DD236742A1 - PROCESS FOR POLYMERIZATION OF ISOCYANATES (II) - Google Patents

Abstract

The invention describes catalysts for the polymerization of organic isocyanates to isocyanurate group-containing compounds. The new catalysts are substances which contain in one molecule tertiary amino groups and at least one Dialkylaminomethylamidgruppe R2N-CH2-N-CO-R2N-CH2-. These catalysts have a high activity in the polymerization of isocyanates to Isocyanuratpolyisocyanaten, in the production of Polyisocyanuratschaum and in the introduction of isocyanurate groups in other polyurethane plastics.

Description

-2- 618

Object of the invention

Object of the present invention wares to find novel and readily available catalysts for the polymerization of isocyanates, which allow the preparation of isocyanurate and optionally Carbodiimidgruppen having polymerization.

Explanation of the essence of the invention

The present invention is the preparation and use of novel catalysts for the polymerization of organic isocyanates.

The novel catalysts are characterized in that they have in one molecule at least one tertiary amino group and a Dialkylaminomethylamidgruppe. This combination leads to extraordinarily active catalysts of isocyanurate formation. The intramolecular effect is surprising and was unexpected due to knowledge of the catalytic polymerization of isocyanates. Compared to comparable non-salt catalysts of the prior art, as. As aminoalcohol, Phenolmannichbasen, subst. Hexahydrotriazinen and the uncoupled system tert. Amine / amide Mannich base, the catalytic activity of the substances according to the invention is significantly higher, in particular in the polymerization of aromatic isocyanates. In addition, other isocyanates can tri- or polymerize. At elevated temperature, the formation of carbodiimide groups and their reaction products is simultaneously effected to some extent.

Examples of the catalysts according to the invention preferably correspond to the general formulas I-III and represent, for example, reaction products of amines, aldehydes and amides, urethanes, ureas, lactams, imides or corresponding heterocycles.

Rf-fAj-NR'-CHR'-NR ^ CO-R ⁴ I

RiN- (A) -N (CO-R ⁴ I-CH R ¹ -N Ri * II

R | - (A) -CO-NR ³ -CHR ¹ -NR | III

The radical carrying the tertiary amino group can be in the aminoalkyl part (I), in the amide part (II), in the carboxylic acid part (III) or simultaneously in different parts. The position of the tertiary amino group and its structure significantly influences the catalytic activity of the substances according to the invention, so that different efficiencies can be set.

The following groups are to be used by way of example for the radicals indicated:

A = - (CHR ¹ ) _n -, - (CHR ¹ ) _n -X- (CHR ¹ ) -,

R ¹ = H, alkyl, aryl, dialkylaminoalkyl,

R ² = alkyl, cycloalkyl, aralkyl

R ² , R ² = linked radicals such as - (CH ₂ J _n , -, CH ₂ CH ₂ XCH ₂ CH ₂

R ³ = R ¹ , CO-R ⁴

R ⁴ = H, alkyl, aryl, alkoxy

R ³ , R ⁴ = linked radicals, such as - (CH ₂ ) _m -, (CH ₂ ) _m -X-

X = 0.5, NR '

η = 2-20,

m = 2-5.

The carboxylic acid group may be replaced by the corresponding structures of sulfur or phosphorus containing acids.

Likewise, it is possible that inventive catalysts are derived from corresponding heterocycles, such as. B. of barbituric acid, hydrantoin, cyanuric acid or melamine derivatives. Optionally, the said groups may still carry indifferent substituents or also have further catalytically or co-catalytically active substituents, such as. B. tert.

Amino groups, urethane groups, alcohol groups, phenolic groups and others.

Particularly preferred are compounds derived from formaldehyde.

Below are some compounds to be exemplified:

N-iDimethylaminomethyO-O-ldimethylaminoethyO carbamate,

N-bis (dimethylaminopropyl) aminomethyl-N-methylformamide,

N-Dimethylaminomethy-N-dimethylaminopropyl-formamide,

N- (dimethylaminomethyl) -dimethylaminoethoxypropionamid,

N-fDimethylaminomethyO-e-dimethylaminocapronamid,

N-fDimethylaminopropylJn-ldimethylaminomethyll-O-fdimethylamino-methoxyethylJ carbamate.

The catalysts of the invention are readily available by literature methods for the preparation of aminomethylamides. Special information can be found for example in:

Houben-Weyl, Methoden der Org. Chemie, Vol. 11/2 and 14/2

H. Helmann, G.Opitz, Diea-Aminoalkylation, Weinheim 1960

E. Müller, H. Thomas, Angew. Makromol. Chem. 1973, 34, 1111

M.Tramontini, Synthesis 1973, 373

The catalysts of the invention are predominantly liquid substances whose low molecular weight representatives can be purified by high vacuum distillation and characterized by elemental analysis, refractive index, spectroscopic methods or determination of the amine equivalent. The compounds are to some extent thermally stable and storable. The largest part of the compounds according to the invention was previously unknown and was first produced.

By using the catalysts according to the invention, diisocyanates can be converted in a simple manner into industrially interesting isocyanurate polyisocyanates.

-3- 618 63

The targeted cyclotrimerization of diisocyanates to isocyanurate polyisocyanates is carried out according to other catalytic processes of the prior art solvent-free or in the presence of inert solvents at temperatures between Ound 120 ° C, preferably at 20-80 ° C, and reaction times between 0.1 and 20 h. The necessary catalyst concentration varies from case to case and is between about 0.01 and 2.0%. After reaching the preferred conversion, the reaction by addition of acidic substances such as benzoyl chloride, toluenesulfonyl chloride, phosphoric acid, HCl, etc., be terminated. The products thus prepared can be used as physiologically acceptable hardener components for polyurethane coatings and adhesives after the removal of the residual amounts of free diisocyanates, if appropriate. By reaction with suitable little branched polyols Einkomponentenlacke for wood and building protection are available. After blocking the free NCO groups with phenols, lactams, oximes and similar agents, valuable isocyanate releasers are available for wire and fabric coatings and other special fields of application. Solvent-free solutions of isocyanurate polyisocyanates in excess diisocyanates are suitable for introducing thermally stable isocyanurate groups into any polyurethane plastics, in particular in polyurethane foams. Another field of application of the invention is the preparation of optionally flame-retardant urethane-containing polyisocyanurate foams by reacting organic isocyanates and polyhydroxy compounds in the presence of catalysts, blowing agents, auxiliaries and additives, characterized in that the substances according to the invention are used as catalysts. The foams produced in this way simultaneously have an increased content of carbodiimide groups and their reaction products. Usually, 0.4-5.0% of catalyst are used, optionally in combination with other polymerization catalysts. The polyisocyanates, polyhydroxyl compounds, blowing agents, foam stabilizers, flame retardants used correspond to the substances customary in polyurethane chemistry. The preparation can be carried out according to the known methods of the prior art.

embodiments Preparation of catalysts according to the invention

A) 169 g of O-dimethylaminoethyl carbamate are dissolved in 200 ml of benzene and treated with 48 g of paraformaldehyde and 265 g of 32% dimethylamine solution. By azeotropic distillation, the water contained is removed and is obtained after distilling off the solvent 206 g (86% yield) of a colorless oily liquid. The purification by vacuum distillation produces a colorless product with the following data:

Bp ₁₀ : 139-142 ⁰ C ng ⁰ : 1.4586 Yield: 135 g (56%)

Elemental analysis: gef. ber./%

C 52.38 52.45

H 7,28 7,15

N 12,83 22,94

Structure: Me ₂ NCH ₂ NHCOOCH ₂ CH ₂ NMe ₂ (28/4)

In an analogous manner, the following compounds are prepared and characterized as undistilled products (ng ⁰ ):

B) Me ₂ NCH ₂ CH ₂ CO-NH-CH ₂ NMe ₂ (28/1),

C) Me ₂ NCH ₂ CH ₂ CH ₂ N (CH ₂ NHCOOCH ₂ CH ₃ ) (28/6), 1.4635

D) Bu (CH ₂ NHCOOCH ₂ CH ₂ NMe ₂ ) ₂ (28/8), 1.4689

^E) O ^ ^ 2TCH ₂ HHCOOGH ₂ CH ₂ IMe ₂ (28 / n), i, 4730

F) N (CH ₂ NHCOOCH ₂ CH ₂ NMe ₂ ) S (28/13), 1.4664

G) Me (CH ₂ NHCOOCH ₂ CH ₂ NMe ₂ J ₂ (28/15), 1.4695 H) Me ₂ NCH ₂ CH ₂ CH ₂ N (CHO) -CH ₂ NMe ₂ (28/19), 1, 4678 I) (Me ₂ NCH ₂ CH ₂ CH ₂ ) ₂ N-CH ₂ N (CH ₃ ) -CHO (28/24), 1.4753 K) Pr ₂ NCH ₂ NHCOOCH ₂ CH ₂ NMe ₂ (28/251 , 1.4619 L) Me ₂ NCH ₂ CH ₂ CH ₂ N (CH ₂ NHCOOCH ₂ CH ₂ NMe ₂ J ₂ (28/26), 1.4745

M) Me ₂ NCH ₂ CH ₂ CH ₂ N (CH ₂ NMe ₂ ) -CqOCH ₂ CH ₂ OCH ₂ NMe ₂ (28/29), 1.4630. _/: * *

example 1

5.0 ml of phenyl isocyanate (distilled, CIhy = 83ppm) !, are dissolved in 50 ml of dry methyl ethyl ketone, heated to 5O ⁰ C and treated with 1.0 ml of N- (dimethylaminomethyl) -O- (dimethylaminoethyl) carbamate (28/4) was added. From the reaction solution samples are taken after certain times, reacted with methanol and analyzed by high pressure liquid chromatography for their content of phenyl isocyanate (as N-phenyl-O-methyl-carbamate, RT = 4.08) and triphenylisocyanurate (RT = 5.20) ( Table 1).

table

PhNCO / moir ¹

(PhNCO) ₃ / moir

0.832 0.675 0.521 0.401 0.307 0.207 0.154 0.123

0.052 0.077 0.117 0.136 0.145 0.157 0.169

Example 2

60 ml of toluylene diisocyanate (80/20) are dissolved in 86 ml of butyl acetate, heated to 60 ° C., and 0.2 ml of N- (diisopropylaminomethyl) -0- (dimethylaminoethyl) carbamate (28/25) are added. It is necessary to cool and terminate the reaction with 0.5 ml of benzoyl chloride when the desired NCO content is reached. The polyisocyanurate polyisocyanate solutions are characterized by NCO content, TDI content and viscosity.

Reaction time: 200 min NCO: 12.5% η (20 X): 25MPa-s TDI: 3.9%

Examples 3-13 To determine the catalytic activity for the polymerization of isocyanates, 0.2 ml of the stated catalysts are mixed with 10 ml of 2,4 / 2,6-toluene diisocyanate (systanate TP80) under magnetic stirring in an insulated vessel. The exothermic reaction is monitored by temperature measurement (thermocouple) and the characteristic variables of the temperature profile used for comparative evaluation. As examples of the prior art, DMF (tris-2,4,6-dimethylaminomethyl-phenol) and Polycat 41 (tris-1,3,5-dimethylaminopropyl-hexahydrotriazine) are included.

Table 2 example Catalyst / Nr. Ind-period / s T _m ax / ° C 3 4.28 28 74 4 6.28 28 81.5 5 8.28 83 104 6 11.28 62 95 - 7 28/13 27 128.5 8th 28/15 27 126.5 9 28/19 295 74.5 10 28/24 34 93.5 11 28/25 57 103 12 28/29 93 130.5 13 1.28 no cyclotrimerization (16 ' 'C / 5 min) Comparative Examples DMP30 244 40 Polycat 41 16 86

Claims (4)

1. A process for the polymerization of organic isocyanates to isocyanurate and optionally carbodiimide-containing compounds, characterized in that compounds are used as catalysts; in a molecule via at least one basic tertiary amino group as well as via an aminomethyl group of the structure -CX-N-CH ₂ -NR ₂ feature. -1- 618 63 Invention claims: 2. The method according to claim 1, characterized in that the catalysts are dialkylaminomethylamide derivatives of the following structure: a) aminomethylamide derivatives of tert. Amino-containing polyamines, R | N- (A) -NR ¹ -CH ₂ -NR ³ -CO-R ⁴ b) aminoethylamide derivatives of dialkylaminoalkylamides, ureas, urethanes, etc. R 1 N- (A) -N (CO-R ⁴ I-CH ₂ N Ri c) Aminoethylamide derivatives of dialkylaminocarboxylic acids
R | N- (A) -CO-NR ³ -CH ₂ NR | wherein R ¹ , R ^{2 are} preferably alkyl, R ³ , R ^{4 are} preferably H, alkyl, cycloalkyl, aryl or together form a teterocyclic radical and are the same as (CH ₂ ) _n -, - (CHMe) _n ) -, - (CH ₂ ) _n - X- (CH ₂ ) _n - (X = O, S, NR ¹ , n = 2-10). 3. The method according to claim 1 and 2, characterized in that the catalysts are used for the preparation of Isocyanuratpolyisocyanatlösungen. 4. The method according to claim 1 and 2, characterized in that the catalysts are used for the production of polyisocyanurate and / or polyurethane foams. Field of application of the invention The present invention relates to the preparation and use of novel catalysts and their use for the polymerization of isocyanates to isocyanurate groups and optionally carbodiimide-containing polyisocyanates, Polyisocyanuratschaumstoffen and other polyurethane plastics. Characteristic of the known technical solutions It is known that isocyanates can be converted into isocyanurates with the aid of catalysts. The prior art describes numerous catalysts for the cyclization and polymerization of isocyanates. Examples include: strong bases such as quaternary ammonium hydroxides, alkoxides, phenates, carboxylates, alkali metal salts of alcohols, phenols, amides, imides and lactams, alkali metal and metal salts of carboxylic acids, organometallic salts, phosphines, substituted hexahydrotriazines, Phenolmannich bases and others , A large number of catalyst systems have been built on the basis of basic tertiary amines and suitable cocatalysts, for example with tert. Amines and oxiranes, aziridines, cyclic carbonates, lactones, hexahydrotriazines, α-diketones, aldehydes, oximes, alcohols, phenols, urethanes and allophanates. In this case, zwitterionic intermediates are often the active compounds, which can also be used directly as such. It is also possible to promote cyclization and polymerization reactions of isocyanates by acid catalysts such as AICI ₃ , ZnCl ₂ , BF ₃ and others. The anionic activation of isocyanurate formation by basic salts is generally quite effective, but with a number of limitations, which affect the limited solubility of the salts in the reaction system, which often extreme activity and the associated poor dosability and susceptibility to contamination. Catalysts of tertiary amines and cocatalysts, especially epoxides, are also particularly suitable, with the preferred use of diozabicyclooctane to provide sufficient activity and incorporation of excess epoxide to form oxazolidone structures. Furthermore, quaternary ammonium compounds prepared from amines, epoxides and H-acidic compounds in a pre-reaction have been recommended. However, they suffer during storage by decomposition reactions loss of activity, which in turn makes accurate dosing problematic. High isocyanur yields with simple reaction give the strongly basic N, N ', N "-tris- (dialkylaminoalkyl) -1,3,5-hexahydrotrizines or Mannich bases of phenols, eg 2,4,6-tris- (dimethylaminomethyl) These classes of compounds contain catalyst and cocatalyst in one molecule and, in combination with certain alcohols or s-triazines, these catalysts are also used in the production of carbodiimide-containing foams which were previously only accessible via special phospholeoxides Carbodiimide groups are often very desirable because of the associated increase in flame retardance and temperature resistance.The use of the listed catalysts belongs to the prior art, but in many cases does not correspond to the technical, local or raw material-side conditions in the preparation of isocyanurate and optionally carbodiimide-containing polyurethane products.