JPS5962118A - Preparation of flexible foam material - Google Patents

Abstract

PURPOSE:To manufacture highly flexible foam material useful for clothings and sporting goods, etc. simply and economically at a high productivity by such an arrangement wherein more than 2 kinds of oelfine family resin of which elongation and tensile strength differ from each other are mixed and melted and caused to foam and after that said material is elongated. CONSTITUTION:More than 2 kinds of olefine family resin (polymer of olefine family monomer or copolymer primarily composed of monomers) of which elongation or/and tensile strength differ from other preferably by more than 20%, more preferably by more than 50% are mixed (preferably, 10-90wt% of one kind of olefine family resin are included) melted and caused to foam (preferably by a method whereby olefine family resin is bridged) and the material thus obtained is elongated preferably by more than 1.5 times by pinch rolls, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a flexible foam from an olefinic TY+fat foam.

Closed-cell olefin resin foam has thermal and sound insulation properties,
Although it is used for various purposes due to its excellent cushioning properties, it generally lacks flexibility, water absorption, breathability, and fit required for clothing, etc., so it is used for applications that require the above performance G' I couldn't use it at all.

Conventional method of converting closed cell foam into open cell)j,
, Mechanical processing methods such as punching a large number of holes with a needle punch, Boiling to enlarge the bubbles and stretching the cell membrane, Compressing after cooling to a temperature below the glass transition temperature of the resin. Various physical processing methods have been proposed, but they all require large equipment such as punching equipment, boiling equipment, cooling equipment, etc., which increases costs and has disadvantages such as poor productivity. There was nothing I was satisfied with.

The purpose of Zero Hatsuri J is to eliminate the above-mentioned drawbacks, have simple equipment,
Φ of economical flexible foam with high productivity of open cell formation
1. ! The goal is to provide a way to send money.

That is, the gist of the present invention resides in a method for producing a flexible foam, characterized by mixing and melting at least two types of olefin resins having different elongation and tensile strength, foaming, and then stretching.

Olefin system used in Suekan 1111 1
Polymers and copolymers of F4 olefins such as fat, ethylene, propylene, butylene, ethylene-vinyl acetate copolymers, ethylene-ethyl acrylate co-IR
It refers to a copolymer mainly composed of an olefin-based lit polymer such as a copolymer or an ethylene-vinyl chloride copolymer.

Zero shot 1! l], among the above olefin resins,
At least two types with different elongation and tensile strength (tensile strength) are used. The above two types may be a combination of polymers made of the same monomers as long as they have different elongation and tensile strength, such as a combination of different grades of low density polyethylene.

In short, it is a combination of at least two olefins 4↓lIll''V having different elongation and tensile strength, and any combination may be used as long as a foam is formed.
For example, in addition to the above, low density polyethylene and linear low density polyethylene, low density polyethylene and high density polyethylene,
low-density polyethylene and ethylene-vinyl acetate copolymer,
Combinations of high-density polyethylene and polypropylene, and polypropylene and propylene-ethylene copolymer Sasakaki are possible. Of course, three or more of the above olefin resins may be mixed. The degree of difference in elongation and tensile strength may be such that when the foam is stretched, the layers of the resin will shift, and it is preferable that at least one of elongation and tensile strength differs by 20% or more. It is more preferable that the two differ by 20% or more, and it is particularly preferable that the two differ by 50% or more. The mixing ratio of at least two types of olefin resins is 10 to 9.
Preferably, the content is 0% by weight. If the mixing ratio of the second and subsequent A fin resins is too small, the flexibility may not be satisfactory even when the foam is stretched.
At least two types of olefin resins having different elongation and tensile strength are mixed and melted to form a foam on a foam. olefin resin f
A method similar to the manufacturing technique for single-unit bodies can be used. For example, a pyrolytic foaming agent such as azodicarbonamide is mixed with a mixing ladle of olefin resin, and the mixture is fed into an extruder and extruded (the foaming agent is decomposed in a shallow chamber to form foamable resin #1).
Discharge the product from the nozzle of a T-guid, etc.ffl1
A physical blowing agent such as a low-boiling point aliphatic hydrocarbon or halogenated hydrocarbon is press-injected into the middle of the extruder, or the above-mentioned physical blowing agent is injected into the extrusion +Q and pre-impregnated with 1jq of resin mixture. A method of making a foamable resin composition by allowing the foam to flow and discharging it from a mouthpiece, or if
No. 7 Olefin type (61 fat mixture) is mixed with hot/j? type foaming tension, and after extrusion, cross-melting is carried out under pressure to the extent that the above foaming agent is not substantially decomposed using a render roll or the like from t. A method of obtaining a crosslinked foam by forming it into a sheet, crosslinking it by irradiating the sheet-like molded body with ionizing radiation, and then heating it to the decomposition temperature range of the blowing agent. A thermally decomposable blowing agent and a crosslinking agent are mixed into the reflex resin mixture marked R+1, and this is cross-melted using an extruder or a render roll etc. under pressure to the extent that the blowing agent and crosslinking agent are not substantially decomposed. Examples of the method include forming a sheet into a sheet, heating it to a temperature at which the crosslinking agent decomposes, crosslinking it, and then heating it to a temperature higher than the decomposition temperature of the blowing agent to obtain a crosslinked foam. Among the manufacturing methods, the method of crosslinking the olefin resin is particularly preferred because the viscosity of the molten resin can be adjusted and a foam having uniform, fine closed cells can be produced.

In addition, in manufacturing the foam, the above-mentioned tree, a foaming agent,
In addition to the crosslinking agent, it is of course possible to mix commonly used additives and auxiliaries such as stabilizers, ultraviolet light absorbers, lubricants, pigments, antistatic agents, fillers, and reinforcing agents. Furthermore, it is also possible to add resins such as polystyrene, acrylic resin, ABSIR resin, polygetadiene, and rubber.

In order to complete 1 liter of foam, 61 L of the foam obtained by the above method is sufficient. As a method of stretching, any conventionally known appropriate method can be used, such as stretching between 0 and 100 mm pinch, stretching with a tenter set stretching machine, etc. You may. The temperature during stretching may be any temperature as long as it is within the melting temperature of the foam, but it is preferably between room temperature and the softening temperature of the olefin thread resin constituting the foam.

The stretching ratio varies depending on the desired flexibility of the foam, but >i! ! ? It is best to stretch it 1-5 times or more. When stretched, the layers of the A-refined resins with different elongation and tensile strength of the L rollers that make up the foam are distorted, and the foam becomes open to some extent.
Development 1 (flexibility is expressed in the J body.

Since the flexible material made from zero foam is constructed as described above, it can be made in the cylinder by simply providing a holder for intermediation, and it has raw PC properties. Moreover, it is possible to obtain a foam that is economically 11-') excellent in IC flexibility. Therefore, the obtained foam can be used for clothing,
Suitable for use in sports and other applications that require performance such as flexibility, water absorption, and fit.

Hereinafter, the invention and manufacturing method for F wood will be explained with reference to examples.

Example elongation 200%, tensile strength (tensile strength) 250Kg/cd (
JIS K 1702), low density polyethylene 704 with density 0.923, melt index 4.0y/10min
704 parts, elongation 500%, tensile strength 450Kf/a
d.

Density 0.918, Me71/) Index 1 (1/1
0 minute linear low density polyethylene 3 (lfflhL part,
15 parts by weight of azodicarbonamide and 3.5 parts by weight of auxiliary agent F1
and 1C, melted with an extruder and extruded into a sheet with a thickness of 13 mm, and then 3.5 Mra with an electron beam irradiation machine.
441L, then 300
A foam sheet with a thickness of about 4 mm having uniform fine closed cells is heated by passing it through an A-thin at ℃ and expanding/fitting it by about 3 degrees. J ft o This foam sheet was rolled at room temperature between two pairs of pinch rolls with different speed ratios.
+l+stretched and continuous/2. A foam sheet with a high foam rate and flexibility and a diameter of approximately λ8 was prepared.

Table 1 shows the results of measuring the physical property values of the obtained foamed sheet and the physical property values of the stretched foamed sheet at n11.

Table 1: Measurement number: square, compressive strength: JIS K-6
767, using an open cell; p < ij air comparison formula specific gravity d1.

From Table 1, it can be seen that the foamed sheet obtained according to the present invention has an open cell ratio of +:':+< and flexibility.

Comparative Example A foamed sheet with a thickness of approximately 4 mm was produced in the same manner as in Example 1, except that the resin part in Example was replaced with the same 100% low density polyethylene as in Example. I tried to uniaxially stretch this foam sheet to double the original length at room temperature in the same way, but the foam sheet was cut midway through the inner conical stretch.

patent applicant Sekisui Chemical Co., Ltd. Representative Mototoshi Fujinuma

Claims (1)

[Claims] A method for producing a flexible foam, characterized by mixing and melting at least two types of olefins (three resins) having different elongation and tensile strength, foaming, and then stretching. 2. Elongation and tensile strength 3. The manufacturing method according to claim 1, wherein at least one of them differs by 20% or more. 3. The method of claim 1, in which the stretching is performed by L5 times or more. The manufacturing method according to item 2. 4. One type of secondary reflex (3-) fat is 10 to 9
Special K "Claim IIn" mixed in the range of 0 weight 1 廿%
1. Method of manufacturing the products described in Section 1 and Section 2 of Section 3.