DD219030A3 - PROCESS FOR POLYMERIZING ORGANIC ISOCYANATES - Google Patents

Abstract

The invention describes novel catalysts for the polymerization of organic isocyanates to isocyanurate group-containing compounds. The new catalysts are substances that contain a tertiary amino group and a hemiacetal group R-O-CHR-OH in one molecule. These catalysts have an exceptionally high activity in the polymerization of organic to isocyanurate polyisocyanates, in the production of polyisocyanurate and in the introduction of isocyanurate groups in any polyurethane plastics.

Description

R ¹ (R) _n -N- [X-OCH

^{1 4} OH "

-2- 241886

Y-

 / IR) ,. \

(X-OCHR ¹ -O-H),

Z NX-OCHR ¹ -OH

IV

For the radicals indicated, the following groups can be attached:

R = alkyl, cycloalkyl, aralkyl

(R) ₂ = (-CH ₂ -J ₃ , (-CH ₂ -U, (-CH-I ₆

R ¹ = H, alkyl, aryl, heteroaryl

X = polyvalent radical of any aminoalcohol, for. B. -CH ₂ CH ₂ -, CH ₂ -CH-CH _3, -CH ₂ CH ₂ OCONHCH ₂ CH ₂ -, CH ₂ CH ₂ COOCH ₂ CH ₂ O-,

Y = polyvalent radical of a di- or polyamine, ζ. B. -CH ₂ -CH ₂ -, -CH ₂ CH ₂ OCH ₂ CH ₂ -, (-CH ₂ -) ₆ Z = S ₁ O ₁ NR, NX-OCHR ¹ OH

η = 0-2, m + η = 3

к = 0-2, к + 1 = 2, і = 2-6

Optionally, the radicals mentioned may still carry indifferent substituents or also have further catalytically or cocatalytically active substituents, such as. B. tert. Amino groups, urethane groups, alcohol groups, phenol groups, etc. Very particular preference is given to compounds derived from formaldehyde.

Below are some compounds to be exemplified:

2-Dimethylaminoethoxymethanol

N- (hydroxymethoxyethyl) -piperidine η

N, N'-bis (hydroxymethoxyethyl) -piperazine

N, N-bis (hydroxymethoxyethyl) aminopropionitrile

N, N-bis (hydroxymethoxyethyl) -N ', N'-dimethyl-propanediamine (1.3)

2-hydroxy-N-methyl-morpholine.

The preparation of the products according to the invention is carried out by the known methods of hemidetal acetalization of aldehydes (see Houben-Weyl, Methods of Organic Chemistry, Bd.6 / 3) and in particular from the corresponding alcohols and paraformaldehyde (DE-AS 1,092,002).

By using the catalysts according to the invention, it is possible to convert diisocyanates to isocyanurate polyisocyanates in a simple manner. The necessary catalyst concentration varies from case to case and is between about 0.01 and 2%. The targeted cyclotrimerization of diisocyanates to Isocyanuratpolyisocyanaten carried out according to other catalytic processes of the prior art solvent-free or in the presence of inert solvents at temperatures between 0 and 120 ⁰ C, preferably 20-80 ⁰ C, and reaction times between 0.1 and 20 h. After reaching the preferred conversion, the reaction by the addition of acidic substances such. B.

Benzoyl chloride, toluenesulfochloride, phosphoric acid, be terminated.

The products thus produced may optionally be used after removal of the residual amounts of free diisocyanates as hardener components for polyurethane coatings and adhesives.

After blocking the free NCO groups with phenols, oximes or lactams, valuable isocyanate releasers are available for oven coatings.

The solvent-free isocyanurate polyisocyanates are suitable for introducing isocyanurate groups into any polyurethane plastics, in particular in polyurethane foams.

Ein'weiteres field of application of the invention is the Hersteilung of optionally flame retardant, containing urethane groups Polyisocyanuratschaumstoffen by reacting organic polyisocyanates and polyhydroxy compounds in the presence of catalysts, blowing agents, adjuvants and additives, which 'is characterized in that the tert. Amino-containing hemiacetals are used. Usually, from 0.4 to 5.0 parts by weight of catalyst per 100 parts by weight of polyisocyanate are used.

Catalysts of urethane formation, such as diazabicyclooctane, 2,2-dimethyl-silamorpholine, I.S-diazabicyclo-undecene, tetramethylguanidine or organic metal compounds, such as tin octoate and dibutylzine dilaurate are to be optimally used.

The polyisocyanates, polyhydroxy compounds, blowing agents, foam stabilizers, flame retardants used correspond to the substances customary in polyurethane chemistry. The Hersteilung can also be done by the known methods of the prior art.

Example 1:

5 ml of phenyl isocyanate (distilled CW = 50 ppm) are dissolved in 50 ml of absulutem methyl ethyl ketone, tempered to 50 ⁰ C and treated with 53 mg dimethylaminoethoxymethanol. Samples are taken from the reaction solution after certain times, reacted with methanol and analyzed by high pressure liquid chromatography for their content of phenyl isocyanate (as N-phenyl-O-methylcarbamate, RT · 4.03) and triphenylisocyanurate (RT я S, 1 # i (Tab . 1).

Table 1

-z- 241 886

t / min

PhNCO / moir

(PhNCO) ₃ / mol

1 O 0.832 - 2 10 0.707 0,021 3 20 0.405 1,106 4 30 0,238 0.143 5 40 0.143 0.172

The dimethylaminoethoxymethanol used was prepared as follows:

89g dimethylaminoethanol are heated with stirring to 33g of paraformaldehyde to about 70 ⁰ C. After addition of 0.1 ml of 1N KOH, spontaneous depolymerization of the paraformaldehyde takes place. After cooling, it is filtered and the clear liquid consisting essentially of dimethylaminoethoxymethanol is used as the catalyst.

Example 2:

(Compared to DE-AS-1013869). Analogously to Example No. 1 are each dissolved in 5 ml of phenyl isocyanate and 100 ml of methyl ethyl ketone at 60 ⁰ Ca) with 0,121g dimethylaminoethanol (1,36mMol) and b) 0,162g Dimethylaminoethoxymethanol (1,36mMol) was added , and followed the NCO decrease by the titration method with dibutylamine. After 30 min, the NCO conversion is a) 3.7% for b) 77.6%, after 120 min for a) 13.7%, for b) 100%.

Example 3:

60 ml of toluene diisocyanate (80/20) are dissolved in 83 ml of butyl acetate, warmed to 6O ⁰ C and treated with the indicated amounts of the inventive catalysts 3 to 5. The vigorous reaction must be strongly cooled and is terminated after a few minutes by adding 0.4 ml of benzoyl chloride. The analytical data are given in Tab.2.

Examples β to 8:

The catatytic activity of the catalysts according to the invention is determined in the exothermic test. For this purpose, 10 ml of toluene diisocyanate (80/20) are reacted with 0.2 ml of the following compounds with stirring. The exothermic cyclotrimerization is monitored by measuring the temperature. Foaming occurring is estimated on the basis of the increase in volume (Table 3).

Table 2

Cyclotrimerization of toluene diisocyanate (80/20) in butyl acetate at 60 ⁰ C.

example Catalyst (ml) catalyst T / T 'max' * * * 93 reaction t (T _me Solid /% ATMt) _n , NCO /% TDI /% V / m time / min 3 2-dimethylamino- 2-diethyl 92 (5 min) 11 220 50 228 11.4 3.6 200 aminoethoxy 91 4 methanol 90 (8 minutes) 15 40 ¹¹ 8.7 2.9 2-dimethyl 160 236 230 5 ethoxymethanol (0,1) aminoethoxy 102 (13min) 94 20 40 ¹⁾ 8.3 3.2 2-diethylamino methanol 4-methyl- 135 276 130 ethoxy methanol (0.2) imino-bis Methylimino-bis (ethoxymetha- Induction T _met / ° C 76 ДТЛС ') / S "/ Grdmin" ¹ nol) period / s 63 (Max) (ethoxymethanol) (0,3) TDHT ²¹ 168 31 67 130 108 30 ¹¹ after dilution with butyl acetate TDMP ³¹ 126 53 20 Table 3 2-dimethyl - - - example aminoethanol 96 69 No. 6 69 70 7 35 52 8th 37 40 - 7 comparison Examples

1) 0.3 ml of a 20% solution in cyclohexane

2) 1; 3, & - tris-dimethylaminopropyl-hexahydro-triazine

3) 2,4,6-tris-dimethylaminomethyl-phenol

Claims (5)

1. A process for the polymerization of organic isocyanates in the presence of catalysts to isocyanurate and optionally carbodiimide-containing compounds, characterized in that compounds are used as catalysts which in a molecule both at least one tert. Have amino group as well as a hemiacetal group. -1-241 886 Invention claims: 2. The method according to item 1, characterized in that the catalysts tert-acetalization from tert. Amino-containing alcohols and formaldehyde are. 3. The method according to item 1 and 2, characterized in that the catalysts are Halbacetalisierungsprodukte of 2-dimethylaminoethanot, 2-dimethyl-aminopropanol, diethylaminoethanol and formaldehyde. 4. The method according to item 1-3, characterized in that the catalysts for the production of Polyisocyanuratschaumstoffen from organic polyisocyanates, polyhydroxy compounds, blowing agents, auxiliaries and additives are used. 5. The method according to item 1-3, characterized in that the catalysts are used for the preparation of optionally solvent-containing isocyanurate polyisocyanates. Process for the polymerization of organic isocyanates
Field of application of the invention The present invention relates to the preparation 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. Numerous catalysts for cyclization and polymerization are described in the present literature. As examples may be mentioned: 'strong bases, such as quaternary ammonium hydroxides, alkali metal salts of alcohols, phenols, amides and imides; furthermore alkali metal and metal salts of carboxylic acids, organometallic salts, phosphines, Mannich bases of phenols, substituted hexahydrotriazines and others. A large number of catalyst systems have been built on the basis of basic tertiary amines and suitable cocatalysts, for example tert. Amines in combination with oxiranes, aziridines, cyclic carbonates, lactones, hexahydro-s-triazines, a-diketones, aldehydes, oximes, alcohols, phenols, urethanes and allophanates. It is also possible to effect cyclization and polymerization reactions of isocyanates by acidic catalysts such as AICI ₃ , ZnCl ₂ , FeCl ₃ , BF ₃ and others. The anionic activation of isocyanurate formation by basic salts is generally quite effective, but with a number of limitations concerning the limited solubility of the salts in the reaction system, the sometimes extreme activity and the associated poor dosability and the susceptibility to impurities. Oils catalytic systems of tert. Amines and cocatalysts, especially epoxides are also particularly suitable. However, the often necessary pre-reaction between amine, cocatalyst and optionally also the isocyanate component often leads to complications that complicate the smooth flow of the reaction. By contrast, quaternary ammonium hydroxides prepared from amines, epoxides and H-acid compounds in a preliminary reaction are recommended, but suffer losses of activity during storage due to decomposition reactions, which in turn makes accurate metering problematical. High isocyanurate yields with simple reaction give the strongly basic N, N ', N "-Tris- (dialkylaminoalkyl) -1,3,5-hexahydrotriazine or Mannich bases of phenols, eg 2,4,6-tris (dimethylaminoethyl) phenol These classes of substances contain catalyst and cocatalyst in one molecule and correspond to the catalyst combinations tertiary amine / hexahydrotriazine or tertiary amine / phenol. The application of the latter catalysts belongs to the prior art, but also in many cases does not correspond to the technical and local requirements and circumstances in the production of polyurethane products containing isocyanurate groups. Object of the invention The object of the present invention was to find novel and readily available catalysts for the polymerization of isocyanates, which allow the production of Isocyanuratpolyisoyanaten and Polyisocyanuratschaumstoffen. 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 are in a molecule over at least one tert. Have amino group and a hemiacetal group. This combination leads to extraordinarily active catalysts for isocyanurate formation. The intramolecular effect is surprising, unknown in its mechanism, and unexpected from the prior art. Compared to comparable systems of the prior art z. As amine / alcohol, Phenolmannichbasen, tert. Amino-containing hexahydrotriazines and the non-coupling system amine / hemiacetal, the catalytic activity of the catalysts according to the invention in the polymerization of aromatic isocyanates is much higher. In addition, aliphatic and cycloaliphatic isocyanates can tri- and polymerize. Examples of the catalysts according to the invention preferably correspond to the constitutional formulas I-IV and are, for example, reaction products of dialkylaminoalkanols and aldehydes.