CA2640685A1 - Polyurethane cast elastomers formed from nco prepolymers based on 2,4'-mdi, a process for their preparation and their use - Google Patents
Polyurethane cast elastomers formed from nco prepolymers based on 2,4'-mdi, a process for their preparation and their use Download PDFInfo
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- CA2640685A1 CA2640685A1 CA002640685A CA2640685A CA2640685A1 CA 2640685 A1 CA2640685 A1 CA 2640685A1 CA 002640685 A CA002640685 A CA 002640685A CA 2640685 A CA2640685 A CA 2640685A CA 2640685 A1 CA2640685 A1 CA 2640685A1
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/08—Processes
- C08G18/10—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/40—High-molecular-weight compounds
- C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/40—High-molecular-weight compounds
- C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
- C08G18/4236—Polycondensates having carboxylic or carbonic ester groups in the main chain containing only aliphatic groups
- C08G18/4238—Polycondensates having carboxylic or carbonic ester groups in the main chain containing only aliphatic groups derived from dicarboxylic acids and dialcohols
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
- C08G18/72—Polyisocyanates or polyisothiocyanates
- C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
- C08G18/76—Polyisocyanates or polyisothiocyanates cyclic aromatic
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
- C08G18/72—Polyisocyanates or polyisothiocyanates
- C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
- C08G18/76—Polyisocyanates or polyisothiocyanates cyclic aromatic
- C08G18/7657—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings
- C08G18/7664—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings containing alkylene polyphenyl groups
- C08G18/7671—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings containing alkylene polyphenyl groups containing only one alkylene bisphenyl group
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- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Polyurethanes Or Polyureas (AREA)
Abstract
The present invention relates to novel polyurethane (PUR) cast elastomers formed from NCO-functional prepolymers based on 2,4'-MDI and aminic chain extenders and/or crosslinkers, to a process for their preparation and to their use.
Description
BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 Polyurethane casting elastomers made of NCO prepolymers based on 2,4'-MDI, a process for their preparation and their use The present invention relates to novel polyurethane (PUR) casting elastomers made of NCO-functional prepolymers based on 2,4'-MDI and amine-based chain extenders and/or crosslinking agents, to a process for their preparation and to their use.
MDI (diphenylmethane diisocyanate) is a technically important group of poly-isocyanates; it has a very heterogeneous composition in terms of its structure and comprises monomer grades characterized in that they have two aromatic structural elements bonded via a single methylene bridge, and higher oligomers having more than two aromatic structural elements and possessing more than one methylene bridge, which are referred to as polymeric MDI.
Monomeric MDI contains predominantly the 4,4' and 2,4' isomers as a consequence of its synthesis. The 2,2' isomer also occurs to a lesser extent, but is largely of no technical value.
The ratio of monomeric MDI to polymeric MDI, and the proportions of the 2,4' and 4,4' isomers in monomeric MDI, can be varied within wide limits by varying the conditions of synthesis of the precursor.
The crude MDI obtained in the MDI synthesis is separated substantially by distillation, it being possible, depending on technical expenditure, to separate off either almost isomerically pure fractions with proportions of 4,4'-MDI, for example, of more than 97.5 wt.%, or isomer mixtures with proportions of 4,4'-MDI and 2,4'-MDI of about 50 wt.% in each case.
BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 In the past, because of technical conditions, pure 2,4' isomer was commercially available only in very limited quantities, if at all. Recently, however, more effort has been devoted to making this isomer available in high purity as well.
A basic reason for this effort is the differences in reactivity of the 2- and 4'-NCO
groups of 2,4'-MDI, in a similar way to the differences in reactivity of the 2-and 4-NCO groups of 2,4-toluylene diisocyanate (TDI).
These differences in reactivity allow or facilitate the synthesis of monomer-poor NCO
prepolymers. NCO prepolymers are polyols with terminal NCO groups which are obtained by reacting a polyol with a polyisocyanate using a molar excess of NCO, based on the NCO-reactive groups, at room temperature to about 100 C.
Depending on the initial molar proportions, NCO prepolymers prepared in this way always contain free monomeric diisocyanate.
In the case of 2,4-TDI, the driving force behind the preparation of monomer-poor to practically monomer-free NCO prepolymers is justified by its high vapour pressure and the resulting health hazards. NCO prepolymers based on aliphatic diisocyanates, e.g. hexamethylene diisocyanate (HDI) or isophorone diisocyanate (IPDI), are to be regarded as even more critical in this context. This aspect is also relevant to MDI, although to a markedly reduced extent because its vapour pressure is lower than that of TDI. Moreover, reducing the monomer content of the prepolymer results in polyurethanes that are softer than those prepared from monomer-containing NCO
prepolymers.
Monomer-poor NCO prepolymers can be prepared in several different ways:
a.) Removal of the free monomeric diisocyanate by technically expensive film evaporation or short-path evaporation. This is independent of whether the BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 diisocyanates used have NCO groups of the same or different reactivity.
Entraining agents, for example, can also be used for this purpose.
b.) Use of diisocyanates with NCO groups of different reactivity or NCO groups of the same reactivity, and specially chosen stoichiometric proportions, e.g.
molar proportions of NCO to NCO-reactive groups of less than 2:1, and/or optionally under special catalysis.
c.) Combinations of both processes, e.g. in such a way that the proportion of free monomeric diisocyanate is initially limited to a certain extent by process b.) and then minimized further by process a.).
Such combinations can be useful when the viscosity of the prepolymers is to be minimized. The disadvantage of process b.) is basically that reactions with stoichio-metric proportions particularly of less than 2:1 lead to increased pre-extension, inherently resulting in a marked increase in the viscosity of the reaction product.
WO 01 /40340 A2 (Crompton Corp.) gives examples of such combinations wherein, in a first step, the diisocyanate is converted to an NCO prepolymer with the concomitant use of a selectivity-increasing catalyst, and said prepolymer is then freed of excess monomer by film evaporation.
Particularly critical applications, for instance in the food sector, are affected by the matter of industrial hygiene, which applies to a high degree to TDI and also to MDI.
This is indicated by numerous patents dealing even with monomer-poor MDI
prepolymers, e.g. WO 03/006521 (Henkel KGaA), WO 03/033562 (Henkel KGaA), WO 03/055929 (Henkel KGaA), WO 03/051951 (Henkel KGaA), WO 93/09158 (Bayer AG) and EP 0 693 511 A l(Bayer AG).
The object of the present invention was therefore to provide polyurethanes based on 2,4'-MDI which have processing advantages compared with the state of the art, for instance in the form of longer casting times and lower prepolymer viscosities, and at BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 the same time are at least equal to the state of the art in terms of their mechanical properties.
Surprisingly, it has now been found that, in terms of mechanical properties (e.g.
abrasion, ultimate strength, tear propagation resistance, elongation at break), valuable PUR are obtained from NCO prepolymers based on 2,4'-MDI with a 2,4' isomer content of at least 85 wt.% and a proportion of free monomeric MDI in the prepolymer of at least 1 wt.% to 20 wt.%, preferably of at least 2 wt.% to 18 wt.% and particularly preferably of 3 to 15 wt.%, based on the prepolymer. The low viscosity of the NCO prepolymers is a further advantage.
NCO prepolymers are understood hereafter as meaning NCO prepolymers which have been prepared from pure 2,4'-MDI, contain at least I wt.% and max. 20 wt.% of free monomeric diisocyanate, based on the prepolymer, and have not been extracted or distilled.
Pure 2,4'-MDI is understood hereafter as meaning MDI grades which have a 2,4' isomer content of at least 85 wt.%, preferably of at least 90 wt.%, particularly preferably of at least 95 wt.% and very particularly preferably of at least 97.5 wt.%.
The present invention provides polyurethane elastomers obtainable (by the casting process) from a) NCO prepolymers based on diphenylmethane diisocyanate with a 2,4' isomer content of at least 85 wt.%, preferably of at least 90 wt.%, particularly preferably of at least 95 wt.% and very particularly preferably of at least 97.5 wt.%, the proportion of free monomeric 2,4'-MDI being at least I wt.% to 20 wt.%, preferably 2 to 18 wt.% and particularly preferably 3 to 15 wt.%, based on the NCO prepolymer, and polyols having OH numbers of 20 to 200 mg KOH/g and functionalities of 1.95 to 2.40, preferably of 1.96 to 2.20, BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 b) amine-based chain extenders and/or crosslinking agents, preferably aromatic amine-based chain extenders and/or crosslinking agents, and c) optionally auxiliary substances and additives.
The polyurethanes according to the invention are superior to the state of the art because they have particularly favourable combinations of advantageous properties in respect of prepolymer viscosity, casting time and mechanical and mechanico-dynamic properties.
The invention also provides a casting process for the preparation of the polyurethane elastomers according to the invention, said process being characterized in that A) diphenylmethane diisocyanate (MDI) with a 2,4' isomer content of at least wt.%, preferably of at least 90 wt.%, particularly preferably of at least 95 wt.% and very particularly preferably of at least 97.5 wt.% is reacted with polyols having OH numbers of 20 to 200 mg KOH/g and functionalities of 1.95 to 2.40 to give NCO prepolymers with a proportion of free monomeric 2,4'-MDI of I wt.% to 20 wt.%, preferably of 2 to 18 wt.% and particularly preferably of 3 to 15 wt.%, based on the NCO prepolymer, and B) amine-based chain extenders and/or crosslinking agents and optionally auxiliary substances and additives are added to the prepolymer from A) in order to prepare the elastomer.
The preparation of elastomers by the casting process is a generally important use of NCO-terminated prepolymers, the NCO prepolymers either being reacted with a chain extender directly after their preparation or being cooled to a lower temperature (storage temperature) and stored for the purpose of chain extension at a later stage.
BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 The synthetic route via prepolymers is favourable in that part of the heat of reaction is already produced during the synthesis of the prepolymer, thereby reducing the exothermicity of the actual polymer synthesis. This has a favourable effect on the rate of molecular weight build-up and allows longer casting times, representing a processing advantage.
In one particularly preferred embodiment of the preparation of the PUR
elastomers by the prepolymer process, the prepolymers are first degassed by the application of a reduced pressure at room temperature or elevated temperature, and then stirred with a chain extender, usually at elevated temperature.
In the process according to the invention, the prepolymer is preferably heated to a temperature of 60 C to 1] 0 C and degassed under vacuum, with stirring. The chain extender and/or crosslinking agent is then added in liquid form, optionally after having been heated to temperatures typically of at least 5 C above its melting point.
The reaction mixture is cast into preheated moulds (preferably 90 C to 120 C) and cured at 90 C to 140 C for about 24 hours.
Polyols which can be used are polyether-, polyester-, polycarbonate- and polyetheresterpolyols having hydroxyl numbers of 20 to 200 mg KOH/g, preferably of 27 to 150 and particularly preferably of 27 to 120.
Polyetherpolyols are prepared from an initiator molecule and epoxides, preferably ethylene oxide and/or propylene oxide, by means of either alkaline catalysis or double metal cyanide catalysis, or optionally by means of alkaline catalysis and double metal cyanide catalysis in a stepwise reaction, and have terminal hydroxyl groups.
Initiators which can be used here are the compounds with hydroxyl and/or amino groups known to those skilled in the art, and water. The functionality of the initiators is at least 2 and at most 4. Of course, it is also possible to use mixtures of several initiators.
BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 Mixtures of several polyetherpolyols can also be used. Polyetherpolyols can be tetrahydrofuran oligomers with terminal hydroxyl groups.
Polyesterpolyols are prepared in a manner known per se by the polycondensation of aliphatic and/or aromatic polycarboxylic acids having 4 to 16 carbon atoms, optionally their anhydrides and optionally their low-molecular esters, including cyclic esters, the reaction component used being predominantly low-molecular polyols having 2 to carbon atoms. The functionality of the structural components for polyesterpolyols is preferably 2, but can also be greater than 2 in individual cases, the components having functionalities greater than 2 only being used in small amounts so that the arithmetic number-average functionality of the polyesterpolyols ranges from 2 to 2.5, preferably from2to2.1.
Polyetheresterpolyols are prepared by the concomitant use of polyetherpolyols in the synthesis of polyesterpolyols.
Polycarbonatepolyols are obtained according to the state of the art by the polycondensation of carbonic acid derivatives, e.g. dimethyl or diphenyl carbonate or phosgene, and polyols.
Preferred chain extenders are aromatic amine-based chain extenders, e.g.
diethyl-toluenediamine (DETDA), 3,3'-dichloro-4,4'-diaminodiphenylmethane (MBOCA), isobutyl 3,5-diamino-4-chlorobenzoate, 4-methyl-2,6-bis(methylthio)-1,3-diamino-benzene (Ethacure 300), trimethylene glycol di-p-aminobenzoate (Polacure 740M) and 4,4'-diamino-2,2'-dichloro-5,5'-diethyldiphenylmethane (MCDEA). MBOCA
and isobutyl 3,5-diamino-4-chlorobenzoate are particularly preferred.
Aliphatic amine-based chain extenders can likewise be used (concomitantly).
It is also possible to use auxiliary substances and additives, for instance catalysts, stabilizers, UV stabilizers, hydrolysis stabilizers, emulsifiers, and dyestuffs and coloured pigments that are preferably capable of incorporation.
BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 -g-Examples of catalysts are trialkylamines, diazabicyclooctane, tin dioctanoate, dibutyltin dilaurate, N-alkylmorpholine, lead, zinc, calcium or magnesium octanoate and the corresponding naphthenates and p-nitrophenate.
Examples of stabilizers are Broensted and Lewis acids, for instance hydrochloric acid, benzoyl chloride, organomineral acids, e.g. dibutyl phosphate, and also adipic acid, malic acid, succinic acid, tartaric acid or citric acid.
Examples of UV stabilizers and hydrolysis stabilizers are 2,6-dibutyl-4-methylphenol and sterically hindered carbodiimides.
Dyestuffs capable of incorporation are those which possess Zerewitinoff-active hydrogen atoms, i.e. which can react with NCO groups.
Other auxiliary substances and additives include emulsifiers, foam stabilizers, cell regulators and fillers. A survey can be found in G. Oertel, Polyurethane Handbook, 2nd edition, Carl Hanser Verlag, Munich, 1994, chap. 3.4.
The polyurethane elastomers according to the invention can be used in a very wide variety of applications, e.g. as elastic mouldings produced by the casting process, as well as in coatings and adhesive bonds produced by a spraying process, as e.g.
in parking deck coating systems, concrete repairs and corrosion protection.
The invention will be illustrated in greater detail with the aid of the Examples which follow.
BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 Examples Methods of measurement used:
Property Dimensions DIN standard ISO/ASTM standard Hardness [Shore] DIN 53505 ISO 868 Stress [MPa] DIN 53504 ISO 527 Ultimate strength [MPa] DIN 53504 ISO 527 Elongation at break [%] DIN 53504 ISO 527 Tear propagation resistance [kN/m] DIN 53515 ISO 527 Abrasion [mm3] DIN 53516 ASTM D 1242 Density [g/mm3] DIN 53420 ISO 1183 Permanent set, PS [%] DIN 53517 DIN ISO 815 Chemicals used:
Polyesterpolyol 1: poly(ethylene-co-butylene) adipate having an OH number of mg KOH/g from Bayer MaterialScience AG; nominal functionality 2.0;
4,4'-MDI: 4,4'-diphenylmethane diisocyanate, Desmodur 44M from Bayer MaterialScience AG; 98.5 wt.% of 4,4' isomer;
2,4'-MDI: 2,4'-diphenylmethane diisocyanate (laboratory product) from Bayer MaterialScience AG; 98.5 wt.% of 2,4' isomer;
Isobutyl 3,5-diamino-4-chlorobenzoate: RC-Crosslinker 1604 from Rheinchemie, Rheinau.
BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 Example 1: Preparation of MDI-based ester prepolymers Instructions for the preparation of prepolymers using prepolymer 2 as an example (Table 1):
25 parts by weight of 2,4'-MDI were heated to 70 C in a stirred flask under nitrogen and stirred rapidly with 100 parts by weight of dehydrated polyesterpolyol 1 heated to 70 C. The reaction was allowed to proceed for 2 hours and the physical properties were determined (cf. Table 1).
Table 1: Formulations of MDI-based ester prepolymers (according to the invention and Comparative Examples) Polyesterpolyol I [parts by weight] 100 100 Prepolymer I [parts by weight] 100 100 Prepolymer 2 [parts by weight] l00 100 4,4'-MDI [parts by weight] 25 10 10 2,4'-MDI [parts by weight] 25 10 10 NCO (theoret.) [wt.% of NCO] 3.36 3.36 6.1 6.1 6.1 6.1 NCO (exp.) [wt.% of NCO] 3.4 3.44 6.2 6.1 6.17 6.15 Free MDI [wt.%] 4.8 3.1 11.9 13.4 11.9 13.4 Viscosity at 70 C [mPas] 10,600 4800 2900 6200 2900 6400 C: Comparison Prepolymer 1: from 100 parts by weight of polyesterpolyol I and 25 parts by weight of 4,4'-MDI
BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 Prepolymer 2: from 100 parts by weight of polyesterpolyol I and 25 parts by weight of 2,4'-MDI
Comparison of the viscosity values for MDI prepolymers with a theoretical NCO
content of 3.36 wt.% shows the advantages of the prepolymer based on 2,4'-MDI
(prepolymer 2, according to the invention) over the 4,4' analogue (prepolymer 1 C, not according to the invention).
Mixing of these two prepolymers with additional MDI to NCO contents of 6.1 wt.%
of NCO (theoret.) obviously gives in all cases prepolymers with lower viscosities than the starting prepolymers (prepolymers 3 C, 4 C, 5 and 6 C in Table 1). It is further seen that the equally low viscosity of prepolymers 3 C and 5 (in each case 2900 mPas at 70 C) is not sufficient for advantageous processing (e.g. casting time) to casting elastomers. Only prepolymer 5 could advantageously be processed further to an elastomer (cf. Tables 2 and 3).
Example 2: Preparation of casting elastomers according to the invention from prepolymers 2 and 5 of Example l Instructions for the preparation of casting elastomers using casting elastomer A
as an example:
100 parts of prepolymer 2 were degassed at 90 C under vacuum, with slow stirring, until free of bubbles. This was then stirred with 9.05 parts of isobutyl 3,5-diamino-4-chlorobenzoate preheated to 100 C, and the reacting homogeneous melt was cast into moulds preheated to 110 C, having dimensions corresponding to the testing standards.
The melt was then heated for 24 hours at 1 l0 C and the mechanical properties listed in Table 2 were determined.
BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 Table 2: Formulations, preparation and properties of the casting elastomers according to the invention Casting elastomer No. A B C D E
Formulation and preparation:
No. 2 2 2 2 5 Prepolymer [parts by 100 80 60 40 100 weight]
No. 5 5 5 Prepolymer [parts by 20 40 60 weight]
NCO (theoret.) [wt.% of NCO] 3.36 3.9 4.46 5.04 6.1 Prepolymer temperature [ C] 90 90 90 90 85 Viscosity of prepolymer [mPas] 2030 1940 1750 1600 1200 mixture, 90 C
Isobutyl 3,5-diamino-4- [parts by 9.05 10.5 12.0 13.6 16.4 chlorobenzoate weight]
Temperature of [ C] 100 100 100 100 100 crosslinking agent Index (theoret.) 107 107 107 107 107 Casting time [s] 225 165 105 105 60 Peeling time [min] 8 8 7 7 5 Mould temperature [ C] 110 ]10 110 110 110 Post-heating temperature [ C] 110 110 110 110 110 Post-heating time [h] 24 24 24 24 24 Mechanical properties:
Hardness [Shore A] 91 92 93 97 99 [Shore D] 37 49 Stress 10% [MPa] 3.61 4.22 5.26 6.45 9.23 Stress 100% [MPa] 6.5 6.9 7.5 8.3 10.0 Stress 300% [MPa] 9.9 10.0 11.4 12.0 14.3 Ultimate strength [MPa] 43.31 36.3 44.4 42.6 46.0 Elongation at break [%] 683 607 591 616 609 Tear propagation [kN/m] 62.8 67.3 71.6 83 99.2 resistance, Graves Impact resilience [%] 47 47 Abrasion (DIN) [mm3] 59 57 62 52 Density [g/mm3] 1.214 1.218 1.224 1.214 BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 PS 22 C [%] 25.4 64 36.7 PS 70 C [%] 47.4 61 56.4 at 0 C 36.0 48.4 70.6 86.5 139 Storage modulus G' at 20 C 28.2 36.9 53.3 65.9 108 [MPa] at 50 C 24.6 31.2 43.9 53.1 84.8 at 80 C 24.3 29.4 41.0 47.4 74.9 at 110 C 25.5 29.6 40.7 45.5 70.2 at 0 C 0.1302 0.1246 0.1170 0.1045 0.0903 Loss factor, tan S at 20 C 0.0768 0.0789 0.0756 0.0734 0.0690 at 50 C 0.0484 0.0494 0.0497 0.0542 0.0543 at 80 C 0.0302 0.0318 0.0318 0.0392 0.0389 at 110 C 0.0177 0.0193 0.0193 0.0259 0.0270 tan S max. -36 -36 -36 -36 -36 tan 5 min. 130 130 130 130 130 at 0 C 4.69 6.0 8.26 9.04 12.5 at 20 C 2.16 2.9 4.03 4.84 7.46 Loss modulus G" [MPa] at 50 C 1.19 1.5 2.18 2.88 4.61 at 80 C 0.74 0.9 1.30 1.86 2.91 at 110 C 0.45 0.6 0.79 1.18 1.89 Softening point [ C] 190 195 195 210 195 Example 3: Preparation of casting elastomers not according to the invention from prepolymers I C, 3 C, 4 C and 6 C of Example I
The preparation was carried out as described under Example 2.
BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 Table 3: Formulations, preparation and properties of the casting elastomers not according to the invention Casting elastomer No. F G H 1 Formulation and preparation:
Prepolymer No. 1 C 3 C 4 C 6 C
[parts by 100 100 100 100 weight]
NCO (theoret.) [wt.% of NCO] 3.36 6.1 6.1 6.1 Prepolymer temperature [ C] l00 90 90 90 Viscosity of prepolymer, [mPas] 4530 1200 2710 2720 Isobutyl 3,5-diamino-4- [parts by 9.05 16.4 16.4 16.4 chlorobenzoate weight]
Temperature of [ C] 100 100 100 100 crosslinking agent Index (theoret.) 107 107 107 107 Casting time [s] 75 30 60 60 Peeling time [min] 9 4 3 4 Mould temperature [ C] 110 110 110 110 Post-heating temperature [ C] 110 110 110 110 Post-heating time [h] 24 24 24 24 Mechanical properties:
Hardness [Shore A] 83 99 99 99 [Shore D] 31 49 48 48 Stress 10% [MPa] 1.92 9.91 9.09 8.45 Stress 100% [MPa] 4.0 10.2 9.06 8.6 Stress 300% [MPa] 8.8 16.0 13.8 12.3 Ultimate strength [MPa] 10.3 51.5 35.1 33 Elongation at break [%] 325 538 543 589 Tear propagation [kN/m] 14.9 89.6 89.5 87.8 resistance, Graves Impact resilience [%] 50 48 47 46 Abrasion (DIN) [mm3] 101 69 46 55 Density [g/mm3] 1.205 1.228 1.228 1.228 PS 22 C [%] 8.5 45.9 45.1 47 PS 70 C [%] 16.2 66.8 57.8 67.4 BMS 05 1 055-WO-Nat ! WO 2007/087987 PCT/EP2007/000446 at 0 C 16.6 177 140.4 138.8 Storage modulus G' at 20 C 14.6 137 110.5 101.8 [MPa] at 50 C 15.0 107 87.6 78.0 at 80 C 15.8 94.0 78.7 66.2 at 110 C 16.2 87.2 74.8 60.8 at 0 C 0.1295 0.0870 0.0807 0.0976 at 20 C 0.0428 0.0665 0.0605 0.0735 Loss factor, tan S at 50 C 0.0169 0.0544 0.0468 0.0616 at 80 C 0.0097 0.0417 0.0358 0.0488 at 110 C 0.0075 0.0309 0.0231 0.0352 tan S max. -33 -36 -36 -33 tan S min. 110 130 190 140 at 0 C 2.15 15 11.32 13.55 at 20 C 0.63 9.08 6.68 7.48 Loss modulus G" [MPa] at 50 C 0.25 5.81 4.10 4.81 at 80 C 0.15 3.92 2.82 3.23 at 110 C 0.12 2.69 1.73 2.14 Softening point [ C] 165 195 230 200 The advantages of the systems according to the invention are made clear by comparing Tables 2 and 3:
At comparable prepolymer temperatures (starting temperature) and comparable NCO
contents, i.e. comparable formulations, the casting times of the prepolymers according to the invention (Table 2) are up to 3 times longer than those of the systems not according to the invention (Table 3), which represents a clear processing advantage.
The particularly favourable combinations of the properties of "long casting time" and "low prepolymer viscosity" are only achieved by the systems according to the invention.
The casting elastomers according to the invention also exhibit advantages in respect of their mechanical properties:
BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 -]6-If, for example, the PUR prepared from prepolymer 2 (casting elastomer A, Table 2) is compared with a PUR prepared from prepolymer I C (casting elastomer F, Table 3) - both prepolymers having the same NCO value of 3.36 wt.% of NCO - the system according to the invention has a better ultimate strength, elongation at break, tear propagation resistance and abrasion.
If the PUR prepared from prepolymer 5 (casting elastomer E, Table 2) is compared with a PUR prepared from prepolymers 3 C, 4 C and 6 C (casting elastomers G, H
and I, Table 3) - all the prepolymers having the same NCO value of 6.1 wt.% of NCO
-the system according to the invention has a comparably good ultimate strength, elongation at break, tear propagation resistance, abrasion and permanent set, within the limits of experimental error.
The same also applies in terms of the mechanico-dynamic properties (storage and loss moduli and loss factor).
The systems according to the invention exhibit a unique combination of advantageous properties in respect of prepolymer viscosity, casting time and mechanical and mechanico-dynamic properties.
MDI (diphenylmethane diisocyanate) is a technically important group of poly-isocyanates; it has a very heterogeneous composition in terms of its structure and comprises monomer grades characterized in that they have two aromatic structural elements bonded via a single methylene bridge, and higher oligomers having more than two aromatic structural elements and possessing more than one methylene bridge, which are referred to as polymeric MDI.
Monomeric MDI contains predominantly the 4,4' and 2,4' isomers as a consequence of its synthesis. The 2,2' isomer also occurs to a lesser extent, but is largely of no technical value.
The ratio of monomeric MDI to polymeric MDI, and the proportions of the 2,4' and 4,4' isomers in monomeric MDI, can be varied within wide limits by varying the conditions of synthesis of the precursor.
The crude MDI obtained in the MDI synthesis is separated substantially by distillation, it being possible, depending on technical expenditure, to separate off either almost isomerically pure fractions with proportions of 4,4'-MDI, for example, of more than 97.5 wt.%, or isomer mixtures with proportions of 4,4'-MDI and 2,4'-MDI of about 50 wt.% in each case.
BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 In the past, because of technical conditions, pure 2,4' isomer was commercially available only in very limited quantities, if at all. Recently, however, more effort has been devoted to making this isomer available in high purity as well.
A basic reason for this effort is the differences in reactivity of the 2- and 4'-NCO
groups of 2,4'-MDI, in a similar way to the differences in reactivity of the 2-and 4-NCO groups of 2,4-toluylene diisocyanate (TDI).
These differences in reactivity allow or facilitate the synthesis of monomer-poor NCO
prepolymers. NCO prepolymers are polyols with terminal NCO groups which are obtained by reacting a polyol with a polyisocyanate using a molar excess of NCO, based on the NCO-reactive groups, at room temperature to about 100 C.
Depending on the initial molar proportions, NCO prepolymers prepared in this way always contain free monomeric diisocyanate.
In the case of 2,4-TDI, the driving force behind the preparation of monomer-poor to practically monomer-free NCO prepolymers is justified by its high vapour pressure and the resulting health hazards. NCO prepolymers based on aliphatic diisocyanates, e.g. hexamethylene diisocyanate (HDI) or isophorone diisocyanate (IPDI), are to be regarded as even more critical in this context. This aspect is also relevant to MDI, although to a markedly reduced extent because its vapour pressure is lower than that of TDI. Moreover, reducing the monomer content of the prepolymer results in polyurethanes that are softer than those prepared from monomer-containing NCO
prepolymers.
Monomer-poor NCO prepolymers can be prepared in several different ways:
a.) Removal of the free monomeric diisocyanate by technically expensive film evaporation or short-path evaporation. This is independent of whether the BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 diisocyanates used have NCO groups of the same or different reactivity.
Entraining agents, for example, can also be used for this purpose.
b.) Use of diisocyanates with NCO groups of different reactivity or NCO groups of the same reactivity, and specially chosen stoichiometric proportions, e.g.
molar proportions of NCO to NCO-reactive groups of less than 2:1, and/or optionally under special catalysis.
c.) Combinations of both processes, e.g. in such a way that the proportion of free monomeric diisocyanate is initially limited to a certain extent by process b.) and then minimized further by process a.).
Such combinations can be useful when the viscosity of the prepolymers is to be minimized. The disadvantage of process b.) is basically that reactions with stoichio-metric proportions particularly of less than 2:1 lead to increased pre-extension, inherently resulting in a marked increase in the viscosity of the reaction product.
WO 01 /40340 A2 (Crompton Corp.) gives examples of such combinations wherein, in a first step, the diisocyanate is converted to an NCO prepolymer with the concomitant use of a selectivity-increasing catalyst, and said prepolymer is then freed of excess monomer by film evaporation.
Particularly critical applications, for instance in the food sector, are affected by the matter of industrial hygiene, which applies to a high degree to TDI and also to MDI.
This is indicated by numerous patents dealing even with monomer-poor MDI
prepolymers, e.g. WO 03/006521 (Henkel KGaA), WO 03/033562 (Henkel KGaA), WO 03/055929 (Henkel KGaA), WO 03/051951 (Henkel KGaA), WO 93/09158 (Bayer AG) and EP 0 693 511 A l(Bayer AG).
The object of the present invention was therefore to provide polyurethanes based on 2,4'-MDI which have processing advantages compared with the state of the art, for instance in the form of longer casting times and lower prepolymer viscosities, and at BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 the same time are at least equal to the state of the art in terms of their mechanical properties.
Surprisingly, it has now been found that, in terms of mechanical properties (e.g.
abrasion, ultimate strength, tear propagation resistance, elongation at break), valuable PUR are obtained from NCO prepolymers based on 2,4'-MDI with a 2,4' isomer content of at least 85 wt.% and a proportion of free monomeric MDI in the prepolymer of at least 1 wt.% to 20 wt.%, preferably of at least 2 wt.% to 18 wt.% and particularly preferably of 3 to 15 wt.%, based on the prepolymer. The low viscosity of the NCO prepolymers is a further advantage.
NCO prepolymers are understood hereafter as meaning NCO prepolymers which have been prepared from pure 2,4'-MDI, contain at least I wt.% and max. 20 wt.% of free monomeric diisocyanate, based on the prepolymer, and have not been extracted or distilled.
Pure 2,4'-MDI is understood hereafter as meaning MDI grades which have a 2,4' isomer content of at least 85 wt.%, preferably of at least 90 wt.%, particularly preferably of at least 95 wt.% and very particularly preferably of at least 97.5 wt.%.
The present invention provides polyurethane elastomers obtainable (by the casting process) from a) NCO prepolymers based on diphenylmethane diisocyanate with a 2,4' isomer content of at least 85 wt.%, preferably of at least 90 wt.%, particularly preferably of at least 95 wt.% and very particularly preferably of at least 97.5 wt.%, the proportion of free monomeric 2,4'-MDI being at least I wt.% to 20 wt.%, preferably 2 to 18 wt.% and particularly preferably 3 to 15 wt.%, based on the NCO prepolymer, and polyols having OH numbers of 20 to 200 mg KOH/g and functionalities of 1.95 to 2.40, preferably of 1.96 to 2.20, BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 b) amine-based chain extenders and/or crosslinking agents, preferably aromatic amine-based chain extenders and/or crosslinking agents, and c) optionally auxiliary substances and additives.
The polyurethanes according to the invention are superior to the state of the art because they have particularly favourable combinations of advantageous properties in respect of prepolymer viscosity, casting time and mechanical and mechanico-dynamic properties.
The invention also provides a casting process for the preparation of the polyurethane elastomers according to the invention, said process being characterized in that A) diphenylmethane diisocyanate (MDI) with a 2,4' isomer content of at least wt.%, preferably of at least 90 wt.%, particularly preferably of at least 95 wt.% and very particularly preferably of at least 97.5 wt.% is reacted with polyols having OH numbers of 20 to 200 mg KOH/g and functionalities of 1.95 to 2.40 to give NCO prepolymers with a proportion of free monomeric 2,4'-MDI of I wt.% to 20 wt.%, preferably of 2 to 18 wt.% and particularly preferably of 3 to 15 wt.%, based on the NCO prepolymer, and B) amine-based chain extenders and/or crosslinking agents and optionally auxiliary substances and additives are added to the prepolymer from A) in order to prepare the elastomer.
The preparation of elastomers by the casting process is a generally important use of NCO-terminated prepolymers, the NCO prepolymers either being reacted with a chain extender directly after their preparation or being cooled to a lower temperature (storage temperature) and stored for the purpose of chain extension at a later stage.
BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 The synthetic route via prepolymers is favourable in that part of the heat of reaction is already produced during the synthesis of the prepolymer, thereby reducing the exothermicity of the actual polymer synthesis. This has a favourable effect on the rate of molecular weight build-up and allows longer casting times, representing a processing advantage.
In one particularly preferred embodiment of the preparation of the PUR
elastomers by the prepolymer process, the prepolymers are first degassed by the application of a reduced pressure at room temperature or elevated temperature, and then stirred with a chain extender, usually at elevated temperature.
In the process according to the invention, the prepolymer is preferably heated to a temperature of 60 C to 1] 0 C and degassed under vacuum, with stirring. The chain extender and/or crosslinking agent is then added in liquid form, optionally after having been heated to temperatures typically of at least 5 C above its melting point.
The reaction mixture is cast into preheated moulds (preferably 90 C to 120 C) and cured at 90 C to 140 C for about 24 hours.
Polyols which can be used are polyether-, polyester-, polycarbonate- and polyetheresterpolyols having hydroxyl numbers of 20 to 200 mg KOH/g, preferably of 27 to 150 and particularly preferably of 27 to 120.
Polyetherpolyols are prepared from an initiator molecule and epoxides, preferably ethylene oxide and/or propylene oxide, by means of either alkaline catalysis or double metal cyanide catalysis, or optionally by means of alkaline catalysis and double metal cyanide catalysis in a stepwise reaction, and have terminal hydroxyl groups.
Initiators which can be used here are the compounds with hydroxyl and/or amino groups known to those skilled in the art, and water. The functionality of the initiators is at least 2 and at most 4. Of course, it is also possible to use mixtures of several initiators.
BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 Mixtures of several polyetherpolyols can also be used. Polyetherpolyols can be tetrahydrofuran oligomers with terminal hydroxyl groups.
Polyesterpolyols are prepared in a manner known per se by the polycondensation of aliphatic and/or aromatic polycarboxylic acids having 4 to 16 carbon atoms, optionally their anhydrides and optionally their low-molecular esters, including cyclic esters, the reaction component used being predominantly low-molecular polyols having 2 to carbon atoms. The functionality of the structural components for polyesterpolyols is preferably 2, but can also be greater than 2 in individual cases, the components having functionalities greater than 2 only being used in small amounts so that the arithmetic number-average functionality of the polyesterpolyols ranges from 2 to 2.5, preferably from2to2.1.
Polyetheresterpolyols are prepared by the concomitant use of polyetherpolyols in the synthesis of polyesterpolyols.
Polycarbonatepolyols are obtained according to the state of the art by the polycondensation of carbonic acid derivatives, e.g. dimethyl or diphenyl carbonate or phosgene, and polyols.
Preferred chain extenders are aromatic amine-based chain extenders, e.g.
diethyl-toluenediamine (DETDA), 3,3'-dichloro-4,4'-diaminodiphenylmethane (MBOCA), isobutyl 3,5-diamino-4-chlorobenzoate, 4-methyl-2,6-bis(methylthio)-1,3-diamino-benzene (Ethacure 300), trimethylene glycol di-p-aminobenzoate (Polacure 740M) and 4,4'-diamino-2,2'-dichloro-5,5'-diethyldiphenylmethane (MCDEA). MBOCA
and isobutyl 3,5-diamino-4-chlorobenzoate are particularly preferred.
Aliphatic amine-based chain extenders can likewise be used (concomitantly).
It is also possible to use auxiliary substances and additives, for instance catalysts, stabilizers, UV stabilizers, hydrolysis stabilizers, emulsifiers, and dyestuffs and coloured pigments that are preferably capable of incorporation.
BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 -g-Examples of catalysts are trialkylamines, diazabicyclooctane, tin dioctanoate, dibutyltin dilaurate, N-alkylmorpholine, lead, zinc, calcium or magnesium octanoate and the corresponding naphthenates and p-nitrophenate.
Examples of stabilizers are Broensted and Lewis acids, for instance hydrochloric acid, benzoyl chloride, organomineral acids, e.g. dibutyl phosphate, and also adipic acid, malic acid, succinic acid, tartaric acid or citric acid.
Examples of UV stabilizers and hydrolysis stabilizers are 2,6-dibutyl-4-methylphenol and sterically hindered carbodiimides.
Dyestuffs capable of incorporation are those which possess Zerewitinoff-active hydrogen atoms, i.e. which can react with NCO groups.
Other auxiliary substances and additives include emulsifiers, foam stabilizers, cell regulators and fillers. A survey can be found in G. Oertel, Polyurethane Handbook, 2nd edition, Carl Hanser Verlag, Munich, 1994, chap. 3.4.
The polyurethane elastomers according to the invention can be used in a very wide variety of applications, e.g. as elastic mouldings produced by the casting process, as well as in coatings and adhesive bonds produced by a spraying process, as e.g.
in parking deck coating systems, concrete repairs and corrosion protection.
The invention will be illustrated in greater detail with the aid of the Examples which follow.
BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 Examples Methods of measurement used:
Property Dimensions DIN standard ISO/ASTM standard Hardness [Shore] DIN 53505 ISO 868 Stress [MPa] DIN 53504 ISO 527 Ultimate strength [MPa] DIN 53504 ISO 527 Elongation at break [%] DIN 53504 ISO 527 Tear propagation resistance [kN/m] DIN 53515 ISO 527 Abrasion [mm3] DIN 53516 ASTM D 1242 Density [g/mm3] DIN 53420 ISO 1183 Permanent set, PS [%] DIN 53517 DIN ISO 815 Chemicals used:
Polyesterpolyol 1: poly(ethylene-co-butylene) adipate having an OH number of mg KOH/g from Bayer MaterialScience AG; nominal functionality 2.0;
4,4'-MDI: 4,4'-diphenylmethane diisocyanate, Desmodur 44M from Bayer MaterialScience AG; 98.5 wt.% of 4,4' isomer;
2,4'-MDI: 2,4'-diphenylmethane diisocyanate (laboratory product) from Bayer MaterialScience AG; 98.5 wt.% of 2,4' isomer;
Isobutyl 3,5-diamino-4-chlorobenzoate: RC-Crosslinker 1604 from Rheinchemie, Rheinau.
BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 Example 1: Preparation of MDI-based ester prepolymers Instructions for the preparation of prepolymers using prepolymer 2 as an example (Table 1):
25 parts by weight of 2,4'-MDI were heated to 70 C in a stirred flask under nitrogen and stirred rapidly with 100 parts by weight of dehydrated polyesterpolyol 1 heated to 70 C. The reaction was allowed to proceed for 2 hours and the physical properties were determined (cf. Table 1).
Table 1: Formulations of MDI-based ester prepolymers (according to the invention and Comparative Examples) Polyesterpolyol I [parts by weight] 100 100 Prepolymer I [parts by weight] 100 100 Prepolymer 2 [parts by weight] l00 100 4,4'-MDI [parts by weight] 25 10 10 2,4'-MDI [parts by weight] 25 10 10 NCO (theoret.) [wt.% of NCO] 3.36 3.36 6.1 6.1 6.1 6.1 NCO (exp.) [wt.% of NCO] 3.4 3.44 6.2 6.1 6.17 6.15 Free MDI [wt.%] 4.8 3.1 11.9 13.4 11.9 13.4 Viscosity at 70 C [mPas] 10,600 4800 2900 6200 2900 6400 C: Comparison Prepolymer 1: from 100 parts by weight of polyesterpolyol I and 25 parts by weight of 4,4'-MDI
BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 Prepolymer 2: from 100 parts by weight of polyesterpolyol I and 25 parts by weight of 2,4'-MDI
Comparison of the viscosity values for MDI prepolymers with a theoretical NCO
content of 3.36 wt.% shows the advantages of the prepolymer based on 2,4'-MDI
(prepolymer 2, according to the invention) over the 4,4' analogue (prepolymer 1 C, not according to the invention).
Mixing of these two prepolymers with additional MDI to NCO contents of 6.1 wt.%
of NCO (theoret.) obviously gives in all cases prepolymers with lower viscosities than the starting prepolymers (prepolymers 3 C, 4 C, 5 and 6 C in Table 1). It is further seen that the equally low viscosity of prepolymers 3 C and 5 (in each case 2900 mPas at 70 C) is not sufficient for advantageous processing (e.g. casting time) to casting elastomers. Only prepolymer 5 could advantageously be processed further to an elastomer (cf. Tables 2 and 3).
Example 2: Preparation of casting elastomers according to the invention from prepolymers 2 and 5 of Example l Instructions for the preparation of casting elastomers using casting elastomer A
as an example:
100 parts of prepolymer 2 were degassed at 90 C under vacuum, with slow stirring, until free of bubbles. This was then stirred with 9.05 parts of isobutyl 3,5-diamino-4-chlorobenzoate preheated to 100 C, and the reacting homogeneous melt was cast into moulds preheated to 110 C, having dimensions corresponding to the testing standards.
The melt was then heated for 24 hours at 1 l0 C and the mechanical properties listed in Table 2 were determined.
BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 Table 2: Formulations, preparation and properties of the casting elastomers according to the invention Casting elastomer No. A B C D E
Formulation and preparation:
No. 2 2 2 2 5 Prepolymer [parts by 100 80 60 40 100 weight]
No. 5 5 5 Prepolymer [parts by 20 40 60 weight]
NCO (theoret.) [wt.% of NCO] 3.36 3.9 4.46 5.04 6.1 Prepolymer temperature [ C] 90 90 90 90 85 Viscosity of prepolymer [mPas] 2030 1940 1750 1600 1200 mixture, 90 C
Isobutyl 3,5-diamino-4- [parts by 9.05 10.5 12.0 13.6 16.4 chlorobenzoate weight]
Temperature of [ C] 100 100 100 100 100 crosslinking agent Index (theoret.) 107 107 107 107 107 Casting time [s] 225 165 105 105 60 Peeling time [min] 8 8 7 7 5 Mould temperature [ C] 110 ]10 110 110 110 Post-heating temperature [ C] 110 110 110 110 110 Post-heating time [h] 24 24 24 24 24 Mechanical properties:
Hardness [Shore A] 91 92 93 97 99 [Shore D] 37 49 Stress 10% [MPa] 3.61 4.22 5.26 6.45 9.23 Stress 100% [MPa] 6.5 6.9 7.5 8.3 10.0 Stress 300% [MPa] 9.9 10.0 11.4 12.0 14.3 Ultimate strength [MPa] 43.31 36.3 44.4 42.6 46.0 Elongation at break [%] 683 607 591 616 609 Tear propagation [kN/m] 62.8 67.3 71.6 83 99.2 resistance, Graves Impact resilience [%] 47 47 Abrasion (DIN) [mm3] 59 57 62 52 Density [g/mm3] 1.214 1.218 1.224 1.214 BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 PS 22 C [%] 25.4 64 36.7 PS 70 C [%] 47.4 61 56.4 at 0 C 36.0 48.4 70.6 86.5 139 Storage modulus G' at 20 C 28.2 36.9 53.3 65.9 108 [MPa] at 50 C 24.6 31.2 43.9 53.1 84.8 at 80 C 24.3 29.4 41.0 47.4 74.9 at 110 C 25.5 29.6 40.7 45.5 70.2 at 0 C 0.1302 0.1246 0.1170 0.1045 0.0903 Loss factor, tan S at 20 C 0.0768 0.0789 0.0756 0.0734 0.0690 at 50 C 0.0484 0.0494 0.0497 0.0542 0.0543 at 80 C 0.0302 0.0318 0.0318 0.0392 0.0389 at 110 C 0.0177 0.0193 0.0193 0.0259 0.0270 tan S max. -36 -36 -36 -36 -36 tan 5 min. 130 130 130 130 130 at 0 C 4.69 6.0 8.26 9.04 12.5 at 20 C 2.16 2.9 4.03 4.84 7.46 Loss modulus G" [MPa] at 50 C 1.19 1.5 2.18 2.88 4.61 at 80 C 0.74 0.9 1.30 1.86 2.91 at 110 C 0.45 0.6 0.79 1.18 1.89 Softening point [ C] 190 195 195 210 195 Example 3: Preparation of casting elastomers not according to the invention from prepolymers I C, 3 C, 4 C and 6 C of Example I
The preparation was carried out as described under Example 2.
BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 Table 3: Formulations, preparation and properties of the casting elastomers not according to the invention Casting elastomer No. F G H 1 Formulation and preparation:
Prepolymer No. 1 C 3 C 4 C 6 C
[parts by 100 100 100 100 weight]
NCO (theoret.) [wt.% of NCO] 3.36 6.1 6.1 6.1 Prepolymer temperature [ C] l00 90 90 90 Viscosity of prepolymer, [mPas] 4530 1200 2710 2720 Isobutyl 3,5-diamino-4- [parts by 9.05 16.4 16.4 16.4 chlorobenzoate weight]
Temperature of [ C] 100 100 100 100 crosslinking agent Index (theoret.) 107 107 107 107 Casting time [s] 75 30 60 60 Peeling time [min] 9 4 3 4 Mould temperature [ C] 110 110 110 110 Post-heating temperature [ C] 110 110 110 110 Post-heating time [h] 24 24 24 24 Mechanical properties:
Hardness [Shore A] 83 99 99 99 [Shore D] 31 49 48 48 Stress 10% [MPa] 1.92 9.91 9.09 8.45 Stress 100% [MPa] 4.0 10.2 9.06 8.6 Stress 300% [MPa] 8.8 16.0 13.8 12.3 Ultimate strength [MPa] 10.3 51.5 35.1 33 Elongation at break [%] 325 538 543 589 Tear propagation [kN/m] 14.9 89.6 89.5 87.8 resistance, Graves Impact resilience [%] 50 48 47 46 Abrasion (DIN) [mm3] 101 69 46 55 Density [g/mm3] 1.205 1.228 1.228 1.228 PS 22 C [%] 8.5 45.9 45.1 47 PS 70 C [%] 16.2 66.8 57.8 67.4 BMS 05 1 055-WO-Nat ! WO 2007/087987 PCT/EP2007/000446 at 0 C 16.6 177 140.4 138.8 Storage modulus G' at 20 C 14.6 137 110.5 101.8 [MPa] at 50 C 15.0 107 87.6 78.0 at 80 C 15.8 94.0 78.7 66.2 at 110 C 16.2 87.2 74.8 60.8 at 0 C 0.1295 0.0870 0.0807 0.0976 at 20 C 0.0428 0.0665 0.0605 0.0735 Loss factor, tan S at 50 C 0.0169 0.0544 0.0468 0.0616 at 80 C 0.0097 0.0417 0.0358 0.0488 at 110 C 0.0075 0.0309 0.0231 0.0352 tan S max. -33 -36 -36 -33 tan S min. 110 130 190 140 at 0 C 2.15 15 11.32 13.55 at 20 C 0.63 9.08 6.68 7.48 Loss modulus G" [MPa] at 50 C 0.25 5.81 4.10 4.81 at 80 C 0.15 3.92 2.82 3.23 at 110 C 0.12 2.69 1.73 2.14 Softening point [ C] 165 195 230 200 The advantages of the systems according to the invention are made clear by comparing Tables 2 and 3:
At comparable prepolymer temperatures (starting temperature) and comparable NCO
contents, i.e. comparable formulations, the casting times of the prepolymers according to the invention (Table 2) are up to 3 times longer than those of the systems not according to the invention (Table 3), which represents a clear processing advantage.
The particularly favourable combinations of the properties of "long casting time" and "low prepolymer viscosity" are only achieved by the systems according to the invention.
The casting elastomers according to the invention also exhibit advantages in respect of their mechanical properties:
BMS 05 1 055-WO-Nat / WO 2007/087987 PCT/EP2007/000446 -]6-If, for example, the PUR prepared from prepolymer 2 (casting elastomer A, Table 2) is compared with a PUR prepared from prepolymer I C (casting elastomer F, Table 3) - both prepolymers having the same NCO value of 3.36 wt.% of NCO - the system according to the invention has a better ultimate strength, elongation at break, tear propagation resistance and abrasion.
If the PUR prepared from prepolymer 5 (casting elastomer E, Table 2) is compared with a PUR prepared from prepolymers 3 C, 4 C and 6 C (casting elastomers G, H
and I, Table 3) - all the prepolymers having the same NCO value of 6.1 wt.% of NCO
-the system according to the invention has a comparably good ultimate strength, elongation at break, tear propagation resistance, abrasion and permanent set, within the limits of experimental error.
The same also applies in terms of the mechanico-dynamic properties (storage and loss moduli and loss factor).
The systems according to the invention exhibit a unique combination of advantageous properties in respect of prepolymer viscosity, casting time and mechanical and mechanico-dynamic properties.
Claims (5)
1. Polyurethane elastomers obtainable from a.) NCO prepolymers based on diphenylmethane diisocyanate with a 2,4' isomer content of at least 85 wt.%, the proportion of free monomeric
2,4'-MDI being at least 1 to 20 wt.%, based on the NCO prepolymer, and polyols having OH numbers of 20 to 200 mg KOH/g and a functionality of 1.95 to 2.40, b.) amine-based chain extenders and/or crosslinking agents, and c.) optionally auxiliary substances and additives.
2. Polyurethane elastomers according to Claim 1, characterized in that component b) is diethyltoluenediamine (DETDA), 3,3'-dichloro-4,4'-diaminodiphenylmethane (MBOCA), isobutyl 3,5-diamino-4-chlorobenzoate, 4-methyl-2,6-bis(methylthio)-1,3-diaminobenzene (Ethacure 300), trimethylene glycol di-p-aminobenzoate (Polacure 740M) and 4,4'-diamino-2,2'-dichloro-5,5'-diethyldiphenylmethane (MCDEA) or mixtures thereof.
2. Polyurethane elastomers according to Claim 1, characterized in that component b) is diethyltoluenediamine (DETDA), 3,3'-dichloro-4,4'-diaminodiphenylmethane (MBOCA), isobutyl 3,5-diamino-4-chlorobenzoate, 4-methyl-2,6-bis(methylthio)-1,3-diaminobenzene (Ethacure 300), trimethylene glycol di-p-aminobenzoate (Polacure 740M) and 4,4'-diamino-2,2'-dichloro-5,5'-diethyldiphenylmethane (MCDEA) or mixtures thereof.
3. Process for the preparation of the polyurethane elastomers according to Claim 1 or 2, characterized in that A) diphenylmethane diisocyanate with a 2,4' isomer content of at least 85 wt.% is reacted with polyols having OH numbers of 20 to 200 mg KOH/g and functionalities of 1.95 to 2.40 to give NCO
prepolymers with a proportion of free monomeric 2,4'-MDI of 1 wt.%
to 20 wt.%, based on the NCO prepolymer, and B) amine-based chain extenders and/or crosslinking agents and optionally auxiliary substances and additives are added to the prepolymer from A) in order to prepare the elastomer.
prepolymers with a proportion of free monomeric 2,4'-MDI of 1 wt.%
to 20 wt.%, based on the NCO prepolymer, and B) amine-based chain extenders and/or crosslinking agents and optionally auxiliary substances and additives are added to the prepolymer from A) in order to prepare the elastomer.
4. Use of the polyurethane elastomers according to Claim 1 or 2 for the production of mouldings, as adhesives and as sealants.
5. Mouldings obtainable from a polyurethane elastomer according to Claim 1 or 2.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102006004527.0 | 2006-02-01 | ||
| DE102006004527A DE102006004527A1 (en) | 2006-02-01 | 2006-02-01 | Polyurethane cast elastomers from NCO prepolymers based on 2,4-MDI, a process for their preparation and their use |
| PCT/EP2007/000446 WO2007087987A1 (en) | 2006-02-01 | 2007-01-19 | Polyurethane cast elastomers formed from nco prepolymers based on 2,4'-mdi, a process for their preparation and their use |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2640685A1 true CA2640685A1 (en) | 2007-08-09 |
Family
ID=37808065
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002640685A Abandoned CA2640685A1 (en) | 2006-02-01 | 2007-01-19 | Polyurethane cast elastomers formed from nco prepolymers based on 2,4'-mdi, a process for their preparation and their use |
Country Status (11)
| Country | Link |
|---|---|
| EP (1) | EP1981923A1 (en) |
| JP (1) | JP2009525363A (en) |
| KR (1) | KR20080097416A (en) |
| CN (1) | CN101379105A (en) |
| BR (1) | BRPI0707383A2 (en) |
| CA (1) | CA2640685A1 (en) |
| DE (1) | DE102006004527A1 (en) |
| RU (1) | RU2008135000A (en) |
| TW (1) | TW200740868A (en) |
| WO (1) | WO2007087987A1 (en) |
| ZA (1) | ZA200806596B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8097675B2 (en) | 2008-03-28 | 2012-01-17 | Bayer Materialscience Ag | 2,2′-MDI-based isocyanate mixtures, polyisocyanate polyaddition products prepared therefrom, processes for making the same and methods for their use |
| US9096707B2 (en) | 2012-02-13 | 2015-08-04 | Dow Global Technologies Llc | Elastomers for paper mill equipment |
Families Citing this family (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008133343A (en) * | 2006-11-28 | 2008-06-12 | Nippon Polyurethane Ind Co Ltd | Urethane elastomer-forming composition composed of urethane prepolymer obtained by using 2,4'-mdi as principal component |
| KR100942359B1 (en) * | 2007-11-06 | 2010-02-12 | 주식회사 효성 | Method for preparing polyurethaneurea elastic fiber with improved heat settability |
| DE102008045223A1 (en) * | 2007-11-20 | 2009-05-28 | Bayer Materialscience Ag | Polyurethane / polyurea elastomers based on 2,4'-diphenylmethane diisocyanate prepolymers and their preparation |
| DE102008012971A1 (en) | 2008-03-06 | 2009-05-28 | Bayer Materialscience Ag | Preparing polyurethane prepolymer, useful to prepare polyurethane/polyurea elastomer, comprises contacting diphenylmethane diisocyanate with polyol and removing non-reacted diphenylmethane diisocyanate by distillation |
| US20130109830A1 (en) * | 2010-05-07 | 2013-05-02 | Bayer Intellectual Property Gmbh | Polyurethane elastomers, a method for producing same, and use thereof |
| EP2455410A1 (en) * | 2010-11-23 | 2012-05-23 | Bayer MaterialScience AG | Polyurethane elastomer moulded parts composed of diphenylmethane diisocyanate based NCO prepolymers and metal salt complexes and method for producing same |
| CN102181033A (en) * | 2011-03-28 | 2011-09-14 | 来安县安泰聚氨酯制品有限公司 | Technology formula of polyurethane stripping wheel |
| EP2559716A1 (en) | 2011-08-15 | 2013-02-20 | Basf Se | Polyurethane cast resin |
| CN103923457B (en) * | 2014-03-27 | 2016-08-17 | 黎明化工研究设计院有限责任公司 | A kind of High-abrasion-resistpolyurethane polyurethane elastomer and preparation method thereof |
| CN106164709B (en) * | 2014-03-28 | 2019-12-20 | 豪雅镜片泰国有限公司 | Polyisocyanate monomer composition for optical member, and method for producing same |
| JP6110827B2 (en) * | 2014-09-29 | 2017-04-05 | 富士フイルム株式会社 | Endoscope flexible tube, endoscope adhesive, endoscope medical device, and endoscope flexible tube and endoscope medical device manufacturing method |
| CN109503804A (en) * | 2018-12-10 | 2019-03-22 | 山西省化工研究所（有限公司） | A kind of room temperature curing high-performance polyurethane elastomer composition |
| US20220411577A1 (en) * | 2019-10-09 | 2022-12-29 | Dupont Polymers, Inc. | Improved polyester |
| US20210122007A1 (en) * | 2019-10-23 | 2021-04-29 | Skc Co., Ltd. | Composition for polishing pad and polishing pad |
| EP3835335A1 (en) | 2019-12-12 | 2021-06-16 | Covestro Deutschland AG | Method for producing wood-based panels |
| CN115122453A (en) | 2021-03-24 | 2022-09-30 | 科思创德国股份有限公司 | Method for preparing artificial board |
| EP4223826A1 (en) | 2022-02-08 | 2023-08-09 | Covestro Deutschland AG | Isocyanate composition and use thereof |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2928182A1 (en) * | 1979-07-12 | 1981-01-29 | Bayer Ag | METHOD FOR PRODUCING ELASTIC, CELL-SHAPED, POLYURETHANE UREAS, IF ANY |
| DE3716479A1 (en) * | 1987-05-16 | 1988-11-24 | Elastogran Gmbh | METHOD FOR PRODUCING COATINGS FROM POLYURETHANE SINGLE-COMPONENT SYSTEMS AND WATER VAPOR |
| JP3810320B2 (en) * | 1999-11-30 | 2006-08-16 | ケムチュア コーポレイション | High performance polyurethane elastomers from MDI prepolymers with reduced free MDI monomer content |
| TW589421B (en) * | 2000-04-26 | 2004-06-01 | Du Pont | Spandex with high heat-set efficiency |
| DE10216659A1 (en) * | 2002-04-15 | 2003-10-23 | Basf Ag | A process for preparation of isocyanate compositions with blocked isocyanate groups useful in the preparation of paints, coatings, adhesives, and for elastification of epoxide and phenol resins |
| DE102004022683A1 (en) * | 2004-05-05 | 2005-11-24 | Basf Ag | Production of polyurea spray elastomer for use in concrete repair and waterproofing, involves reacting a prepolymer derived largely from 2,4-diphenyl-methanedi-isocyanate with an amine component |
-
2006
- 2006-02-01 DE DE102006004527A patent/DE102006004527A1/en not_active Withdrawn
-
2007
- 2007-01-19 WO PCT/EP2007/000446 patent/WO2007087987A1/en active Application Filing
- 2007-01-19 KR KR1020087018910A patent/KR20080097416A/en not_active Application Discontinuation
- 2007-01-19 EP EP07702879A patent/EP1981923A1/en not_active Withdrawn
- 2007-01-19 BR BRPI0707383-6A patent/BRPI0707383A2/en not_active IP Right Cessation
- 2007-01-19 CA CA002640685A patent/CA2640685A1/en not_active Abandoned
- 2007-01-19 JP JP2008552712A patent/JP2009525363A/en not_active Withdrawn
- 2007-01-19 RU RU2008135000/04A patent/RU2008135000A/en not_active Application Discontinuation
- 2007-01-19 CN CNA200780004051XA patent/CN101379105A/en active Pending
- 2007-01-31 TW TW096103448A patent/TW200740868A/en unknown
-
2008
- 2008-07-29 ZA ZA200806596A patent/ZA200806596B/en unknown
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8097675B2 (en) | 2008-03-28 | 2012-01-17 | Bayer Materialscience Ag | 2,2′-MDI-based isocyanate mixtures, polyisocyanate polyaddition products prepared therefrom, processes for making the same and methods for their use |
| US9096707B2 (en) | 2012-02-13 | 2015-08-04 | Dow Global Technologies Llc | Elastomers for paper mill equipment |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2007087987A1 (en) | 2007-08-09 |
| ZA200806596B (en) | 2009-10-28 |
| BRPI0707383A2 (en) | 2011-05-03 |
| KR20080097416A (en) | 2008-11-05 |
| RU2008135000A (en) | 2010-03-10 |
| CN101379105A (en) | 2009-03-04 |
| JP2009525363A (en) | 2009-07-09 |
| DE102006004527A1 (en) | 2007-08-09 |
| EP1981923A1 (en) | 2008-10-22 |
| TW200740868A (en) | 2007-11-01 |
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| Date | Code | Title | Description |
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| FZDE | Discontinued |
Effective date: 20130121 |