JPH08300361A - Mold for molding resin - Google Patents

Abstract

PURPOSE: To provide a mold having sufficient corrosion resistance against a corrosive substance generated from a resin and preventing the peeling and destruction of layer by injecting fluorine ions into the cavity of a mold for molding a resin containing a specific metal to form a specific metal fluoride layer on the molding surface of the mold. CONSTITUTION: Fluorine ions are injected into the cavity 14 formed by molds 1, 2 for molding a resin containing either one of Ni, Fe, Cr and Zn to form layers 3 containing metal fluoride of either one of NiF2 , FeF2 , FeF3 , CrF3 and ZnF2 on the molding surfaces of the molds. Metal fluoride itself is chemically stable and the reactivity thereof against a corrosive substance becomes markedly low as compared with a metal into which no fluorine ions are injected. The layers 3 containing metal fluoride formed on the surfaces of the molds 1, 2 by injecting fluorine ions are obliquely distributed in the depth direction thereof and, therefore, no clear interface is formed. Therefore, the layers 3 are not peeled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molding die.

[0002]

2. Description of the Related Art A resin molding die has a problem that a molding surface is corroded by a gas generated from the resin at the time of molding depending on the kind of resin to be molded. Typical examples of the corrosive substances include chlorine-based polymerization catalysts added to polycarbonate, fluorine and hydrogen fluoride decomposed and produced by various fluorine-modified resins, and chlorine or hydrogen chloride decomposed and produced by vinyl chloride resin. .

Various measures have heretofore been taken to prevent the mold molding surface from being corroded by these corrosive gases. As a technique of this kind, for example, Japanese Patent Laid-Open No.
The invention disclosed in Japanese Patent Publication No. 3-27223 or Japanese Patent Publication No. 04-27013 is known. And, in the case of the mold described in the former publication, a film state having abrasion resistance and corrosion resistance is adhered and formed on the surface of the mold master by vapor phase growth. The point is how to attach and form it on the mold surface. Further, in the case of the mold described in the latter publication, it is a method of subjecting an aluminum-based mold surface to a composite anodizing treatment, and improving the hardness, strength, lubricity, non-adhesiveness and corrosion resistance of the mold surface. It is a thing.

[0004]

However, in the invention disclosed in the former publication, the film-like body is adhered and formed on the mold surface of the mold, but the film-like body is sufficiently adhered to the surface of the mold. Therefore, there is a problem that stress concentrates on the interface between the film body and the die master during heating and cooling of the mold or during mold release, and the film body peels or breaks.

In the invention disclosed in the latter publication,
Since the corrosion resistance of the composite anodic oxide coating formed on the surface of the aluminum-based mold is not sufficient for corrosive substances such as acids, the types of resins applicable to this mold are limited, and the anodic oxide coating for acids is Since the corrosion resistance tends to decrease as the amount of alloy components other than aluminum in the mold increases, there is a problem that it is difficult to use a high-strength aluminum alloy containing many additive components.

Therefore, the present invention has been made in view of the above-mentioned problems, and has sufficient corrosion resistance to a corrosive substance generated from a resin to be molded, and a corrosion resistance imparting portion at the time of heating / cooling or releasing. It is intended to provide a resin molding die that does not peel off.

[0007]

In order to achieve the above object, the resin molding die of the present invention has a resin molding containing any one of Ni, Fe, Cr and Zn as shown in the conceptual diagram of FIG. Fluorine ions are injected into the cavities 14 of the molding dies 1 and 2 and at least the molding surface of the mold is made of NiF ₂ ,
It is characterized by being formed by forming a layer 3 of any one of F ₂ , FeF ₃ , CrF ₃ , and ZnF ₂ .

The ion implantation in this case is performed by ionizing particles intended to be added to the surface of the mold, accelerating them from several KeV to several 100 KeV in an ultrahigh vacuum, and adding them to a solid substrate. This is a method of forming a layer having specific properties different from the mold material on the surface.

The material of the molds 1 and 2 used in the present invention is Fe, Ni-based magnetic metal, or Fe, Cr.
It is possible to use a SUS-based steel material whose main component is, or a non-ferrous metal such as a Zn alloy. Further, as the fluorine gas, F ₂ , HF and the like are used, of which F ₂ is particularly preferable.

[0010]

According to the present invention, fluorine ions are added to the molds 1 and 2
By the method of injecting into the cavity 14, the layer 3 containing the metal fluoride can be formed on the molding surface. Note that vapor deposition, sputtering, C as a method other than ion implantation
In thin film processing such as VD, a clear interface is formed between the metal fluoride layer adhered and formed on the molding surface and the metal base. If such an interface is present, the lattice constant is different in most cases. Insufficient adhesion is not obtained. Further, since the metal and its salt have different physical properties such as coefficient of thermal expansion, stress is likely to be concentrated at the interface due to stress such as temperature change and external force, so that the metal fluoride layer may be peeled or broken.

On the other hand, the layer containing the metal fluoride formed on the surface of the base material by implanting ions is distributed in a gradient in the depth direction, so that no clear interface is formed. Therefore, this layer has no risk of peeling. Regarding the corrosion resistance of this layer, polycarbonate, fluorine-modified resin, and vinyl chloride resin were used for injection molding, and as a result of a comparative test of the number of moldings until the occurrence of molding failure due to corrosion of the molding surface, the ion-implanted mold was It was confirmed that it was superior to the mold without ion implantation. That is, the metal fluoride itself is chemically stable, and its reactivity to corrosive substances and the like is much lower than that of a metal that has not been ion-implanted.

[0012]

Embodiment 1 An embodiment of the present invention will be specifically described below with reference to the drawings. FIG. 2 is a cross-sectional view of a mold having a corrosion resistant layer formed in Example 1. In this embodiment, in order to form a gear with a shaft (diameter 10 mm, thickness 1 mm), SU
The molds 4 and 5 shown in FIG. 2 are formed by using the S-based steel material PD555 (manufactured by Daido Steel Co., Ltd.), and the molding surfaces of the molds 4 and 5 are washed, and then ion-implanted by an ion implanter. Fluorine ions (F ⁺ ) with energy of 40 KeV were injected into the cavity 15 at an injection amount of 1 × 10 ¹⁸ ions / cm ² to form the corrosion resistant layer 6 on the molding surface.

Fluorine resin-added polycarbonate resin (Upilon LS2010 manufactured by Mitsubishi Gas Chemical Co., Inc.) was injection-molded into the mold having this structure by an injection molding machine (Nestal 50 manufactured by Sumitomo Heavy Industries, Ltd.), The number of times of molding until the occurrence of a defective molded product due to corrosion of the molding surface was evaluated in comparison with the case of using a mold of the same shape but not implanted with ions.

As a result, as shown in the column of Example 1 of Table 1, as a result of molding for about 50,000 shots, peeling, destruction and corrosion of the corrosion resistant layer 6 were not recognized, and the resin was seized on the mold. ,
Almost no defective shape of the molded product occurred. On the other hand, when a mold without ion implantation was used, a part of the molding surface was corroded after about 5,000 shots, and seizure of the resin on the mold and defective shape of the molded product frequently occurred. Further, when the molding surface after ion implantation was analyzed by XPS (X-ray photoelectron spectroscopy), bonding of Cr and F and Fe and F was recognized, and chromium fluoride and iron fluoride were found in the corrosion-resistant layer 6. It is considered to have been formed.

According to this embodiment, the mold into which the fluorine ions are implanted has excellent corrosion resistance, and the corrosion resistant layer is not peeled or broken. Therefore, the defective molding is eliminated, the inspection process can be simplified, and the maintenance of the molding die is not required, so that the productivity is significantly improved.

[0016]

[Embodiment 2] FIG. 3 is a sectional view of a mold having a corrosion resistant layer according to Embodiment 2. In this embodiment, in order to form a biconvex lens (curvature radius 150 mm, surface roughness Rmax 0.05 μm, diameter 10 mm, wall thickness 2 mm), SUS steel material PD555 (manufactured by Daido Steel Co., Ltd.) is used. Three
The molds 7 and 8 shown in FIG. 2 are formed, the molding surfaces of the molds 7 and 8 are subjected to electroless Ni plating 9 having a thickness of 2 μm, and the molding surfaces are washed, and then the ion energy
KeV fluoride ions (F ⁺ ) were injected into the cavity 16 at an injection amount of 1 × 10 ¹⁸ ions / cm ² to form the corrosion-resistant layer 10 on the molding surface.

Polycarbonate resin (Iupilon S3000 manufactured by Mitsubishi Gas Chemical Co., Inc.)
R) is an injection molding machine (Nestal 5 manufactured by Sumitomo Heavy Industries Ltd.)
In (0), injection molding was performed, and the number of times of molding until defectiveness of the molded product due to corrosion of the molding surface was evaluated as compared with the case of using a mold of the same shape but not ion-implanted.

As a result, as shown in the column of Example 2 in Table 1, as a result of molding for about 50,000 shots, peeling, destruction and corrosion of the corrosion resistant layer 10 were not recognized, and the resin was seized on the mold. ,
Almost no defective shape of the molded product occurred. On the other hand, in the case of using a mold not implanted with ions, corrosion was observed on a part of the molding surface after about 20,000 shots, and the resin was often seized on the mold and the shape of the molded product was often defective. Further, when the molding surface after ion implantation was analyzed by XPS (X-ray photoelectron spectroscopy), a bond between Ni and F was recognized, and it is considered that nickel fluoride was formed in the corrosion resistant layer 10.

According to this embodiment, the same effect as that of the first embodiment is obtained, and since the surface roughness of the die molding surface before and after the implantation of fluorine ions does not change, high surface accuracy is required. It can be carried out in some cases.

[0020]

[Embodiment 3] FIG. 4 is a cross-sectional view of a mold having a corrosion resistant layer according to Embodiment 3. In this example, in order to mold a donut-shaped disc (diameter 89 mm, surface roughness Rmax 0.05 μm, hole diameter 10 mm, wall thickness 1 mm), molds 11 and 12 were formed using zinc, and this mold was used. 11 and 1
After cleaning the molding surface of No. ² , fluorine ions (F ⁺ ) having an ion energy of 40 KeV were injected into the cavity 17 at an injection amount of 1 × 10 ¹⁸ ions / cm ² by an ion implantation device to obtain corrosion resistance on the molding surface. Layer 13 of was formed.

A vinyl chloride resin (Vinicron E manufactured by Mitsui Toatsu Chemicals, Inc.) was injection-molded with a mold of this construction using an injection molding machine (Nestal 50 manufactured by Sumitomo Heavy Industries, Ltd.) to form a molding surface. The number of times of molding up to the occurrence of a defective molded product due to corrosion was evaluated in comparison with the case of using a mold having the same shape but not injected with ions.

As a result, as shown in the column of Example 3 in Table 1, as a result of molding for about 10,000 shots, peeling, destruction and corrosion of the corrosion resistant layer 13 were not recognized, and the resin was seized on the mold. ,
Almost no defective shape of the molded product occurred. On the other hand, in the case of using a mold without ion implantation, corrosion was observed in a part of the molding surface after about 3,000 shots, and the resin was often seized on the mold and the shape of the molded product was defective. Further, when the molding surface after ion implantation was analyzed by XPS (X-ray photoelectron spectroscopy), a bond between Zn and F was recognized, and it is considered that zinc fluoride was formed in the corrosion resistant layer 13.

According to this embodiment, the same effect as that of the second embodiment can be obtained.

[0024]

[Table 1]

[0025]

According to the present invention, the corrosion resistance of the layer formed by implanting the fluorine ions is higher than that of the mold base, and the corrosion resistance of the corrosive substances generated from the resin is sufficient. Further, since this layer does not peel or break, the life of the mold is extended, and maintenance of the mold becomes unnecessary. As a result, the number of times of molding until a molding failure due to mold corrosion occurs can be significantly increased, the die cost per product can be reduced, and since the molding failure does not occur, the inspection process of the molded product can be simplified. As a result, productivity can be significantly improved.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a resin molding die of the present invention.

FIG. 2 is a cross-sectional view of a mold having a corrosion resistant layer according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view of a mold having a corrosion resistant layer according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view of a mold having a corrosion resistant layer according to a third embodiment of the present invention.

[Explanation of symbols]

 1,2,4,5,7,8,11,12 Resin molding die 3,6,10,13 Corrosion resistant layer 9 Ni plating layer 14,15,16,17 Cavity

Claims (1)

[Claims] 1. A fluorine ion is injected into a cavity of a resin molding die containing any one of Ni, Fe, Cr and Zn, and NiF ₂ , FeF ₂ ,
A resin molding die, comprising a layer of any one of FeF ₃ , CrF ₃ , and ZnF ₂ .