Abstract:
The present invention relates to high-quality polyurethane and polyurethane urea elastomers which exhibit unique combinations of processing characteristics, oxidation resistance, mechanical and mechanical/dynamic properties in particularly demanding applications. These polyurethane elastomers and polyurethane urea elastomers are based on novel polycarbonate polyols.

Description:
CROSS REFERENCE TO RELATED PATENT APPLICATION 
     The present patent application claims the right of priority under 35 U.S.C. §119 (a)-(d) of German Patent Application No. 10 2007 032 343.5, filed Jul. 11, 2007. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to high-quality polyurethane (PU) elastomers and polyurethane urea elastomers which exhibit unique combinations of processing characteristics, oxidation resistance, mechanical and mechanical/dynamic properties in particularly demanding applications. These polyurethane elastomers and polyurethane urea elastomers are based on novel polycarbonate polyols. 
     Polyurethane elastomers were first sold commercially over 60 years ago by Bayer MaterialScience AG under the trade name Vulkollan®, based on 1,5-naphthalene diisocyanate (NDI, which is commercially available from Bayer MaterialScience AG), a long-chain polyester polyol and a short-chain alkanediol. 
     In addition to polyester polyols, polyether polyols, polycarbonate polyols and polyether ester polyols are also used as long-chain polyols. The choice of long-chain polyol is determined primarily by the requirements of the individual application. The concept of “customised properties” is also used in this connection. For example, polyether polyols are used if hydrolysis resistance and low-temperature properties are a priority. Polyester polyols have advantages over polyether polyols in terms of mechanical properties and UV stability. However, their low microbe resistance is a disadvantage. Polycarbonate polyols combine to some extent the advantages of polyether polyols and polyester polyols, but they are relatively expensive in comparison. 
     The advantages of polycarbonate polyols lie in particular in their UV stability, hydrolysis resistance and their mechanical properties. 
     The disadvantage of polyester polyols and polycarbonate polyols and their mixed types, polyester carbonate polyols, as compared with polyether polyols lies in their generally less advantageous low-temperature characteristics. This is due to structural factors and is based on the elevated polarity of carbonyl groups, which normally means that polyester polyols and polycarbonate polyols are partially crystalline, whereas polyether polyols, especially the propylene oxide-based types as the commercially largest group, are amorphous. For partially crystalline systems the relation between glass transition temperature (T g ) and melt temperature (T m ) is described by the known empirical rule established by Beaman and Bayer (M. D. Lechner, K. Gehrke and E. H. Nordmeier, Makromolekulare Chemie, Birkhäuser Verlag 1993, page 327)
 
 T   g =2/3 T   m   (I)
 
     For example, if polycarbonate polyols have melt temperatures for the partially crystalline components of around 70° C. (343° K), the glass transition temperatures of the amorphous regions are in the order of magnitude of −43° C. (230° K). These values largely also apply if the polycarbonate polyols are present as soft segment polyols in segmented multi-block copolyurethanes, e.g. in the form of thermoplastic polyurethane elastomers (TPU) or polyurethane cast elastomers in integrated form. It is clear from this that it is desirable to have polycarbonate polyols which have a melting range as low as possible. On the one hand, this simplifies processing, and on the other, the working temperature range is extended down to lower temperatures as a consequence of the glass transition temperature, which is likewise reduced. 
     The upper limit of the working temperature range is determined by the thermal properties of the rigid segments (e.g. urethane, urea, isocyanurate groups, etc.), i.e. the structural elements present in the polyisocyanate building blocks. 
     The disadvantage of using 1,6-hexanediol as the diol component for polycarbonate polyols or polyadipate polyols, for example, as used in polyurethane chemistry, is the elevated viscosity with otherwise identical characteristic values (molecular weight and functionality). 
     There have been a number of attempts to modify the melting range of hexanediol polycarbonate polyol, which in industry is the most important polycarbonate polyol for polyurethane elastomers, in such a way as to cover the specific requirements of as many applications as possible. For example, in DE-A 3717060 part of the hexanediol is replaced by hexanediol ether units, for example, leading to a reduced crystalline proportion as compared with pure hexanediol polycarbonate polyol and a melting range shifted to lower temperatures. The disadvantage of this process, however, is that the incorporation of ether groupings has a negative influence on the oxidation and heat ageing resistance, as a result of which some important applications are not viable. 
     H. Tanaka and M. Kunimura (Polymer Engineering and Science, vol. 42, no. 6, page 1333 (2002)) indicate a way of eliminating at least the aforementioned disadvantage by using 1,6-hexanediol and 1,12-dodecanediol to produce copolycarbonate polyols which have markedly lower melt temperatures than their homopolycarbonate polyols. With the aid of the measurement technique they were using, they measured the melting point of hexanediol polycarbonate polyol at 47.4° C. and that of 1,12-dodecane polycarbonate polyol at 65.5° C., whereas a copolycarbonate polyol with a composition of 70 parts by weight of hexanediol to 30 parts by weight of 1,12-dodecanediol melts at 29.1° C.; this represents a lowering of the melting range by 18.3° C. and 36.3° C., respectively, as compared with the homopolymers. The values for the heat of fusion [J/g] behave in a similar manner, displaying a minimum when the polycarbonate polyol consists of 70 parts of hexanediol and 30 parts of 1,12-dodecanediol. 
     In spite of these in principle promising approaches, which incidentally were also used on thermoplastic polyurethane elastomers synthesised therefrom, it has so far not been possible to implement this method on an industrial scale, or at least not to any significant extent. 
     A substantial reason for this is that 1,12-dodecanediol in particular is so expensive that the resulting price of the polycarbonate polyol or copolycarbonate polyol and hence ultimately of the polyurethane elastomer is so high that the advantages that might arise from using 1,12-dodecanediol in whole or in part are outweighed. 
     This means that any technical advantages would be achieved at too high a cost. 
     Therefore, an object of the present application was to provide polyurethanes which do not have the aforementioned disadvantages. 
     SUMMARY OF THE INVENTION 
     The invention relates to polycarbonate polyols having an OH value of 50 to 80 mg KOH/g and an average functionality of 1.9 to 2.2. These polycarbonate polyols are the reaction product of
     (1) a mixture comprising
       A) one or more α,ω-alkanediols having 4 to 8 carbon atoms,   B) technical dodecanediol which comprises (1) 30 to 50 wt. % of 1,12-dodecanediol, (2) 5 to 20 wt. % of diols having fewer than 10 carbon atoms and (3) no diols having more than 12 carbon atoms, and wherein the technical dodecanediol is present in an amount of from 15 wt. % to 85 wt. %, based on the total weight of the mixture of A) and B),   and   C) 0 to 10 wt. %, based on the total weight of the mixture of A), B) and C), of one or more alkanols having 4 to 10 carbon atoms and a hydroxyl functionalities of 1 to 3;   
       with   (2) a carbonyl component from the group consisting of diaryl carbonates, dialkyl carbonates and carbonyl chloride.   

     A process for the preparation of these novel polycarbonate polyols is also provided. 
     The present invention also relates to NCO prepolymers prepared from these novel polycarbonate polyols with a polyisocyanate component, and to a process for the preparation of these NCO prepolymers. 
     In addition, this invention relates to polyurethane elastomers and/or polyurethane urea elastomers comprising the reaction product of the NCO prepolymers prepared from the polycarbonate polyols and one or more chain extenders. A process for the preparation of these elastomers is also provided herein. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The molecular weight of the polycarbonate polyols of the present invention is in the range of from about 1200 to about 2500 Da. The viscosity of these polycarbonate polyols, measured at 75° C., is between about 900 and about 2600 mPas, and these have an average functionality in the range of from about 1.9 to about 2.2. This is achieved by optionally adding monools or polyols to the mixture used to prepare the polycarbonate polyols. Examples of suitable polyols and monools in this connection include but are not limited to 1,1,1-trimethylol propane and 1-octanol, respectively. Functionalities below 2 can also be achieved by not completely reacting the dialkyl carbonates and/or diaryl carbonates used so that alkyl carbonate and/or aryl carbonate end groups are formed. 
     The reaction of (1) the mixture of components A), B) and optionally C), with (2) the carbonyl component takes place by methods known to the person skilled in the art. Carbonyl chloride (i.e. phosgene), dialkyl carbonates and/or diaryl carbonates can be used as (2) the carbonyl component. Dimethyl carbonate and/or diphenyl carbonate are preferred carbonyl components. 
     In accordance with the present invention, the polycarbonate polyols can then be processed further, preferably via a prepolymer stage, to form polyurethane (PU) materials. These polyurethane materials can be prepared by reacting the polycarbonate polyols of the invention, optionally with the added use of short-chain organic compounds having hydroxyl end groups and/or amino end groups and/or water, with polyisocyanates, preferably diisocyanates. 
     The invention also provides NCO prepolymers having an NCO group content of 3 to 15 wt. %. These NCO prepolymers are obtained by reacting polycarbonate polyols of the invention, and a polyisocyanate selected from the group consisting of 1,5-naphthalene diisocyanate, 2,4′-diphenylmethane diisocyanate (2,4′-MDI), 4,4′-diphenylmethane diisocyanate (4,4′-MDI), mixtures of 2,4′-diphenylmethane diisocyanate and 4,4′-diphenylmethane diisocyanate, carbodiimide-/uretonimine-modified diphenylmethane diisocyanate derivatives, polynuclear homologues of the diphenylmethane series, diisocyanatotoluenes, hexamethylene diisocyanate, isophorone diisocyanate, with the isocyanate component being present in a molar excess. More specifically, it is preferred that the polyisocyanate and the polycarbonate polyols are present in amounts such that the molar ratio of NCO to OH groups is from 2:1 to 10:1. 
     The present invention also provides polyurethane elastomers and/or polyurethane urea elastomers which are obtained by reacting NCO prepolymers as described herein, with an isocyanate-reactive blend of (i) one or more aliphatic diols having primary hydroxyl groups and number-average molecular weights of 62 to 202, optionally, in amounts of 0-10 wt. %, based on the weight of the aliphatic diols, of compounds selected from the group consisting of short-chain polyols with functionalities &gt;2 to 4, higher-molecular-weight polyols with a functionality of 2 and polycarbonate polyols according to the invention, or (ii) one or more aromatic diamine-type chain extenders selected from the group consisting of 4,4′-methylene-bis-(2-chloroaniline) (MBOCA), 3,3′,5,5′-tetraisopropyl-4,4′-diamino-diphenylmethane, 3,5-dimethyl-3′,5′-diisopropyl-4,4′-diaminophenylmethane, 3,5-diethyl-2,4-toluene diamine, 3,5-diethyl-2,6-toluene diamine (DETDA), 4,4′-methylene-bis-(3-chloro-2,6-diethylaniline), 3,5-dimethylthio-2,4-toluene diamine, 3,5-dimethylthio-2,6-toluene diamine and 3,5-diamino-4-chlorobenzoic acid isobutyl ester, optionally, in the presence of water, and/or further auxiliary substances and additives. 
     Suitable aliphatic diols to be used herein include butanediol, hexanediol, cyclohexanediol, 2,2′-thiodiethanol or mixtures thereof. These diols are preferred. 
     If water is used as a chain extender and/or as a blowing agent, the polyurethane elastomers preferably have densities of 0.3 to 0.9 g/cm 3 . 
     The polyurethane and polyurethane urea elastomers are preferably produced by the casting method, wherein there are substantially two different processes. The first is the NCO prepolymer method, in which long-chain polyol (i.e. the polycarbonate polyol) and polyisocyanate in stoichiometric excess are reacted to form a prepolymer having NCO groups, and then subjecting this prepolymer to chain extension with a short-chain organic compound having hydroxyl end groups or amino end groups, and/or water. Secondly, PU cast elastomers can also be produced by the one-shot method, in which long-chain polyol and short-chain organic compounds are mixed with hydroxyl end groups or amino end groups, and/or water, and then reacted with a polyisocyanate. 
     In addition to polyurethane cast elastomers, polyurethane elastomers suitable for thermoplastic processing can also be produced from the polycarbonate polyols of the invention by methods known to the person skilled in the art. 
     In addition to the components described above as suitable for the present invention, the conventional catalysts and auxiliary agents can also be used in the production of the polyurethane or polyurethane urea elastomers. 
     Examples of suitable catalysts are trialkylamines, diazabicyclooctane, tin dioctoate, dibutyl tin dilaurate, N-alkyl morpholine, lead octoate, zinc octoate, calcium octoate, magnesium octoate, the corresponding naphthenates, p-nitrophenolate, etc. 
     Examples of suitable stabilizers are Brønsted acids and Lewis acids including, for example, hydrochloric acid, benzoyl chloride, organomineral acids, for example, dibutyl phosphate, also adipic acid, malic acid, succinic acid, racemic acid or citric acid. 
     Examples of UV stabilizers and hydrolysis stabilizers are, for example, 2,6-dibutyl-4-methylphenol and carbodiimides. 
     Incorporable dyes which can likewise be used are those which have Zerewitinoff-active hydrogen atoms that can react with NCO groups. 
     Other auxiliary substances and additives include emulsifiers, foam stabilizers, cell regulators and fillers. An overview can be found in G. Oertel, Polyurethane Handbook, 2 nd  edition, Carl Hanser Verlag, Munich, 1994, chapter 3.4. 
     The use of the polyurethane elastomers according to the invention lies in the area of technical components, and is thus, extremely wide-ranging. It includes, for example, roller coatings, electrical encapsulation, pipeline pigs, knives, wheels, rollers, screens, etc. 
     The following examples further illustrate details for the process of this invention. The invention, which is set forth in the foregoing disclosure, is not to be limited either in spirit or scope by these examples. Those skilled in the art will readily understand that known variations of the conditions of the following procedures can be used. Unless otherwise noted, all temperatures are degrees Celsius and all percentages are percentages by weight. 
     EXAMPLES 
     Composition of the Raw Materials Used in the Examples 
     
         
         T12DD: Technical dodecanediol commercially available from Invista which comprised a mixture of (1) 30 to 50 wt. % of 1,12-dodecanediol, (2) 5 to 20 wt. % of one or more diols having few than 10 carbon atoms and (3) no diols having more than 12 carbon atoms 
         DPC: diphenyl carbonate 
         Hexanediol: 1,6-Hexanediol commercially available from Aldrich 
         4,4′-MDI: 4,4′-diphenylmethane diisocyanate 
         1,5-NDI: 1,5-naphthalene diisocyanate 
         Magnesium hydroxide carbonate: as pentahydrate commercially available from Aldrich 
         Dibutyl phosphate: dibutyl phosphate commercially available from Aldrich 
         Crosslinker RC 1604: a crosslinker commercially available from Rheinchemie 
         Butanediol: 1,4-Butanediol from Aldrich 
         Baytec® VPPU 0385: Ether group-containing polycarbonate polyol from Bayer MaterialScience AG with a hydroxyl value of 56 mg KOH/g and a functionality of 2 
         TMP: 1,1,1-Trimethylolpropane from Aldrich 
         Crosslinker 10GE32: Crosslinker from Bayer MaterialScience AG 
       
    
     The viscometer used to determine the viscosity of materials in the examples was a MCR 51 from Anton Paar. 
     A Lambda 25 UV/Vis spectrometer from Perkin Elmer was used for the photometric determination of aromatic end groups (e.g. phenoxy and phenyl carbonate) and of free phenol in polycarbonate polyols. 
     A) Production of Polycarbonate Polyols 
     Example A3 
     According to the Invention 
     2946 g (15.34 mol) of T12DD, 1264 g (10.71 mol) of hexanediol (i.e. 70 wt. % of T12DD based on the combined weight of T12DD and hexanediol) and 4952 g (23.14 mol) of DPC and 160 mg of magnesium hydroxide carbonate were heated to 180° C. for 90 minutes in a distillation apparatus under nitrogen whilst stirring. The mixture was then cooled to 110° C., a vacuum (15 mbar) was applied and phenol was removed by distillation. When phenol distillation slowed down, the bottom temperature was increased in small increments over 10 hours to reach 200° C., the overhead temperature not being permitted to rise above 80° C. Distillation was carried out for approx. 1 hour at 200° C. and 15 mbar, and then for about an additional 1 hour at 200° C. and under a pressure of below 1 mbar. In this phase, phenol residues were driven out of the column with a hot air blower. After cooling to around 80° C., a sample was taken. The OH value, the end groups (by photometry) and the viscosity were determined. The mixture was then neutralised at 80° C. by stirring in 960 mg of dibutyl phosphate. 
     OH value: 60 mg KOH/g 
     Viscosity: 1180 mPas (75° C.) 
     End groups: Phenol: 0.02 wt. %, phenoxy and phenyl carbonate: not detectable 
     Examples A1, A2 and A4 were carried out in the same way as Example A3. The relevant data for each Example can be found in Table 1. 
                                                                               TABLE 1                   Polycarbonate polyols                Example                A.1. (C)   A.2.   A.3.   A.4. (C)                        T12DD content   [wt. %]   0   30   70   10       OH value   [mg KOH/g]   56.4   54.9   60.0   58.9       Viscosity [75° C.]   [mPas]   2850   2180   1180   790               (C) = Comparison            
B) Production of MDI prepolymers:
 
     Example B3 
     According to the Invention 
     1850 g (7.4 mol) of 4,4′-MDI were introduced into a 6 liter three-necked flask with heating mantle, stirrer and internal thermometer under a nitrogen blanket at 50° C. whilst stirring. Then, 3001 g of a polycarbonate polyol from Example A3 which was preheated to 80° C. were added over approx. 10 minutes whilst stirring. Stirring was then continued under nitrogen at 80° C. The reaction was completed after 2 hours. The NCO group content was 10.0 wt. % and the viscosity was 2050 mPas (at 70° C.). 
     The NCO prepolymer was stored in a glass flask at room temperature and remained liquid and resistant to sedimentation for a period of over 3 months. 
     Examples B1, B2 and B4 were performed in the same way as Example B3, except that instead of polycarbonatediol A3, polycarbonate diols A1, A2 and A4 were used in these Examples, respectively. The relevant data can be found in Table 2. 
     
       
         
               
             
               
               
             
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 NCO prepolymers based on polycarbonate polyols A1 to A4 with 
               
               
                 NCO contents of 10 wt. % 
               
             
          
           
               
                   
                 Example 
               
             
          
           
               
                   
                 B1 (C) 
                 B2 
                 B3 
                 B4 (C) 
               
               
                   
                   
               
             
          
           
               
                 Polycarbonatediol 
                   
                 A1 (C) 
                 A2 
                 A3 
                 A4 (C) 
               
               
                 Viscosity (at 70° C.) 
                 [mPas] 
                 4220 
                 3180 
                 2050 
                 1447 
               
               
                 Resistant to crystallisation (at 
                   
                 No 
                 Yes 
                 Yes 
                 No 
               
               
                 room temperature) 
               
               
                 Resistant to sedimentation 
                   
                 No*) 
                 No 
                 Yes 
                 No*) 
               
               
                 (after 3 months and at room 
               
               
                 temperature) 
               
               
                   
               
               
                 *)These samples solidify completely when left to stand at room temperature 
               
               
                 (C) = Comparison 
               
             
          
         
       
     
     Table 2 shows that prepolymer B3 which was produced from polycarbonate polyol A3 in accordance with the present invention, has particularly favorable properties. In particular, Example B3 has a viscosity below 2500 mPas (70° C.) and exhibits good resistance to crystallisation and sedimentation at room temperature. The prepolymer B2 is still perfectly useable but has a higher viscosity than prepolymer B3. In the case of prepolymer B1 (comparison) and prepolymer B4 (comparison) produced from polycarbonate polyol A1 (comparison) and polycarbonate polyol A4 (comparison), a sediment quickly forms at room temperature, and both NCO prepolymers solidify completely when stored at room temperature. 
     C) Production of Cast Elastomers: 
     1) Chain Extension with 1,4-butanediol: 
     100 parts of a prepolymer (from Example B) preheated to 70° C. and degassed were stirred for 30 seconds with 10.15 parts of 1,4-butanediol. The reacting melt was poured into metal molds heated to 115° C. and annealed at 110° C. for 24 hours. After storing at room temperature for 21 days the mechanical data was determined (see Table 3). In the formulations in Table 3, all of the amounts shown are parts by weight. 
     2) Chain Extension with Crosslinker RC 1604: 
     100 parts of a prepolymer (from Example B) preheated to 70° C. and degassed were stirred for 30 seconds with 26.5 parts of crosslinker RC 1604 (crosslinker temperature: 105° C.). The reacting melt was poured into metal molds heated to 115° C. and annealed at 110° C. for 24 hours. After storing at room temperature for 21 days the mechanical data was determined (see Table 3). In the formulations in Table 3, all of the amounts shown are parts by weight. 
                                                                                                                                 TABLE 3                   Production and properties of polyurethane and polyurethane urea elastomers by reacting the MDI prepolymers with       butanediol or crosslinker 1604                Example                        C1-1 (C)   C2-1 (C)   C1-2   C2-2   C1-3   C2-3   C1-4 (C)   C2-4 (C)               Formulation:   Prepolymer       B1 (C)   B1 (C)   B2   B2   B3   B3   B4 (C)   B4 (C)           MDI prepolymer   [parts]   100   100   100   100   100   100   100   100           NCO content of prepolymer   [%]   10.01   10.01   10   10   10.0   10   10.02   10.02           Prepolymer viscosity (70° C.)   [mPas]   4220   4220   3180   3180   2050   2050   1447   1447           Crosslinker 1604   [parts]   —   26.5   —   26.5   —   26.5   —   26.5           1,4-Butanediol   [parts]   10.15   —   10.15   —   10.15   —   10.15   —       Processing:   Prepolymer temperature   [° C.]   70   70   70   70   70   70   70   70           Crosslinker temperature   [° C.]   23   105   23   105   23   105   23   105           Casting time   [s]   125   28   130   48   120   40   135   43           Retraction time   [min]   7   3   6   3   5   3   7   3           Table temperature   [° C.]   116   116   116   116   116   116   116   116           Mold temperature   [° C.]   110   110   110   110   110   110   110   110           Release time   [min]   24   24   24   24   24   24   24   24            Mechanical properties:            DIN 53505   Shore A       97   100   97   100   97   100   98   100       DIN 53505   Shore D       49   71   49   71   48   69   50   70       DIN 53504   Tensile modulus 100%   [MPa]   15.56   31.31   15.51   29.87   12.52   26.72   12.23   24.74       DIN 53504   Tensile modulus 300%   [MPa]   35.15   —   26.97   —   —   —   —   —       DIN 53504   Yield stress   [MPa]   37.91   40.67   27.63   37.58   14.76   32.89   12.86   29.56       DIN 53504   Ultimate elongation   [%]   364   186   351   171   205   205   201   212       DIN 53515   Graves   [kN/m]   123   170   97   159   77   156   65   141           Impact resilience   [%]   43   56   48   57   51   57   49   57       DIN 53516   Abrasion (DIN)   [mm 3 ]   23   44   23   52   —   —   —   —       DIN 53420   Density   [g/mm 3 ]   1.200   1.210   1.177   1.185   —   —   —   —       DIN 53517   Compression set 22° C.   [%]   18.3   59.6   18.3   58.9   21.9   65.1   29.2   63.4       DIN 53517   Compression set 70° C.   [%]   33.0   82.9   38.9   86.0   43.3   84.5   47.8   85.4                    
D) Production of Cast Elastomers Based on 1,5-Naphthalene Diisocyanate:
 
     93.3 parts of a polycarbonate polyol (from Example A3) preheated to 125° C. were stirred with differing amounts of 1,5-naphthalene diisocyanate (1,5-NDI), a vacuum of approx. 15 mbar was applied until constancy of temperature was reached. Differing amounts of chain extenders were then stirred in for 30 seconds. The reacting melt was poured into metal molds heated to 115° C. and annealed at 110° C. for 24 hours. After storing at room temperature for 21 days the mechanical data was determined (see Table 4B). In the formulations in Table 4A, all of the amounts shown are parts by weight. 
     E) Production of Cast Elastomers (not According to the Invention) 
     Baytec® VPPU 0385 is a commercial product based on 1,6-hexanediol and diphenyl carbonate. 
     The polycarbonate Baytec® VPPU 0385 was reacted with 1,5-NDI to form an NCO prepolymer. This prepolymer was then chain extended to obtain the NDI cast elastomer, in which the chain extension was performed with 1,4-butanediol. Preparation of the cast elastomer was as described in Example D). 100 parts by weight of polycarbonate polyol, 18 parts by weight of 1,5-NDI and 2 parts by weight of 1,4-butanediol were used. 
     
       
         
               
             
               
               
             
               
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 4A 
               
             
             
               
                   
               
               
                 Production and properties of cast elastomers based on polyol A3 and NDI 
               
             
          
           
               
                   
                 Formulation: 
               
             
          
           
               
                   
                 D1 
                 D2 
                 D3 
                 D4 
                 D5 
                 D6 
                 D7 
                 D8 
                 D9 
                 D10 
               
               
                   
                   
               
             
          
           
               
                   
                 Polyol A3 
                 [parts] 
                 93.3 
                 93.3 
                 93.3 
                 93.3 
                 93.3 
                 93.3 
                 93.3 
                 93.3 
                 93.3 
                 93.3 
               
               
                   
                 1,5-NDI 
                 [parts] 
                 18 
                 25 
                 21 
                 27 
                 30 
                 18 
                 18 
                 18 
                 18 
                 18 
               
               
                   
                 1,4-Butanediol 
                 [parts] 
                 2 
                 5 
                 3.4 
                 5.8 
                 — 
                 2 
                 2.3 
                 2 
                 2.3 
                 2.3 
               
               
                   
                 TMP 
                 [%] 
                 — 
                 — 
                 — 
                 — 
                 — 
                 10 
                 20 
                 30 
                 40 
                 60 
               
               
                   
                 Crosslinker 10GE32 
                 [parts] 
                 — 
                 — 
                 — 
                 — 
                 9.5 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                 Processing: 
                 Polyol temperature 
                 [° C.] 
                 122 
                 125 
                 126 
                 130 
                 133 
                 122 
                 122 
                 122 
                 122 
                 122 
               
               
                   
                 Reaction time 
                 [min] 
                 10 
                 9 
                 7 
                 8 
                 7 
                 10 
                 10 
                 9 
                 11 
                 10 
               
               
                   
                 Temperature 
                 [° C.] 
                 132.8 
                 128.5 
                 126.5 
                 127.9 
                 127.1 
                 129.4 
                 129.1 
                 129.4 
                 130 
                 128.7 
               
               
                   
                 maximum 
               
               
                   
                 Casting time 
                 [s] 
                 105 
                 35 
                 60 
                 25 
                 165 
                 105 
                 105 
                 110 
                 180 
                 190 
               
               
                   
                 Setting time 
                 [min] 
                 16 
                 7 
                 7 
                 5 
                 9 
                 17 
                 19 
                 23 
                 25 
                 60 
               
               
                   
                 Table temperature 
                 [° C.] 
                 116 
                 116 
                 116 
                 116 
                 116 
                 116 
                 116 
                 116 
                 116 
                 116 
               
               
                   
                 Mold temperature 
                 [° C.] 
                 110 
                 110 
                 110 
                 110 
                 110 
                 110 
                 110 
                 110 
                 110 
                 110 
               
               
                   
                 Release time 
                 [min] 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                   
                 Post-cure temperature 
                 [° C.] 
                 110 
                 110 
                 110 
                 110 
                 110 
                 110 
                 110 
                 110 
                 110 
                 110 
               
               
                   
                 Post-cure time 
                 [h] 
                 24 
                 24 
                 24 
                 24 
                 24 
                 24 
                 24 
                 24 
                 24 
                 24 
               
               
                   
                 Prep viscosity (120° C.) 
                 [mPas] 
                 4865 
                 1625 
                 2615 
                 1310 
                 1040 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                   
               
             
          
         
       
     
                                                                                                                                         TABLE 4B                   Production and properties of cast elastomers based on polyol A3 and NDI                Formulation:                D1   D2   D3   D4   D5   D6   D7   D8   D9   D10                        Mechanical properties:            DIN 53505   Shore A       94   97   96   97   98   93   92   92   91   85       DIN 53505   Shore D       38   44   41   47   49   36   35   35   33   28       DIN 53504   Tensile modulus   [MPa]   8.70   13.62   10.85   13.97   14.68   8.13   7.82   7.56   7.06   5.52           100%       DIN 53504   Tensile modulus   [MPa]   16.09   19.03   15.84   19.09   19.38   15.27   15.20   15.58   16.70   16.63           300%       DIN 53504   Yield stress   [MPa]   26.99   23.58   23.92   21.38   23.03   26.83   26.02   27.37   26.66   23.86       DIN 53504   Ultimate   [%]   459   468   509   388   422   451   417   414   376   336           elongation       DIN 53515   Graves   [kN/m]   62   80   21   86   106   53   47   41   31   75           Impact resilience   [%]   62   62   62   62   57   60   59   58   56   50       DIN 53516   Abrasion (DIN)   [mm 3 ]   27   30   29   37   30   27   29   29   35   34       DIN 53517   Compression set   [%]   18.3   18.4   19.7   22.3   20.8   18.9   18.1   18.0   16.5   15.2           22° C.       DIN 53517   Compression set   [%]   33.6   33.5   34.3   36.8   35.8   35.2   34.0   34.6   33.0   30.0           70° C.       DIN 53517   Compression set   [%]   51.2   48.3   46.8   50.4   48.5   50.9   48.4   48.7   48.8   40.6           100° C.       DIN 53517   Compression set   [%]   83.7   77.6   72.5   76.2   73.6   93.7   91.8   83.9   84.9   82.0           120° C.                    
F) Hydrolysis and Hot-Air Ageing of NDI Cast Systems
 
     It was able to be shown that the systems according to the invention have excellent properties in terms of their behavior with regard to hydrolysis and hot-air ageing, and are superior to conventional systems. 
     
       
         
               
             
               
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 5 
               
             
             
               
                   
               
               
                 Hydrolysis characteristics and hot-air ageing (as determined by 
               
               
                 DIN 53508) of the NDI cast elastomer according to the invention of 
               
               
                 Example D1) 
               
             
          
           
               
                   
                 [days] 
               
             
          
           
               
                   
                 0 
                 7 
                 14 
                 21 
                 42 
                 56 
                 63 
               
               
                   
                   
               
             
          
           
               
                 Storage in water at 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 100° C. 
               
               
                 Shore A 
                   
                 94 
                 91 
                 90 
                 90 
                 91 
                 92 
                 92 
               
               
                 Tensile modulus 
                 [MPa] 
                 8.70 
                 6.10 
                 6.03 
                 5.26 
                 6.22 
                 6.17 
                 6.29 
               
               
                 100% 
               
               
                 Tensile modulus 
                 [MPa] 
                 11.71 
                 8.19 
                 7.72 
                 7.15 
                 7.27 
                 7.45 
                 7.22 
               
               
                 200% 
               
               
                 Tensile modulus 
                 [MPa] 
                 16.09 
                 10.10 
                 9.13 
                 8.72 
                 7.60 
                 8.07 
                 7.61 
               
               
                 300% 
               
               
                 Yield stress 
                 [MPa] 
                 26.99 
                 16.83 
                 12.53 
                 11.06 
                 7.51 
                 8.17 
                 7.54 
               
               
                 Ultimate elongation 
                 [%] 
                 459 
                 653 
                 615 
                 515 
                 330 
                 350 
                 317 
               
               
                 Storage in air at 
               
               
                 150° C. 
               
               
                 Shore A 
                   
                 94 
                 96 
                 91 
                 89 
                 89 
                 90 
                 87 
               
               
                 Tensile modulus 
                 [MPa] 
                 8.70 
                 6.63 
                 6.08 
                 5.69 
                 5.57 
                 5.75 
                 5.69 
               
               
                 100% 
               
               
                 Tensile modulus 
                 [MPa] 
                 11.71 
                 8.30 
                 7.75 
                 7.56 
                 7.39 
                 7.43 
                 7.45 
               
               
                 200% 
               
               
                 Tensile modulus 
                 [MPa] 
                 16.09 
                 9.74 
                 9.33 
                 9.33 
                 9.17 
                 8.97 
                 8.85 
               
               
                 300% 
               
               
                 Yield stress 
                 [MPa] 
                 26.99 
                 17.50 
                 16.90 
                 15.99 
                 14.77 
                 13.29 
                 13.42 
               
               
                 Ultimate elongation 
                 [%] 
                 459 
                 684 
                 709 
                 622 
                 567 
                 566 
                 599 
               
               
                   
               
             
          
         
       
     
     Table 5 shows that the NDI cast elastomer DI also withstands extreme loads. The sharpest drop in mechanical data occurs right at the start of loading, in other words between 0 and 7 days. This behavior is typical of such tests, however. From this point onwards, the system according to the invention changes only marginally and displays virtually constant values even in a hot-air ageing test at 150° C. over 9 weeks at tensile modulus values of 100%, 200% and 300%. By contrast, a comparable, conventional system exhibits a greater drop in mechanical data after just 14 days at only 130° C. (see Table 6). The same applies with regard to storage in water. 
     
       
         
               
             
               
               
             
               
               
               
               
               
               
             
               
               
             
               
               
               
               
               
               
             
           
               
                 TABLE 6 
               
               
                   
               
               
                 Hydrolysis characteristics and hot-air ageing (as determined by 
               
               
                 DIN 53508) of an NDI cast elastomer not according to the invention - 
               
               
                 Example E) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 [days] 
               
             
          
           
               
                 Storage in water at 80° C. 
                   
                 0 
                 3 
                 14 
                 28 
               
               
                   
               
               
                 Shore A 
                   
                 89 
                 88 
                 87 
                 87 
               
               
                 Tensile modulus 100% 
                 [MPa] 
                 5.4 
                 5.8 
                 4.9 
                 4.9 
               
               
                 Tensile modulus 300% 
                 [MPa] 
                 9.5 
                 10.2 
                 8.4 
                 8.1 
               
               
                 Yield stress 
                 [MPa] 
                 42.4 
                 35.6 
                 30.3 
                 26.0 
               
               
                 Ultimate elongation 
                 [%] 
                 638 
                 603 
                 679 
                 740 
               
               
                   
               
             
          
           
               
                   
                 [days] 
               
             
          
           
               
                   
                 Storage in air at 130° C. 
                   
                 0 
                 3 
                 14 
               
               
                   
                   
               
               
                   
                 Shore A 
                   
                 89 
                 87 
                 85 
               
               
                   
                 Tensile modulus 100% 
                 [MPa] 
                 5.4 
                 5.5 
                 5.2 
               
               
                   
                 Tensile modulus 300% 
                 [MPa] 
                 9.5 
                 8.6 
                 8.0 
               
               
                   
                 Yield stress 
                 [MPa] 
                 42.4 
                 29.2 
                 22.7 
               
               
                   
                 Ultimate elongation 
                 [%] 
                 638 
                 748 
                 723 
               
               
                   
                   
               
             
          
         
       
     
     Although the invention has been described in detail in the foregoing for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims.