JPS6142038B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for dyeing hydroxymethacrylate resin or a resin containing it as a main monomer component.

Hydroxy methacrylate resin is characterized as a resin that is insoluble in water due to its molecular structure having hydroxyl groups, but has extremely excellent hygroscopicity and water-swellability. Since then, this resin has been processed into films, membranes, molded products, etc., and several applied products that take advantage of this property have been developed. These can be dyed depending on the purpose, or can be colored with letters, etc.
Naturally, it becomes necessary to print images such as patterns. However, due to the characteristics of this resin, it is used in an atmosphere of water or steam, so printing with normal oil-based ink is impossible, and even if it is possible to print and dye using water-based ink or dyeing liquid, Because the resin swells with water, the image is not dyed and is eluted.

To give an example that has been attempted in the past, for example, when hydroxy methacrylate resin is brought into contact with a water-soluble dye solution, it is easily dyed and a clear image is obtained, but if it is kept in water for a long time, the dye gradually dissolves and the image becomes blurred. disappears. In addition, if you print on the surface of this resin product with general ink made by dissolving and dispersing dyes, pigments, binder resin, etc. in an oil-based solvent, you may be able to print clearly temporarily, but if you keep it in water for a long time, the ink will deteriorate. The adhesive strength weakens and the printed image gradually becomes fainter. As shown in the above examples, it is clear that when printing and dyeing hydroxy methacrylate resin products, the commonly thought of methods that utilize the adhesive strength of ink or methods that simply dye the resin are inappropriate. Summer.

The present invention was achieved as a result of intensive research in consideration of this point, and its gist is to provide a method for dyeing hydroxyethyl methacrylate or a resin containing this as a main monomer component. A dyeing method characterized by infiltrating a desired part with a water-soluble vat dye leuco substance having photosensitivity, and then exposing the resin with light absorbed by the water-soluble vat dye leuco substance having photosensitivity. This is an extremely effective method that theoretically eliminates the drawbacks of the conventional method.The water insolubilization treatment, which is the basis of this invention, allows the dye to become entangled within the polymer network structure of the resin, and even if the resin is swollen with water. An extremely stable dyed image can be formed without running out.

Next, the present invention will be explained in more detail.

First, water-soluble butt dye leuco body,
As is well known, this dye reduces butt dye,
It is a water-soluble compound in the form of a sulfonate, and as it is, it is a colorless leuco compound.

Some of the water-soluble butt dye leuco bodies include dyes that cause a photooxidation reaction. Examples of such photosensitive water-soluble Vat dye leuco bodies include Solubilised Vat yellow 3, 4, 7, 8,
Red1, 2, 10, Blue2, 5, 8, Black1, 4, 6
etc.

When a dye solution or ink containing this dye is brought into contact with the resin, the dye penetrates into the resin due to its affinity. When this resin is then exposed to light that is absorbed by the dye that has permeated therein, water-insoluble and color-forming reactions of the dye occur within the resin, forming an extremely stable image. In addition to this dye, stabilizers and additives that improve printability are appropriately added to the water to make a dyeing solution or ink.

Examples will be described below.

Example 1 A transparent film made of 2-hydroxyethyl methacrylate resin was coated with a water-soluble butt dye Anthorazole 04G (manufactured by Hoechst) aqueous solution (concentration 30).
g/) for 10 minutes (pre-soaking), take it out, remove the solution adhering to the surface, and add Be'sulfuric acid (concentration approximately 10 c.c./) and sodium nitrite (concentration approximately 0.5 g/ ) in water (coloring bath).
After soaking for a minute, the film was uniformly dyed blue. Thereafter, the film was thoroughly washed with water to remove unreacted dye.

When an image was projected onto this transparent film from a 2kW mercury lamp through a transparent original, a clear blue image was formed. Thereafter, this film was sufficiently boiled in hot water to dissolve the dye in the non-image area. In order to examine the dyeing properties of the film dyed using this method, the film was boiled in boiling water for several hours (fastness test), and it was confirmed that the color did not fade and the dyeing was strong. . In addition, when dyeing was carried out in the same manner using other photosensitive water-soluble butt dye leuco bodies, almost the same results were obtained.

Example 2 A soft contact lens processed from cross-linked 2-hydroxyethyl methacrylate resin was immersed in physiological saline to swell. After taking out this lens and removing water from the surface, a predetermined position near the periphery of the lens was impregnated with ink consisting of 3 parts of water-soluble butt dye Anthrasol Pink 13B (manufactured by Hoechst), 13 parts of glycerin, and 14 parts of water. Letters were printed using a porous, sponge rubber stamp. Thereafter, when this lens was exposed to black light (light intensity: 2 mW/cm ² ) for about 1 minute, clear red letters appeared. This dyed letter is Example 1
It withstood the same robustness test.

Example 3 An ink having the composition shown in Example 2 was applied to a predetermined portion near the periphery of the lens shown in Example 2. Afterwards, a 2kW mercury lamp was used to project a character image through a transparent negative manuscript onto the coated area for about 2 minutes, and a clear red color appeared. The lens was then immersed in hot water, and the uncolored dye was eluted from within the lens. The dyed letters thus formed satisfactorily withstood the same fastness test as in Example 1.

In Examples 2 and 3, similar results were obtained even when other photosensitive water-soluble butt dye leuco bodies were used.

Claims (1)

[Scope of Claims] 1. In a method for dyeing hydroxyethyl methacrylate or a resin containing hydroxyethyl methacrylate as a main monomer component, after impregnating a desired portion of the resin with a photosensitive water-soluble butt dye leuco compound, A dyeing method comprising exposing the resin to light that is absorbed by the photosensitive water-soluble butt dye leuco body. 2. In claim 1, after infiltrating a desired position of a soft contact lens made of hydroxy methacrylate resin with an ink containing a photosensitive water-soluble butt dye leuco body, the lens is coated with the photosensitive material. 1. A dyeing method comprising exposing to light absorbed by a water-soluble butt dye leuco body.