CS237082B1 - Alkyd resins - Google Patents

Abstract

The subject of the invention are alkyd resins which contain ester-bound polymeric hydroxyl compounds. The resins are suitable for the preparation of coatings providing coating films with increased toughness and durability. The essence of the invention lies in the fact that from the total amount of ester-bound alcohols the resins contain 1 to 100% by weight of polymeric hydroxyl compounds with an average molecular weight of 500 to 5,000, which are copolymers and/or adducts of hydroxyesters of specified unsaturated carboxylic acids and specified unsaturated hydrocarbons or their unsaturated polymers.

Description

The invention relates to alkyd resins containing ester-linked polymeric hydroxyl compounds.

Alkyd resins are most often prepared by reacting polyalcohols with natural oils or their monocarboxylic acyclic acids and aromatic polycarboxylic acids or their anhydrides. Alkyd resins have excellent film-forming properties, are well pigmented and coatings are capable of curing by air drying or firing. Further refinement of the properties is most often achieved by chemical modification either by reactive monomeric compounds, such as maleinization, styrenation, acrylation, cyclopentadiene, siliconization and uretanization, or by reactive macromolecular substances. Of these, polymeric carboxylic acids and polymeric polyalcohols, which replace some of the starting polyhydric alcohols and polycarboxylic acids, are often suitable. Thus, the synthesis of alkyd resins modified with allyl alcohol-styrene copolymers (U.S. Patent No. 1,520,291, U.S. Patent 3,287,295, British Patent Nos. 1,020,165 and 1,020,166), polyester diols (U.S. Patent 4,222,911) has been described. , polycaprolactones (Japanese patent no.

062854) and epoxy resins (Japanese patent no.

No. 025 941, German Patent No. 1,520,747). A certain disadvantage of these polymeric polyalcohols is the relatively high degree of polymerization, the high content of hydroxyl groups and possibly other reactive functional groups. High molecular weight polyalcohols are difficult to dissolve in alkyd reaction mixtures

237 082 resins, which often gel during the synthesis.

The present invention is directed to alkyd resins based on the products of the reaction of alcohols with carboxylic acids and optionally vegetable oils and processes for their preparation. The resins are prepared from 40 to 65 wt. parts of vegetable oils and / or acyclic carboxylic acids prepared therefrom having a carbon number of 14 to 36, from 20 to 45 wt. % of alcohols containing 1 to 6 hydroxyl groups, at least 1% of which are polymeric alcohols having an average mol. of a weight of 500 to 5,000 from the group of copolymers and / or adducts of hydroxyalkyl esters of unsaturated carboxylic acids having 3 to 6 carbon atoms, containing from 2 to 4 carbon atoms in hydroxyl alkyl, and hydrocarbons having 4 to 12 carbon atoms and 1 to 6 carbon atoms 2 double bonds and from 1 to 30 wt. The process for preparing said alkyd resins may be either a single stage or a two stage process. Starting from the acyclic carboxylic acids themselves prepared from vegetable oils, the process is carried out in a one-step process, comprising a mixture of 40 to 65 wt. parts of acyclic carboxylic acids having a carbon number of 14 to 36 prepared from vegetable oils, 20 to 45 parts by weight of the abovementioned alcohols containing from 1 to 6 hydroxyl groups and 1 to 30% by weight of carboxylic acid; parts of monocarboxylic to tetracarboxylic acids having a carbon number of 7 to 12 are reacted at 180 to 250 ° C in the presence of transesterification catalysts, organic non-reactive solvents or inert gases, if necessary, until the acid number of the product falls below 10 mg KOH.g ^-1 . In the case of starting from vegetable oils or mixtures thereof with acyclic carboxylic acids prepared from these oils, the two-step process is to be carried out by first carrying out at 220 to 250 ° C for 120 to 180 minutes alkolysis of plant alone

237 082 oils with the addition of stoichiometric to all of the above specified alcohols containing 1 to 6 hydroxyl groups, followed by the addition of the monocarboxylic to tetracarboxylic acids having a carbon number of 7 to 12, the possible alcohol residue and any acyclic carboxylic acids having carbon numbers 14 to 36 prepared from vegetable oils and the mixture is reacted at 180 to 250 ° C in the presence of transesterification catalysts, organic non-reactive solvents or inert gases, if necessary, until the acid number of the product falls below 10 mg KOH.g ^-1 .

The alkyd resins of the present invention have some advantages over known polymer-modified polyalcohol products. In particular, the properties of these alkyd resins can be varied to a large extent, both by choosing different compositions and amounts of hydroxyl copolymers or adducts, and by changing the manufacturing technology. The products are characterized by low viscosity and good solubility in common organic solvents. The polymer hydroxyl compounds used have a low hydroxyl group content, they dissolve well in the reaction mixture and react rapidly in the synthesis of alkyd resins. Paints based on them provide high quality coating films with increased toughness and durability.

The alkyd resins mentioned are the reaction products of carboxylic acids and alcohols or derivatives of the following starting materials:

The acid component comprises acyclic, alicyclic and aromatic carboxylic acids or substitution and functional derivatives thereof. The acyclic acids are mainly represented by the monocarboxylic acids of natural oils

237 082 dry (flax, wood, safflower, rapeseed, oiticic, perilla, ricinine, fish), semi-dry (soybean, tall, sunflower, cotton) and dry (coconut, castor, olive, peanut). These acids consist of mixtures of saturated (caproic, caprylic, capric, lauric, myristic, palmitic, stearic, peanut, behenic and lignoceric) and unsaturated acids (oleic, linoleic, linolenic, X- and β-oleostearic, erucic, ricinoleic and 9,11) (ricinene) containing 44 to 24 carbon atoms. It is also possible to use synthetic monolarboxylové saturated acids (neokyseliny, Koch's acid, 2-ethylhexanoic acid, pelargonic), unsaturated (acrylic, methacrylic, crotonic acid), and other acid containing 7 ^to 20 carbon atoms. Acyclic dicarboxylic acids include those having up to 12 carbon atoms, namely saturated (adipic, azelaic, sebacic, dodecanedioic, propantricarboxylic, butanetetracarboxylic) and X, N-unsaturated (maleic, fumaric, citraconic, pyrocinchonic, mesaconic), mesaconic acid, mesaconic acid. alicyclic acids include dimeric acyclic acids forming essentially dicarboxylic acids with 36 carbon atoms 2 aromatic acids are those containing 7 to 12 carbon atoms, either polycarboxylic acids (orthophthalic, isophthalic, terephthalic, tetrachlorophthalic, tetrabromophthalic, tetrahydrophthalic, 4-chloro -tetrahydrophthalic, 3,6-endomethylenetetrahydrophthalic, hexachlorenedomethylenetetrahydrophthalic, hexahydrophthalic, trimellitic, pyromithic) or even monocarboxylic (benzoic, p-tert-butylbenzoic, ra- and p-hydroxybenzoic). Said carboxylic acids or their respective substitution and functional derivatives (anhydrides, esters, partial esters) are used singly or in mixtures with one another in the synthesis of alkyd resins.

The alcohol component of the alkyd resins according to the invention is represented by polymeric hydroxyl compounds having an average molecular weight of 500 to 5,000 or mixtures thereof with monomeric alcohols. Of polymeric hydroxyl compounds

237 082, only copolymers and / or adducts of hydroxy esters of H, γ-unsaturated monocarboxylic acids (acrylic, methacrylic) and dicarboxylic acids (maleic, fumaric, citraconic, pyrocinchon, mesacone, itaconic) with hydrocarbons containing one double bond (butenes, pentenes, hexenes, heptenes, cyclopentenes, cyclohexyls, indenes, coumarone) or two double bonds (butadiene, isoprene, piperylene, dimethylbutadiene, ohloroprene, pentadienes, hexadienes, cyclopentadiene, dicyclopentadiene, cyclohexadiene). Technically important unsaturated hydroxy esters of monocarboxylic acids include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate. Unsaturated dicarboxylic acids also provide, in addition to the dihydroxyesters, ronoalkyl monohydroxyesters, for example monobutyl 2-hydroxyethyl maleate. In addition to the unsaturated monomeric hydrocarbons, unsaturated polymers thereof, including liquid oligomers, co-oligomers, homopolymers and copolymers containing double bonds, are suitable for reaction with these hydroxy esters.

Said polymeric hydroxyl compounds containing at least one hydroxyl group capable of esterifying either all the amount in the alkyd resins of the ester-linked alcohols, or other polyhydric alcohols containing 2 to 6 hydroxyl groups are present. They are glycols (ethylene glycol, propylene glycol, butylene glycols, neopentyl glycol, diethylene glycol, dipropylene glycol, triethylene glycol and other polyalkylene glycols), alicyclic diols (1,2a 1,4-cyclohexanediol, 1,4-bis (hydroxymethyl) cyclohexane), hydrogenated or alkylene oxide 2,2-bis (4-hydroxycyclohexyl) propane, 2,2-bis (4-hydroxyethoxyphenyl) propane, 2,2-bis (4-hydroxypropoxyphenyl) propane), trivalent alcohols (glycerol, 1,1,1-trimethylolethane, 1,1,1-trimethylolpropane, 2,3,4-pentanetriol, 1,2,3-trihydroxybutane, 1,2,6-hexanetriol, tris (2-hydroxyethyl) isocyanurate) and tetravalent to hexavalent alcohols (pentaerythritol, dipentaerythritol, xylitol, arabitol, sorbitol, mannitol). These polyalcohols or derivatives thereof are used singly or in mixtures with one another.

237 082

The synthesis of alkyd resins according to the invention generally involves known one-step and two-step processes. In a one-step production process, the starting reaction components, i.e. the polymeric hydroxyl compound or a mixture thereof with a polyhydric alcohol and a carboxylic acid, are subjected to direct esterification at a temperature of 180 to 250 ° C. The reaction proceeds without or in the presence of a catalyst with the addition of a small amount of azeotropic solvent or in the melt of the reaction mixture and under an inert gas atmosphere. In the two-step process, the initial natural oil is firstly alcoholized, i.e., it is catalyzed by reaction with a polymer hydroxyl compound or a mixture thereof with a polyhydric alcohol at a temperature of 230-2 ° C; The resulting partial esters and excess alcohol are further esterified at the same temperature with a polycarboxylic acid or anhydride thereof. The reaction is again carried out in the presence of an organic solvent or in a melt similar to the previous process. In both cases, the course of the polyesterification is monitored by determining the acid number, measuring the conductivity or viscosity of the reaction mixture.

The alkyd resins obtained in this way are mainly processed as binders for paints. The drying alkyd resins are cured by oxidative polymerization of ester-linked unsaturated acyclic carboxylic acids in the presence of air drying desiccants. The non-drying alkyd resins in combination especially with amino resins are cured by firing at a temperature of 120 to 160 ° C.

The invention is illustrated by the following examples.

Example 1

An alkyd resin having a total ester-linked alcohol content of 72% by weight. polymeric hydroxyl copolyraer of molecular weight 500 and hydroxyl number mg KOH. g -1 prepared by the Priedl-Craft reaction

% 237 082 pentene-hexene-cyclopentadiene-piperylene-indene-butadiene-hydroxyethyl methacrylate; glycerol. This alkyd resin was prepared in a two-step process by subjecting 304 g of linseed oil and 88 g of glycerin to alcoholysis at 240 ° C under an inert atmosphere for 150 minutes with catalysis of 0.045 g of PbO. After cooling to 100 ° C, 228 g of copolymers, 112 g of phthalic anhydride and 28 g of benzoic acid are added to the alcoholysate and azeotropic esterification is carried out at temperatures of 180-250 ° C with addition of 20 ml of xylene until the acid number drops below 10 mg KOH. g ” ¹ . The lacquer is prepared by diluting the obtained alkyd with xylene to a 50% solution having a viscosity of 150 mPa.s at 20 ° C.

Example 2

An alkyd resin in which the total content of ester-linked alcohols is 89% by weight. alcohol prepared by addition of 1.5. wt. % of acrylacrylate per 98.5 wt. % of the copolymers of pentene-hexene-indene-butadiene-cyclopentadiene-piperylene having a molecular weight of 1,500 and 11 wt. pentaerythritol.

In the two-step preparation of the resin, 304 g of sunflower oil with 20 g of glycerol at 240 ° C under an inert atmosphere are first catalysed under catalysis with 0.045 g of LiOH for 150 minutes. After cooling to 100 [deg.] C., 177 g of the copolymer with hydroxyethyl methacrylate, 26 g of isophthalic acid and 2 g of pyromellitic dianhydride are added successively and the azeotropic esterification is carried out at 180-250 [deg.] C. until the acid number falls below 10 mg. ¹ . Dilution of the obtained alkyd with toluene to a 50% solution gives a lacquer with a viscosity of 180 mPa · s at 20 ° C.

Example 3

An alkyd resin having a total ester base content of 237,082 alcohols is 5 wt. polymeric hydroxyl copolymer of molecular weight 1500 prepared by addition of 4 wt. parts by weight of hydroxyethyl acrylate to 96 wt. % by weight of parts of pentene-hexene-indene-butadiene-cyclopentadiene-piperylene copolymers; trimethylolpropane.

To the alcoholysate obtained in the first step from 304 g of safflower oil and 145 g of trimethylolpropane under catalysis of 0.045 g of CaO by heating to 240 ° C for 150 minutes, in the second step, 7.7 g of hydroxyethyl methacrylate copolymer adduct are added at 100 ° C. 5 g of phthalic anhydride, 23 g of p-tert-butylbenzoic acid and azeotropically and azeotropically esterified to an acidity value below 10 dlg KOH.g ^-1 at temperatures of 180 to 240 ° C with the addition of 20 ml of xylene. The alkyd obtained is diluted with xylene to a 50% solution with a viscosity of 200 mPa · s at 20 ° C.

Example 4

An alkyd resin in which the total content of ester-linked alcohols is 74% by weight. alcohol prepared by addition of 3 wt. parts by weight of hydroxyethyl methacrylate to 97 wt. % by weight of parts of pentene-hexene-indene-butadiene-cyclopentadiene-piperylene copolymers having a molecular weight of 4,500; % pentaerythritol and 3 wt. dipentaerythritol.

The one-step process consists of azeotropic esterification of 304 g of soybean oil fatty acids, 41 g of tetrahydrophthalic anhydride and 134 g of hydroxyethyl methacrylate copolymer adduct at temperatures of 180-230 ° C with the addition of 20 ml of xylene in inert medium. ” ¹ . The alkyd obtained is diluted with white spirit to a 50% solution with a viscosity of 180 mPa · s at 20 ° C.

Claims (3)

1. Alkyd resins based on the reaction products of alcohols with carboxylic acids and optionally vegetable oils obtainable from 40 to 65 wt. parts by weight of vegetable oils and / or acyclic carboxylic acids prepared therefrom having carbon numbers of 14 to 36, 20 to 45 wt. % of alcohols containing 1 to 6 hydroxyl groups, at least 1% of which are polymeric alcohols having an average mol. weight 500 to 5000 from the group of copolymers and / or adducts of hydroxyalkyl Λ,? - unsaturated carboxylic kyselil ^ with _y carbon number of 3-6, containing in hydí ^ H ^-voltage groups of 2-4 carbon atoms, and hydrocarbons having 4 to 12 carbon atoms and 1 to 2 double bonds and 1 to 30 wt. % of monocarboxylic to tetracarboxylic acids having 7 to 12 carbon atoms. 2. A process for the preparation of alkyd resins according to claim 1, wherein the mixture of 40 to 65 wt. parts by weight of acyclic carboxylic acids having a carbon number of 14 to 36 prepared from vegetable oils, 20 to 45 wt. parts by weight of alcohols containing 1 to 6 hydroxyl groups and 1 to 30 wt. parts of monocarboxylic to tetracarboxylic acids having a number of carbon atoms of 7 to 12 are reacted at a temperature of 180 to 2 ° C in the presence of transesterification catalysts, organic non-reactive solvents or inert gases, if necessary, until the acid number of the product falls below 10 mg KOH.g ^-1 . 3. A process for the preparation of alkyd resins according to claim 1, characterized in that it is first carried out at a temperature 237 082 220 DEG-250 DEG C. for 120 to 180 minutes alcoholysis of vegetable oils alone with the addition of stoichiometric to all alcohols containing from 1 to 6 hydroxyl groups, followed by the addition of monocarboxylic to tetracarboxylic acids having 7 to 12 carbon atoms, any remaining alcohols and the optionally used acyclic carboxylic acids 14 to 36, prepared from vegetable oils, are reacted at a temperature of 180 to 250 ° C in the presence of a transesterification catalyst _{t of} organic non-reactive solvents or inert gases, if necessary, until the acid number of the product falls below 10 mg KOH. g ” ¹ .