JPS586746B2 - Polyurethane emulsion material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reactive urethane emulsion coating agent among coating agents for applying a urethane resin film.

Conventional urethane emulsion coating agents are aqueous dispersions of urethane resins, and in order to provide dispersibility, hydrophilic groups such as carboxyl groups or sulfone groups are introduced into the structure of the urethane resin, or chain length is extended. An amino alcohol is introduced as an agent and quaternization is carried out using a quaternization agent.

Since these urethane emulsions contain hydrophilic groups, the resulting films have poor water resistance and solvent resistance, and although they are used as adhesives or fiber treatment agents, they are not satisfactory as coating agents. There wasn't.

The present invention was researched and invented in order to improve the drawbacks, and it is a coating agent containing an incyanate having a blocked NGO group of two or more functional groups and a polyol having two or more active hydrogens or an amine. The components are dissolved in an organic solvent and then emulsified and dispersed in water, and it is not an emulsion of polymerized resin like conventional ones, but an emulsion of something that reacts to produce urethane resin.
When baked after painting, the block incyanate decomposes and regenerated NGO groups react with active hydrogen to produce urethane resin and form a film, so it is necessary to contain hydrophilic groups in the resin component. There is no.

Therefore, the urethane resin film obtained by the coating agent of the present invention has excellent water resistance and solvent resistance, and since it contains an organic solvent (
(20% or less) The paint film has good flow and can be coated with a glossy finish.

Furthermore, in order to apply the coating agent of the present invention to the surface of plastics, a coating agent with good paintability can be obtained by adding a wetting agent to the ingredients.

Furthermore, when the coating agent of the present invention is used as a top coat agent for resin coating of glass pins, etc., and in order to prevent odor from forming on the resin film, it is effective to achieve the purpose by using a polyol with an OH equivalent of 250 or less. Furthermore, when applying a label or the like to the coating surface, in order to improve the adhesion, a cellulose derivative can be added to the coating agent component to achieve this purpose.

That is, by applying this top coat agent, it is possible to improve the label adhesion properties of resin-coated glass pins, etc., and to obtain resin-coated bottles that have a long service life and are free from odor caused by washing bottles and the like.

The blocked isocyanate used in the present invention is one in which the isocyanate group is blocked with phenol or ε-caglolactam, and examples of the isocyanate include tolylene diisocyanate, hexamethylene diisocyanate,
Single substances such as xylylene diisocyanate and isophorone diisocyanate, or these together with trimethylolpropane,
For 1,4-butanediol, triethanolamine, polytetramethylene glycol, ethylene glycol, diethylene glycol, and bisphenol A, a prepolymer with NCO terminals reacted with hexamethylene diamine or the like is used.

As the polyol used in the present invention, polyester polyol polytetramethylene glycol ether, propylene glycol, polyfunctional polyether, etc. can be used.

Triol, methyl ethyl ketone, methoxybutyl acetate, or the like is used as the organic solvent for dissolving the coating agent components, but the proportion thereof should be 20% or less of the total composition and used in an amount that does not cause pollution.

Nonionic, anionic or cationic activators are used for emulsification and dispersion in water, and fluorine or silicone dispersants are used as wetting agents to improve paintability on plastics. Nitrocellulose, acetylcellulose, alkylcellulose, or the like is used as a cellulose derivative for improving label sticking properties.

Next, examples will be shown. In the examples, "parts" in the amounts shown are parts by weight.

After reacting (1) and (2) at 100°C for 3 hours, 50
Cool to ℃ and add (3), (4), and (5).
Stir.

Add a surfactant (Kao Emulgen 935) to 100 parts of the solution.
After stirring, 150 parts of water was gradually added while stirring to emulsify and obtain an emulsion coating.

This coating agent was applied to a tin plate and heated at 180° C. for 10 minutes to obtain a transparent, glossy coating film with excellent water resistance and solvent resistance.

(1), (2), (mix together and react at 100℃ for 3 hours (to block half of the NCO groups in (1)) then add (3) and react at 100℃ for 3 hours Seshime (react half of the polyol with the remaining NCO groups) and cool to 50°C (
Add 4), (5), and (6) and stir.

To 100 parts of the liquid, 1 part of a surfactant (same as in Example 1, but mixing ratio 1:1) was added, stirred at high speed, and 150 parts of water was gradually added to emulsify to obtain an emulsion coating agent.

This coating agent was applied as a top coat to the urethane resin surface of a glass bottle and heated at 180° C. for 10 minutes to obtain a uniform and glossy top coat film.

This coating agent has good paintability on urethane resin surfaces, it is easy to attach labels, etc. to the resulting film, and there is no odor when collecting and cleaning bottles, and the coating has a long service life. I was able to get a bottle.

Add 2 parts of surfactant (same as Example 2) to 100 parts of a mixed solution of (1), (2), and (3), stir and
50 parts were gradually added and emulsified, and a black pigment treated with an anionic activator (WS Color, manufactured by Toyo Ink) was added to obtain a black emulsion coating agent.

This was coated on a copper plate and baked at 200° C. for 30 minutes to obtain a glossy black coating with excellent water and solvent resistance.

This coating is tough and flexible, making it hard to scratch the surface.
It also has an excellent property of adapting well to processing such as bending copper plates.

Example 4 (1), (2), and (6) were mixed and reacted at 100°C for 3 hours (to block 2/3 of the NGO groups), and then (3)
) was further reacted at 100° C. for 3 hours (to react polyol 173 with the remaining NGO groups), the mixture was cooled, and (4) and (5) were added and mixed well.

An activator (same as in Example 2) was added to 100 parts of this liquid, and while stirring, 150 parts of water was gradually added to emulsify to obtain an emulsion coating agent.

This paint also has good paintability on plastic surfaces.
Baking for 10 minutes at 50°C or 10 minutes at 240°C gives a strong film with excellent gloss and good water and solvent resistance.

Claims (1)

[Claims] 1. A coating component containing a blocked incyanate having a difunctional or higher NCO group and a polyol or amine having two or more active hydrogens is dissolved in an organic solvent and then emulsified and dispersed in water. A reactive urethane emulsion coating agent.