JPH0985840A - Preparation of shape memory resin foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing efficiently a shape memory resin foam which is a foam with a thin thickness when it is applied but recovers the thickness after application and exhibits excellent sealaiblity and heat insulation properties. SOLUTION: A first process wherein a resin foam 10 is introduced between two endless belts 7 and 7 whose temp. is set below the softening pt. of the resin and whose gap is adjusted to the thickness of the resin foam 10, a second process wherein the resin foam 10 is gradually compressed in the thickness direction under a condition where the resin foam 10 is placed between two endless belts 8 and 8 and a third process wherein the resin foam is cooled under a condition where it is placed between two endless belts 9 and 9 to liquefy the foam gas in the resin foam 10, are continuously performed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a shape memory resin foam.

[0002]

2. Description of the Related Art Conventionally, as a heat insulating material for a house, a thermoplastic resin foam has been used for a lining of a half-roof for the purpose of sealing and heat insulation of a joint and between an inner wall and an outer wall for the purpose of wall heat insulation. The thermoplastic resin foam has excellent performance for the purpose of ensuring heat insulation and sealing properties, but is difficult to construct, for example, when it is used as a heat insulating material for the lining of a half-roof, it has a certain thickness. If the foams are stuck together, there is a problem that the joint between the foams becomes thick and the construction becomes difficult. On the other hand, when a thin foam is used, there is a problem that a predetermined heat insulating effect cannot be obtained.

Even when sandwiched as a heat insulating material in a wall gap, there is no problem in construction when the shape of the gap is constant. There was a problem that the construction was complicated and difficult in the place where it was.

Hitherto, as a sealing material for a gap, a material in which the cell wall of an open-cell foam is covered with chloroparaffin or the like by an impregnation method and the foam is pressure-bonded has been used.
In this compressed foam, the cell walls adhere to each other, but this adhesion is peeled off by the restoring (recovering) force of the foam, and the foam gradually returns to its starting structure. But,
Since this sealing material was obtained by impregnating the open-cell foam as described above and then compressing it, it did not have a sufficient sealing effect.

Therefore, a sealing material has been proposed in which a liquid impermeable layer is provided on a foam body to gradually restore the original shape after being compressed and deformed (Japanese Patent Publication No. 3-55621, Japanese Patent Laid-Open No. 193465/1989). JP-A-1-216169).

However, this sealing material requires (1) impregnation treatment, which is time-consuming, and (2) impregnated chloroparaffin or the like flows out of the foam, and is particularly used in an environment of high temperature. There are problems that the outflow is remarkable, and (3) the heat insulation performance is low because it is impregnated, and it cannot be used as a heat insulating material.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and its purpose is that the construction is easy because the thickness is thin at the time of construction, and the thickness is recovered after the construction.
An object of the present invention is to provide a manufacturing method capable of efficiently producing a shape memory resin foam that exhibits excellent sealing properties and heat insulating properties.

[0008]

A method of manufacturing a shape memory resin foam according to the present invention comprises two methods in which the temperature of the resin foam is set below the softening point of the resin and the gap is adjusted to the thickness of the resin foam. A first step of introducing between the endless belts, a second step of gradually compressing the resin foam in the thickness direction while sandwiched between the two endless belts, and a cooling between the two endless belts. The third step of liquefying the foaming gas in the resin foam is continuously performed.

The resin foam used in the present invention includes:
There is no particular limitation, and examples include those formed by extrusion foaming, those in which a foaming agent is pressed into molten resin in a pressure vessel and then foamed under normal pressure, and the like. Further, as the resin foam, it is preferable that the foaming gas is contained in the foaming cell immediately after production and the foaming gas is not yet replaced with air.

The resin used in the resin foam is not particularly limited as long as it has foamability, and examples thereof include polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-propylene-diene copolymer and ethylene. -Vinyl acetate copolymers, polybutes, olefin resins such as chlorinated polyethylene; polystyrene,
Styrene-butadiene-styrene copolymer, styrene-
Styrenic resin such as isoprene-styrene copolymer;
Polymethyl acrylate, polymethyl methacrylate,
Acrylic resins such as ethylene-ethyl acrylate copolymers; Vinyl chloride resins such as polyvinyl chloride and polyvinylidene chloride; 6-nylon, 66-nylon, 12
-Amide resins such as nylon; ester resins such as polyethylene terephthalate and polybutylene terephthalate; ABS resins, polycarbonates, polyacetals, polyphenylene sulfides, polyether ether ketones, polyether imides, silicon resins, thermoplastic polyurethanes, various elastomers, etc. Can be mentioned. Of these, particularly flexible polyethylene and polypropylene are preferable.

As the foaming agent used in the resin foam, a physical type foaming agent and a thermal decomposition type foaming agent can be used. The physical type foaming agent is preferably a gas having a higher permeability coefficient of gas generated from the foaming agent to the resin than that of air (for example, carbon dioxide gas). The boiling point or sublimation point of the foaming agent is preferably lower than the softening point of the resin. Here, the softening point means a glass transition point (Tg) in an amorphous resin and a melting point (Tg) in a crystalline resin.
m).

Examples of the physical type foaming agent include aliphatic hydrocarbons such as butane (boiling point: -0.5 ° C), pentane (36 ° C), hexane (69 ° C); benzene (80.1).
Aromatic hydrocarbons such as ℃); ketone hydrocarbons such as acetone (56 ℃); methanol (64 ℃), ethanol (7
8 ° C.) alcoholic hydrocarbons such as 1,1-dichloro-
1-fluoroethane (32 ° C.), 2,2-dichloro-
1,1,1-trifluoroethane (27.5 ° C), 1,
1,1,2-tetrafluoroethane (-26.3 ° C),
In addition to halogenated hydrocarbons such as monochlorodifluoroethane (-9.7 ° C) and monochlorodifluoromethane (-40.8 ° C), carbon dioxide gas (sublimation point: -78.5 ° C), nitrogen gas (-195.8 ° C) ) And the like, and these may be used alone or in combination of two or more kinds.

Among the above physical type foaming agents, those having a boiling point or sublimation point near room temperature are easy to control in temperature, and
1-dichloro-1-fluoroethane (32 ° C.), 2,2
-Dichloro-1,1,1-trifluoroethane (27.
5 ° C.) and pentane (36 ° C.) are preferred.

As the above-mentioned thermally decomposable foam material, a gas having a higher permeation coefficient of the gas generated from the foaming agent to the resin than that of air (for example, carbon dioxide gas generated from sodium bicarbonate) is preferable.

In the resin composition used in the present invention, a bubble nucleating agent, an antioxidant, a pigment, a flame retardant and the like may be added to the above resin.

Examples of the cell nucleating agent include calcium carbonate, talc, clay, magnesium oxide, zinc oxide, carbon black, silicon dioxide, titanium oxide, citric acid,
Examples include baking soda, orthoboric acid and talc, and alkaline earth metal salts of fatty acids.

The antioxidant is not particularly limited as long as it is generally used, and tetrakis [methylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate)] methane, thiodiene Dilauryl propylene acid, 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane and the like can be mentioned.

The above-mentioned flame retardants include bromine compounds such as hexabromophenyl ether and decabromodiphenyl ether; phosphoric acid compounds such as ammonium polyphosphate, trimethyl phosphate and triethyl phosphate; melamine derivatives; inorganic flame retardants and the like. These may be used alone or in combination of two or more.

The manufacturing method of the present invention comprises a first method described below.
~ The third step, for example, a manufacturing apparatus as shown in FIG. 1 is used. This manufacturing apparatus comprises a heating zone 1, a compression zone 2 and a cooling zone 3. Heating heaters 4 and 5 are provided in the heating zone 1 and compression zone 2, respectively, and a cooling blower 6 is provided in the cooling zone 3. There is.

In the first step, the resin foam 10 is introduced between the two endless belts 7, 7 provided in the heating zone 1 and conveyed in the direction of the arrow. The gap between the endless belts 7, 7 is adjusted so as to be the thickness of the resin foam 10, and the belt temperature is set by the heating heater 4 to be lower than the softening point of the resin, preferably higher than the boiling point of the foaming agent.

In the second step, the resin foam 10 is introduced between the two endless belts 8 provided in the compression zone 2 and conveyed in the direction of the arrow. The gap between the endless belts 7, 7 is set so as to be gradually reduced, and the thickness of the resin foam 10 is gradually compressed as it moves.

In the third step, the resin foam 10 is introduced between the two endless belts 9 provided in the cooling zone 3 and conveyed in the arrow direction while being cooled by the cooling blower 6. The cooled resin foam 10 is wound into a roll outside the apparatus. The cooling temperature in the third step is set below the boiling point of the foaming agent to liquefy the foaming gas in the foaming cells.

The above manufacturing apparatus may be installed immediately after the extruder for molding the resin foam or may be installed as a separate line. A steel belt is generally used as a material used for the endless belt. Examples of the heating method include an infrared panel heater and a heating blower.

(Operation) In the production method of the present invention, the resin foam is heated in the heating zone to a temperature equal to or higher than the boiling point of the foaming agent, and the foaming agent is vaporized. By adding it, the thickness can be efficiently reduced, and then by cooling to below the boiling point of the foaming agent, the foaming agent can be liquefied and the compressed state can be maintained.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto. (Example 1) As a resin, low-density polyethylene ("Yukaron ZC30" manufactured by Mitsubishi Petrochemical Co., melting point 109 ° C, MI =
2.8) A resin composition containing 100 parts by weight, an antioxidant (“Mark-328” manufactured by ADEKA ARGUS CORPORATION), and by weight talc (“MS” manufactured by Nippon Talc Co., Ltd.) as a cell nucleating agent. It is supplied from a hopper to a vent type screw type extruder (caliber φ65 mm, L / D = 35), and 1,1-dichloro-1-
Fluoroethane was injected at a rate of 15 g / min from a plunger pump, kneaded at 130 ° C., and then extrusion-molded at a rate of 10 kg / hour to produce 10 mm (thickness) × 500 m.
A resin foam of m (width) (foaming ratio 30 times) was obtained.

The resin foam obtained above was introduced into the manufacturing apparatus shown in FIG. 1 and compressed in the thickness direction under the conditions shown in Table 1 to obtain a shape memory resin foam having a thickness of 4 mm. The transport speed of the resin foam was 2 m / min, the production time required for all steps was 2 minutes, and the production speed was 20 kg / hour.

[0027]

[Table 1]

Comparative Example 1 A resin foam having a size of 10 mm (thickness) × 500 mm (width) obtained in the same manner as in Example 1 was heated in an oven at 60 ° C. for 2 minutes and then compressed at 25 ° C. (Pressurized area: 500 mm x 500 mm) 4
It was compressed to a thickness of mm, heated for 2 minutes, and then cooled for 1 minute and 30 seconds to obtain a shape memory resin foam. It takes 1 minute and 30 seconds for the opening and closing time of the press and the foam setting time, the production time required for all steps is 5 minutes, and the production speed is 1
It was kg / hour.

With respect to the shape memory resin foams obtained in the above Examples and Comparative Examples, the recovery rate of the thickness and the recovered thickness were measured after being applied as the lining of the folded roof, and the results are shown in Table 2.

[0030]

[Table 2]

[0031]

EFFECTS OF THE INVENTION The method for manufacturing a shape memory resin foam according to the present invention has the above-mentioned constitution, and the construction is easy because the thickness is thin at the time of construction. Providing a foam that exhibits heat insulation with high production efficiency. Therefore, the resin foam obtained by the manufacturing method of the present invention can be suitably used between the inner wall and the outer wall for the purpose of lining the folded-half roof and heat insulation of the wall.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a manufacturing apparatus used in a manufacturing method of the present invention.

[Explanation of symbols]

 1 heating zone 2 compression zone 3 cooling zone 4,5 heating heater 6 cooling blower 7,8,9 endless belt 10 resin foam

Claims (1)

[Claims] 1. A first step of introducing a resin foam between two endless belts, the temperature of which is set below the softening point of the resin and the gap of which is adjusted to the thickness of the resin foam. The second step of gradually compressing in the thickness direction while sandwiched between two endless belts, and the third step of liquefying the foaming gas inside the resin foam by cooling while sandwiched between two endless belts A method for manufacturing a shape memory resin foam, which is characterized in that