JPH1015973A - Production of synthetic resin in-mold foamed molded object fitted with skin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To certainly remove a drain which remains in a mold, by setting one of molds to an upper mold and setting the other one of them to a lower mold at least on the way of steam heating or before foaming of foamable beads. SOLUTION: After foamable beads 7 are steamed, that is, on the way of steam heating and before foaming of foamable beads 7, one mold 3 is set to an upper mold and other mold 4 is set to a lower mold. The pressure reducing valve B2 connected to the chamber 4b of the other mold 4 is opened to evacuate a mold 6 from a steam hole 4c. By this constitution, gravity is rather utilized without opposing gravity to make it possible to simply suck out drain from the low steam hole 4c. Therefore, drain can be certainly removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a foamed synthetic resin mold with a skin used for, for example, interior materials for automobiles.

[0002]

2. Description of the Related Art As a conventional method of manufacturing a foamed molded article in a synthetic resin mold with a skin, for example, a thermoplastic resin skin material is used in one of two molds constituting a molding die. After placing and closing the mold, the molding beads are filled with foam beads, and the foam beads are foamed by steam heating to be fused together, and the foam beads and the thermoplastic resin skin material are fused and integrated. A so-called simultaneous integral molding is known.

[0003] In this method, when the two dies can be closed and opened in the vertical direction, the one of the dies is used to facilitate placement of the thermoplastic resin skin material. It is a lower mold.

[0004]

However, in the above case, the foam beads are foamed by the steam heating. Therefore, during the steam heating and before the foam beads are foamed, the inside of the molding die is required. To drain (moisture)
Therefore, there is a problem that the residual drain causes defective fusion of the foam beads to the synthetic resin foam molded article obtained by foaming the foam beads in the mold.

The present invention has been made in view of the above circumstances and problems. In so-called simultaneous integral molding, defective fusion to a synthetic resin foam molded article obtained by in-mold foaming of foam beads is performed. It is an object of the present invention to provide a method for producing a foamed molded article in a synthetic resin mold with a skin, in which no foaming occurs.

[0006]

Means for achieving the above object are as follows. First, a thermoplastic resin skin material is disposed on one of two molds constituting a molding die. After closing the mold, fill the molding die with foam beads,
The method for producing a foamed synthetic resin-in-mold molded article with a skin, in which the foamed beads are foamed by steam heating and fused together, and the foamed beads and the thermoplastic resin skin material are fused and integrated, In the middle of the step and before the expansion of the expanded beads, the one mold is an upper mold and the other mold is a lower mold.

Second, the foam beads are foamed after drains remaining in the mold are removed.

Third, after the foaming beads are filled in the mold, steam is supplied from a steam hole formed in the other mold so that the foaming beads are melted at a temperature lower than a temperature at which the foaming beads are fused to each other. Is preheated, and the foamed beads are steamed while maintaining the state for a predetermined time with steam, and then the foamed beads are fully heated at a temperature higher than a temperature at which the foamed beads are fused to each other.

Fourthly, after forming a thermoplastic resin skin material in the molding die and disposing it in the one mold, the molding beads are filled with the foam beads.

Fifth, at least a portion of the one mold on which the thermoplastic resin skin material is disposed is a permeable metal mold, a permeable ceramic mold, or a permeable electromold.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1 to FIG.
In the method for manufacturing the foamed synthetic resin in-mold 1 according to the embodiment, the thermoplastic resin skin material 5 is arranged in one of the two molds 3 and 4 constituting the mold 2. After the mold is closed, the inside of the molding die 6 is filled with foam beads 7, and the foam beads 7 are foamed by steam heating and fused to each other, and the foam beads 7 and the thermoplastic resin skin material 5 are fused. In the method for manufacturing the foamed synthetic resin mold 1 with a skin to be integrated, one of the molds 3 is used as an upper mold and the other is formed during the heating of the steam and before the foaming of the foam beads 7. The mold 4 is a lower mold.

That is, as shown in FIG. 1, first, the thermoplastic resin skin material 5 is placed in the one mold 3 and clamped.

Here, the molding die 2 is composed of two dies 3, 4 which can be closed and opened in the vertical direction, and one of the dies 3 is an upper die, and The other mold 4 is a lower mold.

The one mold 3 has, for example, a concave cross section and a chamber 3b formed therein.
A plurality of decompression holes 3c communicating with the chamber 3b are formed on the side a. The steam valve A1, the pressure reducing valve B1, and the drain valve C1 are connected to the chamber 3b.

The other mold 4 has, for example, a convex cross section and a chamber 4b formed therein.
A plurality of steam holes 4c communicating with the chamber 4b are formed on the side a. A steam valve A2, a pressure reducing valve B2, and a drain valve C2 are connected to the chamber 4b, respectively, and a feeder 8 for filling the foaming beads 7 into the mold 6 is provided.

Examples of the thermoplastic resin skin material 5 include a thermoplastic resin sheet made of a vinyl chloride resin or a polyolefin resin such as a polyethylene resin or a polypropylene resin. Since the thermoplastic resin skin material 5 is used as a skin of the foamed synthetic resin mold 1 with a skin, it may be colored to a desired color with a coloring agent or the like according to its use.

This thermoplastic resin skin material 5 is applied to one mold 3
What is necessary is just to arrange | position what was previously shape | molded by the other shaping | molding die etc. by vacuum molding etc. so that it may match the shape of the surface 3a of the said one metal mold | die 3. In this case, the pressure between the one mold 3 and the thermoplastic resin skin material 5 is reduced through the decompression holes 3c and the like, and the thermoplastic resin skin material 5 is fixed to the one mold 3 by suction or the like. do it.

Alternatively, the thermoplastic resin skin material 5 can be molded in the molding die 6 and disposed on the one mold 3. In this case, as described above, the thermoplastic resin skin material 5
There is an advantage that it is possible to omit the trouble of pre-forming with a molding die or the like in advance. Examples of the molding method include vacuum molding and slush molding.

Here, when the obtained molded article 1 in the synthetic resin mold with a skin requires, for example, a fixture for attaching to another member, the surface 4a of the other mold 4 is required.
In advance, an insert material (not shown) of a predetermined shape is arranged in advance, and when the foam beads 7 are foamed in the mold, the foam beads 7 are foamed and fused together to form a synthetic resin mold foam molded article. The insert material may be integrated with the insert material.

Next, as shown in FIG. 2, foam beads 7 are filled from the feeder 8 into the mold 6.

Examples of the synthetic resin constituting the expanded beads 7 include a polyolefin resin and a polystyrene resin.

Examples of the polyolefin resin include low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, ethylene-
Vinyl acetate copolymer, propylene homopolymer, ethylene-propylene random copolymer, ethylene-propylene block copolymer, ethylene-propylene-butene random terpolymer, propylene-vinyl chloride copolymer, propylene-butene copolymer Examples include a polymer, a propylene-maleic anhydride copolymer, a polyethylene resin such as poly (butene-1) and a polypropylene resin, and these can be used alone or as a mixture of two or more.

The polyolefin resin is preferably in a non-crosslinked state, but may be crosslinked by peroxide or radiation.

A mixture of this polyolefin resin and another thermoplastic resin can also be used. When mixed with the polypropylene resin, examples of such a thermoplastic resin include low-density polyethylene, linear low-density polyethylene, vinyl aromatic polymer, polybutene, and ionomer. When mixed with the polyethylene resin, examples thereof include a vinyl aromatic polymer, polybutene, and an ionomer. In these cases, the blending amount of the thermoplastic resin is preferably 20 parts by weight or less, more preferably 5 to 10 parts by weight, based on 100 parts by weight of the polyolefin resin.

The foamed beads 7 are formed, for example, from the above-mentioned synthetic resin into particles in advance, and a volatile foaming agent is added to the synthetic resin particles in a pressure vessel. After dispersing and heating to a predetermined foaming temperature under pressure, the aqueous dispersion may be manufactured in a prefoamed state by, for example, releasing the aqueous dispersion to a low pressure region.

If the expansion ratio when the expanded beads 7 are expanded in the mold is smaller than 3 times, the cushioning properties and the like of the obtained molded article in the synthetic resin mold tend to be reduced. When it is large, the shrinkage of the foamed molded article in the synthetic resin mold becomes large, and it tends to be too soft and the strength or the like tends to be reduced. It is preferably from 45 to 45 times, particularly preferably from 10 to 35 times. As such foam beads 7, for example, Eperan PP (trade name,
(Kanebuchi Chemical Industry Co., Ltd., foaming ratio 15 times) can be preferably used.

At this time, a thermoplastic resin skin material 5 is disposed on the surface 3a of the one mold 3 and, in the clamped state, only from the steam hole 4c of the other mold 4 in the molding die. Since the air of 6 does not escape, in order to easily fill the foam beads 7, the mold may be opened slightly so that the foam beads 7 do not drop at the time of filling, and the air may escape from the gap.

The expanded beads 7 may be filled in the molding die 6 in a state in which a pressurized gas is previously penetrated into the inside and an internal pressure is applied, or the expanded beads 7 are compressed using the pressurized gas. It may be filled in a state, or may be filled as it is without applying internal pressure or compressing.

Further, in order to improve the adhesiveness between the synthetic resin in-mold foamed article obtained by in-mold foaming of the foam beads 7 and the thermoplastic resin skin material 5, the foam beads 7 may be used as necessary. An adhesive may be applied in advance to the back surface 5b of the thermoplastic resin skin material 5 that comes into contact. Examples of the adhesive include a synthetic resin solution in an organic solvent, a resin emulsion, a resin powder, and the like. Examples of the synthetic resin used for these include, for example, ethylene-vinyl acetate resin, polypropylene, polyethylene, ethylene-propylene copolymer, chlorinated polypropylene, chlorinated polyethylene, ethylene-propylene-butene terpolymer, Examples thereof include polyolefin resins such as a mixture thereof.

Then, as shown in FIG. 3, the steam valve A2 connected to the chamber 4b of the other mold 4 is opened to supply steam S from the steam hole 4c to the inside of the molding die 6, and the expanded beads 7 Is heated and foamed.

At this time, before the expanded beads 7 are fully heated at a temperature equal to or higher than the temperature at which the expanded beads 7 are fused together, the expanded beads 7 are preliminarily heated at a temperature lower than the temperature at which they are fused together. If so, the expanded beads 7 can be in a sufficiently heated state without fusing each other.

The temperature at which the foam beads 7 are fused to each other means that the foam beads 7 are filled in a mold 6 having a depth of about 50 mm, and steam S at a predetermined temperature (predetermined pressure) is applied to the mold 10 at a predetermined temperature.
This is the lowest temperature at which the foamed beads 7 are fused to each other when supplied to the inside of the molding die 6 for 20 seconds or less so that the shape of the foamed molded article in the synthetic resin mold can be maintained.

The temperature at which the expanded beads 7 fuse to each other depends on the type of synthetic resin used and the like.
After checking this temperature in advance, the temperature of the steam S at the time of the preheating may be set. If the temperature of the steam S is too low, the effect of the preheating tends to be insufficient, so that the temperature at which the foam beads 7 fuse to each other is T (° C.). −
35) to T (° C.), preferably (T-30) to (T
-3) (° C), more preferably (T-25) to (T-
5) It is desirable that the temperature be in the range of (° C.). Further, the pressure of the steam S may be appropriately adjusted so as to be in the above-mentioned temperature range.

After preheating as described above,
If the foamed beads 7 are steamed with steam S while maintaining the state for a predetermined time, the latent heat of the steam S supplied between the foamed beads 7 can be effectively used. There is an advantage that the foam beads 7 can be more uniformly heated, for example, when molding a foam molded article.

After the preheating, the steam may be steamed while the supply of the steam S is continued, or the steam may be steamed while the supply of the steam S is stopped and the drain valve C2 is opened as necessary. Is also good. The holding time during the steaming varies depending on the thickness of the foamed bead 7 layer in the mold 6, the size and shape of the foamed bead 7, the expansion ratio, and the like. On the order of about 3 seconds or more, it is desirable that the time is about 5 seconds or more, and more preferably about 10 seconds or more.

After the foam beads 7 are steamed with steam S, a drain (moisture) exists between the foam beads 7 and if the main heating is performed in this state, defective fusion of the foam beads 7 may occur. Therefore, it is desirable to remove the drain remaining in the mold 6.

As a method of removing the drain, for example, as shown in FIG. 4, a pressure reducing valve B2 connected to the chamber 4b of the other mold 4 is opened to evacuate the inside of the mold 6 from the steam hole 4c. And the like.

After the foam beads 7 are steamed with steam S, that is, during the steam heating and before the foam beads 7 are foamed, the one mold 3 is set to an upper mold, and Since the other mold 4 is a lower mold, if the above-described evacuation is performed, the drain is easily drawn out from the lower steam hole 4c using gravity without resisting gravity. Can be. Therefore, there is an advantage that the drain can be reliably removed, and the drain hardly remains in the mold 6.

Next, main heating is performed at a temperature higher than the temperature at which the foam beads 7 are fused to each other. As shown in FIG. 5, the main heating is performed by opening the steam valve A2 and supplying steam S from the steam hole 4c to the inside of the molding die 6.
At this time, as described above, if the inside of the mold 6 is evacuated to remove the drain after performing the steaming with the steam S, the steam S for the main heating is more smoothly removed. It can be supplied to the inside of the mold 6.

The temperature of the water vapor S at this time may be higher than the temperature at which the foam beads 7 fuse with each other.
If it is too high, the resulting molded article in synthetic resin mold 9
Since the shrinkage of the foamed beads 7 tends to be too large, it is desirable not to exceed a temperature 30 ° C. higher than the temperature at which the foam beads 7 are fused together, preferably 25 ° C. higher.

After the main heating as described above, it is desirable to maintain the state in order to sufficiently transfer the heat of the steam S to the foam beads 7. The time required for holding at this time is, for example, when the thickness of the seven layers of foam beads is 5
It is desirable that the length is about 2 seconds or more, and preferably about 5 seconds or more for about 0 mm. However, if the time is too long, the resulting synthetic resin molded foam 9 shrinks. It may be set appropriately within a range in which such shrinkage does not occur.

Next, when the mold 2 is opened, as shown in FIG. 6, a synthetic resin foam molded article 9 obtained by foaming the foam beads 7 in the mold and the synthetic resin mold foam 9 are formed. A foamed synthetic resin-in-mold 1a with a skin having ears 5c composed of the thermoplastic resin skin material 5 fused and integrated with the surface 9a of the molded body 9 is obtained.

The mold 2 may be cooled before opening the mold. Further, it is desirable that the obtained foamed molded article 1a in a synthetic resin mold with a skin is released from the molding die 2 and then cured and dried under normal pressure at 50 to 80 ° C. for about 3 to 24 hours. Further, as in this embodiment, in the case where the ear portion 5c is formed with the end portion of the thermoplastic resin skin material 5 remaining, after removing the mold, curing and drying as described above, and then removing the ear portion 5c. If the part 5c is cut,
It is possible to obtain the synthetic resin molded foam 1 with a skin shown in FIG.

As described above, the foamed beads 7 are preheated, steamed with steam S, and then fully heated. Since the synthetic resin-molded internal foam molded article 9 and the thermoplastic resin skin material 5 can be fused and integrated, and the drain can be reliably removed, the synthetic resin-molded internal foam molded article 9 includes foam beads 7. It is possible to manufacture the foamed synthetic resin-in-mold 1 with a skin that does not cause defective fusion.

As shown in FIG. 8, the method for manufacturing the foamed synthetic resin mold 1 with a skin according to the second embodiment is the same as that of the first embodiment except that the thermoplastic resin skin of the one mold 3 is used. The portion where the material 5 is arranged is constituted by a gas-permeable electroforming mold 13.

The air-permeable electroforming mold 13 has fine air holes communicating with the chamber 3b on the entire surface 3a or at an arbitrary position and has air permeability, and is manufactured by, for example, nickel electroforming. For example, Porous Denchu,
Product name, manufactured by Gangnam Special Sangyo Co., Ltd.).

As described above, since the air-permeable electroforming mold 13 has fine air holes on the entire surface 3a or at an arbitrary position, as described above, the thermoplastic resin skin material 5 is vacuumed. In the case of disposing in the one mold 3 by molding,
The escape of air and gas between the air-permeable electroforming mold 13 and the thermoplastic resin skin material 5 can be further improved. Therefore, the thermoplastic resin skin material 5 can be surely adhered to the surface 3a of the one mold 3, and the diameter of the ventilation hole is as small as about several tens μm to 100 μm. There is also an advantage that traces of these ventilation holes do not remain on the surface 5a of the material 5.

Instead of the air-permeable electroforming mold 13, a metal or ceramic particle is sintered under predetermined conditions to form fine air holes having a diameter of about several μm on the entire surface 3a or a gas-permeable metal mold. A ceramic type (for example, Porcelax II, trade name, manufactured by Shinto Kogyo Co., Ltd.) may be used.
Alternatively, a permeable metal mold in which fine air holes having a diameter of about 0.4 mm or less, preferably about 0.2 mm or less are mechanically formed with a drill or the like on the entire surface 3a of the metal mold or ceramic mold or at an arbitrary position. Alternatively, a permeable ceramic mold can be used.

As described above, in the first and second embodiments, since the thermoplastic resin skin material 5 is disposed in the one mold 3, the two molds 3 and 4 are vertically clamped. While the mold is opened, the one mold 3 is an upper mold, and the other mold 4 is a lower mold. However, the present invention is not limited to this, and at least during the steam heating and Before the foaming of the foam beads 7, the above condition may be used.

That is, for example, a molding machine or the like capable of changing the direction of clamping and opening the two dies 3 and 4 to an appropriate direction can be used. In this case, for example, in order to easily arrange the thermoplastic resin skin material 5 at first, the mold clamping and mold opening can be performed in a horizontal direction or the like, or the mold clamping and mold opening can be performed in the vertical direction and the one of the one The mold 3 is set as a lower mold, and during the steam heating and before the expansion of the foam beads 7, the mold can be closed and opened in a vertical direction, and the one mold 3 is set as an upper mold, and The other mold 4 is used as a lower mold so that the drain can be easily removed, and after the drain is removed, the obtained synthetic foam 1 with a skin can be easily removed again. A method of returning to the original state may be used.

The case where the one mold 3 is a concave mold (female mold) having a concave cross section has been described. However, the present invention is not limited to this.
Is convex (male) and the other mold 4 is concave (female)
It may be.

Further, before disposing the thermoplastic resin skin material 5 on the one mold 3, the surface 5 a of the thermoplastic resin skin material 5 is previously formed with irregularities for a product design pattern such as embossing. Alternatively, irregularities for a product design pattern such as leather grain may be formed on the surface 3a of the one mold 3 in advance, and when the foam beads 7 are foamed in the mold by the steam heating, heat may be generated. The product design pattern irregularities may be transferred to the surface 5 a of the plastic resin skin material 5.

[0053]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 A molding die was constructed by using a laminated sheet of a vinyl chloride resin sheet (thickness: 0.5 mm) and an extruded polypropylene resin sheet (thickness: 2.5 mm) as a thermoplastic resin skin material. One of the two molds is an upper mold and the other mold is a lower mold so that the vinyl chloride resin sheet side is in close contact with the surface of the one mold. The vacuum molding of the thermoplastic resin skin material was performed. Then
After clamping, Eperan P as foam beads into the mold
P (trade name, manufactured by Kanegafuchi Chemical Industry Co., Ltd., foaming ratio: 15 times, with an internal pressure of 2 kg / cm ² previously applied by air pressure) was filled.

Next, water vapor (0.7 kg / cm ² ) is supplied into the molding die from the vapor hole formed in the other mold, preheated, and the foamed beads are steamed for 5 seconds. The drain and the water vapor were sucked and removed using a vacuum pump so that the pressure in the mold became 500 mmHg or less.

Thereafter, the steam (3.
² to 3.7 kg / cm ² ) are supplied into the molding die, and are maintained for 3 to 5 seconds, after which they are fully heated, then cooled with water, and then left to cool, and the mold is opened to form a foamed molded article with a skin in the synthetic resin mold I got

Example 2 A laminated sheet of a polyolefin resin sheet (thickness: 0.75 mm) and a polypropylene resin extruded foam sheet (thickness: 2.5 mm) was used as a thermoplastic resin skin material.
Except that steaming was not performed, a foamed synthetic resin-molded body with a skin was obtained in the same manner as in Example 1.

Example 3 Eperan PP having a foaming ratio of 30 times as a foamed bead (trade name, manufactured by Kaneka Chemical Industry Co., Ltd., internal pressure of 2 kg / c in advance by air pressure)
m ² that granted) that it uses a point to supply steam pressure 0.5 kg / cm ² during the preheating, and the time of the heating steam pressure 2.4~2.8kg / cm ² Except for the point of supply, a foamed synthetic resin mold with a skin was obtained in the same manner as in Example 1.

Example 4 A laminated sheet of a polyolefin resin sheet (thickness: 0.75 mm) and an extruded polypropylene resin sheet (thickness: 2.5 mm) was used as a thermoplastic resin skin material.
A foamed synthetic resin mold with a skin was obtained in the same manner as in Example 3 except that steaming was not performed.

Comparative Example 1 A foamed synthetic resin mold with a skin was obtained in the same manner as in Example 1 except that one mold was used as a lower mold and the other mold was used as an upper mold.

Comparative Example 2 A foamed synthetic resin mold with a skin was obtained in the same manner as in Example 2 except that one mold was used as a lower mold and the other mold was used as an upper mold.

Comparative Example 3 A foamed synthetic resin mold with a skin was obtained in the same manner as in Example 3, except that one mold was used as a lower mold and the other mold was used as an upper mold.

Comparative Example 4 A foamed synthetic resin mold with a skin was obtained in the same manner as in Example 3 except that one mold was used as a lower mold and the other mold was used as an upper mold.

As described above, the physical properties of the foamed synthetic resin mold with skin obtained in Examples 1 to 4 and Comparative Examples 1 to 4 are (A) the fusion ratio of expanded beads and (B) the synthetic resin. The adhesiveness between the in-mold foam molded article and the thermoplastic resin skin material was examined by the following evaluation methods. Table 1 shows the results.

(A) Fusion rate of expanded beads In the obtained expanded molded article in a synthetic resin mold with a skin, a thin cut is made on the surface of the expanded molded article in a synthetic resin mold with a knife, and then the sheet is bent and broken. The fracture surface was observed. Then, the ratio of the broken area of the foamed beads was expressed in percentage and evaluated based on the following evaluation criteria.

[Evaluation Criteria] A: The fusion ratio of expanded beads is 60% or more B: The fusion ratio of expanded beads is 40 to 59% C: The fusion ratio of expanded beads is 20 to 39% or more D: Expanded beads Fusion rate of 19% or less

(B) Adhesiveness between the foamed molded article in the synthetic resin mold and the thermoplastic resin skin material The foamed molded article in the synthetic resin mold of the obtained synthetic resin molded foam inside the skin and the thermoplastic resin skin material are obtained. After peeling, the state of the interface was observed and evaluated based on the following evaluation criteria.

[Evaluation Criteria] A: Only material breakage is observed in the foamed molded article layer in the synthetic resin mold. B: Both the material breakage of the foamed molded article layer in the synthetic resin mold and the interface peeling between the foamed molded article layer in the synthetic resin mold and the thermoplastic resin skin material are observed. C: Interfacial separation between the foamed molded article layer in the synthetic resin mold and the skin material of the thermoplastic resin is observed. D: The synthetic resin molded foam layer and the thermoplastic resin skin material are not bonded.

[0069]

[Table 1]

[0070]

As described above, according to the first aspect of the present invention, at least during the steam heating and before the expansion of the expanded beads, the one die is set to the upper die and the other die is set to the upper die. Since the mold is a lower mold, if the inside of the mold is evacuated from the vapor hole or the like of the other mold, the drain remaining in the mold is lowered by using gravity without resisting gravity. It can be easily sucked out from the steam hole or the like. Therefore, there is an advantage that the drain can be reliably removed, and the drain hardly remains in the mold.

According to the second aspect of the present invention, since the foam beads are foamed after the drain remaining in the mold is removed, defective fusion of the foam beads to the foam molded article in the synthetic resin mold occurs. It is possible to produce a foamed molded article in a synthetic resin mold with a skin without the skin. In addition, when the inside of the mold is evacuated to remove the drain, there is an advantage that steam for heating and foaming the foam beads can be more smoothly supplied into the mold.

According to the third aspect of the present invention, after the foaming beads are filled in the molding die, steam is supplied from the steam holes formed in the other mold so that the temperature is lower than the temperature at which the foaming beads fuse with each other. The foamed beads are pre-heated at a temperature, and the foamed beads are steamed while maintaining the state for a predetermined time, and then the foamed beads are fully heated at a temperature equal to or higher than a temperature at which the foamed beads are fused to each other. By the preheating, the expanded beads can be in a sufficiently heated state without fusing to each other. In addition, since the latent heat of the steam supplied between the foamed beads can be effectively used by steaming with the steam, the foamed beads can be made more uniform, particularly when a foamed article in a synthetic resin mold having a large thickness is formed. There is an advantage that it can be heated. For this reason, it is possible to more effectively suppress the occurrence of defective fusion of the foamed molded article in the synthetic resin mold.

According to the fourth aspect of the present invention, after forming the thermoplastic resin skin material in the mold and disposing it in the one mold, the foam beads are filled in the mold.
There is an advantage that the labor for pre-molding the thermoplastic resin skin material with another molding die or the like can be omitted.

According to the fifth aspect of the present invention, at least a portion of the one mold where the thermoplastic resin skin material is disposed is made of a permeable metal mold, a permeable ceramic mold, or a permeable electromold, Since the thermoplastic resin skin material is disposed in the one mold by vacuum forming because it has fine ventilation holes on the entire surface or at an arbitrary position, the permeable electric mold or the like and the thermoplastic resin are used. The escape of air and gas between the resin skin materials can be further improved. for that reason,
The thermoplastic resin skin material can be more securely adhered to the surface of one of the molds, and the diameter of the ventilation hole is as small as several μm to several hundred μm or less, so that the surface of the thermoplastic resin skin material is reduced. Another advantage is that no trace of these vents remains.

[Brief description of the drawings]

FIG. 1 is an explanatory side cross-sectional view showing a state in which a thermoplastic resin skin material is arranged in one mold and the mold is clamped in a method of manufacturing a foamed molded article in a synthetic resin mold with a skin according to the first embodiment.

FIG. 2 is an explanatory side sectional view showing a state in which foamed beads are filled in a molding die.

FIG. 3 is an explanatory side sectional view showing a state in which steam is supplied into a mold after filling with foam beads.

FIG. 4 is an explanatory side sectional view showing a state where the inside of a mold is evacuated.

FIG. 5 is an explanatory side sectional view showing a state in which steam is supplied into a molding die to expand foam beads in the die.

FIG. 6 is a side cross-sectional view of a foamed molded article in a synthetic resin mold with a skin having ears removed from the mold.

FIG. 7 is a side sectional view of the foamed molded article in a synthetic resin mold with a skin after cutting the ears of FIG. 6;

FIG. 8 is an explanatory side cross-sectional view showing a state in which a thermoplastic resin skin material is arranged in one mold and the mold is clamped in the method of manufacturing a foamed synthetic resin mold with a skin according to the second embodiment.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 foamed synthetic resin in mold inside skin 2 molding die 3 one mold 4 other mold 4c vapor hole 5 thermoplastic resin skin material 6 inside mold 7 foam beads S steam 9 synthetic resin mold inside foam 13 Air permeable mold (or air permeable metal type, air permeable ceramic type)

Claims (5)

[Claims] Claims: 1. A thermoplastic resin skin material is placed in one of two molds constituting a molding die, and after clamping,
Filling the molding beads with foam beads, foaming these foam beads by steam heating and fusing them together,
In the method for producing a foamed molded article in a synthetic resin mold with a skin in which the foamed beads and the thermoplastic resin skin material are fused and integrated, at least during the steam heating and before foaming of the foamed beads, A method for producing a foamed molded article in a synthetic resin mold with a skin, wherein the mold is an upper mold and the other mold is a lower mold. 2. The method according to claim 1, wherein the foam beads are foamed after drains remaining in the mold are removed. 3. After the foaming beads are filled in the mold, steam is supplied from a steam hole formed in the other mold to pre-press the foaming beads at a temperature lower than a temperature at which the foaming beads fuse together. The method according to claim 1 or 2, wherein the foamed beads are heated and held for a predetermined time to evaporate the foamed beads with steam, and then the foamed beads are fully heated at a temperature higher than a temperature at which the foamed beads are fused to each other. A method for producing a foamed molded article in a synthetic resin mold with a skin according to the above. 4. A foaming bead is filled in a molding die after a thermoplastic resin skin material is molded in the molding die and arranged in the one die. The method for producing a foamed molded article in a synthetic resin mold with a skin according to any one of the above. 5. A permeable metal mold, a permeable ceramic mold, or a permeable electromold, wherein at least a portion of the one mold on which the thermoplastic resin skin material is disposed is made of a permeable metal mold, a permeable ceramic mold, or a permeable electric mold. A method for producing a foamed molded article in a synthetic resin mold with a skin according to the above.