JP4505387B2 - Light transmissive visibility control sheet - Google Patents

Description

  The present invention relates to a visual field control sheet having visual field controllability that allows light to pass in a specific range direction but not to light in other directions, and a method for manufacturing the same.

  Conventionally, as a sheet having visibility controllability, for example, there are technologies disclosed in Patent Document 1, Patent Document 2, and Patent Document 3.

  Patent Document 1 discloses a technique of obtaining a sheet having visibility controllability by slicing a surface layer in a direction perpendicular to the stacking direction after alternately laminating transparent and black disks to obtain a desired thickness. Has been.

  Patent Document 2 describes a field-of-view control film that selectively scatters light at a specific incident angle by irradiating and curing ultraviolet rays from a certain direction. In this technique, it is also possible to selectively scatter and control light in two or more directions by applying an ultraviolet curable resin as necessary, and curing by irradiating with ultraviolet rays from other directions.

  Furthermore, in Patent Document 3, a transparent polymer resin film having molecular orientation is folded using a blade or the like so that the molecular orientation direction and the blade edge are parallel, and in this state, the direction perpendicular to the molecular orientation direction. The technique for generating a visual field control film by generating striped crazes continuously in parallel with the molecular orientation direction by taking the film into the film is described.

Japanese Patent Publication No. 47-43845 Japanese Unexamined Patent Publication No. 63-309902 JP-A-6-82607

  However, the technique disclosed in Patent Document 1 described above has a disadvantage that the transparent portions and the black portions must be alternately laminated until the desired thickness is reached, resulting in poor productivity and high cost. The sheet obtained by this technique has only visibility control from one direction.

  Since the technique disclosed in Patent Document 2 is a transmission control of obliquely incident light by reflection and scattering, the technique does not completely block light. In addition, a special ultraviolet curable resin is used, and production is performed through a process called curing, which is also expensive. In addition, with this technique, it is possible to obtain a sheet having visibility controllability in two or more directions. For this purpose, after manufacturing a sheet having visibility controllability from one direction, further application of UV curable resin, UV irradiation This is a very low productivity.

  Furthermore, in the technique shown in Patent Document 3 presented as improving these defects, a film substrate having molecular orientation must be used. As a film having such characteristics, a uniaxially stretched film is disclosed. In this case, a uniaxially stretched film in the TD direction is essential in order to continuously produce a crazing visibility control film. This is technically difficult and is not highly productive. In order to form a craze, the film substrate must be pressed against the blade and pulled with a relatively large force, and this operation causes many scratches on the substrate. Moreover, what was obtained by this technique has only one-direction visibility controllability.

The present invention has been made to solve the above-described problems, and provides a light-transmitting visual field control sheet that can be manufactured very easily at low cost, has good visual field controllability, and has multidirectional visual field controllability. The purpose is to provide.

The light-transmitting field-of-view control sheet in the present invention is formed by laminating a non-oriented light-transmitting polymer layer having two or more regular directional cracks on a light-transmitting substrate, The conductive polymer layer is pulled by applying tension in the direction perpendicular to the blade of the blade while applying the blade to the light transmissive substrate side of the laminate, or by partially forming a bent portion to form a crack. Further, similar treatment is performed in the other direction, and this is repeated to form cracks in two or more directions .

  Here, “regularity” means regularity in the bending direction and thickness direction.

  Furthermore, the term “non-oriented” means that the material is not intentionally oriented by a method such as stretching during production. Specifically, the stretch ratio is in the range of about 1: 1.2 to 1.2: 1 (longitudinal direction: lateral direction).

  That is, the present invention has a crack having a regular directionality by applying a force in a regular direction beyond the generation of a crack by bending or the like to a sheet having a non-oriented light-transmitting polymer layer. A view control sheet is obtained. Here, a single-layer non-oriented light-transmitting polymer sheet is obtained by hot pressing or melt extrusion, and a sheet in which a non-oriented light-transmitting polymer layer is laminated on a light-transmitting substrate is a polyester film or the like. It can be obtained by coating or melt-extrusion film formation on a light-transmitting substrate, and further by coextrusion film formation.

  Furthermore, by providing a light-absorbing substance, a light-scattering substance, or the like in the generated crack, a product with improved visibility control can be obtained.

  The “sheet” used in the present invention means not only “sheet” in a narrow sense but also “film”.

  According to the present invention, a sheet having good visibility controllability can be obtained very easily at low cost.

  In addition, a sheet having multi-directional visibility control can be easily produced at low cost as required.

  The obtained visibility control sheet is attached to a display of an OA device, an on-vehicle meter of an automobile, an outdoor display, and a window, so that favorable visibility control can be performed.

  Hereinafter, the sheet having visibility controllability according to the present invention will be described in detail.

  The light transmissive polymer layer in the present invention is composed of a polymer material having light transmissive properties. The polymer material may be of any kind such as thermoplastic, thermosetting, and ultraviolet curable as long as it can cause cracks. Examples include polystyrene, styrene acrylonitrile, acrylonitrile butadiene styrene, styrene butadiene, and other styrenic resins, polymethyl methacrylate, polyvinyl chloride, polyvinylidene fluoride, nitrocellulose, and other thermoplastic resins, epoxy, phenol, and unsaturated polyester. And other ultraviolet curable resins. Two or more of these resins can be mixed and further mixed with other resins. A particularly preferred material is polystyrene.

  Next, a method for obtaining a visibility control sheet using the above-described polymer material will be specifically described.

  The polymer material is formed into a sheet by taking out the polymer material to such an extent that it is not subjected to molecular orientation by hot pressing or melt extrusion. The obtained sheet 1 is pulled by applying a slight tension in a direction perpendicular to the blade 2 while applying the blade 2 so that the sheet 1 is bent appropriately (FIG. 1), or partially bent on the sheet 1 By taking the part 3 while making it (FIG. 2), a visibility control sheet having visibility controllability with cracks 4 in the direction perpendicular to the take-off direction is obtained (FIGS. 3 and 4). Here, the downward arrows in FIGS. 1, 2 and 3 indicate the take-up direction.

  After obtaining visibility controllability in one direction in this manner, the same treatment is further performed in the other direction, and this is repeated as necessary to obtain a visibility control sheet having visibility controllability in two or more directions. (FIG. 5).

  The thickness of the sheet is not particularly limited, but it is preferably 100 μm or less because it affects workability when forming a crack. The bending angle and the degree of bending for forming a crack are related to the thickness and material.

  Furthermore, the ambient temperature when forming cracks is also important. In other words, even if the same polymer material is used as the polymer material of the light-transmitting polymer layer, cracks may or may not occur depending on the ambient temperature during folding, which is related to the properties of manufacturing and products. .

  The outline is as follows. For example, when a polymer material that cracks at room temperature is selected, it can be manufactured at room temperature, which is extremely beneficial from the viewpoint of productivity. However, the visibility control sheet obtained using such a material has a high risk of being newly cracked by being bent regardless of whether it is desired or not. Therefore, in order to protect this, it is necessary to laminate on a base material such as plastic having an appropriate hardness so as not to be bent, or to attach it to a required place.

  Conversely, when a polymer material that cracks only at a low temperature such as 0 ° C. or lower is selected, it is necessary to create a low-temperature atmosphere environment when cracks are generated, which is disadvantageous in terms of productivity. However, the visibility control sheet obtained using such a material does not cause unnecessary cracks even if it is bent in the other direction at room temperature. For these reasons, it is necessary to select an appropriate light-transmitting polymer material according to the purpose.

  It is also possible to add a pigment or the like to the sheet and color it in a desired color, or to achieve a desired transmittance as a whole.

  Moreover, as mentioned above, the obtained sheet | seat can also be bonded together to another base material. If necessary, a base material such as a polyester film or a resin coating film can be laminated on the light-transmitting polymer layer in which cracks are further formed.

  Next, a method for obtaining a visibility control sheet by a coating method will be described with reference to FIG. A coating film is formed by dissolving the above-described polymer material in a suitable solvent to obtain a coating solution, and coating and drying the coating material on a light-transmitting substrate 6 such as a polyester film using a wire bar or the like. In the same manner as described above, by applying tension to the blade and pulling it in the direction perpendicular to the blade of the blade, or pulling it while partially forming a bent part, cracks 4 enter in the direction perpendicular to the take-up direction. A visibility control sheet having the light-transmitting polymer layer 5 is obtained (FIG. 6). It is possible to have visibility controllability in two or more directions, the influence of the atmospheric temperature at the time of crack formation, the addition of pigments, etc., coloring to a desired color, or making the whole desired transmittance What can be done is the same as described above. Further, it is possible to add a surfactant to improve the coating property, and an AS agent such as a quaternary ammonium salt to impart AS property, and it is often useful.

  Moreover, in order to raise the adhesiveness between the light-transmitting base material 6 and the light-transmitting polymer layer 5, or to obtain AS property, an easy-adhesion layer and an AS layer can be provided between them, respectively.

  Similarly, a non-oriented light-transmitting polymer layer 5 is formed on a light-transmitting substrate 6 such as a polyester film by melt extrusion instead of coating, and then the same treatment is performed, so that the direction perpendicular to the take-off direction is obtained. A view control sheet having cracks 4 can be obtained. It is possible to have visibility controllability in two or more directions, the influence of the atmospheric temperature at the time of crack formation, the addition of pigments, etc., coloring to a desired color, or making the whole desired transmittance It is the same about what can be done.

  Furthermore, a method using coextrusion is also effective. First, a laminated sheet is produced by co-extruding from a T-die while taking a polymer material having optical transparency such as polyethylene as a base material and the above-described polymeric material for the optically transparent polymer layer so as not to be molecularly oriented. . Here, a coextruded laminated sheet of three or more layers having layers 7 (protective layers) of polyethylene or the like above and below the light transmissive polymer layer 5 may be used (FIG. 7). By performing the same process on the obtained sheet, a visibility control sheet having cracks 4 in the direction perpendicular to the take-up direction can be obtained. The same applies to the fact that it is possible to provide visibility control in two or more directions, the influence of the ambient temperature at the time of crack formation, and the like.

  Moreover, a light-absorbing substance can be provided in the crack formed by the present invention, and the visibility controllability can be further improved. The light-absorbing substance used may have any color, and the type of dye, pigment, etc. is not limited. Preferable materials include pigments such as carbon black, iron black, molybdenum red, and blued blue, and various dyes. Black dyes such as carbon black and aniline black are particularly desirable because of their effects. Furthermore, even if the substance provided in the crack is a light scattering substance, good visibility controllability can be obtained. Examples of such substances include extender pigments such as zinc oxide, titanium dioxide, calcium carbonate, and silica, and metal powders such as aluminum powder.

  These substances are usually used by dissolving or dispersing in a solvent, but a resin can be further added thereto and used together with the resin.

  In order to apply these substances into the cracks, the obtained visibility control sheet may be immersed in the solution as it is, but it is more efficient to slightly fold the visibility control sheet and immerse it in a state where the cracks spread. It is.

  Furthermore, after making an additive exist in a crack, a protective layer can also be laminated | stacked on a light transmissive polymer layer.

  Examples of the present invention will be described below.

[ Reference Example 1]
A polystyrene resin (666R: Asahi Kasei Kogyo Co., Ltd.) is dissolved in a mixed solvent of methyl ethyl ketone and toluene, applied onto a transparent polyester film having a thickness of 50 μm with a wire bar, and then dried by heating, whereby a light transmittance of 30 μm is obtained. A molecular layer was formed.

  Next, the laminated body was taken up with a PTFE blade having a 50 degree angle applied to the polyester side, and cracks were continuously generated in the light-transmitting polymer layer to obtain a visibility control sheet.

  In the obtained visibility control sheet, the polyester film remained transparent, and the light-transmitting polymer layer had cracks in the film thickness direction.

  Although it still has visibility controllability, in order to make the effect more remarkable, it was immersed in the following black coloring liquid and the crack portion was colored black.

<Black coloring liquid composition>
・ Acrylic acid / Methyl methacrylate /
2-hydroxyethyl methacrylate copolymer (copolymerization ratio = 1/4/5) 5 parts by weight, carbon black MA-100 (Mitsubishi Chemical Corporation) 5 parts by weight, ammonia water (reagent) 3 parts by weight, water 77 Part by weight / Isopropyl alcohol 10 parts by weight

  This black-colored visibility control sheet showed better visibility controllability.

[ Reference Example 2]
After forming a polystyrene resin coating film on a polyester film in the same manner as in Reference Example 1 , this laminate was entangled in a roll with a diameter of 5 mm, and then continuously cracked in the polystyrene layer (light transmissive polymer layer). Was generated.

  The obtained visibility control sheet remained transparent with no damage to the polyester film, and the polystyrene layer had cracks in the film thickness direction, and had good visibility controllability.

[ Reference Example 3]
Polystyrene resin (666R: Asahi Kasei Kogyo Co., Ltd.) was melted and hot pressed to obtain a sheet having a thickness of 50 μm.

This sheet was continuously bent in the same manner as in Reference Example 1 to generate cracks in the direction parallel to the blade, thereby obtaining a visibility control sheet. Although this sheet had visibility controllability, a blue visibility control sheet was obtained by blue-coloring the crack portion with a blue coloring liquid having the following composition. This visibility control sheet had good visibility controllability.

<Blue coloring liquid composition>
・ Blue dye (Victoria Pure Blue FGA: Hodogaya Chemical Co., Ltd.) 5 weight parts ・ Ethyl alcohol 95 weight parts

[Example 1 ]
Acrylonitrile / styrene copolymer (Cebian N020: Daicel Chemical Industries) is dissolved in a mixed solvent of methyl ethyl ketone and toluene, coated on a transparent polyester film with a thickness of 25 μm with a wire bar, and then heated to dry to transmit light with a thickness of 50 μm. The sheet | seat in which the conductive polymer layer was formed was obtained.

This sheet was continuously bent using the blade of Reference Example 1 to generate cracks. Subsequently, a second view was bent perpendicularly to the first bending direction to produce a visibility control sheet in which cracks were generated in both the vertical and horizontal directions.

  This visibility control sheet had visibility controllability not only in the vertical direction but also in the horizontal direction.

[ Reference Example 4 ]
Acrylonitrile / styrene copolymer (Litec 100PC: Mitsui Toatsu Chemical Co., Ltd.) and high-density polyethylene resin (6100A: Tosoh Corp.) were coextruded from a T-die while pulling them to such an extent that they were not molecularly oriented to produce a laminated sheet. The thickness of each layer was 50 μm.

This sheet was folded with the blade of Reference Example 1 to continuously generate cracks in the acrylonitrile / styrene copolymer layer.

  This sheet also had visibility controllability.

The figure which shows one Example of the manufacturing method of the visibility control sheet | seat of this invention. The figure which shows the other Example of the manufacturing method of the visibility control sheet | seat of this invention. The figure which shows the other Example of the manufacturing method of the visibility control sheet | seat of this invention. The figure which shows one Example of the visibility control sheet | seat of this invention. The figure which shows the other Example of the manufacturing method of the visibility control sheet | seat of this invention. The figure which shows the other Example of the visibility control sheet | seat of this invention. The figure which shows the other Example of the visibility control sheet | seat of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Sheet 2 ... Blade 3 ... Bent part 4 ... Crack 5 ... Light transmissive polymer layer 6 ... Light transmissive substrate 7 ...・ Protective layer

Claims (4)

On the light transmitting substrate, Ri name by stacking a light-transmitting polymer layer of non-oriented regular orientation of cracks occurs more than one direction, the light-transmitting polymer layer of the laminate A crack is formed in one direction by applying a tension in the direction perpendicular to the blade of the blade while applying the blade to the light transmissive substrate side, or by partially creating a bent portion, and the same in the other direction. A light-transmitting visual field control sheet characterized in that cracks are formed in two or more directions by performing various treatments and repeating this .   The light-transmitting visual field control sheet according to claim 1, further comprising an additive in a crack portion.   The light-transmitting visual field control sheet according to claim 2, wherein the additive is a light-absorbing substance.   The light-transmissive visual field control sheet according to claim 2, wherein the additive is a light-scattering substance.

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