JPS63270105A - Manufacture of resin mold - Google Patents

Abstract

PURPOSE:To manufacture easily a simple mold where cracks are not generated on the surface of a resin mold and it is superior in heat resistance, by a method wherein a base material selected out of carbon, glass, quartz and invar is arranged on the surface of a metallic core and cyanic acid ester resin composition is used as a liquid thermosetting resin composition to be used for casting. CONSTITUTION:This is a manufacturing method of resin mold where a material obtained by arranging a base material selected out of carbon, glass, quartz and invar on the surface of a metallic core is used and cyanic acid ester resin composition, which is indispensably composed of cyanate resin (a) or the said cyanate resin (a) and polyfunctional maleimide or epoxy resin (c) and is liquid at a temperature of 100 deg.C or lower, is used. The title method is performed under a state where a casting temperature falls within a range higher than the normal temperature and 100 deg.C or lower and viscosity of a liquid cyanic acid ester resin composition falls within a range of 1.0X10<2>-1.0X10<3> poise, in a preferable enforcement mode. A resin mold or a mold for manufacturing a sand mold for casting where the thermosetting resin composition containing at least metallic pulverulent body is fixed on the surface of a metallic core and crack resistance is improved can be manufactured.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is suitable for molding plastics, filled plastics, etc. by compression molding, transfer molding, injection molding, vacuum forming, and other methods. This is a method for producing resin molds with improved crack resistance, molds for producing sand molds for casting, etc., in which a thermosetting resin composition containing at least metal powder is fixed on the surface of a metal core used.

[Conventional technology and its problems]

Conventionally, the method for producing a resin mold in which a thermosetting resin composition containing at least metal powder is fixed on the surface of a metal core involves preparing a liquid thermosetting resin composition for casting that has been sufficiently vacuum degassed. This was injected between the casting model containing the product master and the metal core by pressurization, press-fitting, or other methods.

In the case of this method, if the resin mold is large or the resin layer to be cast is thick, the casting resin tends to crack easily. This problem is likely to occur in the case of resin molds, and improvement of this problem has been desired.

[Means for solving problems]

As a result of intensive studies to solve this problem, the present invention has been developed by disposing a base material selected from carbon, glass, quartz, invar, etc. on at least the surface of the metal core, and by disposing a base material selected from carbon, glass, quartz, invar, etc. The inventors have completed the present invention by discovering that the use of a cyanate ester-based resin composition provides a significant improvement.

That is, in the present invention, a casting model having a releasable surface formed by temporarily fixing a product master and a metal core serving as the core of the mold are fixed to each other with a desired gap, and a metal is inserted into this gap. After filling the liquid thermosetting resin composition containing powder,
In a method for manufacturing a resin mold, the thermosetting resin composition is cured and then the model for casting is removed to form a desired resinous mold surface on the surface of the metal core. A base material selected from carbon, glass, quartz, and invar is used, and
The liquid thermosetting resin composition contains (a) a cyanato resin, or (a) and (b) a polyfunctional maleimide, or (c) an epoxy resin as essential components, and is liquefied at a temperature of 100° C. or lower. This is a resin mold manufacturing method characterized by using a cyanate ester resin composition of
℃ or less, the viscosity of the liquid cyanate ester resin composition is 1.0 x 102 to 1.0 x 1. It is characterized by being carried out within the range of 0x103 voices.

The configuration of the present invention will be explained below.

The production of resin molds is based on a model of a product whose surface has mold releasability (
Set the product master (hereinafter referred to as the product master) in a casting mold (hereinafter referred to as the casting model), place the metal core on the opposite side with the desired gap, and attach the casting aid. After mounting and forming a casting mold, a liquid curable resin composition is poured into this gap, the resin is pre-cured or hardened, the resin is removed from the casting mold, the product master is removed, and the product master is removed. A resin mold is obtained by post-curing (completely curing) to transfer the shape, surface, etc. of the product master, and desired auxiliary jigs are set in this resin mold.

In the method of the present invention, a metal core is used, and a base material selected from carbon, glass, quartz, invar, etc. is arranged on the surface of the metal core (see (b) below). c)) and the use of a cyanate ester resin composition as the liquid thermosetting resin composition for casting ((f) below).

First, the materials and equipment used in the resin mold manufacturing method of the present invention are as follows.

(a) Product master: The target molded product itself or a mold of the same type as the target molded product, and the material can be dry-cured wood, synthetic wood, plaster, ABS, as long as it can withstand temperatures of about 100℃. It may be made of resin, silicone resin, acrylic resin, epoxy resin, iron, aluminum, copper, or any other material, but materials with good workability such as wood, plaster, and resin are preferred.

(b), Metal core: The thickness range of the casting resin forming the surface layer is 1 to 50 mm,
The metal surface is preferably processed into a shape having a thickness in the range of 2 to 10 mm, and a fixing part for casting, a fixing part to a mold frame, etc. are formed as appropriate. Although various metals can be used, aluminum alloy materials are preferred from the viewpoint of the relationship between the coefficient of linear expansion of the casting resin and the metal core, as well as ease of casting and machining. Surface treatments are also used to improve adhesion.

(c) Base material selected from carbon, glass, quartz, invar, etc.: The base material selected from carbon, glass, quartz, invar, etc. is a base material selected from carbon, glass, quartz, invar, etc. There are no particular limitations on the thickness, but it should be selected so that it does not interfere with the casting process. The method for placing the base material on the surface of the metal core is not particularly limited, but preferably,
A composition of a thermosetting resin composition of the same type as the liquid cyanate ester thermosetting resin composition for casting of the present invention and a fiber chopped base material of the present base material is prepared, and this is applied to the surface of the metal core. Brushing and spraying are methods of placing by painting or other methods; simply cut genuine leather paper, woven fabric, or non-woven fabric into the desired shape, and apply the same type of material or a liquid for casting to the desired part of this. A method of temporary adhesion and placement using a cyanate ester resin composition as an adhesive; paper, woven fabric, or non-woven fabric made of genuine leather is cut into the desired shape, and this is liquid heat-cured for casting. A method in which a solvent-containing composition consisting of a thermosetting resin composition or a thermosetting resin composition of the same type as this is applied to the entire surface by brushing, dried, temporarily adhered, and placed; paper made of genuine leather, A prepreg is obtained by impregnating a woven or nonwoven fabric with a liquid cyanate ester resin composition for casting or a similar cyanate ester resin composition diluted with a solvent or as it is, and drying as appropriate. Any method may be used, such as a method of bringing it into close contact under heat or heating.

(d) Other auxiliary materials such as metal inserts, fillers, mold release agents, coupling agents, etc.: Holes, protrusions, other parts with narrow areas, parts of sprues in injection molds, etc. cannot be filled with resin alone. Because of the lack of strength, metal inserts are usually used.

If a wooden mold or the like is used and an uneven pattern on the surface is unnecessary, use a filler to level the surface and use a mold release agent to release the casting resin.

Also, depending on the auxiliary components of the thermosetting resin composition used for casting, the adhesion to the metal core may be poor, so adhesion auxiliaries such as silane coupling agents and titanate coupling agents may be used as appropriate. .

(e), Model for casting: Sometimes the product master itself is used, but usually,
It consists of a part of the mold cavity in which the product master is attached and its surroundings, and the surface is coated with a mold release agent depending on the type of liquid thermosetting resin composition used for casting. The surrounding material may be the same as the product master, but it is convenient to use room-temperature curing gypsum, silicone resin, etc.; Preferably, the product master is temporarily fixed with resin or the like.

Furthermore, it is preferable to place the base material on the surface of this model in the same manner as the metal core, as long as it does not interfere with the casting operation.

(f) Liquid thermosetting resin composition for casting: 1×1 at a temperature of 100°C or less containing metal powder as an essential component
02~1x103 poise, preferably 3x102~6x
A solvent-free cyanate ester liquid thermosetting resin composition (cyanato resin, cyanate ester-epoxy resin, cyanate ester-maleimide resin, cyanate ester-maleimide-epoxy resin, etc.) in the range of 102 poise. .

Further, the metal powder includes aluminum, copper, nickel, iron, stainless steel, other metals, and mixtures thereof, and the amount of metal powder blended is usually selected from the range of 20 to 70% by volume.

These include low molecular weight thermosetting resin monomers to adjust the viscosity of the resin as appropriate, rubbery polymers and non-quality resins as flexibility imparting agents, thickeners, antifoaming agents, and surfactants. In addition, inorganic powders such as silica, boron nitride, wollastonite, talc, palladium oxide, copper oxide, and magnesium oxide, and fibrous materials such as alumina fiber, silica fiber, and carbon fiber may be mixed. be.

In particular, the liquid thermosetting resin composition for casting of the present invention is preferably used as a two-component resin composition prepared in advance consisting of a resin composition and its curing agent composition. For example, a resin composition (resin Composition (1) is prepared, and an epoxy resin composition (curing agent composition (2)) containing a metal that serves as a curing agent for the cyanate ester resin composition is mixed therein at a temperature ranging from room temperature to 100°C or less. A method of preparing and using a composition for casting is preferred. In this case, the preparation of the composition is preferably carried out under vacuum suction, or the composition is preferably degassed by vacuum suction while stirring.

(Auxiliary materials for casting: Tapes and other sealing materials for sealing the surrounding area for casting by press-fitting with compressed air, suction by vacuum suction, or other means, liquid thermosetting resin compositions for casting. A container, a conduit thereof, a stirrer, a vacuum pump, etc. for preparing the liquid thermosetting resin composition are appropriately used.

(Company), dryer or oven: Used for pre-curing and curing of resin molds.

(i) Auxiliary material for mold assembly: A mold frame (die set or mold base) made of iron, iron alloy, aluminum alloy, etc. for fixing the resin mold is usually used as an auxiliary material.

The resin mold of the present invention is manufactured using the above components. An example of how to use a split mold for injection molding with a metal core to create a casting model is as follows: (1) Set of casting models: Place the metal core and let it harden at room temperature. The product master is fixed with adhesive plaster, silicone resin, etc., a mold release agent is applied, and metal inserts are set as appropriate to create a casting model.

The metal core on the opposite side of the casting model, in which the main base material has been arranged in advance, is fixed at a predetermined interval using a previously prepared position fixing part or a position fixing jig.

(2) Set of casting parts: Set or form the casting resin introduction sprue, vacuum suction part, air vent part, etc., seal the sides and other parts with tape or putty, etc., and prepare the parts for casting. The resin reservoir and the sprue are connected with a tube or the like, and a suction section using compressed air or a vacuum pump is installed.

(3) Casting work: After preparing a predetermined amount of the liquid cyanate ester thermosetting resin composition for casting of the present invention and introducing it into the resin reservoir for casting, a compressor or vacuum pump is turned on. Turn it on and start casting.

As the casting process progresses and the resin rises to the air vent or vacuum suction member, close the injection cock, etc., and fill the resin with the gap 1.
Confirm that this has occurred and stop the injection. Then, remove the injection tube, vacuum suction tube, etc.

(4) Pre-curing: Place in a dryer etc. set at a temperature of 100°C or less,
Pre-cure.

(5) Demoulding: After preliminary curing, the metal core to which the product master is fixed with room-temperature-curable plaster, silicone resin, etc., and the room-temperature-curable composition are removed, leaving the product master behind.

(6) Manufacturing the opposite side resin mold: After cleaning the surface of the product master and the surface of the pre-cured casting resin, apply a mold release agent and use this as the opposite side casting model.

The surface of the metal core is also cleaned.

Next, operations (1) to (5) are performed to produce a pre-cured resin mold on the opposite side.

(7) Ato-curing: Remove the product master from the pre-cured resin mold created above and place in a dryer or the like for ato-curing.

(8) Finishing: Part of the ejector pin and sprue is machined, and the mold surface is finished as appropriate to finish the mold.

An example of the method for producing a resin mold according to the present invention has been described above, and the method according to the present invention is characterized by vacuum-suction casting of a thermosetting resin composition for casting. Except for the use of casting models and other methods of creation, there are no particular limitations.

〔Example〕

The present invention will be explained below with reference to Examples.

Example 1 A chemically modified ABS resin containing wood powder is cut, and the back surface is flat and the surface is uneven with a height of 1 to 5 mm and a width of 2 to 1 mm.
50 with a half-finished striped pattern that is sequentially changed within a range of 0mm.
0mm(L) x150mm(%ll) x20mm
A rectangular parallelepiped (D) was created and used as a product master.

700mm (L) x 250mm (W) x 4
Prepare two aluminum plates with a diameter of 0 mm (D), and place a 510 m
m (L) x 170mm (W) x 20mm (
The depressions in D) were formed by cutting, and holes were formed in the squares of both aluminum plates.

Temporarily adhere the product master created above to the center of the aluminum plate that does not have a recess, and apply a mold release agent (manufactured by Free Coat, USA) to the surface of the product master and aluminum plate.
A casting model was prepared by applying Free Coat 44) (trade name).

In addition, a glass nonwoven fabric (trade name: EP 4050 thickness 2
00 Powder (manufactured by Nippon Vilene Gl) were cut into square parts so as to partially overlap and were partially temporarily adhered with the liquid thermosetting resin composition for casting described below.

Next, the casting model and the glass non-woven fabric arranged aluminum plate were fixed via a spacer with a thickness of 3 cm, and this was placed on a stand with the long sides of the two aluminum plates vertical and horizontal stripes of the striped pattern of the product master. They were arranged so that the one with the least unevenness was on the bottom.

A 20mm thick acrylic resin 20
A box with an outer diameter of 0 mm x 50 mm x 60 mm (tl) with a hole in the bottom and a box with a vacuum rubber tube fixed to it, and a box with an inner diameter of 10 m in the gap on the bottom surface.
mφ acrylic resin pipe was cut in half over a length of 250 mm, and a rubber tube with a cock attached in the middle was attached to the uncut end, and the contact area between the top surface and the box, and the acrylic resin pipe and Polyethylene terephthalate adhesive tape (AI
RTECII INTBRNATIONAL, INC.
The bag was completely fixed and sealed with G5213 high-tack vacuum bag sealant tape (manufactured by .

As a liquid cyanate ester thermosetting resin composition for casting, 23 parts of 2,2-bis(4-cyanatophenyl)propane, 3 parts of bis(4-maleimidophenyl)methane, and bisphenol A type epoxy. Resin (trade name: Epicote 828, Epoxy Sight 184-194, Yuka Shell Epoxy Gl) 3 parts, 150 mesh copper powder 15
A sample having a viscosity of 300 to 800 PS (at 40 to 60°C) was prepared by using 55 parts of aluminum powder of 150 parts and 150 meshes as a main component and blending other components such as a catalyst and an antifoaming agent.

While keeping the temperature at 40 to 60°C, place the tip of the lower casting sprue rubber tube of the casting mold assembled above into the liquid thermosetting resin composition for casting, and vacuum suction from the upper part. and (10
mmHg), after filling the upper box with resin until it overflows, close the rubber tube cock, disconnect the piping from the vacuum pump and stop vacuum suction, and then heat at 60℃ for 4 hours at 80℃,
It was held for 6 hours to pre-cure.

Preliminary (liB hardening) The box body of the hardened soil part, the rubber tube at the bottom, other vacuum seal parts, and excess resin were removed.

Next, after removing the fixture and removing the aluminum plate, the pre-cured resin and the surface of the product master were cleaned, and the same mold release agent was applied as a casting model. was cleaned, a glass nonwoven fabric was placed in the same way, and the same process as above was repeated using it as a metal core to pre-cast and pre-cure the resin mold on the opposite side.

Remove the product master from the resin mold obtained above and heat to 175°C.
After curing for 10 hours, the mixture was cooled to room temperature over 3 hours.

At this time, no cracks were observed on the surface of the resin mold.
Moreover, after heating the obtained resin mold to 180°C, it was allowed to cool, but no cracks were observed, and the glass transition temperature of the resin was 150°C or higher.

Auxiliary tools such as a guide pin, a resin injection port, and a knockout pin were attached to the pair of molds obtained above, and the molds were fixed to a die set to obtain a mold for injection molding.

Using this resin mold, 100 shots of polycarbonate resin were injection molded at an injection pressure of 900 kg/crI and an injection temperature of 280° C., but no abnormalities such as cracks were observed on the surface of the resin mold.

Example 2 Similar to Example 1, a glass nonwoven fabric prepreg impregnated with the following thermosetting resin composition for adhesives was used instead of the glass nonwoven fabric, and this was heat-pressed onto an aluminum core. Otherwise, a good resin mold and molded product were obtained.

Preparation of glass nonwoven prepreg: 2.2-t-s(4-cyanatophenyl)propane 75
0 part was pre-reacted at 160°C for 4 hours to form a prepolymer, and to this was added a non-grade thermoplastic saturated polyester resin (trade name: Polyester-LP 035, Nippon Gosei Kagaku Kogyo G).
Manufactured by @, number average molecular weight calculated from the number of terminal groups: 16,00
0, hydroxyl value 6 mg KOH/g) 250 parts, bisphenol A type epoxy resin (trade name: Epicote 8
28, epoxy equivalent 184-194, Yuka Shell Epoxy (manufactured by GE) was added, dissolved and mixed in methyl ethyl ketone, and the solution with a concentration of 60% was impregnated into a glass nonwoven fabric.
It was prepared by drying at 0-150°C.

Example 3 In Example 1, instead of temporarily adhering the glass nonwoven fabric, the thermosetting resin composition solution for the adhesive used in Example 2 was applied with a brush to the glass nonwoven fabric placed on the aluminum core, and dried. Good resin molds and molded products were obtained using the same method except that a resin mold made of aluminum was used.

Example 4 In Example 1, a glass woven fabric (
Product name: #251, thickness 100ρ, weight 104g
A good resin mold was obtained and a good molded product was obtained in the same manner except that a resin molding machine (Asahi Chevelle, manufactured by Asahi Chevelle ■) was used.

Example 5 A good resin mold and a good molded product were obtained in the same manner as in Example 2, except that a glass woven fabric prepreg made of the glass woven fabric of Example 4 was used instead of the glass nonwoven fabric prepreg.

Example 6 In Example 1, carbon woven fabric (trade name: Trading Card Cross C02341, thickness 500-1
A good resin mold was obtained and a good molded product was obtained in the same manner except that a resin mold (weight: 400 g/m', manufactured by Toshi ■) was used.

Example 7 A good resin mold and a good molded product were obtained in the same manner as in Example 2, except that a carbon woven fabric prepreg made of the carbon woven fabric of Example 6 was used instead of the glass nonwoven fabric prepreg.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the metal core was cast without a glass nonwoven fabric, but cracks occurred during cooling after post-curing. In addition, this resin mold with cracks is
After heating to 80°C, many new cracks were generated when the sample was allowed to cool.

[Operation and effects of the invention]

As is clear from the above Examples and Comparative Examples, according to the casting method of the present invention, even when a large resin mold is manufactured, no cracks occur on the surface of the resin mold, and a simple mold with excellent heat resistance is produced. The mold can be easily produced and has extremely high industrial significance in the field of simple molds.

Claims (1)

[Scope of Claims] 1. A casting model whose surface has releasability, which is formed by temporarily fixing a product master, and a metal core that is the core of the mold are fixed to each other with a desired gap, and this gap is filled with After filling a liquid thermosetting resin composition containing metal powder, the thermosetting resin composition is cured, and then the casting model is removed to form a desired resin mold surface on the metal core surface. In the method for producing a resin mold formed by forming a resin mold, a base material selected from carbon, glass, quartz, and invar is arranged on the surface of the metal core, and the resin component of the liquid thermosetting resin composition is used. As the method, a cyanate ester resin composition which is liquid at a temperature of 100° C. or lower is used as an essential component of (a) cyanato resin, or (a) and (b) polyfunctional maleimide or (c) epoxy resin. A resin mold manufacturing method characterized by: 2. The casting temperature is higher than room temperature and 100°C or less, and the viscosity of the liquid cyanate ester resin composition is 1.
The method for manufacturing a resin mold according to claim 1, wherein the poise is in the range of 0x10^2 to 1.0x10^3 poise.