JP2009227707A - Aqueous coating agent composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aqueous coating agent which imparts a soft, velvet- or suede-like texture to a substrate of printed matter such as a paper package for the purpose of increasing its premium look and appealing power. <P>SOLUTION: The aqueous coating agent composition contains a styrene-acrylic resin and a urethane resin, wherein (a) the styrene-acrylic resin has a glass transition point of from -10 to 150°C and (b) the urethane resin is a bead having an average particle size of 0.1-10 μm and accounts for 10-30 mass% of the coating agent in terms of volatile content. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an aqueous coating agent composition which is applied to the surface of a printed material such as paper and imparts a soft velvet or suede feel to the surface.

  Conventionally, in the commercial printing field (mainly in the packaging field), a coating varnishing process that applies a coating agent (also called varnish in the industry) to the printed material for the purpose of cosmetic decoration and surface protection of the printed material, varnished printed material Various surface treatments such as press working for applying a specular gloss to the printed matter by heating and pressurizing with a stainless steel plate and laminating for attaching a film such as OPP or PET to the printed matter are performed.

  In recent years, more and more attempts have been made to give cosmetics and functions unprecedented to printed matter to differentiate them from competing products. The reason for this is that the design, function, design, and cosmetics of printed paper containers have a great influence on product sales.

In terms of function, imparting friction resistance, blocking resistance, slipperiness, heat resistance, water repellency, oil resistance and other characteristics are performed.
In addition, surface processing is performed that is characterized by touch when touched with a hand.

Patent Document 1 describes a suede finish paint having no color fading and excellent stain resistance.
Patent Document 2 describes a urethane resin composition for coating excellent in surface properties such as waterproofness, soft touch feeling, and slipperiness.
Patent Document 3 describes a water-dispersible coating composition containing a water-based acrylic resin, which contains urethane beads as a matting agent and can obtain a suede-like finish.
Patent Document 4 describes an aqueous coating agent containing styrene / acrylic resin and polyethylene wax, which has an excellent matting effect and anti-slip effect.

Japanese Patent Laid-Open No. 06-073307 JP 09-118734 A JP 2002-212490 A JP 2005-298666 A

  An object of the present invention is to provide an aqueous coating agent that imparts a soft velvet or suede feel to a substrate such as printed matter.

As a result of intensive studies, the inventors have coated velvet with a water-based coating agent composition that satisfies all of the following conditions (a) to (e), whereby the coated surface has a superior velvet feeling: The present invention has been found by forming a tone film (i) containing a urethane resin and a styrene / acrylic resin.
(B) The urethane resin is a bead having an average particle diameter in the range of 0.1 to 10 μm.
(C) The content of the urethane resin in the aqueous coating agent composition is 10 to 30% by mass in terms of nonvolatile content. That is, the ratio in which the nonvolatile content in the urethane resin is contained in the aqueous coating agent composition is 10 to 30% by mass.
(D) The content of the styrene / acrylic resin in the aqueous coating agent composition is 3 to 30% by mass in terms of nonvolatile content, and the glass transition temperature is −10 to 150 ° C.
(E) The minimum film forming temperature of the aqueous coating agent composition is -5 ° C to 50 ° C.

  The aqueous coating agent composition of the present invention can form a velvet-like soft and high-quality film on the surface of printed matter, paper containers, and the like.

The aqueous coating agent composition of the present invention contains a styrene / acrylic resin as a main resin and a urethane resin. A urethane resin is used in the form of beads. The average particle diameter is preferably in the range of 0.1 to 10 μm, more preferably 1 to 6 μm.
The content of the styrene / acrylic resin in the aqueous coating agent composition is preferably 3 to 30% by mass in terms of nonvolatile content.
As the styrene / acrylic resin, an aqueous solution, an emulsion, or a mixture thereof can be used. In the case of an aqueous solution, the acid value is preferably 100 to 250, and the glass transition point is preferably -10 to 150 ° C. In the case of an emulsion, the acid value is preferably 40 to 200 and the glass transition point is preferably -10 to 150 ° C.
When a mixture of an aqueous solution and an emulsion is used, the glass transition point of the styrene / acrylic resin is preferably −10 to 120 ° C.

As the urethane resin, beads or those obtained by dispersing beads in an aqueous solvent (hereinafter also referred to as a dispersion) can be used.
When the urethane resin to be used is a dispersion and its non-volatile content is 50% or less, the viscosity of the aqueous coating agent composition as a whole may decrease due to an increase in the amount of addition.
In that case, the viscosity can be adjusted by adding a relatively high viscosity styrene / acrylic emulsion, water-soluble resin, alkali-thickened resin, or the like. Furthermore, it adjusts with a thickener as needed.

  The general use viscosity of the aqueous coating agent composition of the present invention is 9 to 20 seconds (when Zahn Cup # 4 is used), and more preferably 15 to 20 seconds. When the viscosity is low, a thickener can be added to increase the viscosity.

As an auxiliary means for obtaining a preferable velvet feeling, fine adjustment of the velvet feeling can be performed by adding an oxidized polyethylene wax, a silicone compound, or a phosphoric acid ester aqueous solution.
As an example of the phosphoric acid ester, an isodecyl phosphoric acid aqueous solution (active ingredient 37.8%, one neutralized with 48% KOH aqueous solution) is preferably used.

In order to produce the aqueous coating agent composition of the present invention, first, the styrene / acrylic resin solution (aqueous solution and / or emulsion) is dispersed and mixed with a stirrer, and urethane resin (beads or dispersion) is added while stirring is continued. To do.
Next, a surfactant, a high-boiling solvent and other auxiliaries are added, and dissolved and mixed by stirring.
Then, an aqueous phosphate ester solution prepared in advance is added with stirring, and mixed so that the whole becomes uniform.

The following examples illustrate the invention.
According to the formulation shown in Tables 1 and 2, the aqueous coating composition Nos. In Examples were used. 1-14 were produced. Numerical values are based on mass.
The prototype in Table 1 corresponds to a coating agent that forms a glossy and smooth film generally used conventionally. The prototype does not include the urethane resin, which is a main component that imparts a velvet-like feel in the present invention.

The ingredients in Tables 1 and 2 are as follows:
Raw material A: acrylic acid / α-methylstyrene / styrene / ethyl carbitol acrylate / 2-ethylhexyl acrylate (= 12.8 / 20.4 / 33.6 / 1.2 / 32) copolymer emulsion (non-volatile content 44%, acid value 100, glass transition point 16) ℃)
Raw material B: acrylic acid / styrene / α-methylstyrene / ethyl carbitol acrylate (= 27.1 / 11.8 / 54.3 / 6.8) copolymer water-soluble resin solution (non-volatile content 33%, acid value 195, glass transition point 113 ° C., weight average) Molecular weight 8000)
Raw material C: Urethane (particle diameter of about 1.9 μm)
Raw material D: Urethane (particle diameter of about 6 μm)
Raw material E: Urethane (particle diameter about 10 μm)
Raw material F: Isopropyl alcohol raw material G: Polyethylene wax dispersion (non-volatile content 40%, average particle size 4 μm, softening point 110 ° C.)
Raw material H: Wetting agent (dioctyl succinic acid sodium salt)
Raw material I: Water raw material J: Film forming aid: Diethylene glycol monobutyl ether acetate raw material K: Emulsion-type silicone antifoam raw material L: Oxidized polyethylene wax dispersion (nonvolatile content 20%, melting point 130 ° C., average particle size about 0) .1 μm)
Raw material M: Silicone compound raw material N: Isodecyl phosphate aqueous solution

(Preparation of coating products for evaluation)
The aqueous coating agent shown in Table 1 and Table 2 is applied to coated paper, on which a pattern has been printed in advance with an oxidation polymerization drying type offset ink, with a bar coater # 6, and then dried at a set temperature of 80 ° C. for 10 seconds. Then, it was left at room temperature for 1 day to obtain a coating processed product for evaluation.
Using the obtained workpiece, evaluation was performed according to the following evaluation test method.
(Evaluation methods)
Five members of the development department of this product touch with their hands and fingers to evaluate the degree of velvet touch. As the evaluation value, a value having a strong and excellent velvet feel was regarded as a high numerical value, and an arithmetic average of values given in the range of 0 to 100 was used. The results are shown in the bottom row of Tables 1 and 2.
If the evaluation value is 35 or more, it has a practically sufficient velvet feel.

  By processing the surface of a printed matter or paper container using the aqueous coating agent composition of the present invention, a velvet-like soft and high-quality film can be formed, and the appeal can be enhanced.

Claims (3)

An aqueous coating composition that satisfies all of the following conditions (a) to (e):
(A) Contains urethane resin and styrene / acrylic resin.
(B) The urethane resin is a bead having an average particle diameter in the range of 0.1 to 10 μm.
(C) The content of the urethane resin in the aqueous coating agent composition is 10 to 30% by mass in terms of nonvolatile content.
(D) The content of the styrene / acrylic resin in the aqueous coating agent composition is 3 to 30% by mass in terms of nonvolatile content, and its glass transition point is −10 to 150 ° C.
(E) The minimum film forming temperature of the aqueous coating agent composition is -5 ° C to 50 ° C. The styrene / acrylic resin comprises a (meth) acrylic acid ester, a carboxyl group-containing vinyl monomer, and a monomer copolymerizable therewith,
The aqueous coating agent composition according to claim 1, which is an aqueous acrylic resin obtained by copolymerizing a monomer component containing (meth) acrylic acid ester as a main component.   The styrene-acrylic resin is a core / shell aqueous acrylic resin emulsion having a core part having a weight average molecular weight of 100,000 to 500,000 and a shell part having a weight average molecular weight of 5,000 to 50,000. 2. The aqueous coating agent composition according to 1.