JPS6159231B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laminate molded product having a core made of a fiber-reinforced thermoplastic resin sheet and a method for molding the same.

The fiber-reinforced thermoplastic resin sheet referred to in the present invention is one in which the reinforcing material is glass fiber, etc., and the thermoplastic resin is in the matrix. In particular, the fiber-reinforced thermoplastic resin sheet is one in which a reinforcing material made of relatively long mat-like fibers is impregnated with a thermoplastic resin matrix. It is.

The sheet is trim-cut according to the size of the molded product to be obtained (the cut material before molding is hereinafter referred to as a blank), and then heated and softened in a heating furnace to a temperature higher than the softening temperature of the matrix resin (hereinafter referred to as a heated blank). ), the heated blank is then press-molded in a matted metal die kept at a temperature below the softening temperature of the matrix resin, and by solidifying it, it can be molded into a molded article with a desired curved surface shape. .

According to this method, large-scale press molding of thermoplastic resin containing relatively long fiber reinforcement is possible,
Another feature is that the time required for molding is short. Furthermore, the molded product thus obtained exhibits excellent physical properties due to the reinforcing effect of the long fiber reinforcement, and is attracting attention as a lightweight structural material that can replace steel.

However, a disadvantage of the seed molded product is that the reinforcing fibers protrude on the surface of the molded product, resulting in poor appearance.

Therefore, forming another decorative surface by laminating it on the surface of the molded product is extremely effective for the molded product made of the seed fiber-reinforced thermoplastic resin sheet.

To achieve this purpose, when a heated blank is placed on the die surface of a matted metal die during press forming, a sheet with a decorative surface is placed on top of it (hereinafter this sheet is referred to as an overlay sheet). If it is possible to attach a decorative surface to the surface of a molded product by shaping it by pressing and simultaneously bonding and integrating the two, it is an economically extremely advantageous method (hereinafter this molding method will be referred to as overlay molding). ).

However, when overlay molding was attempted using a non-air permeable, smooth-surfaced sheet as an overlay sheet with its smooth surface in contact with a heated blank, the overlay sheet and the molded object formed from the blank came into close contact. It was found that there were some parts that were not bonded, and even if there were parts that were in close contact, there was no bonding force and they were easily peeled off.

The reason for this is that the reinforcing fibers expand when the blank is heated and contain air inside, but if pressure is applied in this state, the air between the heated blank and the overlay sheet cannot be degassed sufficiently. ,
This is because it remains between the two. Regarding the bonding force between the two, the thermoplastic resin component in the heated blank flows through the press, is shaped, and solidifies when in contact with the smooth surface of the overlay sheet, so there is a special bond between the two. It cannot be expected to generate power.

The present invention was developed as a result of various studies on an overlay molding method that firmly connects and integrates the overlay sheet and the molded body without leaving any air bubbles between them. A breathable porous layer is laminated to the decorative skin, and the integrated sheet is overlaid so that the breathable porous layer is in contact with the surface of the heat-softened fiber-reinforced thermoplastic resin sheet. The inventors have discovered that the above objects can be achieved by press molding, and have thus completed the present invention.

Examples of reinforcing fibers in the reinforced thermoplastic resin sheet used in the present invention include glass fibers, carbon fibers, and amide fibers.

In addition, thermoplastic resins that are matrix resins include polyethylene, polypropylene, polyvinyl chloride, polymethyl methacrylate, ABS resin,
polyamide resin, polyethylene terephthalate,
Industrial materials include polybutylene terephthalate, polycarbonate, polyacetal, etc.
These thermoplastic resins are blended in appropriate proportions with the fiber-reinforced material formed in the form of mat, cloth, yarn, etc., and provided as an integrated flat fiber-reinforced thermoplastic resin sheet.

Next, the non-breathable decorative skin used in the present invention may be a plastic sheet (or film) or metal foil with a smooth surface, or with various textures such as cloth, leather pattern, or simulated leather. Examples include plastic sheets (or films) coated with metal vapor deposition.

Other examples include fibrous surfaces such as woven fabrics, knitted fabrics, non-woven fabrics, and flocked fabrics, which are breathable materials.
Examples include materials that have lost their breathability by backing up a film on the back side or by applying a coating treatment.

Examples of the porous layer used in the present invention include woven fabrics, knitted fabrics, non-woven fabrics, or glass fiber mats made of various fibrous materials, or breathable porous layers made of fibrous materials such as paper. ,
In order to laminate this onto the back side of the decorative skin, it can be bonded between the two using an adhesive, or if at least the back side of the decorative skin is made of thermoplastic, it can be bonded by heat fusion. be able to.

Next, a molding method using the blank fiber-reinforced thermoplastic resin and overlay sheet (breathable porous sheet) constructed as above will be described with reference to the drawings.

First, the blank 1 is trimmed to approximately the size of the desired molded product, and then, as shown in Fig. 1, it is placed in an infrared heating furnace 3, where it is heated from its upper and lower surfaces to a temperature higher than that at which the resin constituting the matrix melts. Heated blank 1' that has been heated and softened
becomes. As the matrix resin melts, the heating blank 1' becomes unable to suppress the repulsive force of the reinforcing fibers and expands in the thickness direction, resulting in it containing a large amount of air.

This heating blank 1' is placed on the mold surface 4a of the lower mold 4 of the mated metal die as shown in FIG.
Next, the overlay sheet 2 is laminated so that the decorative skin 2a is on the surface and the air permeable porous material 2b is in contact with the heating blank 1', and then the upper die 5 is immediately lowered to perform press molding.

The reinforcing fibers and molten resin that make up the softened heated blank flow through the cavity formed in the mold during press molding, when the upper mold 5 descends and the space between the two molds 4 and 5 is closed. However, on the side in contact with the overlay sheet 2, the press pressure is applied to the heated blank 1' through the overlay sheet 2, and flows along the air permeable porous surface of the overlay sheet 2. Then, the air in the heating blank 1' is absorbed by the mold surfaces 4a and 5a of both molds 4 and 5 as the upper mold 5 descends and press forming progresses.
Exhaust air is directed towards the peripheral part of the air.

Figure 3 shows the same mold in a closed state, and the space between the upper and lower molds 4 and 5 at the periphery forms a shear edge, and air is exhausted, but a minute clearance d is created to prevent the resin from flowing out as much as possible. In addition, the air permeable porous layer 2b has a function as a passage for dispersing and passing the air bubbles in the above-mentioned defoaming process, and therefore the air-permeable porous layer 2b has the function of dispersing and passing the air bubbles through the porous layer 2b. The air is discharged outside the mold through the clearance d.

In addition, in the case of an overlay sheet without the porous layer 2b, it is difficult for all the air contained in the heating blank to be degassed from the above-mentioned clearance, and there is a local gap between the overlay sheet and the heating blank. As a result, unevenness occurs, which significantly impairs the appearance of the product.

Another function of the porous layer 2b is to strongly bond the overlay sheet 2 to the surface of the molded product. In other words, through the press forming process described above, the cavity inside the mated metal die is completely filled with the heated blank and overlay sheet and closed leaving a shear edge clearance d, and a pressure of 100 to 150 kg/ ^cm2 is created inside the mold. is added.
As a result, defoaming is almost completed, and the molten resin permeates into the fiber structure inside the air permeable porous layer of the overlay sheet. And molds 4 and 5
Since the matrix resin is kept at a lower temperature than the softening temperature of the matrix resin, the matrix resin is cooled and solidified inside the mold, but the resin that has penetrated into the porous layer solidifies in this state, resulting in the porous layer and reinforcement. A strong bond can be formed between the thermoplastic resin layer and the thermoplastic resin layer.

Moreover, this bonding can be considered to be a physical anchoring effect that acts on the large contact surface area created by the fibers constituting the porous layer being embedded in the matrix resin.

On the other hand, in the case of an overlay sheet that does not have a porous layer, even if the overlay sheet is in close contact with the surface of the molded product, there is a flat surface between them, so no such bonding force occurs. ,
As a result, it becomes easy to peel off.

Therefore, the overlay molded product obtained by the present invention has a smooth surface without any air bubbles remaining on the surface as described above, has a strong bonding force with the blank, and has a large bonding strength with the blank. Since the intervening breathable porous layer also has a cushioning effect, this product can be used as a structural material for parts that require strength and appearance, such as exterior and interior materials for automobiles, casing parts for home appliances, etc.
It has a wide range of applications in furniture, furnishings, and industrial parts that require a metal layer on the surface.

Next, specific examples of the present invention will be described.
However, the present invention is not limited to the following examples.

Example 1 A reinforced thermoplastic resin sheet (trade name: Azdel, PPG
160mm with a thickness of 3.7mm and a unit weight of 4.3Kg/ ^m2
Two blanks cut to a size of 300 mm were used. A heated blank was obtained by heating the blank until the internal resin temperature reached 200°C. The blank contained air as the polypropylene matrix melted due to heating and expanded to about three times its original thickness due to the repulsive force of the reinforcing glass fiber mat. The press molding was carried out using a mated metal die as shown in FIG. 2 to obtain a box-shaped product. Approximate dimensions of the box are 190L x 390W x
40H, thickness 4t, corner outer surface R7, inner surface R3, draft angle 1° on the outer surface, 5° on the inner surface. Figure 3 shows the state when the mold is closed, and the peripheral part is marked d.
As shown in , there is a sear edge, and the sear edge clearance between the lower mated metal and the upper die is 0.5mm.

An overlay sheet was prepared in which 0.2 mm thick kraft paper was adhered in advance to the back side of a 0.3 mm thick hard vinyl chloride sheet using synthetic rubber latex as an adhesive.

As shown in Fig. 2, two heated blanks 2 were stacked on top of the lower mated metal 4 of a press molding die, and an overlay sheet was placed over the top of the heated blank so that the surface covered with kraft paper was in contact with the heated blank.

Preheat the overlay sheet in a hot air oven for 120 minutes.
It was heated at ℃ for about 30 seconds to soften it. The upper die was immediately lowered. The softened overlay sheet was squeezed as the upper die descended and was formed to cover the outer surface of the box. During the process of pressing, the air contained in the heated blank is exhausted from the peripheral edge clearance, but at this time, the paper layer stretched on the back of the overlay sheet disperses the air and allows it to pass through the edge clearance. It served the purpose of escaping. As shown in Figure 3, a pressure of 100 tons was applied and held for 20 seconds with the mold closed leaving a small seam edge clearance at the periphery. The mold temperature was kept at 50℃. In this state, degassing through the shear edge clearance was completed, the heated blank and the overlay sheet were brought into close contact, and the molten polypropylene was solidified while penetrating into the tissue space of the paper layer on the back side of the overlay sheet. An overlay molded article was thus obtained, and the peel strength between the overlay layer and the base layer was measured to be 0.5 kg/cm. This strength corresponds to the force with which the cellulose fibers embedded in the base layer are torn apart.

Comparative Example 1 Overlay molding was performed in the same manner as in Example 1, using a hard vinyl chloride sheet with a thickness of 0.3 mm as the overlay sheet. The overlay sheet is molded and covers the surface of the molded product, but on the top surface of the molded box, air remains over a wide area between the overlay sheet and the base of the molded product, and this area are not in close contact. Also, the peel strength between the overlay layer and the base layer was 0 for the portions of the sides of the box that were apparently in close contact with each other.

Example 2 The overlay sheet in Example 1 was replaced with the following one. A polyethylene terephthalate fiber nonwoven fabric (trade name: Spunlace Sontara #8000, manufactured by Toyo Products, unit weight: 40 g/m ² ) was adhered to the back side of a 0.25 mm thick aluminum foil using an epoxy adhesive. This sheet was drawn in advance using a press so that it conformed to the outer surface of a box, which was a molded product. At this time, the surface to which the nonwoven fabric was attached was made to be the inner surface.

When overlay molding is performed in the same manner using the same mold as in Example 1, two heated blanks are stacked on top of the lower mold, while the previously prepared laminated sheet of aluminum foil and nonwoven fabric is drawn as an overlay sheet. With the molded product inserted into the upper mold die, the upper mold was lowered to perform pressing. The adhesive bond between the aluminum layer and the base layer was good, and no air bubbles remained. Measuring the peel strength between the two
The strength is 2.4Kg/cm, which is equivalent to the strength that can tear the polyethylene terephthalate fibers that make up the nonwoven fabric.

Example 3 The overlay sheet in Example 1 was replaced with the following one. Polypropylene fiber needle punch carpet (manufactured by Dainik, unit weight 420g/m ² )
Synthetic rubber latex was applied to the back side of the sheet to form a non-porous sheet, and before drying the latex, a stockinette fabric (unit weight 80 g/m ² ) was pasted on and dried. In this way, an overlay sheet was obtained which had an air-permeable decorative surface layer and an air-permeable porous layer on the back side.

When performing overlay molding using the same mold as in Example 1 and using the same method, first cover the overlay sheet along the lower mold so that the surface of the needle punch carpet is in contact with the matted metal of the lower mold, and then cover the overlay sheet along the outer surface of the lower mold. The folded portions at the four corners of the overlay sheet were cut out in advance so that the overlay sheet could be molded. The overlay sheet was placed over the lower mold with the knitted fabric surface facing up, and two heating blanks were placed on top of this, and the upper mold was immediately lowered to perform press molding. A molded product was obtained in which the needle punch carpet was firmly attached to the inner surface of the box. Peel strength is 2Kg/cm
It was hot.

[Brief explanation of the drawing]

Figures 1 to 3 are for explaining the process of this invention, Figure 1 is an explanatory diagram showing the blank heating process, and Figure 2 is a diagram showing the blank and overlay sheet set on the press molding die. FIG. 3 is a sectional view showing the engaged state of the press molding die. DESCRIPTION OF SYMBOLS 1...Blank (fiber-reinforced thermoplastic resin sheet), 1'...Heating blank, 2...Overlay sheet, 2a...Non-breathable decorative skin, 2b...Breathable porous layer, 3...Infrared heating Furnace, 4...lower mold, 4a...mold surface, 5...upper mold, 5a...mold surface.

Claims (1)

[Scope of Claims] 1. A core made of a fiber-reinforced thermoplastic resin sheet molded into a desired molded product shape, and the thermoplastic resin of this core penetrates into the fibrous structure in a softened state and solidifies. A laminate molded article comprising a breathable fibrous porous sheet anchored to a core, and a non-breathable decorative skin adhered to one side of the porous sheet. 2. A breathable fibrous porous sheet is laminated on the back side of a decorative skin having a non-breathable decorative surface, and the breathable fibrous porous sheet is integrated with the decorative skin. , the fiber-reinforced thermoplastic resin sheet is heated and softened and placed on one mold surface, and the sheet is placed in contact with the surface of the mold surface, and then the other mold is heated and softened, and the fiber-reinforced thermoplastic resin sheet is placed on the mold surface. A method for forming a laminated molded product, which comprises engaging and pressurizing a breathable fibrous porous sheet so as to penetrate into the fiber structure thereof, thereby solidifying the sheet.