JP3266357B2 - Developer composition for flexographic printing plates - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer composition for a flexographic printing plate, and more particularly to a developer having a very good developability, whereby a relief image having excellent reproducibility can be formed, and excellent long-term storage stability. The present invention relates to a developer composition for flexographic printing plates, which has high safety and is preferable in terms of work hygiene and environmental hygiene.

[0002]

2. Description of the Related Art Conventionally, photosensitive resin compositions have been used to form flexographic printing plates. This photosensitive resin composition is composed of a thermoplastic elastomer, a photopolymerizable unsaturated monomer, a photopolymerization initiator and the like. For example, Japanese Patent Publication No. 51-43374, Japanese Patent Publication No. 59-22219 and the like. It is described in detail.

In order to prepare a flexographic printing plate using the above photosensitive resin composition, the printing plate surface coated with the photosensitive resin composition is irradiated with actinic rays through a mask having a desired pattern. Then, using a developing solution, the unirradiated portion of the actinic ray is dissolved or swelled and removed to complete a flexographic printing plate.

As the developer, halogenated hydrocarbons such as chloroform, trichloroethane, trichloroethylene and tetrachloroethylene, and mixtures of these with alcohols are used.

[0005]

However, the above-mentioned developer has high volatility because it is composed only of an organic solvent, and has a problem in terms of work hygiene and environmental hygiene because it contains chlorine. . Further, when the flexographic printing plate is developed with the above developer, there is a problem that the unexposed portion is easily swelled.

To solve the above problem, a developer composition in which an organic solvent and water are dispersed and mixed is disclosed in, for example, JP-A-2-26.
No. 7557, and the like. However, there is a problem that the stability with time is poor and the organic solvent phase and the aqueous phase are easily separated.

The present invention has been made to solve the above problems, and has excellent developability, high stability over time,
Moreover, it is an object of the present invention to provide a developer composition for flexographic printing plates which has high safety and has no problem in working hygiene and environmental hygiene.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a developer composition for a flexographic printing plate of the present invention comprises an organic solvent,
From water and water-in- oil emulsions containing emulsifiers
In the flexographic printing plate developer composition, the emulsifier contains a nonionic surfactant having an HLB value of 9.0 or less, which is a value indicating a balance between a hydrophilic group and a lipophilic group in a surfactant molecule. and also see contains an anionic surfactant and at least one surfactant of the nonionic surfactant the HLB value is more than 9.0, further wherein the emulsifier, the
0.01% by weight or more and 10% by weight or less in the developer composition
Non-ion containing HLB value of 9.0 or less
Of surfactants in the total emulsifier is 10% by weight
As described above, the content is 99.95% by weight or less .

The HLB value (Hydrophile-Lipophi
le Balance) is a value that indicates the balance between hydrophilic groups and lipophilic groups in surfactant molecules proposed by Griffin. This HLB value can be determined experimentally by comparing the emulsifying power of various surfactants. For the nonionic surfactant according to the present invention,
It can be obtained from the equation of Equation 3 and the like.

[0010]

(Equation 1)

(Equation 2)

(Equation 3)

The above formula (1) is used to determine the HLB value from the saponification value of the ester and the acid value of the fatty acid when the surfactant is an ester of a polyhydric alcohol and a fatty acid. In addition, the equation (2) is for obtaining the HLB value using the weight fraction of the oxyethylene group and the weight fraction of the polyhydric alcohol group when a clear saponification value is difficult to obtain,
Further, the expression of Equation 3 is obtained by using the weight fraction of oxyethylene groups when only polyoxyethylene groups are included as hydrophilic groups.

When the HLB value is known, the relationship between the HLB value and the use of the surfactant (solubiliser, detergent, W / O type (water-in-oil type) emulsifier, etc.) or the HLB value and the solubility Are known, so that the selection of the surfactant is facilitated. The details of the HLB value are described in “Surfactant Handbook”, edited by Kogyo Tosho Publishing Co., Ltd., Etsushi Takahashi, Yoshiro Namba, Motoo Koike, and Masao Kobayashi (1970), pages 178 to 189.

The present inventors have conducted intensive studies in order to solve the above-mentioned problems of the prior art, and as a result, by using a surfactant having a specific HLB value as an emulsifier in the developer composition, it has been developed. The liquid composition has a very stable W / O
It has been found that a mold emulsion is formed, and that the solubility of the photosensitive resin is also remarkably improved, thereby completing the present invention.

The surfactant component constituting the emulsifier according to the present invention is as follows. (A) Nonionic surfactant having an HLB value of 9.0 or less. (B) Nonionic surfactants having an HLB value of more than 9.0. (C) an anionic surfactant. The component (a) is essential among the above surfactants, and has an effect of improving the storage stability of the developer composition. Also,
Both the component (b) and the component (c) may be contained, or either one of them may be contained. These components (b) and (c) have the effect of improving the storage stability of the developer composition.

[0015] The emulsifier comprising the above components is contained in the developer composition of the present invention and mixed well, so that the organic solvent and water, which are the components of the developer composition, are converted to W / O.
It forms an emulsion of the type, i.e. of the type in which water drops are suspended in an organic solvent. When the W / O emulsion thus formed is used as a developer composition, it is compared with an O / W (oil-in-water) emulsion (an emulsion in which oil droplets of an organic solvent are suspended in water). As a result, since the organic solvent in the developer composition has good contact with the photosensitive resin composition to be developed, the developing ability is improved. Further, since the surfactant is combined as described above, the stability with time is high, and the emulsion does not separate in a short period of time.

When the components (a) and (b) are used as a mixture, their HLB values are a and b, and x,
The HLB value when mixed at the ratio of y can be obtained from the following formula: HLB = (ax + by) / (x + y). If the HLB value at this time can take a value of about 2 to 9, the developability is improved. It has been found that a developer composition for a flexographic printing plate which is good and has high stability over time can be obtained.

The above HLB value is 9.0 or less, but is particularly preferably 2.0 or more and 6.0 or less. This HLB
When the value exceeds 9.0, the emulsion becomes an O / W type and the developing ability is reduced.

The emulsifier is contained in the developer composition in an amount of 0.0
1% by weight or more and 10% by weight or less, further 0.03% by weight
Preferably, the content is 3% by weight or less. When the content of the emulsifier is less than 0.01% by weight, the storage stability of the obtained developer composition is deteriorated, and it becomes difficult to supply a developer composition having a constant quality. On the other hand, when the mixing ratio of the developer composition exceeds 10%, the developing performance is lowered and it is uneconomical.

The proportion of the component (a) in the total emulsifier slightly varies depending on the composition of the photosensitive resin composition to be developed, but is not less than 10% by weight and not less than 99.95% by weight.
The content is more preferably 50% by weight or more and 80% by weight or less. When the proportion of the component (a) is less than 10% by weight, the developability decreases, and when it exceeds 99.95% by weight, sufficient storage stability cannot be obtained.

Examples of the nonionic surfactant having an HLB value of 9.0 or less as the component (a) include hexamethylene glycol monostearate, tetraethylene glycol monolaurate, tetramethylene glycol monooleate, and tetraethylene. Glycol monostearate, diethylene glycol monolaurate, diethylene glycol monooleate, diethylene glycol monostearate, glycerol monostearate, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan monosesquioleate Sorbitan tristearate, sorbitan trioleate and the like.

The HLB value of the component (b) of 9.
Examples of the nonionic surfactant exceeding 0 include polyoxyethylene (degree of polymerization of 5 or more) monooleate, polyoxyethylene (degree of polymerization of 4 or more) tristearate, polyoxyethylene (degree of polymerization of 4 or more) trioleate, triethanol Examples thereof include amine oleate, polyoxyethylene (polymerization degree 9 or more) nonylphenol, and polyoxyethylene (polymerization degree 4 or more) sorbitan monolaurate.

Further, the anionic surfactant as the component (c) includes, for example, sodium salts of lauryl alcohol sulfate, sodium salts of octyl alcohol sulfate, ammonium salts of lauryl alcohol sulfate, and secondary carbon alkyl salts such as sodium alkyl sulfate. number 8-22 higher alcohol sulfate ester salts, fatty alcohol phosphoric ester salts such as sodium salt of ethyl alcohol phosphate ester, sodium salt of dodecylbenzenesulfonic acid, sodium salt of isopropyl naphthalene sulfonic acid, meta-nitro benzene Nsu sulfone Alkyl aryl sulfonates such as sodium salt of acid, sulfonates of alkyl amide, dioctyl sodium sulfosuccinate, dihexyl sodium sulfosuccinate Sulfonic acid salts such as dibasic fatty acid esters such as esters.

As a component of the emulsifier according to the present invention, a cationic surfactant, an amphoteric surfactant or the like may be contained, if desired, in addition to the above-mentioned surfactants.

Examples of the organic solvent contained in the developer composition of the present invention include ethyl acetate, propyl acetate, butyl acetate, amyl acetate, benzyl acetate, 3-methoxybutyl acetate, 2-ethylhexyl acetate, cyclohexyl acetate. Carboxylic acid esters such as ethyl butyrate, isobutyl butyrate, isoamyl butyrate, isobutyl isobutyrate, ethylene glycol monobutyl acetate, butyl lactate, butyl levulinate, ketones such as ethyl butyl ketone, methyl isobutyl ketone, cyclohexanone, ethylene glycol mono Alkyls such as butyl ether, ethylene glycol benzyl ether, ethylene glycol monophenyl ether, benzyl alcohol, methylphenyl carbinol, n-amyl alcohol, and methyl amyl alcohol , Toluene, xylene, trimethylbenzene, methylethylbenzene, tetramethylbenzene, isopropylmethylbenzene, ethylbenzene, diethylbenzene, methylstyrene, ethylstyrene and other alkyl-substituted aromatic hydrocarbons, methylene dichloride, ethylene dichloride, monochlorobenzene, etc. Halogenated hydrocarbons, dimethylcyclohexane, trimethylcyclohexane, propylcyclohexane, methylethylcyclohexane, tetramethylcyclohexane, diethylcyclohexane, butylcyclohexane,
Examples thereof include cyclic aliphatic hydrocarbons such as ethyldimethylcyclohexane. These organic solvents may be used alone or in combination of two or more. Further, alcohols and the like may be mixed as needed.

The above organic solvent is usually added to the developer composition in an amount of 5
It is blended in a range of not less than 90% by weight, preferably not less than 10% by weight and not more than 70% by weight. If the amount is less than 5% by weight, the development time is prolonged and the development fatigue is undesirably increased. On the other hand, if the content exceeds 90% by weight, the working environment may deteriorate because the organic solvent is mainly used, which is not preferable in practical use.

It is preferable to use so-called soft water having a German hardness of 10 ° or less as water contained in the developer composition of the present invention. When so-called hard water having a German hardness of more than 20 ° is used, the photopolymerizable unsaturated monomers, which are one component of the photosensitive resin composition, are caused by calcium ions, magnesium ions, and the like contained in the hard water. Causes ionic crosslinking. The unsaturated monomer that has undergone ionic cross-linking is hardly soluble or insoluble in the organic solvent in the developer composition, and thus causes poor development or becomes a particulate insoluble material floating in the developer composition. As a result, the performance of the developer composition may be reduced.

The above hard water or German hardness of 10 ° to 20 °
When so-called intermediate water is used, it is possible to boil in advance to remove the above calcium ions, magnesium ions, etc. by precipitating them as carbonates, to remove them by an ion exchange method, or to use a water softener. is necessary.

As the water softener, for example, Na _{2
P 2 O 7, Na 5 P} 5 O 3, Na 5 P 3 phosphates O etc., Na ₂
Examples include polyphosphates such as O ₄ P (NaO ₃ P) PO ₃ Na ₂ and calgon. Also, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, hydroxyethylethylenediaminetriacetic acid, nitrilotriacetic acid, 1,2-diaminocyclohexanetetraacetic acid, 1,3-diamino-2-propanoltetraacetic acid, and the compounds of these compounds Aminopolycarboxylic acids such as potassium salts and sodium salts can also be used.

When such a water softener is added to the developer composition of the present invention, the preferred amount of addition depends on the amount of hard water used and the hardness, but is usually 0.01% by weight of the total amount of the developer composition. % Or more and 3% by weight or less.

In the developer composition of the present invention, conventionally known additives such as a chelating agent, an antifoaming agent, a dye, an acid and an alkali may be appropriately used in addition to the above-mentioned organic solvent, water and emulsifier. can do.

The photosensitive resin composition which can be developed using the developer composition of the present invention comprises a thermoplastic elastomer, a photopolymerizable unsaturated monomer, a photopolymerization initiator and the like as described above. . This thermoplastic elastomer is a polymer material having the same rubber elasticity at normal temperature as vulcanized rubber, and having the same flow characteristics as ordinary thermoplastic resin at high temperature, such as styrene, olefin, polyester, and polyurethane. A wide variety of types are known, such as those based on polyisoprene, 1,2-polybutadiene, vinyl chloride, and polyamide.

Of the above thermoplastic elastomers, those particularly preferred for flexographic printing plates are styrene-based thermoplastic elastomers. Specifically, styrene / butadiene / styrene block copolymers, styrene / isoprene /
Styrene block copolymers and hydrogenated products thereof.

[0033] The photopolymerizable unsaturated monomer is compatible with or can be mixed with the thermoplastic elastomer. Specifically, the photopolymerizable unsaturated monomer has at least one vinyl group. Polymerizable unsaturated monomer, for example, having 2 carbon atoms
An aliphatic or alicyclic diol having 10 to 10, particularly 2 to 6 carbon atoms, for example, ethylene glycol, triethylene glycol, hexanediol, cyclohexanediol and the like,
Diesters derived from ethylenically unsaturated carboxylic acids having 3 to 5 carbon atoms, such as acrylic acid and methacrylic acid, and triesters derived from triols and the unsaturated carboxylic acids, and further, polycarboxylic acids And the like.

Further, examples of the photopolymerization initiator include benzoin-based, benzophenone-based, and anthraquinone-based photopolymerization initiators.

The photosensitive resin composition is blended with a suitable amount of a cresol-based, phenol-based, hydroquinone-based thermal polymerization inhibitor, a pigment, a dye, a plasticizer, an antioxidant, a photodegradation inhibitor and the like. Sometimes.

Next, an example of a method for producing a flexographic printing plate using the developer composition of the present invention will be described. First, according to a known method, a photosensitive resin composition is prepared by dissolving the thermoplastic elastomer, a photopolymerizable unsaturated monomer, a photopolymerization initiator and various optional components used as desired in an organic solvent. . Then, the photosensitive resin composition is formed into a film or plate to remove the solvent, or by mixing with a roll mixer and forming into a film or plate by a hot press, for producing a flexo relief. A photosensitive resin layer is formed. Then, this photosensitive resin layer is pressed and integrated with a polyester film or plate such as polyethylene terephthalate, a steel plate, an aluminum plate or the like to form a flexographic printing plate material.

In order to prepare a flexographic printing plate relief, the plate material is irradiated with actinic rays such as ultraviolet rays through a desired mask pattern to selectively cure the photosensitive resin layer. Then, if the uncured portion of the photosensitive resin layer is washed away using the developer composition of the present invention, a relief for a flexographic printing plate having rubber elasticity can be obtained.

[0038]

The developer composition for flexographic printing plates of the present invention contains a nonionic surfactant having an HLB value of 9.0 or less as an emulsifier, and has an anionic surfactant and the aforementioned HLB value of 9.0.
, A W / O emulsion can be formed, and the stability over time is improved.

[0039]

EXAMPLES Examples and comparative examples based on the present invention will be shown below. Example 1 A liquid having the following composition was mixed with a homomixer at a rotational speed of 7000 r.
The mixture was mixed at pm for 5 minutes to prepare a developer composition for a flexographic printing plate of a W / O emulsion. Petroleum-based aromatic solvent (“Headazole R-150”: manufactured by Morphyl Petrochemical) 38.7% by weight Water (German hardness 5 °) 60.0 〃 Emulsifier 1.3 〃 (a) Component Nonionic surfactant [criserine Fatty acid ester: HLB value = about 3] (“CR-ED”: Sakamoto Yakuhin Kogyo) 1.0% by weight (c) component Anionic surfactant [Alkylbenzene Sulfonate Sorter] (“Monocan Y-500”: 0.3 〃

On the other hand, a photosensitive resin having the following composition
A plate material for a flexographic printing plate was prepared by pressure bonding on a polyethylene terephthalate film with a thickness of m. 100 parts by weight of thermoplastic elastomer [Styrene polyene block copolymer] ("Taffene AQ": manufactured by Asahi Kasei) Plasticizer [liquid polybutadiene] ("Nisso PB-1000": manufactured by Nippon Soda) 50 〃 Photopolymerizable unsaturated unit (Trimethylolfluorotriacrylate) (“Aronix M-309”: manufactured by Toagosei) 5 〃 Photopolymerization initiator [phenoxymethyl ketal] (“Dilka Cure 651”: manufactured by Tikka Ikki) 2 〃 Polymerization inhibitor [2,6- (Tert-butyl-4-human-hydroxytoluene) 0.05 〃 Organic solvent toluene 100 〃 Methyl ethyl ketone 50 〃

Next, the plate material was irradiated with ultraviolet rays using a mask pattern having an independent line having a width of 0.1 mm to partially cure the photosensitive resin of the plate material. Then, this plate material was immersed in the developer composition, brushed and developed.

The developer composition of this example was found to be able to completely wash away the uncured photosensitive resin by performing the above-mentioned brushing for only 2 minutes, and it was found that the "development performance" was high. Further, in the prepared relief for flexographic printing plate, the independent line having a width of 0.1 mm was reproduced in a perfect form, and the “plate making reproducibility” was excellent.

Further, the developer composition was left at room temperature for one week, and it was observed whether or not the emulsion separated. As a result, there was no change, and it was found that the "time stability" of the developer was excellent. Do you get it.

Examples 2 to 4 A developer composition was prepared in the same manner as in Example 1 except for the following, and the same evaluation as in Example 1 was performed. Example 2 The component (c) was not used, and the component (b) was a nonionic surfactant [polyoxyethylene alkyl allyl ether: HLB value: 15.5] ("Emulken 920", manufactured by Kao) 0.3 weight%
It was used. Example 3 0.1% by weight of the same nonionic surfactant as in Example 2 was used as the component (b), and 0.2% by weight of the same anionic surfactant as in Example 1 was used as the component (c). Example 4 Without using the component (c), a nonionic surfactant [nonylphenylethoxylate: HLB value = 10] was used as the component (b).
(“ATEDUCATOL NP-650”: manufactured by Asahi Denka Kogyo) 0.3% by weight was used.

Examples 5 and 6 A developer having the following composition was prepared in the same manner as in Example 1, and the same evaluation as in Example 1 was carried out. Example 5 Petroleum aromatic solvent (same as in Example 1) 35.5% by weight Water 55.0 {Emulsifier 9.5} Component (a) Nonionic surfactant [polyoxyethylene nonyl phenyl ether: HLB = 8 9.9] (“Emulken 904”: manufactured by Kao) 9.0〃 (b) component Same as in Example 4 0.5〃 (c) component Not used

Example 6 Petroleum aromatic solvent (same as in Example 1) 40.0% by weight water 60.0 {emulsifier 0.013} (a) component Same as in Example 1 0.008% (b) component Same as in Example 2 0.002〃 (c) Component Same as in Example 1 0.003〃

The developer compositions of the above examples were good in both developing performance and reproducibility of plate-making products, and also had sufficient stability over time. The results are shown in Table 1 below together with Example 1.

[0048]

[Table 1]

In the "Development performance" column of "Evaluation" in Table 1, "O" indicates that development was possible by brushing for 2 to 3 minutes, and "X" indicates that development required a considerably long time. Further, in the column of “reproducibility of plate making”, ○ indicates that the 0.1 mm independent line is completely reproduced, x indicates swelling of the resin,
The independent lines are in contact with each other due to deformation of the pattern. Further, in the column of "Stability over time", ○ indicates that the emulsion state did not change even after being left for one week, Δ indicates that the emulsion was separated in about 30 minutes after preparation, and X indicates that no emulsion was formed.

Comparative Examples 1 to 4 A developer composition was prepared in the same manner as in Example 1 except for the following, and the same evaluation as in Example 1 was performed. Comparative Example 1 The amount of the organic solvent was increased without using the component (c). Comparative Example 2 The component (a) was not used, and the amount of the organic solvent was increased accordingly. Comparative Example 3 A nonionic surfactant [polyoxyethylene hydrogenated castor oil: HLB value =
12.5] ("Emanone CH-40": manufactured by Kao) 1% by weight. Comparative Example 4 1% by weight of the nonionic surfactant of Example 4 was used as the component (b) instead of the component (a). The component (c) was not used, and the amount of the organic solvent was increased accordingly.

The results are shown in Table 1. Comparative Example 1
Then, the emulsion separated in about 30 minutes after the preparation. In the other comparative examples, no emulsion was formed, and both the developing performance and the reproducibility of the plate were poor.

[0052]

As described above, the developer composition for flexographic printing plates of the present invention, as the emulsifier, has an HLB value indicating a balance between a hydrophilic group and a lipophilic group in a surfactant molecule. Contains 9.0 or less of a nonionic surfactant, so that a W / O type emulsion form is obtained, and the developing performance is improved. Further, since it contains at least one of an anionic surfactant and a nonionic surfactant having an HLB value of more than 9, the stability with time is also excellent.

Further, the emulsifier is added in an amount of 0.1% in the developer composition.
Not less than 01% by weight and not more than 10% by weight, and
When the proportion of the nonionic surfactant having a B value of 9.0 or less in the emulsifier is 10% by weight or more and 99.95% by weight or less, the developing performance and the stability with time are further improved. .

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-267557 (JP, A) JP-A-60-6947 (JP, A) JP-A-4-285967 (JP, A) JP-A-61- 175636 (JP, A) JP-A-5-188602 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03F 7/32 G03F 7/00 502

Claims (1)

(57) [Claims] An oil containing an organic solvent, water, and an emulsifier.
In the developer composition for a flexographic printing plate comprising a water-in-water emulsion , the emulsifier is a nonionic having an HLB value of 9.0 or less, which is a value indicating a balance between a hydrophilic group and a lipophilic group in a surfactant molecule. A surfactant, and at least one of an anionic surfactant and a nonionic surfactant having an HLB value of more than 9.0.
And the emulsifier is added in an amount of 0.01% by weight in the developer composition.
% Or more and 10% by weight or less, and the HLB value is
Non-ionic surfactants of 9.0 or less account for all emulsifiers.
Between 10% and 99.95% by weight
A developer composition for a flexographic printing plate.