JPH0153447B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image forming method used for manufacturing printed wiring boards, lithographic printing plates, etc.

Conventionally, as such an image forming method, a method in which a water-soluble polyvinyl alcohol resin is laminated as a support layer on the surface of a photosensitive layer is known (Japanese Patent Application Laid-Open No. 140341/1989, etc.).
This makes it possible to dissolve and remove the support layer with water or an aqueous alkaline solution without peeling it off during development, and furthermore, development can be performed simultaneously, so the water-insoluble resin film can be used as both the support layer and the support layer. This has the advantage that it is easier to automate the work than if you were to do it yourself.

However, it has been found that with this method, polyvinyl alcohol resin is inevitably contained in the water after dissolution, and there is a problem in its disposal.

Initially, the dissolution water has a low concentration of polyvinyl alcohol resin, so it can be recycled, but when the concentration reaches a high concentration of about 3 to 5%, the dissolution rate for the polyvinyl alcohol resin decreases significantly, and It is easy to foam during liquid circulation, which may have a negative impact on work efficiency, and on the other hand, since the concentration of polyvinyl alcohol resin is low from such a dilute solution, it is possible to recycle it, but if the concentration is 3.
If the concentration is as high as ~5%, the dissolution rate for polyvinyl alcohol resin will drop significantly, and it may cause foaming during liquid circulation, which may have a negative impact on work efficiency. Concentration and removal is too economical.

As a result of repeated studies to solve these problems, the present inventors have discovered that a laminate in which a water-soluble polyvinyl alcohol resin layer (A) and a photosensitive layer (B) are laminated is made such that (B) contacts the substrate. After polymerization and exposure through (A), (A) is brought into contact with an aqueous solution of an inorganic salt that has coagulant power against water-soluble polyvinyl alcohol resin to disperse and remove it, and then (B) They have discovered that the problem can be solved by a developing method, and have completed the present invention.

That is, in the present invention, when removing the water-soluble polyvinyl alcohol resin layer that is the support layer, instead of the conventional method of dissolving it with water or an alkaline aqueous solution, an inorganic resin having a coagulant ability with respect to the polyvinyl alcohol resin is removed. It is characterized in that it is brought into contact with an aqueous salt solution, whereby the polyvinyl alcohol resin layer swells in a short period of time without being dissolved at all, and is dispersed and removed from layer (B) in the form of a film or small pieces. It is.

The polyvinyl alcohol resin and water can be easily separated by passing the liquid containing the dispersion of polyvinyl alcohol resin film pieces through a coarse wire mesh, etc., so that the water in which the polyvinyl alcohol resin has been dissolved can be treated. This is extremely advantageous in practice compared to the case where Moreover, even with this method, the removal rate of the polyvinyl alcohol resin layer is comparable to that of the conventional dissolution removal method, and the subsequent development process is not adversely affected at all.

The water-soluble polyvinyl alcohol resin used in the present invention may be any polyvinyl alcohol that is essentially soluble in hot water at room temperature or about 70°C, for example, an average degree of polymerization of 200 to 3000 and a degree of saponification of 50 to 100 mol%. , preferably average degree of polymerization 500~
Polyvinyl alcohol having a saponification degree of 80 to 99 mol% is suitable. Furthermore, saponified copolymers of various modified polyvinyl alcohols or vinyl acetate within the range of water solubility as described above may be used.
The former includes acetalized products and acetoacetylated products such as formalin, acetaldehyde, butyraldehyde, glyoxal, and glutaraldehyde, while the latter includes unsaturated products such as (meth)acrylic acid, crotonic acid, (anhydrous) maleic acid, and itaconic acid. Examples include saponified copolymers of vinyl acetate and small amounts of carboxylic acids, their esters, α-olefins such as ethylene and propylene, (meth)allylsulfonates, acrylamide, methylolacrylamide, and N-vinylpyrrolidone. . Moreover, not only these water-soluble polyvinyl alcohol resins may be used alone, but also small amounts of starch, cellulose derivatives, casein, etc. may be mixed with them.

The photosensitive layer is not particularly limited, and any of the known alkali aqueous solution development type and solvent development type can be used.

In the present invention, a laminate of a water-soluble polyvinyl alcohol resin layer (A) and a photosensitive layer (B) as a support layer may be used. It also includes the case where it is used as a layered product and the C layer is peeled off. As the C layer, polyethylene, polypropylene, polyester, etc. are used.

The thickness of the photosensitive laminate is usually 5 to 100μ for layer A.
Preferably, the thickness is selected from the range of 10 to 30μ, and the B layer is selected from the range of 5 to 100μ, preferably 10 to 70μ.

A photosensitive layer consisting of A and B is stacked so that the B layer is in contact with a substrate made of copper, aluminum, polyamide, etc., and bonded under pressure. Bonding is usually done using a heated roll. A photographic member is then placed over layer A and exposed to active light, such as ultraviolet light.

Examples of inorganic salts that have coagulability for water-soluble polyvinyl alcohol-based resins include ammonium sulfate,
Sodium sulfate, potassium sulfate, magnesium sulfate, zinc sulfate, copper sulfate, iron sulfate, aluminum sulfate, potassium aluminum sulfate, ammonium nitrate, sodium nitrate, potassium nitrate, aluminum nitrate, sodium chloride, potassium chloride, magnesium chloride, calcium chloride, hydrogen carbonate Examples include sodium, boric acid, borax, etc., and aqueous solutions of these alone or in combination are used. The optimal range of inorganic salt concentration should be determined depending on the coagulation power of each inorganic salt. Dilute aqueous solutions will dissolve the polyvinyl alcohol resin and will not achieve the desired effect, while extremely concentrated aqueous solutions will not achieve the desired effect. Since dispersion and removal becomes difficult, a range of about 0.1 to 20% is usually desirable. In addition, when a surfactant such as sulfosuccinic acid ester is used in addition to the above-mentioned inorganic salt, the permeation rate of the liquid increases and dispersion and removal becomes possible in a short time. The temperature of the inorganic salt aqueous solution is 5 to 50
The temperature is preferably selected from a range of about 15 to 40°C. Methods for bringing the layer into contact with the inorganic salt aqueous solution include immersing the laminate in the inorganic salt aqueous solution, and applying vibration, ultrasonic waves, or high frequency to the laminate at that time. Any method can be adopted, such as the method of injecting the

After layer (A) is dispersed and removed, layer (B) is developed. Development is performed with an aqueous alkaline solution such as an aqueous sodium carbonate solution or a sodium tripolyphosphate solution, or with an organic solvent such as trichloroethane, depending on the type of layer (B).

Furthermore, after development, etching, solder plating, etc. of the substrate are performed as necessary.

Next, the present invention will be specifically explained with reference to Examples.

Example 1 Layer A: 100 parts of polyvinyl alcohol (degree of polymerization 1400, degree of saponification 96%), dipropylene glycol 3
An aqueous polyvinyl alcohol film having a thickness of 25 μm was obtained by drooling an aqueous solution consisting of 400 parts and 400 parts of water.

B layer: Alkali-soluble acrylic copolymer photosensitive resin A methyl ethyl ketone solution of B is applied on a 25μ thick polyethylene terephthalate film (C) using a roll coater, dried, and the thickness of B after drying is
A 50 μm laminate was obtained, and then the above film A was pressed onto the B layer using a hot roll to obtain an A/B/C three-layer laminate.

While layer C was peeled off from the three-layer laminate, layer B was thermocompression-bonded onto the copper-clad laminate so that it was in contact with it, and then a patterned mask film was placed on layer A and exposed using an exposure machine.

Thereafter, without peeling the A layer, apply a 5% sodium sulfate aqueous solution (liquid temperature 35°C) to the surface of the A layer of the laminate.
°C) from a nozzle with a diameter of 1.5 mm at a discharge pressure of 1 Kg/cm ² ,
Sprayed for 1 minute at a distance of 12 cm from the nozzle.

Layer A was immediately swollen and removed and floated in an aqueous sodium sulfate solution, which could be easily removed by filtering through a wire mesh. Polyvinyl alcohol was not dissolved in the sodium sulfate aqueous solution. A
The photosensitive layer laminate from which the layers had been dispersed and removed was developed with a 1.3% aqueous sodium carbonate solution. Images with high resolution and good through-hole tenting strength were obtained.

Example 2 Layer A Polyvinyl alcohol (degree of polymerization 1800, degree of saponification 88 mol%) 70 parts Polyvinyl alcohol (degree of polymerization 1400, degree of saponification 96 mol%) 30 parts cornstarch 8 parts glycerin 1 part dipropylene glycol 1 part water 450 A water-soluble polyvinyl alcohol film with a thickness of 25 μm was obtained by sulfur rolling an aqueous solution consisting of

A photosensitive laminate was produced in the same manner except that the layer A described above was used in place of the layer A in Example 1, and exposed using an exposure machine.

After that, without peeling off the A layer, apply an 8% concentration sodium sulfate aqueous solution (liquid temperature 35
°C) from a nozzle with a diameter of 1.2 mm at a discharge pressure of 1 Kg/cm ² ,
It was sprayed for 1 minute at a distance of 10 cm from the nozzle.

Layer A immediately swelled and became small pieces and dispersed in the aqueous sodium sulfate solution. This could be easily removed by passing it through a wire mesh. Polyvinyl alcohol was not dissolved in the sodium sulfate aqueous solution. Next, development was carried out with an aqueous solution of sodium carbonate, but no problems were observed.

Example 3 Using a sodium bicarbonate aqueous solution with a concentration of 8% instead of the sodium sulfate aqueous solution in Example 1,
As a result of the same experiment except that the injection time was changed to 45 seconds, the A layer swelled immediately and was completely removed.

Example 4 Layer A An aqueous solution consisting of 100 parts of polyvinyl alcohol (degree of polymerization: 1800, degree of saponification: 99 mol%), 1.5 parts of glycerin, 1.5 parts of dipropylene glycol, and 500 parts of water was formed by drooling to obtain a film with a thickness of 25 μm.

The experiment was conducted in the same manner as in Example 1, except that the above A layer was used instead of the A layer, and a 1% sodium sulfate aqueous solution was used instead of the 5% sodium sulfate aqueous solution. As a result, the A layer swelled immediately. and was completely removed.

Example 5 Layer A Same as in Example 2 Layer B Trichlene soluble acrylic copolymer photosensitive resin C layer Polyethylene terephthalate (thickness 25μ)
and polypropylene (thickness: 25 μm) A photosensitive resin (methyl ethyl ketone solution) for layer B is applied on the polypropylene surface of layer C using a roll coater (thickness of layer B after drying is 25 μm), and then layer A is applied on top of it. The layers were pressed together with a hot roll to obtain an A/B/C three-layer laminate.

While layer C was peeled off from the three-layer laminate, layer B was thermocompression-bonded onto the copper-clad laminate so that it was in contact with it, and then a patterned mask film was placed on layer A and exposed using an exposure machine.

After that, an ammonium sulfate aqueous solution with a concentration of 8% (liquid temperature
35°C) was sprayed from the nozzle for 1 minute.

Layer A immediately swelled and was dispersed and removed in small pieces. The B layer side was then washed with a water spray, dried with an air spray, and then developed with 1,1,1-trichloroethane. Good images with high resolution were obtained.

Example 6 As layer A, an aqueous solution consisting of 100 parts of polyvinyl alcohol with a degree of polymerization of 1200 and a degree of saponification of 92 mol%, 3 parts of glycerin, and 400 parts of water was formed into a film with a thickness of 27 μm.
I got this film. Then, a methanol solution of glyoxal was sprayed onto one side of the film at a temperature of 40°C and dried.

A photosensitive layer laminate was prepared in the same manner as in Example 1 except that the above glyoxalated polyvinyl alcohol film was used in place of the water-soluble polyvinyl alcohol film (A) in Example 1. A 1% aqueous sodium sulfate solution (temperature: 35° C.) was sprayed onto the photosensitive laminate at a discharge pressure of 1 Kg/cm ² and at a distance of 12 cm from the nozzle. Within 1 minute after the start of injection, layer A is 0.5 to 5 mm per side.
It was dispersed and removed in small pieces.

Claims (1)

[Claims] 1 A laminate consisting of a water-soluble polyvinyl alcohol resin layer (A) and a photosensitive layer (B) is polymerized and adhered so that (B) is in contact with the substrate, and after exposing (A) to light, (A) is An image forming method comprising bringing a water-soluble polyvinyl alcohol resin into contact with an aqueous solution of an inorganic salt having coagulating power to disperse and remove the resin, and then developing (B).