JP3318011B2 - Ink composition for printer ribbon and ink ribbon using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ribbon ink composition used for a cloth ribbon for an impact printer used as a printing device such as a computer and a word processor, and an ink ribbon using the same.

[0002]

2. Description of the Related Art In recent years, as a printing device such as a computer or a word processor, a so-called impact printer which drives a printing wire into an ink ribbon for printing has been widely used.

Conventionally, as an ink composition for an impact printer ribbon, a colorant such as a dye in which a coloring agent such as a dye is uniformly dissolved or dispersed in oils such as higher fatty acids, animal and vegetable oils, and mineral oils has been used. There has been a demand for a ribbon ink having a high printing density and a long printing density.

On the other hand, recently, the rationalization of office work, physical distribution management, and the like has progressed, and the optical character reading device (OCR) or the bar code recognition device has become widespread. Visual density), as well as 800
It has been required to have a sufficient density for light in the infrared region near nm.

In response to such demands, carbon black has been used as a very useful coloring agent.
The ink containing the carbon black has a drawback that the printing wire is significantly worn especially when used in an impact dot printer. In recent years, high-speed printing and high-quality printing have been demanded.Accordingly, in impact dot printers, wires have become thinner and lighter, and the diameter of the wires has been reduced to 0.2 mm. Than big cemented carbide,
In a situation where high-speed steel or the like having a low specific gravity is used, this wear is a very serious problem.

As a countermeasure, a dye-type ink in which an oil-soluble dye is dissolved or dispersed in an oil agent is used. However, since these dyes hardly absorb light in the near infrared region, they are applicable to OCR devices and the like. There was no one. Further, among these dye-type inks, those using a dye treated with a fatty acid such as oleic acid have a problem of wire corrosion caused by the acid group of the fatty acid.

For example, JP-A-2-251578 proposes an oil-based ink to which a material absorbing near-infrared rays is added, but such a material is generally expensive.
In addition, the visual density was not sufficient, so its use was limited.

In Japanese Patent Application Laid-Open No. 63-170481, an attempt is made to reduce the wear of a printing wire by using carbon black having a specific particle size or less. However, carbon black having such a small particle diameter has a remarkably large specific surface area, and its dispersion is extremely difficult. Further, even if the ink composition can be dispersed, the viscosity of the ink becomes high, and it is difficult to obtain an ink composition having excellent fluidity.

Further, the pigment re-aggregates during storage due to the instability of dispersion, and the desired print density cannot be obtained, or the agglomeration of carbon black accelerates the wear of the print wire. Was not practical, and was not practical.

Further, Japanese Patent Application Laid-Open Nos. 61-246083, 4-65278, 4-6527
No. 9 discloses an ink ribbon using an organic pigment, which has very little wear on a printing wire.

However, ink ribbons using these organic pigments do not have sufficient ink fluidity and storage stability.
The organic pigment concentration in the ink ribbon could not be increased.

On the other hand, as a technique for improving the dispersibility of a pigment, a method using various pigment dispersants has been conventionally proposed, and some of them have been put to practical use in the printing ink field. For example, Japanese Patent Publication No. 54-34009 discloses a polyester oligomer obtained by dehydrating and condensing a hydroxycarboxylic acid, and British Patent No. 1,373,660 discloses an amide of the polyester oligomer and an amine compound. Compounds obtained by chemical conversion have been proposed. Further, U.S. Pat. No. 4,224,212 describes a conjugate of a polyester oligomer and a polyalkyleneamine.

However, the inventors of the present invention have studied that when these conventional pigment dispersants are used as the dispersant for the carbon black having a small particle diameter or the organic pigment, which is the colorant of the ink composition for printer ribbons. ,
The following problems were found.

For example, in the case of the above-mentioned polyester oligomer or its amide compound, the dispersibility of the fine carbon black or the organic pigment is not sufficient. There is the problem of corrosion and U.S. Pat.
No. 4,212, the dispersant has a problem that the viscosity of the dispersion becomes unnecessarily high due to the use of an extremely high molecular weight polyalkyleneamine, and the desired fluidity cannot be obtained. There is.

The present inventors have already disclosed in Japanese Patent Application No. 3-172282 in order to solve the above-mentioned problem.
An ink composition for a printer ribbon using the dispersant of the present invention in fine carbon black having an average primary particle diameter of 20 μm or less has been proposed.

However, the ink composition for a printer ribbon using the dispersant of the present invention in a fine carbon black having an average primary particle diameter of 20 μm or less has good ink fluidity and storage stability, print density, and OCR suitability. However, there is still a problem in terms of print wire wear.

[0017]

SUMMARY OF THE INVENTION The present invention has been made to solve these problems of the prior art, and can disperse an organic pigment even when the concentration of the organic pigment becomes high. Very little wire wear and corrosion, high printing density, weather resistance of printing,
An object of the present invention is to provide an ink composition for a printer ribbon having excellent ink fluidity and storage stability.

[0018]

Means for Solving the Problems As a result of intensive studies, the present inventors have made the above-mentioned description by using a pigment dispersant having a specific structure as a dispersant for an organic pigment in an ink composition for a printer ribbon. The inventors have found that the problem can be solved, and have completed the present invention.

That is, the present invention relates to an ink composition for a printer ribbon (excluding carbon black) containing an organic pigment, a pigment dispersant and an oil agent as essential components, as a pigment dispersant represented by the following general formula [I] or [ [II] An ink composition for a printer ribbon, comprising a reaction product obtained by a reaction between the amine compound represented by the formula [II] and a polyester having a free carboxyl group.

[0020]

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(In the general formula [I] or [II], R
¹ , R ² , R ⁴ and R ⁵ each represent an alkylene group having 2 to 4 carbon atoms, R ³ represents an alkyl group having 1 to 4 carbon atoms, and n represents 1 to 4
Indicates an integer of 4. In the general formula [II], n is 2
More time is an integer, each R ⁴ may be an alkylene group of mutually different number of carbon atoms) The present invention relates to an organic face
Fee, graphite, pigment dispersing agents, Oite printer <br/> Ribon ink composition to oil as essential components, as a pigment dispersant,
The amine compound represented by the general formula [I] or [II]
Of Polyester with Polyester Having Free Carboxyl Group
There is provided a printer ribbon ink composition characterized that you containing the reaction product is fractionated by.

Further, the present invention provides an ink ribbon obtained by applying the ink composition for a printer ribbon to a ribbon cloth.

[0023]

Hereinafter, the ink composition for a printer ribbon of the present invention will be described in more detail.

First, as the organic pigment used in the present invention, phthalocyanine pigments, azo pigments, various lake pigments and the like which have been generally used in the past can be used.

The content of the organic pigment added to the ink composition for a printer ribbon is preferably 25 to 45% by weight,
If the content is less than 45% by weight, a sufficient print density cannot be obtained, while if the content exceeds 45% by weight, the problem that fluidity and storage stability are deteriorated becomes apparent.

If the OCR reading density is particularly required, it is preferable to use 5 to 10% by weight of graphite in the ink composition for a printer in addition to the organic pigment.
However, when graphite is used in combination, the content of the organic pigment added to the ink composition for a printer ribbon is 15 to 40.
It is preferable to set the weight%. Average particle size for graphite
Those having a size of 0.5 to 3 μm are preferably used.

The reaction product used as a pigment dispersant in the present invention is obtained by reacting the amine compound represented by the above general formula [I] or [II] with a polyester having a free carboxyl group. It is.

When n is 5 or more in the above formula [II], the viscosity of the ink becomes high, and it becomes difficult to apply the ink to the ribbon cloth.

Specific examples of the amine compound represented by the general formula [I] include methyliminobisethylamine and ethyliminobispropylamine, and specific examples of the amino compound represented by the general formula [II] are as follows. Examples include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, dipropylenetriamine, tripropylenetetramine, tetrapropylenepentamine, pentapropylenehexamine, and even dibutylenetriamine.

The polyester having a free carboxyl group is obtained by dehydration-condensation of a polybasic acid and a polyhydric alcohol, or obtained by dehydration-condensation of a fatty acid having a hydroxyl group. Especially 25-45
Those in the range described above can be preferably used.

If the acid value of the polyester is less than 20, the adsorptive power to the organic pigment surface is weakened, and the desired dispersing effect cannot be obtained. However, the dispersion stability becomes insufficient.

Examples of the polybasic acids which are materials for obtaining the polyester include succinic acid, adipic acid, azelaic acid, sebacic acid, 1,12-dodecanedicarboxylic acid,
Examples thereof include 2- or 1,4-cyclohexanedicarboxylic acid and terephthalic acid. Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, and propylene glycol.

Examples of the fatty acid having a hydroxyl group include ricinoleic acid, 12-hydroxystearic acid or castor oil fatty acid, and hydrogenated products thereof.

Among the above-mentioned polyesters, polyesters obtained by dehydration condensation of a fatty acid having a hydroxyl group are particularly preferred.

The reaction product used as a pigment dispersant in the present invention can be obtained by bonding the amine compound and a polyester having a free carboxyl group by an amidation reaction in a conventional manner. Is as follows.

[0036]

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[0037]

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(In the above formulas [III] and [IV],
R ¹ , R ² , R ³ , R ⁴ , R ⁵ and n are as defined above,

[0039]

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Wherein the general formula [III] is a reaction product in which a polyester chain is bonded to the amine compound of the general formula [I], and the general formula [IV] is a general formula [II]
Is a model formula showing a reaction product in which a polyester chain is bonded to an amine compound of formula (1).

In the above model formula, a polyester chain is bonded to every nitrogen atom. This is an ideal model, and although it depends on the reactivity of the amine compound or polyester, it has some amine value. Compounds also exist. Here, as the reaction product, the amine compound is reacted with the carboxyl group of the polyester.
Those obtained by reacting at a ratio of 0.8 to 1.0 equivalent are preferred. The weight average molecular weight of this reaction product is 20 ×
A range from 10 ^{2 to} 17 × 10 ³ is preferred.

The amount of the reaction product obtained by the above-mentioned reaction is preferably in the range of 10 to 50 parts by weight with respect to 100 parts by weight of the organic pigment. Can be determined as appropriate.

Other essential oils used in the ink composition for a printer ribbon include esters of fatty acids such as sebacic acid, oleic acid and linoleic acid.
Vegetable oils such as castor oil, safflower oil, rapeseed oil and soybean oil, mineral oils such as spindle oil and motor oil, and nonionic surfactants can be used alone or in combination.

Other components that can be used in the ink composition for a printer ribbon of the present invention include colorants such as oil-soluble dyes, surfactants, plasticizers, and various binder resins which have been conventionally used. Etc. can be used as needed.

The ink composition of the present invention is prepared by adding an organic pigment, the above-mentioned reaction product, and, if necessary, graphite and additives to the above oil agent, and mixing and kneading using various dispersers conventionally used. It can be obtained by meat.

In order to prepare an ink ribbon using the ink composition of the present invention, it can be obtained by coating a conventionally used cloth such as nylon with a conventionally known coating machine.

As described above, the ink composition for a printer ribbon of the present invention has excellent storage stability and fluidity even when the concentration of the organic pigment in the ink composition is high. By using the ink ribbon, it is possible to obtain an ink ribbon which does not corrode the printing wire and greatly reduces its abrasion. Further, when printing on paper or the like with this ink ribbon, a high printing density can be obtained.

[0048] The ink composition of the present invention will be specifically described with reference to the following examples, but the present invention is not limited to these examples unless departing from the gist and scope of the present invention. Unless otherwise specified, “parts”
Represents "parts by weight".

Synthesis Example of Dispersant A 12-hydroxystearic acid was dehydrated and condensed by a conventional esterification reaction to prepare a polyester having an acid value of 35. Amidation reaction was carried out on 100 parts of the polyester using 4.3 parts of methyliminobispropylamine, a compound corresponding to the compound of the formula [I] of the present invention, to give a reaction product A having a weight average molecular weight of 5,000. I got it. In the same manner, 100 parts of the polyester and 2.10 parts of triethylenetetramine corresponding to the compound of the general formula [II] of the present invention.
The reaction product was reacted with 5 parts to obtain a reaction product B having a weight average molecular weight of 7,300.

Examples 1 to 7 and Comparative Examples 1 to 4 Inks for ribbons were produced using each material according to the recipe shown in Table 1 and using a three-roll mill. As the organic pigment, a mixture of an azo-based orange pigment, a phthalocyanine blue pigment, and a methyl violet-based lake pigment was used. As the dispersant C, Solsperse S-17000 manufactured by ICI was used. As the oil agent, oleic acid was used. A mixture of 2-ethylhexyl ester and sorbitan surfactant was used.

The inks were evaluated for fluidity, storage stability, and corrosiveness to printing wires. In addition, 12g of these inks on 16mm wide nylon fabric
The ink ribbon coated so as to have a coating amount of / m ² was formed into a 60 m Mobius ring, which was loaded into a ribbon cassette.
Using this ribbon cassette, printing was performed with an impact dot printer, and the wear of the printing wire and the printing density were evaluated.

[Test Method] (1) Print Density After printing on ordinary white continuous paper using an impact dot printer, the A filter and the B filter were respectively attached using a densitometer PCM-II manufactured by Macbeth. hand,
The print density was measured.

(2) Abrasion Abrasion of the printing wire after printing 100 million dots was measured.

(3) Storage Stability The viscosity of the ink before storage and the viscosity of the ink after storage at 40 ° C. for 2 weeks were measured with a B-type viscometer, and the viscosity ratio represented by the following formula was determined. Sex was judged.

Viscosity ratio = viscosity of ink after storage for 2 weeks at 40 ° C./viscosity of ink before storage A: viscosity ratio ≦ 2 B: 2 <viscosity ratio ≦ 4 C: 4 <viscosity ratio (4) Corrosion The surface state when the printing wire was immersed in the ink at 85 ° C. for 72 hours was observed with an electron microscope, and the corrosion property was evaluated.

A: Almost no corrosion B: Slight corrosion is observed C: Extremely corrosion is observed (5) Fluidity It is determined whether the prepared ink has fluidity suitable for coating on a ribbon. It was judged.

A: Suitable for coating, good flowability B: Not suitable for coating, poor flowability

[0058]

[Table 1]

[0059]

The ink composition for a printer ribbon of the present invention has excellent storage stability and fluidity even when the concentration of the organic pigment in the ink composition is high. As a result, an ink ribbon that does not corrode the printing wire and greatly reduces its wear can be obtained. Further, when printing is performed on paper or the like with this ink ribbon, a high printing density can be obtained.

──────────────────────────────────────────────────続 き Continued on the front page (56) References JP 8-19351 (JP, B2) Patent 2997572 (JP, B2) Patent 2901352 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 11/00-11/20 B41J 31/00-35/08 B41K 1/48

Claims (5)

(57) [Claims] 1. A organic pigment, pigment dispersing agent, a printer ribbon ink composition to oil the essential components (where car
Bon black) , a reaction product obtained by a reaction between an amine compound represented by the following general formula [I] or [II] and a polyester having a free carboxyl group. Characteristic ink composition for printer ribbon. Embedded image (In the above general formula [I] or [II], R ¹ , R ² ,
R ⁴ and R ⁵ each represent an alkylene group having 2 to 4 carbon atoms, R ³ represents an alkyl group having 1 to 4 carbon atoms, and n represents an integer of 1 to 4. In the general formula [II], when n is an integer of 2 or more, each R ⁴ may be an alkylene group having a different number of carbon atoms.) 2. An organic pigment, graphite, a pigment dispersant, and an oil agent are required.
Placed in the printer ribbon for the ink composition to Sunari minutes
As a pigment dispersant, the following general formula [I] or [II]
Has a free carboxyl group with an amine compound represented by
The reaction product printer ribbon ink composition characterized that you containing for example by reaction with the polyester that. Embedded image (In the above general formula [I] or [II], R ¹ , R ² ,
R ^4, R ⁵ represents an alkylene group having 2 to 4 carbon atoms, R ³ is
Represents an alkyl group having 1 to 4 carbon atoms, and n is an integer of 1 to 4
Show. In the general formula [II], n is an integer of 2 or more.
, Each R ⁴ is an alkylene having a different carbon number from each other.
Group) 3. The ink composition for a printer ribbon according to claim 1, wherein the polyester is a polyester having an acid value of 20 to 60. 4. The ink composition for a printer ribbon according to claim 1, wherein the polyester is a polyester obtained by dehydrating and condensing 12-hydroxystearic acid. 5. An ink ribbon formed by applying the ink composition for a printer ribbon according to claim 1, 2, 3, or 4 to a ribbon material.