CS245608B1 - Polyester binding agent and method of its preparation - Google Patents

Abstract

Polyester binder, especially for pigment pastes containing 18 to 30% by weight ester-bound polyalcohol residues with 2 to 4 hydroxyl groups and 70 to 82% by weight of ester-linked acyclic and aromatic monocarboxylic radicals and dicarboxylic acids having 7 to 22 carbon atoms, wherein the monocarboxylic molar ratio and dicarboxylic acids is 1: 0.1 to <0.25. A method of making this the binder is that the triglycerides are acyclic monocarboxylic acids first subjected to catalyzed alcoholysis by polyalcohols and the resulting intermediates are then esterified monocarboxylic and dicarboxylic acids or their anhydrides. Reactions ongoing at 160 to 260 ° C in inert or in the presence of an azeotropic solvent and distilling off by-product reaction products, will cease after a decline acid numbers of the product below 20 mg KOH / g.

Description

The invention relates to polyester binder pigment pastes, coatings, printing and marking inks.

Synthetic binders in the modern paint and ink industry must meet a number of demanding requirements. In particular, it needs to be compatible and miscible over a wide range and choice of the various macromolecular substances with which they are combined.

In addition, they must be well soluble in the additives used, such as organic solvents, plasticizers, elasticizers and other additives. These requirements very well meets the binder component prepared according to MS. No. 244 608.

The present invention provides a mixture of monomeric esters of polyalcohols with monocarboxylic acyclic and aromatic acids. These form, with low and high molecular weight substances, liquid and low viscosity compositions with very high plasticizing effects. However, the obtained coating and printing films are already too soft for some applications.

This disadvantage is overcome by the present invention, which relates to a polyester binder, in particular for pigment pastes, and to a process for its preparation. % ester-linked radicals of 2 to 4 hydroxyl groups and 70 to 82 wt. ester-linked radicals of acyclic and aromatic C7-C22 monocarboxylic and dicarboxylic acids. The molar ratio of monocarboxylic and dicarboxylic acids is 1: 0.1 to <0.25.

The process of preparing a polyester binder is characterized in that the triglycerides of acyclic monocarboxylic acids having 14 to 22 carbon atoms are subjected to a catalyzed alcoholysis of C2 -C4 polyalcohols and the resulting intermediates are esterified with monocarboxylic and dicarboxylic acids having 7 to 12 carbon atoms. its functional derivatives.

The reactions are carried out at a temperature of 160 to 260 ° C in an inert atmosphere or in the presence of an azeotropic solvent. At the same time, the reaction by-products are distilled off until the polyester acid number is below 20 mg KOH / g.

The polyester binder prepared according to the invention has some advantages over similar binders. Thus, the physical-mechanical properties of the cured binders can be varied to a large extent by the choice of the various types and amounts of starting acyclic saturated and unsaturated carboxylic acids and in particular triglycerides, polyalcohols, aromatic monocarboxylic and dicarboxylic acids or their anhydrides.

In particular, a substantial increase in the hardness of the crosslinked products is achieved while maintaining the required flexibility and impact resistance. This is mainly used in processing binders for paints, as well as printing and marking inks.

Both inorganic and organic pigments disperse well in the binder to provide concentrated pastes with high tinting efficiency.

Polyalcohols having 2 to 4 hydroxyl groups having an average molecular weight of 62 to 6,000 are suitable for the synthesis of the polyester binder of the invention. They include glycols / ethylene glycol, propylene glycols, butylene glycols, neopentyl glycol, diethylene glycols, dipropylene glycol, triethylene glycol and other polyalkylene glycols 2- and 1,4-cyclohexanediol, 1,4-bis (hydroxymethyl) cyclohexane), hydrogenated or alkylene-oxidized bisphenols (2,2-bis / 4-hydroxycyclohexyl) propane, 2,2-bis (4-hydroxyethoxyphenyl) propane, 2,2-bis (4-hydroxypropoxyphenyl) propane; trivalent alcohols (glyoerol). 1,1,1-trimethylolethane, 1,1,1-trimethylolpropane, 2,3,4-pentatriol, 1,2,3-trihydroxybutane, 1,2,6-hexanetriol, tris (2-hydroxyethyl) isocyanurate, z alcohols especially pentaerythritol. The polyalcohols are then used singly or in admixture with each other.

Of the monocarboxylic acyclic acids, those derived from the natural oils of drying / linseed, wood, light, rapeseed, oiticic, duvet, ricinine, fish /, semi-drying / soybean, tall, cotton, sunflower / non-drying / coconut, castor, peanut.

These acids form mixtures of saturated and / or unsaturated monocarboxylic acyclic acids. Of the saturated acids, important are caproic, caprylic, capric, lauric, myristic, palmitic, stearic, peanut, behenic and lignoceric acids.

Unsaturated acids are represented by oleic, irnolic, linolenic, alpha and beta-oleostearic, erucic, ricinoleic, 9,11-ricineiiic acids. In addition to these acids, it is also possible to use saturated synthetic acyclic acids (neoacids, Koch acids), 2-ethylhexanoic acid, pelargonic acid and others.

The starting acids are those of the individual acids, mixtures thereof, different fractions or their functional derivatives, of which are mainly the esters of aliphatic monocarboxylic acids with monohydric alcohols (in particular methyl esters) or polyhydric (in particular glyoerides).

The monocarboxylic aromatic acids are predominantly represented by benzoic acid or its substituted or also functional derivatives. These include, in particular, p-tert-butylbenzoic acid, m- and p-hydroxybenzoic acid, and halogen derivatives.

Suitable dicarboxylic acids are, in particular, aromatic phthalic acids, their functional and substituted derivatives. Phthalic anhydride, isophthalic acid and terephthalic acid, tetrachlorophthalic anhydride, tetrabromophthalic acid, tetrahydrophthalic acid, 3,6-endomethylenetetrahydrophralic acid, hexachlorenedomethylenetetrahydrophthalic acid and hexahydrophthalic anhydride are the most important.

acyclic dicarboxylic acids include, for example, sebacic acid, pimelic acid, azelaic acid, and dimeric acyclic acids.

Said monocarboxylic and dicarboxylic acids or derivatives thereof are used in a molar ratio of 1: 0.1 to 0.3 relative to each other. Depending on the molar ratios of these acids and polyalcohols, polyester binders containing 18 to 30 wt. ester-linked radicals of polyalcohols of the general formula

R - / 0 / _2-6 and 70 to 82% by weight. ester-linked carboxylic acid residues of the general formula

R is an acyclic or cyclic radical of a polyalcohol, r 'is an acyclic or aromatic radical of a monocarboxylic and dicarboxylic acid.

The preparation of the polyester binder is usually carried out in a stirred reactor equipped with a jacket for heating and cooling, an azeotropic adapter and optionally a device for measuring viscosity or conductivity. Preferably, a two-step process is used in the present invention.

In this process, firstly, triglycerides of acyclic monocarboxylic acids, i.e. natural, high-drying, semi-drying and non-drying oils, are introduced into the reactor, followed by polyalcohol, and the oil is alcoholized at a temperature of 200 to 260 ° C.

The reaction takes place under the catalytic action of alkaline reacting and other catalysts, such as oxide, lead acetate and naphthenate, calcium oxide, sodium or potassium hydroxide, sodium carbonate and organic tin compounds.

It is operated in the presence of a small amount of organic azeotropic solvents or in a melt and inert gas atmosphere. The resulting partial esters, in the case of glycerol alcohol monoglycerides, are subjected in the second stage to esterification with monocarboxylic and dicarboxylic acids or their anhydrides. It is esterified without addition of catalysts at 160 to 260 [deg.] C. while the by-products are distilled off.

The two-step process can also be carried out by first acidolysis of the acyclic monocarboxylic acid triglycerides with isophthalic acid, followed by esterification with a polyalcohol.

A one-step process is also suitable for synthesizing the polyester binder of the present invention. This involves direct esterification of the polyalcohol with acyclic monocarboxylic acids obtained from natural oils, monocarboxylic and dicarboxylic aromatic acids or their anhydrides. β

The esterification takes place at a temperature of 160 to 230 ° C without or in the presence of catalysts, again in the melt under an inert gas atmosphere or with the addition of an organic solvent.

The progress of the reaction is monitored by determining the acid number, hydroxyl number or even viscosity and conductivity measurements. The final product has an acid number below 20 mg KOH / g.

The polyester binder according to the invention is particularly suitable for the preparation of pigment tint pastes, paints, printing and marking inks. Either forms a separate binder component or is used in combination with other binders with which it is well miscible.

The invention is illustrated by the following examples.

Example 1

Polyester binder

The binder contains 22.5 wt. % ester-linked glycerol and pentaerythritol residues and 77.5 wt. ester-linked acyclic monocarboxylic acid residues of linseed oil (C18-22 number), benzoic acid and o-phthalic acid. The molar ratio of monocarboxylic and dicarboxylic acids is 1: 0.135.

The polyester binder is prepared by heating and holding the feed at 240 ° C with 879 g of linseed oil (containing 789 g of ester-linked acyclic monocarboxylic acid residues and 90 g of ester-linked glycerol residues) together with 525 g of pentaerythritol and 0.13 g of PbO. C for 2 hours.

After cooling to 170 ° C, 1,220 g of benzoic acid and 259 g of phthalic anhydride are added and the mixture is gradually heated to 240 ° C with constant evacuation of the water evolved. Terminate when the acid number falls below 20 mg KOH / g.

This binder has a viscosity of 300 mPa.s in the form of a 70% solution in butylene glycol and is very miscible with oil alkyds of oil length 30 to 72, epoxy, nitrocellulose binder and, to a limited extent, aqueous dispersions of the styrene-acrylate type.

Example 2

Polyester binder

The binder contains 20 wt. % ester-linked glycerol and pentaerythritol residues and 80 wt. ester-linked soybean oil acyclic monocarboxylic acid residues (C 14-22 atoms), benzoic acid and isophthalic acid. The molar ratio of monocarboxylic to dlcarboxylic acids is 1: 0.173.

This polyester binder was prepared by adding 415 g of isophthalic acid to 879 g of soybean oil (containing 789 g of ester-linked acyclic monocarboxylic acids and 90 g of ester-linked glycerol residues).

The mixture was heated to 270 ° C with stirring and CO _{2 addition} and maintained at this temperature for 2 hours. It is then cooled to 230 DEG C., 510 g of pentaerythritol and 893 g of benzoic acid are added. It is gradually heated to 240 ° C with constant removal of the reaction water. Terminate when the acid number drops to 10 mg KOH / g.

This binder has an 80% solution in a mixture of xylene and white spirit in wt. ratio 1: 1 viscosity 300 mPa.s.

Example 3

Polyester binder

The polyester binder contains 28.1 wt. % ester-linked trimethylolpropane and polyethylene glycol residues having a molecular weight of 300 and 71.9 wt. ester-linked acyclic monocarboxylic acids of safflower oil, p-tert. butylbenzoic acids, isophthalic acids and terephthalic acids. The molar ratio of monocarboxylic and dicarboxylic acids is: 0.1.

The binder is prepared by reacting 850 g of acyclic monocarboxylic acids obtained by cleavage of safflower oil, 1246 g of p-tert. butylbenzoic acid, 166 g of technical isophthalic acid / contains 5 wt. terephthalic acid), 300 g of polyethylene glycol having a molar mass of 300 and 495 g of trimethylolpropane, at 260 DEG C. in the presence of 100 g of xylene as an azeotropic agent. The esterification was terminated when the acid number reached 3 mg KOH / g.

This binder, in the form of a 70% solution in butyl glycol, has a viscosity of 110 mPa.s.

He attaches

Polyester binder D

The binder contains 23.3 wt. % ester-linked ethylene glycol and pentaerythritol residues and 76.7 wt. ester-linked acyclic acid residues of low-rape rapeseed oil, benzoic acid and o-phthalic acid. The molar ratio of monocarboxylic and dicarboxylic acids is 1: 0.23.

The binder was prepared by adding 700 g of pentaerythritol, 0.05 g of PbO and 0.10 g of CaO to 879 g of low-yield rapeseed oil (containing 789 g of ester-linked acyclic acid residues and 90 g of ester-linked glycerol residues).

Under CO ₂ , the mixture was heated to 260 ° C and after 2.5 hours cooled to 180 ° C. 1220 g of benzoic acid, 478 g of phthalic anhydride and 31 g of ethylene glycol are then added and the mixture is heated to 230 ° C.

The reaction was terminated when the acid number of the product was 9 mg KOH / g. A 75% solution of this binder in butyl glycol has a viscosity of 175 mPa.s.

Claims (2)

SUBJECT OF THE INVENTION Polyester binder, in particular for pigment pastes, characterized in that it contains 18 to 30 wt. % of ester-linked polyalcohol alcohols having 2 to 4 hydroxyl groups and 70 to 82 wt. ester-linked acyclic and aromatic radicals of 7 to 22 carbon atoms, wherein the molar ratio of monocarboxylic and dicarboxylic acids is 1: 0.1 to <0.25. 2. Process for preparing a polyester binder according to claim 1, characterized in that the triglycerides of the acyclic monocarboxylic acids having 14 to 22 carbon atoms are subjected to a catalyzed alcoholysis of polyols having 2-4 hydroxyl groups and the resulting intermediates are esterified with monocarboxylic and dicarboxylic acids having 7-12 atoms. carbon or functional derivatives thereof, wherein the reactions are carried out at a temperature of 160 to 260 ° C in an inert environment in the presence of an azeotropic organic solvent while distilling off the reaction by-products until a polyester acid value below 20 mg KOH / g is reached.