JPH0239784B2 - KANKOSEIJUSHISOSEIBUTSU - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a photosensitive resin composition. Conventional technology Conventionally, synthetic resins have been used as vehicles and adhesives for paints and inks, but when the painted or adhesive surface is flexible, general synthetic resins are not suitable, and rubber elasticity It is necessary to use a resin having a so-called rubber. However, ordinary acrylic rubber and diene rubber are originally insoluble in water, and are similarly insoluble in alkaline and acidic aqueous solutions, so they cannot be used by dissolving them in organic solvents. There is. However, most organic solvents are harmful to the human body and flammable, so if an aqueous solvent can be used as the solvent, it is extremely useful from a safety standpoint. Carboxyl group-containing polymers are known as resins soluble in aqueous solvents, but conventional polymers have poor rubber elasticity and poor transparency required for paint ink vehicles and adhesives. Furthermore, a conjugated diene copolymer soluble in an alkaline aqueous solution has been proposed as a component of a photosensitive composition for photoresist (Japanese Patent Publication No. 1140/1983).
The transparency was insufficient, and there was room for improvement in rubber elasticity. Further, the photocurability of the copolymer itself was insufficient. Furthermore, recently, a conjugated diolefin (diene) hydrocarbon (A) and an α,β-ethylenically unsaturated carboxylic acid (B) are essential components, and a monoolefin-based unsaturated compound (C) is added to the essential components. A copolymer containing
A photosensitive resin composition containing () a photopolymerizable unsaturated monomer and () a photosensitizer has been proposed (Japanese Patent Publication No. 59-29849). Problems to be Solved by the Invention However, although the photosensitive resin composition described in Japanese Patent Publication No. 59-29849 has many advantages, there are some problems in the transparency and processability of the final composition. It has been found. The present invention has been made in view of the above, and is soluble in alkaline aqueous solution, has excellent processability and photocurability, and has excellent rubber elasticity and transparency even after curing.
It is an object of the present invention to provide a photosensitive resin composition that also has excellent water resistance. Means for solving the problems, that is, the present invention provides () a conjugated diene compound (A)
A: A:
10-80 mol%, B: 5-60 mol%, C: 0.1-
20 mol%, D: 0 to 80 mol% of a copolymer, () a photopolymerizable unsaturated monomer, and () a photosensitizer. It provides: Examples of the conjugated diene compound as the monomer (A) component constituting the copolymer () of the present invention include 1,3-butadiene, isoprene, chloroprene, and 1,3-pentadiene. If the content of component (A) is less than 10 mol%, the rubber elasticity will be poor, and if it exceeds 80 mol%, the solid retention properties and processability of the composition will be poor. The preferred range is 20-40 mol%. Examples of the α,β-ethylenically unsaturated carboxylic acid of the monomer (B) component constituting the copolymer () of the present invention include acrylic acid, methacrylic acid, maleic acid,
Examples include fumaric acid, monoethyl maleate, and itaconic acid. If the content of component (B) is less than 5 mol%, the alkali water solubility will be poor, and if it exceeds 60 mol%, the rubber elasticity will be poor. The preferred range is 10~
It is 30 mol%. The polyfunctional vinyl compound of the monomer (C) component constituting the copolymer () of the present invention is a compound containing two or more vinyl bonds in one molecule and having equivalent reactivity. Examples include polyvalent acrylate compounds such as ethylene glycol dimethacrylate, ethylene glycol diacrylate, trimethylolpropane trimethacrylate, propylene glycol dimethacrylate, and propylene glycol diacrylate, and divinylbenzene and trivinylbenzene. If the content is less than 0.1 mol%, transparency and processability will be poor.
If it exceeds 20 mol%, the alkali water solubility will be poor. The preferred range is 0.5 to 5 mol%. The monoolefinic unsaturated compounds of the monomer (D) component constituting the copolymer () of the present invention include ethyl acrylate, n-butyl acrylate, α
-ethylhexyl acrylate, n-octyl acrylate, dodecyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, butoxyethyl acrylate, cyanoethyl acrylate, hydroxyethyl acrylate,
Acrylic acid ester compounds represented by hydroxypropyl acrylate or their methacrylates, styrene, acrylonitrile, vinyl chloride, ethylidenenorbornene, propenylnorbornene, dicyclopentadiene, cyclopentadiene, etc. are used alone or in combination depending on the purpose. The content of component (D) is at most 80 mol%, preferably 20 to 60 mol%, in order to maintain the present invention based on the contents of other components. If it is less than 20 mol%, the components (A) and (B) will be relatively large; if the components (A) and (B) are too large, solid retention will be poor, and if the component (B) is too large, the rubber elasticity will be poor. become inferior.
More preferably, it is 30 to 40 mol%. In addition, the intrinsic viscosity [η] (30°C, in dimethylformamide) of the copolymer ( ) of the present invention is 0.01
-3.0 dl/g, preferably 0.1-2.0 dl/g.
If it is less than 0.01 dl/g, solid retention will be difficult and it will be difficult to handle, and if it exceeds 3.0 dl/g, processability will be poor. Such a copolymer () is a conjugated diene compound
(A) 5-50% by weight, α,β-ethylenically unsaturated carboxylic acid (B) 5-30% by weight, polyfunctional vinyl compound (C)
This is carried out by radical polymerizing a mixture of 0.5 to 20% by weight and 0 to 60% by weight of the monoolefinic unsaturated compound (D). A molecular weight regulator is used to adjust the molecular weight. The amount used is preferably 0.1 to 5 g per 100 g of monomer. Each monomer and a polymerization agent such as a radical initiator may be added in their entirety to the reaction initiator, or may be added in arbitrary portions after the start of the reaction. Polymerization is carried out at 0 to 50°C in a reactor from which oxygen has been removed, but operating conditions such as temperature and stirring can be arbitrarily changed during the reaction. The polymerization method can be either continuous or batchwise. Examples of radical initiators include organic peroxides such as benzoyl peroxide, cumene hydroperoxide, paramethane hydroperoxide, and lauroyl peroxide, diazo compounds represented by azobisisobutyl dinitrile, inorganic compounds represented by potassium persulfate, and organic A redox catalyst, typified by a compound-iron sulfate combination, is used. As the molecular weight modifier, tert-dodecyl mercaptan, dialkylxanthogen disulfide, etc. are used. The copolymer () of the present invention is one in which the remaining double bonds derived from the conjugated diene compound are three-dimensionally crosslinked by the action of actinic rays such as ultraviolet rays and become insolubilized in a solvent, and the copolymer (2012) also has at least one in the molecule. It has been found that the addition of a photopolymerizable unsaturated monomer containing an ethylenically unsaturated group promotes the crosslinking reaction and significantly improves the mechanical strength of the printing plate etc. obtained after the crosslinking reaction. The photopolymerizable unsaturated monomer () used in the present invention includes styrene, α-methylstyrene, m-methylstyrene, p-methylstyrene,
Unsaturated aromatic compounds such as p-methoxystyrene, diisopropenylbenzene and divinylbenzene, unsaturated nitrile compounds such as acrylonitrile and methacrylonitrile, methyl acrylate,
Ethyl acrylate, propyl acrylate, n
- Acrylates or methacrylates of alkyl alcohols such as butyl acrylate, isobutyl acrylate, tert-butyl acrylate, n-pentyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-decyl acrylate, lauryl acrylate, etc., 2 - Acrylates or methacrylates of hydroxyalkyl alcohols such as hydroxyethyl acrylate, 2-hydroxypropyl acrylate or methacrylate, acrylates or methacrylates of alkoxyalkylene glycols such as methoxyethylene glycol, methoxypropylene glycol, maleic acid, fumaric acid, maleic anhydride , α,β-ethylenically unsaturated carboxylic acids such as crotonic acid, itaconic acid, itaconic anhydride, citraconic acid, and mesaconic acid; unsaturated polycarboxylic acids such as monoethyl maleate, monoethyl fumarate, and monoethyl itaconate; Monoesters, dimethyl maleate, diethyl maleate,
Diesters such as dibutyl maleate, dioctyl maleate, diethyl fumarate, dibutyl fumarate, dioctyl fumarate, dimethyl itaconate, diethyl itaconate, dibutyl itaconate, dioctyl itaconate, acrylamide, methacrylamide, N,N'- Acrylamides or methacrylamides such as methylene bisacrylamide and N,N'-hexamethylene bisacrylamide, ethylene glycol diacrylate or dimethacrylate, diacrylate or dimethacrylate of polyalkylene glycol (2 to 23 single alkylene glycols), glycerin , diacrylates and triacrylates of polyhydric alcohols such as pentaerythritol, trimethylolalkanes, and tetramethylolalkanes (alkanes include methane, ethane, and propane);
tetraacrylate or dimethacrylate, trimethacrylate or tetramethacrylate,
Examples include oligoacrylates. The photopolymerizable monomer () is a copolymer ()
It is used in an amount of 5 to 200 parts by weight, preferably 10 to 100 parts by weight, per 100 parts by weight. Within this range, two or more types can be used in combination. If the amount is less than 5 parts by weight, sufficient curing of the photosensitive resin layer and improvement in the mechanical strength of the printing plate etc. cannot be expected, and if it exceeds 200 parts by weight, the rubber elasticity of the copolymer () will be significantly impaired. It has drawbacks such as decreased solvent resistance. The () photosensitizer used in the present invention includes:
Usually used as a photoreaction initiator, for example, α-diketone compounds such as diacetyl and benzyl,
Examples include airoins such as benzoyl and pivaloin, acyloin ethers such as benzoin methyl ether, benzoin ethyl ether, and benzoin propyl ether, and polynuclear quinones such as anthraquinone and 1,4-naphthoquinone. The amount of the photosensitizer () added is 0.1 to 10 parts by weight, preferably 1 to 10 parts by weight, per 100 parts by weight of the copolymer ().
It is 5 parts by weight. If it is less than 0.1 parts by weight, sufficient curing cannot be given to the photosensitive resin layer, and if it exceeds 10 parts by weight, not only is it uneconomical because all of the added photosensitizer does not participate in the reaction, but also Sometimes, the compatibility with the copolymer (2) or the photopolymerizable monomer (2) is poor, resulting in non-uniform dispersion. Commercially available products of the photopolymerizable unsaturated monomers () mentioned above usually contain a small amount of a thermal polymerization inhibitor such as p-methoxyphenol, but this is necessary when exposing the photosensitive resin. It has no effect at all, but rather acts as a storage stabilizer for the photosensitive resin composition, so when creating the composition, the thermal polymerization inhibitor is added as is without being removed from the photopolymerizable unsaturated monomer. can do. Furthermore, storage stabilizers such as hydroquinone, p-methoxyphenol, p-tert-butylcatechol, 2,6-di-tert-butyl-p-
Hydroxy aromatic compounds such as cresol and pyrogallol, benzoquinone, p-torquinone, p-
Quinones such as xyquinone, phenol-α-
An amine such as naphthylamine can be added in an amount of 0.01 to 2 parts by weight per 100 parts by weight of the copolymer. A method for producing a photosensitive resin composition containing the () copolymer, () photopolymerizable unsaturated monomer, and () photosensitizer of the present invention includes adding a solution to the copolymer after polymerization. Add an appropriate amount of the photopolymerizable unsaturated monomer and photosensitizer, stir thoroughly to make a homogeneous solution, and then remove the solvent under reduced pressure while heating, or remove the solvent under reduced pressure in advance to increase the copolymer. A method may be used in which a photopolymerizable unsaturated monomer and a photosensitizer are added and mixed while heating the mixture as a viscous or solid material. The photosensitive resin composition obtained in this way is either a liquid photosensitive resin composition or a rubber-like solid photosensitive resin composition, so it is necessary to sandwich a spacer with an appropriate thickness to maintain a constant film thickness. A photosensitive resin letterpress printing plate can be obtained by applying a negative film as a photosensitive resin layer of a constant thickness by coating it on a support using a roll coater or by compression molding, extrusion molding, etc., exposing it to light, and developing it. The photosensitive resin composition has high rubber elasticity and is therefore ideal for flexographic printing plates.
As a support for supporting the resin layer, a support having rubber elasticity comparable to that of the photosensitive resin composition can be used. Examples include natural rubber, styrene-butadiene rubber, butadiene rubber, acrylonitrile-butadiene rubber, isoprene rubber, ethylene-propylene rubber, crystalline 1,2-butadiene resin, and soft vinyl chloride resin. Films such as polyester, polypropylene, polystyrene, nylon, vinylidene chloride, polyethylene, etc. can also be used in areas where supports with small amounts of support can be used. Supports for using the photosensitive resin of the present invention in fields such as newspaper printing and general commercial printing include grained aluminum plates, iron plates,
You can also use magnesium plates. One of the features of the present invention is the ability to develop with a dilute aqueous alkali solution, but the alkali used may be any ordinary alkali, such as sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonia, lithium carbonate. A low concentration aqueous solution of about 0.1 to 1.0% by weight is used as a developer. Furthermore, the photosensitive resin composition of the present invention can of course be developed not only with an alkaline aqueous solution but also with an organic solvent such as alcohol, ketone, or aromatic hydrocarbon. Since the photosensitive resin composition of the present invention has high photosensitivity, exposure time can be shortened, and its solubility in a dilute alkali aqueous solution is extremely good and it can be developed in 1 to 2 minutes. Since printing can be performed immediately after drying, the complicated production process and production time of conventional rubber letterpress plates for flexographic printing can be significantly improved. In addition, it is of course possible to print with solvent-based flexo ink, but since it has good water resistance despite being soluble in alkali, it is also possible to print with water-based flexo ink, which is increasingly replacing solvent-based flexo ink due to air pollution concerns. be. The photosensitive resin composition of the present invention not only provides a resin plate for flexographic printing, but also a photosensitive material for newspapers, resin letterpress plates for general commercial printing, name plates, printed wiring, displays, and optical adhesives. It can be widely used as a vehicle for photocurable water-based and oil-based paints, ink, and adhesives that can be applied to flexible painted and adhesive surfaces. Effect When the conjugated diene compound (A) in the copolymer () constituting the photosensitive resin composition of the present invention is polymerized and incorporated into the copolymer, the main chain or side chain of the copolymer Since a double bond remains in the photoreaction, the radical of the photopolymerizable unsaturated monomer () is added to the double bond, and the composition after the photoreaction forms a strong three-dimensional network structure. In addition, water resistance and solvent resistance are enhanced, and the conjugated diene compound contained in the copolymer provides flexibility, that is, rubber elasticity, which is necessary for a flexographic printing plate.
α,β-ethylenically unsaturated carboxylic acid (B) increases the affinity of the photosensitive resin composition for a dilute alkali aqueous solution, that is, satisfies alkaline developability,
The polyfunctional vinyl compound (C) improves the transparency and processability of the photosensitive resin composition obtained, and the monoolefinic unsaturated compound (D) improves the transparency and processability of the photosensitive resin composition of the present invention. They each function to improve the mechanical properties of the printing plate, such as rubber elasticity, strength, and elongation, and to improve the printing surface of the printing plate, such as ink receptivity and ink transferability. In addition, the photopolymerizable unsaturated monomer () constituting the photosensitive resin composition of the present invention acts on the remaining double bonds derived from the conjugated diene compound to promote the crosslinking reaction, so that the The mechanical strength of the printing plate is greatly improved, and the photosensitizer (2) also functions to provide sufficient curing to the photosensitive resin layer. EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples as long as the gist thereof is not exceeded. Examples 1-6, Comparative Examples 1-2 Butadiene/ethyl acrylate/methacrylic acid/ethylene glycol dimethacrylate=
38/49.2/12/0.8 (mol%) copolymer 62.8% by weight, methanol solution 159.2g, nonaethylene glycol dimethacrylate 40.0g as a photopolymerizable unsaturated monomer, benzoyl isopropyl ether 2.0 as a photosensitizer. g and 0.1 g of hydroquinone as a storage stabilizer were placed in a 500 ml three-necked separable flask and stirred thoroughly until a solution was obtained. Next, the separable flask containing the contents was immersed in a water bath controlled at about 40°C, and the solvent methanol was removed under reduced pressure while stirring to obtain a viscous photosensitive resin composition (sample a). was created. 5.0g of the obtained photosensitive resin composition was mixed with styrene.
Placed on a butadiene rubber sheet (64 cm ² , 1.0 mm thick) and applied via an applicator with a spacing of 1.0 mm.
A 1.0 mm photosensitive resin layer was prepared. The photosensitive resin layer maintained solidity and had no problems in handling. Next, apply a negative film with an optical density of 3.5 while maintaining a distance of 0.3 mm from the resin layer.
The resin layer was exposed to ultraviolet light for 60 seconds using a 250 W ultra-high pressure mercury lamp from 60 cm above the surface. 0.5% by weight in the resin layer after exposure
When developed by spraying an aqueous sodium hydroxide solution for 2 minutes, the unexposed areas were completely dissolved and removed, making it possible to produce a resin letterpress faithful to the original image. The resin plate has rubber elasticity, and the rubber hardness (Shore A hardness, 20℃
measurement) was 60. Also, without using negative film
After front exposure for 60 seconds, the resin layer was punched out into a disc shape with a diameter of 3.5 cm, and the temperature was controlled at 40°C.
The degree of swelling was measured 24 hours after immersion in a wt% aqueous sodium carbonate solution and found to be 1.5%. When the resin letterpress plate was printed with black letterpress ink, printed matter with good ink transfer properties was obtained. Similarly, Table 1
Samples b to h shown in were also evaluated. The physical properties of the resulting photosensitive resin composition, such as alkali water solubility, transparency, and processability, were tested and evaluated by the following methods. (i) Alkaline water solubility Approximately 1 g of the resin composition is accurately weighed, 100 ml of a 1% by weight aqueous potassium hydroxide solution is added thereto, and the mixture is stirred at room temperature for 24 hours. Next, the entire amount is filtered through a 200-mesh wire mesh, and the residue remaining on the wire mesh is vacuum-dried at 80° C. for 20 hours. Insoluble content (%) is the amount of the original resin composition.
mg, weight of residue after filtration-drying in ng
It was expressed as 100n/m (%) and used as an index for the dissolution test. (ii) Transparency A sheet with a thickness of 0.5 mm was prepared and evaluated by the transmittance (%) of ultraviolet light at 370 mμ using an ultraviolet spectrophotometer. (iii) Processability When rolled on a hot roll (80 to 120°C), those with poor wrapping properties or those with severe stickiness that were difficult to process were marked as ×, and those with no problems with roll wrapping or shrinkage were marked as ○. In addition, polymers with low molecular weights and unable to maintain solidity were also judged to have poor processability from the viewpoint of handling.

[Table] As is clear from Table 1, when the copolymers () of the present invention of Examples 1 to 6 (samples a to f) are used, photosensitive resin compositions with excellent transparency and processability can be obtained. I know that it will happen. On the other hand, Comparative Example 1 (Sample g) using a copolymer containing no polyfunctional vinyl compound had poor processability, and Comparative Example 2 (Sample h) containing too much polyfunctional vinyl compound had poor alkali water solubility. is inferior,
It can be seen that there is a problem with alkali developability. Effects of the Invention The photosensitive resin composition of the present invention has various properties such as water resistance, solvent resistance, rubber elasticity, alkali developability, transparency, processability, and mechanical properties, and is suitable for flexographic printing as described above. In addition to providing a resin plate, it can also be widely used as a photosensitive material.

Claims (1)

[Scope of Claims] 1 () A conjugated diene compound (A), an α,β-ethylenically unsaturated carboxylic acid (B), and a polyfunctional vinyl compound (C) are essential components, and a monoolefin compound (C) is included as essential components. and the unsaturated compound (D), A: 10 to 80 mol%, B: 5 to 60 mol%, C: 0.1 to 20 mol%,
D: A photosensitive resin composition comprising a copolymer in a proportion of 0 to 80 mol%, () a photopolymerizable unsaturated monomer, and () a photosensitizer.