CS202618B1 - Air drying painting composition - Google Patents

Description

The invention relates to a novel air-drying coating composition comprising pigments, fillers, driers and alkyd resins with improved water and alkali resistance.

Air drying coatings are very popular and widely used. In addition to pigments, fillers, siccatives and other substances, the most important component is a binder, which is one of the known types of glycerine or glycerine pentaphthal (alkyd) resins modified with drying or semi-drying fatty oils or fatty acids.

At present, a number of modified alkyd resins are known, used as binders of paints for indoor and outdoor applications, as well as for the production of primer layers and top enamels. However, none of the known types of modified alkyds fully satisfy all requirements and it is therefore necessary to prepare special types suitable for the application. One of the most demanding applications is primer, which must have the shortest drying and drying time, good film-forming properties, low permeability to water vapor, good adhesion to the substrate, sufficient cohesiveness and strength of the film, very good anticorrosive properties, good overcoatability and especially good resistance to exposure to water and alkaline substances. At present, a modified alkyd resin binder which meets the requirements is not known.

202 618

202 ⁸¹⁸

We have now found a new air-drying coating that satisfies the above requirements to a sufficient degree. The coating composition according to the invention consists of 20 to 35 wt. parts of a drying binder which can be prepared by reacting 6.5 to 8.0 wt. parts of rosin, 4.2 to 4.7 wt. % phthalic anhydride, 2.6 to 5.3 wt. % of phenolic resol and 19 to 21 wt. parts of the equilibrium mixture of partial fatty acid esters of linseed oil with glycerine and pentaerythrite, formed by alcoholysis of linseed oil with pentaerythrite in a molar ratio of fatty acid triglycerides to pentaerythrite of 0.77 to 0.80: 1, up to 20 wt. parts of fillers, up to 50 wt. parts of pigments, up to 30 wt. parts of volatile solvents such as white spirit and / or xylene,

0.01 to 1.0 wt. parts of desiccating compounds, in particular cobalt, manganese, lead and calcium salts of organic acids, and

0.0001 to 0.1 wt. parts of substances, such as loatimes, aldoximes or alkyd or aryl phosphine derivatives, to prevent skin formation.

The alkyd binder for the coating compositions of the present invention is prepared from linseed oil alcohol and pentaerythritol, which is mixed with rosin and phenolic resol. The mixture is allowed to react at a temperature of up to 205 ° C, followed by polyethererification with the addition of phthalic anhydride. The reaction of the components is carried out in the melt in the presence of inert gases or azeotropically in the presence of 1 to 5 wt. % hydrocarbons, in particular xylene or ethylbenzene. Polyesterification is conducted so that the acid number is less than 15 mg KOH / g and the consistency is between 50-200 s / 20 ° C / Ford, 4 mm (60% xylene solution). The modified alkyd resin is then diluted with white spirit or xylene, or mixtures thereof, to 50 to 70% of the solutions used to produce the coating compositions. The rosin used has an acid number of 150 to 170 mg KOH / g, a saponification number of 164 to 210 mg KOH / g and a softening point of at least 50 ° C. Phenolic resol contains 10 to 20 wt. and is prepared by the reaction of phenol and formaldehyde in the presence of alkali or zinc oxide, ZnO, the molar ratio of phenol to formaldehyde being between 0.588 and 0.833 ·

Known types of pigments and anticorrosive pigments, in particular iron oxides, lithopone, blancfix, titanium dioxide, zinc phosphate, zincotetraoxychromate, lead, suboxide lead, alkaline earth chromenes and others are used in the preparation of the coating compositions according to the invention. Fillers are most often finely ground kaolins, slip, chalk, quartz, metal dust and the like. As a desiccant, metal aols derived from naphthenic acids, octoic acid, rosin and the like are used. The metal ion in said salts is cobalt, lead, calcium, manganese, zinc or alkaline earth. Usually a mixture of desiccants is used, containing both the own oxygen transfer agents (Co, Mn, Fe), accelerating film drying, and other salts affecting a number of parameters such as flow, carrier activity, tolerance, wrinkling and the like (Zn, Ca, Ba) , Pb). Small amounts of compounds with a strong affinity for peroxide groups, such as catoximes, aldoximes, or alkyd or aryl phosphine derivatives, are used to control skin formation. These substances act only in closed containers

202 618 whereas in the applied film, the paints are rapidly deactivated by air and do not prevent drying. The finishing of the paint is carried out as required to the desired consistency using white spirit, aromatics or other volatile solvents or mixtures thereof. After application, the coating film dries to Stage A within 3 hours at most and reaches Stage within 10 hours at room temperature. Dried coatings are resistant to water and 5% sodium carbonate solution for 48 hours at room temperature. They can withstand overcoating without defects, have very good adhesion and good hardness.

According to the test results, the coatings according to the invention are particularly suitable as quick-drying primer for structures and metal equipment exposed to intense atmospheric corrosion.

Example 1

Alcoholysis is carried out on a mixture of 165 g of linseed oil and 344 g of pentaerythrite, catalysing 1 g of PbO.200 g of this mixture with 265 g of phenolic resol containing

19.9 wt. % of the groups -CHgOH, 760 g of rosin having an acid number of 165 mg KOH / g and 452 g of phthalic anhydride. The esterification is carried out in the presence of 2 to 3% xylene with simultaneous azeotropic distillation of the reaction water. The alkyd resin thus prepared has an acid number of 8.8 mg KOH / g and the consistency of a 60% solution is 72 s / 20 ° C / Ford, 4 mm. The resin is diluted with white spirit to a 60% solution.

The coating composition is prepared by first siccating the alkyd solution by adding 2.0 g of a 4% calcium naphthenate solution, 0.60 g of a 2% cobalt naphthenate solution, 1.5 g of a 20% lead naphthenate solution, and 0.70 g of a 10% solution manganese naphthenate. 0.20 g of exkine (cyclohexanone oxime) was added to the homogeneous mixture. 9 g of kaolin, 20 g of lithopone (30% ZnS), 10 g of zincktetraoxyhromate, 3 g of iron oxide (FEPHEN), 3 g of micronized slip and 5 g of silica fume are added successively. The mixture was rubbed and homogenized on a mortar and filtered for 60 minutes. Drying of the film to the stage

And ............ 1.5 hours

............3 hours

B _c ............ 7 hours.

The paint on the glass was re-painted after 24 hours of drying, no change occurred, lifting of the paint is not observable. After 72 hours of drying, the coating film has a pendulum hardness

18.9% (based on glass), grip 1, film thickness 40 µm.

Example 2

An alcoholysis of 1700 g of linseed oil and 200 g of pentaerythrite is carried out, catalysing 1.0 g of lead oxide, PbO. 760 g of acid rosin are added to the alcohol

163.1 mg KOH / g, 424 g phenolic resol containing 13.1% -CHgCH groups and then 460 g phthalic anhydride. After esterification, an alkyd resin with a consistency of 60% is obtained

202 018 xylene solution 98 sec / 20 ° C / Eord, 4 ma and acid number 10.9 mg KOH / g. The alkyd resin is diluted with a mixture of white spirit and xylene in wt. ratio of 2: 1 to 65% solution.

g of an alkyd resin solution was treated with 0.80 g of a 2% cobalt octoate solution, 1.9 g of a 15% lead resinate solution, 2.0 g of a 5% calcium naphthenate solution, and 1.0 g of a 10% manganese resinate solution. 0.20 g of exkine is added to the homogeneous mixture. A paint composition was prepared from such a slaked paint by mixing and spreading a mixture consisting of 1 g micronized slip, 14 g blanofix, 20 g zincfoephate, 9 g iron oxide and 7 g titanium dioxide. Drying of the film to the stage

And ............ 1.2 hours

B ^ ............ 2.5 hours

............7 hours.

The paint on the glass after 24 hours of drying can withstand overcoating without noticeable changes.

After 72 hours of drying, the pendulum hardness is 20.1% (based on glass), the adhesion through the grid 1 and the film thickness 45 yam. The sheet coating after 72 hours of drying was immersed in tap water and 5% sodium carbonate solution. There was no observable change after 48 hours.

Example 3

The alkyd resin prepared according to Example 1 was diluted with xylene to a 50% solution.

Add 0.15 g of exkine. 20 g of micronized kaolin, 29 g of micronized zincfoefate, 5 g of titanium dioxide and 5 g of blanofix are added to the solution so treated. The mixture is mixed and thoroughly spread for 120 minutes. The paint dries to the stage in the film

And ............ 1 hour

B ^ ............ 6.5 hours.

After 24 hours of drying, the paint on the glass was overcoated and remained unchanged. After 72 hours of drying, the coating has a pendulum hardness of 19.1% (based on glass), grip adhesion 1, and a film thickness of 40 µm. After 72 hours of drying, the plate coating was immersed for 48 hours in tap water and 5% NagCOp solution without apparent changes.

SUBJECT OF THE INVENTION

Claims (1)

SUBJECT OF THE INVENTION Air-drying paint based on drying agents, solvents, fillers and pigments, characterized in that it consists of: 20 to 35 wt. parts by weight of a binder which can be prepared by reacting with each other 6.5 to 8.0 wt. parts of rosin, 4.2 to 4.7 wt. % phthalic anhydride, 2.6 to 5.3 wt. 202 61 parts of phenolic resol and 19 to 21 wt. parts of an equilibrium mixture of partial fatty acid esters of linseed oil with glycerine and pentaerythrite, formed by alcoholysis of linseed oil with pentaerythrite in a molar ratio of fatty acid triglycerides to pentaerythrite of 0.77 to 0.80: 1, 1 to 20 wt. parts of fillers, 30 to 50 wt. parts of pigments, 15 to 30 wt. parts of volatile solvents such as white spirit and / or xylene, 0.01 to 1.0 wt. parts of desiccating compounds, in particular cobalt, manganese, lead and calcium salts of organic acids, and 0.0001 to 0.1 wt. parts of substances, such as ketoximes, aldoximes, or alkyl or aryl phosphine derivatives, to prevent the formation of the crust.