Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B44—DECORATIVE ARTS
  • B44C—PRODUCING DECORATIVE EFFECTS; MOSAICS; TARSIA WORK; PAPERHANGING
  • B44C1/00—Processes, not specifically provided for elsewhere, for producing decorative surface effects
  • B44C1/16—Processes, not specifically provided for elsewhere, for producing decorative surface effects for applying transfer pictures or the like
  • B44C1/165—Processes, not specifically provided for elsewhere, for producing decorative surface effects for applying transfer pictures or the like for decalcomanias; sheet material therefor
  • B44C1/17—Dry transfer
• • 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
  • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
  • B41M5/382—Contact thermal transfer or sublimation processes
  • B41M5/38242—Contact thermal transfer or sublimation processes characterised by the use of different kinds of energy to effect transfer, e.g. heat and light
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B44—DECORATIVE ARTS
  • B44C—PRODUCING DECORATIVE EFFECTS; MOSAICS; TARSIA WORK; PAPERHANGING
  • B44C1/00—Processes, not specifically provided for elsewhere, for producing decorative surface effects
  • B44C1/16—Processes, not specifically provided for elsewhere, for producing decorative surface effects for applying transfer pictures or the like
  • B44C1/165—Processes, not specifically provided for elsewhere, for producing decorative surface effects for applying transfer pictures or the like for decalcomanias; sheet material therefor
  • B44C1/17—Dry transfer
  • B44C1/1712—Decalcomanias applied under heat and pressure, e.g. provided with a heat activable adhesive
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M3/00—Printing processes to produce particular kinds of printed work, e.g. patterns
  • B41M3/12—Transfer pictures or the like, e.g. decalcomanias
• • 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
  • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
  • B41M5/382—Contact thermal transfer or sublimation processes
  • B41M5/38207—Contact thermal transfer or sublimation processes characterised by aspects not provided for in groups B41M5/385 - B41M5/395
  • B41M5/38214—Structural details, e.g. multilayer systems
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B44—DECORATIVE ARTS
  • B44C—PRODUCING DECORATIVE EFFECTS; MOSAICS; TARSIA WORK; PAPERHANGING
  • B44C1/00—Processes, not specifically provided for elsewhere, for producing decorative surface effects
  • B44C1/16—Processes, not specifically provided for elsewhere, for producing decorative surface effects for applying transfer pictures or the like
  • B44C1/165—Processes, not specifically provided for elsewhere, for producing decorative surface effects for applying transfer pictures or the like for decalcomanias; sheet material therefor
  • B44C1/17—Dry transfer
  • B44C1/1712—Decalcomanias applied under heat and pressure, e.g. provided with a heat activable adhesive
  • B44C1/1729—Hot stamping techniques
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M2205/00—Printing methods or features related to printing methods; Location or type of the layers
  • B41M2205/06—Printing methods or features related to printing methods; Location or type of the layers relating to melt (thermal) mass transfer
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M2205/00—Printing methods or features related to printing methods; Location or type of the layers
  • B41M2205/10—Post-imaging transfer of imaged layer; transfer of the whole imaged layer
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M2205/00—Printing methods or features related to printing methods; Location or type of the layers
  • B41M2205/30—Thermal donors, e.g. thermal ribbons
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M2205/00—Printing methods or features related to printing methods; Location or type of the layers
  • B41M2205/40—Cover layers; Layers separated from substrate by imaging layer; Protective layers; Layers applied before imaging

Definitions

• the present invention relates to thermal transfer foils and their use for the dry coating of surfaces.
• the invention also relates to the production of such thermal transfer foils and a method for coating or varnishing surfaces of objects using the thermal transfer foils according to the invention.
• the surfaces of objects are usually coated using the wet paint process, i. H. a liquid paint is applied to the surface to be coated and then dried, creating a layer of paint on the surface.
• a liquid paint is applied to the surface to be coated and then dried, creating a layer of paint on the surface.
• painting usually takes place in painting lines, with longer drying lines regularly being necessary for drying, during which the paint is dried and cured with a comparatively high expenditure of energy. Such methods are therefore time-, energy- and personnel-intensive.
• the coating devices of the painting lines have to be cleaned, which leads to downtimes.
• the waste generated when cleaning the machines must be disposed of as hazardous waste.
• Some two-component paints have a limited pot life and any unused residue must also be disposed of as hazardous waste.
• thermo transfer foils These films comprise a carrier film on which one or more polymer layers and optionally an adhesive layer are arranged.
• the at least one polymer layer is transferred from the carrier film to the surface to be coated by means of pressure and/or heat.
• the at least one polymer layer forms a lacquer layer on the surface to be coated without organic solvents having to be used in the coating process.
• the EP 573676 describes a method for applying a lacquer with colored decoration to a substrate, for example on wood or plastic surfaces, in which a film is used which has a decorative layer applied to a carrier with release properties and a partially crosslinked lacquer layer applied to the decorative layer.
• the film is applied to the surface to be coated with the paint layer and transferred to the surface with the decorative layer by pressure and elevated temperature, with the paint layer curing at the same time.
• Thermally curable lacquers are used as lacquers. Due to the high temperatures required in the paint curing process, the selection of substrates is severely restricted.
• thermal transfer foils which have a decorative layer arranged on a carrier layer and a heat-activatable adhesive layer arranged on the decorative layer, the carrier layer having a metallic functional layer lying directly on the decorative layer, which facilitates the detachment of the decorative layer from the carrier layer and thus improves the transfer of the Decorative layer should ensure on the substrate.
• the metallization limits the decorative layer.
• the EP1970215 in turn describes thermal transfer films suitable for the coating of surfaces, which have a base lacquer layer connected to a carrier film and also functioning as a separating layer, a colored decorative layer and a transfer layer with an adhesive effect, the layers being based on aqueous coating systems which contain heat-drying aqueous polymer dispersions as binders.
• the surface hardness and abrasion resistance of the coatings obtained are often unsatisfactory. Highly abrasion-resistant coatings cannot be obtained with the thermal transfer films described there.
• EP-A-0 210 620 describes a method for producing a film having a textured lacquer layer.
• the EP2078618 describes thermal transfer films which have at least one topcoat layer arranged on a carrier film and a thermally activatable adhesive layer, the topcoat layer preferably being based on an aqueous coating composition which contains a dispersed polyurethane which is curable by UV radiation. It is true that the thermal transfer foils described there lead to improved surface hardness in comparison with thermal transfer foils whose lacquer layers are based on heat-drying aqueous polymer dispersions. However, this is not satisfactory for some applications. In addition, the use of aqueous coating agents is associated with an increased drying effort in the production of the thermal transfer foils. The coatings described there are not always satisfactory in terms of abrasion resistance and surface properties. Highly abrasion-resistant coatings cannot be obtained with the thermal transfer films described there.
• thermal transfer films which have at least one coating layer arranged on the carrier film and which is based on a non-aqueous, radiation-curable, liquid composition which contains at least 60% by weight, in particular at least 70% by weight, based on the total weight the composition containing crosslinkable components selected from organic oligomers containing ethylenically unsaturated double bonds and mixtures of these oligomers with monomers containing at least one ethylenically unsaturated double bond and having a heat-sealable polymeric adhesive layer (4) containing at least one UV contains radiation-curable component and is based on at least two aqueous polymer dispersions, at least one polymer dispersion containing a UV-curable polymer in dispersed form and at least one further polymer dispersion containing a self-crosslinking polymer in dispe contains rged form, are particularly suitable for coating surfaces.
• thermal transfer foils leads to particularly resistant surfaces that adhere particularly well to the coated substrates.
• non-aqueous, radiation-curable coating compositions with a high proportion of crosslinkable components allows the targeted adaptation of the thermal transfer film for different substrates, namely for both hard and highly elastic substrates.
• thermal transfer foils with lacquer layers based on thermally curable coating agents the temperature load on the material to be coated during the transfer of the lacquer layer(s) to the surface to be coated is comparatively low, since final curing can easily be carried out by irradiating the coated surface with UV radiation and no subsequent tempering is necessary.
• the radiation-curable, liquid compositions used to produce the lacquer layer contain at least 60% by weight, in particular at least 70% by weight, e.g. B. 60 to 99% by weight, in particular 70 to 95% by weight, based on the total weight of the composition, of curable components which have ethylenically unsaturated double bonds.
• the components are preferably selected such that the composition contains 1.5 to 8 mol, in particular 2.0 to 7 mol and especially 2.5 to 6.5 mol of ethylenically unsaturated double bonds per kg of the coating composition.
• the ethylenically unsaturated double bonds of the curable components of the liquid, radiation-curable composition which forms the coating layer are preferably in the form of acrylic groups, methacrylic groups, allyl groups, fumaric acid groups, maleic acid groups and/or maleic anhydride groups, in particular at least 90% or 100%, based on the total amount of the ethylenically unsaturated double bonds contained in the composition, in the form of acrylic or methacrylic groups and especially in the form of acrylic groups.
• the acrylic and methacrylic groups may be in the form of (meth)acrylamide or (meth)acrylate groups, with the latter being preferred.
• at least 90% or 100% based on the total amount of the ethylenically unsaturated double bonds present in the composition, of the curable components of the radiation-curable composition which forms the lacquer layer have acrylate groups.
• the liquid, radiation-curable compositions which are used to produce the coating layer contain at least one oligomer which has ethylenically unsaturated double bonds.
• the oligomers preferably have an average functionality in the range from 1.5 to 10, in particular in the range from 2 to 8.5, i. H. the number of ethylenically unsaturated double bonds per molecule is on average in the range from 1.5 to 10 and in particular in the range from 2 to 8.5.
• Mixtures of different oligomers with different functionality are also suitable, the average functionality preferably being in the range from 1.5 to 10, in particular in the range from 2 to 8.5.
• the oligomers typically have a linear or branched basic structure which carries on average more than one ethylenically unsaturated double bond, preferably in the form of the aforementioned acrylic groups, methacrylic groups, allyl groups, fumaric acid groups, maleic acid groups and/or maleic anhydride groups, in particular in the form of acrylic or methacrylic groups, where the ethylenically unsaturated double bonds can be bonded to the basic structure via a linker or are part of the basic structure.
• Suitable oligomers are primarily oligomers from the group of polyethers, polyesters, polyurethanes and epoxide-based oligomers. Preference is given to oligomers which have essentially no aromatic structural units and mixtures of oligomers with aromatic groups and oligomers without aromatic groups.
• the oligomers are selected from polyether (meth)acrylates, i. H. Polyethers with acrylic or methacrylic groups, polyester (meth)acrylates, d. H. Polyesters with acrylic or methacrylic groups, epoxy (meth)acrylates, d. H. Reaction products of polyepoxides with hydroxyl-functionalized acrylic or methacrylic compounds, urethane (meth)acrylates, i. H. Oligomers which have a (poly)urethane skeleton and acrylic or methacrylic groups, for example reaction products of polyisocyanates with hydroxyl-functionalized acrylic or methacrylic compounds, and unsaturated polyester resins, d. H.
• Polyesters which have several ethylenically unsaturated double bonds, preferably present in the polymer backbone, e.g. B. condensation products of maleic acid or fumaric acid with aliphatic diols or polyols, and mixtures thereof.
• the oligomers typically have a molecular weight (number average) of at least 400 g/mol, in particular at least 500 g/mol, e.g. B. in the range of 400 to 4000 g / mol and in particular in the range of 500 to 2000 g / mol.
• the monomers typically have molecular weights below 400 g/mol, e.g. B. in the range of 100 to ⁇ 400 g / mol.
• Suitable polyether (meth)acrylates are primarily aliphatic polyethers, especially poly(C 2 -C 4 )-alkylene ethers, which have on average 2 to 4 acrylate or methacrylate groups. Examples of these are the Laromer® grades PO33F , LR8863, GPTA, LR8967, LR8962, LR9007 from BASF SE, some of which are mixtures with monomers.
• Suitable polyester (meth)acrylates are primarily aliphatic polyesters which have an average of 2 to 6 acrylate or methacrylate groups. Examples of these are the Laromer® grades PE55F , PE56F, PE46T, LR9004, PE9024, PE9045, PE44F, LR8800, LR8907, LR9032, PE9074, PE9079, PE9084 from BASF SE, some of which are mixtures with monomers.
• Suitable polyurethane acrylates are primarily compounds containing urethane groups which have an average of 2 to 10, in particular 2 to 8.5, acrylate or methacrylate groups and which are preferably obtainable by reacting aromatic or aliphatic di- or oligoisocyanates with hydroxyalkyl acrylates or hydroxyalkyl methacrylates. Examples of these are the Laromer® types UA19T, UA9028, UA9030, LR8987, UA9029, UA9033, UA9047, UA9048, UA9050, UA9072, UA9065 and UA9073 from BASF SE, some of which are mixtures with monomers.
• the radiation-curable, liquid composition which forms the lacquer layer comprises at least one oligomer selected from urethane acrylates and polyester acrylates and mixtures thereof, and optionally one or more monomers.
• the radiation-curable, liquid composition which forms the lacquer layer comprises at least one urethane acrylate and optionally one or more monomers.
• the radiation-curable, liquid composition which forms the lacquer layer comprises at least one polyester acrylate and optionally one or more monomers.
• the radiation-curable, liquid composition that forms the lacquer layer comprises at least one urethane acrylate and at least one polyester acrylate and optionally one or more monomers.
• the radiation-curable, liquid composition which forms the lacquer layer comprises at least one aliphatic urethane acrylate and at least one aromatic urethane acrylate or at least two different aliphatic urethane acrylates and optionally one or more monomers.
• the radiation-curable, liquid composition which forms the lacquer layer comprises at least one aliphatic urethane acrylate, at least one aromatic urethane acrylate and at least one polyester acrylate and optionally one or more monomers.
• the crosslinkable components of the radiation-curable, liquid composition used to produce the coating layer can contain one or more monomers, which are also referred to as reactive diluents.
• the monomers typically have molecular weights below 400 g/mol, e.g. B. in the range of 100 to ⁇ 400 g / mol.
• Suitable monomers generally have 1 to 6, in particular 2 to 4, ethylenically unsaturated double bonds per molecule.
• the ethylenically unsaturated double bonds are preferably present in the form of the aforementioned acrylic groups, methacrylic groups, allyl groups, fumaric acid groups, maleic acid groups and/or maleic anhydride groups, in particular in the form of acrylic or methacrylic groups and specifically as acrylate groups.
• Preferred monomers are selected from esters of acrylic acid with 1- to 6-hydric, in particular 2- to 4-hydric, aliphatic or cycloaliphatic alcohols, which preferably have 2 to 20 carbon atoms, such as monoesters of acrylic acid with C 1 -C 20 - alkanols, benzyl alcohol, furfuryl alcohol, tetrahydrofurfuryl alcohol, (5-ethyl-1,3-dioxan-5-yl)methanol, phenoxyethanol, 1,4-butanediol or 4-tert-butylcyclohexanol; diesters of acrylic acid with ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, dipropylene glycol or tripropylene glycol; Triesters of acrylic acid with trimethylolpropane or pentaeryth
• Suitable monomers are, above all, trimethylolpropane diacrylate, trimethylolpropane triacrylate, ethylene glycol diacrylate, butanediol diacrylate, hexanediol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, phenoxyethyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, 4-t-butylcyclohexyl acrylate, 4-hydroxybutyl acrylate and trimethylolformal monoacrylate (acrylic acid-(5-ethyl-1,3- dioxan-5-yl)methyl ester).
• the radiation-curable liquid composition forming the lacquer layer comprises at least one oligomer, e.g. B. 1, 2 or 3 oligomers, in particular at least one, z. 1, 2 or 3 of the oligomers mentioned as preferred and at least one monomer, e.g. B. 1, 2 or 3 monomers, in particular at least one, z. B. 1, 2 or 3, of the monomers mentioned as preferred.
• the oligomer preferably forms the major part of the curable components of the composition, e.g. H. the oligomer(s) make up at least 50% by weight, in particular at least 60% by weight, based on the total amount of oligomer and monomer.
• the weight ratio of oligomer to monomer is in particular in the range from 1:1 to 20:1 and especially in the range from 3:2 to 10:1.
• the radiation-curable, liquid composition which is used to produce the lacquer layer, comprises exclusively or almost exclusively, i. H. at least 90% by weight, in particular at least 95% by weight, especially at least 99% by weight, based on the total amount of radiation-curable components of the composition, of one or more oligomers, e.g. B. 2, 3 or 4 oligomers, in particular 2, 3 or 4 of the oligomers mentioned as preferred.
• the proportion of the monomers is then accordingly at most 10% by weight, in particular at most 5% by weight, especially at most 1% by weight or at 0% by weight, based on the total amount of radiation-curable components of the composition.
• Such compositions preferably contain at least one polyester acrylate and/or polyurethane acrylate and at least one polyether acrylate.
• the radiation-curable, liquid composition used to produce the coating layer generally contains one or more other components, such as photoinitiators, inert fillers, abrasives, flow control agents, coloring components, in particular color pigments, organic solvents and the like. According to the invention, these components make up no more than 40% by weight, in particular no more than 30% by weight, e.g. B. 1 to 40 wt .-%, in particular 5 to 30 wt .-%, based on the total weight of radiation curable liquid composition.
• the radiation-curable, liquid composition preferably contains no or no more than 10% by weight, based on its total weight, of non-polymerizable volatile components.
• volatile constituents are understood to be substances which have a boiling point or an evaporation point below 250° C. at atmospheric pressure, for example organic solvents.
• the radiation-curable, liquid composition used to produce the coating layer preferably contains at least one photoinitiator.
• Photoinitiators are substances which, when exposed to UV radiation, i. H. Light with a wavelength below 420 nm, in particular below 400 nm, decomposes with the formation of free radicals and thus triggers a polymerization of the ethylenically unsaturated double bonds.
• the radiation-curable, liquid composition preferably contains at least one photoinitiator which has at least one absorption band which has a maximum in the range from 220 to 420 nm, in particular in the range from 240 to 400 nm and which is coupled with the initiation of the decomposition process.
• the nonaqueous, liquid, radiation-curable composition preferably contains at least one photoinitiator which has at least one absorption band with a maximum in the range from 220 to 420 nm, in particular a maximum in the range from 240 to 400 nm.
• Preferred photoinitiators are primarily selected from the groups of alpha-hydroxyalkylphenones, alpha-dialkoxyacetophenones, phenylglyoxalic acid esters, benzophenones, benzoins and acylphosphine oxides.
• the liquid, radiation-curable composition preferably contains at least one photoinitiator which has an absorption band with a maximum ⁇ max in the range from 230 to 340 nm.
• the non-aqueous, liquid, radiation-curable composition used to produce the lacquer layer preferably contains at least two different photoinitiators in which the maxima of the absorption bands differ, preferably by at least 40 nm and in particular by at least 60 nm.
• such a non-aqueous, liquid, radiation-curable composition contains a mixture of at least two different photoinitiators, with at least one photoinitiator (hereinafter photoinitiator I) having an absorption band with a maximum ⁇ max in the range from 340 to 420 nm and especially in the range from 360 to 420 nm and wherein at least one further photoinitiator (hereinafter photoinitiator II) has an absorption band with a maximum ⁇ max in the range from 220 to 340 and especially in the range from 230 to 320 nm.
• the weight ratio of the total amount of photoinitiators I to the total amount of photoinitiators II is preferably in the range from 2:1 to 1:20.
• Preferred photoinitiators which have an absorption band with a maximum ⁇ max in the range from 220 to 340 and especially in the range from 230 to 320 nm are the aforementioned alpha-hydroxyalkylphenones, alpha-dialkoxyacetophenones, phenylglyoxalic acid esters, benzophenones and benzoins.
• Preferred photoinitiators which have an absorption band with a maximum ⁇ max in the range from 340 to 420 nm and especially in the range from 360 to 420 nm are the aforementioned acylphosphine oxides.
• the photoinitiators comprise at least one alpha-hydroxyalkylphenone or alpha-dialkoxyacetophenone and at least one acylphosphine oxide and optionally a phenylglyoxylic acid ester and optionally a benzophenone.
• the weight ratio of acylphosphine oxide to alpha-hydroxyalkylphenone or alpha-dialkoxyacetophenone is preferably in the range from 2:1 to 1:20.
• the total amount of photoinitiators is typically in the range from 0.5 to 10% by weight, in particular 1 to 5% by weight, based on the total weight of the non-aqueous liquid radiation-curable composition.
• nonaqueous, liquid, radiation-curable compositions according to the invention can also be formulated without an initiator, particularly when the subsequent curing takes place by means of electron beams.
• the non-aqueous, liquid, radiation-curable compositions can contain one or more fillers, i. H. solid particulate components which are insoluble in the oligomers and the monomers.
• these include, above all, aluminum oxides, for example in the form of corundum, and silicon dioxide, such as pyrogenic silica and synthetic, amorphous silica, e.g. B. Precipitated silica.
• the mean particle sizes of the fillers can vary over a wide range and are typically in the range from 1 nm to 100 ⁇ m, in particular in the range from 10 nm to 50 ⁇ m, depending on the type of filler.
• the total amount of filler will generally not exceed 40%, especially 30% by weight based on the total weight of the composition and, if included, will typically range from 1 to 39.5% by weight and especially in the range of 2 to 29% by weight.
• the non-aqueous, liquid, radiation-curable compositions preferably contain one or more abrasives.
• Abrasives are fillers that give the paint layer increased surface hardness and improved abrasion resistance. These include above all corundum, quartz powder, glass powder, e.g. B. glass flakes and nanoscale silica.
• non-aqueous, liquid, radiation-curable compositions can contain one or more other additives, for example flow control agents, e.g. B. siloxane-containing polymers such as polyether siloxane copolymers, and UV stabilizers, z. B. sterically hindered amines (so-called HALS stabilizers).
• flow control agents e.g. B. siloxane-containing polymers such as polyether siloxane copolymers, and UV stabilizers, z. B. sterically hindered amines (so-called HALS stabilizers).
• Tables A1, A2 and A3 Typical compositions of the non-aqueous, liquid, radiation-curable compositions which are used to produce the lacquer layer are given in Tables A1, A2 and A3 below.
• Table A1 raw material Amount [% by weight] 1) Urethane acrylate, functionality about 2.0 to 6.0 15 - 30 Polyester acrylate, functionality 3.0 to 3.5 5 - 15 Trimethylolpropane formal monoacrylate 5 - 15 trimethylolpropane triacrylate 10 - 20 dipropylene glycol diacrylate 10 - 20 Aliphatic urethane acrylate, functionality 1.5 to 3.5 3 - 15 aluminum oxide (corundum) 20 - 30 Fumed silica 0.1 - 5 phenyl glyoxylate 0.5 - 3 acylphosphine oxide 0.2 - 1 alpha-hydroxyalkylphenone 0.5 - 3 1) based on the total weight of the composition raw material Amount [% by weight] 1) Urethane acrylate, functionality
• polyethersiloxane 0.2 - 5 phenyl glyoxylate 0.5 - 3 acylphosphine oxide 0.1 - 0.5 alpha-hydroxyalkylphenone 0.5 - 3 benzophenone 0.5 - 3 1) based on the total weight of the composition raw material Amount [% by weight] 1) Mixture of two or three polyester acrylates, average functionality 2.0 to 4.0 40 - 65 Trimethylolpropane formal monoacrylate 5 - 20 Acrylate of an ethoxylated phenol 5 - 20 dipropylene glycol diacrylate 5 - 20 Fumed silica 1 - 10 leveling agent (e.g.
• polyethersiloxane 0.2 - 5 phenyl glyoxylate 0.5 - 3 acylphosphine oxide 0.1 - 1 alpha-hydroxyalkylphenone 0.5 - 3 benzophenone 0.5 - 3 1) based on the total weight of the composition
• the thermal transfer foils according to the invention can have one or more lacquer layers arranged one on top of the other, which according to the invention are based on the above-described non-aqueous, liquid, radiation-curable compositions.
• the total layer thickness of the paint layer i. H. in the case of several paint layers, the sum of all layer thicknesses is typically in the range from 10 to 120 ⁇ m, in particular in the range from 30 to 80 ⁇ m.
• the layer thickness of the lacquer layer is therefore preferably in the range from 10 to 120 ⁇ m, in particular in the range from 30 to 80 ⁇ m.
• the individual layer thicknesses are typically in the range from 10 to 100 ⁇ m, in particular in the range from 20 to 70 ⁇ m.
• the thermal transfer film according to the invention comprises exactly one lacquer layer arranged on the carrier film.
• the thermal transfer film according to the invention comprises a lacquer layer arranged on the carrier film and one or more, e.g. B. one or two further coating layers based on the non-aqueous, liquid, radiation-curable compositions described above.
• the lacquer layers can be arranged directly one on top of the other.
• a decorative layer can also be provided between two lacquer layers in order to give the object coated with the thermal transfer film a colored design.
• Decorative layers typically have layer thicknesses in the range from 0.5 to 5 ⁇ m, in particular in the range from 0.5 to 2.5 ⁇ m and especially in the range from 1 to 1.5 ⁇ m.
• the thermal transfer films according to the invention have at least one polymeric adhesive layer, in particular precisely one adhesive layer.
• the adhesive layer is either arranged directly on the lacquer layer or, in the case of several lacquer layers, directly on the uppermost lacquer layer, or a decorative layer can also be provided between the lacquer layer and the adhesive layer.
• the adhesive layer is heat-sealable, ie it is not tacky at room temperature and develops its adhesive effect only when heated.
• the adhesive layer contains at least one component that crosslinks when exposed to UV light. This component is an organic oligomer or polymer that has ethylenically unsaturated double bonds.
• the adhesive layer is based on at least two aqueous polymer dispersions, at least one polymer dispersion containing a UV-curable polymer in dispersed form and at least one further polymer dispersion containing a self-crosslinking polymer in dispersed form.
• the heat-sealable adhesive sheet of the present invention comprises at least one polymer as a main component.
• the polymer itself can be radiation-curable or it can be blended with one or more radiation-curable oligomers or polymers which have ethylenically unsaturated double bonds.
• the polymers, which form the main component of the heat-sealable adhesive layer are crosslinkable, ie they crosslink when heated or when irradiated with UV light to form covalent bonds between the polymer chains.
• the adhesive layer comprises both oligomeric and/or polymeric components that can be crosslinked by heating and components that can be crosslinked by exposure to UV radiation. This is achieved in that the adhesive layer comprises both polymers, which crosslink when heated, and oligomers or polymers, which are crosslinked through the action of UV radiation.
• the adhesive layer can also contain so-called dual-cure polymers, ie polymers which crosslink both when exposed to high-energy radiation and when heated.
• the adhesive layer contains at least one water-insoluble polymer from an aqueous polymer dispersion, which is usually used for the production of adhesive layers, and in particular from pure acrylate polymers, Styrene acrylate polymers, polyurethanes, in particular polyester urethanes and polyether urethanes, and which is self-crosslinking, and at least one radiation-curing oligomer or polymer from an aqueous polymer dispersion.
• Physically drying polymers are those polymers which, on drying, form a solid polymer film in which the polymer chains are not crosslinked.
• Self-crosslinking polymers are those polymers which, on drying, form a solid polymer film in which the polymer chains are crosslinked.
• Self-crosslinking polymers have reactive functional groups, for example hydroxyl groups, carboxyl groups, isocyanate groups, blocked isocyanate groups, ketocarbonyl groups or epoxide groups, which can react with one another or with the reactive groups of a crosslinking agent to form covalent bonds.
• the adhesive layer contains at least one water-insoluble polymer selected from polyurethanes, in particular polyester urethanes and polyether urethanes, and which is physically drying or self-crosslinking, and at least one radiation-curing oligomer or polymer.
• the adhesive layer contains at least one water-insoluble polymer selected from self-crosslinking pure acrylate polymers and self-crosslinking styrene acrylate polymers, and at least one radiation-curing oligomer or polymer.
• the adhesive layer contains at least one water-insoluble polymer selected from self-crosslinking pure acrylate polymers and self-crosslinking styrene acrylate polymers and at least one water-insoluble polymer selected from polyurethanes, in particular polyester urethanes and polyether urethanes, and which is physically drying or self-crosslinking is, and at least one radiation-curing oligomer or polymer.
• the radiation-curable oligomers and polymers of the adhesive layer are basically those oligomers and polymers which have ethylenically unsaturated double bonds. These double bonds are preferably at least 90% or 100%, based on the total amount of the ethylenically unsaturated double bonds, in the form of acrylic or methacrylic groups and especially in the form of acrylic groups.
• the acrylic and methacrylic groups may be in the form of (meth)acrylamide or (meth)acrylate groups, with the latter being preferred.
• the radiation-curable components of the adhesive layer contain acrylate groups to an extent of at least 90% or 100%, based on the total amount of the ethylenically unsaturated double bonds present in the adhesive layer.
• the radiation-curable oligomers and polymers of the adhesive layer preferably have an average functionality in the range from 2 to 20, in particular in the range from 2 to 10, i. H. the number of ethylenically unsaturated double bonds per molecule is on average in the range from 2 to 20 and in particular in the range from 2 to 10.
• the radiation-curable oligomers and polymers of the adhesive layer are selected from polyether (meth)acrylates, polyester (meth)acrylates, epoxy (meth)acrylates, urethane (meth)acrylates, for example reaction products of polyisocyanates with hydroxyl-functionalized acrylic or methacrylic compounds, and unsaturated ones polyester resins.
• the radiation-curable oligomers and polymers of the adhesive layer are selected from polyether (meth)acrylates, epoxy (meth)acrylates and urethane (meth)acrylates.
• Suitable polyurethane acrylates are primarily polymers containing urethane groups which have an average of 2 to 10, in particular 2 to 8.5, acrylate or methacrylate groups, in particular polyether urethane arylates, and which are preferably obtainable by reacting polyether urethanes containing isocyanate groups with hydroxyalkyl acrylates or hydroxyalkyl methacrylates . Examples of this are the Laromer® types LR 8949, LR 8983 and LR 9005 from BASF SE.
• the polymers which preferably form the main component of the heat-sealable adhesive layer, have a glass transition temperature Tg in the uncrosslinked state, determined by means of differential scanning calorimetry (DSC) according to ASTM D3418 in the range from -60 to 90 ° C, in particular 0 to 90°C, and/or they are partially crystalline polymers with a melting point in the range from -60 to 90°C, in particular 0 to 90°C, determined by DSC. If the adhesive composition contains several polymers, these can also have different glass transition temperatures in the uncrosslinked state.
• DSC differential scanning calorimetry
• At least part, in particular at least 30% by weight, of these polymers, based on the total amount of the polymer components of the adhesive composition, in the uncrosslinked state have a glass transition temperature Tg in the range from 0 to 90° C., in particular in the range from 20 to 90 °C.
• Adhesive compositions for producing heat-sealable polymer layers are familiar to the person skilled in the art and can be purchased commercially or produced by mixing commercially available adhesive raw materials according to known guide recipes.
• the adhesive layer (4) is based on at least two aqueous polymer dispersions, ie water-based adhesives are used to produce the adhesive layer, ie adhesives which contain the polymers and optionally oligomers in the form of aqueous polymer dispersions.
• aqueous polymer dispersions are self-crosslinking aqueous polymer dispersions, ie aqueous polymer dispersions which contain a reactive dispersed polymer and optionally a crosslinking agent which reacts with the reactive groups of the reactive polymer on drying and/or heating to form a bond.
• aqueous pure acrylate dispersions self-crosslinking aqueous styrene acrylate dispersions and self-crosslinking aqueous polyurethane dispersions, in particular aqueous polyether urethane dispersions and polyester urethane dispersions.
• Pure acrylate dispersions are understood as meaning aqueous polymer dispersions based on alkyl acrylates and alkyl methacrylates.
• Styrene acrylates are understood as meaning aqueous polymer dispersions based on styrene, alkyl acrylates and optionally alkyl methacrylates.
• Polyurethane dispersions are understood as meaning aqueous dispersions of polyurethanes, in particular polyether urethanes and polyester urethanes.
• the polymers have reactive functional groups, for example hydroxyl groups, carboxyl groups, isocyanate groups, blocked isocyanate groups, ketocarbonyl groups or epoxide groups, which can react with the reactive groups of the crosslinking agent to form covalent bonds.
• Suitable crosslinking agents are compounds with at least two reactive groups, for example hydrazide groups, amino groups, hydroxyl groups, epoxide groups, isocyanate groups.
• self-crosslinking aqueous polymer dispersions are the products available under the trade names Luhydran® A 849, Acronal® 849 S, Joncryl® 8330, Joncryl® 8383 from BASF SE and Alberdingk® AC 2742 from Alberdingk Boley GmbH.
• Suitable aqueous polymer dispersions are UV-crosslinkable polymer dispersions, ie polymer dispersions which contain a dispersed polymer which has polymerizable ethylenically unsaturated double bonds, preferably in the form of the aforementioned acrylic groups, methacrylic groups, allyl groups, fumaric acid groups, maleic acid groups and/or maleic anhydride groups, in particular in the form of acrylic - or methacryl groups are present, it being possible for the ethylenically unsaturated double bonds to be bonded to the basic structure via a linker or to be part of the basic structure.
• UV-crosslinkable aqueous polymer dispersions are aqueous dispersions of polyester acrylates, urethane acrylates and epoxy acrylates, such as those sold by BASF under the trade names Laromer® PE22WN , PE55WN, LR8949, LR8983, LR9005, UA9060, UA9095 and UA9064.
• the aqueous adhesive composition contains, in addition to the polymer of a self-crosslinking polymer dispersion, at least one UV-curable component which is generally selected from the aforementioned polymers and oligomers which have ethylenically unsaturated double bonds and which is also present in dispersed form, i. H. in the form of an aqueous polymer dispersion.
• the radiation-curable oligomers and polymers of the aqueous adhesive composition are, in particular, oligomers and polymers whose double bonds are at least 90% or 100%, based on the total amount of ethylenically unsaturated double bonds, in the form of acrylic or methacrylic groups and especially in the form of acrylic groups present.
• the acrylic and methacrylic groups may be in the form of (meth)acrylamide or (meth)acrylate groups, with the latter being preferred.
• the radiation-curable oligomers and polymers of the aqueous adhesive composition preferably have on average a functionality in the range from 2 to 20, in particular in the range from 2 to 10, ie the number of ethylenically unsaturated double bonds per molecule is on average in the range from 2 to 20 and in particular in the range from 2 to 10.
• Mixtures of different are also suitable Oligomers or polymers with different functionality, the average functionality preferably being in the range from 2 to 20, in particular in the range from 2 to 10.
• the radiation-curable oligomers and polymers of the aqueous adhesive composition are selected from polyether (meth)acrylates, polyester (meth)acrylates, epoxy (meth)acrylates, urethane (meth)acrylates, and unsaturated polyester resins.
• the radiation-curable oligomers and polymers of the aqueous adhesive composition are selected from polyether (meth)acrylates, epoxy (meth)acrylates and polyurethane (meth)acrylates.
• Suitable polyurethane acrylates are, in particular, polymers containing urethane groups which have on average 2 to 10, in particular 2 to 8.5, acrylate or methacrylate groups and which are preferably obtainable by reacting polyurethanes containing isocyanate groups with hydroxyalkyl acrylates or hydroxyalkyl methacrylates. Examples of these are the Laromer® types LR 8949, LR 8983 and LR9005 from BASF SE.
• aqueous UV-crosslinkable polymer dispersion e.g. B. an aqueous urethane acrylate dispersion and / or an aqueous epoxy acrylate dispersion
• self-crosslinking aqueous polymer dispersion e.g. B. an aqueous urethane acrylate dispersion and / or an aqueous epoxy acrylate dispersion
• the adhesive compositions used to produce the polymeric adhesive layer can contain the additives customary for this purpose, for example waxes, adhesive resins, defoamers, flow control agents, surfactants, agents for adjusting the pH value, one or more of the aforementioned fillers and UV stabilizers, e.g. B. sterically hindered amines (so-called HALS stabilizers).
• additives customary for this purpose for example waxes, adhesive resins, defoamers, flow control agents, surfactants, agents for adjusting the pH value, one or more of the aforementioned fillers and UV stabilizers, e.g. B. sterically hindered amines (so-called HALS stabilizers).
• the adhesive composition used to prepare the polymeric adhesive layer typically also contains at least one photoinitiator, typically selected from the aforementioned alpha-hydroxyalkylphenones, alpha-dialkoxyacetophenones, phenylglyoxylic esters, benzophenones, benzil derivatives, acylphosphine oxides, oxime esters, alpha-aminoalkylphenones and benzoins.
• Preferred photoinitiators are primarily selected from the groups of alpha-hydroxyalkylphenones, alpha-dialkoxyacetophenones, phenylglyoxalic acid esters, benzophenones, benzoins and acylphosphine oxides.
• the adhesive composition used to produce the polymeric adhesive layer preferably contains at least one photoinitiator which has an absorption band with a maximum ⁇ max in the range from 230 to 340 nm.
• it contains at least two different photoinitiators in which the maxima of the absorption bands differ, preferably by at least 40 nm and in particular at least 60 nm.
• the photoinitiators include at least one alpha-hydroxyalkylphenone or alpha-dialkoxyacetophenone and at least one acylphosphine oxide as well optionally a phenylglyoxylic acid ester and optionally a benzophenone.
• the weight ratio of acylphosphine oxide to alpha-hydroxyalkylphenone or alpha-dialkoxyacetophenone is preferably in the range from 2:1 to 1:20.
• the total amount of photoinitiators is typically in the range from 0.5 to 10% by weight, in particular 1 to 5% by weight % based on the total weight of the adhesive composition used to make the polymeric adhesive layer.
• Adhesive composition 1 UV curable, unpigmented
• Adhesive composition 1 30 -70 parts a self-crosslinking aqueous acrylate dispersion (50% by weight) 10-50 parts a radiation-curable polyurethane acrylate dispersion (40-50% by weight), 5-10 Parts of a hydrophobic fumed silica 5-10 Parts of a non-ionic wax dispersion 1.5-3 Parts of a blend of an alpha-hydroxyalkylphenone and benzophenone 0.5-1 Parts of an acylphosphine oxide and optionally the following components 0-20 share water 0.8-1.5 parts a mineral-based defoamer 0.4-1.2 parts a polyethersiloxane copolymer 0.5-1.0 parts a leveling agent containing fluorosurfactant 2-4 parts Butyl glycol as a film-forming agent 0.3-0.5 Parts of a polyurethane
• an organic amine 25-45 parts a self-crosslinking aqueous acrylate dispersion (50% by weight) 5-20 parts a radiation-curable aqueous polyetherurethane acrylate dispersion (40-50% by weight) 3-10 parts
• Epoxy acrylate, water-dilutable 5-25 parts color pigment e.g. As titanium dioxide or colored pigment 1-8 parts a fumed silica or an amorphous synthetic silicate or a combination of a fumed silica and an amorphous synthetic silicate 1-6 parts a non-ionic wax dispersion 2-10 parts a wax, e.g. B.
• Hydroxystyrene Acrylate Copolymer 1-3 parts a blend of an alpha-hydroxyalkylphenone and benzophenone 0.5-1 parts an acylphosphine oxide and optionally the following ingredients 0.1-5 parts plasticizers, e.g. B. triethyl citrate 0.2-1.0 parts a polyethersiloxane copolymer 0.2-1.0 parts a defoamer, e.g. B. a silicone defoamer or a siloxane-free defoamer; 0.3-0.5 parts a leveling agent, e.g.
• the adhesive layer(s) and/or the lacquer layer(s) may be colored.
• the lacquer layer(s) and/or the adhesive layer(s) can contain one or more coloring components such as organic and/or inorganic pigments or dyes.
• these pigments are titanium dioxide as a white pigment, iron oxide pigments such as iron oxide yellow, iron oxide red, iron oxide black, black pigments such as carbon black, phthalocyanine pigments such as heliogen blue or heliogen green, bismuth pigments such as bismuth vanadate yellow and diketopyrrolopyrrole red.
• Metal pigments such as iron pigments, pearlescent pigments and aluminum pigments can also be included for metallization effects.
• Preferred pigments typically have particle sizes in the range from 0.1 to 100 ⁇ m, in particular in the range from 1 to 50 ⁇ m.
• Adhesive layers typically have layer thicknesses in the range from 5 to 25 ⁇ m.
• the thermal transfer films according to the invention naturally have at least one carrier film on which the at least one lacquer layer is arranged.
• the carrier foils are usually plastic foils made from thermoplastic, flexible polymers. In particular, these are polyester films, polyamide films, polypropylene films, films made from polyvinyl alcohol or polyesteramide films. So-called coextrudate films are also suitable, i. H. foils consisting of several layers, whereby the plastic material in the individual layers can be different.
• the plastic material forming the carrier film is predominantly amorphous. Waxed or siliconized papers are also suitable.
• the carrier film (2) preferably has a thickness in the range from 3 to 200 ⁇ m, in particular from 10 to 100 ⁇ m and especially from 20 to 50 ⁇ m. Thin carrier films with film thicknesses in the range from 3 to 30 ⁇ m are also suitable.
• the surface structure of the carrier film on which the layer of lacquer is arranged naturally determines the degree of gloss of the layer of lacquer which is obtained in the coating method according to the invention. Smooth surfaces lead to glossy or high-gloss surfaces, whereas rough surfaces can produce matt effects. It is possible to create coarser structures in the paint surface by heavily structuring the surface.
• the surface of the carrier film on which the lacquer layer is arranged can have a customary release layer, which facilitates the detachment of the lacquer layer from the carrier film in the coating method according to the invention.
• the thermal transfer foils can be produced in analogy to conventional foil coating technologies, as also described in the prior art cited at the outset, with the difference that no heat drying step is carried out in the production of the lacquer layer, but rather by applying the non-aqueous, radiation-curable, liquid Composition on the carrier film obtained liquid paint layer is at least partially cured by treatment with high-energy radiation such as electron beams or UV radiation.
• the non-aqueous, radiation-curable, liquid composition can be applied to the carrier film in step i) of the process according to the invention in a manner known per se, for example by knife-coating, rolling, pouring or spraying. In this way, a coating of the carrier film with the radiation-curable composition is obtained, which can then be cured by treatment with high-energy radiation.
• the application quantity is usually selected in such a way that a layer thickness in the ranges mentioned above results. As a rule, the amount applied is in the range from 10 to 120 g/m 2 , in particular in the range from 30 to 80 g/m 2 and, in the case of several layers, preferably in the range from 10 to 100 g/m 2 and in particular 20 to 70 g/m 2 m2 .
• step ii) of the method according to the invention the coating obtained in step i) is then high-energy radiation at least partially cured.
• a decorative layer can be applied to the not yet cured or partially cured coating.
• the adhesive layer can also be applied before curing.
• step ii) of the method according to the invention the coating obtained in step i) is preferably only partially cured. Preferably, however, the layer obtained in step i) is at least partially cured before the application of the heat-sealable, polymeric adhesive layer and before the optional application of the decorative layer.
• the coating obtained in step i) is irradiated with high-energy radiation.
• the irradiation can take place through the carrier film or by direct irradiation of the coating. Direct irradiation is preferred.
• the irradiation can take place by means of electron beams or with UV light, for example with UV lamps or light-emitting diodes emitting UV radiation.
• UV radiation is preferably used for curing in step ii). In particular, UV radiation in the wavelength range from 200 to 400 nm is used.
• Medium-pressure or high-pressure mercury lamps are preferably used for this purpose. In many cases, high-pressure mercury lamps doped with gallium or iron are used.
• the irradiation in step ii) is preferably carried out in such a way that only partial polymerization of the ethylenically unsaturated double bonds present in the nonaqueous, radiation-curable, liquid composition takes place.
• the radiation density required for this can be determined by a person skilled in the art through routine experiments.
• the irradiation in step ii) takes place at a radiation density in the range from 80 to 2000 J/m 2 , in particular in the range from 110 to 400 J/m 2 .
• the curing in step ii) can be carried out under an air atmosphere or under a low-oxygen atmosphere with residual oxygen concentrations below 2000 ppm, e.g. B. at residual oxygen concentrations in the range of 50 to 1000 ppm. Curing preferably takes place in air.
• the individual layers of lacquer can be applied, for example, in a liquid-liquid application, i. H. the second coat of paint and any further coats of paint are applied to the still liquid first coating before curing.
• the first lacquer layer is preferably at least partially cured by high-energy radiation before the further lacquer layer(s) are applied.
• a decorative layer is applied to the layer of paint before the application of the adhesive layer or, in the case of several layers of paint, also to the first layer of paint.
• This decorative layer can be applied in a manner known per se using suitable printing methods, for example flat, gravure, inkjet or digital printing.
• the lacquer layer is preferably partially cured before the decorative layer is applied, the partial curing preferably being carried out only to the extent that the decorative layer can just still be applied.
• the printing inks used to produce the decorative layer can be conventional printing inks or UV-curing printing inks.
• the heat-sealable adhesive layer can be applied in step iv) of the method according to the invention in a manner known per se.
• a liquid adhesive composition in particular an aqueous adhesive composition
• the adhesive layer is then dried, for example by heat.
• the amount of liquid adhesive composition applied is generally chosen so that, after drying, a layer thickness in the above-mentioned ranges results.
• the amount applied is generally in the range from 5 to 50 g of solids per m 2 , in particular in the range from 5 to 15 g of solids per m 2 .
• the following film structures 1 to 12 can be produced with the method according to the invention by using the steps specified there.
• the film structures 7 to 12 correspond to the film structures 1 to 6 with the difference that a pigment-containing adhesive composition is used.
• thermal transfer films thus obtained can then be finished in the usual way, e.g. B. be wound into rolls.
• the thermal transfer films according to the invention are particularly suitable for dry coating of the surfaces of objects.
• the paint layer or layers of paint are transferred to the surface of the object to be coated, hereinafter also referred to as the substrate, by means of heat and/or pressure, with the adhesive layer providing a good adhesive bond between the or the paint layers and the substrate causes.
• the use of the thermal transfer foils according to the invention is not limited to certain substrates, but they can be used in a wide variety of ways, both with hard and with elastic substrates.
• the substrates can be, for example, objects made of plastic, for example ABS, polycarbonate, melamine, polyester, including glass fiber reinforced polyester, hard PVC, soft PVC, rubber, wood including exotic natural wood, wood-based materials, e.g. As veneer, MDF, HDF, chipboard or multiplex boards, mineral fibers, z. As mineral fiber boards, paper, textiles including artificial leather, metal or plastic-coated materials act.
• the thermal transfer films according to the invention are preferably suitable for smooth, preferably flat or slightly curved surfaces. In principle, however, more complex structures can also be coated in this way.
• the substrates to be coated can be undecorated or already have decorative surfaces.
• Exotic natural woods which often cause problems in wet painting, can be coated particularly advantageously using the thermal transfer films according to the invention, since the ingredients bleed out or adhesion problems are caused.
• the objects coated using the thermal transfer films according to the invention e.g. B. wood fiber boards, MDF boards or natural wood boards, which have been primed using the thermal transfer films according to the invention, can easily be further coated with a conventional UV varnish, with no intermediate sanding being required.
• an object primed in this way can also be dry-coated with a thermal transfer film according to the invention.
• the thermal transfer films according to the invention allow objects to be coated with almost no waste.
• a change from colorless to colored, from matt to glossy can take place very quickly without a cleaning step being necessary between this change. Drying times are eliminated and work can continue immediately after coating, e.g. B. applied a conventional coat of paint or the coated object are packaged.
• the carrier film can be detached or initially remain on the coated surface as a protective film.
• the use of the thermal transfer foils according to the invention allows dust-free coating.
• the space requirement and personnel costs are much lower compared to conventional painting processes.
• the thermal transfer foils according to the invention provide surfaces with a particularly high quality, in particular high scratch and abrasion resistance.
• surfaces of quality classes AC3 to AC4 can be achieved.
• the surfaces obtained using the thermal transfer films according to the invention regularly show values above 20 N when tested with the Hamberger planer. The surfaces obtained in this way regularly meet the requirements of the highest stress group of the furniture standard DIN 68861.
• thermal transfer foils according to the invention for coating surfaces of objects is typically carried out in a process which comprises the aforementioned steps a) to d), which are described in more detail below and which are carried out analogously to in EP 2078618 A2 described procedure can be carried out.
• steps a) to d which are described in more detail below and which are carried out analogously to in EP 2078618 A2 described procedure can be carried out.
• EP 2078618 A2 is hereby referred to.
• the thermal transfer film according to the invention is first applied to the surface of the substrate to be coated and then heat-sealed.
• Heat sealing is typically carried out using pressure in suitable presses, the temperature of the press typically being in the range 100 to 250°C, preferably in the range 160 to 220°C.
• Roller presses are preferred, since only brief contact is required in this way, so that the object temperature does not exceed a value of 70° C., in particular 60° C.
• Heat-sensitive substrates can also be coated in this way.
• the substrate coated in this way is then exposed to high-energy radiation, i. H. with UV or electron beams, whereupon the lacquer layer hardens completely.
• the irradiation can be carried out before removing the carrier film or afterwards.
• it is advantageous to carry out the irradiation before removing the carrier film since the carrier film then remains on the coated substrate as a protective film.
• the irradiation can be done by means of electron beams, e.g. B. using gallium emitters or UV light, for example with UV lamps or UV radiation emitting light-emitting diodes.
• UV radiation is preferably used for curing in step ii). In particular, UV radiation in the wavelength range from 200 to 400 nm is used.
• Medium-pressure or high-pressure mercury lamps are preferably used for this purpose. In many cases, high-pressure mercury lamps doped with gallium or iron are used.
• the irradiation in step ii) takes place at a radiation density in the range from 40 to 2000 J/m 2 , in particular in the range from 100 to 400 J/m 2 .
• a system for carrying out the method according to the invention comprises at least one thermal transfer device which is usually used and which preferably has a cutting device and/or a winding device for the carrier film.
• the plant may have a first thermal transfer device with which the object is primed and a second thermal transfer device with which the object is top-coated.
• a conventional thermal transfer device can be constructed as follows: the thermal transfer foil wound up as a roll is guided from a foil unwinding device to a heated roller press which has at least one driven, heated, optionally rubberized roller, which is optionally height-adjustable.
• the roller press generally has a counter-pressure roller which is opposite the heated roller and which can be rubberized. This creates the necessary pressure, whereby the layer of paint is transferred by means of the adhesive layer to the surface of an object that is guided between the two rollers.
• the counter-pressure roller can be designed in such a way that it separates the carrier film from the lacquer layer. The separated carrier film can be removed with a cutting device or fed to a film winding device.
• a platen press can also be used, which is opened after a predetermined time.
• the coated object is then passed with the coated side past a source of high-energy radiation, for example an electron beam or a UV lamp, whereby the coated side of the object is exposed to high-energy radiation and final curing is achieved.
• a source of high-energy radiation for example an electron beam or a UV lamp
• the object coated in this way is then fed to a collecting device, for example a stacking device.
• the carrier film can be removed with a cutting device or fed to a film winding device.
• the object coated in the thermal transfer device can also be fed to a further thermal transfer device before or after curing by means of high-energy radiation, in which another layer of lacquer is applied to the coated surface of the object using a further thermal transfer film according to the invention. Curing with high-energy radiation preferably takes place after the application of the further lacquer layer, as described above.
• a first embodiment of a device for continuously carrying out the method according to the invention with solid substrates has a loading conveyor belt, an unwinding station for the thermal transfer film wound up as a roll, a thermal transfer device with a roller press, as described above, a winding device for the carrier film, a drying tunnel with UV emitter , an outfeed conveyor and a stacking device.
• the substrates to be coated are placed on the conveyor belt and fed through the thermal transfer device at the desired feed rate.
• the lacquer layer is transferred to the substrate and the carrier film is separated and picked up by the winding device.
• the paint layer is then cured in the drying tunnel.
• the winding station can also be arranged after the drying tunnel, so that the carrier film initially remains on the substrate and acts there as a protective film.
• a second embodiment of a device for continuously carrying out the method according to the invention with elastic substrates has an unwinding station for the substrate, an unwinding station for the thermal transfer film wound up as a roll, a thermal transfer device with a roller press, as described above, a drying tunnel with a UV emitter and a winding device for the coated substrate.
• the substrate to be coated is fed through the thermal transfer device together with the thermal transfer film at the desired feed rate.
• the thermal transfer film is connected to the substrate.
• the substrate coated in this way is then fed through the drying tunnel, causing the layer of paint to harden and is picked up by the winding station. After cutting, the carrier film can be removed.
• a third embodiment of a device for continuously carrying out the method according to the invention with solid substrates has a conveyor belt, an unwinding station for the thermal transfer foil wound up as a roll, a thermal transfer device with a heated platen press and, if necessary, a winding device for the carrier foil or a cutting device.
• the substrates to be coated are placed on the conveyor belt and fed into the platen press together with the thermal transfer foil.
• the press is closed and the desired pressure is applied.
• the lacquer layer is transferred to the substrate.
• the substrate is moved out of the press and passed through the drying tunnel, causing the paint layer to harden.
• the carrier film can remain on the substrate and serve as a protective film.
• the carrier foil can be cut with a cutting device before or after the drying tunnel. Alternatively, it is possible to place the film as a whole in front of the UV channel cut off and fed to the winding device.
• a further embodiment of a device for discontinuously carrying out the method according to the invention with solid substrates has a conveyor belt, an unwinding station for the thermal transfer film wound up as a roll, a cutting device, thermal transfer device with heated platen press and a drying tunnel with UV emitter.
• the substrate to be coated is placed on the conveyor belt.
• the thermal transfer foil is unwound to the desired length, placed with the adhesive layer on the substrate to be coated and cut off.
• Substrate and film are fed into the platen press.
• the press is closed and the desired pressure is applied.
• the lacquer layer is transferred to the substrate.
• the coated substrate is moved out of the press and passed through the drying tunnel, causing the paint layer to harden.
• the carrier film can remain on the substrate and serve as a protective film. Alternatively, it is possible to separate the film in front of the UV channel.
• FIGS EP 2078618 A2 For further details on this, reference is made in particular to FIGS EP 2078618 A2 and the explanations given there.
• the following radiation-curable coating formulations 1 to 7 were prepared by mixing the raw materials mentioned above: Paint formulation 1: raw material Amount [% by weight] 1) Urethane acrylate diluted with 35% by weight dipropylene glycol diacrylate, functionality 2.0 30.0 Polyester acrylate 1, functionality 3.3 9.0 Trimethylolpropane formal monoacrylate 9.8 trimethylolpropane triacrylate 13.0 Aliphatic urethane acrylate 2 diluted with 30 8.5 % by weight of trimethylolpropane formal monoacrylate, functionality 1.7 aluminum oxide (corundum) 25.0 deaerator concentrate 0.5 Fumed silica 1.0 phenyl glyoxylate 1.6 acylphosphine oxide 0.4 alpha-hydroxyalkylphenone 1.0 1) based on the total weight of the composition raw material Amount [% by weight] 1) Urethane acrylate diluted with 35% by weight dipropylene glycol diacrylate, functionality 2.0 37.0 Aliphatic urethane acrylate 2 diluted with 30%
• Adhesive composition 1 was prepared by mixing the components listed in the table below.
• Adhesive formulation 1 raw material Amount [% by weight] 1) Self-crosslinking aqueous polyacrylate dispersion 1 39.0 Aqueous polyetherurethane acrylate dispersion 1 16.4 Polyethersiloxane Emulsion 0.44 Polymeric fluorosurfactant 0.35 carnauba wax dispersion 1.20 Modified polyethylene wax 7.3 Fumed silica 1.5 Synthetic silica 1.3 Micronized polyethylene wax 1.7 polyurethane dispersion 13.0 dimethylpolysiloxane 0.4 Aliphatic epoxy acrylate 6.1 Styrene acrylate dispersion (50%) 4.4 triethyl citrate 1.75 alpha-hydroxyalkylphenone 1.0 acylphosphine oxide 0.7 benzophenone 0.85 butyl glycol 1.0 water 1.0 amino alcohol 0.17 1) based on the total weight of the composition
• Adhesive formulation 2 was prepared by mixing the components listed in the table below.
• Adhesive formulation 3 (not according to the invention) was prepared by mixing the components listed in the table below.
• Adhesive formulation 3 (not according to the invention) raw material Amount [% by weight] 1) Aqueous polyester urethane dispersion 57.5 Aqueous polyetherurethane acrylate dispersion 1 35.8 Wetting additive 1 0.1 Wetting additive 2 0.8 defoamer: 0.1 acylphosphine oxide 0.75 Mixture of benzophenone and 1-hydroxycyclohexyl phenyl ketone 2.0 thickener 0.05
• Adhesive formulation 4 was prepared by mixing the components listed in the table below.
• a device was used for the irradiation, in which the coated or printed film was fed past a Ga-doped mercury lamp with a power of 120 W/cm at a defined feed rate.
• Example 1 Film for use as a colored lacquer in the furniture sector
• Coating formulation 4 was applied in a layer thickness of 40 g/m 2 to an uncolored polyethylene terephthalate carrier film in a layer thickness of 23 ⁇ m. The film coated in this way was guided past the Ga-doped mercury radiator at a feed rate of 30 m/min to gel the lacquer layer.
• the UV-curable gravure printing ink was then applied to the gelled lacquer layer.
• the film printed in this way was passed again past the Ga-doped mercury radiator at a feed rate of 30 m/min.
• Adhesive formulation 3 was then applied to the printed lacquer layer in a layer thickness of 15 g/m 2 and dried thermally.
• Example 2 Film for use as a colored lacquer in the furniture sector
• Coating formulation 5 was applied in a layer thickness of 70 g/m 2 to an uncolored polyethylene terephthalate carrier film in a layer thickness of 23 ⁇ m. The film coated in this way was guided past the Ga-doped mercury radiator at a feed rate of 30 m/min to gel the lacquer layer.
• the UV-curable gravure printing ink was then applied to the gelled lacquer layer.
• the film printed in this way was passed again past the Ga-doped mercury radiator at a feed rate of 30 m/min.
• Adhesive formulation 3 was then applied to the printed lacquer layer in a layer thickness of 15 g/m 2 and dried thermally.
• Coating formulation 6 was applied in a layer thickness of 40 g/m 2 to an uncolored polyethylene terephthalate carrier film in a layer thickness of 23 ⁇ m. The film coated in this way was guided past the Ga-doped mercury radiator at a feed rate of 30 m/min to gel the lacquer layer.
• Example 3 Film for use as a clear lacquer in the furniture sector
• Adhesive formulation 3 was then applied to the printed lacquer layer in a layer thickness of 15 g/m 2 and dried thermally.
• Coating formulation 7 was applied in a layer thickness of 45 g/m 2 to an uncolored polyethylene terephthalate carrier film in a layer thickness of 23 ⁇ m. The film coated in this way was guided past the Ga-doped mercury radiator at a feed rate of 30 m/min to gel the lacquer layer.
• the UV-curable gravure printing ink was then applied to the gelled lacquer layer.
• the film printed in this way was passed again past the Ga-doped mercury radiator at a feed rate of 30 m/min.
• Example 4 Film for outdoor use as a colored lacquer
• Adhesive formulation 3 was then applied to the printed lacquer layer in a layer thickness of 15 g/m 2 and dried thermally.
• the film from Example 3 was laminated to a beech wood panel using a heated roller (180° C., maximum object temperature 50° C.).
• the film laminated in this way was then irradiated through the film by passing the laminated side at a feed rate of 20 m/min to two UV lamps (mercury lamp and Ga-doped mercury lamp) each with an output of 120 W/cm.
• the sample obtained in this way was analyzed by means of ATR-FTIR spectroscopy using a Nicolet FT-IR spectrometer (Nicolet 380) and a Golden Gate® probe head. Compared to a non-irradiated sample, there was a significant reduction in the absorption bands at 810 cm-1 (> 40%) and 1410 cm-1 (> 30%) that are characteristic of acrylate groups.
• Example 1 The film from Example 1 was laminated to an MDF board using a heated roller (180° C., maximum object temperature 50° C.) with constant contact pressure. The sheet laminated in this way was then irradiated through the film by moving the laminated side past two UV lamps (mercury lamp and Ga-doped mercury lamp) with a power of 120 W/cm each at a feed rate of 20 m/min. The backing film was then removed.
• UV lamps mercury lamp and Ga-doped mercury lamp
• Example 1 For comparison purposes, the film from Example 1 was laminated to an MDF board using a heated roller (180° C., maximum object temperature 50° C.) with the same contact pressure, but no subsequent irradiation was carried out.
• the production took place analogously to the production of sample 1, the film from example 2 being used instead of the film from example 1.
• the film from Example 3 was laminated to a beech wood panel using a heated roller (180° C., maximum object temperature 50° C.) with constant contact pressure.
• the sheet laminated in this way was then irradiated through the film by moving the laminated side past two UV lamps (mercury lamp and Ga-doped mercury lamp) with a power of 120 W/cm each at a feed rate of 20 m/min.
• the backing film was then removed.
• Example 3 For comparison purposes, the film from Example 3 was laminated to a beechwood panel using a heated roller (180° C., maximum object temperature 50° C.) with the same contact pressure, but no subsequent irradiation was carried out.
• the film from Example 43 was laminated to a PVC sheet using a heated roller (180° C., maximum object temperature 50° C.) with constant contact pressure.
• the sheet laminated in this way was then irradiated through the film by moving the laminated side past two UV lamps (mercury lamp and Ga-doped mercury lamp) with a power of 120 W/cm each at a feed rate of 15 m/min.
• the backing film was then removed.

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• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Laminated Bodies (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Paints Or Removers (AREA)
• Adhesives Or Adhesive Processes (AREA)
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• 2014
  • 2014-09-18 WO PCT/EP2014/069895 patent/WO2015040113A1/de active Application Filing
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  • 2014-09-18 US US14/917,980 patent/US20160297226A1/en not_active Abandoned
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• 2019
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