JPH0483612A - Cast molding method of resin molded product - Google Patents

Abstract

PURPOSE:To reduce an operation manhour by casting a resin material within a cavity, by constituting the cavity so that preformed fiber aggregate is set up to a top force of a mold, to which a bottom force is clamped and a vacant area is formed on the underrurface of the fiber aggregate. CONSTITUTION:A hole 3 is formed into a position corresponding to the fringe of a bathtub A in a top force 1, a preformed fiber aggregate 4 abuts against the surface of the top force 1, an end part of the fiber aggregate 4 is put between the top force 1 and pad material 5 which is made of resin, a pin 6 is inserted into the hole 3 and the fiber aggregate 4 is set up to the surface of the top force 1. The top and bottom forces 1, 2 are clamped, a cavity having a form of the bathtub A is formed, which is filled with a resin material by casting the same. The resin is infiltrated into the fiber aggregate 4 and a resin layer 7 is formed in a vacant area. The same is taken out from within a mold, the tip of the pin 6 is cut off and the same becomes a finished bathtub A.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an improvement in the method of molding a resin molded article, and aims to integrate a fiber aggregate as a reinforcing material with the resin in the mold. This method is suitable for obtaining a molded product having a resin layer with depth and texture.

(Prior art) The commonly used molding method for resin molded products is to sandwich a glass fiber aggregate between upper and lower molds, clamp the mold, and then fill it with resin by injection etc. It is impregnated into a glass fiber aggregate and cured to form a formed product.

In this case, since the glass fiber aggregate is generally arranged over the entire wall thickness of the molded product, a thick layer of only resin is not formed on the surface of the molded product.

In recent years, from an aesthetic point of view, a layer that maintains the structural strength of the molded product has been placed on the so-called back side of the molded product, and the surface side of the molded product has only a thick resin layer to create a deep and textured product. , or molded products that provide a sense of transparency have become desired.

For example, in recent years, high-class bathrooms have appeared, and in the bathtubs used there, the fiber aggregate, which is a structural strength-retaining layer, is concentrated on the back side of the bathtub, and the surface is made of resin. Bathtubs with a rich texture have become popular.

However, it is difficult to form this resin-rich layer using the very common injection method described above.
A special method was used.

That is, first, a fiber aggregate forming a structural strength-retaining layer is impregnated with a resin by a hand lay-up method or the like to preform a reinforcing layer that will be the back side of the molded product.

Then, this preformed reinforcing layer is set in a mold, and a resin layer is formed on the surface side by an injection method, or after the resin layer is formed, a reinforcing layer is formed by a spray-up method. .

When forming this resin layer, air is inevitably drawn in, and if the reinforcing layer is formed on the lower side, that is, the resin layer is on the upper side, such air bubbles will rise to the surface of the resin layer, which is completely unfavorable in terms of appearance. Become.

Therefore, in a mold for forming, it is particularly desirable to
Preparations must be made so that a reinforcing layer is placed on the upper mold surface and a resin layer is formed on the lower mold surface.

FIG. 5 is a schematic vertical cross-sectional view showing the relationship among the mold, reinforcing layer, and resin layer in this case. In the figure, reference numeral 21 denotes a reinforcing layer in which a fiber aggregate formed by hand lay-up is impregnated with resin in advance, and this is adsorbed to the upper mold 1 by vacuum. Next, after closing the lower mold 2, a resin material is filled into the cavity of the mold by an injection method.

As a result, the resin and the reinforcing layer 21 are integrated, and a resin-rich layer 22 is formed on the surface side of the molded product.

At this time, air bubbles caught in the resin material are removed from the resin layer 2.
2 and the reinforcing layer 21, and temporarily does not exist on the surface of the resin layer 22.

(Problems with the prior art) However, according to this molding method, the reinforcing layer has to be prepared in advance in a separate process, which requires a lot of man-hours. It is necessary to use a large-capacity vacuum to hold the entire layer, and there are many points that need to be improved, such as increased man-hours and costs.

In addition, air bubbles that are caught up with the resin material have no place to escape and remain visible from the surface, resulting in aesthetic problems.

Furthermore, the resin constituting the reinforcing layer and the resin to be filled are not completely the same material, resulting in problems at this interface.

(Purpose of the present invention) The purpose of the present invention is to improve the above-mentioned problems, and it is possible to reduce the number of work steps, and also to form a resin layer with a sufficient thickness, and furthermore, to prevent it from getting caught up in the resin material. To provide a method for obtaining an excellent molded product that also absorbs air bubbles.

(Solution Means) In order to achieve the above object, the present invention employs the following configuration.

That is, a fiber aggregate preformed into a predetermined shape is set in an upper mold of a forming mold, and a lower mold is clamped to this to form a cavity in which an air space is formed on the lower surface of the fiber aggregate, An injection molding method for a resin molded article, characterized in that a resin material is then injected into the cavity to impregnate the resin into the fiber assembly, and a resin layer is formed in the air space, preferably the fiber The aggregate is preferably a non-woven body such as a continuous strand mat or chopped strand mat, or a woven body such as glass cloth or carbon cloth, while the resin is preferably an acrylic resin or an unsaturated polyester resin.

In this invention, as a molding method particularly applied to bathtubs, etc., a recess is formed on the surface of the upper mold corresponding to the support leg of the molded product obtained, and the preformed fibers are inserted into the recess along with the insert part. The aggregate is set on the upper mold surface, and then the lower mold is clamped to form a cavity with a predetermined air space on the lower surface of the fiber aggregate.Then, the cavity is filled with a resin material to inject the resin into the fiber aggregate. A method of forming a resin molded article is preferably used, which is characterized in that the insert part is also impregnated with resin, and the air space is further filled with the resin to form a resin layer.

(Function) In the molding method of the resin molded product of the present invention, the preformed fiber aggregate is set on the upper mold surface where air bubbles are likely to occur, so the air bubbles are absorbed and become completely invisible. In general, the resin layer of the molded product is formed on the surface side of the lower mold, which has the property of forming a dense surface of the molded product, and the thickness of the resin layer can be adjusted by setting a desired distance between the two molds. This means that you can adjust the brightness.

Therefore, a molded product with a thick resin layer that has a textured and transparent appearance can be obtained, and the layer that maintains the strength of the molded product is concentrated on the back side of the molded product. It is something.

And since this reinforcing layer is formed at the same time as the resin molding and curing, there is no need for preforming (it also has a great effect on reducing the number of work steps).

In addition, in order to obtain a transparency and texture that looks like marble, the thickness of this resin layer should be 3 mm or more, preferably 10 m.
It is desirable to set it to m or more.

(Specific Example) Hereinafter, the present invention will be explained in more detail using an example of molding a bathtub.

FIG. 1 is a main cross-sectional view of bathtub A during molding based on the molding method of the present invention, in which 1 shows the upper mold and 2 shows the lower mold.

In the upper mold 1, a hole 3 is formed at a location corresponding to the edge of the bathtub A, and the preformed fiber aggregate 4 is brought into contact with the surface of the upper mold 1, and then the fiber aggregate is removed using a resin-made contact member 5. 4, and then insert the bottle 6 into the hole 3.
to set the fiber aggregate 4 on the surface of the upper mold 1.

Then, the upper and lower molds 1.2 are clamped to form a cavity in the shape of a bathtub A, and a resin material is injected and filled into this cavity.

This cavity provides an air space of approximately 10 mm between the fiber assembly 4 and the surface of the lower mold 2.

The resin material used here is an unsaturated polyester resin, and this resin is impregnated into the fiber aggregate 4 and forms the resin layer 7 in the above-mentioned air space.

Of course, the above-mentioned material 5 is similarly surrounded by resin and made into an integral molded product, and is then taken out from the mold and the tips of the pins 6 are cut to form the completed bathtub A.

FIG. 2 shows a partial sectional view of the bathtub A.

As you can see in this figure, the surface of the molded bathtub A is 1
It is a single resin layer 7 with a thickness of 0 mm, and the fiber aggregate 4 is impregnated with resin on the back side thereof to maintain strength.

The finished product has the material 5 buried in the resin layer 7 at the edge of the bathtub A.

FIG. 3 shows a second example of obtaining a bathtub B by the molding method of the present invention, in which a recess 8 is formed in the upper mold 1 at a location corresponding to the leg of the bathtub B, and a bottle hole 9 is formed in this. There is.

Then, the insert material 10 is fitted into the recess 8, and the tip 11 of the insert material 10 is inserted into the bottle hole 9 and held.

Next, the preformed fiber aggregate 4 is placed in an upper mold l.
The screw 12 is inserted into the assembly 4 while supporting it.
etc., to penetrate this assembly 4 and fix it to the insert material 10.

In this case, the fiber aggregate 4 and the insert material 10 are fixed in advance with screws 12, etc., and then the insert material 1
It is also possible to insert and hold the tip 11 provided in the bottle hole 9 into the bottle hole 9.

Then, holding the lower mold 2, the fiber aggregate 4 is
A predetermined air space (distance 10 mm) between the upper mold 2 and the lower mold 2
to form a cavity.

Next, a resin material is injected into this cavity to impregnate the fiber assembly 4 with the resin, and the resin also surrounds the insert material 10, thereby integrating the entire structure.

On the other hand, the air space is filled with this resin material to a thickness of 10 mm.
A bathtub B having the resin layer 7 is completed.

FIG. 4 shows a sectional view of the vicinity of the legs of this bathtub B.

In this manner, in the second embodiment, the insert material 10 is used as it is as a structural reinforcement for the leg portion.

In this second embodiment, the insert material 10 is shaped approximately like the leg of the bathtub B, and the surface of the insert material 10 is depressurized by a vacuum provided in the upper mold 1 to be placed inside the recess 8 of the upper mold 1. It is also a good method to adsorb the fibers and set the fiber aggregate 4 thereon.

(Effects) As described above, according to the present invention, the fiber aggregate that serves as the reinforcing layer of the molded product and the resin layer that gives the product texture etc. are separated from each other in terms of the structure of the molded product. Moreover, during molding, it is sufficient to simply set a preformed fiber aggregate in the upper mold and fill it with resin material, which simplifies the molding process.

Furthermore, since only one type of resin material is used in the molded product, the quality of the molded product is stable, there are no defects at the interface between resins that would occur with conventional methods, and air bubbles that are drawn in with the resin material are eliminated from the fiber aggregate. As a result, the defect rate of molded products has become extremely low.

[Brief explanation of the drawing]

FIG. 1 is a main cross-sectional view of bathtub A when it is formed by the molding method of the present invention, FIG. 2 is a partial cross-sectional view of bathtub A, and FIG. FIG. 4 is a cross-sectional view of the vicinity of the legs of the bathtub B, and FIG. 5 is a schematic longitudinal cross-sectional view showing the relationship between a mold, a reinforcing layer, and a resin layer according to the prior art. 3... Hole, 4... Preformed fiber aggregate, 5...
...Material, 6...Bin, 7...Resin layer, 8...Recess, 9...Bin hole, 10... ...Insert material, 11-... Tip, 12... Screw. Patent applicant Brideston Co., Ltd. A, B...Bathtub, 1...Upper mold, 2...Lower mold, Fig. 1 Fig. 2

Claims (4)

[Claims] (1) A fiber aggregate preformed into a predetermined shape is set in the upper mold of a forming mold, and a lower mold is clamped to this to form a cavity with an air space formed on the lower surface of the fiber aggregate. An injection molding method for a resin molded product, characterized in that a resin material is then injected into the cavity to impregnate the resin into the fiber assembly, and a resin layer is formed in the air space. (2) The injection molding method for a resin molded product according to claim 1, wherein the fiber aggregate is a nonwoven body such as a continuous strand mat or chopped strand mat, or a woven body such as glass cloth or carbon cloth. (3) The injection molding method for a resin molded article according to claim 1, wherein the resin is an acrylic resin or an unsaturated polyester resin. (4) Form a recess on the upper mold surface corresponding to the support leg of the molded product to be obtained, set the preformed fiber aggregate together with the insert part in the recess on the upper mold surface, and then place the lower mold on the upper mold surface. The mold is clamped to form a cavity with a predetermined air space on the lower surface of the fiber assembly, and then a resin material is filled into the cavity to impregnate the fiber assembly with the resin, and the insert part is also surrounded by the resin. A method for molding a resin molded product, further comprising filling the air space with resin to form a resin layer.