JPH089183B2 - Method for producing a cord-shaped or reticulated foam reinforced with a core material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention mainly relates to cushioning binding materials, household products such as table cloths, and cords or nets reinforced with a core material suitable for use as an interior material. The present invention relates to a method for producing a foam.

(Prior Art) A cord-shaped or reticulated foam reinforced with a core material is usually formed by adhering or impregnating a heat-expandable composition of a vinyl chloride resin paste to a core material composed of a cord or a reticulated structure, and heating the composition. Obtained by foaming.

(Problems of the prior art) However, in the above conventional technology, a heat-foamable composition made of a vinyl chloride resin paste is heat-foamed, but in this method, a foaming ratio is usually 5 to 10 times and a higher foaming rate than this. There is a problem that a foam of a magnification cannot be obtained, and the vinyl chloride resin paste is a viscous liquid,
There is a problem that it is difficult to impregnate or attach the cord-like or net-like structure with a uniform thickness.

(Means for Solving Problems) The method for producing a cord-shaped or mesh foam reinforced with a core material according to the present invention is made to solve the above-mentioned problems, and has a cord-shaped or mesh structure. The object is achieved by adhering or impregnating a thermoplastic resin foamable composition pulverized to a fine particle size to a core material composed of a body, and then heat-foaming.

The thermoplastic resin used in the powdery thermoplastic resin foamable composition used in the present invention includes polyolefin resins such as polyethylene and polypropylene, ethylene-vinyl acetate copolymer resin, ethylene-acrylic ester copolymer resin. Ethylene copolymer resins such as ethylene-methacrylic acid ester copolymer resins, and vinyl chloride resins such as vinyl chloride resins and vinyl chloride-vinyl acetate copolymer resins are preferable.

The foamable composition is preferably one that forms an open cell, and is, for example, one or two of the above thermoplastic resins.
A foaming agent, a foaming aid, a cross-linking agent and, if necessary, a foam stabilizer and the like are blended in at least one kind. The powder is pulverized by crushing the pellets.

Examples of the foaming agent preferably used in the present invention include diazo type foaming agents such as azodicarbonamide, and examples of the foaming aid include metal salts of resin acids such as zinc stearate, zinc oxide and urea.

Further, as the cross-linking agent, a peroxide such as dicumyl peroxide is suitable, and the thermoplastic resin foamable composition causes a cross-linking reaction inside the thermoplastic resin when heated, thereby forming the foam. It has the function of preventing the foaming caused by the thermal decomposition of the agent from being destroyed.

On the other hand, as the foam stabilizer, for example, a silicone-based surfactant is suitable, and the foam stabilizer plays a role of uniformly controlling the size of bubbles during foaming.

The particle size of the powdery thermoplastic resin foamable composition suitable for the present invention is 10 to 1,000 μm, but in the core material described later, in order to obtain a uniform adhesion and a uniform foamed layer, it is desirable.
It is preferable to use one having a range of 50 to 500 μm.

If the particle diameter of the powder exceeds 1,000 μm, the adhesion of the powder to the core material becomes non-uniform, and the foam layer of the obtained string-like or reticulated foam also becomes non-uniform, impairing the commercial value. .

When the particle size of the powder is less than 10 μm, it becomes difficult to pulverize the powder, the crushing cost becomes high, and the foam layer of the obtained string-like or reticulated foam becomes thin and flat, resulting in a commercial value. Will be scarce.

The powder with a particle size of 200 μm or more is
Further, powder having a particle size of less than 200 μm can be obtained by a freeze pulverization method.

Examples of the core material of the present invention include plastic rods such as polyethylene and polypropylene, reticulated structures formed from the rods, natural fibers such as cotton and hemp, and reticulated structures formed from the natural fibers, synthetic fibers such as nylon and polyester, and the like. A reticulated structure made of synthetic fibers, a metal wire such as an iron wire, and a reticulated structure of the metal are preferably used.

In the present invention, in order to adhere or impregnate the core material with the foamable composition, for example, a rubber-based adhesive is applied to the surface of the core material, and then the powdery thermoplastic resin foamable composition is dipped. By applying it evenly to the surface of the core material,
The target product can be obtained by heating and foaming in an oven or the like.

When the core material is a metal string or a net-like structure, the core material heated to a temperature slightly higher than the melting point of the thermoplastic resin used is the powdery thermoplastic resin. After being immersed in the foamable composition and melted and adhered,
The target product can also be obtained by heating and foaming in an oven.

The expansion ratio of the cord-shaped or reticulated foam reinforced with the core material in the present invention is preferably in the range of 2 to 40 times, but preferably in the range of 5 to 20 times.

If the expansion ratio is less than 2 times, the flexibility of the foam,
This is because the cushioning property is likely to be lost, and when the expansion ratio exceeds 40 times, the mechanical strength of the foam tends to decrease.

(Operation) According to the present invention, the core material made of a string-like or net-like structure is impregnated with or adhered with the powdery thermoplastic resin foamable composition, and then heat-foamed to obtain the core material. Adheres to the thermoplastic resin foam and is firmly enclosed inside the foam.

(Examples) Examples of the present invention will be described below.

Example-1 Ethylene-vinyl acetate copolymer resin 100 parts by weight (vinyl acetate content 14%) Azodicarbonamide 8 parts by weight Dicumyl peroxide 1.5 parts by weight Urea 3 parts by weight Zinc oxide 2 parts by weight Silicon modified surfactant 2 Parts by weight The above composition was molded into pellets using a general-purpose single-screw extruder, and the pellets were pulverized by freeze pulverization to obtain a powdery thermoplastic resin foamable composition having an average particle size of 150 μm. Using a wire with a diameter of 1 mm heated to 130 ° C as the core material,
The core material is immersed in the powdery thermoplastic resin foamable composition to be evenly attached to the core material, and then heated in an oven at an ambient temperature of 190 ° C. for 2 minutes to decompose the foaming agent. By doing so, as shown in FIG. 1, a cord-shaped foam 2 having a wire as the cord-shaped core material 1 inside was obtained.

The obtained foam has an outer diameter of about 4 mm and a density of 0.07 g / c.
It was c (about 14 times foaming). Also, although the appearance is not smooth,
The thing with the beauty of nature was obtained.

Example-2 A polypropylene fiber net (fiber diameter 0.5 mm, pitch about 15 mm) was used as a core material, a rubber adhesive was thinly applied to the surface of the core material, and the core material was used as in Example-1. Immersed in a powdery thermoplastic resin foamable composition blended in
It is uniformly attached to the core material and heated for about 4 minutes in an oven having an ambient temperature of 160 ° C., and as shown in FIG. 2, a reticulated foam having a polypropylene fiber net as a reticulated core material 3 therein. I got body 4.

The resulting foam is thick (about 1.
5mm), thin in the straight part (about 0.7mm), its density is 0.06g / cc
(About 16 times foaming).

 A foam having a smooth appearance and a beautiful appearance was obtained.

Comparative Example-1 With the same composition as in Example-1, a wire having a diameter of 1 mm heated to 130 ° C was immersed in a powdery thermoplastic resin having an average particle size of 1,500 µm, and the same as in Example-1 By the heating method, a cord-shaped foam having a wire as a core material was obtained.

The surface of the obtained foam was very uneven, and the core material was partially exposed, and the product value was low.

(Effect of the Invention) According to the present invention, a means for adhering or impregnating a powdery thermoplastic resin foamable composition to a core material composed of a string-like or net-like structure and foaming by heating is adopted. It is easy to obtain a homogeneous foam that has both the cushioning properties and strength required for foams, and the core material can be freely selected from plastic, fiber, metal, etc. Not only a complicated mesh structure but also a foam reinforced by a core material having a three-dimensionally complicated mesh structure can be easily provided, and the application is expanded.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a cord-like foam reinforced with a core material obtained by the manufacturing method of the present invention, and FIG. 2 is an example of a reticulated foam reinforced with the core material of the present invention. It is a perspective view. 1 ... string-shaped core material, 2 ... string-shaped foam material 3 ... net-shaped core material, 4 ... net-shaped foam material

Claims (3)

[Claims] 1. A core material comprising a string-like or net-like structure,
A method for producing a cord-shaped or reticulated foam reinforced with a core material, which comprises adhering or impregnating a thermoplastic resin foamable composition crushed to a particle size of 10 to 1,000 μm, and then heat-foaming. 2. A means for adhering or impregnating a thermoplastic resin foamable composition to a core material, preliminarily impregnating the core material with an adhesive, or adhering an adhesive agent to the surface of the core material, followed by heat treatment. The method for producing a cord-shaped or reticulated foam reinforced with a core material according to claim 1, wherein the foamed composition of a plastic resin is impregnated in a bath. 3. A method for producing a cord-shaped or reticulated foam reinforced with a core material according to claim 1, wherein the expansion ratio is 2 to 40 times.