JP3033189B2 - Manufacturing method of painting molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a method for producing a painted product, and more particularly to a method suitable for painting a fiber reinforced plastic (FRP) product.

[Prior art]

FRP molded articles are used in a wide range of fields such as helmets, chairs, septic tanks and tanks, bathtubs and other housing-related equipment, and automobile parts because of their light weight and high strength. FRP molded products have poor surface smoothness, and sometimes reinforcing fibers may be exposed on the surface. Therefore, when forming a surface material or housing, it must be painted. However, in painting by painting, the type of paint that can be used is limited due to poor adhesion of the paint, and a desired pattern cannot be efficiently given to a molded product. There are also work environment issues. As a method of painting a molded article, a decorative sheet is also laminated, but this method is limited in the material of the decorative sheet that can be used, and the desired surface physical properties are not always obtained, and the shape of the decorative sheet is not necessarily obtained. Not applicable to complex molded products. Also, when trying to laminate a decorative sheet on a large one, wrinkles and blisters are likely to occur and it is not practical,
Large equipment is used for heating. As a method of manufacturing a so-called painting molded article, a technique of arranging a decorative sheet for painting in an injection molding die and painting at the same time as plastic injection molding is performed. Obtaining a large molded product by injection molding requires large equipment and expensive dies, which is economically disadvantageous. In addition, there is a limit to the length and the amount of fibers of the fiber reinforcement added to improve the strength. The applicant has already proposed, as a method of manufacturing a painted molded article which has solved such a problem, a method of performing painting simultaneously with compression molding of a plasticized plastic (Japanese Patent Application No. 2-130476). As a typical technology for manufacturing FRP molded products, SMC (Shee
t Molding Compound) method, cold press method, preform-matched die method and the like are known, but a method suitable for painting a product by these molding techniques has not been developed yet.

[Problems to be solved by the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method useful for producing a painted FRP molded article by a compression molding method, which has not been conventionally provided with an efficient method.

[Means for Solving the Problems]

The method for manufacturing a painted molded product of the present invention will be described with reference to the drawings. Basically, as shown in FIG. 1 or FIG. 2, an upper mold (1A) and a lower mold (1B) are used. A painting sheet (3) provided with a pattern printing layer or a metal deposition layer on a plastic substrate sheet is placed in a heated state on the upper and / or lower mold surfaces of the compression mold. 2, vacuum and / or pressure forming (vacuum forming in the illustrated example) is performed to pre-form the painting sheet, and then the fiber is placed on the lower mold as shown in FIG. A reinforcing material and a prepolymer of a curable resin are placed, and the upper mold is lowered or the lower mold is raised, and the mold is tightened as shown in FIG. 4 to perform compression molding, and as shown in FIG. It consists of obtaining a FRP molded product in which the painting sheet is integrated. The means for heating the sheet for painting is not particularly limited,
A hot plate in which a far-infrared heater or an electric heater is embedded is preferred. The preforming of the painting sheet is performed by using a compression mold (1A) as shown in FIG. This method is convenient because the preform can be directly moved to the next step without moving. For the preforming, a vacuum forming method, a compression forming method or a vacuum pressure forming method is preferable. In this case, the compression forming dies (1A, 1B) may be provided with a vacuum hole (11) or an air vent hole. In each case, it is advantageous to use a female mold for this preforming. However, depending on the surface you are painting, you may have to use a male type. In this case, it is preferable to provide a levee having a height equal to or higher than the highest surface of the mold around the portion to be the cavity. A positioning mark is provided on the painting sheet, the mark is detected by a sensor provided in the compression molding machine, and the painting sheet is placed at a predetermined position on the mold. It is preferable because synchronization with the shape can be surely achieved. As described above, one of the typical FRP compression molding methods is the SMC method, in which a prepolymer is impregnated from both sides into an aggregate of fiber reinforcement chops as shown in FIG. SMC (4) is the lower mold for compression molding (1B)
, And press and heat and press to obtain an FRP molded product as shown in FIG. Another typical example is a preform molded into a predetermined shape with a fiber reinforcing material and a binder, and a prepolymer placed on a lower mold, and the mold is tightened and heated and pressed to obtain a FRP molded product. Is the law. Another example is a cold press method in which a fiber reinforced material made into a preform or continuous strand mat using a binder and a prepolymer are supplied to a mold, and the mold is tightened and pressed to obtain an FRP molded product. can give. The thermosetting resin used as the molding material may be appropriately selected according to the molding method, and examples include a phenol resin, an epoxy resin, a diallyl phthalate resin,
Unsaturated polyester resin, polyimide resin and melamine resin. These prepolymers contain thickeners, fillers,
The optional additive such as a catalyst may be used.
Needless to say. Commonly used fiber reinforcing materials include glass fiber, carbon fiber, and metal fiber. Depending on the material, natural fibers or synthetic fibers can also be used. Type, content, length and form of fiber reinforcement (for example, as fiber or cloth)
May be determined according to the molding method and the use of the molded article. There are two types of painting sheets: a decorative sheet type that is integrated with the molded plastic and forms the surface of the molded product as it is, and a transfer sheet type that finally peels off the surface and exposes the layer underneath. Either one may be used in the present invention. As the decorative sheet and the transfer sheet, those using any materials can be used as long as they can be easily deformed according to the mold. As an example of a decorative sheet, a decorative layer and a surface protective layer are provided on a plastic base sheet by printing a picture or depositing a metal. The material of the decorative sheet, especially the base sheet, is selected in consideration of the shape of the molded article and the type of plastic to be integrated. For example, it may be selected from among vinyl resin, styrene resin, ABS resin, acrylic resin, polyolefin, cellulose derivative, polyamide and the like. The thickness depends on the use and shape of the molded product, but is usually about 20 to 1000 μm. For the protective layer, an acrylic resin or a fluororesin having excellent weather resistance and other surface properties, a mixture thereof, and a laminate are preferable. As a fluororesin, a co-extruded laminate sheet of polyvinylidene fluoride and poly (methyl methacrylate) or polyvinyl chloride, which has excellent adhesion to other resins, is placed on the surface where the polyvinylidene fluoride side contacts the mold. It is preferred to use. If you want the molded product to have abrasion resistance and abrasion resistance, use a semi-cured or touch-dried uncured ionizing radiation-curable resin layer with a protective layer as a protective layer and integrate it with the molded product. Thereafter, a method of irradiating ionizing radiation to cure the resin layer may be adopted. In addition, a decorative sheet whose surface is embossed or a protective layer is added with a bead pigment to make it matt, or a decorative sheet provided with a decorative layer on a part of a base sheet may be used. If necessary, apply an adhesive to the back of the decorative sheet. When a transfer sheet is used, any material having good moldability may be used as in the case of the decorative sheet. The material of the transfer board is preferably polyethylene terephthalate / isophthalate copolymer, polybutylene terephthalate, nylon / polyvinyl chloride laminate, or the like, particularly from the viewpoint of moldability into a three-dimensional shape. Usually, about 6 to 100 μm is appropriate. The transfer sheet generally has a decorative layer and an adhesive layer provided on a transfer sheet, and preferably has a release layer between the transfer sheet and the decorative layer, which becomes a protective layer after transfer.

[Operation]

According to the production method of the present invention, painting can be performed simultaneously with molding by disposing a painting sheet in a compression mold and performing compression molding of plastic. Thereby, a painted molded product of FRP having desired appearance and surface properties is realized.

Example 1 A colored polyvinyl chloride (PVC) sheet “R type” (manufactured by Riken Vinyl) having a thickness of 0.2 mm was used as a base sheet, and one surface was coated with a PVC-based ink “ka” (Showa Ink Kogyosho) Gravure printing of the pattern with a transparent PVC of 0.2mm thickness
Laminate the sheets (the same), apply a urethane-based adhesive (DIC) on the other side of the base sheet, and compression-mold the decorative sheet so that the adhesive side faces the side opposite to the side that contacts the mold It was arranged on the upper mold surface of the mold. A hot plate having a heater embedded therein was applied to the decorative sheet, heated at a temperature of 130 ° C. for 5 seconds, and vacuum-pressed with a compression mold. A continuous strand mat of glass fiber (fiber content: 40% by weight) and an unsaturated polyester resin were supplied on the lower mold of the compression mold. The upper mold was lowered and kept at room temperature at a pressure of 10 kg / cm ² for 15 minutes to obtain an FRP painted molded product.

Example 2 70 parts of bisphenol resin, 30 parts of solvent and CaCO ₃ powder 1
An SMC (30% by weight of fiber content) was prepared by impregnating a plastic compound consisting of 20 parts into an aggregate of glass fibers having a length of 20 mm. A 0.5mm thick transparent PVC sheet (same as above) is used as a base sheet, and a release agent "BH-3" (manufactured by Showa Ink Industries Co., Ltd.)
Is roll-coated, a pattern is printed with the printing ink "GG" (manufactured by Showa Ink Industries, Ltd.), and the transfer sheet, which is roll-coated with the heat seal material "NC" (manufactured by Showa Ink Industries, Ltd.), is heated to 100 [deg.] C. by a far-infrared heater. Was heated for 10 seconds to soften. The converted inverted sheet was placed on the upper mold surface of the compression mold so that the base sheet side was in contact with the mold, and preformed. Place the above SMC on the lower mold and tighten the mold to a temperature of 150
The mixture was heated and pressed at 100 ° C. and a pressure of 100 kg / cm ² for 10 minutes to obtain a molded article integrated with the transfer sheet. The base sheet was peeled off from the molded product, and a two-component curable urethane resin paint was further applied on the transfer pattern drawing to obtain a FRP molded product having a pattern on the surface.

Example 3 A helmet preform containing 40% by weight of glass fiber was prepared. A 0.5mm thick acrylic resin sheet is used as a base sheet, and a decorative sheet is printed on it with a printing ink “K” (made by Showa Ink Industries Co., Ltd.) and an adhesive is applied.
It was arranged on the upper mold surface of the compression mold so that the substrate sheet side was in contact with the mold. Use this decorative sheet with a surface temperature of 14
A hot plate at 0 ° C. was applied for 20 seconds to soften, and preformed by a vacuum forming method. At the same time, the preform was placed on the lower die of the compression mold, and the unsaturated polyester resin was supplied thereon. The mold was closed and compression molded at a pressure of 500 kg / cm ² to obtain a helmet having a pattern on the surface.

【The invention's effect】

According to the method of the present invention, FRP having a desired beautiful appearance
Can be easily manufactured. Because the surface of the molded product is covered with a sheet for painting,
There is no problem of fiber exposure.

[Brief description of the drawings]

1 to 4 are views for explaining each step of the present invention. FIGS. 1 and 2 show a state where a painting sheet is arranged in a mold, and FIG. Is SMC in the mold
And FIG. 4 is a schematic cross-sectional view showing compression molding. FIG. 5 is a side view showing a part of the FRP-painted molded article manufactured in this manner in a cross section. 1A, 1B: Mold, 11: Vacuum hole 3: Sheet for painting, 4: SMC 5: FRP

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-44414 (JP, A) JP-A-63-162414 (JP, A) JP-A-63-153200 (JP, A) JP-A-2- 26800 (JP, A) JP-A-63-94839 (JP, A) JP-A-1-168541 (JP, A) JP-A-59-38025 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 43/00-43/58

Claims (12)

(57) [Claims] 1. A method in which a pattern printing layer or a metal vapor-deposited layer is provided on a plastic base material sheet on a surface of an upper die and / or a lower die of a compression molding die comprising an upper die and a lower die. Place the sheet for heating, vacuum and / or
Pre-forming the painting sheet by performing pressure forming, then placing the fiber reinforcement and the prepolymer of curable resin on the lower mold, tightening the mold and performing compression molding, the painting sheet is integrated. A method for producing a painted molded product, which comprises obtaining a FRP molded product that has become a finished product. 2. The method according to claim 1, wherein the painting sheet is heated by irradiating heat rays with a far-infrared heater or by contact with a hot plate in which an electric heater is embedded. 3. A positioning mark is provided on a painting sheet, the mark is detected by a sensor provided in the compression molding machine, and the painting sheet is placed at a predetermined position of a mold. 2. Manufacturing method. 4. The method according to claim 1, wherein the compression molding is performed by placing the SMC on a lower mold. 5. The method according to claim 1, wherein the compression molding method is a cold pressing method in which a preform or a continuous strand mat of a fiber reinforcing material is placed on a lower mold together with a prepolymer. . 6. A preform-matched metal die method in which the plastic compression molding is carried out by placing the fiber reinforcement and a curable resin on a preform lower mold.
3. The method according to any one of items 1 to 3. 7. The production method according to claim 1, wherein a decorative sheet having a decorative layer and / or a surface protective layer provided on a plastic base sheet is used as a painting sheet. 8. An uncured ionizing radiation-curable resin layer wherein the surface protective layer of the decorative sheet is semi-cured or touch-dried,
The method according to claim 7, further comprising a step of irradiating a plastic molded article integrally formed with a decorative sheet with ionizing radiation to cure the ionizing radiation-curable resin. 9. The method according to claim 7, wherein the surface protective layer of the decorative sheet is a mat layer to which a bead pigment is added. 10. The method according to claim 7, wherein the decorative layer of the decorative sheet includes a metal deposition layer. 11. The method according to claim 1, wherein the method is performed using a painting sheet to which an adhesive has been applied. 12. The method according to claim 1, further comprising the step of using a transfer sheet as a painting sheet, integrating the transfer sheet, and peeling off the transfer board from the plastic molded product.