JPH0931337A - Production of photosensitive resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production process whereby a photosensitive resin compsn. developable with an aq. medium and contg. fine resin particles (a disperse phase) can be produced at a high productivity and to obtain a photosensitive resin compsn. which can be used for a form plate for printing capable of reproducing fine images with a high fidelity. SOLUTION: In producing a photosensitive resin compsn. which has a disperse phase mainly comprising a hydrophobic polymer and a hydrophilic polymer and having an average particle size lower than 10μm and a continuous phase mainly comprising a cross-linker and another hydrophobic polymer, a hydrophilic polymer, at least two hyrophobic polymers having mutually different affinities for the hydrophilic polymer, a cross-linker, a photopolymn. initiator, and a solvent compatible with the hydrophilic polymer are compounded, continuously melt mixed, and allowed to cause phase separation during being transferred.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a photosensitive resin composition used in a water-developable printing plate material, and particularly to a photosensitive resin composition useful as an aqueous developable flexographic printing plate. The present invention relates to a manufacturing method of.

[0002]

2. Description of the Related Art Usually, a flexographic printing plate material is used for printing on a flexible and easily deformable packaging material such as a cardboard or a film. Therefore, the plate material may have an appropriate elastic surface. It is necessary and a uniform sheet of a photosensitive resin composition containing a water-developable rubber component is used as a flexographic printing plate material. A photosensitive resin composition containing a rubber component is disclosed, for example, in JP-A-52-134655,
JP-A-53-10648, JP-A-61-22339
JP-A-60-173055, and regarding a photosensitive resin composition containing a rubber component capable of water development, JP-A-1-219735, JP-A-2-305805, and JP-A-2-305805,
As described in JP-A-3-72357, etc., based on a hydrophobic polymer having a glass transition temperature Tg of 5 ° C. or less and a hydrophilic polymer containing chlorine, a crosslinking agent, a photopolymerization initiator or a heat stabilizer is used. It can also be obtained from a composition containing

Further, in addition to the above, as a photosensitive resin composition containing resin fine particles which can be developed with water and have resistance to water-based ink, JP-A-2-175702 and JP-A-3-228060.
JP-A-5-150451, JP-A-4-29390
7, JP-A-4-29309, and JP-A-4-2943.
53, JP-A-4-340968, and JP-A-5-327.
No. 43, Japanese Patent Application Laid-Open No. 5-204139, and other photosensitive resin compositions.

In order to prepare a printing plate material using the above composition, the composition is adjusted with a solvent, the solvent is evaporated, and the remaining solvent is concentrated to a specific amount or less and discharged. Then, a printing plate material can be obtained by laminating it on a support to form a sheet having a uniform thickness.

Regarding the method for producing these photosensitive printing plate materials, not only the batch-type production method using a general kneading tank but also EP-A-03.
There are known manufacturing methods such as 62641 and DE-A-2942183 that enable continuous production.

According to the conventional batch-type or continuous-type production method using the above composition, the photosensitive resin composition produced is composed of particles having a particle size of 10 to several tens of μm, such as corrugated board and film. It has been considered relatively difficult to delicately print on flexible and easily deformable objects. Further, as a method for producing a printing plate material having a fine particle structure for performing delicate printing, a batch-type production method is mainly used, and a method with poor production efficiency has been performed.

[0007]

SUMMARY OF THE INVENTION The present invention solves various problems that cannot be solved by the above-mentioned prior arts, and therefore, it is possible to continuously produce a photosensitive resin composition using resin fine particles capable of being developed with water, which has high productivity. An object of the present invention is to provide a method for obtaining a photosensitive resin composition used for a printing plate material that can faithfully restore a delicate image while obtaining a manufacturing method.

[0008]

[Means for Solving the Problems] In order to solve the above problems, the inventors of the present invention have made various efforts as a result of various researches, and finally completed the present invention. That is, the present invention is a method for obtaining a photosensitive resin composition having a dispersed phase mainly composed of a hydrophobic polymer and a hydrophilic polymer, and a continuous phase mainly composed of a cross-linking agent and a hydrophobic polymer different from the hydrophobic polymer, Polymers, two or more kinds of hydrophobic polymers having different affinities with the hydrophilic polymer, a cross-linking agent,
A method for producing a photosensitive resin composition, characterized in that a solvent compatible with the photopolymerization initiator and the hydrophilic polymer is blended, and phase-separated during continuous melt mixing and transfer.

The hydrophilic polymer used in the present invention is water or an alkaline aqueous solution containing water as a main component,
Means a polymer that is soluble or swells (disperses) in a developer containing an acidic aqueous solution, an organic solvent, or a surfactant.
O ₂ M group, —SO ₃ M group, (M represents a hydrogen atom, periodic table group I, II, III elements, amine, ammonium)-
It is a linear, non-crosslinked polymer having hydrophilic groups such as NH ₂ and —OH. Examples of such hydrophilic polymers include general-purpose resins such as polyvinyl alcohol (PVA) and carboxymethyl cellulose, diene rubber obtained by copolymerizing (meth) acrylic acid and a diene compound, and liquid polybutadiene modified with maleic anhydride. A particularly effective skeleton is a polymer having -COOM (M is a hydrogen atom, I, II, III group element of the periodic table, amine, ammonium) in an amount of 50 to 50,000 equivalent / 10 ⁶ g, The group I and II elements of the periodic table are sodium,
Alkali metals such as potassium and lithium, calcium,
Examples thereof include alkaline earth metals such as magnesium, boron, aluminum and the like. In the present invention, -COO
When the M group is less than 50 equivalent / 10 ⁶ g, the affinity for water is poor and it is difficult to develop with neutral water.
When it exceeds the equivalent / 10 ⁶ g, the water-based ink resistance deteriorates, which is not preferable.

The hydrophilic polymer is specifically --COO.
M group-containing polyurethane, -COOM group-containing polyurethane, -COOM group-containing polyester, -COOM group-containing epoxy compound, -COOM group-containing polyamic acid, -C
OOM group-containing acrylonitrile-butadiene copolymer, -COOM group-containing styrene-butadiene copolymer, -COOM group-containing polybutadiene, polyacrylamide, sodium polyacrylate, polyvinyl alcohol (PVA), carboxymethyl cellulose (CM
C), hydroxyethyl cellulose (MRC), methyl cellulose (MC), polyethylene oxide, polyethylene imine, and derivatives thereof can be used,
It is not limited to these.

The compounds used to neutralize at least a part of the carboxyl groups contained in the hydrophilic polymer include hydroxides of alkali metals such as sodium hydroxide, lithium carbonate, potassium carbonate, carbonic acid. Including alkali metal carbonates such as sodium, potassium t-butoxide, alkoxides of alkali metals such as sodium methoxide, hydroxides of polyvalent metals such as calcium hydroxide, magnesium hydroxide and aluminum hydroxide, and aluminum isopropoxide. Polyvalent metal alkoxides, tertiary amines such as triethylamine and tri-n-propylamine, secondary amines such as diethylamine and di-n-propylamine, ethylamines, primary amines such as n-propylamine, cyclics such as morpholine Amine, N, N-dimethylaminoethyl (Meth) acrylate, N, N-diethylaminoethyl (meth) acrylate such as an amino group-containing (meth) acrylate, ammonium carbonate, ammonium salts, and the like. These may be used alone or in combination of two or more kinds.

In addition to the --COOM group, the hydrophilic polymer may have a polyoxyalkylene chain as a hydrophilic portion, and may contain an ethylenically unsaturated group so that it can act as a crosslinking agent. In addition to the hydrophilic polymer as the hydrophilic polymer in the present invention, for example,
Hydrophilic group such as hydroxyl group, amine group, sulfonic acid group and /
Alternatively, a polymer having a polyoxyalkylene chain may be used in combination. Incidentally, the content rate of the hydrophilic polymer in the entire composition, considering the water-based developability and water-based ink resistance,
5 to 50% by weight, particularly 7 to 40% by weight are preferable.

As the hydrophobic polymer used in the present invention, two or more kinds of hydrophobic polymers having different affinities with the hydrophilic polymer are used. The higher affinity with the hydrophilic polymer means that the affinity between the hydrophobic polymer and the affinity polymer is higher due to the interfacial tension. That is, it can be mentioned that the wettability is good and the van der Waals force, the hydrogen bonding force, the charge transfer force, the ionic bonding force, etc. act between the hydrophobic polymer and the hydrophilic polymer. Furthermore, when the hydrophobic polymer and the hydrophilic polymer have a common molecular structure in each polymer structure, for example, one or more selected from a conjugated diene, an olefin, a polyolefin, a polyether, an unsaturated carboxylic acid residue, and a halogen atom. However, the present invention is not limited thereto.

As the hydrophobic polymer used in the present invention, specifically, for example, a polymer obtained by polymerizing a conjugated diene hydrocarbon or a polymer obtained by polymerizing a conjugated diene hydrocarbon and a monoolefin unsaturated compound is obtained. Examples thereof include copolymers and elastomers containing a specific amount of chlorine. As the conjugated diene hydrocarbon, 1,3-butadiene, isoprene, chloroprene and the like are used. The conjugated diene hydrocarbons may be used alone or in combination of two or more. Examples of the monoolefin unsaturated compound include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, acrylamide, and methacrylic acid ester. used.

Examples of the polymer obtained by polymerizing the conjugated diene hydrocarbon or the copolymer obtained by polymerizing the conjugated diene hydrocarbon and the monoolefin unsaturated compound include a butadiene polymer, an isoprene polymer, Chloroprene polymer, styrene-butadiene copolymer, styrene-
Isoprene copolymer, styrene-chloroprene copolymer, acrylonitrile-butadiene copolymer, acrylonitrile-isoprene copolymer, acrylonitrile-chloroprene copolymer, methyl methacrylate-butadiene copolymer, methyl methacrylate-isoprene copolymer ,
Methyl methacrylate-chlorobrene copolymer, methyl acrylate-butadiene copolymer, methyl acrylate-isoprene copolymer, methyl acrylate-chloroprene copolymer, acrylonitrile-butadiene-styrene copolymer, acrylonitrile-isoprene-styrene Examples thereof include copolymers and acrylonitrile-chloroprene-styrene copolymers.

The elastomer containing a specific amount of chlorine is a polymer having a chlorine content of 50 to 10% by polymerization and a glass transition temperature (hereinafter referred to as Tg) of 5 ° C. or less,
For example, in the case of a monomer containing a chlorine atom, or from copolymerization with another monomer capable of copolymerizing with a monomer containing a chlorine atom. It can also be obtained by reacting chlorine or an active substance containing chlorine with a polymer containing no chlorine atom. Specifically, the following can be mentioned. Epichlorohydrin polymer, epichlorohydrin-ethylene oxide copolymer, epichlorohydrin-propylene oxide copolymer and / or epichlorohydrin rubber which is a copolymer of these and acrylic glycidyl ether (Epichromer manufactured by Osaka Soda Industry Co., Ltd., Goodvich Co., Ltd.)
HYDRIN, ZECHON GECHRON, Zeosvan, Hercules KK MERCLIB), chlorinated polyethylene (Showa Denko KK, Erasren, Osaka Soda Kogyo KK)
Made, Daiso rack, made by Hoechst Co., HORTALITZ, Do
w Chemical manufactured DOWCPE), vinyl chloride copolymer, vinyldene chloride, chlorinated polypropylene, chlorinated ethylene-propylene glycol, and the like. These polymers may be used alone or in combination of two or more kinds. The chlorine content of the polymer is from 10 to 50% by weight, preferably from 15 to 40% by weight, and if it deviates from this range, the flexibility is impaired and the thermal stability deteriorates, resulting in a photosensitive resin composition. Is too hard, and coloring tends to occur, which is not preferable. Since the conjugated diene hydrocarbon polymer containing a chlorine atom or its copolymer contains a carbon unsaturated bond in its main chain, it has a drawback that chemical stability such as weather resistance is inferior to that of a saturated bond alone. Further, since the physical properties of the photosensitive resin composition after light irradiation largely depend on the properties of the hydrophobic polymer in the present invention, it is preferable that the hydrophobic polymer is essentially a rubber elastic body. Therefore, its Tg needs to be 5 ° C. or lower, and particularly preferably −10 ° C. or lower.

The cross-linking agent according to the present invention is characterized by having a structure capable of polymerizing with actinic rays and having a low affinity for the hydrophilic polymer and the hydrophobic polymer having a high affinity for the hydrophilic polymer. To do. An ethylenically unsaturated compound can be mentioned as such a crosslinking agent. An ethylenically unsaturated compound is a compound containing at least one terminal ethylenic group, and this compound is capable of forming a high molecular polymer by free radical initiated chain growth addition polymerization. Suitable ethylenically unsaturated compounds are unsaturated esters of polyols, especially such esters with α-methylenecarboxylic acids, such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, glycerol diacrylate, 1 ，
3-Propanediol di (meth) acrylate, 1,4
-Butanediol di (meth) acrylate, 1,2,4
-Butanetriol tri (meth) acrylate, 1,4
-Cyclohexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate diallyl phthalate, fumaric acid diethyl ester, maleic acid dibutyl ester, etc., and also N-methylmaleimide, N-ethylmimide, N-laurylmaleimide, etc. N-substituted maleimide compounds, oligonitriles, butadiene di (meth) acrylates, oligonitriles, urethane (meth) acrylates, oligourethane di (meth) acrylates, oligobutadiene di (meth) acrylates and other oligo (meth) acrylates. ,
These may be used alone or in combination.

The content of the cross-linking agent in the composition is preferably 1 to 50% by weight, and if it is less than 1% by weight, the photopolymerizability is impaired, and no image remains after development. On the other hand, if it is more than 50% by weight, the shape characteristics will be impaired. Further, the plate after irradiation with light becomes hard and brittle, which makes it unsuitable as a plate material for flexographic printing, which is not preferable. More preferably 5 to 4
0% by weight.

Examples of the photopolymerization initiator used in the present invention include benzophenones, benzoins, acetophenones, benzyls, benzoin alkyl ethers, benzyl alkyl ketals, anthraquinones, thioxanthones and the like. In particular,
Benzophenone, chlorobenzophenone, benzoin, acetophenone, benzyl, benzoin, methyl ether, benzoin ethyl ether, benzoin.
Inpropyl ether, benzoin isobutyl ether, benzyl dimethyl ketal, benzyl diethyl ketal, benzyl diisopropyl ketal,
Examples include anthraquinone, 2-chloroanthraquinone, thioxanthone, and 2-chlorothioxanthone. These are preferably contained in the composition in an amount of 0.01 to 5% by weight. If it is less than 0.01%, the photopolymerization initiation ability is hindered,
When it is more than 5%, the curing depth cannot be obtained by the ordinary light, and the image is apt to be chipped due to development, which is not preferable. More preferably, it is 0.1 to 3% by weight.

Next, a method for producing the composition of the present invention will be described below with reference to the drawings. 1, 2 and 3 are schematic views showing an example of an apparatus used in the manufacturing method of the present invention. The apparatus shown in FIG. 1 supplies feeders 1 and 2 capable of continuously and quantitatively supplying two kinds of hydrophobic polymers which are solid raw materials in the composition, a pump 3 which supplies an organic solvent, and a crosslinking agent which is a liquid. A kneading machine 6 is connected to a pump 4 for supplying the hydrophilic polymer and a pump 5 for supplying a hydrophilic polymer.

Here, the kneading machine 6 is a single-screw or multi-screw extruder and has a charging port arranged so that various raw materials can be charged separately. Further, the screw is composed of a kneading disk having a large kneading effect and a screw disk having a transporting effect in order to knead each raw material and atomize the composition.

Further, FIG. 2 shows a case where the raw materials are collectively charged from the charging port, and each of the devices 1 to 6 is the same equipment as in FIG.

In FIG. 3, kneading tans 7, 8 and 9 having stirring blades for relatively slowing the sinking speed of the kneaded material and gear pumps 10, 11 and 12 capable of adjusting the flow rate are arranged in series.

[0024]

By continuously installing a single-screw or multi-screw extruder or tank as described above, the phase structure of the composition having a high viscosity and difficult to be kneaded can be made into fine particles, and further continuous. It is possible to manufacture with extremely high production efficiency.

[0025]

EXAMPLES The method of the present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Example 1 The apparatus shown in FIG. 1 was used, a twin-screw extruder was used as a kneader, and the screw diameter was 48 as the specifications of this twin-screw extruder.
mm, screw length / diameter ratio (L / D) of 64, of which the mixing zone of the hydrophobic polymer and organic solvent is about L / D = 38, and the mixing zone of the cross-linking agent is about L / D =
10, moreover, the mixing zone of hydrophilic polymer is about L / D =
Sixteen different charging methods were adopted. Among these, a suitable combination of a kneading disk and a screw disk was used for each zone.

Chlorinated polyethylene 11.2 kg / h and butadiene rubber 3.4 k from feeders 1 and 2, respectively.
g / h, Toluene 16.2 kg / h from pump 3, Pump 4 butadiene oligoacrylate 6.6 kg /
h, the hydrophilic polyurethane acrylate, tetrahydrofuran, and water from the pump 5 are 28.4: 34.6:
The mixed solvent adjusted at a ratio of 38 was charged into a twin-screw extruder at 9.9 kg / h, the cylinder temperature was 50 ° C., and the rotation number per minute was 5
A photosensitive resin composition solution was obtained by kneading at 00 revolutions and transferring.

After that, toluene / water and tetrahydrofuran were deaerated using a heating kneader to obtain a photosensitive resin composition. The obtained photosensitive resin composition was laminated using a polyester film support and a polyester cover film to obtain a printing plate material having a thickness of 3 mm.

Next, the uppermost polyester film of the obtained printing plate material was peeled off, a negative film was adhered to the photosensitive resin composition, exposed with a mercury lamp, and then the negative film was removed to obtain an alkylnaphthalenesulfonic acid. Development was carried out with a brush in neutral water containing 2% by weight of soda at 40 ° C. for 15 minutes to obtain a printing plate material having a relief depth of 1.2 mm. When the printing plate material thus obtained was observed under a microscope, it was composed of particles of 0.5 to 3 μm.

[0030]

According to the production method of the present invention, the resin in the dispersed phase is finely divided into fine particles by phase separation, so that it is possible to produce a printing plate material that enables more vivid printing than in the past. Instead, the conventional batch-type equipment required two types of equipment, a composition production equipment such as a tank and a particle production equipment such as a concentrator, but since it can be produced with only one type of equipment, continuous production is possible. Since it can be produced, it contributes greatly to industrial use because it improves production efficiency.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a manufacturing apparatus used in the manufacturing method of the present invention, which has charging ports for charging various raw materials separately.

FIG. 2 is a schematic view showing an example of a manufacturing apparatus used in the manufacturing method of the present invention, which has a charging port for charging various raw materials all at once.

FIG. 3 is a schematic view showing an example of a manufacturing apparatus used in the manufacturing method of the present invention.

[Explanation of symbols]

 1, 2: Feeder 3-5: Pump 6: Kneader 7-9: Kneading tank 10-12: Pump

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location G03F 7/004 503 G03F 7/004 503 7/032 7/032 (72) Inventor Toshiyuki Kita Shiga Prefecture 2-1-1 Katata, Otsu City, Toyobo Co., Ltd. Research Institute (72) Inventor Shinichi Tanaka 2-chome, Dojimahama 2-chome, Kita-ku, Osaka Toyobo Co., Ltd.

Claims (3)

[Claims] 1. A photosensitive resin composition having a disperse phase mainly composed of a hydrophobic polymer and a hydrophilic polymer and having an average particle size of less than 10 μm, and a continuous phase mainly composed of a crosslinking polymer and a hydrophobic polymer different from the hydrophobic polymer. In the method for obtaining, a hydrophilic polymer, two or more kinds of hydrophobic polymers having different affinities with the hydrophilic polymer, a crosslinking agent, a photopolymerization initiator and a solvent compatible with the hydrophilic polymer are blended, A method for producing a photosensitive resin composition, characterized in that it is phase-separated during melt mixing and transfer. 2. A hydrophobic polymer and a hydrophilic polymer present in the dispersed phase have one or more common structures selected from conjugated dienes, olefins, polyolefins, polyethers, unsaturated carboxylic acid residues and halogen atoms. Alternatively, the method for producing the photosensitive resin composition according to claim 1, which contains atoms. 3. A hydrophobic polymer in an amount of 20% by weight to 80% by weight, a hydrophilic polymer in an amount of 5% by weight to 50% by weight and a crosslinking agent in an amount of 1% by weight to 50% by weight. The method for producing the photosensitive resin composition according to claim 1.