WO1994018260A1

WO1994018260A1 - Water-soluble and air-drying resin

Info

Publication number: WO1994018260A1
Application number: PCT/NL1994/000019
Authority: WO
Inventors: Gerrit Hendrik Dekker; Johannes Wilhelmus Maria Hendriks; Dick Adriaan Pons
Original assignee: Dsm N.V.
Priority date: 1993-02-09
Filing date: 1994-01-27
Publication date: 1994-08-18
Also published as: FI953763A; EP0683802A1; NO953086L; BE1007442A3; AU5892594A; FI953763A0; NO953086D0

Abstract

The present invention relates to a water-soluble and air-drying resin. A water-soluble and air drying resin, comprising substantially units of: A. a monoether of a polyethylene glycol having 5-100 ethylene oxide units per molecule, and B. the reaction product of: B1) one or more usaturated fatty acids or one or more polyalcohol(s) esterified with unsaturated fatty acids with B2) an α,β-ethylenically unsaturated carboxyl compound wherein the molar ratio of A:B is from about 0.2:1 to about 4:1. The resin can amongst others be used as a dispersing agent, in a wood preservative and in a pigment paste.

Description

WATER-SOLUBLE AND AIR-DRYING RESIN

The present invention relates to water-soluble, air-drying resins and a process for making the same. The present invention further relates to the use of said resins as dispersing agents and as agents for use in wood preservation applications.

Examples of water-soluble resins that can be used as dispersants are described in Paint Flow and Pigment Dispersion, by T.C. Patton (pp. 290-296, 1979). Known dispersants such as for example polyphosphates, isobutylene maleic acid copolymer-sodium salt and polyacrylates cannot b sufficiently mixed with binders like alkyd resin dispersions in order to obtain paints with good gloss properties. It is also possible to use water-dilutable alkyd resins as dispersants for pigments. In order to obtain clear solutions and good properties (i.e. for instance pigment wetting properties), however, the known resins used as dispersants have to be combined with compounds that are undesirable for environmental and medical reasons, such as, for example, amines or organic solvents.

Water-soluble resins which can be used as dispersants are also known from W091/06586. This publication describes a resin which is substantially built up from units of:

A. a polyethylene glycol with ethylene oxide units,

B. an allyl ether compound and

C. the reaction product of an oil and an unsaturated compound The drawback of these resins is the release of acrolein upon oxidative drying, because acrolein is injuriou to health. The water-soluble and air-drying resin according the present invention is characterized in that the resin comprises substantially units of:

A. a monoether of a polyethylene glycol having 5-100 ethylene oxide units per molecule, and

B. the reaction product of

Bl) one or more unsaturated fatty acids or one or more polyalcohol(s) esterified with unsaturated fatty acids with B2) an α,β-ethylenically unsaturated carboxyl compound wherein the molar ratio of A:B being from about 0.2:1 to about 4:1.

Given the drawbacks associated with prior water- soluble resins, the present invention provides properly processable, air-drying and water-soluble resins which are suitable as dispersants. These resins result in coatings having desired properties such as for example a good gloss. further important advantage of the resins according to the present invention is that they do not release acrolein whil drying.

The preferred molar ratio of A:B is about 1:1. The reaction product of one or more unsaturated fatty acids or one or more polyalcohol(s) esterified with unsaturated fatty acids is generally indicated as an oil. The monoether of polyethylene glycol is for examp an alkyl ether, an aryl ether or an alkylaryl ether. Preferably the ether is an alkyl ether. Monoethers of polyethylene glycol have at one side a hydroxyl group remaining, which can react with the carbonyl compound. In general, the alkyl group in the alkyl ether ha between 1 and 18 carbon atoms, and preferably between 1 and carbon atoms. The alkyl ether of polyethylene glycol can be for example, methoxy, propoxy or butoxy polyethylene glycol Other suitable alkyl groups include, for example, an octyl- lauryl- (C₁₂) and a cethyl- (C₁₆) group.

Preferably, component A is a methoxy polyethylene glycol having 8 to 20 ethylene oxide units per molecule. The polyethylene glycol (PEG) can be used in a fo in which one or more fragments of polypropylene glycol (PPG) are linked to the PEG. Such a molecule is called a block polymer. The PPG/PEG ratio can be set as desired, taking in account the water solubility of the resin. Generally, 70-95 of the block copolymer will be PEG, and preferably 80-90%. the alkyl group is a methyl group, this results in a methox polypropylene glycol/polyethylene glycol block polymer a methoxy polyethylene glycol/polypropylene glycol block copolymer. Preferably the polyethylene glycol has 8-20 alkoxide units per molecule. More preferably, the polyethylene glycol has 10-16 alkoxide units per molecule. The number of alkoxide units per molecule is chosen so that the resin is water soluble. Suitable unsaturated fatty acids esterified with polyalcohols include, for example, linseed oil, soybean oil, safflower oil, oiticica oil, caraway oil, rapeseed oil, woo oil and fish oil. It is also possible to use diesters and triesters of polyalcohols, such as glycerol, trimethylol propane or pentaerythritol. And as unsaturated fatty acids, tall oil fatty acid and the fatty acids of the above- mentioned unsaturated oils can be used.

Preferably, the α,β-ethylenically unsaturated carboxyl compound is a carboxyl compound, such as, for example, (meth)acrylic acid or cinnamonic acid. More preferably, the compound is a dicarboxylic compound such as for example maleic acid, fumaric acid, itaconic acid, citraconic acid and mesaconic acid. Most preferably, the α, ethylenically unsaturated carboxyl compound is an anhydride, such as for example maleic anhydride, itaconic acid anhydri or citraconic anhydride.

Preferably the α,β-ethylenically unsaturated carboxyl compound is a maleic anhydride.

According to a preferred embodiment of the present invention, component B is the reaction product of linseed oi and/or safflower oil with maleic anhydride.

Thus, a low-viscosity, easily processable, air- drying and water-soluble resin is obtained. If used as a paint dispersant, this resin results in a paint with desirable properties such as for example a good gloss and a good water resistance. The resin results also in good pigme wetting properties with respect to organic and inorganic pigments.

Moreover, this resin need not be combined with compounds such as for example amines or organic solvents. In other words, a solvent-free system is obtained. Another advantage of the use of the resin as dispersant is the minimis foaming of the dispersant during the preparation of the paint. Consequently little or no ant foaming agents are required.

The resin according to the present invention is very suitable for use as a dispersant if it has the followi characteristics:

(1) a number-average molecular weight M_n of between 1000 an 4000;

(2) a weight-average molecular weight M_w of between 2000 a 8000.;

(3) a polydispersity y/M-, of between 1.5 and 3.5;

(4) a viscosity higher than 3 dPa.s at 23°C. More preferably, the viscosity is higher than 5 dPa.s. The resin can also be solid or waxy, depending upon the molecular weight. When there are 16 or more ethylene oxide units, the resin will be more or less waxy; and

(5) a iodine value of between 50 and 150 g iodine/100 g resin.

The molecular weights have been determined by mea of GPC (Ultrastyragel, Waters, 100A, 1000A, 10,000A separating capacity M_w 200-300,000).

The viscosity has been determined at 23°C using a rotational viscosimeter (DIN 53019, Bohlin).

The iodine value has been determined by means of ASTM D 1959-85.

Since the polydispersity of the resin is between 1.5 and 3.5, hardly any preferential adsorption of high- molecular weight product takes place.

The present invention also relates to a process f preparing the resins described above as being substantially made up of components A and B. According to a preferred embodiment of the invention, in a first reaction step, component B is prepare by means of an addition reaction of an α,β-ethylenically unsaturated carbonyl compound, preferably maleic anhydride, with an unsaturated vegetable oil (i.e., linseed oil or safflower oil), at a temperature above about 150°C. These t components provide the best results when present in an approximately equimolar quantity. In a second step, compoun A is added, and the esterification reaction is carried out. Generally, the molar ratio of A:B is from about 4:1 to about 1:4 and is preferably about 1:1.

The resins according to the present invention als include modified resins which are based on the present resi

The acid groups of the resin can, for example, be modified by neutralizing the remaining acid groups with, for instance, hydroxides, oxides, acetates or salts of metals from Groups IA, IIA, IIB of the Periodic Table. Metals from these groups include, among others, Li, Co, V, Zr, Na, K, C Mg and Zn. This process can be performed at room temperatur This modification can also take place by esterifying the acid groups with a compound chosen from the groups consisting of alkoxy polyethylene glycols, monofunctional C₂-C₁₆ epoxy compounds, glycidyl (meth)acrylate, hydroxyalkyl sulphonic acids, aminoalkyl sulphonic acids, hydroxyalkyl phosphonic acids or aminoalkyl phosphonic acids at a suitable temperature, for instance 15 180°C.

Glycidyl (meth)acrylate should preferably be used at a temperature lower than 150°C so as to prevent the acrylate group from reacting. A catalyst can optionally be used with the glycidyl (meth)acrylate. Suitable catalysts include, for example, triethylamine and N,N-dimethylanaline. Suitable examples of hydroxyalkyl sulphonic acids include f example 2-hydroxyethyl sulphonic acid, p-hydroxybenzene sulphonic acid or aminoalkyl sulphonic acids, such as 1- aminobutane sulphonic acid-4 and p-aminobenzene sulphonic acid. Also, propylene oxide or butylene oxide can be us as modifying agent.

It is also possible to neutralize the acid group with ΝH₄OH or an amine. Although such neutralization is within the scope of the present invention, it can have the disadvantage of creating undesirable environmental effects. The molar ratio of the reactants in the modification reaction is substantially 1:1.

The resin according to the present invention can used, for example, as a dispersant, a grinding agent and a wetting agent for pigments in combination with alkyd resins epoxy ester resins and polymer emulsions.

A suitable pigment pasta contains, for instance, 50-70% wt.% pigment, 3-7% wt.% resin according to the prese invention and 20-45% wt.% water. The use of the resin according to the present invention as an air-drying, water-soluble dispersant result in a substantially improved solubility and compatibility with, for instance, alkyd emulsions. In this way, systems with a good gloss are obtained. The resin according to the present invention can also be used as a water-soluble and air-drying binder.

Another possibility of the resin is the use in a water-soluble wood preservative as a vehicle. When used in wood preservative, it is used instead of so-called Wolman salts against rotting. A side effect is that the resin according to the invention has a water repellent effect. Th will enhance the dimensional stability of wood (as measured by its water uptake).

The resin according to the present invention can also be used as an air-drying plasticizer in, for instance, acrylate dispersions. Traditional coalescing agents for acrylate dispersions include, for instance, (ethers of) ethylene and propylene glycols. These compounds, however, evaporate during the drying of a film, which is undesirable for the environment. The resin according to the present invention does not possess this disadvantage. Another use of the resin according to the present invention is as a drying emulsifier for the preparation of alkyd emulsions and in acrylate dispersions.

The resin according to the present invention can b mixed with the customary additives for obtaining paint compositions. Suitable additives include, for example, pigments, colorants, fillers, thickeners, flow-promoting agents, thixotropic agents, flatting agents, stabilizers and siccatives.

The present invention is elucidated by means of th following non-restrictive examples.

Example I

Preparation of a resin

In a four-necked flask provided with a nitrogen feed system, mechanical stirrer, thermocouple and dropping funnel, 98 parts by weight maleic anhydride was added at 215°C to 878 parts by weight linseed oil and stirred at 215° until no reflux of maleic anhydride was visible any more. T resulting product (component B) was an oil-like, low- viscosity liquid with a total acid number of 115 mg KOH/g sample.

Subseguently, 750 parts by weight methoxy polyethylene glycol having 16 ethylene oxide units per molecule (component A) was added to this product. Next, the mixture was kept at the same temperature for several hours. After cooling, a water-soluble waxy product having the following properties was obtained:

* solids content: 100%

* iodine value: 110 g I₂/100 g product * acid number: 35 mg KOH/g product

* viscosity (23°C): waxy Example II and Comparative Experiment A Preparation of a Paint

In a Cowless dissolver, a pigment paste based on dispersant, titanium dioxide, thickener and demineralized water was prepared in 30 minutes at 3000 rpm, according to Table I below.

TABLE I

A π

Resin according to Example I — 0.60

Orotan 731^R, 25% ^1} 0.65 0.65

Demineralized water 9.30 14.80

Borchigen DFN^R/demineralized water 5.00 — 1:2 ²⁾

Kronos 2190^{R 3)} 30.02 30.20

Agitan 295^{R )} 0.10 0.10

Dispersion in pearl mill Premix:

Uradil XP 516 AZ^{R 5)} 49.40 49.40

Acrysol RM 8^{R 6)} 0.75 0.50

Siccatol 938^{R 7)} 1.50 1.50

Urad DD 8l^{R 8>} 0.25 0.25

Adding pigment paste to premix

Addition of:

Acrysol RM 8^R 1.20 0.35

Acrysol RM 1020^{R 9}> 0.60 0.60 Fluorad FC 129^R/ ater (10%) ^10> 1.05 1.05

Pigment-volume concentration, % 20 19.6

Solids content, % 60.7 61.3

Viscosity 23°C (DIN 53019), dPa.s 30 20

PH 7.00 7.30 A II

BK drying time, stage 1, min ¹¹⁾ 20 40 BK drying time, stage 2, min ^{l )} 150 100 BK drying time, stage 3, min ¹¹⁾ 650 220 BK drying time, stage 4, min ^11> 1100 950 Gloss 20° 83 95 Gloss 60° 95 90

Hardness(s), 1 day 27 28 Hardness(s), 1 week 38 40 Adhesion to wood ¹²⁾ 3 3 Adhesion to alkyd ¹²⁾ 5 5 Water resistance, after 1 week ¹²⁾ 4 4 Adhesion wood, after 1 week ¹²⁾ 5 5 Adhesion alkyd, after 1 week ¹²⁾ 5 5

1) Orotan 73^R: dispersant, isobutylene maleic acid copolymer, Na salt

2) Borchigen DFN^R: pigment wetting agent

3) Kronos 2190^R: titanium dioxide

4) Agitan 295^R: anti-foaming agent

5) Uradil XP516A2^R: alkyd emulsion of DSM Resins

6) Acrysol RM8^R: polyurethane thickener

7) Siccatol 938^R: siccative mixture

8) Urad DD81^R: anti-skinning agent

9) Acrysol RM1020^R: polyurethane thickener

10) Fluorad FC129^R: flow-promoting agent

11) The drying time was determined by means of a BK drying recorder (BYK-Chemie no. 270, Mickle Laboratory

Engineering Co., Gomshall, Surrey, England) 6) Visual assessment with the following rating:

1 = unacceptable

2 = insufficient

3 = sufficient

4 = good

5 = excellent

Table I demonstrates that the gloss is improved considerably if instead of Borchigen DFN^R, the resin according to the present invention is used. Moreover, the other desired properties are preserved when the resin according to the present invention is employed.

Claims

WHAT IS CLAIMED IS:

1. A water-soluble and air drying resin, comprising substantially units of

B. the reaction product of:

Bl) one or more unsaturated fatty acids or one or more polyalcohol(s) esterified with unsaturated fatty acids with B2) an α,β-ethylenically unsaturated carboxyl compound wherein the molar ratio of A:B is from about 0.2:1 to about 4:1.

2. A resin according to claim 1, wherein said monoether is an alkyl-, aryl- or alkylaryl ether.

3. A resin according to any one of claims 1-2, wherein the monoether contains 8-20 ethylene oxide units per molecule.

4. A resin according to any one of claims 1-3, wherein B i the reaction product of linseed oil and/or safflower oi with maleic anhydride.

5. A process for preparing a water-soluble and air-drying resin according to any one of claims 1-4, comprising t steps of:

(1) preparing component B by means of an addition reaction of an α,β-ethylenically unsaturated carboxyl compound with an unsaturated vegetable oi at a temperature above 150°C, and (2) reacting component B with a component A comprisin a monoether of a polyethylene glycol having 5-100 ethylene oxide units per molecule, such that the molar ratio of A:B is from about 4:1 to about 1:4.

6. A process according to claim 5 wherein in the first ste the α,β-ethylenically unsaturated carboxyl compound and the unsaturated vegetable oil are present in an approximately equimolar quantity.

7. Use of a resin according to any one of claims 1-4 or us of a resin obtained according to any one of claims 5-6.

8. Use of a resin according to any one of claims 1-4 or us of a resin obtained according to any one of claims 5-6 as dispersing agent.

9. Use of a resin according to any one of claims 1-4 or us of a resin obtained according to any one of claims 5-6 as a vehicle in a wood preservative.

10. Pigment paste comprising a resin according to any one o claims 1-4 or comprising a resin obtained according to any one of claims 5-6.