JPH10279863A - Hot melt type solid ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color change after storage at 125 ° C. for 10 days which is used for recording by heating and melting to a temperature higher than room temperature in an ink jet recording apparatus.
Provided is a hot melt type solid ink having E of 5 or less. A hot-melt solid ink containing a wax, a coloring material, and a polyamide resin having an amine value of 2 or less and an amine value + acid value of 8 or less. Hot melt type solid ink containing wax, coloring material, polyamide resin and high molecular weight phenolic antioxidant. A hot melt solid ink containing a wax, a coloring material, a polyamide resin having an amine value of 2 or less and an amine value + acid value of 8 or less, and a high-molecular phenolic antioxidant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state hot-melt ink at room temperature, that is, a so-called hot melt solid ink. More specifically, the present invention relates to a hot-melt solid ink having a small color change due to heat preservation, which is used for recording by being heated and melted to a temperature higher than room temperature in an ink jet recording apparatus.

[0002]

2. Description of the Related Art In a conventional ink jet recording system, an aqueous ink using water as a main solvent and an oil-based ink using an organic solvent as a main solvent are generally used. Printed images using water-based inks generally have poor water resistance, whereas oil-based inks can provide printed images having excellent water resistance.

However, these water-based and oil-based inks are liquid at room temperature, and when printed on recording paper, penetrate rapidly because they penetrate rapidly, making it difficult to obtain a sufficient print density. Furthermore, since the ink is always liquid, precipitates such as dye aggregates are likely to be generated from the ink during storage, and these deposits block the ink flow path and the discharge port, and the reliability of the ink jet recording system. Was greatly reduced.

For the purpose of remedying the drawbacks of these conventional solution-type inks, so-called hot-melt type oil-based inks for ink-jet recording have been proposed, which use inks which are solid at normal temperature and melt by heating. Specifically, US Pat. No. 3,653,932 discloses an ink containing a dialkyl sebacate,
U.S. Pat. No. 4,390,369 and JP-A-58-1
No. 08271, an ink containing a natural wax, Japanese Patent Application Laid-Open No. 59-22973, an ink containing a stearic acid, Japanese Patent Application Laid-Open No. 61-83268.
JP-A-62-48774 discloses an ink containing an acid or alcohol having 20 to 24 carbon atoms and further containing a ketone having a relatively high melting point. A thermosetting resin having, a solid organic solvent having a melting point higher than 150 ° C.,
Ink containing a small amount of dye substance
In JP-A-27, a coloring material, a first solvent which is solid at room temperature and liquefies when heated to a temperature higher than room temperature,
JP-A-62-295973 discloses an ink comprising a second solvent which is liquid at room temperature and has a high volatility, which dissolves a solvent of the formula (1), wherein a synthetic wax having a polar group and a dye soluble in the wax are used. Included inks and the like have been proposed.

[0005] These hot-melt type solid inks are mounted on a hot-melt ink-jet recording apparatus, turned into a liquid state by heating, discharged from a discharge mechanism in a liquid state, and printed and printed on a print medium. However, conventional hot-melt type solid inks, when left in a molten state for a long time, discolor the ink itself, especially in the case of vividly colored color inks, the color darkens, and the initial vividness However, there has been a problem that a stable color cannot be maintained and thermal stability is poor. Such problems tended to be more severe as the melting temperature was higher and as the time being placed was longer.

In a hot-melt ink-jet recording system using a hot-melt type solid ink, it is desirable that the time from when a signal is sent at the time of printing until printing starts be as short as possible. Has become. Therefore, it is desirable that the ink be in a heated state even in a standby state of the ink jet printer, and that the ink be heated up to the ink discharge temperature since printing can be performed immediately when a signal is sent. However, placing a conventional hot-melt type solid ink for a long time while being heated to near the ejection temperature is difficult.
As described above, it is not desirable because the ink is easily discolored. For this reason, the conventional hot-melt type solid ink is set to a temperature lower than the discharge temperature in the standby state of the hot-melt inkjet printer, and the ink is heated to the discharge temperature from when a signal for printing is received to when printing is started. Must be heated up to
It was taking time.

[0007]

Accordingly, the inventions according to claims 1 and 2 of the present invention maintain basic performance and good printing quality as a hot-melt type solid ink for an ink jet printer, It is an object of the present invention to provide a hot-melt type solid ink which is stable and hardly discolors even if it is placed for a long time while being heated to a temperature close to the discharge temperature. The third aspect of the invention has the same purpose as the first and second aspects of the invention, but aims to provide a particularly suitable hot melt type solid ink.

[0008]

According to one aspect of the present invention, there is provided a hot-melt solid ink for an ink-jet printer which is solid at ordinary temperature and is used by melting after heating. ,wax,
Color material, amine value is 2 or less and amine value + acid value is 8
It is characterized by containing the following polyamide resin.

Here, when a general polyamide resin is used as the polyamide resin instead of a specific polyamide resin having an amine value of 2 or less and an amine value + acid value of 8 or less, the invention according to claim 2 is preferred. In addition, a high molecular weight phenolic antioxidant can also be used.

Further, when a hot-melt type solid ink having a small color change is particularly desired, a polyamide having an amine value of 2 or less and an amine value + acid value of 8 or less as described in the third aspect of the present invention. Both a resin and a high molecular weight phenolic antioxidant can be used.

[0011] Among the vehicles used in the present invention, polyamide resins are relatively unstable to heat, and are considered to be oxidized and discolored when placed at a temperature as high as the melting temperature for a long time. However, when a specific polyamide resin having an amine value of 2 or less and an amine value + acid value of 8 or less is used as the polyamide resin, the hot-melt solid ink is stable against heat, The color change due to is small. In addition, in a hot-melt solid ink containing a polyamide resin, a color change due to heat storage can be suppressed particularly by including a polymer phenolic antioxidant. In addition, even when a high-molecular-weight phenolic antioxidant is used, since it has good compatibility with other vehicles, it imparts the action of the polyamide resin, that is, the adhesion of the ink to printing paper. However, it does not hinder the action of preventing crystallization of the wax, imparting transparency to the ink, and the like, and does not hinder the action of the wax, that is, imparting thermal properties and viscosity to the ink. Therefore, the addition of the phenolic antioxidant does not impair the basic performance of the ink (transparency of the ink, clearness of the color, etc.) and good print quality.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The polyamide resin used in the present invention is obtained by condensation polymerization of an amine and an acid. As the amine, for example, hexamethylenediamine can be used. For example, adipic acid, sebacic acid, trimellitic anhydride, dimer acid and the like can be used.Furthermore, those having both an amine and an acid include 11-aminoundecanoic acid, 12-aminododecanoic acid and the like. By combining
A polyamide resin having desired characteristics (amine value, acid value) can be adjusted. Specific examples of commercially available polyamide resins that can be used in the present invention include, for example, the following: Tomide 90, Tomide 9
2, tomide 391, tomide 394, tomide 394N, tomide 395, tomide 397, tomide 509, tomide 535, tomide 558,
Tomide 560, Tomide 575, Tomide 13
10, Tomide 1350 (all manufactured by Fuji Kasei), Polyimide S-40HA, Polymide S-40E, Polymide S-150, Polymide S-52, Polymide S-
185, Polyimide S-1510, Polyimide S-15
25, Polyimide S-1635, Polyimide S-196
2, Polyimide S-2007, Polyimide S-2153
(Manufactured by Sanyo Chemical Co., Ltd.), Versamide 335, Versamide 725, Versamide 744, Versamide 756, Versamide 930, Versamide 940 (Henkel Hakusui) and the like. In the present invention, these may be used alone or in a mixture of two or more.

The amine value and the acid value of the polyamide resin are determined by titration with an aqueous hydrochloric acid solution and an aqueous potassium hydroxide solution according to a standard test method. The amine value used in the present invention is 2 or less and the amine value + acid value is 8
The following polyamide resin can be determined according to such a standard test method. In the present invention, it is more preferable to use a polyamide resin having an amine value of 2 or less and an amine value + acid value of 6.5 or less. As described above, such a polyamide resin can be adjusted to a desired amine value and acid value by appropriately selecting the amines and acids.

In the present invention, the total amount of the polyamide resin is 5 to 5 based on the total weight of the ink.
It is used in such an amount as to be in the range of 50% by weight. If the content of the polyamide resin in the ink is less than 5% by weight, not only the melt viscosity sufficient for discharging by the ink jet recording method is not obtained, but also the transparency of the ink and the adhesiveness to the printing medium are reduced. I can't get it. On the other hand, if the content of the polyamide resin in the ink is more than 50% by weight, the melt viscosity of the ink becomes too high, so that it is difficult to discharge the ink at a good operating temperature of the printer head used for inkjet recording. At the same time, the penetration of the ink into the paper when attached to paper or the like becomes worse, and if the printing surface is rubbed with a hand or the like, the ink is peeled off from the paper or the like, so that good printing quality cannot be maintained. . Therefore, the total amount of the polyamide resin is preferably contained in the ink in the range of 10 to 30% by weight.

In the present invention, a wax having a melting point of 50 ° C. to 200 ° C. and being stable to heat is used. Specifically, petroleum wax, desirably paraffin wax or microcrystalline wax, vegetable wax, desirably candelilla wax, carnauba wax, rice wax, or jojoba solid wax, animal wax, desirably beeswax, lanolin Or whale wax, mineral wax, preferably montan wax, synthetic hydrocarbon, preferably Fischer-Tropsch wax or polyethylene wax, hydrogenated wax, preferably hydrogenated castor oil or hydrogenated castor oil derivative, modified wax, preferably Montane wax derivatives, paraffin wax derivatives, microcrystalline wax derivatives or polyethylene wax derivatives, and synthetic fats and oils such as higher fatty acids, preferably behenic acid and stearic acid Palmitic acid, myristic acid,
Or lauric acid, a ketone wax, desirably distearyl ketone, a higher alcohol, desirably stearyl alcohol, or behenyl alcohol, hydroxystearic acid, desirably 12-hydroxystearic acid or a 12-hydroxystearic acid derivative, or laurin as a fatty acid amide Acid amide, stearic acid amide, oleic acid amide, erucic acid amide, ricinoleic acid amide, stearic acid ester amide, palmitic acid amide, behenic acid amide, brassic acid amide, N-oleyl stearic acid amide, N-stearyl stearic acid amide, N-oleyl palmitic acid amide, N-stearyl erucic acid amide and the like can be mentioned. Also ketone,
Desirably stearone or laurone, amine, preferably dodecylamine, tetradecylamine or octadecylamine, or ester, preferably methyl stearate, octadecyl stearate, glycerin fatty acid ester, sorbitan fatty acid ester, propylene glycol fatty acid ester, ethylene glycol fatty acid Any known wax such as an ester or a polyoxyethylene fatty acid ester, a polymerized wax, preferably an α-olefin maleic anhydride copolymer wax can be used without particular limitation. These waxes can be used alone or in combination of two or more.

The above-mentioned wax is used in such an amount that the total amount of the wax is in the range of 20 to 90% by weight based on the total weight of the ink. If the content of the wax in the ink is less than 20% by weight, the ink will not have sufficient transparency, and the characteristics of other additives will appear, so that the melting point of the ink will increase or become unstable. Thus, the ink does not melt sharply at the inkjet discharge temperature. On the other hand, when the content is more than 90% by weight, a melt viscosity sufficient to function as an ink cannot be obtained, and the ink hardly adheres to printing paper.

In order to suppress the color change of the hot melt type solid ink of the present invention due to heat storage, it is effective to use a high molecular weight phenolic antioxidant and a high molecular weight hindered phenolic antioxidant. It is preferable to use an agent. As specific examples of such an antioxidant, for example,
1,1,3-tris (2-methyl-4-hydroxy-5
-Tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4)
-Hydroxybenzyl) benzene, tetrakis- [methylene-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionate] methane, bis [3
3′-bis- (4′-hydroxy-3′-tert-butylphenyl) butyric acid] glycol ester,
1,3,5-tris (3 ′, 5′-di-t-butyl-
4'-hydroxybenzyl) -S-triazine-2,
4,6- (1H, 3H, 5H) trione, tocopherols, 3,9-bis [1,1-dimethyl-2- [β-
(3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl] 2,4,8,10-
And tetraoxaspiro [5,5] undecane. In the present invention, these may be used alone or in a mixture of two or more.

In the present invention, the total amount of the high molecular weight phenolic antioxidant is in the range of 0.1 to 5.0% by weight based on the total weight of the ink. Use in such amounts. If the content of the high molecular weight phenolic antioxidant in the ink is less than 0.1% by weight, sufficient effects such as easy discoloration of the ink in a heated and melted state are not exhibited, and 5.0% by weight. If more than
The original performance of the ink cannot be exhibited, such as an increase in the melt viscosity that is inappropriate for use as a hot melt ink.

As the coloring material used in the present invention, any of dyes and pigments conventionally used in oil-based ink compositions can be used. Pigments that are generally used in the technical field of printing, whether organic or inorganic, can be used. Specifically, for example, carbon black, cadmium red, molybdenum red, chrome yellow,
Cadmium yellow, titanium yellow, chromium oxide, viridian, titanium cobalt green, ultramarine blue, Prussian blue, cobalt blue, azo pigment, phthalocyanine pigment, quinacridone pigment, isoindolinone pigment, dioxazine pigment, sulene pigment Conventionally known pigments such as perylene-based pigments, perinone-based pigments, thioindigo-based pigments, quinophthalone-based pigments, metal complex pigments, etc., are particularly limited as long as the primary particle size is in the range of 10 to 100 nm. It can be used without. These pigments can be used in combination. Dyes can be used any of dyes conventionally used in oil-based ink compositions, but azo dyes, disazo dyes, metal complex dyes, naphthol dyes, anthraquinone dyes, indigo dyes, carbonium dyes,
Oil-soluble dyes such as quinone imine dyes, cyanine dyes, quinoline dyes, nitro dyes, nitroso dyes, benzoquinone dyes, naphthoquinone dyes, xanthene dyes, phthalocyanine dyes and metal phthalocyanine dyes are preferred. These dyes can be used in combination. In the present invention, both a dye and a pigment can be used as the coloring material, but it is desirable to use a soluble dye having excellent heat stability and solubility with other vehicles. In order for the ink to have sufficient color-forming ability, these coloring materials may be added in the ink in an amount of 0.1%.
It is preferably contained in an amount of from 1 to 10% by weight, and preferably from 0.5 to 8% by weight in consideration of the color developing ability when printing with a printer. Further, as a guarantee that the pigment does not agglomerate, the content is more preferably 1 to 5% by weight.

The vehicle used in the present invention described above,
When using other vehicles or additives, they are all solid at room temperature, so that when preparing the hot melt type solid ink of the present invention, they are all melted at a temperature higher than the melting temperature, It is necessary to mix and disperse well, and if such an object can be achieved, the means for preparing the hot melt type solid ink of the present invention is not limited at all, and any means can be used. Good. The procedure for producing the hot melt type solid ink of the present invention will be described below. Each of the vehicles used in the present invention at the above-described ratio, and when other vehicles or additives are used, they are contained in a container at a ratio within a range not to impair the performance of the hot melt type solid ink of the present invention. The temperature is higher than the highest melting temperature among the melting temperatures of the charged and vehicle, additives when used, usually 70 ° to 250 ° C, preferably 100 ° to 20 ° C.
The mixture is heated and melted at a temperature of about 0 ° C., and then a coloring material is loaded. Once the vehicle, additives if used, etc. have been melted, the agitator is rotated at a speed and time sufficient to obtain a uniform mixture, typically at 200 to 10,000 RPM, preferably 500 to 5,000 RPM, usually Enough to several hours,
Preferably, the mixture is rotated for about 1 to 2 hours to sufficiently stir and mix the mixture. The stirring and mixing are performed until one drop of the mixture is taken on a slide glass and the absence of aggregates is confirmed by an optical microscope (about 200 times). After the completion of the stirring and mixing, the obtained mixture is subjected to filtration in a molten state through a filtration device to filter heterogeneous substances, and the substances that have passed through the filter are obtained as final hot-melt solid ink.

[0021]

EXAMPLES Specific examples are given below to illustrate the present invention. Example 1 An amine and an acid were polycondensed to prepare a polyamide resin having an amine value of 1.8 and an amine value + acid value of 4.9. This polyamide resin and ketone wax T-1 (manufactured by Kao Soap Co., Ltd.) as a wax were charged into the apparatus in the following amounts, and heated and melted at a temperature of 130 ° C.
eopen Yellow 075 (manufactured by BASF) was loaded. 1,000 RPM with dissolver
For about 1 hour. One drop of the mixture was taken on a slide glass, and it was confirmed by an optical microscope (200 times) that there was no aggregate. The obtained mixture was filtered with a 0.8 μm glass fiber filter G using a heating filter manufactured by Toyo Roshi Kaisha.
Filtration was performed using A200 (manufactured by Toyo Roshi Kaisha, Ltd.), and the mixture that passed through the filter was obtained as a hot-melt solid ink.

Polyamide resin 35 parts by weight T-1 62 parts by weight Neopen Yellow 075 3 parts by weight

The obtained hot-melt type solid ink was mixed with 11
Melted on a hot plate heated to 0 ° C., and used as an OHP (overhead projector) sheet (PP-2500,
(Sumitomo 3M) was coated with a winding rod (winding diameter 0.9 mm), and the color was measured with a colorimeter made by Suga Test Instruments.
Furthermore, after leaving this hot-melt type solid ink in a container kept at 125 ° C. for 10 days, it was coated on an OHP in the same manner as described above, and the color was measured. The obtained color difference ΔE was 3.34.

Example 2 The same components as those described in Example 1 were used, except that a polyamide resin having an amine value of 1.3 and an amine value + acid value of 6.5 was used as the polyamide resin. Used in quantity,
In addition, according to the same procedure as described in Example 1, a hot melt type solid ink was obtained.

The color of the obtained hot melt type solid ink was measured according to the same procedure as that described in Example 1, and the color was compared with that of the initial state. The obtained color difference ΔE was 3.7.
It was 8.

Comparative Example 1 The same components as described in Example 1 were used except that the polyamide resin having an amine value of 2.4 and an amine value + acid value of 4.9 was used as the polyamide resin. Used in quantity,
In addition, according to the same procedure as described in Example 1, a hot melt type solid ink was obtained.

The color of the obtained hot melt type solid ink was measured according to the same procedure as described in Example 1, and the color was compared with that of the initial state. The obtained color difference ΔE was 5.7.
It was 4.

Comparative Example 2 The same components as those described in Example 1 were used except that the polyamide resin having an amine value of 1.1 and an amine value + an acid value of 10.9 was used as the polyamide resin. Using the same amounts and following the same procedure as described in Example 1.
A hot melt type solid ink was obtained.

The color of the obtained hot melt type solid ink was measured according to the same procedure as that described in Example 1, and the color was compared with that of the initial state. The obtained color difference ΔE is 7.7.
It was 4.

Example 3 A polyamide resin having an amine value of 2.4 and an acid value of 7.5 as a polyamide resin, ketone wax T-1 as a wax, and a high-molecular phenolic antioxidant as an inhibitor were used. Certain tetrakis- [methylene-3-
(3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionate] methane (Irganox 10
10 (manufactured by Nippon Ciba Geigy Co., Ltd.)) was loaded into the apparatus in the following amount, and heated and melted at a temperature of 130 ° C .;
Yellow 075 was loaded. This was stirred and mixed with a dissolver at 1,000 RPM for about 1 hour. One drop of the mixture was placed on a slide glass, and the light microscope (20
(0 times), it was confirmed that there was no aggregate. The resulting mixture was filtered with a 0.8 μm glass fiber filter GA200 (Toyo Roshi Kaisha Co., Ltd.) using a hot filtration device manufactured by Toyo Roshi Kaisha.
), And the mixture passed through the filter was obtained as a hot melt type solid ink.

Polyamide resin 35 parts by weight T-1 61 parts by weight Irganox 1010 1 part by weight Neopen Yellow 075 3 parts by weight

The color of the obtained hot melt type solid ink was measured according to the same procedure as described in Example 1, and the color was compared with that of the initial state. The obtained color difference ΔE was 4.1.
It was 8.

Comparative Example 3 As an antioxidant, a monophenolic antioxidant such as 2,6-di-tert-butyl-p-cresol (Sumilyzer-BHT (Sumitomo Chemical Co., Ltd.)) was used. A hot melt solid ink was obtained using the same components and in the same amounts as described in Example 3 and following the same procedure as described in Example 3.

The color of the obtained hot melt type solid ink was measured according to the same procedure as described in Example 1, and the color was compared with that of the initial state. The obtained color difference ΔE is 5.6.
Nine.

Comparative Example 4 As an antioxidant, a bisphenol-based antioxidant such as 4,4'-methylene-bis (2,6-di-t-butylphenol (Ionox220 (manufactured by Shell)) was used. Using the same ingredients and in the same amounts as described in Example 3,
In addition, a hot melt type solid ink was obtained according to the same procedure as described in Example 3.

The color of the obtained hot melt type solid ink was measured according to the same procedure as described in Example 1, and the color was compared with that of the initial state. The obtained color difference ΔE was 8.7.
It was 6.

Example 4 The same components as described in Example 3 were used except that the polyamide resin having an amine value of 1.8 and an amine value + acid value of 4.9 was used as the polyamide resin. Used in quantity,
In addition, a hot melt type solid ink was obtained according to the same procedure as described in Example 3.

The color of the obtained hot melt type solid ink was measured according to the same procedure as described in Example 1, and the color was compared with that of the initial state. The obtained color difference ΔE was 2.9.
It was 8.

As is clear from the above, the hot melt type solid inks obtained in Examples 1 to 4 were left at the melting temperature for a longer time than the hot melt type solid inks obtained in Comparative Examples 1 to 4. Even after this, a clear printed image with little discoloration, no color dullness was maintained.

[0040]

The invention according to claims 1 and 2 of the present invention retains basic performance and good printing quality as a hot-melt type solid ink for an ink jet printer, is particularly stable to heat, and has excellent discharge characteristics. Discoloration can be suppressed even if the device is left for a long time while being heated to near the temperature. Further, the inventions according to claims 3, 4 and 5 claim 1
Among the effects of the inventions described in (2) and (3), discoloration can be particularly suppressed.

Claims (5)

[Claims] 1. A color change after storage at 125 ° C. for 10 days, comprising a wax, a coloring material and a polyamide resin having an amine value of 2 or less and an amine value + acid value of 8 or less.
A hot melt solid ink in which E is 5 or less. 2. A hot-melt solid ink containing a wax, a coloring material, a polyamide resin and a high-molecular-weight phenolic antioxidant and having a color change ΔE of 5 or less after storage at 125 ° C. for 10 days. 3. After storing at 125 ° C. for 10 days, it contains a wax, a coloring material, a polyamide resin having an amine value of 2 or less and an amine value + acid value of 8 or less, and a high-molecular-weight phenolic antioxidant. A hot melt solid ink having a color change ΔE of 5 or less. 4. The hot melt solid ink according to claim 2, wherein the high molecular weight phenolic antioxidant is a high molecular weight hindered phenolic antioxidant. 5. The hot melt according to claim 2, wherein the high molecular weight phenolic antioxidant is present in an amount of 0.1 to 5.0% by weight based on the total weight of the ink. Type solid ink.