JPH0620768B2 - One-piece molding method for decorative molded products - Google Patents

Description

TECHNICAL FIELD The present invention relates to integral molding of a decorative molded product. More specifically, the present invention relates to the integral molding of a decorative molded product, which has a soft textured appearance, a soft cushioned feel, and a large-sized molded product with good adhesiveness.

[Conventional technology]

In recent years, molding materials made of thermoplastic resins such as polypropylene and acrylonitrile-butadiene-styrene copolymer (ABS resin) have been used as a base material for interior parts such as instrument panels of automobile door trims, and the appearance and soft appearance In order to impart a nice touch, a sheet-shaped multilayer material formed by laminating a fabric-based fabric layer such as a woven or knitted fabric and a synthetic resin foam layer such as a polyolefin-based resin is attached to the surface of the molding substrate. Many combined decorative molded products are manufactured.

Conventionally, as a method for producing such a decorative molded article, a method of sticking the sheet-shaped multilayer material to a surface of a base material previously molded into a desired shape in a post-process, or a sheet-shaped preliminarily sealed mold. A method of inserting a multi-layer material and simultaneously integrally molding it with a base resin by injection molding, or heating and softening a laminated sheet in which a base material and a sheet-shaped multi-layer material are adhered in advance and then press-molding to obtain a desired shape. A method for obtaining a decorative molded article is generally known.

However, according to these methods, on the one hand, the product appearance can be finished with good quality, but on the other hand, the manufacturing man-hours, equipment cost, material loss, etc. required for applying the adhesive or adhering the sheet-shaped multilayer material are excessive. There is a problem of production cost related to.

In order to solve these problems, a resin compression molding method has recently attracted attention as a new method for manufacturing the decorative molded article instead of the above method. The essence of the method is that a sheet-shaped multi-layered material having a polyolefin resin foam layer is located on one surface of a pair of molding dies opened opposite to each other, and a molten resin as a base material on the other mold surface. After placing a required amount of the sheet-shaped multi-layered material on the back surface of the sheet-shaped multi-layered material, the base resin is heat-sealed to the sheet-shaped multi-layered material while the molding die is engaged and compressed by the mold clamping force. This is a method of integrally molding a material and a base material into a desired shape at the same time. JP-A-62-181113 is known as a molding method having a film between a base material and a foam layer.

When a fabric layer having a raised fabric is used, the foaming layer directly fused to the base material is crushed to cause a decrease in cushioning property, though not so much as in the conventional injection insert molding. In many cases, the quality of the appearance is impaired due to shrinkage and the like, and a high quality product cannot be obtained.

Therefore, in producing the decorative molded article using a fabric layer having a raised fabric, prior to the present invention, there is no hair collapse of the fabric layer, shrinkage of the pile, etc. A method for producing a decorative molded article has been found and filed in JP-A-64-63111 and is publicly known. The gist of the invention of this prior application is that in the resin compression molding method already described, the temperature of the upper mold on the side in contact with the fabric layer is 10 ° C. or lower, and the temperature of the lower mold on which the base resin is placed is 10 to 10. This is a method for integrally molding a decorative molded article, which is characterized by holding at 25 ° C. and reducing the holding pressure after mold clamping to a low pressure of 30 kg / cm ² or less.

This is a method of compression molding under a specific molding condition consisting of a low temperature setting and a holding pressure, and this method has achieved an improvement effect that the appearance of the fabric layer after molding is dramatically improved. Keeping the temperature of the upper mold at 10 ° C. or lower by this method means that the temperature becomes equal to or lower than the dew point temperature of air around the mold in a normal environment, and as a result, water drops or water on the surface of the upper mold. The film adhered over the entire surface. Therefore, during molding, the cloth layer is in close contact with the upper mold surface, so that the cloth layer surface is wetted by the water droplets or water film, and this wetting phenomenon promotes cooling of the cloth layer. In addition, the temperature rise of the foam layer on the back side of the fabric layer is also hindered thereby, effectively acting in the direction of cooling and hardening,
It was confirmed that it contributes to the appearance of the fabric layer after molding and elasticity retention of the foam layer.

[Problems to be solved by the invention]

However, if the mold is cooled too much, moisture in the air will adhere to the mold surface, and this water droplet will drip and wet the lower mold surface, which not only impairs workability but also melted resin that becomes the base material. The temperature was lowered, the fluidity of the molten resin was deteriorated, and the moldability was also adversely affected.

On the other hand, if the mold temperature is too high, the cross-sectional structure of the fabric layer of the sheet-shaped multilayer material is necessarily formed with a gap structure having air permeability, so that there is no barrier effect and the sheet during mold clamping is not formed. The air in the foam layer bubbles of the multi-layered material is not sealed here but leaks to the fabric layer side. As a result, the air pressure in the bubbles is reduced, and the heat and the pressing force of the molten resin are applied in the initial stage of mold clamping, and the bubbles in the foam layer are crushed. By the collapse of the air bubbles, the thickness of the foam layer is not restored even after the mold is opened, and the product has a reduced cushioning property.

Further, since air leaks to the fabric layer side, heat of the molten resin is transferred to the compressed fabric layer, which adversely affects the fabric layer. That is, the effect of the heat and the mold clamping pressure causes a so-called ironing effect, which causes the fabric to collapse and the pile shrinks, the thickness of the fabric is not restored even after the mold is opened, and the texture of the fabric layer deteriorates. It is easy to become a product.

In this way, during molding, due to the influence of the high melting resin temperature, the foam layer is destroyed, the texture is deteriorated due to the collapse of the fabric layer and the shrinkage of the pile, and the appearance quality is impaired and the product yield is reduced. It had many problems such as getting low. On the other hand, a molding method in which the mold temperature is too low can reduce the fluidity of the molten resin and can be applied to the molding of small parts such as pillars, but it is difficult to mold large parts such as door trims. There was a flaw in terms of aspect.

The present invention has been made in view of the above circumstances, and an object thereof is to integrally form a sheet-like multilayer material having a foam layer and a fabric layer by a compression molding method and a substrate. It is an object of the present invention to provide integrated molding of a decorative molded product which is excellent in appearance, quality and productivity.

[Means for solving problems]

The present invention is to fix a sheet-shaped multilayer material composed of a fabric layer for foaming and a foam layer on an open molding surface, place a required amount of molten resin as a base material on the opposite molding surface, and then clamp the mold. The method of integrally molding by means of
A method for integrally molding a decorative molded article, which comprises using a sheet-shaped multi-layer material having a 200 μm thermoplastic film.

Hereinafter, a detailed description will be given with reference to an example of the drawings. First
FIG. 1 is a sectional view showing an example of a decorative molded product according to the present invention. As shown in the figure, a decorative molded article 1 is composed of a base material 2 and a sheet-shaped multilayer material 3, and the sheet-shaped multilayer material 3 includes a cloth layer 4 for decoration, a film 5 and a foam layer 6. The fabric layer 4 is always integrally formed on the outside.

The base material 2 used here is made of a thermoplastic resin, and includes crystalline polypropylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, and propylene component 7.
A crystalline polyolefin resin such as a crystalline propylene-ethylene copolymer containing 0% by weight or more, or an acrylonitrile-butadiene-styrene copolymer, a polyamide resin or a polystyrene resin can be exemplified, but particularly low specific gravity is possible. From the viewpoint of the balance of physical properties and moldability, it is effective to use crystalline polypropylene or crystalline propylene-ethylene copolymer polypropylene containing 70% by weight or more of a propylene component. Further, the above resin, talc, mica, glass fiber, if necessary,
Fillers such as synthetic fibers, carbon fibers, metal fibers, cellulosic fibers, wood flour and the like can be added if necessary. The thickness of the substrate 2 is in the range of 1 to 4 mm, preferably 2 to
It is 3 mm. If the thickness is less than 1 mm, the fluidity at the time of compression molding is poor, the shape cannot be obtained, the rigidity of the decorative molded product is insufficient, and it is easily deformed. If the thickness exceeds 4 mm, the weight of the decorative molded product is reduced. It also increases the cost.

The sheet-shaped multi-layer material 3 is composed of a three-layer laminated body in which a fabric layer 4, a film 5 and a foam layer 6 are attached to each other. When applying the sheet-shaped multi-layer material, use one that has already been integrated by laminating.

It is a feature of the present invention that a film 5 is provided between the fabric layer 4 and the foam layer 6, and the film 5 is made of a thermoplastic resin having flexibility and good elongation and having a thickness of 30 to 200 μ or It is a sheet. As a desirable material,
Polypropylene, polyethylene such as low-density polyethylene, polyolefin-based thermoplastic elastomer, ethylene-vinyl acetate copolymer, or soft polyvinyl chloride is preferably used. As the film 5, a film of 50 to 150 μm made of random block copolymer polypropylene or soft polyvinyl chloride is particularly preferable. When the thickness is less than 30 μm, the film is broken by the bubble pressure during compression molding, and the foam layer 6 and the fabric layer 4 are adversely affected. On the other hand, when the thickness exceeds 200 μ, the soft feeling of the decorative molded article 1 is reduced and the cost is increased.

The fabric layer 4 used in the present invention is a decorative layer that determines a high-grade appearance, texture and feel, and is a woven fabric, a non-woven fabric or a knitted fabric, and a fabric having a brushed surface is particularly preferable. Specifically, woven or knitted fabrics such as tricot, moquette, jersey, plain weave made of synthetic fibers such as polyester fiber, polyamide, polyacrylonitrile, vinylon, etc., and fabrics having raised or piled surfaces are preferable. Further, it may be a cloth made of wool, cotton, rayon, a cloth woven with a mixed yarn of these and synthetic fibers, or a non-woven fabric made of polypropylene or polyester fibers.

The foam layer 6 of the present invention is a foam layer made of a thermoplastic resin and constitutes the back surface of the sheet-shaped multilayer material 3. Examples of the material for the foam layer include soft foam sheets such as foam polypropylene, foam polyurethane, foam polyethylene, and foam polyvinyl chloride. From the viewpoint of cushioning property, a foam layer 6 having a foaming ratio of 10 to 40 times and a thickness of 2 to 5 mm is preferable. Particularly, from the viewpoint of the adhesiveness between the base material layer 2 and the foam layer 6, when the base material layer 2 is polypropylene, it is preferable to use the same material such as using foamed polypropylene.

According to the integral molding method of the present invention, the mold, which is attached to the compression molding machine and has a predetermined constant temperature, is opened and stands by.
The sheet-shaped multilayer material 3 previously cut is fixed to the opened molding surface. (FIG. 2) A required amount of the molten resin 10 is placed between the opened molds. The mold is compressed at a predetermined pressure for a predetermined time and clamped. (Fig. 3) After that, release the mold,
The obtained molded product is taken out. An example of an integral molding method for obtaining the decorative molded article 1 is by cutting the peripheral unnecessary portion of the sheet-shaped multilayer material 3.

The compression molding machine used in the present invention is one that can control the mold clamping speed, the mold clamping pressure, and the mold temperature. Can rapidly clamping, pressure retention ^{50~100kg / cm 2, 5~30kg / cm} 2
It is preferable that the low pressure holding can be automatically set. The mold opening may be a vertical opening because of the relationship in which the molten resin 10 is placed, but may be a horizontal opening.

The molds 7 and 8 are preferably those whose temperature can be arbitrarily set,
Water that can pass cooling water or constant temperature water is preferable. Forming area of the mold may be a pillar 200 cm ² about small parts, may be a door trim 6000 cm ² of large parts. Mold temperature is
When the temperature is low, the cooling efficiency of the molten resin 10 is good, but when the temperature is too low, the molten resin 10 contacting the surface of the mold 8 at the time of mold clamping is excessively cooled and the fluidity is lost and the moldability is hindered. On the other hand, if the temperature is too high, the fabric layer 4 may fall over or the fabric may become coarse (the fabric may open and become crater-like), and the elasticity of the foam layer 6 may be significantly reduced, and the fabric appearance, texture, and elasticity may be reduced. Be damaged. This appropriate temperature range is 20-60 ° C
Is desirable. The mold temperature may be the same for the sheet-shaped multilayer material side mold 7 and the molten resin side mold 8, but in order to strongly cool the sheet-shaped multilayer material 3 which is difficult to cool, the mold for the sheet-shaped multilayer material side is strong. It is preferable to set the mold 7 at a temperature lower than the mold 8 on the molten resin side by 20 ° C. or more. In order to improve the fluidity of the molten resin 10, it is preferable to set the temperature of the die 8 on the molten resin side to a temperature higher than that of the die 7 on the sheet-shaped multilayer material side, because the moldability is good. By setting the die on the sheet-shaped multilayer material side 7 at a low temperature, a further effect can be expected in maintaining the appearance quality of the fabric layer.

As shown in FIG. 2 as an example, the fixing of the sheet-shaped cover material 3 is performed by contacting the molding surface of the upper mold 7 with the fabric layer 4 side facing outward. The fixing method may be vacuum suction at the peripheral portion of the upper mold 7, or a suitable method such as a clip or pinning may be used.

The required amount of molten resin 10 is placed between the opened molds. The method of placing between the dies includes sheet-like surface placement, line placement, and point placement, and a predetermined amount may be placed at a predetermined position controlled by a microcomputer or the like. The amount of the molten resin 10 is determined by the size of the molded product and its thickness.

Next, the mold is clamped. (Fig. 3) For mold clamping,
Pressure increase, pressure retention, pressure reduction, and combinations thereof are performed. At the start of mold clamping, the mold clamping pressure is set to 50 to 100 kg / cm ² , hold for 5 to 20 seconds after reaching the set pressure, and then set the mold clamping pressure to 5 to 5.
An example is a method of reducing the pressure to 30 kg / cm ² and holding it for 10 to 60 seconds.

After integrally molding under the above conditions, the mold is opened and a molded product having a predetermined shape is taken out.

An example of an integral molding method in which a decorative molded product 1 is obtained by removing unnecessary peripheral portions of a molded product having a predetermined shape.

[Action]

In the integral molding of the present invention, the sheet-shaped multilayer material 3 and the molten resin 10 are fused and integrated by mold clamping. At the time of mold clamping, the sheet-shaped multilayer material 3 and the molten resin 10 are pushed into the mold gap. By clamping the mold, the molten resin spreads to form a molded product having a predetermined shape and thickness. For example, in the mold gap 3.2mm,
Sheet-shaped multi-layer material About 5 mm thick (2 mm fabric layer, 80 μ film and 3 mm foam layer) and set thickness 2.5 mm of molten resin 10 are clamped. 0.5mm will be pushed into the mold gap 3.2mm.

The thickness of the 2.5 mm molten resin 10 does not change even when compressed, so the difference between the die gap 3.2 mm and the molten resin 2.5 mm is 0.
The sheet-shaped multilayer material 3 of about 5 mm is compressed within 7 mm, and the bubbles of the foam layer 6 and the fabric layer 4 of the sheet-shaped multilayer material are compressed.
The compressive force of the fibers presses the sheet-shaped multilayer material 3 and the molten resin 10.

If there is no film between the foam layer and the fabric layer, there is nothing to seal and air bubbles in the foam layer will escape from the fabric layer. For this reason, the foam layer becomes thin, has no cushioning properties, and becomes a decorative molded article of a fabric layer having a bad appearance with hair collapse and pile shrinkage.

On the other hand, when the sheet-shaped multilayer material 3 having the film 5 between the fabric layer 4 and the foam layer 6 is integrally molded, the bubbles of the foam layer 6 do not escape from the fabric layer 4. As the compressed air bubbles are released as the mold is opened, the size of the original air bubbles is restored. Bubbles in the foam layer 6
Since it does not come off, the heat of fusion of the molten resin 10 is insulated and the thickness of the fabric layer 4 is restored. Cushioning is maintained with a good-textured fabric that does not have hair collapse or shrinkage of the pile. The molten resin 10 that has spread out is cooled and becomes the base material 2.

〔Example〕

Next, an example of the method for producing the decorative molded product 1 will be described with reference to FIGS. 2 and 3 showing the manufacturing process of the decorative molded product of the present invention.

In this embodiment, the sheet-shaped multi-layered material 3 is made of a polyester fiber and has a tricot weave cloth layer 4 (thickness: about 2 mm) 4 having a raised surface, and a back surface made of a soft polyvinyl chloride barrier having a thickness of 80 μm. A three-layer laminate (total thickness is about 5 mm) is formed by adhering the film 5 and further adhering a cross-linked polypropylene foam layer 6 having a foaming ratio of 20 times and a thickness of 3 mm on the back surface of the barrier film 5. The molten resin 10 forming the base material 2 has excellent mechanical properties such as rigidity and impact resistance, and is suitable for compression moldability, and is made of Chisso filler composite polypropylene (density 1.05 g / cm ³ , melt florate 38 g). The charge amount of the molten resin 10 was set in advance so that the thickness of the substrate 2 was 2.5 mm.

First, after cutting the above-mentioned sheet-shaped multilayer material 3 into a desired shape, as shown in FIG. 2, the sheet-shaped multilayer material 3 is attached to a predetermined position of the upper die 7 of the molding machine which is open vertically and stands by. At this time, the sheet-shaped multilayer material 3 is placed on the upper mold 7 with the fabric layer 4 side facing upward.
Place it in contact with the molding surface of.

Next, a resin pouring nozzle 9 mounted on the tip of an extruder (not shown) enters between the upper die 7 and the lower die 8 and relatively moves in accordance with the shape of the molded product, and the pouring nozzle 9 Further, the molten resin 10 of polypropylene is charged in a required amount and placed in the molding surface area of the lower mold 8.

After that, the resin pouring nozzle 9 is withdrawn from the mold, and the upper mold 7 and the lower mold 8 are immediately engaged to perform mold clamping. By this mold clamping, as shown in FIG. 3, the molten resin 10 is pressure-molded into a shape along the cavity formed between the upper mold 7 and the lower mold 8, and at the same time, The mold 7 and the lower mold 8 cool and solidify to form the base material 2 having a predetermined shape. At the same time, the sheet-shaped multilayer material 3 is integrally molded with the base material 2.

Here, in this embodiment, the mold gap of the cavity is set to 3.2 m.
Since it was set to be m, the thickness of the base material 2 will be 2.5
When mm is subtracted, the sheet-shaped multilayer material 3 is clamped and held in a state of being compressed to 0.7 mm. This corresponds to about 14% of the original thickness of the sheet-shaped multilayer material 3 of 5 mm.

Next, after opening the upper mold 7 from the lower mold 8, the molded product in which the base material 2 and the sheet-like multilayer material 3 are integrated is taken out from the mold, and the peripheral unnecessary portion of the sheet-like multilayer material 3 is removed. Cut it off
A decorative molded article 1 having a cross-sectional shape as shown in FIG. 1 is obtained.

When the appearance of the decorative molded article 1 was observed, a product having good appearance quality with less hair collapse of the fabric layer 4 and shrinkage of the pile and a soft feeling and not impairing the texture of the tricot was obtained. Next, when observing the cross section of the decorative molded article 1, the measurement result of the thickness distribution of the polypropylene base material 2 is 2.5 ± 0.
It is molded to a uniform thickness of 1 mm. The polypropylene foam layer 6 was found to have almost the original shape with less crushing of bubbles except for the interface layer that was heat-sealed with the molten resin 10, and the average thickness of the foam layer 6 was about 2.4 mm. Has become
The thickness recovery rate is about 80% with respect to the original thickness of 3 mm. Further, the fabric layer 4 has a thickness of about 1.8 mm including the raised portion, and shows a thickness restoration rate of 90% or more.

As described above, the film 5 does not tear as a whole and plays a role of protecting the foam layer 6 and the fabric layer 4. The molding conditions in this example were set as follows.

○ Charge temperature of molten resin 10: 200-205 ℃ ○ Temperature of upper mold 7: 25 ℃ ○ Temperature of lower mold 8: 60 ℃ ○ Initial mold clamping pressure: 75kg / cm ² ○ Holding pressure: 15kg / cm ² ○ Clamping retention time: 35 sec [Comparative Example] Except that a sheet-like multilayer material composed of a two-layer laminate in which a fabric layer and a foam layer were directly adhered was used without using a film.
Molding was carried out under the same conditions as in the above example. When observing the finished decorative molded product, the foam layer is considerably crushed, and its thickness is crushed to about 1 mm or less to about 0.8 mm (thickness restoration rate is about 30%), and the cuttability is remarkably impaired. Not only that, but a small dent appears on the entire surface of the fabric,
In addition, hair collapse and pile shrinkage have occurred, and the thickness of the fabric layer has decreased to an average of about 1 mm (thickness restoration rate of about 50%).
It was a product with poor appearance quality.

〔The invention's effect〕

In the integral molding method of the present invention, since the film is interposed between the fabric layer and the foam layer, the bubbles of the foam layer cannot be removed from the fabric layer even when integrally molded by the mold clamping force. Therefore, the thickness of the foam layer of the sheet-shaped multi-layer material before molding was 3 mm.
The foam layer thickness of the decorative molded article of the conventional molding method was 0.8 mm, whereas the foam layer thickness of the present invention was 2.4 mm, and the cushioning property was good.

In the integral molding method of the present invention, since the film is interposed between the fabric layer and the foam layer, the foam layer remains and the heat of fusion of the substrate is not transmitted to the fabric layer. Therefore, while the sheet-shaped multilayer material before molding had a fabric layer thickness of 2 mm, the decorative layer molded article of the conventional molding method had a fabric layer thickness of 1 mm, whereas the fabric layer thickness of the present invention was 2 mm. The size was 1.8 mm, and there was no hair collapse or shrinkage of the pipe, and a product with a good appearance was obtained.

In the integral molding method of the present invention, since the film is interposed between the fabric layer and the foam layer, air bubbles in the foam layer cannot escape from the fabric layer during molding. Therefore, in order to prevent bubbles in the foam layer from leaking from the fabric layer, it can be carried out with a room temperature mold as compared with conventional molding which is carried out with a low temperature mold of 10 ° C. or lower. Due to the fluidity of the molten resin, the integral molding method of the present invention can be applied to a molding area of a door trim, etc.
Large parts of about 00 cm ² can be produced efficiently and easily.

As described above, the integral molding using the sheet-shaped multi-layered material in which the film of the present invention is interposed does not crush the foam layer and the fabric layer and does not require a low temperature mold. Therefore, it is an integral molding method that can be suitably used as a decorative molded article for automobile interiors and the like, which has a good cushioning property, a feeling, and a soft touch feeling and has a high-class appearance.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a decorative molded product according to the present invention, and FIGS. 2 and 3 are drawings for explaining a manufacturing process of the decorative molded product of the present invention. FIG. 3 is an elevation view of a main part of the molding machine showing a state where the sheet-shaped multilayer material and the molten resin are placed on the mold before the mold is clamped, and FIG. 1 ... Decoration molded article, 2 ... Substrate, 3 ... Sheet-like multilayer material, 4 ... Cloth layer, 5 ... Film, 6 ... Foam layer, 7
…… Upper mold, 8 …… Lower mold, 9 …… Resin pouring nozzle, 1
0: Molten resin

Claims (1)

[Claims] 1. A sheet-shaped multi-layer material comprising a fabric layer for foaming and a foam layer is fixed to an open molding surface, and a required amount of molten resin serving as a base material is placed on the opposite molding surface, and then a mold is formed. It is a method of integrally molding by tightening, in which the space between the fabric layer and the foam layer is 30
A method for integrally molding a decorative molded article, which comprises using a sheet-shaped multi-layer material having a thermoplastic film having a thickness of ˜200 μm.