JPS5846248B2 - Vinyl chloride resin foam composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vinyl chloride resin foam composition, and more specifically, a powder resin obtained by spray-drying an aqueous vinyl acetate resin emulsion to 100 parts by weight of a vinyl chloride resin.
This relates to a vinyl chloride resin foam composition prepared by adding an appropriate amount of a blowing agent to 5 to 40 parts by weight and 30 to 110 parts by weight of a liquid plasticizer.

Compared to other foams, such as rubber foams, vinyl chloride resin foams are non-flammable, are generally flexible, and are resistant to aging, friction, water resistance, tearing, etc. It also does not oxidize, dry or harden.

Moreover, it has a high degree of elasticity, is odorless, and can be colored in any color.

Such a vinyl chloride resin foam is produced by heating a composition prepared by blending a vinyl chloride resin with a liquid plasticizer and a foaming agent to a high temperature to melt it and foam it.

However, with conventional vinyl chloride resins, it has been difficult to obtain uniform foams with excellent appearance and feel.

In other words, a vinyl chloride resin composition containing a liquid plasticizer and a blowing agent has a remarkable change in melt viscosity depending on the melting temperature.
The melt viscosity changes significantly even with a slight temperature difference during heating, melting, and foaming, and it has been difficult to achieve uniform foaming because the foaming conditions are not constant.

In order to obtain a uniform foam, it is necessary to select a blowing agent and adjust the melting temperature, but it is necessary to select a blowing agent that foams at a temperature that exhibits an appropriate melt viscosity and that foams sufficiently within a narrow temperature range. It has been difficult to precisely adjust the melting temperature of vinyl chloride resin compositions within a narrow melting temperature range.

For this purpose, as a means to keep the foaming conditions constant,
Butadiene/acryloni l- is added to the vinyl chloride resin composition.
A method of blending an IJ copolymer or an ethylene/vinyl acetate copolymer resin has been proposed.

This method suppresses viscosity changes due to temperature changes in the melt by blending a butadiene/acrylonitrile copolymer or ethylene/vinyl acetate copolymer resin into a vinyl chloride resin composition, thereby maintaining the desired viscosity over a wide temperature range. It maintains the foaming conditions and stabilizes the foaming conditions to produce a uniform vinyl chloride resin foam.

However, this method has the disadvantage that the foaming speed is slow.

The present inventor investigated various synthetic resins in order to obtain a polyvinyl chloride resin foaming composition that has a high foaming speed and can be foamed uniformly.As a result, the present inventor developed a powder resin obtained by spray-drying an aqueous vinyl acetate resin emulsion. It has been found that by adding it to a vinyl chloride resin foam composition, the foaming speed is high and the foaming is uniform.

The present invention is a vinyl chloride resin made by adding an appropriate amount of a blowing agent to 100 parts by weight of a vinyl chloride resin, 0.5 to 40 parts by weight of a powder resin obtained by spray-drying an aqueous emulsion of a vinyl acetate resin, and 30 to 110 parts by weight of a liquid plasticizer. It is a resin foam composition.

The vinyl chloride resin foam composition of the present invention is characterized by the combined use of a powdered resin obtained by spray-drying an aqueous vinyl acetate resin emulsion.

Vinyl acetate resin aqueous emulsions are obtained by emulsion polymerization of vinyl acetate monomers, but resins obtained by emulsion polymerization can be obtained by other solution polymerization, bulk polymerization, suspension polymerization, etc. It has the characteristic that a resin having a higher molecular weight (higher degree of polymerization) than the resulting resin can be obtained.

In addition, resin powder obtained by spray-drying an aqueous emulsion is made by force-drying fine resin particles that have been adjusted to be stably dispersed in water. It is characterized by very good dispersibility compared to resin powder obtained by pulverization.

Theoretically, it is not necessarily clear why the foaming state of a foamed vinyl chloride resin composition improves when a powdered resin obtained by spray-drying an aqueous vinyl acetate resin emulsion is blended.

However, when the composition is melted, it has almost the same effect as the above-mentioned butadiene-acrylonitrile copolymer in suppressing viscosity changes due to temperature changes, but powdered resin made by spray-drying an aqueous vinyl acetate resin emulsion The blended polyvinyl chloride resin foam composition has a unique effect that is different from other polymers in that its foaming speed is extremely fast.

Such an effect is not seen in other polymers, and even in vinyl acetate resin powder, it is a special effect that cannot be seen in powdered resins other than emulsion polymerized resins.

The powder resin obtained by spray-drying the aqueous vinyl acetate resin emulsion used in the present invention is obtained by first emulsion polymerizing the vinyl acetate monomer in water using a known method using an emulsifier, a polymerization catalyst, etc. An emulsion is obtained, appropriate additives are added to the obtained aqueous vinyl acetate resin emulsion, and the mixture is spray-dried using a spray dryer.

The vinyl acetate monomer is a monomer consisting of 30 to 100 parts by weight of vinyl acetate and 0 to 70 parts by weight of a monomer copolymerizable with vinyl acetate.

Monomers copolymerizable with vinyl acetate include vinyl esters other than vinyl acetate (for example, vinyl propionate and Beoba (trade name of Shell Chemical Co.), etc.), acrylates,
These include nucleates, unsaturated carboxylic acids (eg, crotonic acid, acrylic acid, methacrylic acid, 71-ynoic acid, iconic acid, etc.), ethylene, styrene, vinyl chloride, acrylonitrile, and the like.

70% by weight of these monomers copolymerizable with vinyl acetate
If it is more than that, the compatibility with the vinyl chloride resin becomes poor, which is not preferable.

The amount of the powdered resin used is 0.5 to 40 parts by weight per 100 parts by weight of the vinyl chloride resin.

If it is less than 0.5 parts by weight, it will be difficult to achieve uniform foaming, and if it exceeds 40 parts by weight, it will have an adverse effect on the elasticity of the resulting vinyl chloride resin foam, which is not preferred.

As the liquid plasticizer used in the present invention, any liquid plasticizer that has already been used for vinyl chloride resins can be used.

For example, dioctyl phthalate, dibutyl phthalate,
dibutyl lauryl phthalate, dioctyl phthalate,
Phthalate ester plasticizers such as diisodecyl phthalate, indecyl phthalate, dilauryl tucrate, phthylbenzyl fucrate, and dimethyl glycol phthalate; aliphatic dibasic acid esters such as dioctyl adipate, dioctyl azelate, and dioctyl sebacate The plasticizer is one or more liquid plasticizers such as phosphate ester plasticizers such as tricresyl phosphate, polyester plasticizers, and epoxy plasticizers.

The amount of liquid plasticizer used is 30 to 110 parts by weight per 100 parts by weight of vinyl chloride resin.

If the amount of liquid plasticizer used is less than 30 parts by weight, a foam with high flexibility and elasticity cannot be obtained.

Moreover, if it exceeds 110 parts by weight, only a brittle foam will be obtained, which is not preferable.

Examples of the blowing agent used in the present invention include azodicarbonamide, dinitrosopencumethylenetetramine, benzenesulfonyl hydrazide, oxybisbenzenesulfonylhydrazide, diphenylsulfone-3,3'-
Organics such as disulfonyl hydrazide, toluenesulfonyl hydrazide, sodium bicarbonate, calcium azide,
Inorganic blowing agent or inert gas such as carbon dioxide or nitrogen,
Any low boiling point solvent can be used.

The amount of the blowing agent used is appropriately adjusted depending on the type of blowing agent, the use of the foam, and the required expansion ratio.

The vinyl chloride resin foam composition of the present invention includes a vinyl chloride resin, a powder resin obtained by spray-drying the above-mentioned vinyl acetate-based resin aqueous emulsion, and 100 parts by weight of the above-mentioned liquid plasticizer: 0.5 to 40 parts by weight. : 30 to 110 parts by weight, and a small amount of foaming agent is added thereto.

The vinyl chloride resin foam composition may further contain foaming aids such as salicylic acid, fucuric acid, benzoic acid, and urea derivatives, higher fatty acids such as cadmium, calcium,
Additives such as heavy metal salts such as barium, zinc, tin, and lead, stabilizers such as organic tin metal salts, fillers, colorants, and lubricants.
A species or two or more species can also be added.

As a method for mixing the foamed vinyl chloride resin composition of the present invention, it is preferable to mix using a mixer such as a mixing roll, a Banbury mixer, a calender roll, or an extruder.

Foaming methods for the vinyl chloride resin foam composition of the present invention include conventionally known methods for producing vinyl chloride resin foams, such as a calendar sheet normal pressure foaming method, a pressure foaming method, a paste resin foaming method, and a two-stage foaming method. Any foaming force method used in the method can be effectively employed.

The vinyl chloride resin foam composition of the present invention has a fast foaming speed and foams uniformly, so it can be used for a wide range of applications such as molding leather, foam, and various sponges. Since the bubbles are fine, homogeneous, and evenly dispersed, the elasticity, flexibility, feel, and appearance are all good.

Hereinafter, the present invention will be explained with reference to production examples and examples, but it is not limited thereto.

Production Example 1 The solid concentration of a vinyl acetate resin aqueous emulsion was adjusted to 35% by weight, introduced into a centrifugal spray dryer, and spray-dried under conditions of a hot air inlet temperature of 80°C and an exhaust air temperature of 50°C, A powdered resin was obtained.

Production Examples 2 to 5 Instead of the vinyl acetate resin aqueous emulsion used in Production Example 1, 0 vinyl acetate (95% by weight)/crotonic acid (5% by weight)
) Copolymer resin aqueous emulsion 0 Vinyl acetate (85% by weight)/Ethylene (15% by weight
) Copolymer resin aqueous emulsion O Vinyl acetate (75% by weight)/Beoba (trade name of Shell Chemical Co., Ltd., 25% by weight) Copolymer resin aqueous emulsion O Vinyl acetate (40% by weight)/Ethylene (15% by weight)
- A powdered resin was obtained in the same manner as in Production Example 1, except that a vinyl chloride (45% by weight) copolymer resin aqueous emulsion was used.

Example 1 100 parts by weight of vinyl chloride resin, 5 parts by weight of powdered resin obtained by spray-drying the vinyl acetate resin aqueous emulsion obtained in Production Example 1, 70 parts by weight of dioctyl phthalate (DOP), 30 parts by weight of inorganic filler, azodicarbonamide (Foaming agent) 5
parts by weight, 10 parts by weight of chlorinated paraffin, and 3 parts by weight of zinc-based stabilizer were uniformly mixed to obtain a vinyl chloride-based resin foam composition.

Examples 2 to 5 In the same manner as in Example 1, the compositions shown in Table 1 were uniformly mixed to obtain vinyl chloride resin foam compositions.

Comparative Example 1 Powdered resin 10 obtained in Production Example 3 used in Example 3
Instead of parts by weight, 60 parts by weight of vinyl acetate, 4 parts by weight of ethylene
A composition was obtained in the same manner as in Example 3, except that 10 parts by weight of powder obtained by mechanically pulverizing a resin lump consisting of 0 parts by weight was used.

Comparative Example 2 Powdered resin 10 obtained in Production Example 3 used in Example 3
A composition was obtained in the same manner as in Example 3, except that 10 parts by weight of commercially available polyvinyl alcohol powder was used instead of parts by weight.

Test Examples The foamed vinyl chloride resin compositions of Examples 1 to 5 and the compositions of Comparative Examples 1 to 2 were extruded onto paper using an extruder and heated at 160° C. for 60 seconds to pregelify them.

The obtained sheet was heated and foamed at 200° C. for 60 seconds, and the magnification after foaming was measured and the surface condition and sheet cross-sectional condition were observed.

The test results are shown in Table 2.

Claims (1)

[Claims] 1. 100 parts by weight of vinyl chloride resin, 0.5 to 40 parts by weight of powdered resin obtained by spray-drying an aqueous emulsion of vinyl acetate resin, and 30 to 110 parts by weight of liquid plasticizer, with an appropriate amount of blowing agent added. PVC resin foam composition.