Patent Application
20150038616
The present invention relates to an ink composition for decorating non-porous substrates in which the surfaces of said substrates are subjected to heat treatment after printing.
The non-porous substrates are characterized by being stable during heat treatment and include, among others, materials such as glass, ceramic materials (glazed tiles, floor tiles, etc.), glass-ceramic plates, aluminum, steels and metal sheets, in general.
The present invention belongs to the sector of inks for printing on non-porous substrates.
Today, there are several printing processes and various inks for decorating non-porous surfaces in general. The present invention relates to a process for printing on non-porous surfaces using inorganic inks which use ceramic pigments (mineral-based oxides and crystalline structures) and ground glass particles, referred to as frits.
In terms of processes that use inorganic inks for decorating non-porous surfaces, once printed, they are heated up until the frits of the ink melt, so that the pigments contained in said inks combine with the surface of the non-porous substrate and thus provide the printed motif with the necessary and desired permanency and inalterability with respect to common attacks and agents.
It must be highlighted that referring to the inks as inorganic inks does not exclude the fact that their composition includes organic compounds generally used as solvents or vehicles for the application of the ink and which generally evaporate when firing the non-porous substrate.
In the state of the art preceding the present invention, inks for decorating non-porous surfaces are disclosed in which their composition is typically formed by organic solvents, ceramic pigments and a glass frit. Therefore, U.S. Pat. No. 5,407,474 discloses an ink for ceramic surfaces including an organic solvent, ceramic pigments and a glass frit. Document U.S. Pat. No. 5,407,474 discloses deionized water or organic compounds incorporating functional groups, such as alcohol or acetone, as a solvent.
Japanese patent JP-2002-97069 in turn discloses an ink for ceramic surfaces including an organic solvent, ceramic pigments and a glass frit. Document JP-2002-97069 discloses organic compounds incorporating functional groups, such as glycol, ether and others, as a solvent.
Furthermore, Japanese patent JP-64-56776 discloses an ink for ceramic surfaces including an organic solvent, ceramic pigments and a glass frit. Document JP-64-56776 discloses organic compounds based on alcohols, ethers, esters, acetone and aromatic compounds, in which functional groups are present, as a solvent.
Likewise, international application WO2005018941 discloses an ink for ceramic surfaces including an organic solvent, ceramic pigments and a glass frit. Document WO2005018941 discloses organic compounds incorporating functional groups, such as glycol or ester, as a solvent.
The particle sizes of both the ceramic pigment and the glass frit of all these inks are small enough to prevent blocking the print heads of the inkjet printers. Likewise, all these inks have viscosities suitable for application by means of inkjet printers.
However, these inks have the drawback that the deposition rate resulting from their composition is very high, which prevents their permanency inside the printing machine with the printing being stopped for relatively short time periods, since the heads are obstructed due to the deposition of said inks.
Another additional problem is the fast drying of the ink because the drying rate of the inks with the known compositions is also very high. The drying of the ink in the groove of the print heads in short time generates a layer that tends to obstruct the print holes housed in said grooves, causing printing defects.
The objective of the present invention is to provide an ink the deposition and drying rates of which allow its permanency in the printing machine with the printing function being stopped for relatively long time periods and without obstructing the heads and also to prevent generating a layer that tends to obstruct the print holes housed in the grooves of the print heads, causing printing defects on the surface of the non-porous substrates to be decorated.
The present invention relates to an ink composition for non-porous surfaces including an organic solvent, ceramic pigments and a glass frit. As a solvent, an organic solvent is used as a vehicle which is liquid at room temperature and is made up of linear or non-linear n-alkane hydrocarbons and which allows overcoming the drawbacks described in the state of the art.
The organic solvent is preferably made up of a mixture of C14 n-alkane and C15-C20 n-alkane hydrocarbons; or by a mixture of C14 n-alkane and C18 n-alkane hydrocarbons; or by a mixture of C14 n-alkane and C18 n-alkane hydrocarbons and naphthenic oil; or by a mixture of C14 n-alkane and C15-C20 n-alkane hydrocarbons and naphthenic oil; or by a mixture of C14 n-alkane, C18 n-alkane hydrocarbons and the linear C9-C11 n-alkane hydrocarbon; or by a mixture of C14 n-alkane hydrocarbons and linear C9-C11 n-alkane hydrocarbon; or by a mixture of n-alkane C14 and C18 n-alkane hydrocarbons and linear C9-C11 n-alkane hydrocarbon and naphthenic oil. The ink according to the invention is characterized in that it has a deposition rate less than 0.1% and also has a drying rate less than 2% for 10 minutes and less than 9% for 1 hour.
The deposition rate is determined with an optical analyzer for analyzing liquid dispersion stability and instability (Turbiscan or the like), and the results are expressed as % by weight of ink deposited in an hour. The measurement is taken after 3 days and the value is divided by 72 hours which are the amount of time in 3 days. In an ink according to the present invention, the deposition rate is less than 0.1% and will preferably be comprised between 0.013 and 0.06%.
On the other hand, to determine the drying rate, a specific amount of ink placed in a beaker is weighed by means of an electronic thermobalance and is kept at 30° C. Weighings are performed at 10 and 60 minutes in order to determine the amount of solvent that has evaporated in those time periods. The result is expressed as % by weight of solvent evaporated at 10 minutes and at 60 minutes. In an ink according to the present invention, the drying rate is less than 2% for 10 minutes and less than 10% for 1 hour and preferably, 8% for 1 hour and comprised between 0.5% and 1.5% for 10 minutes.
The percentage by weight of the linear or non-linear n-alkane hydrocarbon-based organic solvent is comprised between 35% and 55% of the total weight
The ink thus characterized allows significant cost savings firstly by improving printing quality, maintaining said quality uniform over time, and secondly by preventing part of the ink from being rendered useless as a result of fast deposition and/or drying.
Once suitable deposition and drying rates are achieved, an additional advantage is derived from the possibility of using the stand-by function of the printing machines, which allows reducing power consumption of said machines.
Another additional advantage results from the use of ceramic pigments and frits that are free of lead and other hazardous compounds, an efficient protection in relation to safety and environmental protection thus being achieved.
According to the invention, the ink composition is characterized in that the size of the submicrometric particles contained in both the ceramic pigments and the glass frit is less than 0.40 micrometers.
Likewise, the percentage by weight of the glass frit is comprised between 20% and 35% of the total weight and made up primarily of Si, B and Zn oxides and salts, or by Si, B, Bi and Zn oxides and salts. The specific composition of the glass frit is selected depending on the required characteristics, depending primarily on the desired acid and base resistance, on the required meting temperature and on the coefficient of expansion of the support.
In relation to the ceramic pigments used for obtaining the different colors or effects, it must be highlighted that the pigments are selected from simple oxides and/or mixed oxides and/or crystalline structures and that the percentage by weight of said ceramic pigments is comprised between 5% and 25% of the total weight. Furthermore, according to the invention the ink can comprise at least one drying and polarizing agent, generally a long-chain alcohol, with boiling point comprised between 150 and 220° C., the percentage by weight of which is less than 5% of the total weight.
Likewise and also according to the invention, the ink can comprise at least one binding agent, one dispersing agent or hyperdispersant, one thixotroping agent and/or one wetting agent or humectant.
Cellulose derivatives, rosin resins, ketone resins, polyamides, among others, are used as a binding agent provided that they are soluble and compatible with the liquid vehicle of the ink. Polyamide or a mixture of polyamide and cellulose derivatives (ethyl cellulose) is preferably used as a binding agent.
The dispersing agent is characterized by being formed preferably by carboxylic acid copolymers or hyperdispersants and/or polymeric fatty esters. Likewise, the ink can preferably include urea derivatives, with additions between 1 and 0.1%, as a thixotroping agent in its composition.
The wetting agent or humectant is preferably polyether-modified polydimethylsiloxane with additions between 1 and 0.05%, preferably between 0.5 and 0.05%. The ink according to the invention can comprise additional components typically selected from cross-linking agents, anti-foaming agents, rheological control agents, anti-corrosion agents, coalescing agents, pH control agents and biocides.
After printing, i.e., once the ink is applied on the non-porous substrate or substrates, the surfaces of said substrates are subjected to heat treatment. The heat treatment is necessary so that the ink adheres to the substrate and the end color is generated. The adherence that is achieved with the heat treatment is such that the decoration made with the inks is permanent and resistant to abrasion, cleaning agents, the elements, etc. In order to achieve said adherence, the heat treatment is preferably performed in temperatures in the order of 500° C.
To complete the description that is being made and for the purpose of aiding to better understand the features thereof, several embodiments of the inks for providing color designs according to the invention accompany the present specification.
All the indicated embodiments are provided in an illustrative and non-limiting way.
Three compositions of red ink according to the present invention are indicated in the table below, the ranges of the percentage by weight of the components used in each of the different compositions being indicated:
With said compositions, the red inks according to the invention have the following physical properties:
According to the invention, the previously characterized red inks can comprise at least the following agents of which the range of their composition by weight is indicated:
The red inks with the indicated components are prepared by means of conventional methods generally used in the industry.
Tow compositions of blue ink according to the present invention are indicated in the table below, the ranges of the percentage by weight of the components used in each of the different compositions being indicated:
With said compositions, the blue inks according to the invention have the following physical properties:
According to the invention, the previously characterized blue inks can comprise at least the following agents:
Likewise, the blue inks with the indicated components are prepared by means of conventional methods generally used in the industry.
Four compositions of black ink according to the present invention are indicated in the table below, the components used in each of the different compositions being indicated:
With said compositions, the black inks according to the invention have the following physical properties:
According to the invention, the previously characterized black inks can comprise at least the following agents:
0.1-1%
In this case, the black inks with the indicated components are also prepared by means of conventional methods generally used in the industry.
Two compositions of yellow ink according to the present invention are indicated in the table below, the components used in each of the different compositions being indicated:
With said compositions, the yellow inks according to the invention have the following physical properties:
According to the invention, the previously characterized yellow inks can comprise at least the following agents:
0.1-1%
The yellow inks with the indicated components are prepared by means of conventional methods generally used in the industry.
Four compositions of white ink according to the present invention are indicated in the table below, the components used in each of the different compositions being indicated:
With said compositions, the white inks according to the invention have the following physical properties:
According to the invention, the previously characterized white inks can comprise at least the following agents:
The white inks with the indicated components are prepared by means of conventional methods generally used in the industry.
Two compositions of green ink according to the present invention are indicated in the table below, the components used in each of the different compositions being indicated:
With said compositions, the green inks according to the invention have the following physical properties:
According to the invention, the previously characterized green inks can comprise at least the following agents:
The green inks with the indicated components are prepared by means of conventional methods generally used in the industry.
Two compositions of etching ink according to the present invention are indicated in the table below, the components used in each of the different compositions being indicated:
With said compositions, the etching inks according to the invention have the following physical properties:
According to the invention, the previously characterized etching inks can comprise at least the following agents:
The etching inks with the indicated components are prepared by means of conventional methods generally used in the industry.
| Number | Date | Country | Kind |
|---|---|---|---|
| P201230278 | Feb 2012 | ES | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/ES2013/070086 | 2/12/2013 | WO | 00 |
