JP2003313509A - Binder for coating for vacuum coater and coating for vacuum coater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating for a vacuum coater having good drying and film-forming properties and suitable for use in the vacuum coater for passing a material to be coated through a coating mist and coating the material. <P>SOLUTION: A binder for the coating comprises a polymer emulsion obtained by carrying out emulsion polymerization of 1-10 wt.% of a hydrophilic group- containing monomer and 90-99 wt.% of other monomers in an aqueous medium and having 10-80°C glass transition temperature. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a binder for a coating material for a vacuum coating machine and a coating material for a vacuum coating machine using the binder.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
Board sealing materials used for boards such as siding boards used as interior / exterior wall materials have been applied by rolls or sprays. Toroko recently
A vacuum coating machine has been developed, which coats a coating material through a coating mist. With this, it became possible to broaden the range of choice of paints.

However, in the case of coating with this vacuum coating machine, the coating material dries quickly. Therefore, if the board sealing material that has been used so far is used, a film made of the board sealing material will stick to the periphery of the vacuum coating machine, There has been a case where a board as a base material is contaminated. Further, there has been a problem that bubbles are generated in a film made of a board sealing material.

Therefore, the present invention provides a paint for a vacuum coating machine which has good drying properties and film-forming properties and is suitable for use in a vacuum coating machine in which a material to be coated is passed through a coating mist for coating. The purpose is to do.

[0005]

The present invention is directed to a hydrophilic group-containing monomer 1 to 10% by weight, and other monomer 90 to 9
By using a binder for a coating material for a vacuum coating machine, which comprises a polymer emulsion having a glass transition temperature of 10 to 80 ° C., obtained by emulsion polymerization of 9% by weight in an aqueous medium, and a coating material for a vacuum coating machine containing the same. The above problems have been solved.

Since a binder containing a polymer emulsion obtained by emulsion-polymerizing a monomer containing a predetermined amount of the hydrophilic group-containing monomer is used, the drying property is adjusted. Further, since the glass transition temperature of the polymer emulsion is set within a predetermined range,
The film forming property is improved. Therefore, it is possible to provide a coating material for a reduced pressure coating machine suitable for use in a reduced pressure coating machine in which a material to be coated is passed through a coating mist for coating.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. The binder for a coating material for a vacuum coating machine according to the present invention comprises a polymer emulsion obtained by emulsion-polymerizing a hydrophilic group-containing monomer and other monomers in an aqueous medium. Further, the coating material for a vacuum coating machine according to the present invention is a coating material containing the binder for a coating material for a vacuum coating machine.
The coating material for a vacuum coating machine according to the present invention can be prepared by adding a pigment, a filler, and if necessary, various compounding agents to the binder.

The hydrophilic group-containing monomer means a monomer containing a hydrophilic group, and the hydrophilic group includes a carboxyl group, a sulfonic acid group, an amino group, an amide group, an ammonium group and a hydroxyl group. Etc.

The above-mentioned hydrophilic group-containing monomer includes
The following can be given as examples. As the monomer having a carboxyl group, maleic acid, fumaric acid,
Examples thereof include crotonic acid, itaconic acid, acrylic acid and methacrylic acid. As the monomer having a sulfonic acid group,
Examples thereof include vinyl sulfonic acid and isoprene sulfonic acid.

Further, as the monomer having an amino group or an amide group, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N (meth) acrylic acid is used. -Monomethylaminoethyl, dimethylaminopropyl (meth) acrylamide, dimethylaminoethyl (meth) acrylamide and the like. As the monomer having an ammonium group,
Examples thereof include those obtained by quaternizing the amino group-containing monomer with acids. Examples of the monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, n-methylol (meth) acrylamide, and 4-hydroxybutyl (meth) acrylate.

Among these, acrylic acid, methacrylic acid, and 2-hydroxyethyl methacrylate are particularly preferable in terms of polymerizability and industrial availability.

The above-mentioned other monomer means a monomer other than the hydrophilic group-containing monomer and may be a polar group-containing monomer or a non-polar monomer. In particular, it is preferable to use both the polar group-containing monomer and the non-polar monomer in combination, from the viewpoints of miscibility with the compounding agent at the time of making the coating material, workability at the time of using the coating material and the like.

The polar group-containing monomer is a monomer containing a polar group, and the polar group includes an ester group,
Examples thereof include ether group, nitrile group and halogen.

Examples of the polar group-containing monomer include the following. As the monomer having an ester group, methyl (meth) acrylate,
Examples thereof include (meth) acrylic acid esters such as ethyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate.

Examples of the monomer having an ether group include methoxyethyl (meth) acrylate and butoxyethyl (meth) acrylate. Examples of the monomer having a nitrile group include (meth) acrylonitrile. Examples of the monomer having a halogen include vinyl chloride and vinylidene chloride. In addition, "(meta)
"Acrylic" means "acrylic or methacrylic".

Specific examples of the above-mentioned (meth) acrylic acid ester include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, t-butyl (meth) acrylate, and (meth). Iso-butyl acrylate, 2-ethylhexyl acrylate (meth), (meth)
Examples include octyl acrylate.

The average carbon number of the ester portion of the above (meth) acrylic acid ester is not particularly limited, but it is 2-8.
Is preferable and 4-6 is more preferable. If less than 2,
Water resistance may deteriorate. On the other hand, if it is greater than 8,
The polymerization reactivity tends to decrease.

Examples of the nonpolar monomer include olefinic monomers and vinyl aromatic monomers. Examples of the olefin-based monomer include ethylene, propylene and butene. Further, examples of the vinyl aromatic monomer include styrene, α-methylstyrene, vinyltoluene and the like.

The mixing ratio of the above-mentioned hydrophilic group-containing monomer and other monomer is, by weight ratio, hydrophilic group-containing monomer / other monomer = 1 to 10/99 to 90 ( However, the whole is 10
0) is preferable, and 2-6 / 98-94 (however, 100 is set as a whole) is preferable. If the amount of the hydrophilic group-containing monomer used is less than 1% by weight, the stability of the obtained emulsion may be reduced, and the compatibility with the compounding ingredients (pigment, filler, etc.) at the time of forming a coating material may be poor. It tends to get worse. On the other hand, if it is more than 10% by weight, water resistance and water permeability may deteriorate.

When both a polar group-containing monomer and a nonpolar monomer are used as the other monomer, the nonpolar monomer, the polar group-containing monomer and the hydrophilic group-containing monomer are used. The mixing ratio of the monomers is a weight ratio of nonpolar monomer / polar group-containing monomer / hydrophilic group-containing monomer = 1 to 60/35 to 85/1 to 1
0 (however, the whole is 100) is good, 3 to 50/4
0-80 / 2-6 (however, the whole is 100) is preferable. If the amount of the nonpolar monomer is less than 1% by weight, the alkali resistance of the coating film may deteriorate. On the other hand, if it is more than 60% by weight, the drying property of the coating film becomes too high, and the coating tends to stick. If the polar group-containing monomer is less than 35% by weight, the coating film may dry too quickly. On the other hand, if it is more than 85% by weight, the alkali resistance tends to deteriorate.

When styrene is used as the nonpolar monomer and (meth) acrylic acid ester is used as the polar group-containing monomer, styrene / (meth) acrylic acid ester / hydrophilic group-containing monomer = 1-60. / 35-85 / 1-10
(Weight ratio when the whole is 100) is preferable,
30/40 to 80/1 to 10 (weight ratio when the whole is 100) are preferable. If the content of styrene is less than 1% by weight, the water resistance and alkali resistance of the film may deteriorate. On the other hand, if it is more than 60% by weight, the drying property of the coating film may be too high. Further, if the content of the (meth) acrylic acid ester is less than 35% by weight, the drying property of the coating film may be too high. On the other hand, if it is more than 85% by weight, water resistance and alkali resistance may deteriorate.

The above-mentioned hydrophilic group-containing monomer and the other monomer are emulsion-polymerized in an aqueous medium to obtain a polymer emulsion. Examples of the aqueous medium at this time include water and a mixture of water and an organic solvent compatible with water (methanol, ethanol, acetone, etc.). Among these, it is preferable to use water from the viewpoint of economy and environment.

The emulsion polymerization is carried out in the aqueous medium in the presence of an emulsifier. Specific examples of emulsifiers include:
Cationic emulsifiers such as stearylamine hydrochloride, lauryltrimethylammonium chloride, trimethyloctadecylammonium chloride; potassium oleate, sodium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium alkylnaphthalenesulfonate, sodium dialkylsulfosuccinate, polyoxyethylene alkyl ether. Anionic emulsifiers such as sodium sulfate, sodium polyoxyethylene alkyl allyl ether sulfate, polyoxyethylene alkyl ether phosphate, polyoxyethylene alkyl allyl ether phosphate; polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene Oxypropylene block polymer,
Examples thereof include nonionic emulsifiers such as polyethylene glycol fatty acid ester and polyoxyethylene sorbitan fatty acid ester; and zwitterionic emulsifiers such as lauryl betaine and lauryl dimethylamine oxide.

Further, as the emulsifier, a surfactant having a radical-polymerizable carbon-carbon double bond (hereinafter referred to as "reactive emulsifier") may be used as the emulsifier for emulsion copolymerization. This reactive emulsifier is not physically adsorbed on the emulsion particles like an ordinary emulsifier, but is copolymerized at the time of polymerization and incorporated into a polymer chain. Therefore, the emulsion obtained by using the reactive emulsifier does not have a harmful effect such as a decrease in water resistance due to the presence of the emulsifier, and can form a film excellent in water resistance, alkali resistance, efflorescence resistance and the like. Further, an ordinary emulsifier is likely to be concentrated and unevenly distributed on the surface when a film is formed, whereas a reactive emulsifier is uniformly present in the film, and therefore the adhesion of the top coat film is also good.

Specific examples of the reactive emulsifier include:
Vinyl group, allyl group, propenyl group, acryloyl group,
A surfactant containing a radically polymerizable group having a carbon-carbon double bond such as a methacryloyl group is suitable, and various types of surfactants such as nonionic and anionic types are available. As such a reactive emulsifier, for example, a nonionic surfactant in which a radical polymerizable propenyl group is introduced into a hydrophobic group based on polyoxyethylene alkylphenyl ether as a basic structure, and a sulfate ester salt of polyoxyethylene alkylphenyl ether is used. Examples of the basic structure include anionic surfactants having a radically polymerizable propenyl group introduced into a hydrophobic group, sodium alkylallylsulfosuccinate, and the like. Specific examples of the reactive emulsifier include Aqualon HS-10 and Aqualon HS.
-20, Aqualon HS-1025, Aqualon RN-
20, Aqualon RN-30, Aqualon RN-50
(All are trademarks, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Eleminor JS-2 (trademark, manufactured by Sanyo Chemical Industry Co., Ltd.), Latemur S-180 (trademark, manufactured by Kao Corporation), and the like. .

The amount of the above emulsifier or reactive emulsifier used is
The amount is preferably 0.05 to 10% by weight, and more preferably 0.1 to 5% by weight, based on the total amount of the above monomers. As the polymerization initiator used for emulsion polymerization, a radical polymerization initiator generally used, for example, persulfate such as ammonium persulfate, potassium persulfate, sodium persulfate, 2,2′-azobisisobutyro Nitrile, 2,2'-azobis (2,2
4-dimethylvaleronitrile) and other azo-based polymerization initiators,
Examples thereof include peroxide type polymerization initiators such as benzoyl peroxide, lauroyl peroxide, hydrogen peroxide and t-butyl hydroperoxide. The amount of the above-mentioned polymerization initiator used is 0.05 to the total amount of the above-mentioned monomers.
10% by weight is preferable, and 0.1 to 5% by weight is preferable. The emulsion polymerization reaction is usually carried out at a temperature of about 60 to 100 ° C. and usually 2
It may be done for about 16 hours.

The glass transition temperature (hereinafter abbreviated as "Tg") of the copolymer in the polymer emulsion thus obtained is preferably 10 to 80 ° C, and more preferably 10 to 45 ° C. If the temperature is lower than 10 ° C, blocking after applying the obtained coating material for a vacuum coating machine may be deteriorated. on the other hand,
If it is higher than 80 ° C, the water permeability of the coating film after coating the obtained coating composition for a vacuum coating machine may be lowered.

The polymer emulsion thus obtained contains other additives such as defoaming agents, viscosity modifiers, anionic surfactants, and cationic surfactants within a range not impairing the object of the present invention. Activators, nonionic surfactants, pigments, fillers, antioxidants and the like can be added.

The liquid containing the above-mentioned polymer emulsion can be effectively used as a coating material, particularly as a coating material used in a vacuum coating machine in which a material to be coated is passed through a coating mist for coating.

[0030]

EXAMPLES The present invention will be described in more detail below with reference to examples. In the following examples and comparative examples, the raw materials used and the tests and evaluation methods performed will be described.

<Raw material monomer> Methacrylic acid: Reagent special grade manufactured by Wako Pure Chemical Industries, Ltd.
Abbreviated as “MAA”. ) Styrene: Wako Pure Chemical Industries, Ltd. special grade reagent (hereinafter "S
It is abbreviated as "M".・ Methyl methacrylate: Kanto Chemical Co., Ltd. special grade reagent (hereinafter abbreviated as “MMA”) 2-Ethylhexyl acrylate: Mitsubishi Chemical Co., Ltd. (hereinafter abbreviated as “2EHA”)

<Viscosity> Using a BM type rotational viscometer manufactured by Tokimec Co., Ltd., at a temperature of 25.degree. 1 rotor, 60r
It was measured in pm.

<Glass transition temperature (Tg)> A film obtained by drying the obtained polymer emulsion at 80 ° C. for 24 hours was analyzed by using a differential scanning calorimeter (DSC220C manufactured by Seiko Denshi Kogyo KK). Measured.

<Peeling> The obtained polymer emulsion was applied to a vacuum coating machine (SEC coating machine manufactured by Orwell Co., Ltd.) 2
The state of the resin-adhered skin adhered to the exit of the coating booth during the time circulation was evaluated according to the following criteria. ◯: Adhesion with a thickness of less than 1.0 mm Δ: Adhesion with a thickness of 1.0 mm or more and less than 2.0 mm ×: Adhesion with a thickness of 2.0 mm or more

<Foaming coating> The obtained polymer emulsion was used to coat an inorganic board (siding board for building materials (using cement binder)) with a vacuum coating machine (SEC coating machine manufactured by Orwell Co., Ltd.). The bubbles in the paint film on the painted surface were confirmed with a louver. The observation results were evaluated according to the following criteria. A: Almost no bubbles are seen B: Small bubbles are confirmed C: Large bubbles are confirmed

<Water permeability> The obtained polymer emulsion was applied onto an inorganic board (a siding board for building materials (using cement binder)) so as to have a thickness of 35 g / m ² (dry basis), and 100 ° C x 5 The amount of water permeation after 24 hours was measured in 0.1 ml units on the dried test piece by the burette method of JIS A6909 water permeation test B method.

<Efflorescence resistance> 30 ° C., humidity 9
In a 0% constant temperature and humidity chamber, apply the obtained emulsion to a pallet containing water and apply it to the same inorganic board as above.
A film dried at 0 ° C. was put vertically, the part of 3 cm from the edge of the inorganic board was soaked in water, and left for 10 days, and then a 0.5% ethanol solution of thymol blue was applied. A portion where efflorescence is generated becomes alkaline and discolors to blue, and a portion where efflorescence is not generated becomes yellow. Therefore, the area of the yellow portion was determined, and the efflorescence resistance was evaluated according to the following criteria. ◯: Area of yellow part is 80% or more and 100% or less of total Δ: Area of yellow part is 50% or more and 80% or less of total ×: Area of yellow part is less than 50% of total

(Examples 1 to 3 and Comparative Example 1) A four-necked flask equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser was placed in an anionic reactive emulsifier (Aquacron HS-1).
0, manufactured by Daiichi Kogyo Seiyaku Co., Ltd. and 1 part by weight of water and 100 parts by weight of water were added, and the temperature was raised to 75 ° C. To this, 0.3 parts by weight of potassium persulfate as a water-soluble polymerization initiator was added, and various monomer raw materials having the composition (parts by weight) shown in Table 1 were put into a dropping funnel and stirred for 3 hours. Then, the polymerization reaction was carried out by dropping. Further, the temperature was raised to 80 ° C., the aging completion reaction was performed for 2 hours, and the mixture was cooled to room temperature and stirred. Then, 25% ammonia water was added dropwise to adjust the pH to 7 to 7.5, and an appropriate amount of water was added to prepare a polymer emulsion having a solid content of 35%. The above-mentioned evaluation test was conducted using the obtained polymer emulsion. The results are shown in Table 1.

[0039]

[Table 1]

[0040]

EFFECT OF THE INVENTION The paint for a vacuum coating machine according to the present invention comprises
Since a binder containing a polymer emulsion obtained by emulsion-polymerizing a monomer containing a predetermined amount of the hydrophilic group-containing monomer is used, the drying property is improved. Further, since the glass transition temperature of the polymer emulsion is set within the predetermined range, the coatability is improved. Therefore, it is possible to provide a coating material for a reduced pressure coating machine suitable for use in a reduced pressure coating machine in which a material to be coated is passed through a coating mist for coating.

Continued front page    F term (reference) 4J038 CB001 CB002 CB031 CB032                       CB091 CB092 CB121 CB122                       CC001 CC002 CC021 CC022                       CC061 CC062 CC081 CC082                       CG141 CG142 CH081 CH082                       GA03 GA06 GA08 GA09 GA13                       MA13

Claims (10)

[Claims] 1. A glass transition temperature of 10 to 80 ° C. obtained by emulsion polymerization of 1 to 10% by weight of a hydrophilic group-containing monomer and 90 to 99% by weight of another monomer in an aqueous medium. A binder for paints for vacuum coating machines, which consists of a polymer emulsion. 2. The binder for a coating material for a vacuum coating machine according to claim 1, wherein the hydrophilic group is any one of a carboxyl group, a sulfonic acid group, an amino group, an amide group, an ammonium group and a hydroxyl group. 3. The hydrophilic group-containing monomer is acrylic acid,
The binder for a coating material for a vacuum coating machine according to claim 1, which is either methacrylic acid or 2-hydroxyethyl methacrylate. 4. The coating material for a vacuum coating machine according to claim 1, wherein the other monomer contains both a polar group-containing monomer and a nonpolar monomer. binder. 5. The polar group is an ester group, an ether group,
The binder for paint for a vacuum coating machine according to claim 4, which is either a nitrile group or a halogen. 6. The binder for a coating material for a vacuum coating machine according to claim 4, wherein the polar group-containing monomer is a (meth) acrylic acid ester. 7. The binder for a coating material for a vacuum coating machine according to claim 4, wherein the non-polar monomer is an olefinic monomer or a vinyl aromatic monomer. 8. The other monomer contains styrene and (meth) acrylic acid ester, and the content ratio (weight ratio) of styrene, (meth) acrylic acid ester and hydrophilic group-containing monomer is , Styrene / (meth) acrylic acid ester / monomer containing hydrophilic group, 1-60 / 35-85 / 1
The binder for a coating material for a vacuum coating machine according to claim 4, wherein the binder is 10 to 10 (the total is 100). 9. The binder for a coating material for a vacuum coating machine according to claim 6 or 8, wherein the ester portion of the (meth) acrylic acid ester has an average carbon number of 2 to 8. 10. A paint for a vacuum coating machine, which comprises the binder for a paint for a vacuum coating machine according to any one of claims 1 to 9.