CS233193B1 - Coating compounds based on alkyd resins in air drying - Google Patents

Abstract

Paints consist of alkyd resin, which has, out of the total amount of hydroxyl groups present in the starting reaction components, 10 to 35% of free hydroxyl groups, 6 to 11% of hydroxyl groups bound in reaction with isocyanates and 50 to 85% of hydroxyl groups bound in ester with carboxyl groups. Of the total amount of bound polyhydric alcohols, 15 to 65% by weight are acyclic alcohols and 35 to 85% by weight are polymeric alcohols, which are prepared by radical copolymerization of styrene with esters derived from acrylic or methacrylic acid and acyclic dihydric alcohols, with hydroxyesters derived from these acids and acyclic dihydric alcohols and optionally also with acyclic unsaturated monocarboxylic acids. Coating materials further consist of organic solvents, pigments and/or fillers, drying agents, additives and additional binders.

Description

The invention relates to coating materials with exceptionally fast drying and resistance to overpainting.

Air-drying paints constitute a significant proportion of the total quantity of paints produced. A significant part of them are ^fentuk paints, in which some type of oil alkyd is used as a binder. The properties of the resulting paints are fundamentally influenced by the components used and their mutual ratios.

The great advantage of alkyd paints is their good drying and generally good mechanical properties. However, in some applications, further acceleration of drying is required in order to speed up the handling of the treated objects. This is usually achieved by curing, i.e. by exposing the paint to the object at temperatures of 40 to 70 °C, which, however, requires the installation of equipment and increases energy consumption.

Another problem arises when dried coatings are further overcoated or repainted with coatings containing oxygenated solvents and aromatics. This usually results in surface defects, sometimes even the deterioration of the coatings.

The above-mentioned shortcomings and difficulties are eliminated by the present invention, the subject of which are coatings based on alkyd resins further containing organic solvents and optionally drying agents, fillers, pigments, additives or supplementary binders.

233 193

The essence of the invention is that the coatings consist of 150 to 500 parts by weight of modified alkyd resin, which, out of the total amount of hydroxyl groups present in the starting reaction components, has 10 to 35% of free hydroxyl groups, 6 to 11% of hydroxyl groups bound after reaction with isocyanates, mainly by the -NH-C00- bond, and 50 to 85% of hydroxyl groups bound in an ester manner with carboxyl groups, while out of the total amount of bound polyhydric alcohols, 15 to 65% by weight are acyclic alcohols with 2 to 5 ₇ carbon atoms and 2 to 4 hydroxyl groups and 35 to 85% by weight are polymeric alcohols, prepared by radical copolymerization of 1 mole of styrene with 0.35 to 1.70 moles of esters derived from acrylic or methacrylic acid and acyclic monohydric alcohols with a number of carbon atoms of 1 to 4» with 0.02 to 0.30 moles of hydroxyesters derived from these acids and acyclic dihydric alcohols with a number of carbon atoms of 1 to 4 and optionally up to 0.1 mole of acyclic unsaturated monocarboxylic acids with a number of carbon atoms of 13 to 22 and an iodine number of 120 to 200 g Jg/100 g. Furthermore, they contain 150 to 600 parts by weight of organic solvents from the group including white spirit, xylene, ethyl or butyl acetate, butanol and isobutanol. They may also contain up to 650 parts by weight of pigments and/or fillers and up to 150 parts by weight of parts of drying agents, additives and supplementary binders, especially from the group including alkyds and copolymers containing vinyl and/or acrylate segments.

The coatings of the composition according to the invention are characterized by extremely fast drying in all stages. This allows handling of coated objects after a very short time after application of the coatings. The coatings dry quickly even without the addition of drying agents and have excellent adhesion and good mechanical properties. Coatings made from the base coatings, even without the addition of drying agents, are resistant to solvents during drying and through-drying. This allows them to be overcoated or oversprayed even after

233 193 three-cell coating materials. The topcoats are characterized by good gloss and color retention, especially whiteness.

Alkyd resins used for the preparation of paints are characterized by their composition according to examples A to P given in Table 1. For these alkyds, polymer alcohols prepared by radical polymerization of monomers with the composition given in Table 2 were used. Table 3 summarizes the iodine numbers of vegetable oils and derived acyclic and monocarboxylic acids used for the preparation of alkyd resins.

For the preparation of coatings, well-known types of pigments and anti-corrosive pigments are also used, especially oxides of iron, titanium, lead, as well as lithopone, zinc phosphate, zinc tetraoxychromate, but also special so-called core pigments and color pigments, including organic and others. As fillers, mainly blanc-fix, mining rock, precipitated calcium carbonate, micro-ground limestone, kaolin, dolomite, chalk, quartz fly ash, slate flour, colloidal silicon dioxide, metal powder of copper, zinc, aluminum. As drying agents, salts of naphthenic acids, resin acids or octoates of cobalt, manganese, lead, calcium and other metals are used. To suppress the formation of scale, ketoximes, aldoximes, alkyl- or arylphosphines are added.

Coating materials from the listed components can be prepared on all known types of equipment, especially on ball (pearl) or sand mills.

The coatings dry to level 1 from 10 min. to 15 min. and to level 4 or 5 a maximum of 3 hours. Based on the evaluation results, the coatings according to the invention are particularly suitable for extremely fast-drying primers, but also for base coatings and enamels, used primarily for structures and metal equipment, as well as for coatings of other substrates, especially wood.

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Table 2

233 193

Composition of polymer alcohols prepared by radical polymerization of these monomer mixtures (molar ratios)

Polymer alcohol I II III IV in Monomers: Styrene 1 1 1 1 1 Ethyl acrylate - 0.650 M 0.230 1,060 Butyl acrylate - 0.100 0.036 0.140 0.120 Methyl methacrylate 1,040 0.530 0.380 0.690 0.360 2-hydroxyethyl acrylate — . — 0.020 0.060 - 2-hydroxyethyl methacrylate 0.028 — — - - 2-hydroxypropyl- acrylate — 0.050 — 0.040 0.230 Acids of dehydrated castor oil 0.086 0.003 Linseed oil acids o* 0.046 - - -

Tab. 3 Iodine value of used vegetable oils and corresponding carboxylic acids Component —1 iodine number g Jg.100 g LO 172.9 SO 129.5 KLO 161.4 KSO 124.7 KDRO 127.5

233 193

The meaning of the abbreviations of the components used in Tables 1 and 3 is as follows:

LO linseed oil SO soybean oil KLO linseed oil acid KSO soybean oil acid KDRO acid of dehydrated oil G glycerol P pentaerythritol NPG neopentyl glycol EG ethylene glycol PA phthalic anhydride THPA tetrahydrophthalic anhydride KB benzoic acid Captain BUB p-tertbutylbenzoic acid KA adipic acid PA I and V polymer alcohol I to V TDI 2,4-toluene diisocyanate IPDI i z o f o r ondi i zocyanate 1.6 H.I.D.I. 1,6-hexamethylene diisocyanate

233 193

The subject of the invention is illustrated by examples of coatings for which alkyd resins characterized in Tables 1 to 3 were used. Some properties of coatings made according to the examples are summarized in Table 4. The properties were determined according to the following procedures:

CSN 67 3052 CSN 67 3050 CSN 67 3061 CSN 67 3076

ČSN 67 3079

ČSN 67 3081

ČSN 67 3085

Drying of paints

Preparation of test coatings

Coating thickness measurement

Determination of paint film hardness using a pendulum device

Determination of the bending resistance of a paint film

Determination of paint film resistance by indentation in an Erichsen apparatus Paint adhesion

T a b .4

Some properties of coatings from the coatings listed in examples 1 to 6

Property 1 2 Word 3 law 4 5 6 Drying, level 1, min, ,10 15 13 10 13 10 Drying, level 4» h 2 3 3 2 2 2 Pendulum hardness, % of standard after 10 days 18 22 25 27 18 22 Adhesion, degree A1 A1 A1 A1 A1 A1 Dig resistance, mm 6.7 7.1 7.1 7.5 6.7 7.1 Bending strength, mm 3 3 2 3 2 3

The properties of the coatings were evaluated after 3 days from the date of their preparation.

Example 1 233 193

Primary anti-corrosion paint for metal structures, red, extremely fast drying Total Dry land Solvent Modified Alkyd Resin A 380 190 190 Red iron oxide Micro-ground slate Talc Zinc gallium Aluminum stearate 220 230 80 50 3 Methylethylketoxin Cobalt(II) Taftenate (xylene solution with Co as metal) 3 2 0.3 1.7 Xylene 32

Example 2 Base paint for metal construction gray, very fast drying Total Land Solvent Modified alkyd resin B 400 200 200 Lithopone 280 Zinc white 50 zinc gall 26 Talc 45 Micro-ground slate 147 LTN Carbon Black 2 Xylene 50

Example 3 233 193 Color base white quick drying Total Dryness Rcgpcuš’* tedlo Modified alkyd resin- kyřxoe C 410 205 205 Lithopone 390 Zinc white 40 Ground talc 100 Aluminum stearate 3 Butylaldoxin 3 Xylene 94 Example 4 Synthetic base paint dries very quickly drying, khaki Total Solids Solvent Modified alkyd resins D-cup 380 190 190 Lithopone 180 Zinc white S0 Black iron oxide 5 Ferric oxide yellow 47 Micro-rhein limestone 140 Fixed membrane 120 Manganese naphthenate (2 0 Mn like metal) 8 0.8 7.2 Butylaldoxin 3 Xylene 57

Example 5 233 193

Synthetic topcoat paint, quick-drying for agricultural machinery, green

Total Solids Solvent

Modified Alkyd Resin A 360 180 180 Modified alkyd resin P 240 120 120 Copolymer of vinyl chloride with vinyl acetate 70 18 52 Chrome green 125 Zinc white 135 Cobalt naphthenate 1% Co as metal 3 0.5 2.5 Xylene 67

Example 6 Synthetic enamel very fast drying for industry, white Solvent Total Dry land Modified Alkyd Resin E 688 344 344 Blanc-fixe Titanium white rutile Methylethylketoxin Cobalt naphthenate (xylene, 75 200 3 z z solution with 1% Co j as metal ) 2 0.3 1.7 Xylene 32

Claims (1)

Alkyd resin based paints (further comprising organic solvents and, optionally, desiccants, fillers, pigments, additives or binder additives), characterized in that they consist of 150 parts by weight to 500 parts by weight of an alkyd resin having: of the total amount of hydroxyl groups present in the starting reactants 10 to 35% of hydroxyl groups free, 6 to 11% of hydroxyl groups bound after reaction with isocyanates, in particular -NH-COO-, and 50 to 85% of ester-linked hydroxyl groups with carboxyl groups wherein, of the total amount of polyhydric alcohols bound, 15 to 65% by weight of acyclic alcohols having 2 to 5 carbon atoms and 2 to 4 hydroxyl groups and 35 to 85% by weight of polymeric alcohols are prepared by radical copolymerization of 1 mole of styrene with 0.35 to 1.70 moles of esters derived from acrylic or methacrylic acid and acyclic monovalent and 0.02 to 0.30 moles of hydroxy esters derived from these acids and acyclic divalent alcohols having 1 to 4 carbon atoms and optionally up to 0.10 moles of acyclic unsaturated monocarboxylic acids having carbon numbers atoms 13 to 22 and iodine number 120 to 200 g Jg / 100 g, 150 to 600 wt. parts of organic solvents selected from the group consisting of white spirit, xylene, ethyl acetate, butyl acetate, butanol and isobutanol and optionally up to 650 wt. parts of pigments and / or fillers and up to 150 wt. parts of desiccants, additives and supplementary binders, in particular from the group comprising alkyds and copolymers comprising vinyl and / or acrylate segments.