EP0321502A1

EP0321502A1 - Air-drying alkyd resin binder, process for its production, coating agent based thereon and its use as house paint

Info

Publication number: EP0321502A1
Application number: EP19870906662
Authority: EP
Inventors: Jörg Pronobis; Vijay Kadambande; Bodo Weber; Rolf Peter-Pollmann
Original assignee: BASF Lacke und Farben AG
Current assignee: BASF Farben und Fasern AG
Priority date: 1986-10-30
Filing date: 1987-10-09
Publication date: 1989-06-28
Also published as: WO1988003153A1; EP0265746A1; DE3636929A1; BR8707847A

Abstract

On obtient des liants en résine alkyde séchant à l'air à partir de: a) entre 40 et 80 % en poids d'acides gras siccatifs et/ou semi-siccatifs, b) entre 15 et 35 % en poids de diols et/ou polyols, au moins 80 % en poids de ces alcools étant composé de di-pentaérythrite et/ou de di-triméthylolpropane, c) entre 5 et 30 % en poids d'acides dicarboniques et/ou polycarboniques, ou leurs anhydrides, d) entre 0 et 10 % en poids de diisocyanates et e) entre 0 et 20 % en poids d'acides monocarboniques, la somme des constituants a), b), c), d) et e) étant égale à 100 % en poids. L'invention concerne également un procédé de production de ce liant en résine alkyde et d'un enduit à base des résines alkydes décrites. L'enduit a une teneur en matière solide d'au moins 75 % en poids et peut être avantageusement appliqué comme peinture bâtiment séchant à l'air.Binders of air-drying alkyd resin are obtained from: a) between 40 and 80% by weight of siccative and / or semi-siccative fatty acids, b) between 15 and 35% by weight of diols and / or polyols, at least 80% by weight of these alcohols being composed of di-pentaerythritis and / or of di-trimethylolpropane, c) between 5 and 30% by weight of dicarbonic and / or polycarbonic acids, or their anhydrides, d) between 0 and 10% by weight of diisocyanates and e) between 0 and 20% by weight of monocarbonic acids, the sum of the constituents a), b), c), d) and e) being equal to 100% by weight. The invention also relates to a process for producing this binder in alkyd resin and a coating based on the alkyd resins described. The coating has a solid content of at least 75% by weight and can be advantageously applied as an air-drying building paint.

Description

Air-drying alkyd resin binders, processes for their preparation, coating compositions based on the alkyd resin binders and their use as architectural paints

The present invention relates to air-drying alkyd resin binders produced from drying and / or semi-drying fatty acids, di- and / or polyols, part of the alcohols being replaced by di-trimethylolpropane and / or di-pentaerythritol, and di- and / or polycarboxylic acids.

Building paints belonging to the prior art are based on air-drying alkyd resins which are formed from drying and / or semi-drying, vegetable or animal oils or fatty acids. Pentaerythritol, trimethylolpropane and glycerol, for example, are used as the alcohol component. Diols can also be used in part. Aromatic dicarboxylic acids are preferably used as the acid component. These binders are used to obtain paints with solids contents of up to about 70% by weight with an application viscosity. The most suitable solvents are gasolines with an aliphatic fraction from 140 ° C to 200 ° C. Known varnishes of this type have good processing and drying properties, good weather resistance and good properties with regard to the gloss. However, it is disadvantageous that these systems contain a solvent content of at least 30% by weight.

In order to reduce the content of organic solvents, aqueous alkyd resin systems have been developed. Paints based on water-soluble alkyd resins require up to 20% by weight of volatile organic solvents in order to be easy to process.

When aqueous dispersions are used, the disadvantage arises that the resulting coatings are not shiny and are not sufficiently resistant to blocking.

It is known to produce so-called high-solid lacquers by lowering the molecular weight of the binders and by using thixotropic agents. In this way, air-drying alkyd resins with high solids content produced in this way have the disadvantage that these systems dry very poorly.

The dimer of trimethylolpropane, di-trimethylolpropane, an alcohol with 4 primary hydroxyl groups, is recommended for use in air-drying alkyd resins and saturated polyester resins, whereby di-trimethylolpropane is intended to replace part of the polyol content. In the case of the alkyd resins belonging to the prior art, which contain condensed di-trimethylolpropane, however, this polyhydric alcohol only represents up to about a third of the total polyol content. The modification with di-trimethylolpropane leads to an increased flexibility of the resulting coatings without influencing the degree of hardness .

The solids contents of the known alkyd resins modified with di-trimethylolpropane are below 70% by weight with an application viscosity.

The dimer of pentaerythritol, di-pentaerythritol, an alcohol with 6 primary hydroxyl groups, is recommended as a raw material for alkyd resins for coating agents and printing inks.

The object of the present invention was to provide binders which can be air-dried coating compositions with a solids content of Have at least 70% by weight processed at application viscosity. The resulting coating agents should have good drying properties with sufficiently high layer thicknesses.

This object is surprisingly achieved by air-drying alkyd resin binders of the type mentioned at the outset, which are characterized in that the alkyd resins are obtainable from

a) 40 to 80% by weight of drying and / or semi-drying fatty acids,

b) 15 to 35 wt .-% di- and / or polyols, at least 80 wt .-% of the alcohols from di-pentaerythritol and / or

Exist di-trimethylolpropane,

c) 5 to 30% by weight of di- and / or polycarboxylic acids or their anhydrides,

d) 0 to 10 wt .-% diisocyanates and

e) 0 to 20% by weight of monocarboxylic acids,

the sum of components a), b), c), d) and e) being 100% by weight.

Di-trimethylolpropane or di-pentaerythritol are to be understood as the dimers of trimethylolpropane or pentaerythritol which are linked to one another via two hydroxyl groups by an ether group.

The use of di-pentaerythritol and / or di-trimethylolpropane in the above quantitative ratio surprisingly leads to low-viscosity binders which have a very good solubility in white spirit, although the alkyd resins have relatively high molecular weights. There the binders according to the invention are of low viscosity, they can be processed into coating compositions with a solids content of at least 70% by weight with an application viscosity. The incorporation of di-pentaerythritol and / or di-trimethylolpropane in a certain quantitative ratio ensures that a relatively high proportion of fatty acids is incorporated, which leads to the good properties described.

It was surprising that the alkyd resin binders are low viscosity despite the relatively high average molecular weights. The viscosities of the 80% solutions of the binders according to the invention in xylene are in the range from 2.0 to 12.0 dPa.s. 80% strength solutions of the alkyd resin binders in white spirit have viscosities in the range from 2.0 to 10.0 dPa.s at 20 ° C.

The alkyd resins generally have acid numbers from about 2 to 20 mg KOH / g and hydroxyl numbers from about 2 to 100 mg KOH / g.

It is particularly preferred if the alcohol component b) consists of more than 95% by weight of di-pentaerythritol and / or di-trimethylolpropane. 50 to 80% by weight of drying and / or semi-drying fatty acids are advantageously used as component a).

Suitable drying and / or semi-drying fatty acids, which generally have 6 to 24 carbon atoms per molecule, are soybean oil fatty acid, safflower oil fatty acid, sunflower oil fatty acid, cottonseed oil fatty acid, castor oil fatty acid, tall oil fatty acid and linseed oil fatty acid. Naturally, non-drying fatty acids, such as coconut oil fatty acid, isononanoic acid and alpha-ethylhexanoic acid, can also be used in part. In addition to di-pentaerythritol and di-trimethylolpropane, trimethylolpropane, glycerin, ethylene glycol, neopentyl glycol, propylene glycol, 1,6-hexanediol, trimethylolethane, 1,4-dimethylolcyclohexane, 1,3-dimethylolcyclohexane, 1,2-cyclohexanediol and 1 , 4-cyclohexanediol in question.

Suitable di- and polycarboxylic acids are, for example, orthophthalic acid, terephthalic acid, trimellitic acid, tetrahydrophthalic acid, hexahydrophthalic acid, dimer fatty acids, adipic acid and azelaic acid.

Possibly. can also contain up to 10% by weight of diisocyanates, e.g. 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate and hexamethylene-1,6-diisocyanate can also be used. The use of diisocyanates leads to the formation of urethane alkyds.

Suitable monocarboxylic acids (component e) are, for example, benzoic acid, para-tertiary butylbenzoic acid, abietic acid, pivalic acid, lauric acid, stearic acid, cyclopentane carboxylic acid and cyclohexane carboxylic acid. The monocarboxylic acids can be used in a proportion of up to 20% by weight, based on the total weight of the alkyd resin building blocks.

Surprisingly, it was found that with a comparable molecular weight, the higher the fatty acid content in the alkyd resin binder, the lower the viscosity of the binders.

The invention also relates to a method for producing the binders according to the invention, which is characterized in that

a) 40 to 80% by weight of drying and / or semi-drying fatty acids, b) 15 to 35% by weight of diols and / or polyols, at least 80% by weight of the alcohols consisting of di-penthaerythritol and / or di-trimethylolpropane,

c) 5 to 30% by weight of di- and / or polycarboxylic acids or their anhydrides and

e) O to 20% by weight of monocarboxylic acids

are reacted with one another in the melt or in organic solvent at temperatures of 200 ° C. to 260 ° C., organic solvent is optionally added, and if appropriate the reaction is then carried out at 60 ° C. to 140 ° C. with up to 10% by weight of diisocyanates (d), where the sum of components a), b), c), d) and e) is 100% by weight.

The alkyd resin formation takes place on the way of a polyesterification reaction well known to the person skilled in the art. In the addition reaction with diisocyanates, a catalyst for the formation of urethane can optionally be used. A particularly suitable catalyst for polyurethane formation is dibutyltin dilaurate.

Advantageously, in the process according to the invention the alcohol component b) consists of more than 95% by weight of di-pentaerythritol and / or di-trimethylolpropane. 60 to 80% by weight of drying and / or semi-drying fatty acids are particularly advantageously used as component a).

The invention further relates to coating compositions with a solids content of at least 75% by weight, which contain the air-drying alkyd resins according to the invention described above as essential binders and, if appropriate, organic solvents, pigments, fillers, auxiliaries and dry matter Contain substances. By using the alkyd resin binders according to the invention, it is possible to produce coating compositions with a high solids content, so-called "high-solid lacquers", with application viscosity. The binders according to the invention lead to a lowering of the viscosity in comparison to known alkyd resin binders. The coating compositions according to the invention advantageously have a solids content in the range from 85 to 100% by weight. It is therefore also possible with the aid of the air-drying alkyd resins according to the invention to produce easily spreadable coating agents without solvents.

The coating compositions according to the invention can optionally contain pigments, fillers, auxiliaries and drying agents. Pigments include both natural and synthetic, transparent and non-transparent pigments.

Examples of suitable drying agents are metal salts (cyclo) -alliphatic, natural or synthetic acids, e.g. Linoleic acid, naphthenic acid and 2-ethylhexanoic acid, suitable metals being cobalt, manganese, lead, zirconium, calcium and zinc. Of course, mixtures of desiccants can also be used.

Based on the metal content, the dry substances are used in a proportion of 10 ^-3 to about 3% by weight, based on the solid binder.

The invention also relates to a process for the preparation of the coating compositions according to the invention, in which the alkyd resin binders prepared according to the invention and, if appropriate, organic solvents and pigments, fillers, auxiliaries and drying agents are processed into a coating composition by mixing and, if appropriate, dispersing.

The coating compositions according to the invention are particularly suitable for use as architectural coatings. They can be applied in sufficiently thick layers and have good drying properties. The film formation of the coating agents is essentially based on an oxidative drying. The invention is explained in more detail below on the basis of exemplary embodiments. Parts mean parts by weight unless otherwise stated. The following exemplary embodiments are carried out in a reactor which has an agitator, a nitrogen feed line and a separation receiver which separates the azeotropic mixture of aromatics and water via a cooler. The reactor can be heated electrically, inductively or by thermal oil. The temperature is controlled by a thermometer that regulates the temperature of the work piece. The components for the production of alkyd resins are weighed into the reactor. The removal of water takes place with the aid of entraining agents.

Example 1:

An alkyd resin is produced from 753 parts of fatty acid, which is available under the brand name Juvandol, 195 parts of di-pentaerythritol and 114 parts of phthalic anhydride. The key figures are given below:

Fatty acid content: 75%

Acid number: 4 mg KOH / g

Hydroxyl number: 26 mg KOH / g

Solids content: 85%, dissolved in white spirit

Viscosity (80% in white spirit): 10 dPa.s

Molecular weight: 13,000

Example 2:

An air-drying alkyd resin is prepared from 691 parts of a drying fatty acid, 33 g of para-tertiary-butylbenzoic acid, 185 parts of di-pentaerythritol, 61 parts of isophthalic acid, 32 parts of phthalic anhydride, 32 parts of isophorone diisocyanate and 29 parts of a ketone resin.

Key figures:

Fatty acid content: 69%

Acid number: 9 mg KOH / g

Hydroxyl number: 19 mg KOH / g

Solids content: 85% by weight in white spirit

Viscosity (80% in white spirit / xylene in a ratio of 38: 7):

7 dPa.s Comparative Example 1:

An alkyd resin is prepared from 683 parts of a fatty acid available on the market under the brand name Juvandol fatty acid, 184 parts of pentaerythritol and 201 parts of phthalic anhydride.

Fatty acid content: 68% by weight Acid number: 8 mg KOH / g Hydroxyl number: 1.6 mg KOH / g

Solids content: 65%, dissolved in white spirit Viscosity (65% in white spirit): 8.5 dPa.s Molecular weight: 22,220

Example 3:

An alkyd resin is prepared from 783 parts of a semi-drying fatty acid, 177 parts of di-pentaerythritol and 103 parts of phthalic anhydride.

Fatty acid content: 78% by weight

Hydroxyl number: below 2 mg KOH / g

Acid number: below 2 mg KOH / g

Solids content: 100% by weight viscosity (80% in white spirit): 2.4 dPa.s

Molecular weight: 14,300

Comparative Example 2 (Medium Oil Alkyd Resin):

A medium-oil alkyd resin is prepared from 496 g of a fatty acid which is available under the brand name Juvandol fatty acid, 229 parts of pentaerythritol, 80 parts of benzoic acid and 272 parts of phthalic anhydride.

Fatty acid content: 50% by weight acid number: 10 mg KOH / g hydroxyl number: 20 mg KOH / g Solids content: 50% by weight in white spirit and xylene viscosity (50% in xylene): 4.5 dPa.s molecular weight: 88 700

Example 4:

An alkyd resin is prepared from 416 parts of a drying fatty acid, 353 parts of di-trimethylolpropane, 66 parts of benzoic acid and 229 parts of phthalic anhydride.

Fatty acid content: 42% by weight Acid number: 8 mg KOH / g Hydroxyl number: 29 mg KOH / g

Solids content: 80% by weight in white spirit and xylene viscosity (50% in xylene): 1.7 dPa.s molecular weight: 6,460

Example 5:

An alkyd resin binder is prepared from 595 parts of a drying fatty acid, 243 parts of di-pentaerythritol, 95 parts of benzoic acid and 157 parts of phthalic anhydride.

Fatty acid content: 60% by weight

Acid number: 7 mg KOH / g

Hydroxyl number: 43 mg KOH / g

Solids content: 70% by weight in = white spirit

Viscosity (70% in test gasoline): 4 dPa.s molecular weight: 8,000

Examples of use of the alkyd resin binders according to the invention are given below. Lacquer formulations are given for the alkyd resins prepared in Examples 2, 3 and 4. In each case, a comparison is made with a known soy alkyd resin which has been prepared without the use of di-pentaerythritol or di-trimethylolpropane (as the alcohol component pentaerythritol). Comparative Example Example a)

50 T. soy alkyd resin 69 T. alkyd resin (65%) from Example 2, 85%

Bentone paste (10%) 1.5 T. 1.5 T.

CA octoate (6%) 1.0 T. 1.0 T.

TiO ₂ .26.0 T. 25.0 T.

Soy Lecithin 0.3 T. 0.3 T.

Stand oil 5.0 T. -

Ba-Octoat (6%) 2.0 T. 1.0 T.

Co-octoate (6%) 1.0 T. 1.0 T.

Zr octoate (6%) 1.0 T. -

Skin contraceptive 0.5 T. 0.5 T.

Silicone oil 0.5 T. 0.5 T.

White spirit 1.2 T. 0.2 T.

Solids content 65% 85%

Comparative example example b)

50.0 T. Soy alkyd 53, O T. alkyd resin resin (45%) from Example 3 (85%)

Bentone paste (10%) 0.5 T. 0.5 T.

Soy lecithin 0.3 T. 0.3 T.

Ca naphthenate (6%) 1.0 T. 1.0 T.

TiO ₂ 25.0 T. 25.0 T.

Matting paste (20%) 15, no T. 17.5 T.

Zr-Octoat 2.5 T. -

Co-Octoat 1.0 T. 1.0 T ^' .

Skin contraceptive 0.5 T. 0.5 T.

Silicone oil 0.5 T. 0.5 T.

White spirit 3.7 T. 0.7 T.

Solids content 51% 74% Comparative example example c)

45.0 T. of a 45.0 T. of

45% alkyd resin

Juvandolalkydharzes Ex.4 (85%)

Bentone paste (10%) 3.0 T. 3.0 T.

Ca naphthenate (6%) 1.0 T. 1.0 T.

Titanium oxide 11.0 T. 11.0 T.

Chalk 10.0 T. 10.0 T.

Kaolin 14.0 T. 14.0 T.

Talc 12.0 T. 12.0 T.

Co-octoate (6%) 1.0 T. 1.0 T.

Skin contraceptive 1.0 T. 1.0 T.

White spirit 2.0 T. 2.0 T.

Solids content 68% 85 96

The paints produced in Examples a), b) and c) were compared in terms of their drying properties with the paints from the comparative examples. It was found that with the same wet application layer thickness, freedom from dust was achieved after 2 hours (examples) or 1.5 hours (comparative examples). Non-tackiness was achieved after 3.5 hours (examples) and 2.0 hours (comparative examples). The drying through in the examples and the comparative examples was in each case OK after 10 hours.

Claims

Claims:

1. Air-drying alkyd resin binders, produced from drying and / or semi-drying fatty acids, di- and / or polyols, part of the alcohols being replaced by di-trimethylolpropane and / or di-pentaerythritol, and di- and / or polycarboxylic acids, characterized in that that the alkyd resins are available from

a) 40 to 80% by weight of drying and / or semi-drying fatty acids,

b) 15 to 35% by weight of di- and / or polyols, at least 80% by weight of the alcohols consisting of di-pentaerythritol and / or di-trimethylolpropane,

c) 5 to 30% by weight of di- and / or polycarboxylic acids or their anhydrides,

d) 0 to 10% by weight of diisocyanates and

e) 0 to 20% by weight of monocarboxylic acids,

the sum of components a), b), c), d) and e) being 100% by weight.

2. alkyd resin binder according to claim 1, characterized in that the alcohol component b) consists of more than 95 wt .-% of di-pentaerythritol and / or di-trimethylolpropane.

3. alkyd resin binder according to claim 1 and 2, characterized in that 60 to 80% by weight of drying and / or semi-drying fatty acids are used as component a).

4. Process for the production of air-drying alkyd resin binders, produced from drying and / or semi-drying fatty acids, di- and / or polyols, part of the alcohols being replaced by di-trimethylolpropane and / or di-pentaerythritol, and di- and / or polycarboxylic acids, characterized in that

a) 40 to 80% by weight of drying and / or semi-drying fatty acids,

b) 15 to 35% by weight of diols and / or polyols, at least 80% by weight of the alcohols consisting of di-pentaerythritol and / or di-trimethylolpropane,

c) 5 to 30% by weight of di- and / or polycarboxylic acids or their anhydrides and optionally

e) up to 20% by weight of monocarboxylic acids

are reacted with one another in the melt or in organic solvent at temperatures from 200 ° C. to 260 ° C., organic solvent is optionally added and, if appropriate, the reaction with up to 10% by weight diisocyanates is then carried out at 60 ° C. to 140 ° C. (d) , the sum of components a), b), c), d) and e) being 100% by weight.

5. The method according to claim 4, characterized in that the alcohol component b) consists of more than 95% by weight of di-pentaerythritol and / or di-trimethylolpropane.

6. The method according to claim 4 and 5, characterized in that 60 to 80 wt.% Drying and / or semi-drying fatty acids are used as component a).

7. Coating agents with a solids content of at least 75% by weight, containing as essential binder the alkyd resin binder according to Claims 1 to 3 and, if appropriate, organic solvent and pigments, fillers, auxiliaries and drying agents.

8. Coating agent according to claim 7, characterized in that it has a solids content in the range from 85 to 100% by weight.

9. A process for the preparation of a coating composition with a solids content of at least 75% by weight, the alkyd resin binder prepared by the process according to claims 4 to 6 and, if appropriate, organic solvent, and also pigments, fillers, auxiliaries and dryers, being mixed by mixing and optionally dispersing a coating mass can be processed.

10. Warping of the coating agent according to claim 7 and 8 as an air-drying architectural paint.