JPS60159014A - Precision molded item - Google Patents

Abstract

PURPOSE:To secure transfer accuracy, hardness and adhesion, by applying a coating liquid mainly consisting of a monomer or oligomer capable of providing a polysiloxane type rigid coating, hardening the coating liquid, releasing the coating thereby forming a polysiloxane type rigid surface layer on a substrate. CONSTITUTION:A mold having a fine contoured pattern on the smooth surface is coated with a coating liquid mainly consisting of a monomer or oligomer capable of providing a polysiloxane type rigid skin, then if required, the liquid is preliminarily dried to form a film, and the film is heated to be hardened to give a polysiloxane type rigid surface layer (A). The thus obtained surface layer (A), after or before it is released from a mold, is bonded to a substrate (B) to provide a precision molded item. Thus, a precision molded item that is high in transfer accuracy, surface hardness, and adhesion to the vertically magnetized film and wherein the optical and magnetic properties of the vertically magnetized film would be less deteriorated can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a precision molded product having a smooth surface with a fine uneven pattern, such as an optical video disc or a digital audio disc.

(Background of the Invention) With the development of the information society, the demand for large-capacity information recording media has increased, and video discs, digital audio discs, etc. have been put into practical use.

Optical video discs have a smooth surface with depressions or island-like protrusions called pits arranged in a spiral pattern, and information is recorded based on the presence or absence of these pits and the focus length. One pit has minute dimensions, for example, 0.5 microns in diameter x 0.9 to 3 microns in length x 0.1 microns in depth or height, and the trunk spacing is also as small as 1.6 microns, for example. . Since optical video discs and digital audio discs having such fine patterns need to be supplied in large quantities at low cost, they are naturally molded from plastic and are now commercially available.

In addition, the magneto-optical disk is a PHMA disk with a thickness of 1.2 mm and a diameter of 180 mm, for example, which has spiral or concentric fine grooves for tracking (for example, 9.1 micron in diameter, 700 people in depth and 2.5 micron in pitch). A magnetic material such as T is deposited on a disk-shaped substrate by vacuum evaporation or sputtering.
This is a thin layer of amorphous perpendicular magnetization films such as bPe5GdTbPeSGdTbFeCo.

Press molding and injection molding have been employed or proposed to mold disks or disk-shaped substrates having such precise molding surfaces.

However, molded products obtained by either molding method have drawbacks such as poor transfer accuracy and the need for bulky equipment.

Therefore, the "indentation" or island-like protrusion that forms the bit,
Alternatively, a radiation-curable resin lacquer is applied onto a mold provided with protrusions forming spiral grooves, and then cured by irradiation with radiation, such as ultraviolet rays, electron beams, or gamma rays, to form the surface layer. A disk in which this was glued onto a plastic or other substrate was proposed (for example, in JP-A-58-108
042, 58-159202).

However, the acrylic resins and epoxy resins that have been proposed as radiation-curable resins have insufficient hardness and are easily scratched during handling, and these scratches can cause recorded information to not be reproduced correctly. It has been found.

Furthermore, the above-mentioned acrylic resins and epoxy resins had the disadvantage that the adhesion of the perpendicularly magnetized film was poor.

(Objective of the Invention) Therefore, the object of the present invention is a precision molded product having a fine uneven pattern on a smooth surface, such as an optical video disk or a digital audio disk, and the surface layer having the uneven pattern is high. It is an object of the present invention to provide a device having high transfer accuracy, high hardness, and high adhesion to a perpendicularly magnetized film.

Summary of Shinmei) Therefore, the present invention involves applying a coating or liquid mainly composed of a monomer or oligomer thereof that provides a polysiloxane hard coating onto a mold having a fine uneven pattern on a smooth surface. After curing, the mold is released to provide a precision molded product consisting of a polysiloxane hard surface layer (A) and a substrate (B).

The monomer that provides the polysiloxane hard coating used in the present invention has the general formula: % formula % (wherein R represents a hydrocarbon group having 1 to 3 carbon atoms with or without a substituent, R' represents a hydrocarbon group having 1 to 5 carbon atoms or an acyl group having 1 to 4 carbon atoms, and n is 0, ■ or 2.

Specific compounds included in the general formula include, for example, difunctional silane compounds such as dimethyldimethoxysilane, diethyldimethoxysilane, and dimethyldibutoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltributoxysilane, Ethyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, N-()rimethoxysilylprobyl)ethylenediamine, aminomethyltrimethoxysilane, 3-
Trifunctional silane compounds such as aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane,
Examples include tetrafunctional silane compounds such as tetramethoxysilicon, tetraethoxysilicon, tetrapropoxysilicon, and tetrabutoxysilicon.

These monomers may be made into oligomers in advance by partial hydrolytic condensation using acetic acid, hydrochloric acid, sulfuric acid, or the like.

As the solvent for dissolving the hexamer or its oligomer, alcohols, esters, ethers, ketones, halogenated hydrocarbons, aromatic hydrocarbons such as toluene, xylene, etc. are used.

A curing catalyst is generally added to the coating solution in addition to the above-mentioned hexamer or its oligomer and a solvent. As curing catalysts, saturated or unsaturated polycarboxylic acids or their acid anhydrides, polyvalent metals (e.g. Fe(I[l), Fe(II), A
It (I[[) , Ti (IV) , Co(I[
[), Cr(11[), Mn(II), V(III
), V (IV), Cn (II), Ca (II), M
g(II), Ni(I[), Zr(IV),)
Examples include alkoxides or chelate compounds, phenol compounds, metal nitrides such as dicyandiamide, and boron fluoride compounds. Incidentally, since the curing catalyst shortens the bot life of the coating solution, it is preferable to mix it immediately before coating.

Furthermore, the coating solution contains surfactants, viscosity modifiers, pigments, dyes,
Fillers and the like may also be added. Silica (colloidal silica) having an average particle size of 1 to 200 mm, particularly 10 to 30 mm, may be used as a filler.

The coating liquid thus prepared is applied to the surface of the mold, and the coating methods used include brush coating, spray coating, barcode coating, flow coating, dipping, roll coating, and spin coating.

After coating and forming a film by pre-drying if necessary, it is generally cured by heating at 50 to 250°C to obtain a polysiloxane hard surface layer (A). The thickness of such surface layer (A) depends on the application, but generally 1 to 100 microns is sufficient. - Repeat several times if the desired film thickness is not obtained after the first coating.

The surface layer (A) thus obtained is adhered to the substrate (B) after or before being released from the mold to obtain the precision molded product of the present invention. The substrate (B) may be made of plastic, metal, ceramic, glass, etc. depending on the purpose. Of course, it is also possible to adhere the surface layer (A) to both the front and back surfaces of the substrate (B). In order to adhere the surface layer (A) to the substrate (, B), an adhesive may be used or heat fusion may be performed as the case requires. As the adhesive, epoxy, urethane, acrylic, silicone, etc. are used, depending on the type of substrate.

The precision molded product of the present invention can be used for optical video discs and digital audio discs, substrates for magneto-optical discs, phase-type Fresnel zone plate lenses, etc. depending on the uneven pattern.
Used for diffraction gratings, etc.

The present invention will be specifically explained below using Examples.

(Example) A nickel mold made from a glass master by electroforming is prepared.

This mold is a circular plate with a diameter of 180++ u++ and a thickness of 10 mm (including the pedestal).As shown in Figure 1, the mold is a circular plate with a diameter of 180++ u++ and a thickness of 10 mm (including the pedestal). The stripes are formed in a spiral shape. Commercially available NIKC manufactured by Katsuta Kako Co., Ltd.
After mixing 100 parts by weight of the main agent ^-430 of O^T (trade name) and 7 parts by weight of catalyst Z-102, the mixed liquid was applied to the surface of the mold described above using a spin cord method (rotation speed 10,100 or
After coating with p and air drying at room temperature for 30 minutes,
It was baked at 80° C. for 1 hour and then further baked at 100° C. for 1 hour to harden it.

The obtained polysiloxane hard coating 111 with a film thickness of 10μ
Peel off (A) from the mold and make it with a diameter of 180n++*
This was attached to a hard acrylic resin substrate (B) with a thickness of 1 to 2 mm using an epoxy adhesive to prepare a magneto-optical disk substrate.

The surface of this substrate has a pencil hardness of 6H, which is much harder than conventional acrylic resin or epoxy resin surface layers.

Further, a TbFe-based magnetic alloy perpendicularly magnetized film with a thickness of 500 mm was formed on the magneto-optical disk substrate of this example by vacuum evaporation, but the adhesion of the magnetized film to the substrate was sufficient.
Furthermore, the deterioration of the magneto-optical properties of the perpendicularly magnetized film was less than that of the plastic molded substrate.

(Effects of the Invention) According to the present invention, a precision molded product can be obtained that has high transfer accuracy, high surface hardness, and high adhesion to the perpendicularly magnetized film, and has little deterioration in the magneto-optical properties of the perpendicularly magnetized film.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of a mold used in an example of the present invention. Applicant: Nippon Kogaku Kogyo Co., Ltd. Agent: Takashi Watanabe

Claims (1)

[Claims] 1. On a mold having a fine uneven pattern on a smooth surface,
A polysiloxane-based hard surface layer (A
) and a substrate (B). 2. The monomer has the general formula: % formula %) (wherein R represents a hydrocarbon group having 1 to 3 carbon atoms with or without a substituent, and R' is a hydrocarbon group having 1 to 5 carbon atoms) or an acyl group having 1 to 4 carbon atoms, and n is 0.1 or 2.) The precision molded article according to claim 1, wherein the precision molded article is an organosilicon compound represented by the following formula.