JPS5821465A - White ink - Google Patents

Abstract

PURPOSE:White ink useful for marking, modification, etc., having improved redispersibility with time, consisting of titanium oxide, an electrolyte of an inorganic salt, a surface active agent, and water. CONSTITUTION:(A) Preferably 20-63wt% titanium oxide (preferably subjected to organic treatment) is blended with (B) preferably 0.3-0.7wt% electrolyte of an inorganic salt (preferably borax), (C) preferably 0.01-1wt% surface active agent, and (D) preferably 25-50wt% water, to give the desired white ink. EFFECT:Even if titanium oxide may precipitate, a hard cake is slightly formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a white ink with excellent redispersibility over time.

Conventionally, titanium oxide has been used as a pigment in white ink, and its dispersion method involves dispersing titanium oxide into fine particles using a ball mill, three-roll mill, etc., but although the initial dispersibility is good, it deteriorates over time. There was a problem that a hard cake was formed and redispersibility was poor.

There have also been attempts to improve the dispersibility by using a dispersant, but these have not yet been satisfactory.

The present inventors aimed to solve the above-mentioned problems.

As a result of studying various substances, we have finally completed the present invention, namely, 2. The gist of the present invention is a white ink consisting of at least titanium oxide, an electrolyte of an inorganic salt, a surfactant, and water. It is something.

It is not clear why the white ink of the present invention has excellent redispersibility over time. However, the surface of titanium oxide is moderately wetted by the action of a surfactant to disperse titanium oxide, and the titanium oxide and inorganic It is thought that it forms a light inorganic polymer with the salt electrolyte and exhibits a kind of cushioning effect, making it difficult to form a hard cake even if titanium oxide precipitates, resulting in excellent redispersibility over time. be done.

Hereinafter, nine aspects of the present invention will be described in detail.

Titanium oxide is used as a coloring material, and various types of titanium oxide such as rutile type and anatase type can be used, but among them, organically treated titanium oxide is used.

Preferred is titanium oxide, for example.

Bayert 1tan R-F D-1, same R-K
B-5゜R-OK-20 (manufactured by Bayer).

TIPAQUE R-650, TIPAQUE R-615. Same R-8
30, (manufactured by Ishihara Sangyo ■) tUnltaneO
R-542 (manufactured by A, O, O, Inc.), Ti-pure R
-900, R-901 (E, 1. Manufactured by Dupont)
There are many different types, depending on the purpose of use.

The amount used is 20 to 63% by weight based on the total amount of white ink.
is preferred.

Inorganic salt electrolytes are used to improve redispersibility over time, for example.

Examples include borax, borates, water glass, sodium carbonate, and potassium carbonate, with borax being particularly preferred.

If the amount used is less than 0.1% by weight based on the total amount of the white ink, the effect of improving redispersibility over time will be small.

If it is more than 1% by weight, the viscosity may become high and the ink dischargeability may deteriorate; therefore, it is 0.1 to 1% by weight.

More preferably α3 to 0.7% by weight.

The surfactant improves the wettability and dispersibility of titanium oxide, and various surfactants can be used. Examples of anionic surfactants include Demol P,
Polycarboxylic acid type activators such as Demol EP, Homogenol L-18, Poise 520, Poise 530 (manufactured by Kao Atlas ■), Discoat N-14, Discsol D-1 (manufactured by Daiichi Kogyo Seiyaku ■), etc. There is,
As the nonionic surfactant, Surfynol TG,
Surfynol 104B (or above + AirProdu
Acetylene glycol type activators such as ctsand Chemicals) and pegnol (Toho Chemical Co., Ltd.)
Polyoxyethylene alkyl ether type activator + such as AirProductsandC!he
micals) l nonal (manufactured by Toho Chemical Co., Ltd.),
Polyoxyethylene alkyl phenyl ether type activators such as Neugen EA (manufactured by Daiichi Kogyo Seiyaku) are available.
, can be used alone or in combination, and the amount used is preferably 0.01 to 1% by weight based on the total amount of the water-based ink.

Water is used as a solvent, and the amount used is preferably 25 to 50% by weight based on the total amount of white ink.

In addition, water-soluble resins and water-dispersible resins can be used as appropriate to improve adhesion to non-absorbing surfaces such as films, plastics, and glass, and the type and amount of resin used can be adjusted as appropriate depending on the purpose of the ink. decided on.

Furthermore, in order to improve the concealability of handwriting, silica powder such as alguna silicate or silica may be added, or the surface of titanium oxide may be treated with silica powder, which further improves wettability and freeze stability. First, polyhydric alcohol, urea, etc. are added, and next, leveling agents are added to improve leveling properties, and various other antifoaming agents are added.

Preservatives and antifungal agents can be added as appropriate.

Zero-shot white ink can be easily obtained by dispersing the above-mentioned components using various types of dispersers.

Crabs will be described in more detail below according to Examples.

In the examples, "parts" indicate "parts by weight."

Example 1 Bayer tLtan R-KB-5<titanium oxide y
) 317. O part 硼 sand
50 parts Demol EP (anionic surfactant) 1.5 parts DISCO)
N-14 (Anionic surfactant) a5 part Susu Finol TG (Nonionic surfactant)'
o, ss water
381.7 parts Primal AC-54446
3.0 parts (acrylic acid ester emul 9171 Japan Acry 4 water-dispersible resin) silica powder 76
．． 0 parts ethylene glycol 760 parts urea
7 parts 0 parts Shin-Etsu Silicone KM-73 (Shin-Etsu Chemical Co., Ltd.)
@Made by Kiki, antifoaming agent) 2.5 parts Broxel DRL (1
The desired white ink was obtained by pulverizing and dispersing the above-mentioned components using a ball mill.

Example 2 5.0 parts of borax in Example 1 was replaced with 2.0 parts of borax and 3.0 parts of water.
A white ink was obtained in the same manner as in Example 1 except that 0 part was added.

Example 5 5.0 parts of borax in Example 1 was used as borax aO part.

A white ink was obtained in the same manner as in Example 1, except that 3.0 parts of water was removed.

Comparative Example 1 A white ink was obtained in the same manner as in Example 1, except that 5.0 parts of borax and 5.0 parts of water were added.

Examples 1-3. Table 1 shows the test results of the redispersibility over time of the white ink obtained in Comparative Example 1.

Table □1 Test method 1.5 cIn diameter 3 parts m! 2 QmJ of the white ink obtained in Examples 1 to 3 and Comparative Example 1 was placed in a test tube.

After leaving it for an arbitrary period of time, gently stir the sedimented surface on which titanium oxide has settled using a microsphere.
Those that did not redisperse even after applying Iq were marked as ×.

As described above, the white ink of the present invention has good redispersibility and -
), it can be used for various purposes such as marking, correction, etc.

Patent applicant: Bentel Co., Ltd.

Claims (1)

[Claims] A white ink consisting of at least titanium oxide, an inorganic salt electrolyte, a surfactant, and water.