JP2002264140A - Resin mold manufacturing method and resin molded article molded using resin mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin mold manufacturing method capable of obtaining a large number of resin molds from one expensive metal mold and capable of reducing the manufacturing cost of the metal mold, and also to provide a resin molded article molded using each of the resin molds. SOLUTION: The resin mold manufacturing method consists of a process for manufacturing an intermediate mold comprising a first thermosetting resin such as an addition type silicon resin or the like on the uneven surface of the flat plate metal mold having unevenness of a predetermined shape, and a process for performing the primary curing and secondary curing of the resin mold comprising a second thermosetting resin such as a thermosetting epoxy resin or the like, successively using the intermediate mold to manufacture the perfectly cured resin mold. The resin mold is extended or contracted within a range of 0.6-1.00% to have a different dimension from the dimension of the metal mold.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a resin mold and a resin molded article molded using the resin mold. In particular, the resin molded article is used for a projection type television screen. The present invention relates to a resin molded product such as a Fresnel lens plate, a lenticular plate, or an optical component such as an overhead projector (OHP).

[0002]

2. Description of the Related Art Heretofore, the following is known as a typical method of using a double plate in molding such a lens sheet.

Pressing method A thermoplastic resin is pressed using a heated stamper.
A method of molding the lens surface.

Casting method A method in which a melt-softened thermoplastic resin is applied or injected onto a surface of a stamper where irregularities are formed, and the resin is solidified to form a lens surface.

In recent years, instead of such a thermoplastic resin, a lens sheet is formed by using a resin that is cured by irradiation with ionizing radiation typified by ultraviolet (UV) or electron beam (EB). As a technique, there is a technique exemplified below.

[0006] Japanese Patent Application Laid-Open No. 61-177215 discloses an ultraviolet ray in a gap defined by a transparent resin plate that transmits ultraviolet rays and a concave / convex forming surface of a stamper on which concaves and convexes (Fresnel lens surface) of a predetermined shape constituting a lens are formed. A method for producing a laminated Fresnel lens by filling a curable resin, irradiating the resin with ultraviolet rays from the transparent resin plate side to cure the resin, and polymerizing and bonding the resin to the transparent resin plate.

Patent No. 2790181, Patent No. 260
No. 8440 An ultraviolet-curable resin liquid is applied to one side edge of the lens mold so as to form a liquid pool, and a transparent resin film is coated thereon. How to spread the resin. A method of forming an intermediate mold (resin) on a metal mold, and molding the resin using the resin mold formed on the intermediate mold.
and so on.

[0008] The above proposals have been made to solve the problem of air bubble mixing, and are intended to produce a lens sheet having excellent performance without bubbles while using a transparent resin film while utilizing this flexibility. It is. In the above method, many dies must be cut in order to perform mass production, so that much time and cost are required. Another method is that in the method of Japanese Patent No. 2610029, the master mold and the resin mold have the same dimensions.
In -141663, the curing temperature of the intermediate mold and the resin is set so that the dimensional ratio between the master mold and the resin mold is 1.01 to 1.05 or 0.80 to 0.99. However, in actual production, it is desired to quickly produce a resin mold that can stably mold a lens sheet having a desired size. Even if the mold and resin mold have different dimensional ratios, based on the knowledge that a certain dimensional ratio can be obtained under certain curing conditions, determine the dimensions of the master mold, cut the mold shape, and As a result, a desired size of the resin mold may be obtained. Therefore, there is no need to make the dimensions of the master mold and the resin mold greatly different from those of JP-A-9-141663.

[0009]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a large number of resin molds can be obtained from one expensive metal mold. It is an object of the present invention to provide a method for manufacturing a resin mold and a resin molded product molded using the resin mold, which can be reduced.

[0010]

Means for Solving the Problems In order to solve the above problems, the invention according to claim 1 uses a mold having a predetermined shape surface to cure a cured product of an ultraviolet curable resin or an electron beam curable resin. In a resin mold used for manufacturing a resin molded product, a first thermosetting resin such as an additional type silicone resin is applied or formed on the uneven surface of a flat metal mold having unevenness of a predetermined shape by forming or casting. Defoaming, heat-curing, demolding, producing a first thermosetting resin mold (intermediate mold); and a second thermosetting resin such as thermosetting epoxy resin as the intermediate mold. A step of applying a resin, rolling and forming, first hardening by heating, and demolding; and a second hardening at a temperature higher than a heating temperature of the first hardening to completely harden the resin mold. The resin mold is adapted to the dimensions of the metal mold. A method for producing a resin-type to characterized by having different dimensions extend in the range of 0.6% to 1.00%.

According to a second aspect of the present invention, there is provided a molding die used for manufacturing a resin molded product made of a cured product of an ultraviolet curable resin or an electron beam curable resin using a mold having a predetermined shape surface. A first thermosetting resin such as an additional silicon resin is applied or formed on the uneven surface of the flat metal mold having a shape having irregularities, or is formed by casting, vacuum degassing, heat curing, and demolding. A step of producing the first thermosetting resin mold (intermediate mold), and applying a second thermosetting resin such as a thermosetting epoxy resin to the intermediate mold, rolling and forming, and primary curing by heating And a step of removing the mold, and a step of performing a secondary curing at a temperature higher than the heating temperature of the primary curing to completely cure the resin mold. 0.6% to 1.00% of the mold size
The method for manufacturing a resin mold is characterized in that the resin mold has different dimensions by reducing in the range of

The invention according to claim 3 is the invention according to claim 1 or 2
The method for producing a resin mold according to the above, wherein an antistatic material is mixed in the resin mold.

According to a fourth aspect of the present invention, in the method of manufacturing a resin mold according to any one of the first to third aspects, the uneven shape is any one of a Fresnel lens, a lenticular lens, and a prism lens. A method for manufacturing a resin mold, characterized in that:

According to a fifth aspect of the present invention, there is provided a resin molded product formed by using the resin mold according to the first to fourth aspects.

<Operation> By using a resin mold, the cost of the mold can be reduced as compared with the direct mold method such as Japanese Patent No. 2790181 and Japanese Patent No. 2608440. , Compared to the resin mold manufactured by the method of Japanese Patent No.
A resin mold for obtaining desired dimensions can be stably manufactured in a short time.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for producing a resin mold according to the present invention will be described in detail. Since the stamper having the irregularities of a predetermined shape is cut on a flat surface using a vertical lathe,
It takes 4 days for a 0 inch size and 5 days for a 50 inch size. Further, there is a high possibility that the mold may be damaged due to scratches or the like in the molding process.

Therefore, the method of manufacturing a resin mold according to the present invention uses a mold having a predetermined shape surface to form a molding used for manufacturing a resin molded product made of a cured product of an ultraviolet curable resin or an electron beam curable resin. In the mold, a first thermosetting resin such as an additional type silicone resin is applied or formed on the uneven surface of the flat metal mold having unevenness of a predetermined shape by application or casting, vacuum degassing, and heat curing, Removing the mold and preparing the first thermosetting resin mold (intermediate mold); applying a second thermosetting resin such as a thermosetting epoxy resin to the intermediate mold; A step of primary curing and demolding by
Performing a second curing at a temperature higher than the heating temperature of the next curing, and completely curing the resin mold to produce a second thermosetting resin mold, wherein the first heat By controlling the temperature at which the curable resin mold is cured and the temperature at which the second thermosetting resin mold is cured, the resin mold can be 0.6% to 1.00% of the size of the metal mold. A resin mold characterized by extending in a range and having different dimensions, or a resin mold characterized by contracting in a range of 0.6% to 1.00% and having different dimensions. is there.

The curing temperature T1 of the first thermosetting resin and the second
When the primary curing temperature T2 of the thermosetting resin and the secondary curing temperature T3 of the second curable resin are set to produce a stable resin mold as soon as possible, However, in the method of manufacturing the resin mold, the dimensions are often not the same as the dimensions of the mold due to material restrictions. Therefore, it is not always possible to make the master mold and the resin mold have the same dimensions as in the method of Japanese Patent No. 2610029. Accordingly, an object of the present invention is to provide a method for stably forming a resin mold even if the resin mold does not have the same dimensions as the mold.

When the factors and conditions for manufacturing the resin mold are determined by the symbols shown in Table 1, the dimensions of the resin mold are set to LJ.
Is a dimensional change represented by the following equation. LJ = LK × {1+ (T1-T0) K1} * (1-S
1) * ｛1+ (T0−T1) K2｝｝ * ｛1+ (T2-
T0) K2｝｝ * (1-S2) * ｛1+ (T0-T2)
K3｝｝ * (1-S3) The curing temperature T1 of the first intermediate mold, the primary curing temperature T2 of the molded resin mold, and the secondary curing temperature T3 of the molded resin mold are set. A resin mold that is stretched or reduced by 0.6% to 1.00% is manufactured. Where LJ / LK
That is, {1+ (T1-T0) K1} * (1-S1) * {1+
(T0-T1) K2｝｝ * ｛1+ (T2-T0) K
2 {* (1-S2) * {1+ (T0-T2) K3}
* (1-S3) will be referred to as a dimensional ratio.

[0020]

[Table 1]

In general, the characteristics required of the resin mold are that the mold is excellent in transferability from the mold, there is no deterioration of the mold, and the mold can be used repeatedly. Next, when a UV-curable resin (hereinafter, referred to as UV resin) or an electron beam-curable resin (hereinafter, referred to as EB resin) and the like are applied, they can be uniformly applied without being repelled, and are cured when irradiated with UV or EB. It is required that the releasability from the material be smooth.

<Silicon Resin Type (Intermediate Type)> When the silicon used has a fine shape, an additional type is desirable. The condensation type does not reproduce the shape with a fine shape. After a predetermined amount of the main component of silicon and the curing agent are mixed, vacuum degassing is performed, and then vacuum injection is performed into a metal mold, and a curing temperature T1 ° C. for a certain period of time.
Cured, demolded and formed.

<Epoxy Resin Type> In general, an epoxy resin is used, but in the present invention, there is no particular limitation as long as it is liquid at normal temperature. Due to the nature of the vacuum casting, 1000-3000 mPa. s. After solidifying at T2 ° C. for a certain period of time, the silicon mold is peeled off, and further solidifying at T3 ° C. for a certain period of time. Thereby, corrosion by the monomers of the UV and EB resins is less likely to occur, and the durability of the epoxy mold is improved. Other materials include a urethane resin, a phenol resin, a melamine resin, an unsaturated polyester, a polyimide bismaleid triazine resin, a polycisalane, and the like.

<Radiation-Curable Resin> The resin molded product of the present invention is made of a radiation-curable resin, and there are various radiation-curable resins.
A UV-curable resin having an acryloyl group in the molecule. It is an epoxy acrylate, urethane acrylate, polyester acrylate, or polyol acrylate oligomer, polymer and monofunctional, bifunctional, or polyfunctional polymerizable (meth) acrylic. Monomers such as tetrahydrofurfuryl acrylate, 2-hydroxyethyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate,
A mixture of monomers, oligomers, polymers and the like such as trimethylolpropane triacrylate, pentaerythritol triacrylate, and pentaerythritol tetraacrylate is used.

[0025] Photopolymerization initiators such as benzophenone, diethylthioxanthone, benzyldimethylketal, 2-hydroxy-2-methyl-1-phenylpropan-1-one,
There are 1-hydroxycyclohexylphenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1, acylphosphine oxide, etc., but the photopolymerization initiator does not always react 100%. Since the unreacted one adversely affects the performance of the molded lens, it is added in the range of 0.1 to 7% by weight, preferably 0.5 to 5% by weight, so that no uncured portion remains. You should stop the quantity.

In some cases, a diluent may be used, and organic solvents such as acetone, ethanol, methanol, ethyl acetate, chloroform, carbon tetrachloride, tetrahydrofuran, cyclohexane, diethyl ether, methyl ethyl ketone, toluene, benzene, etc. Is used.

Examples of the diffusing agent include, for example, glass beads, silica, inorganic oxides, inorganic carbonates, inorganic sulfates, and organic resin beads. May be used.

Other additives include an ultraviolet absorber, a light stabilizer, a surfactant, an antifoaming agent, an antistatic agent, an antioxidant, and a flame retardant. These additives are formed by molding. The amount of the additive must not adversely affect the performance of the lens, or the amount of addition should not adversely affect the performance of the lens.

<Transparent film> As a substrate for forming the resin molded product of the present invention, a transparent film that transmits radiation is used. The transparent film is an embossable stamper and a material that can be wound up, specifically, a polyester resin, a polyolefin resin, a polystyrene resin,
A film-like material such as a methacrylic resin, a polycarbonate resin, a synthetic resin such as a vinyl chloride resin or a composite thereof is used.

In the present invention, among others, polyethylene terephthalate (PET), polyvinyl chloride (PV)
C), polycarbonate (PC), polymethyl methacrylate (PMMA), methacryl styrene (MS) and the like are preferable.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, as one embodiment of the present invention, a method of manufacturing a resin mold for molding a Fresnel lens and a resin molded product of Fresnel lens molded using the resin mold will be described.

FIG. 1 is an explanatory view showing, as an example, a method for producing a resin mold for molding the Fresnel lens of the present invention and a method for molding a resin molded lens product using the resin mold. (1) Fresnel metal mold A brass plate is mounted on a vertical lathe, flattened and cut, and then the inverted mold of the Fresnel lens is spirally cut. This takes about 5 days with a size of about 50 inches. Next, after the cutting is completed, chrome plating is performed to perform a surface protection treatment.

(2) Silicon type (intermediate type) The main agent and the curing agent are prepared using Shin-Etsu Chemical or additional silicon of Toshiba silicon resin, and vacuum degassing is performed. This is vacuum-poured into the upper end of a 50-inch metal mold by about 40 kg. In the case of the silicon shown below, it hardens sufficiently at 50 ° C. in about 2 hours. If it is at room temperature, it must be left for one day. Here, curing is performed at 20 ° C. for 24 hours. After curing, the silicon mold (intermediate mold) is peeled from the mold. If the temperature is higher than room temperature, it can be cured quickly.

(3) Epoxy Resin Type A main component of a liquid epoxy resin at room temperature and a curing agent are prepared, and vacuum degassing is performed. 30 kg of the mixed epoxy resin is vacuum-injected into a silicon mold. In this state, heat curing is performed at 60 ° C. for 5 hours. Next, the silicon matrix was peeled off, and a further 20
React completely at 0 ° C. for 10 hours. The epoxies shown below typically require about 5 hours at 60 ° C and 10 hours at 200 ° C. If the curing temperature is higher than usual, curing can be performed quickly. As a result, even in the molding at the level of several hundred times, it can withstand corrosion caused by the monomers of the UV and EB resins.

Table 2 shows the physical properties of the materials used in the examples of the present invention.

[0036]

[Table 2]

With T1 and T2 larger than usual, a resin mold can be manufactured although the dimensional ratio is not 1. 1) For example, as shown in FIG. 2, when the primary curing temperature of the molded resin mold is fixed (T2 = 60 ° C.), and the curing temperature T1 of the silicone resin mold (intermediate mold) is changed from 55 ° C. to 75 ° C. As shown in the table below, a resin mold having a dimensional ratio of 0.994 to 0.99 can be manufactured. In this case, curing usually takes 24 hours at room temperature, but can be completed within 2 hours.

2) For example, as shown in FIG. 3, when the curing temperature of the intermediate mold is fixed (T1 = 35 ° C.) and the primary curing temperature T2 of the molded resin mold is changed from 125 ° C. to 170 ° C. As shown below, a resin mold having a dimensional ratio of 1.006 to 1.01 can be produced. In the case of this primary curing, curing usually takes 5 hours but can be completed within 2 hours.

(4) Fresnel lens material Substrate: polycarbonate resin (1 mm thick), plate-like material. UV resin: Composition of reactive prepolymer (ultraviolet curable resin) Urethane acrylate oligomer (NK-oligo U
-4HA 47% by weight of Shin-Nakamura Chemical Co., Ltd., 30% by weight of 2-hydroxy-3-phenoxypropyl acrylate (Aronix M-5700 manufactured by Toagosei), and 20% by weight of tetrahydrofurfuryl acrylate (Biscoat # 150 manufactured by Osaka Organic Chemicals) % And 1% by weight of 1-hydroxycyclohexyl phenyl ketone (Irgacure 184, manufactured by Nippon Ciba Geigy).

As an example, a method of molding a Fresnel lens using the resin mold of the present invention will be described with reference to FIGS.
Description will be made based on (g). A UV resin 8 is applied to the center of the epoxy resin mold 7 on which the pattern has been cut to form a resin pool. A plastic plate 9 is placed thereon, and pressed from above the plastic plate by press machines 10 and 10 '.
The V resin is formed while being spread in the circumferential direction. After stopping the press, UV light source 11 was placed on the plastic plate.
After exposing to UV light to cure the resin, it is peeled off to complete the Fresnel lens sheet 12.

The configuration is not limited to the above embodiment, and the configuration may be changed without departing from the spirit of the present invention. For example, instead of a prism lens sheet, a lenticular sheet or a Fresnel lens sheet may be manufactured, or a resin molded product having an irregular shape other than the lens sheet may be manufactured.

[0042]

According to the present invention, many resin molds can be manufactured from one expensive metal mold. In addition, the number of times the metal mold is cut can be reduced, and the cost of preparing the metal mold tree can be significantly reduced. Therefore, by using the resin mold, the manufacturing cost can be reduced, and inexpensive resin molded products such as lenticular lens sheets and Fresnel lens sheets used for projection televisions and the like can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a method for producing a resin mold and a method for molding a resin molded article molded using the resin mold as one embodiment of the present invention. (A) is a metal mold, (b) is a step of producing a silicone resin mold (intermediate mold), (c) is
Step of producing an epoxy resin type (resin type), (d)
Epoxy resin mold (resin mold), (e) to (g) are steps of molding a Fresnel lens sheet using a resin mold, (h)
Is the step of removing the Fresnel lens sheet from the resin mold,
(I) is a Fresnel lens sheet.

FIG. 2 is a diagram showing a relationship between a curing temperature of an intermediate mold and a dimensional ratio of a resin mold to a metal mold in one embodiment of the method for manufacturing a resin mold of the present invention.

FIG. 3 is a diagram showing the relationship between the primary curing temperature of the resin mold and the dimensional ratio of the resin mold to the metal mold in one embodiment of the method for manufacturing the resin mold of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Metal mold 1a ... Concavo-convex shape 2 ... Silicon resin 3, 6 ... Aluminum plate (backing plate) 4 ... Silicon resin mold 5 ... Epoxy resin 7 ... Epoxy resin Mold 8: UV resin 8A: Cured 9: Plastic plate 10, 10 ': Press machine 11: UV light source 12: Fresnel lens sheet

Claims (5)

[Claims] 1. A molding die used for manufacturing a resin molded product made of a cured product of an ultraviolet curable resin or an electron beam curable resin using a mold having a predetermined shape surface, wherein a flat plate having irregularities of a predetermined shape. A first thermosetting resin such as an additional silicon resin is applied or formed on the uneven surface of the metal mold, vacuum degassed, heated and cured, demolded, and then subjected to the first thermosetting. Step of preparing a conductive resin mold (intermediate mold), applying a second thermosetting resin such as a thermosetting epoxy resin to the intermediate mold, rolling and molding, primary curing by heating, and demolding A step of performing a secondary curing at a temperature higher than the heating temperature of the primary curing, and completely curing the resin mold, wherein the resin mold has a size corresponding to the dimension of the metal mold. Stretched in the range of 0.6% to 1.00% and have different dimensions A method for producing a resin mold, comprising: 2. A molding die used for manufacturing a resin molded product made of a cured product of an ultraviolet curable resin or an electron beam curable resin using a mold having a predetermined shape surface, wherein a flat plate having irregularities of a predetermined shape. A first thermosetting resin such as an additional silicon resin is applied or formed on the uneven surface of the metal mold, vacuum degassed, heated and cured, demolded, and then subjected to the first thermosetting. Step of preparing a conductive resin mold (intermediate mold), applying a second thermosetting resin such as a thermosetting epoxy resin to the intermediate mold, rolling and molding, primary curing by heating, and demolding A step of performing a secondary curing at a temperature higher than the heating temperature of the primary curing, and completely curing the resin mold, wherein the resin mold has a size corresponding to the dimension of the metal mold. Have different dimensions, reduced in the range of 0.6% to 1.00% A method for producing a resin mold, comprising: 3. The method for manufacturing a resin mold according to claim 1, wherein an antistatic material is mixed in the resin mold. 4. The method for manufacturing a resin mold according to claim 1, wherein the uneven shape is any one of a Fresnel lens, a lenticular lens, and a prism lens. Manufacturing method of resin mold. 5. A resin molded article formed by using the resin mold according to claim 1.