CS258984B1 - Waterborne alkyd based paints. dispersions - Google Patents

Abstract

The purpose of the solution is to improve the shelf life of coatings based on this base and increase resistance to elevated and lowered temperatures and mechanical stress. This is achieved by a new composition of these materials, which consists of alkyd dispersions containing products of the catalyzed reaction 32 to 60, and aqueous alkyd dispersions with polyisocyanates in a weight ratio of 1 : 0.03 to 0.20, surfactants, siccatives and possibly other components.

Description

The invention relates to water-based coatings based on alkyd dispersions without organic solvents.

A wide range of synthetic polymers, such as epoxies, acrylates and polyesters, are used as binders in the preparation of paints. The most commonly used polymer is alkyd resins, which serve as binders in air-drying and heat-curable paints. Alkyd resins are usually dissolved in organic solvents, such as xylene, white spirit, etc. After the paint is applied, these solvents escape into the atmosphere without any benefit and, moreover, pose a health risk to workers. A major advance has therefore been the preparation of paints from water-dilutable alkyd resins. These are usually resins with a higher acid number (up to 60 mg KOH g~^) or concentrated solutions in oxygen-containing solvents, such as butylene glycol ether. These highly concentrated solutions are then diluted with water in the preparation of paints. Another method consists in converting alkyds into the form of aqueous dispersions. Known methods produce coatings that are either not very stable ₍ or the prepared coatings have high moisture content, a strong tendency to yellow and also have poor mechanical properties.

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The above-mentioned shortcomings and difficulties are largely eliminated by the invention, the subject of which are water-dilutable coatings based on modified alkyd dispersions, surfactants, siccatives and possibly other components from the group including supplementary water, water-dilutable binders of the type of amino resins, vinyl copolymers and other types of alkyds, pigments, fillers, dyes, spreading agents, biocides, defoamers, pH regulators, viscosity regulators, coalescents and corrosion inhibitors. Its essence lies in the fact that they consist of 100 to 550 parts by weight of water-dilutable modified alkyd dispersions, prepared by catalyzed reaction of 32 to 60% aqueous alkyd dispersions with polyisocyanates in a weight ratio of 1 : 0.03 to 0.20, further of 5 to 25 parts by weight of surfactants and 5 to 25 parts by weight of siccatives. «

The coatings prepared according to the present invention are stable for more than 1 year. They withstand, without changing their properties, reduced temperatures up to -10 °C and increased temperatures up to +40 °C. They do not change even after exposure to mechanical stress.

As siccatives, salts of naphthenic, resin acids and octoic acid or octoates of cobalt, manganese, lead, calcium and other metals are used in combination with tetraethoxylated or nonaethoxylated nonylphenols, and also with ammonium salts of sulfated alkylphenolpoly(ethyleneoxy)ethane. It is preferable to use them in the form of an aqueous dispersion.

These coatings can also be prepared by direct dispersion of pigments, especially iron oxide, titanium, lead, anti-corrosive pigments, as well as lithopone, zinc phosphate, zinc tetraoxychromate, etc. As fillers, blanc-fix, precipitated calcium carbonate, micro-ground limestone, kaolin, dolomite, chalk, quartz dust, colloidal silicon dioxide, metal powders, copper, zinc can be used.

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The coatings of the composition according to the invention are best prepared by mixing a siccative into the alkyd dispersion. Pigmented coatings are most easily prepared by further mixing in pigment pastes. The preparation is completed by homogenization with other components as mentioned in the subject of the invention. The pigment pastes are prepared in advance on one of the known devices. It is important that they contain enough suitable surfactants or other substances that will coat their surface. This ensures sufficient stability of the pastes and the resulting coatings.

The coatings according to the invention are stable under normal storage conditions. They can withstand shock temperatures of -10 °C and +40 °C. They are sufficiently stable when diluted with water and under mechanical stress. They can be applied by brush, air gun spraying, dipping, etc. The resulting coatings are well-flowing and dry to stage 1 in 6 and to stage 4 in 1 to 3 days. After drying, the coatings are water-resistant, can be recoated _and have excellent adhesion and good mechanical properties. They are particularly suitable for surface treatment of metal structures.

The subject of the invention is illustrated by examples. The evaluations given in the examples are carried out in accordance with valid Czechoslovak standards;

ČSN 67 3050 Preparation of test coatings

ČSN 67 3052 Drying of coatings

ČSN 67 3061 Measurement of coating thickness

ČSN 67 3076 Determination of paint film hardness using a pendulum device

ČSN 67 3063 Visual assessment of paint gloss

ČSN 67 3079 Determination of the resistance of a paint film to bending ČSN 67 3081 Determination of the resistance of a paint film by indentation in an Erichsen apparatus ČSN 67 3085 Adhesion of paint

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Characteristics of the used alkyd dispersions.

The following alkyd dispersions were used to prepare the coatings in the above examples:

Alkyd dispersion A

Water-dilutable modified alkyd dispersion consisting of 600 parts by weight of the reaction products of aqueous alkyd dispersion A with technical toluene diisocyanate and 400 parts by weight of other components, including 30 parts by weight of sodium salt of N-(1,2-dicarboxyethyl)-N-octadecyl sulfosuccinate, 30 parts by weight of dodecylbenzene polyethylene glycol ether, 20 parts by weight of polyvinyl alcohol, 20 parts by weight of n-butyl ethylene glycol ether, parts by weight of 35% aqueous ammonia solution, 25 parts by weight of copolymers of ethylene oxide with propylene oxide, 20 parts by weight of dimethyllaurylbenzylaminium bromide and 250 parts by weight of additional water.

Alkyd dispersion B

Water-dilutable modified alkyd dispersion consisting of 850 parts by weight of the reaction products of aqueous alkyd dispersion B with 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate and 150 parts by weight of other components, including 10 parts by weight of ethoxylated nonylphenol (4 moles of ethylene oxide per 1 mole of nonylphenol), 20 parts by weight of disodium salt of fatty alcohol half-ester and sulfosuccinic acid, 30 parts by weight of carboxymethylcellulose, 5 parts by weight of triethylamine, parts by weight of ammonium base bis-(tributyltin) oxide and 70 parts by weight of additional water.

Alkyd dispersion C 258 984

Water-dilutable blue-tinted alkyd dispersion consisting of the reaction products of aqueous alkyd dispersion C with a mixture of technical toluene diisocyanate and 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (mass ratio 1 : 1).

Alkyd dispersion D

Water-dilutable modified alkyd dispersion consisting of 550 parts by weight of reaction products of aqueous alkyd dispersion D and 450 parts by weight of other components, including 20 parts by weight of disodium salt of sulfosuccinate half-ester, 30 parts by weight of carboxymethylcellulose and 400 parts by weight of additional demineralized water.

Cobalt naphthenate-based siccative A cobalt naphthenate (Co metal content)

11% by weight) 120 parts by weight ammonium salt of sulfated alkylphenyl poly(ethyleneoxy)ether 150 parts by weight nonaethoxylated nonylphenol 50 parts by weight water (hardness 2 m val . 1 ) 680 parts by weight

Siccative B based on a mixture of cobalt octoate and lead octoate cobalt octoate (Co metal content 10% by weight) lead octoate (Pb metal content 30% by weight) xylene tetraethoxylated nonylphenol

20 mass parts 50 mass parts 425 mass parts 5 mass parts

β

258,984 nonaethoxylated nonylphenol 17 parts by weight ammonium salt of sulfated alkylphenyl poly(ethyleneoxy)ether 10 parts by weight demineralized water 458 parts by weight cobalt octoate (Co metal content 10% by weight) lead octoate (Pb metal content 30% by weight) surfactant C demineralized water

Tenside C had the following composition:

Siccative C based on a mixture of cobalt octoate and lead octoate

100 parts by weight

230 parts by weight 400 parts by weight 320 parts by weight

⁺ where R,j is the decile

R ₂ , R^ 2-hydroxyethyl

R, hydrogen and 10% by weight of a minor component which contains a mixture of aliphatic hydrocarbons with 40% by weight of aromatic hydrocarbons. When determining the distillation curve, 50% by weight of the mixture distilled at 268 °C.

Example 1

Transparent metal varnish Alkyd dispersion A Tenside C

909.1 parts by weight

25.0 wt. parts

10% nitrite solution 10% benzoate solution Siccative dispersion A Sodium butyl glycol in water Sodium in water

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1.0 parts by weight 9.0 parts by weight

25.0 parts by weight 30.0 parts by weight

The method of preparing transparent varnish consists of mixing all ingredients and homogenizing at 500 rpm for 5 minutes.

Features:

Drying to level 1 max o 1 hour to level 2 - max. 4 hours Pendulum Hardness (%} after 10 days min. 10 Dredging resistance (mm) 8 Bending resistance (mm) 10 Grid cut adhesion (old) 1

Example 2

Semi-matt enamel for interior use

Alkyd dispersion B

Dispersion siccative B

Copolymer dispersion of ethyl acrylate in styrene with a content of 1 5% acrylic acid in the polymer - surfactant

0% aqueous solution of sodium hexamethaphosphate 1 0% aqueous solution of sodium nitrite 10% aqueous solution of sodium benzoate Ethylene glycol

Butyl glycol

Titanium white rutile

730.0

25.0

5.0

30.0

1.0

9.0

20.0

20.2

180.0 wt.

mass.

mass.

mass.

mass.

mass.

mass.

mass.

mass.

parts parts parts parts part parts parts parts parts parts

The liquid components are placed in a container with a stirrer and the pigment is gradually added while stirring. The mixture is homogenized and dispersed in a pearl mill. The grinding fineness is below 20 µm. The coating material prepared in this way is filtered through a sieve.

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Features:

Drying to st. 1 (minutes) max 30 to st. 2 (h) max 3 to st. 3 (h) max 24 Gloss (st.) 4 Pendulum hardness FRIDAY 1 0 days (%) minutes 20

Example 3 Base coat Alkyd dispersion C 550.0 parts by weight Dispersion siccative B 5.0 parts by weight 10% aqueous solution of sodium hexamethaphosphate 87.0 parts by weight Tensile C 5.0 parts by weight Propylene glycol 20.0 parts by weight Butyl glycol 18.0 parts by weight 10% aqueous solution of sodium nitrite 1.0 part by weight 10% aqueous solution of sodium benzoate 9.0 parts by weight Titanium white rutile 180.0 parts by weight Blanc-fixe 80.0 parts by weight Talc 80.0 parts by weight Into a container equipped with a stirrer will submit all the components and the mixture is homogenized and dispersed in a pearl mill. Features: Drying to stage 1 max 35 minutes to st. 2 max 1 hour to grade 5 within 24 hours Pendulum hardness after 10 days (%) min 1 0 Dredging resistance (mm) 2 Bending resistance (mm) 10 Grid Cut Adhesion (st.) 1 Gloss (st.) 4

Example 4

Primer

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Alkyd dispersion D Styrene-acrylate dispersion 390.0 parts by weight 150.0 parts by weight Tensile C 15.0 parts by weight Dispersion siccative A 20.0 parts by weight 10% aqueous solution of sodium hexeunethaphosphate 50.0 parts by weight Demineralized water 9.0 parts by weight 1 aqueous solution of sodium nitrite 1.0 part by weight 10% aqueous solution of sodium benzoate 9.0 parts by weight Titanium white rutile 150.0 parts by weight Zinc phosphate 90.0 parts by weight Soot 8.0 parts by weight Talc 70.0 parts by weight Micro-ground mica 30.0 parts by weight

All components except the styrene-acrylate dispersion are placed in a container with a stirrer. The mixture is homogenized and dispersed on a bead mill to a grinding fineness below 20 μm. The styrene-acrylate dispersion is added to the mass thus prepared and the mass is homogenized.

Features:

Drying to the 1st. 1 max 40 minutes to st. 2 max 2 h to st. 5 to 24 h Pendulum hardness after 10 days (%) minutes 15

Resistance to digging (mm) 8 Resistance to bending (mm) 3 Adhesion to cross-cut (st) 1

Example 5

Anti-corrosion coating

Alkyd dispersion A

Styrene acrylate dispersion

Dispersion siccative C

Surfactant C

10% aqueous solution of sodium benzoate 1 0% aqueous solution of sodium nitrite 1 0% aqueous solution of sodium hexamethaphosphate Butyl glycol

Propylene glycol

Zinc phosphate

Blanc-fixe

Talc

Micro-ground mica

Reddish-brown iron oxide

Demineralized water

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100.0 parts by weight 900.0 parts by weight

25.0 parts by weight 25.0 parts by weight 20.0 parts by weight

2.0 parts by weight 190.0 parts by weight 40.0 parts by weight 38.0 parts by weight 180.0 parts by weight 195.0 parts by weight 96.0 parts by weight 140.0 parts by weight 210.0 parts by weight 900.0 parts by weight

The liquid components are placed in the mixer container and pigments and fillers are gradually added while stirring. The mixture is homogenized and dispersed on a pearl mill to a grinding fineness of 20 /um. Prepared coating material with a filter closureProperties:

Drying to stage 1 max 30 minutes to st. 2 max 3 hours to st. 4 within 24 hours Pendulum hardness after 10 days (%) min 30 Dredging resistance (mm) 4 Bending resistance (mm) 8 Grid Cut Adhesion (st.) 1

Example 6

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Quick-drying paint for chipboard

Alkyd dispersion A

Styrene-acrylate dispersion Dispersion siccative C Surfactant C

0% aqueous solution NaHMP Iron oxide reddish brown Blanc-fixe

Talc

Micro-ground mica

Demineralized water

Butyl glycol

Propylene glycol

550.0

825.0

25.0

25.0

240.0

502.0

155.0

130.0

189^0

854.0

54.0 51.0 wt.

mass.

mass.

mass.

mass.

mass.

mass.

mass.

mass.

mass.

mass.

mass.

parts parts parts parts parts parts parts parts parts parts parts parts

The liquid components are placed in the mixer container and pigments and fillers are gradually added while stirring. The mixture is then homogenized and dispersed in a pearl mill. The prepared coating material is finally filtered through a sieve.

Features:

Drying to stage 1 max 40 minutes to st. 2 max 4 h to st. 4 to 30 h Pendulum hardness after 10 days (%) minutes 30 Dredging resistance (mm) 6 Bending resistance (mm) 8 Cross-section adhesion (st) 1

Claims (1)

Water-based paints based on alkyd dispersions, surfactants, desiccants and possibly other ingredients from the group consisting of make-up water, water-borne binder-type amino resins, vinyl copolymers and other types of alkyds, pigments, fillers, dyes, flow agents, biocides, defoamers, pH regulators viscosity regulators, coalescents and corrosion inhibitors, characterized in that they consist of 100 to 500 parts by weight of water-dilutable modified alkyd dispersions prepared by catalyzing the reaction of 32 to 60% aqueous alkyd dispersions with polyisocyanates in a weight ratio of 1: 0.03 to 0, 20, 5 to 25 parts by weight of surfactants and 5 to 25 parts by weight of desiccants.