DE1813950A1 - High-yield manufacture of thixotropic, - oxidation-drying urethane oils for use as - Google Patents

Abstract

The reaction between polysiocyanates and partial esters of polyhydric alcohols and long-chain unsaturated aliphatic acids takes place in the presence of polyamide resins at temps. 50-100 degrees C., preferably 90 degrees C. The reaction temp. being lower than the usual 200 degrees C., prevents decomposition of the product. The polyamide resins are the products of reaction between low mol. wt. polyamines and dimerised aliphatic acids.

Description

Production of thixotropic urethane oils The invention is a Process for the production of thixotropic, oxidatively drying urethane oils.

It is already known that the implementation of partial esters from polyvalent Alcohols and long-chain unsaturated fatty acids with polyvalent isocyanates leads to so-called urethane oils, which are used as binders for oxidatively drying paints and colors can be used. You have comparable to others Coating raw materials such as alkyd resins have the advantage of improved drying speed and greater abrasion resistance.

Furthermore, in more recent times, by converting dimerized fatty acids polyamide resins obtained with polyamines on a large scale to thixotropic Alkyd resin binders have been used. For the production of thixotropic binders the alkyd resins are boiled with the polyamide resins at temperatures above 200 ° C. Thixotropic alkyd resins produced in this manner have grown in popularity in recent years Tried and tested as a binding agent for paint materials, their reduced sagging thicker layers of paint and their reduced tendency to drip off the pin; el makes this particularly suitable for use by non-specialists.

A corresponding production of thixotropic binders based on Urethane oils cannot be carried out, as these are required at the required high Reaction temperatures above 2000C are not stable.

It was therefore the object of a method for production by means of To find polyamide resins of thixotropic urethane oils, which in their other binder properties are not changed compared to the usual urethane oils.

This object is achieved in that one leads to urethane oils Implementation of partial esters from polyhydric alcohols and long-chain unsaturated ones Fatty acids with polyvalent isocyanates in the presence of polyamide resins.

The polyamide resins used to make the thixotropic urethane oils make commercial products with softening points between 90-2000C and amine numbers <5 (where the amine number indicates the mg KOH that the amine equivalent in one g Polyamide resin), which by converting dimerized fatty acids, which may contain low percentages of trimerized fatty acids, if appropriate in a mixture with monomeric fatty acids, with low molecular weight aliphatic polyamines, preferably ethylenediamine, can be obtained.

Another way of producing the polyamide resins is one Implementation of a mixture of the methyl esters of monomeric, di- and trimerized fatty acids of soybean oil or linseed oil with aliphatic polyamines, preferably ethylene diamine.

As an isocyanate component for the production of thixotropic urethane oils all come more commonly for the production up to now Used urethane oils polyvalent isocyanates in question, such as toluene diisocyanate, hexamethylene diisocyanate, 4,4'-diisocyanatodiphenylmethane, 1-chloro-phenyl-2,4-diisocyanate and others, alone or in a mixture.

The partial esters used for reaction with polyvalent isocyanates can be used as polyhydric alcohols, for example, glycerol, trimethylolethane, trimethylolpropane, 1,2,6-hexanetriol, 1,2,4-butanetriol, pentaerythritol and dipentaerythritol are the basis. All fatty acids or fatty acid mixtures can be used as acid residues in these partial esters be included, as they are generally used for the production of air-drying paints are known, such as linoleic, linolenic, ricinic, elaostearic acid or acids or acid mixtures, such as those made from soybean oil, linseed oil, sunflower oil, wood oil, dehydrated Castor oil (Ricin oil) or fish oils and tears can be obtained. The ones to use Partial esters can be obtained by esterifying each of the known processes desired polyhydric alcohols or their mixtures with the fatty acids in question or their mixtures. Another way of making the partial esters consists in the transesterification of the respective full esters, such as the natural drying ones Fats and oils (triglycerides) with polyhydric alcohols.

This preparation of the partial esters is carried out in a known manner. Temperatures around 2000C and optionally in the presence of esterification or transesterification catalysts vlie z ~ B.

free linseed oil fatty acids.

The production of thixotropic urethane oils is completely analogous to that the usual urethane fleece by repositioning the partial ester of polyvalent ones Alcohols and long-chain fatty acids with polyvalent isocyanates at temperatures 0 between 50-100 C in the presence of the required for the desired thixotropic effect Amount of polyamide resins. The reaction at temperatures can be particularly advantageous around 90 ° C. in the presence of inert solvents such as aliphatic or aromatic solvents Carry out hydrocarbons, e.g. white spirit, toluene or xylene. It will The reaction mixture is kept at about 90 ° C. until almost all of the isocyanate is implemented. A very small amount of free isocyanate groups that remains is effective do not interfere with the excess of hydroxyl groups in the partial ester the end. There is also the possibility of the reaction using catalysts such as them are common in urethane chemistry to accelerate. As a very suitable catalyst has proven to be dibutyltin dilaurate.

The amount of the polyamide resin used can vary as desired Degree of thixotropy 1 to 75 -, based on urethane oil. With an addition of 1% a certain influence on the viscosity is achieved with polyamide contents of 40% and more, the influence on viscosity is so strong that such products no longer as the sole binder, but only as a thixotropic agent in Mixtures of binders can be used.

The incorporation of such gel-like masses into others to be thixotropic Binder can be processed together on roller mills or other units as well as done by melting.

The following examples are intended to explain the invention in more detail. but without limiting it to this.

Examples The polyamide resin A used for the examples was based on Obtained in the following way: 824 parts by weight of dimerized soy fatty acid with approx.) The content of trimer fatty acid and 84.6 parts by weight of tallow fatty acid were measured under an inert gas atmosphere heated to 1200C. At this temperature, 91.4 parts by weight were obtained within 2 hours allowed to drip anhydrous ethylenediamine to the fatty acid mixture. After that was within 6 hours the temperature was increased to 2000C, and then was the reaction mixture was kept under vacuum at 2000 C until the amine number had dropped to about 3. It became the polyamide resin A with the following characteristics obtained: amine number 3.1, melting point 1120C (kof 1er bank), viscosity 50 / aig in Ethanol / toluene 1: 1 was 350 cP at 0-20 C.

For the production of the partial ester used for urethane oil production 560 g of linseed oil fatty acid with 136 g of pentaerythritol were down to an acid number lower esterified as SZ = 3. The esterification reaction was with the addition of so much white spirit performed, as required to set a boiling temperature of 2000C in the reaction mixture was. The resulting water of reaction was driven off with the boiling white spirit. After the reaction had ended, the ester obtained was adjusted to a solid resin content of 60 ffi with white spirit diluted.

Example 1 For the production of a urethane oil with thixotropic flow behavior 305 g of the above-described 60% partial ester solution in white spirit, 18.3 g of the polyamide resin A and 55.8 g of white spirit and heated to 120ob. After the polyamide resin had melted, the solution was cooled to 90 ° C. and 37.5 g of tolylene diisocyanate entered. The batch was kept at 90 ° C. until the content of free isocyanate groups had dropped to almost 0, including about 5 hours were needed. It became a urethane oil solution with thixotropic flow properties obtained, which are suitable for the production of so-called non-drip paints was.

Example 2 For the production of a urethane oil with thixotropic flow behavior became 305 g of the partial ester solution in white spirit show 3.7 g of polyamide resin A and 41.2 g of white spirit 0 melted together at 120 0. The clear solution was cooled to 9000 and after the addition of 37.5 g of toluylene diiso-0 cyanate for so long 90 ° C held until the content of free isocyanate groups has fallen to almost zero was. This took about 4 hours. A urethane solution resulted with weak thixotropic properties, which are suitable for the production of hammer effect paints proved suitable.

Example 3 To produce a highly thixotropic urethane oil, 305 g of the 60% partial ester solution in white spirit, 147 g of polyamide resin A and 123 g white spirit heated together to 1200C until the polyamide resin was dissolved. To Cooling to 90 ° C, 37.5 g of toluene diisocyanate were added to the solution and the The batch was kept at 90 ° C. for 5 hours. After this time there were no free ones Isocyanate groups are more present. A very firm gel was obtained, which as such is not suitable as a binder for paints. By training small amounts of this gel in the binder components of lacquers or paints Melting together or on the roller mill can use the paints in question ground thixotropic properties.

The method according to the invention is easy to use Opportunity has been found to give urethane oils thixotropic properties, without changing their other favorable properties disadvantageously.

Claims (4)

Claims 1. Process for the production of thixotropic, oxidatively drying urethane oils, characterized in that one converts partial esters leading to urethane oils from polyvalent alcohols and long-chain unsaturated fatty acids with polyvalent ones Isocyanates in the presence of polyamide resins. 2. The method according to claim 1, characterized in that the polyamide resins Reaction products of dimerized fatty acids with low molecular weight polyamines are used will. 3. The method according to claim 1 and 2, characterized in that the Implementation of the partial esters with the isocyanates in the presence of polyamide resins Temperatures of 0 0 50-100 C, preferably around 90 C, is carried out. 4. Thixotropic urethane oils, which are produced by converting partial esters and Isocyanates have been obtained in the presence of polyamide resins according to claims 1-3 are.