JP2000006174A - Laminated molding and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for easily manufacturing a laminated molding having no or extremely little warp deformation according to an integrating lamination of sheets made of first thermoplastic resin by laminating the sheets on a base material made of a second thermoplastic resin. SOLUTION: The method for manufacturing a laminated molding obtained by integrally laminating a second thermoplastic resin of a melted state with a sheet made of a first thermoplastic resin in a mold comprises a step of supplying the sheet made of the first resin between molding surfaces of both the molds 3, 4, a step of supplying the second resin of a melted state between the sheet and the molding surface of the one mold 4, a step of integrating the second resin with the sheet made of the first resin, a step of holding a pressure applied to the integrated molding in a range of 0 to 1 MPa, a step of pressurizing the pressure applied to the integrated molding at the held pressure or more, and a step of cooling the molding while maintaining the pressurized state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminate formed of a thermoplastic resin and a method for producing the same.

[0002]

2. Description of the Related Art Hitherto, a laminated molded article in which a sheet or film made of a thermoplastic resin is integrally laminated as a surface layer on a core material layer made of a thermoplastic resin is well known, and there are well known automobile interior parts and parts. Used for home appliance parts and the like.

[0003] As a method of manufacturing such a laminated molded article,
For example, as disclosed in Japanese Patent Publication No. 3-33492, a sheet or film is previously set in a mold, and the molten thermoplastic resin supplied into the mold is shaped and a sheet is formed on the surface at the same time. A method of fusing and integrating a film and a film is known.

However, according to such a method,
For example, when a cushioning material or a sheet having a relatively low tensile modulus of the material is bonded as a skin material, the obtained laminated molded article has little deformation, but has a relatively high modulus of elasticity.
When a resin sheet generally called a hard sheet is stuck, there is a problem that warpage is likely to occur.

[0005]

SUMMARY OF THE INVENTION
The present inventors have studied a method of easily manufacturing a laminated molded body in which warpage does not easily occur during molding even when a resin sheet called a hard sheet having a relatively high elastic modulus is used. The present invention has been reached.

[0006]

That is, the present invention uses a pair of male and female molds for forming a desired cavity, and forms a second molten resin on a sheet made of a first thermoplastic resin.
A method for producing a laminated molded article obtained by laminating and integrating a thermoplastic resin in a mold, comprising: (a) supplying a sheet made of a first thermoplastic resin between molding surfaces of both molds; (B) supplying a molten second thermoplastic resin between the sheet and a molding surface of one of the molds; (c) filling the molten second thermoplastic resin into a mold cavity; Integrating a second thermoplastic resin into a sheet made of the first thermoplastic resin,
(D) a step of maintaining the pressure applied to the sheet made of the first thermoplastic resin and the second thermoplastic resin in the range of 0 to 1 MPa; (D) the pressure applied to the sheet and the second thermoplastic resin.
And (f) a step of cooling while maintaining the pressurized state, and a method for producing a laminated molded article, which is provided by the method. To provide a laminated molded article.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The laminated molded article of the present invention uses a pair of male and female molds for forming a desired cavity, and is formed of a first thermoplastic resin by a method of the present invention described later.
The second thermoplastic resin in a molten state is laminated and integrated in a mold in a mold. The first thermoplastic resin sheet is used as a skin material, and the second thermoplastic resin is used as a core material. It has an integrated structure. The shape, size, thickness, and the like of such a laminated molded article vary depending on the application, but deformation is more problematic for wall panels, floor materials, ceiling materials, desk top plates, storage panels, doors, This is a case where the laminate has a relatively planar shape such as a decorative panel or a signboard, and the laminated molded article of the present invention is suitable as a laminated molded article having such a planar shape.

In the laminated molded article of the present invention, even if such a surface has a shape close to a flat surface, it is not necessary that the back surface side be a flat surface. May be provided integrally.

[0009] As described above, the laminated molded article of the present invention is formed by melting the second thermoplastic resin sheet (1) in the molten state.
It is manufactured by laminating and integrating the thermoplastic resin (2) in a mold. The sheet made of the first thermoplastic resin, which is one of the raw materials, has functions such as design, durability and impact resistance. In many cases, the surface imparts properties, and a material more suitable for use as a laminated molded product is selected and used. For example, in the case of an application in which design is emphasized, a monochromatic or stone-grained colored material may be used, or the back surface may be seen through depending on the type of the second thermoplastic resin serving as the base material. In such cases, a transparent or translucent sheet may be used, and furthermore, some or all of the sheet may be printed,
A design or the like imitating fine irregularities or tile joints may be given.

According to the performance required of the product, for example, when the surface is required to have scratch resistance or surface hardness, a sheet made of a material having high hardness such as an acrylic resin may be used. In order to prevent this, a sheet having high gas barrier properties can be used, and in addition, an anti-fog sheet, a sheet provided with antibacterial and antifungal properties, a visibility control sheet
Can be used. In addition, a soft sheet such as a soft polyolefin can be used to obtain a soft feel.

The thickness of the sheet made of the first thermoplastic resin is generally about 50 μm to 3 mm, and is specifically selected according to the intended use.
When the sheet itself is used for the purpose of improving the surface properties such as surface decoration and surface hardness, a relatively thin sheet having a thickness of about 50 μm to 500 μm may be used. When using a translucent sheet, 100 μm or more
A sheet having a thickness of about 300 μm is preferably used. These sheets may be a single layer or a multilayer sheet composed of the same or different materials.

[0012] A sheath made of such a first thermoplastic resin.
The first thermoplastic resin is manufactured by a conventional method, for example, a continuous extrusion molding method in which both surfaces of a sheet are cooled by a roll represented by a T-die or a calendar extrusion molding method to form a film. The production method is not limited at all.

In general, a thermoplastic resin sheet produced by extrusion molding or the like undergoes heat shrinkage due to molecular orientation due to stretching during processing, but the heat shrinkage rate depends on the sheet molding conditions and raw material resin. Depending on the direction of the sheet. For this reason, in the production method of the present invention, when the sheet made of the first thermoplastic resin is disposed between the molds, the directionality of the heat shrinkage is considered,
For example, when the surface shape is a square or a circle or a shape close to these, a sheet having a relatively small directionality is used, and when the surface shape is a rectangle or the like having a high aspect ratio, a direction having a large shrinkage is used. May be arranged in the longitudinal direction of the molded body.

In the sheet made of the first thermoplastic resin, if the heat shrinkage of the sheet is too high, the obtained molded article is likely to be warped, and if the heat shrinkage is too low, the sheet is in the opposite direction to the above. Since warpage is likely to occur, the heat shrinkage ratio is 0.1
It is preferred to use sheets in the range of -20%, especially 0.5-5%. Incidentally, the heat shrinkage rate here is calculated based on a measured value at 100 ° C. when the thermoplastic resin deformation temperature of the first thermoplastic resin as the sheet raw material or the heat deformation temperature is less than 100 ° C. The thermal deformation temperature (deflection temperature under load) is a temperature measured based on ASTM D-648. When the heat deformation temperature is set, when the sheet is a multilayer sheet composed of two or more layers, the heat deformation temperature of the material resin having the larger thickness may be used as a reference, and the thicknesses are almost equal. In the case of (1), the higher of the heat deformation temperature of the material resin may be used as a reference.

In the method of the present invention, the second thermoplastic resin supplied between the molds in a molten state as the other raw material may serve as a structural material (substrate) mainly responsible for the strength of the molded body. In many cases, when the sheet is combined with a sheet made of a transparent or translucent first thermoplastic resin, the joining surface between the second thermoplastic resin and the sheet material is seen through. In some cases, the thermoplastic resin is responsible for the design.

The first thermoplastic resin serving as the sheet material and the second thermoplastic resin supplied between the molds in a molten state and constituting the base material of the molded article are polyethylene, polypropylene and PET, respectively. Acrylonitrile styrene copolymer (AS resin), acrylonitrile butadiene styrene terpolymer (ABS resin), polystyrene (PS resin), styrene / methyl methacrylate copolymer (MS resin), polycarbonate ( (PC resin), thermoplastic resins such as polyamides, and polymer alloys composed of these.

[0017] Such a thermoplastic resin may contain various additives which are usually blended, and if necessary, a filler such as talc or fiber may be blended, or an organic or inorganic foam may be added. An agent may be blended. Also,
When it is desired to impart flexibility, a known soft material such as a polypropylene block copolymer as disclosed in JP-A-9-32022 can be used. The combination of the first thermoplastic resin and the second thermoplastic resin is appropriately selected depending on the application, and the two resins may be the same or different, but can be easily bonded to each other by heat fusion or the like. It is preferable to select

The thermoplastic resin generally has a property of causing a dimensional change due to a temperature change, and its linear expansion coefficient value is 4 ×
The first thermoplastic resin and the second thermoplastic resin having a linear expansion coefficient of about 10 ⁻⁵ to 10 × 10 ⁻⁵ (cm / cm / ° C.)
When a thermoplastic resin is used in combination, the resulting laminate may undergo large warpage deformation due to a temperature change or crack due to internal stress. It is preferable to select a combination that falls within the range of 2 to 2.

Next, a method for producing such a laminated molded article will be described. In the method of the present invention, a pair of male and female molds (3, 4) having a cavity for forming a desired product shape is used as illustrated in FIG. This mold is attached to the mold clamping device so that it can be opened and closed,
Normally, one of the male and female molds is fixed, and the other mold is movable. In the mold illustrated in FIG. 1, a male mold (4) is fixed, and a female mold (3) is movable.

The molding surface of the mold (male mold in the figure) on the side of the two molds which is in contact with the second thermoplastic resin is for supplying the molten second thermoplastic resin into the cavity. A molten resin supply port (5) is provided. The molten resin supply port is connected to an in-line type injection machine or the like (not shown) through a molten resin passage (6) to supply the second thermoplastic resin melted by the injection machine into the cavity. Is available.

The mold temperature is appropriately determined depending on the types of the first thermoplastic resin and the second thermoplastic resin to be used.
Generally, the temperature is set lower than the melting temperature or heat deformation temperature of the resin used. For this reason, a pipe such as a water pipe is provided in the mold, and an appropriate medium such as water, hot water, steam or oil flows in the pipe, so that the mold temperature can be arbitrarily adjusted. .

The sheet made of the first thermoplastic resin, which is one raw material of the present invention, is supplied between the male and female molds in an open state. (FIG. 2) As a supply method, the mold may be directly mounted on the molding surface of one mold, for example, a male mold, or may be fixed on the molding surface of one mold. It is preferable to fix the second thermoplastic resin on the mold surface so as not to be displaced during the molding process, or to be stretched or wrinkled when the second thermoplastic resin in the molten state supplied thereafter flows through the cavity. The means for fixing the sheet is optional, but a method capable of fixing the sheet in a short time, such as suctioning the sheet by vacuum suction from a suction hole provided on the forming surface, is preferable.

After a sheet made of the first thermoplastic resin is supplied between the molds, a second thermoplastic resin in a molten state is supplied between the sheet and the molding surface of the mold. (2) Filling the cavity with the thermoplastic resin, the sheet made of the first thermoplastic resin and the second thermoplastic resin are integrated. The second thermoplastic resin in a molten state is supplied, the second thermoplastic resin is filled in the cavity, and a sheath made of the first thermoplastic resin is supplied.
The following two methods are typically given as a method for integrating the second thermoplastic resin with the second thermoplastic resin.

The first method is an injection molding type method. In this method, after a sheet made of the first thermoplastic resin is supplied between the molds, the molds are closed and the space between the molding surfaces of both molds is closed. The two dies are held so that the distance (cavity clearance) becomes equal to the thickness of the final molded body (FIG. 8), and the second thermoplastic resin in a molten state is injected into the closed cavity from the resin supply port under high pressure. This is a method of injecting (FIG. 9) and filling the cavity with the second thermoplastic resin in a molten state (FIG. 10).

The second method is a compression molding type or an injection compression molding type. In this method, after a sheet made of the first thermoplastic resin is supplied between the molds, the sheet thickness is reduced by the thickness of the final molded body. A second thermoplastic resin in a molten state is supplied from the resin supply port between the two dies with a large cavity clearance (unclosed state) (FIG. 3), and substantially simultaneously with the completion of the supply of the molten resin or the supply of the molten resin. Before the completion, the movable resin (female mold in the figure) is moved and approached to spread the molten resin into the cavity, and finally moved and approached (clamped) until the cavity clearance reaches the thickness of the final molded body. This is a method of filling the cavity with a second thermoplastic resin in a molten state (FIG. 4).

In the case of the first method, the second thermoplastic resin of the molten resin is subjected to a high pressure enough to fill the closed cavity with the resin by the supply pressure. In the case of using the method of
The thermoplastic resin is under a relatively low pressure due to the mold clamping pressure.

Another method for filling the cavity with the molten second thermoplastic resin is to mold the molten second thermoplastic resin extruded by an extruder or the like by an external supply means such as a supply arm or the like. A method of supplying onto a molding surface from the outside, a method of heating and melting a second thermoplastic resin previously processed into a sheet and supplying the same to the molding surface, and the like, are mentioned in the method of the present invention. The above-described second method is most preferable in terms of workability, pressure applied to the resin, and the like.

In the method of supplying the second thermoplastic resin in a molten state in a state in which both molds are not closed as represented by the second method, the second thermoplastic resin in the molten state is started after mold clamping is started. The mold clamping operation may be temporarily stopped at a predetermined cavity clearance while supplying the resin, or the mold clamping operation and the supply of the resin may be performed in parallel. The cavity clearance when supplying the second thermoplastic resin in the molten state is appropriately selected depending on the desired thickness of the final product, the material to be used, the temperature conditions, and the like. Generally, the thickness of the final product plus 0.5 is used. It is about 50 mm.

The amount of the resin to be supplied is appropriately determined according to the volume of the final product, and the supply temperature is also appropriately determined according to the type of the first thermoplastic resin sheet and the type of the second thermoplastic resin supplied earlier. It is determined. As a general tendency, as the supply temperature of the second thermoplastic resin in the molten state becomes lower,
The damage given to the sheet made of the first thermoplastic resin becomes small, and the above-mentioned molding shrinkage becomes slightly small.

The cavity is filled with the molten second thermoplastic resin by an appropriate method as described above, and after the sheet made of the first thermoplastic resin is integrated with the second thermoplastic resin, By reducing the mold clamping force of both molds or by applying a force in the mold opening direction, the pressure applied to the sheet made of the first thermoplastic resin in the pressurized state and the second thermoplastic resin in the molten state Reduce. (Fig. 5)

The second molten state filled in the cavity
The heat of the thermoplastic resin is radiated from the molding surface of the other mold via the molding surface of the mold in direct contact therewith and the sheet made of the integrated first thermoplastic resin. At this time, the temperature of the sheet made of the first thermoplastic resin increases due to the heat of the second thermoplastic resin, and the sheet tends to shrink. However, when cooling is started in this state, the sheet becomes Since it is in a pressurized state, it is cooled while its shrinkage is hindered.
In this case, there is a dimensional difference between the sheet made of the second thermoplastic resin and the first thermoplastic resin accompanied by molding shrinkage, and the sheet is deformed so as to be convex.

However, as in the method of the present invention, the mold clamping force of both molds is reduced or a force in the mold opening direction is applied to make the sheet made of the first thermoplastic resin in a pressurized state. By reducing the pressure applied to the second thermoplastic resin and the pressure applied to the sheet made of the first thermoplastic resin whose temperature has been increased by the heat received from the second thermoplastic resin, the sheet becomes A force can be generated in the direction of contraction by the heat, and the dimensional difference between the sheet made of the second thermoplastic resin and the sheet made of the first thermoplastic resin is reduced, so that the deformation of the product can be reduced. Reduce the mold clamping force at this time,
Alternatively, the pressure applied to the sheet made of the first thermoplastic resin and the second thermoplastic resin by applying a force in the mold opening direction is generally in the range of about 0 to 1 MPa, but more shrinkage is desired. Occasionally, both dies can be opened until a slight gap (7) is formed between the sheet and the mold forming surface.

When the pressure applied to the sheet made of the first thermoplastic resin and the pressure applied to the second thermoplastic resin are reduced, the temperature of the second thermoplastic resin in the molten state is at least the sheet made of the first thermoplastic resin. The temperature of the surface in contact with the first thermoplastic resin must be desirably higher than the thermal deformation temperature of the first thermoplastic resin by about 10 to 100 ° C. If the temperature is too low, the temperature of the sheet will not be sufficiently high and the bonding will be insufficient. If the temperature is too high, the temperature of the sheet will be too high and will melt. On the other hand, the temperature of the sheet made of the first thermoplastic resin obtained from the second thermoplastic resin in the molten state is gradually increased, and the sheet tends to shrink. At this time, although the temperature of the sheet is distributed in the thickness direction, at least 50% or more of the sheet thickness, particularly 80% or more of the sheet thickness, and further, the entire sheet is made of the first thermoplastic resin. It is desirable that the temperature be equal to or higher than the heat distortion temperature of the resin, particularly in the range of 10 to 100 ° C. If the thickness of the sheet is too large, it takes time to raise the temperature, or it is difficult to raise the temperature to a temperature higher than the heat deformation temperature. Thus, about 50 μm to 3 mm is suitable.

The pressure applied to the sheet made of the first thermoplastic resin and the second thermoplastic resin is kept within the above-mentioned range, and the sheet temperature reaches the above-mentioned desired temperature, and the sheet shrinks. For example, both molds are clamped (FIG. 6), and the molten resin and the sheet are cooled while maintaining the pressurized state by the mold clamping.
The pressing force at this time varies depending on the contraction rate of the material to be used, etc., but needs to be higher than the pressing force in the previous step, and is usually about 1 to 20 MPa, preferably 5 to 10 M
It is about Pa.

After cooling to the temperature at which the product is taken out, both molds are opened, and the solidified compact is taken out. (FIG. 7) As a result, it is possible to obtain a laminate formed by laminating the sheet made of the first thermoplastic resin on the base resin layer made of the second thermoplastic resin as shown in FIG. FIG.
In the case of obtaining a laminated molded body having a rib (8) or the like in the base portion as shown in 2, a groove or a concave portion may be provided in advance on a molding surface of a die to be used.

In the sheet made of the first thermoplastic resin used in the present invention, it is desirable that the ideal heat shrinkage of the sheet is equal to the molding shrinkage of the molded article taken out. Generally, if the molding shrinkage of the second thermoplastic resin is equal to or greater than the molding shrinkage, no large deformation occurs.

According to such a method, the sheet made of the first thermoplastic resin is laminated on the base material made of the second thermoplastic resin, and further, there is no warping deformation due to the integrated lamination of the sheet or no warping deformation. Very few laminated molded articles can be easily obtained. The thus obtained laminated molded body without deformation is widely used as panels for walls, ceilings, floors, etc., kitchen equipment, doors, wash basins, housing equipment and interior and exterior materials for automobiles.

For example, in the case of a laminated molded article for a wall panel,
When an acrylic resin (first thermoplastic resin) sheet is used and an ABS resin is used as the core resin (second thermoplastic resin), the molding shrinkage of the ABS resin is usually 0.4 to less.
Since it is about 0.6%, an acrylic resin having a heat deformation temperature of about 100 ° C. and a heat shrinkage of the same or about several percent may be used. The temperature of the ABS resin in the molten state when reducing the pressure applied to the sheet made of the acrylic resin and the ABS resin in the molten state is in the range of about 110 to 200 ° C. The sheet temperature of the sheet is 1 on the side in contact with the molding surface of the sheet.
It is desirable that the temperature be 00 ° C. or higher.

[0039]

The sheet made of the first thermoplastic resin is laminated on the base material made of the second thermoplastic resin, and furthermore, there is no warpage deformation due to the integrated lamination of the sheet or very little lamination deformation. The body can be obtained easily.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a mold used in the method of the present invention.

FIG. 2 is a schematic sectional view of a mold apparatus showing a manufacturing process in the method of the present invention.

FIG. 3 is a schematic sectional view of a mold apparatus showing a manufacturing process in the method of the present invention.

FIG. 4 is a schematic sectional view of a mold apparatus showing a manufacturing process in the method of the present invention.

FIG. 5 is a schematic sectional view of a mold apparatus showing a manufacturing process in the method of the present invention.

FIG. 6 is a schematic sectional view of a mold apparatus showing a manufacturing process in the method of the present invention.

FIG. 7 is a schematic sectional view of a mold apparatus showing a manufacturing process in the method of the present invention.

FIG. 8 is a schematic sectional view of a mold apparatus showing a manufacturing process in the method of the present invention.

FIG. 9 is a schematic sectional view of a mold apparatus showing a manufacturing process in the method of the present invention.

FIG. 10 is a schematic sectional view of a mold apparatus showing a manufacturing process in the method of the present invention.

FIG. 11 is a cross-sectional view showing an example of a laminated molded article obtained by the method of the present invention.

FIG. 12 is a cross-sectional view showing an example of a laminated molded product obtained by the method of the present invention.

[Explanation of symbols]

 1: Sheet made of first thermoplastic resin 2: Second thermoplastic resin 3: Female mold 4: Male mold 5: Molten resin supply port 6: Molten resin passage 7: Void 8: Rib

Claims (7)

[Claims] 1. A mold comprising a pair of male and female forming a desired cavity, wherein a second thermoplastic resin in a molten state is laminated and integrated in a mold on a sheet made of a first thermoplastic resin. A method for producing a laminated molded article, comprising: (a) a step of supplying a sheet made of a first thermoplastic resin between molding surfaces of both molds; (b) molding of the sheet and one of the molds Supplying a second thermoplastic resin in a molten state between the surfaces; (c) filling the second thermoplastic resin in the molten state into a mold cavity;
(D) a step of integrating the second thermoplastic resin with the sheet of the thermoplastic resin, and (d) reducing the pressure applied to the integrated sheet of the first thermoplastic resin and the second thermoplastic resin to 0 to 1M.
(E) a step of applying a pressure applied to the integrated sheet of the first thermoplastic resin and the second thermoplastic resin to a pressure equal to or higher than the pressure held in the step (d);
(F) A method for producing a laminated molded article, comprising a step of cooling while maintaining a pressurized state. 2. The laminate according to claim 1, wherein the temperature of the molten second thermoplastic resin supplied into the mold is equal to or higher than the thermal deformation temperature of the first thermoplastic resin forming the sheet. A method for producing a molded article. 3. The step (d), wherein the temperature of the second thermoplastic resin at the contact surface with the sheet made of the first thermoplastic resin is higher than the thermal deformation temperature of the first thermoplastic resin.
3. The method for producing a laminated molded article according to 1. 4. The pressure applied in the step (e) is 1 to 20 MPa.
The method for producing a laminated molded article according to claim 1, which is a. 5. The lamination molding according to claim 1, wherein in the step (d), at least 50% or more of the thickness of the sheet made of the first thermoplastic resin is not less than the thermal deformation temperature of the first thermoplastic resin. How to make the body. 6. The method according to claim 1, wherein the heat shrinkage of the sheet made of the first thermoplastic resin is equal to or higher than the molding shrinkage of the second thermoplastic resin. 7. A mold comprising a pair of male and female members forming a desired cavity, wherein a second thermoplastic resin in a molten state is integrally laminated on a sheet made of a first thermoplastic resin in the mold by the following steps. A laminated molded article characterized by being formed into a laminate. (A) a step of supplying a sheet made of the first thermoplastic resin between the molding surfaces of both molds; (b) a second thermoplastic resin in a molten state between the sheet and the molding surface of one mold; Supplying resin,
(C) filling the second thermoplastic resin in the molten state into a mold cavity, and integrating the second thermoplastic resin into a sheet made of the first thermoplastic resin; First
A step of maintaining the pressure applied to the sheet made of the thermoplastic resin and the second thermoplastic resin in the range of 0 to 1 MPa; (e) the sheet made of the integrated first thermoplastic resin and the second thermoplastic resin A step of increasing the pressure applied to the resin to a pressure equal to or higher than the pressure held in the step (d), and (f) a step of cooling while maintaining the pressure state