WO2005040241A1

WO2005040241A1 - Fast drying coating composition comprising an unsaturated hydroxydiester

Info

Publication number: WO2005040241A1
Application number: PCT/EP2004/011334
Authority: WO
Inventors: Annie Bernadette Michèle Ghyslaine FONZE; Denis Marie Charles Heymans; Griet Uytterhoeven
Original assignee: Hexion Specialty Chemicals Research Belgium S.A.
Priority date: 2003-10-15
Filing date: 2004-10-11
Publication date: 2005-05-06
Also published as: TW200526747A; EP1524280A1

Abstract

A resin composition specially adapted for use as a top coat on metal substrate with a fast drying speed. The thermosetting resins are prepared from a radical copolymerisation of an unsaturated hydroxyalkyl diester and acrylic or methacrylic and vinyl monomers, the resins are curable with a curative which react with the hydroxyl functionality. More particularly this invention relates composition of a resin prepared by radical polymerisation of alkyl, hydroxyalkyl diester maleate monomers.

Description

FAST DRYING COATING COMPOSITION COMPRISING AN UNSATURATED HYDROXYDIESTER The present invention relates to a resin composition specially adapted for use as a fast drying top coat on a metal substrate. The thermosetting resins of this invention are prepared from a radical copolymerisation of an 5 unsaturated hydroxyalkyldiester and acrylic and methacrylic and vinyl monomers. The resins are curable with a curative which react with the hydroxyl functionality. More particularly this invention relates to a composition of a resin prepared by radical polymerisation of alkyl, -0 hydroxyalkyl diester maleate monomers.

Fast drying coating compositions which may meet the presently required properties of the modern automotive painting industry have been proposed over the past decade . The fast

L5 drying behaviour of a paint in the automotive area is a major factor in the productivity of this industry. It is known that increasing the T_g of the resin by selecting the monomer type (such as methacrylate derivatives) helps to shorten the drying time as known from e.g. US 5,279,862 and US 5,314,953.

10 However the increased drying speed is accompanied by an unacceptable deterioration of the appearance of the coating. The US 5,514,755 relates to a composition comprising units derived from isobornyl methacrylate and 4-hydroxybutyl acrylate . In order to reach high hardness of the cured film,

15 a high concentration of isobornyl methacrylate has to be incorporated in the resin composition, which lead to negative economical balance. The US 5,741,880 discloses that a clear coat based on 20-55% by weight of isobornyl methacrylate and 20-55% by weight of hydroxypropyl methacrylate leads to a

50 fast drying coating composition when cured with a combination of polyisocyanates . Moreover said US-, 5 , 741, 880 disclosed that high solids content compositions could be reached by lowering the molecular weight of polymers, which implied the addition of specific polymerisation chain regulators. US 6,130,286 of specific polymerisation chain regulators. US 6,130,286 claims that the reaction product of a hydroxyalkyl (meth) acrylate and ε-caprolactone and isobornyl methacrylate or the like are suitable to achieve the excellent physical properties and appearance and meet simultaneously the increasing stringent requirements for lower volatile content. A recent US patent (US 6,458,885) disclosed a fast drying coating composition based on an acrylic polyol and a specific polyisocyanate curing agent composition.

From said cited publications it can be derived that the prior art solutions suffer from disadvantages such as combination of expensive acrylate monomers, or deterioration of the other required properties for automotive paint applications. Therefore an object of the present invention was a new coating composition that could fulfil the future VOC legal European regulations (VOC lower than 420 g/1) and in addition show a fast drying behaviour. The drying (or "dry to handle") of a coating composition is measured for example by the combination of dust free time and tack free time.

As result of extensive research and experimentation, it has now surprisingly been found that incorporation of alkyl , hydroxyalkyl diester maleate monomers by radical polymerisation with other unsaturated monomers leads to curable coating composition that meet the current automotive requirements and has a short drying time and a VOC lower than or close to the future legal level .

A composition for coating application based on hydroxyalkyl unsaturated ester was already described in US-3,414,635 or GB-1,168,078 on said document the authors concluded in col 4, lines 51-53 (of US- ,635) that the hydroxylaklyl alkyl maleate diesters are more difficult to polymerise with acrylic monomers . Surprisingly , it has been found now that a hydroxyl functional resin can be produced starting from the reaction product of an unsaturated l-2,diacid or anhydride or a mixture thereof and a secondary alcohol and the subsequent reaction of the intermediate monoester of the unsaturated diacid (or anhydride) with an mono-epoxy compound and optionally in the presence of a catalyst known in the art for acid-epoxy reaction. The unsaturated asymmetric hydroxyl functional diester is further used as co-monomer to produce the said hydroxyl functional resins with a high degree of conversion of the above diester.

The preferred unsaturated diacids or anhydrides are maleic acid or anhydride or citraconic acid or anhydride or a mixture of maleic and citraconic acid or anhydride. The most preferred is maleic anhydride.

The half ester of the diacid or anhydride are preferably derived from secondary alcohol with alkyl chain (linear, branched, cyclic) with 3 to 20 carbon atoms and preferably with 3 to 16 carbon atoms. Particulary suitable alcohols are: iso-propanol, sec-butanol, methyl isobutyl carbinol, di-isobutyl carbinol, tridecyl/isodecyl alcohol, isobornyl alcohol, cyclohexanol , 3,3,5 trimethyl cyclohexanol , tetrahydrofurfuryl alcohol , or a mixture thereof.

Any suitable monoepoxy compound can be used in the reaction with the half ester derived from the condensation of the anhydride or acid and any of the above cited alcohols . Any alkyl or aryl monoglycidyl ethers or alkyl glycidyl esters can be reacted with the acid group of the half ester. Preferably alkyl glycidyl esters are used, which correspond to the general formula (I) ,

in which R,R',R" are independently hydrogen or aliphatic alkyl radicals off 1 to 10 carbon atoms, while the total number of carbon atoms of the three radicals (R+R' +R" ) being between 1 to 20, preferably between 3 to 13. These alkyl glycidyl esters are derived for example from 1- methylpropionic acid, 1-dimethyl -propionic acid (pivalic acid) , iso-butyric acid, 1-methyl -propionic acid, 1-methyl - butyric acid, 1-dimethyl-butyric acid, VERSATIC acid, neodecanoic glycidyl ester and other glycidyl ester of alkanoic acids and mixture thereof and the like. The most preferred glycigyl ester is CARDURA E10P glycidyl ester, which derived from VERSATIC 10 carboxylic acid (CARDURA & VERSATIC are trademarks from Resolution Performance Products) . The said glycidyl esters are obtainable by a well established manufacturing process such as disclosed in EP-1 115 714 Bl.

Optionally a catalyst well known in the art for the acid- epoxy reaction can be used.

The resulting unsaturated hydroxyl functional asymmetric diester, can be used without any additional purification step, before the copolymerisation as monomer according to the following process. We have found that if 70 to 100 weight percent of the unsaturated hydroxyl functional asymmetric diester is charged in the reactor and that the other co- monomers (added as a mixture or as independent feed) are subsequently added then high conversion rate of the said diester is achieved.

The co-monomer may be chosen from aromatic vinyl monomers, preferably styrene also, including substituted styrene such as alpha- substituted vinyl aromatic compounds including vinyl toluene, alpha-methylstyrene and the like. Beta substituted styrene compounds can also be used, such as stylbene, beta- methylstylbene, and the like. Another class of suitable vinyl monomers are alpha-olefins with a carbon chain length of more than 10 and preferably those with 10 to 25 carbon atoms. Vinyl ethers which contain alkyl, aryl or cycloaliphatic groups with a. carbon chain length 5 to 15 and preferably from 5 to 10. Vinyl esters such as vinyl acetate, benzoate and Versatate 5 (e.g. VEOVA 10 or VEOVA 9 vinyl esters (VEOVA is a trademark ex RPP) and the like are suitable co-monomers to be used in the process of this invention.

Alkyl acrylate and/or an alkyl methacrylate, contains an .0 alkyl group having from 1 to 12 carbon atoms, and preferably from 1 to 10 carbon atoms. Particularly suitable monomers of the group are selected from methyl-, ethyl-, propyl-, iso— propyl , n-butyl, iso-butyl, isobornyl esters of acrylic acid or methacrylic acid. L5 More preferred are methyl acrylate or methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate or n- butyl methacr/ylate . Other suitable monomers are selected from hydroxy ethyl acrylate, hydroxy ethyl methacrylate, hydroxy n-propyl

20 acrylate, hydroxy n-propyl methacrylate, hydroxy isopropyl acrylate, hydroxy isopropyl methacrylate, hydroxy n-butyl acrylate, hydroxy n-butyl methacrylate, hydroxy isobutyl acrylate or hrydroxy isobutyl methacrylate. Other alkyl deficient monomers, such as symmetric 15 unsaturated diesters e.g. alkyl maleate, alkyl fumarate, and the like could be part of the co-monomer mixture.

Suitable polymerization initiators to be used for free radical copolymerization include any of the conventional

30 free radical forming compounds, individually or in a mixture . Examples of such compounds are aliphatic azo compounds, diacyl peroxides, peroxy-dicarbonates, alkyl per-esters, alkyl hydroperoxides, per ketals, dialkyl peroxides or 35 ketone peroxides. Dialkyl pero cides, such as di-tert-butyl peroxide, di-tert- amyl peroxide, and alkyl per esters such as tert-butyl peroxy-2-ethylhexanoate or tert-amyl peroxy-2-ethylhexanoate are preferred. The concentration of initiator is used in the range of from 1 5 to 8 wt% and preferably of from 2 to 6 wt%, based on the total mass of the co-monomers. According to the present invention, the hydroxyl functional asymmetric alkyl unsaturated diester is typically produced by reacting the anhydride with an equimolar ratio of 0 an above described alcohol at a temperature of 80°C to 130 °C and preferably in the range of 90 °C to 110 °C. The residual un-reacted anhydride is transformed in di-acid or half ester by means of addition of water or preferably a primary alcohol, such as methanol . The resulting half ester is 5 subsequently reacted with an epoxy compound as listed above at a temperature 80°C to 130°C and preferably in the range of 90 °C to 110°C with optionally 0.05 to 1.0 weight percent of an acid-epoxy reaction catalyst such as stannous octoate type catalyst ( e.g. DABCO T9) .

!0 The hydroxyl functional resins are prepared by addition of a monomer mixture which contains at least 5 to 40 weight percent of an aromatic vinyl monomer or vinyl ether or vinyl ester or a mixture of those vinyl monomers to the hydroxyl functional asymmetric alkyl unsaturated diester. The co-

!5 monomer mixture may also contain acrylic or methacrylic or symmetric diester of maleate monomers as listed above. The reaction is carried out at a temperature of 130 °C to 170° and preferably at 140 °C to 160°C for 5 to 8 hours and preferably 6 to 7 hours . The preferred radical

30 polymerisation initiator is di-tert-butyl peroxide and used in the range of from 1 to 8 wt% and preferably of from 2 to 6 wt%, based on the total mass of monomers. The most preferred, for low colour produced resin is di-tert-amyl peroxide and used in the range of from 1 to 8 wt% and 5 preferably of from 2 to 6 wt%, based on the total mass of monomers . The radical polymerisation initiator, as well known in the art, is added in at least two stages or gradually. The hydroxyl functional resins prepared according to the above process are characterised by a residual concentration 5 of the hydroxyl functional asymmetric alkyl unsaturated diester lower than 12 percent by weight of the initial charge of the diester. The copolymerization can be carried out in bulk or in a solution of the co-monomers in an inert solvent, e.g. in 0 amounts of from 0 to 40 weight %, preferably from 5 to 25 weight %. Suitable inert solvents that can be used are: alkyl acetates such as butylacetate, alkyl aromatics such as xylene or a mixture thereof . Suitable cross-linking agents to be applied in the 5 coating compositions of the present invention can be selected in general from blocked isocyanate groups containing compounds. Polyisocyanate may be aliphatic, cycloaliphatic, or heterocyclic and may be substituted or unsubstituted. For curing above 100°C the polyisocyanate is 0 preferably a fully-capped (blocked) polyisocyanate with substantially" no free isocyanate groups. The polyisocyanate is preferably aliphatic. Diisocyanates are preferred, although higrier polyisocyanates can be used in place of or in combination with diisocyanates. Suitable isocyanates for 5 curing at room temperature are described in "Polyurethanes for coating" (Ed. By Dr. Ulrich Zorll, author Dr. Manfred Bock; pages 3-09 to 150) which is included herein by reference. The cross-linking reaction can be catalyzed by addition of an organometallic compound, such as tin ι0 compounds, and if desired tertiary amines, preferably diethyl ethanol amine . Examples of appropriate tin compounds are di-butyl tin di-laurate, di-butyl tin acetate and di-butyl oxo-tin. Other types of hereinbefore specified cross-linking agents !5 can be formaldehyde adducts derived from urea, melamine and benzoguanamine , or the etherified formaldehyde-amine adducts. Preferred cross-linking agents for the formaldehyde adducts are the melamine- formaldehyde adducts partially or completely etherified with aliphatic alcohols having 1 to 4 carbon atoms. Examples of such commercially available curing agents are: MAPRENAL MF900, VMF3296 and CYMEL 303, 327 and 1158 curing agents (MAPRENAL, VMF and CYMEL are trademarks) . The above cross-linking reaction can be catalyzed by addition of an strong acid, such as phosphoric acid, para toluenesulfonic acid and the like.

More preferred embodiments of said coating compositions are those, comprising copolymers obtainable from (i) 5 to 50 weight % of the unsaturated hydroxydiester of this invention, (ii) 5 to 45 weight % of a vinyl monomer, (iii) 0 to 30 weight % of acrylic or methacrylic esters and symmetric diester of maleate or fumarate monomers, (iv) 1 to 8 weight % of a radical polymerisation initiator, (v) optionally an inert organic solvent.

!0 Preferred hydroxyl containing copolymers have an average molecular weight (M_n) from 1,000 to 5,000.

It will be appreciated that another aspect of the present 15 invention is formed by the hydroxyl containing copolymer to be used in coating compositions, which provide a fast drying time of the said coating, while maintaining other relevant physical properties such as hardness, MEK resistance, VOC flexibility, scratch resistant and acid resistant coating 30 films after curing. Another aspect of the present invention is formed by the cured coating films derived from the hereinbefore defined coating compositions and applied on a shaped substrate, and more in particular on automotives. Test description and analytical methods: Acid value: according to ISO 3682-96

Drying test : Dust free time: The dust free time is measured by falling from a distance of 5 cm a piece of cotton wool onto the top of the coated panel . When the panel is turned upside down and the cotton falls off, the coating is assumed to be dust free. The time is noted. Tack free time: The tack free time is the drying time (at room temperature) that is needed before a Koenig hardness of 20s is achieved. The pendulum hardness test ISO 1522-73 is used. 5 Molecular weight determination: General : General information on liquid exclusion chromatography can be obtained from ASTM D3016; standard practice for use of liquid exclusion chromatography terms ,0 and relationships. Scope : This method describes the determination of the molecular size distribution characteristics of acrylic copolymer resins. For the correlation, the following standars are used: !5 polystyrene standards, covering the relative molecular mass range from about 5000 to 3000000 the following Toya Soda standars are recommended: A-5000, F-l, F-2, F-4, F-10, F- 20, F-40, F-80, F128, F-288 and 1-phenylhexane . Method condi tions :

50 - PL (Polymer Laboratories) columns were used. - Short column set : small pre-column and 3 columns of 30 cm PL-gel 5 micron: mixed C + 2X mixed D - Column oven at 40°C - Mobile phase: THF at 0.8ml/min - UV- and RI detector Samples were dissolved in THF. Mn, Mw, Peak and Mwd are 5 quoted.

Solids content: according to ASTM D2369-92 Volatile organic content (VOC) : according to ASTM D 3960-96 Pendulum damping test (Koenig hardness) : according to

ISO 1522-73 (E) or DIN 53 157

L0 Resistance of coatings against acid Method summary: The acid resistance is determined by exposing the film to droplets of 0.6ΪKT sulphuric acid for 30, 60 and 90 minutes at 50°C and assessing the resulting damage to the film. Minimum score (per spot) is 0 (very poor) , maximum score is L5 10 (not affected) , and the three scores are then added together. The acid resistance was measured on coatings cured at room temperature and cured at 60°C for 30 minutes. MEK resistance (MEK) Summary of the method: A piece of cotton wool, soaked with MEK, is rubbed over the 20 coating (using a pressure of around 2 kg) . If the coating surface has been rubbed one hundred times up and down without showing any damage, the coating is said to be fully cured. If, after; x "double MEK rubs", the coating has been destroyed on a full line going from the top to the bottom 25 of the panel, the coating is said to fail after x "double MEK rubs". The MEK resistance was measured on coatings cured at room temperature and cured at 60°C for 30 minutes. Measurement of the resistance to cracking-rapid deformation (Impact test /Kugelschlagprufung/ Falling Weight test) : 30 according to ISO 6272-93 (E). Measurement of resistance to cracking-gradual deformation (Erichsen Slow Penetration test or Cupping test) According to: ISO 1520-73 (E) Viscosity of Newtonian systems using a Brookfield viscometer: ISO 2555-89. The invention is illustrated in more detail in the following 5 examples, however without restricting its scope to these specific embodiments. All percentages are contents by mass weight and all parts are parts by mass weight, unless expressly stated otherwise. EXAMPLES

L0 Synthesis of the asymmetric hydroxyl functional diester maleate derivatives. Example la MIBC diester Equipment : Glass reactor equipped with an anchor stirrer, reflux condenser and nitrogen flush.

L5 Manufacturing procedure: Maleic anhydride was reacted with methyl isobutyl carbinol (MIBC) in an equimolar ratio at a temperature between 90 and 110°C, to form a maleate monoester in presence of 5.9 wt % butyl acetate. The reaction was continued until .0 conversion of the anhydride had reached at least 90 mole% (Conversion of the anhydride is monitored by acid-base titration.) . Methanol was added to open the remaining anhydride in a 1.2/1 molar ratio of methanol/anhydride and the reaction was continued for 30 minutes.

15 CARDURA ElOP was fed to the reactor together with DABCO T9 (0.07 wt%) over a period of 30 minutes. CARDURA E10P glycidyl ester was added in an equimolar ratio to the remaining acid in the obtained reaction mixture whilst keeping the temperature between 85 and 120°C. The reaction

50 mixture was then additionally kept at 95°C for 90 minutes. Example lb MIBC diester Equipment : Glass reactor equipped with an anchor stirrer, reflux condenser and nitrogen flush. Manufacturing procedure : Maleic anhydride was reacted with methyl isobutyl carbinol (MIBC) in an equimolar ratio at a temperature between 90 and 110°C, to form a maleate monoester in presence of 5.9

5 wt % butyl acetate. The reaction was continued until conversion of the anhydride had reached at least 90 mole% (Conversion of the anhydride is monitored by acid-base titration . ) . Methanol was added to open the remaining anhydride in a 1.2/1 molar ratio of methanol/anhydride and

.0 the reaction was continued for 30 minutes. CARDURA ElOP was fed to the reactor over a period of 30 minutes. CARDURA E10P glycidyl ester was added in an equimolar ratio to the remaining acid in the obtained reaction mixture whilst keeping the temperature between 85 .5 and 120°C . The reaction mixture was then additionally kept at 95°C for 90 minutes. Example 2 TMCH diester Equipment : See example la Manufacturing procedure :

!0 The manufacturing procedure was similar to that of example la except that the alcohol used was 3,3,5 trimethyl cyclohexanol (TMCH) and 5 wt% of butyl acetate was used. A post -cooking of 234 minutes at 90°C.

15 Example 3 TMCH diester Equipment : See example la Manufacturing procedure : The manuf cturing procedure was similar to that of example lb except that the alcohol used was 3,3,5 trimethyl cyclohexanol !0 (TMCH) and 5 wt% of butyl acetate was used. A post-cooking of 234 minutes at 90°C. Example 4 DIBC diester The manufacturing procedure was similar to that of example 1 except that the alcohol used was di-iso-butylcarbinol (DIBC) and 7.4 wt% of butyl acetate was used. A post cooking of 105 minutes at 120°C was applied. Example 5a IPA diester

Maleic anhydride was reacted with isopropyl alcohol (IPA) in a ratio MA/IPA 1/1.2 at 90 - 110°C to form a maleate monoester in presence of 2.1 wt % butyl acetate. The reaction was continued until conversion of the anhydride had reached at least 90 mole% (Conversion of the anhydride is monitored by acid-base titration.) . Excess of IPA was then removed via distillation.

CARDURA ElOP was fed to the reactor together with DABCO T9 (0.07 wt%) over a period of 30 minutes. CARDURA ElOP was added in an equimolar ratio to the remaining acid in the system whilst keeping the temperature between 90 and 100 °C. The system was then hold further at 105 °C for 105 minutes.

Example 5b IPA diester

Maleic anhydride was reacted with isopropyl alcohol (IPA) in a ratio MA/IPA 1/1.5 at 90 - 110°C to form a maleate monoester. The reaction was continued until conversion of the anhydride had reached at least 90 mole% (Conversion of the anhydride is monitored by acid-base titration.) .

Methanol was added in a 1.2/1 molar ratio methanol/anhydride the reaction mixture at 90° for further 30 minutes.

CARDURA ElOP was fed to the reactor over a period of 30 minutes. CARDURA ElOP was added in an equimolar ratio to the remaining acid in the system whilst keeping the temperature between 90 and 100°C. Excess of IPA was then removed via distillation, temperature up to 125°C.

Synthesis of the hydroxyl functional resins Example 6 MIBC resin

Composition: see Table 1,

Maleate diester used is described in Example la.

Equipment: Glass reactor equipped with an anchor stirrer, reflux condenser and nitrogen flush.

Manufacturing procedure :

The reactor was flushed with nitrogen and the initial reactor charge was heated to the polymerization temperature of 145°C. This first charge of Di ter-butylperoxide was then added in one shot. Immediately after this addition, the monomers- initiator mixture was dosed continuously to the reactor in 330 minutes at the same temperature. The monomer addition feed rate was halved during the last hour of monomer addition. After completion of the monomer addition, the third charge of Di ter-butylperoxide was then fed together with a small amount of the butyl acetate to the reactor in 30 minutes. The reactor was kept at this temperature for 60 more minutes. Finally, the polymer was cooled down and diluted with the remaining butyl acetate . Example 7 MIBC resin

Maleate diester used is described in Example la.

Manufacturing procedure : Same as example 6 except that the polymerization temperature was 150°C.

Example 8a TMCH resin

Maleate diester, used is described in Example 2.

Manufacturing procedure : Same as example 6 except that the polymerization temperature was 150°C. Color, Pt/Co: 125 Example 8b TMCH resin 5 Maleate diester, used is described in Example 3. Equipment: Glass reactor equipped with an anchor stirrer, reflux condenser and nitrogen flush. Manufacturing procedure : Same as example 8a except that radical intiator is di- LO tert-amyl peroxide (DTAP) and that the polymerization temperature was 140 °C. Color, Pt/Co: 50 Example 9 DIBC resin Maleate diester, used is described in Example 4.

L5 Equipment: Glass reactor equipped with an anchor stirrer, reflux condenser and nitrogen flush. Manufacturing procedure : Same as example 6 except that the polymerization temperature was 150°C.

10 Example 10a IPA resin Maleate diester, used is described in Example 5a. Equipment: Glass reactor equipped with an anchor stirrer, reflux condenser and nitrogen flush. Manufacturing procedure :

>5 Same as example 6 except that the polymerization temperature was 150°C. Color, Pt/Co: 92 Example 10b IPA resin Maleate diester, used is described in Example 5b. Equipment: Glass reactor equipped with an anchor stirrer, reflux condenser and nitrogen flush.

Manuf cturing procedure : Same as example 10a except that radical intiator is di- tert-amyl peroxide (DTAP) and that the polymerization temperature was 140 °C.

Color, Pt/Co: 54

COMPARATIVE hydroxyl functional resins A/ Synthesis of the asymmetric hydroxyl functional diester maleate derivatived from primary alcohol. Comparative Example 1 Neodol 45E

Equipment : See example 1 The manufacturing procedure was similar to that of example 1 except that the alcohol used was Neodol 45E, a C14-C15 linear primary alcohol from Shell chemicals except that the reaction temperature was between 50 and 70°C. The conversion of the anhydride reached a value above 98%.No methanol was added before the addition of CARDURA ElOP. A post-cooking of 60 minutes at 100°C was used. Comparative Example 2 propanol

Equipment : See example 1 Manufacturing procedure : Maleic anhydride was reacted with propanol, in a ratio MA/propanol 1/1.5 at 50°C for 3 hours and then for 1 hour at 80°C to form a maleate monoester in presence of 9.1 wt % butyl acetate. CARDURA ElOP was fed to the reactor together with DABCO T9 (0.07 wt%) over a period of 30 minutes. CARDURA ElOP was added in an equimolar ratio to the remaining acid in the system whilst keeping the temperature between 90 and 100 °C. The system was then hold further at 80 °C for 90 minutes. The reaction temperature was then increased to 140°C and left for 120 minutes to remove excess of propanol. B/ Comparative hydroxyl functional resins

Composition see Table 2

Comparative Example 3 acrylic polyol resin

MACE resin

Manufacturing procedure : The reactor was flushed with nitrogen and the initial reactor charge was heated to the polymerization temperature (160°C) . The remaining monomer-initiator mixture was fed continuously to the reactor in 5 hours at this temperature. The additional initiator was then fed together with a small amount of the butyl acetate to the reactor in 30 minutes. The reactor was kept at this temperature for 30 more minutes. Finally, the polymer was cooled down and diluted with the remaining butyl acetate. Comparative Example 4 Neodol resin

Maleate diester used is described in comparative example 1.

Manufacturing procedure : The reactor was flushed with nitrogen and the initial reactor charge was heated to the polymerization temperature (150°C) . This first charge of Di- ter-butylperoxide was then added in one shot . Immediately after this addition, the monomers-initiator mixture was dosed continuously to the reactor in 5.5 hours at the same temperature. The monomer addition feed rate was halved during the last hour of monomer addition. After completion of the monomer addition, the third charge of Di-ter-butylperoxide was then fed together with a small amount of the butyl acetate to the reactor in 30 minutes. The reactor was kept at this temperature for 60 more minutes. Finally, the polymer 5 was cooled down and diluted with the remaining butyl acetate. The polymerization temperature was 150°C. Comparative Example 5 propanol resin Maleate diester used is described in comparative example 2. Equipment: Glass reactor equipped with an anchor stirrer, L0 reflux condenser and nitrogen flush. Manufacturing procedure : The reactor was flushed with nitrogen and the initial reactor charge was heated to the polymerization temperature (150°C) . This first charge of Di-ter-butylperoxide was then added in

L5 one shot. Immediately after this addition, the monomers- initiator mixture was dosed continuously to the reactor in 5.5 hours at the same temperature. The monomer addition feed rate was halved during the last hour of monomer addition. After completion of the monomer addition, the third charge of

JO Di-ter-butylperoxide was then fed together with 25 wt% of the butyl acetate to the reactor in 30 minutes. The reactor was kept at this temperature for 30 more minutes. Finally, the polymer was cooled down and diluted with the remaining butyl acetate. The polymerization temperature was 150°C.

TABLE 1 : Resin composition and properties according to the invention.

Example 6 7 8a 9 10a MIBC MIBC TMCH DIBC IPA

Initial Reactor

Charge xylene 4 4 4 4 4 Maleate diester 41.9 41.9 41.8 40.7 40.7

Initator start DTBP 0.4 0.4 0.4 0.4 0.4

Monomer feed Xylene 7 7 7 7 7 Hydroxyethyl methacrylate 20.1 20.1 20.1 20.1 20.1 Styrene 20 20 20 20 20 Methyl methacrylate 19.2 19.2 19.2 19.2 19.2 Di ter butyl peroxide 3.6 3.6 3.6 3.6 3.6

Post cook DTBP 1 1 1 1 1

Butyl acetate 40 40 40 40 40

Total intake 157.2 157.2 157.1 156 156

Solids content 59.3 60.3 60.1 60.1 57.4 (intakes : all expressed in part by weight)

TABLE 2 : Comparative examples : resin composition and properties . Comparative Example 3 4 5 MACE Neodol propanol Initial Reactor Charge Cardura EIOP 30 - - xylene 2.5 4 4 Maleate diester 0 43.0 39.6 Initator start DTBP 0.4 0.4 0.4 Monomer feed Xylene 8.5 7.0 7.0 Methacrylic acid 10.7 - - Hydroxyethyl methacrylate 16.0 5.1 20.1 Styrene 22.0 30.0 20.0 Methyl methacrylate 21.3 24.2 19.2 DTBP 3.6 3.6 3.6 Post cook DTBP 1 1 1 Butyl acetate 30 40 40 Total intake 146.0 158.3 154.9 Solids content 62.5 61.6 55.2 (intakes : all expressed in part by weight) Example 11 Emulsion polymerization Example of colloid stabilized latex formulation Initial reactor charge parts weight Demineralised water: 413.5, Rhodacal DS10 :1.5, Borax :2.5, 5 Acetic acid:l, Potassium persulphate: 1, Cellosize QP300: 20 Monomer pre-emulsion Demineralised water : 167.5, Borax : 2.5, Acetic acid : 1.0, Rhodacal DS10 :1.5, Disponil O250 (10% aq.sol.): 200.0, VeoVa 10 : 100.0, Hydroxydiester of example 5b: 100.0 , Vinylacetate : L0 800.0 Initiator solution Demineralised water: 120.0, Potassium persulphate: 2.3 Supliers: Rhodacal DS10 Anionic surfactant supplied by Rhodia, Cellosize QP300 Hydroxyethyl cellulose from Dow .5 chemicals, Disponil O250 Non-ionic surfactant supplied Henkel, VeoVa 10 from Resolution Performance Products, Borax sodium tetraborate decahydrate. Procedure A stable monomer pre-emulsion was prepared by adding the 0 monomers to the vigorously stirred aqueous phase, according to the above recipe. The initial reactor charge was heated to 60 °C under a nitrogen stream. When the temperature of 60 °C was reached, the nitrogen stream was stopped and 10% of the monomer pre-emulsion was added to the reactor. When this 5 charge had polymerized, reflux of vinyl acetate stopped and the temperature normally reached 76°C. Then, the remainder of the monomer pre-emulsion was gradually added over a period of 3 hours maintaining a temperature of 76°C. The initiator solution was added simultaneously via a separate line. The 0 addition time was fifteen minutes longer to improve monomer conversion. After monomer addition, a post-cooking treatment of 2 hours at 80°C was applied. Finally, the latex was cooled to 30°C. This latex had a solid content of 53 weight percent and a pH of 4.

Cured coating compositions Clear lacquers were formulated from the acrylic polymers by the addition of polymer isocyanate curing agent (Desmodur N 3600) in a l/l OH/isocyanate ratio and a cure catalyst (Di- butyl tin di-laurate) at a concentration of 0.01%, based on resin and isocyanate content. Solvent, butyl acetate was added to dilute at an applied viscosity of 100 m Pas. The coating properties of the formulations based on the resins according to the invention are reported in Table 3 and in Table 4 for the comparative examples .

TABLE 3 : Coating properties of the resins according to the invention Formulation A B C D E Resin of example 6 7 8a 9 10a VOC g/l * 411 404 404 402 432 Dust free time, minutes 41 60 20 85 23 Tack free time, RT, hours 14.5 15 12 16.5 12 Koening hard, RT, after 4 hrs, s tacky tacky 7 tacky 6 Koening hard, RT, after 168 hrs, s 172 176 177 176 183 Direct impact strength, inch. lb nd 40 35 nd >100 Slow penetration, mm nd 8.2 8.7 nd 8.7 MEK resistance, double rubs >100 >100 >100 nd >100 Acid resistance 28 25 25 nd 26

* of the coating composition as applied at a viscosity of 100 mPas .

TABLE 4 : Coating properties of the comparative resins Comparative Formulation F G H Resin of Comp. example 3 4 5 VOC g/l * 383 433 451 Dust free time, minutes 71 95 35 Tack free time, RT, hours 25 30 14 Koening hard, RT, after 4 hrs, s tacky tacky no Koening hard, RT, after 168 hrs, s 105 134 9 Direct impact strength, inch. lb nd 160 160 Slow penetration, mm nd 8 8.3 MEK resistance, double rubs >100 >100 >100 Acid resistance 29 26 24

* of the coating composition as applied at a viscosity of 100 mPas

Claims

FAST DRYING COATING COMPOSITION COMPRISING AN UNSATURATED HYDROXYDIESTER C L A I M S 1. A curable coating composition comprising an unsaturated hydroxydiester characterised in that it comprises at least the reaction product of a secondary alcohol and unsaturated anhydride or acid, which has been subsequently reacted with a 5 saturated glycidyl ester.

2. The curable coating composition of claim 1, characterised in that the unsaturated hydroxydiester is radically copolymerized with a vinyl monomer and ethylenically unsaturated copolymerizable compound and that said copolymer

LO is cross-linked with curative for hydroxyl functionality.

3. An unsaturated hydroxydiester characterised in that it comprises the reaction product of a secondary alcohol and maleic or citraconic anhydride or acid followed by the reaction with a glycidyl ester.

L5

4. The compounds of claim 3 characterised in that the glycidyl ester comprise an alkyl glycidyl ester correspond to the general formula (I) ,

R O R'-C—COO—CH,—CM CM_» (I) in which R,R',R" are independently hydrogen or aliphatic alkyl radicals of 1 to 10 carbon atoms, the total carbon atoms of the three radicals (R+R' +R" ) being between 1 to 20, preferably between 3 to 13. 5. The compounds of claim 3 characterised in that the alcohol is a secondary alcohol selected from iso-propanol, sec- butanol, methyl isobutyl carbinol, di-iso-butyl carbinol, tridecyl/isodecyl alcohol, isobornyl alcohol, cyclohexanol, 3,3,

5 trimethyl cyclohexanol, tetrahydrofurfuryl alcohol , or a mixture thereof .

6. The compounds of claim 3 characterised in that the glycidyl ester is selected from 1-methylpropionic glycidyl ester, 1-dimethyl-propionic glycidyl ester (pivalic glycidyl ester) , iso-butyric glycidyl ester, 1-methyl-propionic 5 glycidyl ester, 1-methyl-butyric glycidyl ester, 1-dimethyl- butyric glycidyl ester, Versatic acid glycidyl ester, neodecanoic glycidyl ester and other glycidyl ester of alkanoic acids and mixture thereof.

7. A process to prepare a resin by radical polymerisation O comprising: (i) 5 to 50 weight % of the unsaturated hydroxydiester of claim 3, (ii) 5 to 45 weight % of a vinyl monomer, (iii) 0 to 30 weight % of acrylic or methacrylic esters and .5 symmetric diester of maleate or fumarate monomers, (iv) 1 to 8 weight % of a radical polymerisation initiator, (v) 0 to 40 weight % an inert organic solvent, characterised in that (i) is charged in the reactor at a 70 to 100 weight % of the required quantity before adding the !0 co-monomers (ii) , (iii) and the catalyst (iv) .

8. A process to prepare a resin by emulsion radical polymerisation comprising combining in water: (i) 5 to 30 weight % of the unsaturated hydroxydiester of claim 3, 5 (ii) 20 to 95 weight % of a vinyl monomer, and (iii) 0 to 75 weight % of acrylic or methacrylic esters and symmetric diester of maleate or fumarate monomers.