JP3119930B2 - Molding method for laminated molded products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber-reinforced thermoplastic resin core and a non-breathable decorative skin (hereinafter referred to as a non-breathable decorative skin), a breathable porous sheet (hereinafter referred to as a "breathable skin"). This air-permeable porous sheet is referred to as a porous sheet). The laminated molded article according to the present invention is widely used for interior parts of automobiles, housing parts such as home electric appliances, and industrial parts such as furniture.

[0002]

2. Description of the Related Art In recent years, there has been a tendency that industrial parts manufactured by press working of metal are replaced with press-formed products of fiber reinforced thermoplastic resin composed of relatively long reinforcing fibers and thermoplastic resin. is there. The feature of the fiber-reinforced thermoplastic resin is that the sheet-shaped molding material of the fiber-reinforced thermoplastic resin which is softened by heating (hereinafter, the molding material is referred to as a sheet-shaped molding material)
Can be manufactured at room temperature or in a heated mold and press-molded in a short time to produce a complex molded product, and the molded product has high strength and is lightweight.

[0003] The method of manufacturing a sheet-shaped molding material can be classified into the following two methods. Laminating method: Laminate a mat-like reinforcing fiber and thermoplastic resin that have been subjected to needling (a process of sticking needles into a plurality of reinforcing fiber bundles and entangled with each other), and continuously between steel belts of a double belt conveyor type continuous press. Insert, heat, pressurize,
A method of producing a sheet-shaped molding material by further cooling (JP-A-48-80172, JP-A-52-40558, and JP-A-55-77525); And the diameter is 3-30 μm φ,
A non-woven material is manufactured by uniformly dispersing a reinforcing fiber having a length of 3 to 50 mm and a thermoplastic resin powder. This non-woven material is used as an intermediate product, heated and pressed, and then cooled to manufacture a sheet-shaped molding material. (JP-B-52-12283, JP-B-55-9119).

[0004] Before molding, the sheet-like molding material is heated to a temperature higher than the softening point or melting point of the thermoplastic resin constituting the matrix. The sheet expands due to the springback that attempts to return to its original state, and the reinforcing fibers are more exposed on the sheet surface. Exposure of the reinforcing fibers on the sheet surface leads to exposure of the reinforcing fibers on the molded product surface,
Deterioration in appearance is a problem.

[0005] A method of obtaining a laminated molded article by superimposing a decorative skin on the surface of a heated sheet-shaped molding material and simultaneously pressing and molding the same to obtain a laminated molded article is very important in improving the appearance of the molded article. This is an effective means. For the purpose of improving the appearance of molded products using sheet-shaped molding materials,
Laminated molded articles and molding methods thereof have been proposed. In this method, when laminating the sheet-shaped molding material and the air-impermeable skin, air in the expanded sheet-shaped molding material remains between them, and good adhesion cannot be obtained, so that they are easily peeled off. The adhesion between the skin and the fiber reinforced thermoplastic resin layer is improved by interposing a porous sheet as a cushioning material and defoaming during lamination and integral molding (Japanese Patent Publication No. 61-59231).
No.). In this method, a porous sheet is stacked on the back surface of a non-breathable skin and laminated and integrated, and then laminated so that the heat-softened sheet-shaped molding material and the porous sheet are in contact with each other, and the room temperature or a heated mold. And press molded in a short time to obtain a laminated molded product. Usually, a plastic sheet or film is used as the non-breathable skin. As the porous sheet, a woven fabric, a knitted fabric, or a nonwoven fabric made of various fiber materials is used.

However, when a laminated molded article having a complicated shape is formed by this method, wrinkles are generated on the skin, and the appearance of the skin is reduced by whitening due to stretching of the skin.
This phenomenon occurs because the heat of the sheet-shaped molding material heated to the air-impermeable skin (plastic sheet) is not sufficiently transmitted due to the low thermal conductivity of the porous sheet, and the skin is rapidly formed in a solid phase state. Occur. By increasing the temperature of the mold, integral molding can be performed in a state where the skin is softened, but the cycle time of molding becomes longer, which is industrially disadvantageous.

[0007]

DISCLOSURE OF THE INVENTION The present invention relates to a laminated molded article formed of a non-breathable skin, a porous sheet, and a sheet-shaped molding material, and has a good adhesion between the skin and the fiber-reinforced thermoplastic resin layer. Another object of the present invention is to provide a molding method which develops properties and at the same time improves the appearance of the skin due to wrinkles and whitening.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a sheet-like sheet obtained by stacking a porous sheet on the back of a non-breathable skin formed into a predetermined shape, placing the sheet on a molding die, and further heating and softening the sheet. After overlapping the molding material so that it contacts the porous sheet,
This is a method for forming a laminated molded product, wherein the whole is laminated and integrated by pressure molding.

FIG. 1 shows an example of a method for forming a laminated molded product according to the present invention. Non-breathable skin 1 is placed in far infrared heating furnace 2
Heat above its softening point or melting point. Place the heated non-breathable skin in a mold 3 designed for vacuum forming,
Vacuum forming is performed along the shape of the forming die. On the other hand, the sheet-shaped molding material 4 is heated in a far-infrared heating furnace to a temperature higher than the softening point or melting point of the thermoplastic resin constituting the matrix.
The porous sheet 5 is superimposed on the non-breathable skin formed into a predetermined shape, and the heated sheet-like molding material is further laminated and integrally molded in a molding die to trim the peripheral portion of the product. Thereby, the appearance of the skin is improved, and the laminated molded product 6 having good adhesion between the skin and the fiber-reinforced thermoplastic resin layer can be obtained.

[0010] The non-breathable skin is heated to a softening point or a melting point or higher before lamination and integral molding, and is vacuum-molded in a softened state. Therefore, appearance problems such as wrinkling and whitening due to stretching are caused. Is resolved. In addition, since the porous sheet is present as a cushioning material between the skin and the heated sheet-shaped molding material, the defoaming at the time of laminating and integrally forming is excellent between the skin and the fiber-reinforced thermoplastic resin layer. High adhesion is obtained. In the defoaming process, as the lamination integral molding proceeds, the porous sheet becomes an air passage and is exhausted toward the periphery of the molded product, and finally passes through the shear edge of the molding die and out of the mold. Is discharged. The shear edge is a contact portion of the upper and lower molding dies for forming a peripheral portion of a molded product, and is provided with a minute clearance for discharging air but minimizing resin outflow.

A feature of the present invention is the use of a non-breathable skin shaped into a predetermined shape in the formation of a laminated molded product, and the wrinkles and whitening of the skin seen in a complex molded product by a conventional method. Is significantly reduced.

In the method of forming a laminated molded product shown in FIG.
Although a far-infrared heating furnace is used for heating the skin and the sheet-shaped molding material, other ventilation or radiation heating furnaces can also be used. Although the shaping of the skin was performed by vacuum forming, a similar shaped skin could be obtained by air pressure forming and press forming. Further, although the skin molding is performed in the integral molding die, the same effect can be obtained by a method in which the skin is shaped by another mold dedicated to the skin molding and then inserted into the integral molding die. Further, the porous sheet is superimposed thereon after the skin is formed, and the heated sheet-shaped molding material is further laminated and integrally formed. The porous sheet is previously heat-sealed or bonded to the back surface of the skin. In the case of using a material laminated by bonding through the intermediary, the superposition step can be omitted and the process is more efficient.

According to the present invention, the non-breathable skin is smooth,
Alternatively, a plastic sheet or film subjected to a graining process such as a cloth or a leather pattern, a metal sheet coated with a metal powder, or a metal-coated plastic sheet or film is used. As the porous sheet, a woven fabric, a knitted fabric, or a non-woven fabric made of various fiber materials such as organic fibers such as natural and chemical fibers, glass fibers, carbon fibers, and metal fibers are used.

The sheet-like molding material for forming the fiber-reinforced thermoplastic resin layer, which is the core of the laminated molded product, is a flat fiber composed of a reinforced fiber produced by a laminating method or a papermaking method and a thermoplastic resin. A reinforced thermoplastic resin sheet is used. Examples of the reinforcing fibers include glass fibers, carbon fibers, and metal fibers, as well as inorganic fibers and organic fibers. Examples of the thermoplastic resin include polyethylene, polypropylene, polystyrene, styrene-butadiene-acrylonitrile copolymer, and styrene-acrylonitrile copolymer. Polymers, polyamides, polycarbonates, polyacetals, polyethylene terephthalate, polybutylene terephthalate, polyphenylene oxide, polysulfone, resins such as polyphenylene sulfide, or a mixture of two or more of these, further, a plasticizer generally used for these, Heat stabilizers, light stabilizers, fillers, dyes and pigments, impact resistance,
Those to which an extender, a nucleating agent, a processing aid, and the like are added are exemplified.

[0015]

The present invention will be described in detail below with reference to examples. Example 1 A 3.7 mm-thick sheet-like molding material made of a papermaking method and made of 40% by weight of a glass fiber having a diameter of 10 μm and a length of 13 mm as a reinforcing fiber and 60% by weight of a polypropylene resin as a matrix resin was used. . A 0.5 mm thick polyvinyl chloride sheet was used as the non-permeable skin, and a cotton medical gauze cloth was used as the porous sheet. Using these sheet-shaped molding materials, air-impermeable skin, and porous sheet, the laminate molding method shown in FIG.
A 6 mm-thick laminated molded product was molded in a box shape of mm.

The polyvinyl chloride sheet used for the skin is 45
Cut to 0x450mm and soften sufficiently in a far infrared heating furnace 1
It was heated to 60 ° C., placed on a mold designed for vacuum forming, and the skin was formed by vacuum forming. Subsequently, a gauze cloth cut into 400 × 400 mm was overlaid on the molded skin. The sheet-shaped molding material is 270 x 270mm
Each of the three pieces was heated in a far-infrared heating furnace until the internal temperature reached 200 ° C. The heated sheet-shaped molding material expanded to about twice the original thickness, and air was present inside. Three of these heated sheet-like molding materials are superimposed, laminated on a gauze cloth in a molding die, the upper die is immediately lowered, and press molded at a molding pressure of 200 kgf / cm ² to form a laminated molded product. did.

The molded article was completely covered with the skin, had no wrinkles or whitening, and had a good appearance. In addition, no air pockets were observed between the skin and the fiber-reinforced thermoplastic resin layer, and the adhesion of the skin was measured by a 90-degree peel test. As a result, an adhesive strength of 0.5 kgf / cm was obtained. The epidermis had peeled off at the interface with the gauze. Observation of the peeled surface confirmed that the gauze cloth was sufficiently impregnated with the polypropylene resin from the sheet-shaped molding material at the time of molding.

Example 2 In the same manner as in Example 1 except that a sheet-shaped molding material obtained by the paper-making method of Example 1 and a polyvinyl chloride sheet were used, and a polyester fiber nonwoven fabric (weighing 80 g / m ² ) was used as a porous sheet. A laminated molded article was formed. Also in this molded product, a good appearance was obtained as in Example 1. No air pockets were observed between the skin and the fiber-reinforced thermoplastic resin layer, and the adhesive strength of the skin was 0.4 kgf / cm. The skin was peeled off at the interface with the polyester fiber nonwoven fabric. By observing the peeled surface,
It was confirmed that the polyester fiber nonwoven fabric was sufficiently impregnated with the polypropylene resin from the sheet-shaped molding material at the time of molding.

Example 3 A skin obtained by laminating a polyester fiber nonwoven fabric (weighing 80 g / m ² ) in advance on the polyvinyl chloride sheet of Example 1 by heat-sealing, and a sheet-shaped molding material by the papermaking method of Example 1 Was used to form a laminated molded product. The laminate skin was cut at 450 × 450 mm in the same manner as in Example 1 and heated in a far-infrared heating furnace to 160 ° C. where the polyvinyl chloride sheet was sufficiently softened, and the polyvinyl chloride sheet was placed on a mold designed for vacuum forming. It was placed so as to be on the side, and the skin was formed by vacuum forming. Furthermore, three sheet-like molding materials heated in a far-infrared heating furnace are superimposed on the molded laminate skin until the internal temperature reaches 200 ° C., and the upper mold is immediately lowered to press-mold at a molding pressure of 200 kgf / cm ^2. Thereby, a laminated molded product was molded.

In this molded product, a good appearance was obtained as in Example 1. No air pockets were observed between the skin and the fiber-reinforced thermoplastic resin layer, and the skin had an adhesive strength of 2.6 kg.
f / cm. Cohesive peeling, in which the skin peeled while damaging the polyester fiber nonwoven fabric, was observed. In this method, a polyester fiber non-woven fabric is firmly laminated on a polyvinyl chloride sheet by heat fusion in advance, and the polyester fiber non-woven fabric is sufficiently impregnated with a polypropylene resin from a sheet-shaped molding material at the time of molding. Strength was obtained. As the skin material, using a porous sheet laminated on a non-breathable skin by heat-sealing or bonding via an adhesive can improve the adhesive strength of the skin and at the time of forming the porous sheet in the forming step. Can be omitted, and there is a merit of shortening the process.

Example 4 A 3.7 mm-thick sheet-like molding material made of a laminating method, comprising a reinforcing fiber of 23 μm in diameter, 40% by weight of a mat-like glass fiber, and a matrix resin of 60% by weight of a polypropylene resin. A laminated molded product was formed in the same manner as in Example 3 using the skin obtained by laminating the polyester fiber nonwoven fabric on the polyvinyl chloride sheet of Example 3. When heated in a far-infrared heating furnace until the internal temperature of the sheet-shaped molding material by the laminating method reached 200 ° C., it expanded to about three times its original thickness.

In this molded product, a good appearance was obtained as in Example 1. No air pockets were observed between the skin and the fiber-reinforced thermoplastic resin layer, and the skin had an adhesive strength of 2.8 kg.
f / cm. As for the peeling of the skin, cohesive peeling was observed in which the polyester fiber non-woven fabric was peeled while being damaged in the same manner as in Example 3.

Comparative Example 1 Using a sheet-like molding material obtained by the papermaking method of Example 1 and a polyvinyl chloride sheet, a polyvinyl chloride sheet formed by laminating a molded article was cut at 450 × 450 mm and placed on a molding die.
The three sheet-shaped molding materials heated in the far-infrared heating furnace are directly stacked on the skin until the internal temperature reaches 200 ° C., the upper mold is immediately lowered, and press molding is performed at a molding pressure of 200 kgf / cm ^2. A molded article was molded. In this laminated molded product, wrinkles and whitening of the skin occurred at the corners of the molded product, and a large number of air pockets between the skin and the fiber-reinforced thermoplastic resin layer were observed throughout the molded product, and a reduction in appearance was observed. The epidermis was not adhered at all and the adhesive strength was 0 kgf / cm.

Comparative Example 2 A laminated molded article was molded in the same manner as in Comparative Example 1 using the sheet-like molding material obtained by the papermaking method of Example 1 and the skin obtained by laminating a polyester fiber nonwoven fabric on the polyvinyl chloride sheet of Example 3. did. The laminated skin is cut into 450 x 450 mm and placed on a mold so that the polyvinyl chloride sheet side is down, and three sheet-shaped molding materials heated in a far-infrared heating furnace until the internal temperature reaches 200 ° C are laminated. Lay it on the skin material, immediately lower the upper mold,
The laminate was molded by press molding at 0 kgf / cm ² .

In this laminated molded product, as in Comparative Example 1, wrinkles and whitening of the skin occurred at the corners of the molded product, and a reduction in appearance was observed. However, no air pockets were observed between the skin and the fiber-reinforced thermoplastic resin layer, and the adhesive strength of the skin was 2.3.
Kgf / cm. As for the peeling of the skin, cohesive peeling was observed in which the polyester fiber non-woven fabric was peeled while being damaged in the same manner as in Example 3.

[0026]

According to the present invention, a fiber-reinforced thermoplastic resin molded article, which has been conventionally regarded as a problem, is formed by laminating and forming a non-breathable skin, a porous sheet, and a fiber-reinforced thermoplastic resin sheet-shaped molding material. The appearance could be improved. The feature of the present invention is that the skin material is preformed into a predetermined shape prior to carrying out the lamination integral molding, and in a complicated laminated molded product, wrinkles of the skin, good whitening and the like do not occur. Get the look.

The laminated molded article of the present invention does not require secondary processing such as painting, which has been performed for the purpose of improving the appearance of a fiber-reinforced thermoplastic resin molded article, can achieve a reduction in product cost, and can be used as an interior material for automobiles. Or, it can be widely applied to housing parts such as home electric appliances and industrial parts such as furniture.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a method for forming a laminated molded product.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Non-breathable skin 2 Far-infrared heating furnace 3 Mold 4 Sheet-shaped molding material 5 Porous sheet 6 Laminated molding

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI // B29K 105: 06 B29L 9:00 (56) References JP-A-51-71375 (JP, A) JP-A-2-136221 (JP, A) JP-A-2-175232 (JP, A) JP-A-51-112889 (JP, A) JP-A-62-214938 (JP, A) JP-A-5-2944 (JP, U) ( 58) Field surveyed (Int.Cl. ⁷ , DB name) B29C 70/06 B29C 51/10 B29C 51/14 B29C 51/42 B32B 5/28 101

Claims (1)

(57) [Claims] 1. A fiber-reinforced thermoplastic resin sheet formed by superimposing a gas-permeable porous sheet on the back surface of a non-air-permeable decorative skin formed in a predetermined shape, placing the gas-permeable porous sheet in a mold, and heat-softening the sheet. A method for molding a laminated molded product, comprising laminating materials so as to be in contact with a gas-permeable porous sheet and then press-molding the whole to laminate and integrate the whole.