JPS58168019A - Manufacture of partially colored polarizing film - Google Patents

Abstract

PURPOSE:To obtain the titled polarizing film having a clear boundary between the colored part and the polarizing part by partially forming a mixture of a nondigenetic dye with a reducing agent and a specified substance on one side of an iodine-contg. polarizing film and treating the film at high temp. and humidity. CONSTITUTION:An aqueous soln. contg. a mixture consisting of a nondigenetic dye such as ''Acid Blue 161'', a reducing agent such as NaOH and a water- soluble or water-swellable substance in which the reducing agent and the dye can be diffused and moved, e.g. starch in (1-3):(8-7):(1-2) weight ratio is partially applied to a prescribed region of one side of an iodine-contg. polarizing film having a support of 25-500mum thickness on the other side so as to adjust the solid matter content to 0.1-20g/m<2>. The polarizing film is then treated at 40-90 deg.C high temp. and 70-98% high relative humidity for 1-60min to reduce iodine molecules in the applied part. The polarizing power of the part is lost, and the nondigenetic dye is allowed to be adsorbed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a partial color polarizing film for a partial color polarizing plate used in liquid crystal display devices and the like.

Liquid crystal display devices using polarizing plates are widely used in hour hands, desktop electronic meters, and the like. Recently, application to automobile instrument panels has been considered as another field. This panel display generally has a black background and displays a white pattern in a specific area by voltage driving the liquid crystal.
The new negative display method is considered to be the mainstream.

This method is achieved by installing polarizing plates above and below the liquid crystal cell, but creating all displays using electrodes is subject to space, design, and technical constraints. Therefore, as a display device, polarizing plates are disposed above and below the liquid crystal cell, but a so-called fixed display method is adopted in which electrodes are not used for the part that is constantly displayed when the display is turned on.

One of the useful methods for forming this fixed display method is to add a portion (non-polarizing ) and then attach a color filter to this portion, or use a partially colored polarizing plate colored by printing or the like.

However, the partial color polarizing plates known so far have been colored by filters or printing as described above.
The interface between the white part and the polarizing part has the disadvantage that the appearance is unsightly because a gap or a conductive part is formed, and the coloring is complicated to operate.

The present invention provides a novel method for producing a partially color polarizing film that overcomes the drawbacks of the prior art, and its gist is that a carrier is formed on one side of an iodine-based polarizing film, and a carrier is formed on the other side of the iodine polarizing film. A mixture of a non-dichroic dye, a reducing agent, and a substance in which the reducing agent and the dye can diffuse is partially formed on the surface in a predetermined area, and then subjected to high temperature and high humidity treatment.

To explain the manufacturing method of the present invention more specifically, a non-dichroic dye, a reducing agent, and a substance in which the reducing agent and dye diffuse and move onto the other surface of a polarizing film whose one surface is supported by a carrier. A mixture consisting of the Absorb the reducing agent and non-dichroic dye into the original film whose absorbing ability has been improved by high-temperature and high-humidity treatment, making the entire mixture forming area non-polarizing and adsorbing the non-dichroic dye to that area. It is something.

Polarizing film used in carrying out the present invention
Examples include iodine-based polarizing films in which iodine is adsorbed and oriented on hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene-vinyl acetate copolymer films.

One surface of the polarizing film formed in this manner is coated with a moisture-resistant film such as polyester film, polyacrylic film, or acetate film, in order to prevent the film from collapsing when subjected to high temperature and high humidity processing. (Plastic film or film with excellent heat resistance and transparency)
5 to 500 μm) is formed. When the carrier is used as a surface retainer for the color polarizing film, both sides are attached in a non-removable manner;
If the polarizing film is attached solely for the purpose of preventing shrinkage, it is necessary to design the adhesive force or the attachment method so that it can be peeled off.

Reducing agents used in carrying out the invention include, for example, sodium hydroxide, which has the effect of reducing iodine molecules.
Potassium hydroxide, sodium thiochloride, etc.

The substance supporting the reducing agent is a substance that is water-soluble or water-swellable, allows the reducing agent to diffuse and move, and has a film-forming ability, such as starch, 'carboxymethyl cellulose, and sodium alginate. There are water-soluble polymer substances.

Examples of non-dichroic dyes include Acid Blue 161, Direct Blue 199, Acid Red 220, and Acid Green 57''.

The modifier, substance and non-dichroic dye are in a ratio of 1 to 3:8 to 7.
: 1 to 2 (weight ratio) is mixed to form a water I @ liquid, but if the reducing agent is less than 1, the polarizing film cannot be made sufficiently non-polarizing, and if it is more than 3, it is not economical. In addition, the reducing agent spreads from the coated portion, making it impossible to obtain a beautiful interface between the polarized light portion and the non-polarized light portion, which is undesirable.

The mixture constituted in this manner is partially applied to a cover cloth (solid content: 0.00% in solid content) in a desired pattern in a predetermined area in the exposure direction of the standard film (Ii where no carrier is formed).
1-209. /d), 40-b70-98% F+,
1! , Xi to 60 minutes, preferably 6° to 80°C x 90
~98cm R0H0x1~By performing high temperature and high humidity treatment in the range of 60 minutes, the area to which the mixture was applied was treated. 9. : This is a book that removes the polarizing property of this part by reducing starving molecules, adsorbs non-dichroic dye, and obtains a partially colored polarizing film by drying with water. If the processing diameter is less than 40°C x 70mm R,H, the processing time will be longer and it is less practical, and if it is above 95°C x 98SR,H, the polarizing ability of the polarizing film will be inhibited, so it is not suitable. It is something. In addition to exposing the polarizing film to the above-mentioned atmosphere, the high-temperature seed treatment can also be performed by exposing the polarizing film to a hot water vapor of 1k1m.

The partial color original film obtained in this way has one surface on one side and one surface on both sides! As lk-, a plastic film having optical A brightness or the like is layered to form a partial color polarizing plate. When the above-mentioned carrier is used as a general surface preservation layer, a surface preservation layer is further formed on the it% or non-formed surface to obtain a partial color polarizing plate.

As described above, the manufacturing method of the present invention involves partially applying a mixture containing a reducing agent and a non-dichroic dye to the surface of a polarizing film and subjecting it to high temperature and high humidity treatment, so that the polarization of the applied area is completely maintained. It is characterized in that it is colored at the same time as it is removed, the boundary between the colored part and the polarized part is clear, and it can be colored with a simple operation.

Below) Examples of the present invention are shown. In the sentence - means 1 [electric punch.

Example 4 A triacetate film with a thickness of 70 μm was laminated on one side of an iodine-based light-dispersing film having a light transmittance of 2%, and 1% sodium thioserate was applied on the other side.

Sodium Alginate 5- and 1% Acid Blue 161
A uniformly dissolved water-soluble iris is printed in a pattern,
Treated at 60℃ x 95% R, H, X for 15 minutes at high temperature and high humidity, washed with water to remove sodium alginate, and heated at 70℃ for 10 minutes.
After drying for minutes, a partially colored polarizing film was obtained.

Most of the part of this film coated with the aqueous solution has polarizing properties and C
Instead, it was colored blue, and the boundary between the colored part and the polarized part was beautifully formed in a straight line shape.

IJf! f permit applicant Nihon Applicant Industry Co., Ltd. Representative Sanbe Hijikata

Claims (1)

[Claims] A carrier is formed on one side of the FK yarn polarizing film, and a mixture of a non-dichroic dye, a reducing agent, and a substance to which the reducing agent and dye can diffuse is partially applied to a predetermined area on the other side. A method for producing a partially colored polarizing film, which is characterized by forming the film into a film and subjecting it to high-temperature, high-humidity treatment.