JPH05254033A - Method of molding foam synthetic resin molding - Google Patents

Abstract

PURPOSE:To eliminate various disadvantages of a molding which is molded by filling up and then foam-fusing particles of a foam synthetic resin raw material into an internal foaming mold comprising a pair of molds. CONSTITUTION:The method consists of a process wherein a synthetic resin sheet made in a size capable of being applied at least on the surface of molding space (4) side of one mold (3) is fed between a pair of molds (2) (3), and next, between a pair of the molds (2) (3). particles of a foam synthetic resin raw material capable of being fused on the synthetic resin sheet are supplied and filled from the other mold (2) side, a process wherein one mold (3) is heated higher than the melting temperature of the synthetic resin sheet, a process wherein the synthetic resin sheet being applied on one mold (3) is permitted to heat-melt, and a process wherein an ordinal foam molding is effected between a pair of molds (2) (3).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded article obtained by filling foamable synthetic resin raw material particles into an in-mold foam molding mold composed of a pair of molds and foaming and fusing. The present invention relates to a method for molding a foamed synthetic resin molded article, which has been made in order to solve various drawbacks of the molded article.

[0002]

2. Description of the Related Art Conventionally, expandable synthetic resin raw material particles are filled in an in-mold foam molding mold composed of a pair of molds,
Molded products formed by foaming and fusing are lightweight, easy to handle, and have excellent cushioning performance.
Widely used in storage boxes.

[0003]

However, although such a general foamed synthetic resin molded article has a very thin skin on its surface, when it is rubbed or hit by another object, this skin is It may be easily peeled off or the surface may be easily dented. In addition, such a phenomenon tends to occur more easily when it is repeatedly used or washed with water. Further, this skin is formed by foaming and fusing a large number of raw material particles,
Since it is not thick and continuous, there are problems that the overall strength is low and it is brittle. Further, there is also a problem that individual raw material particles appear on the surface as a hexagonal pattern, and dents are formed between the raw material particles, so that the surface condition is not necessarily beautiful.

From these reasons, it is considered that a non-foamed synthetic resin sheet is attached to the surface of a molded foamed synthetic resin product after molding to form a surface coating, but it is melted to such an extent that only the surface is bonded. It is extremely difficult to work without causing wrinkles on the synthetic resin sheet in either case of attaching or adhering with an adhesive. This tendency is particularly remarkable when the shape of the molded article on which the surface coating is provided is complicated. It is also conceivable that the surface of the molded product is heated and melted by post-processing after the molding to form a surface coating. In this case, not only two molding steps are required, but also it is difficult to uniformly melt the raw material particles, and there is a problem that the surface of the molded product becomes wavy.

Further, it has also been attempted to insert a non-foamed synthetic resin sheet into the in-mold foam molding die before filling the expandable synthetic resin raw material particles, and then perform foam molding. However, it is troublesome to insert the non-foamed synthetic resin sheet into the mold, and there is a problem that the surface is not finished beautifully due to the generation of wrinkles and the like.

What has been invented in view of the above conventional problems is the method for molding a foamed synthetic resin molded article according to the present invention.
The purpose of the present invention is to fill various molds for foaming synthetic resin raw material particles into a mold for in-mold foam molding, which is composed of a pair of molds, and to solve various drawbacks of a molded product formed by foam fusion. To do.

[0007]

In order to achieve such an object, according to claim 1 of the present invention, one of the molds for in-mold foam molding comprises a mold space side surface of one mold. At least a synthetic resin sheet of a size that can be attached is supplied between a pair of molds that have been opened, and then a foamable synthetic resin that can be fused to the synthetic resin sheet from the other mold side between the pair of molds. Supplying and filling raw material particles, a process of attaching a synthetic resin sheet to the molding space side surface of one mold, and a process of heating the molding space side surface of one mold above the melting temperature of the synthetic resin sheet, Molding from a synthetic resin sheet in an in-mold foam molding process consisting of a process of heating and melting a synthetic resin sheet attached to the molding space side surface of one mold and a process of performing normal foam molding between a pair of molds. Forming a surface coating on the product surface And gist molding method of the foamed synthetic resin molded article as symptoms. Further, in claim 2, separately, a synthetic resin sheet sized to be affixable to at least the molding space side surface of one of the molds for in-mold foam molding composed of a pair of molds is opened. It is supplied between a pair of molds, and then the expandable synthetic resin raw material particles that can be fused to the synthetic resin sheet are supplied and filled from the other mold side between the pair of molds to form a molding space for one mold. The process of attaching the synthetic resin sheet to the side surface, the process of heating the molding space side surface of one mold above the melting temperature of the synthetic resin sheet, and the synthetic resin attached to the molding space side surface of one mold A step of heating and melting the sheet, a step of heating the molding space side surface of the other mold to a melting temperature of the raw material particles or higher, and a step of heating and melting the raw material particles in contact with the molding space side surface of the other mold From the synthetic resin sheet in the in-mold foam molding process It is summarized as almost forming method of the foamed synthetic resin molded article, characterized in that is formed on the entire surface or the entire surface to the surface coating of the charge particle surface of the molded article. Then, in claim 3, preheating is performed before the synthetic resin sheet is supplied between the pair of molds opened. Further, in claim 4, the synthetic resin sheet is a non-foamed material.

[0008]

Thus, in the cushioning material, for example, the cushioning property is enhanced on the inner surface which is in direct contact with the contents, or a good surface coating with improved non-peeling property is formed. It is intended to form such a good surface coating on the outer surface exposed to. In addition, such a surface coating can be formed on the inner surface or the outer surface of the surface of various molded products, or separately on almost the entire surface or the entire surface.

[0009]

EXAMPLES The molding method of the foamed synthetic resin molded article according to the present invention will be described in more detail based on the in-mold foam molding die used therein.

When a box-shaped molded product 1 as shown in FIG. 1 is molded, an in-mold foam molding mold composed of a pair of cavity mold and core mold as shown in FIG. 2 is usually used. ing. In FIG. 2, 2 is a cavity mold, 3 is a core mold, and this pair of cavity molds 2
When the core mold 3 and the core mold 3 are closed, a molding space 4 for molding the molded product 1 is formed therebetween. The core mold 3 is retracted to the left side in FIG. 2 with respect to the cavity mold 2 so that the pair of cavity mold 2 and core mold 3 can be opened. Reference numeral 5 in the figure is a raw material filling feeder for supplying and filling the molding space 4 with the raw material particles of the expandable synthetic resin such as expandable polystyrene beads.
Reference numerals 6 and 7 denote heating chambers formed in a closed shape behind the cavity mold 2 and the core mold 3 on the side of the molding space 4, and 8 denotes a surface of the cavity mold 2 and the core mold 3 on the side of the molding space 4 and the heating chamber 6. , 7 is a ventilation opening for communicating the inside, 9 is a steam pipe having one end in both heating chambers 6, 7, 10 is a water pipe having one end inserted in both heating chambers 6, 7, 11 is Similarly, an air supply pipe having one end inserted into both heating chambers 6 and 7, 12 is a drain pipe, and 13 is a release pin provided on the cavity mold 2 side. Further, 14 is an injection nozzle provided in the water pipe 10 toward the rear of the molding space 4 side, and 15 is an air supply pipe 11
Similarly, an air supply port provided toward the rear of the molding space 4 side is shown at the end of the. Further, 16, 17 and 18 are back plates, side plates and inner plates, and 19 and 20 are cavity side surface members and core side surface members which form the surfaces of the cavity mold 2 and the core mold 3 on the molding space 4 side, respectively. Then, from the back plate 16, the side plate 17, the inner plate 18, the cavity side surface member 19, and the core side surface member 20, the cavity mold 2 and the core mold 3 are closed behind the molding space 4 side and heated. Chambers 6 and 7 are formed.

A molded product 1 as shown in FIG. 1 is molded in the following manner by utilizing such an in-mold foam molding mold. First, a pair of cavity mold 2 and core mold 3 are closed, leaving a so-called cracking gap, and the molding space 4 is filled with foamable synthetic resin raw material particles through a raw material filling feeder 5. Then, the pair of cavity mold 2 and core mold 3 are completely closed, and both heating chambers 6 and 7 are closed.
The steam is supplied from the steam pipe 9 to the raw material particles, and the raw material particles are foamed and fused to form the molded article 1. After that, the injection nozzle 14 of the water pipe 10
Cooling water is sprayed in a mist form to cool the cavity mold 2 and the core mold 3, and compressed air or the like is further blown from the air supply port 15 of the air supply pipe 11 to remove the cavity mold 2 and the core mold 3. Cools and disperses and removes water. Then, the pair of cavity mold 2 and core mold 3 are opened, and the molded product 1 is taken out from the molding space 4 by the operation of the release pin 13.

However, although such a molded article 1 has a very thin skin on the surface, when it is rubbed or hit by another object, the skin is easily peeled off or the surface is easily removed. It gets depressed. In addition, such a phenomenon tends to occur more easily when it is repeatedly used or washed with water. Then, in the molded article 1 such as a returnable box in which the contained items are repeatedly used and contained and stored frequently, such a phenomenon remarkably appears on the inner surface which rubs against the contained items and may not be used for a long period of time. Further, there is a problem that the whole strength is small and it is brittle.

Therefore, in the present invention, the molten resin layer obtained by temporarily heating and melting the non-foam synthetic resin sheet in the in-mold foam molding process is solidified on the inner surface of the molded article 1 shown in FIG. The surface coating 21 is provided from the solidified resin layer thus formed.

In order to mold such a molded article 1, in the present invention, the core side surface member 20 of the core mold 3 for molding the inner surface of the molded article 1 is replaced with the conventional one shown in FIG. A core-side surface member shown as 22 in FIG. 3 is used. This is because a partition wall 23 is provided behind the molding space 4 side to form a closed heating gap 24.
A cast-in heater 25 serving as a heating means is internally provided in 24. By the way, the conventional core side surface member 20 has the structure shown in FIG.
As shown in FIG. 5, the ventilation opening 8 is provided, but after forming the surface coating 21 on the surface side of the core side surface member indicated by 22 in this figure, the normal in-mold foam molding process is performed. Such ventilation openings 8 are not provided as they often do not pass the steam used in, or other heating media.

In order to mold the molded article 1 as shown in FIG. 1, first, the core side surface member 22 shown in FIG. 3 is replaced with the conventional core side surface member 20, and a pair as shown in FIG. As shown in FIG. 4, the mold for in-mold foam molding is composed of the cavity mold 2 and the core mold 3 of
As shown in FIG. 5, a pair of cavity mold 2 and core mold 3
When the mold is opened, a non-foamed synthetic resin sheet such as a polystyrene sheet having a width capable of being attached to at least the entire surface of the core mold 3 on the side of the molding space 4 corresponding to the upper side between the two. The synthetic resin sheet 26 is wound between a pair of cavity mold 2 and core mold 3 which are wound and opened.
A synthetic resin sheet supply unit 27 is provided for supplying. In the figure
Reference numeral 28 denotes a synthetic resin sheet 26 which is passed between the cavity mold 2 and the core mold 3 in which the synthetic resin sheet 26 has been opened, so that the synthetic resin sheet 26 is preheated at a melting temperature or lower and a softening temperature or higher. It is a preheating means. This preheating means 28 utilizes a heater or other suitable heating source.

Thus, a molded article 1 as shown in FIG.
Is molded as follows. First, the pair of cavity mold 2 and core mold 3 are opened, and the synthetic resin sheet 26 is fed from the sheet supply unit 27 between them as shown in FIG. Then, this is below the melting temperature and above the softening temperature, for example, in the case of polystyrene resin, the melting temperature is about 200 ° C.,
70 to 180 ° C., preferably 90 to 160 ° C., and more preferably 110 to 140 ° C., is preheated to be supplied by passing through a preheating means 28, and then as shown in FIG. This synthetic resin sheet 26 is provided on the cavity mold 2 side in the remaining molding space 4 between the cavity mold 2 and the core mold 3 which are closed with a gap of about 5 mm, so-called cracking gap, between them. The molding space 4 is formed by supplying and filling expandable synthetic resin material particles, such as expandable polystyrene beads, which can be fused to the synthetic resin sheet 26 from the raw material filling feeder 5 and are made of the same kind of resin as the synthetic resin sheet 26, for example. By filling the raw material particles with the synthetic resin sheet 26 on the surface of the core mold 3 on the side of the molding space 4, the operation of the first step of bringing the raw material particles into close contact with the synthetic resin sheet 26 is performed. Cormorant. At this time, although the ventilation opening 8 is not provided in the core mold 3, the cavity mold 2
The size relationship between the joint portions of the inner mold and the outer periphery of the core mold 3 is set so that a ventilation gap 29 as shown in FIG. 7 is formed. The compressed air is introduced from the ventilation opening 8 provided in the cavity mold 2 into the heating chamber 6 and from the ventilation gap 29 into the pair of cavity molds 2.
It is configured such that it can be discharged to the outside through a gap between the core mold 3 and the core mold 3, and the raw material particles can be supplied and filled into the molding space 4. In addition to the operation of the first step, before this, a casting heater serving as a heating means in which the molding space 4 side surface of the core mold 3 is housed in the heating gap 24 of the core side surface member 22. 25 is energized, the melting temperature of the synthetic resin sheet 26 or higher, for example, in the case of polystyrene resin 200 ℃
The operation of the second step of heating to a certain degree or more is performed. In addition, a pair of cavity mold 2 and core mold 3 which are performed in parallel with the process of supplying and filling the raw material particles into the molding space 4 or after the raw material particles are filled, are also used. After the mold is closed, the third process operation of heating and melting the synthetic resin sheet 26 attached to the surface of the core mold 3 on the molding space 4 side is performed between the pair of cavity mold 2 and core mold 3. . In this way, the synthetic resin sheet 26 is once heated and melted on the entire surface of the core mold 3 on the side of the molding space 4 to form a molten resin layer evenly and almost uniformly. By the way, the synthetic resin sheet 26 fed from the synthetic resin sheet supply section 27 between the pair of cavity molds 2 and the core mold 3 and supplied is attached to the entire surface of the core mold 3 on the molding space 4 side. The outer peripheral portion is formed into a pair of cavity molds by a cutting edge or a cutting blade provided in advance in one or both of the cavity mold 2 and the core mold 3 corresponding to the peripheral part of the surface of the core mold 3 on the molding space 4 side. When the mold 2 and the core mold 3 are completely closed, they are cut and separated. After that, the cooling water is sprayed in a mist form from the spray nozzle 14 of the water pipe 10 of which one end side is inserted into the heating chamber 7 of the core mold 3, and the molding space 4 side surface of the core mold 3 is, for example, 70 ° C. The core mold 3 is cooled and the moisture is scattered and removed by blowing compressed air from the air supply port 15 of the air supply pipe 11 to cool the core mold 3. In this way, the molten resin layer is solidified and a solidified resin layer is formed on the entire surface of the core mold 3 on the molding space 4 side. Next, the heating chamber 6 of the cavity mold 2
To the molding space 4 side surface of the cavity mold 2 is heated to a normal foam molding temperature, for example, in the case of polystyrene resin, about 105 to 110 ℃,
The operation of the fourth step for performing ordinary foam molding is performed. At this time, the steam supplied from the steam pipe 9 to the heating chamber 6 of the cavity mold 2 passes through the ventilation opening 8 and heats and melts the raw material particles in the molding space 4, and the raw material particles and the synthetic resin sheet 26. By flowing the solidified resin layer formed by solidifying the molten resin layer made to flow in the vertical and horizontal directions, the raw material particles are foamed and fused,
The solidified resin layer formed from the synthetic resin sheet 26 and the raw material particles in close contact with the solidified resin layer are fused. After that, the cooling water is sprayed in the form of mist from the spray nozzle 14 of the water pipe 10 of which one end side is inserted into the heating chamber 6 of the cavity mold 2 to cool it, and further compressed from the air supply port 15 of the air supply pipe 11. Air or the like is blown to cool the cavity mold 2 and scatter and remove water. Then, the pair of cavity mold 2 and core mold 3 are opened, and the molding space 4 side of the core mold 3 is heated from the molding space 4 to the melting temperature of the synthetic resin sheet 26 as shown in FIG. A molding in which a surface coating 21 is integrally formed from a solidified resin layer formed by solidifying a molten resin layer that is once heated and melted from a synthetic resin sheet 26 in an in-mold foam molding process on the inner surface corresponding to the entire surface. The product 1 is taken out by the operation of the release pin 13.

According to this molding method, the surface coating 21 formed of the synthetic resin sheet 26 attached to the entire surface of the molding space 4 side of the core mold 3 is integrated on the surface of the molded product 1, and the raw material particles are Synthetic resin sheet 26 with foam fusion
Then, a structure as schematically shown in FIG. 8 was formed in which the raw material particles which were in close contact with each other were fused. In addition, 30 in FIG. 8 constitutes the molded product 1 itself and is foamed and fused to each other.
The raw material particles fused with the surface coating 21 formed from the synthetic resin sheet 26 are shown.

Further, in such a molding method, besides using a styrene resin such as polystyrene, a polyolefin resin such as polyethylene or polypropylene, and various synthetic resins such as copolymers can be used. Of these, polyethylene and polypropylene are preferable because the surface coating 21 is easily formed. Further, since the polypropylene film has excellent bending resistance, it is effective in forming these hinges when molding a container having an integrated lid. In this molding method, either a crosslinked synthetic resin or a non-crosslinked synthetic resin can be used, but in order to form a good surface coating 21 from the synthetic resin sheet 26, the non-crosslinked synthetic resin can be preferably used. .

Furthermore, if the synthetic resin sheet 26 and the raw material particles can be fused, it is not necessary to use the same type of synthetic resin, and different types of synthetic resins can be used. When is polyethylene, the raw material particles are polypropylene, and in the case of polypropylene,
Polyethylene is available for each. When ethylene vinyl acetate is used for the synthetic resin sheet, polyethylene or polypropylene can be preferably used as the raw material particles.

Then, using the above-mentioned molding die,
When molding a molded product 1 as shown in FIG. 1, after the raw material particles are filled, the operation of completely closing the pair of cavity mold 2 and the core mold 3 and the operation of leaving a gap between them are repeated. It is also possible. In this case, after the pair of cavity mold 2 and core mold 3 are completely closed, the raw material particles may be refilled when a gap is opened between them.

In addition to the above-described operations, a synthetic resin sheet is placed between the pair of cavity mold 2 and core mold 3.
Cavity mold 2 and core mold 3 that are supplied with 26 and closed
Even if the first step of filling and supplying the raw material particles into the molding space 4 between them and the second step of heating the core mold 3 to the melting temperature of the synthetic resin sheet 26 or more are started at the same time, The second process may be started with a delay, or the second process may be started after the first process is completed.

Further, the core mold 3 for forming the surface coating 21 is higher than the melting temperature of the synthetic resin sheet 26 to be used,
In the above-mentioned example, the heating temperature is about 200 ° C. or higher. However, since the heating temperature varies depending on the resin used, it is considered to select the optimum temperature after actually performing the temporary molding. The lower the heating temperature, the more beautiful the surface condition of the molded article 1 to be molded.

Further, the core die 3 may be preliminarily formed to be thin so as to increase the heat loss, and the synthetic resin sheet 26 may be melted so that the temperature is naturally lowered to some extent. When the core mold 3 is in such a mode, it is possible to set the heating temperature excessively high and bring it into contact with the synthetic resin sheet 26 to cool it.

After the usual in-mold foam molding process, that is, the fourth process, when cooling only the pair of cavity mold 2 and core mold 3 or the cavity mold 2, the water pipe 10 is not used and the water is not sent. It is also possible to blow compressed air from the air supply port 15 of the trachea 11. In addition, when cooling water is sprayed from the spray nozzle 14 of the water pipe 10 to cool it and then the heating chambers 6 and 7 or only the heating chamber 6 is depressurized to further cool and scatter and remove water. There is also.

Even if the core side surface member 31 shown in FIG. 9 is used in place of the core side surface member 22 shown in FIG. 3, the same effect can be expected. This core-side surface member 31 is provided with a pair of opposed walls 32, 32 spaced apart on the side opposite to the molding space 4 side surface without closing the partition wall 23 behind the molding space 4 side. A heating gap 33 having a shape of a circle is formed, and a casting heater 25 serving as a heating means is incorporated in the heating gap 33. The water pipe 10 and the air supply pipe 11 are provided so as to penetrate the heating gap 33 of the core-side surface member 31, with the injection nozzle 14 and the air supply port 15 thereof facing the molding space 4 rear side.

By the way, when the above-mentioned molding die is used, the surface coating 21 cannot be formed on substantially the entire surface or the entire surface of the molded article 1. However, when the molding die outlined in FIG. 10 is used. It becomes possible to form the surface coating 21 on almost the entire surface or the entire surface of the molded article 1. In this molding die, not only the core mold 3 but also the partition wall 34 or a pair of opposing walls (not shown) are provided behind the molding space 4 of the cavity mold 2 to form a closed heating gap 35 or the illustrated gap. No, the heating gap of the same form as in FIG. 9 is formed. Then, also in this molding die, the operations of the first, second, and third steps are performed as described above. When the raw material particles are supplied and filled into the molding space 4, here, after the synthetic resin sheet 26 is supplied, the pair of cavity mold 2 and core mold 3 are larger than the conventional cracking gap, for example, about 10 to 50 mm. The mold is closed while leaving the gap of, and the raw material particles are supplied and filled into the remaining molding space 4 to fill the molding space 4. Further, the cavity die 2 is placed in parallel with the core die 3 to perform the operation of the fourth step of heating the raw material particles to the melting temperature or higher. Next, by performing the fifth step operation of completely closing the pair of cavity mold 2 and core mold 3, the raw material particles are forcibly pressed against the surface of the cavity mold 2 on the molding space 4 side and heated molding is performed. These are heated and melted in contact with the surface of the space 4 side, and a molten resin layer is formed there. Subsequent operations are performed in the same manner as described above.
According to this molding method, as schematically shown in FIG. 11, the raw material particles 20 inside the molded product 1 are in a compressed state without being foamed and fused, but have a thick continuous surface. Since the surface coating 21 is provided, the intended purpose of molding the molded product 1 having strength can be achieved. However, during such molding, a steam supply pipe having a ventilation opening is projected inside the molding space 4, and steam or another heating medium is blown into this pipe to foam and melt the raw material particles inside. It is also possible to wear it. Further, in this molding, if the surface coating 21 is formed from the synthetic resin sheet 26 and the raw material particles on almost the entire surface of the molded product 1 or on the entire surface, the inside of the molded product 1 is exposed through the opening formed on the surface or the opening remaining on the surface. It is also possible to discharge the raw material particles in an unfoamed and unfused state to the outside to form a hollow molded article.

In this molding method, the fourth step of heating the cavity mold 2 to a temperature above the melting temperature of the raw material particles and the fifth step of completely closing the pair of cavity mold 2 and core mold 3 are started at the same time. Alternatively, the fifth step may be started before the fourth step.

Regardless of the illustrated embodiment, the heating gap
It is also possible to flow heating oil or steam to 24, 33, and 35. Further, when the raw material particles are supplied and filled in the molding space 4, the raw material particles can be compressed and filled with compressed air. Furthermore,
Providing the ventilation opening 8 on the side of the molding space 4 of the synthetic resin sheet 26, the core mold 3 that is heated above the melting temperature of the raw material particles, and the cavity mold 2 is also considered as appropriate.

The synthetic resin sheet 26 may be made of foam.

The operation of preheating the synthetic resin sheet 26 before supplying it between the pair of cavity molds 2 and the core mold 3 in which the molds are opened can be omitted as occasion demands.

[0031]

The foamed synthetic resin molded article molded by the molding method according to the present invention as described above has a synthetic resin sheet on a part, almost the entire surface, or the entire surface thereof, and raw material particles once melted by heating. The molten resin layer was made, since a continuous surface coating with a thickness is formed from the solidified resin layer formed by solidifying again, without damaging the advantages of the conventional foamed synthetic resin molded article, rubbing, Even if it hits, it becomes possible to solve the problem that the surface is easily peeled off or easily dented. Further, the strength of the whole is increased by providing the surface coating, and the surface condition becomes beautiful. Further, when molding such a molded product, it is possible to use the conventional foam molding machine as it is and to slightly modify a part of the in-mold foam molding die, which is industrially very useful.

Further, in such a molding method, since the synthetic resin sheet is once heated and melted in the in-mold foam molding process to form the surface coating, the conventional in-mold foam molding procedure can be slightly changed. Not only is the work efficient, but there is no risk of wrinkling of the surface coating. In particular, when the synthetic resin sheet is preheated before being supplied between the pair of molds whose molds have been opened, it is possible to effectively prevent wrinkles from being generated in the surface coating. Furthermore, various designs can be attached to the surface of the surface coating by devising a suitable pattern such as engraving an appropriate pattern on the surface of the mold on which the surface coating is to be formed or providing a net-like object. However, if it is in a matte state, it is possible to further enhance the commercial value.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a foamed synthetic resin molded product molded by a molding method according to the present invention.

FIG. 2 is a vertical cross-sectional view showing an example of a conventional in-mold foam molding die.

FIG. 3 is a longitudinal sectional view showing an example of a main part of a molding die used in a molding method according to the present invention.

FIG. 4 is an explanatory view showing an outline of a molding die used in the molding method according to the present invention.

FIG. 5 is an explanatory diagram showing an outline of a relationship between a molding die and a synthetic resin sheet supply section.

FIG. 6 is an explanatory view showing an outline of a state where the molding die is closed with a cracking gap left.

FIG. 7 is a vertical cross-sectional view showing the main part of this molding die.

FIG. 8 is an explanatory view schematically showing the structure of a molded product molded by the molding method according to the present invention.

FIG. 9 is a vertical cross-sectional view showing another example of the main part of the molding die used in the molding method according to the present invention.

FIG. 10 is an explanatory view showing the outline of a molding die used in another molding method according to the present invention.

FIG. 11 is an explanatory view schematically showing the structure of a molded product molded by another molding method according to the present invention.

[Explanation of symbols]

 1 Molded product 2 Cavity mold 3 Core mold 4 Molding space 5 Raw material filling feeder 6 Heating chamber 7 Heating chamber 8 Venting opening 9 Steam pipe 10 Water pipe 11 Air supply pipe 12 Drain pipe 13 Release pin 14 Injection nozzle 15 Air supply Mouth 16 Back plate 17 Side plate 18 Inner plate 19 Cavity side surface member 20 Core side surface member 21 Surface coating 22 Core side surface member 23 Partition wall 24 Heating gap 25 Cast heater 26 Synthetic resin sheet 27 Synthetic resin sheet supply section 28 Preheating Means 29 Ventilation gap 30 Expandable synthetic resin raw material particles 31 Core side surface member 32 Opposing wall 33 Heating gap 34 Partition wall 35 Heating gap

Claims (4)

[Claims] 1. A pair of molds in which a synthetic resin sheet having a size that can be attached at least to a molding space side surface of one mold of an in-mold foam molding mold composed of a pair of molds is opened. Then, between the pair of molds, the foamable synthetic resin raw material particles that can be fused to the synthetic resin sheet are supplied and filled from the other mold side, and synthesized on the molding space side surface of one mold. A step of attaching the resin sheet, and a step of heating the molding space side surface of one of the molds to the melting temperature of the synthetic resin sheet or more,
Molding from a synthetic resin sheet in an in-mold foam molding process consisting of a process of heating and melting a synthetic resin sheet attached to the molding space side surface of one mold and a process of performing normal foam molding between a pair of molds. A method for molding a foamed synthetic resin molded product, which comprises integrally forming a surface coating on the product surface. 2. A pair of molds in which a synthetic resin sheet having a size that can be attached at least to a molding space side surface of one mold of a mold for in-mold foam molding composed of a pair of molds is opened. Then, between the pair of molds, the foamable synthetic resin raw material particles that can be fused to the synthetic resin sheet are supplied and filled from the other mold side, and synthesized on the molding space side surface of one mold. A step of attaching the resin sheet, and a step of heating the molding space side surface of one of the molds to the melting temperature of the synthetic resin sheet or more,
The process of heating and melting the synthetic resin sheet adhered to the molding space side surface of one mold, the process of heating the molding space side surface of the other mold above the melting temperature of the raw material particles, and the other mold Foaming characterized by forming a surface coating on the almost entire surface or the entire surface of the molded product from the synthetic resin sheet and the raw material particles in the in-mold foam molding process consisting of heating and melting the raw material particles in contact with the molding space side surface Molding method for synthetic resin moldings. 3. The method for molding a foamed synthetic resin molded article according to claim 1, wherein the synthetic resin sheet is preheated before being supplied between a pair of molds whose molds have been opened. 4. The method for molding a foamed synthetic resin molded article according to claim 1, wherein the synthetic resin sheet is a non-foamed body.