JPH01139660A - Oil pigment ink composition for writing utensil - Google Patents

Abstract

PURPOSE:To obtain the title ink composition having suitable low viscosity, high stability with time, low odor and excellent fixability of written mark, by compounding a pigment surface-treated with an aluminum-based coupling agent, a polyvinyl butyral resin, shellac, etc. CONSTITUTION:The objective ink composition having high compatibility between a polyvinyl butyral resin and a pigment treated with an aluminum-based coupling agent and giving a fluidity and dispersion stability suitable for writing utensil can be produced by compounding (A) 3-20wt.% (based on the whole ink) of a pigment surface-treated with 0.01-50wt.% of an aluminum-based coupling agent, (B) 0.1-2wt.% of a polyvinyl butyral resin, (C) 0.5-10wt.% of shellac and (D) an alcohol ether solvent and/or a glycol ether solvent.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a low-viscosity oil-based pigment ink suitable for writing instruments, particularly so-called cotton-filled writing instruments, and more particularly, it relates to a low-viscosity oil-based pigment ink that has good stability over time and low This invention relates to an oil-based pigment ink for writing instruments that is odorless and has excellent handwriting fixation properties.

(Prior art) Conventionally, oil-based inks have been widely used because they can be written on both absorbent surfaces such as paper and cloth, and non-absorbent surfaces such as plastic, glass, and metal, and they dry quickly. In particular, those using pigments as colorants are being put into practical use because they improve the fastness of handwriting.

However, conventional oil-based pigment inks use oil-soluble resins to disperse pigments and provide handwriting fixation, and have a relatively high viscosity, resulting in less ink being ejected from the pen tip and causing blurring of handwriting. Furthermore, pigment sedimentation occurs over time, causing clogging at the pen tip and a decrease in handwriting density.

As a writing instrument, a valve structure is placed between the pen tip and the ink reservoir to eliminate insufficient ink discharge, and a stirring member such as a metal ball is placed inside the ink reservoir to redisperse the settled pigment. The following configuration is used.

(Problems to be Solved by the Invention) However, the writing instrument having the above structure has the problem of increasing the number of parts and complicating the manufacturing work, resulting in an increase in cost. Oil-based pigment inks used aromatic hydrocarbon solvents such as toluene and xylene, and ester solvents such as ethyl acetate and butyl acetate to dissolve oil-soluble resins, resulting in a strong odor. was.

Therefore, one object of the present invention is to provide an ink that can be used in writing instruments without a valve structure or stirring member as described above, that is, has a low viscosity and good stability over time, has low odor, and has excellent handwriting fixation properties. The purpose is to obtain an excellent oil-based pigment ink for writing instruments.

(Means for Solving the Problems) The present invention was made to achieve the above object, and includes a pigment surface-treated with an aluminum coupling agent, a polyvinyl butyral resin, shellac, and an alcohol. The gist of the present invention is an oil-based pigment ink composition for writing instruments, which comprises at least a glycol ether-based solvent and/or a glycol ether-based solvent.

Each component of the oil-based pigment ink composition for writing instruments of the present invention will be explained below.

Aluminum-based coupling agents are used for surface modification of pigments, and specifically, Pre-Act A
There are ALCH, ALCH-TR, I2-M (manufactured by Ajinomoto), Aluminum Chelate M, D, and A (manufactured by Yoken Fine Chemicals), which can be used as a processing agent before pigment dispersion, or Alternatively, it can be used by adding it when dispersing the pigment. The amount used varies depending on the type of pigment, but it is based on the amount of pigment used.

0.01 to 50% by weight is preferred.

The pigment is used as a coloring agent and is not particularly limited, and may include azo pigments, phthalocyanine pigments,
Organic pigments such as nitroso pigments, nitro pigments, basic dye pigments, acid dye pigments, vat dye pigments, mordant dye pigments, and natural dye pigments, ocher, barium yellow, and navy blue.

Examples include inorganic pigments such as cadmium red, barium sulfate, titanium oxide, red iron black, iron black, aluminum hydroxide, calcium carbonate, and carbon black. It is preferably 3 to 2% by weight.

Polyvinyl butyral resin (hereinafter abbreviated as PVB).

) is used as a dispersant, anti-settling agent, and fixing agent for pigments, and for the fastness of handwriting and the dispersion stability of ink, it is preferable to add it in a large amount in the ink. As the agent and antisettling agent, it is preferable that the degree of polymerization is high. In particular, when used in a writing instrument having a discharge mechanism that utilizes capillary phenomenon, if there is insufficient dispersion stability, the problem arises that the pen tip becomes clogged, resulting in blurred writing.

However, if the amount added is large or the degree of polymerization is high, the viscosity of the ink will increase. On the other hand, writing instruments that have a discharge mechanism that utilizes capillary phenomenon, such as felt pen nibs,
The viscosity of the ink suitable for use in writing instruments with fiber or plastic nibs is 20 cps (
at 25°C) or less, more preferably 15 cps (at
25° C.) or less, therefore those with an average degree of polymerization of 1000 or less are preferably used, specifically Denka Butyral #2000-L, Denka Butyral #3000-1. Same 13000-2
．． #3000-4, #13000-2. Same #4000
-2 (hereinafter referred to as Electrochemical Industry Cleavage), S-LEC BL-
1° Same BL-2. Same BL-3. Same BL-8, Same BX-L
, same BM-1. Same BM-2, Same BM-5゜ Same BM-
8 (manufactured by Tanemizu Chemical Industry ■), and the amount used varies depending on the average degree of polymerization, etc., but the weight ratio (PvB/pigment) to the pigment is in the range of 0.1 to 2.0. desirable.

Shellac is used as a fixing agent, specifically,
Drying transparent rack, C8, NC3, SSI, GN (more than 1
Nippon Sheratsuk Kogyo■'M), transparent mortar rack GBN-D
, GBN, Milky White Lac 0B-D, GB (manufactured by Gifu Shellac Seisakusho ■), etc. can be used alone or in combination, and the amount used is 0°5 based on the total amount of ink.
~10ffi amount% is preferred.

Alcohol solvents and glycol ether solvents are solvents used to reduce the odor of ink, and
Specifically, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, 5eC
-butyl alcohol, tert-butyl alcohol, n
-Amyl alcohol, isoamyl alcohol.

Examples include 5ec-amyl alcohol, n-hexanol, methyl cellosolve, ethyl cellosolve, isopropyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether, and the like.

In addition, as components other than those mentioned above, resins, surfactants, rust preventives, dispersion aids, lubricants, etc. may be used as appropriate.

As a method for producing the oil-based pigment ink composition for writing instruments according to the present invention, a conventionally known method can be adopted, and the above-mentioned components are cross-dispersed using a dispersing machine such as a homomixer, a ball mill, a homogenizer, a sand mill, a roll mill, etc. It can be easily obtained by

(Function) Why is the oil-based pigment ink composition for writing instruments according to the present invention
It has a low viscosity and good stability over time, and although it is not clear whether it has excellent handwriting fixation, the pigment surface-treated with an aluminum coupling agent and PVB have a good affinity, so capillary action is possible. It provides fluidity and dispersion stability suitable for writing instruments with a discharge mechanism that utilizes aluminum, and at the same time provides strong fixing properties due to the interaction between the pigment surface-treated with an aluminum-based coupling agent, PVB, and shellac. It is assumed that it will appear.

(Example) Hereinafter, the present invention will be explained in more detail with reference to Examples, and the numerical values in Table 1 indicate parts by weight.

(Left below) 1. Ink composition table 1 *1: Carbon black, manufactured by Mitsubishi Chemical Industries *2: Permanent red, manufactured by Dainippon Ink & Chemicals *3: Copper phthalocyanine, manufactured by Toyo Ink & Chemicals *4: Insoluble azo pigment, manufactured by Dainichiseika Kogyo@*5: Rosin ester, manufactured by Harima Kasei Kogyo ■*6: Oil-soluble alkanolamide blend (dispersion aid), manufactured by Kadenka Kogyo ■ Comparative Example 5 MA-10010, 0 parts Nitrocellulose LL/8 20.0 parts Hari7terjL/193HV 20.0 parts (alkyd resin, manufactured by Harima Kasei Kogyo ■) Xylene
20.0 parts ethyl acetate
15.0 parts cellosolve acetate 15.
Part 0 2, Pigment surface treatment method Examples 1 to 4 and Comparative Examples 2 and 4 are as follows: Dissolve the coupling agent in twice the amount of normal hexane as the pigment, add the pigment to this, and stir in a closed homomixer. After mixing and treating the pigment surface, normal hexane was removed.

3. Method for producing ink The above ingredients were thoroughly mixed and subjected to a marking treatment in a ball mill for 30 hours to obtain an ink.

(Effect of the invention) Tests were conducted on the inks obtained in Examples 1 to 4 and Comparative Examples 1 to 5. The results are shown in Table 2.

Table 2 Viscosity Measured using a Type 2 B viscometer, BL adapter, and 25°C.

Dispersion stability test: Each ink was placed in a test tube with a lid and subjected to a cold/heat cycle (50'Ca-5°C, 1 o cycle at 24 hours per cycle), and the condition of the pigment settling at the bottom was observed for 11 days.

O: No sediment was observed at all.

Δ: There is sediment, but it is a small amount.

x: Pigment sediments and separates into two layers.

Pen nib clogging test: Each ink was filled into a sign pen with a fiber nib made of acrylic resin fiber hardened with thermosetting resin, left for 3 months, and then written on, and the handwriting was visually judged. .

O: Good handwriting without clogging.

×: Clogging occurs and the handwriting becomes blurred Fixation test: Each ink is filled into a felt-tip pen with a fiber nib made of acrylic resin fiber hardened with thermosetting resin, written on a well-washed glass surface, and left at room temperature. After drying for 1 hour, cellophane tape was pasted onto the handwriting, sufficiently pressed, the tape was peeled off, and the condition of the handwriting was visually determined.

○: No peeling of handwriting.

Δ: Partial peeling of handwriting.

×: The handwriting is completely peeled off.

Odor test: Sensory test using 20 monitors.

0: Low odor (no unpleasant odor) X: Strong odor (with unpleasant odor) As explained above in detail, the oil-based pigment ink for writing instruments according to the present invention has a low viscosity, so It can be suitably used in writing instruments that do not have a stirring member in the ink storage chamber, and has excellent dispersion stability, so it does not clog the pen tip and has excellent handwriting fixation. Pentel Co., Ltd. Procedural Amendment August 3, 1988 Patent Application No. 298674 of 1988 2, Name of the invention 'j, Person who makes Pilf +E/IC matter Relationship Patent amount Lm people・1. Rejected talent 2 colors 1! 1! Mountain notification date (]) Akira, Yffl'+! Replace page F with the attached sheet.

(Attachment) 1. Ink composition Table 1

Claims (1)

[Claims] An oil-based pigment ink composition for writing instruments comprising at least a pigment surface-treated with an aluminum-based coupling agent, a polyvinyl butyral resin, shellac, and an alcohol-based solvent and/or a glycol ether-based solvent.