate, zinc fatty acid soap, etc. are used.
Also, as a zinc compound, it is not a liquid,
It is preferable to use a powder or solid form; for example, even if fatty acid zinc is used, a liquid form such as zinc octylate cannot sufficiently exhibit the effect of preventing discoloration. The proportion of the blowing aid to be used is usually selected from the range of 1 to 10 parts by weight, particularly 1 to 5 parts by weight, per 100 parts by weight of the vinyl chloride resin, although it is related to the type and amount of the blowing agent. be done. A phosphite compound, which is an essential component of a foamable vinyl chloride resin composition, can effectively prevent or improve discoloration on the surface of a molded article, regardless of what is used as the foaming aid. The degree of prevention is
It varies depending on the type of foaming aid or phosphite compound used. Particularly effective in the method of the present invention are triphenyl phosphite, trisnonylphenyl phosphite, tridecyl phosphite, diphenyl mono(tridecyl) phosphite, tetraphenyl dipropylene glycol phosphite, and derivatives thereof. Furthermore, when used in combination with a powdered or solid zinc compound, an extremely good discoloration prevention effect is exhibited. However, the amount of phosphite compound added is
Usually in the range of 0.1 to 5 parts by weight per 100 parts by weight, especially
A range of 1.5 to 2.5 parts by weight is preferred. In addition to the above-mentioned essential components, the expandable vinyl chloride resin composition contains additives normally used in vinyl chloride resins, such as plasticizers, stabilizers, antioxidants, ultraviolet absorbers, fillers, colorants, and additives. Molding agents etc. are often used together. Plasticizers include, for example, di-n-butyl phthalate, di-n-octyl phthalate, di-2-ethylhexyl phthalate, diisooctyl phthalate, octyldecyl phthalate, diisodecyl phthalate, butylbenzyl phthalate, and diisophthalate. Phthalic acid plasticizers such as -2-ethylhexyl or phthalate esters of higher alcohols having about 11 to 13 carbon atoms, n-octyl-n-decyl trimellistate,
Trimellitic acid plasticizers such as tri-2-ethylhexyl trimellitate, triisodecyl trimellitate, and tri-n-octyl trimellitate; di-2-ethylhexyl adipate; di-n-decyl adipate; diisodecyl adipate; Fatty acid ester plasticizers such as -2-ethylhexyl, dibutyl sebacate, di-2-ethylhexyl sebacate, tributyl phosphate, tri-2-ethylhexyl phosphate, 2-ethylhexyldiphenyl phosphate, tricresyl phosphate, etc. Phosphate ester plasticizer, epoxidized soybean oil, epoxidized linseed oil, epoxidized tall oil fatty acid
Examples include epoxy plasticizers such as 2-ethylhexyl, liquid epoxy resins, etc., and these may be used alone or in combination of two or more. The amount of plasticizer to be used is appropriately selected depending on the moldability, processability, workability of the composition, the purpose of the molded product, etc., but it is generally 30 to 400 parts by weight per 100 parts by weight of the vinyl chloride resin. parts, preferably 50-200
Parts by weight range. If the foamable vinyl chloride resin composition is a sol composition, a part of the plasticizer may be replaced with a diluent such as texanol isobutyrate, dodecylbenzene, or kerosene, or a vinyl chloride resin such as toluene or xylene. It can be replaced with an organic solvent that causes swelling, and may be used in the form of an organosol. The amount of diluent and organic solvent added is
It is determined as appropriate depending on the purpose. Rather than using tin-based stabilizers such as tin fatty acid salts and tin mercaptide, stabilizers based on barium-zinc (Ba-Zn), calcium-zinc (Ca-Zn), etc.
It is easier to use a non-tin based metal stabilizer such as magnesium-zinc (Mg-Zn) to exhibit the effect of the organic blowing agent as a foaming aid. Furthermore, many stabilizers generally have the properties of foaming aids.
The amount of stabilizer used is preferably in the range of 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight, per 100 parts by weight of the vinyl chloride resin. The foamable vinyl chloride resin composition is made by adding a vinyl chloride resin, a pyrolytic blowing agent, a blowing aid, a phosphite compound, and other additives as necessary, and mixing them uniformly. Manufactured. If the composition uses a vinyl chloride resin manufactured by suspension polymerization or bulk polymerization, it is hot-dry blended using a high-speed stirrer, etc., then uniformly stirred with a Banbury mixer, and then mixed with a calender roll or the like. It is then molded into a film or sheet within a temperature range where the blowing agent does not decompose. On the other hand, in the case of a composition using a vinyl chloride resin manufactured by an emulsion polymerization method or a fine suspension polymerization method, the above-mentioned components are uniformly dispersed in a sol form,
It is coated onto a non-releasable or releasable base material by a method such as knife coating, and heated to a temperature at which the foaming agent does not decompose to form a gelatinous film or sheet. The method of the present invention uses alicyclic ketones such as cyclohexanone, methyl ethyl ketone, etc. After applying printing ink, chemical embossing printing ink, surface treatment agent, paint, etc. using group saturated ketones, unsaturated ketones, aromatic ketones, or heterocyclic ketones as a solvent, heating to a temperature higher than the temperature at which the blowing agent decomposes. and foaming to produce a foam. The foam is used as flooring materials, wall materials, ceiling materials, automobile interior materials, and other decorative materials. In the method of the present invention, the foamable vinyl chloride resin composition does not turn red or yellow even when it comes into contact with a ketone compound during heating and foaming, and it is possible to obtain a more beautiful molded product compared to conventional foam molded products. This is of great industrial advantage. Next, the method of the present invention will be explained in detail with reference to Examples, but the method of the present invention is not limited to the following Examples unless the gist of the method is exceeded. Example 100 parts by weight of polyvinyl chloride paste resin with an average degree of polymerization of 900, dioctyl phthalate (DOP) 60
Parts by weight, 10 parts by weight of mineral spirits, 30 parts by weight of calcium carbonate (filler), 15 parts by weight of aluminum hydroxide (flame retardant), 5 parts by weight of titanium oxide (white pigment)
parts by weight, 5 parts by weight of azodicarbonamide and the first
An organosol consisting of tridecyl phosphite or a blowing aid in the amount shown in the table was prepared and coated on paper using a knife coater, and then gently gelled at 130°C for 60 seconds to obtain a sheet with a thickness of 0.15 mm. . Transparent inks having the following compositions A and B were applied as patterns on a part of the surface of the sheet. (A) Paste resin 5 parts by weight Cyclohexanone 100 parts by weight (B) Paste resin 5 parts by weight Methyl ethyl ketone 100 parts by weight This ink was dried and then heated and foamed at 220°C for 65 seconds to obtain a wallpaper-like foam molded product. The degree of change to reddish-yellow was visually evaluated on a 5-grade scale of 1 to 5. The results were the same for both transparent ink compositions (A) and (B), as shown in Table 1.

【table】

[Table] As is clear from the examples, the product to which dodecyl phosphite was added was improved by two ranks over the foaming aid alone, and the use of a powdered zinc-based foaming aid in combination showed particularly good results. ing.

Claims (1)

[Scope of Claims] 1. Temperature at which the blowing agent does not decompose from a foamable vinyl chloride resin composition containing a vinyl chloride resin, a thermally decomposable organic blowing agent, a powdered or solid zinc compound, and a phosphite compound as main components. 1. A method for producing a foam, which comprises forming a film or sheet using the foam, applying a coating agent containing a ketone compound as a solvent to the film or sheet, and then heating and foaming the film or sheet. 2. The method for producing a foam according to claim 1, wherein the pyrolyzable organic blowing agent is azodicarbonamide. 3. The method for producing a foam according to claim 1 or 2, wherein the amount of the pyrolyzable organic blowing agent used is in the range of 0.3 to 30 parts by weight per 100 parts by weight of the vinyl chloride resin. 4. Claim 1, wherein the phosphite compound is at least one of triphenyl phosphite, trisnonylphenyl phosphite, tridecyl phosphite, diphenyl mono(tridecyl) phosphite, tetraphenyl dipropylene glycol phosphite, etc. The method for producing a foam according to item 2 or 3. 5. Claims 1, 2, 3, or 4, wherein the amount of the phosphite compound added is in the range of 0.1 to 5 parts by weight per 100 parts by weight of vinyl chloride resin.
2. Method for producing the foam described in Section 1.