MAGENTA INK COMPOSITION FOR DECORATING NON-POROUS SUBSTRATES

Abstract

MAGENTA INK COMPOSITION FOR DECORATING NON-POROUS SUBSTRATES, in particular an ink composition containing an organic solvent as a carrier which is liquid at room temperature, a gold compound soluble in the liquid medium of the ink, a binder composition with submicrometric particles of a glass frit, submicrometric particles of oxides or inorganic primary materials and additives. Said ink is intended for printing by means of injection technology on non-porous surfaces in general which are subjected to a heat treatment which allows a magenta coloration to develop which is permanent and resistant to abrasion, cleaning agents and weathering.

Claims

1. An ink composition intended for printing by means of injection technology on non-porous surfaces subjected to a heat treatment after the printing thereof to develop a magenta coloration, comprising: a. at least one organic solvent as a carrier which is a liquid medium at room temperature, b. at least one gold compound soluble in the at least said one organic solvent, c. at least one binder composition with submicrometric particles of a glass frit, d. at least submicrometric particles of oxides or inorganic primary materials and e. at least one additive selected from dispersing agents, thickening agents, humectants or wetting agents, levelling agents and anti-foaming agents or a mixture of these.

2. The ink composition according to claim 1, wherein the percentage by weight of the solvent is between 35% and 55%.

3. The ink composition according to claim 2, wherein the solvent is an apolar organic solvent or a mixture of apolar organic solvents and solvents with low and/or medium polarity.

4. The ink composition according to claim 1, wherein the percentage by weight of the gold compound soluble in the liquid medium of the composition is between 0.45% and 15%, preferably between 0.9% and 10% and the percentage by weight of gold in the composition is between 0.3% and 1.5%, preferably 0.6% and 1%.

5. The ink composition according to claim 1, wherein the gold compound soluble in the liquid medium of the composition is an organometallic gold compound.

6. The ink composition according to claim 5, wherein the percentage by weight of gold in the organometallic compound is between 10% and 65%.

7. The ink composition according to claim 1, wherein the percentage by weight of the submicrometric glass frit particles is between 31% and 50%.

8. The ink composition according to claim 1, wherein the percentage by weight of the submicrometric oxides and inorganic primary materials is between 1% and 9%.

9. The ink composition according to claim 1, wherein the percentage by weight of the submicrometric particles is up to 50%, preferably between 40% and 50%.

10. The ink composition according to claim 1, wherein the particle size of the submicrometric particles is up to 0.750 micrometers, preferably up to 0.500 micrometers.

11. The ink composition according to claim 1, wherein the dispersing or hyperdispersing agent is found in the composition in a percentage of up to 10% by weight.

12. The ink composition according to claim 1, wherein the thickening agent is found in the composition in a percentage of up to 3% by weight.

13. The ink composition according to claim 1, wherein the humectant or wetting agent is found in the composition in a percentage of up to 2% by weight.

14. The ink composition according to claim 1, wherein the leveling agent is found in the composition in a percentage of up to 2% by weight.

15. The ink composition according to claim 1, wherein the anti-foaming agent is found in the composition in a percentage of up to 0.25% by weight.

16. The ink composition according to claim 1, wherein the magenta colorations which are obtained once the heat treatment has been carried out have colorimetric values in terms of La*b* coordinates of between 30 and 50 for the L coordinate, between 8 and 50 for the a* coordinate and between 6 and 18 for the b* coordinate.

17. The ink composition according to claim 1, wherein it has a sedimentation speed of up to 0.11% and preferably between 0.09% and 0.06%.

18. The ink composition according to claim 1, wherein it has a drying speed of between 12% and 20% at 10 minutes.

19. The ink composition according to claim 1, wherein the viscosity is up to 20 cP at 22 C.

Description

DESCRIPTION OF THE INVENTION

[0018] The present invention relates to an inorganic ink composition for decorating non-porous substrates by means of ink injection technology which includes, according to the content of claim 1, at least one organic solvent, at least one organometallic gold compound soluble in the solvent, at least one binder composition of glass frit, at least oxides or inorganic primary materials and at least one additive selected from dispersing agents, foaming agents, humectants or wetting agents, levelling agents and anti-foaming agents. Once the non-porous surface of said substrate has been printed, it is subjected to a heat treatment no lower than 500 C. so that the ink is adhered to the substrate and the final magenta color is produced. The adherence which is achieved with the heat treatment is such that the magenta decoration developed is permanent and resistant to abrasion, cleaning agents and weathering. The duration of the heat treatment depends on the nature of the non-porous surface to be treated.

[0019] According to the present invention, the organic solvent used as a carrier that is liquid at room temperature is found in the ink in a percentage by weight of between 35% and 55% and may be apolar or a mixture of apolar solvents and solvents with low and/or medium polarity. Apolar solvents include linear and/or branched aliphatic hydrocarbons, aromatic hydrocarbons, naphthenic hydrocarbons and natural oils or mixtures of these. In terms of the solvents with low or medium polarity, they are selected from glycols, glycol ethers, glycol esters, alcohols, ketones, carboxylic acids, organic acids, esters or a mixture of these.

[0020] The organometallic gold compound is characterized by being soluble in the liquid medium of the ink and is found in a percentage by weight in the ink of between 0.45% and 15%, preferably between 0.9% and 10%, providing as a source of gold, a percentage by weight of gold in the ink of between 0.3% and 1.5%, preferably between 0.6% and 1%.

[0021] An organometallic gold compound is understood as a compound formed by gold bonded to one or various carbon chains termed binders. The binders bonded to the gold may be from the following families: mercaptates, polycyclic mercaptates, mercapto esters, alkoxides, sulfurs, sulfur resonates, natural resonates, synthetic resonates, natural sulfur resonates, synthetic sulfur resonates, terpenes, sulfurized terpenes, terpene thiols, thiolates, linear thiols, cyclic thiols, mercapto pyridines, mercapto pyrimidines, mercapto imidazoles, carboxylates, phosphines and the derivatives thereof soluble in organic mediums, cyanates, mercaptocarboxylic acids, polyalkyl sulfur, amines and/or combinations of binders of said families.

[0022] Preferably, they may be from the following families: mercaptates, polycyclic mercaptates, mercapto esters, alkoxides, sulfurs, natural resonates, synthetic resonates, natural sulfur resonates, synthetic sulfur resonates, terpenes, sulfurized terpenes, terpene thiols, thiolates, linear thiols, cyclic thiols, and/or combinations of binders of said families. Depending on the binder or binders, the percentage by weight of gold in the organometallic compound is between 10% and 65%.

[0023] The present invention also includes the use of a binder composition of glass frits with a submicrometric particle size required in order for the print design on the non-porous surface to have sufficient shine, adherence and inalterability against common agents and attacks. In this sense, the percentage by weight of the submicrometric frits is between 31% and 50% of the total weight of the ink and are mainly composed of oxides and salts of Si, Bi, Zn, Ti or Sn or combinations of these.

[0024] The ink according to the present invention has in its formulation oxides and inorganic primary materials with a submicrometric size required for, combined with the gold compound, producing the correct opacity and magenta coloration. These oxides and inorganic primary materials are found in the ink in a percentage by weight of between 1% and 9% and are selected from zirconium oxide, zinc oxide, silicon oxide, titanium oxide, cerium oxide and tin oxide or a mixture of these. Preferably, they are selected from silicon oxide, titanium oxide and tin oxide.

[0025] According to the present invention, the percentage by weight of the submicrometric particles in the ink is up to 50%, preferably between 40% and 50% and the particle size of the same is up to 0.750 micrometers, preferably up to 0.500 micrometers.

[0026] Likewise, the liquid part may contain different additives which fulfil different functions. The following may be distinguished among these additives: dispersing or hyperdispersing agents, thickening agents, humectants or wetting agents, levelling agents or anti-foaming agents.

[0027] The function of the dispersing or hyperdispersing agents is to prevent clumping in the ink of the submicrometric particles and in the cases in which it is used, it is found in the ink in a percentage of up to 10% by weight. The dispersing agent is selected from carboxylic acid copolymers, acrylic copolymers, polymeric fatty esters, polymeric esters, acidic polyesters, polyamide salts, alkyl ammonium salts, polycarboxylic acids, polycarboxylic acid esters, polyamides, modified polyurethanes, phosphoric esters or a mixture of these.

[0028] The function of the thickening agent is to increase the viscosity of the ink at low shear gradients, increasing the definition and improving the sedimentation and may be found in a percentage by weight of up to 3% of the total weight of the ink. The thickening agent is selected from polyamide, polyamide derivatives, acrylic resins, carboxylated acrylic resins, pyrrolidone derivatives, polyvinyl pyrrolidone and the derivatives thereof, polyvinyl butyral, condensates of urea and aldehydes, urea derivatives, polyvinyl resins, cellulose derivatives, cellulose acetate butyrate, polyamide derivatives, acrylic polymer derivatives, phenolic resins, alkyl phenolic resins, alkyd resins, colophony resins, oleoresins, maleates, polyester resins and the derivatives thereof or a mixture of these.

[0029] The humectant or wetting agent modifies the surface tension of the liquid medium, thus facilitating the wetting of the surface of the submicrometric solid particles by the solvent. It may be found in the ink in a percentage by weight of up to 2% and is selected from polydimethylsiloxane modified with polyether, fluorinated derivatives, alkoxylated alcohols, ethylene and polyethylene oxide copolymers and polydimethylsiloxane modified with polyester or a mixture of these.

[0030] The levelling agent is used to reduce the roughness of the application. According to the present invention, in the cases in which the levelling agent is used, it is found in the ink in a percentage by weight of up to 2% and is selected from acrylic copolymers, acrylic derivatives and modified polysiloxanes or a mixture of these.

[0031] The function of the anti-foaming agent is to prevent the formation of foam and in the cases in which it is used, it is found in the ink in a percentage by weight of up to 0.25% and is selected from polysiloxanes and polysiloxanes modified with polyether or a mixture of these.

[0032] The ink according to the invention is characterized by developing a magenta coloration on the non-porous, decorated surface and once it has been subjected to heat treatment, the resulting coloration has colorimetric values in terms of CieLa*b* coordinates of between 30 and 50 for the L coordinate, between 8 and 50 for the a* coordinate and 6 and 18 for the b* coordinate. The measurement of the CieLa*b* coordinates is carried out by means of spectrophotometry (Minolta or similar) and the results are expressed in values of L, a* and b*.

[0033] According to the present invention, the ink is characterized by a sedimentation speed lower than 0.11%, preferably between 0.09% and 0.06% as well as a drying speed of between 12% and 20% at 10 minutes.

[0034] The sedimentation speed is determined with a liquid dispersion stability optical analyzer (Turbiscan or similar) and expresses the results as % by weight of ink sedimented in one hour. The measurement is taken at 3 days and the value is divided by the 72 hours of these three days.

[0035] The sedimentation speed results from the ink composition according to the invention and in particular from the thickening agent used as well as from the solvents used, the size of the particles and the remaining additives used.

[0036] In terms of determining the drying speed, this is carried out by means of an electronic thermobalance on which a determined quantity of ink placed in a glass of precipitates is weighed and maintained at 100 C. After 10 minutes, it is weighed and the weight of ink, which has evaporate, is determined by the difference, expressed in a percentage.

[0037] The drying speed results, fundamentally, from the apolar solvents or a mixture of apolar solvents and solvents with low and/or medium polarity used according to the invention.

[0038] Given that the ink according to the present invention is intended for printing by means of injection technology, the viscosity of the same must be less than 20 cP at 22 C. The measurement of the viscosity at a determined temperature is carried out by means of rotational rheometry (Anton Paar MCR101 or similar).

Preferred Embodiments

[0039] In order to complement the description being made and with the aim of helping to better understand its characteristics, various exemplary embodiments of inks for providing magenta colored designs according to the invention accompany the present specification. In the examples, the different components, which the ink may include, are indicated as well as the range of the percentage by weight of each one of these in the formulation of the ink. In the case of the organometallic gold components, the percentage by weight of gold in the same is indicated.

[0040] All the exemplary embodiments indicated are illustrative and non-limiting. Five solutions of organometallic gold compounds and metal oxide frits with the characteristics indicated in the description of the invention are prepared, dissolving said compounds in apolar solvents and in a mixture of apolar solvents and solvents with low and/or medium polarity in the proportions indicated in the table below:

TABLE-US-00001 Designation Component 1 2 3 4 5 6 Organometallic Mercapto ester of Au (21% Au) 1.4% 2.9% 2.9% gold 1 Organometallic Mercaptate of Au (50% Au) 2% 3% 2% gold 2 Solvent 1 Linear aliphatic hydrocarbon 20-40% 20-40% 15-35% 15-35% 20-55% 15-35% Solvent 2 Ester 5-15% 5-15% 5-15% 5-15% 5-15% Solvent 3 Terpene solvent 5-10% 5-10% 5-10% Frit 1 Oxides of Bi and Si 15-20% 20-30% 15-25% 20-30% 20-30% 31-50% Frit 2 Oxides of Zn and Si 6-25% 5-15% 5-15% 5-15% 5-15% SiO.sub.2 Oxide of Si 0-4% 0-4% 0-4% 0-4% 0-4% 0-4% TiO.sub.2 Oxide of Ti 1-6% 1-6% 1-6% 1-6% 1-6% 1-6% SnO.sub.2 Oxide of Sn 0-3% 0-3% 0-3% 0-3% 0-3% 0-3% Bi.sub.2O.sub.3 Oxide of Bi 5-10% Dispersing Acrylic copolymer <10% <10% <10% <10% <10% <10% agent Thickening Acrylic derivative <3% <3% <3% <3% <3% <3% agent Humectant Ethylene and polyethylene oxide <2% <2% <2% <2% <2% <2% copolymers Levelling agent Modified polysiloxane <2% <2% <2% <2% <2% <2% Anti-foaming Polysiloxane <0.25% <0.25% <0.25% <0.25% <0.25% <0.25% agent

[0041] Using said compositions, the inks according to the invention present the following physical properties:

TABLE-US-00002 Property 1 2 3 4 5 6 % by weight of Au in the ink 0.3% 0.6% 1% 1.5% 0.6% 1% Viscosity at 22 C. (cP) 12 13 14 14 14 14 Sedimentation speed (%/h) 0.060% 0.075% 0.065% 0.075% 0.070% 0.0650% Drying speed (% at 10 minutes) 14% 16% 12% 13% 17% 12% L 38.1 41.3 42.5 42.7 41.2 41 a* 8.4 11.8 14.2 50.1 11.8 12.5 b* 9.1 10.5 8.5 23.0 10.5 7.75

[0042] The characteristics disclosed in the description and the claims may be important both separately and in any combination for implementing the invention in the different embodiments thereof.

[0043] The preparation of the magenta inks with the components indicated is carried out by means of the conventional methods generally used in the industry.