JPH024255A - Photosensitive resin composition - Google Patents

Abstract

PURPOSE:To enable development with an aq. developing agent and to retain water resistance of a photopolymerized product by using a photosensitive resin compsn. contg. an ethylenic unsatd. compd. which is polymerizable by active rays, a high molecular compd., and a photopolymn. initiator, and adjusting a softening point of the compsn. to a specified value. CONSTITUTION:The title photosensitive resin compsn. contains an ethylenic unsatd. compd. which is polymerizable by active rays, a high molecular compd. which is mechanically miscible with said ethylenic unsatd. compd., and a photopolymn. initiator capable of generating active species by the active rays. A softening point of the compsn. is adjusted to 45-80 deg.C. The compsn. is solid at room temp. but acquires fluidity at high temp. due to decrease of the viscosity. Aqueous development is possible and a photosensitive resin compsn. having high water resistance and alcohol resistance is obtd. since development capacity is imparted to a hydrophobic component thereof.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a photosensitive resin composition that can be developed with hot water or hot water containing a surfactant, and is widely used in photosensitive image forming materials such as photoresist materials. This invention relates to a photosensitive resin composition that can be used not only for relief printing materials such as flexo printing materials, but also for wide (Murayama materials) and the like.

(Prior Art) A large number of photosensitive resin compositions have been reported in the past. These can be classified into two types based on their form and development method.

The liquid resin component is turned into a solid state by photoreaction, and the liquid resin in the non-exposed area is removed as it is or is removed by a developer. The other type is one in which the solid B resin composition is photopolymerized by a photoreaction, and the solid resin in the non-exposed area is swollen and dispersed by a developer and removed.

A known example in which the liquid resin is cured by photopolymerization and the liquid resin component in the unexposed area is removed is, for example, Japanese Patent Publication No. 49-88.
610, JP-A No. 49-075860, etc., related to photosensitive resin letterpress materials, J, Appl, Poly
a+, Sc1.2. 302. 308 (1959) regarding photoresist materials.

Those in which the solid state resin is photopolymerized by a photoreaction and the solid state resin in the non-exposed area is swollen and dispersed by a developer and removed can be further divided into two types depending on the type of developer.
One type is developed using organic solvents such as alcohols or halogen-based organic solvents, and the other type is developed using aqueous developing solutions such as alkaline water and neutral water. Many of these have been reported, and the following are known examples. That is, USP No. 3,024.180 and USP No. 3,874 as halogen-based organic solvent developable ones.
．． No. 486, JP-A-58-8201, JP-A-58-8
No. 9235, etc., and U as an alcohol-based developing type.
Examples include SP3,801°328 and EP0104751. Also, some of the known examples of alkaline water and aqueous development type products include Japanese Patent Publication No. 4B-28125,
There are Special Publication No. 4B-27483, Special Publication No. 2082 No. 53-1982, etc.

(Problems to be Solved by the Invention) [-] The prior art had the following problems. In other words, systems that photocure liquid resin have the advantage of being able to recover and reuse uncured liquid resin, but the equipment becomes large-scale during exposure, and a large number of spaces are required to maintain thickness accuracy. Even in the case of thin film molding, there are various problems such as thickness accuracy in the coating process. On the other hand, in the case of the current same-width resin, the problems with liquid resin have been largely solved. However, the following problems remain regarding the performance of the developer and resin. Current same-width resins are thicker depending on the developer (they can be divided into two types. One is a type developed with organic solvents including halogenated solvents, and the other is a type developed with an aqueous solvent.

For example, organic solvent development type photopolymerized materials have excellent ink resistance in photosensitive flexographic printing plates, but there are various issues such as environmental regulations regarding developers, impact on the human body, cost, closed system of equipment, etc. contains problems. On the other hand, aqueous development If; 17 is preferable from the viewpoints of ease of post-processing of the developer, availability, cost, environment, influence on the human body, and the like. However, the conventional water-based developing type requires a hydrophilic compound, and therefore has the problem that there is a limit to the water resistance of the photoresist.

The present invention addresses the above-mentioned drawbacks of conventional photosensitive resin compositions, such as various problems such as thickness accuracy in liquid resins, effects on the environment and human body in organic solvent development type, and problems such as closed cost equipment. It is an object of the present invention to provide a solid photosensitive resin composition in which water-based development is possible and the photopolymer has water resistance by solving problems such as the limited water resistance of the photopolymer in the water-based developable type. be.

(Means for Solving the Problems) That is, the present invention provides (an ethylenically unsaturated compound that can be polymerized by Al actinic rays, (B) a polymeric compound that can be mechanically mixed with an Al component, and (C) an ethylenically unsaturated compound that can be polymerized by Al actinic rays). A photosensitive resin composition containing a photopolymerization initiator capable of generating active species, and characterized in that it has a softening point between 45 and 80°C.

Component (A) in the present invention, i.e., for blending the ethylenically unsaturated compound that can be polymerized by actinic rays, is 20 to 99.9
% by weight, preferably 30 to 95% by weight. It also has a softening point between 45℃ and 80℃, and below the softening point,
It is preferable that the composition quickly changes into a fluid form and can be dispersed with water having a softening intention of 1- or water containing a surfactant.

``Softening point'' is the temperature at which the same width material rapidly changes to a liquid state (viscosity less than 6000 voids) by heating, and means that the temperature range from the start to the end of this phenomenon is within 5°C. (Softening point is JISK-62206) (Softening range 5℃
is the same as the melting point J l5K8220.6.4.2
) If the content of the components + Al in the present invention exceeds the - limit, the content of the other components will be too low and it will not be possible to obtain a sufficient amount of polymer through photopolymerization, resulting in the formation of the desired amount during hot water development. This is not preferred because it becomes difficult to obtain an image-forming body with high physical properties.

On the other hand, if the content of Y in component (8) is outside the limit, the photocrosslinking reaction will not take 1 minute, making it difficult to achieve the desired mechanical strength, elasticity, and hardness. So I don't like it.

Component (8) in the present invention includes any ethylenically unsaturated compound having properties as indicated by l- with a softening point between 45°C and 80°C. Examples of such compounds include ethylenically unsaturated group-containing paraffins and ethylenically unsaturated group-containing oligomers.

There are various methods for synthesizing paraffins containing ethylenically unsaturated groups. - Examples include the following methods.

Paraffins containing terminal hydroxyl groups (Polytail H, H
A Mitsubishi Kasei (manufactured by I'JJ) is terminally isocyanated with polyisocyanate, and then a hydroxyl group-containing (meth)acrylate is reacted to synthesize a terminally (meth)acrylated urethane prepolymer. Examples of the polyisocyanate include those containing two or more incyanate groups (for example, tolylene diisocyanate, methylene diphenyl diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, etc.). Contains hydroxyl group (meth)
Acrylates include hydroxyethyl (meth)
Examples include acrylate, hydroxypropyl (meth)acrylate, and the like. The following compounds can be converted into urethane acrylates by conventional methods.

Examples of the ethylenically unsaturated group-containing oligomer include low molecular weight polyester or polyether polyol urethane acrylate. Examples of such compounds include the Vlscoat series (manufactured by Osaka Organic Co., Ltd.).

Component 18) in the present invention is a polymer compound that can be mechanically mixed with component (8), and is used to adjust the elastic hardness of the composition after photoreaction and the softening point temperature during development processing. It's Uruchino. Preferably, a polymer compound having good compatibility with component (Δ) is used, such as not only hydrophobic low polarity elastomers such as ethylene propylene rubber and shrimp chlorohydrin rubber, but also crystalline polymer compounds, paraffins, hydrophilic polymer compounds, etc. However, any KX1 molecular compound that plays the role of component IBI can be used. In addition, the ingredients ([31 is photosensitive resin composition Imaichi%
It can be added in an amount of 5 to 80% by weight, preferably 9 to 69% by weight.

The component (C1) in the present invention, that is, the photopolymerization initiator capable of generating active species by actinic light, is capable of initiating photoradical polymerization. Useful photopolymerization initiators include adjacent polyketone compounds such as diacetyl, dibenzyl, etc., α- Carbonyl alcohols such as α-alkylbenzoin and others, and polynuclear quinones such as 1,4-naphthoquinone,
9.10-Anthraquinone, l-chloroanthraquinone and others, etc., are mentioned! 11 Used alone or in combination. The amount of photopolymerization initiator is 0 based on the total weight of the photosensitive resin composition.
．． It can be added in an amount of 0.01 to 10% by weight, preferably 0.1 to 5% by weight.

In the present invention, components + Al, II31 and (C)
In addition, a thermal polymerization inhibitor can be added. This is added to prevent only thermal polymerization in the rat without inhibiting the photocrosslinking reaction, and is preferably 0 to 5 Ir + - % relative to the photosensitive resin composition Kaneko A.
It can be added in the range of ~211i1%. Useful thermal polymerization inhibitors include, for example, hydroquinone, hydroquinone monomethyl ether catechol, and pt-butyl catechol.

The photosensitive resin composition comprising the components (Al, +[31 and (C), or thermal polymerization inhibitor 11-) in the present invention has a softening point of 45 due to the properties of the main component +Al.
~80°C, and has the property of being dispersed by softening intention 1-warm water or warm water containing a surfactant.

Note that since the component to be developed is solidified at room temperature, it is easy to separate it from the developer. Further, in a developer system containing a surfactant, the components to be developed are completely emulsified, so there is no problem in post-processing.

Surfactants are added to prevent the components to be developed from adhering to the image forming area or remaining in the area to be developed and damaging the remaining part of the plate. The surfactant is not limited to any surfactant such as anionic surfactant, surfactant surfactant, nonionic surfactant, etc., as long as it separates and emulsifies, and there are no limitations on the type of surfactant to be added.

Since the photosensitive resin composition of the present invention is in a solution state at high temperatures, it can be easily prepared by adding and mixing a photopolymerization initiator or a thermal polymerization inhibitor without a solvent and heat-pressing it onto a suitable substrate. I can do it.

The ultraviolet rays used for curing the photosensitive resin of the present invention range from 150 to 500. A wavelength of approximately 300 to 400 nm is particularly effective, and the light source to be used is preferably a low-pressure mercury lamp, a high-pressure mercury lamp, or a carbon arc lamp.

In the photosensitive resin composition of the present invention, a negative film having a transparent image is irradiated with ultraviolet rays using the above-mentioned light source, and the unexposed non-image areas are washed out with warm water or warm water containing a surfactant to form a relief image. You can get it.

The photosensitive resin composition obtained by the present invention has rubber elasticity, alcohol resistance, water resistance, ink transfer property, printing durability,
Due to its excellent properties, it is preferred as a plate material for flexographic printing. In addition to flexographic printing plates, the photosensitive resin composition of the present invention can also be used as an elastomer that can be cured by ultraviolet light, such as adhesives, films, photoresist materials,
It can be used not only for image forming materials such as paints but also for various sealing materials.

(Function) The feature of the present invention is that a compound that maintains the same width shape at room temperature due to crystallization or freezing breaks the crystalline state or frozen state when the temperature rises, and the viscosity decreases rapidly and becomes fluid. The point is that it has become possible to express image-forming ability through photopolymerization by controlling the substance with a compatible polymeric compound and imparting photosensitivity to the substance.

In addition, the main chain structure of component 18) itself is a hydrophobic structure, but sil', /! l! When exposed to water, it becomes fluid and disperses, and the exposed area becomes three-dimensional due to photoreaction, so the softening point becomes 1-1, and it becomes difficult to disperse in hot water, making it difficult to form an image.

The composition of the present invention consists of 1. l: Since the chain itself maintains a hydrophobic structure, there is no problem with water resistance caused by the hydrophilic compound contained, which was a problem in conventional water-developable photosensitive resin compositions, and it is also compatible with various polar solvents including alcohol. It also has solvent resistance against.

That is, unlike conventional water-developable photosensitive resin compositions in which development was carried out by swelling and dispersing hydrophilic components, the present invention fluidizes hydrophobic components, which do not conventionally swell in water, at high temperatures.
This is an unprecedented water-developable photosensitive resin composition that exhibits water-developability by being dispersed in warm water or hot water containing a surfactant.

(Example) Examples will be explained below. Note that the present invention is not limited to the following embodiments.

Production Example 1 253.7 g of Polytail HA 1 40.8 g of hexamethylene diisocyanate 1 2.9 g of di-n-butyltinsilaurylate were added and reacted for 4 hours at 80°C under N2, and then 27 g of hydroxyethyl acrylate 1 0.005 g of phenothiazine was added. Then, the reaction was further carried out at 80° C. for 4 hours to obtain a urethane acrylate prepolymer. The viscosity of the obtained urethane acrylate prepolymer is 35℃
It was more than to, ooo poise at 50°C, and 300 poise at 70°C.

Production Example 2 Polytail HA 141.8g, Inphorone diisocyanate 31. Ogs di-n-butyltin silaurylate 2
．． After reacting with N2 at 80° C. for 6 hours, 12.1 g of hydroxyethyl acrylate and 0.002 g of phenothiazine were added, and the reaction was further carried out at 80° C. for 8 hours to obtain a urethane acrylate prepolymer. The viscosity of the obtained urethane acrylate prepolymer was 5,000 poise at 35°C, 5,000 poise at -050°C, and 500 poise at 80°C.

Examples 1 to 12 27 g of urethane acrylate prepolymer obtained in Production Examples 1 and 2, 3 g of the polymer compound shown in Table 1 above
and 0.3 g of dibenzyl dimethyl ketal in Table 1 above.
After heating and combining each sample in a solvent 40 shown in Table 1, the solvent was removed and a plate having a thickness of 2 mm was formed by heating. A negative film is attached to this, and a medium pressure mercury lamp is applied at 120 mw/cra.
Exposure was performed for B minutes. This at 60℃, 0.92w/
When immersed for 2 minutes in surfactant-containing water containing w% of sodium linear alkylbenzene sulfonate and sodium alkyl ether sulfate and subjected to brush development, the unexposed areas were completely washed out and a relief pattern was obtained. I was able to do that. The physical properties of each are also listed in Table 1.

Example 13 Viscoat 812 2B, 3 g of 7g1Z pichlorohydrin rubber and 0.3 g of dibenzyl dimethyl ketal were heated and mixed in 40° of THF solvent, the solvent was removed, and the mixture was heated and molded into a plate with a thickness of 2 as. Example 1
When exposed and developed (at a temperature of 65° C.) using the same method as above, a relief pattern was obtained. The hardness of the photocured part was 52 in Shore A hardness, the repulsion rate was 37%, the water absorption rate was 0.77%, and the ethanol absorption rate was 6.87%.

Comparative Example 1 28.7 g of paraffin (melting point 62-65°C), 3 g of shrimp chlorohydrin rubber, 0.3 g of dibenzyl dimethyl ketal
After heating and mixing in 4011 tJ of THF solvent, the solvent was removed and the mixture was heated and molded into a plate having a thickness of 2 and 1. This was exposed and developed in the same manner as in Example 1, but no effective image remained.

Comparative Example 2 Urethane acrylate polymer 10 obtained in Production Example 1
．． Add 0.1 g of dibenzyl methyl ketal to 0 g,
After heating and mixing at 80° C., the mixture was heated and molded into a plate having a thickness of 2+1111 mm. When this was exposed and developed in the same manner as in Example 1, the unexposed areas could not be washed out within 1 minute. To obtain relief, a temperature of 1° above 65° C. was required. The hardness of the photocured product is 68 on Shore A hardness.
The water absorption rate was 0, 61%, and the ethanol absorption rate was 4.99%.

(Efficacy of the invention! J!) The composition of the present invention having the above-mentioned structure maintains the same width at room temperature, but becomes fluid due to a rapid decrease in viscosity at high temperatures, and also has developability in the hydrophobic component. Since it is given,
It is a photosensitive resin composition that can be developed in an aqueous system and has excellent water resistance and alcohol resistance.

Claims (1)

[Claims] (1) (A) an ethylenically unsaturated compound that can be polymerized by actinic rays; (B) a polymer compound that can be mechanically mixed with component (A); and (C) light that can generate active species by actinic rays. A photosensitive resin composition containing a polymerization initiator and having a softening point between 45 and 80°C.