Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Patent
1997-06-30
1999-03-02
Merriam, Andrew E. C.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
523215, 523512, 523513, 524514, 524601, 524602, 106 3158, 106 3186, C08L 6700, C09D 1100
Patent
active
058772359
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an aqueous ink which is prevented from blurring on paper and provides prints having improved waterfastness and improved fixation. More particularly, the present invention relates to an aqueous ink useful for ink jet recording.
BACKGROUND OF THE INVENTION
Aqueous inks are frequently used as printing or writing inks for the ease of manufacture and handling. For example, with the recent development and spread of computers, printers have also been spreading, and aqueous inks are made frequently use of in such printers.
The inks for an ink jet printer, one of typical printers, usually comprise a water-soluble dye capable of dissolving in water so as to avoid clogging of nozzles with the ink. Inks comprising a water-soluble dye hardly obstruct the nozzles but, in turn, the resulting printed image has poor waterfastness.
Therefore, the composition of inks is of importance to improve waterfastness of printed images.
In order to improve the waterfastness of the inks for ink jet recording, it has been proposed to use ink comprising a pigment (see Japanese Patent Laid-Open Nos. 4-28776, 4-189876, 4-359071, and 4-359072), a non-aqueous medium (see Japanese Patent Laid-Open No. 4-261478), or a dye having excellent waterfastness (see U.S. Pat. No. 4,963,189).
However, use of a pigment in inks tends to incur a reduction in chroma of printed images and to cause clogging of the nozzles. Further, a pigment has insufficient fixation properties onto paper or an OHP (overhead projector) sheet, so that the printed image has insufficient record preservability. Neither has the other proposals succeeded in providing inks fully satisfying all the requirements, such as anti-blurring properties, waterfastness, and fixation.
Accordingly, an object of the present invention is to provide an aqueous ink which is prevented from blurring and provides printed images exhibiting improved waterfastness and improved fixation.
Another object of the present invention is to provide an aqueous ink which is particularly useful as an ink for ink jet recording.
DISCLOSURE OF THE INVENTION
In order to accomplish the above objects, the inventors of the present invention have extensively studied and found, as a result, that an aqueous ink containing a dye or a pigment is prevented from blurring and exhibits improved waterfastness and improved fixation without impairing the inherent color forming properties of the dye or pigment when the product (A) of a surface tension, a viscosity, and an average particle size of suspended particles (hereinafter sometimes simply referred to as "product (A)") is adjusted within a specific range.
For more preferably accomplishing the above objects, the inventors have found that the aqueous ink which is prevented from blurring and exhibits improved waterfastness and improved fixation without impairing the inherent color forming properties of the dye or pigment can be obtained by using a suspension in which a dye or a pigment is adsorbed onto micelles of a polyester or a polyester polyamide as a recording material and by adjusting the product (A) of a surface tension, a viscosity, and an average particle size of suspended particles within a specific range.
The present invention has been completed based on these findings. The present invention provides an aqueous ink comprising a suspension of a polymer, preferably a polyester or a polyester polyamide, having adsorbed a dye or a pigment as a recording material, wherein the surface tension (.gamma.) and the viscosity (.eta.) of the ink at 20.degree. C. and the average particle size (d) of the suspended particles satisfy the following inequality (1): and .mu.m, respectively.
The polymer in the aqueous ink provided by the present invention preferably has an acid value of 3 to 100 KOHmg/g as measured according to JIS K 0070 and a glass transition point of not lower than 20.degree. C. and contains, in its polymer chain, a unit derived from a diol component represented by formula (2) hereinafter shown (hereinafter described i
REFERENCES:
patent: 4692188 (1987-09-01), Ober et al.
patent: 4963189 (1990-10-01), Hindagolla
patent: 5242489 (1993-09-01), Schwarz et al.
patent: 5446082 (1995-08-01), Asai et al.
patent: 5679724 (1997-10-01), Sacripante et al.
Kawabe Kuniyasu
Sakuma Tadashi
Ueno Tetsuya
Kao Corporation
Merriam Andrew E. C.
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