JPS5926264A - Offset printing - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a repetitive offset printing process of the type in which ink designs are transferred to articles using deformable fjP pads.

Offset transfer pad methods for printing on multiple shapes are well established in the ceramic, plastic, toy and packaging industries. Most of these methods use a pad of deformable gelatin or stylus to transfer the ink design from the metal intaglio to the item to be decorated or sold. Metal intaglios can be engraved or etched.

These metal intaglio costs can be high, especially when engraved by hand. British Patent Specification No. 737.461 proposed the use of K, a silk screen and an intermediate flat surface instead of a metal intaglio. The ink design is applied by screen printing to an intermediate flat surface and then transferred by a deformable pad to the article to be sold or decorated. It was suggested that the intermediate surface could be any non-absorbing material, and examples were given of metal and glass. However, in practice, the ink film on the intermediate surface was found to tear when the deformable pad was removed from the intermediate surface. As a result, the ink in the design spread with successive prints and lost definition.

British Patent Specification No. 1,602,225 discloses that in order to overcome said problems and eliminate the risk of excessive build-up of ink on intermediate surfaces, in each silkscreen printing operation:
It has been found necessary that the intermediate surface be free of residual color remaining from previous printing. To achieve this, intermediate surfaces can be knife coated between successive prints, or paper can be fed half size from a roll so that a fresh area of paper is provided for each screen printing run. Let's make it clear.

When using knife coating, the efficiency of the knife coating is critical and care must be taken to prevent scratching of the intermediate surface. Failure of knife application efficiency or scratch prevention will immediately result in print failure.

Even with all of Gyochi's methods, an additional disadvantage arises that each transfer operation tears the ink film and only a portion of the ink is transferred to the workpiece.Especially in the case of ceramics, the colorant It is necessary to be able to print large blocks or strips of paper, and this is difficult to achieve even with the Lewinki split method.

The present invention stems from an attempt to provide an improved offset printing process in which the ink design on the intermediate surface is substantially completely transferred by means of deformable knots onto articles to be marketed or decorated.

British Patent Specification No. 804,751 suggests that the transfer of the entire design from the intermediate surface to the article to be printed can be carried out by covering both the intermediate surface td and the elastic pad with an adhesive layer. There is.

The fact that this proposal has not been commercially developed casts doubt on the effectiveness of the method.

The present invention improves the relative affinity of ink to the intermediate surface, deformable pad, and workpiece by adjusting the relative affinity of the ink to the intermediate surface, the deformable pad and the workpiece.
Based on the discovery that this can be controlled by the use of different types of silicone rubbers, these silicone rubbers differ from those in which the catalyst is used to cure the rubber.

U.S. Pat. No. 4,261,749 relates to thermoplastic ink formulations for use in an offset process in which an ink design is applied to the intermediate surface of a silicone elastomer and then transferred to an article by another silicone elastomer. Column 4, lines 47-51 states, "It is desirable to make the difference in surface energy between the two silicone surfaces as large as possible to facilitate the release of ink from one to the other." However, it does not specify in detail what kind of rubber should be used. It appears that by using rubbers of different composition it was intended to vary the surface energy, for example by varying the phenyl/methyl ratio, as is known in the art.

Furthermore, in column 4, lines 54-58, it is stated that [according to the material of the invention, the replacement of the silicone roll or) ξrad is
less than required for other currently available thermoplastic ink formulations" and column 4, item 5.
Lines 0-52 each state, "It has been invented that the surface energy of silicone increases with repeated release cycles."

Thus, while U.S. Pat. No. 4,261,249 is concerned with inventing ink formulations that accommodate changes in ink affinity on the surface of silicone rubber that occur in use, the present invention is directed to It is concerned with substantially stabilizing the ink compatibility of the two surfaces so that replacement, if any, to alter the ink compatibility is rarely required.

According to one aspect of the invention, an ink design is first applied to an intermediate surface and then transferred from said intermediate surface to the article by means of a deformable pad, said intermediate surface and Nomurad each having a 1 and a second silicone rubber, the first and second imes employ different catalysts in their curing, and the catalyst is such that the affinity of the first silicone rubber for the ink is greater than the affinity of the second silicone rubber for the ink. Provided is a repetitive offset printing method, characterized in that it is selected to have substantially less affinity for.

The intermediate surface is preferably flat.

As will be explained in detail below, if the catalyst used for silicone rubber curing is appropriately selected and the viscoelasticity of the ink is appropriately controlled, the ink can be used to cure the workpiece from the intermediate surface of the pattern.
The transfer rate of ~ can be set to 100%. then,
Since there is no need to knife the intermediate surface, the printing device can be made very simple and reliable.

The ink design can be applied to the intermediate surface by any suitable method. Preferably, a silk screen method is used, but other screen printing methods can be used.

Condensation type silicone rubber which has compatibility with a wide range of inks, A heavy metals as catalysts, such as Ph,
Zn, Zr, Sb, Fe1Cd, Sn,,
By the use of carboxylic acid salts of B(Z, Ca, and Mn), a range of ink compatibility is provided in particular in the manufacture by the following list of salts: naphthenic, octanoic, hexanoic acid salts of metals. salts, laurates and acetates.The affinity in the ink generally decreases through this list.

In theory, it would seem best to take both ends of the predistribution strike and use a metal acetate to cure the first rubber and a metal naphthenic acid to cure the second rubber. However, in practice, partly due to labor availability, both rubbers are of the condensed type; metal laurate is used for the first rubber, and metal octanoate is used for the second rubber. It is preferable to do so. Attempts have been made to use the first rubber, acetate, but the resulting rubber is slightly unstable, thereby limiting its commercial potential.

On this scale of ink affinity, there is an upper limit for hardened rubber.

Condensation-type silicone imes have much less affinity for dibutyltin laurate as a catalyst in the curing process than for condensation-curing rubbers using other catalysts such as l-dibutyl in the curing process or in addition-curing rubbers. I discovered that it has.

When a contact cured rubber using dibutyltin dilaurate as a catalyst is used for the intermediate surface, it is preferable to use a condensation cured rubber for the pad using stannous octoate as a catalyst. This method can be effectively carried out using addition-cured rubber to , ξrad.

We have also discovered that it is preferable to heat treat the dibutyltin dilaurate silicone rubber after curing to stabilize the ink's affinity with other silicone rubbers.

Because of its lower affinity for ink, the stabilized dibutyltin dilaurate-catalyzed silicone im provides an ideal material for the intermediate surface.

It accepts ink from the silk screen to form a high definition pattern, but subsequently (on pressure contact, a deformable patch of suitably dissimilar silicone imm) may also be used due to differences in ink affinity. , that's the ink pattern 10.
Give 0% to ξtsupihe.

When using screen printing on the intermediate surface of the design,
It is preferable to change the viscoelasticity of the ink between the screen printing stage and the ink pattern transfer stage. The need for this change is that the viscoelastic properties of the ink required for screen printing differ from those desired for good transfer. Ink of the correct viscosity is the tenth essential consideration for quality screen printing, whereas ink tack can be important in transfer. This critical change from screen printing viscosity to transfer tackiness is preferably achieved by the use of heat.

Electrically heated metal screens are conveniently used, but externally heated screens can be used.

In addition, the ink should be compatible Vμ to the silicone rubber of both the transfer, ξrad and intermediate surfaces;
It must not induce significant deterioration during the printing period. An ink that satisfies all the above criteria is preferably a solid resin,
It was found to be composed of liquid resins, waxes and ceramic pigments.

The wax should have a melting point below the desired silkscreen temperature and the solid resin should have a melting point above this temperature. Viscosity control in silkscreening is accomplished by adjusting the solid/liquid resin ratio and tackiness at the transfer stage through the wax to total resin ratio.

According to a second aspect of the invention, an intermediate surface, means for applying an ink pattern to said intermediate surface, a deformable pad, and aligning said deformable pad with said intermediate surface;
means for picking up an ink design; and means for aligning said pad carrying an ink design with an article to transfer the ink design to the article; a second silicone rubber, the first and second rubbers employing different catalysts in their curing, and the catalyst is such that the affinity of the first silicone rubber for the ink is different from that of the second silicone rubber. Offset printing 11 is suitable for use in printing on curved surfaces of articles, characterized in that it has a substantially lower affinity for ink.

In a preferred embodiment of the invention, the electrically heated metal screen and the ink formulation are used such that at the temperature of the screen, the viscosity of the ink is corrected for screen printing. screen imprinting ink in the form of a pattern on the intermediate surface of the stabilized digityltin dilaurate catalyzed silicone rubber;
II [, the intermediate surface is heated to a lower temperature than the screen, thus allowing the tackiness of the ink to prevail after the double print. 100% of the ink design is picked up from the intermediate surface using a modified pad of silicone rubber similar to one, for example, addition hardness or octanoate catalyzed condensation cured silicone rubber. . In the final stage of this operation, knot 5 transfers 100% of the ink design to the workpiece. This method is diagrammatically illustrated in a single additional figure. In this drawing,
The reference numeral 1 indicates the heated silk screen, 2 indicates the ink pattern, the filter indicates the heated intermediate surface,
4 indicates the deformable pad and 5 indicates the workpiece.

The following examples demonstrate the principles of the invention and illustrate details regarding silicone rubber and ink formulations, screen and intermediate surface operating temperatures.

Silicone rubber transfer pad (A1) Addition curing.

Weight part rubber polymer 4O-6
05Qcst silicone fluid 60
-40% by weight, ro IJ mama -11,1% manufacturer's crosslinking agent and catalyst 4.4-
6.68 Rubber polymer ME supplied by the following companies:
Based on 622: Wacker Chemicals (UK) Li
d.

The C1ock Tower Mount Fe1ix Brid, quest Walton-on-Thames, 5rtrre
y K'r121. As) (A2) Condensation ratio 8: parts by weight of polymer 6O
-9050c, ftσ le/recone fluid
Based on 40-10 weight, ru IJ Mama-0,5
~2% ethyl silicate
0.3-1.8 hand lX chemistry, 0.3-2% of lr rimmer
of stannous octoate 0.18
-1.88 Rubber polymer 5 supplied by the following companies:
．． Rhodia (UK) Ltd.

Hwlton Hol7.5e 161-166 Fleet 5treetLONDO
N EC42DP) Example of a silicone rubber intermediate surface (B1) Rubber polymer silicone set 105 supplied by the following company: ICI Corporation (ICILtct.

Organicx Diυision Blackle
y MANCHESTER,) parts by weight rubber polymer 6O-1
0050cst silicone fluid 4
0-0 0.1-6% dibutyltin dilaurate and crosslinking agent by weight of polymer 0.06-
5 (B2) Rubber 7P reamer supplied by the following company
Rhodia (UK) T-t4Hu, 1to based on 573A
rLHou, 5e 161-166 Fleet 5treetLONDO
N EC42DP) Part by weight Rubber polymer 8O-1
005Qcst silicone fluid 2
0-0.5-6% of dibutyltin dilaurate and additives in the polymer on a 0-by-liter basis 0.4-
5 The rubber of Example (B1) or (B2) is produced as a thin uniform layer on a metal backer with a thickness of 0.5 to 5+ nm ('l"). After fabrication and curing, the rubber is
It becomes stable and strong by heat treatment at ℃ for 4 hours.

Example of ink formulation (C) Heavy 1 part stabelite ester 8411 effect (E3ta, ybelite Ester Rey
i, n) 5 64.8 Stabellite ester resin 10 17.6 Polyethylene glycol 15[1[117,<S pigment 2
00.0 The ink is manufactured by homogeneous mixing in a beat or three roll mill.

Staybelite resin is supplied by the following companies: Hercules Lf, d.

20, Red Lion 5treetLONDON
WClF (4PB) Typical Operating Temperature Silkscreen 60-10
0°d intermediate surface 50
-45°C

[Brief explanation of the drawing]

The drawing is a diagram illustrating the method of the invention. 1. Heated silk screen 2. Ink pattern 6. Heated intermediate surface 4. Deformable pad 5. Engraving of workpiece drawing (no change in content) Continued from page 1 @) Inventor Wilfred Roberts UK Staff 43 Naples Drive, Westlands, Newcastle Ampoo Rim, Ordshire Procedural Amendment (Type 11) 1. Indication of the incident Showa U,
No.〉1゛7人・Lfp is “)Relationship with the case of the person who makes the amendment Applicant Address: I1, Bribui I.U.Fumi,・7
・Rizukepaj-“17 Aen 3/・Limite,-・F
'4, agent

Claims (1)

Claims: 1. An ink design is first applied to an intermediate surface and then transferred from said intermediate surface to an article by a deformable pad, said intermediate surface and pad being respectively a second silicone rubber, the first and second rubbers employ different catalysts in their curing, and the catalyst is such that the first silicone rubber's affinity for the ink is different from the second silicone rubber's affinity for the ink. a repetitive offset printing method, characterized in that the repeat offset printing method is selected such that: 2. The first silicone rubber is of the condensation type, and the catalyst used for curing the rubber is a metal carboxylate.
A method according to claim 1. 3. The method according to claim 2, wherein the salt is a metal laurate. 4. 5) according to claim 6, wherein the salt is dinotyl Kanagawa dilaurate. )in. 5. The method according to claim 4, wherein the salt is dibutyltin dilaurate. 6. The method according to any one of claims 1 to 5, wherein the second silicone rubber is an addition cured rubber. 7. The method according to any one of claims 1 to 5, wherein the second silicone rubber is a condensation type, and the adhesive used for curing the rubber is a metal carboxylic acid. 8. The method according to any one of claims 3 to 5, wherein the second silicone rubber is a condensation type, and the catalyst used for curing the rubber is metal octo-1. 9. The method according to claim 8, wherein the metal octoate is stannous octoate. 10. The method according to any one of claims 1 to 9, wherein the first silicone rubber is heat treated after curing to substantially stabilize its ink affinity. 11. A method according to any one of claims 1 to 10, wherein the ink design is applied to the intermediate surface by silk-screening. 12. The method of claim 11, wherein the silk screen and the intermediate surface are maintained at a temperature above ambient temperature, the temperature of the silk screen being higher than the temperature of the intermediate surface. 13. The method of claim 12, wherein the silk screen is maintained at a temperature in the range from 60 to 100C and the intermediate surface is maintained at a temperature in the range from 0 to 450C. 14. A method substantially as described in the specification, wherein the material of the intermediate surface is substantially as specified in Example (B1). 15 A method substantially as described in the specification, wherein the material of the intermediate surface is substantially as specified in Example (B2). 16. The material of the pad is the visually cured rubber substantially specified in Example (A1). Claim 17: The material of pad 8 is the condensation cured rubber substantially specified in Example (A2). Claim 14 or 1
The method described in Section 5. 18. The ink is produced by the method described in the specification 111' in which the formulation is practically specified in Example (Q). 19. 20. An intermediate surface, means for applying an ink design to said intermediate surface, a deformable pad, and said deformable pad in conjunction with said intermediate surface. , a means for picking up the ink pattern, and an ink pattern?
means for transferring the ink design to the article by aligning the ξrad with the article in register; the intermediate surface and pad are formed of first and second silicone rubber, respectively; , the first and second rubbers also use different catalysts in their curing, and the catalysts are such that the first silicone rubber has substantially less affinity for the ink than the second silicone rubber for the ink. An offset machine suitable for use in printing onto curved surfaces of articles, characterized in that: 21. The machine of claim 20, wherein the first silicone rubber is of the condensation type and the catalyst used to cure the rubber is a metal carboxylate. 22. The machine of claim 21, wherein the salt is a metal laurate. 23 The above j value is dibutyltin dilaurate,
A machine according to claim 22. 24. The second silicone rubber is of the condensation type, and the catalyst used for curing the rubber is a metal carboxylate;
A machine according to claim 22 or 26. 25. The machine according to claim 24, wherein the metal octoate is stannous octoate.