JPH0524104A - Method for molding open cell porous sheet material - Google Patents

Abstract

PURPOSE:To adapt vacuum molding, pressure forming and vacuum pressure forming to a molding material having air permeability. CONSTITUTION:A molding method contains a heating process softening a molding material A', a sealing treatment process superposing a non-perforated sheet B having elongation properties and flexibility on the molding material A, a mold register process arranging the superposed molding material A' and non- perforated sheet B to a mold 6 and a molding process making the pressure of the space facing to the molding material A' more negative than that of the space facing to the non-perforated sheet B to deform the non-perforated sheet B on the negative pressure side and pressing the molding material A' to the molding surface 61 of the mold 6 by the non-perforated sheet B. As the molding material A', a material having open cells formed thereto by expanding a sheet body wherein glass staple fibers are mixed with PP or PE can be used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an open-celled porous sheet material.

[0002]

2. Description of the Related Art An intermediate material such as a synthetic resin sheet material is used as a molding material, and the molding material is heated and softened and placed in a mold, and then the molding material is sucked and made to follow the molding surface of the mold. That is, the vacuum forming method, that the molding material is pressed with air pressure to follow the molding surface of the mold, and the molding material is arranged along the molding surface of the mold by using both the vacuum molding method and the pressure molding method. The vacuum pressure molding method has been conventionally known, and each of the above molding methods is suitable when a non-porous sheet material made of a thermoplastic resin such as polyvinyl chloride resin or methyl methacrylate resin is used as the molding material. Be implemented. And
These molding methods are said to be advantageous molding methods for high-mix low-volume production, as compared with the injection molding method of injecting raw materials into the molding space of a mold.

[0003]

However, when the molding material is a sheet material made of a porous material having open cells (open-celled porous sheet material), the molding material is sucked or air pressure is applied. Even if pressure is applied, the air circulates through the open cells of the molding material, so it is difficult for the molding material to have a suction action or a pressure action. Therefore, it has been conventionally difficult to apply each of the above-described molding methods utilizing pneumatic pressure when the molding material is a porous material having open cells.

The present invention has been made in view of the above problems. Even if the molding material is an open-cell porous sheet material, the above-mentioned vacuum molding method, pressure molding method, and It is an object of the present invention to provide a molding method to which the vacuum pressure molding method can be suitably applied.

[0005]

A method for forming an open-celled porous sheet material according to the present invention is a sheet material softened by heating, which is a porous material having open cells and has no pores on one side. The non-perforating treatment step of stacking sheets, the mold matching step of placing the molding material and the non-perforated sheet that have undergone the non-perforating treatment step in the mold, and the space facing the molding material after the mold matching step A forming step of deforming the non-perforated sheet to a negative pressure side by applying a negative pressure to the space facing the perforated sheet and pressing the forming material with the non-perforated sheet against the forming surface of the die.

[0006]

According to the present invention, even if the space facing the forming material is made to have a negative pressure than the space facing the non-perforated sheet, the non-perforated sheet prevents the air flow to the forming material. Then, the non-perforated sheet is deformed to the negative pressure side, and the non-perforated sheet pushes the molding material and presses it against the molding surface of the mold.

[0007]

EXAMPLES The method of the present invention comprises a non-perforating treatment step of stacking a non-perforating sheet on one surface of a molding material made of a porous material having open cells and softened by heating, and a non-perforating treatment step. A non-perforated sheet in which a molding material and a non-perforated sheet that have passed through the mold are placed in a mold, and a space facing the forming material is set to a negative pressure more than a space facing the non-perforated sheet after the mating step. While deforming the negative pressure side to the negative pressure side, and pressing the molding material against the molding surface of the mold with the non-porous sheet. Hereinafter, a molding method of the present invention according to an embodiment will be described with reference to FIGS. It should be noted that this example is an example conforming to the vacuum pressure forming method.

In the figure, A is a starting material, which is a sheet-shaped material made of a thermoplastic resin or a composite material mainly composed of a thermoplastic resin. A'is a molding material, which is an open-celled porous sheet material. B is a non-porous sheet, and this non-porous sheet has substantially no air flowability.

For the starting material A, a metal frame 1 as shown in FIG.
After clamping with, the heating step is performed. In the heating step, for example, as shown in FIG. 2, heaters 2 and 3 are vertically introduced from the side of the starting material A as indicated by arrows a and b to heat the starting material A to soften it. In this heating step, the forming material A'is heated by the heaters 2 and 3 from both upper and lower sides to be softened. The heating conditions such as heating time and heating temperature are such that the starting material A droops excessively from the metal frame 1. It is set so that it can maintain a planar shape without being deformed and has an appropriate moldability required for molding to such an extent that it can be freely deformed. It is desirable that this heating step be completed in the shortest possible time so that the starting material A does not deteriorate. In that sense, it is advantageous to heat the starting material A from both upper and lower sides by the upper and lower heaters 2 and 3 because the entire thickness of the starting material A can be uniformly heated in a short time. In addition, the thicknesses of all layers of the starting material A are previously set to the heaters 2,
It is also useful to uniformly heat the entire thickness portion of the starting material A in a short time by raising the temperature uniformly to a temperature range lower than the temperature achieved by heating by.

Here, the starting material A includes a porous material originally having open cells, and of course, it can be expanded and transformed into a porous material having open cells by the above heating process. As long as it is a material, it is originally included even if it does not have open cells. Therefore,
If the starting material A is porous having open cells, the starting material A and the molding material A ′ are the same, and if the starting material A is a material having no open cells, the starting material A is
Becomes the same material as the above-mentioned molding material A'when it has open cells through the heating process.

A non-porous treatment step is performed on the molding material A'which has been softened through the heating step. In the non-perforating treatment step, the non-perforating sheet B clamped by the metal frame 4 as shown in FIG.
Is introduced from one side of the molding material A ′ to one surface side as indicated by an arrow c, and is overlapped. As the non-porous sheet B, a sheet having substantially no air circulation is used. That is, the non-perforated sheet B also includes a sheet having an air flowability but an extremely small amount such that the air flowability can be substantially ignored in the molding step described later. Further, it is desired that the non-perforated sheet B has extensibility and flexibility that can be freely deformed in the molding step described later. The extensibility and flexibility may be a property exhibited by the non-perforated sheet B at room temperature which is not heated, or a property exhibited by the non-perforated sheet B only after heating. The non-porous treatment step needs to be performed in a short time so as not to cause a situation in which the molding material A ′ is cooled and its flexibility is impaired. In some cases, the molding material A ′ is cured at ambient temperature. It is desirable to keep the temperature at a level that does not occur. The overlapping state of the molding material A ′ and the non-porous sheet B is such that even if the molding material A ′ and the non-porous sheet B are in contact and overlap with each other, the molding material A ′ and the non-porous sheet B are The and may be separated from each other and overlapped with each other.

A mold matching step is then performed on the molding material A'and the non-porous sheet B which have been layered on each other in the non-porous processing step. In the mold matching process, the lower table 5 as shown in FIG.
To align the mold 6 with the molding material A ',
This is a step of lowering the upper table 7 to align the compressed air box 8 with the non-perforated sheet B, and the like, and through this step, the molding material A ′ and the non-perforated sheet B become the mold 6 and the compressed air box. It is clamped by 8 and the inner space of the mold 6 and the compressed air box 8 is hermetically sealed. It is desired that this mold matching step is also performed in a short time so that the molding material A ′ is not cooled by the temperature decrease.

After performing the mold matching step, the molding step is performed. In the molding step, suction as shown by arrow d in FIG. 5 and pressurization by air pressure as shown by arrow e in FIG. 5 are performed. That is, suction is performed in the space facing the molding material A ′ (internal space of the mold 6) and compressed air is performed in the space facing the non-perforated sheet B (internal space of the compressed air box 8). Be seen. By doing so, the space facing the forming material A ′ has a negative pressure more than the space facing the non-porous sheet B. When the pressure difference between the two spaces is appropriately determined, the non-perforated sheet B is sucked toward the negative pressure side by the pressure difference and is deformed.
Due to such deformation of the non-perforated sheet B, the non-perforated sheet B presses the molding material A ′ toward the negative pressure side,
The molding material A ′ is deformed to the negative pressure side together with the non-perforated sheet B and comes into close contact with the molding surface 61 of the mold 6, and is deformed into a shape regulated by the shape of the molding surface 61. That is, the non-perforated sheet B apparently adsorbs to the molding material A ′ and follows the molding material A ′, and the molding material A ′ is pressed by the mold 6 due to the differential pressure.
Following the close contact with the molding surface 61, the non-perforated sheet B is transformed into a shape regulated by the molding material A ′. In this case, if the non-perforated sheet B has extensibility and flexibility,
The non-perforated sheet B is reasonably deformed so that the entire surface thereof surely follows the entire surface of the forming material A ′, which presses the entire forming material A ′ and surely follows the forming surface 61. Useful for that. Therefore, although the molding material A ′ itself is not sucked, the entire molding material A is surely brought into close contact with the molding surface 61 and molding is performed with high accuracy.

By the way, in the molding process, when only the molding material A'is installed between the mold 6 and the compressed air box 8 and the non-perforated sheet B is not installed, the internal space of the mold 6 is Even if the suction and the compressed air in the internal space of the compressed air box 6 are used together,
Since air flows through the open cells of the molding material A ′, the suction action and the compressed air action are not sufficiently applied to the molding material A ′.
However, when the non-perforated sheet B is installed, a suction action or a pneumatic action is applied to the non-perforated sheet B, the non-perforated sheet B is deformed toward the negative pressure side, and the non-perforated sheet B is pressed for molding. The material A'deforms toward the negative pressure side. Therefore, even though the molding material A ′ is an open-celled porous material, the vacuum compression molding of the molding material A ′ becomes possible.

The molding material A'which has undergone the molding process is cured by lowering the temperature and then taken out from the mold 6 together with the non-perforated sheet B as shown in FIG. And the formed molding material A '
By removing the non-perforated sheet B from the metal frames 1 and 4 and removing the unnecessary portions, the molded product A ″ shown in FIG. 7 is obtained. The non-perforated sheet B removed from the metal frame 4 is If it has extensibility and flexibility at room temperature, it can be reused to restore its original state.

In the molding method described above, before or during the molding step, the molding material A'is pressed by the plug 9 from the non-perforated sheet B side as shown in FIG. May be slightly deformed toward the negative pressure side in the molding process.
The deformation of the molding material A ′ and the non-porous sheet B in the molding process is assisted, and the uneven thickness of the obtained molded product A ″ is reduced.

Although the method according to the vacuum pressure forming method has been described above, the method of the present invention can also be applied to the vacuum forming method and the pressure forming method described at the beginning. That is, in the case of the vacuum forming method, after performing a non-pore forming treatment step on a forming material A'which is a sheet material softened by heating and made of a porous material having open cells, it is formed into a mold. Perform the installation process. Then, in the mold matching step, the molding material A ′ is exposed to the molding space of the mold. Following this mold matching step, the internal space of the mold facing the forming material A ′ is suctioned to a negative pressure. In this case, the space facing the non-perforated sheet B is open to the atmosphere. Further, in the case of the air pressure molding method, after performing a non-pore forming treatment step on a molding material A'which is a sheet material softened by heating and made of a porous material having open cells, it is formed into a mold. A mold matching step is performed so that the molding material A ′ faces the molding space of the mold, and air pressure is generated in the space facing the non-perforated sheet B. The space that the non-perforated sheet B faces is, for example, the internal space of the compressed air box 8 described above. In this way, when the space facing the molding material A ′ is made negative or air pressure is generated in the space facing the non-porous sheet B, the molding material A ′ is exposed to the space between both spaces. The space to be formed becomes a negative pressure relative to the space facing the non-perforated sheet B, and the non-perforated sheet B is deformed toward the negative pressure side due to the pressure difference between the two, and is pressed by the non-perforated sheet B. The material A'deforms toward the negative pressure side. Therefore, the molding material A ′ is molded along the molding surface of the mold into the same shape as that of the molding surface, as described in the above embodiment.

Next, an example in which a continuous cell green porous sheet material reinforced with a reinforcing fiber such as glass fiber is used as the molding material A'will be described.

The extruded sheet material or the pressed sheet material in which glass fiber is mixed in the synthetic resin layer does not have air bubbles inside and does not have air circulation even when it is softened by heating at room temperature. For conventional sheet materials, the conventional molding method described at the beginning can be applied as it is. Therefore, even a sheet material reinforced with reinforcing fibers, which does not have air circulation, is excluded from the object to be used in the method of the present invention. The sheet material used in the method of the present invention is a sheet material having open cells communicating with both front and back surfaces, and the air bubbles are exhibited by the open cells, and the open cells included in the sheet material are the sheet material. The open cells may be provided during the production of the above, or the open cells may be provided by expanding the non-porous sheet material through the heating process described above.

By the way, as the above-mentioned starting material A in the form of a sheet having no open cells, there is a sheet material manufactured by the method described in JP-A-60-158227. The sheet material produced by the method described in this publication contains glass monofilaments as reinforcing monofilaments in a uniform density throughout the sheet material. The manufacturing method described in this publication is the method described below. That is, a powdered or granular thermoplastic resin, glass single fibers, a foaming agent, and water are mixed to prepare a foaming dispersion liquid in which fine bubbles are dispersed, and the foaming dispersion liquid is used in the papermaking field. A sheet obtained by making a sheet on a porous support such as a net and dehydrating it in the same manner as making a sheet, and drying the obtained sheet, and then continuously heat-solidifying the glass single fibers to disperse the glass single fibers in a uniform density throughout. It is a method of obtaining (original material).

When the above-mentioned raw fabric is heated in the heating step described with reference to FIG. 2, the glass single fiber is restored to some extent by the stress accumulated in the glass single fiber at the time of thermal compression solidification during production, and the force causes the resin of the raw fabric to be restored. The layer apparently expands to form open cells in the resin layer. The porous material having open cells thus obtained is suitable for use as the above-mentioned molding material A ′. Then, the formed continuous cells remain after molding.

As the synthetic resin used for the above-mentioned fabric, there are thermoplastic resins such as polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycarbonate (PC) and nylon. Yes, among them PP and PE
Can be preferably used. Further, instead of the glass single fiber, it is possible to use carbon fibers, metal fibers, and other fibers useful for reinforcement. When using glass monofilaments, 2 monofilaments with a thickness of 5 to 20 μm and a length of 7 to 50 mm are used.
If the balance is 5 to 40% by weight and the balance is a thermoplastic resin, the glass monofilaments are uniformly wrapped around the entire resin layer by the recompression at the time of expansion molding described above, and the reinforcing effect and abrasion resistance by the glass monofilaments are exerted. Evenly spread over the entire sheet material.

A porous material obtained by expanding and molding the above-mentioned raw material according to JP-A-60-179234 is used as a molding material A '.
Can also be used as This expansion molding is a method in which an original fabric is heated and expanded to form continuous cells, and then compressed again to obtain a sheet body thicker than the original fabric. The continuous cells remain even after the original fabric is cured.

A KP sheet (trade name) manufactured by Cape La Sheet Co., Ltd. is available as a sheet material corresponding to the above-mentioned original fabric. This is a sheet material having a thickness of about 0.5 to 5 mm containing 70% by weight of PP and 30% by weight of glass single fiber. When this KP sheet is transformed into the molding material A ′ (that is, transformed from a non-porous sheet into a porous sheet having open cells) and the method of the present invention is applied, the resin is recovered by the restoring force of the glass single fiber in the above heating step. It is advisable to expand the layer 2 to 4 times. If the expansion coefficient is out of this range, there may be insufficient open cells or insufficient strength. Further, the KP sheet remains in the sheet shape even when heated to 200 ° C. in the heating step. Therefore, 200 ℃
That is, it is possible to heat at a high temperature, thereby satisfying the sufficient flexibility and fluidity required for the molding material A ′ in the molding process. It is considered that the KP sheet can maintain the sheet shape at a high temperature of 200 ° C. because the glass single fibers have a sufficient role of retaining the shape of the softened synthetic resin layer. In this regard, if the content of the glass single fibers is too low, the sheet shape may not be maintained at a high temperature of 200 ° C due to insufficient strength. results of the experiment,
When the heating temperature is 170 to 230 ° C., sufficient flexibility and fluidity required for the molding material A ′ are satisfied in the molding step, and particularly when heated in the range of 190 to 210 ° C., it can be molded into a considerably complicated shape. Have confirmed. Heating temperature is 1
If the temperature is lower than 70 ° C., the KP sheet is hard to be uniformly heated over the entire layer thickness portion in a short time, and therefore the fluidity is insufficient and the glass single fibers are unevenly distributed in the molded article.
It may be difficult to obtain uniform strength in each part. Also,
If the heating temperature is higher than 230 ° C., the phenomenon that smoke is emitted from the KP sheet appears, and the hue tends to deteriorate due to heat deterioration or surface burning. The smoke is considered to be due to overheating of the additive.

The non-porous sheet B for non-porous treatment of the molding material A'obtained by expanding the KP sheet is extremely heated at the molding temperature of the molding material A'formed through the heating process. It is required that it does not deteriorate. And as mentioned above, it is desirable that the non-perforated sheet B has extensibility and flexibility. In this case, the non-porous sheet B satisfying the required heat resistance, extensibility and flexibility includes silicon rubber, butadiene rubber, nitrile rubber, urethane rubber and the like. The flexibility and extensibility of the non-porous sheet B include not only the flexibility and extensibility at room temperature but also the flexibility and extensibility exhibited by heating to a predetermined temperature. There is typically polyethylene terephthalate (PET) resin as such a material.
However, like PET, which exhibits extensibility by heating and whose extensibility is not reversible (that is, which does not have elasticity), is forced to be disposable only once. On the other hand, the above-mentioned silicone rubber, butadiene rubber, nitrile rubber, urethane rubber, etc. have the advantage that they can be reused several times because they have elasticity at room temperature. The non-perforated sheet B needs to have a thickness that does not impair its flexibility and extensibility, and is 0.5 to 0.5 for silicon rubber, butadiene rubber, nitrile rubber, urethane rubber, etc. Those having a thickness of 5 mm can be suitably used.

In the molding process, the pressure difference between the space facing the molding material A'and the space facing the non-perforated sheet B depends on how easily the molding material A'and the non-perforated sheet B are deformed. It is necessary to appropriately determine whether there is any. KP when the seat was expanded using a molding material A 'and imperforate sheets B thus obtained, 4~7kg / cm ² in vacuum pressure forming, 1 kg / cm ² in vacuum forming (substantially from 0.85 to 0.9 kg
/ Cm ² ), it is desired to set 3 to 6 kg / cm ² by pressure molding, and if the differential pressure is too large or too small, the material A ′ for molding cannot be molded properly. obtain.

The molded product A "formed by expanding the KP sheet is excellent in water resistance and light weight. Further, its flexibility and rigidity are used by appropriately selecting the compounding ratio of the glass single fiber and the synthetic resin. Therefore, it is a material suitable for a concrete formwork, a core material for a backrest of a chair or a seat, etc. Therefore, the present invention provides an open-celled porous sheet material. Is used as a molding material A ', and it is particularly preferably used when it is molded into a shape suitable for the concrete formwork or the core material for a chair.

By the way, since the above KP sheet contains glass single fibers, the glass single fibers may be exposed and fluffed on the surface depending on the content of the glass single fibers. Therefore, the fluff of the glass monofilaments may remain as it is in the molded product A "produced by molding the molding material A'obtained by expanding the KP sheet. As for the above, there is a troublesome handling such that the fluffed glass monofilament gets stuck in the skin of the operator and itches. In order to avoid such a situation as much as possible, it is effective to suppress the fluffing of the glass single fibers by laminating and integrating an outer cover such as cloth on the surface of the molding material A ′. In that case, before the non-perforating treatment of the molding material A ′ with the non-perforating sheet B, an outer cover is placed on one surface of the molding material A ′, and the non-perforating treatment is applied to such molding material A ′. Good to do. By doing so, by performing a molding process as a post-process, the outer cover adheres to the resin layer of the molding material A ′, the glass single fibers are pressed by the outer cover, and fluffing on the surface is suppressed. It is easy to handle. The outer skin is a heat-sensitive adhesive and is a molding material A '.
It may be attached to.

In addition to the above-mentioned cloth, the outer skin includes net, leather, P
A foam material having a cushioning function such as a VC / PP foam or a PVC / nylon foam, a fabric or the like can be preferably used. When an outer skin that does not have air circulation is used, the non-perforated sheet B can also serve as such an outer skin that does not have air circulation, and in that case, the outer skin is decorated. It is desirable to improve the surface mounting of the molded product A by using a material having properties such as properties.

[0030]

According to the present invention, it is possible to apply the vacuum forming method, the pressure forming method, and the vacuum pressure forming method using the open-cell porous sheet material as a forming material. for that reason,
There is an effect that the multi-product small-quantity production method, which is an advantage of those forming methods, can be applied to the open-cell porous sheet material.

[Brief description of drawings]

FIG. 1 is an explanatory view of a state where a molding material is clamped.

FIG. 2 is an explanatory diagram of a heating process.

FIG. 3 is an explanatory diagram of a non-hole forming process.

FIG. 4 is an explanatory diagram of a mold matching process.

FIG. 5 is an explanatory diagram of a molding process.

FIG. 6 is an explanatory diagram showing a released state.

FIG. 7 is an explanatory diagram of a molded product.

FIG. 8 is an explanatory view showing a state in which a molding material is pressed by a plug.

[Explanation of symbols]

 A'Molding material B Non-perforated sheet 6 type

Claims (1)

Claim: What is claimed is: 1. A non-porous treatment step of stacking a non-porous sheet on one side of a molding material made of a porous material having open cells, which is softened by heating, and non-porous. After the mold matching process, the molding material and the non-porous sheet that have undergone the treatment process are installed in the mold, and after the mold matching step, the space facing the molding material is set to a negative pressure more than that of the space facing the non-porous sheet. A method for forming an open-celled porous sheet material, comprising: a step of deforming the perforated sheet to the negative pressure side and pressing the forming material against the forming surface of the mold with the non-perforated sheet.