JP3928422B2 - Resin mold and method for producing the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a mold used for producing optical components such as a screen of a projection television and a Fresnel lens sheet of an overhead projector.
[0002]
[Prior art]
Recently, photopolymer method using UV curable resin as a manufacturing method of lens sheet that requires precise molding of fine irregularities such as Fresnel lens sheet, lenticular lens sheet, prism lens sheet, etc. A lens sheet is manufactured by the (2P method).
Regarding the manufacturing method of the lens sheet by the 2P method, the manufacturing method of the Fresnel lens sheet for the rear projection screen will be described as an example. Using a NC lathe, a metal plate is cut to form a concavo-convex pattern of a predetermined shape, and a mold is manufactured. The Fresnel lens sheet is formed by accurately transferring the shape to an ultraviolet curable resin.
With a Fresnel lens sheet for a rear projection screen, the time required for cutting one large mold for forming a Fresnel lens sheet such as a 60-inch size with an NC lathe is usually as long as 200 to 300 hours. .
[0003]
In order to increase the productivity per hour of the production line of the Fresnel lens sheet by the 2P method, it is necessary to prepare a plurality of dies, and the yield at the time of die cutting is not necessarily high. The cost of the mold occupies the manufacturing cost of the lens sheet. For this reason, it is desired to reduce the mold cost for molding one Fresnel lens sheet.
[0004]
In order to reduce mold costs, conventionally, there is a method using a resin double plate when molding this type of lens sheet.
For example, in Japanese Patent Application Laid-Open No. 10-323839, for example, an addition polymerization type silicone resin is injected into the concavo-convex pattern surface of a metal mold having a concavo-convex pattern of a predetermined shape, and is cured by heating at a first temperature, demolded, Mold a resin mold. A thermosetting epoxy resin, for example, is injected into the uneven pattern surface equal to the object to be molded formed in the silicone resin mold, heat cured at a second temperature, demolded, and an epoxy primary cured resin mold is molded.
The epoxy primary curing resin mold is heated and cured at a third temperature to mold the epoxy secondary curing resin mold. The use of this epoxy secondary curable resin mold as a mold for forming a lens sheet and a method for producing the same have been proposed.
[0005]
[Problems to be solved by the invention]
By the way, in the above-described method for manufacturing a mold for forming a lens sheet, in the heat curing of the first resin and the second resin, the temperature must be changed in three stages, ie, the first, second, and third temperatures. This complicates the process and requires a huge expense for the equipment.
Silicone resins and resins having a fluorinated polyether structure and silicone cross-linking reactive groups are excellent in dimensional stability. However, if similar materials are used for the first resin and the second resin, the mold cannot be released and the mold cannot be used. I can't get it.
In view of the above-mentioned points, the present invention provides a method for manufacturing a mold and a method for manufacturing a mold with stable dimensional accuracy, which can simplify the process and reduce the cost.
[0006]
[Means for Solving the Problems]
The invention according to claim 1 of the present invention is
A resin having a fluorinated polyether structure and a silicone cross-linking reactive group, which is a first resin, is injected into a female (concave) die of a metal mold provided with a concavo-convex pattern obtained by inverting the concavo-convex pattern of the molding. After curing at a temperature of, and releasing to create a resin male (convex) mold,
Applying a release agent to the resin male (convex) mold;
A step of injecting an addition polymerization type silicone resin as a second resin into the resin male (convex) mold and curing at a second temperature, followed by releasing to create a resin female (concave) mold. and,
A method for manufacturing a mold, wherein the first temperature and the second temperature are equal.
[0012]
That is, one of the first resin and the second resin is a silicone resin, and the other is a resin having a fluorinated polyether structure and a silicone crosslinking reactive group, so that the first temperature and the second temperature are equal. It can be temperature.
[0013]
Also, a first resin is injected into a metal mold and cured at a first temperature to create a resin male (convex) mold made of the first resin. At that time, a release agent is formed on the resin male (convex) mold. The first resin and the second resin can be applied using either a silicone resin or a resin having a fluorinated polyether structure and a silicone crosslinking reactive group, and the first temperature and the second resin can be used. The temperature can be made equal.
[0014]
From the above points, the temperature for curing the resin can be unified, simplifying the process and reducing the cost of equipment for it, and the second resin with silicone resin or fluorinated polyether structure with good dimensional stability and silicone By using a resin having a crosslinking reaction group, it is possible to produce a highly accurate resin mold.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, taking the present invention as an example, a manufacturing process of a Fresnel lens sheet is taken as an example, and a lens sheet mold and a manufacturing method thereof will be described with reference to FIG.
[0016]
[Example 1]
As shown in FIG. 1 (a), in the present invention, a female (concave) metal mold (1) having a concavo-convex pattern obtained by cutting a concavo-convex pattern of a Fresnel lens is obtained by cutting with a high-precision NC lathe.
Next, as shown in FIG. 1 (b), a resin having a general fluorinated polyether structure and a silicone crosslinking reactive group as a first resin is poured into the metal mold (1) in a vacuum, and the temperature is kept constant. By curing in a bath at 25 ° C. for 48 hours and demolding, a resin male (convex) mold (2) [FIG. 1 (c)] having an uneven pattern of a Fresnel lens is obtained.
Next, as shown in FIG. 1 (d), a general addition polymerization type silicone resin as a second resin is injected into the resin male (convex) mold (2) in a vacuum, and 25% in a constant temperature bath. The resin female (concave) mold (3) [FIG. 1 (e)] having a concavo-convex pattern in which the concavo-convex pattern of the Fresnel lens is inverted is obtained by curing at 80 ° C. for 48 hours and removing the mold.
The resin female (concave) mold (3) obtained above has the same shape as the metal mold of (a), and this is used as a mold for the production of a Fresnel lens sheet.
[0017]
[Example 2]
As shown in FIG. 2, in Example 1, the female resin (concave) was made in the same manner except that the fluorine-based mold release agent (4) was applied to the uneven pattern portion of the resin male (convex) mold (2). Mold (3) [FIG. 2 (e)] was prepared.
The resin female (concave) mold (3) obtained as described above is used for manufacturing a Fresnel lens sheet.
[0018]
【The invention's effect】
The remarkable effects of the present invention were as follows.
Precise curing that guarantees a wide temperature range from the first temperature to the third temperature, which was necessary until now, because the temperature environment is not changed by making the first temperature and the second temperature substantially the same. It is not necessary to install a furnace or a curing furnace for each of the first to third temperatures, and the cost of the equipment can be greatly reduced.
The step of secondarily curing the resinous female (concave) mold with the second resin at the third temperature can be omitted, and the time required for manufacturing the mold can be shortened.
[0019]
Since the first resin and the second resin were made of addition-polymerization type silicone resin with good dimensional stability and resin having a fluorinated polyether structure and a silicone crosslinking reactive group, a high-precision mold could be manufactured.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram illustrating steps of a method for producing a resin mold of the present invention.
FIG. 2 is a diagram illustrating a process of a method for producing a resin mold using a release agent of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Metal mold 2 ... Resin male (convex) type 3 ... Resin female (concave) type 4 ... Release agent

Claims (1)

A resin having a fluorinated polyether structure and a silicone cross-linking reactive group, which is a first resin, is injected into a female (concave) die of a metal mold provided with a concavo-convex pattern obtained by inverting the concavo-convex pattern of the molding. After curing at a temperature of, and releasing to create a resin male (convex) mold,
Applying a release agent to the resin male (convex) mold;
A step of injecting an addition polymerization type silicone resin as a second resin into the resin male (convex) mold and curing at a second temperature, followed by releasing to create a resin female (concave) mold. and,
The manufacturing method of the shaping | molding die characterized by making 1st temperature and 2nd temperature into equal temperature.

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