JP2831251B2 - Wood fiberboard for press forming - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wood-based fiberboard for press molding which has improved molding accuracy by preventing deformation and dimensional change after molding.

[0002]

2. Description of the Related Art Conventionally, as automotive interior parts such as an automobile door trim and a rear corner trim to be installed in an automobile body panel, as shown in FIG. 2, a molded part having a desired curved surface shape is formed. Although not shown in FIG. 2, the core material 1 generally includes a skin material that covers the outer surface of the molded core material 1.

In recent years, a molded core material 1 constituting a core material of a door trim is formed into a complicated three-dimensional shape in terms of molding, for example, by swelling a substantially central portion toward a vehicle interior to form an armrest 2. There is a tendency.

A wood fiberboard is generally used as a material of the molded core material 1. The wood fiber board is made of wood fiber, cotton yarn, thermosetting resin (having a melting point of about 200 ° C.), It is composed of paraffin and the composition distribution is as shown in Table 1 below.

[0005]

[Table 1]

[0006]

However, the wood fiberboard of the conventional composition distribution is light and inexpensive, but is inferior in moldability and easily deformed or changed in size after molding. ing.

That is, as shown in FIG. 2, in order to attach a weather strip (not shown), the upper end edge of the molded core 1 is bent downward, but the bent portion is deformed to the position shown by the broken line in the figure. It has also been pointed out that it is difficult to hold the weatherstrip in an appropriate position, which hinders smooth lifting and lowering of the window glass.

As described above, the causes of deformation and dimensional change of the conventional wood fiberboard after molding are influenced by humidity, and as shown in the graph of FIG. The inventors have found that the rate of change is approximately proportional.

The present invention has been made in view of such circumstances, and provides a wooden fiberboard with improved dimensional accuracy by preventing deformation and dimensional change of the wooden fiberboard due to the influence of humidity. It is intended to be.

[0010]

In order to achieve the above object, a wood fiber board for press molding according to the present invention comprises mixing wood fiber, cotton yarn, thermosetting resin having a melting point of about 150 ° C., and paraffin. It is characterized in that thermoplastic resin fibers having a melting point of around 180 ° C. are entangled on the front and back surfaces of the mat formed by dispersion.

[0011]

As is apparent from the above constitution, the wood fiber board for press molding according to the present invention has thermoplastic resin fibers entangled on the front and back surfaces of the mat. Moisture absorption from the side can be prevented as much as possible.

Further, in the secondary processing of a wood fiber board, when a skin material is adhered to the surface of the molded core material by vacuum molding or the like, if the surface side of the molded core material is heated, the thermoplastic resin fibers are melted. Since the thermoplastic resin fiber functions as an adhesive medium, the conventional adhesive and the step of applying the adhesive can be eliminated.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a wood fiber board for press molding according to the present invention will be described below.

FIG. 1 is a cross-sectional view showing the structure of a wood fiber board 10 for press molding according to the present invention. The wood fiber board 10 for press molding according to the present invention has thermoplastic resin fibers on both sides of a mat 11. 12 are entangled.

More specifically, the mat 11 is almost the same as the conventional mat configuration shown in Table 1, and the mixing ratio of wood fiber, cotton yarn, thermosetting resin, and paraffin is also shown in Table 1.
Is the same as

However, the mat 11 used for the wood fiberboard 10 for press molding according to the present invention has a melting point of 15
A thermosetting resin at about 0 ° C. is used.

Further, as the thermoplastic resin fiber 12 to be entangled on the front and back surfaces of the mat 11, a polypropylene resin fiber is used in the present embodiment because the cost and the desired melting point are close.

The melting point of the polypropylene resin fiber is 1
It is around 80 ° C.

As described above, in the wood fiber board 10 for press molding according to the present invention, the thermoplastic resin fibers having a melting point of about 180 ° C. are entangled on the front and back surfaces of the mat 11 in order to improve the moisture resistance. Therefore, deformation and dimensional change after molding can be minimized.

Next, as a molding condition of the wood fiber board 10 for press molding according to the present invention, a hot press molding method is used as in the prior art. Is higher than the melting point of the thermosetting resin (150 ° C. in the present embodiment), and the thermoplastic resin fibers 12 set on the front and back surfaces of the mat 11 are made of thermoplastic resin so as not to adhere to the mold surface. It is necessary to set lower than the melting point of the resin fiber 12.

Therefore, the mold temperature of the hot press molding die used for the wood fiber board 10 for press molding according to the present invention may be set at around 160 ° C.

Further, the advantage of the wood fiber board 10 for press forming according to the present invention is that the core fiber is formed by using the wood fiber board 10 for press forming according to the present invention, and then the surface of the formed core fiber board is formed. When a skin material such as a synthetic resin sheet is adhered to the mat 11 by vacuum molding or the like, the thermoplastic resin fiber 12 set on the surface of the mat 11 can be used as an adhesive medium, so that the adhesive which was conventionally required can be eliminated, and There is an advantage that the cost of the material can be saved and the cost can be reduced by labor saving of the process, for example, since the step of applying the agent is not required.

[0023]

As described above, according to the present invention, the following special effects can be obtained.

(1) The wood fiberboard for press molding according to the method of the present invention has a structure in which thermoplastic resin fibers for improving moisture resistance are entangled on the front and back surfaces of the mat. The dimensional change can be prevented as much as possible, and the dimensional accuracy can be greatly improved.

(2) Since the wood fiber board for press molding according to the present invention has a structure in which thermoplastic resin fibers are entangled on the front and back surfaces of the mat, the wood fiber board according to the present invention is formed after molding. If the surface is heated, thermoplastic resin fibers can be used as an adhesive medium.Therefore, there is no need to apply an adhesive when vacuum-applying a skin material to the surface of a fiberboard, as in the past, and material costs and man-hours Therefore, there is an effect that the number of man-hours at the time of attaching the skin material can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a wood fiberboard for press molding according to the present invention.

FIG. 2 is a cross-sectional view showing a molded core material of a door trim by molding a conventional wood-based fiberboard.

FIG. 3 is a graph showing a correlation between a moisture absorption rate and a dimensional change rate.

[Explanation of symbols]

 Reference Signs List 10 wood fiber board for press forming 11 mat 12 thermoplastic resin fiber

Claims (1)

(57) [Claims] 1. A thermoplastic resin fiber having a melting point of about 180 ° C. is entangled on the front and back surfaces of a mat formed by stirring and dispersing a wood fiber, a cotton yarn, a thermosetting resin having a melting point of about 150 ° C., and paraffin. A wood-based fiberboard for press molding, characterized in that: