JPH08211205A - Continuous sheet inparted with optical function - Google Patents

Abstract

PURPOSE: To provide a continuous sheet which is imparted with optical functions, has no stripes and flaws on its surface and is cuttable to desired sizes. CONSTITUTION: This continuous sheet imparted with the optical functions by impartation of stereoscopic patterns is formed by melt extruding a thermoplastic resin 6 between the stereoscopic patterns surfaces of a continuous release sheet 2 having or not having the stereoscopic patterns on its surface and a continuous release sheet 2' having the stereoscopic patterns on the surface and transferring the stereoscopic patterns of these release sheets 2, 2' to the surfaces of the thermoplastic resin 6, then cooling the sheets and releasing and separating the sheets 2, 2' from the surfaces of the thermoplastic resin 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous sheet provided with a light function, and more specifically to a continuous release sheet having a desired three-dimensional pattern provided on the surface thereof, that is, (light) transmission. , A continuous plastic sheet having an optical function that exerts the functions of refraction, reflection, scattering, interference, polarization, etc., such as a plastic lens, a light reflection sheet, a prism sheet, an antiglare sheet, a diffusion sheet, etc., and a combination thereof. It relates to a continuous sheet.

[0002]

2. Description of the Related Art Today, films or sheets utilizing the optical characteristics of synthetic resins (hereinafter, referred to as sheets unless otherwise specified) are closely related to industry and daily life. However, most of them have a smooth surface condition, and the light transmittance is adjusted by simply competing for the transparency of the synthetic resin, or by matting the surface at most or adding additives. there were.

In recent years, a prism sheet, an antiglare sheet, and a diffusion sheet, which are one structural unit of a liquid crystal display used in a plastic lens, a notebook computer, a liquid crystal television, etc., have a special surface structure and are mainly used. Optical functional sheets that utilize the effects of reflection, refraction, scattering, etc., and sheets that combine these have been in the spotlight.

In order to form a three-dimensional pattern on a plastic surface, it is often manufactured by press molding or injection molding using a molding plate having a desired three-dimensional pattern. However, these have a problem that the productivity is inferior in the batch system or that a thin sheet-like product cannot be obtained. On the other hand, in order to manufacture a continuous sheet with a three-dimensional pattern, there is a method of extruding from a die of a different shape or molding the sheet with an appropriate embossing roll, but to give a precise pattern that gives optical performance Is difficult and, if at all, only some inaccurate patterns are obtained.

Therefore, in order to obtain a continuous sheet with a precise three-dimensional pattern, US Pat.
A method has been proposed in which a synthetic resin sheet material is clamped in a flat plate press die on a movable belt and pressed under pressure to continuously emboss. However, even with this method, it is not possible to make the three-dimensional pattern seamless and continuous optical functions.

The coating allows the production of patterned continuous sheets. One example is a method of coating fine particles to give a pattern. However, this method has the drawback that different substances are contained and only the pattern of the unit of fine particles can be obtained. Further, although a pattern can be imparted by a similar printing method, it is not possible to obtain a precise three-dimensional pattern imparting function so as to obtain optical performance.

[0007]

SUMMARY OF THE INVENTION In view of the above situation, the present invention is a prism sheet, a lens array, a lenticular lens such as a lens array, an antiglare sheet, a light diffusing sheet, etc. which requires a minute and precise three-dimensional pattern. Another object of the present invention is to provide a continuous optical functional sheet which can be cut into various sizes from these composite sheets and has good productivity.

[0008]

That is, the first aspect of the present invention is to:
On the three-dimensional pattern surface of a continuous release sheet having a three-dimensional pattern on the surface, a thermoplastic resin is melt-extruded, the three-dimensional pattern of the sheet is transferred to the surface of the thermoplastic resin, at the same time, the thermoplastic resin, Characteristic is that the uneven pattern or mirror surface of the surface of the cooling roll which is in contact with the surface opposite to the releasable sheet is used to form respective patterns on the surface of the thermoplastic resin which is in contact with the cooling roll, and the sheet is peeled and separated after cooling. , A continuous sheet with a light function by adding a three-dimensional pattern,

A second aspect of the present invention is that between a three-dimensional pattern surface of a continuous releasable sheet A having a three-dimensional pattern on the surface and a continuous releasable sheet B having or not having a three-dimensional pattern on the surface. The thermoplastic resin is melt-extruded, the three-dimensional pattern of the sheet A and the respective patterns of the sheet B are transferred to both surfaces of the thermoplastic resin, and then cooled, and then the sheets A and B are mixed with each other. A continuous sheet having an optical function by giving a three-dimensional pattern, which is characterized by peeling and separating from the surface,

In a third aspect of the present invention, a thermoplastic resin is provided between a light-transmitting base sheet or a sheet having an optical function and a three-dimensional pattern surface of a continuous release sheet having a three-dimensional pattern on the surface. It is melt extruded, the three-dimensional pattern of the release sheet is transferred to the surface of the thermoplastic resin and then cooled, and then the sheet is peeled and separated from the surface of the thermoplastic resin, and the thermoplastic resin and the transparent resin A continuous sheet provided with an optical function by imparting a three-dimensional pattern, characterized by laminating a base material sheet or a sheet having an optical function, respectively.

In general, it is difficult to directly obtain an optical functional sheet having a precise three-dimensional pattern directly from a metal molding roll. Therefore, in order to obtain a continuous sheet having an optical function by imparting a three-dimensional pattern, the present inventors first use a release sheet having a precise three-dimensional pattern and convert it into a thermoplastic resin having appropriate properties. Found that the copy method is the most effective

In order to obtain a release sheet having a precise three-dimensional pattern by means of a metal molding roll, even if it is unsuitable for optical characteristics and other required characteristics, it has good moldability and is suitable for the metal mold. By selecting a resin that provides excellent releasability, and by precisely selecting the molding processing conditions that give the best balance between moldability and releasability, a releasable sheet with a precise three-dimensional pattern that can provide an optical function can be obtained. I knew that I could get it. Examples of this resin include amorphous polyester, polyesters such as polybutylene terephthalate, polyethylene,
Polyolefins such as polypropylene and poly-4-methylpentene-1 can be mentioned. In particular, in order to obtain a precise three-dimensional pattern, crystalline polyolefins having a low glass transition temperature and a high crystal melting point are preferable because they have good moldability and excellent releasability.

In the processing of a continuous releasable sheet having a three-dimensional pattern, the extruded melt is pressed between the mold roll and the rubber roll to perform the molding. The most important molding condition is to select an appropriate temperature at which the mold roll temperature can be peeled. It is also possible to add a release agent in order to increase the releasability, and in this case, the temperature of the mold roll can be kept high. Furthermore, a mold release agent can be applied to the mold roll. Examples of the release agent include silicone oil, paraffin, wax, long-chain alkyl compound and the like, and these may be used alone or in combination of two or more kinds. In this case, care must be taken because if it is applied too much, the moldability is deteriorated and a precise three-dimensional pattern cannot be obtained.

For a continuous release sheet having a three-dimensional pattern, it is important to select a synthetic resin having heat resistance that can withstand the temperature at the time of transferring to a thermoplastic resin layer that is subsequently performed. From this point, polypropylene and poly-4-methylpentene-1 are advantageous. Further, an inorganic or organic filler may be added to improve heat resistance. However, even with these synthetic resins, if the temperature at the time of transferring to the thermoplastic resin that is subsequently performed is insufficient in heat resistance, heat or heat capable of increasing the heat resistance of the release sheet obtained by the above method or It can be used as a releasable sheet by molding with a composition curable by light. Epoxy type, urethane type, acrylic type and the like can be used for these compounds. Furthermore, if a material having high transparency and a high refractive index is selected from these compounds, it can be a product having an optical function similar to that of the present invention.

The three-dimensional pattern imparted is directly related to the light function of the continuous sheet. As a three-dimensional pattern, the cross section is an isosceles triangle with various apex angles, a large number of shapes such as an isosceles triangle which is slightly inclined, or prisms mixed with large and small triangles, a sinusoidal waveform, a cross section In addition to a semicircular lenticular lens with a large number of rows, a lens array with a large number of pyramid-shaped and hemispherical units, a matte, semi-matte, linear, mesh-like, fine irregularity pattern included. Here, in the case of a three-dimensional pattern having a shallow concavo-convex pattern or a pattern with low transfer accuracy, it is meaningless to use a releasable sheet because the pattern can be transferred directly from the embossing roll.

In principle, the thermoplastic resin to which the three-dimensional pattern is transferred may be any resin having sufficient thermoplasticity so that it can be satisfactorily imprinted at the time of transferring, for example, polyethylene terephthalate, polybutylene terephthalate, etc. Polyesters (including copolymers), polyamides, polycarbonates, polyarylates, polyether sulfones, acrylic polymers such as polymethylmethacrylate, polystyrenes, polypropylene, poly-4-methylpentene-1, Examples include polyolefins such as amorphous cyclic polyolefin. However, since the crystalline polyolefin is more easily molded by the direct molding roll, it is useless to transfer it again. Further, in order to have a higher optical function, it is required to have properties such as excellent transparency, high refractive index, and ability to withstand use environment conditions. Therefore, amorphous heat-resistant polyesters and polycarbonates are required. Also suitable are copolymers or modified transparent blends thereof, acrylic polymers such as polymethylmethacrylate, and amorphous cyclic polyolefins.

The thermoplastic resin is melt extruded between a continuous releasable sheet having a three-dimensional pattern on the surface and a cooling roll in contact with the opposite surface, and is pressed by a rubber roll from the back side of the releasable sheet to both sides thereof. Each pattern is formed. The surface of the cooling roll has an uneven pattern or a mirror surface. When a mirror surface is used, it becomes a sheet having an optical function with a three-dimensional pattern having one smooth surface, such as a prism sheet, a lenticular lens sheet or a lens array,
A continuous sheet having an optical function such as an antiglare sheet can be obtained. On the other hand, when the surface of the cooling roll has an uneven pattern such as matte, semi-matte, linear, mesh-like, or fine unevenness, it is not necessary to have the precision of the above-mentioned three-dimensional pattern, so transfer from the direct molding roll is possible. Is. In this case, since the respective optical functions can be imparted to both sides, it is possible to provide a continuous sheet having a composite optical function such as an antiglare prism sheet or a light diffusion prism sheet.

Between the continuous releasable sheets A and B having two kinds of three-dimensional patterns, the thermoplastic resin is pressed by a metal roll on one side and a rubber roll on the other side to transfer the respective three-dimensional patterns to both sides. It can have a light function. The two kinds of three-dimensional patterns may be the same kind or different kinds of combinations. Further, in the case of a combination of different types, either one of the release sheets A and B may be in a smooth state having no three-dimensional pattern.

In the case of the same kind of combination, if the prism sheet is taken as an example, even if the major axis directions of the prism having a triangular cross section are the same on both sides, they can be orthogonal to each other or can form an angle. . Of course, prisms of different sizes may be combined. In the case of different types, especially when using a release sheet having one smooth surface, a single continuous function such as a prism sheet, a lenticular lens sheet, a lens array and an antiglare sheet is used as in the case of using the above-mentioned mirror surface roll. A sheet is obtained. The difference from the mirror surface cooling roll is that by the so-called sandwich laminating method, the molten thermoplastic resin does not directly contact the cooling roll, streaks and scratches are not likely to occur on the surface of the thermoplastic resin, and sheets and patterns due to the aging effect Since it contributes to the improvement of dimensional stability, it is easy to obtain good quality. Furthermore, since the respective optical functions can be imparted by different kinds of combinations, it is possible to perform the two functions with one sheet without stacking the two sheets with the optical functions.

In order to obtain a laminated sheet of a translucent base material sheet and a thermoplastic resin having a three-dimensional pattern, a translucent base material sheet on one side and a continuous release sheet having a three-dimensional pattern on the other side are obtained. A so-called sandwich laminating method in which a thermoplastic resin is fed in and extruded between them is adopted. By this method, the sheet having the optical function can be provided with the characteristics of the translucent substrate sheet. For example, it is possible to provide a continuous sheet imparted with an optical function having transparency, mechanical properties such as tensile strength and elongation, and heat resistance and ring resistance, which a transparent substrate has.

The light-transmitting substrate sheet for this purpose is not particularly limited as long as it has heat resistance enough to withstand the temperature at which a three-dimensional pattern is transferred and applied, and examples thereof include polyethylene terephthalate and polybutylene terephthalate. Examples thereof include polyester, polyamide, polycarbonate, polypropylene, polyolefin-based synthetic resin sheets such as poly-4-methylpentene-1 (TPX), and laminated sheets thereof. In particular, biaxially stretched polyethylene terephthalate film is suitable. Furthermore, by applying a surface treatment such as anchor coating or corona treatment to these, lamination is promoted.

Further, when a sheet having an optical function is used instead of the translucent sheet, it is possible to obtain a laminated product having a combination of an optical function and an optical function by imparting a three-dimensional pattern. In this case also, it must have heat resistance to withstand the temperature at which the three-dimensional pattern is transferred and applied.
Examples thereof include polyvinyl alcohol-based polarizing films, polarizing films containing various dyes, retardation films, and ready-made optical functional sheets such as antiglare sheets. Further, if necessary, the sheet having the optical function, which has already been transferred to the three-dimensional pattern, is used on one surface, and the three-dimensional pattern is newly transferred to the other surface. Can be manufactured. In this case, the same kind of synthetic resin may be used, or different kinds of synthetic resin may be used. In the latter case, anchor coating or corona treatment is often effective for joining the two layers.

The continuous sheet provided with the optical function by imparting the three-dimensional pattern of the present invention obtained from the transfer at the time of the melt extrusion of the continuous release sheet having the three-dimensional pattern has the continuous optical function. Highly productive and high yield can be achieved because it can be cut into various sizes.

[0024]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

Example 1 Using the apparatus shown in FIG. 1, a biaxially stretched polyester film (Emblet S-50LS, 50) was fed from a second feeding machine.
μm, manufactured by Unitika Ltd.). Using a T-die extrusion laminator (screw diameter = 40 mm, L / D = 22), an amorphous cyclic polyolefin (“Apel” 6011T, manufactured by Mitsui Petrochemical Co., Ltd.) was used as a thermoplastic resin, and the T-die outlet resin temperature was 300 ° C. Extruded. On the other hand, as a continuous release sheet from the first feeding machine, poly-4-methylpentene- (TPX) having a thickness of 200 μm and having a sinusoidal pattern (FIG. 3) copied from a metal mold roll on its surface. (DX-820, manufactured by Mitsui Petrochemical Co., Ltd.) A sheet is drawn out, and this pattern surface is the above-mentioned “Apel”.
The melt-extruded "Apel" resin is placed in contact with the resin and pressed by a press roll so that the melt-extruded "Apel" resin is sandwiched in the center with the biaxially stretched polyester film, and the thickness of the extruded resin is 200 μm, and the laminator speed is 10 m / min
The poly sandwich lamination process was performed. After cooling with a cooling roll, the laminate I [release sheet (T
PX): three-dimensional pattern / “Apel” resin / biaxially stretched polyester film] to TPX having a sinusoidal three-dimensional pattern
The laminate is continuously peeled and separated, and wound on the first winder, and separated from the laminate II ["Apel" resin having a three-dimensional pattern transferred to the surface / biaxially stretched polyester film]
Was wound on the second winder. After that, the biaxially stretched polyester film was further peeled off from the laminate II by a rewinder, and the desired sinusoidal pattern surface was accurately transferred to the "Apel" resin surface, and the surface was free from streaks and scratches. Got the sheet. In the case of this method, the peeling and separating step can be simplified by one step. The continuous sheet is useful as a diffusion sheet for liquid crystal displays.

Example 2 TPX having a sinusoidal pattern in Example 1 on the surface
Instead of a continuous release sheet of the sheet, a cycle of 50 on the surface
A commercially available prism sheet (thickness: 230 μm) having a cross-section with a sawtooth pattern (FIG. 4) having a height of 21 μm and a lead film joined to the front and back of a commercially available prism sheet was used, and “Apel” was used as the thermoplastic resin. Amorphous polyester resin (glass transition temperature: 120 ° C, manufactured by Kanebo Co., Ltd.) was used (T-die exit resin temperature 280 ° C), and a biaxially stretched polyester film was not used, and a cooling roll having a mirror surface was used. Then, extrusion lamination was performed using the apparatus shown in FIG. Then, the release sheet was peeled and separated to obtain a continuous sheet having a thickness of 150 μm, in which the target serrated pattern surface was accurately transferred onto the surface of the amorphous polyester resin. This continuous sheet is useful as a prism sheet for liquid crystal displays.

Example 3 Instead of the TPX sheet having a sinusoidal pattern on the surface fed from the first feeding machine in Example 1, a saw-tooth pattern similar to that in Example 2 was taken from a metal mold ( 4) having a TPX sheet on its surface (continuous release sheet A), and replacing the biaxially stretched polyester film fed from the second feeding machine with the TPX sheet fed from the first feeding machine. TPX having the same sawtooth pattern as the above, but with a 90 ° rotation only in the direction of the top ridge, that is, having a sawtooth pattern orthogonal to the sawtooth pattern of the sheet fed from the first feeding machine.
A sheet (continuous release sheet B) is used, and the polycarbonate (S
P1010, manufactured by GE Plastics Co., Ltd.)
(T die exit resin temperature of 280 ° C.), but in the same manner as in Example 1, sawtooth-like patterns having different apex ridge line directions of 90 ° C. were accurately copied on the polycarbonate resin surface on the front and back sides of the object. A continuous sheet having a thickness of 200 μm and having no surface scratches or scratches and good dimensional stability was obtained. The continuous sheet is useful as a prism sheet, which is a backlight component for liquid crystal displays, as a sheet equivalent product obtained by superposing two one-sided three-dimensional patterned products.

[0028]

As described above, according to the present invention, it is possible to provide a continuous sheet which has a three-dimensional pattern on the surface and which has an optical function and which can be continuously produced at a low cost. The continuous sheet provided with the optical function of the present invention has no streaks or scratches on the surface,
Further, since the optical function itself is continuous, it can be freely cut into a desired size, and productivity and yield can be greatly improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an apparatus used in Example 1.

FIG. 2 is a schematic view showing an apparatus used in Example 2.

FIG. 3 is a schematic sectional view showing a sinusoidal pattern.

FIG. 4 is a schematic cross-sectional view showing a sawtooth pattern.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st feeding machine 2 and 2'The continuous mold release sheet which has a three-dimensional pattern 3 Press roll 4 Cooling roll 5 Extrusion laminator 6 (Melting) thermoplastic resin 7 2nd feeding machine 8 Base material sheet 9 Laminate and laminate I 10 winding machine, first winding machine 11 Laminated product II 12 second winding machine

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location G02B 5/00 Z (72) Inventor Hiiragi Ohara 4-13-18 Anritsu, Suminoe-ku, Osaka-shi, Osaka No. Goyo Paper Industry Co., Ltd.

Claims (6)

[Claims] 1. A thermoplastic resin is melt extruded onto a three-dimensional pattern surface of a continuous release sheet having a three-dimensional pattern on the surface,
The three-dimensional pattern of the sheet is transferred to the surface of the thermoplastic resin, and at the same time, the thermoplastic resin has an uneven pattern or a mirror surface on the surface of the cooling roll which is in contact with the surface opposite to the release sheet. A continuous sheet provided with an optical function by imparting a three-dimensional pattern, characterized in that each pattern is formed on the surface in contact with the cooling roll, and the sheet is peeled and separated after cooling. 2. A thermoplastic resin is melted between a three-dimensional pattern surface of a continuous release sheet A having a three-dimensional pattern on its surface and a continuous release sheet B having or not having a three-dimensional pattern on its surface. After extrusion, the three-dimensional pattern of the sheet A and the respective patterns of the sheet B are transferred to both surfaces of the thermoplastic resin and then cooled, and then the sheets A and B are peeled and separated from both surfaces of the thermoplastic resin. A continuous sheet provided with a light function by giving a three-dimensional pattern, which is characterized by the following. 3. A thermoplastic resin is melt-extruded between a translucent substrate sheet or a sheet having an optical function and a three-dimensional pattern surface of a continuous releasable sheet having a three-dimensional pattern on the surface, and the release is carried out. After the three-dimensional pattern of the moldable sheet is transferred onto the surface of the thermoplastic resin and then cooled, the sheet is peeled and separated from the surface of the thermoplastic resin, and the thermoplastic resin and a light-transmitting base material sheet or an optical sheet. A continuous sheet provided with a light function by giving a three-dimensional pattern, characterized by being laminated with a sheet having an optical function. 4. The continuous sheet according to claim 1, 2 or 3, wherein the optical function by giving a three-dimensional pattern is one of the functions selected from the functions of a prism, a lens, light scattering and a combination thereof. 5. The uneven pattern on the surface of the cooling roll is matte,
The continuous sheet according to claim 1, wherein the continuous sheet is at least one selected from an uneven pattern such as a semi-mat, a linear shape, a mesh shape, or fine unevenness. 6. The continuous sheet according to claim 3, wherein the sheet having an optical function is at least one selected from the function of imparting the three-dimensional pattern, light interference, and polarized light.