JPS5836683A - Painting method - Google Patents

Abstract

PURPOSE:To shorten a drying time and to form resin films efficiently in the stage of painting a high polymer latex on a base material by coating paint liquid consisting essentially of materials which flocculate the latex in combination thereon. CONSTITUTION:In the stage of coating a high polymer latex on a base material, paint liquid consisting essentially of the materials which flocculate the latex is coated before or after the coating of the latex or simultaneously. For the high polymer latex, ordinary general purpose org. high polymer latexes of vinyl acetate, (meth)acrylic, styrene, etc. are used along or in combination. Porous materials such as concrete mortar, asbestos slate and the like are effective as the base material. There are, for example, polyaluminum chloride, ferrous sulfate, sodium aluminate, etc. as the materials for flocculating the high polymer latex and it is preferable to coat the same usually as an aq. soln. of about 10wt% and to coat the same at about 50-300g/m<2>.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for coating polymer latex. For more details, please refer to Polymer Latex tt#By applying a coating liquid mainly composed of a substance that coagulates the latex, the energy required for drying can be reduced, and a resin film can be efficiently formed on the base material. It relates to a method of forming.

Recently, polymer latex has been increasingly used in various coating fields. This is a pollution issue because solvent t is rarely used.

This is because it is advantageous from a sanitary and resource saving perspective, as it reduces dust and has a higher molecular weight than ordinary solution-type resins, and the resulting coating film is strong and has excellent resistance to various conditions.

Furthermore, since it is in a dispersed state, it can be used in the form of low viscosity and high solid content, and is also advantageous in terms of coating workability.

On the other hand, there is also an inherent drawback because the volatile component is water.
The biggest problem is that a large amount of heat is required for drying.

Methods to improve drying efficiency when using polymer latex have been studied for some time, and changes have been made to drying equipment such as using high-temperature, short-time processing in hot air open, and using microwaves. ing. However, these changes are not only disadvantageous in terms of cost, but also not necessarily advantageous in terms of energy.

In addition, from the viewpoint of the composition of polymer latex, it is possible to make the resin composition harder and make the apparent drying speed faster, but it is not possible to expect a significant improvement, and there are significant restrictions in terms of the physical properties of the coating film. .

The inventors of the present invention have conducted extensive research on methods for improving drying properties using polymer latex, and have found that by applying a coating liquid containing a substance that causes polymer latex to coagulate.

My friend found it to be significantly improved.

That is, when coating a polymer latex on a base material, the present invention provides a coating solution 'Y' whose living body is a substance that causes the latex to coagulate, at least once before, after, or simultaneously with the latex coating. This is the way to do it.

The polymer latex used in the present invention is not particularly limited, but two common general-purpose organic polymer latexes such as vinegar-aged vinyl, (meth)acrylic (acrylic or methacrylic), and styrene can be used alone or in combination. Especially (meth)acrylic polymer latex can be used.

It can be used for a variety of purposes because of its good weather resistance, low resistance to heat yellowing, and the ease of adjusting the hardness of the film obtained from latex.

In this case, as the main monomer, in addition to various acrylates and methacrylates, those having functional groups are used, and styrene/-acrylonitrile, I22 vinyl acetate, etc. can also be used in small amounts. These organic polymer latexes are synthesized by a conventional emulsion polymerization method. The emulsifier used in this case is not necessarily limited, but anionic emulsifier 1 such as sulfate ester salt of higher alcohol, alkylaryl sulfone limited salt, sulfate ester salt of phoroxyethylene alkylphenyl ether, alkyl succinic acid salt etc.
When used in the present invention, the effect becomes even more like a married woman. In addition, when using a polymer latex having carboxyl groups, a coating liquid mainly containing a substance that causes the latex to coagulate is applied, so that the sharpening effect becomes more pronounced and is more effective. As a method for introducing a carboxyl group, usually radically polymerizable unsaturated carboxylic acid is used, such as acrylic carboxylic acid,
Methacrylic acid, maleic acid monoalkyl ester, etc. are copolymerized with other monomers during emulsion polymerization.

Nine polymer latexes using anionic emulsifiers have the disadvantage that the resulting coating film has poor water resistance. In order to reduce this drawback, it is necessary to reduce the amount of anionic emulsifier used.

In this case, there is a contradiction that stability during emulsion polymerization deteriorates. This contradiction can be resolved by using colloidal silica during emulsion polymerization! During emulsion polymerization, a polymer latex that is stable and provides a fishing film with good water resistance is obtained.

Snowtex 20 is a colloidal silica. -3
0. -C.

-N (both manufactured by Nichichi Kagaku), Ludtux H8
, -L8. -AM, -'IL -As (both manufactured by Bonn, Deutsche, USA), etc. can be used.

Further, as the polymer latex, in addition to the organic type described above, a latex in which an inorganic polymer such as silicon is dispersed in water can also be used depending on the purpose.

The substrate to which the coating method of the present invention is applied is as follows.

There are no particular restrictions on materials that can be coated with polymer latex, such as concrete mortar, asbestos slate, silicon +
a It is more effective when using porous substrates such as two calcium plates and two cardboards. Especially - before painting polymeric latex.

Two features of the present invention become more prominent when a coating liquid containing a substance that coagulates the latex is applied. According to this method, when coating the polymer latex, it comes into contact with a substance that aggregates the latex that has been coated in advance,
It aggregates in a very short time to form a film. As a result, the yield of the surface layer that prevents the penetration of the polymer latex into the base material is improved, and the gloss and color development of the coated surface are improved.

When using asbestos slate, mortar, or siliceous calcium board as a base material, in addition to obtaining the characteristics of the porous base material described above, you can also expect a coagulation effect due to multivalent ions such as calcium contained in the slate. , is even more effective.

Asbestos slate is usually made from a slurry of asbestos, cement, water, etc. through a papermaking process. Since polymer latex is an aqueous system using water as a dispersion medium, it can be coated even on wet substrates, and in the case of asbestos slate, it can be coated during the papermaking process, that is, in a wet state.

According to the coating method of the present invention, since the coated polymer latex dries very quickly, there is no need to make major changes to the existing papermaking process, which is advantageous in terms of equipment. In other words, the coating method of the present invention is more effective even in applications where drying equipment cannot be used.

This method of painting in a wet state is used not only in the production of asbestos slate, but also in papermaking, such as paper and corrugated board.11. It can also be applied to mutual papermaking processes.

Any flocculant used for wastewater treatment etc. can be used as a substance that flocculates polymer latex. However, when using the polymer latex used in the present invention, especially an anionic emulsifier, inorganic cationic flocculating agent can be used. agent is the most effective. Examples of inorganic cationic flocculants include polyaluminum chloride, ferrous sulfate, ferric sulfate, ferric chloride, sulfate fulminium, and sodium chloride for aluminum, either alone or in combination, or with other flocculants. used in combination. These inorganic cationic flocculants are inexpensive and advantageous in that respect as well. When used in the present invention, it is usually preferable to apply the coating in the form of a 10% by weight aqueous solution. Of course, other types of coating fluids may also be used.

The coating liquid may contain additives.

There are no particular limitations on the method for applying the coating liquid, which is mainly composed of polymer latex and a substance that coagulates the latex, and roll coating, spray coating, air knife coating, curtain coating, no(-coating), etc. can be used. can be applied before, after, or at the same time, or even in a combination of two or more before, after, and at the same time.Note that simultaneously means two or more spray guns, etc. Three or more are used, and the polymer latex and the coating liquid are applied to the base material simultaneously from separate spray guns.There is no particular restriction on the coating quality of the coating liquid.
Depending on the type of substrate, the coating is usually applied at a rate of about 50 to 300 f/ze.

Although the coating method according to the invention can be used alone, conventional drying equipment 2, for example hot air open.

You can dry faster by using a microwave dryer and an infrared dryer together.

tg, polymer latex can be colored with a color dispersion using a water-soluble resin or t! It can also be applied as a mixture to which solvent A is added.

The present invention uses a physically stable aqueous dispersion of polymer latex T, which is destabilized with a flocculant.

This is a method of achieving the desired effect by aggregating them. Conventionally, 2 For example, in urethane paints, -
A method is being considered in which the OH component and -NCO component are separated, but in this method the painter is separated in order to prevent gelation due to the reaction between the pOH group and the NCO group. The invention is clearly KJ! It is what it is. It was.

The reaction between OH and NCO groups is a chemical reaction that creates covalent bonds, so it takes a long time! Therefore, it is unsuitable for the purpose of accelerating the drying of paint.

Although it is not clear why the drying speed is faster with the coating method using 1JlK, water separates from the resin component due to coagulation of the polymer latex.

Because of the film, it appears to be negative when evaluated by finger touch.
It is possible that it will dry faster.

As described above, the present invention not only speeds up drying when coating polymer latex, but also prevents its penetration when using a porous substrate.

It is a coating method with wide applicability, such as achieving a high yield on the surface of the substrate.Furthermore, it is a simple process and does not require new drying equipment.

It has great industrial utility value.

Next, one embodiment of the present invention will be described.

"Part r" and "Chi" respectively indicate parts by weight 2 weight SY.

Reference example Synthesis method table for (meth)acrylic polymer latex! It was synthesized using a conventional emulsion polymerization method using the seven-mer composition and emulsifier composition shown below. The polymerization initiator used was a redox system consisting of a combination of persulfated ammonium, bisulfite, and sodium. Both use 2 units of light per monomer. Polymerization 11 was carried out at 60 to 70°C for 3 to 4 hours (all examples had a solid content of 40%).

Viscosity: 500 cps or less).

Table ■ *: The amount of emulsifier is the tsv used for the total amount of monomers.
show.

Uses nine base materials 1. Asbestos slate Portland Seven Men) 10.0 parts 1 asbestos 15 parts.

The paper was mixed with water 150011%'ζ mixer, vacuum suctioned, and cured at room temperature for 20 days.

2. Asbestos slate of W1 Junsha 1.K? Ym was used at the stage before curing.

3 Porous paper - er39g - paper (asotld) w-1: used as is - Test method - 1EII7F method (base material is asbestos slate) In the case of paper, use Percoater IIi method and polymer latex (]!l[
Loading amount: 154) f/s/) and 11111 (coating amount: 150 f/s/) mainly consisting of the latex agglomerating substance.
was painted.

Determination of O dryness The time until the tack disappears was measured by touch at room temperature.

O Coating order execution 41A1-7 is a coating liquid v mainly containing a substance that coagulates the latex before applying the polymer latex vW1i.
Examples 8 to 10 were painted in reverse order to the above.

Examples 1-io, Comparative Examples 1-4 The results under each condition are shown in t'*u.

Note-1) The coated products obtained in Examples 4 and 10 were superior in water resistance (immersed in water at 25°C for 3 hours) compared to the coated products obtained in Examples 2 and 8, respectively. -2) **Organizations obtained in Examples 2 and 4 were obtained in Examples 8 and 10, respectively, and 7ti! Glossier than E accessories (Gloss meter manufactured by Murakami Color Co., Ltd.)

(measured at 60°C) was excellent.

The *iui method shown in the above example was found to have a significant effect on drying performance compared to the comparative example.

Table ■

Claims (1)

[Claims] l When coating a base material with polymer latex. The latex? A coating method comprising applying a coating liquid mainly containing a substance that causes coagulation before, after, or at the same time as coating the latex. 2. The coating method according to claim 1, which uses a polymer latex polymerized mainly from monomers selected from acrylic monomers and methacrylic monomers. 3. The coating method according to claim 1 or 2, which uses a polymer latex using an anionic emulsifier. 4. A coating method using polymer latex using colloidal silica as claimed in claim @3. 5. The coating method according to any one of claims 1 to 4, which uses an organic polymer latex containing a carboxyl group. 6. As a substance that aggregates the polymer latex. Claim 3 using an inorganic cationic flocculant
Coating method described in Section 4 or Section 4. 7. The coating method according to any one of claims 1 to 6, wherein a porous base material is used as the base material. 8. The coating method according to claim 7, wherein one selected from asbestos slay F2 mortar and all calcium board is used as the base material. 9. The coating method according to claim 8, wherein one selected from wet asbestos slate, mortar, and calcium silicate board is used as the base material. 1G The coating method according to any one of claims 6 to 9, wherein before coating the polymer latex, a coating liquid Cm mainly containing a substance that coagulates the latex is applied.