JPH05305616A - Simple mold for molding of plastic - Google Patents

Abstract

PURPOSE:To constitute the title mold so that an air gap such as a pin hole is not generated in a molding surface of the mold, by a method wherein the surface of a bottom force and/or a top force of the mold for FRP molding is made into a metallic plate and a metallic layer having the low melting point is provided as a backing layer of the metallic plate. CONSTITUTION:A simple mold suitable for molding of fiber-reinforced plastic by casting and solidifying a liquid thermosetting resin material is constituted of a bottom force and top force. In a mold like this, the surface of the bottom force and/or the top force is made into a metallic plate 1 and a metallic layer having the low melting point is provided as a backding layer of the metallic plate. A mild steel plate such as rolled steel plate or aluminum or stainless steel is used as the metallic plate 1 and molded into a form of a molded matter within a range of a thickness of 0.2mm-10mm by sheet metal processing or press processing. Then the backing layer is formed of a laminated body of a zinc metal flame sprayed layer 2 of the metallic layer having the low melting point, an epoxy resin layer 4 containing aluminum powder of thermosetting resin containing metallic power and a foaming urethane layer 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a thermosetting resin material in a liquid state and hardens it to mold a fiber reinforced plastic (hereinafter abbreviated as FRP). Regarding molds.

[0002]

2. Description of the Related Art Conventionally, a mold having excellent heat resistance, durability and dimensional accuracy has been generally used as a mold for FRP. However, due to the recent diversification of market needs,
High-mix low-volume production is unavoidable, and when molds are used, the mold cost accounts for a large proportion of the molded product cost in the low-volume production of several thousand units / month.

Therefore, a mold that can be manufactured in a short period of time, has high durability, and is inexpensive is required. At present, there are simple molds such as resin molds and electroforming molds for such requirements, but these simple molds have large dimensional changes over time, cannot be heated, and are difficult to dispose as industrial waste. ,
Since the electroforming mold requires an electrolytic cell having a size larger than that of the mold, there is a problem that the cost of a large-sized molded product becomes high. Therefore, it has hitherto been disclosed in JP-A-57-146613 and JP-A-56-56613. -56820 and JP-A-2-214618 disclose techniques for forming a metal spray on the mold surface.

[0004]

However, although the above-mentioned technique of forming a metal spray on the molding surface side of the mold can solve the above-mentioned problems, it partially forms voids such as pinholes on the molding surface. However, it has a problem that a molded product having good dimensional stability cannot be obtained because the mold is easy to form and the rigidity of the mold is low.

The problem to be solved by the present invention is that it is excellent in so-called surface accuracy without forming voids such as pinholes on the molding surface of the mold, and is excellent in dimensional stability because it is excellent in rigidity of the mold. The object is to provide a simple mold for plastic molding that can obtain various molded products.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the above problems can be solved by providing a low melting point metal layer as a backing layer of a mold, and completed the present invention. It was

That is, according to the present invention, in a molding die having a pair of a lower mold and an upper mold, a molding surface of the lower mold and / or the upper mold is a metal plate, and a low melting point metal is used as a backing layer of the metal plate. The present invention relates to a simple mold for plastic molding, which has a layer.

The simple mold for plastic molding of the present invention is
Although its use is not particularly limited, a thermosetting resin material, which is composed of a lower mold and an upper mold, and in which a reinforcing material is inserted and / or liquid in a molding space formed when both molds are closed Can be preferably applied for so-called resin transfer molding, in which the resin is injected and cured.

The simple mold for plastic molding of the present invention is
The molding surface of the molding die that is paired with the lower mold and the upper mold (hereinafter,
The "mold surface" is a metal plate and may have a low melting point metal layer as a backing layer of the metal plate, and may be used as it is, but a metal plate layer is further added to the low melting point metal layer. It may have a sandwich structure or a multilayer structure in which a metal powder-containing resin layer is further provided on the low melting point metal layer. Among these structures, a multilayer structure having a metal powder-containing resin layer on the low melting point metal layer is preferable because it is easy to manufacture, the weight of the mold can be reduced, and the rigidity of the mold is remarkably excellent.

The metal plate used in the present invention is usually a mild steel plate S.
JIS-G-31 such as S-32, mild steel plate SS-34, mild steel plate SS-41, mild steel plate SS-50, and mild steel plate SS-55.
Examples include mild steel plates such as rolled steel plates represented by 01, aluminum, stainless steel, nickel, copper, various alloys, etc. Among them, mild steel plates are preferable from the viewpoints of high rigidity, high surface hardness, and high thermal conductivity.

The above metal plate is processed into a shape of a molded product by a sheet metal working method or a press working method. Further, the surface of the metal plate may be patterned, such as engraved, and plated.

The thickness of the metal plate is not particularly limited,
0.2-10m from the point that the sheet metal workability is good, the rigidity is high, and the amount of deformation can be kept low by the pressure during molding.
It is preferably m, and more preferably 1 to 5 mm from the viewpoint that this effect becomes remarkable.

Next, the low melting point metal layer, which is an essential constituent feature of the present invention, can be formed as a backing layer on the back side of the metal plate forming the mold surface by a thermal spraying method or a melt pouring method. Incidentally, in order to improve the adhesiveness between the metal plate and the low melting point metal layer, the interface of the metal plate may be subjected to sandblasting, primer coating, or rib processing.

The thermal spraying method is a method in which a low melting metal is melted or sprayed in a semi-molten state on a metal plate to form a low melting point metal layer. Specifically, an arc spraying method, a plasma spraying method, a gas spraying method is used. Law etc. are mentioned.

The low melting point metal is not particularly limited as long as it has a lower melting point than the metal plate material forming the surface of the mold, but a melting point of 100 to 1000 ° C. further enhances the rigidity of the mold, and further It is preferable because the melt pouring operation is easy.

Specific examples of such a low-melting point metal include lead, aluminum, zinc, aluminum-zinc alloy, and bismuth-based alloy. Among them, zinc has a low melting point and adheres to a metal plate. It is preferable in terms of excellent properties.

The thickness of the metal layer having a low melting point is excellent in the rigidity of the mold, the dimensional stability of the molded product, and the heat storage due to thermal spraying when the backing layer is formed. It is preferably from 0.5 to 5 times, and more preferably from 1 to 4 times, from the viewpoint that this effect becomes remarkable.

In the present invention, as described above, it is preferable to further provide a metal powder-containing thermosetting resin on the low melting point metal layer, so that the mold rigidity can be further improved. Especially as a thermosetting resin having heat resistance, for example,
Epoxy resins, vinyl ester resins, unsaturated polyester resins, etc., which are generally good in heat resistance and have a small curing shrinkage, are preferable.

The metal powder is used for the purpose of increasing the thermal conductivity, and the average particle diameter of iron, copper, aluminum, etc. is 0.1 to 0.1.
2.0 mm is preferable. Further, if necessary, calcium carbonate, or an inorganic filler such as a glass hollow body may be added. The mixing ratio is 50 to 1000 parts by weight of metal powder and 50 to 500 parts by weight of inorganic filler with respect to 100 parts by weight of resin.
Used in the range of parts by weight.

In the present invention, it is preferable to provide a space in the backing layer in which the metal powder-containing thermosetting resin layer is further provided on the low melting point metal layer, from the viewpoint that water for heating or cooling the mold can be passed through. Specifically, copper pipes are previously soldered to the back surface of a metal plate serving as the mold surface at equal intervals of about 30 mm, and then a backing process is performed using a low melting point metal and a metal powder-containing thermosetting resin.

The simple mold for molding of the present invention is a component or device for smoothly performing molding as a mold, such as a guide pin, an ejector pin, an air vent, a molding material inlet, a mold clamping clamp, Also, a heat insulating material may be attached to the back surface of the mold for the purpose of keeping heat.

[0022]

EXAMPLES The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

Example 1 Sheet metal processed into a shape as shown in FIG. 1 and having a thickness of 3 m
m sheet metal mold (mild steel plate SS-32) was prepared. Next, the back side of the sheet metal mold is a steel grid FG made by Mutsua Steel Grains Co., Ltd.
Blast processing of -70 was performed using a BA-1 type blast machine manufactured by Atsuko Tekko Co., Ltd. After cleaning the blasted surface with dry air, use a copper pipe for temperature control with an inner diameter of 10 mm for 30 m
Soldered to the blast surface at m intervals.

Next, zinc was uniformly sprayed to a thickness of 3 mm by using an arc type metal sprayer EAS-400 manufactured by Thermal Spray Giken Co., Ltd. to form a first backing layer. After degreasing and drying the sprayed surface with toluene, Sanyo Kasei Co., Ltd. aluminum powder-containing epoxy resin Sun Module LB-50 / LH-50 (main agent /
(Curing agent) at 40 ° C for 2 hours and then at 150 ° C for 5 hours.
Post-cured for a period of time to provide a second backing layer 10 mm thick. Finally, urethane foam with a thickness of about 30 mm is used as a heat insulating material.
Sprayed.

In addition, parts or devices constituting male and female molds were produced as shown in FIG. 2 to obtain male and female simple molds for plastic molding. (Evaluation of mold surface accuracy) Hot water was passed through a temperature control copper pipe to keep the mold at 40 ° C., and a gel coat resin (“Polyton White GX-16 manufactured by Dainippon Ink and Chemicals, Inc.” was first applied to the lower mold.
738C ") was uniformly spray-coated in a thickness of 300 μm and cured for 20 minutes.

Next, preformed glass fibers were added on the gel-coated surface so that the glass content of the molded product was 30% by weight, and the upper mold and the lower mold were closed at a pressure of 10 kg / cm ² . Next, using a standard RTM injector (manufactured by Venus Gasmer), unsaturated polyester resin ("Polylite PC-670" manufactured by Dainippon Ink and Chemicals, Inc. was injected from the upper mold inlet and cured, and after 30 minutes, the mold was molded. It was opened and the molded product was taken out to obtain a molded product shown in FIG.

The surface accuracy of the mold was evaluated by measuring the surface smoothness of the molded product and observing the state of pinholes on the surface of the mold. The results are shown in Table 1. The evaluation method was a method in which the surface roughness of the molded product was measured by using a surface roughness measuring instrument “SURFCOM 550A” manufactured by Tokyo Seimitsu Co., Ltd., and the generation of pinholes on the mold surface was visually evaluated. is there.

(Evaluation of Rigidity of Mold) A mold manufactured as described above without using a temperature control pipe has a width of 30 and a length of 300.
(Mm) to cut into test pieces, JIS-K-70
According to 55, the flexural deformation amount of the test piece was measured. still,
This evaluation method is a measurement of the deflection variation when a load rate of 2.5 mm / min is applied from the mild steel plate surface and a load of 45 kg / cm ^{2 is} applied. The results are shown in Table 2.

Comparative Example 1 Thickness obtained by sheet metal working into a shape of a molded product as shown in FIG.
An 8 mm sheet metal mold (soft steel plate SS-32) was prepared. Next, the surface of the sheet metal mold is blasted in the same manner as in Example 1,
Next, zinc was sprayed uniformly in a thickness of 0.3 to 0.5 mm.

Next, the sprayed surface was polished and finished with sandpaper of grain size # 320 to # 2000 to obtain a zinc sprayed layer / sheet metal layer having a thickness of 3.2 mm and a zinc sprayed surface serving as a molding surface. Got the mold.

Using this mold, the surface condition was evaluated in the same manner as in Example 1 except that the temperature control copper pipe and urethane foam were not used, and the load was applied from the zinc sprayed surface to Example 1. In the same manner, evaluations of rigid products were performed. The evaluation results of surface accuracy are shown in Table 1 and the evaluation results of rigidity are shown in Table 2.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

EFFECTS OF THE INVENTION According to the present invention, the molding surface of the mold is free from voids such as pinholes, that is, so-called surface precision is excellent, and the rigidity of the mold is also excellent, so that the molding has good dimensional stability. It is possible to provide a simple mold for plastic molding from which a product is obtained.

The thus obtained simple mold for plastic molding is inexpensive, has a short production period, and has sufficient performance as a simple mold for resin transfer molding and artificial marble.

[Brief description of drawings]

[Figure 1]

FIG. 1 shows a perspective view of a molded product molded by a simple mold according to the present invention. FIG. 2 shows a male / female sectional view. 1: Mold surface (sheet-metal processed surface of metal plate) 2: Zinc metal sprayed layer 3: Aluminum powder-containing epoxy resin layer 4: Urethane foam layer 5: Reinforcing frame 6: Molding material injection hole 7: Guide pin 8: Guide pin insertion hole 9: Silicon rubber for soft pinch 10: Copper pipe for temperature control

Claims (9)

[Claims] 1. A molding die comprising a pair of a lower mold and an upper mold, wherein the surface of the lower mold and / or the upper mold is a metal plate, and a low melting point metal layer is provided as a backing layer of the metal plate. A simple mold for plastic molding. 2. The simple mold according to claim 1, wherein the plastic mold has a metal plate layer, a low melting point metal layer, and a metal powder-containing thermosetting resin laminated in that order from the molding surface side. 3. A simple mold for plastic molding is formed by laminating a metal plate layer, a low melting point metal layer, and a metal powder-containing thermosetting resin in this order from the molding surface side, and further, the low melting point metal layer and the metal powder. The simple mold according to claim 2, wherein the layer made of the thermosetting resin-containing resin has a space. 4. The simple mold according to claim 1, 2 or 3, wherein the metal plate has a thickness of 0.2 mm to 10 mm. 5. The simple mold according to claim 4, wherein the thickness of the low melting point metal layer is 0.5 to 5 times the thickness of the metal plate. 6. The simple mold according to claim 1, wherein the low melting point metal layer is formed by thermal spraying or pouring. 7. The low melting point metal layer has a melting point of 100 to 1
The simple mold according to any one of claims 1 to 6, which is made of a metal having a temperature of 000 ° C. 8. The simple mold according to claim 3, wherein the simple mold for molding plastic has an injection hole and a deaeration hole penetrating the mold cross section. 9. A simple mold for plastic molding comprises a lower mold and an upper mold, and a reinforcing material is inserted and / or liquid thermosetting in a molding space formed when both molds are closed. The simple mold according to claim 1, which is a mold for resin transfer molding in which a resin material is injected and cured.