CS252660B1 - Method of polyurethanes production - Google Patents

Abstract

The solution relates to the preparation of polyurethanes using industrial by-products production of polyurethanes. The essence of the solution it consists in being like a polyol component contains the product containing it 2 to 98 wt. reaction product treating the polyurethane reaction residue blends from the production of polyurethane for cleaning production chambers % of equipment and containing 2 to 80 wt. chlorinated hydrocarbon as flushing agents with 0.1 to 10 wt. part Reagents with Unity functional group with active hydrogen in the molecule > usually with monovalent alcohols with 1 to 12 carbon atoms per molecule at 1 part of the reaction mixture.

Description

The present invention relates to a process for the preparation of polyurethanes using by-products from industrial polyurethane production.

It is known that polyurethanes are prepared by polyaddition reaction of di- to polyisocyanates with active hydrogen-containing compounds with the participation of additives. Basically, three types of polyurethane foam production process are possible:

A method of treating a prepolymer, i.e., reacting a polyol with an excess of di- or polyisocyanate in the first step, so that the resulting prepolymer contains isocyanate functional groups.

In the second step, the prepolymer is combined with a chain extender. If water is used, carbon dioxide is produced, which is the primary blowing agent. For example, if the extender is an aromatic diamine, blowing agents, usually water or low boiling fluorocarbon, are added.

2. A quasi-prepolymer treatment method in which a portion of the polyol is reacted with an excess of di- or polyisocyanate in a first step and the product is then combined in a second step with a polyol residue, a chain extender and other additives.

3. One shot ¹¹ , ie a one-step production method. The blend is prepared in the form of a blend (polyol, chain extender, additives, etc.), but all reactions with the isocyanate component take place simultaneously at the time of foam formation. All types of polyurethane foam are currently prepared in this way. The difference between them lies in the polyol used and the chain extender, respectively in the crosslinking agent.

Of the active hydrogen compounds, the polyhydroxy compounds of the so-called polyols are used in particular. Polyols are polymer products of either the ether or ester type. Polyesterpolyols are the products of predominantly anionic oxiranpolymerization, most commonly propylene oxide and ethyl oxide, and more rarely cyclic ethers such as tetrahydrofuran. The product is always a mixture of polymer homologues, characterized by a mean molecular weight, functionality, primary and secondary group fraction and degree of purity, for example, for hot foams of 3,000 molecular weight and functionality 3, for cold foams of 4,800-6,000 molecular weight and functionality 2.5 to 3. Detailed values are given in the specifications of each manufacturer.

Polyester polyols are prepared by esterification of terephthalic acid and adipic acid most often with diols, triols, tetrols and polyfunctional hydroxyl compounds such as sugars. The product is again polymer homologues. The possibilities of their synthesis are more limited, but almost exclusively contain only primary hydroxyl groups.

Also used are polyester polyols made from secondary raw materials - for example, by esterification of by-products of the cyclohexanone synthesis / MS. No. 233,472), or by esterification of distillation residues from the production of dimethyl terephthalate. author's certificate no.

209,504 /. In addition to the polyol types mentioned above, polyols based on polythioether / NSR pat. 1,105,156) or polyacetals (Germany) Pat. No. 1,039,444 and German Pat. 1,045,095 /. It is also known to use polymeric polyols prepared by polymerizing vinyl, acrylic, styrene or other monomers in the presence of conventional polyols in situ. The technical literature of British Petrol is particularly extensive in this respect.

It is also known to use so-called filled polyols. In addition to conventional inorganic fillers, the practical use of which is limited by special production equipment, the reactive type of filler developed by Bayer / NSR Pat. F 39 001 (1963)]. It is a branched solid product of polyaddition of polyisocyanate, polyamine and polyester polyol dispersed in polyol. Similar patents are Belgian / Belg. U.S. Pat. 829,122 (1974) and Belg. U.S. Pat. 829 123 (1975)]. Their purpose is to increase the hardness of the polyurethane foam.

In addition to the polyol, chain extenders or crosslinkers are used - generally low molecular weight substances with hydroxyl or amine groups and functionalities greater than or equal to 2, catalysts usually of the amine and / or organometallic type, etc.

Of the isocyanate compounds, 2,4- and 2,6-toluylene diisocyanate and polymeric diphenylmethane-4,4-diisocyanate, polymethylene polyphenylene isocyanate, or mixtures thereof or isocyanate prepolymers thereof are most commonly used commercially.

The present invention provides a process for the preparation of polyurethane from active hydrogen-containing compounds, di- to polyisocyanate and auxiliaries, wherein the polyol component comprises from 2 to 98% by weight, preferably from 5 to 80% by weight, of the reaction product formed. by treating the residues of the polyurethane reaction mixture resulting from the polyurethane production while cleaning the mixing chambers of the production apparatus and containing 2 to 80 wt. % of a chlorinated hydrocarbon as a scavenger using 0.1 to 10 wt. 1 part by weight of a reagent having one active hydrogen group per molecule, as a rule with monovalent alcohols having 1 to 12 carbon atoms per molecule, per 1 part of the reaction mixture.

Therefore, the waste material is practically utilized at the place of its origin, thus solving not only the ecological problem, ie waste disposal, but also the economic one, because valuable raw materials are saved. The process for the production of the polyurethane according to the invention makes it possible to use conventional and known technological equipment. Further details follow from the examples.

Example 1

For the preparation of semi-rigid polyurethane foam:

polyol with hydroxyl number 34 and functionality 3 90 g product A 10 g triethanolamine with hydroxyl number 1 130 and functionality 3 5 g water 2.5 g monofluorotrichloromethane 5 g amine catalyst 0.5 g crude MDI / 30 to 31% NCO. functionality 2.7 / 50 g

Product A was prepared from the remainder of the reaction mixture, rinse and reagent composition:

a / reaction mixture:

polyol with hydroxyl number 35 and functionality 3 100 g triethanolamine with hydroxyl number 1 130 and functionality 3 5 g water 2,5 g monofluorotrichloromethane 5 g amine catalyst 0,5 g crude MDI / 30 to 31% NCO, functionality 2,7 / 50 gb / purifier methylene chloride 5 - 120 gc / reagent ethyl alcohol 29 g

The reagent was fed together with the flushing agent into the mixing chamber of the GN 25 to 22 low pressure foaming machine containing the above-mentioned reaction mixture residues.

The foam obtained had a volume, a density of 68 kg.m ^-3 , a tensile strength of 0.42 MPa and an elongation of 75%.

Example 2

For the preparation of rigid polyurethane foam:

polyol with OH number 450 and functionality 4 80 g product A / see. example 1/10 g product B 10 g monofluorotrichloromethane 35 g flame retardant 10 g catalyst 1 g stabilizer 1 g crude MDI / 30% NCO, functionality 2,7 / 130 g

Product B was prepared from the remainder of the rigid polyurethane foam reaction mixture, rinsing agent and reagent composition:

a / residues of reaction mixture polyol with hydroxyl number 450, functionality 4 100 g monofluorotriohormethane 40 g flame retardant 10 g catalyst 1 g stabilizer 2 g

MDI / 30% NCO, functionality 2,7 / 130 g b / extender methylene chloride 10 - 240 g c / reagent ethyl alcohol 85 g

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

Claims (1)

object of the invention) Process for preparing polyurethane from active hydrogen-containing compounds, di- to polyisocyanate and auxiliary substances, characterized in that the polyol component contains in an amount of 2 to 98% by weight, preferably 5 to 80% by weight. a reaction product formed by treating the remainder of the polyurethane reaction mixture resulting from the polyurethane production while cleaning the mixing chambers of the production apparatus and containing 2 to 80 wt. % chlorinated hydrocarbon rinsing agent with 0.1 to 10 wt. 1 part by weight of a reagent having one active hydrogen moiety per molecule, as a rule with monovalent alcohols having 2 to 12 carbon atoms per molecule, per 1 part of the reaction mixture. ,