JPH1034663A - Insulated mold and resin molding method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the improvement of the durability of a mold whole the excellent characteristics as the insulated mold are held as they are by a method wherein a notch having the specified width is formed at the edge face part of the mold, onto the wall surface of the mold cavity of a metal base mold of which a heat insulating layer and a metal layer are laminated in the order named. SOLUTION: In an insulated mold, the mold surface ineluding the mold cavity of a metal base mold A is covered with the covering layer made of a heat resistant polymer heat insulating layer B and a metal layer C. At the same time, the insulated mold has a structure having a notch e2 with its width ranging from 2-200μm at the edge face part of the insulated mold. By providing this notch e2, the breakage of the covering layer is prevented from starting from the end part of the insulated mold, resulting in allowing to remarkably improve the durability of the insulated mold. By providing the heat insulating layer B, direct contact between the metal layer C and the base mold A is eliminated, resulting in allowing to fully keeping the heat insulating properties, which is the primary aim of the insulated mold.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-insulating mold having excellent durability and a resin molding method using the same. More specifically, the present invention relates to a heat-insulating mold having excellent moldability in various molding applications such as injection molding and blow molding of a synthetic resin, and having excellent durability against shear stress and cooling / heating cycle during molding, and a resin molding method using the same. Things.

[0002]

2. Description of the Related Art In recent years, in synthetic resin injection molded products and blow molded products, manufacturing costs have been reduced by omitting post-processing such as painting, and environmental destruction due to solvent evaporation during painting has been reduced. There is a strong demand for improving the surface condition and making it unpainted. There is a particularly strong demand for omitting post-processing of electrical resin, electronic equipment, synthetic resin housings of office equipment, and the like.

[0003] A thermoplastic resin is injected into a mold cavity and molded, and in order to improve the reproducibility of the mold surface condition and the surface condition such as the appearance of a molded product, it is necessary to increase the resin temperature or the mold temperature or to increase the injection pressure. In general, a countermeasure based on molding conditions, such as increasing the value, is selected. The same applies to the blow molding, and in order to improve the appearance of the molded product, it is usually selected to respond to molding conditions such as increasing the resin temperature or the mold temperature or increasing the blow gas pressure.

[0004] Among these factors, the mold temperature has a particularly great influence on the mold temperature. The performance such as appearance can be improved by increasing the mold temperature. However, when the mold temperature is increased, the time required for cooling and solidifying the plasticized resin becomes longer, and the molding efficiency generally decreases. Therefore, there is a strong demand for a method of improving the reproducibility of the mold surface without increasing the mold temperature, or a method of not prolonging the cooling time even if the mold temperature is increased.

[0005] For example, a method of repeating heating and cooling of a mold by alternately flowing a heat medium and a cooling medium and attaching the holes for heating and cooling to the mold, respectively, is known as Plastic Tech.
nology, June, P .; 151 (1988) and the like, this method consumes a large amount of heat energy and the molding efficiency is not sufficiently improved. A mold in which a mold surface forming a mold cavity is covered with a heat insulating layer made of a substance having a low thermal conductivity, that is, WO.93 / 0
6980 and the like. When the moldability is improved by using a heat insulating layer made of a polymer on the outermost surface of the mold, the moldability can be improved, but the heat insulating layer is easily damaged during use. Further, depending on the type of the synthetic resin to be molded, there is a problem that it is difficult to release from a mold at the time of molding.

As a further improvement, a mold in which the surface of the heat insulating layer is further covered with a thin metal layer is known. For example, JP-A-53-86754 discloses a heat-insulating mold in which a metal mold surface is coated with a heat-insulating layer, and the heat-insulating layer surface is further coated with a thin metal layer. Thereby, the scratch resistance of the surface of the heat insulating layer and the releasability at the time of molding can be improved.

[0007]

In a heat-insulating mold in which the surface of a heat-insulating layer is further covered with a thin metal layer, it is difficult to make a sufficiently strong adhesion between each coating layer, that is, the metal layer, the heat-insulating layer, and the base mold. Yes, solving the problem of peeling of the coating layer is a major issue. In particular, the coating layer is likely to start to be damaged from peeling or deformation from the end of the mold. Nevertheless, there has not been any disclosure regarding the end face structure of the mold, particularly the improvement in moldability and durability of the mold by improving the end face structure.

An object of the present invention is to provide a heat-insulating mold in which a heat-insulating layer made of a heat-resistant polymer and a metal layer are sequentially laminated on the mold cavity wall surface of a metal base mold, that is, the properties as a heat-insulating mold, Insulation mold with excellent moldability in each molding application such as injection molding and blow molding, and without exfoliation or deformation of the coating layer due to cooling and heating cycles or shear stress during molding, and a resin molding method using the same. Is to provide.

[0009]

Means for Solving the Problems The present inventors have provided a notch structure at the end face of a mold in which a heat insulating layer and a metal layer are sequentially laminated on the mold cavity wall surface of a metal mold. By preventing the coating layer consisting of the heat insulating layer and the metal layer from coming into direct contact with other molds, and by optimizing the surrounding structure, the mold is maintained while maintaining the excellent features of the heat insulating mold. The inventors have found that the durability can be significantly improved, and have completed the present invention.

That is, the present invention is as follows. (1) A heat-insulating mold in which a heat-insulating layer made of a heat-resistant polymer and a metal layer are sequentially laminated on a mold surface constituting a mold cavity of a metal base mold, and a width 2 is provided at an end face of the heat-insulating mold. A heat-insulating mold having a notch in the range of ２００200 μm. (2) The heat-insulating mold according to the above item 1, wherein the heat-insulating mold is a split mold having a split surface on a mold cavity surface. (3) The heat-insulating mold according to the above 1 or 2, wherein the base mold has a bank structure. (4) The heat-insulating mold according to the above 1, 2 or 3, wherein the thickness of the heat-insulating layer is in the range of 0.05 to 3 mm, the thickness of the metal layer is in the range of 1 to 300 μm, and is 1/3 or less of the thickness of the heat-insulating layer. . (5) The width of the bank structure of the base mold is in the range of 0.1 to 10 mm, and the height thereof is 20/100 to 99/1 of the thickness of the heat insulating layer.
The heat-insulating mold according to the above item 3 or 4, which is in the range of 00. (6) The notch on the end surface of the heat-insulating mold has a width of 5 to 100.
μm and depth equal to or greater than the thickness of the metal layer, 3
The heat insulating mold according to the above 1, 2, 3, 4 or 5, which is / 4 or less. (7) the softening temperature of the heat-resistant polymer is higher than the molding temperature;
And 1, 2, 3, 4, 5 or 6 above. (8) The above-mentioned 1, 2, 3, 4, wherein the metal layer is a metal layer formed by chemical plating and / or electroplating.
5, 6 or 7 insulation molds. (9) The heat insulating mold according to the above item 8, wherein the metal layer is formed by sequentially laminating chemical nickel plating, chemical and / or electric copper plating, and chemical and / or electric nickel plating. (10) The heat-insulating mold according to the above 1, 2, 3, 4, 5, 6, 7, 8, or 9, wherein the heat-resistant polymer constituting the heat-insulating layer is polyimide. (11) A resin molding method using the heat-insulating mold of the above 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10. (12) The resin molding method according to the above (11), which is for molding a housing of a household appliance or an office machine.

In the present invention, the end face of the heat insulating mold is
This means a heat-insulating mold mating surface that constitutes a mold cavity mating portion between heat-insulating molds or a mold cavity mating portion of a heat-insulating mold and a mold made of metal only. That is, it refers not to the mold cavity surface but to its side surface. Further, the bank structure is a bank-shaped convex structure of the base mold provided in contact with the end face portion on the mold cavity surface of the base mold.

In the heat insulating mold of the present invention, a heat insulating layer made of a polymer having a remarkably low elastic modulus and a significantly different coefficient of thermal expansion than a metal is sandwiched between the base mold and the metal layer. The adhesion strength between the layers is not so large. Therefore, due to the thermal cycle and shear stress during molding,
The coating layer is susceptible to breakage such as peeling or deformation. The inventor has found that these breaks especially begin at the ends of the base mold and often spread and cause catastrophic breaks in the mold.

The heat-insulating mold of the present invention has a mold surface constituting a mold cavity of a base mold covered with a coating layer composed of a heat-insulating layer and a metal layer, and has a cutout structure at an end face of the heat-insulating mold. doing. By providing the cutout structure at the end face of the heat insulating mold, the damage of the coating layer is prevented from starting from the end of the heat insulating mold, and the durability of the heat insulating mold can be remarkably improved. Moreover, by eliminating direct contact between the metal layer and the base mold,
The heat insulating property which is the original purpose of the heat insulating mold can be sufficiently maintained. Furthermore, it has been found that by optimizing the peripheral structure as the heat-insulating mold, the durability of the heat-insulating mold can be remarkably improved while maintaining the excellent features as the heat-insulating mold.

Hereinafter, the present invention will be described in detail. A description will be given using a partial cross-sectional view of a specific example of the heat insulating mold structure of the present invention. FIG. 1 is a partial cross-sectional view of the heat-insulating mold of the present invention having a cutout structure at the end face, and FIG. 2 is a partial cross-sectional view of the heat-insulating mold having a bank structure on the surface of the base mold. FIG. 3 shows a comparative example of a heat-insulating mold having no cutout structure at the end face of the heat-insulating mold, and FIG. 4 shows a partial cross-sectional view of the heat-insulating mold in which the bank structure of the base mold is directly covered with a metal layer.

FIG. 1 shows a heat-insulating layer B made of a heat-resistant polymer on the surface of a mold constituting a mold cavity of a metal base mold A.
Exists, and the metal layer C exists thereon. Here, d2 is the thickness of the heat insulating layer, s2 is the thickness of the metal layer, e2 is the cutout width of the end face, and f2 is the depth. This corresponds to d0 in FIG. 2, that is, the case where the height of the bank is 0. FIG.
Has a bank structure A ′ in contact with the end face of the base mold of FIG. Here, d1 is the thickness of the heat insulating layer, s1 is the thickness of the metal layer, d0 is the height of the embankment, w1 is the width of the top of the embankment, b1 is the thickness of the heat insulating layer covering the embankment, and e1 is the cut of the end face. The notch width, and f1 is its depth.

FIG. 3 shows a conventional heat-insulating mold as a comparative example. The heat insulating layer B and the metal layer C are simply placed on the surface of the mold forming the mold cavity of the base mold A. Here, d3 is the thickness of the heat insulating layer, and s3 is the thickness of the metal layer. FIG. 4 also shows a heat insulating mold described in the comparative example. A heat-insulating layer B made of a heat-resistant polymer is present on the surface of a mold constituting a mold cavity of a metal base A, and a metal layer C is formed thereon.
Exists. The base mold has a bank structure A ′ and is directly covered with a metal layer C. Here, d4 is the thickness of the heat insulating layer, s4 is the thickness of the metal layer, and w4 is the top width of the bank.

The material of the base mold constituting the heat insulating mold of the present invention is iron or a steel material containing iron as a main component, aluminum or an alloy containing aluminum as a main component, a zinc alloy such as ZAS, a beryllium-copper alloy, or the like. Generally, it is selected from a wide range including a metal mold used for molding a synthetic resin. In particular, a die made of a steel material is inexpensive and can be used favorably. It is preferable that the surface of the metal mold in contact with the heat insulating layer of the metal mold is plated with hard chromium, nickel, or the like. The shape of the base mold differs depending on the shape of the target synthetic resin molded body.

The base structure of the base mold can be formed by a usual metal working method when the base mold is prepared. For example, a cutting method using a milling machine or a processing method such as finishing after embankment welding can be used. The heat-insulating layer constituting the heat-insulating mold of the present invention is made of a heat-resistant polymer. The heat-resistant polymer is selected from a thermoplastic polymer having a softening temperature higher than the molding temperature of the synthetic resin to be molded, and a heat-resistant curable resin having a heat resistance higher than the molding temperature. Preferably, the softening temperature is higher than the molding temperature of the synthetic resin to be molded, and the glass transition temperature is 140 ° C or higher, more preferably 160 ° C or higher, particularly preferably 190 ° C or higher, and / or the melting point is 200 ° C or higher, more preferably. Is a polymer having a temperature of 250 ° C. or higher.

The softening temperature of the synthetic resin is a temperature at which the synthetic resin can be easily deformed. Vicat softening temperature (ASTM D1525) for non-crystalline resin, heat deformation temperature (ASTM D648 18.6 kg / c load) for hard crystalline resin
m ² ), and the heat distortion temperature (ASTM D
648 with a load of 4.6 kg / cm ² ). Non-crystalline resin, for example, polystyrene,
Rubber-reinforced polystyrene, AS resin, ABS resin, polycarbonate, methacrylic resin, vinyl chloride resin, polyphenylene ether and the like. Hard crystalline resins include, for example, polyoxymethylene, nylon 6, nylon 66 and the like, and soft crystalline resins. For example, various polyethylene,
For example, polypropylene. The molding temperature is the temperature of the resin injected into the cavity.

The toughness of the heat-resistant polymer used in the heat-insulating layer is preferably 4% or more, more preferably 5% or more, and even more preferably 10% or more. The elongation at break is measured according to ASTM D638, and the tensile speed at the time of measurement is 5 mm / min. The heat-resistant polymer that can be used as the heat-insulating layer of the present invention can be widely selected from the heat-resistant polymers having the above-mentioned softening temperatures, and a particularly preferred heat-resistant polymer is a heat-resistant polymer having an aromatic ring in the main chain. is there.
Various aromatic non-crystalline or crystalline heat-resistant polymers, for example, polyimide, aromatic heterocyclic polymer, epoxy resin, polysulfone, polyethersulfone and the like can be used favorably.

As the polyimide, various linear non-thermoplastic polyimide resins, linear thermoplastic polyimide resins, and thermosetting polyimide resins can be widely used. Examples of the linear non-thermoplastic polyimide resin include, for example, polypyromellitic imide-based, polyphenyltetracarboxylic imide-based, polybenzophenone tetracarboxylic imide-based, polyamideimide, and polyetherimide. Examples of the resin include polybenzophenonetetracarboxylic acid imide-based and polybiphenyltelloracarboxylic acid imide-based resins, and examples of the thermosetting polyimide resin include a bismaleimide-based resin, a nadic modified polyimide, and a Diels-Alder-type polyimide.

In general, a high-molecular-weight linear polyimide has a large elongation at break and is tough and excellent in durability, and a polyimide containing fluorine has a high moisture resistance (the moisture resistance of the heat insulating layer is improved and the amount of water remaining in the resin is low). And the peeling of the heat insulating layer and the metal layer due to the foaming of water is suppressed.) And can be preferably used in some cases. Examples of the aromatic heterocyclic polymer include polybenzoazoles (eg, polybenzimidazole, polybenzoxazole, polybenzothiazole, polyetherbenzoxazole), polyhydantoins (eg, polyimidazolidin-2,4-dione) and polyparabanic acids ( For example, polyimidazolidin-2,4,5
-Trion) and the like.

These heat-resistant polymers can have a reduced thermal expansion coefficient by blending various fillers and fillers such as carbon fibers in order to improve the resistance to cooling and heating cycles during molding. The heat-resistant polymer having a reduced coefficient of thermal expansion can be preferably used as a heat insulating layer. Further, an epoxy resin having a small coefficient of thermal expansion or an epoxy resin containing various fillers in an appropriate amount can also be preferably used.
Generally, epoxy resin has a large coefficient of thermal expansion, and therefore has a large difference in coefficient of thermal expansion from a metal mold, and is susceptible to deterioration due to a thermal cycle. However, the coefficient of thermal expansion is small, for example, glass, silica, talc, clay, zirconium silicate, lithium silicate, calcium carbonate, alumina, powder and particles such as mica, glass fiber, whisker, blending an appropriate amount of carbon fiber, A filler-containing epoxy resin having a small difference in thermal expansion coefficient from that of a metal mold can be favorably used as the heat insulating layer of the present invention. In addition, a compounded epoxy resin obtained by adding a tough thermoplastic resin such as nylon, or various compounds that impart toughness such as rubber to an epoxy resin or a compounded epoxy resin with a filler can also be used favorably. Furthermore, a polymer alloy cured by mixing a polyimide or the like with an epoxy resin has excellent toughness and can be used favorably.

The thermal conductivity of these heat-resistant polymers is generally 0.0001 to 0.002 cal / cm · sec · ° C.
And, it is much smaller than metal and works effectively as a heat insulating layer.
However, mixing a large amount of an inorganic filler or a filler having high thermal conductivity may not be preferable because it increases the thermal conductivity and heat capacity of the heat insulating layer. When a composition in which an inorganic filler is mixed as a filler is used, the thermal conductivity is preferably 0.01 cal / cm · sec · ° C. or less, more preferably 0.005 cal / cm · sec · ° C. or less, and particularly preferably 0 cal / cm · sec · ° C. or less. 0.002 cal / cm · sec · ° C. or less.

In order to coat the base mold surface with a heat-resistant polymer and to firmly adhere the same, a sheet of a heat-resistant polymer is adhered or a powder of the heat-resistant polymer is sprayed and melt-bonded. However, a vapor deposition polymerization method, a coating method or a spray method on a metal surface can be preferably used. The vapor deposition polymerization method is basically a method in which a monomer (an acid dianhydride, a diamine, or the like) is evaporated to vapor-deposit and polymerize on a metal surface, and is an excellent method in that it can cope with adhesion and a complicated shape. For example, "Polyimide resin" Technical Information Association (1991) p. 29
9 gives a detailed description of this method.

The coating method or the spraying method is a method in which a heat-resistant polymer solution, a heat-resistant polymer precursor solution or a liquid precursor is applied or sprayed, and then heated and dried or cured to form a heat-insulating layer of the heat-resistant polymer. And practically particularly preferable. In this method, the heat-resistant polymer or the precursor of the heat-resistant polymer to be used is preferably soluble in a solvent or in a liquid state. For example, apply a solution of polyamic acid which is a precursor of polyimide,
Subsequently, a method of drying and heating and curing to form a polyimide layer on the mold surface can be favorably used.

In the heat-insulating mold of the present invention, the adhesion between the heat-insulating layer and the base mold and the adhesion between the heat-insulating layer and the metal layer must be sufficiently large. Specifically, it is preferable that peeling does not occur due to shear stress caused by molding of the synthetic resin more than 10,000 times or a cooling and heating cycle. In order to achieve this, the adhesion between the heat insulating layer and the metal mold and the adhesion between the heat insulating layer and the metal layer are preferably 0.5 kg / 10 mm or more at room temperature, more preferably 0.8 kg / 10 m.
m width or more, most preferably 1 kg / 10 mm width or more. The adhesion described in the present invention is the minimum value of the adhesion of the main part of the mold.

In order to improve the adhesion between the base mold and the heat insulating layer, general metals such as forming fine irregularities on the surface of the base mold, performing various plating, and performing primer treatment, etc.
Methods known in the art of polymer bonding can be used. CO group,
Polyimides containing a large amount of SO ₂ groups, such as polybenzophenonetetracarboxylic imide, polyamide imide, and polyimide sulfone, are particularly easily adhered to metal surfaces. However, although these polyimide resins are excellent in adhesiveness but slightly inferior in heat resistance, a method in which this thin layer is used as a primer layer and a high heat-resistant polyimide is coated thereon can be particularly preferably used. Also in this case, it is preferable to apply a high heat-resistant polyimide without completing the imidization of the primer layer in order to increase the adhesion.

The thickness of the heat insulating layer of the heat insulating mold of the present invention is generally selected in the range of 0.05 to 3 mm. Preferably, it is appropriately selected within a very narrow range of 0.1 to 0.8 mm. The preferred thickness depends on the molding method, and is preferably 0.1 to 0.5 mm, more preferably 0.12 to 0.3 mm in injection molding. In blow molding, it is preferably 0.3 to 0.8 mm, and more preferably 0.35 to 0.7 mm. With a thin heat-insulating layer having a thickness of less than 0.05 mm, the effect of improving moldability such as reproducibility of the mold surface of the molded article is small. If the thickness of the heat insulating layer exceeds 3 mm, the cooling time during molding becomes longer, and the molding efficiency decreases.

The greatest advantage of injection molding is that a mold having a complicated shape can be obtained by one molding, and the mold cavity generally has a complicated shape. It is difficult to smoothly cover the surface of the mold cavity having such a complicated shape with a heat insulating layer or the like. For this reason, it is a good method to polish the surface of the coated heat insulating layer later, or to grind the surface with a numerically controlled machine tool such as a numerically controlled milling machine and then finish the surface with smoothness.

The metal layer constituting the heat-insulating mold of the present invention is formed by coating and laminating a heat-insulating layer made of a heat-resistant polymer on the surface of the base mold. The method of coating the metal layer in the present invention generally includes a method of attaching a metal and a method of plating and laminating a heat insulating layer laminated on a base mold. As a bonding method, a method of laminating by bonding a metal film to a metal mold on which a heat insulating layer is laminated, or a method in which all or a partial layer of a heat insulating layer is preliminarily laminated on a metal film,
For example, a method of adhering to a base mold may be used. The metal film mentioned here is not necessarily limited to a flat film. For example, a case where a metal film in which a shape of a target formed body is given a shape in advance is bonded to a base mold having an opposite shape is also included.

When the heat-resistant polymer of the heat-insulating layer is a thermoplastic polymer, the metal film is bonded by heating and melting.
In the case of a curable polymer, a method of bonding and curing, or a method of bonding using an adhesive can be used. Whichever bonding method is used, it is natural that its heat resistance must be able to withstand the molding temperature. On the other hand, the plating lamination method can be particularly preferably used in that the metal layer can be firmly adhered to the heat insulating layer and that it can easily cope with a complicated mold shape. A preferred embodiment of the method for laminating metal layers of the heat insulating mold of the present invention will be specifically described by taking a plating lamination method as an example.

In producing the heat insulating mold of the present invention by the plating lamination method, a known resin plating technique can be used. For example, an etching aid is dispersed in at least the upper layer of the heat insulating layer, and after etching, plating is performed, so that a closely adhered metal layer can be formed. The etching aid may be dispersed throughout the heat-insulating layer, or may be dispersed only in the upper layer (metal layer side) of the heat-insulating layer. When the etching aid is dispersed only in the upper layer of the heat insulating layer, the heat-resistant polymer used for the heat insulating layer containing no etching aid (hereinafter referred to as the base heat insulating layer) and the heat insulating polymer containing the etching aid are used. The heat-resistant polymer may be the same or different.

When an etching aid is dispersed in the upper layer or the whole of the heat insulating layer in advance, and this is etched, a deep etching scratch like a hole, a groove or a crack originating from this is formed on the surface of the heat insulating layer. Can be. And
By chemically plating this, a metal layer firmly bonded to the heat insulating layer can be obtained. Therefore, on the metal layer side of the heat insulating layer, a heat-resistant polymer is used as a matrix (continuous phase), and a polymer and metal composite layer in which metal extending from the metal layer is fitted along holes, grooves or cracks is formed. Has become.
It is important to form this composite layer with a sufficient thickness, preferably a thickness of 0.1 μm or more, for laminating a durable metal layer.

In order to laminate the heat-insulating layer containing the etching aid on the heat-insulating layer, the heat-resistant polymer solution containing the etching aid dispersed in the heat-insulating layer, the precursor solution of the heat-resistant polymer or A method of applying or spraying a liquid precursor can be used. As a preferred embodiment, a method of laminating a heat insulating layer will be described in detail, taking as an example a case where the heat-resistant polymer is polyimide and the etching aid is an inorganic filler.

A solution of a polyamic acid, which is a polyimide precursor, is applied to the cavity of the base mold and the end face of the base mold, and is heated and dried in a state of not being completely imidized, and is repeatedly laminated to a predetermined thickness. Next, the same polyimide precursor solution containing the inorganic filler dispersed therein is applied repeatedly. Thereafter, heating is performed to complete the imidization, thereby forming an etching aid dispersion layer. Further, in each step, the surface is polished if necessary, and flattening is performed. Thus, a structure in which the inorganic filler is dispersed in the upper layer of the heat insulating layer made of polyimide can be achieved.

After laminating the heat insulating layer, dimensions and smoothing are performed by a processing method such as grinding or polishing, if necessary. When such post-processing is performed, it is preferable to anneal the surface of the heat insulating layer by heating. Etching the surface with a strong acid, strong alkali solution, strong oxidizing agent solution, strong reducing agent solution or a combination thereof while decomposing the surface layer,
The surface of the polyimide layer is made deep and uneven. Then neutralization,
By performing chemical plating through sensitization processing and activation processing, a composite layer in which a metal (anchor) extending from the metal layer is fitted into the heat insulating layer is created. Thereafter, a heat treatment is performed, and the metal layer is further electrolytically plated to form a metal layer firmly bonded to the heat insulating layer.

As the strong acid used for the etching, for example, hydrochloric acid, sulfuric acid, nitric acid water or an alcohol mixture and the like can be mentioned. As the strong alkali, for example, sodium hydroxide,
A water or alcohol solution such as potassium hydroxide or barium hydroxide may be used. Examples of the strong oxidizing agent include permanganate and chromate, and examples of the strong reducing agent include hydrazine. During the etching reaction, it is preferable to previously swell the surface of the heat-resistant polymer with a solvent having a high affinity for the heat-resistant polymer and a solvent having an affinity for the etchant solution in order to promote the etching reaction. There is.

Specific types of the etching aid and the etching method will be described below. A method in which an inorganic filler, an organic filler, or an incompatible organic compound is dispersed as uniformly as possible as an etching aid in all or the upper layer of the heat insulating layer made of a heat-resistant polymer, and the etching aid is dissolved or decomposed and removed. . In this method, the etching aid must be dissolved or decomposed in the etching solution. An inorganic filler or an organic filler is dispersed as uniformly as possible as an etching aid in all or the upper layer of the heat insulating layer made of a heat-resistant polymer, and an etching solution is permeated into an interface with the etching aid to form a matrix phase. How to partially erode. In this method, the etching aid does not necessarily need to be dissolved or decomposed in the etching solution. A method in which a polymer which is easily decomposed or extracted with an etchant is mixed, grafted or block-copolymerized, and then etched.

Examples of the inorganic filler include calcium carbonate, silicon oxide, calcium silicate, talc, attapulgite, asbestos, magnesium oxide, magnesium hydroxide, basic magnesium carbonate, hydrotalcite, alumina, aluminum hydroxide, aluminum oxide, Bentonite, zeolite, kaolin clay, pyrophyllite, sericite, mica, calcium sulfate,
Calcium sulfite, titanium oxide (rutile, anatase), potassium titanate, barium carbonate, barium sulfate, barium titanate, zinc oxide, zircon oxide, zircon silicate, iron oxide, molybdenum disulfide, antimony trioxide, silicon nitride, carbonized Inorganic fine powders such as silicon, carbon black, graphite powder, and carbon fiber can be used. Preferred inorganic fillers are calcium carbonate, silicon oxide, barium sulfate, zircon oxide, aluminum oxide and titanium oxide, particularly preferably titanium oxide, zircon oxide and aluminum oxide. Examples of the organic filler include polymer powders having a high softening temperature, such as matrix-incompatible powdery polyimide and powdery polyphenylene ether.

Since the particle size of these inorganic and organic fillers affects the pore size of the etching, and hence the size of the metal-inserted structure of the composite layer, the average particle size is preferably 0.005 to 5 μm, more preferably 0.01 to 0.01 μm. ~ 0.
5 μm, particularly preferably in the range of 0.01 to 0.1 μm. If the particle size is large, it is difficult to sufficiently exhibit the resistance to peeling of the obtained metal plating layer.

The incompatible organic compound is an organic compound incompatible with the heat-resistant polymer of the matrix, and is generally a crystalline organic compound. Dispersion of the etching aid such as the incompatible organic compound and the polymer which is easily etched into the heat-resistant polymer is usually performed by applying a uniform solution of the heat-resistant polymer to the base heat-insulating layer and drying the solvent to assist the etching. This can be achieved by insolubilizing and precipitating the agent.

Examples of the incompatible organic compound include various crystalline organic acid compounds and their inorganic salts, amide compounds and ester compounds. Specific examples include calcium salts of aliphatic carboxylic acids and aromatic carboxylic acids such as stearic acid and behenic acid, polyamide compounds, polyester compounds and the like. The polymer that is easily etched is related to the composition of the etchant, the heat-resistant polymer of the heat insulating layer and the matrix polymer of the composite layer, and is relatively easily etched, that is, eluted or decomposed than these matrix polymers. You can choose widely from easy polymers. For example, when polyimide is used for the heat-insulating layer including the composite layer, other polyimides, polyamides, polyesters, various conjugated diene polymers, vinyl polymers, and the like, which are more easily etched, can be used.

The amount of the etching aid used for dispersing the heat-resistant polymer in the heat-insulating layer is generally 0.1 volume of the volume of the etching aid-containing heat-insulating layer (or the whole heat-insulating layer when the entire heat-insulating layer contains the etching aid). 1 to 50% by volume, preferably 1 to 30% by volume, more preferably 3 to 15% by volume
It is. If the amount of the etching aid is too small or too large, it is difficult to achieve metal plating having high resistance to peeling of the metal layer.

The metal layer constituting the heat insulating mold of the present invention is formed by sequentially plating several metal layers on the heat insulating layer. The plating methods described here are chemical plating (electroless plating) and electrolytic plating. For example, it can be obtained by continuous chemical plating and / or electrolytic plating. The metal used is a metal used for general metal plating, and is, for example, one or more of chromium, nickel, copper, and the like. For example, chemical nickel plating, electrolytic nickel plating, chemical copper plating, electrolytic copper plating, electrolytic chromium plating and the like can be used favorably.

Next, a method for forming a metal layer will be specifically described with reference to an example of a metal plating method after etching.
Generally, plating is performed through some of the following steps.
First, chemical plating is performed after the etching aid-containing heat insulating layer is etched. The plating step is, for example, pretreatment → chemical corrosion (chemical etching with an acid or alkali) → neutralization → sensitization treatment (a metal salt having a reducing power is adsorbed and activated on the surface of the synthetic resin) → activation treatment (A noble metal such as palladium having a catalytic action is applied to the resin surface.) → Chemical plating (chemical nickel plating, chemical copper plating, etc.) → heat drying → electrolytic plating (electrolytic nickel plating, electrolytic copper plating, electrolytic chrome plating, etc.) Are generally performed in this order.

In particular, since heating and drying after this type of chemical plating may bring a remarkable effect on the improvement of peel strength, it is preferable to take sufficient temperature and time. Various plating layers can be further provided on the chemical plating (for example, chemical nickel plating). Preferred examples thereof are shown below. Preferably, at least one layer selected from these platings is coated. Chemical Nickel Plating Electrolytic Nickel Plating Chemical Copper Plating Electrolytic Copper Plating Electrolytic Chromium Plating In a particularly preferred embodiment of the metal layer structure, chemical nickel, chemical and / or electrolytic copper plating, and chemical and / or electric nickel plating are sequentially laminated on the heat insulating layer. The structure is Further, if necessary, it is preferable to overlay another plating having a different performance such as chromium plating on this.

In the heat-insulating mold of the present invention, the surface of the metal layer may be any one of mirror-like, matte, and grain-like, and is selected according to the purpose. The grain shape that can be used favorably is, for example, a grain pattern such as a leather grain shape, a grain grain shape, or a hairline shape. This graining method can be performed by various methods. The etching method can be used favorably, and the etching method using an acid can be best used. If the outermost surface layer of the heat-insulating mold is a metal that can be etched with an acid solution such as electrolytic nickel plating, electrolytic copper plating, or chemical nickel plating with low phosphorus content, the etching method used for general metal mold graining is used. Graining can be performed in the same manner as described above. That is, a method in which the surface of the metal layer is masked into a grain shape using an ultraviolet curable resin and then grained by acid etching can be used favorably.

The thickness of the metal layer is preferably 1 to 300 μm and not more than １ ／ of the thickness of the heat insulating layer. The more preferable thickness differs depending on whether the mold surface is mirror-like, matte, or grain-like. Further, the molding method used differs depending on any one of injection molding, blow molding and the like. The relationship between the more preferable thickness of the heat insulating layer and the more preferable thickness of the metal layer in a typical molding method is shown below.

In the case of forming a mirror-like or mat-like molded product by the injection molding method, it is more preferable that the thickness of the heat insulating layer is 0.1 to 0.5 mm and the thickness of the metal layer is 1% of the thickness of the heat insulating layer.
/ 5 or less and 2 to 40 μm. Particularly preferably, the thickness of the heat insulating layer is 0.12 to 0.3 mm, the thickness of the metal layer is 1/100 to 1/10 of the thickness of the heat insulating layer, and 2 to 3 mm.
0 μm.

In the case of molding a grain-like molded product by the injection molding method, the thickness of the heat insulating layer is more preferably 0.1 to 0.5 m.
m, the thickness of the convex portion of the metal layer is 1/5 or less of the thickness of the heat insulating layer and 10 to 50 μm, and the depth of the grain-shaped concave portion is 5 to 40 μm. Particularly preferably, the thickness of the heat insulating layer is 0.12 to 0.3 mm, the thickness of the convex portion of the metal layer is 1/5 or less of the heat insulating layer thickness, and 10 to 40 μm,
The depth of the grain-shaped recess is 5 to 35 μm. If the depth of the concave portion is too large, a large difference tends to occur in the mold surface reproducibility between the concave portion and the convex portion. On the other hand, if the depth of the concave portion is too small, the effect of forming the grain shape is reduced.

When a mirror-like or mat-like molded article is formed by blow molding, it is more preferable that the thickness of the heat insulating layer is 0.3 to 0.8 mm and the thickness of the metal layer is 1% of the thickness of the heat insulating layer.
/ 5 or less and 2 to 50 μm. Particularly preferably, the thickness of the heat insulating layer is 0.35 to 0.7 mm, the thickness of the metal layer is 1/100 to 1/5 of the thickness of the heat insulating layer, and 2 to 40 mm.
μm.

When a grain-like molded article is formed by blow molding, the thickness of the heat insulating layer is more preferably 0.3 to 0.8 m.
m, the thickness of the convex portion of the metal layer is 1/5 or less of the thickness of the heat insulating layer, and 10 to 50 μm, and the depth of the grain-shaped concave portion is 5 to 40 μm. Particularly preferably, the thickness of the heat-insulating layer is 0.3 to 0.7 mm, the thickness of the projections of the metal layer is 1/5 or less of the thickness of the heat-insulating layer, and 10 to 40 μm. 5 to 35 μm.

In the heat-insulating mold of the present invention, when the metal layer surface is matte, the average thickness of the metal layer is defined as the thickness of the metal layer. That is, the thickness from the average line measured by JIS B0601 to the interface with the composite layer is defined as the average thickness. Also,
When the surface of the metal layer is uneven, the thickness from the protrusion of the metal layer forming the grain to the interface with the heat insulating layer is defined as the thickness of the metal layer. When the surface of the metal layer has unevenness in the form of a grain, the thickness of the metal layer convex portion forming the grain shape is set to the metal layer thickness because the mold surface reproducibility of the convex portion is improved and the weld line of the entire molded article is formed. This is for reducing the conspicuousness. The appearance of the grain is preferably such that one of the convex and concave portions is a mirror surface, and the other is a matte surface. The thickness of the metal layer is preferably uniform, and the thickness variation is preferably ± 10% or less, more preferably ± 5% or less. When the surface of the metal layer is uneven, the thickness of the metal layer in the projection or the thickness of the metal layer in the depression is preferably uniform. The variation of each thickness is preferably ± 10% or less, more preferably ± 5% or less. If the thickness of the metal layer varies greatly, the mold surface reproducibility of the thick portion of the metal layer deteriorates, and the portions having good and poor mold surface reproducibility appear on the same molded product surface, which tends to cause unevenness.

In the heat insulating mold, between the heat insulating layer and the base mold,
Alternatively, the cause of peeling between the heat insulating layer and the metal layer is not only the difference in thermal expansion coefficient, but the difference in thermal expansion coefficient is a major factor. The adhesion between the heat insulation layer and the metal mold and metal layer is large,
In the case of a heat insulating layer having a low elastic modulus and a high elongation at break, peeling does not occur even if the difference in thermal expansion coefficient is slightly large. However, a material suitable for the heat-insulating layer, that is, a heat-insulating material having high heat resistance and high hardness generally has a large elastic modulus, and particularly a heat-resistant synthetic resin having an aromatic ring in the main chain. To make the heat-resistant synthetic resin layer adhere to the base mold and / or the metal layer to prevent peeling, it is preferable that the difference in thermal expansion coefficient is small.

In injection molding, blow molding, and the like, the mold surface that comes into contact with the heated resin to be molded is subjected to a severe cooling / heating cycle every molding. In general, the metal layer has a smaller coefficient of thermal expansion than the heat insulating layer made of a heat-resistant polymer, and has a significantly different coefficient of thermal expansion. Therefore, stress is repeatedly generated at the interface every molding,
It causes peeling. Separation can be suppressed by reducing the difference in the coefficient of thermal expansion between the metal mold and the heat insulating layer and between the metal mold and the heat insulating layer that are in contact with the heat insulating layer.

In the heat-insulating mold of the present invention, the difference between the coefficient of thermal expansion of the base mold and the metal layer in contact with the heat-insulating layer and the coefficient of thermal expansion of the heat-insulating layer should be less than 4 × 10 ⁻⁵ / ° C. This is preferable in terms of resistance to cooling and heating cycles. More preferably, it is less than 3 × 10 ⁻⁵ / ° C. In general, metals have a smaller coefficient of thermal expansion than polymers, so it is preferable to select a heat-resistant polymer having a small coefficient of thermal expansion.

The coefficient of thermal expansion described here is a coefficient of linear expansion. The coefficient of thermal expansion of the heat-insulating layer is a coefficient of linear expansion in the surface direction of the heat-insulating layer and is measured by a method described in JIS K7197-1991, and is an average value between 50 ° C and 250 ° C, or a glass transition of the heat-insulating layer. If the temperature is below 250 ° C,
It is shown as an average value between 50 ° C. and the glass transition temperature. That is, a heat insulating layer is formed on a flat metal plate, and then the heat insulating layer is peeled off, and the average thermal expansion coefficient of the heat insulating layer between 50 ° C. and 250 ° C. or between 50 ° C. and the glass transition temperature. Is measured.

The metal of the base mold which can be used favorably in the present invention,
Table 1 shows the coefficients of thermal expansion of the metal of the metal layer covering the outermost surface, the heat-resistant polymer of the heat insulating layer, and the general synthetic resin.

[0060]

[Table 1]

* Carbon fiber is blended in these resins
The thermal expansion coefficient to 4 × 10 ^-FiveLow to around / ℃
Can be reduced. Also, the coefficient of thermal expansion of the base mold and metal layer is large.
As the temperature increases, a heat insulating layer with a relatively large coefficient of thermal expansion is used.
it can. Steel is the most commonly used mold material
However, aluminum alloys and zinc alloys have recently been used. Book
In the invention, the closer the coefficient of thermal expansion is, the more preferable,
When steel is used, the coefficient of thermal expansion is extremely small.
Thermal expansion type polyimide or the like can be used particularly preferably.

Next, the preferred range of the structure of the end face of the heat insulating mold of the present invention will be described. 1 and 2 show specific examples of the structure of the end face portion. The size of each part is as follows. s1 and s2 are the thickness of the metal layer, and the preferred range is 1 to 300 μm. d1 and d2 are thicknesses of the heat insulating layer, and a preferable range thereof is 0.05 to 3 mm.
It is.

D0 is the height of the embankment, and its range is 0/100 to 99/100 of the thickness of the heat insulating layer, preferably 20
/ 100 to 99/100, particularly preferably 50/100
~ 90/100. When d0 is small, the durability of the mold end decreases, and when d0 is large, the moldability of the mold end,
That is, the mold surface reproducibility and the like are reduced. w1 is the width of the embankment (shown by the top surface), and its preferred range is 0.
1 to 10 mm, more preferably 0.2 to 5 mm,
Particularly preferably, it is 0.3 to 1 mm. If the width is too narrow, the durability of the end of the mold is significantly reduced. If the width is too wide, the heat insulating property of the mold and, consequently, the moldability, that is, the reproducibility of the mold surface and the like are undesirably reduced.

Although b1 usually has a relationship of b1 = d1-d0, it will differ slightly depending on the thickness of the metal layer at the bank. At least b1 is 1/100 or more of the thickness of the heat insulating layer,
It is preferably from 1/100 to 80/100, particularly preferably from 10/100 to 50/100. e1 and e2 are the notch widths at the end surface of the heat insulating mold, and are the clearance widths of the forming mold matching portions. By providing the clear lance, the durability of the heat insulating mold is significantly improved. e1 and e2 are 2 to 200 μm, preferably 5 to 100 μm
m, particularly preferably in the range of 10 to 70 μm. If this value is smaller than 2 μm, the metal layer directly hits or rubs at the joint portion or the like, which may cause deformation or destruction of the mold heat insulating layer, which is not preferable. If it exceeds 200 μm, molding problems such as burrs at the joint are noticeable, which is not preferable.

F1 and f2 are notch depths of the mold. The depth can be selected widely within the range of not less than the thickness of the metal layer and less than the thickness of the base mold, but is preferably 3/4 of the thickness of the metal layer to 3/4 of the thickness of the mold, and particularly preferably 2 to 10 m.
m. If it is too shallow, the durability of the coating layer on the end face decreases, which is not preferable. If it is too deep, the contact area of the mold mating portion becomes small, and the strength of the base mold decreases, which is not preferable.

In order to effectively utilize the performance of the heat insulating mold of the present invention to mold a synthetic resin, it is important to select the mold temperature conditions. Preferably, the mold temperature is set at room temperature to (softening temperature of synthetic resin−20 ° C.). More preferably (room temperature +5
(° C.) to (softening temperature of synthetic resin−30 ° C.). With such a mold temperature, a molded article having excellent reproducibility of the mold surface shape and excellent appearance can be obtained. The mold temperature described here is a temperature at the time of molding the base mold in a portion in contact with the heat insulating layer. If the mold temperature is higher than this range, the molding cycle becomes longer, and if the mold temperature is lower than room temperature, dew condensation or the like occurs on the mold surface, which is not preferable.

The synthetic resin which can be molded by the molding method using the heat insulating mold of the present invention is a thermoplastic resin which can be used for general injection molding and blow molding. For example, polyethylene,
Examples include polyolefin such as polypropylene, polystyrene, styrene-acrylonitrile copolymer, rubber-reinforced polystyrene, styrene-based resins such as ABS resin, polyamide, polyester, polycarbonate, methacrylic resin, vinyl chloride resin, and polyphenylene ether.

The synthetic resin may contain 1 to 60% by weight of a resin reinforcement. Various types of rubber,
Various fibers such as glass fiber and carbon fiber; and inorganic powders such as talc, calcium carbonate and kaolin. The heat-insulating mold of the present invention can be particularly effectively used for rubber-reinforced polystyrene resin, polyamide resin such as nylon 66 and nylon 6, and acrylonitrile having a high acrylonitrile content.
Styrene copolymer, A using the copolymer as a matrix
BS resin and various synthetic resins having a glass fiber content of 15 to 60% by weight.

The concept of the basic principle of the effect of improving the moldability of the heat insulating mold of the present invention will be described below. The heat-insulating mold has a mold surface covered with a heat-insulating layer. For example, when a heated resin injected into the surface contacts the surface during injection molding, the surface of the mold is heated by the heat of the resin. Therefore, the larger the heat insulating property of the heat insulating layer is, the higher the mold surface temperature is, and the moldability is improved as in the case where the mold temperature is increased.

The injection molding method using the heat insulating mold of the present invention can be combined with other various molding techniques by utilizing the principle. For example, a combination with low-pressure injection molding, such as gas-assisted injection molding or injection compression molding, in which the pressure at which the synthetic resin presses the mold wall surface during molding and / or the flow rate of the synthetic resin in the mold is low is also included. In addition, when used in various blow molding methods, the improvement effect is particularly exhibited when the parison is used for blow molding in which the time from when the parison contacts the mold surface to when the blow pressure is sufficiently applied to the inner surface of the molded product is long. .

The heat insulating mold of the present invention can be used for, for example,
Housing for electronic equipment, office equipment, various automotive parts,
It can be used for molding general synthetic resin injection molded products such as various daily necessities and various industrial parts. In particular, when used in housings of electronic equipment, electrical equipment, office equipment, etc., in which weld lines are likely to appear, effects such as elimination of post-processing such as painting and reduction of manufacturing costs can be achieved due to extremely excellent mold reproducibility and appearance. .

Further, in order to make use of the mold reproducibility and appearance characteristics, which are the features of the molding method using the heat insulating mold of the present invention, the metal surface state of the heat insulating mold coating layer, in particular, the grain state, etc., can be improved more effectively. For reproduction, it is preferable to increase the draft angle compared to a conventional metal mold. However, in general, when molding a housing of a household appliance or office equipment, there is a problem in increasing the draft angle in design. In such a case, it is preferable that the split mold has a split surface on the mold cavity surface on which the heat insulating layer and the metal layer are stacked, and has a bank structure at an end portion of the base mold forming the split surface. .

A split mold having a split surface on a cavity surface of a mold in which such a heat insulating layer and a metal layer are laminated can be used for removing a molded product from a housing of a light electric device, an electronic device, an office device, etc. It can be used particularly preferably when molding a housing having a depth of 10 cm or more, more preferably 15 cm or more.

[0074]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. The production method and the types of characteristics of the metal layers in the present embodiment are summarized below. Metal layer A: Low-phosphorus chemical nickel plating with a low phosphorus content formed by performing chemical nickel plating at a low temperature, in a weakly alkaline state and at a low speed using sodium hypophosphite as a reducing agent.

Metal layer B: using sodium hypophosphite as a reducing agent
Medium phosphorus chemical nickel plating with relatively high phosphorus content formed by chemical nickel plating at high temperature, acidic condition, and high speed. Metal layer C: high-phosphorus chemical nickel plating with a high phosphorus content formed by performing chemical nickel plating at a high temperature, in an acidic state and at a high speed using sodium hypophosphite as a reducing agent. Metal layer D: Semi-bright electrolytic nickel plating with low sulfur content.

Metal layer E: Bright electrolytic nickel plating with a high sulfur content. Metal layer F: copper strike plating using copper sulfate Metal layer G: electrolytic copper plating using copper sulfate plating bath The thermal expansion coefficient of each of the above nickel plating layers is approximately 1.3 × 10 ⁻⁵ / ° C. .

[0077]

Embodiment 1 Manufacturing method of heat-insulating mold (1) Mold structure This is a mold for injection molding of a housing-shaped molded body (housing) made of steel (S55C). The coefficient of thermal expansion of the mold is 1.1 × 1
0 ^-5 / ° C. As shown in FIG. 5, the fixed side mounting plate I,
A cavity G is surrounded by the split block J, the movable side plate K, and the core L. The cavity surfaces of the fixed side mounting plate I and the split block J are laminated with a heat insulating layer, and are composed of a base mold, a heat insulating layer, and a metal layer. The split surfaces between the split mold blocks and between the split mold blocks and the fixed-side mounting plate I have the end face structure according to the present invention. The heat-insulating layer-coated surface of the base mold is overlaid with copper-nickel-chrome plating. (2) Heat-insulating layer Primer layer: A linear polyimide precursor having a high content of CO group as a primer on the surface of the base mold of split mold block J
A solvent solution mainly containing 0% by weight of N-methylpyrrolidone was sprayed to a thickness of about 1 μm, dried at 160 ° C. for 20 minutes, and partially imidized. Thermal insulation layer: Wholly aromatic polyimide varnish (Trenice # 3000, manufactured by Toray Industries, Inc.) on the primer
Was repeatedly spray-coated. After each spray coating, heating was performed at 160 ° C. for 20 minutes. This coating and heating were repeated to obtain a thickness of 200 μm. Etching aid-containing layer: To form a composite layer, 11.0 parts by weight of titanium oxide dispersed in 100 parts by weight of titanium oxide was used as an etching aid to make a composite layer.
0, and the outermost surface is coated with an etching aid-containing layer having a thickness of 10 μm.
To complete the polyimide layer. (3) Plating method Etching method: The mold covered with the obtained heat insulating layer was etched using a mixed solution of potassium dichromate and sulfuric acid with stirring. Plating method: Sensitize the heat insulation layer surface of the obtained mold,
The metal layer A having a thickness of 0.5 μm is coated by performing a treatment in the order of the activation process and then performing chemical nickel plating, and a 1 μm metal layer F, a 4 μm metal layer G, and a 5 μm metal layer D are formed on the surface. Coated, and a metal layer E 15 μm
Was coated. (4) Pattern etching method: An etching pattern grain was cut on the entire surface of the cavity of the obtained metal layer-coated heat insulating mold by a known etching method. The average depth of the etched portion with respect to the mirror surface was about 10 μm. (5) The heat-insulating mold thus produced had the end face structure as shown in FIG. The structure of each part is as follows. d1: 200 μm in the thickness of the heat insulating layer s1: 25 μm in the thickness of the metal layer d0: 170 μm in the height of the bank b1: 30 μm in the thickness of the heat insulating layer at the end face w1: 0.3 mm at the top width of the bank e1: Notch width 1. 50 μm f1: 10 mm at notch depth Performance evaluation of heat insulation mold Using the obtained heat insulation mold, a rubber-reinforced polystyrene resin (trade name of Asahi Kasei Polystyrene 492, manufactured by Asahi Kasei Kogyo Co., Ltd.) was injected as a thermoplastic resin at a molding temperature of 230 ° C and a mold temperature of 30 ° C. Molding was performed. Table 2 shows the obtained results.

[0078]

Second Embodiment A heat insulating mold structure similar to the first embodiment except that the shape of a bank provided in contact with an end face is changed. The structure of each part is as follows. d1: 200 μm in the thickness of the heat insulating layer s1: 25 μm in the thickness of the metal layer d0: 100 μm in the height of the embankment b1: 100 μm in the thickness of the heat insulating layer at the end face w1: 1.0 mm in the top width of the embankment e1: Notch 55 μm in width f1: 10 mm in notch depth Using this, the results of molding evaluation in the same manner as in Example 1 are shown in Table 2.
Shown in

[0079]

Embodiment 3 A heat-insulating mold structure similar to that of Embodiment 2 is prepared except that the copper plating layer is eliminated and the metal layer D is replaced with the metal layer B and the metal layer E is replaced with the metal layer C. That is, the configuration of the plating layer is an ABC structure. The structure of each part is as follows. d1: 200 μm in the thickness of the heat insulating layer s1: 25 μm in the thickness of the metal layer d0: 170 μm in the height of the bank b1: 30 μm in the thickness of the heat insulating layer at the end face w1: 0.5 mm at the top width of the bank e1: Notch width Table 1 shows the results of molding evaluation using this as described in Example 1.
Shown in

[0080]

Fourth Embodiment A heat insulating mold structure similar to that of the first embodiment except that the structure of the mold end surface is changed to the structure shown in FIG. The structure of each part is as follows. d2: 200 μm in the thickness of the heat insulating layer s2: 25 μm in the thickness of the metal layer e2: 50 μm in the notch width f2: 10 mm in the notch depth Table 2 shows the results of the molding evaluation using this as in Example 1.
Shown in

[0081]

Comparative Example 1 The end face structure of the split block J is as shown in FIG. Otherwise, the heat insulating mold structure is the same as that of the first embodiment. The structure of each part is as follows. d3: 200 μm in the thickness of the heat insulation layer s3: 25 μm in the thickness of the metal layer
Shown in

[0082]

Comparative Example 2 The structure of the end face of the split block J is shown in FIG. Otherwise, the heat insulating mold structure is the same as that of the first embodiment. The structure of each part is as follows. d4: 200 μm in the thickness of the heat insulating layer s4: 25 μm in the thickness of the metal layer w4: 1 mm in the width of the embankment e4: 25 μm in the notch width f4: 10 mm in the notch depth Using this, the molding evaluation was performed in the same manner as in Example 1. Table 2 shows the results
Shown in

[0083]

Comparative Example 3 Table 2 shows the results of molding evaluation using a simple metal mold having no heat insulating layer in the split mold block J in the same manner as in Example 1.

[0084]

[Table 2]

<Evaluation Criteria> Die durability × Part of the heat insulating layer peeled off at the end of the mold after 100 moldings. ○ Deformation of both the mold and the molded body was not practically recognized after 3,000 molding tests.で No deformation was found in both the mold and the molded product after 3000 molding tests.・ Pattern reproducibility XX The pattern reproducibility is extremely poor. C: Pattern reproducibility in the vicinity of the end is extremely poor. The part far away from the end is good. ○ Pattern reproducibility is good, and reproducibility near the end face is almost good. ◎ Good pattern reproducibility over the entire surface. -State of joint part △ In the sample of the 100th molding, a small bulge was observed on the joint part at the joint part.良好 Good after 3,000 moldings, with slight bulging observed at the joint.良好 Good after 3,000 moldings, and the degree of the line at the mating part is recognized.

[0086]

The heat-insulating mold of the present invention has excellent moldability, and also has excellent resistance to severe shear stress and cooling / heating cycle during molding. That is, by molding using this, it is possible to improve the reproducibility of the mold surface shape of the synthetic resin molded article, and to mold a molded article having an excellent appearance such that the conspicuousness of the mold fitting portion can be reduced. Further, the durability of the end face of the mold and the durability of the heat insulating layer are remarkably superior to those of the heat insulating mold in which the heat insulating layer and the metal layer are simply laminated.
As a result, it is possible to avoid problems such as the occurrence of defects in the corresponding portions of the synthetic resin molded product due to deformation and breakage due to repeated molding, mainly at the mating portions and end portions of the mold. it can.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing an example of an end face structure of a heat insulating mold of the present invention.

FIG. 2 is a partial cross-sectional view showing an example of an end face structure of the heat insulating mold of the present invention.

FIG. 3 is a partial cross-sectional view showing an example of an end face structure of a conventionally known heat insulating mold of a comparative example.

FIG. 4 is a partial cross-sectional view showing an example of an end surface structure of a heat insulating mold of a comparative example.

FIG. 5 is a cross-sectional view showing a main part of an injection mold having a split mold part used in Examples and Comparative Examples.

[Explanation of symbols]

 Reference Signs List A Mold base made of metal A 'Die part of base mold B Heat insulation layer made of heat-resistant polymer C Metal layer s1 to s4 Thickness of metal layer d0 Height of levee d1 to d4 Thickness of heat insulation layer b1 Heat insulation layer of dyke Thickness w1, w3 Die top width e1, e2, e4 Die notch width f1, f2, f4 Die notch depth G Cavity H Locate ring I Fixed side mounting plate J Split block K Moving side plate L Core M Spool bush N Angular pin O Spool

Claims (12)

[Claims] 1. A heat-insulating mold in which a heat-insulating layer made of a heat-resistant polymer and a metal layer are sequentially laminated on a surface of a mold constituting a mold cavity of a metal base mold. A heat insulating mold having a notch having a width in the range of 2 to 200 μm. 2. The heat-insulating mold according to claim 1, wherein the heat-insulating mold is a split mold having a split surface on a mold cavity surface. 3. The heat-insulating mold according to claim 1, wherein the base mold has a bank structure. 4. The heat insulating layer according to claim 1, 2 or 3, wherein the thickness of the heat insulating layer is in the range of 0.05 to 3 mm, the thickness of the metal layer is in the range of 1 to 300 μm, and not more than ３ of the thickness of the heat insulating layer. Insulation mold. 5. The width of the bank structure of the base mold is 0.1 to 10 mm.
And the height is 20/100 to 99 of the thickness of the heat insulating layer.
The heat insulating mold according to claim 3 or 4, wherein the ratio is in the range of / 100. 6. The notch at the end face of the heat insulating mold has a width of 5 to 5.
The thickness of the metal mold is 100 μm and the depth is not less than the thickness of the metal layer and not more than ／ of the thickness of the base mold.
3. The heat-insulating mold according to 3, 4 or 5. 7. The heat-resistant polymer according to claim 1, wherein the softening temperature is higher than the molding temperature and 140 ° C. or higher.
7. The heat-insulating mold according to 5 or 6. 8. The method according to claim 1, wherein the metal layer is a metal layer formed by chemical plating and / or electroplating.
The heat insulating mold according to 3, 4, 5, 6, or 7. 9. The heat-insulating mold according to claim 8, wherein the metal layer is formed by sequentially laminating chemical nickel plating, chemical and / or electric copper plating, and chemical and / or electric nickel plating. 10. The heat insulating mold according to claim 1, wherein the heat resistant polymer constituting the heat insulating layer is polyimide. 11. The method of claim 1, 2, 3, 4, 5, 6, 7,
A resin molding method for molding using the heat insulating mold according to 8, 9 or 10. 12. The resin molding method according to claim 11, wherein a housing for a household appliance or office equipment is molded.