JPS6213781Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a hot-press molded article of laminated paperboard having notches.

Hot-press molded laminated paperboard products are used as automobile interior materials and home appliance parts. The molding material for this molded product is laminated paperboard, so if a large tensile stress is applied to the molding material during deep drawing, such as a deep-bottomed molded product, cracks may occur or break at that part. It is not possible to obtain a satisfactory hot-press molded product. Similarly, wrinkles and delamination of the laminated paperboard due to wrinkles occur in areas where compressive stress is applied. For this reason, when deep drawing processing or the like is required, a laminated paperboard with a higher content of virgin fibers than used paper fibers is used to improve formability. However, even if the laminated paperboard is made entirely of virgin fibers, there is a limit to its processability, and in practice it is not possible to obtain a molded product with a deep bottom on which a large stress is applied.

The present invention is a laminated paperboard having a notch and laminated with felt to strengthen the notch and at the same time create a hot-press molded product of the laminated paperboard with a deep bottom. That is, the laminated paperboard hot-press molded product of the present invention includes a laminated paperboard containing a binder with cutouts formed in the areas where compressive stress occurs during molding, and a binder laminated on one or both sides of the parts with the cutouts. It has a certain shape obtained by compressing, heating, and forming a sheet-like felt between at least a pair of heating molds, and has a structure in which the laminated paperboard and the felt are integrated and the notch is closed. That is.

In the hot-press molded product of the present invention, compressive stress does not occur because the portions where wrinkles would occur in conventional deep drawing are notched. In addition, the design of the notch allows consideration to be taken so that large tensile stress does not occur in the molding material, improving moldability and making it possible to provide molded products with a deep bottom, which was previously considered impossible. Note that the notch portion is closed during molding and joined with a bonding agent, and the felt is laminated and compacted to be integrally fixed to the notch portion, making it strong in strength. Therefore, the hot-press molded product of the present invention can not only be a deep-drawn product, but also have better mechanical properties than conventional products. Note that although there is a boundary between the felt part and the paperboard part in the molded product, by adding texture to the surface, painting, or pasting a skin, the boundary disappears and the appearance problem is resolved.

As shown in Fig. 1, the laminated paperboard thermoformed product of the present invention has wedge-shaped cutouts 2 formed in the areas where compressive stress occurs (specifically, the areas where wrinkles occur) during the forming process of the laminated paperboard 1. Use the one you made. The shape, dimensions, and number of these notches are determined by the shape of the molded product, but it is important to ensure that the laminated paperboard does not overlap or wrinkle after hot-pressing, and that the gap between the notches closes after molding. Design so that it can be used. To explain it from a different perspective, a three-dimensional molded product expanded into a two-dimensional shape becomes the laminated paperboard with cutouts according to the present invention. Although it is not possible to accurately develop a 3D shape into a 2D shape,
Since the laminated paperboard itself is deformed and molded during molding, it is only necessary to form the cutouts in the portions exceeding the molding limit of the laminated paperboard itself. Once the finished three-dimensional molded product is developed and a two-dimensional shape with a cutout is determined, the cutout is formed by punching out a regular laminated paperboard. In FIG. 1, when the box-shaped molded product with an open top shown in FIG. 3 is expanded, wedge-shaped notches 2 are required at the corners. A sheet-like felt 3 is placed over the part where the notch is formed. The felt 3 functions to reinforce the notched portion and improve moldability. The felt 3 may be stacked on one side or both sides. Moreover, it is possible to overlap not only the notched portion but also the entire surface.

As the laminated paperboard that is the raw material for the molded product of the present invention, conventional laminated paperboard can be used as is. In other words, the binder such as phenolic resin is about 3%,
Laminated paperboard containing a sizing agent such as acrylic resin can be used. In addition, super absorbent paperboard made only of paper fibers containing no binder or sizing agent is immersed in an aqueous solution of thermosetting resin. Ideal as a devised laminated paperboard. This laminated paperboard is made of adhesive that oozes out on the cutout surface due to heat and pressure.
The incision can be almost completely joined.

Any felt may be used as long as it is made of long fibers that can be entangled by needle punching or the like. Felts made of inorganic fibers such as glass fibers, felts made of natural fibers such as wool, and felts made of polyester, nylon, polyethylene, and polypropylene fibers can also be used.

The binder contained in the laminated paperboard or felt is preferably a thermosetting resin such as a phenolic resin or a melamine resin. The binder content of the laminated paperboard is about 3 to 50% by weight, more preferably 10 to 20% by weight, based on the total weight of 100%. 10-50% by weight for felt, more preferably 20-30% by weight
It is.

In the production of the laminated paperboard thermoformed product of the present invention, the laminated paperboard is compressed and heated between a pair of molds having a fixed interval as in the past, and then formed. , the notch closes as it is pressed between the pair of molds, and when the mold is completely closed, the notch is also almost closed. In this state, heat is applied from the mold to the laminated paperboard and felt, and the pressure and heat cause the binder to integrally bond the paper fibers and felt fibers that are the constituent elements of the laminated paperboard and felt. Join completely. The fibers are then fixed together in the mold, completing the molding.

Next, examples will be shown.

A box-shaped molded body 10 with an open top shown in FIG. 3 was developed two-dimensionally and a laminated paperboard 1 with cutouts 2 formed at the four corners was punched out. This laminated paperboard 1 contains 12% by weight of phenolic resin and has a thickness of 1.6mm ^per square meter.
It weighs 1600g. The back side of the four corners of this laminated paperboard 1 has an L-shaped shape with a thickness of 5 mm and a phenol resin content of 20
Weight%, 400g of felt 2 per 1 m ² is layered,
A composite material, which is a molding material, was obtained. Next, a pair of upper and lower molds with a clearance of approximately 1.6 mm are used to
A laminated paperboard hot-press molded product having a depth of 20 mm as shown in FIG. 3 was produced at 180° C., at a pressure of 3 Kg/cm ² and for a pressing time of 180 seconds.

The corners of this molded product 10 had a structure in which a hot-press molded part 11 of laminated paperboard and a hot-press molded part 12 of felt were integrally joined, as a partial cross-section of the corner part is shown in FIG. Note that the notch was completely closed, and the joint surface was hardly distinguishable. The strength of the molded product 10 was such that it could be used as a hot-press molded product of laminated paperboard without any particular problems.

For comparison, a composite material in which only felt was layered without any notches was used and hot-press molding was performed using the same mold and molding conditions. However, the resulting molded product was extremely fragile in terms of strength, as the laminated paperboard was strongly compressed and the paperboard deteriorated.

[Brief explanation of the drawing]

Fig. 1 is a partial perspective view of a molding material for producing the laminated paperboard thermoformed product of the present invention, Fig. 2 is a partial sectional view of a corner of the laminated paperboard thermoformed product of the present invention, and Fig. 3
The figure is a perspective view of a laminated paperboard thermoformed product of the present invention. In the figure, reference numeral 1 denotes a laminated paperboard, 2 a cutout, 3 a felt, and 10 a hot-press molded laminated paperboard product.

Claims (1)

[Scope of utility model registration request] A laminated paperboard containing a binder with cutouts formed in areas where compressive stress is generated during molding, and a sheet-like felt containing a binder overlaid on one or both sides of the areas with the cutouts are placed between at least a pair of heating molds. A laminated paperboard hot-press molded product, which has a fixed shape obtained by compression, heating, and molding, and has a structure in which the laminated paperboard and felt are integrated and bonded with closed notches.