JP4145266B2 - Aqueous paint composition - Google Patents

Description

  The present invention relates to an aqueous paint composition, particularly a paint composition suitable for prints.

  Conventionally, water-based paint compositions are provided with a multivalent amount of glycerin, ethylene glycol, propylene glycol, dipropylene glycol, sorbitol, etc. in order to impart moisture retention and delay the drying rate when the paint is placed on a palette or drawn. Wetting agents such as alcohol and glycols are included (Patent Document 1).

JP 2001-146574 A

  However, the conventional wetting agent does not have sufficient water retention, and when an aqueous paint containing this is used for prints, the drying speed is still high, so it may dry out while being stretched by a roller, causing unevenness. If the ink is not printed immediately after it is applied to the plate, it may not be able to be printed clearly.

  On the other hand, polyacrylic acid soda is composed of a polymer dispersant (Patent Document 2, page 1, lower left column, lines 11-14), a thickener (Patent Document 3, page 2, upper right column, lines 3-4), wetting agent ( It is only used as a thickening inhibitor (Patent Document 5, page 2, column 2, lines 37-44).

JP-A-63-150357

JP 52-52716 A

JP2002-60700

  An object of the present invention is to provide an aqueous paint composition capable of further slowing down the drying speed of the paint, having good elongation and printability, and suitable for printing.

As a result of studying the above problems, if it is an aqueous paint composition containing sodium acrylate or a derivative thereof having a weight average molecular weight of 2 million to 6 million, the drying speed of the paint can be further reduced, and the elongation and printability is good, was found to be able to provide a suitable print water resistance paint compositions.

The present invention is an aqueous paint composition containing sodium polyacrylate having a weight average molecular weight of 2 million to 6 million or a derivative thereof.
As the polyacrylic acid soda or a derivative thereof, a water-soluble sodium polyacrylate or a derivative thereof can be used, but a water-insoluble cross-linked sodium polyacrylate or a derivative thereof can also be used.
The sodium polyacrylate is preferably contained in an amount of 0.1 to 30% by weight based on the total amount of the aqueous paint composition.

This ensures water retention compared to conventional water-based paint compositions containing a humectant, can further slow the paint drying speed, has good elongation and printability, and is suitable for prints. the water soluble paint composition can be provided.

[Humectant]
The present invention contains polyacrylic acid soda or a derivative thereof having a weight average molecular weight of 2,000,000 to 6,000,000 as a humectant to impart moisture retention and delay drying speed when a paint is stretched with a roller or applied to a plate. It is important to.
Here, in the case of sodium polyacrylate having a weight average molecular weight of less than 2 million or a derivative thereof,
In the case of polyacrylic acid soda or a derivative thereof having an insufficient moisturizing effect and having a weight average molecular weight exceeding 6 million, it becomes a gel and is not suitable as a printing material.

  The sodium polyacrylate or derivative thereof used in the present invention is preferably water-soluble sodium polyacrylate or a derivative thereof, but a cross-linked water-soluble sodium polyacrylate or derivative thereof can also be used.

  The content of sodium polyacrylate or a derivative thereof used in the present invention is 0.1 to 30% by weight, preferably 0.5 to 20% by weight, based on the total amount of the paint composition. When the content of the sodium polyacrylate or the derivative thereof is less than 0.1% by weight, the moisture retention becomes worse, the drying speed increases, and the paint stretches when stretched with a roller or applied to a plate. Becomes worse. When the content of the sodium polyacrylate or the derivative thereof exceeds 30% by weight, the viscosity increases too much and the elongation of the paint deteriorates, resulting in uneven printing.

  In addition, although this invention can use the said polyacrylic acid soda or its derivative individually or in combination of 2 or more types, it is also possible to use together the well-known moisturizer normally used as a paint composition. . Examples include acrylic acid / maleic acid copolymer salts, urea or derivatives thereof, and polyhydric alcohols such as glycerin, propylene glycol, and ethylene glycol.

[Coloring pigments]
Examples of the pigment used in the present invention include carbon black, aniline black, iron black, titanium oxide, alumina silica, talc and other inorganic pigments, ultramarine and bitumen, azo pigments, naphthol pigments, and phthalocyanines. Pigments, selenium pigments, quinacridone pigments, anthraquinone pigments, dioxane pigments, dioxazine pigments, indigo pigments, thioindigo pigments, perinone pigments, perylene pigments, indolenone pigments, azomethine pigments, etc. Metal pigments such as organic pigments, lake pigments, aluminum powders, bronze powders, fluorescent pigments, pearl pigments, glitter pigments, and the like can be used.

  The content of the color pigment used in the present invention is 60% by weight or less, preferably 10 to 40% by weight, based on the total amount of the paint composition. When the content exceeds 50% by weight, the viscosity increases so much that the elongation of the paint deteriorates, so that it tends to be a coated surface with brush unevenness. When the content is less than 10% by weight, the coloring power is lacking and it is not suitable as a print paint.

[Water-soluble resin]
In the present invention, a water-soluble resin can be used to fix the pigment or disperse the pigment. For example, gum arabic, dextrin, carboxymethyl cellulose, hydroxyethyl cellulose, styrene acrylic copolymer, styrene malee copolymer, polyvinyl pyrrolidone (PVP), guar gum, xanthan gum, welan gum, leozan gum and the like can be mentioned. These can be used alone or in combination of two or more.

  The content of the water-soluble resin used in the present invention is 0.1 to 50% by weight or less, preferably 0.5 to 30% with respect to the total amount of the paint composition. When the content of the water-soluble resin is increased to 50%, the coloring power is lost and the coating film is easily glossy. In addition, the adhesive strength is increased, and the plate and paper are likely to stick together. When the content of the water-soluble resin is less than 0.1% by weight, the fixability on the printed surface is deteriorated.

[Surfactant]
In the present invention, a surfactant can be used to prevent the paint from repelling on the plate. As the surfactant, anionic surfactants such as β-naphthalenesulfonic acid soda formalin condensate and nonionic surfactants such as polyoxyethylene alkyl (allyl) ether phosphate can be used, and the above-mentioned surfactants alone or It can be used in combination. Surfactant can be used 1 type or in combination of 2 or more types.

  The content of the surfactant used in the present invention is 0.01 to 10% by weight, preferably 0.1 to 3% by weight, based on the total amount of the paint composition. When the content of the surfactant exceeds 10% by weight, it easily penetrates into the printed surface. When the content of the surfactant is less than 0.01% by weight, the paint is easy to repel on a rubber plate or the like and is not suitable as a print art.

  In addition, other additives such as water, preservatives, antifungal agents, thickeners and the like can be added and mixed. It is desirable to mix 10 to 50% by weight of water with respect to the total amount of the paint composition.

  In the composition shown in Table 1, first, a water-soluble resin is dissolved in water, and then an aqueous solution, a color pigment, a surfactant, a humectant, and water are weighed and stirred with a dissolver until uniform. Each of the paint compositions of Examples and Comparative Examples was obtained by passing and dispersing three times with this roll meal.

In the table,
Coloring pigments ・ Product name "Seika First Yellow 2070" (CI11680 manufactured by Daiichi Seika Co., Ltd.)
Colored pigments, trade name "N067 Carplex" (hydrous amorphous silicon dioxide, manufactured by Shionogi)
Surfactant ... Trade name "Labelin FC-P" (anionic surfactant, manufactured by Daiichi Kogyo Kagaku Co., Ltd.)
Moisturizer ・ Product name “AQUALIC FH-H” (sodium polyacrylate, molecular weight 5 million to 6 million, manufactured by Nippon Shokubai Co., Ltd.)
・ Product name “AQUALIC FH-K” (sodium polyacrylate, molecular weight 2 million to 3 million, manufactured by Nippon Shokubai Co., Ltd.)
・ Product name "Aquaric DL40" (sodium polyacrylate, molecular weight 3500, manufactured by Nippon Shokubai Co., Ltd.)
Antiseptic / Product name "Proxel XL-2" (Abyssia)

Next, the drying speed, elongation, and printability of the paint were evaluated.
[Drying speed]
After applying 2 g of the print paints of the examples and comparative examples shown in Table 1 uniformly on a wood block of 16 cm in length and 10 cm in width with a flat brush, measure the time until the finger touches the finger and does not stick to the finger, Evaluation was made according to the following criteria.
(Evaluation criteria)
○: 20 minutes or more Δ: 10 to 20 minutes ×: 10 minutes or less [elongation]
Next, on each metal tray, 10 g of the printing materials of Examples and Comparative Examples shown in Table 1 were put and stretched with a printing roller, and the degree of elongation was evaluated according to the following criteria.
(Evaluation criteria)
○: The paint is easy to get on the roller and stretches well ×: The paint is hard to get on the roller, and the stretch is poor [printability]
Next, 2 g of the printing materials of Examples and Comparative Examples shown in Table 1 above are uniformly applied with a flat brush on a wood block of 16 cm in length and 10 cm in width, and then printed on the Shima Bunko.
Evaluation ○: Can be printed cleanly without unevenness △: There is some unevenness, but it can be printed normally ×: The unevenness is severe, or the paper is stuck to the wood block at the part where the paint is dry

  From Table 1, the paint composition of each Example having a weight average molecular weight of 2,000,000 to 6,000,000 can further reduce the drying speed of the paint as compared with the paint of the comparative example, and the elongation and printability are good. It was found to be suitable for prints.

Since the aqueous paint composition of the present invention has a low drying rate and good elongation and printability, it can be suitably used as a print paint, in addition to a watercolor paint and a solid paint.

Claims (5)

Containing sodium polyacrylate or a derivative thereof having a weight average molecular weight of 2 million to 6 million ,
Wherein sodium polyacrylate is water soluble paint composition containing 0.1 to 30% by weight relative to the aqueous paint composition the total amount.     The aqueous paint composition according to claim 1, wherein the sodium polyacrylate or a derivative thereof is a water-soluble sodium polyacrylate or a derivative thereof.     The aqueous paint composition according to claim 1, wherein the sodium polyacrylate or a derivative thereof is a cross-linked sodium polyacrylate or a derivative thereof. An aqueous paint composition containing a color pigment, a paste, a surfactant, a wetting agent and water,
For the total amount of the composition,
60% or less of the color pigment,
0.1-50% by weight of the paste,
0.01 to 10% by weight of the surfactant,
0.1 to 30% by weight of polyacrylic acid soda or a derivative thereof having a weight average molecular weight of 2 to 6 million as the wetting agent,
The remaining water,
Aqueous paint composition included . An aqueous printing material comprising the composition according to any one of claims 1 to 4 .