GB2190672A

GB2190672A - Surface coating compositions

Info

Publication number: GB2190672A
Application number: GB08612193A
Authority: GB
Inventors: Norman Walter Johnson
Original assignee: Coates Brothers and Co Ltd
Current assignee: Coates Brothers and Co Ltd
Priority date: 1986-05-20
Filing date: 1986-05-20
Publication date: 1987-11-25
Anticipated expiration: 2006-05-20
Also published as: EP0253474A3; GB8612193D0; EP0253474A2; GB2190672B

Abstract

A liquid composition, for use as a reactive solvent and/or diluent in a surface coating composition comprises one or more ether-esters of the formula: <IMAGE> in which R is a polyvalent hydrocarbyl group; R<1> is an ethylenically unsaturated hydrocarbyl group containing from 18 to 24 carbon atoms; and a, b and c are each integers such that the total of a, b and c is from 3 to 6, a and b are each at least 1 and the total of a and b is at least 3. The compositions are used as reactive solvents/diluents in surface coating compositions typically also comprising a film-forming material and a volatile organic solvent.

Description

1 GB 2 190 672 A 1

SPECIFICATION

Surface coating compositions 5 This invention is concerned with improvements in and relating to air- drying su rface coating compositions for use in the formulation of decorative paints and varnishes. More particularly, the invention is concerned with reactive solvents and/or diluents for use in surface coating compositions and to coating compositions con taining such solvents a ndlor dil uents.

Liquid surface coating compositions comprising a fil m-forming material, generally a resinous material, 10 dissolved in an organic solvent are, of cou rse, very well known. The solvents which have been most com mon ly used are volatile organic solvents so that after a coating composition containing them is appi ied to a substrate, solvent evaporates to leave a f il m of coating material which then cu res or dries on the substrate.

Volatile organic solvents often present environmental problems. Thus, one commonly employed solvent, white spirit, is regarded as potentiously hazardous in view of its relatively high content of aromatic hydrocarbons.

In orderto overcome the possible problems associated with such potentially hazardous solvents it has been proposed (a) to replace such solvents by other less toxic solvents, such as the isoparaffin ic solvents; or (b) to reduce the overall amount of solvent employed. Proposal (a) suffers from the disadvantage thatthe proposed replacement solvents are general ly weaker solvents than, say, white spirit so that for the same 20 application viscosity the corn position will have a reduced so] ids content which wil 1 result i n a loss in build and performance. In order to maintain build, lower viscosity resins have to be formulated and evaluated and this can be time-consuming and costly and in many cases is fou nd that final performance is u nsatisfactory.

Proposal (b), reduction of overal 1 solvent content, results in a product having an increased viscosity and, hence, unacceptable application properties. Again reformu iation and eva luation are requi red with the pos- 25 sibility of unsatisfactory f inal performance.

One way in which lower toxicity solvents or lower levels of possibly toxic solvents may be em ployed with known fil m-forming resins, without adversely affecting solids content or application properties, is to incor porate a reactive diluent in the corn position. Such a reactive diluent does not evaporate off f rom the composi tion, when it has been applied to a su bstrate, but remains to form part of the fil m-formi ng corn position. 30 Exam pies of reactive diluents which have been proposed for this use are allyl ethers of polyols such as glycerol, trimethylol propa ne and pentaerythritol. The use of such materials. however, presents additional problems associated with odour or performance (i.e. giving rise to poor dry, poor g loss retention and embrittlement).

It has now been fou nd, in accordance with the present invention, that certain esters of polyhydric alcohols 35 which have been partial ly etherif ied with al lyl alcohol are usefu 1 reactive diluents in that they are generally of low viscosity, are good solvents, a re virtual ly odou r-free and do not ma rkedly affect dry or performance of the final composition.

According to the invention, therefore, there is provided a liquid composition, for use as a reactive solvent andlor diluent in a surface coating composition, comprising one or more ether-esters of theformula: 40 (Offic 1 - (Rl-t;uu---a h---OCH2- CH = CHA 45 in which R is a polyvalent hydrocarbyl group, preferably a polyvalent aliphatic carbyl group; R' is an ethylenically unsaturated hydrocarbyl group containing from 18to 24 carbon atoms; and a, b and c are each integers such thatthetotal of a, b and c isfrom 3to 6, a and b are each at least 1 andthe 50 total of a and b is at least3.

The ether-esters of the invention may conveniently be prepared by esterifying an appropriate ally] etherof a polyhydric alcohol containing free hydroxyl groups with an appropriate unsaturated acid, or mixture of unsaturated acids, at a temperature of from 200to 2401C, in the presence or absence of a solvent, the reaction being carried out until a low acid value is obtained. 55 Suitable polyhydroxy compounds include glycerol, trimethyl propane, pentaerythritol and sorbitol.

Suitablefatty acids include unsaturated aliphatic acids such as oleic, linoleic and linolenic acids. Aswill be appreciated, compositions in accordance with the invention will most conveniently be prepared from com mercially available mixtures of appropriate unsaturated acids (such astall oil fatty acids and the mixtures of fatty acids derived from soya bean oil and linseed oil). Accordingly, compositions in accordance with the 60 2 GB 2 190 672 A 2 inventionwill commonly comprise mixtures of estersof various acids and may alsocontain small pro portions of esters of saturated or aromatic carboxylic acids.

The invention furtherprovides a surface coating composition comprising afilm-forming material (such as an alkyd ormodified alkyd resin, a urethane oil oran epoxyester resin), avolatile organic solvent and a reactive solvent and/or diluent composition as defined above. Such coating compositions suitably contain 5 from 5to 30% byweight, preferablyfrom 5to 15% byweightof the reactive diluent.

In orderthatthe invention may bewell understood the following Examples are given bywayof illustration only. Inthe Examples all parts and percentages are byweightunless otherwise stated.

jo Example 1 10 A reactive diluent containing approximately one fatty acid residueandtwo allyl groups permoleculewas prepared as follows. Trimethylol propanediallyl ether(45.6 parts),tall oilfattyacids (54.4parts) anddibutyl tin oxide(O.03 parts) were charged to a reaction vessel fitted with astirrer, nitrogen inlet and side arm to allow fordistillation ofwaterto a receiver. The temperature was raised to 2WC and heldfor7 hours. Oncoolingthe diluenthad aviscosityof 0.23 poiseand an acidvalueof 7.OmgKOH/9. 15 Examp/62 A reactive diluent containing approximately two fatty acid residuesand oneallyl group permoleculewas prepared in a similar manner to that described in Example 1 fromtrimethylol propane monoallyl ether(24 parts),tall oilfattyacids (76parts) and dibutyltin oxide (0.03 parts).The producthad aviscosityof 0.47poise 20 and an acid value of 12 mgKOH1g.

Example 3 (Comparative) A reactive diluent containing approximately one fatty acid residue and one allyl group per moleculewas prepared following the procedure of Example 1 from trimethylol propane mono ally] ether (38.7 parts) tall oil 25 fatty acids (61.3 parts) and dibutyl tin oxide (0.03 parts). The product had a viscosity of 0.47 poise and an acid value of 12 mgKOH1g.

Example 3 (Comparative) A reactive diluent containing approximately one fatty acid residue and one allyl group per molecule was proposed following the procedure of Example 1 from trimethylol propane mono allyl ether (38.7 parts) tall oil fatty acids (61.3 parts) and dibutyl tin oxide (0.03 parts). The product had a viscosity of 0.59 poise and an acid value of 8.4 mgKOH1g.

Example 4 (Comparative) 35 A reactive diluent containing approximately one fatty acid residue and one ally] group per molecule was prepared from ally[ glycidyl ether (28.9 parts) and tall oil fatty acids (71 parts) by reaction at 16WC in the presence of an epoxy acid catalyst. The product had a viscosity of 0.55 poise and an acid value of 12.2 mgKOH19.

The products of Examples 1-4were tested as follows. 40 Test 1 This test illustrates howthe reactive diluents may be used to maintain the solids content and viscosity of a commercially available type of alkyd composition (Syn 60W made by Cray Valley Products Limited), when the normal solvent (white spirit) is replaced by a less toxic but weaker solvent (Shel 1sol TD). Only products 45 containing two ally] ether g roups or two fatty acid g roups/mole gave acceptable dry.

Thus, compositions were made up comprising the alkyd resin (Syn 60W), solvent (Shellsol TD), diluent, and a drier solution comprising cobalt, zirconium and calcium to give a composition having a viscosity of 2 poise. (The solids content of the composition at this viscosity was noted). The composition were then applied to substrates and evaluated. By way of comparison, similar compositions were made comprising white spirit 50 as solvent, Shellsol TD only as solvent and Shel lsol together with trimethylol propane dial ly] ether as diluent.

The results are shown in Table 1.

In Table 1, the results underthe heading "BX dry" refers to results obtained bythe Beck Koller drytest; the figures under (a) indicating the time taken for solvent loss, those under (b) the time at which the coating was touch dry,those under (c) the time at which the coating was hard dry and those under (d) the time atwhich 55 the coating film was fully oxidised.

Table 1

Solvent Diluent % Solidscontent B.K.Dryat20'C(Hrs) Drying 60 2 poise (a), (b), (c) (d) R129 - 53 12 7 >24 Satisfactory ShellsolTD - 47 113/4 6 >24 Satisfactory 65 3 GB 2 190 672 A 3 Shellsol TD Exl 10 53.2 11/4 2 10 >24 Satisfactory ShellsolTD W 13 53.4 11/4 21/4 12 > 24 Satisfactory ShellsolTD W 12 53.1 11/4 41/2 > 24 B]. tacky film OX Shellsol TD Ex4 12 53.5 2 5 >24 tackyfilm OX ShellsolTD T.M.P.D.E. 9 53.3 11/4 2 81/2 >24 Satisfactorydry 5 Unacceptable odour Test2 Thistest demonstates howthe reactive diluents can be used with an alkyd thinned in white spiritto give higher solids system of reduced solvent toxicity. The same alkyd as used in Test 1 was employed. 10 The results of the tests, which were carried out in a similar mannerto Test 1, are shown in Table 2.

Table2

Diluent % Initial Viscosity (p) Solidsat2p 13K Recorder at 200C HRS (a) (b) (c) (d) 15 Exl 10 13.8 59 11/4 2 12 >24 Exl 20 17.1 67 11/2 3 18 >24 Ex2 10 8.3 58.3 11/2 3 12 >24 Ex2 20 9.8 65.5 11/2 3 20 >24 20 - 30.1 53 1 13/4 8 >24

Claims

25 1. A liquid composition, for use as a reactive solvent and/or diluent in a surface coating composition, comprising one or more ether-esters of the formula:

(OH)c 1 30 (R,-uuu---a K-(-OCI-12 - CH = CH2)b in which R is a polyvalent hydrocarbyl group; R' is an ethylenically unsaturated hydrocarbyl group containing from 18to 24carbon atoms; and a, b and c are each integers such thatthe total of a, b and c is from 3 to 6, a and b are each at least 1 andthe 35 total a and b is at least3.
2. A composition as claimed in claim 1 in which R is a polyvalent aliphatic group.
3. A composition as claimed in claim 1 substantially as hereinbefore described with reference to the Examples.
4. A surface coating composition comprising a film-forming material, a volatile organic solvent and a 40 reactive solvent and/or diluent composition'as claimed in anyone of claims 1 -3.
5. A surface coating composition as claimed in claim 4 containing from 5 to 30% by weight of reactive diluent composition.
6. A surface coating composition as claimed in claim 4 substantially as hereinbefore described with refer- enceto the Examples. 45 Printed for Her Majesty's Stationery Office by Croydon Printing Company (UK) Ltd, 10187, D8991685. Published by The Patent Office, 25 Southampton Buildings, London WC2A 'I AY, from which copies maybe obtained.