JP3483025B2 - Water-developed photosensitive flexographic printing plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION The present invention relates to a method for improving image reproducibility.
Water-developable photosensitive flexographic printing plate. [0002] 2. Description of the Related Art Conventionally, flexographic printing has been based on aqueous inks.
Use low-viscosity inks containing alcohol or alcohol.
Environmentally friendly, and the printing press is simple,
It is widely used because of its high
Key printing, planographic printing, gravure printing, etc.
In all cases, the image reproducibility is inferior.
Is desired. Printing plates used for flexographic printing
Is made of a material having rubber elasticity, and the thickness of the plate is 1 m
It is characterized by being as thick as m to 7 mm. For this reason, printing
Where the printing plate contacts the substrate and transfers ink.
If the printing plate is deformed, the printed image
The problem of dot gain
Have. For printing plates, the thickness of the plate uses oil-based ink.
Images are thicker than topographic printing plates and planographic printing plates.
The light necessary for the formation is not sufficiently transmitted to the inside. this
Therefore, there is a problem that image reproducibility is not good. [0004] SUMMARY OF THE INVENTION The present invention is directed to a flexo stamp.
Excellent image reproducibility in printing and low dot gain
The challenge was to provide flexographic printing plates with good printability.
To do. [0005] Means for Solving the Problems The present inventors have achieved the above object.
As a result of intensive research to achieve this, the printing plate surface and
By making a difference in the internal dynamic hardness,
To provide a photosensitive flexographic printing plate with excellent image reproducibility
Made it possible. That is, the present invention provides a water-developable photosensitive
In flexographic printing plates, a halftone dot surface with a density of 50% or less
Dynamic hardness (A) and 100% density solid surface
Dynamic hardness (B) ratio (A) / (B) is 1.1
Water-developable photosensitive flexographic seal characterized by the above.
It is a printing plate. [0006] DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
You. Dyna of halftone dot surface having a concentration of 50% or less in the present invention
Mick hardness is defined as the depth from the outermost surface of halftone dots with a concentration of 50% or less.
Dynamic hardness at 0 to 10 μm
100% solid surface dynamic hardness is 10%
At a depth of 0 to 10 μm from the outermost surface of the 0% solid portion.
It means the dynamic hardness, and in the present invention
Dynamic hardness is Shimadzu review Vol.50.No3 (1993.12) 321
Provides information on the strength characteristics of the sample surface as described in
Shimadzu Dynamic Ultra Micro Hardness Tester D
This is the hardness measured by UH201. In the present invention, a dot table having a concentration of 50% or less is used.
Dynamic hardness of surface (A) and 100% density solid part
The ratio (A) / (B) of the surface hardness (B) is 1.1 or more
When printing, the solid ink is well transferred at low printing pressure.
Is printed and printed at the same time
Therefore, a well-balanced printed matter can be obtained as a whole. one
On the other hand, the ratio (A) / (B) of the dynamic hardness is 1.
If it is less than 1, the halftone dot portion is broken in printing and a clear mark is obtained.
It is not preferable because a printed matter cannot be obtained. In the present invention, the dynamics of the halftone dot surface
Ratio of hardness (A) to dynamic hardness of solid surface (B)
The method of setting the ratio (A) / (B) to 1.1 or more is based on the plate composition
-Island-type phase-separated structure with phase distribution
The difference in the solubility of the cross-linking component in each sea-island component.
To give a difference in hardness by using
It is not limited to this. In forming the sea-island type phase structure,
When the composition is a non-crosslinked product, for example, the literature “Polymer
Alloy ": edited by The Society of Polymer Science, Tokyo Chemistry Dojin P22 (198
As described in 1), relatively low viscosity and flow
The easy-to-use composition takes the phase structure of the sea. Also, the structural composition is non-
In the case of a bridge and a crosslinked product, the crosslinked product does not dissolve in the non-crosslinked product.
Therefore, a non-crosslinked material with low viscosity and fluidity
Take a phase structure. In the sea-island structure, the outermost surface of the printing plate is marine
Component becomes the main component, and the composition of the sea component can be localized
Becomes In the present invention, the crosslinking density of the outermost surface of the printing plate is
The high sensitivity increases the sensitivity, which is higher than conventional flexographic printing plates.
High image reproducibility can be obtained
It seems to be. As mentioned above, the present invention has the sea-island structure.
Flexographic printing plates consist of a non-crosslinked product and a crosslinked product.
May be constituted by phase separation of
You. Explained below when it is composed of non-crosslinked and crosslinked products
I do. Cross-linked particulate hydrophilic or water-swellable elast
The tomer is disclosed in Japanese Patent Application Laid-Open No. Hei.
Of partial internal crosslinking obtained by radical emulsion polymerization
Examples are given. This partially internally crosslinked copolymer is an aliphatic copolymer.
40-95 mol% of at least two diene monomers and at least two
0.1 to 10 mol% of a compound having an addition-polymerizable group
Radical polymerization of a monomer mixture containing
Obtained by Aliphatic conjugate as the copolymer component
Examples of diene monomers include butadiene, isoprene,
Dimethyl butadiene, chloroprene and the like can be mentioned.
Examples of α, β-ethylenically unsaturated carboxylic acids include
Lylic acid, maleic acid, fumaric acid, tetraconic acid, pro
And tonic acid. At least two addition polymerizable
Examples of compounds having various groups include trimethylol pro
Pandi (meth) acrylate, trimethylolpropane
Tri (meth) acrylate, divinylbenzene, ethyl
Glycol di (meth) acrylate, pentaerythri
Tall tetra (meth) acrylate, 1,4-butanedi
All-di (meth) acrylate, 1,6-hexanedioxide
Glue (meth) acrylate and the like. Note that α,
The carboxyl group of β-ethylenically unsaturated carboxylic acid is a salt
May be salified by compounds containing basic nitrogen atoms
Preferred basic nitrogen compounds are N, N-di
Methylaminopropyl (meth) acrylamide, N, N
-Dimethylaminoethyl (meth) acrylamide, N,
N-dimethylaminoethyl-N '-(meth) acryloyl
Luca-bamate, N, N-dimethylaminoethoxyethoxy
Ethanol, N, N-dimethylaminoethoxyethyl
(T) acrylate and the like. Cross-linked particulate hydrophilic or water-swellable
Another example of an elastomer is disclosed in JP-A No. 2-17 / 1990.
No. 5702, etc.
Underground. Core shell microgel here
Binder has 10% or less crosslinking
An aqueous system consisting of a core and an acid-modified copolymer
With an external shell that is not cross-linkable
A particle having two regions. Core-forming monomers
Methyl methacrylate, ethyl acrylate
G, methacrylic acid, butyl methacrylate, ethyl
Methacrylate, glycidyl methacrylate, styrene
Len and allyl methacrylate, as well as crosslinkers
Acrylate as ethylene glycol, ethylene glycol
Diol methacrylate, tetramethylene glycol di
Acrylate, trimethylolpropane triacrylate
And tetramethylene glycol dimethacrylate
I can do it. On the other hand, the acid-modified copo
N-butyl modified with methacrylic acid
Acrylates are preferred. Core-shell microgel vine
Is usually made by emulsion polymerization using these monomers.
Built. In addition to the above, crosslinked or non-crosslinked type particles
As the hydrophilic or water-swellable elastomer,
Latex described in JP-A-6-289610
Examples are given. This latex is a monoolefin type
From unsaturated monomers and unsaturated monomers with hydrophilic functional groups
Obtained by emulsion polymerization of a monomer mixture consisting of
You. Monoolefinically unsaturated monomers include methyl
Acrylate, ethyl acrylate, n-butyl acryle
, 2-ethylhexyl acrylate, n-octyl
Acrylate, dodecyl acrylate, methoxyethyl
Acrylate, ethoxyethyl acrylate, cyanoe
Tyl acrylate, hydroxyethyl acrylate,
Acrylic esters such as doxypropyl acrylate
And methacrylic esters thereof.
Other monoolefinically unsaturated monomers include styrene
, Acrylonitrile, vinyl chloride, ethylidene norbo
Runene, propenyl norbornene, dicyclopentadie
And the like. In some cases, 1,3-pig
Diene, isoprene, chloroprene, 1,3-pentadi
Conjugated diene monomers such as ene may be used,
For this purpose, a polyfunctional vinyl compound may be introduced. Hydrophilic
Carboxyl group, phosphate group, phosphate group
Stele group, sulfonic acid group, hydrohistyl group
However, from the viewpoint of washability, phosphate ester groups are more preferable.
New The above-mentioned unsaturated monomer having a phosphate group,
Is ethylene phosphate (meth) acrylate, phosphoric acid
Limethylene (meth) acrylate, propylene phosphate
(Meth) acrylate, tetramethylene phosphate (meth)
Acrylate, phosphoric acid (bis) ethylene (meth) acrylic
Rate, (bis) trimethylene (meth) acrylic acid phosphate
(Bis) tetramethylene (meth) acrylic acid phosphate
Sheet, diethylene glycol phosphate (meth) acrylate
G, phosphoric acid (bis) triethylene glycol (meth) a
Crylate, phosphoric acid (bis) polyethylene glycol
(Meth) acrylate and the like. The present invention comprises a non-crosslinked product and a crosslinked product.
The case in which it is performed will be described below. Non-crosslinked type particulate parent
Examples of aqueous or water-swellable elastomers include those disclosed in
Hydrophobic polymer described in 3-72353 and the like
Based on and hydrophilic polymer based
Can be mentioned. Make up the particles
As a hydrophobic polymer, conjugated diene hydrocarbons are polymerized.
Polymer or conjugated diene-based hydrocarbon
Copolymerization obtained by polymerizing olefinic unsaturated compounds
And polymers not containing conjugated diene hydrocarbons, and the like.
It is. A hydrophilic polymer mainly forming a phase surrounding the particles;
-Include hydroxyl, carboxyl, amino, sulfo
Hydrophilic groups such as phonic acid groups and / or polyethylene glycol
Examples include polymers having a recall chain. Forming a phase mainly composed of a hydrophobic polymer
A polymer obtained by polymerizing the conjugated diene hydrocarbon,
Or conjugated diene hydrocarbons and monoolefinic unsaturation
Examples of copolymers obtained by polymerizing compounds include
Tadiene polymer, isoprene polymer, chloroprene polymerization
Body, styrene-butadiene copolymer, styrene-isop
Styrene copolymer, styrene-chloroprene copolymer,
Rilonitrile-butadiene copolymer, acrylonitrile
-Isoprene copolymer, methyl methacrylate-butadiene
Copolymer, methyl methacrylate-isoprene copolymer
Body, methyl methacrylate-chloroprene copolymer,
Methyl acrylate-butadiene copolymer, methyl acrylate
-Isoprene copolymer, methyl acrylate-chloroprene
Copolymer, acrylonitrile-butadiene-styrene
Copolymer, acrylonitrile-chloroprene-styrene
And copolymers. Forming a phase mainly composed of a hydrophobic polymer
Examples of the polymer containing no conjugated diene hydrocarbon
Are elastomers containing a specific amount of chlorine and non-conjugated die
Hydrocarbons, and specifically,
Ruhydrin polymer, epichlorohydrin-ethylene oxide
Sid copolymer, epichlorohydrin-propyleneoxy
Copolymer and / or acrylic glycidyl ester
Epichlorohydrin rubber, a copolymer of polyester
Epichromer manufactured by Soda Industry Co., Ltd., HYDR manufactured by Goodvich Co., Ltd.
IN, Nippon Zeon Corporation GECHRON, Zeospan, Hevcules
HERCLOR], chlorinated polyethylene [Showa Denko
Eraslen Co., Ltd., Daisora Co., Ltd., Osaka Soda Industry Co., Ltd.
HORTALITZ manufactured by Hoechst Co., Ltd., Dow Chemical Co., Ltd.
Manufactured by Dow CPE. These hydrophobic polymers are
They may be used alone or in combination of two or more.
Therefore, it is preferable that the content be 20% by weight or more and 80% by weight or less.
New When the content is less than 20% by weight, the handling property is remarkably increased.
If it is 80% by weight or more, water developability is impaired.
You. A particularly preferred content is 30% by weight or more and 70% by weight or less.
Below. Forming a phase mainly composed of a hydrophilic polymer
Specific examples of the hydrophilic polymer include polyvinyl alcohol.
Coal, carboxymethylcellulose, hydroxyethyl
Lucerol, water-soluble polyurethane, water-soluble polyurea
Urethane, water-soluble polyester, water-soluble epoxy compound
Product, carboxyl group-containing acrylonitrile-butadiene
Copolymer, carboxyl group-containing styrene-butadiene
Copolymer, carboxyl group-containing polybutadiene, poly
Acrylamide, sodium polyacrylate, carbox
Sil group polyurea urethane, polyamic acid, etc. can be used
However, the present invention is not limited to these. The composition
In the case of a product, the phases are separated during compounding and mixing.
Are preferred to form a continuous phase and a dispersed phase.
The content of the water-based polymer is
From the viewpoint, 1 to 40% by weight, preferably 2% by weight
% To 30% by weight, particularly preferably 3% to 2% by weight.
0% by weight or less. As described above, the particulate hydrophilic or water-swellable elas
The tomer has been described by type, but in all compositions
Water-swellable elastomer content of 20
% Or more and preferably 80% by weight or less, more preferably
More preferably, it is 30% by weight or more and 70% by weight or less. 20 double
If the amount is less than%, problems occur in developability, shape retention characteristics, etc.
If the content exceeds 0% by weight, a problem occurs in water resistance, so that it is preferable.
Absent. In the present invention, the crosslinking density on the printing plate surface is increased.
To add a certain amount of the specified ethylenically unsaturated compound.
Preferably. In the present invention, the specific ethylenic
Saturated compounds are those having a molecular weight of 500 or less and at least two
Compounds having the above ethylenically unsaturated group at the terminal or side chain
Things. With certain such ethylenically unsaturated compounds
And ethylene glycol di (meth) acrylate,
Diethylene glycol di (meth) acrylate, 1,4
-Butanediol di (meth) acrylate, 1,6-he
Xandiol di (meth) acrylate, trimethylo
Lupropane tri (meth) acrylate, glycerin di
(Meth) acrylate, triethylene glycol di
TA) acrylate, PEG # 200 di (meth) acrylate,
PEG # 400 di (meth) acrylate, 1,3-butanegio
Dimethacrylate, neopentyl glycol di (meth
T) acrylate, 1,10-decanediol dimethac
Addition of ethylene oxide to bisphenol A
Di (meth) acrylate, ethylene oxide modified
Limethylolpropane triacrylate, pentaerythris
Litol triacrylate, pentaerythritol tet
Laacrylate, dipentaerythritol hexaacryl
Rate, 1,9-nonanediol di (meth) acrelay
G, light ester P-2M [manufactured by Kyoeisha Chemical Co., Ltd.],
Addition of 3 mol ethylene oxide to pentaerythritol
Triacrylate, oligopropylene glycol di
(Meth) acrylate, polytetramethylene glycol
Di (meth) acrylate and the like, especially alkylene
Glycol and alkylene ether crosslinking agents are preferred.
New Such a specific ethylenically unsaturated compound
Has a small molecular weight, and the
Distributed in sea components with low viscosity and relatively high fluidity.
Cheap. As a result, on a printing plate surface with a large amount of sea components,
Means that certain ethylenically unsaturated compounds are higher than in the plate
The crosslink density is greater than inside the plate. As a result, the present invention
Of the printing plate surface and inside
A difference occurs. Also, at the same time, specific ethylenically unsaturated compounds
The photosensitive layer that composes the printing plate because the content of is high on the printing plate surface
The overall sensitivity is dramatically increased, which is a feature of the present invention.
Advanced image reproduction not possible with conventional flexographic printing plates
Reality can be achieved. Specific ethylenically unsaturated compounds as described above
In order for an object to be distributed on the plate surface, its content must be
0.5% by weight to 10% by weight in the optical layer, especially
It is preferably in the range of 1 to 9% by weight. Contained from this range
As the amount increases, the dynamic hardness of the solid surface increases.
Printing pressure for good solid printing
Must be applied, in which case the halftone dots will collapse
I cannot get a print. In addition, the content is
When the number decreases, the cross-linking density of the printing plate surface decreases,
Surface is deformed during printing
No. In the present invention, the specific ethylenically unsaturated
The compound has a molecular weight of 1000 or more and has a terminal or
Is used in combination with a compound having an ethylenically unsaturated group in the side chain.
Is also good. Such a device is disclosed in, for example, Japanese Patent Application Laid-Open No. 1-2198.
Oligobutadiene as described in No. 33 Publication
(Meth) acrylate, oligostyrene butadiene (meth
T) Acrylate, oligonitrile butadiene (meth)
Acrylate, oligoisoprene (meth) acrylate
G, oligobutadiene urethane (meth) acrylate,
Oligostyrene butadiene (meth) acrylate,
Gobutadienamide (meth) acrylate and the like
However, the present invention is not limited to these. Such a minute
Having an ethylenically unsaturated group having a molecular weight of 1000 or more
The compound may be used in any ratio between the specific ethylenically unsaturated compound and
You may mix and use it at a rate. As the initiator used in the present invention, for example,
Nzophenones, acetophenones, α-diketones,
Acyloins, acyloin ethers, benzylalkyl
Luketals, polynuclear quinones, thioxanthones, reeds
And benzophene.
Non, chlorobenzophenone, acetophenone, benzi
, Diacetyl, benzoin, bivaloin, benzoin
Methyl ether, benzoin ethyl ether, benzyl
Diethyl ketal, benzyl diisopropyl ketal,
Anthraquinone, 1,4-naphthoquinone, 2-chloroa
Untraquinone, thioxanthone, 2-chlorothioxane
And acylphosphine oxide.
These may be used alone or in combination.
It is preferred to be incorporated in a 10% by weight composition. 0.
If it is less than 01% by weight, it may function as an initiator.
If it exceeds 10% by weight, it works like an internal filter
, The internal curing becomes insufficient. More preferred
Or 0.5 to 5% by weight. Water-developable photosensitive flexographic mark in the present invention
Use the usual method to make a printing plate
For example, the photosensitive resin composition may be coated with an adhesive layer.
Coated polyethylene terephthalate film
And a coat of a slip coat layer mainly composed of a water-soluble resin
Between the coated polyethylene terephthalate film
It can be made by scissors, heating and crimping.
Wear. Water-developable photosensitive flexographic mark in the present invention
The outline of the example of the method of manufacturing a printing plate has been described above.
The process will be described in more detail. Apply appropriate inspection negative
After irradiating with ultraviolet light under the exposure condition, the non-image
When the portion is removed, the photosensitive resin printing plate of the present invention is obtained.
The developer has a pH of 5.0 containing general water for daily use.
9.0 is optimal, and other alkaline compounds,
Surfactants, water-soluble organic solvents, and in some cases, organic acids
May be contained. In addition, as the above-mentioned surfactant,
Sodium alkyl naphthalene sulfonate, alkyl benze
Sodium sulfonate, Sodium alkylbenzene sulfonate
Is the most suitable, and in addition, anionic surfactants,
An on-type surfactant and an amphoteric surfactant can be used.
Furthermore, the temperature of the developer should be 25 to 50 ° C.
Is preferred. The photosensitive flexographic printing plate of the present invention is characterized in that
Normal drying to remove water adhering to the post-printing plate surface
To perform post-exposure in the same way as a normal printing plate.
Is obtained. In this case, as shown in FIG.
Halftone dots having a density of 50% or less and a density of 10
For 0% solid image, post-exposure, direct exposure to light
Continuous phase in which certain ethylenically unsaturated compounds are localized
Or the area is different. In other words, the printing unit area on the plate surface
Area of continuous phase to be cured by post-exposure to reinforce
Is larger in the halftone dot image than in the solid portion image.
Therefore, the dynamic hardness of the halftone printing plate surface of the present invention is
It becomes larger than the dynamic hardness of the solid portion surface. this
As a result, clear printing, which is a feature of the present invention, can be performed.
It seems that a flexible flexographic printing plate can be obtained. On the other hand, halftone dots having a density of 50% or less are
Is discontinuous and independent of the adjacent protrusion
You. For this reason, there are exposed portions and non-exposed portions,
Because the probability that a stop reaction is generated is small,
Has a high photocuring degree. On the other hand, in the solid part of 100% density,
There is no boundary between the light part and the non-exposed part, and the convex part exists continuously.
For this reason, the solid portion is generated by a termination reaction of the photoradical reaction.
The photocuring degree is small because the probability of
It becomes. The photosensitive resin composition of the present invention has
Certain ethylenically unsaturated compounds are localized in the continuous phase
Due to the large difference in photocuring degree between the halftone dot portion and the solid portion, each surface
The difference in dynamic hardness at
It seems to do. [0028] DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to embodiments.
However, the present invention is not limited to these examples. Note that
`` Parts '' means parts by weight.
It was evaluated by the method. 1) Measurement conditions for dynamic hardness Model: Dynamic ultra-fine hardness tester manufactured by Shimadzu Corporation Test mode: Soft material test (mode 3) Load: 2.5gf 2) Dynamic hardness measurement sample and measurement ・ For a photosensitive flexographic original plate with a plate thickness of 1.70 mm,
Halftone 200 lines as image-1% to 95%, minimum independent point
Diameter 100μm, minimum independent line width 30μm, minimum extraction
Width 100μm, minimum convex character 1 point, minimum extracted character 1 point
Inspection negatives, including ints, solid images, and step guides
Used during back exposure to make a plate making depth of about 0.8mm
, The depth of white spot with 300 μm slit width is at least 3
0% or more and 1% of 200 dots are reproduced
Table exposure time with minimum exposure, proper development process and drying process
Through the post-exposure curing process to obtain a flexographic printing plate
Was. The obtained printing plate has a halftone dot of 150 lines and 5% and a density of 10%.
Dynamic hardness of the outermost surface of each printing plate with 0% solid part
Measure. Embodiment 1 29.0 parts of polytetramethylene glycol (Hodogaya Chemical
G-850 manufactured by KK) dimethylolpropionic acid (Fujii
62.0 parts, hexamethylene diisocyanate
119.0 parts (manufactured by Nippon Polyurethane Industry Co., Ltd.), and
5.0 parts of n-butyltin dilaurate in tetrahydro
A solution of 300.0 parts of furan was dissolved in 1
Place the flask in a 6-liter flask while stirring.
The mixture was heated to 5 ° C., and the reaction was continued for 3 hours. More hydroxye
Add 26.0 parts of chill methacrylate and heat to 65 ° C.
The reaction was continued for 2 hours. In a separate container
Acrylonitrile with butadiene oligomer (Hycar AT
(BNX 1300 x 16 Ube Industries) 184.0 parts of tetrahydrof
The solution prepared by dissolving in 270.0 parts of run
The mixture was added to the flask under stirring at room temperature. Profit
The polymer solution was dried under reduced pressure to obtain tetrahydrofuran.
Was removed to obtain a hydrophilic polymer [I]. 10.5 parts of the above hydrophilic polymer, nitrile
Butadiene rubber (acrylonitrile 35%) (NIPUL-10
42 Nippon Bion Co., Ltd. 33 parts, butadiene rubber (JSR BR)
OLLL) 22 parts, oligobutadiene acrylate (PB-
A Kyoeisha Chemical Co., Ltd. 29 parts, 1.6-hexanediol
3 parts of dimethacrylate, dimethylbenzene as photoinitiator
Zirketal 2 parts, hydroquinone monomethyl ether
0.1 part is heated with 40 parts of toluene and 10 parts of water.
Kneading at 105 ° C using a mixer, then toluene and water
Was distilled off under reduced pressure. The obtained photosensitive resin composition was coated to a thickness of 12
Polyethylene on 5μm polyethylene terephthalate film
Same as film coated with ester-based adhesive layer
Anti-adhesion layer on polyethylene terephthalate film
(Polyvinyl alcohol, propylene glycol, interface
(Containing an activator)
So that the adhesion layer and the anti-adhesion layer come into contact with the photosensitive resin composition.
2), 105 ° C, 100 kg / cm with a heat press^Two
1.7mm thick by heating and pressing for 1 minute
Was prepared. The obtained original cover cover
Peel off the film, halftone 200 line -1% to 95%, minimum
Independent point diameter 100μm, minimum convex character, 1 point, minimum
Inspection including 1-point solid image and step guide
Illuminating the negative, the illuminance at 365 mm light is approximately 17.
5w / m^Two(Lamp FR20 manufactured by Anderson A Vreeland)
T12-BL-9-BP) to perform back exposure and front exposure
To remove the negative film and remove the alkyl naphthalene
In neutral water at 40 ° C containing 4% by weight of sodium sulfonate
Developed for 12 minutes and dried for 60 minutes for 20 minutes. More table
Exposure was performed to obtain a printing plate. The printing plate obtained has a relief depth of 0.8
mm, halftone 200 lines 1% to 95%, minimum independent point
Diameter 100μm, minimum independent line width 30μm, minimum wire width 1
00 μm, minimum convex character 1 point, minimum extracted character 1 point
Images that cannot be realized with conventional flexographic printing plates
Reproducibility was obtained. Also, the dots and solids of the obtained printing plate
Table 1 shows the dynamic hardness of each part and its ratio. Table 1
More clearly, the resulting printing plate was used
Printing that faithfully reproduces the original negative image when printing with g
It turns out that things are obtained. Embodiment 2 In Example 1, 1.6 hexanediol dimethacrylate
Dipentaerythritol hexaa instead of 3 parts of rate
Except for using 3 parts of acrylate, all were the same as in Example 1.
As a result, the same results as in Example 1 were obtained. Embodiment 3 In Example 1, the glue of 33 parts of nitrile butadiene rubber was used.
Cis isoprene rubber (IR-10 Kuraray Co., Ltd.)
Except that 33 parts were used, all were carried out in the same manner as in Example 1.
However, the same results as in Example 1 were obtained. Embodiment 4 Isoprene rubber (IR-310 Shell Japan Co., Ltd.)
21 parts, polybutadiene rubber (JSR BROLL Japan
Synthetic Rubber Co., Ltd. 10.5 parts, nitrile butadiene rubber
(JSR230S Nippon Synthetic Rubber Co., Ltd.) 4.5 parts, liquid
Isoprene rubber (LIR-410 Kuraray Co., Ltd.) 5.0
Part, polybutadiene acrylate (PBA-Kyoeisha Chemical
30 parts, hydrophilic polymer [I] 10.5 parts, 1,
6 hexanediol dimethacrylate 5 parts, benzyldi
2.0 parts of methyl ketal hydroquinone monomethyl acrylate
Was mixed in the same manner as in Example 1 and evaluated.
As a result, the same results as in Example 1 were obtained. Embodiment 5 Chlorinated polyethylene (Daisolak H-135 Daiso)
Co., Ltd.) 45 parts, butadiene rubber (JSR BROLL)
Nippon Synthetic Rubber Co., Ltd., 14 parts, butadiene oligoacrylate
Rate (PB-A Kyoeisha Chemical Co., Ltd. 25 parts, 1,6 hex
2.5 parts of sundiol dimethacrylate, dipentaerythris
Litol hexaacrylate 2.5 parts), hydrophilic polymer
10.5 parts of I, 2 parts of benzyldimethyl ketal, high
0.3 parts of droquinone monomethyl ether as in Example 1
The mixture was mixed and evaluated as described above.
Similar results were obtained. Embodiment 6 Phosphate ester group-containing random copolymer (monomer composition
Butadiene 65% Methyl acrylate 4%, Ethyl phosphate
20% len methacrylate, 10% styrene, divinyl
Benzene 1%) 40 parts, polystyrene-polybutadiene
-27 parts of a polystyrene type block copolymer, liquid polybu
Tadiene (Nisso-PBB1000) 25 parts, benzyl
Dimethyl ketal 1 part, 1,6 hexanediol dimeta
Melt and knead 7 parts of acrylate using a heating kneader,
A light-sensitive resin composition was obtained. The obtained photosensitive resin composition was
Evaluation was performed in the same manner as in Example 1.
Similar results were obtained. Embodiment 7 In Example 6, a random copolymer containing a phosphate ester group was used.
Carboxyl group-containing core shell instead of 40 parts of body
Logel (core: 2-ethylhexyl acrylate-89
Part, allyl acrylate + 1 part, 1,4 butanediol
8 parts of a copolymer, shell: n-butyl acrylate 80
Part, methacrylic acid 20 part copolymer, reaction between core and shell
Ratio was 2/1) as in Example 6, except that 40 parts were used.
As a result, the same results as in Example 6 were obtained. Comparative Example 1 1,6-hexanediol dimethacrylate in Example 1
The evaluation was performed in the same manner as in Example 1 except for the
50 lines 3% to 95% Minimum independent point diameter 200μm, minimum
Independent line width 5μm, minimum line width 150μm, minimum convex character 3
Point, minimum image reproducibility of 4 points only
Was not. In addition, the dynamics of printing halftone dots and solid areas
The hardness and the ratio are shown in Table 1. [0039] [Table 1] [0040] As is apparent from the above description, the present invention
Water-developable photosensitive flexographic printing plates use conventional flexographic printing.
Achieves high image reproducibility that could not be achieved
It is great to contribute.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-9-80743 (JP, A) JP-A-10-123710 (JP, A) JP-A-9-106068 (JP, A) JP-A-10-108 282661 (JP, a) JP flat 5-249668 (JP, a) JitsuHiraku Akira 62-57264 (JP, U) (58 ) investigated the field (Int.Cl. ^7, DB name) G03F 7/00 - 7 / 42

Claims (1)

(57) [Claims] [Claim 1] In a water-developable photosensitive flexographic printing plate,
Water wherein the ratio (A) / (B) of the dynamic hardness (A) of the halftone dot surface having a concentration of 50% or less to the dynamic hardness (B) of the solid portion surface having a concentration of 100% is 1.1 or more. Developable photosensitive flexographic printing plate.