JPH11249321A - Developing solution for flexographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate operational hygienic and environmental problems and to enable the formation of a relief patterns superior in dimensional stability and resolution and reproducibility by incorporating bromopropane as a main component or alcohols in addition to this bromopropane. SOLUTION: This developing solution for a flexographic printing plate contains bromopropane as a main component or alcohols in addition to this bromopropane. 1-bromopropane and 2-bromopropane can be used each alone or together with each other as the bromopropane. The developing solution containing the alcohols in addition to the bromopropane is suitable for practical uses. The alcohols to be used are not especially limited so long as they are mutually soluble to the bromopropanes but among them, isopropylalcohol, isobutyl-alcohol and benzylalcohol are suitable for attaining good developability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel developer for flexographic printing plates, and more particularly, it can form a relief excellent in dimensional stability, resolution and reproducibility, and has high safety and high work hygiene. And a developer used for making a flexographic printing plate, which is environmentally preferable.

[0002]

2. Description of the Related Art A flexographic printing plate is prepared by laminating a photosensitive resin composition containing a thermoplastic elastomer, a photopolymerizable unsaturated monomer and a photopolymerization initiator on a substrate, and forming a required pattern on the substrate. After irradiating with actinic light through a mask having
It is manufactured by dissolving or swelling a portion not irradiated with actinic rays with a developer. Conventionally, in the production of flexographic printing plates, chlorine-based organic solvents such as chloroform, trichloroethane, trichloroethylene, and tetrachloroethylene, and developers in which alcohols are mixed with these solvents have been frequently used.

[0003]

However, the developing solution comprising the above-mentioned chlorine-based organic solvent swells not only the unirradiated portion but also the exposed portion, so that the relief having excellent dimensional stability, resolution and reproducibility is obtained. In addition to being unable to obtain a pattern, it is highly toxic to the human body and poses a problem in terms of occupational hygiene.In recent years, it has been found that this contributes to the ozone layer destruction, and it has become impossible to say that it is a preferable developer in terms of environmental problems. I have. For these reasons, the emergence of a non-chlorine-based developer is desired, and a developer in which an aromatic hydrocarbon is mixed with a paraffin-based and a naphthenic-based hydrocarbon at a specific volume ratio (Japanese Patent Laid-Open No. 3-3 / 1990).
No. 22416) has been proposed. The developer is less problematic in terms of work hygiene and the environment than a conventional developer containing a chlorine-based organic solvent, but it is troublesome to handle because of its low flash point, and it has a bad smell, and also has a bad odor during development. The swelling of the image area was not sufficiently suppressed, and it was difficult to obtain a relief pattern with high reproducibility.

In view of this situation, the present inventors have conducted intensive studies, and as a result, a developing solution containing bromopropane as a main component or a developing solution containing an alcohol in addition to the bromopropane has been found to be useful for work hygiene purposes. The inventors have found that a relief pattern excellent in dimensional stability, resolution and reproducibility can be formed without causing environmental problems, and the present invention has been completed. That is,

An object of the present invention is to provide a developer for a flexographic printing plate which can form a relief pattern which is free from occupational hygiene and environmental problems and has excellent dimensional stability, resolution and reproducibility. I do.

[0006]

The present invention, which achieves the above object, relates to a developer for flexographic printing plates containing bromopropane as a main component or containing alcohols in addition to the bromopropane.

The developer for flexographic printing plates of the present invention contains bromopropane as a main component as described above. As the bromopropane, either 1-bromopropane or 2-bromopropane can be used alone or in combination. Further, in addition to the bromopropane, alcohols may be contained. Particularly, a developer containing alcohols is practical and suitable.

The alcohol is not particularly limited, but may be any alcohol having compatibility with bromopropane, and specifically, for example, methyl alcohol,
Ethyl alcohol, propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, amyl alcohol, isoamyl alcohol, secondary amyl alcohol, 3-pentanol, tertiary amyl alcohol, hexanol, 2-ethylhexanol, methyl amyl alcohol, 2 -Ethylbutanol, 2-heptanol, 3-heptanol, octanol, 2-octanol, 2-ethylhexanol, 3,5,5-trimethylhexanol, nonanol, decanol, undecanol, dodecanol, 2-phenylethanol, cyclohexanol, methylcyclo Hexanol, benzyl alcohol, glycidol, furfuryl alcohol,
Tetrahydrofurfuryl alcohol, diacetone alcohol, ethylene glycol, diethylene glycol, triethylene glycol or its monoalkyl ether,
3-methoxybutanol, 2-butoxyethanol, 3
Examples thereof include -methoxy-3-methylbutanol and 4- (4'-methoxybutoxy) butanol, and among them, isopropyl alcohol, isobutyl alcohol and benzyl alcohol are preferable because good developability can be achieved.

The compounding ratio of bromopropane in the developer for flexographic printing of the present invention is in the range of 50 to 100% by weight, preferably 60 to 80% by weight. The mixing ratio of the alcohol added to the developer is selected in the range of 0 to 50% by weight, preferably 20 to 40% by weight. If the blending ratio of bromopropane is outside the above range, dimensional stability and reproducibility deteriorate, which is not preferable. On the other hand, if the amount of the alcohol is more than 50% by weight, the swelling-inhibiting action becomes large, which undesirably increases the development processing time.

[0010] In addition to the above-mentioned components, the developing solution of the present invention may contain other organic solvents, surfactants and the like, if desired, as long as the object of the present invention is not impaired.

The developer for a flexographic printing plate of the present invention is a developer for a flexographic printing plate formed of a photosensitive resin composition containing a thermoplastic elastomer, a photopolymerizable unsaturated monomer and a photopolymerization initiator. As the thermoplastic elastomer, styrene-based, olefin-based, polyester-based, polyurethane-based, and 1,2-polybutadiene having the same rubber elasticity as vulcanized rubber at normal temperature and exhibiting thermoplasticity at high temperature are used. Resin, vinyl chloride resin, polyamide resin or the like is used. Particularly preferred thermoplastic elastomers include styrene-based thermoplastic elastomers, and specifically, styrene / butadiene / styrene block copolymers, styrene / isoprene / styrene block copolymers, and hydrogenated products thereof are most suitable. It is. 30 to 95% by weight of the thermoplastic elastomer in the photosensitive resin composition,
Preferably, it is blended at a ratio of 50 to 85% by weight. If the amount is less than 30% by weight, a composition excellent in rubber elasticity cannot be obtained, and if the amount exceeds 95% by weight, it becomes difficult to form a pattern having excellent reproducibility.

The photopolymerizable unsaturated monomer is not particularly limited as long as it is a compound having good compatibility with the above-mentioned thermoplastic elastomer, and specific examples thereof include acrylates, acrylamides, and the like. Methacrylic esters, methacrylamides, allyl compounds, vinyl ethers,
There are vinyl esters, styrenes, crotonic esters, and the like, which are selected from compounds having one addition-polymerizable unsaturated bond. The alcohols forming the ester include aliphatic or alicyclic diols having 2 to 10 carbon atoms, preferably 2 to 6 carbon atoms, for example, ethylene glycol,
Triethylene glycol, hexanediol, cyclohexanediol and the like are selected. The photopolymerizable unsaturated monomer may be used alone or in combination of two or more. The compounding amount thereof is 3 to 80 parts by weight, preferably 5 to 20 parts by weight, based on 100 parts by weight of the thermoplastic elastomer. It is selected in the range of parts by weight. If the content of the photopolymerizable unsaturated monomer is less than 3 parts by weight, a pattern with excellent reproducibility cannot be obtained, and if it exceeds 80 parts by weight, good rubber elasticity cannot be obtained.

Further, the photopolymerization initiator can be arbitrarily selected from known photopolymerization initiators commonly used for photosensitive resins. In particular, benzoin, benzophenone and anthraquino are preferred. These photopolymerization initiators may be used alone or in combination of two or more. The compounding amount of the photopolymerization initiator is selected in the range of 0.1 to 5 parts by weight, preferably 0.5 to 2 parts by weight, based on 100 parts by weight of the thermoplastic elastomer. If the amount is less than 0.1, practical sensitivity cannot be obtained, and if it exceeds 5 parts by weight, a good pattern cannot be obtained.

The photosensitive resin composition may further contain a dye, a pigment, a polymerization inhibitor, an antioxidant, an anti-photodegradation agent and the like, if necessary, to improve the performance.
Further, in order to improve the wear resistance, a resin compatible with the thermoplastic elastomer, for example, a polyamide resin, an epoxy resin, a polyurethane resin or the like can be mixed.

The flexographic printing plate using the above photosensitive resin composition can be prepared according to a known method, for example, a thermoplastic elastomer, a photopolymerizable unsaturated monomer, a photopolymerization initiator, and various additives used as desired. Is dissolved in an organic solvent, and formed into a film or plate as it is, and then the solvent is removed or mixed with a roll mixer.
It is manufactured by forming into a film or plate shape by hot pressing and pressing it to a polyester plate, steel plate, aluminum plate or the like. Further, a water-soluble or alcohol-soluble resin (hereinafter referred to as "adhesion") comprising a cellulose derivative, polyamide or polyimide is provided on the surface of the photosensitive resin layer in order to prevent desensitization and adhesion due to oxygen in the atmosphere. (Referred to as a prevention resin) in a thickness of 1 to 10 μm to form a coating film.

The flexographic printing plate is selectively irradiated with an actinic ray through a mask, and then the unexposed portion is washed out with a developing solution to produce a flexographic printing relief plate having rubber elasticity. The washing is usually performed by brushing or spraying with a spray.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described, but the present invention is not limited thereto.

[0018]

Example 1 To 200 parts by weight of methyl ethyl ketone, TRKX65S (manufactured by Shell Chemical Company, weight average molecular weight: 130,000, styrene unit content: 28% by weight) was used as a thermoplastic elastomer composed of styrene / butadiene / styrene block copolymer.
0 parts by weight, liquid polybutadiene NISSO-PB
B-1000 (manufactured by Nippon Soda Co., Ltd., weight average molecular weight 105
0,1,2-vinyl 85% by weight or more) 60 parts by weight, trimethylolpropane triacrylate 6 parts by weight, benzyldimethylketal 2 parts by weight, and 2,6-di-tert
-Butyl-p-cresol 0.012 parts by weight was added and dissolved in the flask while stirring under reflux for about 2 hours.
A photosensitive resin composition was obtained. This is provided with an adhesive layer 100
After coating on a μm polyester film (PET film) so that the film thickness after drying becomes 2.74 mm,
It dried at 60 degreeC for 12 hours, and formed the photosensitive resin layer.

On the other hand, methanol 1 was placed on a PET film having a thickness of 100 μm so that the film thickness after drying was 5 μm.
A composition consisting of 00 g and 5 g of Macromelt 6900 (manufactured by Henkel, alcohol-soluble polyamide) was applied and dried at 60 ° C. for 2 minutes. Next, this polyamide film was laminated after applying an adhesive to the surface of the photosensitive resin layer.

Next, after irradiating the entire surface with actinic rays for 2 minutes from the support side with a chemical lamp FL-40BL (manufactured by Toshiba Corporation), the PET film on the polyamide coating side was peeled off, and the photosensitive resin layer was coated with 0.1 μm. A negative film capable of reproducing an independent fine line of 1 mm width was adhered under reduced pressure, and activated light was selectively irradiated with the chemical lamp for 15 minutes.

The obtained flexographic photosensitive printing plate is subjected to a developing treatment at 25 ° C. for 2 minutes by a brush type developing machine using a developing solution comprising a mixed solution of 60% by weight of 1-bromopropane and 40% by weight of isopropyl alcohol, The unirradiated portion of the photosensitive resin layer was dissolved and removed, and dried at 50 ° C. for 30 minutes.
Next, the entire surface was irradiated with the chemical lamp for another 15 minutes to produce a flexographic printing plate.

On the flexographic printing plate, a relief pattern faithful to the image of the negative film and having high dimensional stability and reproducibility is formed, and a fine 0.1 mm independent line is well maintained. It was a relief pattern with excellent properties. Furthermore, as a result of measuring the independent line width of 0.1 mm, the independent line width was 0.098 mm. Table 1 shows the results.

Example 2 A polyamide film was laminated on the photosensitive resin film obtained in Example 1 via an adhesive in the same manner as in Example 1, and selectively irradiated with active light for 15 minutes.

Then, 1-bromopropane 80% by weight,
As a developer consisting of a mixed solution of 20% by weight of isopropyl alcohol, a developing treatment was carried out by a brush developing machine in the same manner as in Example 1, and the unirradiated portion of the photosensitive resin layer was dissolved and removed, followed by drying at 50 ° C. for 30 minutes. Then, the entire surface was irradiated with a chemical lamp for 15 minutes to obtain a flexographic printing plate.

The obtained flexographic printing plate has a relief pattern which is faithful to the image of the negative film, has high dimensional stability and high reproducibility, and has a fine 0.1 mm independent fine line. It was an excellent relief pattern. Furthermore, as a result of measuring the independent line width of 0.1 mm,
The independent line width was 0.098 mm. Table 1 shows the above results.
Shown in

Example 3 A 100 μm polyester film (PRT film) provided with an adhesive layer using the photosensitive resin composition obtained in Example 1
It was applied on the top so that the film thickness after drying was 2.74 mm, and then dried at 60 ° C. for 12 hours to form a photosensitive resin layer.

Next, a negative film capable of reproducing an independent fine line having a width of 0.1 mm was brought into close contact with a roller on the photosensitive resin layer, and activated light was selectively irradiated for 15 minutes in the same manner as in Example 1.

Next, using a developing solution composed of 1-bromopropane, a developing treatment is performed at 25 ° C. for 1 minute and 10 seconds by a brush type developing machine to dissolve and remove unirradiated portions of the photosensitive resin layer. After drying at 50 ° C. for 30 minutes, the entire surface was irradiated with a chemical lamp for 15 minutes to obtain a flexographic printing plate.

The obtained flexographic printing plate has a relief pattern which is faithful to the image of the negative film, has high dimensional stability and high reproducibility, and has a fine 0.1 mm independent fine line. It was an excellent relief pattern. Furthermore, as a result of measuring the independent line width of 0.1 mm,
The independent line width was 0.093 mm. Table 1 shows the above results.
Shown in

Comparative Example 1 A polyamide film was laminated on the photosensitive resin film obtained in Example 1 via an adhesive in the same manner as in Example 1, and then selectively irradiated with actinic rays for 15 minutes.

Then, 1-bromopropane 45% by weight,
Using a developer consisting of a mixed solution of 55% by weight of isopropyl alcohol, the same developing treatment as in Example 1 was performed by a brush developing machine to dissolve and remove the unirradiated portion of the photosensitive resin layer. After drying for 15 minutes, the entire surface was irradiated with a chemical lamp for 15 minutes to obtain a flexographic printing plate.

Since the obtained flexographic printing plate takes a long time for development processing, a relief pattern excellent in dimensional stability and reproducibility cannot be obtained with respect to an image of a negative film. The width was 0.2 mm.
Table 1 shows the results.

Comparative Example 2 A polyamide film was laminated on the photosensitive resin film obtained in Example 1 through an adhesive in the same manner as in Example 1, and the active light was selectively irradiated for 15 minutes.

Next, 40% by weight of Swazol 1800 (manufactured by Maruzen Petrochemical Co., Ltd .: aromatic hydrocarbon), Isopar H
Using a mixed solution of 30% by weight (manufactured by Esso: aliphatic hydrocarbon) and Solfit (manufactured by Kuraray: 3-methoxy-dimethylbutanol) as a developing solution, the same development as in Example 1 was performed by a brush-type developing machine. After the treatment, the unirradiated portion of the photosensitive resin layer was dissolved and removed, followed by drying at 50 ° C. for 50 minutes, and then irradiating the entire surface with a chemical lamp for 15 minutes to obtain a flexographic printing plate.

In the obtained flexographic printing plate, a relief pattern having high reproducibility cannot be obtained because the expansion of the image area in the developing process is insufficiently suppressed, and the minimum independent line reproduction width is 0.2 mm. Met. Table 1 shows the results.

[0036]

[Table 1]

[0037]

The developer for a flexographic printing plate of the present invention can wash out a relief pattern excellent in resolution, dimensional stability and reproducibility, and can easily produce a highly accurate flexographic printing plate. Further, since the flexographic printing plate developer is non-chlorine-based, it is practical without problems in terms of work hygiene and environment.

Claims (2)

[Claims] 1. A flexographic printing plate developer comprising bromopropane as a main component. 2. The developing solution for a flexographic printing plate according to claim 1, further comprising an alcohol.