JPH0470603B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color polarizing plate whose main components are an organic polymer film or sheet and a dye. BACKGROUND ART Conventionally, as a polarizing plate using an organic polymer film, a so-called neutral gray-toned polarizing plate, which is a combination of a polyvinyl alcohol polymer film and iodine, has been used. There is a method of combining this type of polarizing plate with, for example, a liquid crystal display element to display black and white images, and this method is used for displaying a wide variety of calculators, meters, and the like. However, in recent years, in order to satisfy the demands for fashionability, product differentiation, and diversification of displayed information,
There is a demand for the development of a color polarizing plate that enables display in a desired color. Conventionally, this type of color polarizing plate has been produced by directly dyeing a hydrophilic polymer film such as polyvinyl alcohol with a dye or with a dye having a water-soluble group such as an acid dye, and then stretching it in a uniaxial direction. A color polarizing plate is known in which a polarizer is sandwiched between transparent protective plates such as acrylic resin plates or glass plates. This type of color polarizing plate is known from the Polymer Experimental Science Course 4, 111 (Kyoritsu Shuppan) and Japanese Patent Publication No. 1983.
- It is similar to that described in No. 90926, etc.
However, in recent years, with the expansion of the uses of such polarizing plates, there has been a strong demand for improved durability such as light resistance, moisture resistance, heat resistance, etc., as well as performance such as original polarizing ability. As a result, the above-mentioned conventional color polarizing plate made of a hydrophilic polymer film dyed with a linear dye or the like has a limit to the improvement in durability, and it has become impossible to satisfy such demands. The present inventors completed the present invention as a result of intensive research to satisfy such demands.
That is, the present invention relates to a color polarizing plate whose main components are an organic polymer film or sheet and a dye, in which the dye used is an anthraquinone-based dye having no water-soluble group and represented by the following formula (), or an anthraquinone-based dye having no water-soluble group; Phthalone series represented by or the following formula ()
Perylene structure represented by [In formula (), R ₁ and R ₂ may be the same or different, and each is a hydrogen atom, a hydroxy group, a nitro group, a halogen atom, or an amino group, and among R ₁ and R ₂ At least one is an amino group or a hydroxy group, and ring B is fused to the anthraquinone core (AQ) with the formula () ~
() A 5-membered ring represented by A ₂ is an alkyl group having 1 to 15 carbon atoms, a cyclohexyl group, or a cyclohexyl group having 1 to 15 carbon atoms.
represents a phenyl group optionally substituted with an alkoxyalkyl group or an alkyl group having 1 to 9 carbon atoms or an alkoxy group, X ₁ represents a halogen atom or a cyano group, and n is an integer of 0, 1, or 2. represents. ] [In formula (), X ₁ is a halogen atom or a cyano group, n represents 0, 1, or 2, and A ₃ is a hydrogen atom, a halogen atom, an alkoxycarbonyl group, or an optionally substituted phenoxycarbonyl group. group, p represents an integer of 1 or 2] [Formula () K, A ₃ and p represent the same meanings as in formula ()] Contains at least one dichroic dye having the following formula, and the base material of the organic polymer film or sheet is polyvinyl alcohol-based, polyvinyl alcohol-based, The present invention relates to a color polarizing plate characterized by being made of a vinyl chloride resin, a partially dehydrochlorinated polyvinyl chloride resin, a polyamide resin, or a polyester resin. According to the present invention, there is provided a color polarizing plate comprising an organic polymer film and a dye as main components, wherein the dye used is a dichroic dye having an anthraquinone-based, perylene-based, or phthalon-based structure that does not have a water-soluble group. Provided is a color polarizing plate characterized by containing at least one of the following. That is, the present invention is based on the fact that a color polarizer having excellent polarizing performance and durability can be obtained by dyeing or coloring an organic polymer film with a water-insoluble dichroic dye having a selected structural formula and stretching the film. Based on. As the organic polymer film or sheet, which is an important constituent base material of the color polarizing plate of the present invention, basically organic resin compounds having various linear molecular structures can be used, but polyvinyl alcohol-based , ethylene-vinyl acetate copolymer or its saponified product, cellulose, polyvinyl butyral, halogenated vinyl polymer, partially dehydrochlorinated halogenated vinyl polymer, halogenated vinylidene polymer, partially dehydrochlorinated halogenated vinylidene polymer , polyamide-based and polyester-based resin films or sheets can be used. Especially for use in areas where moisture resistance is required.
Those skilled in the art will readily understand that the use of halogenated vinyl polymer based, polyamide and polyester based resin films or sheets is preferred. Furthermore, the most important point of the present invention lies in the application of a water-insoluble dichroic dye having a selected structural formula to the polarizing plate. That is, the dichroic dyes of the present invention all have a rod-like molecular structure, exhibit strong visible light absorption in the direction parallel to the molecular axis, and exhibit almost no visible light absorption in the direction perpendicular to the molecular axis. It is a dye with so-called strong dichroism. By processing these dichroic dyes so that they are arranged in parallel in a certain direction in the linear polymer film or sheet, the linear polymer film or sheet can produce colored polarized light having excellent polarization properties. It is based on the principle of becoming a child. Even in the conventional technology, based on the above principle,
Various dyes have been proposed. However, for the dyes used in this field, it is important to dye the linear polymer film used as the base material, and so far, no material other than polyvinyl alcohol-based resin has been put to practical use as the base material. Therefore, only so-called direct dyes or acid dyes having a structure having a water-soluble group such as a sulfonic acid group, which are suitable for dyeing polyvinyl alcohol-based resins, have been studied. Furthermore, the fact that no water-insoluble dye having good dichroism has been found is one of the factors that has hindered the development of color polarizing plates with excellent durability. The discovery by the present inventors of a useful water-insoluble dichroic dye and its use in color polarizing plates has made it possible to improve the desired performance of color polarizing plates, especially the durability. In other words, as a linear polymer base material, we are not limited to polyvinyl alcohol base materials, which have traditionally been used despite having drawbacks such as hygroscopicity that can cause a decline in performance. It also allows the use of vinyl, polyamide, and polyester base materials. In particular, by combining the dichroic dye of the present invention with a linear polymer film based on polyvinyl chloride, polyamide, or polyester, a color polarizer with extremely excellent durability can be obtained. The color polarizing plate of the present invention can be manufactured by a conventional method. For example, a method in which a linear polymeric resin serving as a base material is fused and colored with the dichroic dye of the present invention, and then formed into a film or sheet shape and stretched; The organic solvent is evaporated to form a film.
A method of stretching the formed film, or a method of stretching the polymer resin, which has been previously formed into a film or sheet, after dyeing it with the dye of the present invention in a water or organic solvent dye bath; It is manufactured by a method in which the dye of the present invention is made into an ink, printed using the ink, and then stretched, etc., but the manufacturing method is not limited to the above example. It can be carried out without being affected. The amount of dichroic dye used in the polarizing plate of the present invention is not particularly limited, but in the case of a commonly used polarizer having a thickness of several microns to several tens of microns, the amount of dichroic dye used is 0.01 to 5% by weight based on the base resin, especially Preferably 0.01
A range of 2% by weight is suitable. Color polarizers manufactured in this way can be used as is, depending on the type of substrate or application, but polarizers with a protective film with excellent optical transparency and physical strength on one or both sides can be used. It can also be made into a board. Examples of materials for forming the protective film include glasses and synthetic resins that have optical transparency and excellent physical strength such as surface hardness. The protective film may be colored and may contain an ultraviolet absorber or the like as long as it has optical transparency. The surface protective film is usually attached to the polarizer using an adhesive that does not inhibit the polarizing ability of the color polarizer, such as a polyvinyl acetate adhesive, but other methods for forming the protective film include: It can also be obtained by coating and curing a polymeric resin that can be applied and cured on the polarizer surface. Typical examples of the polymeric resin include acrylic polymeric resins and urethane polymeric resins. Table 1 shows the color tone of transmitted light when two polyester-based polarizers (or polarizing plates) made using the water-insoluble dichroic dye of the present invention are stacked so that their stretching directions are perpendicular to each other. The relationship with the dichroic dye structural formula is illustrated. As a method of using the dichroic dye of the present invention in a polarizer, in addition to using the dichroic dye alone as shown in the example in Table 1, two or more dichroic dyes of the present invention may be mixed. It is also possible to use the dye of the present invention as a desired color tone, or to mix the dye of the present invention with other dichroic dyes or dyes without dichroism. Further, depending on the case, it is also possible to use a mixture of iodine or an iodine-based compound and the dichroic dye of the present invention, and the present invention can be practiced without being limited by such a combination. [Table] [Table] [Table] The dichroic dyes shown in Table 1 are representative examples of dyes that can be used in the present invention, and the dyes represented by the general formula in claim 1 are not limited in any way. It's not a thing. Hereinafter, a polarizing plate using a dichroic dye according to the present invention will be described with reference to specific examples. Example 1 Nylon 6 resin was melt extruded to form a substantially non-oriented film. This was stretched three times in the film forming direction using a roll method at a stretching temperature of 100 to 110°C. This stretched film was immersed in a finely dispersed aqueous solution (0.1% concentration) of dye No. 11 in Table 1 at 120° C. for 5 minutes to dye it pale blue. This dyed film was further stretched twice in the same direction as the above-mentioned stretching direction at a stretching temperature of 150° C. using a stretching tester. The transmittance of the thus obtained polarizing film in the visible region was measured using a spectrophotometer (UV-200 manufactured by Shimadzu), and the degree of polarization (V) was calculated based on the following formula. However, T ₁₁ indicates the transmittance when two polarizing films are stacked in parallel, and T⊥ indicates the transmittance when they are stacked at right angles. The degree of polarization at the maximum absorption wavelength of 690 nm was 91%, indicating good polarization properties. In addition, this polarizing film is heated at 80℃ and relative humidity is 90%.
After being left for two weeks under these conditions, there was almost no decrease in the degree of polarization, and it showed excellent moisture resistance. Example 2 500 parts of polyethylene terephthalate resin and 2 parts of dye No. 7 in Table 1 were sufficiently kneaded and melt-extruded to form a film. This colored film was stretched 6 times in the film forming direction using a stretching tester at a stretching temperature of 90 to 120°C. The degree of polarization at a wavelength of 506 nm using the same method as in Example 1 was 75%, indicating good polarization.
This film was processed under conditions of 80℃ and 90% relative humidity.
Although it was left for two weeks, there was almost no decrease in the degree of polarization, and it showed excellent moisture resistance. Example 3 Polyethylene terephthalate resin pellets 1Kg
Two parts of Dye No. 1 in Table 1 were added to the mixture and mixed uniformly, followed by melt extrusion, and a film with a thickness of about 100 μm was stretched in a tenter and heat-treated at 180° C. for several seconds.
A clear yellow polarized film is obtained, with a minimal absorption wavelength.
The degree of polarization at 480 nm was excellent at 85%. This polarizing film was placed under conditions of 80℃ and 90% relative humidity.
Although it was left to stand for a week, no change in hue or decrease in degree of polarization was substantially observed. Examples 4 to 9 Polarizing films were prepared in the same manner as in Example 3 using the various dyes shown in Table 1. Table 2 shows the results of the degree of polarization at the maximum absorption wavelength of each film obtained. 【table】

Claims (1)

[Scope of Claims] 1. In a color polarizing plate whose main components are an organic polymer film or sheet and a dye, the dye used is an anthraquinone-based dye having no water-soluble group and expressed by the following formula ( ) contains at least one type of dichroic dye having a phthalon-based structure or perylene-based structure represented by the following formula (), and the base material of the organic polymer film or sheet is polyvinyl alcohol-based or polyvinyl chloride. 1. A color polarizing plate characterized by being made of a partially dehydrochlorinated polyvinyl chloride-based, a polyamide-based, or a polyester-based resin. [In formula (), R ₁ and R ₂ may be the same or different, and each is a hydrogen atom, a hydroxy group, a nitro group, a halogen atom, or an amino group, and among R ₁ and R ₂ At least one is an amino group or a hydroxy group, and ring B is fused to the anthraquinone core (AQ) with the formula () ~
() A 5-membered ring represented by A ₂ is an alkyl group having 1 to 15 carbon atoms, a cyclohexyl group, or a cyclohexyl group having 1 to 15 carbon atoms.
represents a phenyl group optionally substituted with an alkoxyalkyl group or an alkyl group having 1 to 9 carbon atoms or an alkoxy group, X ₁ represents a halogen atom or a cyano group, and n is an integer of 0, 1, or 2. represents. ] [In formula (), X ₁ is a halogen atom or a cyano group, n represents 0, 1, or 2, and A ₃ is a hydrogen atom, a halogen atom, an alkoxycarbonyl group, or an optionally substituted phenoxycarbonyl group. group, p represents an integer of 1 or 2] [In formula (), A ₃ and p represent the same meanings as in formula ().] 2. The color polarizing plate according to claim 1, which has a protective film layer on one or both sides of the color polarizing plate.