JPS60127140A - Synthetic resin expanded molded shape having hinge function - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a technique for imparting a bendable hinge function to a synthetic resin foam molded article.

Conventionally, a method for imparting bendability to a synthetic resin foam is to laminate a flexible sheet material made of synthetic resin or fabric on the upper and lower surfaces of a rigid or semi-rigid synthetic resin foam plate, and to obtain the desired shape. Either the upper and lower seams 1 to 1 are integrated by sewing or fusing the materials without intervening synthetic resin foam, or thermoplastic resin foam such as polyvinyl chloride foam is used as a synthetic resin foam. Methods such as laminating it with a synthetic resin film and subjecting it to high-frequency fusion processing to form recesses have been used.

However, the method of integrally fusing the sheet material and the sandwich structure is suitable for molding a simple flat shape, but it is difficult to mold a three-dimensional shape with partially different thicknesses. It is difficult, and there are disadvantages such as molding defects easily occurring due to sparks etc. during high frequency welding.In addition, there are also problems such as variations in product life due to thermal deterioration of the material and synthetic resin foam. It has the disadvantage of requiring extra steps such as cutting and fusing.

On the other hand, when molding flexible polyurethane foam, a recess is formed in the part that requires bending, and a porous material such as foam or nonwoven fabric is used as a partition material in the recess, or a porous material such as metal or plastic is used as a partition material. The technique of integrally embedding and foaming using a rigid body is well known (Utility Model Publication No. 56-2791).
No. 8), but in this method, an open-cell foam or a fiber entangled body such as non-woven fabric or palm rock is interposed throughout the thickness of the recessed part to serve as a partitioning material.

This allows different types of foaming urethane stock solutions to be injected and foamed into both cavities that make up the back and seat parts of the cushion, thereby preventing inconveniences caused by urethane foams with different hardnesses mixing with each other during the foaming stage of different blended stock solutions. The aim is to obtain a composite foam with a high temperature.

Therefore, the partition material used in this method must have a thickness and a dense structure that allows the urethane foaming stock solution to penetrate, but not allow it to pass through and mix with the urethane foaming stock solution of a different composition. It is necessary to use materials.

In addition, the composite molded product obtained in this case has the disadvantage that unless it is covered with a strong outer material such as cloth or leather, it has poor bending durability and cannot be made very thin.

The present application solves these shortcomings and is designed to be used in applications that are bent and used repeatedly hundreds to thousands of times a day, such as cover lids for copying machines, etc., without being covered with an external material. The present invention provides a method that makes it possible to provide a hinge function that exhibits excellent durability.

That is, when molding a hinge mechanism made of thin synthetic resin foam that can be folded and bent, a protrusion is provided on the mold so that a groove is formed in the part where the bending function is desired, and a small amount is formed at the bottom of the groove. The spacing between yarns in one direction, both vertically and horizontally, is 0.05-1 mm, preferably 0.1-0.
A reinforcing cloth woven to a length of 5 m was placed in a mold so that it could be buried discontinuously in the longitudinal direction of the groove, which was larger than the width of the hollow groove, and foam molded with synthetic resin. A synthetic resin foam molded article having a groove bottom is obtained.

The high-density skin layer embedded in the thin reinforcing fabric formed in this way has extremely high bending durability and has a
No abnormalities were shown after continuous bending over 00,000 times.
Even when the molded product was left for a long time, there was no appearance defect such as shrinkage.

Examples of the synthetic resin foam used in this application include polyurethane foam whose raw material is liquid, natural and synthetic latex foam, and polyvinyl chloride foam.

In addition, if it is desired to make the adhesiveness with the reinforcing cloth stronger, a pretreatment such as applying an appropriate adhesive or treatment agent to the extent that it does not block the mesh of the reinforcing cloth may be performed.

There are no particular restrictions on the material for the reinforcing cloth used in this application;
It may be a natural fiber, a synthetic fiber, or a synthetic fiber. In addition, they may be used in combination as appropriate.

What is important in this application is that the synthetic resin 1 has pores that can penetrate under conditions such as pressurization and heating.

For example, in the case of woven fabric, the spacing between yarns is 0.05 to 1 field.
It is sufficient to use a fabric with a somewhat sparse number of stitches in the range of
The purpose of the present application can be achieved by providing a small hole with a diameter of ~1 m.

If the spacing between the remaining yarns becomes too large, it is not preferable because a texture will appear on the outside when the synthetic resin is integrated with the thin wall.

Furthermore, it is necessary to increase the reinforcing effect of the thin groove bottom by making the buried reinforcing cloth wider than the groove width of the groove formed in the synthetic resin foam.

Furthermore, the reinforcing fabric should not be buried in the entire longitudinal direction of the thin groove bottom, but should be disposed discontinuously.

This is because if buried in the entire groove bottom, there will be a difference in molding shrinkage rate between the thin groove bottom where the reinforcing fabric is integrated and the other areas where thick reinforcing fabric is not present, so the molded product will gradually become distorted. It is. In addition, the reinforcing cloth impregnated with synthetic resin has significantly higher density and rigidity than a portion made of foam alone, so that even if it is thin, it will inhibit free bending.

It is desirable that the thickness of the groove bottom of the recessed groove in the desired bending portion is not too thick.

This thickness should be selected in relation to the density and thickness of other parts of the molded body, but in general, the groove thickness is 0.05 to 0.00 mm for each thickness of the flat plate portion of the molded body. 4 preferably 0.
It is in the range of 1 to 0.3.

Further, it is preferable that the groove width is 4 or more times the thickness of the flat plate portion of the molded body. The thickness of the groove bottom may be uniform over the entire width of the groove, but it may also be set so that the thickness differs in one part.

However, even if the thickness is partially changed, the thickness must be the same in the longitudinal direction of the groove, otherwise the bendability will be affected.

If it is desired to maintain the folded state at an angle of around 90° when the molded product is bent, it is preferable to provide a portion where the foamed molded products come into contact with each other on the side surface portions forming the tf.

Examples will be described based on the drawings. As shown in FIG. 1, the flat plate part (1) of the molded body is provided with a thick wall part (2), and the thick wall part has protrusions (3) (3) at both ends thereof.

On the other hand, both ends of the flat plate part (1) on the concave groove (4) side have (
3) Provide a notch corresponding to (3).

When the flat part (1) is bent at 90 degrees, the flat part (1)
) side protrusions (3) (3') side parts (a) and (b)
If it is selected so that it comes into contact with the side parts (A') (mouth') of the notch on the flat plate part (1) side with a slight compression, the flat plate part (1) ) is the second
As shown in the figure, it can be kept stationary in a bent position of about 90 degrees.

In this example, the thickness of the groove bottom is 1 mm, and the groove width is 81 m +
, molded with a semi-rigid polyurethane integral skin foam with a thickness of 7 in the flat plate part and 10 nwn in thickness in the thick part, and a plain woven nylon cloth as a reinforcing cloth with a weaving yarn spacing of 0 in both length and width.
A piece measuring 4 m was cut into a longitudinal shape with a width of 15 nxn and a length of 30 fields, and was discontinuously buried in three locations at both ends and approximately in the center of the trench.

FIG. 3 shows another embodiment of the present application, in which a thick interior (2) is provided in the same manner as in FIG. This is an example of a case where a notch corresponding to the part is not provided.

In this case, as shown in Figure 4, when bent over 90 degrees, (1) does not stand still, so bend it over 90 degrees so that the thick inner part (2) comes into contact with the flat part (1). It becomes stationary at the stage where it is.

Incidentally, FIG. 5 shows a sectional view taken along line XX in FIG. 3.

As in the case of FIG. 1, it is molded from a semi-rigid polyurethane integral skin foam.

Figures 6 and 7 show another embodiment in which the bending is at an angle of 180°; in this case, the groove width is the total dimension of the thickness of each of the flat plate parts (1) and (1). The thickness of the groove bottom was required to be at least 2 m or less, regardless of the thickness of the flat plate portion (1) (1).

In all cases, the molded bodies thus obtained showed no cracking or breakage even after being repeatedly bent 100,000 times at room temperature.

Furthermore, since the foam has a skin layer on one surface, it is possible to color the foam to a desired color, thereby resulting in a beautiful molded product that can be used without using an external material.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of the present application, FIG. 2 is a side view showing the molded body of FIG. 1 in a folded state, FIG. 3 is a perspective view showing another embodiment of the present application, and FIG. The figure is a side view showing the molded product shown in FIG. 3 in a folded state, FIG. 5 is a sectional view taken along line X-X of the molded product shown in FIG. 3, and FIG. 6 shows yet another embodiment of the present application. Side view, FIG. 7 is a side view showing the molded body of FIG. 6 in a folded state. 11': Flat plate portion 2: Thick wall portion 3.3: Protrusion portion 4: Hollow groove portion 5: Reinforcement fabric Patent applicant: Toyo Tire & Rubber Industries, Ltd.

Claims (2)

[Claims] (1) When creating a groove-like depression in the desired bending part of the synthetic resin foam, a thin, high-density skin layer is formed at the bottom of the groove by embedding and integrating reinforcing fabric that is larger than the width of the groove and is discontinuous in the longitudinal direction. A synthetic resin foam molded article having a hinge function. (2) The hinge according to claim 1, characterized in that the reinforcing cloth buried in the groove bottom is a sparsely implanted cloth material that can be penetrated by a synthetic resin under pressure and/or heat. A synthetic resin foam molded body with functions.