JPS5962680A - Foamable ink composition - Google Patents

Abstract

PURPOSE:To provide the titled composition giving uniform and rigid foamed coating film, by kneading a foaming agent, a pigment, etc. with an aqueous solution of a foam regulator, mixing the kneaded mixture with a solution of a water-based thermoplastic synthetic resin and a synthetic rubber latex, applying the obtained mixture by printing, and foaming the mixture with heat. CONSTITUTION:Preferably a water-based thermoplastic synthetic resin (preferably an aqueous solution of a thermoplastic synthetic resin such as 5-40wt% aqueous solution of polyvinyl alcohol, or a 20-50% emulsion of polyvinyl chloride, etc.) is mixed with a synthetic rubber latex (preferably acrylic rubber latex obtained by the emulsion polymerization) at a ratio of 95:5-50:50, and the obtained mixed solution is added with a dispersion obtained by kneading and dispersing a foaming agent such as an inorganic agent e.g. sodium bicarbonate, or an organic compound such as azobisisobutyronitrile, a foam assistant, an age resistor, a pigment, etc. in an aqueous solution of foam regulator (preferably a nonionic surface active agent). The obtained mixture is applied by printing, and foamed with heat to obtain the objective composition.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a foamable ink composition that forms a homogeneous foamed film by heating and foaming after printing.

Conventionally, foamable ink compositions include printing ink compositions made by adding heavy carbon soda, zinc oxide, and anti-aging agents to synthetic rubber latex, such as styrene-butadiene rubber latex (Japanese Patent Publication No. 49-14892), and polyvinyl chloride emulsions. Or a pasty mixture of paste with plasticizers, blowing agents, stabilizers, etc. (Japanese Patent Publication No. 33-9783), foaming agents in aqueous compositions of thermoplastic synthetic resins (condensation type, addition polymerized vinyl type, synthetic rubber type). , a foaming film-forming ink composition containing a foaming aid, a reinforcing agent, a plasticizer, etc.
-18152) are known.

However, all of these foamable ink compositions have the following drawbacks and are difficult to use in practice. In other words, foamable ink compositions made of synthetic rubber latex mixed with inorganic foaming agents, fillers, etc. dry quickly after printing, and the foamed film is hard and glossy, but the ink composition has a high viscosity and It is difficult to handle, and the foamed film is non-uniform and has a low expansion rate. On the other hand, the thermoplastic synthetic resin water-soluble composition contains a blowing agent, a blowing aid, a reinforcing agent,
Foaming ink compositions containing plasticizers, pigments, etc. dry well after printing and provide a good foamed film even if the printed film is thin, but the hardness of the foamed film is low and non-uniform. . Moreover, such aqueous compositions tend to cause precipitation of reinforcing agents, blowing agents, pigments, etc., and have the disadvantage of requiring thorough stirring during use.

The present invention solves the above-mentioned drawbacks and provides a homogeneous and hard foamed film by heating a thin printed film, and at the same time, it is a practical foaming ink that has an appropriate viscosity and does not produce deposits when used. A composition is provided. That is, (1) a mixed solution of an aqueous thermoplastic synthetic resin and a synthetic rubber latex is mixed with a foaming agent, a filler, a foaming aid, an anti-aging agent, a pigment, etc., which have been kneaded and dispersed in an aqueous solution of a cell regulator; A foamable ink composition characterized in that it is heated and expanded after being printed and applied, (2) the aqueous thermoplastic synthetic resin is composed of an aqueous thermoplastic synthetic resin solution and a thermoplastic synthetic resin emulsion composition; (3) the aqueous thermoplastic synthetic resin A mixed solution consisting of a thermoplastic synthetic resin and a synthetic rubber latex in a mixing ratio of 95:5 to 50:50. The present invention relates to a foamable ink composition characterized by mixing a foaming agent, a foaming aid, a filler, an anti-aging agent, a pigment, etc., which have been kneaded and dispersed in advance.

The present invention will be explained in more detail as follows.

The aqueous thermoplastic synthetic resin used in the present invention includes an aqueous thermoplastic synthetic resin solution and a thermoplastic synthetic resin emulsion. The thermoplastic synthetic resin aqueous solution contains polyvinyl alcohol, water-soluble acrylic resin, water-soluble polyamide resin (for example, one having a sulfonate group in the side chain), etc.
It is used as a 40% by weight (hereinafter abbreviated as %) aqueous solution.

Thermoplastic synthetic resin emulsions are produced by polymerizing vinyl chloride, vinyl acetate, styrene, methyl methacrylate, ethyl acrylate, etc.
Use as a 50% emulsion.

As the synthetic rubber latex, acrylic rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, and chloroprene rubber latex produced by emulsion polymerization reaction are preferably used.

Among water-based thermoplastic synthetic resins, foamed membranes made of water-soluble resins have the drawback of low hardness, low friction resistance, and poor water resistance. Since synthetic resin emulsions alone result in rough, inhomogeneous, hard and brittle foam coatings, plasticizers are generally added. As a result, a foamed film with low hardness and bleed properties is formed, which has the drawback of sticking to substrates such as paper and wood that come into contact with it and not being able to withstand long-term storage. Therefore, in order to improve these drawbacks, synthetic rubber latex was
~50 parts by weight (hereinafter abbreviated as parts), preferably 10~
By adding 40 parts, a good foamed film can be formed.

The blowing agent may be an inorganic compound or an organic compound. As the inorganic system, sodium heavy carbon, potassium heavy carbon, acidic sodium sulfite, ammonium carbonate, etc. are used. As an organic system, azobisisobutylonitrile (A
ZDN), para-toluenesulfonyl hydrazide (TS
H), 4,4'oxybisbenzenesulfonyl hydrazide (OBSH), azodicarboxylic acid amide (ADCA
), dinitrosopentamethylenetetramine (DPT), etc. are used alone or together with a foaming aid. The amount of blowing agent used is 1 to 10 parts, preferably 3 to 5 parts, per 100 parts of solid resin.

A foaming aid is used in combination with a foaming agent, and in particular, when used with a foaming agent that decomposes at a high temperature of 150° C. or higher, it has the effect of lowering the decomposition temperature of the foaming agent. As an acid, phthalic acid (
(phthalic anhydride), salicylic acid, stearic acid, etc., and the salts used include zinc stearate, lead, barium, adomium, complex salts thereof, and lead phthalate. Generally, the foaming aid is used in about the same amount as the foaming agent.

Fillers are used to increase the hardness and strength of the foam film, improve its abrasion resistance and slipperiness, and at the same time eliminate the stickiness of the film. and so on. Fine particles of 0.1 to several microns are used so that the filler is well dispersed when added to the foamable ink.

The anti-aging agent is phenyl α-naphthylamine (PA) to prevent deterioration of the synthetic rubber in the foamable ink composition.
), phenyl β-naphthylamine (D), aldol α
-Naphthylamine (C), styrenated phenol (SS
P), 2-mercapto benzo imidazole (MB)
etc.

The colorant is used in the ink, which is heated and foamed after printing, so dyes and pigments with good heat resistance are used.

Directly mixing foaming agents, foaming aids, fillers, anti-aging agents, coloring pigments, etc. into a mixed solution of water-based thermoplastic synthetic resin and synthetic rubber latex may cause thickening, precipitation, or uneven printing. This causes problems such as a non-uniform foamed film. Therefore, O/W
type (oil-in-water type) nonionic surfactants, such as polyoxyethylene sorbitan nolaurate (Tween 20 manufactured by Kao Atlas Co., Ltd.), polyoxyethylene monopalmitate (Tween 40 manufactured by Kao Atlas Co., Ltd.), polyoxyethylene nonylphenol ether (manufactured by Toho Chemical Co., Ltd.) A mixed solution of aqueous thermoplastic synthetic resin and synthetic rubber latex is prepared by kneading and dispersing powdered blowing agents, blowing aids, fillers, etc. in an aqueous solution such as Solphon F80) and pre-wetting the surface of the powder. can be mixed and dispersed very easily,
It does not cause thickening or precipitation. During heating and foaming, this nonionic surfactant plays a role in regulating bubbles and forms a homogeneous and fine foamed film.

The foamable ink composition according to the present invention described above is extremely stable and can withstand long-term storage, and its viscosity can be easily adjusted, so it can be used on various substrates such as paper, wood, fiber, metal, etc. be able to.

As for how to use it on a substrate, it can be used for printing such as gravure printing, screen printing, letterpress printing, etc., as a paint for brush painting, spray painting, etc., and further as a printing plate.

The foaming ink composition printed and applied onto the substrate is partially absorbed by the substrate, and at the same time, the foaming ink is adhered and solidified on the substrate by evaporation of water. Next, a temperature higher than the decomposition temperature of the blowing agent adjusted by the added blowing aid (
When heat treated at 90 to 120°C), the thermoplastic synthetic resin and synthetic rubber mixture dries and softens, and at the same time forms a homogeneous and fine foamed film due to the action of the decomposed gas of the blowing agent and the cell regulator. be able to. in this case,
The thickness of the foamed film can be adjusted as appropriate by changing the amount of the ink composition applied, the amount of the foaming agent added, the heating temperature and time.

The foamable ink composition according to the present invention can form a foamed film that is hard, glossy, homogeneous, and has good abrasion resistance, and the viscosity can be easily adjusted and precipitation does not easily occur. It can be suitably used for Braille printing, block printing, art, printing, decoration, and similar graphic arts.

The present invention will be explained below with reference to Examples.

Example 1 Preparation of Solution A Ethyl acrylate/methyl acrylate 70 parts Copolymerization emulsion (manufactured by Kansai Paint, resin content 50%) Acrylonitrile/butadiene rubber 30 parts Tex (manufactured by Nippon Zeon, rubber content 50%) Mix the emulsion and latex using a stirrer for about 10 minutes to obtain liquid A.

Preparation of Part B Foaming agent: dinitrosopentamethylenethe 5 parts Thoramine Foaming aid: Zinc stearate 5 parts Filler: Zinc oxide 20 parts Anti-aging agent: Phenyl α-naphthyla 1 part Mine Carbon black for printing (Columbia 10 parts) Raben 30 (manufactured by Carbon Co., Ltd.) Foaming regulator aqueous solution (10 30% aqueous solution of Tween 20) The above was stirred in a homomixer for about 30 minutes to obtain liquid B.

The B liquid was added to the A liquid and mixed for about 10 minutes using a mixing machine to obtain a foamable ink composition (viscosity 300C, P, S, etc.).

Braille and screen printing with this ink, 120° after air drying.
When heated for about 30 minutes in heating chamber C, Braille was expanded to a height of 0.3 mm and had a foamed coating that was hard and gave a pleasant feel to the fingertips and had good abrasion resistance.

Comparative Example 1 Both ethyl acrylate and methyl acrylate 100 parts Polymer resin emulsion (resin content 50% manufactured by Kansai Paint) Blowing agent: dinitrosopentamethylenetet 5 parts
Lamin foaming aid: Zinc stearate 5 parts Filler: Zinc oxide 20 parts Printing carbon black (Raven) 10 parts Water
30 parts of the above were stirred and mixed in a homomixer for about 30 minutes to obtain a foamable ink composition (viscosity: 500C, P, S). This ink composition was treated in the same manner as in Example 1 to obtain Braille characters. Although this ink had good foaming aid, Braille characters were obtained that had a soft and homogeneous foamed film with low abrasion resistance. This composition has a poor shelf life and forms a precipitate when left standing.

Comparative Example 2 Acrylonitrile-butadiene rubber latte 100 parts x (manufactured by Nippon Zeon, rubber content 50%) Foaming agent: dinitrosopentamethylenetet 5 parts Lamin foaming aid: zinc stearate 5 parts Filler: zinc oxide 20 parts Anti-aging Agent: Phenyl α-naphthylamine 1 part Printing Bomb Black (Raven 30) 10 parts Water
30 parts of the above were mixed in a homomixer for about 30 minutes to obtain a foamable ink composition (viscosity 700C, P, S).

This ink composition was treated in the same manner as in Example 1 to obtain Braille, but the ink had a low foamability and expanded to a height of 0 to 15 mm, resulting in Braille with a hard, non-uniform foamed film. .

This ink composition has a high viscosity and has poor printability, and when diluted with water, the viscosity decreases, but precipitation occurs.

Example 2 Preparation of Solution A Ethyl acrylate/methyl acrylate 70 parts Copolymer resin emulsion (manufactured by Kansai Paint, resin content 50%) Styrene/butadiene rubber latex 30 parts (manufactured by Nippon Zeon, rubber content 50%) Example 1 Mix as well.

Preparation of liquid B Foaming agent: 3 parts paratoluenesulfonylhydride
Radid foaming aid: Zinc stearate 3 parts Filler: Talc 10
Anti-aging agent: 1 part of aldol α-naphthylamine
Amine pigment: Phthalocyanine blue 5 parts bubble regulator aqueous solution (10 to 20 parts% of Tween 20)
Aqueous Solution) Liquid B was prepared in the same manner as in Example 1, and Liquid A and Liquid B were mixed to obtain a foamable ink composition. When a figure was printed using this ink and treated in the same manner as in Example 1, a figure with a hard, beautiful, homogeneous blue foam film was obtained.

Comparative Example 3 100 parts of styrene-butadiene rubber latex (
Made by Nippon Zeon, rubber 50%) Foaming agent: 3 parts paratoluenesulfonylhydra
ZID foaming aid: 3 parts zinc stearate Filler: 10 parts talc Anti-aging agent: 1 part aldol α-naphthyl
Amine Pigment: Phtacyloanine blue 5 parts water
When 20 parts or more were stirred and mixed in the same manner as in Comparative Example 2 and treated in the same manner as in Example 2, a figure almost similar to that in Comparative Example 2 was obtained.

Claims (1)

[Scope of Claims] 1 A mixed solution of an aqueous thermoplastic synthetic resin and a synthetic rubber latex is prepared by kneading and dispersing a foaming agent, a filler, a foaming aid, an anti-aging agent, a pigment, etc. in an aqueous solution of a bubble regulator. A foamable ink composition characterized in that it is mixed, printed, applied, and then heated to foam. 2. The foamable ink composition according to claim 1, wherein the aqueous thermoplastic synthetic resin comprises an aqueous thermoplastic synthetic resin solution and a thermoplastic synthetic resin emulsion. 3. The foamable ink composition according to claims 1 and 2, wherein the mixing ratio of the aqueous thermoplastic synthetic resin and the synthetic rubber latex is 95:5 to 50:50. 4. The foamable ink composition according to claim 1, wherein the foaming agent is comprised of an inorganic compound and an organic compound. 5. The foamable ink composition according to claim 1, wherein the foam control agent is a nonionic surfactant.