DE1159633B - Process for the production of homogeneous elastomers containing urethane groups - Google Patents

Description

Process for the production of homogeneous urethane groups Elastomers When using reaction mixtures of polyisocyanates and several compounds containing active hydrogen atoms, such as polyesters, polyester amides or polyethers, as casting resins, for molding or for the production of coatings. so for the production of homogeneous, non-foamed products, it was previously necessary to be heated to a greater or lesser extent for crosslinking or hardening.

Attempts have already been made to implement the reaction with the aid of catalysts to accelerate. Thus, in the German Auslegeschrift 1 034 850 certain organic Compounds of zinc, cadmium, titanium, antimony or bismuth, such as zinc adipate or triethyl antimony ester, ascribed a catalytic effect. The acceleration however, it is small, so that curing at room temperature is not possible. In German Patent 962 552 avoids the production of polyurethanes of side reactions in the presence of an acidic compound and a Non-basic metal compound soluble in at least one reaction component described. Here too, however, heating to 100 ° C. and above is necessary for hardening.

The invention relates to a process for the production of homogeneous, Elastomers containing urethane groups based on the conversion of polyisocyanates, polyethers and catalysts containing several OH groups with shaping the indicator that the reaction at room temperature in the presence of organotin (IV) compounds is carried out, these compounds at least one tin-sulfur or Contain tin-oxygen valence bond.

Organotin oxides, hydroxides, Organotin carboxylic acid esters and / or alcoholates used.

Dibutyltin diacetate, dibutyltin oxide, Dibutyltin dilaurate, dibutyltin di-2-ethylhexoate, dibutyltin oxide, dibutyltin monomethoxymethyl maleate, Dibutyltin sulfide, tributyltin 2-ethylhexoate, monobutyltin tri-2-ethylhexoate, triphenyltin hydroxide, Bis (tributyltin) oxide, bis (tributyltin) tetrapropenyl succinate, bis (tributyltin) n-nonyl succinate or bis (tributyltin) malonate proved.

In the Belgian patent 548 886 it is described that the drying of polyurethanes applied in dissolved form, among other things Addition of such tin compounds can be facilitated, but it is here already to preformed polyadducts that do not have any reactive isocyanate or Have more hydroxyl groups. According to the German patent specification 964 988 can regulate the pore size of foams based on polyester-polyisocyanate, if one in the implementation carboxylic acid salts or alcoholates of titanium, zirconium or Tin adds. However, this process has nothing to do with a catalysis as in the present one Case, but with the stabilization of the plastic film during foaming, especially the foaming of polyurethanes because of the low dissipation of the heat of reaction could already be carried out for a long time at room temperature.

The organotin compounds used according to the invention catalyze in general, the formation of the urethane bond. They also catalyze education of allophanates as well as of other reaction products of polyisocyanates with compounds containing active hydrogen atoms. The allophanate bonds are Cross bonds that cause the polyadducts to solidify or harden.

While networking can also be done by other means, e.g. B. by Addition of triols, or triisocyanates, can achieve the catalyzed formation from Allophanate cross-links a faster cure due to the catalysts of the invention come here.

The catalysts used according to the invention are already in very good shape effective in small amounts. An amount corresponding to 0.1 to 2% of tin is used on the weight of the reactants.

In the case of larger quantities, however, the plasticizing effect predominates Catalysts, so that amounts corresponding to 0.1 to 1 percent by weight of tin are preferred will.

The polyethers used have a molecular weight of about 750 to 4000, preferably between about 1000 to 2500.

These are polymers of cyclic ethers, such as. B. Ethylene oxide or 1,2-propylene oxide, or condensation products of glycols, such as ethylene glycol, propylene glycol, 1,2-butylene glycol, 1,4-butylene glycol or 2,3-butylene glycol, or polyadducts of glycols and cyclic ethers with one another.

The polyisocyanates used can be aliphatic or aromatic Be nature. Examples of aliphatic polyisocyanates are Äthylendii socyanat, Trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate or cyclohexane-1,4-diisocyanate. Examples of aromatic polyisocyanates are 2,4- and 2,6-tolylene diisocyanate, benzene-1,2,4-triisocyanate or diphenylmethane-4,4'-diisocyanate. The aromatic polyisocyanates are preferred.

In the liquid reaction mixtures of polyisocyanates and polyethers can - the ratio of - NCO groups to - OH groups between about 0.9: 1 and 1.8: 1.

Preferably, a reaction mixture of an aromatic polyisocyanate is used and a polyalkylene glycol ether reacted in which the isocyanate to hydroxyl groups are present in a ratio of about 1: 1 to 1.5: 1.0.

An excess of - NCO groups can temporarily plasticize the product; However, such an excess of isocyanate is optionally caused by secondary reactions used up under the influence of the catalyst. In the polyglycol portion of the reaction mixture may optionally contain some -N H bonds and others containing active hydrogen Ties to be included. At times, such ties are required to be special To achieve properties of the end product. Fillers can be found in large quantities use. Castings were made containing up to 95 percent by weight of filler exhibited.

Although the catalytic effectiveness of the catalysts according to of the invention usually increases with increasing temperature, is a heating of the Reaction mixture not required and not according to the invention. The hardening takes place so quickly at room temperature that the moldings are already after 5 to 30 minutes can be taken out of the mold and their final properties after 4 bis Have accepted 24 hours.

When carrying out the process according to the invention, one uses a reaction mixture consisting of two parts, one part as usual the polyether resin and the other part comprises the organic polyisocyanate. The Catalyst can be added before or after mixing. The selection of each The catalyst used depends on its solubility. Generally recommends it is the catalyst before mixing the polyether part of the reaction mixture incorporated, since a mixture of the catalyst is stored for a longer period of time and the polyisocyanate, a reduction in the utility of the polyisocyanate can occur.

Room temperature curing enables new areas of application for solid polyurethane synthetic resins.

The wide variety of uses of those used in accordance with the invention Products made from catalysts ranges from filled compositions to Weighting of plastic casings or other hollow bodies over molded bodies, tough, flexible cement block facings or masonry seals up to hard, abrasion-resistant, horn-like products.

The invention is illustrated by the following examples.

In the examples, "Part A" means the polyalkylene glycol ether component. It is a mixture of polypropylene glycols with molecular weights of 1025 and 2025, which has an average molecular weight of about 1,360.

The »Part Be is the reaction product of about 10 parts by weight of trimethylolpropane and 100 parts by weight of tolylene diisocyanate, mixed at about 400 C and heated to about 130 ° C for several hours. The resulting Product is a clear, yellow and mobile liquid with a specific Weight of about 1.24.

The acceleration of the reactivity between - NCO and --OH groups the formation of urethane bonds was determined as follows: They became the same Volumes of a 4. 10-4 molar solution of p-nitrophenyl isocyanate in isooctane as well a 2-10-3 molar solution of n-butanol in isooctane, the dibutyltin di (2-ethylhexoate) received in a molar concentration of 2 to 10-4, put together. It lay suggest a hydroxyl isocyanate ratio of about 5: 1.

Urethane formation was followed with a UV spectrophotometer. The results are given in Table A, the information on the amount of urethane to the percentage of converted - NCO at the end of the specified Relate time periods (in minutes).

Table A. Urethane (%) ........... 35 57 70 79 85 88 91 93 95 97 Time (minutes) ............ 10 20 30 40 50 60 70 80 90 100 Control solutions according to the preceding information, but without a catalyst, showed practically no urethane formation in the course of a reaction time of 100 minutes.

Accelerating the reaction between - NCO and NH groups too Allophanate linkages were determined as follows: p-nitrophenyl isocyanate was in the presence of the catalyst previously given in this example with n-butylphenyl carbamate brought to implementation.

The reactants were mixed in a dioxane solution and were present in a - NH- to NCO ratio of 25: 1.

The same results as in Table A were obtained.

Experiments with varying amounts of catalyst were carried out using dioxane solutions of n-butanol and p-nitrophenyl isocyanate in equimolar amounts. In each case, the amount of isocyanate converted after 50 minutes was determined in%. The amount of catalyst is given in mol percent based on the original amount of - NCO: Table B Urethane (%) ................ 10 20 30 40 50 60 70 80 90 Amount of catalyst ......... 0.5 0.7 1.9 3.4 6 9 14.5 22.5 52.5 It can be seen from Table B that even low concentrations of catalyst are extremely effective and that the increase in the acceleration with respect to the increase in the amount of catalyst becomes less at high catalyst concentrations.

The same observations were made in the manufacture of polyether urethanes made.

Example 1 From reaction mixtures with an - NCO - z - OH ratio of around 1.1: 1.0, polyurethanes were produced in filled and unfilled systems: I. 50 g Part A, 10.6 g Part B, II. 50 g Part A, 60 g filler made of clay and triple earth (50:50), 10.6 g part B.

Each reaction mixture became different as the mixture was prepared Amounts of dibutyltin dilaurate given as a catalyst and the effective wedge of the Catalyst in various concentrations as a function of heat rise of the reaction mixture recorded in a time of 5 minutes.

The reaction mixtures were mixed in paper cups and the in the temperature rise occurring in the beakers was recorded. The results are listed in Table C showing the amount of catalyst in terms of weight percent Tin, based on the total reactants (including the filler), reproduces.

Table C. Tin heat rise (° C) (Percent by weight) I II 0.06 19 11 0.14 22 15 0.34 24 16 0.46 25 17 1.21 28 - 1.84 31 - Here, too, the increase in the catalytic effectiveness at a high catalyst concentration no longer corresponds to the increase in the amount of catalyst. As expected, the temperature rise in the filled system is less than in the unfilled system.

As it occurs when using these catalysts in higher concentrations found to have a plasticizing influence, became one Number of standard reaction mixtures with varying amounts of catalyst according to Prepared Table D, in which the quantities of all ingredients are given in grams. The catalyst was dibutyl tin dilaurate. A filled system was used the filler again being a mixture of clay and triple earth (50:50).

Table D. Sample Catalyst Part A Part B Fillers 1 1.04 103 21 124 2 1.38 103 21 124 3 1.73 103 21 124 4 2.30 103 21 124 5 4.6 103 21 124 6 5.75 103 21 124 7 6.9 103 21 124 After mixing, each reaction mixture was poured into an open metal bowl and allowed to harden therein at room temperature. The time required for each sample to reach a reading of about 40 on the Shore A2 durometer was measured. The results are shown in Table E, in which the amount of catalyst is given in relation to percent by weight of tin, based on the total reactants (excluding the filler).

Table E. Sample tin time (minutes) 1 0.15% 114 2 0.21% 85 3 0.280! O 88 4 0.370 / o 60 5 0.75 0 / o 47 6 0.94 0.55 7 1.13% 57 With an amount of catalyst corresponding to more than 0.75 percent by weight of tin, the time required to achieve the hardness meter reading of 40 begins to increase, which indicates a plasticizing effect of larger amounts of catalyst.

Example 2 Using an identical reaction mixture, were tested various organotin compounds for their effectiveness. The composition of the reaction mixture was as follows: 264 g Part A, 56 g Part B, 1 g tin (as an organotin compound).

So each reaction mixture contained - based on the total weight the reactant - about 0.3% tin and had an isocyanate to hydroxyl ratio of about 1.15: 1.0.

The tin catalyst was used in the preparation of the reaction mixtures introduced into part A and dissolved in it before parts A and B are mixed or dispersed.

The reaction mixtures were mixed by hand and then mixed at room temperature (about 25 ° C) poured into a flat steel bowl in which the liquid mixture froze. All reaction mixtures solidified and were able to come out of the bowl after about one hour, with the exception of the control samples, one of which contained no catalyst and two contained a tertiary amine catalyst.

After the samples had stood at room temperature for 20 hours (counting from the time they were poured into the bowls), they were tested with a durometer. They were then kept at 65 ° C. for a further 20 hours and checked again with the durometer to determine whether there had been any change in the hardness of the samples. The results are shown in Table F: Table F Durometer value (Depth of impression according to Shore A2) Catalyst after 20 additional hours at room 20 hours temperature at 650 C Comparative sample without Catalyst ................... liquid liquid n-dibutyltin dilaurate ......... 26 27 n-Dibutyltin-di - (- 2-ethyl- hexoate ................... 24 1 26 n-tributyltin 2-ethylhexoate ... 24 24 n-Butyltin tri - (- 2-ethylhexoate) .. 17 21 Triphenyltin Hydroxide ........ 23 23 Bis-tributyltin) oxide ........ 23 23 Triethylamine * ............... liquid 16 N-methylmorpholine * ........ liquid 14 ** * About 3 percent by weight, based on the total amount the respondent. ** After 48 hours.

The products made using the organotin compounds were flexible elastomers with good moisture behavior and low lead bender Deformation. The color of the products corresponded to cloudy, translucent to clearly transparent Amber. The deviations in durometer readings as seen in Table F. of the samples among themselves were apparently due to minor differences in the Mixing and pouring processes caused as these stages were done by hand. These deviations do not apply to mechanical mixing.

As can be seen from Table F, the final ones were physical Properties of the samples achieved after curing for 20 hours at room temperature, whereby no significant changes after an additional cure of 20 hours at 65 ° C occurred.

The comparison sample without catalyst remained during the entire duration of the experiment fluid. The amines were ineffective at room temperature, albeit by a considerable amount higher concentrations than the tin catalysts used, the too had products manufactured using them that result from curing under the action of heat did not show their final properties even after 20 hours at 65 ° C achieved.

Example 3 In order to determine the influence of changing polyisocyanate-hydroxyl ratios on the effectiveness of the catalysts according to the invention, several elastomers were prepared and the time for the final cure was determined. The first of these reaction mixtures contained 264 parts by weight of Part A and 1 part of dibutyltin laurate, the parts by weight of Part B being varied. The results are shown in Table G: Table G Durometer value (Shore A2) Additional Part B NCO: OH hours at hours at Room temperature 650 C 3 l 21 22 l 43 45 0.9: 1.0 0 1 1 1 50 1.0: 1.0 7 14 13 13 55 l, l: l, o 22: 34 35 34 60 1.2: 1.0 20 30 36. 36 65 1.3: 1.0 8 19 33 36 70 1.4: 1.0 1 9 27 32 From Table C it can be seen that the fastest cure is achieved at an isocyanate to hydroxyl ratio of about 1.1: 1.0.

Same results were obtained with 199 parts of an implementation of Glycerine and propylene oxide obtained polyether with the average molecular weight of about 2700, 1 part dibutyltin laurate and various amounts of part B obtained.

Example 4 A number of rubber-like molded articles were made made with durometer readings ranging from about 20 to 35. This is a ideal area for roller surfaces of printing presses.

The reaction mixtures used were mixtures of Part A and B in such Combination that an isocyanate-hydroxyl ratio of 1.15: 1.0 was used, where part A was mixed with 20 / o catalyst before mixing. The catalysts and the present Percentage by weight of tin, based on the total amount the reactants were bis (tributyltin) tetrapropylene succinate (0.46%), Bis (tributyltin) carbonate (0.61%), bis (tributyltin) malonate (0.57%) and Bis - (tributyltin) - n - nonyl succinate (0.48 o / o).

The products were all out of the mold within an hour and reached their final hardness within 20 hours the removal from the mold. Using dibutyltin sulfide as a catalyst a rubber with a durometer reading of about 40 was formed.

Example 5 A hollow plastic tape dispenser weighing 108 g was obtained by pouring one of 92.5 g of Part A, about 2 g of dibutyltin dilaurate, 7.5 g of Part B, (- NCO to - OH ratio about 1.15: 1.0) and about 1000 g of metal lumps produced mixture weighted into the open bottom of the hollow plastic container. The dispenser was then placed upright on a polytetrafluoroethylene plate with a criss-cross pattern hatched surface on which the filled polyurethane hardened.

The solidification took place within about 2 hours at room temperature, whereupon the hardened polymer with the inner walls of the tape dispenser and the metal lumps was inextricably linked. This weighting gave the dispenser such a weight Impact resistance that it remains even after repeated drops on a hard surface did not break or splinter from a height of about four feet. The exposed one Polymer that forms the patterned lower surface of the dispenser serves as the non-slip surface.

Example 6 A number of elastomeric sealing, molded articles, firmly adhering coatings and concrete veneers became from a reaction mixture of 91.5 g of Part A, 8 g of Part B and 0.5 g of dibutyltin monomethoxymonomethyl maleate manufactured, with PartA up to 50% by weight of its weight of various Fillers were incorporated. These fillers included various Diatomaceous earth, nut shell meal, wood meal, sea shell meal, magnesium oxide or silicates.

The polyurethanes produced according to the invention can be found on many application areas not specifically listed here, such as electrical Embedding compounds, rocket fuel binders, flexible linings for molds and as a binder for on-the-spot hardening fillers for cavity wall components.

Claims (2)

PATENT CLAIMS: 1. Process for the production of homogeneous urethane groups containing elastomers based on the conversion of polyisocyanates, several Polyethers and catalysts containing OH groups with shaping, characterized in that that the reaction takes place at room temperature in the presence of organotin (IV) compounds is carried out, these compounds at least one tin-sulfur or Contain tin-oxygen valence bond. 2. The method according to claim 1, characterized in that the organotin compounds Organotin oxides, hydroxides, organotin carboxylic acid esters and / or alcoholates are used will. Considered publications: German Patent Specifications No. 962 555, 964 988; German interpretative document No. 1 034 850; Belgian patent specification No. 548 886.