JPS63149116A - Manufacture of cast-molded product - Google Patents

Abstract

PURPOSE:To obtain a cast-molded product which is superior in mold release properties and continuity, favorable in dimensional accuracy and superior in optical characteristics, by making use of a mold surface-treated with a surface treatment agent containing fluoroalkyl silane. CONSTITUTION:An organic silane compound possessing two or more methoxyl groups and/or ethoxyl groups bound with a silicone atom and at least a fluoroalkyl group bound with the silicone atom possessing three or more fluorine atoms is preferable as fluoroalkyl silane. A surface treatment agent containing fluoroalkyl silane as an indispensable ingredient is dissolved into a solvent and used as a dilute solution of the surface treatment agent. It is good to cure setting type liquid resin for cast molding on the surface of the mold to which surface treatment has been applied to obtain a cast-molded product. In the case where a cast-molded material is laminated by making a thermoplastic resin sheet a base, active energy ray setting type liquid resin, which can be cured without caring about a deformation, is used after preparation of the setting type liquid resin.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is particularly applicable to a molded product that can easily obtain a molded product having excellent optical properties without any shape defects even if it has a complex shape, and without an oil film on the surface. The present invention relates to a method of manufacturing a cast molded product suitable for manufacturing optical precision molded products such as optical discs.

(Prior Art) In recent years, with the development of optronics and mechatronics, the need for optical precision molded products having complex and fine shapes on a base material has increased. A typical example of this is the original disk, which is a promising optical storage medium. An optical disk requires a transparent substrate having unevenness on its surface with a height of about 1 μm and a width of about 5 μm in order to guide the laser beam of the laser pickup. Currently, the mainstream manufacturing method for this board is injection molding of transparent resins such as polycarbonate and polymethyl methacrylate. There is a drawback that birefringence increases due to the orientation of the laser beam, which tends to impede signal reading by laser light. In addition, the viscosity of the molten resin is high and it is difficult to fill the molten resin into a mold with a fine shape without voids, which tends to cause shape defects.Moreover, a large molding machine that uses high temperatures is used, so the molded product
There is also the drawback that the energy cost of individual roars is high.

In order to improve these drawbacks, a cast molding method has been developed in which UV-curable liquid resin is filled between a shaped metal mold and a transparent plastic base material, and then cured to transfer the shape of the mold onto the base material. It has been devised.

(Problems to be Solved by the Invention) The liquid resin used in the molding method must be able to quickly fill the gap between the base material and the mold, and must have a low viscosity.

In addition, there is no significant difference in the critical surface tension between the base material and the mold surface.
Since the liquid resin wets both surfaces well, the same adhesion force is generated, and especially when the shape given to the mold surface is complex, peeling may occur at the interface between the base material and the cured product of the liquid resin during mold release. There are disadvantages such as defects in shape and defects in shape. One way to improve the mold release property is to apply a Cynocone or Teflon mold release agent to the surface of the mold. Remains as a different oil film layer, causing problems in optical properties,
The drawback is that the mold release effect lasts only a few times and productivity is poor.

(Means for Solving the Problems) In view of the above-mentioned circumstances, the inventor conducted intensive research and found that by using a mold having a hardened coating of fluoroalkylsilane, a cast-molded product without the above-mentioned drawbacks could be obtained. The present inventors have discovered that a long-lasting mold release effect can be obtained, and have completed the present invention.

That is, the present invention provides a method for manufacturing a cast molded article, which is characterized by using a mold whose surface has been treated with a surface treatment agent containing fluoroalkylsilane.

Examples of the fluoroalkylsilane used in the present invention include organic silane compounds having at least one alkoxy group bonded to a silicon atom and at least one fluoroalkyl group bonded to a silicon atom in the molecule. and/or ethoxy group and at least one fluoroalkyl group bonded to a silicon atom having three or more fluorine atoms. 2S t C0Ckl;)5゜CF
! , CH2CH25i (OC2Hs) 3. C.F.
3 (CF 2 ) 5CH2CH2S l (OCH
3) 3゜CF 5 (CF2) 5CH2CH2S
i (OC2Hs)5, CF3 (CF2)
7CH2Q(2S i (OCH3)3.

0F3(CF2)7CH2CH2Sl(CHρ(OCH
3) There is a second prize.

The surface treatment agent containing fluoroalkylsilane used in the present invention is one that contains the above-mentioned fluoroalkylsilane as an essential component and further contains other organic silane compounds, catalysts, additives, etc. as necessary. It is usually dissolved in a solvent such as methanol, ethanol, inglobil alcohol, or water and used as a dilute solution of a surface treatment agent.

In addition, as the above-mentioned surface treatment agent, one having a critical surface tension of 13 to 30 dyn/crn after curing is usually used.
Among these, the critical surface tension after curing is small and the mold releasability is excellent, and the difference in surface tension from the surface tension of the curable liquid resin for cast molding is not too large and the wettability is good. Critical surface tension after curing is 15 to 23 dyn/c1 in that it can prevent air bubbles from being entrained due to poor wettability during preparation.
n is preferred, especially 17-18 dyn/crn
Even if the mold has a particularly complicated shape, it is preferable because it has excellent mold releasability and does not entrain air bubbles during preparation. Therefore, the surface treatment agent is a combination of two or more fluoroalkylsilanes.
The critical surface tension after curing may be adjusted by adding other organic silane compounds, such as alkylsilanes, to the fluoroalkylsilane having 11 or more types of fIC.

The concentration of the organic silane compound containing fluoroalkylsilane as an essential component contained in the diluted solution of the surface treatment agent is usually 0.01 to 5M because it is necessary to form a hardened thin film of the surface treatment agent on the mold surface. h, preferably 0.1 to 2
% by weight.

Furthermore, a catalyst such as acetic acid may be added to the surface treatment agent in order to improve the curing speed of the fluoroalkylsilane. Preferably.

The resin used in the cast molding of the present invention is not particularly limited as long as it is a curable liquid resin, and general resins that change from a liquid to a solid by heat, moisture, oxygen, active energy rays, etc. Any of these can be used, including acrylic resins, epoxy resins, urethane resins, polyester resins, etc., and if necessary, thermal polymerization initiators, photopolymerization initiators, photosensitizers, and other additives. , a liquid resin containing a solvent and the like.

In particular, it contains one or more compounds selected from polyester (meth)acrylate, polyurethane (meth)acrylate, epoxy (meth)acrylate, polyol (meth)ac')V-), (meth)acrylic monomer, vinyl monomer, etc. A solvent-free acrylic active energy ray-curable liquid resin is preferable because it does not require solvent removal, has a fast curing speed, and can be cured at low temperatures, so there are no problems such as deformation of the base material. In particular, 20 to 70% by weight of an acrylic ester having at least one hydroxyl group and one acryloyl group in the molecule, and 25 to 75% by weight of an acrylic ester having a molecular weight of 130 to 1,000 and having two acryloyl groups in the molecule. Weight% and acrylic monomer having 3 or more acryloyl groups in the molecule 5 to 5
Solvent-free acrylic ester resin containing 0% by weight has a low viscosity and is easy to handle, and has a good balance between rigidity and flexibility to withstand stress concentration during curing and shrinkage. This is preferred because a bonded product with excellent adhesiveness, strength, and rigidity can be obtained.

Next, as the cast molding mold used in the present invention, one having an inorganic material such as metal, ceramic, or glass on the surface is suitable.In particular, metal has excellent workability for forming complex shapes. This is the most preferable option.

In this case, the metal surface is treated with acid, flame, or
Treating the mold with plasma, ionic particles, etc. to form an oxidized surface improves the adhesion with the cured fluoroalkylsilane film.The preferred method for surface treatment of the mold is to apply a hardened alkylfluorosilane to the surface of the mold. Any method may be used as long as the film is laminated, and there are no particular limitations. For example, after laminating the surface treatment agent on the mold surface using a dipping method, a spraying method, etc., the solvent is dried and removed, and then the treatment is carried out at 100 to 160°C. A method of heating and curing for 0.5 to 3 hours may be mentioned.

In order to obtain a cast molded product by the method of the present invention, a curable liquid resin for cast molding is applied, for example, by injection, press fitting, or coating, onto the surface of the mold that has been surface-treated as described above. It may be prepared by a method such as the above, and then allowed to harden. The curable liquid resin may be cured by heat, moisture, active energy rays, etc., but in the case of using a thermoplastic resin plate as a base material and laminating a cast molded product on top of it, the substrate and mold It is preferable to use an active energy ray-curable liquid resin because it can be cured at room temperature without necessarily being deformed by heating after the curable liquid resin is charged during the process, and the curing speed is fast.

(Effects of the Invention) In the method for producing a cast molded product of the present invention, the thickness of fluoroalkylsilane firmly adhered to the surface of the mold by surface treatment is usually 1 μm or less, but can be increased to 0.1 μm if necessary. Because the hardened thin group (product) Wt is low, cast-molded products with excellent mold releasability and durability, good dimensional accuracy, and excellent optical properties without shape defects or adhesion of oil films with different optical properties can be obtained. It has the advantage of being able to

(Example) The present invention will be specifically described below with reference to Examples and Comparative Examples. All parts and parts in the examples are based on weight.

Examples 1-3 Table 1 was prepared in methanol by adding acetic acid and adjusting the voice to 4.
The fluoroalkylsilane shown in 1 was added to a surface treatment agent adjusted so that the concentration after addition was 1% in Examples 1 and 2, and 1.5% in Example 3. A nickel-plated brass mold having parallel grooves with a width of 50 μm, a depth of 10 μm, and an interval of 50 μm was immersed on the surface of a .2 wm cavity for 30 minutes, and then hardened at 140°C for 1 hour. A surface-treated mold having a cured film of fluoroalkylsilane (thickness of 1 μm or less) on the surface was obtained.

Next, the width is 15 m, the height is 15 m, the thickness is 1.2 m, and the bottom surface (joint surface with the cast molding resin) is 15 + + + m x 15 m.
An ultraviolet curable liquid resin consisting of 70 parts of acrylic monomer and 0.5 parts of 1-hydroxycyclohexyl phenyl ketone that hardens on the bottom surface of an L-shaped methyl methacrylate resin plate [hereinafter referred to as UV curable acrylic resin (2)] and 400 mJ/c of ultraviolet light using a high-pressure mercury lamp.
After curing the acrylic resin flash by irradiating it for 12 seconds at an intensity of 2 m, one end of the L-shaped methyl methacrylate resin plate was pulled at a speed of 1.0wn10 using a tensile tester to obtain the L-shaped resin plate. The cast molded product bonded to the bottom of the mold was released from the mold. Next, the same cast molding was repeated to obtain 15 cast molded products, and the presence or absence of an oil film on the surface of the first cast molded product was evaluated.
The presence or absence of shape defects in the cast molded product was visually evaluated, and the maximum load during the first and 15th mold release was measured as the mold release strength. The results are shown in Table-1.

Example 4 A brass mold that was the same as that used in Example 1 except that it did not have nickel plating was immersed in concentrated nitric acid at room temperature for 5 seconds, thoroughly washed with pure water, dried at room temperature, and the surface A mold was obtained which was oxidized, and then this mold was used to form a mold on the bottom surface of an L-shaped resin plate in the same manner as in Example 1 except that the concentration of fluoroalkylsilane in the surface treatment agent was changed to 0.5%. A bonded cast molded product was obtained, and the presence or absence of an oil film, the presence or absence of shape defects, and the mold release strength were measured in the same manner.

The results are shown in Table-1.

Example 5 Instead of the L-shaped methyl methacrylate plate with a thickness of 1.2 cm, an L-shaped lath plate with a thickness of 1.5 w was used, and a U-shaped lath plate was used.
V-curing acrylic resin (Evicron 830 in place of *)
[Bisphenol F type epoxy resin manufactured by Dainippon Ink & Chemicals, epoxy drawing weight 165-185, viscosity 3,000
~4,000 cps] 100 copies and Ebicure 4
04 [Amine curing agent manufactured by Shell Chemical ■] Thermosetting liquid resin consisting of 50 parts [hereinafter referred to as thermosetting epoxy resin (Y)
A cast-molded product bonded to the bottom of an L-shaped glass plate was obtained in the same manner as in Example 1, except that the resin was heat-cured for 30 minutes at 50°C (instead of ultraviolet curing). The presence or absence of an oil film, the presence or absence of shape defects, and the mold release strength were measured. The results are shown in Table-1.

In Comparative Example 1, instead of a surface-treated mold having a hardened coating of fluoroalkylsilane on the surface, Lublon LA
[Non-curing fluorocarbon resin mold release agent manufactured by Daikin Industries, Ltd.]
In addition, in Comparative Example 2, TSM 6822 [Toshiba Silicone ■
A cast mold bonded to the bottom surface of an L-shaped resin plate was prepared in the same manner as in Example 1, except that a mold formed by uniformly applying a non-curing silicone resin mold release agent] by a spray method was used. A molded article was obtained, and then the presence or absence of an oil film and the presence or absence of shape defects were evaluated and the mold release strength was measured in the same manner. The results are shown in Table-1.

Comparative Example 3 L
A cast molded product bonded to the bottom surface of a letter-shaped resin plate was obtained, and then the presence or absence of an oil film, the presence or absence of shape defects, and the mold release strength were measured in the same manner. The results are shown in Table-1.

Comparative Example 4 L
A cast molded product bonded to the bottom surface of a letter-shaped resin plate was obtained, and then the presence or absence of an oil film, the presence or absence of shape defects, and the mold release strength were measured in the same manner. The results are shown in Table 1.

Claims (1)

[Claims] A method for producing a cast molded product, comprising using a mold whose surface has been treated with a surface treatment agent containing fluoroalkylsilane.