Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/025—Duplicating or marking methods; Sheet materials for use therein by transferring ink from the master sheet
  • B41M5/035—Duplicating or marking methods; Sheet materials for use therein by transferring ink from the master sheet by sublimation or volatilisation of pre-printed design, e.g. sublistatic
  • B41M5/0355—Duplicating or marking methods; Sheet materials for use therein by transferring ink from the master sheet by sublimation or volatilisation of pre-printed design, e.g. sublistatic characterised by the macromolecular coating or impregnation used to obtain dye receptive properties

Definitions

• the image or pattern to be printed is first printed on a subcarrier, in particular made of paper, using sublimable disperse dyes. Then it is placed on the plastic-coated surface with the printed side, after which the disperse dyes are transferred from the auxiliary carrier into the plastic lacquer by heating, if appropriate under low pressure.
• FR-A-2 230 794 and DE-A-2 424 949 also describe a method for printing heat-resistant sheets, such as metal sheets or ceramic tiles, according to the transfer printing method, in which the substrate is coated with an epoxy resin.
• the substrate is coated in a transfer printing process with a hardened unsaturated polyester resin.
• the substrate to be printed is coated with a crosslinked thermoset, such as a radiation-hardened unsaturated polyester resin, and those with relatively high molecular weights between 340 and 1000 are used as sublimable emulsion paints .
• This has the advantage that even with longer and relatively the printed images remain stable and show practically no migration.
• this process it is possible to obtain a sufficient transfer of the dyes during transfer printing using very short transfer printing times, such as in the band coating process.
• scratch resistance and surface hardness are of particular importance. It is known that glass powder, aluminum oxide, silicon carbide or other hard inorganic powders can improve the abrasion resistance of paint coatings. The scratch resistance and surface hardness are only slightly improved. This may be due to the sedimentation behavior of such inorganic powders.
• the object on which the invention is based was to improve the scratch resistance and surface hardness of a coated object by means of a special coating which is suitable for printing with sublimable dispersion dyes. Surprisingly, this object is achieved with the present invention.
• the lacquer coating according to the invention on the surface of a printable object for printing with sublimable disperse dyes made from a hardened thermoplastic or thermosetting lacquer binder and filler distributed therein and, if appropriate, customary lacquer additives is characterized in that it contains 10 to 100 parts by weight per 100 parts by weight of dry substance of the binder of irregularly shaped glass flakes , of which at least 90% by weight is the largest dimension solution of maximum 0.5 mm and a smallest dimension of at least 0.05 mm and a thickness of 0.5 to 20 ⁇ m.
• Such paint coatings result in an amazing increase in surface hardness and scratch resistance. If the lacquer has a Mohs hardness of 0 without the addition of glass flakes, the hardness is increased to 2 to 3 by the addition of glass flakes according to the invention, which already comes close to ceramic tiles.
• the lacquer coating according to the invention thus makes it possible for the first time to obtain utility tiles with an acceptable scratch resistance and surface hardness, which can be printed or colored with sublimable disperse dyes, for example using the transfer printing process.
• the test according to DIN EN154 for the determination of the resistance to surface wear of glazed tiles and plates resulted in a classification in group 2 with the lacquer coating according to the invention, which enables the use of such coated tiles in wet cells or for ceramic wall coverings.
• the lacquer coatings modified with glass flakes for sublimable dispersion dyes have excellent color absorption, the disperse dyes being distributed over the entire height of the lacquer coating and not only accumulating in the surface area of the lacquer coating . This was confirmed by abrasion tests, in which a substantial part of the paint coating was rubbed off, but nevertheless a strong amount of color was present in the rest of the paint coating.
• the uniform distribution of the disperse dyes over the height of the lacquer coating results in the brilliance of the printed image or the coloring, which is customary for such dispersion dyes, and also the advantage that the printed image remains unharmed even in the event of partial abrasion of the surface coating.
• the excellent dye absorption and print quality of the lacquer coatings according to the invention can be obtained even if a thixotropic agent, such as colloidal silica, bentones or castor oils, is incorporated into the coating. This is particularly surprising in view of the fact that in the case of glass powder, the use of thixotropic agents leads to a severe deterioration in printability.
• a thixotropic agent such as colloidal silica, bentones or castor oils
• the perceptible effect of the lacquer coatings according to the invention is difficult or impossible to explain.
• the glass flakes may have increased absorbency due to their ability to be stacked or due to pores or cracks, which means that the paint binder penetrates the entire filler and also allows the dyes to penetrate into the lowest areas of the coating.
• Glass flakes with the dimensions mentioned are obtained by crushing, such as hammer milling, extremely thin glass plates with the indicated thicknesses.
• the crushing process allows particles in the dimensional ranges indicated above and with irregular and jagged, i.e. H. get rounded contours.
• glass flakes in which at least 90% by weight have a maximum dimension of at most 0.25 mm.
• the thickness thereof is preferably in the range from 1 to 10, in particular in the range from 1 to 6 ⁇ m.
• the preferred amount of glass flakes in the lacquer coating is 20 to 60, especially 25 to 45 parts by weight.
• Suitable binders are the thermoplastic or thermosetting lacquer binders known in the transfer printing process. For various reasons, such as the migration resistance of the disperse dyes in the coating, thermosetting paint binders are preferred.
• thermoplastics to be used as binders are, for example, polyacrylonitrile, polyesters, polyurethanes, cellulose derivatives, polyamides, polyacrylates and others.
• crosslinked thermosets such as phenoplasts, aminoplasts, polyesters, polyphenylene sulfide resins, silicone resins, acrylate resins, alkyd resins, polyethylene sulfide resins, unsaturated polyester resins, epoxy resins and polyurethanes, are particularly preferred as binders.
• Appropriate binders are silicone resins and radiation-hardened unsaturated acrylate resins or polyester resins.
• Particularly favorable binders in the present coatings are aliphatic crosslinked hydroxyl-containing aliphatic, saturated polyesters. These are particularly suitable for printing on mineral and metallic substrates, since they have increased adhesive strength on them.
• these preferably contain 2 to 12% by weight of hydroxyl groups, 40 to 60% of which are crosslinked by a crosslinking agent, such as an aliphatic polyisocyanate or an aliphatic polyalcohol.
• these polyesters preferably contain 7 to 9% by weight of hydroxyl groups, 45 to 55% of the hydroxyl groups being crosslinked.
• the crosslinking is expediently carried out using a diisocyanate, especially hexamethylene diisocyanate.
• polyesters As binders, it is essential that both the polyester and the crosslinking components are aliphatic in nature.
• polyesters When talking about aliphatic polyesters, so can these are straight-chain or branched-chain, with branched-chain ones being preferred.
• the polyesters may also contain other organic groups, such as ether groups, in addition to the ester groups.
• the molecular weights of the polyesters used according to the invention are preferably in the range from 700 to 5000 in the uncrosslinked state. They are formed by known reaction of di- or tricarboxylic acids with excess di- or polyalcohols, so that they carry hydroxyl groups at the chain ends.
• the dicarboxylic acid that can be used for this is, for example, adipic acid.
• the diols and polyols which can be used in the production of the uncrosslinked polyesters are, for example, neopentyl glycol, ethylene glycol, propane-1,2-diol, 1,4-bis (hydroxymethyl) cyclohexane, glycerol, trimethylol propane and pentaerythritol.
• a part of the free hydroxyl groups of the polyester can be crosslinked with different polyfunctional aliphatic compounds, especially with aliphatic polyisocyanates or aliphatic polyalcohols. This is understood to mean isocyanates and alcohols with at least two isocyanate or hydroxyl groups. Crosslinking with polyisocyanates creates urethane groups, crosslinking with polyalcohols creates ether groups. Crosslinking can also be carried out with both types of compounds in order to obtain mixed urethane-ether crosslinks.
• the coatings according to the invention can be applied both as wet lacquers and as powder lacquers. If a wet lacquer, ie a solvent-based lacquer binder, is used, it is expedient, together with the glass flakes, to use a thixotropic agent, such as colloidal silica, bentone or castor oils, preferably in an amount of 0.3 to 5% by weight, based on the dry weight the coating. Powder coatings have the advantage that they give extremely high adhesion to mineral substrates and even to a ceramic glaze.
• the coatings according to the invention surprisingly have a high UV stability, which is significantly higher than the corresponding paint coatings without glass flake storage.
• the lacquer coatings according to the invention can be used for printing with any sublimable disperse dyes, advantageously with those which have a molecular weight between 340 and 1000, preferably between 400 and 1000, since they have a lower tendency to migrate and are generally lightfast.
• Preferred groups of disperse dyes for printing on lacquer coatings according to the invention are anthraquinone, monoazo and azomethine dyes, but the applicability is not limited to these groups of dyes.
• Anthraquinone, monoazo and azomethine dyes are preferred, the molecules of which are heavily occupied with amino, alkoxy, oxalkyl, nitro, halogen and cyano groups.
• These dye groups are defined in the Color Index, Volume 1, pages 1655 to 1742. In this regard, reference is made to pages 9 to 11 of EP-A-0 014 901.
• the sublimable disperse dyes can either be transferred to the lacquer coatings according to the invention in a transfer printing process from an auxiliary carrier or printed directly on. In both cases, however, it is essential that the dyes go into the lacquer coating due to the application of heat and migrate into the depth of the binder layer, which results in the high brilliance of such printed images.
• the invention also relates to coating compositions for the production of the paint coatings defined above for printing with sublimable disperse dyes.
• These coating compositions consist of a thermoplastic or preferably thermosetting paint binder, if appropriate at least one organic solvent for the paint binder, 10 to 100 parts by weight, based on the weight of the dry substance of the paint binder, of irregularly shaped glass flakes, of which at least 90% by weight have a largest dimension of at most 0.5 mm and a smallest dimension of at least 0 , 05 mm and a thickness of 0.5 to 20 ⁇ m, as well as, where appropriate, conventional paint additives, such as thixotropic agents.
• the coating compositions usually consist only of mixtures of the binder in powder form and the glass flakes.
• This method consists in providing the object with a lacquer coating which consists of a hardened thermoplastic or thermosetting lacquer binder and glass flakes distributed therein in the proportions given above and with the dimensions given above and, if appropriate, conventional lacquer additives, then the lacquer coating, directly or in Transfer printing process, printed with sublimable disperse dyes and allowing them to penetrate the paint coating by heating.
• Preferred temperatures for the heating are in the range of 210 to 260 ° C, the heating times can be in the range of seconds to minutes.
• the sublimable disperse dyes are sublimed out of the printing on the auxiliary carrier and simultaneously introduced into the coating.
• printing and subsequent heating are carried out in order to allow the disperse dyes on the coating to penetrate the coating.
• thermoplastic binders If the description refers to hardened thermoplastic binders, this means that the thermoplastic softened in the heat is solidified by cooling. In the case of thermosets, the term curing means crosslinking, so that the binder no longer softens when heated.
• the diameter of the irregularly shaped flakes perpendicular to the thickness direction i.e. H. in top view of the flakes.
• the largest dimension could also be referred to as the length of the flakes and the smallest dimension as the width of the flakes.
• the flakes are therefore at most 0.5 mm long and at least 0.05 mm wide.
• a wet paint was produced in the following way: 20 parts by weight of glass flakes with a thickness of approximately 3 ⁇ m, of which 98% by weight had a largest dimension of less than 0.25 mm and a smallest dimension of more than 0.1 mm, and 1.0 part by weight of colloidal silica (Aerosil 380) and 40.0 parts by weight of butyl acetate were thoroughly stirred together.
• 20 parts by weight of diisocyanate (Desmodur N) in 75% solution in xylene / methoxypropylacetate and 100 parts by weight of hydroxyl-containing saturated polyester paint as 65% solution in methoxypropylacetate were added and stirred vigorously.
• the wet paint thus produced was used to coat glazed ceramic tiles with an automatic spray gun, after which the coating was baked at 180 ° C. for 10 minutes.
• Table I shows the properties obtained for the two coated tiles compared: Table I with glass flakes without glass flakes Mohs hardness 2 to 3 0 Color recording 220 degrees / 3 ⁇ Good Good Color absorption of the lower lacquer layer Good Good UV resistance xenon test wool scale 7 1000 h 650 h
• a powder coating was prepared from 100 parts by weight of a commercially available powder coating hardened with TGIC and 40 parts by weight of the glass flakes specified in Example 1. The powder coating was applied in the customary manner to glazed ceramic tiles and baked in the infrared channel at 200 ° C. for 5 minutes.

Landscapes

• Paints Or Removers (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Laminated Bodies (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (3)

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ID=6358741

Family Applications (1)

Country Status (3)

Cited By (6)

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• 1988
  • 1988-07-15 DE DE3824012A patent/DE3824012A1/de not_active Withdrawn
  • 1988-12-03 AT AT88120218T patent/ATE86924T1/de not_active IP Right Cessation
  • 1988-12-03 DE DE8888120218T patent/DE3879482D1/de not_active Expired - Fee Related
  • 1988-12-03 EP EP88120218A patent/EP0350534B1/fr not_active Expired - Lifetime

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