JPH09127334A - Polarizing woven fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polarizing woven fabric having excellent polarizing characteristics, weather resistance, water resistance, moisture and heat resistance, chemical resistance and soil resistance. SOLUTION: This fabric is produced by using a polarizing fiber having the following features for at least either of the woof or the warp. The fiber consists of a polyvinyl alcohol or ethylene-vinylalcohol copolymer having >80% transmittance for light, >=10.cc.mil/100in<2> .24hr.atom oxygen permeability, and <=5g/m<2> .24 hr.0.1mm moisture permeability and the fiber is coated with a fluorocarbon polymer containing a UV absorbent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarizing woven fabric for screens used in video systems equipped with a liquid crystal display, which has excellent polarization characteristics and weather resistance, water resistance, wet heat resistance, and chemical resistance. The present invention relates to a polarizing woven fabric having excellent antifouling property.

[0002]

2. Description of the Related Art A liquid crystal display system is smaller than a cathode ray tube image system in that it can be installed in a relatively narrow space, it is light in weight and easy to move, and because it is a digital image, it is easy to adapt to image processing. With such advantages, the utilization rate has increased dramatically. It is used not only indoors but also outdoors.
However, for example, when it is applied to a recent liquid crystal display device and mounted in an automobile, the device is exposed to high temperature, high humidity, and ultraviolet rays, so that there arises a problem that the polarization characteristics are significantly deteriorated, and there is a difficulty in practical use. . Therefore, in order to further popularize liquid crystal display devices such as office automation equipment and desk-top computers, high temperature and high humidity resistance without degrading the polarization characteristics,
There is a demand for a polarized woven fabric that has excellent durability such as ultraviolet resistance and can withstand more severe conditions.

[0003]

The cause of the deterioration of the performance of the polarizing woven fabric due to the use under severe conditions is that the polarizing woven fabric is deteriorated by the synergistic action of heat and humidity, and further by ultraviolet rays. The present inventors have focused their attention on a resin layer for protecting a polarizing woven fabric, and as a result, have a specific light transmittance, an oxygen transmission coefficient, a moisture permeability, and a fluorine-containing polymer containing an ultraviolet absorber as a protective resin. By using it as a layer, it has been found that the above problems can be solved.

[0004]

The present invention is a polarizing fiber comprising a polyvinyl alcohol or an ethylene-vinyl alcohol copolymer having a light transmittance of 80% or more,
Oxygen permeability coefficient is 10cc ・ mil / 100in ²・ 24
less than hr ・ atm, moisture permeability of 5g / m ²・ 24hr ・
A polarizing woven fabric in which a fiber having a diameter of 0.1 mm or less and coated with a fluoropolymer containing an ultraviolet absorber is used for at least one of warp and weft, and polyvinyl alcohol or ethylene. -A polarizing woven fabric comprising a polarizing fiber made of a vinyl alcohol-based copolymer as at least one of warp and weft, wherein the fluoropolymer is applied to both sides or one side of the woven fabric. It is cloth.

The fluoropolymer of the present invention has a light transmittance of 80% or more and an oxygen transmission coefficient of 10 when formed into a film.
cc / mil / 100 in ² , 24 hr / atm or less,
It has the characteristics of moisture permeability of 5 g / m ² · 24 hr · 0.1 mm or less. Due to the synergistic effect of these properties and the ultraviolet absorber, the polarizing woven fabric is excellent in durability against high temperature, high humidity, ultraviolet rays, etc. while maintaining the polarizing properties, and is also excellent in antifouling property and chemical resistance.

When the light transmittance is less than 80%, the polarizing woven fabric has a reduced polarization functionality, and the oxygen transmittance is 10 cc.
-If it exceeds mil / 100 in ² · 24 hr · atm, the dye contained in the fiber constituting the polarizing woven fabric described later is easily oxidized by oxygen, and further, the moisture permeability is 5 g / m ² · 24 hr · When it exceeds 0.1 mm, the deterioration of the dye due to moisture increases. In the present invention, the protective transparent resin layer of the polarizing woven fabric satisfies 90% by satisfying the above light transmittance, oxygen transmittance and moisture permeability.
The excellent polarization performance at the initial stage can be maintained even under high temperature and high humidity conditions of 95 ° C. and 95% RH, and the polarization performance can be maintained even when exposed to ultraviolet rays for a long time. In the present invention, the physical properties of such a fluoropolymer are those of a film of the polymer having a thickness of 40 μm.

Examples of such fluoropolymers include polyvinylfluoride resin (PVF), polyvinylidene fluoride resin (PVDF), trifluoromonochloroethylene-vinyl ether alternating copolymer resin (FEV) and poly Chlorotrifluoroethylene (PCT
FE), tetrafluoroethylene / hexafluoroethylene / perfluoroalkoxyethylene copolymer (EPE), and the like, but PCTFE, PVDF, which has a small contact angle with water due to the adhesiveness with the polarizing film. PV
F is preferable, and PVF is particularly preferable in terms of antifouling property, moisture permeability, and oxygen permeability.

Further, it is preferable that such a fluoropolymer is subjected to a hydrophilic treatment from the viewpoint of adhesiveness to the polarizing woven fabric.
The hydrophilic treatment can be performed by an oxygen plasma method, a corona discharge treatment, or the like.

In the present invention, it is necessary that the above fluoropolymer contains an ultraviolet absorber. Such an ultraviolet absorber is not limited to any kind as long as it is a usual ultraviolet absorber, but it is preferable that it does not deviate the light transmittance of the fluoropolymer film, specifically 2,4-di- t-butylphenyl-3 ', 5'-di-t
Benzophenone compounds such as -butyl-4'hydroxybenzoate and 2,4-dihydroxybenzophenone
2- (2'-hydroxy-5'-t-octylphenyl) benzotriazole, 2- (2'-hydroxy-
Examples thereof include benzotriazole compounds such as 5'-methylphenyl) benzotriazole, phenyl salicylate compounds, and the like.

The content of the ultraviolet absorber is preferably 0.1 to 5.0% by weight with respect to the fluoropolymer, and is 0.1 to 0.5% by weight from the viewpoint of light transmittance and polarization performance. More preferable.

Polyvinyl alcohol and ethylene-vinyl alcohol copolymers can be used as the material of the polarizing fibers which compose such a polarizing woven fabric. Of these, ethylene-vinyl alcohol copolymer fibers are easy to obtain a true circular fiber by melt spinning, so when used as a screen material, the projection effect of the projection light due to the lens effect is uniform and the screen viewing angle is large. Not only the characteristics are good, but also there is an advantage that a flexible woven fabric with less yarn unevenness can be prepared, and an inexpensive dichroic direct dye having a high polarization performance can be used as a polarization performance expressing substance. The polarizing woven fabric of the present invention uses the above-mentioned polarizing fiber as at least one of the warp yarn and the weft yarn constituting the woven fabric, and it is preferable that 50% or more of the warp yarn or the weft yarn is the polarizing fiber.

The cross-sectional shape of the polarizing fiber is as described above.
Any cross-sectional shape can be used as long as it can uniformly diffuse light due to the lens effect of the cross-section, but a round cross-section is preferable in view of processability. Further, the fineness of the polarizing fiber is also arbitrary, but in consideration of "eye warp" in which the texture of the woven fabric is deformed, 30 to 200 denier, particularly 50
It is preferably from 150 to 150 denier.

The non-polarizing fiber which constitutes the polarizing woven fabric of the present invention is not limited in its kind as long as it is colorless and transparent. Specifically, polyamides such as nylon 6 and nylon 66,
Fibers such as polyester and polyolefin can be mentioned. The fineness of the non-polarizing fiber is not particularly limited, but is preferably smaller than the fineness of the polarizing fiber in order to increase the woven density of the woven fabric. Further, the cross-sectional shape of the non-polarizing fiber may be any cross-sectional shape that allows uniform light diffusion due to the lens effect of the cross-section, but a round cross-section is preferable in view of processability. .

The polarizing woven fabric of the present invention comprises polarizing fibers and non-polarizing fibers, and these fibers may be monofilaments, multifilaments, or a mixture of both.
A monofilament is preferable in terms of good polarization performance.

The polarizing woven fabric of the present invention can be obtained by coating the above fluorinated polymer on the above woven fabric or by making a woven fabric with polarizing fibers coated with the above fluorinated polymer. . First, a method of coating a woven fabric will be described. A solution obtained by dissolving a fluorine-containing polymer containing an ultraviolet absorber in a ketone, an ester, a chlorine-containing hydrocarbon compound, an amide compound, an alcohol, an aromatic compound or the like is uniformly cast on a woven cloth, or the solution. Dip the woven cloth in and dry. The coating thickness of the fluoropolymer after drying is 1 to 300 μm in consideration of the winding property, workability, handling property of the woven fabric,
Particularly, 3 to 100 μm is preferable. In order to improve the adhesion between the woven cloth and the fluoropolymer, a conventional transparent protective layer, for example, a transparent resin layer such as polyurethane resin or polyester resin is applied to the woven cloth, and then the transparent resin layer is coated with the fluororesin. A polymer may be applied.

Next, a method of coating the polarizing fiber with a fluororesin will be described. Similarly to the method of coating a woven fabric, the fiber is immersed in a solution of a fluoropolymer,
A drying process is performed to form a coating layer. The coating thickness is from 1 to 200 μm, particularly from 3 to 50 μm in the production of the woven fabric in the next step.
m is preferred. Further, in order to improve the adhesion between the fiber and the fluoropolymer, a coating treatment may be performed with, for example, a polyurethane resin or a polyester resin, and then a coating treatment with a fluoropolymer may be performed.

As described above, the polarizing woven fabric coated with the fluoropolymer does not deteriorate due to the synergistic action of heat, humidity and ultraviolet rays, and is kept outdoors (for automobiles for a long time while maintaining the polarization performance). It can be used in the car).

[0018]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. In the examples, "%" means% by weight unless otherwise specified. Each evaluation in the examples is a value measured by the following method. (1) Evaluation of discoloration (ΔE) The sample was irradiated with ultraviolet rays using an ultraviolet irradiation device, and the discoloration was evaluated with a portable spectral color difference meter (NF-90 type, manufactured by Nippon Denshoku Industries Co., Ltd.). UV irradiation device: EYE Super UV Tester (SUV-W type, manufactured by Dainippon Plastic Industries Co., Ltd.) UV irradiation condition: Wavelength range 295 to 450 nm Black panel temperature 45 ° C Humidity 70% RH output 50 mW / cm ² ΔE = [(L ^{_{1 -L 0) 2 + (a}} 1 -a 0) 2 + (b 1
-B ₀ ) ² ] ^1/2 L ₁ , a ₁ , b ₁ : Measured value after UV irradiation L ₀ , a ₀ , b ₀ : Measured value before UV irradiation [The larger the L value, the higher the brightness, a The greater the (+) value, the greater the degree of red, the greater the value of a (-), the greater the degree of green, the greater the value of b (+), the greater the degree of yellow, and the greater the value of b (-), the more blue. Indicates that the degree of is large. Value of ΔE Sensory evaluation content of fading property 0 to 0.5 Slight fading 0.5 to 1.5 Slight fading 1.5 to 3.0 Fading faint 3.0 to 6.0 Fading moderately 6.0 to 12.0 Great fading Greater than 12.0 Great fading

(2) Evaluation of Moisture Resistance The sample was exposed to the conditions of 80 ° C. and 90% RH for 1 week, and the light transmittance and polarization degree of the sample were measured. The light transmittance was measured using a UV spectrometer (manufactured by Shimadzu Corporation), and the degree of polarization was measured using a spectrophotometer (UV-21000 type, using a measuring holder with a polarizer, manufactured by Shimadzu Corporation).

(3) Evaluation of Antifouling Property In the outdoor exposure test, the ΔE value before and after the exposure test was measured using the above-mentioned measuring machine, and the difference was evaluated. Test location: Kurashiki-ku rooftop second floor, 45 ° southward slope location Period: 6 months Evaluation standard △ E difference ◎: 0-1.5 ○: 1.5-3.0 △: 3.0-5.0 × : 5.0 or more

Example 1 Dichroic direct dye (Direct Red 81, Direct Green 85, Dire
ct BLUE 1, manufactured by Sumitomo Chemical Co., Ltd.) was mixed with polyvinyl alcohol to obtain red, blue and green chips. The chips were mixed and wet-spun to obtain a polyvinyl alcohol spun raw yarn.
The spun raw yarn was drawn 7.5 times at 220 ° C. to obtain a fineness of 100.
A denier monofilament was obtained. A transparent resin film made of non-yellowing urethane resin and having a thickness of 10 μm was formed on the monofilament, and then the filament was mixed with 2,4-
Di-t-butylphenyl-3 ', 5'-di-t-butyl-4'hydroxybenzoate (Chemipro Kasei) was added to 0.
A polyvinyl fluoride resin containing 5% by weight was dipped in a solution of dimethylformamide and dried to obtain a thickness of 10 μm.
To form a transparent resin coating layer made of a fluoropolymer having a thickness of. The film made of the fluoropolymer had a light transmittance of 88% and an oxygen transmission coefficient of 3.1 cc · mil / 100.
in ² · 24 hr · atm, water vapor transmission rate 0.6 g / m ² ·
It was 24 hr · 0.1 mm. Using this monofilament as a weft and a nylon 6 monofilament having a fineness of 30 denier as a warp, a warp-polarized woven fabric of three fly sheets with a weft density of 180 filaments / inch and a warp density of 95 filaments / inch was produced. The surface of the woven fabric was mainly exposed to the weft.

The degree of polarization of the obtained woven fabric was 91.1%. In addition, discoloration resistance, moist heat resistance and stain resistance were evaluated, and the results are shown in Table 1.

Example 2 A saponified ethylene-vinyl acetate copolymer having an ethylene content of 47 mol% and a saponification degree of 99 mol% or more was obtained. The dichroic direct dye (Direct Red 81, Direct Green
85, Direct BLUE 1, manufactured by Sumitomo Chemical Co., Ltd.) and then dried to obtain red, blue and green chips. These chips were mixed, melt spun at 195 ° C and 4.7 at 110 ° C.
The filament was drawn twice to obtain a monofilament having a fineness of 100 denier. Using this monofilament, a transparent resin coating of urethane resin having a thickness of 3 μm was prepared in the same manner as in Example 1.
A transparent resin film made of polyvinyl fluoride resin having a thickness of 10 μm was formed. Then, a woven fabric was prepared in the same manner as in Example 1, and the woven fabric was evaluated. Table 1 shows the results.

Example 3 In Example 1, instead of the polyvinyl fluoride resin, 4
Other than using a fluororesin coating material (Lumiflon, manufactured by Asahi Glass Co., Ltd.) based on a fluoroethylene-vinyl ether alternating copolymer containing 0.5% by weight of -t-butylphenyl-salicylate In the same manner, polyvinyl alcohol monofilament was obtained and a woven fabric was prepared. The obtained woven fabric was evaluated and the results are shown in Table 1. The light transmittance of the film made of the fluororesin paint is 9
0%, oxygen permeability coefficient is 6.8cc · mil / 100in
²・ 24hr ・ atm, moisture vapor transmission rate 4.2g / m ²・ 24
It was hr · 0.1 mm.

Example 4 A polarizing fiber made of a saponified ethylene-vinyl acetate copolymer was obtained in the same manner as in Example 2 (fineness: 100 denier).
Le). The polarizing fiber was used as a weft, and a nylon 6 monofilament having a fineness of 30 denier was used as a warp.
A polarized woven fabric of warp satin having 3 yarns / inch and warp density of 95 yarns / inch was produced. The surface of the woven fabric was mainly exposed to the weft. On the surface of this woven fabric, 2,4-di-t
-Butylphenyl-3 ', 5'-di-t-butyl-4'
Fluorine resin containing 0.4% by weight of hydroxybenzoate (Chempro Kasei) (Cytop, Asahi Glass Co., Ltd.)
The solution was applied and dried to form a transparent resin film having a thickness of 10 μm. The degree of polarization of the woven fabric was 91.3%.
The woven fabric was evaluated and the results are shown in Table 1.

Example 5 Polyvinyl alcohol fiber containing iodine (fineness: 10
0 denier) was used to prepare a woven fabric in the same manner as in Example 1. The woven cloth is a fluororesin coating material based on a fluoroethylene-vinyl ether alternating copolymer containing 0.5% by weight of 4-t-butylphenyl-salicylate (Lumiflon, Asahi Glass Co., Ltd.). Manufactured) to form a transparent resin film having a thickness of 5 μm on both sides of the woven fabric. The degree of polarization of the woven fabric was 95.0%. The woven fabric was evaluated and the results are shown in Table 1.

Comparative Example 1 A woven fabric was prepared in the same manner as in Example 1 except that the transparent resin film made of polyvinyl fluoride resin was not formed. The degree of polarization of the woven fabric was 92.1%. Each evaluation was performed on the woven fabric, and the results are shown in Table 1. The change in the polarization degree before and after the moisture resistance evaluation did not show a large difference from the examples, but the peeling of the coating resin was large, and discoloration occurred in a short time as compared with the examples, and there was no practical use.

Comparative Example 2 A woven fabric was prepared in the same manner as in Example 2 except that the transparent resin film made of polyvinyl fluoride resin was not formed. The degree of polarization of the woven fabric was 91.7%. Each evaluation was performed on the woven fabric, and the results are shown in Table 1. The fading outdoors was extremely short and the peeling of the coating resin was large as compared with the examples.

Comparative Example 3 A woven fabric was prepared in the same manner as in Example 3 except that the transparent resin coating film made of the fluororesin paint was not formed. The degree of polarization of the woven fabric was 92.3%. Each evaluation was performed on the woven fabric, and the results are shown in Table 1. The fading outdoors was extremely short and the peeling of the coating resin was large as compared with the examples.

Comparative Example 4 A woven fabric was prepared in the same manner as in Example 4, except that the transparent resin coating film made of a fluorine-based resin was not formed. The degree of polarization of the woven fabric was 91.9%. Each evaluation was performed on the woven fabric, and the results are shown in Table 1. There was a large difference in the degree of polarization before and after the evaluation of moisture resistance, and discoloration occurred in a short time as compared with the examples, and there was no practical use.

[0031]

[Table 1]

[0032]

EFFECTS OF THE INVENTION According to the present invention, there is no deterioration of the woven fabric due to the synergistic action of heat, humidity and ultraviolet rays, and it is possible to use it outdoors (including the inside of an automobile) for a long time while maintaining the polarization performance. A polarizing woven fabric can be obtained.

Claims (2)

[Claims] 1. A polarizing fiber comprising a polyvinyl alcohol or an ethylene-vinyl alcohol copolymer.
Light transmittance of 80% or more, oxygen permeability coefficient of 10 cc · m
il / 100 in ² · 24 hr · atm or less, moisture permeability of 5 g / m ² · 24 hr · 0.1 mm or less, and a fiber formed by coating with a fluoropolymer containing an ultraviolet absorber, warp or weft A polarizing woven fabric used for at least one of the above. 2. A polarizing woven fabric comprising a polarizing fiber made of polyvinyl alcohol or an ethylene-vinyl alcohol copolymer as at least one of warp and weft, and having a light transmittance of 80% or more and oxygen. Transmission coefficient is 10cc
^{· Mil / 100in 2 · 24hr ·} atm or less, the moisture permeability is less ^{5g / m 2 · 24hr · 0.1mm} , and a fluorine-containing polymer comprising a UV absorber on both sides or one side of the woven Polarized woven fabric that is applied.