DE202010011606U1 - Printing pad for pad printing - Google Patents

Abstract

Printing pad for pad printing, characterized in that it consists of a pourable, soft elastic, plastically deformable silicone rubber.

Description

The The present invention relates generally to printing processes. Especially The invention relates to a pad printing method. Especially concerned the invention is a printing pad for such a pad printing process.

The Pad printing process is an indirect gravure printing process that was developed to existing printing systems such as screen or To complement embossing. Almost independent of shape and surface structure (concave, convex, curved Surfaces) can be used for a wide range of materials, also mechanically sensitive products such. Eg eggs or glass, be printed.

The The printing form (cliché) bears in its surface the lower printed image to be printed. A squeegee pushes the applied color in the deeper printed image and a Doctor blade cleans the excess paint clean from. Thus, a color film remains in the recesses. After or at the same time with the doctor blade moves, usually Made of silicone rubber, tampon from Druckgut to form. The tampon is lowered over the cliché and takes over so the print picture. Then the tampon is lifted and moves to the substrate, whereupon he then in a rolling motion is pressed. In this way, the color of the substrate issued. As a substrate can be almost every Material (wood, cardboard, paper, thermoplastics, polyolefins, thermosets, Metals, glass and the like).

printing pads (also called plunger or pressed bales) made of silicone rubber were developed about 30 years ago. The advantage is in the Deformability, reducing the printing of curved surfaces is possible. The tampon decreases due to its elasticity the shape of the body to be printed on and so can the Ideally transferred motif to the substrate. The color film then sticks due to the stickiness of the solvent evaporation on the substrate. In these operations, the tampon meet the most varied mechanical requirements, to ensure a precise pressure. The elastic deformability and the geometry of the printing pad must to be matched to the specific printing tasks.

Pad printing machines are, for example, from the WO 2004/113075 A1 , of the EP 1 053 882 A and the DE 20 2007 006 656 U1 known.

to Production of a printing tampon requires a prototype which can be made in various mechanical ways. This original form (blank) serves as a template for a casting mold, wherein the blank as a positive model and the mold as a negative model referred to as. When casting arises from a liquid Material after solidifying a solid body certain Shape. The mold is used in the manufacture of the printing pad filled with a mixture of liquid silicone rubber and covered. After curing, d. h., after doing so solidified that it is usable as a soft elastic tampon, The finished tampon is removed from the mold and cleaned.

For The building materials sector are so-called Knetsilikone as sealants known, which are offered as 1- or 2-component systems. These Although silicones are cheap and flexible, they have no silicone rubber properties on. Besides, they have a big inertia, d. h., An inappropriate for the pad printing recovery. Under Resilience is the property of a deformable substance to understand the original dimensions entirely or partially accept again after the forces lifted were that caused the deformation.

The Some of the kneading silicones used in dentistry have one high resilience and are rubbery, they However, as they are required for processing Dentists or dental technicians are provided and under Circumstances permanently in contact with human tissue be free of toxins and also odorless. Therefore These silicones cost a multiple of the silicones currently in the industry Pad printing can be used, their application is therefore uneconomical.

adversely On the mentioned kneading silicones is also that the development new printing pads by the production of the blanks and the respective new molds is costly. Thus, since the by far the largest amount of tampons a volume of up to a quarter of a liter, the prototype production means Casting very expensive. It also causes considerable problems with the waste disposal of the residual silicone, the can not be used in this type of production. In addition, the time required as an additional cost factor.

Of the The present invention is therefore based on the object, a printing pad to provide for the pad printing that mentioned Disadvantages of the prior art avoids.

These and other objects are provided by the printing pad according to claim 1 solved. Further advantageous embodiments are in set forth the subclaims.

So far, printing pads for the pad printing were produced exclusively by casting. The liquid casting compound of silicone rubber is poured into a mold and cured therein, ie, solidified so that the mass is useful as a soft elastic tampon. There are now thousands of tampon printing on the market, but constantly new forms are needed to solve specific printing problems. In particular, for the pad printing prototype construction production by casting compound is very expensive, since it raises major problems in terms of disposal of the residual silicone, which can not be used in this type of production.

According to the invention the printing pad is not cast as described above, but instead it becomes a pourable silicone rubber, i. H., uses a kneading silicone having a consistency such as soft dough or lava. The silicone rubber is in shape made of a rod, in particular extruded. Both become advantageous Components in a bar with inner core and sheath produced, with both components are not yet responding. It exists also the possibility that hardener and resin in two rods, in particular different colors are produced, of which one slice at a time is cut off. The one for one Pressure pad corresponding amount can be cut off the rack be, the cut off part is plastically deformed (kneaded) and pressed into a mold. The silicone compound in the form is free of air bubbles flowable. In the form of the silicone rubber then solidified so that the mass becomes doughy, d. h., as a soft elastic Tampon is usable.

Of the used silicone rubber can different Shore A hardnesses in the range of 3-30. Thus the kneading silicone free of air bubbles is the rubber advantageously has a Shore hardness from about 6-8.

Of the used silicone rubber advantageously has a high rubber elastic Resilience. He is not tragic. The silicone rubber used (Knetsilikon) can be added or be condensation-linked. While the addition crosslinking on the linking of Si-H groups with double bonds which, in addition to salts or complexes of platinum corresponding Palladium or rhodium compounds used as catalysts be, come in the condensation crosslinking catalysts such Dibutyltin dilaurate or tin (II) octoate used. They catalyze the reaction between α, ω-dihydroxypolydimethylsiloxanes with silicic acid esters.

Of the Pressure pad according to the invention can be a smooth or have a feinmattierte surface. this will achieved by sandblasting the mold or the model is.

Of Further, the printing pad according to the invention in a simple manner with and without plasticizer components, such as. Silicone oils, getting produced.

Around the kneading silicone as a tampon with repulsive properties to use solvent printing inks To be able to, the pure silicone portion in the ideal relationship must to the plasticizer, with a ratio of 1: 1 is desired.

by virtue of There is the diversity of today's solvent printing inks very aggressive color types as well as less aggressive pad printing inks. The kneading silicone is therefore according to the respective requirements of Color and printing technology individually adjusted, with the high Resilience (rubbery and tear resistant) must be preserved. Depending on the solvent content is more Contain softener. The proportion of silicone oils is through Tests determined and the silicone can be from 0 to 50 softeners contain.

Of the Pressure pad according to the invention can in particular for pad printing prototype construction, d. h., for the rapid one-off production for test prints because they are made quickly and inexpensively can. In addition, in the production of the inventive Print tampons virtually no waste.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• WO 2004/113075 A1 [0005]
• - EP 1053882 A [0005]
• - DE 202007006656 U1 [0005]

Claims (15)

Printing pad for pad printing, characterized in that it consists of a pourable, soft elastic, plastically deformable silicone rubber. Printing pad according to claim 1, characterized that the silicone rubber is a kneading silicone. Printing pad according to claim 1 or 2, characterized that the silicone rubber is addition-crosslinked. Printing pad according to claim 1 or 2, characterized that the silicone rubber is condensation crosslinked. A printing pad according to any one of claims 1 to 4, characterized in that it has a Shore A hardness in the range from 3 to 30. Printing pad according to claim 5, characterized that it has a Shore A hardness in the range of 6 to 8. Printing pad according to one of the preceding claims, characterized in that the silicone rubber is a 1-component silicone rubber system is. A printing pad according to any one of claims 1 to 6, characterized in that the silicone rubber is a 2-component silicone rubber system. Printing pad according to one of the preceding claims, characterized in that it is flowable in a mold is. Printing pad according to one of the preceding claims, characterized in that it has a smooth surface having. Printing pad according to one of claims 1 to 9, characterized in that it has a matted surface having. Printing pad according to one of the preceding claims, characterized in that it has a high elasticity. Printing pad according to one of the preceding claims, characterized in that it can be produced largely without waste is. Printing pad according to one of the preceding claims, characterized in that it has a high resilience having. Printing pad according to one of the preceding claims, characterized in that it contains plasticizer.