JPH06234156A - Manufacture of emboss sheet - Google Patents

Abstract

PURPOSE:To manufacture an emboss sheet efficiently by applying thermosetting raw liquid to an emboss molding matrix, placing a base sheet on the matrix to form a base emboss sheet and fixing by pressure, curing the thermosetting raw material liquid and forming an emboss section. CONSTITUTION:In the manufacture of an emboss sheet such as an optical record medium or a Fresnel lens sheet, an emboss molding matrix 3 provided with a lining layer 1 of sufficiently large heating capacity and an emboss shape metal layer 2 is heated preliminarily lower than a polymerization starting temperature for thermosetting raw material liquid 4, and the raw material liquid 4 is applied on the matrix 3. Then, a base sheet 5 composed of acryl, polycarbonate and the like heated to the temperature higher than the polymerization starting temperature for the raw material liquid 4 preliminarily is placed on the raw material liquid 4 and fixed by pressure. The raw material liquid 4 is heated by a base sheet 5 and polymerization reaction is started, and the sheet is retained for a given time to cure the raw material liquid 4. After that, the matrix 3 is released to manufacture a molded product with an integrated emboss section.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the manufacture of flat embossed sheets, and is particularly suitable for the manufacture of optical recording media, Fresnel lens sheets and the like.

[0002]

2. Description of the Related Art Conventionally, as a molding technique for an optical recording medium or a Fresnel lens sheet, there are a pressing method, a rolling method, a casting method, a method using a UV curable resin and the like. Among them, the casting method is a method of injecting a reactive raw material liquid such as a resin or a monomer in a fluid state into a cell composed of a molding die and a sealing material to cause reaction curing, and then releasing the molded product from the mold. When a thermosetting resin is used as the liquid, the polymerization reaction is carried out by heating the entire cell in a heating furnace, and therefore the molding die must be cooled for the next cycle after the molding is completed. In addition, the method using the UV curable resin is such that the UV curable resin is applied onto the embossing mold, the base sheet is stacked on the master die and then pressure-bonded, and UV irradiation is performed to cure the UV curable resin to form a base sheet. It is a method of integrating UV curable resin.

[0003]

However, although the molded product molded by the above-mentioned conventional casting method has good shape accuracy, since the reactive raw material liquid is cured by heating the entire cell in a heating furnace, It takes a long time to reach the reaction start temperature, and then it takes about 15 to 40 minutes to return the molding die to the optimum temperature of the material injection step, resulting in low productivity. . Further, the UV method has a problem that it requires a step of applying a primer for adhering the UV curable resin and the base sheet to the base sheet, and is expensive in terms of cost.

[0004]

Means for Solving the Problems The method for producing an embossed sheet according to the present invention was obtained as a result of an examination to solve the above problems, and a thermosetting raw material liquid was applied to a mother die for embossing, A base sheet, which is the base material of the embossed sheet, is placed on top of it and pressure-bonded to cure the thermosetting raw material.
The method for producing an embossed sheet is characterized by forming an embossed portion on the base sheet. Further, the master mold is adjusted to a temperature lower than the polymerization start temperature of the raw material liquid, the raw material liquid is applied onto the master mold, and a base sheet heated to a temperature higher than the polymerization start temperature of the raw material liquid is placed on the master mold. The method for producing an embossed sheet is characterized in that the embossed sheet is loaded on the above-mentioned raw material liquid applied to the sheet and pressure-bonded. Here, as the thermosetting raw material liquid, it is preferable to use a redox polymer material that can initiate polymerization at a low temperature and has a fast reaction rate.

In the present invention, the embossing mother die can be formed of a metal layer having an embossed shape having excellent thermal conductivity and thermal diffusivity, and a backing layer under the metal layer having a large heat capacity for keeping heat. .

[0006]

According to the present invention, the heating / cooling step of the molding die, which is a bottleneck in shortening the process time, is unnecessary, so that the polymerization reaction of the material can be efficiently performed in a short time, and the productivity can be improved. It is possible. Furthermore, if the same material as the reactive raw material liquid is used as the material of the base sheet, the step of applying an adhesive material such as a primer is unnecessary,
It is possible to provide a method for manufacturing an embossed sheet that is rational and has good workability.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings. First, as shown in FIG. 1, an embossing mold 3 having a backing layer 1 having a sufficiently large heat capacity in the lower part and a metal layer 2 having an embossed shape in the upper part is preliminarily polymerized with a thermosetting raw material liquid 4. The temperature is adjusted to be lower than the temperature, and the thermosetting raw material liquid is applied onto this mother die. On the other hand, the base sheet 5 in advance
Is heated to a temperature higher than the polymerization initiation temperature of the thermosetting raw material liquid. Although the metal layer is shown in the shape of the Fresnel lens here, a desired metal layer may be formed depending on its application. The material of the metal layer 2 is nickel, aluminum, brass or the like, which is excellent in heat transfer property and heat diffusion property, and the material of the backing layer 1 is ceramic, glass, stone or the like. In addition, acrylic, polycarbonate, polystyrene or the like is used as the material of the base sheet 5. Thermosetting raw material liquid 4
Is a redox polymer material having a short polymerization time, and if necessary, additives such as a light diffusion adjusting agent, an antistatic agent, a flame retardant, and a coloring agent can be added. Next, as shown in the drawing, the base sheet 5 is stacked on the thermosetting raw material liquid 4 applied on the mother die 3. The thermosetting raw material liquid is heated by the base sheet 5 in contact therewith to start a polymerization reaction, and the thermosetting raw material liquid 4 is cured by holding the base sheet at room temperature for a certain period of time. At this time, since the mother die has a large heat capacity of itself, the temperature is not largely changed by leaving it at room temperature. The temperature of the base sheet 5 and the temperature at which the thermosetting raw material liquid 4 is applied are different depending on the type of the thermosetting raw material liquid, the heat capacity of the matrix, and the like, and may be appropriately determined accordingly. After the above-mentioned polymerization reaction is carried out for a certain period of time, a molded product in which the base sheet 5 and the embossed portion made of the cured thermosetting raw material liquid are integrated is taken out from the mother die 3.

FIG. 2 is an explanatory view showing an embodiment in which molding by the method of the present invention is continuously carried out. In this embodiment, as shown in FIG. 2, coating, loading, nip curing
It consists of 6 steps of release and transfer. According to the method of the present invention, the base sheet 5 is heated by a heat controller, and the mother die 3
The thermosetting raw material liquid and the base sheet are integrated with each other by stacking them on the reactive raw material liquid 4 applied thereon, press-bonding and curing. On the other hand, the mother mold 3 releases the molded product, takes it out, and then conveys it for use in the second process again. Since the mother die has a sufficiently large heat capacity, the temperature of the mother die is not affected by the heat of the acrylic base plate loaded at room temperature during the coating, nip, and curing processes, and the heat of reaction of the thermosetting raw material liquid. Absent. Therefore, the temperature control step required during the cycle is only the heat retention step during transportation. As described above, in the present invention, the heating and cooling steps of the mold can be eliminated, and the cycle time can be shortened.

Hereinafter, the present invention will be described in more detail with reference to specific examples of the present invention. As a redox-based polymerization material, a resin solution in which hydroperoxide as an oxidizing agent was added to an MMA monomer and a resin solution in which mercaptan as a reducing agent was added were used, and both solutions were mixed at room temperature. The polymerization temperature of this system was about 70 ° C., and the Fresnel lens type temperature adjusted in advance from this polymerization temperature was set to 40 ° C. Since this Fresnel lens type is provided with a backing 2 having a sufficiently large heat capacity, it can be considered that the temperature of the polymer material 3 flowed on the backing 2 is 40 ° C. Therefore, the amount of heat required to heat the polymer material 3 at 40 ° C. to 70 ° C. is 297 because the amount of the polymer material 3 required is 220 g.
The calorie can be calculated as 0 calories, and this amount of heat is used as the base sheet 4 (93 × 120) made of an acrylic plate loaded on the polymer material.
X0.3 cm ³ , 4018 g), the temperature of the base sheet 4 was set to 90 ° C in consideration of the amount of heat that the base sheet 4 radiates into the atmosphere. Polymerization is completed by coating the above mixture on the Fresnel lens mold whose temperature is adjusted to 40 ° C., loading an acrylic plate heated to 90 ° C. on it and pressing it, and then leaving it at room temperature for 5 minutes. Then, a Fresnel lens sheet was produced. The redox-based polymer material may additionally use benzoyl peroxide as an oxidizing agent and dimethylaniline as a reducing agent.

[0010]

As described above, since the polymerized material is polymerized by the heat energy of the heated base sheet loaded on the polymerized material on the embossing mold whose temperature is kept constant, the heating is not performed. Since it can be performed promptly and there is no need to use a heating furnace as in the conventional method, there is no need for a large-scale facility, and the cost of the facility can be reduced. In addition, since the mother die has a sufficiently large heat capacity of itself, it is not significantly changed in temperature by the amount of heat of the acrylic base plate to be left at room temperature in the coating, nip, and curing processes, the heat of the acrylic base plate to be loaded, and the reaction heat of the polymer material. Since the only temperature control step required during the cycle is the heat retention step during transportation, there is no need for the heating and cooling steps of the mother die, and the process time can be greatly shortened and productivity can be improved. it can. Further, since a redox polymerization material is used as the thermosetting raw material liquid, polymerization can be initiated at a low temperature, and heating can be performed in a short time because of a high reaction rate,
Workability is improved. Furthermore, as the material of the base sheet,
Since the same system as the thermosetting raw material liquid can be used, the step of applying an adhesive material such as a primer is not necessary, and a method for manufacturing an embossed sheet that is rational and has good workability can be provided. .

[Brief description of drawings]

FIG. 1 is a diagram showing a method for manufacturing an embossed sheet according to the present invention.

FIG. 2 is a diagram showing steps in the case where molding according to the present invention is continuously performed.

[Explanation of symbols]

 1 Backing layer with sufficiently large heat capacity 2 Metal layer having embossed shape 3 Embossing mold 4 Thermosetting raw material liquid 5 Base sheet

Claims (3)

[Claims] 1. A thermosetting raw material liquid is applied to an embossing mold, and a base sheet, which is a base material of an embossing sheet, is placed thereon and pressure-bonded to cure the thermosetting raw material liquid.
A method for manufacturing an embossed sheet, comprising forming an embossed portion on the base sheet. 2. A base sheet prepared by adjusting the master mold to a temperature lower than the polymerization start temperature of the raw material liquid, applying the raw material liquid onto the master mold, and heating the base sheet to a temperature higher than the polymerization start temperature of the raw material liquid, The method for producing an embossed sheet according to claim 1, wherein the raw material liquid is applied onto the mother die, and the raw material liquid is cured by pressure bonding. 3. A mold for embossing, comprising a metal layer having an embossed shape on one side and a backing layer provided on the surface of the metal layer opposite to the embossed surface for heat retention. The method for producing an embossed sheet according to claim 2, which comprises: