JPS62181119A - Mold for high accuracy injection molding - Google Patents

Abstract

PURPOSE:To obtain prominent surface accuracy as compared with the mold of stainless steel series by a method wherein a mold, in which the metallic silicone of high purity is integrated with a reinforcing member through bonding agent, is employed for the mold for injection molding. CONSTITUTION:The outermost surfaces of a male mold and a female mold, which are constituting the cavity part of a mold for injection molding, or the surface contacting with molding resin are formed by metallic silicone 1 having the purity of 99.999% or more and ground with a proper accuracy while the metallic silicone 1 is bonded integrally with a metallic reinforcing member 3 through bonding agent 2. The male mold or the female mold is fitted into the mold to assemble them. The bonding agent for bonding the metallic silicone to the metallic reinforcing member is thermoplastic resin and is cured through crosslinking by heat or catalyst promoting agent. According to another method, the first layer of the bonding agent for bonding the metallic silicone and the metallic reinforcing member, which is cured through crosslinking by light beam at a normal temperature, is integrated with the reinforcing member through another bonding agent. Silane series coupling agent, titanate series coupling agent or the other organic series primer is undercoated on the bonding surface of the metallic silicone to improve bonding property to the thermoplastic resin whereby bonding strength may be improved.

Description

[Detailed Description of the Invention] 3. 1.I and D "Molded products that require ultra-high precision quality, such as plastic lenses and optical discs, can now be easily molded and produced by injection molding. When manufacturing such molded products, the most important factor for improving precision is the precision of the mold, especially the surface precision.The male or female mold used for this purpose is usually made of stainless steel. It is manufactured using metal materials through processes such as machine cutting, polishing, and lapping. However, even though it is called high-precision mold steel, it is an alloy steel, so sometimes surface precision is required in angstroms. The current situation is that microstructural defects are a problem with molds, resulting in a fairly high rate of defects during manufacturing.In addition, stainless steel is difficult to cut (difficult to cut and takes a long time to cut), so molds are difficult to cut. Currently, the manufacturing cost is higher than that of a general mold.In contrast, the metal silicon for semiconductors used in the present invention is used in large quantities as a semiconductor. Metallic silicon can be polished with an accuracy of 5 to 10 angstroms on the surface.Also, metal silicon is easy to polish, has no structural defects, and can be done manually at low cost.

As is well known, the purity of metallic silicon is 99.9.
Since it can be produced up to about 9999999%, it can be said that it has characteristics that far exceed the accuracy required for precision mold members.

If such a member could be used on the surface of the molding part of an injection mold, it would be possible to create an injection mold with an unprecedentedly high-precision surface and significantly reduce mold manufacturing costs. It can be said that what can be done is possible.

Therefore, the inventor of the present invention conducted a thorough study to find out how high a level of surface precision a molded product can be obtained when a metal silicone and reinforcing material are integrated with adhesive and used as an injection mold.9 The present invention was completed after discovering that the mold of the present invention can produce an injection molded product with much superior surface precision compared to the stainless steel molds that have been used in the past.

The metallic silicon used in the present invention can be used for ultra-high precision products such as optical discs if it has high purity, and for general purpose products if it has low purity. The thickness is not particularly limited, but the thickness is 0.3 to 2 mm for flat molded products, and 1 to 10 mm for rounded lens molds.
Thick block products are preferred, and thicker block products can also be used as mold members.

As a thermosetting adhesive, any of the following types can be used: room-temperature-curing, photo-curing, or heat-curing resins, but in general, cold-curing resins are used for injection molding materials that can be molded at low temperatures, and cold-curing resins are used for high-temperature injection molding materials. For the mold, it is preferable to use a heat-curing epoxy adhesive or a high-temperature curing heat-resistant adhesive such as kelimide.

Epoxy resins include bisphenol A type, bisphenol F type, and their halogenated epoxy products - retrusin type, tetrahydroxyphenylethane type, alicyclic type,
Phenol novolac type.

Examples include cresol novolak type, epoxy modified acrylate type, and modified epoxy resins based on these.

Hardening agents include aliphatic amines and aromatic amines.

and polyamine compounds thereof, phenols and cresols, complex compounds of amines, monoacids, acid anhydrides 9, etc. can be used, and one example of each curing agent is as follows.

Diethylenetriamine, triethylenetetramine, diethylaminopropylamine, N-7 minoethylbiperazine, benzyldimethylamine tris(dimethylaminomethyl)phenol.

DMP30-)su(2-ethylhexoate).

Nucphenylenediamine. Diaminodiphenylmethane, diaminodiphenyl sulfone, polyamide resin,
Dicyandiamide, trifluoroborine monomethylamine, menthancyamine, xylylene diamine, ethylmethyl imidazole, phthalic anhydride, dodecyl succinic anhydride, I\xahido aphthalic anhydride, methylnadic anhydride, pyromellitic anhydride Acid, p! ! , aqueous benzophenonetetracarboxylic acid, dichlorosuccinic anhydride, dilorendicic anhydride, and the like.

These epoxy resins and curing agents meet the required performance of adhesives9.
For example, they are combined depending on curing temperature, heat resistance, mechanical properties, etc.

Other adhesives include various thermosetting acrylate resins, such as ethylene glycol dimethacrylate-1, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, propylene glycol dimethacrylate, and dipropylene. Glycol dimethacrylate, tripropylene glycol dimethacrylate, propanediol dimethacrylate, glycerin dimethacrylate.

1.3 butanediol dimethacrylate), 1.4 butanediol dimethacrylate, 1.5 pentanediol dimethacrylate), L, S hexanediol dimethacrylate, neopentyl glycol dimethacrylate-1-
, 1,8 octanediol dimethacrylate, 2.3 dibromneopentyl glycol dimethacrylate, hisphenol A dimethacrylate), 2,2-bis(methacryloyloxypolyethoxyphenyl)propane.

Trimethylolpropane triacrylate, trimethylolmethane trimethacrylate, tetramethylolethane trimethacrylate, tetramethylolmethane trimethacrylate, tetramethylolmethanetetramethacrylate), N N-((22,.1-trimethylhexamethylene)bis(2 -(aminocarboxy)propane-1
, 3-diol) tetramethacrylate, etc. can be used.

Furthermore, the adhesive material may include an inorganic powder filler, a fibrous reinforcing material,
Both are used in combination with metal powder.

The metal reinforcing material is not particularly limited, but W
From the viewpoints of J grade, workability, precision, etc., iron-based steels and stainless steels are the most practical.

Surface treatments using various types of couplings are effective in improving the adhesion between metallic silicon and adhesives. Various coupling agents 9 such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-
methoxyethoxy)silane, N-(2-aminoethyl)3-aminopropylmethyldimethoxysilane, N-(
2-7minoethyl) 3-7minobrobylmethyldimethoxysilane, N-(2-aminoethyl)3-aminopropyltrimethoxysilane, 3aminopropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3- Glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3
-Methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, etc. can be used. Titanium-based coupling agents and various fluoromonomers and oligomers are also effective.

Other measures for improving the adhesion of metallic silicon include metal plating and metal sputtering. Depending on the type of adhesive, if the adhesive strength between metal silicon and the adhesive is low, for example, metal tin plating or brass plating, or thin film deposition of nickel, chromium, or their alloys by sputtering may significantly reduce the adhesive strength. You can do both to improve.

As a result of a thorough study of the technical issues of attaching a silicon wafer to the surface using the above materials and the durability in practical injection molding, 1. We were able to demonstrate that all the problems faced by conventional molds were solved, and as a result, we completed the present invention. EMBODIMENT OF THE INVENTION The structure and effect of this invention will be explained in detail below along with an Example.

A plastic protective coating is applied to one side of a silicon wafer, which has a thickness of 1 mm, a direct diameter of 130 mm, and is polished to a surface accuracy of 5 to 10 angstroms to prevent deterioration. A silane coupling material is applied to one exposed side and heat treated at 110 for 1 hour. The silane coupling treated surface (C surface) is pressed with the adhesive surface of the metal reinforcing material shown in Figure 1 using an epoxy resin adhesive (XD911, manufactured by Ciba Geigy), and then heated at 150°C for 5 hours. After curing, the silicon wafer and metal reinforcing material were integrally bonded.

This mold part was assembled into the fixed side and moving side of the mold base as shown in Figure 2, and was used as an injection mold. Paint a plastic protective coating on one side to prevent scratches. A silane coupling material is applied to one exposed side and heat treated at 110 for 1 hour.

20 g of pentaerythritol triacrylate as a polyfunctional acrylic resin, 0.2 g of benzophenone as an ultraviolet curing agent, and 8 silica powder on the exposed surface of the silicon wafer.
0g, and a photocurable adhesive prepared by blending 0.1g of tertiary amine as an accelerator was applied to a thickness of 0.5mm,
The photocurable resin was cured by irradiating it with ultraviolet rays for 30 seconds.

Next, the cured layer and metal reinforcing material are made of room temperature curable epoxy resin (a combination of bisphenol A type resin and polyamine).
The silicon wafer and reinforcing metal material were bonded together, and this was fitted into the mold space shown in FIG. 2 to form an injection mold. Since all processes in this mold were carried out at room temperature, no deformation was observed in the mold obtained.

A plastic protective coating is applied to one side of a silicon wafer, which is 1 mm thick, 130 mm in diameter, and polished to a surface accuracy of 5 to 10 angstroms, to prevent scratches. Apply silane coupling (A) to one exposed side and heat treat at 110°C for 1 hour.

Mix 15 g of pentaerythritol triacrylate, 0.15 g of benzoyl peroxide, and 85 g of silica powder as a polyfunctional acrylic resin on the exposed surface of the silicon wafer, and mix this with 0.1 g of dimethylaniline to quickly form a thickness of <0.5 mm. Apply to. This material was adhered with room temperature curable epoxy resin in the same manner as in Example 2, and molded into an injection mold made of a silicon wafer polished to a thickness of 1 mm, a diameter of 130 mm, and an area of 5 to IO angstroms. A plastic protection film is applied to one side to prevent scratches.First, metal tin is electroplated to a thickness of 1 micron on the exposed surface, and the surface to which the metal reinforcing material is attached is similarly plated with metal tin to a thickness of 5 microns. Ta. Next, the plated metal surface was heat treated at 190° C. to oxidize it. Both plated layers were bonded together using an epoxy resin adhesive (Araldite AW, manufactured by Ciba Geigy), and the resulting mold component was made into an injection mold in the same manner as in Example 1. In this mold, the adhesion between the metal silicon and the metal reinforcement was significantly improved.

L1 Takumi 1 A plastic protective coating is applied to one side of a silicon wafer, which is 1 mm thick, 130 mm in diameter, and polished to a surface precision of 5 to 10 angstroms, to prevent scratches. Next, apply acrylic silane (KB) dissolved in methanol at 10% to the exposed surface.
M503. Apply a thin layer of 110
This surface and the metal reinforcing material surface were bonded with the epoxy resin used in Example 4, and the resulting mold part was made into an injection mold in the same manner as in Example 1.

1 Metallic silicon with an unpolished surface (130 m in diameter)
m, thickness 3 mm) was adhered to a steel material with an epoxy resin (Araldai AW, manufactured by Ciba Geigy), and then the surface of the metal silicon was polished and wrapped to a mirror surface. After this mold part was molded into a predetermined shape, it was made into an injection molding mold in the same manner as in Example 1.

All the injection molds obtained in Examples 1 to 6 were attached to an injection molding machine, and injection molding was performed using polycarbonate I under the following conditions.

Molding conditions Material temperature: 300°C Mold temperature: 80°C Injection pressure: 1000 kg/c 1112 - Molded product shape Diameter: 130 mm, thickness: 2 mm The mold of the present invention also showed durability during molding.

4.Nuka〇Figure 1 is a cross-sectional view of a mold part in which metal silicone and reinforcing metal are glued with thermosetting resin to be fitted into the mold base.
FIG. 2 shows a cross-sectional view of the injection mold into which the mold parts are fitted.

1. Metallic silicon 2. Thermosetting resin adhesive 3, reinforcing metal member 4. Hole 5, sprue 6. Sprue lock pin 7, ejector pin 8. Ejector hole 9, return bin 10.
Guide pin 11, locating ring 12, molded product

Claims (1)

[Claims] 1. The outermost surfaces of the male and female molds (the surfaces that come into contact with the molding resin) constituting the cavity part of the injection mold have a purity of 99.9.
More than 99% of the material is made of silicon metal, which has been polished to an appropriate precision and is integrally bonded to metal reinforcements and adhesives. An injection mold is assembled by fitting this male or female mold into a mold. 2. The injection mold according to claim 1, wherein the adhesive between the metal silicone and the metal reinforcing material is a thermosetting resin. 3. The injection mold according to claim 1, wherein the adhesive between the metal silicon and the metal reinforcing material is cross-linked and cured by heat. 4. The first layer of the adhesive between the metal silicon and the metal reinforcing material is one that is cross-linked and cured by light at room temperature, and is further integrated with the reinforcing material using another adhesive. Injection mold as described in section. 5. The injection mold according to claim 1, wherein the adhesive between the metal silicon and the metal reinforcing material is crosslinked and cured at room temperature by a catalyst promoter. 6. The injection mold according to claim 1, wherein the adhesive thermosetting resin is made into a composite system by adding an inorganic filler, metal powder, or fibrous reinforcing material. 7. The adhesion surface of the metal silicon (the surface that adheres to the metal reinforcing material through the adhesive) and the adhesion surface of the metal reinforcement material are plated with metal or vapor-deposited with a metal suitable for adhesion to improve adhesive strength. An injection mold according to claim 1, which is integrally joined to a metal reinforcing material by a thermosetting resin. 8. The adhesive surface of metal silicon (the surface that is bonded to the metal reinforcing material via adhesive) is coated with a silane coupling agent, titanate coupling agent, or other organic coupling agent to improve adhesion with the thermosetting resin. The injection mold according to claim 1, which is integrally joined to a metal reinforcing material by a thermosetting resin with a primer coated thereon to improve adhesive strength.