JPH0328801A - Manufacture of polarizing film - Google Patents

Abstract

PURPOSE:To manufacture a simple polarizing film in small man-hours by using simple facilities by loading a vinyl resin film after uniaxial drawing processing in a sublimed dichroic coloring matter solvent. CONSTITUTION:The vinyl resin film 1 after the uniaxial drawing processing is charged in a sealed container 4 where the sublimed dichroic coloring matter solution is injected, and then sublimed dichroic coloring matter is adsorbed by the vinyl resin film 1. Therefor, the adsorbed dye is dichroic, i.e. has linearly long molecule structure and an absorption range in the visible light range, and dye molecules are oriented in a constant direction and dyed by drawing a high polymer to provide polarizing operation. Consequently, the film 1 and dye liquid are not brought into contact with each other directly, so neither sampling nor drying is required and this method is suitable for partial dyeing using resist.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for producing a polarizing film using, for example, a PVA film.

<Prior Art> Conventional methods for producing polarizing films include the following various methods. For example, by soaking a PVA (polyvinyl acetate) film in a dichroic dye (iodine) solution,
The dye was adsorbed onto the VA film.

There is also a method in which a PVA film is immersed in a dichroic dye solution, the dye is adsorbed onto the film, and then the film is uniaxially stretched.

There is also a method of manufacturing a polarizing film by coating a dichroic dye on a film and then rubbing the coated surface with cotton or the like.

Furthermore, there is a method in which a sublimable dichroic dye provided on a carrier is sublimated by heating and adsorbed onto a film.

<Problems to be Solved by the Invention> However, according to the first method, it is necessary to wipe off the solution from the soaked film and dry it. Further, even in the second method, wiping off the solution and drying steps are necessary, resulting in a large number of steps, and furthermore, it was only possible to produce a film that had polarizing properties over the entire surface. In general, even the third method involves a large number of steps, and
There was a problem that only a film with a small degree of polarization (50 to 70%) could be obtained. The fourth method requires a carrier, and there is a problem in that if the dye is not uniformly provided on the carrier, uneven adsorption will occur.

Therefore, an object of the present invention is to provide a method for manufacturing a polarizing film using simple equipment and a small number of steps.

Means for Solving the Problems> In the method for producing a polarizing film according to the present invention, K-vinyl is subjected to uniaxial stretching treatment in a closed container filled with a sublimable dichroic dye solution, such as an iodine solution. resin film,
For example, this is a method for producing a polarizing film in which a sublimable dichroic dye is adsorbed onto the vinyl resin film by charging the PVA film.

Effect> In the method for producing a polarizing film according to the present invention, an iodine solution, for example, 500 c of water, is added at room temperature (or under heating).
Stock solution 1 consisting of c, 6 g of iodine, and 15 g of potassium iodide
A solution prepared by diluting 00 cc with 30 cc of water is placed in a closed container. As a result, the airtight container is filled with iodine gas and water vapor.

Then, in this airtight container, PV that has been subjected to uniaxial stretching treatment is placed.
A film, for example, a 3% boric acid aqueous solution was heated to 40°C, a highly saponified PVA film (thickness 200 μm) with a degree of saponification of 99% was immersed for about 3 minutes, and then stretched at a stretching rate of 300%. or a transparent base material with the PVA film attached thereto.

As a result, a large number of iodine molecules are aligned and adsorbed in the helical structure of PVA. In other words, a reaction that produces one-dimensional multi-iodine molecules occurs. By holding the container in the atmosphere for a certain period of time, a suitably dyed film is taken out. In addition, as for the heat treatment while being left in an atmosphere, by keeping the whole at about 60° C., a sufficient degree of polarization can be obtained in a shorter time (for example, about half a day) than when left at room temperature. Alternatively, the reaction can be similarly accelerated by heating only the bath to 60 to 80°C.

This one-dimensional multi-iodine production reaction is well known as the iodine starch reaction.
When iodine molecules come into contact with each other, a large number of iodine molecules are adsorbed in a line in a long tunnel formed in the long, thin helical structure of the polymer.

Here, PVA alone has a poor quality structure with a weak helical structure, and the iodine molecules once adsorbed are quickly desorbed. Therefore, by uniaxially stretching PVA in an aqueous boric acid solution, a film with a fixed structure in which tunnels are oriented in one direction is obtained. By the boric acid treatment, some of the OH groups of PVA are converted to B of boric acid.
It reacts with O43- ions to form a network structure and becomes a water-insoluble PVA polymer. Furthermore, by performing the stretching process at the same time, the polymer chains are oriented in the stretching direction, and the tunnels are aligned in a certain direction. FIG. 1 shows this state as a model.

In the film produced as described above, the adsorbed dye exhibits dichroism, that is, it has a one-dimensionally long molecular structure and has an absorption range in the visible light region. Furthermore, it exhibits a polarizing effect because the dye molecules are oriented in a certain direction due to polymer stretching or the like.

<Example> Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows the structure of the PVA film used in this example. Moreover, FIG. 3 shows the state of the reaction vessel and film of this example.

The film 1 used was a triacetate film 2 made by uniaxially stretching two PVA films 11 and 12 in a boric acid aqueous solution so that their stretching axes were perpendicular to each other.
, 2 as a reinforcing material and laminated as shown in FIG.

Note that the center portion in the figure is the adhesive layer 3.

A right negative image and a left negative image of the negative image photographed for stereo printing are printed with transparent ink on the front and back sides of the films 11 and 12, respectively.

Then, as shown in FIG. 3, a glass container 4 is prepared, and a stainless steel vat (pallet) 5 is installed at the bottom of the container. This vat 5 contains 100 c of iodine solution for dyeing.
Enter c. This iodine solution consists of 500cc of water and 68 iodine.
, 100 cc of a stock solution consisting of 15 g of potassium iodide was mixed with 3 ml of water.
It was diluted with 0cc.

Here, the PVA film 1 prepared in advance as described above is suspended in this glass container 4. In this case, a curl prevention frame is attached to the film 1 if necessary. Leave it in this state for 2 to 3 days. As a result, only the areas without transparent ink are dyed, and a 3D image is created.

Effect> As explained above, according to the present invention, the film and the dyeing solution do not come into direct contact with each other, so there is no need for wiping or drying. It is also suitable for partial staining using a resist.

[Brief explanation of drawings]

FIG. 1 is a model diagram showing the molecular structure of a PVA film according to the present invention, FIG. 2 is a cross-sectional view of a PVA film according to an embodiment of the present invention, and FIG. 3 is a schematic perspective view showing an apparatus according to an embodiment. It is a diagram. 1●・◆・・・・・・PVA film, 4・・・・・・
...Glass container.

Claims (1)

[Claims] By charging a vinyl resin film that has been subjected to a uniaxial stretching process into a closed container filled with a sublimable dichroic dye solution, the sublimable dichroic dye is adsorbed onto the vinyl resin film. A method for producing a polarizing film characterized by: