DD251150A1 - METHOD FOR PRODUCING POLYOLS WITH URETHANE STRUCTURE - Google Patents

Abstract

The invention relates to a process for the preparation of polyols having a urethane structure, which are suitable for use in polyurethane systems. The aim of the invention is to develop a process for preparing urethane-containing polyols from isocyanate-containing distillation residues and hydroxyl components, including inexpensive raw materials while largely avoiding additional technological effort. According to the invention, the object is achieved in that the hydroxyl components of the reaction mixture are partially replaced by primary and / or secondary amines. In principle, all OH-functional compounds with boiling point 100C are used as the hydroxyl components. In particular, waste amines from polyurethane chemistry can be used as amines.

Description

Field of application of the invention

The invention relates to a process for the preparation of polyols with Urethanstmktur, which are suitable for use in polyurethane systems.

Characteristic of the known technical solutions

Methods are known in the literature for the preparation of urethane-structured polyols. They are based on the reaction of polyol components of different molecular weights with di- or polyisocyanates when using a stoichiometric excess of the hydroxyl component. Such modifications are mainly carried out to obtain polyols with compared to the classical polyols (prepared by alkoxylation of starter substances with ethylene and / or propylene oxide) significantly reduced proportion of ether groups. If aromatic isocyanates are used as the polyol raw material, then the resulting aromatic content of the polyol has a negative effect on the product viscosity, but on the other hand leads to the known positive effects with regard to the polyurethane properties. By using urethane-modified polyols in the production of polyurethane systems, it is therefore possible to produce materials with reduced sensitivity to the action of fire and heat, whereby the use of special flame-retardant additives can be avoided or minimized. According to the prior art, urethane-containing polyols are prepared essentially by two processes, on the one hand by combining di- or polyisocyanates with high-quality hydroxyl components, for example diethylene glycol and / or dipropylene glycol, on the other hand by combining isocyanate waste products, for example isocyanate-containing distillation residues high quality hydroxyl components (WP C08 G / 237 276).

To reduce the cost of raw materials has also been proposed to use in place of the above alcohol components whose alkaline crude products, as obtained in their generally conventional method of preparation, the alkali-catalyzed anionic Alkylenoxidaddition, as intermediates (WP CO8G / 250811).

Although this achieves a certain cost saving, but especially when using distillation residues as the isocyanate component and thereby causing production of lower quality polyols, this cost saving is not enough to make the desired broad application of the product look lucrative. Another deficiency of the prior art is that an increase in the aromatic content in the polyol at the same hydroxyl value is practically impracticable, because increasing the content of aromatic isocyanates in the polyol formulation on the one hand, the viscosity of the product would increase disproportionately and on the other alcohol components high hydroxyl number would have to be used, for example, ethylene glycol, which would lead to poor propellant and isocyanate compatibility of the polyol and embrittlement in the resulting polyurethane material. The use or an increase in the use of aromatic-containing alcohol components, such as Propoxylierungsderivaten of aniline, is not economical.

Object of the invention

The aim of the invention is to develop a simple, safe and economically favorable process for the preparation of urethane-containing polyols.

Explanation of the essence of the invention

The invention has for its object to develop a technologically simple process for the preparation of urethane group-containing polyols from isocyanate-containing distillation residues and hydroxyl components, including inexpensive raw materials while largely avoiding additional technological costs.

According to the invention the object is achieved in that the hydroxyl components are partially replaced by primary and / or secondary amines. The preparation of the urethane-containing polyol is carried out in a known manner by reacting the reactants with liquid or solid isocyanate-containing distillation residues at temperatures <250 ° C, optionally additives, such as compounds with carbon chains and epoxides can be added. In principle, all OH-functional compounds having boiling points> 150 ^° C. can be used as the hydroxyl components. Particularly suitable are di- and triols, such as ethylene glycol and its homologues, propylene glycol and its homologues, butanediol (1.3) and its condensation products, glycerol and trimethylolpropane and alkoxylation products of amines.

The partial substitution of the present invention the hydroxyl moieties by primary and / or secondary amines can C through all the NH-functional compounds having boiling points> 100 ^0, preferably aniline and its condensation products, tolylene, cyclohexylamine, N-alkylamines, Dioxohexahydrotriazin, fatty amines and / or mixtures which contain these amines done. The reaction of the amines and hydroxyl components with the isocyanate-containing distillation residues is not bound to any order; it can also take place in stages. A particularly advantageous embodiment of the invention is that waste amines which are obtained within polyurethane chemistry in the synthesis of aniline, toluenediamine and diphenylmethanediamine in the form of precursors, distillation residues and rejection products are used as amines. The possibility of using amines as raw material for the preparation of the polyols according to the invention was surprising, since it is generally known that when reacting amines with isocyanates either highly viscous or crystalline reaction products are formed, which make a polyolic use of the reaction products impossible. For this reason, the recycling of amines was rejected in WP CO8G / 237275, WP CO8G / 237276 and WP CO8G / 250811 and proposed use of these substances only in the form of their rather expensive alkoxylation. However, it has been found that when partial replacement of the hydroxyl components by amines and subsequent reaction with isocyanate-containing distillation residues urethane-containing polyols are obtained with good suitability for polyurethane processing.

Particularly surprising is the fact that this waste incineration, which are incurred in the production of amine polyurethane raw materials and which were previously destroyed because of lack of uses on a large scale, can be recycled. The combination of the amine waste products with isocyanate-containing distillation residues results in a particularly favorable and environmentally friendly recycling of waste products of polyurethane chemistry as a result of the procedure according to the invention. Since the amines can be used without any modification in the polyol synthesis, the additional technological costs are extremely low. In addition, when aromatic amines are used, it is possible to prepare polyols having an increased proportion of aromatics with the same hydroxyl number.

embodiments example 1

In 717.3g of an unneutralized, alkaline polyether alcohol of hydroxyl number 850mg KOH / g 79.3 g Dioxohexahydrotriazin be registered and dissolved with stirring at 150 ⁰ C.

After cooling to 125 ° C, 200 g of a liquid residue of toluene diisocyanate distillation are added at this temperature. The stabilization of the polyol takes place after decayed exothermic reaction at 15O ⁰ C with an epoxidized soybean oil in an amount of 30g.

The polyol has the following analytical data:

Hydroxyl number: 510 mg KOH / g

Acid value: 1.6 mg KOH / g

Viscosity at 25 ⁰ C: 6180mPas

Example 2

To 150 g of a mixture consisting of 85.64% by weight of aniline, 12.63% by weight of cyclohexylamine and 1.73% by weight of cyclohexanol is added 1005 g of an alkaline polyether alcohol having a hydroxyl number of 850 mg KOH / g. At a temperature of 120 ⁰ C, 300 g of liquid distillation residue of toluene diisocyanate distillation is metered in with stirring; the stabilization of the polyol is carried out with 45 g of an epoxidized soybean oil

 The polyol has the following characteristics:

Hydroxyl number: 647 mg KOH / g

Acid value: 2.0 mg KOH / g

Viscosity at 25 ° C: 3600mPas

Example 3

To 77% of a mixture consisting of 10% aniline and 90% of the polyether used in Examples 1 and 2 are dosed at 120 ° C20% of a liquid residue of the toluene diisocyanate distillation. After the exothermic reaction has subsided, stabilization takes place with 3% of an epoxidized soybean oil. The polyol has the following characteristics:

Hydroxyl number: 655 mgKOH / g

Viscosity at 25 ⁰ C: 3100mPas

Example 4

160g of the polyether used in Examples 1 to .3 are mixed at 6O ⁰ C and 40g of a fatty amine having an average molecular weight of 300 and a proportion of primary amines of about 75%. After heating to 13O ⁰ C, 40 g of liquid distillation residue of toluene diisocyanate synthesis are metered in with stirring. Stabilization of the polyol takes place after the exothermic reaction has subsided with 8 g of an epoxidized soybean oil. The polyol has the following characteristics:

Hydroxyl number: 500mgKOH / g

Acid number: 0.5 mgKOH / g

Viscosity at 25 ⁰ C: öOOOmPas

Example 5

To a mixture of 70g of a product of the forward Toluylendiamindestillation and 630g of an alkaline Rohpolyetheralkohols the hydroxyl number 860 mg KOH / g are dosed at 11O ⁰ C, with stirring, 260g of a heavy product of the Toluylendiisocyanatsynthese.

Stabilization of the polyol obtained takes place after the exothermic reaction has subsided with 40 g of an epoxidized soybean oil.

The polyol has the following characteristics:

Hydroxyl number: 595 mg KOH / g

Acid value: 1.3 mg KOH / g

Viscosity at 25 ⁰ C: 8800mPas

Example 6

To a mixture consisting of 7% of a residue of Toluylendiaminsynthese and 93% of a neutral polyether alcohol having a hydroxyl number of 850 mg KOH / g are metered at 145 ° C with stirring 26% based on the mixture of a distillation residue of Toluylendiisocyanatsynthese.

After the exothermic reaction has subsided, the addition of 4% of an epoxidized soybean oil.

The black-brown product has the following key figures:

Hydroxyl number: 572 mg KOH / g

Acid value: 0.9 mg KOH / g

Viscosity at 25 ° C: 14,700 mPas

Example 7

In 800 parts of an alkaline polyether alcohol of hydroxyl number 600mg KOH / g are added at 70 ⁰ C 279 parts of aniline with stirring. At 12O ⁰ C, a slow metering of 631 g of a distillation residue of toluene diisocyanate is carried out. After the exothermic reaction has subsided, the addition of 60 g of an epoxidized oleic acid butyl ester.

The product has the following key figures:

Hydroxyl number: 237 mg KOH / g

Acid value: 0.6 mg KOH / g

Viscosity at 25 ⁰ C: 28000mPas

Example 8

In a stirred vessel, 1.51 hydroxyl 600mg KOH / g are heated at 120 ⁰ C 400 g of a polyether alcohol. At this temperature, with stirring, the metering of a residue of Toluylendiisocyanatdestillation in an amount of 166 g. After the exothermic reaction has subsided, 200 g of a Ausschleusungsproduktes the diphenylmethane-polyamine synthesis containing cyclohexanol, cyclohexylamine and aniline, added and the reaction mixture cooled to 100 ⁰ C, Under intimate mixing is carried out a further dosage of 232 g of distillation residue of Toluylendiisocyanatsynthese. After the exothermic reaction has subsided, the addition of 40 g of an epoxidized soybean oil. The product has the following characteristics:

Hydroxyl number: 159 mg KOH / g

Acid value: 0.5 mg KOH / g

Viscosity at 25 ⁰ C: 45 000mPas

Claims (3)

1. A process for the preparation of polyols with Urethanstrukturan isocyanate-containing distillation residues and hydroxyl components at temperatures <250 ° C, optionally using additives such as compounds with carbon chain η and epoxides, characterized in that the hydroxyl components are partially substituted by primary and / or secondary amines , 2. The method according to item 1, characterized in that as amines all NH-functional compounds having boiling points> 100 ⁰ C, preferably aniline and its condensation products, toluenediamines, cyclohexylamines, N-alkylamines, Dioxohexahydrotriazin, fatty amines and / or mixtures containing these amines contained, are used. 3. The method according to item 1, characterized in that the amines waste amines incurred within the polyurethane chemistry in the synthesis of aniline, diphenylmethanediamine and its homologues and toluene diamine in the form of heats, distillation residues and Ausschleusungsprodukten be used.