JPS587422A - Aqueous dispersion of polyurethane - Google Patents

Abstract

PURPOSE:To prepare the titled aqueous dispersion having excellent resistance to hydrolysis, by reacting a fatty acid oxyalkyl ester, a polyether polyol and a polyisocyanate in the presence of an oxycarboxylic acid, neutralizing the produced resin with an amine, and dispersing the product in water. CONSTITUTION:The objective aqueous dispersion is prepared by (1) reacting a mixture of (A) 100pts.wt. of a fatty acid oxyalkyl ester obtained by the ester exchange of (i) 100pts.wt. of an oil having an iodine value of >=100 (e.g. linseed oil) and/or its fatty acid and (ii) 30-500pts.wt. of a polyhydric alcohol, (B) 1- 70pts.wt. of a polyether polyol having a molecular weight of 1,000-20,000, and (C) 5-80pts.wt. of an oxycarboxylic acid of formula (R is alkyl, etc.; A is -CnH2n+1-, etc.; the carbon number in the molecule is 10-20), with (D) a polyisocyanate, (2)neutralizing the resultant polyurethane resin having a molecular weight of 1,500-50,000 with an amin, and (3) dispersing the product in water. EFFECT:Excellent coating film properties, and safety.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to polyurethane water drinks, and more particularly to polyurethane aqueous dispersions having hydrolysis resistance, agglomeration resistance, and miscibility stability.

While organic solvent-based paints, which have been the mainstream in the past, run the risk of fires and air pollution due to the solvent, water-based paints do not pose these risks and also help conserve resources.
It has become a widely used trap.

However, conventional alkyd resins that have been water-solubilized or water-dispersed (hereinafter referred to as water-dispersed) are made into polymers by repeating esterification bonds, so they can be used in alkaline or acidic regions. However, methods of dispersing alkyd resins using emulsifiers are known (for example, Japanese Patent No. 1j No. 54-166405, Futo No. 54-166406, etc.).
Products in which pigments are dispersed through cross-linking during coating are prone to agglomeration at high temperatures or long-term storage, and the use of emulsifiers reduces the water resistance, corrosion resistance, and drying properties of the paint film. was there.

In order to impart hydrolysis resistance to the ester bond, Mlh
m T , Tax%n f , I喀ml Hint
T--1ogy, To147% duty, 60λho rch1
975, 3D effect and antimetry effect (brocade, ahho
It has been proposed to use etriCm arm t) to make it less susceptible to hydrolysis attacks, but this has not been implemented to date.

Generally, as a method for improving the water dispersibility of 1-alkyd resins, polybasic acids such as 7-talic acid, inphthalic acid, terephthalic acid, tetrahydro-7-thalic acid, trimellitic acid, etc.
It has been attempted to attach a carboxyl group to the terminal end of the molecule, sometimes using acid anhydrides, but this method does not help improve hydrolysis resistance.

In order to overcome the above-mentioned drawbacks, the present inventors have conducted extensive research and found that polyurethane water has excellent hydrolysis resistance, agglomeration resistance, and mixing stability, as well as excellent coating film properties. He invented distributed fluency.

That is, the polyurethane dispersion of the present invention has an ethylene value of 1
00 or more oil and/or 100 parts by weight of the fatty acid 100 processed in a state where esterification and transesterification reactions are possible (hereinafter referred to as fatty acid oxyalkyl), and 1 to 100 parts of polyether polyol with a molecular weight of 1000 to 20000. 70 parts by weight and the general formula, R-C Tom-Coon 11 (wherein, R is C1C11Hj1+1 +, or C ridge 3
m+l- group, m is -CnH2n-1 or -CnH2h
-4-, the number of carbon atoms in one molecule is 10 to 20
．． ) is produced by reacting a polyinocyanate with a mixture of 5 to 80 parts by weight of an oxycarboxylic acid.

Contains ether bond and carboxyl group, molecular weight 150
It is characterized in that a polyurethane resin having a molecular weight of 0 to 50,000 is neutralized with amine and dispersed in water.

Within the technical scope of the present invention, oils with an iodine value of 100 or more mean drying oils and semi-drying oils, such as tung oil, soybean oil, linseed oil, dehydrated mustard oil, safflower oil, cottonseed oil, More than 111 selected from oil, tall oil, bran oil, etc. Among the fatty acids, in addition to fatty acids produced by hydrolyzing the above-mentioned oils, permolin (manufactured by Bar Φ Eles) 1 high diene acid, etc. It also includes synthetic fatty acids. Note that the weight of the fatty acid is a value converted to triglyceride.

Examples of the following Kdkfll alcohols are ethylene glycol, glupylene glycol, diethylene glycyl, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, glycerin, trimethy4-ethane, trimethylolpropane, Such as erythritol. As a matter of course, when producing fatty acid oxyalkyl from a fatty acid from an oil with an iodine value of 100 or more and a polyhydric alcohol, the amount of glycerin required for the fatty acid to become triglyceride is This calculated value is subtracted from the amount used, and this calculated value is calculated as the amount of polyhydric alcohol used within the technical scope of the present invention (i.e. 30
~500 parts by weight) K is used.

The reason why polyhydric alcohols are used is that, for example, in the case of oils, they are triglycerides, but by transesterifying the kernels with polyhydric alcohols, they are converted into fatty acid esters that have hydroxyl groups. This is to generate esters that have If the amount of polyhydric alcohol used is less than 30 parts by weight, the amount of urethane converted in the subsequent urethanization step will be small, resulting in a urethane resin with a small molecular weight, resulting in a coating film with poor drying properties and chemical resistance. of! ! However, if it exceeds 500 parts by weight.

In the subsequent urethanization step, the composition becomes non-uniform and the coating film tends to become cloudy.If the amount of 1-urethane is increased in order to avoid turbidity, gelation will occur during resin synthesis, making it impractical.

Next, polyether diols include polyether triols produced by the reaction of polyalkylene glycols such as polyethylene glycol and tetrapyrene glycol, glycerin, and trimethylolpropane with ethylene oxide and propylene oxide; Polyether polyol using 1,3-dioxane can also be used instead of the medium.

Polyether polyol has the property that the oxygen molecules in the ether bond are hydrated by hydrogen bonding, increasing its agglomeration resistance and miscibility stability, and gives a strong coating film, but fatty acid oxyalkyl If the amount is less than 1 part by weight per 100 parts by weight, almost no effect will be observed, and if it is used in excess of 70 parts by weight, the viscosity of the aqueous dispersion will become extremely high, and the solid content will be such that it cannot be used for practical purposes. Not only is it not possible to obtain a coating film, but it also forms a coating film with poor water resistance. Further, polyether polyols having a molecular weight of 1,000 to 20,000 can be used, and among them, those having a molecular weight of 2,000 to 8,000 give particularly good results.

Next, examples of the oxycarboxylic acids with the general formula % are 11-oxyhemosabcanic acid, ricinoleic acid, 2-oxydodeca/acid, oxycarboxylic acid, castor oil fatty acid, lanolin fatty acid, etc. 1 selected from synthetic dicarboxylic acids
It's more than a seed! Water-dispersed KFi has a large effect on water-dispersed KFi, but it is easy to obtain KFi with a carbon number of 16.1 B for industrial production, and as a result of experiments, the number of carbon atoms in one molecule is 10 to 10.
20 is desirable.

The action of these oxycarboxylic acids is that the hydroxyl group reacts with the incyanato group to produce a carboxy group-containing urethane resin. is a general term for alkylamines, alkanolamines, etc. substituted with various groups.) to form an anionic form,
This promotes dispersibility in water. The amount of this oxycarboxylic acid used is 5 parts by weight per 100 parts by weight of fatty acid oxyalkyl.
If the amount is less than 80 parts by weight, the water dispersibility of the resulting aqueous polyurethane dispersion will be poor, and if it exceeds 80 parts by weight, the agglomeration resistance and mixing stability will be good, but the viscosity will be extremely high, and the water resistance of the coating film will be poor. This is not practical because the properties deteriorate.

Next, examples of polyisocyanates used for urethanization include tolylene diisocyanate (!DI), pheasant diisocyanate, hydrogenated pheasylene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, naphthalene diinocyanate, etc. More than a species.

As will be illustrated in Examples below, a typical method for producing the aqueous polyurethane dispersion of the present invention involves first reacting a drying oil, a semi-drying oil, their fatty acids, etc. with a polyhydric alcohol to form a fatty acid oxyalkyl This product and the above polyether polyol are reacted with the above polyisocyanate in the presence of the above oxycarboxylic acid by a dropping method, a fractionation method, etc., and the carboxyl groups of the resulting polyurethane are reacted with an amine ( As mentioned above, it is neutralized with ammonia, alkylamine, alkanolamine, etc.) to form an aqueous dispersion.

Therefore, the amount of polyinocyanate used is preferably such that the molecular weight of the produced polyurethane resin is 1 soo to 5 ooooo. The amount added is determined to be 2000 to 30000K. At this time, the molecular weight of the polyurethane resin is 150
If it is less than 0, the drying property and water resistance of the coating film are poor, 5
If it exceeds 0,000, it becomes difficult to disperse in water and the flexibility of the coating film deteriorates.

Although not an essential component, aromatic-basic acids, such as
Benzoic acid, methylbenzoic acid, and tertiarybutylbenzoic acid can be used for molecular weight adjustment.

Next, embodiments of the present invention will be explained.

Example 1 A 490 flask was charged with 508.6 parts by weight of linseed oil, 3 parts by weight of trimethy p-ruguropa 7143f, and 0.2 parts by weight of stuchum naphthenate, and a transesterification reaction was carried out at 240°C for 2 hours. Cool and add mustard oil fatty acid (Yashiro Yushi Co., Ltd. 11 acid 1i 188.1, hydroxyl group $g
161. 53 parts by weight of polyethylene glycol (PKG400Q manufactured by Sanyo Kahi Kogyo Co., Ltd.) and 53 parts by weight of SO were mixed with stirring and then heated at a temperature of 60°C or less to prepare tolylene diisocyanate (TD Eny 0) 244 Immediately after the completion of 0 dropwise addition of 0.9 parts by weight over 1 hour, 2666.6 parts by weight of toluene was added and the reaction was carried out at 110°C for 4 hours. The obtained nine toluene/1III polyurethane resin had an acid 1i of 7.5, a Gardner-Holtz viscosity (25'°C) of z4+, and a nonvolatile content of 61% by weight. Moreover, the molecular weight was about 5,000.

Next, 166.6 parts by weight of the resin obtained in 1 was added with 4.4 parts of toluene.
parts by weight and 1.98 parts by weight of dimethylethanolamine were added, and after stirring, 122.2 parts by weight of water was added, and the mixture was dispersed for 5 minutes at 9000 rP and 1 m using a homo mixer. ℃)
An emulsion of 100 cp was obtained. Toluene was distilled off from this emulsion under negative pressure to reduce the solid content to a weight-viscosity of 45 (25°C).
) A polyurethane moisture mat with a pH of 9.9 and 2900 Cp% was obtained. This aqueous dispersion was left in a separate container for 30 days, but the viscosity remained unchanged and no aggregation or separation phenomena were observed.

Further, to 50 parts by weight of this aqueous dispersion, 56.25 parts by weight each of red iron oxide (red iron oxide) and water and 0.075 parts by weight of cobalt naphthenate (containing 6 metals) were added.
When dispersed for 4 hours with Sandogtinder, a paint with an Iu value of 50 was obtained without aggregates.Dry to the touch at F120℃ for 10 minutes, and after drying for 3 days, the edge hardness of the paint film was 11B, the coating film had excellent adhesion and impact resistance, had no fading in gloss, and had no blisters even when immersed in water for 24 hours.

Example 2 In the same reactor as in Example 1, 501.1 parts by weight of tall oil and 196.1 parts by weight of trimethylolepane were charged.
After reacting at 240°C until the acid value reaches 4.5, it is cooled and the castor oil fatty acid value is 52.6! Okibe and polypropylene glycol No. 10oo (manufactured by Sanyo Kakai Kogyo Co., Ltd.) 5
After adding 0 parts by weight to 1 part by weight and becoming uniform, add 200 parts by weight of tolylene diisocyanate (TDI-80) as in Example 1.
Add 2 parts by weight and 645.2 parts by weight of toluene and heat to 110°C.
The reaction continued until the viscosity became constant. The resulting polyurethane resin liquid had an acid value of 6.3 and a Gardner-Holtz viscosity (2 formula 9Y).
, non-volatile content was 60.5% by weight.

Add 33 parts by weight of toluene to 167 parts by weight of the obtained resin, further add 1.5 parts by weight of dimethylethanolamine to neutralize, add 122 parts by weight of water, and mix with a homomixer to 90% by weight.
00rP! Q for 5 minutes to obtain a milky white dispersion.

As in Example 1, a milky white dispersion containing toluene was mixed with 7
After dispersing with a 0-jet mixer, toluene was distilled off, and the solid content was 45% by weight and the viscosity (25'C) was 9006.
P%PI! An organic solvent-free polyurethane aqueous dispersion of No. 9.9 was obtained.

This dispersion was subjected to an accelerated stability test at 50° C. for 25 days and was found to have excellent stability with no pg change or viscosity change observed.

In addition, 50 parts by weight of red iron oxide was added to 50 parts by weight of this aqueous dispersion,
5 parts by weight of zinc white, 50 parts by weight of water, 6 parts by weight of butyl cellosolve, and 0.02 weight s of cobalt naphthenate as a metal were added to all of these, and the mixture was made into a paint using a sand grinder for 4 hours. As a result, a paint with a Kn viscosity of 65 was obtained that did not attract aggregates. Dry to the touch is 20
After drying for 3 days at ℃ for 15 minutes, the coating hardness was B, with excellent hardness and impact resistance, and the coating did not lose its luster or blister even when immersed in 24-gin seki water. Ta.

As mentioned above, the polyurethane aqueous dispersion of the present invention has excellent hydrolysis resistance, agglomeration resistance, and miscibility stability, and since it does not contain organic solvents, there is no risk of fire or air pollution, and it can be added as appropriate. If it is made into a paint by adding an agent, it will give an excellent IIXH.

Claims (1)

[Claims] Oil with an iodine value of 100 or more and/or its fatty acid Zo
o t It part and many 1j 7 v co-k 30~5
00500 parts by weight of the product treated in a state capable of transesterification and 100 parts by weight of the molecule t
0 to 20,000 polyether polyol and 1 to 70 parts by weight of the general formula % formula % (wherein R is CmH2m+I-1 or CmH2m-1
- group, mu is -cnH2n7 or -〇nH2n-
2-, and the number of carbon atoms in one molecule is 10 to 20. )
It is produced by reacting a polyisocyanate with a mixture of 5 to 80 parts by weight of an oxycarboxylic acid represented by the formula. 1 molecular weight including nityl bond and carboxyl group 1500~”
A polyurethane water drink characterized in that 5oooo polyurethane resin is neutralized with an amine and dispersed in water.