PROCESS FOR PRODUCING POLYURETHANES USING BIS-(4- AMINO-2- HALOGENO-3, 5-DIALKYLPHENYL) -METHANE AND ARTICLES PREPARED THEREFROM

Abstract: In a process for producing polyurethanes by reacting a) di- and/or polyisocyanate, and b) di- and/or polyhydric alcohol in the presence of at least one metal compound as a catalyst, there is added to the reaction mixture at least one bis-(4-amino-2-halogeno-3,5-dialkylphenyl)-methane of general formula (I): wherein Hal denotes C1 or Br and R1 to R4 are the same or different and each denote an alkyl groupe having 1 to 4 carbon atoms, and at least one metallo-organic compound is used as the catalyst. An article produced therefrom contains bound residues of the foregoing formula.

Description: PROCESS FOR PRODUCING POLYURETHANES USING BIS-(4- AMINO-2- HALOGENO-3, 5-DIALKYLPHENYL) -METHANE AND ARTICLES PREPARED THEREFROM Usually polyurethane casting materials, for example for embedding medical articles, m particular membranes, comprise three mam components, more specifically di- and/or polyisocyanate. di- and/or Dolyhydπc alcohol as well as a catalyst or accelerator The di- and/or polyisocyanate used is for 5 example diphenylmethane dnsocyanate. toluylene dnsccyanate and their prepolyers or hexamethylene dnsocyanate. dicyclohexylmethane dnsocyanate. isophorone dnsocyanate and their prepolymers Tne polyhydπc alcohols that are considered are for example polyether polyhydπc alcohols or polyester polyhydπc alcohols and in particular in the medical area of use also castor 10 oil Normal catalysts for the production of polyurethanes are those based on tin. mercury, lead, bismuth, iron or acid-based catalysts When embedding memDrane materials, in particular for medical engineering. the use of conventional polyurethane-based casting materials requires ^ter complicated and expensive drying procedures which either necessitate long 15 drying times or are highly cost-intensive. Those expensive drying procedures are required in order to achieve a bubble-free or foam-free casting. Therefore the object of the present invention is to provide a process for producing polyurethanes, m particular for embedding articles in medical engineering, wherein a drying operation for the articles to be embedded such 20 as hollow fibre membrane bunches can be substantially eliminated or the drying measures can be greatly reduced. That object is attained in accordance with the invention For that purpose, a process for producing polyurethanes by reaction of a) di- and/or polyisocyanate. and 25 b) di- and/or polyhydπc alcohol in the presence of at least one metal compound as a catalyst is characterised in that there is added to the reaction mixture at least one bιs-(4-amιno-2- halogeno-3.5-dιalkylphenyl) -methane of the general formula. 30 35 wherein Hal means_Cl or Br and R λ to R 4 are the same or different and each denote an alkyl group having 1 to 4 carbon atoms, and at least one metal lo- orgamc compound is used as the catalyst. These two types of compounds afford a surprising synergistic effect as the 40 bιs-(4-amιno-2-halogeno-3.5-dιalkylpheπyl) -methane alone does not afford satisfactory results, m particular for the sector of medical engineering The addition of that compound in amounts of at least 3% by weight admittedly results in avoiding the formation of foam and bubbles or blowholes for example when casting water-bearing membranes but in that case white and porous end products are the result, which in most cases are not acceptable, and hardening either takes place very slowly over hours with the addition of a few percent of that compound and relatively quickly only when adding relatively large amounts such as about 20 % by weight The products achieved in that way are not acceptable as embedding materials in regard to medical engineering as they are porous and do not enjoy adequate adhesion for example to the dialyser housing and the hollow fibre membranes to be embedded The combination with special catalysts, namely metal lo-orgamc compounds, means however that the reaction mixture no longer becomes cloudy but remains transparent and enjoys good mechanical properties such as good adhesion to articles such as hollow fibre membranes, dialyser housings and so forth The amount of catalyst to be added depends on the added amount of bis-(4- aππno-2-halogeno-3,5-dιalkylphenyl) -methane and can easily be optimised by the average man skilled in the art on the basis of the foregoing technical teaching, by carrying out a few serial tests Upon an increase in the amount of catalyst, for example in order to increase the reaction speed, slight bubble or blowhole formation can occur in the polyurethane due to moisture of the articles to be embedded, but the extent of such bubble or blowhole formation is much lesser than foam formation when using commercially available polyurethane resins Bubble or blowhole formation in the case of the process according to the invention usually occurs at most along the wet hollow fibre membranes which are to be embedded, without bubble or blowhole formation encroaching onto the remaining resin mixture If such a slight degree of bubble or blowhole formation is also undesired, it is preferable for the catalyst to be added only in such an amount that clouding of the reaction mixture just disappears or the reaction mixture j ust goes clear In accordance with the invention, with a suitable choice of the catalyst and the amount of catalyst added, it is possible for even wet hollow fibre membranes to be embedded in an absolutely bubble-free condition As the amount of catalyst cannot be increased ust as may be desired, the reaction speed can be increased by the addition of an increased amount of bιs-(4-amιno- 2-halogeno-3,5-dι alkylphenyl) -methane, with simultaneous adaptation of the concentration of catalyst The added amount of bιs- ( 4-amιno-2-halogeno-3.5-dιalkylphenyl)-methane is desirably in the range of from 3 to 20 % by weight, preferably in the range of from 5 to 10 % by weight, with respect to the total weight of the components a ) + b). With an addition of the order of magnitude of about 5 % by weight upwards, hardening of the embedding mateπal generally occurs in the region of a few minutes If a reduction in the rate of hardening is desired, that can be achieved by means of lower temperatures Conversion can be implemented at ambient temperature, by increasing the temperature for example to 50°C solubility of the bιs-(4-amιno-2-halogeno-3.5-dιalkylphenyl )-methane for example in castor oil is increased so that a considerable reduction in the reaction time becomes a possibility The process according to the invention preferably uses bιs-(4-amιno-2- halogeno-3.5-dιalkylphenyl )-methane of the foregoing formula, in which Hal denotes chlorine Preferably in the bιs-(4-amιno-2-halogeno-3,5- dialylphenyl)-methane the substituents Rj to R 4 are all ethyl groups The process according to the invention can be used for any usual polyurethanes, in which respect hexamethylene dnsocyanate, diphenylmethane dnsocyanate, toluylene dnsocyanate. isophorone dnsocyanate. dicyclohexylmethane dnsocyanate or mixtures thereof are preferably used as component a) The hydrophobic polyhydπc alcohols which are usual for the medical sector such as polyester polyhydπc alcohols, polyether polyhydπc alcohols and castor oil or mixtures thereof can be used as the polyhydric alcohols Polyurethane resins which are known in the medical engineering sector as embedding materials, comprising hexamethylene dnsocyanate, pre- adducts and hydrophobic polyhydπc alcohols can be produced in accordance with the invention, with the advantages indicated Different metallo-orgamc compounds fall to be considered as the catalysts, in particular dioctyltm dilaurate. Example 1 A resin mixture is made up from the following components Bιs-(4-amιno-2-chloro-3.5-dιethylphenyl)-methane 5 % Castor oil 959553! Dioctyltm dilaurate 0.045 X An aliphatic isocyanate of the hexamethylene dnsocyanate type (Tolonate HDTLV from Rhone-Poulenc) was used as the hardener component That mixture was used to cast fibre bunches which had the following residual water contents a) 20 g of water per bunch = about 06 g of water per gram of bunch dry weight b) 40 g of water per bunch = about 1.25 g of water per gram of bunch dry weight c) 60 g of water per bunch = about 19 g of water per gram of bunch dry weight Result a) no bubble formation to be found b) no bubble formation to be found c) very slight bubble formation can be found Example 2 A resin mixture is made up from the following components: Bis-(4-amino-2-chloro-3,5-diethylphenyl)-methane 5 % Lupranol 3900 20 % (hydrophilic polyhydric alcohol ) Castor oil 74.962 % Dioctyltin dilaurate 0.038 % An aliphatic isocyanate of the HDI type (Tolonate HDTLV from Rhone- Poulenc) was used as the hardener component. That mixture was used to cast fibre bunches which had the following residual water contents: a) 20 g of water per bunch = about 0.6 g of water per gram of bunch dry weight b) 40 g of water per bunch = about 1.25 g of water per gram of bunch dry weight c) 60 g of water per bunch = about 1.9 g of water per gram of bunch dry weight Result: a) no bubble formation to be found b) very slight bubble formation to be found c) slight bubble formation can be found This Example shows that the tendency to a higher level of ' water sensitivity rises due to the use of hydrophilic resin components. In comparison with standard production in which a water content of about 0.03 to 0.04 g per gram of bunch dry weight can be tolerated, both Examples show that castings which are still acceptable can be produced with 15 to 40 times the amount of water on the bunch.

Claims: CLAIMS 1. A process for producing polyurethanes by reaction of a) di- and/or polyisocyanate. and b) di- and/or polyhydric alcohol in the presence of at least one metal compound as a catalyst characterised in that there is added to the reaction mixture at least one bis-(4-amino-2- halogeno-3,5-dialkylphenyl) -methane of the general formula: wherein Hal means CI or Br and R t to R„ are the same or different and each denote an alkyl group having 1 to 4 carbon atoms, and at least one metallo- organic compound is used as the catalyst. 2. A process according to claim 1 characterised in that a bis-(4-amiπo- 2-halogeno-3,5-d alkylphenyl)-methane is added, in which Hal means CI . 3. A process according to claim 1 or claim 2 characterised in that a bis-(4-amino-2-halogeno-3,5-dialkylphenyl)-methane is added, in which the substituents R x to R 4 denote ethyl . 4. A process according to one of claims 1 to 3 characterised in that from 3 to 20 % by weight, preferably from 5 to 10 % by weight of bis-(4-amino- 2-halogeno-3.5-dialkylphenyl)-methane, with respect to the total weight of a) + b). is added to the reaction mixture. 5. A process according to one of claims 1 to 4 characterised in that hexamethylene diisocyanate. diphenyl ethane diisocyanate. toluylene diisocyanate. isophorone diisocyanate, dicyclohexylmethane diisocyanate or mixtures thereof are used as component a). 6. A process according to one of claims 1 to 5 characterised in that castor oil, at least one polyester polyhydric alcohol, at least one polyether polyhydric alcohol or a mixture thereof is used as component b). 7. A process according to one of claims 1 to 6 characterised in that dioctyltin dilaurate is used as the catalyst. 8. A process according to one of claims 1 to 7 characterised in that the catalyst is added in such an amount that clouding of the reaction mixture just disappears. 9. A polyurethane article comprising a) di- and/or polyisocyanate residues, and b) di- and/or polyhydric alcohol residues and a content of at least one metal compound as a catalyst, characterised in that the polyurethane contains bound residues of bis-(4-amino-2-halogeno-3.5- dialkylphenyl) -methane of the general formula: wherein Hal means CI or Br and R λ to R 4 are the same or different and each denote an alkyl group having 1 to 4 carbon atoms, and the catalyst is a metallo-organic compound. 10. An article according to claim 9 characterised in that in the bis-(4- amino-2-halogeno-3,5-dialkylphenyl) -methane residues Hal denotes CI . 11. An article according to claim 9 or claim 10 characterised in that in the bis-(4-amino-2-halogeno-3,5-dialkylphenyl) -methane residues R l to R 4 are ethyl residues. 12. An article according to one of claims 9 to 11 characterised in that it contains about 3 to 20 % by weight, preferably 5 to 10 % by weight of bis- (4-amino-2-halogeno-3 ,5-dialkylphenyl ) -methane residues . 13. An article according to claims 9 to 12 characterised in that as polyisocyanate -residues it contains hexamethylene diisocyanate. diphenylmethane di isocyanate, to!uy1ene di isocyanate, isophorone di i socyanate. and/or dicyclohexylmethane diisocyanate residues. 14. An article according to one of claims 9 to 13 characterised in that it contains castor oil, polyester polyhydric alcohol and/or polyether polyhydric alcohol residues as the polyhydric alcohol residues. 15. An article according to one of claims 9 to 14 characterised in that t is an embedding of medical -engineering articles, in particular membranes

Inventors: BAUER ULRICH ROBERT, BAUER, ULRICH, ROBERT
Applicants: BAUER ULRICH ROBERT, GAMBRO DIALYSATOREN, BAUER, ULRICH, ROBERT, GAMBRO DIALYSATOREN GMBH & CO. KG
Application year: 1999
Main classification: C08G18
IPC codes: B01D63, B01D65, C08G18