CS210990B1 - Process for producing polyurethane or polyurethane isocyanurate foams - Google Patents

Abstract

The invention relates to the preparation of polyether polyols for polyurethane foams and/or elastomers. It solves the neutralization of alkoxylation catalysts, in particular the neutralization of sodium hydroxide and potassium hydroxide, which have an adverse effect on the preparation of polyurethane polymers. The essence of the invention lies in the neutralization of alkoxylation catalysts using internal cyclic anhydrides of carboxylic acids.

Description

The invention provides a process for the production of polyurethane or polyurethane foams by reducing the catalytic activity of the alkali metals present in the polyol used.

Polyurethane foams are prepared by reacting aromatic and / or aliphatic and / or cycloaliphatic isocyanates having a functional group number greater than 1 per molecule, with compounds containing more than one active hydrogen per molecule, in the presence of a catalyst, a blowing agent, a stabilizer, an emulsifier and other additives.

Polyurethane isocyanurate foams are prepared by reacting compounds containing at least one active hydrogen with an excess of aromatic and / or cycloaliphatic and / or aliphatic isocyanates having a functionality greater than -1, whereby an isocyanate excess is formed from an excess of isocyanate by the use of a suitable trimerization catalyst. The reaction takes place in the presence of a blowing agent, a suds stabilizer and other desired additives in one step.

Another method of preparation involves the use of a modified isocyanate, where a controlled trimerization of a portion of the isocyanates is converted to isocyanurates.

It is also known to prepare a prepolymer in which a polyol is reacted with an excess of isocyanate to form an isocyanate-terminated prepolymer which in the next step forms a polyurethane isocyanurate foam in the presence of foaming agents and a trimerization catalyst. Compounds containing more than one active hydrogen in the structure are used to prepare polyurethane and / or polyurethane isocyanurate foams. Active hydrogen capable of reacting with isocyanates must comply with the Zerewitinoff test (J. Am. Chem. Soc. 49,

181 (1927).

This requirement is met by protons bonded in the primary, secondary hydroxyl group,-»» »= NH, -COOH, -CONH2 ^and others. For the formation of urethane bonds in polyurethane or polyurethane isocyanurate foams, a variety of polyols having a molecular weight of 62 to 4000, but in particular polyether polyols and polyester polyols, are used.

Polyether polyols prepared by alkoxylation of low molecular weight diols, trioles or polyols such as e.g. propylene glycol, ethylene glycol, trimethylolpropane, glycerine, pentaerythritol, sorbitol, glucose, sucrose, and the like, contain, as an alkoxylation catalyst, alkali hydroxides in a concentration of 0.01 to 1 Z. 10 ppm. In addition, it is known that alkali hydroxides in the presence of water greatly reduce the shelf life of the mixed polyol component. Methods for purifying and stabilizing polyether polyols are known from the patent literature.

The alkali metals are neutralized with inorganic or organic acids, such as e.g.

^H 2 ^S ° 4 ^(A · Brit. 958,380 ^{and the price} P, Japanese. Patent No. 20 743/63), oleic acid and / or alkylbenzínsulfonovou alkylto1uénsulfónovou / West Germany Patent No. 2737473 /, Hexafluorosilicic or fluoboric acid / W. Brit. U.S. Patent 892,557, Germany Patent 2,204,515), tartaric acid (V). Brit. No. 1,377,486), formic acid (French. U.S. Pat. No. 1,411,380;

554 228), phosphoric acid (jap.). U.S. Patent 24,287/64, USSR Patent 546,627, Polish Patent 9,055).

The resulting acid salt is removed from the polyether polyols by extraction with water / US patent

715,402, franc. U.S. Patent 2,174,670, or water-soluble polyethers are purified by adsorption of salts onto silica gel. U.S. Patent 4,139,718, U.S. Pat. No. 1,377,486), Al silicates or Mg silicates (jap. U.S. Patent No. 4,929,879, US Patent No. 4,929,879;

546,627 /. The adsorption on the solid sorbents is carried out in the presence of 2 to 25 from water.

Another possibility of removing alkali salts from the polyether polyols is to precipitate them, either by removing water from the neutralized polyethers and then filtering the precipitated salts / V. Brit. U.S. Patent 892,557, 958,390, jap. U.S. Patent 20,742/63, Germany Patent 2,204,515].

The precipitated salts can also be removed by centrifugation (German Patent No. 2,554,228).

Precipitation of alkali metal ions of insoluble compounds in the polyether polyol is also possible by the addition of sodium or ammonium bisulfite in the form of an aqueous solution. After refluxing and evaporation of water, the sodium sulfite precipitate is filtered off / V. Brit. U.S. Patent 958,390, a similar procedure is described (Polish Patent 94,408), wherein an aqueous solution of potassium bisulfite is used, and in German Patent No. 71,622, an aqueous solution of potassium hydrogen sulfate is used.

Further, the alkali metals may be precipitated with phosphorus trichloride in the presence of sodium, potassium or aluminum / Holland methoxide. U.S. Patent 73,117,479), respectively, with carbon dioxide in the presence of magnesium bicarbonate (U.S. Patent 2,208,614). Another way of neutralizing the adverse effect of alkali in polyether polyols is by binding them to reactive 2-compounds. Such a method is described in (NSR Patent 2,318,107), wherein the alkali is bound by a copolymer of styrene maleate anhydride or polyacrylic acid.

According to the present invention, a process for producing polyurethane or polyurethane isocyanurate foams from polyol and polyisocyanate in the presence of additives is carried out by treating the polyether polyol and / or polyol component with a polyisocyanate, phthalic anhydride and / or 3 to 10 wt. %, preferably 0.1 to 5 wt. to the polyol used.

The advantage of this process for the production of the polyether polyol component is the deactivation of alkali without the subsequent removal of chemically bound alkali, the amount and type of anhydride used being only a small cost item for producing the polyol.

A further advantage lies in the possibility of regulating the polyurethane reaction between the diisocyanate and the polyol, which is to some extent retarded by the action of carboxylic acids. This is particularly welcome when polyols with primary low molecular weight hydroxyl groups are used. In such cases, an excess of dicarboxylic acid anhydride may also be used, depending on the desired course of the polyurethane reaction.

In the production of polyurethane isocyanurate foams, it is in turn advantageous to neutralize the alkali to a concentration such that the trimerizing effect of the alkali is utilized as required by the reaction.

Usually, the synergistic effect of a mixture of a tertiary amine with an organic stannous compound is utilized in activating the polyurethane reaction. N, N-dimethylcyclohexylamine, triethylamine, N, N ' -diazabicyclooctane, N-methylmorpholine, N, N-diethylthiolamine compounds are nitrogenous compounds such as dibutyltin dilaurate, dibutyltin dioleate.

The trimerization of isocyanates in the preparation of isocyanurate foams is activated by trimerization catalysts, in particular by alkaline hydroxides: aqueous solutions of sodium, potassium, lithium, or alkaline salts of weak acids such as sodium bicarbonate, potassium, sodium acetate, potassium acetate, sodium octoate, potassium. Ternary amines of the Mannich base type, such as 2,4,6-tris / dimethylaminomethyl / phenol or 2,6-di- (dimethylaminopropyl) -4-nonylphenol, also triazine derivatives, e.g. -tris (dimethylamino-propyl) -syra-hexahydrotriazine, and other derivatives thereof.

The synergistic effect of a mixture of a tertiary amine and an epoxide is also known, wherein triethylamine, N, N-dimethylcyclohexylamine, N-methylmorpholine, N, N-diazabicyclooctane and others such as epoxide, propylene cyanol, epichlorene oxide, phenyl ether and other.

The blowing agents used in the preparation of polyurethane or polyutethanisocyanurate foams are predominantly different types of fluorochloranes, such as freon 11, freon 12, freon 111, freon 112, but other low boiling substances such as acetone, ethyl3 acetate, diethyl ether may also be used. , chloroform, dichloromethane, vinyl chloride, vinylidene chloride, trichlorethylene. Substances which cleave nitrogen at elevated temperatures, such as azo-bis-isobutyronitrile or formaldehyde, may also be used. The reaction of isocyanates with water for the cleavage of carbon dioxide can also be utilized partially or completely for the blowing of the reaction mixture.

The presence of stabilizers in the reaction mixture ensures uniformity of foam cell formation and size. The most commonly used are silicon organic compounds of the type polysiloxane polyalkylenes.

The importance of the emulsifier is to improve the mutual miscibility of the blowing agent with the polyol and the whole polyol component with the polyisocyanate.

The second major component for the preparation of polyurethanes and polyurethane isocyanurates is polyisocyanates. Crude 4,4'-diisocyanatodiphenylmethane is particularly preferred for the preparation of particularly rigid foams, but hexamethylene diisocyanate, 2-, 4-toluene diisocyanate, 2,6-toluene diisocyanate or an 80:20 or 65:35 mixture of isomers 2 may also be used, 4- / 2,6-toluene diisocyanate, further ethylene diisocyanate, butylene diisocyanate, 3,3 ^- dichloro-4,4 ^- diisocyanatodiphenylene, 1,5-naphthylenediocyanate and other derivatives and mixtures thereof.

Other advantages of the present invention are evident from the exemplary embodiments.

EXAMPLE

Up to 50 g of distillation residues from the distillation reaction product of ethylene oxide hydrolysis reaction composed of about 95% triethylene glycol and 5% tetra-, pentaerylene glycol and other higher addition products containing 1 500 ppm sodium and 60 ppm potassium with a hydroxyl number of 773 mg KOH / g and a water content of 0 1 wt. 0.5 g of Tegostab B 1903 silicone stabilizer, 0.5 g of Slovasol SF emulsifier, 32 g of Freon blowing agent Ledon 11 are added. After complete mixing, 100.4 g of crude 4,4-diphenylmethane diisocyanate under the commercial designation Desmodur 44V are added and turbine is added. the stirrers are stirred shortly. Almost immediately after mixing, the reaction begins with rapid heat generation, resulting in internal combustion of the foam, which also has a very poor structure.

Example 2

000 g of the distillation residue specified in Example 1 are mixed with 6.1 g of phthalic anhydride and heated to 100 ° C with stirring for 30 minutes. The reaction mixture was allowed to cool to room temperature. Polyurethane foam prepared from 50 g of polyol so treated, 0.5 g of Tegostab B 1903 stabilizer, 0.5 of Slovasol SF emulsifier, 32 g of Ledon 11 blowing agent and 100.4 g of Desmodur 44V polyisocyanate have a start time of 12 seconds, a growth time of 22 seconds and adhesive loss of 26 seconds, density 27.4 g / cm, good dimensional stability at -30 ° C and fine uniform texture.

Example 3

The polyurethane isocyanurate foam prepared from the modified polyol according to Example 2 is composed of 30 g of modified polyol, 1.8 g of stabilizer B 1903, 1.8 g of Slovasol SF emulsifier, g of blowing agent Ledon 11, 0.2 g of 50% potassium acetate solution. ethylene glycol and 231.5 polyisocyanate Desmodur 44V have a start time of 20 seconds, a growth time of 60 seconds and a tack loss of 75 seconds. The isocyanate index 400 has a very low friability, bulk density q

34.5 g / cm and ASTM D 1692 is self-extinguishing.

Example 4

The distillation residues specified in Example 1 and treated as described in the Example

2, 5.2 g of phthalic anhydride per kg of residue are used for the preparation of polyurethane

21Q990 foam of 50 g treated residue 0.5 g Slovasol SF emulsifier, 0.5 g Tegostab B 1903 stabilizer, 32 g Ice 11 is mixed together with 100.4 g Desmoduru 44V polyisocyanate. * The foam has a Start / Time of 20. seconds, .the growth. 35 seconds. and a loss of stickiness of 40 seconds, a density of 28.7 g / cm @ 2.

Example 5

The distillation residues specified in Example 1 having a hydroxyl value adjusted to 470 mg KOH / g, further ethoxylated, have a total alkalinity of 10 mg KOH / g. 500 g of the residue thus treated are neutralized with 8.8 g of maleic anhydride as described in Example 2.

Polyurethane foam prepared from 50 g of neutralized polyol, 0.5 g of Tegostab B 1903, 0.5 g of Slovasol SF emulsifier, 22 g of Ledon 11 blowing agent and 61 g of Desmodur 44V polyisocyanate have a start time of 13 seconds, a growth time of 35 seconds and a loss 39 seconds. The foam with a fine balanced structure has a bulk density of 27.2 g / cm.

Example 6

The distillation residues specified in Example 1, treated by further propoxylation to a hydroxyl value of 455 mg KOH / g have a total alkalinity of 9.7 mg KOH / g, 500 g of the propoxylated residues are neutralized as described in Example 2 with 17.6 g maleic anhydride.

A polyurethane isocyanurate foam prepared from such a treated polyol, in the presence of 30 g polyol, 1.8 g stabilizer B 1903, 26.4 g blowing agent F 11 and 0.2 g trimerization catalyst consisting of 50% potassium acetate solution in ethylene glycol and 2.4 g. 6, 6-bis (dimethylaminomethyl) phenoxy, 1: 1 by weight, and at the isocyanate index 400 with 152.3 g of Desmodur 44V polyisocyanate, the foam has a start time of 40 seconds, a growth time of 120 seconds and 3 tack loss of 200 seconds; g / cm and according to ASTM D 1692 is self-extinguishing.

Claims (2)

21Q990 Foams of 50 g of treated residues 0.5 g of Slovasol SF emulsifier, 0.5 g of Tegostab B 1903 stabilizer, 32 g of Ledon 11 are mixed with 100.4 g of Desmodur polyisocyanate 44V. , .dohu rastu. 35 seconds. and loss-tack-40 .mu.m, volume weight 28.7 g / cm @ 2. EXAMPLE 5 The distillation residues specified in Example 1 with a modified hydroxyl number of 470 mg KOH / g, further ethoxylation have a total alkalinity of 10 mg KOH / g. 500 g of the thus treated residues are neutralized with 8.8 g of maleic anhydride as described in the Example 2. Polyurethane foam prepared from 50 g of such neutralized polyol, 0.5 g of Tegostab B 1903 stabilizer, 0.5 g of Slovasol SF emulsifier, 22 g of Ledon 11 blowing agent and 61 g of Desmodur 44V polyisocyanate having a starting time of 13 seconds, growth time 35 seconds and loss of stickiness 39 seconds * Foam with a fine leveled structure has a bulk density of 27.2 g / cm. EXAMPLE 6 The distillation residues specified in Example 1, further propoxylated to a hydroxyl number of 455 mg KOH / g, have a total alkalinity of 9.7 mg KOH / g, 500 g propoxylated residues are neutralized as described in Example 2 with 17.6 g maleic anhydride. Polyurethane isocyanurate foam prepared from the thus treated polyol, in the presence of 30 g of polyol, 1.8 g of stabilizer B 1903, 26.4 g of blowing agent F 11 and 0.2 g of a trimerization catalyst consisting of 50 of a solution of potassium acetate in ethylene glycol and 2.4.6 1: 1 bis-dimethylaminomethylphenol and 152.3 g of isobisocyanate Desmodur 44V with an isocyanate index 400 with a starting time of 40 seconds, a growth time of 120 seconds and a loss of tack of 200 seconds, a bulk density of 35.4 g / cm and according to ASTM D 1692 quenching. OBJECT OF THE INVENTION A process for the production of polyurethane or polyurethane isocyanurate foams from polyol and polyisocyanate in the presence of additives, characterized in that the polyether polyol and / or polyol component is pre-treated with polyisocyanate, phthalic anhydride and / or maleic anhydride - 3 ndom. in a concentration of 10 to 10% by weight, preferably 0.1 to 5% by weight; to the polyol used. Severografia, n. P., Plant 7, Most