GB2134275A

GB2134275A - Photosensitive resin compositions

Info

Publication number: GB2134275A
Application number: GB08401661A
Authority: GB
Inventors: Takeo Kuramoto
Original assignee: WR Grace KK
Current assignee: WR Grace KK
Priority date: 1983-01-28
Filing date: 1984-01-23
Publication date: 1984-08-08
Also published as: IT1206696B; JPS59137943A; IT8419349A0; GB2134275B; GB8401661D0; CA1232915A; AU556611B2; AU2371684A; DE3402465A1; NL8400257A

Abstract

A fluorocarbon surfactant having a C4-C14 perfluoroalkyl group reduces contamination in resin based printing plates when combined with the photosensitive resin and eliminates the need to separately pretreat the plates. The surfactant is preferably nonionic.

Description

SPECIFICATION Photosensitive resin compositions The present invention relates to a surfactant which when used in combination with a photosensitive resin composition in a high-speed rotary press printing plate, reduces or prevents contamination. The present invention is particularly useful with a photosensitive resin composition used to make a newspaper printing plate.

In the past, the plates generally used in high-speed rotary presses used by newspapers were metal, e.g. lead. In recent years the trend has been away from such conventional metal plates and towards use of resin based plates. The resin based letterpress plates are such that a photosensitive resin composition is irradiated with an actinic light beam through a negative film to cure the photosensitive resin. Thereafter, a cured resin is developed by various means, thereby forming a letterpress image. The resin based letterpress plates are recognized as having advantages because of the increased ease of handling based on their light weight.Although the resin based plates are easier to work with, thqy have the disadvantage of becoming contaminated (hereinafter referred to as "contamination") in the dots, especially on the photographic face, in the course of printing. Although the mechanism of this contamination is not fully understood, when this phenomenon occurs ink and paper dust will accumulate in the valley (concave) portions of the relief plate and the quality of the normal dot (photograph) is impaired.

In the past, contamination was prevented by separately treating the resin plates with surface agents which were made by dissolving silicone oil in a hydrocarbon solvent or with agents that were water and oil repellent. However, it was found that agents made by dissolving silicone oil in a hydrocarbon solvent were not sufficiently durable because they dissolved easily in the ink.

As a result, contamination occurred after about 20,000 impressions were made. Further, the latter type of agent is not effective unless complete heat-curing is conducted after pre-treating with the agent. Additionally, even if the agent is heat-cured its durability is not always satisfactory and contamination still occurs after printing about 30,000 impressions.

It is an object of this invention to reduce or prevent contamination of resin based printing plates, especially letterpress plates, and to avoid the other problems discussed above.

A composition according to the invention for use in a resin-based printing plate comprises a photo-sensitive resin and a fluorocarbon surfactant having a C4 t4 perfluoralkyl group.

A resin based printing plate according to the invention is one in which the resin composition includes the said fluorocarbon surfactant. Before exposure, the resin is photosensitive.

The invention includes also the use of the said fluorocarbon surfactant for reducing contamination in resin based printing plates, and a method of reducing contamination of resin based printing plates by including the said surfactant in a photosensitive resin composition.

The plate is preferably a letterpress plate and it displays a remarkable contamination preventing effect, i.e. an increase in the number of impressions that can be made without evidencing any contamination. Use of the composition of this invention renders quite unnecessary such conventional operations as preliminary surface treatment. By virtue of use of this composition it is possible to subject the above letterpress plate to printing merely by mounting it on a rotary press.

The fluorocarbon surfactant contains at least one C4-Cr4 perfluoroalkyl group. A mixture of surfactants may be used. The sufactant is preferably contained in the photosensitive resin composition in amounts of about 0.001 wt % to about 5 wt.%. If the content is less than about 0.001 wt% its effect becomes poor. Preferably the amount is at least 0.01%. If the amount exceeds about 5 wt.% the composition will still be useful but will be less effective, since its ink repellency becomes too strong with the result that the photographic printing effect become poor.

Additionally, if the content exceeds about 5% the cost becomes economically disadvantageous.

The fluorocarbon surfactant is preferably nonionic. However, it has also been found that an anionic, cationic or ampholytic fluorocarbide surfactant is also effective to prevent contamination. However, compounds having these ionic properties are generally not preferred because it is difficult to maintain their stability with time after they have been combined with a photosensitive resin composition. In the case of a liquid photosensitive resin composition, thickening or gellation is likely to occur. Further, if the photosensitive resin composition is solid such agents are likely to cause problems such as inability of development.

Examples of the fluorocarbon surfactants used in the present invention include (2-perfluorooctylethyl polyoxypropylene ether carba myl)-polyoxyethylenecarbamyltoluene, 2-perfluorooctyl- 1 - acetoxymethylethyl carbamyltolylenestearyl polyoxyethylene carbamate, 2-perfluoroalkyl (C4-C,4) ethanol, 2-perfl uorooctyl- 1 -methylethyl polyoxyethylene ether, perfluoroisopropoxypropylcilsesquinoxane.

The present invention includes photosensitive resin compositions, which are liquid or solid at room temperature. A preferred liquid type photosensitive resin includes predominantly a polyurethane, polyester or synthetic rubber. Further, a preferred solid type photosensitive resin includes mainly polyvinyl alcohol or nylon. Of course, neither the liquid or the solid resin is restricted to the above examples.

The present invention is exemplified by the following Working Examples and Comparative Examples.

Example 1 60 g of urethane type prepolymer obtained by the thermal reaction of polyoxypropylene glycol (molecular weight of 1000), tolylene diisocyanate and hydroxyethyl methacrylate, 35 g of diethylene glycol dimethacrylate and 5 g of pentaerythritol tetrakis (B-mercaptopropionate) were mixed with 0.5 g of hydroquinonemonomethyl ether as the thermal polymerization inhibitor and 1 g of benzoin ethyl ether as the sensitizer. There resulted 101.5 g of urethane type photosensitive resin composition for letterpress printing.

To this composition 0.5 g of 2-perfluorooctyl-1-methylethylpolyoxyethylene ether was added and then mixed. The mixture exhibited good storage stability. When this mixture was used in a newspaper rotary press, no contamination occurred until 60,000 impressions were made.

Example 2 To 101.5 g of the same urethane type photosensitive resin as in Example 1, 0.5 g of (2perfluorooctylethyl polyoxypropylene ether carbamyl)-polyoxyethylenecarbamyltoluene, was added and then mixed. The mixture exhibited good storage stability. When this mixture was used in a newspaper rotary press, no contamination occurred until 60,000 impressions were made.

Example 3 An unsaturated polyester was produced by the thermal reaction of dimethyl terephthalate, diethylene glycol, propylene glycol, 1, 4, 8-naphthalene tricarboxylic acid anhydride and citraconic acid anhydride. To 70 g of this resin 30 g of acrylamide, 0.01 g of hydroquinone and 0.7 g of benzoin were added to produce a polyester type photosensitive resin. Further, 0.5 g of the same fluorocarbide surfactant as that in Example 2 was added to this resin. A printing plate produced using this mixture was used in a newspaper rotary press and no contamination occurred until 50,000 impressions were made.

Example 4 A solid polyvinyl alcohol type photosensitive resin was produced by mixing 60 g of polyvinyl alcohol, 30 g of hydroxyethyl methacrylate, 0.1 g of hydroguinone, 5 g of benzyl dimethyl ketal and 0.5 g of the fluorocarbide surfactant used in Example 2. This blend had good storage stability. A printing plate produced from this mixture was used on a press and no contamination occurred until 50,000 impressions were made.

Comparative Example 1 In the case of a urethane type plate prepared without using the fluorocarbide surfactant of Example 1 contamination occurred at the time 10,000 impressions were made.

Comparative Example 2 In the case of a polyester type plate produced without using the fluorocarbide surfactant of Example 3 contamination occurred at the time 8,000 impressions were made.

Comparative Example 3 In the case of a polyvinyl alcohol type plate produced without using the fluorocarbide surfactant of Example 4 contamination occurred at the time of 8,000 impressions were made.

Examples 5-16 and Comparative Examples 4-7 A printing plate was produced from a composition and used in a newspape rotary press, said composition being obtained by mixing each of the following nonionic fluorocarbide surfactants A-F in fixed amounts with various resins as shown in Table 1. The number of impressions made without detection of contamination and the photographic printing effect are shown in Table 1.

Surfactant A: 2-perfluorooctyl- 1 -methylethyl polyoxyethylene ether; B: (2-perfluorooctylethyl polyoxypropylene ether carbamyl)polyoxyethylenecarbamyltoluene; C: 2-perfluorooctyl- 1 -acetoxymethylethyl carbamyl-tolylenestearyl polyoxyethylene carbamate; D: 2-perfluorooctyl ethanol; E: perfluoroisopropoxypropylcilsesqu inoxane; and F: perfluorooctanesulfonic acid diethanolamide Number of Impressions Photo with contami- graphic Carbide Content nation not printing Ex. No. Surfactant (wt.%) Resin detected effect Comp. A 0.0005 Urethane type 10,000 Good Ex. 4 in Example 1 Ex. 5 A 5 ,, 65,000 Good ,, 6 A 7 65,000 Poor Comp.B 0.0005 ,, 10,000 Good Exp. 5 Ex. 7 B 5 ", 1 65,000 Good " 8B 7 /, 65,000 Poor 9 C 0.5 ,, 65,000 Good 10 10 D 0.5 ,, 60,000 Good ,, 11 E 0.5 ,, 60,000 Good 12 12 F 0.5 ,, 65,000 Good 13 13 C 0.5 Polyester type 50,000 Good in Example 3 14 14 D 0.5 Polyvinyl 60,000 Good alcohol type in Example 4 ,, 15 E 0.5 Nylon type 60,000 Good 16 16 F 0.5 Synthetic 50,000 Good rubber type Comp.Not used - Nylon type 10,000 Good Exp. 6 " 7 Not used - Synthetic 5,000 Good rubber type The nylon type resins, see Example 15 and Comparative Example 6 in Table 1 comprise 100 wt. parts of a copolymer polyamide of N-bis(2-aminoethyl)methylamine, adipic acid and ecaprolactam, 5 wt. parts of methylenebis acrylamide, 0.1 wt. part of hydroquinone and 1 wt.

part of benzoin. Table 1 shows that when the fluorocarbide surfactant of the present invention is used as in Example 15, 60,000 impressions were made without detection of contamination, whereas without the surfactant only 10,000 impressions were made as illustrated by Comparative Example 6.

The synthetic rubber type resins, see Example 16 and Comparative Example 7, comprise 100 wt. parts of a styrene-butadiene type block copolymer (styrene content: 35-50 wt.%), 20 wt.

parts of 1,6-hexanediol diacrylate, 0.5 wt. part of tertiary butylphenol and 1 wt. part of benzoin ethyl ether. Table 1 shows that when the surfactant of the present invention is used as in Example 16, 50,000 impressions were made with no contamination detected, whereas without the surfactant only 5,000 impressions were made as illustrated by Comparative Example 7.

Claims

1. A composition suitable for use in a resin based printing plate comprising a photosensitive resin and a fluorocarbon surfactant having a C4-C,4 perfluoroalkyl group.

2. A composition according to claim 1 wherein the fluorocarbon is nonionic.

3. A composition according to claim 1 or claim 2 wherein the amount of surfactant is from 0.001% to about 5% by weight of the composition.

4. A composition according to any preceding claim wherein the surfactant is selected from 2-perfl uorooctyl- 1 -methylethyl polyoxyethylene ether, (2-perfluorooctylethyl polyoxpropylene ether carbamyl)-polyoxyethylenecarbamyltoluene, 2-perfluorooctyl carbamate, 2-perfluorooctyl ethanol, perfluoroisopropoxypropycilsesquinoxane, perfluorooctanesulfonic acid diethanolamide, and mixtures thereof.

5. A resin based printing plate in which the resin composition comprises a resin and a fluorocarbon surfactant having a C4-C,4 pefluoroalkyl group.

6. A plate according to claim 5 wherein the fluorocarbon is nonionic.

7. A plate according to claim 5 ro claim 6 wherein the amount of surfactant is from 0.001% to about 5% by weight of the composition.

8. A plate according to any of claims 5 to 7 wherein the surfactant is selected from 2 perfluorooctyl-1-methylethyl polyoxyethylene ether, (2-perfluorooctylethyl polyoxpropylene ether carbamyl)-polyoxyethylenecarbamyltoluene, 2-perfluorooctyl carbamate, 2-perfluorooctyl ethanol, perfluoroisopropoxypropycilsesquinoxane, perfluorooctanesulfonic acid diethanolamide, and mixtures thereof.

9. A plate according to any of claims 5 to 8 in which the resin is photosensitive.

10. A surfactant for reducing contamination in resin based printing plates usable in a photosensitive resin composition and which is a fluorocarbon surfactant having a C4-C14 perfluoroalkyl group.

11. A surfactant according to claim 10 wherein the fluorocarbon is nonionic.

12. A surfactant according to claim 10 to claim 11 wherein the surfactant is selected from 2-perfluorooctyl- 1 -methylethyl polyoxyethylene ether, (2-perfluorooctylethyl polyoxpropylene ether carbamyl)-polyoxyethylenecarbamyltoluene, 2-perfluorooctyl- 1 -acetoxymethylethyl carbamyltolylenestearyl polyoxyethylene carbamate, 2-perfluorooctyl ethanol, perfluoroisoproppoxypropylcilsesquinoxane, perfluoro-octanesulfonic acid diethanolamide, and mixtures.

13. A method of reducing contamination of resin based printed plates comprising including in a photosensitive resin composition a fluorocarbon surfactant having a C4-C14 perfluoroalkyl group.

14. A method according to claim 13 wheren the fluorocarbon is nonionic.

15. A method according to claim 13 or claim 14 wherein the amount of surfactant is about 0.001% to about 5% by weight of the resin composition.

16. A method according to any of claims 13 to 15 wherein the surfactant is selected from 2-perfluorooctyl- 1 -methylethyl polyoxyethylen ether, (2-perfluorooctylethyl polyoxypropylene ether carbamyl)-polyoxyethylenecarbamyltoluene, 2-perfluorooctyl- 1 -acetoxymethylethyl carbamyl-tolylenestearyl polyoxyethylene carbamate, 2-perfluorooctyl ethanol, perfluoroisopropoxypropylcilsesquinoxane perfluorooctanessulfonic acid diethanolamide and mixtures thereof.