MXPA96005842A - Moisture-curable coating composition - Google Patents

Abstract

The present invention discloses a coating composition comprising an organic compound having at least two acetoacetate or acetamide groups or a combination thereof and a metal oxide from group IIa of the periodic table of elements, said metal preferably being calcium or magnesium;the composition can also comprise a compound having at least two alpha,a-ethylenically insaturated groups and optionally a catalyst for the reaction of the acetoacetate groups and/or acetamide groups with alpha,a-ethylenically insaturated groups.

Description

COMPOSITION T) E CURABLE COATING IN HUMID MEMORIft DESCRTTIVQ The present invention relates to a coating composition comprising a metal compound and an organic compound comprising at least two acetoacetate groups or acetamide groups or a combination of the two groups. From the specification of the British patent No. 1 407 002, a composition is known wherein, among other things, the formation of chelatadoree from epoxy acetoacetate-functional resins and metal alcolates, v.gr, calcium alcolate is described. However, the presence of water is included here because it would cause hydroxides to form, thus avoiding chelation from the collection site. Any water of crystallization that can be present in the used compounds is removed by heating them. In other words, there should be no water present in the healing. A further disadvantage is the release of alcohols when the cure is performed. The Dournal of Coatings Technology, Vol. 52, No. 661 (February 1980) on pp. 73-87 describes chelation as emulsion interlacing media. The emulsion of a functional acetoacetate compound is chelated using, among other things, calcium chloride and magnesium chloride, with the use of zinc chloride and zinc acetate being preferred. Said article refers to a water-based system or dirnetilforrnamida. However, the systems described herein have a long cure time, and in addition the salts can have a negative effect on the water resistance of the final film. Furthermore, water-based sites have the disadvantage that acetoacetate-functional compounds have limited hydrolysis stability, which means that the reactivity is largely lost during storage. The object of the invention is to provide a coating composition without the aforementioned disadvantages and of which other properties are also satisfactory. The coating composition is characterized in that the metal compound is the oxide of a metal of group II a of the periodic table. Surprisingly, it has been found that a coating composition comprising an organic compound comprising at least two acetoacetate groups or acetarnide groups in a combination of the two groups cures very quickly in the presence of the metal oxide of group Ia of the periodic table . Especially especially suitable metals of group Ia of the periodic table in this connection are magnesium and calcium. GB-fl-2 235 928 describes a road marking powder composition consisting of an organic binder with calcium oxide added thereto, to which water has to be added immediately before it is applied. The addition of the water discards an exothermic reaction, causing the binder to melt and render the composition processable. No mention is made of an acetoacetate- or acetarnide-functional compound. According to the invention, at least two acetoacetate groups or acetarnide groups or a combination of said groups is present per organic compound. An "organic compound" herein is defined as a compound of hydrocarbons that does not contain metal atoms. The organic compound can be a monomer or a polymer. The polymeric compound preferably has an A above 450, and preferably between 500 and 5000, most preferably still between 500 and 2000. Organic compounds containing acetate groups can be synthesized by reacting polyhydroxy-functional compounds with diketene, e.g. , as described in KL Today and C.H. Carder, "Polyena ine Coating I. For ulation of Coatings and Determination of Film Properties", Journal, of Paint Technology. Vol 46, No. 591 (fibril 1974), 70-75. Also suitable are acetoacetate-functional organic polymers derived therefrom, as described, inter alia, in C.H. Carder and H.O. Colornb, Jr., "Polyenamine Coatings II, Chemical riethods of I proving Film Properties," Journal of Paint Technology. Vol 46, No. 591 (ftbril 1974), 76-81. Also suitable are organic acetoacetate-functional compounds obtained by copolymerizing acetoacetate-unitary monomers with unsaturated onomers, e.g., in EP-B-0199 and in UO 91/09910. Among others, the reaction products of acetoacetoxyethyl methacrylate and one or more alkyl methacrylates, hydroxy-functional alkyl methacrylates, hemoxy-functional alkyl methacrylates and optionally other oc, β-ethylenically unsaturated compounds are suitable. In this connection mention may be made of butyl methacrylate, methyl methacrylate, hydroxyl methacrylate, glycidyl methacrylate and styrene. It is further possible to employ organic acetoacetate-functional compounds prepared by transesterification of polyhydroxyl functional monomers or polymers with acetoacetate-functional esters as described e.g., in EP-P-0 227 454. Suitable organic compounds in this connection are dipropylene glycol diacetoacetate, 1,6-hexanediol diacetoacetate and 1,5-pentanediol diacetoacetate. The transferase product of esters of pentanotriol and acetoacetate is also suitable. Instead of or in addition to at least two functional organic acetoacetate compounds, organic compounds comprising at least two acetarnide groups or combinations of said groups can be used. Examples of organic compounds comprising acetarnide groups are those constructed from the reaction products of diketene and ethanolarni to: O 0 II II HO- -N- -C- -C- -CH to H, Hs H Hs or a compound of the following structure: 0 CHa 0 0 HO C C N C C C CHS H Ha The molar ratio of said acetoacetate groups and / or acetamide groups to metal oxide should be from about I to about 0.5 to 10 preferably one mole of acetoacetate groups and / or acetamide groups of 0.5 to 7 moles of metal oxide. In addition to the organic acetoacetate and / or acetamido or functional compounds mentioned above, the coating composition, if desired, may comprise organic mononane monoacetoacetate or monoacetarni functional as reagent thinners, eg, ethyl acetoacetate, butyl acetoacetate. tertiary or acetyl acetoacetate. Also, oligomers and polymers containing no acetoacetate group or acetamide group can be present as, for example, adhesion promoters or polymeric softening agents, e.g., hydroxyl functional polyesters, epoxide reactions, alkoxysilanes and polyisocyanates. It is also possible to add amines that can be blocked or not, e.g., polyketimines. This is described, among others, in K.L. Today and C.H. Carder, "Polyenamine Coating I. For ulation of Coatings and Determination of Film Properties", Journal of Paint Technology. Vol 46, No. 591 (April 1974), 70-75. However, compounds comprising at least 2 α, β-ethylenically unsaturated groups are preferably present, e.g., as described in EP-H-0 1151 697. In general, the acryl-functional compounds are satisfactory. Especially suitable are, for example, reaction products of hexamethoxyrnethylmelarnine and 3.4, or 5 moles of hydroxyluryl acrylate (the latter compound is available commercially from Cros Chemicals under the trade name Setacrure® 590), hexarnetoxirnetylrnelarnine with 2.5 or 5 moles of a reaction product of 2 moles of caprolactone and 1 mole of hydroxyethyl acrylate (the latter compound is commercially available from Rkcros Chemicals under the tradename Setacure® 591), propoxylated glycerol triacrylate, ethoxylated detrimethylol triacylate and aromatic urethane diacrylate ( especially available from Plkcros Chemicals under the commercial names of fictylane * 432 and 430 and Setacure® 567, respectively). The molar ratio of acetoacetate groups and / or acetamide groups to α, β-ethylenically saturated groups is from about 1 to about 0.5 to 2, preferably 1 mole of acetoacetate groups and / or aceta ina groups to 0.8 to 1.5 moles of groups a, ß ~ ethylenically unsaturated.

In quenching compositions, compounds are formed in at least two α, β-ethylenically unsaturated groups, optionally one or more strong bases may be present as catalysts for the reaction between α, β-ethylenically unsaturated groups and acetoacetate groups and / or acetamide groups . Highly satisfactory results have been obtained in this connection using diazabicycloundecene, diazabicyclo-nonene, tetra-ethylguanine, tetramethylammonium hydroxide or biazabicyclooctane (DABCO). Alternatively, instead of or in addition to said strong bases, other catalysts may be present for the reaction of the acetoacetate groups or acetarnide groups with the α, β-ethynonically unsaturated groups, e.g., epoxy compounds which in combination with DflBCO produce strong bases. These and other catalysts described in EP-A-0 160 824. Also satisfactory is a mixture of possible catalysts such as described in EP-A-0 326 723. In addition, it is possible to employ onium salts, such as phosphonium and ammonium, as well, to say the least, phosphines or catalysts. An amount of about 1-10% by weight of catalyst, calculated on the acetoacetate and / or acetarnidation organic compounds and the compounds comprising at least two α, β-ethylated unsaturates, is to be used. The use of 2-6% by weight of catalysts is preferred. The reaction of acetoacetate groups and / or acetamide groups are groups a, ß-ethylenically unsaturated proceeds to the reaction of the acetoacetate groups and / or acetamide groups with the metal oxide. The first reaction provides the final coating with superior flexibility. The reaction of the acetoacetate groups and / or acetamide groups with the metal oxide will generally proceed more rapidly than the acetoacetate groups and / or acetamide groups with the α, β-ethylene groups unsaturated. In addition to the above-mentioned composite films, the coating composition may comprise the usual coating composition compounds, such as fillers for rheology fillers such as talc and barium sulfate, pigments such as titanium oxide as well as, optionally, moisture scavengers. . The water required for rapid curing can be added immediately prior to the application of the coating composition. At most, one mole of water can be added per one mole of metal oxide, however, in many cases the moisture that is present in pigments or fillers, or the humidity of the air with which the composition comes in contact after being applied, it will be enough to cure the composition. Highly practical in this connection is a system made of two compositions. Composition A will comprise, to say the least, the organic acetoacetate compound and / or acetamido-functional groups and any solvents present, reagent thinners and other compounds already described. Composition B will comprise, to say the least, the metal oxide, pigments and fillers, together with the compounds described at the beginning comprising at least two α, β-ethylenically unsaturated groups. The presence of crystallization water, if any, in composition B has no adverse effect on the reactivity of the two-component system. The two compositions can be combined before processing the coating composition. If desired, a small amount of water can be added. Alternatively, if desired, the metal oxide can be added to a composition comprising all the components already described before application. In this case, preferably metal oxide powder having particles smaller than about 100 microns is used. The coating composition can be applied in any desired manner, e.g., by brushing, spraying, roller coating, flow coating and using a filling knife. The coating composition of the present invention can be applied to any substrate, for example, plastic metal, wood or glass. Due to its fast drying, the coating composition is highly suitable for use when the application of thick layers is required. A particular case is the paste for automotive repair, especially in the repair work of automobiles, that is, to repair automotive vehicles and transport vehicles or for the finishing of large transport vehicles, such as trains, tractocarniones, buses and airplanes.

EXPERIENTIAL SECTION EXAMPLE i To an organic acetoacetate-functional compound (binder A) was added 20 parts by weight (dp) of calcium oxide. Then, a small amount of water was added and the cure time was measured. Used as a binder A functional acetoacetate was the transesterification product of pentaerythritol and ethyl acetoacetate, which was prepared in the following manner. In a reaction vessel equipped with a DestStar distillation apparatus, 340 grams of pentaerythritol, 1460 grams of ethyl acetoacetate and 1000 ppm of dibutyltin oxide were mixed and heated to reflux temperature, after which care was taken to ensure that the temperature did not exceed 170 ° C. At the end of the reaction, the mixture was cooled and the residual ethyl acetoacetate was distilled under high vacuum. Table 1 below gives a list of drying times with and without the addition of a small amount of water. The quantities in table 1 are in parts and weight.

TABLE 1 EXAMPLE. 2 The acetoacetate-functional binder was a copolymer of acrylate, butylacrylate, styrene and acetoacetoxyethyl acetoacrylate prepared in the following manner. In a reaction vessel, 395.9 g of ethyl acetoacetate were introduced and heated to 160 ° C, with an inert gas being passed over it. Over a period of 3 hours a mixture of 1691.3 g of acetoacetoxyethyl methacrylate, 708.5 grams of butyl acrylate, 116.7 grams of styrene, 253.1 grams of ter-butyl peroxy-3,3,5-trimethyl hexanoate (Trigonox® 42S ex Akzo Nobel), and 53.6 grams of ethyl to ethyl acetoacetate already present. Afterwards, everything was cooled to 140 ° C. Then, 12.7 grams of Trigonox 42S and 36.0 g of ethyl acetoacetate were added. After 30 minutes the same amounts of Trigonox® and ethyl acetoacetate were added again, and then once again after another 30 minutes. Subsequently, it was flushed with 31.3 grams of ethyl acetoacetate. After 30 minutes the reaction product was cooled and filtered. The resulting reaction product, binder of, had the following characteristics: Tg = 269K, end = 1285, Pm = 3448, 78% solids solvent: ethyl acetoacetate, the equivalent weight of the resin solution was 275 g / equiv. of acetoacetate, viscosity: 2.5 Pas The following two formulations were prepared and evaluated. The amounts are parts by weight.

Formulation 1 Formulation 2 composition n Composition A Binder B 19.98 Binder B 18.23 DBU3) 2.10 EpikoteR 828 * 0 3.56 Titanium dioxide 4.33 Titanium dioxide 4.22 Talcum 23.50 Talcum 22.94 Barium sulfate 4.53 Barium sulphate 4.39 commons. TI composition B Setacure® 590a) 18.92 Setacure® 590a) 17.27 Calcium Oxide 16.30 Calcium Oxide 18.88 Titanium Dioxide 1.39 Titanium Dioxide 1.66 Talc 7.55 Talc 9.02 Barium Sulphate 1.44 Barium Sulphate 1.72 DABCO) 2.13 I) ex Shell, 2) ex Akcros Chemicals, 10 3) DBU = diazabicycloundecene, 4) DABCO = diazabicyclooctane After the compositions A and B have been mixed, the mixtures are applied to unlined steel with a filling knife and evaluate The resistance to water and solvent is tested after 24 hours of aging at room temperature. .15 The results are listed in Table TI. Table II twenty ? ?

Claims (1)

NOVEPRP BE Lfl INVENTION CLAIMS

1- A coating composition comprising a metal compound and an organic compound comprising at least two acetoacetate groups or acetamide groups or a combination of the two groups, characterized in that the metal compound is the oxide of a metal of the bundle of the Periodic Table. 2. A coating composition according to claim 1, further characterized in that the metal of the bundle is calcium or magnesium. 3. A coating composition according to either or both of the preceding claims, further characterized in that the ratio of acetoacetate groups and / or acetamide groups to metal oxide is 0.5-10 moles. 4. A coating composition according to one or more of the preceding claims, further characterized in that the coating composition comprises a compound comprising at least two α, β-ethylenically unsaturated groups. 5. A coating composition according to claim 4, further characterized in that the compound comprising at least two α, β-ethylenically unsaturated groups is an acryloyl functional compound. 6. - A coating composition according to claim 5, further characterized in that the acryloyl functional compound is a reaction product of hexametoxymethyl elanine and a hydroxyl functional acrylate. 7. A coating composition according to clause 4.5, or 6y further characterized in that the composition comprises a catalyst for the reaction of the acetoacetate groups and / or acetamide groups with the α, β-ethylene-unsaturated groups. 8. A coating composition according to claim 7, further characterized in that the catalyst is diazabicycloundecene, diazabicyclononene, tetrarneylguanidine, tetramethylio onium hydroxide and / or diazabicyclooctane, optionally in combination with one or more hemoxy-functional compounds. 9"~ A coating composition according to one or more of the preceding claims, further characterized in that the organic compound contains at least two acetoacetate groups or acetamide groups or a combination of the two groups is a polymer having an Mn of at least 450. 10. A coating composition according to one or more of the preceding claims, further characterized in that the composition comprises an organic monomer a mono acetoacetate or mono acetarnic-functional. 11. A method for coating a substrate with a coating composition according to one or more of the preceding claims, further characterized in that the coating composition is exposed to air humidity. 12. A method for coating a substrate with a coating composition according to one or more of the preceding claims, 1-10, further characterized in that the water additives are added to the coating composition before its application. 13. A process for coating a substrate with a coating composition according to one or more of the preceding claims, 1-10, further characterized in that the water is added to the coating composition before its application. 14. A two component filler comprising a composition A and a composition B, with composition A comprising an organic compound comprising at least two acetoacetate groups or acetamide groups or a combination of these groups and with composition B comprising the oxide of a metal of the group lia of the Periodic Table. 15. A two-component filler according to claim 15, further characterized in that the metal is calcium or magnesium. 16. A two-component filler according to claim 14, further characterized in that the composition B comprises a compound comprising at least two a, ß-ethylene-unsaturated groups. 17. A two-component filler according to claim 16, further characterized in that the α, β-ethylenically unsaturated groups are acryloyl groups.