CS262334B1 - Treatment of residues of reaction mixture composed from polyole,isocyanate and assistant substances - Google Patents

Abstract

Process for the preparation of the reaction mixture from the production polyurethanes and / or polyurethane-isocyanurates in a one-step manner by feeding 0.1 to 0.15 wt. part of the compound which contains at least two groups with hydrogen atoms of different activity to isocyanates, preferably primary and / or secondary hydroxy and / or amino, preferably in admixture with aliphatic Cy to C10 alcohols in an amount of 0.1 to 9 wt. parts, each for 1 part of the reaction mixture and for the presence of a propellant, preferably chlorinated hydrocarbon. Modified Reaction the residues can be easily thermally or chemically breakdown into nitrogenous substances or biologically odbourat.

Description

The invention relates to a process for treating a reaction mixture from the production of polyurethanes and / or polyurethane isocyanurates in a one-step process, i.e., one shot.

In a one-step one shot process, the formation of macromolecular polyurethane foam is included in a single production cycle. In the case of polyurethane production, it also involves the formation of the final product, the entire manufacturing process being carried out in minutes.

The composition of the reaction mixture depends on the desired properties of the polyurethane foam and the quality of the raw materials used. The product of the exothermic reaction is a macromolecular polyurethane of elastomeric to thermosetting behavior, which cannot be transferred to a liquid or plastic state by heat, nor a solvent to a solution in which it only swells.

The reaction is effected by mixing components A and B of the reaction mixture, wherein component A typically contains a polyol, i.e. a hydroxyl-terminated functional group usually 3, furthermore typically contains cross-linking auxiliaries, usually low molecular weight hydroxyl or amine-terminated functional groups 2 and more, it further comprises water and a physical blowing agent such as monofluorotrichloromethane, catalysts and foam stabilizers, pigments, flame retardants, etc. Component B contains isocyanate-terminated substances. They are usually bifunctional to polyfunctional compounds.

For mixing and accurate dosing of components A and B are used so-called foaming machines, equipped with containers, chambers and stirrer. The components from the individual containers are brought under pressure into the mixing chamber, mixed with each other, and the reaction mixture thus formed is dosed by pouring into a designated space or mold. Since this is an intermittent operating cycle, the mixing chamber with the stirrer and the discharge tube must be cleaned of the remainder of the reaction mixture after the casting cycle is complete. This is usually done by injecting a scavenger, usually a chlorinated hydrocarbon, under pressure into the chamber, and the remainder of the reaction mixture is entrained with the scavenger as the chamber is emptied. The flushing of the chamber takes place automatically, by means of the device in a time shorter than the start time of the reaction. The reaction start time is the time from mixing the components to the start of the reaction and is usually 5 to 55 seconds. This causes the reaction of the isocyanate to take place outside the mixing chamber.

The waste is collected in waste containers in which the reaction mixture, consisting of a polyol component and an isocyanate, is reacted to a solid, cross-linked mass which cannot be returned to the liquid by heat or solvent. Waste is usually disposed of by incineration, generating marked smoke and toxic gases such as carbon monoxide, hydrogen cyanide, phosgene, etc.

Processes for the preparation of the remainder of the reaction mixture and the elimination of these disadvantages are known - Process for the production of polyurethanes (AO 252 660) and Process for the remainder of the reaction mixture (AO 247 724). They use compounds and / or mixtures of compounds with an average functionality of 1 to 2, preferably a monovalent alcohol having 1 to 12 carbon atoms, and / or mixtures thereof with water and chlorinated hydrocarbons. The reaction of the isocyanate with an excess of monovalent alcohols leads to the formation of low-molar liquid or chlorinated hydrocarbon-soluble methane compounds. When treating the treated residues of the reaction mixture in the polyurethane production process, they are likely to react with the isocyanate group via the urethane hydrogen group.

The disadvantage of working with lower alcohols is working with liquids, flammable substances of the 1st class, which require an explosion-proof environment or the use of special safety measures. Higher monovalent alcohols, with the isocyanate group, provide urethane compounds soluble in chlorinated hydrocarbons, which, however, fall out of solution on standing.

According to the present invention, the process for treating the remainder of the reaction mixture consisting of polyol, isocyanate and auxiliaries resulting from the single-stage production of polyurethane or polyurethane isocyanurate foam, in particular from the cleaning of the mixing chamber of the production apparatus, is carried out in such a way. 0.1 to 15 wt. parts by weight of the compound and / or the compounds containing at least two groups of hydrogen atoms of different isocyanate activity, preferably a primary and / or secondary hydroxy group and / or an amino group, preferably in admixture with aliphatic to alcohols in an amount of 0.1 to 9 wt. parts per 1 wt. % of the compound and in the presence of 0.1 to 30 wt. parts of flushing agent, preferably chlorinated hydrocarbons, per 1 wt. part of a compound containing at least two groups of 8 hydrogen atoms with different isocyanate activity.

In the treatment of the remainder of the reaction mixture according to the invention, the isocyanate preferably reacts with the supplied low molecular weight alcohols to form a low molecular weight urethane terminating hydroxyl group which remains permanently fluid even after the flushing agent has evaporated. If necessary, it can be treated, easily handled, collected and stored by adding solvent. In the process for the production of polyurethanes, the treated residues of the reaction mixture react with the isocyanate via a hydroxyl group hydrogen or a urethane group hydrogen.

The treated reaction residues can also be easily thermally or chemically decomposed into nitrogenous substances or biodegradable.

The great advantage of this process is the increase in work safety, easier processing of treated residues of the reaction mixture via the hydroxyl group and achieving better results. Further details of the process of the invention as well as other advantages are apparent from the examples.

Example 1

Into the mixing chamber of the low-pressure foaming machine GN 25 containing the residues of the reaction mixture of the polyol composition having a hydroxyl number of 35 and a functionality of 3,100 g triethanolamine with a hydroxyl number of 1,130 and a functionality of 3,5 g water 2.5 g monofluorotrichloromethane Crude MDI (30 to 31% NCO, functionality 2.7) 50.0 g was dosed with 120 g propylene glycol flushing agent (methylene chloride) 48 g

The product obtained from the remainder of the reaction mixture, the scavenger and the reagent is liquid and identical for further processing.

Example 2

A flushing agent (methylene chloride and isobutane in a 1: 1 weight ratio, 60 g propylene glycol 38 g glycerin 10 g) is metered into the mixing chamber of the low pressure GN 25 foaming machine containing the reaction mixture residues described in Example 1.

The product obtained is liquid and suitable for further processing.

Example 3

A flushing agent (methylene chloride / dichloroethane mixture in a 9: 1 g wt / wt ratio) was charged into the mixing chamber of the foaming apparatus containing the remainder of the reaction mixture described in Example 1.

propylene glycol 40 g ethanolamine 10 g

The product obtained from the residues of the reaction mixture, the flushing agent and the reagent is liquid and suitable for further processing, especially in the production of polyurethane foams.

Example 4

Into a mixing chamber of a foaming machine containing the residues of a reaction mixture of the polyol composition having a hydroxyl number of 28 and a functionality of 2.9 100 g water 2.6 g a mixture of amine and organometallic catalysts 0.8 g foam stabilizer 0.5 g monofluorotrichloromethane. 1 g polyurex 13.17 (44% NCO, functionality 2,1) 35 g dosed flushing agent (methylene chloride) 100 g propylene glycol 30 g synthetic ethanol 20 g

The product, prepared from the residues of the reaction mixture, the scavenger and the reaction compounds (propylene glycol, synthetic ethanol), is liquid and suitable for further processing.

Example 5

Into the mixing chamber of a foaming apparatus containing a polyol hydroxyl residue of 450 g KOH / g, functionality 4,100 g monofluorotrichloromethane 35 g flame retardant 10 g stabilizer 1 g catalyst 1 g MDI (30 to 31% NCO, functionality 2, 7) 130 g dosed flushing agent, (methylene chloride) 240 g monopropylene glycol 140 g

The product prepared from the residues of the reaction mixture, the scavenger and the monopropylene glycol is liquid.

For the preparation of rigid polyurethane foam:

polyol having a hydroxyl value of 450 mg KOH / g, functionality of 4 80 g product prepared from the reaction mixture residues, a scavenger and monopropylene glycol (according to Example 5). 10 g product prepared from residue and reaction mixture, scavenger and propylene glycol, according to example 1 10 g monofluorotrichloromethane 35 g flame retardant 10 g catalyst 1 g stabilizer 1 g

MDI (30 to 31% NCO, functionality 2.7) 130 g

The obtained rigid polyurethane foam has a bulk density of 33 kg / m ³ , a compressive strength at 10% compression of 0.15 MPa, reduced flammability and good dimensional stability.

Claims (1)

BACKGROUND OF THE INVENTION Process for treating the remainder of the reaction mixture consisting of polyol, isocyanate and auxiliary substances, originating from a single-stage production of polyurethane or polyurethane isocyanurate foam, in particular 2 cleaning of the mixing chamber of a production plant, characterized in that it is applied to 1 wt. a portion of the reaction mixture acts from 0.1 to 15 wt. parts of a compound and / or compounds containing at least two groups having hydrogen atoms of different isocyanate activity, preferably a primary and / or secondary hydroxy group and / or an amino group, preferably in admixture with aliphatic C ₁ -C ₄ alcohols in an amount of 0.1 to 9 wt. parts per 1 wt. and in the presence of 0.1 to 30 wt. parts of the flushing agent, preferably chlorinated hydrocarbons, per 1 wt. part of a compound containing at least two groups having hydrogen atoms of different isocyanate activity.