JPS641560B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a releasable coating formed on a mold used for molding plastic molded products, etc., and particularly for forming a mold etc. with excellent mold release properties. The present invention relates to a method for producing a suitable peelable coating.

Conventionally, molds for plastic molded products, etc. have had their surfaces (the surface facing the molded product forming space where the molded product will be molded, hereinafter referred to as the "cavity surface") for the purpose of improving wear resistance, peelability, etc. hard chromium plating film or electroless nickel plating film is being formed. However, when a plastic molded product or the like is actually molded using these molds, the molded product may adhere to the mold cavity surface during mold release, making it difficult to release the mold. For example, when molding an ethylene-vinyl acetate copolymer resin molded product using a mold with a hard chrome plating coating applied to the cavity surface, the resin often sticks and the mold cannot be removed cleanly. For this reason, protective measures have been taken to carefully and thoroughly apply mold release agent after each molding process, but this process of carefully applying mold release agent after each molding process is extremely troublesome, and the resin may If adhesive adheres to the mold cavity surface, the adhered resin must be removed and cleaned after each molding, which greatly impedes workability. In addition, the resin adheres to the mold, causing problems such as premature wear of the mold.

The present invention has been made to improve the above-mentioned situation, and is a plating coating in which particles of a fluororesin such as tetrafluoroethylene resin are eutectoid on the surface of an object on which a peelable coating is to be formed, such as the cavity surface of a mold. At the same time, after plating, fluororesin particles are newly supplied to the surface of the plating film, and then the fluororesin particles exposed on the surface and the fluororesin newly supplied to the surface are softened or melted and plated. By coating part or all of the surface of the coating with fluororesin, a fluororesin coating with excellent adhesion is formed and has excellent peeling and mold release properties, making it suitable for use in molds, for example. In some cases, molded products such as plastics can be reliably released from the mold without using a mold release agent, or even if a mold release agent is used, by simple application, it is possible to improve workability and improve workability. The present invention provides a method for producing a releasable coating, which allows the formation of a mold with very high durability and less wear and tear on the mold.

Hereinafter, the present invention will be described in detail with reference to the drawings, taking as an example the case where a releasable coating is formed on a mold.

The mold to which the present invention is applied includes vinyl acetate resin,
As a mold for molding plastic molded products such as polyester resin, polyurethane resin, polyvinyl chloride resin, polyethylene resin, polypropylene resin, rubber molded products, glass molded products, and other molded products, or as food molds and pharmaceutical molds. It is used as a mold, etc., and can be employed for any purpose such as injection molding, extrusion molding, blow molding, compression molding, or casting. As the mold material, an appropriate material such as steel or copper alloy can be selected according to the purpose, and the mold can be manufactured into a desired shape according to the shape of the molded product.

The present invention forms a tamping film by uniformly eutectoiding fluororesin particles on the surface (cavity surface) facing the molded product forming space on the mold body formed in the desired shape. Furthermore, a fluororesin coating layer is formed thereon. This is the first
To explain with reference to the figure and FIG. 2, 1 is the mold body, 2 is the cavity surface, and 3 is the cavity surface 2.
In the fluororesin particle eutectoid plating film formed on the surface, 4 is the metal matrix of the plating film 3, 5 is the fluorocarbon resin particle, and 6 is the metal matrix of the plating film 3, and 6 is the metal matrix of the plating film 3, and 6 is the metal matrix of the plating film 3, and the plating film has particles 5' exposed on the surface of the plating film 3. This is a fluororesin coating layer formed by heating and melting the newly supplied fluororesin. In addition, when the mold consists of two molds, for example, a male mold and a female mold, the above-mentioned fluororesin particle eutectoid plating film is formed on the cavity surface of either of them, and a fluororesin coating layer is further applied. It is preferable to form.

In the present invention, the fluororesin particles include tetrafluoroethylene resin, tetrafluoroethylene-hexafluoropropylene copolymer resin, trifluorochloroethylene resin, vinylidene fluoride resin, vinyl fluoride resin,
These can be used alone or in combination. In this case, the particle size is less than 150 μm, especially from 0.3 to
The thickness is preferably 20 μm. Further, if necessary, other inorganic or organic polymer fine particles can be eutectoid in addition to the fluororesin particles.

There are no particular restrictions on the matrix of the plating film, and appropriate metals such as copper, silver, zinc, and tin can be selected depending on the purpose of the mold, but nickel, nickel-cobalt alloy, and nickel- Nickel alloys such as phosphorus alloys and nickel-boron alloys are preferably used because they have excellent heat resistance, surface hardness, and the like.

The method for forming the fluororesin particle eutectoid plating film may be an electroplating method or an electroless plating method, and conventionally known plating methods can be adopted. Particles of fluororesin such as ethylene resin are treated in the presence of an activator such as a cationic activator, a nonionic activator, or an amphoteric activator, if necessary.
Alternatively, a method for plating may be adopted in which these activators are dispersed in a desired plating solution using a combination of cationic and nonionic activators, for example.

The amount of fluororesin particles suspended in the plating solution is preferably 250g/or less, particularly 30 to 100g/.In the present invention, the fluororesin particles in the plating film formed on the mold cavity surface The amount of eutectoid particles is not particularly limited, but it is 5 to 5 for the plating film.
It is preferable to adjust the amount to 30% by volume, especially 10 to 30% by volume.

Furthermore, by adding a brightening agent to the plating solution and making the matrix of the eutectoid plating film formed on the mold cavity surface a glossy precipitate, the mold releasability of the mold can be further improved. , and the mechanical strength of the matrix can be significantly increased. For example, in the case of nickel plating, by setting the Vickers hardness of the plating film to 400 or more,
Gives an excellent effect.

As mentioned above, the eutectoid plating film of fluororesin particles is formed by uniformly suspending the fluororesin particles in a desired plating solution and plating under normal plating conditions. After the formation of the deposited coating, a chromium-plated coating layer may be formed on this coating. For example, it is possible to form a chromium-plated coating on a glossy nickel-plated coating on which fluororesin particles are eutectoid. can. In this case, the chrome plating film is not formed on the fluororesin particles exposed on the surface of the bright nickel plating film, but is formed only on the bright nickel plating film matrix.
Further, as shown in FIG. 3, a desired base plating film 7 may be formed on the cavity surface 2 of the mold body 1, and then a fluororesin particle eutectoid plating film 4 may be formed.

In the present invention, fluororesin particles such as tetrafluoroethylene resin are eutectoided, and new fluororesin particles are supplied to the surface of the taming coating.
Next, the fluororesin particles exposed on the surface of the plating film and the fluororesin supplied on the plating film are heated and softened or melted to form the cavity surface 2 of the mold body 1, as shown in FIG. The fluororesin particles 5 formed on the surface of the coating 3 are softened or melted to form a fluororesin coating layer 6 on part or all of the surface of the coating 3. In this way, part or all of the surface of the plating film (the surface of the eutectoid plating film, or the surface of the final plating film if another final plating film is formed after the eutectoid plating film) is eutectoid plating. By covering the fluororesin particles exposed on the coating surface and the fluororesin separately supplied to the surface of the eutectoid plating coating with a fluororesin,
The release property of the mold can be made very good, and the adhesion to the surface of the plating film is improved by separately supplying fluororesin particles to the surface of the eutectoid plating film and softening and melting them at the same time. It is possible to form a thicker fluororesin coating with a high

To explain in more detail the effect of the mold obtained by adopting the present invention, a plating solution having the following composition was used on the cavity surface of an ethylene-vinyl acetate copolymer resin molding mold (made of steel) under the following conditions. By plating, a glossy nickel plating film in which tetrafluoroethylene resin particles are evenly eutectoid is created.
A thickness of 50 μm was formed.

Plating solution composition, plating conditions NiSO ₄・6H ₂ O 280g/ NiCl ₂・6H ₂ O 45 〃 H ₃ BO ₃ 40 〃 Primary brightener 2 〃 Secondary brightener 0.2 〃 Tetrafluoroethylene resin particles (particle size Average 0.3μm,
(manufactured by Daikin Industries, Ltd.) (solid content) 50 〃 PH 4.0 to 4.5 Plating temperature 55℃ Cathode current density 4A/dm ² anode Nickel stirring propeller Approximately 15% by volume is contained in the formed plating film
Particles of polytetrafluoroethylene (tetrafluoroethylene resin) were eutectoid, and the film had a Vickers hardness of 580.

Next, tetrafluoroethylene resin was further supplied onto the eutectoid plating film and placed in a heating furnace at 370°C for 20 minutes.
The tetrafluoroethylene resin particles exposed on the surface of the eutectoid plating film and the tetrafluoroethylene resin supplied to the surface were melted to completely coat the surface of the plating film with the tetrafluoroethylene resin.

Using the thus obtained mold (product of the present invention) and a mold with a hard chrome plating film formed on the cavity surface (conventional product), ethylene-vinyl acetate copolymer resin was actually molded. However, in the case of the product of the present invention, the ethylene-vinyl acetate copolymer resin molded product did not stick and could be easily released from the mold even after 10 consecutive moldings without using a mold release agent. In contrast,
In the case of a conventional molding machine in which a hard chromium plating film was formed on the cavity surface, when molded without using a mold release agent, the resin immediately adhered to the cavity surface and the mold could not be released cleanly.

As described above, the method for producing a releasable coating according to the present invention involves forming a tough coating by eutectoiding fluororesin particles on the surface of an object on which a releasable coating is to be formed, and at the same time forming a tough coating by eutectoiding fluororesin particles on the surface of an object on which a releasable coating is to be formed. By softening or melting the fluororesin particles exposed on the surface of the plating film and the fluororesin supplied to the surface of the plating film, part or all of the surface of the plating film is coated with fluororesin. It is characterized by forming layers.

Therefore, the removable film according to the present invention has extremely good releasability and mold release properties because the fluorocarbon resin coating layer is formed on the surface of the fluorocarbon resin coating by eutectoiding of fluorocarbon resin particles. It is. Therefore, when the present invention is applied to a mold to form plastic or the like, it is possible to sufficiently release the mold without using a mold release agent, or even when a mold release agent is used, just by simply applying a small amount. Therefore, it is possible to improve the workability in terms of the work of applying a mold release agent, the work of removing plastics etc. stuck to the mold cavity surface, etc.

In addition, the method of the present invention performs plating using a plating solution that suspends fluororesin particles on the cavity surface, and then simply supplies new fluororesin particles and heat-melts the fluororesin particles. Peelable coatings can be easily produced. Furthermore, in the resulting plating film, the fluororesin particles are firmly embedded in the matrix, and the metal matrix is tightly and firmly bonded to the cavity surface or the underlying plating film. Therefore, the adhesion to the material is good, and the inconvenience of the plating film peeling off due to repeated use can be prevented. In addition, the fluororesin particles are supported by the matrix metal, and since the fluororesin coating layer is integrated with the fluororesin particles (surface exposed particles) eutectoided on the surface side of the plating film, it has good adhesion. It has high mechanical strength, excellent abrasion resistance, very little wear of the peelable coating, and is extremely durable.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing another example of a mold manufactured by the method of the present invention, FIG. FIG. 3 is a schematic cross-sectional view showing another example of a manufactured mold. 1... Mold body, 2... Cavity surface, 3...
Plating film, 4... Matrix, 5... Fluorine resin particles, 6... Fluorine resin coating layer.

Claims (1)

[Claims] 1. After forming a tough coating by eutectoiding fluororesin particles on the surface of an object on which a peelable coating is to be formed,
Supplying fluororesin particles to the surface of this plating film,
Next, the fluororesin particles exposed on the surface of the plating coating and the fluororesin supplied to the surface of the plating coating were softened or melted to form a fluororesin coating layer on part or all of the surface of the plating coating. A method for producing a releasable film, characterized by: 2 The fluororesin is a tetrafluoroethylene resin, a tetrafluoroethylene-hexafluoropropylene copolymer resin, 3
Claim 1, which is an ethylene fluoride fluoride resin, a vinylidene fluoride resin, or a vinyl fluoride resin
The method described in section. 3. The method according to claim 1 or 2, wherein the matrix of the plating film on which the particles of the fluorine-containing compound are eutectoid is nickel or a nickel alloy. 4. The method according to any one of claims 1 to 3, wherein the object on which the releasable film is to be formed is a mold.