JPH0247343B2 - PANERUSEIKEIBUTSUNOSEIZOHOHO - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a panel molded product that is used, for example, as an interior base material for automobiles. Reinforced structural paper materials such as cardboard have traditionally been used as interior base materials for automobiles. Although cardboard is desirable as a base material for automobile interiors because it is inexpensive and lightweight, it has poor shape retention when molded into a predetermined shape, and its shape is significantly distorted, especially at high temperatures. In order to improve these drawbacks, a method has been proposed in the past in which corrugated cardboard is impregnated with or coated with a thermosetting synthetic resin such as a phenol resin, or a thermoplastic synthetic resin such as polyethylene or polypropylene. However, phenolic resin has a curing temperature of 180° C. or higher and requires high-temperature pressing during molding, so it is not desirable from an energy-saving perspective, and there is a risk that the paper quality may deteriorate. In particular, it becomes impossible to polymerize thermoplastic sheets, foams, felt, etc. that do not have heat resistance to the cardboard and integrally mold them together with the cardboard. Furthermore, since thermoplastic synthetic resins have poor heat resistance and strength, only cardboard with low molding stability and low structural strength can be obtained. The present invention aims to improve the above-mentioned conventional drawbacks and obtain a reinforced structural paper material molded product with excellent shape retention through low-temperature molding. do. The invention will be explained in detail below. The reinforced structure paper material used in the present invention has a structure in which covers 2, 2 are pasted on both sides of a corrugated core paper 1 as shown in FIG. 1, and a cover on one side of the corrugated core paper 1 as shown in FIG. 2, or a structure in which a honeycomb 1' is formed between the covers 2 and 2 as shown in FIG. 3. Phenol resin, urea resin,
It may be impregnated with melamine resin or the like. The urethane prepolymer used in the present invention is a long-chain compound having two or more OH groups such as polyethylene glycol, polypropylene glycol, or polyester, and a polyvalent isocyanate compound such as methylene diisocyanate or tolylene diisocyanate. OH groups are produced by reacting adducts of polyvalent isocyanate compounds with polyvalent alcohols such as ethylene glycol and glycerin, and polyvalent amines such as methylene diamine and phenylene diamine.
Refers to those converted to NCO base. The urethane prepolymer is usually provided as a solution in an organic solvent free of active oxygen, such as toluene, xylol, methylene chloride, trichloroethylene, ethyl acetate, butyl acetate, etc. Both sides are coated with a spray, roll coater, knife coater, curtain flow coater, etc., or impregnated by a dipping method, etc., and if desired, dried at a temperature higher than the boiling point of the solvent. The amount of urethane prepolymer applied or impregnated is 20 to 100.
It should be about g/ ^m2 . If desired, the reinforcing structure paper material may be coated with a wrinkle-removal material such as a non-woven fabric, a fiber-woven knitted fabric, felt, or a plastic foam, a non-woven fabric, a fiber-woven knitted fabric, a plastic sheet, or a polymerization of a plastic sheet and a plastic foam. A surface material such as a surface material for objects etc. may be attached. Adhesion of the surface material does not require any particular adhesive as long as it is done before the urethane prepolymer coated or impregnated on the reinforced structure paper material hardens. However, if the urethane prepolymer alone has low initial adhesive strength, Considering that moisture or the curing catalyst cannot reach the urethane prepolymer of the reinforced structural paper material, it is desirable to use an adhesive having a curing catalytic effect to bond the reinforced structural paper material and the cover material. Adhesives with curing catalytic action are made of synthetic resins containing functional groups with active hydrogen, such as amino groups, amide groups, carboxyl groups, and hydroxyl groups. If so, the adhesive cures integrally with the urethane prepolymer. Of course, a compound containing active hydrogen, such as an amine, an acid amide, an organic acid, or an alcohol, may be mixed as a curing catalyst into an adhesive made of a synthetic resin that does not contain a functional group containing active hydrogen. It is possible to supply moisture or curing catalyst to the urethane prepolymer through the surface material without using an adhesive, especially if the material is porous.
However, the surface material may be denatured by moisture or the curing catalyst, and an extra step is required to dry the material containing moisture or the curing catalyst. The reinforced structure paper material coated or impregnated with the urethane prepolymer is thus molded by pressure molding alone or together with the surface material. The urethane prepolymer is cured by bringing moisture or a curing catalyst into contact with the reinforced structural paper material immediately before molding, or by introducing steam, steam containing a curing catalyst, water, or curing catalyst liquid through holes provided in the mold surface of a pressing mold. It is caused by ejecting and molding. If desired, the reinforced structure paper material coated or impregnated with a urethane prepolymer may be polymerized with the anti-wrinkle material, and then the facing material may be polymerized and integrally formed. The wrinkle removing material is used to prevent wrinkles generated on the surface of the deep-drawn portion of the reinforced structure paper material from appearing as unevenness on the surface of the product. The thus obtained panel molded product has extremely good shape retention and also has high structural strength. Embodiment As the reinforced structure paper material 10, a corrugated cardboard with surfaces 2, 2 attached to the surface of a corrugated core paper 1 impregnated with a phenol resin is used. As the urethane prepolymer, polyethylene glycol (degree of polymerization 3000) reacted with tolylene diisocyanate (40% methylene chloride solution) is used. The material used is thermoplastic felt using polyethylene as an adhesive. Acrylic synthetic resin containing amino groups (15% propylene dichloride solution) is used as the adhesive. In FIG. 4, urethane prepolymer is applied to both sides of a cardboard box 10 using roll coaters 11A and 11B, and then adhesive is applied to one side of the cardboard box 10 using a spray gun 12.
Thermoplastic felt 14 pulled out from roll 13 is crimped onto it by roll 15, and cutter 1
6 to a predetermined size to obtain a panel 10A. Next, in FIG. 5, the upper mold 17A and the lower mold 17
The panel 10A is placed on a pressing die 17 made of B, and press-molded into the shape of an automobile ceiling. At this time, about 4 to 5 kg/m ² from the hole 17' on the mold surface of the lower mold 17B,
Steam at about 130°C is jetted out, and the mold surface of the upper mold 17A is also heated to about 130°C. Press pressure is 3-4
Kg/m ² and press time is about 10 seconds. Thus, the panel 10 consisting of the reinforced structural paper material 10 and the facing material 14 is constructed.
A is integrally molded. Reinforced structural paper material during forming 1
The urethane prepolymer No. 0 is cured by steam and adhesive from the lower mold 17B. The thus obtained automobile ceiling base material sample is extremely lightweight at 700 g/m ² . The results of the thermal cycle test of the above sample are shown below. Sample 20 is subjected to the following thermal cycles. (1) 50℃ 100%RH 8hrs (2) 80℃ Normal humidity 3hrs (3) −30℃ 〃 3hrs The process of (1)→(2)→(3) is one cycle. The sample 20 is deformed as shown by the dotted line in FIG. 6 by the above thermal cycle test. The degree of deformation h is shown in Table 1.

【table】

[Table] According to Table 1, the sample of this example has even better shape stability than Control 1, which uses untreated cardboard, as well as Control 2, which uses phenol resin-reinforced cardboard.

[Brief explanation of the drawing]

Figures 1 to 3 are side sectional views of reinforced structural paper materials with various structures, and Figure 4 is a process diagram before press molding;
FIG. 5 is a process diagram during press molding, and FIG. 6 is a side sectional view showing the amount of deformation in a thermal cycle test. In the figure, 10... Reinforced structure paper material, 14... Covering material.

Claims (1)

[Claims] 1. A reinforced structure paper material is coated with or impregnated with a urethane prepolymer, and moisture or a curing catalyst is applied to the urethane polymer, and the paper material is press-molded into a desired shape. Method for manufacturing panel moldings. 2 Coating or impregnating urethane prepolymer on both sides or one side of the reinforced structure paper material, contacting both sides or one side with a surface material, applying moisture or a curing catalyst to the urethane polymer, and forming the desired shape by press molding. A method for manufacturing a panel molded product, characterized by molding it into a shape. 3. In claim 2, the reinforced structure paper material and the surface material are bonded together with an adhesive having a curing catalytic action of a urethane prepolymer.