JPS60197720A - Aqueous polyurethane resin dispersion - Google Patents

Abstract

PURPOSE:An aqueous polyurethane resin dispersion excellent in storage stability, warm water resistance of a film, etc., and suitable as an adhesive or the like, obtained by dissolving a cationic water-soluble radical initiator in a specified aqueous polyurethane resin dispersion. CONSTITUTION:Polybutadiene-polyol of an MW of 500-5,000 is reacted with an aliphatic diisocyanate (e.g., hexamethylene diisocyanate) to obtain an NCO-terminated prepolymer. A diol having at least one tert. amino group (e.g., N-methyldiethanolamine) is reacted with the reaction mixture and a quaternizing agent (e.g., dimethyl sulfate) is reacted with this reaction mixture. Water is then added to the final reaction mixture to obtain an aqueous polyurethane resin dispersion. A cationic water-soluble radical initiator [e.g., 2,2'-azobis(2-amidinopropane) hydrochloride] is dissolved in this aqueous dispersion to obtain the titled dispersion.

Description

[Detailed description of the invention] The present invention relates to polyurethane aqueous resin dispersions.

Polyurethane emulsions are used for various purposes, but when they are used as adhesives, for example, there is a problem with water-resistant adhesive strength, which has the drawback of being significantly lower than normal adhesive strength. In order to prevent this drawback, blocked isocyanates are used or urethane is crosslinked with melamine, but in the former case, crosslinking does not occur unless the temperature is about 140°C, or the blocking agent remains and has an adverse effect. In the latter case, there are problems of pungent odor and toxicity due to formalin.

An object of the present invention is to provide a polyurethane aqueous resin/dispersion that provides a film with excellent water resistance, particularly hot water resistance, and has excellent storage stability.

The present invention uses a cationic water-soluble radical initiator in an aqueous dispersion obtained from a polybutadiene polyol having a molecular weight of 1,500 to 5,000, an aliphatic diisocyanate, a diol having at least one tertiary amine 7 group, and a quaternizing agent. It relates to a polyurethane aqueous resin dispersion in which

In the present invention, examples of the polybutadiene polyol having a molecular weight of 500 to 5000 include Po1y manufactured by Idemitsu Petrochemical Co., Ltd.
bd R-45HT, R-45M, R-45D1
Polybutadiene polyol G-1000 manufactured by Nippon Soda,
Examples include G-2000 and G-3000.

As the diisocyanate of the present invention, various known bifunctional aliphatic (including alicyclic) isocyanates in the field of polyurethane production can be used, such as hexamethylene diisocyanate (HDI), isophorone diisocyanate) (IPDI) ), 4,4''-dicyclohexylmethane diisocyanate (IIMDI), lysine diisocyanate (LDI), and the like.

In the present invention, examples of diols having at least one tertiary amine 7 group include N-methylgetanolamine, N-ethylgetanolamine, N-butylgetanolamine, N-phenylnoethanolamine, N, N
-dihydroxyethyl-repiperazine, N,N-dimethylamino-2,2-bishydroxymethylethylamine, and the like.

Examples of quaternizing agents include dialkyl sulfates such as dimethyl sulfate and diethyl sulfate; halogenated hydrocarbons such as methyl chloride, methyl iodide, ethyl bromide, and benzyl chloride; organic acids such as acetic acid, propionic acid, and monochloroacetic acid; Various quaternizing agents can be used, such as inorganic acids such as hydroiodic acid, hydrobromic acid, hydrochloric acid, and perchloric acid.

Furthermore, in the present invention, a conventional chain extender can also be used if necessary. As a chain extender, for example, a molecular weight of 5
00 or less 2-6 functional polyol and molecular weight 500
The following diamines having 7 primary or secondary terminal amide groups are mentioned. Suitable chain extenders include (a) ethylene glycol, diethylene glycol, propylene glycol, nopropylene glycol, butanediol, hexanediol, glycerin, trimethylolpropane, pentaerythritol, sorbitol,
Polyols such as 1,4-cyclohexanediol, 1゜4-cyclohexane dimetatool, and xylylene glycol (b) Diamines such as hydrazine, ethylenecyamine, tetramethylenediamine, hexamethylenediamine, and 1,4-cyclohexanediamine (C) Alkanolamines such as ethanolamine, jetanolamine, and triethanolamine (d) Hydroquinone, pyrogallol, 4.4-4-sopropylidene diphenol, aniline, and the above polyols, diamines, and alkanolamines Molecular weight 500 obtained by adding propylene oxide and/or ethylene oxide in any order
Examples include the following polyols.

In the present invention, each component may be appropriately determined within a wide range depending on the desired aqueous resin dispersion, but for example, polybutadiene polyol, diol having at least one tertiary amino group, and chain extender may contain The chemical equivalence ratio of the active hydrogen group contained in the active hydrogen group and the NCO group of the diisocyanate is 0.
．． The reaction should be carried out within a range of 9 to 1.4, preferably 0.95 to 1.1. Further, in the present invention, an inert solvent that does not react with NCO groups can be used, and if necessary, the solvent can be recovered by distillation. Furthermore, known urethanization catalysts, aqueous antifoaming agents to suppress foaming during emulsification (e.g., Toray Silicone, 5N-5512, San Nopco, SN Deformer 113.432, etc.), weather resistance, It is also optional to use an anti-yellowing agent (eg, hindered phenol group, hindered amine type, etc.) to impart heat discoloration resistance.

Examples of the above-mentioned solvents include ketones such as acetone and methyl ethyl ketone, esters such as ethyl acetate and methyl propionate, ethers such as dioxane, tetrahydro-7rane, and Serisolve acetate, and dimethylformamide, dimethylacetamide, dimethyl sulfoxide, and hexane. Methylphosphoric triamide, N-methyl biaridone, etc. may be mentioned, and these solvents may be used at any stage of the reaction of the present invention.

The aqueous polyurethane resin dispersion of the present invention can be produced by various methods, such as a one-shot method or a prepolymer method. In the prepolymer method, for example, a polybutadiene polyol and a diisocyanate are reacted to form an NCO-terminated prepolymer, which is then reacted with a diol having at least one tertiary amino group and optionally a chain extender. The quaternization reaction can be carried out during or after the polymerization of the polyurethane. After cooling the obtained polymer, water is added with vigorous stirring to obtain a milky white emulsion. Prepolymerization reaction is generally preferably carried out at a temperature of 60 to 130°C. Further, the quaternization reaction is generally preferably carried out at a temperature of 40 to 100°C. Further, after emulsification, the solvent is distilled off under normal pressure or reduced pressure to obtain a solvent-free aqueous dispersion of the polyurethane resin.

In the present invention, a cationic water-soluble radical initiator is added to the polyurethane aqueous dispersion obtained above to form a film, and then heated to crosslink the remaining double bonds, thereby improving film hardness and water resistance. Improved. A representative example of this radical initiator is 2,2'-azobis(2-amidinopropane) hydrochloride, which is usually about 0.0% relative to the polyurethane (solid content).
05-5%, &F*L< is preferably dissolved at about 0.1-1%.

The aqueous polyurethane dispersion of the present invention can be used in various conventional fields of use of aqueous polyurethane dispersions, such as adhesives, paints, glass fiber sizing agents, fiber treatment agents, etc.

The present invention will be explained below with reference to Examples.

Example 1 (11) Polybutadiene 140g Polyol G-2000 (b) IPD I 48.6g (c) N-Methyldieta to,ognolamine (d) Ethylene glycol 3.5g (e) Dimethyl sulfate 8.8g (f) 250 g of methyl ethyl ketone (in HE)
Put (a) and (b) into a 100O separable 7 flask and react at 100-120°C for 1 hour. After cooling to 70°C, m, (e), and (d) were added and reacted at 70-80°C for 1 hour, and further 0.05 g of dibutyltinsilaure was added and reacted at 70-80°C for 4 hours. After cooling to 50℃ (
Add e) and react at 50-60°C for 60 minutes.

After adding 487 g of water, NEK is distilled off to obtain an emulsion. 1.4 g of 2.2''-7zobis(2-amidinopropane) hydrochloride is added to this solution and mixed.

The resulting aqueous resin dispersion had a viscosity of 120 cps at 25°C.

The pH was 6.8 and the solid content was 30%.

Comparative Example 1 Volipta Ciemborio-1k G 2QOO (140g
An aqueous polyurethane resin dispersion was obtained in the same manner as in Example 1, except that 140 g of Tu'borane 4010) was used in polybutylene adipate glycol instead of ).

The resulting aqueous resin dispersion had a viscosity of 75 cps at 25°C, p
H6.1, solid content 30%.

Comparative Example 2 A polyurethane aqueous resin dispersion was obtained in the same manner as in Example 1 except that 2.2'-azobis(2-amidinopropane) hydrochloride was not used.

Coating film test The emulsions of Example 1, Comparative Example 1, and Comparative Example 2 were applied on an iron plate with a thickness of 1+ am, and after drying at 80'C for 2 hours,
Baking was performed at 65° C. for 30 minutes to obtain a coating film with a thickness of SO, O3III1. The pencil hardness (normal hardness) of this coating film is 40”
Table 1 shows the hardness and coating condition of sample C after being immersed in hot water for 3 days.

Table 1 Normal state - Agitated in the gate Ω 1 - Hardness Hardness state.

Example 1: No HH change Comparative example 2 38 3B No change above)

Claims (3)

[Claims] (1) Polybutadiene polyol with a molecular weight of 500 to 5,000, aliphatic diisocyanate, a small amount (both one tertiary
A polyurethane water-based resin dispersion in which a cationic water-soluble radical initiator is dissolved in an aqueous dispersion obtained from a diol having 7-class amine groups and a quaternizing agent. (2) The aqueous polyurethane resin dispersion according to claim 1, which is obtained by quaternizing polyurethane in an organic solvent during or after polymerization, and then adding water and a radical initiator. (3) Claim 2 obtained by distilling off the organic solvent
The polyurethane aqueous resin dispersion described in .