JPS644550B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a water-based ink composition. Conventionally, water-based ink compositions used in inkjet, felt-tip pens, ballpoint pens, felt-tip pens, etc. have been designed to increase dye solubility to prevent clogging, or to increase moisture retention to prevent ink from drying out quickly. In order to, ethylene glycol,
Polyhydric alcohols such as propylene glycol and glycerin, polyglycols such as diethylene glycol, triethylene glycol and polyethylene glycol, and glycol ethers such as methyl cellosolve, methyl carbitol and methyl triglycol have been used. These solvents are characterized by being highly soluble in water and having a high boiling point.
The viscosity of the aqueous solution changes greatly depending on the temperature, and depending on the temperature used, there are problems such as smearing, blurring, and sticking to paper too much. The present invention was made to solve the problems of the conventional products as described above, and by containing a specific alkoxypropanediol or its oxyalkylene derivative, the viscosity changes little due to temperature, and therefore it can be used in different seasons and regions. The purpose of the present invention is to provide an aqueous ink composition that exhibits almost the same writing quality even when the ink composition changes, and that does not smear, blur, or stick to paper too much. The present invention is an aqueous ink composition characterized by containing an alkoxypropanediol represented by general formula (1) or an oxyalkylene derivative thereof. (However, R is an alkyl group having 1 to 4 carbon atoms,
AO is an oxyalkylene group having 2 or 3 carbon atoms,
a+b is 0-10. ) In general formula (1), examples of the alkyl group having 1 to 4 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, and tert-butyl group. Number 2
Examples of the oxyalkylene group of 3 include oxyethylene and oxypropylene. Each of these may be used alone or as a mixture of a plurality of them. The reason why the number of carbon atoms in the alkyl group represented by R is limited to 4 or less is that if it is 5 or more, the surface activity becomes strong, causing foaming that causes clogging and ink running out. a and b represent the average number of added moles of the oxyalkylene group represented by (AO), including the case where each is 0. That is, for the compound of general formula (1), an alkoxypropanediol to which no oxyalkylene is added may be used, but an alkylene oxide may be added to the alkoxypropanediol for the purpose of increasing the boiling point and flash point. In this case, the amount added needs to be 10 moles or less. The reasons are 10
This is because if the amount exceeds mol, the viscosity of the aqueous solution will vary greatly depending on the temperature. The aqueous ink composition of the present invention has the above general formula (1).
This is a composition in which an alkoxypropanediol or its oxyalkylene derivative represented by the formula is blended with a water-soluble dye. The amount of alkoxypropanediol or its oxyalkylene derivative used is 2 to 2.
It is 60% by weight. Further, as the dye, any water-soluble dye can be used. For example, direct dyes include CI Direct Black 19, 51, 108, 194,
Direct Blue 2, 93, 98 Direct Red 1, 17, 28, Direct Yellow 12, 24, CI Acid Black 2, 31, 52, Acid Blue 59, 93, 103, Acid Red 87,
92, 155, and basic dyes include CI Basic Black 2, 8, Basic Blue 3, 7, Basic Cred 18, 52, and the like. The aqueous ink composition of the present invention can also contain other additives such as stabilizers, bactericides, surface tension regulators, and the like. The present invention is applicable to aqueous ink compositions used for ink jets, felt-tip pens, ballpoint pens, felt pens, and other uses. As described above, the water-based ink composition of the present invention is
There is little change in viscosity due to temperature, and the feeling of use is consistent depending on the season and region.
It has the effect of not being too tight. Examples will be described below in further detail. Example 1 A 25% by weight aqueous solution of the compounds shown in Table 1 was prepared, and 0
Viscosity was measured in the range ~40°C. The results are shown in the graph of the drawing and in Table 2.

【table】

【table】

[Table] From the results shown in the drawings and Table 2, it is clear that the temperature change in the aqueous solution viscosity of the product of the present invention is small. Example 2 CI Direct Black 19 3.0% Compound No. 1 in Table 1 25.0 Ion-exchanged water 72.0 The above compositions were mixed at room temperature to obtain a black ink. As a comparative example, a black ink was prepared using glycerin instead of compound No. 1 in Table 1. The results of measuring the viscosity of the two types of ink obtained are as follows, and the change in viscosity of the ink according to the example was small. Furthermore, the ink of the example did not bleed or fade, and had an excellent writing feel. 0℃ viscosity (cSt)
Viscosity at 40℃ (cSt) Example 5.2
2.9 Comparative Example 5.6
1.3 Example 3 CI Acid Blue 93 2.0% Compound No. 5 in Table 1 22.0〃 Ion exchange water 76.0〃 The above composition and No. 5 in Table 1 as a comparative example
Two types of blue inks were obtained in the same manner as in the previous example, using polyethylene glycol (molecular weight 200) instead of the compound. The viscosity of the two types of ink is as shown below, and the change in viscosity of the ink according to the example was small. Further, the ink of the example did not bleed or fade, and had an excellent writing feel. 0℃ viscosity (cSt)
Viscosity at 40℃ (cSt) Example 4.8
2.8 Comparative example 5.8
1.5 Example 4 CI Basic Cred 52 1.0% Compound No. 6 in Table 1 20.0〃 Ion exchange water 79.0〃 The above composition and No. 6 in Table 1 as a comparative example
Two types of red inks were obtained in the same manner as in the previous example, using propylene glycol instead of the compound. The viscosities of the two types of red inks are as shown below, and the changes in viscosity of those according to the examples were small. Further, the ink of the example did not bleed or fade, and had an excellent writing feel. 0℃ viscosity (cSt)
Viscosity at 40℃ (cSt) Example 5.0
3.1 Comparative example 5.0
1.0

[Brief explanation of drawings]

The drawing is a graph showing the relationship between temperature and viscosity in Example 1.

Claims (1)

[Scope of Claims] 1. An aqueous ink composition characterized by containing an alkoxypropanediol represented by general formula (1) or an oxyalkylene derivative thereof. (However, R is an alkyl group having 1 to 4 carbon atoms,
AO is an oxyalkylene group having 2 or 3 carbon atoms,
a+b is 0-10. ) 2 R is a methyl group, an ethyl group, an n-propyl group,
Isopropyl group, n-butyl group, isobutyl group,
The aqueous ink composition according to claim 1, wherein the aqueous ink composition is one or more groups selected from and tertiary butyl groups. 3. The aqueous ink composition according to claim 1 or 2, wherein AO is one or more groups selected from oxyethylene and oxypropylene.