JPH0742432B2 - Recording liquid - Google Patents

Description

TECHNICAL FIELD The present invention relates to a recording liquid for inkjet recording and writing instruments.

[Prior Art] In the inkjet recording method, when plain paper such as electrophotographic paper, bond paper, and stock form paper is used as the recording paper, image misalignment occurs even after the recording is rubbed with a finger or the like. There are problems such as shortening of the time until it does not occur (quick-drying property) and that the print has no bleeding and a clear contour (print quality).

Conventionally, a recording liquid containing a specific polymer is disclosed in Japanese Patent Laid-Open No. 50-
17,840, JP-A-50-102,407, JP-A-51-9,905,
JP-A-52-9,506, JP-A-54-62,005, JP-A-55-4
8,266, JP-A-55-80,477, JP-A-56-133,376,
JP-A-57-34,169, JP-A-59-53,563, JP-A-59-
53,565, JP-A-60-69,172, JP-A-60-76,574,
Although various publications such as JP-A-60-110,770 are known,
With respect to the above-mentioned problems, these recording liquids also have a large defect that a sufficient effect cannot be obtained, or even if the effect is obtained, the nozzle tip is likely to be clogged.

[Problems to be solved by the invention]

It is an object of the present invention to provide a recording liquid capable of obtaining printing that is quick-drying and has excellent printing quality even when recording is performed on plain paper.

[Means for solving problems]

The present invention includes a water-soluble dye, an aqueous medium, and the following general formula [I]. (In the formula, a represents a number of 15 to 10,000 and b represents a number of 0 to 7,500.) A recording liquid containing poly N-vinylformamide or a partial hydrolyzate thereof is summarized.

The poly N- represented by the above general formula [I] used in the present invention
Specific examples of vinyl formamide or a partial hydrolyzate thereof include: Etc., and its content is based on the total weight of the recording liquid.
A range of 0.5 to 5% by weight is included.

The poly-N-vinylformamide represented by the general formula [I] or a partial hydrolyzate thereof can be produced by various methods used for producing this seed polymer.

For example, as described in JP-A-61-97309, poly (N-vinylformamide) is prepared by synthesizing an N-vinylformamide monomer using acetaldehyde, formamide and methanol and then polymerizing in the presence of a radical polymerization initiator. Can be manufactured. At that time, various polymerization degrees can be produced by appropriately selecting the reaction conditions. However, when a low molecular weight polymer such as the specific example No. 1 of the general formula [I] is obtained, the following Examples As shown in 1, it can be polymerized in a solution in an organic solvent.

Further, high molecular weight polymers such as the compounds of the specific examples No. 2 to No. 4 are prepared by using a water-soluble polymerization initiator in the form of an aqueous solution as in the method described in Examples of JP-A-61-97309. It can be produced by polymerization.

Further, the partially modified product of poly-N-vinylformamide can be produced by the method described in JP-A-61-118406, JP-A-61-141712 and JP-A-61-190508, and a base Partially modified poly-N-vinylformamide such as the above specific examples No. 5 to No. 8 can be produced by modifying poly-N-vinylformamide under acidic or acidic conditions.

Examples of the water-soluble dye used in the present invention include azo-based, anthraquinone-based, quinophthalone-based, insidi-based and phthalocyanine-based direct dyes and acid dyes, such as C.
I.Direct Black-17, -19, -22, -32, -51, -80,
-91, -151 and -154, CIDirect Blue -86 and -19
9, CIDirect Red-80, CIDirect Yellow-86 and-
142, CIAcid Black-2, -24, -26, -48, -52,
-63, -172, -194 and -208, CIAcid Blue-9,-
185 and -254, CI Acid Red-8, -35, -37 and -25
7, CI Acid Yellow-23 and -49 and CI Food Black-
2 and the like.

The content of the above water-soluble dye is based on the total weight of the recording liquid.
The range is 0.2 to 12%, preferably 2 to 8%.

As the aqueous medium used in the present invention, in addition to water, for example, ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol (# 200), polyethylene glycol (# 400), glycerin, N-methyl- It preferably contains pyrrolidone, N-ethyl-pyrrolidone, N-vinyl-pyrrolidone, 1,3-dimethyl-imidazolidinone, ethylene glycol monoallyl ether, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether and the like.

The content of these aqueous media is in the range of 10 to 89.5% by weight based on the total weight of the recording liquid.

The pH of the recording liquid of the present invention is usually adjusted to 6-8.

Further, 0.1 to 10% by weight, preferably 0.5 to 5% by weight, of a compound selected from urea, thiourea, biuret and semicarbazide is added to the recording liquid of the present invention, or 0.001 to 0.5% by weight. By adding the above-mentioned surfactant, the quick-drying property after printing and the printed area can be further improved.

〔Example〕

 The invention is explained in more detail in the examples below.

The composition amount of Example 1 recording liquid (wt%) CIDirect Black-154 3 sufficiently Compound 3 Water balance Total 100 The above components ethylene glycol monoallyl ether 25 Ethylene glycol 22 the No.1 in a container After mixing and dissolving, and pressurizing with a Teflon filter having a pore diameter of 1 μm, deaeration was performed using a vacuum pump to prepare a recording liquid.

The No. 1 compound used in this example was produced by the following method.

[Polymerization example]

In a 300 ml reactor equipped with a cooling tube and a stirrer, 125 g of isopropyl alcohol, 25 g of N-vinylformamide and 0.1 g of azobisisobutyronitrile were placed, and the mixture was stirred under a nitrogen gas stream at 80 ° C. for 3 hours. The precipitate formed after cooling was filtered and then dried to obtain powdery poly N-vinylformamide in a yield of 99% based on the raw material monomer.

Using the obtained recording liquid, inkjet recording was performed with an inkjet printer (IP-130K, manufactured by Epson Corporation), and the quick-drying property and print quality were evaluated according to the following methods (a) and (b).

(A) Quick-drying: Printed on electrophotographic paper (manufactured by Fuji Xerox Co., Ltd.), bond paper and stock foam paper (manufactured by Lion Office Equipment Co., Ltd.), and after 30 seconds, rub the printed part with a finger to check for misalignment of the image. It was judged.

All of them showed no deviation and showed excellent fixability.

(B) Print quality: Each dot printed on the above recording paper was observed with a microscope, and the presence or absence of feathering (whisker-like bleeding) around the dot and the sharpness of the contour were visually evaluated.

All had no feathering and the contours were sharp.

Further, the inkjet recording was evaluated according to the following methods (c) to (f).

(C) Long-term storability of the recording liquid: After the recording liquid was sealed in a glass container and stored at 0 ° C and 60 ° C for 6 months, no insoluble matter was deposited, and the physical properties and color tone of the liquid did not change. There wasn't.

(D) Discharge stability: Continuous discharge was performed for 24 hours in each of the atmospheres of room temperature, 5 ° C., and 40 ° C., and stable high-quality recording could be performed from beginning to end under any conditions.

(E) Discharge responsiveness: Intermittent discharge every 2 seconds and discharge after being left for 2 months were examined. In both cases, stable and uniform recording was performed without clogging at the tip of the orifice.

(F) Quality of recorded image: The recorded image was high in density and clear. The rate of decrease in density after exposure to room light for 3 months was 1% or less, and when the film was immersed in water for 1 minute, image bleeding was extremely slight.

Preparing a recording liquid of the above composition in the same manner as compound 1.5 Water balance Total 100 Example 1 Example 2 Composition amount of recording liquid (wt%) CIDirect Black-19 3 Glycerin 10 ethylene glycol 10 the No.2 Then
As a result of examining (a) to (f), good results were obtained in all cases.

Examples 3 to 9 A recording liquid having the composition shown in Table 1 below was prepared according to the method of Example 1, and according to the methods of (a) to (f).
As a result of evaluation, all were favorable.

Example 10 As a water-soluble dye, CIDirect Black −51 or −9
1, CIDirect Blue-86, CIDirect Yellow-86, -1
42, CIAcid Black −26 or −63, CIAcid Blue
-9, or CIAcid-8 or -37, CIFood Bla
A recording liquid was prepared according to the method described in Example 1 except that each of ck-2 was used alone.
The examination of (f) was conducted. All obtained good results.

Example 11 As a water-soluble dye, CIDirect Black-80 or -15
1, CIDirect Red-80, CIAcid Black-48, -52,
-172, -194 or -208, CIAcid Blue-254, C.
I.Acid-35, 257 or CIAcid Yellow-23, -49 were used alone to prepare a recording liquid according to the method described in Example 3, and the recording liquid was prepared in the same manner as in Example 1 (a) to (f). Study was carried out. All obtained good results.

〔The invention's effect〕

The recording liquid of the present invention is used for ink jet recording, for writing instruments, etc., and has excellent quick-drying property after printing and excellent printing quality. It is possible to obtain an image in which there is no deviation and which has no blur and a sharp contour.

When the recording liquid of the present invention is used for inkjet recording, in addition to the above effects, recording characteristics (signal responsiveness, droplet formation stability, ejection stability, long-term continuous recording property), storage stability The light resistance, weather resistance and water resistance of the recorded image are all good.

Claims (5)

[Claims] 1. A recording liquid containing a water-soluble dye, an aqueous medium, and poly-N-vinylformamide represented by the following general formula [I] or a partial hydrolyzate thereof. (In the formula, a represents a number of 15 to 10,000 and b represents a number of 0 to 7,500.) 2. The content of the poly-N-vinylformamide represented by the general formula [I] or a partial hydrolyzate thereof is
The recording liquid according to claim 1, which is in a range of 0.5 to 5% by weight based on the total weight of the recording liquid. 3. The recording liquid according to claim 1, wherein the recording liquid further contains a surfactant. 4. The recording liquid according to claim 1, wherein the recording liquid has a pH of 6-8. 5. The recording liquid according to claim 1, wherein the recording liquid further contains a compound selected from urea, thiourea, biuret and semicarbazide.