KR20010049539A - Process for producing foamed article - Google Patents

Abstract

PURPOSE: To scarcely bring about a fault for lowering surface properties of a molding such as a void or an air shortage or an insufficiency in filling when molded by providing specific number or more of discharge holes each having a specific hole size and molding by using a foaming machine having a nozzle portion having the holes of both ends at a specific distance. CONSTITUTION: A foaming machine having a nozzle portion 1 including three or more discharge holes 2 each having a hole size of 1 to 8 mm so that a distance W between the holes of both ends of 30 to 100 mm is used. The shape of the portion 1 is a shape for uniformly filling a liquid-like molding material supplied from a liquid-like molding material supply hole 3 in the portion 1. The hole sizes of the holes 2 may be the same or different. The portion 1 can be disassembled to facilitate cleaning therein and its material can manufacture a desired foamed molding. Thus, the foamed molding for scarcely bringing about a fault for lowering surface properties of a molding such as a void or an air shortage or an insufficiency in filling when molded can be manufactured.

Description

Foam molded article manufacturing method {PROCESS FOR PRODUCING FOAMED ARTICLE}

FIELD OF THE INVENTION The present invention relates to the manufacture of foam molded articles, specifically to the manufacture of foam molded articles, such as midsoles in shoe soles.

Generally, low pressure foamers used in the production of midsoles for urethane shoe soles are provided with one or two circular outlets with diameters of 5 to 10 mm.

However, when molding a midsole having a low density of about 0.25 g / cm ³ with such a foamer, the following defects are generated, i.e. defects such as voids (air accumulation generated inside the foamed molded article). This is caused or air deficiency (surface defects caused by insufficient filling of the liquid molding and / or foamed molded product in a mold having a complicated inner surface) occurs, and a filling shortage is likely to occur.

It is an object of the present invention to provide a method for producing a foamed molded article which does not cause surface defects such as voids or air deficiency in the molded foam and does not cause a filling shortage during molding.

1 is an explanatory view schematically showing a discharge part of a foaming machine used in the present invention.

Explanation of symbols on the main parts of the drawings

1 nozzle 2 discharge hole

3: supply hole of liquid molding material

These and other objects will be apparent from the following description.

According to the present invention, in the foamed molded article manufacturing method for molding a foamed molded article with a foaming machine having a nozzle, the nozzle has three or more discharge holes, each nozzle has an inner diameter of 1 to 8 mm, and is provided between the discharge holes at both ends. The distance W is 30 to 100mm.

The method uses a foamer with a nozzle. This nozzle has three or more discharge holes, the inner diameter of each nozzle is 1 to 8 mm, and the distance between the discharge holes at both ends is 30 to 100 mm. Therefore, a foamed molded article free of voids or side dressing defects and lack of filling can be produced.

1 is an explanatory view schematically showing a discharge part of a foaming machine used in the present invention.

As shown in FIG. 1, the nozzle 1 is provided with a plurality of discharge holes 2.

The shape of the discharge hole 2 is not particularly limited. For example, round, oval, triangular, square and the like. Among these, a circle is preferable.

In order to suppress the occurrence of air deficiency and voids in the produced molded foam, the number of discharge ports 2 is three or more. The preferable number of discharge ports 2 is 3-10 pieces, More preferably, 4-9 pieces, More preferably, they are 4-6 pieces. The outlets are arranged linearly along a line, or in two or three rows. Alternatively, the outlets can be arranged on one to three concentric circles. The distance between each adjacent discharge port 2 is not particularly limited. This distance is preferably 1.5 to 20 mm, preferably 2 to 15 mm, in order to suppress the generation of voids inside the foamed molded body.

The shape of the nozzle 1 is also not particularly limited. Preferably, this nozzle takes the shape suitable for uniformly filling the nozzle 1 with the liquid molding material supplied from the hole 3 (supply hole of a liquid molding material). The distance between the discharge holes 2 located at both ends in order to uniformly disperse the liquid molding material in the mold, thereby suppressing the air deficiency phenomenon of the side face of the molded product and also sufficiently filling the nozzle 1 with the liquid molding material. W is preferably 30 to 100 mm, more preferably 40 to 60 mm.

The inner diameter of each discharge hole 2 is 1 mm or more, preferably 2 mm or more for cleaning the inside of the nozzle 1, and the possibility of releasing the liquid molding material and filling of the nozzle 1 with the liquid molding material. For this purpose, it is 8 mm or less, preferably 6 mm or less. The inner diameter of each discharge hole 2 is the same or different. The discharge holes are preferably arranged in a linear manner, and the inner diameter of each discharge hole located at both ends is preferably equal to or larger than 0 to 3 mm for the discharge holes other than the holes located at both ends, which is excellent on the side of the molded part. This is to give appearance appearance and to prevent air deficiency. In this case, the discharge holes are preferably arranged linearly. In particular, the discharge holes are arranged in a linear manner and each inner diameter of the discharge holes located at both ends is 2 to 6 mm, and the inner diameters of the discharge holes other than the holes located at both ends are 2 to 5 mm and are located at both ends. The inner diameter of the discharge hole is required to be equal to, or 0 to 3 mm, preferably 0 to 2 mm, more preferably 0 to 1 mm larger than the other discharge holes than the holes located at both ends.

The distance between the upper end and the lower end of each discharge hole 2, that is, the distance of the discharge hole 2 (hereinafter referred to as "distance L") is not particularly limited. In order to be able to wash the inside of the nozzle 1, it is preferable that the said distance L is 10 mm or less, More preferably, it is 5 mm or less.

The nozzle 1 is preferably decomposable for internal cleaning thereof.

The material for the nozzle 1 is not particularly limited as long as a molded article having the required shape can be produced. Such materials include metals such as iron, stainless steel, copper, aluminum and aluminum alloys, resins such as epoxy resins and phenolic resins and rubber.

The material of the mold used in the present invention is not particularly limited. Examples of such a material include the same materials as those for the nozzle 1 described above. The shape of the mold inner surface is not particularly limited, and this shape can be appropriately adjusted to suit the shape of the molded article required. In order to improve mold release properties, it is preferable to provide the mold release agent in advance to the inner surface of the mold by coating, spraying, dipping, or the like. Examples of the mold releasing agent include dimethyl silicone oil, mineral oil, paraffin wax and the like, and the present invention is not limited to these examples.

Liquid molding materials include polyurethanes, epoxy resins, phenolic resins, polyesters, urea resins, resins such as polyethylene and polypropylene, olefin resins and styrene resins, natural rubber, isoprene rubber, chloroprene rubber, styrene-butadiene rubber, butadiene Rubbers such as rubber, acrylonitrile-butadiene rubber, ethylene-propylene rubber, butyl rubber and acrylic rubber.

The liquid molding material may be one that can be molded into a foam molding during molding. Examples of the liquid molding agent for the foamed molded article include self-expanded polyurethane, olefin resin, styrene resin and the like. When using an olefin resin, a styrene resin, etc., the process of foaming resin in advance and foaming pre-foamed resin particle, or the process of immersing a foaming agent in resin, and foaming resin in a mold can be employ | adopted.

The process of the present invention provides an excellent effect, in particular for polyurethanes, which are susceptible to surface deterioration during molding. Representative examples of polyurethanes include polyether polyurethanes, polyester polyurethanes, and the like.

The raw material for polyurethane is not specifically limited, A well-known thing can be used. It is preferable to use a polyol solution and an isocyanate prepolymer as starting materials for polyurethane. The polyol solution comprises polyol components such as polyether-polyol and / or polyester-polyols, chain extenders, water, foam stabilizers (surfactants) and optionally also catalysts. Isocyanate prepolymers can be prepared from polyol components such as polyether-polyols and / or polyester-polyols and polyisocyanate components such as methylenediphenyl diisocyanate or modified compounds thereof. Polyether-polyols, polyester-polyols, chain extenders, foam stabilizers (surfactants), catalysts, polyisocyanate components and isocyanate prepolymers are known.

The method for producing a foamed molded article is the same as the conventional method, except that a foaming machine having three or more nozzles having an inner diameter of 1 to 8 mm and a distance W between the discharge holes at both ends of 30 to 100 mm is used. . As the foaming machine, a so-called injection foaming machine can be used. Using an auto-injection foaming machine, a remarkable effect can be obtained in suppressing the occurrence of air deficiency and harmful defects.

Further, in terms of labor saving, it is desirable to move the discharge hole linearly while the mold is filled with the liquid molding material.

Then, after molding, the molded article having the given shape is removed from the mold. The final molded part will have good surface properties even if it is a complex shape, since the occurrence of harmful defects such as air deficiency is suppressed. This effect is further enhanced, especially when the molded article is made of polyurethane foam. In particular, the effect is remarkable for pulley polyurethane foams for shoe soles with complex sides.

In general, shoe soles are classified into outsoles used for sandals and men's shoes and midsoles used for sports shoes. The effect of the invention is particularly pronounced for midsoles with low densities. Therefore, the method of the present invention can be particularly suitably employed when producing the midsole of a shoe sole.

In view of the reduction of the phenomenon of air deficiency, the density of the foamed molded article such as polyurethane foam is preferably 0.10 g / cm ³ or more, 0.45 g / cm ³ or less, more preferably 0.15 g / cm ³ or more, 0.30 g / cm ³ or less, particularly preferably 0.20 g / cm ³ or more and 0.30 g / cm ³ or less.

Example

Examples 1 to 24 and Comparative Examples 1 and 2

As the test mold, an iron mold having the same internal shape as the midsole was used. The midsole was about 3mm deep on the side, 30cm long, up to 10cm wide, at least 6cm wide and 4cm heels high. The temperature of the test mold was adjusted to 60 ° C ± 2 ° C. A mold releasing agent (manufactured by Kao Corporation, trade name "PURAPOWER 2060") was sprayed on the inner surface of the mold, and then wiped off with a mop.

The discharge part of the foamer is T-shaped as shown in FIG. The discharge section used in Examples 1 to 22 has holes arranged linearly at regular intervals. In addition, the discharge sections used in Examples 23 and 24 have six discharge holes arranged at regular intervals, drawing a circle having a radius of 20 mm, and one discharge hole located at the center. The distance W between the inner diameter of the discharge hole and the discharge holes located at both ends is shown in Table 1.

One tank of the injection-type low pressure foamer was filled with an isocyanate prepolymer (manufactured by Kao, Ltd., trade name "EDDYFOAM B-3321"), and the liquid temperature was adjusted to 35 ° C. In another tank, 100 parts by weight of a liquid polyol composition (manufactured by Kao Corporation, trade name "EDDYFOAM AS-6-52U"), 1.3 parts by weight of catalyst (manufactured by Kao Corporation, trade name "EDDYFOAM AS-651-60C"), A liquid mixture prepared by mixing 2 parts by weight of a crosslinking agent (manufactured by Kao Corporation, trade name "EDDYFOAM AS-60E") and 0.5 parts by weight of foam stabilizer (manufactured by Kao Corporation, trade name "EDDYFOAM AS-11S") was charged, The liquid temperature was adjusted to 40 ° C.

The isocyanate prepolymer was stirred in a low pressure foamer and mixed with the liquid mixture to bring the isocyanate index to 100. The final mixture was poured linearly into the mold from the heel to the toe to allow foaming. Five minutes after injection, the molded article made of polyurethane foam was taken out of the mold. This procedure was repeated to obtain 10 molded articles. Each molded article had a density of about 0.28 g / cm ³ and a C hardness of 60 ± 2.

Example 25

The same test mold as in Examples 1 to 24 was used and the temperature of the mold was adjusted to 60 ° C ± 2 ° C. A mold releasing agent (manufactured by Kao Corporation, trade name "PURAPOWER 2060") was sprayed on the inner surface, and then wiped off with a mop.

The discharge part of the foamer is T-shaped as shown in FIG. The discharge section has holes arranged linearly at regular intervals. The distance W between the inner diameter of the discharge hole and the discharge holes located at both ends is shown in Table 1.

One tank of the injection-type low pressure foamer was charged with an isocyanate prepolymer (manufactured by Kao, Ltd., trade name "EDDYFOAM B-3021"), and the liquid temperature was adjusted to 35 ° C. In another tank, 100 parts by weight of a liquid polyol composition (manufactured by Kao Corporation, trade name "EDDYFOAM AS-6-35F"), 0.9 parts by weight of catalyst (manufactured by Kao Corporation, trade name "EDDYFOAM AS-651-60C"), and A liquid mixture prepared by mixing 2 parts by weight of a crosslinking agent (manufactured by Kao Corporation, trade name "EDDYFOAM AS-60E") was charged, and the liquid temperature was adjusted to 40 ° C.

The isocyanate prepolymer was stirred in a low pressure foamer and mixed with the liquid mixture to bring the isocyanate index to 100. The final mixture was poured linearly into the mold from the heel to the toe to allow foaming. Five minutes after injection, the molded article made of polyurethane foam was taken out of the mold. This procedure was repeated to obtain 10 molded articles. Each molded part had a density of about 0.35 g / cm ³ and a C hardness of 60 ± 2.

The physical properties of the ten molded articles obtained in Examples and Comparative Examples were evaluated in the following manner. The results are shown in Table 1.

[Air deficiency and void]

It was observed whether the air deficiency was present in the protruding part of the side rig and whether the void was found inside the molded article, and the evaluation was made according to the following evaluation criteria.

[Evaluation standard]

: Less than 2 air deficiency and voids

: 3 ~ 5 generation of air deficiency and void

X: 6-10 generation | occurrence | production of an air deficiency part and a void

Table 1

As can be seen from the results shown in Table 1, all the foamed molded articles made of the polyurethane foams obtained in Examples 1 to 25 were substantially free of air deficiency or voids.

As described above, the present invention can produce a foamed molded article which does not cause surface defects such as voids or air deficiency in the foamed molded article and does not cause filling shortage during molding.

Claims (6)

A foam molded product manufacturing method for molding a foamed molded product with a foaming machine having a nozzle, wherein the nozzle has three or more discharge holes, each nozzle has an inner diameter of 1 to 8 mm, and a distance W between the discharge holes at both ends is 30 to Method for producing a molded foam, characterized in that 100mm. 2. The discharge holes of claim 1, wherein the discharge holes are arranged in a linear manner, and the inner diameter of each of the discharge holes located at both ends is equal to or larger than 0 to 3 mm than the discharge holes other than the discharge holes located at both ends. Foam molded article manufacturing method. The method according to claim 1 or 2, wherein the discharge holes move linearly when the liquid molding material is injected into the mold. The method according to claim 1, wherein the foamed molded product is made of polyurethane foam. The method for producing a foamed molded product according to claim 4, wherein the density of the foamed molded product of the polyurethane foam is 0.15 g / cm ³ or more and 0.45 g / cm ³ or less. The method of claim 1, wherein the foamed molded product is a midsole of a shoe sole.