JPS58136660A - Composition for masking paint - Google Patents

Abstract

PURPOSE:To provide the titled compsn. which can be applied by bursh coating or spray coating and can be easily removed after use, by adding a specified cellulose derivative to an aq. soln. of a water-soluble high-molecular material. CONSTITUTION:10-40wt.% at least one cellulose derivative selected from microcrystalline cellulose, CMC (acid) and Ca salt of CMC and, if necessary, a solvent, a plasticizer, a softener, etc. are added to an aq.soln. of a water-soluble high- molecular material such as Na salt of CMC.

Description

DETAILED DESCRIPTION OF THE INVENTION Conventionally, when painting articles in different colors, masking tape is used to cover the parts of the other colors before painting.

However, while masking tape is sufficient for flat parts, it is very inconvenient for masking curved or curved parts.

The present inventor conducted various studies and arrived at the present invention with the aim of creating a masking paint that can be applied by brushing or spraying and can be easily peeled off after use.

That is, the present invention is based on a water-soluble polymer aqueous solution, in which microcrystalline cellulose or carboxymethyl cellulose (acid) is added.
The main ingredient is fine powder of calcium salt of carboxymethylcellulose, or a combination of two or three, and if necessary, solvent, plasticizer, softener, water-insoluble. It is made up of inorganic or organic compound powder, etc. Examples of water-soluble polymers include sodium salt of carboxymethyl cellulose, hydroxyethyl cellulose, sodium polyacrylate, guar gum, arabic gum, starch, and the like.

The a degree of the water-soluble polymer water bath liquid depends on the viscosity of the water-soluble polymer used, so it cannot be determined unconditionally, but it may be determined as appropriate in consideration of workability. The viscosity of the water-soluble polymer used
]% The viscosity +i) of the water bath liquid at 25°C is 300 centipoise (when measured with a B-type viscometer at 6ORPM over one cycle)
A relatively low viscosity material such as the one below will give a thicker coating film and have a better masking effect.

Microcrystalline cellulose is a cellulose powder having a substantially constant degree of polymerization obtained by acid hydrolysis or alkaline oxidative decomposition of linters, pulp, and recycled fibers. Calcium salts of carboxymethylcellulose include those that are partially carboxymethylcellulose (acid) or mixed salts of sodium and calcium that are water-insoluble.

It is better to add as much microcrystalline cellulose and/or carboxymethyl cellulose (acid) and v/or carboxymethyl cellulose calcium salt as long as it does not harm the film formation of the water bath liquid polymer and the painting process. It is preferably about 10 to 40% by weight in the composition. If it is too small, it will take more time to peel it off after use.

The present invention is extremely convenient because it can be easily peeled off by washing with water after use. Also, depending on the type of water-soluble polymer used, the dried coating film may be crisp and brittle, and may
Since it does not adhere well to glass etc., it may be better to add a flexibility agent such as glycerin or ethylene glycol to increase the adhesion resistance to the painted surface.

In addition, if the drying time is longer than desired with a water-only solution (in such a case, it is also possible to shorten the printing time by adding a relatively low boiling point solvent such as methanol or ethanol).

The present invention will be described below with reference to examples, but is not limited thereto.

Example-1゜ An aqueous solution having the following composition (wt%) was prepared.

Sodium salt of carboxin methylcellulose 05%
water
Although it took 845% and took a long time to dry, it adhered well to the iron plate surface and was able to achieve a masking effect against spray painting of lacquer.

In addition, the viscosity of the sodium salt of carboxymethylcellulose used in this example (viscosity at 25°C of i aqueous solution)
was 100 centipoise (B-type viscometer, 60 RPM).

Example-2 An aqueous solution having the following composition was prepared.

Sodium salt of carboxymethylcellulose 4%1
'Avisel' PHIOI 1
5% glycerin 1% methanol 20% water
6
The viscosity of the aqueous solution obtained at 0% is 2 s o cps (B
(type viscometer 6ORPM, 25° C.), and had better adhesion resistance to iron plate surfaces and glass surfaces than that of Example-1, and there was no minute peeling at the peripheral portion.

The viscosity of the sodium salt of carboxymethylcellulose used in this example (the viscosity at 25°C of aqueous solution) was 9 centiboise (B-type viscometer, r, o RPM).
)Met.

Example-3゜ A water bath solution having the following composition was prepared.

Gum Arabic 10%
Calcium salt of carboquine methylcellulose 20% Edible Red No. 2 Trace amount of water
70%
The resulting aqueous slurry had very good fractional stability and was suitable for masking application to white backgrounds.

The viscosity of gum arabic used in this example (15
% aqueous solution at 25° C.) was 15 centipoise.

patent applicant Daicel Chemical Industries, Ltd.

Claims (1)

[Claims] A masking paint composition containing microcrystalline cellulose and/or carboxymethylcellulose (acid) and/or a calcium salt of carboxymethylcellulose, a water-soluble polymer, and water