JPH033211B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing multiple printing plates.

It is well known in the printing field that printing plates made from two or more layers of different hardness (e.g., a softer underlayer material combined with a harder material commonly used as a printing surface) result in improved print quality. It is generally well recognized by those skilled in the art. This is evidenced by the widespread use of foam backings for printing plates.

Printing plates formed from photopolymerized materials are also well known in the printing art. For example, US Patent No. 2760863
(Plambeck). In an attempt to combine the advantages of photopolymerization plate making with the advantages of soft-backed printing plates, US Patent No.
(Crawford); same No. 3157505 (Notley) and same No. 3157505 (Notley);
This led to the development of printing plates made from multiple layers of solid photopolymer as described in No. 3,990,897 (Zuerger et al.). Although such solid multilayer printing plates have advantages, they also have some disadvantages. Because adhesives are often required to bond multiple solid photopolymer layers together, and because the soft base layer is not an integral part of the relief surface, delamination of the base layer from the relief polymer can occur. be. Solid printing plates also present warehousing problems due to the varying plate dimensions and layer thicknesses required by the printing industry. Additionally, printing plates made from precast solid polymers are more difficult to develop and wash out than photopolymer plates made from liquid resins.
Solid printing plates are also subject to storage degradation due to component migration and distortion caused by handling.

According to the present invention, a method for making a printing plate having at least two different types of adjacent layers is provided. This method uses (A) a polymer having a normal boiling point higher than about 100°C, a molecular weight less than about 1500, and having one or more ethylenically unsaturated groups capable of forming a high polymer by photoinitiated polymerization; at least one addition polymerizable compound; at least one unsaturated polymeric type substance soluble in the addition polymerizable compound; at least one polymerization inhibitor; and a photointiator. (B) a printing layer consisting of a photopolymerizable liquid composition having a normal boiling point higher than about 100°C, a molecular weight less than about 1500, and capable of forming a high polymer by photoinitiated polymerization; at least one addition-polymerizable compound having one or more saturated groups; at least one unsaturated polymer-type substance soluble in the addition-polymerizable compound; at least one polymerization inhibitor; and A photopolymerizable element comprising a base layer consisting of a different type of photopolymerizable liquid composition containing a photopolymerization initiator, at least one of a photopolymerization initiator, a polymerization inhibitor, and an ultraviolet absorber. By adjusting the concentration, the base layer contains more photoinitiator than the printed layer so that the photopolymerization rate of the base layer is about 1.5 to 250 times that of the printed layer, and (i ) adjusting the degree of unsaturation of the unsaturated polymeric substance; (ii) adding a crosslinking agent in a suitable manner; and (iii) adjusting the amount of the addition polymerizable compound. Both compositions comprising the base layer are activated through a photographic master to photopolymerizable elements having different crosslinking properties characterized by a difference in modulus of both layers of at least about 50 psi (3.5 Kg/cm ² ) after exposure to light. It consists of exposing to actinic light and removing the unpolymerized parts of both layers.

As can be understood from the above explanation, the modulus of each layer is controlled by the crosslinking properties of the two different photopolymerizable liquid compositions, and the difference in photopolymerization rate increases the shoulder angle of the photopolymerizable layer. control.

Each layer thickness is approximately 1-250 mils (0.0254-6.35mm)
It is generally preferred that the layer used as the printing layer has a thickness within the range of about 4 to 150 mils (0.102 to 3.81 mm). In order to conveniently remove the unpolymerized portions of both layers, the photopolymerizable composition can be dispersed at a concentration of about 1 to 40% by weight in a solvent that has no solubilizing effect on the polymerized resin. It is preferable to have one. Suitable solvents are water, aqueous solutions of bases or water-miscible organic solvents.

The present invention also relates to a printing plate made by the above method, in which the printing layer is doctored on a supported photographic master protected by a cover film, and the base layer is covered with a support layer. We also provide printed versions as shown below.

The photopolymerizable compositions used in the present invention are such that both adjacent layers still retain separate entities after the curing process, yet the layers do not separate or split during the printing process without the aid of an adhesive. It is of such a nature that it bonds sufficiently tightly. The unsaturated polymeric component (hereinafter referred to as prepolymer) is selected from such types as polyesters, polyurethanes, polyethers, polybutadienes and polyamides, the only limitation being that this polymer is soluble in the addition polymerizable compound. That's what it means. Dyes and inert UV absorbers are often desirable additives to the composition, and waxes and other additives may be added to the resin if desired.

Suitable unsaturated polymeric components that can be used as prepolymers in photopolymerizable compositions include at least one polyol and at least one unsaturated dicarboxylic acid, such as those described in U.S. Pat. No. 3,858,510 (Kai et al.). Unsaturated polyesters made from anhydrides or their methyl or ethyl esters; unsaturated polyester-polyether block polyurethanes as described in U.S. Pat. No. 3,960,572 (Ibata et al.); unsaturated as described in West German Pat. No. 2,611,89 Polyether polyurethane; US Patent No.
Polyenes such as those described in 3661575 (Ketley et al.)
polyol composition; and Belgian patent no.
Butadiene, isoprene, chloroprene, styrene, isobutylene, acrylonitrile and ethylene, in which the unsaturated group is attached to the polymer through a combination of at least two ether, thioether, ester, keto or amide groups as described in There are terminally unsaturated homopolymers and copolymers.

Generally, this unsaturated polymeric component may be present in an amount of about 40-95% by weight. The addition polymerizable compound may also be present in an amount of about 2 to 50% by weight.

Typical addition polymerizable compounds having ethylenically unsaturated bonds include acrylic acid, methacrylic acid, methacrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-propyl acrylate, and n-propyl acrylate.
-hexyl acrylate, n-octyl acrylate, cyclohexyl acrylate, allyl acrylate, glycidyl acrylate, styrene, vinyltoluene, divinylbenzene, carboxystyrene, diallyl phthalate, triallyl cyanurate, vinyl acetate, acrylamide, methacrylamide, n-butylacrylamide , N
-Methylol acrylamide, N-methylolmethacrylamide, N-methoxymethylacrylamide, N-ethoxymethylacrylamide, N-
Ethoxymethylmethacrylamide, N-n-butoxymethylacrylamide, N,N'-methylenebisacrylamide, N,N'-methylenebismethacrylamide, N,N'-trimethylenebisacrylamide, N,N'-hexamethylenebis Acrylamide, methyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, lauryl methacrylate, 2
-Hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 3-chloro-2-
Hydroxypropyl acrylate, 4-hydroxybutyl acrylate, diethylene glycol monoacrylate, dipropylene glycol monoacrylate, polyethylene glycol monoacrylate, ethylene glycol diacrylate, tetraethylene glycol diacrylate, propylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate , tetraethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane triacrylate, 1,6-hexanediol dimethacrylate, N-3-oxopropylacrylamide, N-3-oxobutylacrylamide, N-
3-oxo-1-methylbutylacrylamide,
N-3-oxo-1-dibutyl-2-n-propylheptyl acrylamide and the like.

The composition of each layer must be adjusted so that each layer has the desired relative hardness after curing. This can be achieved by adjusting the amount of crosslinking (degree of crosslinking) that occurs during photopolymerization. That is, the higher the degree of crosslinking of the polymerization product, the harder it becomes. There are several ways to adjust the degree of crosslinking. One example is adjusting the degree of unsaturation in the prepolymer during its manufacturing process to provide the required number of crosslinking sites. Also,
The degree of crosslinking can also be controlled by appropriate selection of addition polymerizable compounds with varying degrees of unsaturation, i.e. compounds acting as crosslinking agents, or by adjusting the amount of addition polymerizable compounds in the photopolymerizable composition. can.

Generally, each layer of the printing plate of the present invention should have a modulus in the range of about 50 to 80,000 psi (3.5 to 5,600 Kg/ ^cm2 ). Also, the modulus of the polymer in the top layer (i.e., printing layer) after curing should be: at least 50 pai (3.5 Kg/cm ² ) higher than the modulus of the polymer of the underlying layer (i.e. base layer) after curing (if a hard printing layer/soft substrate combination is desired);
Alternatively, it may be low (if a soft printing layer/hard substrate combination is desired).

In the description of the present invention, modulus is used to describe differences in hardness. The Young's modulus of the present invention is determined by extending the initial linear portion of the stress-strain curve obtained in accordance with ASTM D-638 and dividing the slope of the load with respect to this elongation by the cross-sectional area of the sample. Sample preparation was performed using a GE F-20-T-12BL fluorescent lamp using a 40 mil (1.0 mm) thick plate.
Back exposure for 20 seconds at an intensity of 1.2 mW/cm ² and 270 sec at an intensity of 8 mW/cm ² using a medium pressure mercury arc lamp (2KW).
This is done after being cured by second relief exposure.

For some printing applications, such as printing on rough substrates such as cardboard boxes, jute sacks, paper bags, etc.
It is desirable to use printing plates with a soft top layer (printing layer) and a harder bottom layer. Softer top layer polymers generally carry more ink and therefore transfer more ink to the substrate than printing plates with harder surfaces. Printing plates with a soft printing surface generally have less wiping effect during printing than printing plates with a hard surface.

The polymerization rate of the liquid photosensitive resin used in the present invention is
Amount and type of polymerization initiator, amount and type of polymerization inhibitor,
It is well accepted from photopolymerization theory that it depends on the amount and type of UV absorber and the overall thickness of the resin layer (G. Odian, "Principles of Polymerization", McGraw-Hill Publishers, p. 183, New York, USA).

The rate of photopolymerization also depends on the reactivity and absorption spectrum of the resin and the corresponding spectral energy distribution and light intensity of the light source used for exposure. The reduction in shoulder formation in the upper layer (giving a larger shoulder angle) is a result of the lower absorption of divergent or stray light in adjacent parts of the image area and the use of resins that react slowly with such divergent light. This is facilitated by Such delay of the light absorbing agent is achieved by lowering the concentration of the photopolymerization initiator and other light absorbing agents in the upper resin layer. For the same reason, when the concentration of photopolymerization initiator and other light absorbers in the lower resin layer is high,
The use of divergent light that has passed through the overlying resin (unabsorbed) or reflected from the support sheet will result in the formation of insoluble polymer over an area larger than the image gap (resulting in
shoulder angle becomes smaller). Therefore, in the present invention, it is important that the upper layer resin has a lower photosensitivity (photospeed, ie, polymerization rate) than that of the lower layer resin.

Acceptable polymerization initiators include benzoin, α-
Hydroxymethylbenzoin, 2,2-diethoxyacetophenone, haloakylbenzophenone,
α,α,α.Trichloroacetophenone, ketosulfides, 2-alkoxy-1,3.diphenyl-
1,3-propanedione, alkylbenzoin ether, α,α-dimethoxyphenylacetophenone, 1-phenyl-1,2-propanedione
Examples include 2,0-benzyloxime and S,S'-diphenylthiocarbonate. Alkylbenzoin ethers and α,α-dimethoxyphenylacetophenone are preferred polymerization initiators. Examples of ultraviolet absorbers or dyes include acetophenone, benzophenone, thioxanthone, anthraquinone, fluorenone, benzotriazole, and O-nitroaniline. Preferred UV absorbers or dyes are benzophenone and O-nitroaniline.

Thus, in parallel with the above compositional adjustments used to provide the desired modulus, the concentrations of polymerization initiators, polymerization inhibitors, and/or UV absorbers may also be adjusted depending on the upper resin layer (whether it is harder or softer than the lower layer). (regardless of) should be adjusted so that the photosensitivity is relatively lower than the resin used as the underlying layer. The sensitivity of the resin used as the lower layer to ultraviolet rays is approximately 1.5 to 250 times higher than that of the resin used as the upper layer.
The size can be increased by a factor of about 5 to 20 times, preferably about 5 to 20 times.
A preferred method for adjusting the photosensitivity is to adjust the concentration of the polymerization initiator in the resin used for both layers in advance. Alkylbenzoin ether or α,α
- For initiators such as dimethoxyphenylacetophenone, the amount used in the upper layer (printing layer) is approx.
0.1-1% by weight, approximately 0.5-2.5% by weight in the lower layer
That's fine. The preferred amount of initiator used in the upper layer is approximately
0.3-0.5% by weight, and about 0.8-1.5% by weight in the lower layer.

The accompanying drawings illustrate the effect of the above-mentioned differences in photosensitivity. This drawing shows a cross-sectional view of a part of a printing plate made according to the present invention. By changing the balance of photosensitivity between both the resins used as the upper layer 3 and the lower layer 2, the shoulder angle b (i.e., the difference between the slanted outer edge of the upper layer 3 and the interface between the upper layer and the lower layer) the shoulder angle a of the lower layer (i.e. the angle formed by the lip of the slanted outer edge of the lower layer 2 and the interface between the lower layer/support sheet, provided that this interface is It is possible to produce printing plates that are at least 10° larger than (parallel to the interface between the underlying layers).

Shoulder angle b of the upper layer is approximately 10~10~
It can be increased by 85°, preferably about 30-60°. This is particularly advantageous in printing plates with a hard top layer (as this structure provides a balance between print quality and plate durability not hitherto achieved in single-layer printing plates). Furthermore, since the space in the relief surface becomes wider due to the increased shoulder angle, blockage by ink, lint, etc. during printing operations is prevented, and therefore printing stoppage time for cleaning can be reduced. The multilayer resin layers, the composition of which has been adjusted as described above, are synchronously and harmonically formed by exposure to ultraviolet light to form a printing plate with integrated multilayer relief elements that are precisely tailored. There is little or no damage due to delamination at the interface between both layers.

The photopolymerizable composition may contain at least one polymerization inhibitor. Generally, the amount of polymerization inhibitor is about 300~
It is good within the range of 3000ppm, but especially about 1000~
2000ppm is preferred. Examples of useful polymerization inhibitors are di-t-butyl p-cresol, hydroquinone monomethyl ether, pyrogallol, quinone, phenothiazine, and the like. Particularly preferred is di-t-butyl p-cresol. In order to prevent excessive mixing of the photopolymerizable compositions of both layers during the plate-making operation, while still allowing proper flow thereof, the viscosity of the compositions of both layers should be between about 1000 and 60000 cp; Particularly preferred is about 5,000 to 30,000 cp. However, the viscosities of the compositions used for both do not need to be the same as long as they fall within the above ranges. In the Examples described below, the photopolymerizable compositions all have a viscosity within the above range.

Printing plates with a hard top layer and a soft base layer offer superior print quality and greater screen latitude.
latitude). In single-layer printing plates, as the number of prints increases, the printed surface becomes distorted, and the ink film on the print is usually larger than the intended image area of the printing plate. However, in the combination of a hard top layer and a soft base layer, the distortion due to printing is absorbed by the softer base layer (because the base layer is formulated and designed to compress before the harder top layer polymer). In this way, the softer base layer polymer compresses first so that the harder top layer polymer does not distort and the fidelity of the printed image is maintained over a wide range of print runs. Also, because of the finely finished structure of the relief surface in the harder top layer (due to the lower concentration of polymerization initiator), the relief image does not begin to spread until the softer base layer is highly compressed. In conventional printing plates prepared from a single liquid resin, the image begins to spread from the relief surface. Furthermore, in this multilayer printing plate, image expansion due to plate wear does not occur until the entire surface of the upper layer is worn away. The height (depth) of this upper layer can be easily adjusted in the liquid system used in the present invention, so
Image expansion due to plate wear can be avoided.

In order to easily form the multilayer photopolymerizable printing plate of the present invention at the appropriate location on the printing plate, a liquid photopolymerizable material, which will eventually become the upper layer (printing layer), is placed on top of the polymer film that protects the negative. Apply a polymeric resin to the desired thickness (doctoring). While this first resin is still in a liquid state, a second liquid resin, which will eventually become the base layer, is doctored onto it to a suitable thickness, and the whole is placed on a suitable support (with an adhesive if desired). Cover with It is generally desirable to use a film that is transparent to ultraviolet light as the support (it is possible to create a wider shoulder angle in the base layer than with an opaque support in the secondary back exposure, and this wider shoulder angle as it provides a stronger support for the relief surface).
Both resin layers remain in liquid form during the aforementioned operations. Then, by shining ultraviolet light through the negative, only specific parts of the plate are exposed. Thereafter, the unpolymerized resin is removed from the parts of the plate that were not completely exposed, ie, the parts corresponding to the dark areas of the negative.

The above description merely describes one example of the plate making method for the printing plate of the present invention, and does not limit the plate making method or the number of layers used.

In the examples below, all parts are by weight, and the photopolymerizable compositions described all have viscosities in the range of about 1000 to 60000 cp.

Example 1 A Mylar support sheet approximately 4 mils (0.1 mm) thick is coated with an adhesive solution containing a red dye as an antihalation agent.

Triethylene glycol dimethacrylate 45
parts, 15 parts of N-3-oxobutylacrylamide,
A polyester (prepared from 2 moles of diethylene glycol, 2 moles of propylene glycol, 2 moles of adipic acid and 2 moles of fumaric acid) was added to a mixture consisting of 0.038 parts of di-tert-butyl p-cresol, 0.02 parts of hydroquinone methyl ether and 0.5 parts of benzoin isobutyl ether. A liquid polyester resin composition prepared by dissolving 100 parts of
0.75 mil (0.019
Doctor onto a 4-6 mil (0.10-0.15 mm) thick polypropylene film. This polyester resin composition has a hardness after photo-curing.
50D, the modulus is 52503psi (3691Kg/cm ² ). Next, on top of the 4-6 mil thick polyester resin composition still in the liquid state, the polyester (from 1 mole diethylene glycol, 1 mole propylene glycol, 0.5 mole fumaric acid, 0.5 mole phthalic anhydride and 1 mole adipic acid) is applied. prepared by dissolving 100 parts of styrene, 50 parts of triethylene glycol dimethacrylate, 0.07 parts of di-tert-butyl p-cresol, 0.03 parts of hydroquinone methyl ether, and 1.8 parts of benzoin isobutyl ether. 7~ liquid polyester resin composition
Doctor to 9 mil (0.18-0.23 mm) thickness.
This polyester resin composition has a hardness of 67 A after photopolymerization and a modulus of 1260 psi (88.6 Kg/cm ² ). Place the above support sheet on top of these liquid resin layers, and insert the GE F20 from the support sheet side.
-T-12BL Fluorescent lamp [Ultraviolet backlight (back)
ray) The intensity is 1.2 milliwatts as measured by a meter.
cm ² ] for 10 seconds. The resin sandwich was then irradiated from the negative side with a 2000 watt medium pressure mercury-arc lamp (intensity 7 milliwatts/cm ² ) for 80 seconds. After exposure, peel off the polypropylene film and
% sodium hydroxide solution for 2 minutes, then with water.
Remove unexposed polymer with a 30 second spray wash. The dried plate is further exposed to a fluorescent lamp (intensity 1.2 mW/cm ² ) for 10 minutes under a nitrogen atmosphere.
The thickness of the generated plate (thickness including the support sheet)
was 17 mils (0.43 mm), the relief height was 12-13 mils (0.30-0.33 mm), and the etch depth in certain shadow areas was 0.0067 mm. In contrast, the depth of the etch in the similar shadow area of the plate using only the polyester resin composition was only 0.0025 mm. In addition, a clear relief image bonded to the substrate is generated corresponding to the transparent portion of the negative. The angle of the highlight element in the base layer is 58° with respect to the horizontal plane, and the angle of this same highlight element with the horizontal plane in the upper layer is 58° with respect to the horizontal plane.
It is 85°. The angle of the same highlight element in a plate made from only a polyester resin composition is 50°. This change in the angle of the highlight element for the multilayer plate occurs approximately 4 mils (0.1 mm) below the relief surface.

This plate exhibits a long print life and has a 10 mil (0.25
No enlargement of the image is observed when applying a pressure of mm) and with plate wear. There are no observable blockages or low spots, the overall screen and tonal range retained and printed with this plate is wider than the non-multilayer version, and the overall print quality and appearance is also better than the non-multilayer printing version. better than that observed in

Example 2 A multilayer plate was prepared as described in Example 1 except that the liquid polyester resin composition was doctored onto a polypropylene film at a thickness of 8 mils (0.20 mm) and then the liquid polyester resin composition was Doctor with mil (0.25mm) thickness. Exposure of the plate was 20 seconds from the support sheet side and 80 seconds from the negative side.
Do it for seconds. The resulting 22 mil (0.56 mm) thick plate was developed with the cleaning solution described in Example 1 and the relief height was 15 mil. The lower part of the relief element makes an angle of 38° to the horizontal plane, and the upper part makes an angle of 78°. The depth of the etch in the shadow part is 0.015mm. This version is Example 1
It has an overall printing quality similar to that of the original version.

Example 3 A multilayer plate is prepared as described in Example 1, except that a 4-6 mil (0.10-0.15 mm) thick liquid polyurethane resin composition is used as the top layer. The polyurethane prepolymer used for this resin was prepared using a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate.
26.1 g in the presence of dibutyltin dilaurate
This is carried out by reacting with 200 g of polyethylene adipate diol (molecular weight approximately 450) at 70°C for 2 hours with stirring under a nitrogen atmosphere. Next, the obtained isocyanate-terminated polyester urethane is further reacted with 100 g of polypropylene glycol diol (molecular weight about 1000) at 70° C. for 2 hours. 300 g of the resulting polyester-polyether urethane block polymer were then mixed with 2-hydroxypropyl methacrylate 25 containing 0.09 g of 2,6-di-t-butyl p-cresol as a stabilizer.
g and react at 70°C for 2 hours while blowing air. 70 parts of the obtained prepolymer were mixed with 12 parts of 2-hydroxypropyl methacrylate, 16 parts of n-butylacrylamide, 2 parts of acrylamide, 0.04 part of di-t-butyl p-cresol, 0.04 part of hydroquinone methyl ether, and α,α-dimethoxyf. Add to 0.3 part of enylacetophenone. The thus prepared polyurethane resin composition has a hardness of 70 A after photocuring and a modulus of 920 psi (64 Kg/cm ² ).
It is. Furthermore, on top of a 4-6 mil (0.10-0.15 mm) layer of this polyurethane resin composition which is in liquid form, a 7-9 mil (0.18-0.23 mm) layer of the liquid polyester resin composition of Example 1 is doctored. do. This is then given a 120 second back exposure and a 120 second relief exposure. A 17 mil (0.43 mm) thick plate with 13 mil (0.33 mm) relief was used in Example 1.
obtained after the development treatment described in . The angle of the relief highlight elements is 48° in the base layer and 82° in the upper layer.
The etching depth of the shadow part is 0.0083mm. This plate has the overall print quality advantages of the plate described in Example 1, but also has a polyurethane-based polymer composition that is more resistant to abrasion than when a polyester-based polymer composition is used for the relief surface. It also has the added benefit of being good.

Example 4 α,α-dimethoxyphenylacetophenone
A 5-8 mil (0.13-0.20 mm) thick layer of the liquid polyurethane resin composition described in Example 3 containing 0.5 parts instead of 0.3 parts was coated with Bychrome.
Doctor onto a polypropylene film that is placed over the test negative containing the screen tint. On top of this is a liquid polyurethane resin composition with a thickness of 50 to 53 mils (1.27 to
Apply a layer of 1.35mm) with a doctor. This polyurethane resin composition contains 37.65 parts of polyethylene adipate diol, 34.97 parts of polypropylene glycol diol, and 80 parts of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate.
70 parts of a polyurethane prepolymer prepared from 7.31 parts of a mixture of 20 and 17.75 parts of polyethylene glycol monomethacrylate (average degree of polymerization 7) as a capping agent, 12 parts of n-butylacrylamide, 2-hydroxyethyl methacrylate
12 parts of acrylamide, 2.0 parts of styrene, 0.05 parts of di-t-butyl p-cresol, and 1.0 parts of benzoisobutyl ether. The hardness of the polymer obtained by photo-curing this resin composition is 40A.
The modulus is 220psi (15Kg/cm ² ). The plate is formed by exposing the liquid resin layer to light for 55 seconds from the side of the support sheet prepared as described in Example 1 without containing an antihalation dye and for 180 seconds from the negative side.

Example 5 The support sheet described in Example 1, which does not contain red dye for preventing halation, was used, and the thickness was 50 to 53 mm.
mill (1.27-1.35 mm) liquid polyurethane resin composition (76.52 parts of the prepolymer used in the polyurethane resin composition of Example 4, 9.98 parts of lauryl methacrylate, 1.60 parts of 2-hydroxyethyl methacrylate, 10.64 parts of polyethylene glycol dimethacrylate, (prepared by adding 0.04 part di-t-butyl p-cresol, 0.04 part hydroquinone methyl ether, and 1 part benzoin isobutyl ether) to a thickness of 5 to
a layer of 8 mil (0.13-0.2 mm) of the liquid polyurethane resin composition described in Example 3 (but containing α,α-dimethoxyphenylacetophenone in an amount of 0.1 part instead of 0.3 part); Prepare a multilayer plate by doctoring. When photocured, the above polyurethane resin composition has a hardness of 22A and a modulus of 150 psi (10.5 Kg/cm ² ). Plate making starts from the support sheet side for 80 seconds.
Bychrome Screen Test Performed by 180 second exposure from the negative side. 62 mil (1.6 mm) thick with 30 mil (0.76 mm) relief, precision finished relief printing elements and open etch depth
The plate is developed and post-exposed as described in Example 1.

Example 6 70 parts of the prepolymer used in the preparation of the polyurethane resin composition described in Example 3 were mixed with 10 parts of triethylene glycol dimethacrylate, 16 parts of n-butylacrylamide, 4 parts of methyl methacrylate,
A liquid polyurethane resin composition prepared by adding 0.3 parts of hydroquinone methyl ether, 0.3 parts of di-t-butyl p-cresol, and 0.3 parts of α,α-dimethoxyphenylacetophenone (which after photocuring Produces a polymer with hardness of 90A and modulus of 10000psi = 703Kg/ ^cm2 )
A 125 mil (3.18 mm) thick layer of is doctored onto the polyester film covering the original line drawing negative. 70 parts of the prepolymer used to prepare the polyurethane resin composition described in Example 4 (but capped with polyethylene glycol monomethacrylate having an average degree of polymerization of 15 instead of 7) was replaced with 2-hydroxyethyl methacrylate. 12 parts, n-butylacrylamide 12
parts, acrylamide 2 parts, styrene 5 parts, hydroquinone methyl ether 0.05 parts, di-t-butyl p
- a liquid polyurethane resin composition prepared by adding 0.05 part of cresol and 0.3 part of α,α-dimethoxyphenylacetophenone, which after photocuring has a hardness of 35 A and a modulus of
171psi = 120Kg/ ^cm2 of polymer) thickness
A 125 mil (3.18 mm) layer is doctored onto the liquid polyurethane composition described above and the support sheet described in Example 1 without the antihalation red dye is applied. Curing of the plate starts from the support sheet side.
Exposure for 2.5 minutes and 7 minutes from the negative side.
A 250 mil (6.35 mm) plate with 125 mil (3.18 mm) relief was developed as described above and has a strong relief element with a fine finish.

Example 7 Carboxyl-terminated polybutadiene (Hycar
CTB-2000×162, Gutsudoritsusha) 100 copies,
6.7 parts of glycidyl methacrylate, 0.015 parts of phenothiazine, (0.0075 parts of nitrobenzene, 0.08 parts of sodium methoxide) and di-t-butyl p-
Add 0.20 parts of cresol. The mixture is heated to 100° C. in the presence of a stream of air until an acid number of 0.36 is obtained. 88 parts of this prepolymer are added to 6 parts of 1,6-hexanediol dimethacrylate, 6 parts of lauryl methacrylate, and 0.6 parts of α,α-diethoxyacetophenone. The resulting composition yields a photocurable polymer with a hardness of 55 A and a modulus of 600 psi (42 Kg/cm ² ). A 5 to 15 mil (0.13 to 0.38 mm) layer of this liquid polybutadiene resin composition is doctored onto the polypropylene film covering the original line drawing negative, and a liquid polyurethane resin composition ( After curing, the hardness is 40A and the modulus is
80~90mil (2.0~2.3mm) with 220psi=15.5Kg/ ^cm2 )
Doctor the layer. The plate was cured in the direction of the support in Example 1 (without antihalation dye).
This is done by exposing for 2 minutes from the side and 5 minutes from the negative side. Development of the plate is carried out by spray cleaning with a 1.0% warm aqueous solution (50° C.) of Bioterge α-olefin sulfonate detergent (Stepon Chem. Co.). Thereafter, a post-exposure process is performed for 10 minutes in a nitrogen atmosphere. The resulting 90-95 mil (2.29-2.41 mm) thick plate with 45 mil (1.14 mm) relief, in addition to the overall printing properties of the plate in the previous example, is resistant to alcohol-based inks and solvents. It also has the added advantage of being durable.

Example 8 4 of the liquid polyester resin composition of Example 1
Doctor a ~5 mil layer onto the film covering the Bychrome screen negative. Next, 38.5 parts of the prepolymer used in the polyester resin composition of Example 1 and 41.08 parts of the prepolymer used in the preparation of the polyurethane resin composition of Example 3 were mixed with n-
Butylacrylamide 16 parts, 2-hydroxyethyl methacrylate 12 parts, styrene 5 parts, acrylamide 5 parts di-t-butyl p-cresol 0.04
0.04 parts of hydroquinone methyl ether, 0.65 parts of benzoin isobutyl ether, and 0.55 parts of α,α-dimethoxyphenylacetophenone.
0.23 mm) is doctored onto the above polyester resin composition. The plate is cured by exposing for 10 seconds from the support sheet side and 80 seconds from the negative side as described in Example 1. When the plate is developed as described in Example 1, it has the finely finished relief elements characteristic of the plates described in this invention.

Example 9 Hardness after curing is 22A and modulus is 150psi
(10.5 Kg/cm ² ) of the liquid polyurethane resin composition described in Example 5,
Doctor on a polypropylene film covering a production type negative for printing on cardboard boxes. 70 parts of the prepolymer used in the preparation of the polyurethane resin composition described in Example 4 were mixed with 12 parts of n-butylacrylamide, 6 parts of 2-hydroxyethyl methacrylate, 6 parts of tetraethylene glycol dimethacrylate, 2 parts of styrene, and methyl hydroquinone. 0.05 part of ether, di-t-butyl p-
A liquid polyurethane resin composition prepared by adding 0.05 part of cresol and 0.3 part of α,α-dimethoxyphenylacetophenone (a photocurable polymer with a hardness of 50 A and a modulus of 420 psi = 30 Kg/cm ^{2 )} A 125 mil (3.18 mm) thick layer of the resulting polyurethane composition is doctored onto the above polyurethane composition layer and the support sheet described in Example 1 (without antihalation red dye) is applied. The plate is cured by exposing it to light for 25 minutes from the support sheet side and for 5 minutes from the negative side.
A 250 mil (6.35 mm) thick plate with 125 mil (3.18 mm) relief was developed as above and
It has a solid relief element with a precision finish. This printing plate is used for printing on cardboard boxes. The solid areas printed with this plate hold the ink better than those printed with a 250 mil thick plate with only a polyurethane composition (ie, not a two-layer plate).

Example 10 1313 g in 2 resin kettles (polymerization flasks) equipped with stirrer, thermometer, gas inlet and outlet tubes
carboxyl-terminated copolymer of butadiene and acrylonitrile (acid number 31.9) containing 10% acrylonitrile (0.745 eq) and 77.8 g (0.48 eq) diglycidyl ester of bisphenol A and 3.3
g of N,N-dimethylbenzylamine is added.
The reaction mixture is kept at 100° C. for 7 hours under a nitrogen atmosphere. The acid value will be 9.4. Sparge dry air into the reaction mixture for 20 minutes and add a solution of 58.3 g glycidyl methacrylate, 3.9 g butylated hydroxytoene, and 0.078 g phenothiazine to the flask, hold at 100° C. for an additional hour, and cool.

The product has an acid number of 2.7 and a Bruckfield viscosity of 70000 cps at 25°C.

256 g of this prepolymer was mixed with 80 g of lauryl methacrylate, 64 g of 1,3-butylene glycol dimethacrylate, and 2.4 g of 2,2-dimethoxy-2-phenyl acetophenone at 40°C until a homogeneous solution was obtained (approx. 1 hour) to obtain a photosensitive composition.

After curing this by UV irradiation, the resulting resin has a tensile strength of 880psi (62Kg/cm ² ) and an elongation.
120%, tensile modulus 644psi (45Kg/cm ² ),
It has a shore hardness of 55A. When a sample of this cured resin is immersed in a solution of 90% ethyl alcohol and 10% propyl acetate for 24 hours, there is only a 13% weight gain.

A 5 to 15 mil layer of this liquid poly(butadiene-acrylonitrile)-based resin composition is doctored onto a polypropylene film overlying a line drawing negative original and when cured has a hardness of 40A and 220 psi.
The liquid polyurethane composition having a modulus of (15.5 Kg/cm ² )
Doctored onto the resin composition. The plate is exposed for 2 minutes through the backing sheet of Example 1 containing no antihalation dye and for 5 minutes through the negative. Warm this plate (50℃) with 1.0%
Bioorge alpha-olefin sulfonate detergent (Stepon
Chemical Co.) solution by spray cleaning and development.
Post-exposure for an additional 10 minutes under a nitrogen atmosphere. This plate, 90 to 95 mil thick with 45 mil relief, has the overall printing properties of the example plates described above, plus the advantage of resistance to alcohol, ink, and solvents. Exhibits exceptional resistance to delamination of the resin layer over long periods of time when used as a printing plate.

[Brief explanation of the drawing]

The accompanying drawings show a partial cross-sectional view of a printing plate made according to the present invention. 1... Support sheet, 2... Lower layer group, 3... Upper layer (printing layer).

Claims (1)

[Scope of Claims] 1 (A) One or more ethylenically unsaturated groups having a normal boiling point higher than about 100°C, a molecular weight less than about 1500, and capable of forming a high polymer by photoinitiated polymerization. at least one addition-polymerizable compound having; at least one unsaturated polymeric substance soluble in the addition-polymerizable compound;
a printed layer comprising a liquid photopolymerizable composition containing at least one polymerization inhibitor; and a photopolymerization initiator, and may further contain an ultraviolet absorber; (B) a normal boiling point of about 100°C or higher; high, with a molecular weight of approx.
At least one addition polymerizable compound having one or more ethylenically unsaturated groups of less than 1500 and capable of forming a high polymer by photoinitiated polymerization; soluble in this addition polymerizable compound. from another liquid photopolymerizable composition containing at least one unsaturated polymeric type substance; at least one polymerization inhibitor; and a photoinitiator, and may further contain a UV absorber. The photopolymerizable element containing the base layer is exposed to actinic light through a photographic original plate, unpolymerized portions of each layer are removed, and the concentration of at least one of a photoinitiator, a polymerization inhibitor, and an ultraviolet absorber is adjusted. A process for producing a printing plate in which the base layer has a photopolymerization rate at least 1.5 times that of the printing layer, comprising: (i) adjusting the degree of unsaturation of the unsaturated polymer type material; Selective use of an addition polymerizable compound (iii) Adopting at least one means of adjusting the amount of the addition polymerizable compound so that both compositions constituting the printing layer and the base layer have at least a modulus of both layers after exposure. Approximately 50psi (3.5Kg/cm ² )
A method for producing a printing plate characterized by producing a difference in 2. The method according to claim 1, comprising:
The unsaturated polymeric materials include unsaturated polyesters, unsaturated polyester-polyether block polyurethanes, unsaturated polyether-polyurethanes, and unsaturated homopolymers and copolymers of butadiene, isoprene, chloroprene, styrene, isobutylene, ethylene and acrylonitrile. A method of being selected from a group of 3. The method according to claim 1, comprising:
A method in which the photopolymerization initiator is selected from the group consisting of alkylbenzoisoether and α,α-dimethoxyphenylacetophenone. 4. A method according to claim 3, comprising:
A method in which the photopolymerization initiator content is about 0.1 to 1% by weight in the printed layer and about 0.5 to 2.5% by weight in the base layer. 5. The method according to claim 1, comprising:
A method in which the modulus of the printing layer is higher than that of the base layer. 6. The method according to claim 1, comprising:
A method in which the modulus of the base layer is higher than the modulus of the printing layer.