JP2002226748A - Pigment ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pigment ink composition capable of inhibiting bleeding without imparting pseudoplasticity to an ink, even though the composition exhibits a Newtonian viscosity behavior or a similar physical properties. SOLUTION: The pigment ink composition comprises a pigment and a dispersant and a mixed solvent comprising at least two solvents of different polarity which are each a poor solvent dissolving at most 0.5 wt.% of the dispersant when used alone but are a good solvent dissolving at least 0.5 wt.% of the dispersant in a mixed state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a writing instrument including a felt-tip pen, a ball-point pen and the like, a desk table, a vermilion table, a desk-top product including a penetrating mark using an open-cell material, and an office supply such as an ink jet and an ink ribbon. The present invention relates to a pigment ink composition used for related products.

[0002]

2. Description of the Related Art As means for suppressing bleeding of ink transferred onto paper or the like, conventionally, a pseudoplasticity imparting agent such as fine particle silica or bentonite is added as an ink composition to make the ink itself difficult to fluidize. And the method of suppressing the ink discharge amount. However, a decrease in the fluidity of the ink deteriorates the follow-up property at the time of ink discharge, the drying property on paper deteriorates, and the color density is reduced by suppressing the discharge amount, thereby impairing various physical properties. Become. There is also a means of suppressing bleeding by increasing the viscosity. However, not only does the fluidity of the ink deteriorate, but also the solid content in the ink composition increases, so that the stability of the ink also deteriorates.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems and the like, and is intended to solve such a problem. It is an object of the present invention to provide a pigment ink composition that suppresses bleeding on the paper surface even when the viscosity is a viscosity (even when the shear rate is changed and the viscosity is not affected by the shear rate and shows a constant value) or close to this. Aim.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies on the above-mentioned conventional problems and the like. As a result, the pigment ink composition does not dissolve the dispersant alone, and thus has a polarity which has not been conventionally used. By using two or more specific mixed solvents different from each other as the main solvent,
Finding that the above-mentioned pigment ink composition can be obtained,
The present invention has been completed. That is, the pigment ink composition of the present invention is a poor solvent in which the solubility of the pigment, the dispersant, and the dispersant alone is 0.5 wt% or less, but the solubility of the dispersant is 0.1% in a mixed state. It is characterized by containing at least two kinds of mixed solvents having different polarities, which are good solvents of 5 wt% or more.

The two kinds of mixed solvents of the present invention are represented by the following A
It is preferable to be selected from each of the group and the group B. Group A: a solvent in which the solubility of the dispersant is 0.5 wt% or less and which is higher in polarity than the solvent group in the polar range in which the dispersant can be dissolved. And a solvent which is lower in polarity than the solvent group in the polar range in which the dispersant can be dissolved, and which is uniformly mixed with the solvent selected in Group A.

In the above-mentioned pigment ink composition of the present invention, it is most preferable that the dispersant and the two kinds of mixed solvents are composed of the following combinations. Dispersant: polyvinyl butyral group A; · ethylene glycol · polyethylene glycol having 2 to 15 ethylene oxide · propylene glycol · monoester or diester of triol solvent such as glycerin B group · · polypropylene glycol having a molecular weight of 500 to 4000 · oleic acid And fatty acids such as stearic acid.-Among ethylene oxide-propylene oxide copolymerized diols, those in which the solubility of butyral resin is 0.5 wt% or less and which is liquid at normal temperature.-Alcohols having 4 or more carbon atoms. Further, the pigment ink composition of the present invention preferably has a Newtonian viscosity or a viscosity close to the Newtonian viscosity, since it has good fluidity and is easy to use.

[0007]

Embodiments of the present invention will be described below in detail. The pigment ink composition of the present invention uses a pigment as a colorant, and a dispersant for dispersing the pigment,
The solvent alone is a poor solvent in which the solubility of the dispersant is 0.5 wt% or less, but in the mixed state, the solubility of the dispersant is 0.1%.
It is characterized by comprising at least two kinds of mixed solvents having different polarities which are good solvents of 5 wt% or more.

First, mixed solvents having different polarities used in the present invention will be described. In general, when a certain substance (here, a pigment dispersant) is dissolved in a solvent, it is known that the two substances are easily dissolved if their polarities are close to each other. In the present invention, this solvent having good solubility (close to the polarity of the dispersant) is not used, and when the solvent is used alone, the solubility of the dispersant is poor. At least two kinds of mixed solvents having different polarities which are good solvents are used. In particular, it is preferable to use a mixture of a solvent having a higher polarity than a solvent group in a polarity range in which the dispersant to be used can be dissolved (that is, close to the polarity of the dispersant) and a solvent having a lower polarity. The substance having a high polarity is a substance having a large electron bias in the substance molecule, and examples thereof include water, glycerin, and glycol. Examples of the polar functional group include a hydroxyl group, an amino group, a nitro group, a nitrile group and the like, and a substance containing these groups generally has a high polarity.

Conversely, a substance having a low polarity is a substance such as a straight-chain hydrocarbon compound in which the electron bias in the molecule is small.
Materials containing large alkyl groups are generally less polar. However, in the present invention, the content that the polarity is high or low is a relative one. That is, a solvent capable of dissolving the dispersant (solvent group having a certain polarity range) is not used, and a solvent (group A) having a higher polarity than this solvent (solvent group) and a solvent having a lower polarity ( And a mixed solvent with (Group B).

Here, the reason why the dispersant is dissolved in the mixed solvent while the group A and the group B alone do not dissolve the dispersant and the ink can be formed is considered as follows. Usually, the dispersant contains a pigment-friendly functional group for adsorbing pigment and a solvent-friendly functional group for dissolution in a solvent.
Conceptually, the dispersant acts as a bridge between the pigment and the solvent. Therefore, a highly polar functional group and a low functional group are present in the dispersant molecule. In this case, the solvent A group alone acts on the highly polar functional group in the dispersant molecule, The low-polarity functional groups in the molecule of the dispersing agent do not act, and the low-polarity functional groups are aggregated with each other and cannot be uniformly dissolved. Conversely, the solvent B group alone acts on the low-polarity functional group in the dispersant molecule but does not act on the high-polarity functional group in the dispersant molecule, and the high-polarity functional groups aggregate. And cannot be uniformly dissolved.

However, in the case of the mixed solvent comprising the groups A and B of the present invention, the group A acts on the highly polar functional group in the molecule of the dispersant, and the group B acts on the less polar functional group. The dispersant dissolves uniformly. However, when the solvents of the groups A and B are not compatible with each other, the dispersant can only exist at the liquid-liquid interface of the groups A and B and eventually precipitates. Is an absolute condition. As described above, when the pigment enters the system in which the dispersant is uniformly dissolved, the solvent acting on the pigment palatability functional group in the dispersant is removed, and the dispersant (the pigment palatability functional group) Is exchanged and adsorbed to the pigment, and is stabilized as a pigment ink.

Therefore, in the present invention, these groups A and B are always used in combination, but two or more of groups A and B may be used in combination. The solubility of the dispersant in the groups A and B of the present invention can be determined under the following conditions. At a temperature of 60 ° C,
0.5 parts by mass of a dispersant is added to 99.5 parts by mass of the solvent, and the mixture is stirred for 2 hours and then left at room temperature for 1 day.
After standing, the dissolution state of the dispersant is visually checked. -When the solution is transparent; solubility exceeds 0.5 wt% (good solvent)
And -When the solution is cloudy or there is an undissolved substance;
5 wt% or less (poor solvent).

Here, the solvent of Group A used in the present invention may have a solubility of 0.5 wt.
% (Poor solvent) and a higher polarity than a group of solvents in a polar range in which the dispersant to be used can be dissolved. Examples include diols having two or more hydroxyl groups, polyols, and derivatives thereof. Specifically, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, glycerin, glyceryl monoacetate,
Glyceryl diacetate, glyceryl monobutyrate,
1,2,6-hexanetriol and the like. These are selected according to the type of dispersant used. In particular, when butyral resin is used as the dispersant, diethylene glycol, triethylene glycol, glyceryl monoacetate, and the like are preferable.

The solvent of Group B used in the present invention, when used alone, has a solubility of the dispersant of 0.5 wt% or less and is more polar than the solvent in the polar range in which the dispersant used can be dissolved. And has compatibility with the solvent selected from Group A. For example, polypropylene glycols, ethylene oxide / propylene oxide copolymerized diols, myristic acid, palmitic acid, stearic acid, isostearic acid, fatty acids such as oleic acid, n-
Alcohols having 4 or more carbon atoms such as butanol, 1-pentanol, n-hexanol, benzyl alcohol, n-octanol, n-decanol, cyclohexanol, methyl oleate, isobutyl oleate, lauryl oleate, isopropyl myristate, Fatty acid esters such as butyl stearate, isopropyl isostearate, ethyl benzoate, propyl benzoate, diisobutyl adipate, dibutyl oxalate, and dioctyl maleate are included.

These are selected according to the kind of the dispersant used. In particular, when polyvinyl butyral (butyral resin) is used as the dispersant, the molecular weight is 700.
Up to 2000 polypropylene glycol, ethylene oxide / propylene oxide copolymerized diols, isostearic acid, oleic acid, and the like can be suitably used. In the case of polypropylene glycol having a molecular weight of less than 700 (particularly, the number n of propylene oxide is in the range of 2 to 9), when the dispersant is a butyral resin, it cannot be used because it is a good solvent that dissolves more than 0.5 wt%. However, when the dispersing agent is other than butyral resin, it can be used if it is a poor solvent.

Solvent A used in the present invention that satisfies the above conditions
And the total amount of the solvent B (main solvent) is at least 50 wt% of the entire solvent (in the total amount of the solvent), preferably 80 to 100 watts.
If it is less than 50 wt%, the effect of suppressing bleeding is very poor. In addition, the solvent ratio of the groups A and B is not particularly limited, and is appropriately determined depending on the selected solvent and dispersant. Usually, the ratio (mass%) of solvent A / solvent B is 95/5 to 5/95, more preferably 85/1.
5 to 15/85. However, the group A and the group B alone have poor solubility of the dispersant and cannot disperse the pigment, and the pigment stability over time cannot be secured unless the solvents A and B are mixed. , Group A / group B = 0/100,
Or, a ratio of 100/0 is impossible. Further, the mixed solvent must have uniform compatibility. When the mixed solvent does not have uniform compatibility, the dispersion stability of the pigment ink is poor.

In addition, it is also possible to add a solvent (good solvent) that dissolves the dispersant to be used in an amount of 0.5 wt% or more as a secondary solvent. However, if the amount is large, the effect of suppressing bleeding is impaired. The amount is preferably set to 20% by weight or less of the total amount of the solvent. However, group A, B
It is limited to those compatible with the mixed solvent consisting of the group. Further, in the present invention, the total content of the solvents including the groups A and B varies depending on the dispersant, pigment, solvent type, and the like to be used, but is 30 to 99 wt% based on the total amount of the ink composition.
%, Preferably 40 to 90 wt%. When the total content of the solvent is less than 30% by weight based on the total amount of the ink composition, the fluidity of the ink becomes poor. And the like, which is unfavorable because it greatly affects the quality performance of the product such as color density and fixability.

The coloring agent used in the present invention is a pigment such as an organic pigment, an inorganic pigment, and colored resin particles.
And those which are difficult to dissolve in a solvent containing B and have an average particle diameter after dispersion of 30 nm to 700 nm by a dispersant. Specific examples include titanium oxide, carbon black, phthalocyanine, azo, dipyrrolopyrrole, anthraquinone, isoindoline, and quinacdrine. In addition, styrene, acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, acrylonitrile, resin emulsion obtained by polymerizing olefinic monomer, and hollow resin that swells in ink and becomes amorphous Emulsions or organic multicolor pigments composed of dyed resin particles obtained by dyeing the emulsions themselves with a coloring agent can also be used as the pigment in the present invention.

The coloring agent of the present invention may be used alone or in combination.
It can be used in a mixture of more than one species. If necessary, a dye can be added, but it has an adverse effect on bleeding, so it is necessary to keep the amount small. The content of the pigment is 0.5 to 30 wt%, preferably 5 to 20 wt%, based on the total amount of the ink composition. If the content of the pigment is less than 0.5 wt% with respect to the total amount of the ink composition, the color density of the product will be low, and if it exceeds 30 wt%, it will be difficult to ensure the stability of the ink.

The dispersant used in the present invention is not particularly limited as long as it can disperse a pigment as a colorant. Specific examples include synthetic resins such as polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl butyral, polyvinyl ether, styrene-maleic acid copolymer, ketone resin, hydroxyethyl cellulose and derivatives thereof, and styrene-acrylic acid copolymer. Particularly preferred is polyvinyl butyral, which is suitable as an oily dispersant. The content of the dispersant is 0.1 to 20% by weight, preferably 0.5 to 10% by weight based on the total amount of the ink composition.
%. If the content of the dispersant is less than 0.1 wt%, the dispersion stability of the ink will be poor, and if it exceeds 20 wt%, the fluidity of the ink will be poor.

In addition, one or more resins can be added for the purpose of improving the adhesion to paper and adjusting the viscosity. The type and amount of the resin are appropriately used according to the purpose, and are not particularly limited as long as they do not impair the stability of the pigment ink. If the desired quality can be achieved with a dispersant or the like, there is no particular need to add. In addition, a surfactant, a preservative, a rust preventive, a dissolution aid, and the like may be added as needed as long as the stability of the pigment ink is not impaired.

The viscosity of the pigment ink composition of the present invention depends on the product to be used and is not particularly limited, but is generally in the range of 1 to 300,000 mPa.s. s (25 ° C.). However, in a writing instrument using a low-viscosity type ink, 1 to 100 mPa. s, 100 to 300,000 mP for writing instruments that use other viscosity ranges
a. s (25 ° C., using an E-type viscometer) is preferable. The same viscosity range can be used for desk products as long as the product performance can be exhibited.

For producing the pigment ink composition of the present invention, conventionally known various methods can be adopted. For example,
Compounding each of the above components, using a stirrer such as a dissolver,
It can be easily obtained by mixing and stirring, or after mixing and pulverizing with a ball mill, a roll mill, a bead mill, a sand mill or the like, and then removing the coarse particles of the pigment, undissolved matter, and mixed solid matter by centrifugation or filtration.

In the pigment ink composition of the present invention, the Newtonian viscosity (even when the shear rate is changed, the viscosity is constant without being affected by the shear rate) can be attained even if the fluidity is not reduced by adding pseudoplasticity to the ink. Value) or bleeding can be suppressed in a state close to this. As a simple method of measuring the Newtonian viscosity, a viscosity is measured at different rotational speeds (shear speeds) using a rotational viscometer, and when the ratio (TI value) is taken, naturally, if it is 1, a new viscosity is used. It's Tonian. In the technical field of the present invention, ink having Newtonian viscosity is
There is a merit that it is easy to use because of good fluidity.

In addition, the ink has an effect of clearly suppressing bleeding even when compared with ink using a solvent that dissolves a dispersant.
It is not clear why such an effect is exhibited, but it has been found that the larger the difference in solvent polarity between the groups A and B used, the greater the effect of suppressing bleeding. Due to the difference in solvent diffusion caused by the ink, the solvent balance of the ink is lost, the ink becomes unstable rapidly,
It is presumed that the aggregation of the solid content on the paper surface rapidly progresses, thereby exerting the effect of suppressing bleeding.

[0026]

Next, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the following examples. The following "wt%" means mass%. The pigment ink composition prepared in each of the following examples was filled in a vermilion stand container, and the following test contents were evaluated.

(1) Viscosity Measurement is carried out with an E-type viscometer under the following conditions. Temperature: 25 ° C., number of revolutions: 10 rpm, (2) rheological characteristics (TI value) E-type viscometer similar to the item (1), number of revolutions: 2.5 rpm
The viscosity is measured at 10 and 10 rpm, and pseudoplasticity is evaluated from the value obtained by the following calculation formula. TI value = (viscosity at 2.5 rpm) / (viscosity at 10 rpm) If the TI value is close to 1, it is Newtonian, and as it increases from 1, the ink becomes pseudoplastic. (3) Bleeding property Printed on a commercially available tracing paper, 25 ° C, humidity 60
After storage for one week under the% condition, the degree of bleeding is visually evaluated according to the following criteria.・ Bleeding degree: (excellent) ◎>>□>△> × (poor)

Example 1 Solvent (Group A) α-monoacetin 25 wt% (Group B) Polypropylene glycol (molecular weight 1000) 58 wt% (Uniol D-1000: manufactured by NOF Corporation) Dispersant Polyvinyl butyral 3 wt% (Eslek B BM-1 : Sekisui Chemical) Pigment (Fuji Fast Red # 1010: Fuji Dye) 14wt%

Example 2 Solvent (Group A) Diethylene glycol 8 wt% (Group B) Ethylene oxide / propylene oxide copolymerized diol (Pronone 102: manufactured by NOF Corporation) 74 wt% Dispersant Polyvinyl butyral 4 wt% (Eslek B BM-1: Sekisui Chemical Pigment (Irgazine DPP Scarlet EK: Ciba-Geigy) 14wt%

Example 3 Solvent (Group A) α-monoacetin 25 wt% (Group B) Polypropylene glycol (molecular weight 1000) 58 wt% (Uniol D-1000: manufactured by NOF CORPORATION) Dispersant Polyvinyl butyral 3 wt% (Eslek B BM-1 : Sekisui Chemical) Pigment (Irgajin Red # 2031: Ciba-Geigy) 14wt%

Example 4 Solvent (Group A) Triethylene glycol 8 wt% (Group B) Ethylene oxide / propylene oxide copolymerized diol (Pronone 104: manufactured by NOF Corporation) 74 wt% Dispersant Polyvinyl butyral 4 wt% (Eslek B BM-1: Sekisui Chemical) Pigment (Irgazine DPP Scarlet EK: Ciba-Geigy) 14wt%

Comparative Example 1 Solvent (Good Solvent) Polypropylene Glycol (Molecular Weight 400) 85 wt% (Uniol D-400: Nippon Yushi) Dispersant Polyvinyl Butyral 5 wt% (Eslek B BM-1: Sekisui Chemical) Pigment (Irgazine DPP) Scarlet EK: Ciba-Geigy) 10wt%

Comparative Example 2 Solvent (Good Solvent) Polypropylene Glycol (Molecular Weight 400) 85 wt% (Uniol D-400: Nippon Yushi) Dispersant Polyvinyl Butyral 5 wt% (Eslek B BM-1: Sekisui Chemical) Pigment (Fujifast) Red # 1010: Fuji dye) 10wt%

Comparative Example 3 Solvent (Good Solvent) Propylene Glycol Monolysylate 82 wt% (PGMR: manufactured by Ito Oil) Dispersant Polyvinyl Butyral 4 wt% (Eslek B BM-1: manufactured by Sekisui Chemical) Pigment (Irgazine DPP Scarlet EK: Ciba Geigy) 14wt%

Comparative Example 4 Solvent (good solvent) Polypropylene glycol (molecular weight: 400) 65 wt% (Uniol D-400: manufactured by NOF) Solvent (poor solvent): polyethylene glycol 20 wt% (PEG # 200: manufactured by NOF Dispersant polyvinyl butyral) 5 wt% (ESREC B BM-1: Sekisui Chemical) Pigment (Fuji Fast Red # 1010: Fuji dye) 10 wt%

Comparative Example 5 Solvent (Good Solvent) Polypropylene Glycol (Molecular Weight 400) 45 wt% (Uniol D-400: manufactured by NOF) Solvent (Poor Solvent) Polypropylene glycol (molecular weight 1000) 40 wt% (Uniol D-1000: Nippon Oil and Fat) 5% by weight of dispersant polyvinyl butyral (Eslek B BM-1: Sekisui Chemical) 10% by weight of pigment (Irgazine DPP Scarlet EK: Ciba-Geigy)

Comparative Example 6 Solvent (Good Solvent) Polypropylene Glycol (Molecular Weight 400) 85 wt% (Uniol D-400: Nippon Yushi) Dispersant Polyvinyl Butyral 3 wt% (Eslek B BM-1: Sekisui Chemical) Pigment (Fujifast) Red # 1010: Fuji Dye) 10 wt% Pseudoplasticity imparting agent (Aerosil # 380: Nippon Aerosil) 2 wt%

Comparative Example 7 Solvent (Group A) α-monoacetin 87 wt% Dispersant Polyvinyl butyral 3 wt% (Esrec B BM-1: manufactured by Sekisui Chemical) Pigment (Fuji Fast Red # 1010: manufactured by Fuji Dye) 10 wt%

Comparative Example 8 Solvent (Group B) Polypropylene Glycol (Molecular Weight 1000) 87 wt% (Uniol D-1000: Nippon Yushi) Dispersant Polyvinyl Butyral 3 wt% (Eslek B BM-1: Sekisui Chemical) Pigment (Fujifast) Red # 1010: Fuji dye) 10wt%

A pigment ink composition was obtained by dispersing with a roll mill using the compositions of Examples 1 to 4 and Comparative Examples 1 to 8. However, in Comparative Examples 7 and 8, (Group A)
Even when the ink was prepared in each of the single solvents of (Group B), gelation or coagulated sediment was generated, and the ink itself did not have any stability, and "ink formation was impossible". Comparative Example 7
Table 1 shows the results obtained by measuring the viscosity, rheological properties (TI value), and bleedability of the above-described test contents as dispersants for each of the samples other than Samples 8 and 8. In addition, Table 1 shows the bleeding state of imprints obtained by filling each pigment ink composition into a vermilion container and stamping it with [Mitsubishi] three times using a commercially available seal.

[0041]

[Table 1]

As shown in Table 1, in Examples 1 to 4, there was almost no bleeding even in a state close to the Newtonian viscosity, whereas in Comparative Examples 1 to 5, it was equal to or more than that of the example. Even if the viscosity is high, bleeding is large. In Comparative Example 6, there is almost no bleeding, which is due to the pseudoplasticity of the ink. As described above, in Examples 1 to 4, there was almost no bleeding even in a state close to the Newtonian viscosity, whereas in Comparative Examples 1 to 6, bleeding was large, or finally, by giving pseudoplasticity. It can suppress bleeding, and is clearly inferior to the examples.

[0043]

According to the present invention, for a pigment ink used for a desk product such as a writing implement or a seal product, a pseudo ink is prepared by mixing two or more solvents having different polarities each having a poor solubility of a dispersant alone. There is provided an excellent pigment ink composition which can suppress bleeding on paper with a viscosity close to Newtonian without imparting plasticity. In addition, it has long-term storage stability by suppressing undesired phenomena such as sedimentation of pigment, separation of main solvent and dispersion, and extreme increase in viscosity. It can be suitably used for desk-top products including a perfume stamp using a vermicelli, a continuous foam material, and office supply-related products such as OA ribbons and inkjet printers.

Claims (4)

[Claims] 1. A poor solvent having a solubility of 0.5 wt% or less in a pigment and a dispersant, and a dispersant alone having a solubility of 0.5 wt% or less in a mixed state. A pigment ink composition comprising at least two types of mixed solvents having different polarities. 2. The pigment ink composition according to claim 1, wherein the two types of mixed solvents are selected from each of the following groups A and B. Group A: a solvent in which the solubility of the dispersant is 0.5 wt% or less and which is more polar than the solvent group in the polar range in which the dispersant can be dissolved. Group B: the solubility of the dispersant is 0.5 wt% or less. And a solvent which is lower in polarity than the solvent group in the polarity range in which the dispersant can be dissolved, and which is uniformly mixed with the solvent selected in Group A. 3. The pigment ink composition according to claim 1, wherein the dispersant and the two kinds of mixed solvents comprise the following. Dispersant: polyvinyl butyral group A; · ethylene glycol · polyethylene glycol having 2 to 15 ethylene oxide · propylene glycol · monoester or diester of triol solvent such as glycerin B group · · polypropylene glycol having a molecular weight of 500 to 4000 · oleic acid And fatty acids such as stearic acid, etc. Among ethylene oxide-propylene oxide copolymerized diols, those in which the solubility of butyral resin is 0.5 wt% or less and which is liquid at ordinary temperature ・ Alcohols having 4 or more carbon atoms 4. The pigment ink composition according to claim 1, which has a Newtonian viscosity or a viscosity close thereto.