GB2227749A - Production of polyurethanes and polyurethane-ureas - Google Patents

Production of polyurethanes and polyurethane-ureas Download PDF

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Publication number
GB2227749A
GB2227749A GB8929220A GB8929220A GB2227749A GB 2227749 A GB2227749 A GB 2227749A GB 8929220 A GB8929220 A GB 8929220A GB 8929220 A GB8929220 A GB 8929220A GB 2227749 A GB2227749 A GB 2227749A
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GB
United Kingdom
Prior art keywords
polyurethane
polyol
urea
chain extender
compound
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB8929220A
Other versions
GB8929220D0 (en
Inventor
The University Of M Technology
Nippon Paint Co Ltd
John Lawrence Stanford
Richard Heywood Still
Arthur N Wilkinson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
University of Manchester Institute of Science and Technology (UMIST)
University of Manchester
Nippon Paint Co Ltd
Original Assignee
University of Manchester Institute of Science and Technology (UMIST)
University of Manchester
Nippon Paint Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by University of Manchester Institute of Science and Technology (UMIST), University of Manchester, Nippon Paint Co Ltd filed Critical University of Manchester Institute of Science and Technology (UMIST)
Publication of GB8929220D0 publication Critical patent/GB8929220D0/en
Publication of GB2227749A publication Critical patent/GB2227749A/en
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • 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
    • 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
    • C08G18/48—Polyethers
    • C08G18/4833—Polyethers containing oxyethylene units
    • C08G18/4837—Polyethers containing oxyethylene units and other oxyalkylene units
    • C08G18/4841—Polyethers containing oxyethylene units and other oxyalkylene units containing oxyethylene end groups
    • 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
    • C08G18/65—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen
    • C08G18/66—Compounds of groups C08G18/42, C08G18/48, or C08G18/52
    • C08G18/6666—Compounds of group C08G18/48 or C08G18/52
    • C08G18/667—Compounds of group C08G18/48 or C08G18/52 with compounds of group C08G18/32 or polyamines of C08G18/38
    • 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
    • C08G2120/00—Compositions for reaction injection moulding processes

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Polyurethanes Or Polyureas (AREA)

Abstract

Polyurethanes and polyurethane-ureas are prepared by reacting a polyol having a functionality of at least 3.1 provided by primary hydroxyl groups and a molar mass of at least 1000 per hydroxyl group, a polyfunctional isocyanate compound, and a chain extender which is either a polyfunctional hydroxy compound (for the production of a polyurethane) or a polyfunctional amino compound (for the production of a polyurethane-urea). The chain extender provides a hard segment content of 30 to 80% in the polyurethane or polyurethane-urea. A Reaction Injection Moulding technique is preferably used.

Description

PRODUCTION OF POLYURETHANES AND POLYURETHANE-UREAS The present invention relates to the formation of polyurethanes and polyurethane-ureas, and particularly but not exclusively to their formation in Reaction Injection Moulding (RIM) techniques.
RIM is a well established technique in which two reactant streams (which together react to form the desired polymer) impinge upon each other and the mixture is then injected into a mould where reaction takes place to produce the moulded article. For the production of polyurethanes, one reactant stream comprises a polyfunctional isocyanate and the other stream comprises a polyfunctional hydroxy compound.
In the case of poiyurethane-ureas, one stream again comprises a polyfunctional isocyanate compound and the other comprises a polyfunctional hydroxy compound and a polyfunctional amino compound.
For polyurethanes, it is known that the polyfunctional hydroxy compound may be a polyether triol although as well understood in this art such compounds have a functionality of less than 3. It is also known that such triols may be used in conjunction with a chain extenoer diol (usually ethylene glycol) which provides a hard segment content for the polyurethane. For pclyurethane-ureas it is also known to use a polyether triol together with a diamine (which provides a hard segment content for the polyurethane-urea).
There is however a disadvantage with such triol based polyurethanes and polyurethane-ureas in that they require comparatively long residence times in the (heated N, mould to acquire sufficient green strength prior to further processing, eg. post-curing.
Obviously whilst the mould is occupied by the article if cannot be used for any further moulding operation and this represent a disadvantage so far as production of the articles is concerned.
Furthermore the tensile strength, tear strength, ultimate elongation and tensile toughness of the triol based polyurethanes and polyurethane-ureas are not always adequate for many applications.
It is therefore an object of the present invention to obviate or mitigate the abovementioned disadvantages.
According to the present invention there is provided a method of forming a polyurethane or polyurethane-urea comprising reacting a polyol having a functionality of at least 3.1 provided by primary hydroxyl groups, and a molar mass of at least 1000 per hydroxyl group with a polyfunctional isocyanate compound and with a chain extender which is either a polyfunctional hydroxy compound or a polyfunctional amino compound and which provides a hard segment content for the polyurethane or the polyurethane-urea, the amount of said chain extender being such as to give a hard segment content of 30 to 80% in the polyurethane or polyurethane-urea.
The invention has been based on the discovery that comparatively high molecular weight polyols containing primary hydroxyl groups and having a functionality of at least 3.1 (preferably 3.5 to 8) may be used to produce polyurethanes and polyurethaneureas which have improved tensile properties as compared to the triol based products and which when produced by RIM techniques) acquire comparatively quickly sufficient green strength to be removed from the mould. Preferably the polyol has a molar mass of at least 1250, more preferably at least 1500, and most preferably at least 2000 per hydroxyl group.
Preferably also the polyol is one produced by oxyalkylation of a ow mci ecular weight polyhydroxy initiator C in further reaction. (if necessary) of the oxyaikyl teo product to produce the required primary hydroxyl groups.
The preferred polyols are oxypropylated products in which the required primary hydroxyl groups have been prepared by reaction of the oxypropylated product with ethylene oxide or a lactone (eg. - caprolactone).
Most preferably the polyols are oxypropylated tetrols, ie. have a functionality of 3.1 to 4 and their molecular weight distributions are less than 1.8.
Such tetrols may be produced from pentaerythritol as the polyhydroxy initiator compound.
The Hard Segment content (HS) is defined as: mass of chain + mass of stoichiometric HS = extender equivalent of isocyanate x 100% total mass where total mass represents the total mass of the polyol, the chain extender and the isocyanate.
The higher the Hard Segment content the better are the tensile properties cf the polyurethane or polyurethane-urea. Preferably the hard segment content is at least 50%. Preferably also at least 0.02 mole of chain extender is used per 100 parts by weight of the polyol.
The chain extenders used for the reaction preferably have a molecular weight upto about 400.
For the production of polyurethanes, the preferred chain extenders are diols, particularly ethylene glycol. For the production of polyurethane-ureas the preferred chain extenders are diamines, preferably aromatic diamines, most preferably sterically hindered aromatic diamines. A particularly suitable diamine is diethyltoluene diamine.
Polyfunctional isocyanates as conventionally used for production of polyurethanes and polyurethane-ureas may be used in the method in the invention. Such isocyanates are preferably socyanate prepolymers preferably having about 2.0 to 2.5 -NCO groups per molecule, an NCO equivalent value of about 80 to 500, and containing at least 80% by mole of diisocyanate.
A preferred example is liquefied MDI.
Preferably also the stoichiometry of the reaction is such that the ratio of NCO groups to a- total of hydroxyl groups and amino groups (if a polyurethaneurea is being prepared) is 1 to 1.2, more preferably 1.01 to 1.10, eg. 1.03.
The polyurethanes and polyurethane-ureas may be produced by standard RIM techniques using conventional catalysts.
The invention will be described by way of example only, with reference to the following Examples in which all parts are by weight unless otherwise indicated, and also with reference to the accompanying drawings which illustrate results obtained in Example 2 and Comparative Example 2.
EXAMPLE 1 A copolyurethane was produced by Reaction Injection Moulding from polyol and isocyanate streams as described below.
The polyol stream (the 'resin' stream) comprised 100 parts of an ethylene oxide tipped polyether tetrol of nominally 8000g moll and 25.25 parts of ethylene glycol. This resin stream additionally comprised 0.7 parts of triethyldiamine (Dabco 33 LV ex Air Products) and 0.1 parts a dibutyltinlaurate (Dabco T12 ex Air Products). These latter two compounds function as catalysts for the formulation of the polyurethane.
The isocyanate stream comprised 146 parts of Isonate M340 (ex Dow Chemicals), a liquefied MDI having an equivalent weight of 160g mol The polyurethane was produced on a standard RIM apparatus provided I th a 300mm x 300rz. x 4rnm plaque mould preheated to 7 & C using a pressurised water heater under typical RIM processing conditions as set out in Table 1.
TABLE 1
I socyanate Resin Stream Stream Stream throughput (gs-1) 124 143.6 Stream pressure (psi) 3000 3000 Stream temperature ( C) 400 35 TABLE 2
Critical Strain Energy Release Rase (kJm-2) Example 1 6.8 Comp. Example i | 2.2 TABLE 3
Modulus Tensile Ultimate Strength Elongation E(MPa) | #u* (MPa) | #u* (%) Example 1 209 19.4 135 comp.
Example 1 290 22 169 These results show that the use of a high molar mass tetrol (Example 1) in place of a triol (Comp.
Example 1) gives a polyurethane of much improved tear strength.
EXAMPLE 2 A copolyurethane-urea was produced by Reaction Injection Moulding as follows.
The polyol (or 'resin') stream comprised 100 parts of a nominally 8000g molar polyether tetrol with primary hydroxyl groups, 37.48 parts of diethyl toluene diamine (DETDA-ex Lonza Chemicals AG (idealised structure shown below) and 0.31 parts of dibutyltindilaurate (Dabco T12 ex Air Products)).
The isocyanate stream comprised 77.1 parts of Isonate M340 (ex Dow Chemicals), liquefied MDI of 160g mol-1 equivalent weight. The material was moulded using the streak pressures and stream temperature shown in Table 1 above. The polyurethane-rea obtained had a naro segment content of 508. The mould used was such as te produce strips of dimensions 5 x 250 x 4mm. The moulding operation was repeated for various mould temperatures and demould times On completion of the curing (ie. demould) time at a set temperature the strips were removed from the mould and subjected to a 93 bend over the mould.Strips which showed no damage were classified as 'very tough' other strips were variously classed as very brittle, brittle and tough.
The results are shown In Fig. 1 (discussed below) which is a moulding area diagram of mould temperature ( C) vs demould @ms (seconds). The shaded area is the so called demoulding windox for producing very tough materials.
Tensile stress-strain properties of the products obtained at a mould temperature of 700 and a demould time of 30s are listed in Table 4.
COMPARATIVE EXAMPLE 2 Example 2 was repeated except that the tetrol was replaced by a nominally 6000g mol-1 polyether triol (M111 ex Lankro Chemicais) and the amounts of DETDA and isonate were respectively 37.85 parts and 78.95 parts.
The moulding area diagram obtained is shown in Fig. 2 and the tensile stress-strain properties are included in Table 4 below.
TABLE 4
Tensile Ultimate Tensile Strength Elongation Toughness Modulus #u* (MPA) #u* (%) Ut (MJ m-3) E(MPa) Examp. 296 24 197 45 Two Comp.
Examp.
Two 307 14 170 24 It can be seen from a comparison of Figs. 1 and 2 that copolyurethane-ureas moulded with a high molar mass tetrol (xample 23 n lace of the trick (Comp.
Example 2) exhibit much improved demoulding characteristics as evidenced by the much greater area of the demoulding window in F1 1 as compared to Fig.
2.
Furthermore, the results in Table 3 show that tetrol based copolyurethane-urea (Example 2) exhibits superior tensile strength, ultimate elongation and ultimate tensile toughness as compared to the triol based product (Comp. Example 2) whilst retaining an equivalent modulus.

Claims (26)

1. A method of forming a polyurethane or polyurethane-urea comprising reacting a polyol having a functionality of at least 3.1 provided by primary hydroxyl groups and a molar mass of at least 1000 per hydroxyl group with a polyfunctional isocyanate compound and with a chain extender which is either a polyfunctional hydroxy compound or a polyfunctional amino compound and which provides a hard segment content for the polyurethane or polyurethane-urea, the amount of said chain extender being such as to give a hard segment content of 30 tc 80% in the polyurethane or polyurethane-urea.
2. A method as claimed in Claim 1 which is effected by Reaction Injection Moulding technIque.
3. A method as claimed in Claim 1 or 2 wherein the polyol has functionality of 3.5 to 8.
4. A method as claimed in any one of Claims 1 to 3 wherein the polyol has e molar mass cf at least 1250 per hydroxy- crour.
5. A method as claimed in Claim 4 wherein the polyol has a molar mass ci at least 1500 per hydroxyl group.
6. A method as claimed in Claim 5 wherein the polyol has a molar mass ci at east 2000 per hydroxyl group.
7. A method as claimed In in any one of Claims 1 to 6 wherein n the polyol 5 one produced by oxyalkylation of a low molecular weight polyhydroxy initiator compound and fu--hz eartion (if necessary) of the oxyalkylated product to produce the required primary hydroxyl groups.
8. A method as claimed in Claim 7 wherein the polyol if a primary hydroxide tipped oxypropylated derivative of the initiator compound.
9. A method as claimed in Claim 8 wherein the polyol is a primary hydroxide tipped oxypropylated tetrol having a functionality of 3.1 to 4.
10. A method as claimed in Claim 9 wherein the polyol is a primary hydroxide tipped oxypropylated pentaerythritol.
11. A method as claimed in any one of Claims 1 to 10 wherein the polyol has a molecular weight distribution of less than 1.8.
12. A method as claimed in any one of Claims 1 to 11 wherein the resultant polyurethane or polyurethane-urea has a hard segment content of 50 to 80%.
13. A method as claimed in any one of Claims 1 to 12 wherein at least C.C2 moles of the chain extender are used per 100 parts by weight of the polyol.
14. A method as claimed in any one of Claims 1 to 13 wherein the chain extender has a molecular weight upto about 400.
15. A method as claimed in any one of Claims 1 to 14 for the production of a olyurethane wherein the chain extender is a diol.
16. A method as claimed in Claim 15 wherein the chain extender is ethylene gl=oi.
17. A method as claimed in any one of Claims 1 to 14 for the production of a polyurethane-urea wherein the chain extender is a diamine.
18. A method as claimed in Claim 17 wherein the diamine is an aromatic diamine.
19. A method as claimed in Claim 18 wherein the aromatic diamine is a sterically hindered aromatic diamine.
20. A method as claimed in Claim 19 wherein the diamine is diethyltoluene d~a,..ine.
21. A method as claire in any one of Claims 1 to 30 wherein the polyfunctional isocyanate is an isocyanate prepolymer.
22. A method as claimed in Claim 21 wherein the isocyanate prepolymer has about 2.0 to 2.5 -NCO groups per molecule, an NCO equivalent value of about 80 to 500, and contains at least 80% by mole of diisocyanate.
23. A method as claimed in any one of Claims 1 to 22 wherein the polyfunctional isocyanate is liquefied MDI.
24. A method as claimed in any one of Claims 1 to 23 wherein the stoichiometry of the reaction is such that the ratio of NCO groups to the total of hydroxyl groups and amino groups (if a polyurethaneurea is being prepared) is 1 to 1.2.
25. A method as claimed in Claim 24 wherein said stoichiometry is 1.01 to 1.10.
26. A method of producing a polyurethane or polyurethane-urea moulded article by a Reaction Injection Moulding technique wherein reactant streams impinge on each other and this resultant is passed into a mould for the article wherein the reactants stream together comprise a polyol having functionality of at least 3.1 provided by primary hydroxyl groups and a molar mass of at least 1000 per hydroxyl group, a polyfunctiona isocyanate compound, and a chain extender which is either a polyfunctional hydroxy compound or a polyfunctiona anino compound and which a hard segment content for the polyurethane or polyurethane-urea, the amount of said chain extender being such as to give a hard segment content of 30 to 80% in the polyurethane cr polyurethane-urea.
GB8929220A 1988-12-31 1989-12-27 Production of polyurethanes and polyurethane-ureas Withdrawn GB2227749A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB898900041A GB8900041D0 (en) 1988-12-31 1988-12-31 Production of polyurethanes and polyurethane-ureas

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GB2227749A true GB2227749A (en) 1990-08-08

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GB8929220A Withdrawn GB2227749A (en) 1988-12-31 1989-12-27 Production of polyurethanes and polyurethane-ureas

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1264185A (en) * 1968-10-01 1972-02-16
US4289856A (en) * 1978-11-14 1981-09-15 The Toyo Rubber Industry Co., Ltd. Process for preparing non-yellowing integral-skinned polyurethane foam using a polyol having a functionality of 4 to 8
GB2082609A (en) * 1980-08-27 1982-03-10 Upjohn Co Amine modified polyurethane elastomers
EP0093861A1 (en) * 1982-04-23 1983-11-16 Texaco Development Corporation A reaction injection molded elastomer containing an internal mold release made by a two-stream system
GB2181736A (en) * 1985-10-22 1987-04-29 Basf Corp Reaction injection molded microcellular polyurethane elastomers
EP0283216A2 (en) * 1987-03-11 1988-09-21 Imperial Chemical Industries Plc Improved prepolymer compositions for polyurea reaction injection molding

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1264185A (en) * 1968-10-01 1972-02-16
US4289856A (en) * 1978-11-14 1981-09-15 The Toyo Rubber Industry Co., Ltd. Process for preparing non-yellowing integral-skinned polyurethane foam using a polyol having a functionality of 4 to 8
US4289856B1 (en) * 1978-11-14 1984-10-02
GB2082609A (en) * 1980-08-27 1982-03-10 Upjohn Co Amine modified polyurethane elastomers
EP0093861A1 (en) * 1982-04-23 1983-11-16 Texaco Development Corporation A reaction injection molded elastomer containing an internal mold release made by a two-stream system
GB2181736A (en) * 1985-10-22 1987-04-29 Basf Corp Reaction injection molded microcellular polyurethane elastomers
EP0283216A2 (en) * 1987-03-11 1988-09-21 Imperial Chemical Industries Plc Improved prepolymer compositions for polyurea reaction injection molding

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Publication number Publication date
GB8929220D0 (en) 1990-02-28
GB8900041D0 (en) 1989-03-01

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