CA1063748A - Molding grade polyurethane - Google Patents
Molding grade polyurethaneInfo
- Publication number
- CA1063748A CA1063748A CA225,911A CA225911A CA1063748A CA 1063748 A CA1063748 A CA 1063748A CA 225911 A CA225911 A CA 225911A CA 1063748 A CA1063748 A CA 1063748A
- Authority
- CA
- Canada
- Prior art keywords
- diol
- polyol
- prepolymer
- reacted
- ether
- 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.)
- Expired
Links
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
- C08G18/28—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
- C08G18/63—Block or graft polymers obtained by polymerising compounds having carbon-to-carbon double bonds on to polymers
- C08G18/632—Block or graft polymers obtained by polymerising compounds having carbon-to-carbon double bonds on to polymers onto polyethers
-
- 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
Abstract
ABSTRACT OF DISCLOSURE
A relatively inexpensive injection molding-grade thermo-plastic polyurethane elastomer is based on a modified polyether diol--a modified polypropylene glycol (PPG) ether. This elastomer has improved toughness, abrasion resistance and general good mechanical properties. Its temperature insensitivity and low temperature flexibility are exceptional. It is flexible to impact at -50°F and stiff enough at 250°F to allow painting without dis-tortion. Of special interest is the fact that this polymer is injection moldable and possesses properties adequate for exterior automobile trim components and the like.
The polyether polyol is a poly (oxyalkylene) diol reacted with a 50/50 styrene/acrylonitrile monomer mixture in the presence of a free radical catalyst. While a one shot method of preparation can be used, the capped polyol is preferably reacted with an aromatic diisocyanate to form a prepolymer in a known manner. The prepolymer is thereafter reacted with a C2 to C6 alkane diol, pan cast, cured and aged, followed by grinding to give the molding composition.
It is preferred to blend the polyol with a minor amount of a poly alkane ether diol prior to forming the prepolymer as this enhances the moldability and properties of the thermoplastic polyurethane.
A relatively inexpensive injection molding-grade thermo-plastic polyurethane elastomer is based on a modified polyether diol--a modified polypropylene glycol (PPG) ether. This elastomer has improved toughness, abrasion resistance and general good mechanical properties. Its temperature insensitivity and low temperature flexibility are exceptional. It is flexible to impact at -50°F and stiff enough at 250°F to allow painting without dis-tortion. Of special interest is the fact that this polymer is injection moldable and possesses properties adequate for exterior automobile trim components and the like.
The polyether polyol is a poly (oxyalkylene) diol reacted with a 50/50 styrene/acrylonitrile monomer mixture in the presence of a free radical catalyst. While a one shot method of preparation can be used, the capped polyol is preferably reacted with an aromatic diisocyanate to form a prepolymer in a known manner. The prepolymer is thereafter reacted with a C2 to C6 alkane diol, pan cast, cured and aged, followed by grinding to give the molding composition.
It is preferred to blend the polyol with a minor amount of a poly alkane ether diol prior to forming the prepolymer as this enhances the moldability and properties of the thermoplastic polyurethane.
Description
1~3~
Thermoplastic polyurethanes llave been prepared from polyether and polyester polyols. The polyester polymers are relatively e~pensive and have good to excellent physical properties overall but such polymers have generally poor humidity resistance and low tempe~ature properties.
Injection moldable polyether-based polymers have been based on the PTMEG
polyols which are expensive. Conventional PPG ether based poly~ers are not amendable to injection molding and have physical properties unacceptable for use in demanding application such as automobile exterior trim parts.
It has been found that a polyether diol-based urethane elastomer of injection molding quality and with good to excellent overall physical properties can be prepared from a polyether diol which has been reacted with a 50/50 styrene/acrylonitrile monomer misture by a free radical polymeri-zation. See U.S. Patent Nos. 3,304,273; 3,383,351 and 3,418,354; and Belgian Patent No. 788,115. ~
According to the present invention, there is provided an in- ~ -jection molding-grade thermoplastic polyurethane having good low temperature ~ -properties made by reacting the following:
Parts by weight Grafted polyol 100 poly alkane ether diol 2 to 70 Aromatic polyisocyanate 40 to 100 - C2-C6 alkane diol 10 to 40 ~
wherein said grafted polyol is a 2000 to 5000 molecular weight copolymer --of 70 to 90 weight percent of a 1000 to 4000 molecular weight poly ~oxy Cl-C4 alkene)diol, reacted by a free radical polymerization with 10 to 30 weight percent of a monomer mixture of 1 part by weight of a vinylaromatic and 0.1 to 9 parts of an olefinic C2-C6 nitrile, and said polyalkylane ether diol has a molecular weight in the range of 500 to 2500.
This modified polyether polyol is preferably reacted in the usual manner with an aromatic di socyanate to prepare a prepolymer having a free NCO content in the range of 7 to 15%.
The modified polyether polyol is admixed with a minor amount of a poly alkane ether diol.
~ .,:; '.
B
l......... .. ... .
.. ., , . .. .. . ~ .. " .. ~, -- `. .. ` . . ... .
~^ L~ '7~1~
The prepolylner is thareafter reacted with a short chain alkane diol and cast in slab form or extruded ancL pelletized. After curing and aging for a few days the resulting elastomer is ground to prepare the molding composition. Materials such as colorants and stabilizers may be blended into the ground elastomer to give a complete molding composition.
The molding composition can be molded in any conventional manner such as injection molding to 400 to 500F in a plunger-type machine.
The molded product is generally a tough and abrasion resistant and, somewhat surprisingly, has superior ' :' i .
- la -1 ~
~ 7 humidity and aging resistance, and exceptional low temperature flexibility.
For example, an elastomer o~ this invention having a flex modulus (ASTMD-790) of 15000 psi will consistently pass a -20F painted Dart Impact (FBMS-2-23) and cold flex tes-t (FBTM- ~ -58-5).
The following table gives the ingredients and the pre- -ferred proportions that can be used to prepare the present polyurethane:
Modified polyol, PBW* (with ether diol, i~ used) 100 Aromatic diisocyanate, to FNC0 of: 4 to 15 C2-C6 alkane diol, PBW 5 to 30 *parts by weight The modified polyol is a 2000 to 5000 molecular weight `~
reaction product of:
a) 70 to 90 weight percent of a 1000 to ~000~ pre~erably 2400 to 3200, molecular weight poly (oxy Cl-C4 alkene) diol, reacted by a ~ree radical polymerization with b) 10 to 30 weight percent of a monomer mixture of 1 part by weight of a vinylaromatic and, 0.1 to 9, pre~erably 0~3 s to 3 parts~ of an olefinic C2-G6 nitrile. ~;
The poly (oxy Cl-C4 alkene) diol is preferably the reaction product of propylene glycol with first propylene oxide and then ethylene oxide the ratio of the two oxides being 3-5 parts o~ the propylene to one o~ the ethylene.
The polyalkane ether diol has a molecular weight in the ranga of 500 to 2500, preferably 650 to 1500. While quantities as low as 2 parts by weight will have an observable and desirable effect on the final polymer and quantities as high as 70 parts by weight will produce a useful thermop~astLc polymer, for demanding automotive appIications the physical properties given by 5-50 parts by weight of the poly alkene ether diol are preferred.
The aromatic polyisocyanate is any of the co~nercially used ones and is preferably selected from the group consisting of 4, 4' -diphenylmethane diisocyanate (~I); tolylene diisocyanate (TDI); 1, 5 naphthalene diisocyanate; dianisidine diisocyanate (DADI); 3, 3' -demethyl 4~ 4' -bipheneyl diisocyanate (XDI).
The straight-chain C2 C6 alkane diol is preferably end-terminated with the hydroxy groups.
The prepolymer process is quite straightforward but if the following procedure is not ~ollowed with reasonable care a thermoset and sometimes microcellular elastomer may result. The index of the mixture, the reaction temperatures, and water con-tents of the ingredients should be closely controlled, as is known.
The polyol is degassed and heated, for example, to 235F
and the aromatic diisocyanate is added with the mixture being al-lowed to exotherm, for example, to 250F. It is then degassed and the free NC0 content obtained. Preferably the free NC0 is in the range o~ 8 to 12. In the example it was 8.35. The prepolymer can be stored in readiness for the next step.
The short chain diol such as 1, )~ -butanediol (BD0), is separately prepared, and dried if necessary, and mixed with the wax release agent, if a wax is to be used. The diol mixture and the prepolymer are preferably brought together in a casting ma-chine in a continuous manner at about 230F. A~ter thorough mixing o~ the two ingredients, the mixture is cast out in a casting pan, which is preferably maintained at a temperature above 210F.
The cast layer can for example be 1" thick and a~ter being allowed to set 4 or 5 minutes, can be cut into 3'1 x 3u chunks~ removed and placed in containers. A~ter aging ~or a week or so the elastomer can be ground to the size desired for molding and mixed with whatever additional materîals may be desired. Alternatively, the mixture of diol and prepolymer can be extruded and pelletized to .
r-513/51 give a moldable compositlon.
It has also been ~ound that by the addition of catalyst to the mlxture~ the reactiorls can be speeded up so that poly-urethane can be directly cast into a~ mold to product a molded product. The catalyst used can be o-f` the dibutyl-tin~dilaurate, mercaptide or other known tyoe and the casting temperature can be substantially lower~ say 105F, with the mold being at 1~0 180F.
The following gives an example o~ the invention:
EXAMPLE
Equivalent PBW
Modified polyol 1.0 100 ~DI 5 35.68 ~ -BD0 L~.02 12.&9 Wax, phr. 0.2 Specific Gravity 1.15 -Hardness, Shore D (5 secs) 25 Tensile Strength (orig.) 1169 -after 70 hrs. 212F (+2.6%)1199 - after 7 da/175F/100%RH (~1.5%)1187 Elongation (orig.) 253 - after 70 hrs./212F (-28.8~)180%
after 7 da/175F~100~ORH (-26.1~)187 Tear Stréngth (Die C) 210 Stiffness @72F 0.5 in lbs. (orig.) 58~9 @-20F 3.0 in lbs. 9855 after 70 hrs/212F 0.5 in/lbs. (~14.3%)6650 !.' ' 160F 0.25 in lbs. 4839 Tensile set @200% elongation 61.0~o 30 Dart impact-flex @-20F (Fisher Body Test) as received (no fracture) Penetrate no shatter after 70 hrs/212F (no fracture) Pass Stretch test @250F (4~ max.) No change . ,., .. , . ~ . , - - , - . . . .
r-513/518 The in-teresting point made by the above table is that while the -20F stiffness value of 9855 psi is outstanding there is not an unacceptable loss in physical properties at the higher temperat~res. For example, the 1~0F stiffness value is 4839 psi.
DRAWING
The drawing attached to and forming a part o~ -this invention is a schematic illustration of the process of this invention. The elastomer can be prepared by the one shot or prepolymer procedure, the latter being illustrated.
The drawing also illustrates the use of a poly alkane ether diol, PTMEG (polytetramethylene ether glycol)~ a pre~erred embodiment o~ the invention. In this embodiment, the follcwing proportions are used:
Parts by Weight ~odi~ied polyol 100 Poly alkane ether diol 5-50 Aromatic diisocyanate 40 to 100 C2-C6 alkane diol 10 to 40 ': .
~.. . ~ , . . .. .. .
.. : . , -. . ; -~3 ~-513/518 The thermoplastic urethane o~ the prePerred embodiment have -the following properties:
Test Method `
Specific Gravity 1 14t-0.02 ASTMD-792 Tensile Strength, psi 2500 ~mi.nimum) AST~-412 Elongation, ~ 400 (minimurn) ASTMD-412 Tear Strength~ pi 400 (minimum) ASTMD-624 -~
Hardness3 Shore D~ 5 secO 41+ 3 ASTMD-2240 Modulus of Elasticity, psi . -(Flexual Modulus) 11,000 (minimum) AS~MD-790 Tensile, set, % (at 200~ ;
Elongation) 70 (maximum) ASTM~-412 1/2" Mandrel Bend, -20F, .
Painted TM-58-5 ;
Durethane 100* Pass Durethane 200* Pass *Trademarks o~ PPG Industries, One Gatewa~ Center~ Pittsburgh, Pennsylvania 15222. :
Aged Properties .- -. :
Heat Aging: 70 hrs/212F, -.
; % change ..
Tensile strength -15(maximum) ASTMD-412 ,; : ,.
Elongation -20(maximum) ASTMD-412 .
Dart I~pact Pass FBMS 2-23 .~
Humidity aging: 7 days/ :
175F/100% R H , `
% change Tensile strength -15 (maximum) ASTMD-412 ~:
Elongati.on -15 (maximum ASTMD-~12 The prepolymer process is quite straightforward but if the ~ollowing procedure is not ~ollowed with reasonable care a thermoset and sometimes microcellular elastomer may result. The ' : .. : ~ , . , . . .: , . , , -. :-::.-, , , : - -- .. .
~ -513/51~
index of the mixture, the re~ction temperatures, and water contents of the in$redients should be closely con-trolled, as i9 known.
With reference to the drawing, the two polyols, the modified polyol via line ll and the poly alkene ether diol via line 13, are brought together in a reactor lO degassed and heated, for example, to 235F.
The aromatic diisocyanate is then added to the reactor via line 12 and the mixture is allowed to exotherm, for example, to 250F. It is then degassed and the free NC0 content obtained.
Preferably the free NC0 is in the range of 4 to 15, more preferably 8 to 12. In the following examples, A & B, it was 11.27 and 9.55 respectively. The prepolymer can then be stored in readiness ~or the next step.
The short chain diol such as 1,4 -butanediol (BD0)~ is separately prepared, and dried if necessary, and mixed with the wax release agent, if wax is to be used. The diol mixture and the prepolymer~ by lines 15 and 14, respectively, are brou~ht together in a casting machine 20 in a continuous manner at about 230F.
After thorough mixing of the two ingredients, the mixture is cast out via iine 16 into a casting pan, 30 which is preferably main~
tained at a temperature above 210F. The cast layer can for ex- ~ -ample be l" thick and, after being allowed to set 4 to 5 minutes, can be cut into 3" x 3" chunks, removed and placed in containers~ `
as indicated by line 17 and block 40. A~ter having been aged at 40 ~or a weeX or so the elas~omer can be ground to the size de sired for molding and mixed with whatever additional materials may be desired. Alternatively, the mixture from line 16 can be ex-truded and pelletized to give a moldable composition.
It has also been found that by the addition of catalyst to the mixture in the casting machine 20, the reactions can be speeded up so that polyurethane can be directly cast into a mold to producb a molded product. The catalysts used can be of the ~--513/51~ ~4~ ~ 7 dibutyl-tin-dilaurate, mercaptide or other known type and the casting temperature can be substantially lower~ say 105F, with the mold being at 160-180F.
The ~ollowing table gives e:xamples of the invention prepared according to the illustrated process.
: . . . : . . .......................... . - .
:., .; . ,- . . . . . .. . .. . . . .
-513/518 ~ 7 EX~IP1ES
A B
E PBW E PBW
Modified polyol 0.5 100 0;75 100 PT~EG 0.5 28.24 0.25 9.42 ~I 6.o 85.64 6.o 57.o8 BD0 5.02 26.20 5.02 17.4 Wax ~3 o.63 0.3 -55 Specific Gravity 1.15 1.14 Hardness, Shore D (5 secs) 45 40 Tensile Strength (orig.) 2995 2624 after 70 hrs/212F (-5.0%)2846 (-10.5~)2348 after 7 da/175F/lOO~RH (-11.1%) (-13~3~)2276 -Elongation ~orig.) 537% 503%
after 70 hrs/212aF (_13.8%)463% (-14.5~)430%
a~ter 7 da/175F/lOO~RH(-8.2~)493% (-4.6%)480% `~
Tear Strength (Die C) 507 416 Stiffness @72F 0.5 in lbs. (orig.)Exceeded scale limit 9855 @-20F 3.0 in lbs. 35041 20787 ;
after 70 hrs./212F 0.5 in/lbs Exceeded scale limit (~2.0%)10060 @160F 0.25 in lbs.Exceeded scale limit 5595 Tensile set @200% elongation 62.5% 53.1~o Dart impact-flex @-20F ~FB) as received (no fracture) pass pass after 70 hrs/212F (no fracture) pass pass Stretch test ~250F (4~0 max.) No change 1.6 In the table:
E=number of equivalents PBW=parts by weight FB= a Fisher Body speci~ication .
- - . -.. - . - .. - . ... . . . ... . . ....
7~
The modified polyol w~s Union Carbide Company's NIAX
D-432, a polymer of about 4000 molecular weigh~ made by reacting 80 weight percent o a 2800 molecular ueight poly (oxyalkylene) diol with 20 ~eight percent of a 50/50 (by weigh~) styren0/
acrylonitrile monomer mixture in the presence of a free radical catalyst (a~obisisobutronitrile), as described in Union Carbide's Belgian Patent N~. 788,115. The poly ~oxyalkylene) diol is made by first reacting propylene glyeol with propylene oxide and then subsequently with ethylene oxide so that the chains tarminate in ethylene oxide units. The proportions are such that there are a~out 4.88 propylene oxide units for each ethylene oxide unit.
When the poly (oxyalkylene) diol is reacted with the styrene/
.
acrylonitrile monomer mixture, it appears that some of the two monomers copolymeri~e and add to the diol and some simply - ~-copolymerize ~ithout attaching to the diol but belng intimately ~ -intermixed therewith.
The poly alkylene ether diol was a polytetramethylene ether glycolJ ~PTMEG)~ Polymeg 1000, sold by the Quaker Oats Company~ Chemical Division, Merchandise Mart Plaza, Chicago, ;
Illinois 60545. It has a molecular weight of 1000. E. I. duPont de Nemours Polyglycol 1000 can also be used.
The "MDI" was 4, 4' diph0nylmethane diisocyanate.
The "BDO" was 1, 4-butanediol.
The wax was an ethelyne-bis-steaTamide, Advawax 280F, sold by Cincinnati Milacron Chemical Inc., Reading, Ohio 45215.
Examples of automobile parts that have been made using -~
this thermpolastic urethane and tested with satisfactory results are: General Motors 1974: tl) Riviera Center Sight Shield, Part No. 9694424-439 and ~2) Oldsmobile l'B" Corner Sight Shield, Part No. 9694662-693.
* Trade Mark ~ ' ': . ;
.
Thermoplastic polyurethanes llave been prepared from polyether and polyester polyols. The polyester polymers are relatively e~pensive and have good to excellent physical properties overall but such polymers have generally poor humidity resistance and low tempe~ature properties.
Injection moldable polyether-based polymers have been based on the PTMEG
polyols which are expensive. Conventional PPG ether based poly~ers are not amendable to injection molding and have physical properties unacceptable for use in demanding application such as automobile exterior trim parts.
It has been found that a polyether diol-based urethane elastomer of injection molding quality and with good to excellent overall physical properties can be prepared from a polyether diol which has been reacted with a 50/50 styrene/acrylonitrile monomer misture by a free radical polymeri-zation. See U.S. Patent Nos. 3,304,273; 3,383,351 and 3,418,354; and Belgian Patent No. 788,115. ~
According to the present invention, there is provided an in- ~ -jection molding-grade thermoplastic polyurethane having good low temperature ~ -properties made by reacting the following:
Parts by weight Grafted polyol 100 poly alkane ether diol 2 to 70 Aromatic polyisocyanate 40 to 100 - C2-C6 alkane diol 10 to 40 ~
wherein said grafted polyol is a 2000 to 5000 molecular weight copolymer --of 70 to 90 weight percent of a 1000 to 4000 molecular weight poly ~oxy Cl-C4 alkene)diol, reacted by a free radical polymerization with 10 to 30 weight percent of a monomer mixture of 1 part by weight of a vinylaromatic and 0.1 to 9 parts of an olefinic C2-C6 nitrile, and said polyalkylane ether diol has a molecular weight in the range of 500 to 2500.
This modified polyether polyol is preferably reacted in the usual manner with an aromatic di socyanate to prepare a prepolymer having a free NCO content in the range of 7 to 15%.
The modified polyether polyol is admixed with a minor amount of a poly alkane ether diol.
~ .,:; '.
B
l......... .. ... .
.. ., , . .. .. . ~ .. " .. ~, -- `. .. ` . . ... .
~^ L~ '7~1~
The prepolylner is thareafter reacted with a short chain alkane diol and cast in slab form or extruded ancL pelletized. After curing and aging for a few days the resulting elastomer is ground to prepare the molding composition. Materials such as colorants and stabilizers may be blended into the ground elastomer to give a complete molding composition.
The molding composition can be molded in any conventional manner such as injection molding to 400 to 500F in a plunger-type machine.
The molded product is generally a tough and abrasion resistant and, somewhat surprisingly, has superior ' :' i .
- la -1 ~
~ 7 humidity and aging resistance, and exceptional low temperature flexibility.
For example, an elastomer o~ this invention having a flex modulus (ASTMD-790) of 15000 psi will consistently pass a -20F painted Dart Impact (FBMS-2-23) and cold flex tes-t (FBTM- ~ -58-5).
The following table gives the ingredients and the pre- -ferred proportions that can be used to prepare the present polyurethane:
Modified polyol, PBW* (with ether diol, i~ used) 100 Aromatic diisocyanate, to FNC0 of: 4 to 15 C2-C6 alkane diol, PBW 5 to 30 *parts by weight The modified polyol is a 2000 to 5000 molecular weight `~
reaction product of:
a) 70 to 90 weight percent of a 1000 to ~000~ pre~erably 2400 to 3200, molecular weight poly (oxy Cl-C4 alkene) diol, reacted by a ~ree radical polymerization with b) 10 to 30 weight percent of a monomer mixture of 1 part by weight of a vinylaromatic and, 0.1 to 9, pre~erably 0~3 s to 3 parts~ of an olefinic C2-G6 nitrile. ~;
The poly (oxy Cl-C4 alkene) diol is preferably the reaction product of propylene glycol with first propylene oxide and then ethylene oxide the ratio of the two oxides being 3-5 parts o~ the propylene to one o~ the ethylene.
The polyalkane ether diol has a molecular weight in the ranga of 500 to 2500, preferably 650 to 1500. While quantities as low as 2 parts by weight will have an observable and desirable effect on the final polymer and quantities as high as 70 parts by weight will produce a useful thermop~astLc polymer, for demanding automotive appIications the physical properties given by 5-50 parts by weight of the poly alkene ether diol are preferred.
The aromatic polyisocyanate is any of the co~nercially used ones and is preferably selected from the group consisting of 4, 4' -diphenylmethane diisocyanate (~I); tolylene diisocyanate (TDI); 1, 5 naphthalene diisocyanate; dianisidine diisocyanate (DADI); 3, 3' -demethyl 4~ 4' -bipheneyl diisocyanate (XDI).
The straight-chain C2 C6 alkane diol is preferably end-terminated with the hydroxy groups.
The prepolymer process is quite straightforward but if the following procedure is not ~ollowed with reasonable care a thermoset and sometimes microcellular elastomer may result. The index of the mixture, the reaction temperatures, and water con-tents of the ingredients should be closely controlled, as is known.
The polyol is degassed and heated, for example, to 235F
and the aromatic diisocyanate is added with the mixture being al-lowed to exotherm, for example, to 250F. It is then degassed and the free NC0 content obtained. Preferably the free NC0 is in the range o~ 8 to 12. In the example it was 8.35. The prepolymer can be stored in readiness for the next step.
The short chain diol such as 1, )~ -butanediol (BD0), is separately prepared, and dried if necessary, and mixed with the wax release agent, if a wax is to be used. The diol mixture and the prepolymer are preferably brought together in a casting ma-chine in a continuous manner at about 230F. A~ter thorough mixing o~ the two ingredients, the mixture is cast out in a casting pan, which is preferably maintained at a temperature above 210F.
The cast layer can for example be 1" thick and a~ter being allowed to set 4 or 5 minutes, can be cut into 3'1 x 3u chunks~ removed and placed in containers. A~ter aging ~or a week or so the elastomer can be ground to the size desired for molding and mixed with whatever additional materîals may be desired. Alternatively, the mixture of diol and prepolymer can be extruded and pelletized to .
r-513/51 give a moldable compositlon.
It has also been ~ound that by the addition of catalyst to the mlxture~ the reactiorls can be speeded up so that poly-urethane can be directly cast into a~ mold to product a molded product. The catalyst used can be o-f` the dibutyl-tin~dilaurate, mercaptide or other known tyoe and the casting temperature can be substantially lower~ say 105F, with the mold being at 1~0 180F.
The following gives an example o~ the invention:
EXAMPLE
Equivalent PBW
Modified polyol 1.0 100 ~DI 5 35.68 ~ -BD0 L~.02 12.&9 Wax, phr. 0.2 Specific Gravity 1.15 -Hardness, Shore D (5 secs) 25 Tensile Strength (orig.) 1169 -after 70 hrs. 212F (+2.6%)1199 - after 7 da/175F/100%RH (~1.5%)1187 Elongation (orig.) 253 - after 70 hrs./212F (-28.8~)180%
after 7 da/175F~100~ORH (-26.1~)187 Tear Stréngth (Die C) 210 Stiffness @72F 0.5 in lbs. (orig.) 58~9 @-20F 3.0 in lbs. 9855 after 70 hrs/212F 0.5 in/lbs. (~14.3%)6650 !.' ' 160F 0.25 in lbs. 4839 Tensile set @200% elongation 61.0~o 30 Dart impact-flex @-20F (Fisher Body Test) as received (no fracture) Penetrate no shatter after 70 hrs/212F (no fracture) Pass Stretch test @250F (4~ max.) No change . ,., .. , . ~ . , - - , - . . . .
r-513/518 The in-teresting point made by the above table is that while the -20F stiffness value of 9855 psi is outstanding there is not an unacceptable loss in physical properties at the higher temperat~res. For example, the 1~0F stiffness value is 4839 psi.
DRAWING
The drawing attached to and forming a part o~ -this invention is a schematic illustration of the process of this invention. The elastomer can be prepared by the one shot or prepolymer procedure, the latter being illustrated.
The drawing also illustrates the use of a poly alkane ether diol, PTMEG (polytetramethylene ether glycol)~ a pre~erred embodiment o~ the invention. In this embodiment, the follcwing proportions are used:
Parts by Weight ~odi~ied polyol 100 Poly alkane ether diol 5-50 Aromatic diisocyanate 40 to 100 C2-C6 alkane diol 10 to 40 ': .
~.. . ~ , . . .. .. .
.. : . , -. . ; -~3 ~-513/518 The thermoplastic urethane o~ the prePerred embodiment have -the following properties:
Test Method `
Specific Gravity 1 14t-0.02 ASTMD-792 Tensile Strength, psi 2500 ~mi.nimum) AST~-412 Elongation, ~ 400 (minimurn) ASTMD-412 Tear Strength~ pi 400 (minimum) ASTMD-624 -~
Hardness3 Shore D~ 5 secO 41+ 3 ASTMD-2240 Modulus of Elasticity, psi . -(Flexual Modulus) 11,000 (minimum) AS~MD-790 Tensile, set, % (at 200~ ;
Elongation) 70 (maximum) ASTM~-412 1/2" Mandrel Bend, -20F, .
Painted TM-58-5 ;
Durethane 100* Pass Durethane 200* Pass *Trademarks o~ PPG Industries, One Gatewa~ Center~ Pittsburgh, Pennsylvania 15222. :
Aged Properties .- -. :
Heat Aging: 70 hrs/212F, -.
; % change ..
Tensile strength -15(maximum) ASTMD-412 ,; : ,.
Elongation -20(maximum) ASTMD-412 .
Dart I~pact Pass FBMS 2-23 .~
Humidity aging: 7 days/ :
175F/100% R H , `
% change Tensile strength -15 (maximum) ASTMD-412 ~:
Elongati.on -15 (maximum ASTMD-~12 The prepolymer process is quite straightforward but if the ~ollowing procedure is not ~ollowed with reasonable care a thermoset and sometimes microcellular elastomer may result. The ' : .. : ~ , . , . . .: , . , , -. :-::.-, , , : - -- .. .
~ -513/51~
index of the mixture, the re~ction temperatures, and water contents of the in$redients should be closely con-trolled, as i9 known.
With reference to the drawing, the two polyols, the modified polyol via line ll and the poly alkene ether diol via line 13, are brought together in a reactor lO degassed and heated, for example, to 235F.
The aromatic diisocyanate is then added to the reactor via line 12 and the mixture is allowed to exotherm, for example, to 250F. It is then degassed and the free NC0 content obtained.
Preferably the free NC0 is in the range of 4 to 15, more preferably 8 to 12. In the following examples, A & B, it was 11.27 and 9.55 respectively. The prepolymer can then be stored in readiness ~or the next step.
The short chain diol such as 1,4 -butanediol (BD0)~ is separately prepared, and dried if necessary, and mixed with the wax release agent, if wax is to be used. The diol mixture and the prepolymer~ by lines 15 and 14, respectively, are brou~ht together in a casting machine 20 in a continuous manner at about 230F.
After thorough mixing of the two ingredients, the mixture is cast out via iine 16 into a casting pan, 30 which is preferably main~
tained at a temperature above 210F. The cast layer can for ex- ~ -ample be l" thick and, after being allowed to set 4 to 5 minutes, can be cut into 3" x 3" chunks, removed and placed in containers~ `
as indicated by line 17 and block 40. A~ter having been aged at 40 ~or a weeX or so the elas~omer can be ground to the size de sired for molding and mixed with whatever additional materials may be desired. Alternatively, the mixture from line 16 can be ex-truded and pelletized to give a moldable composition.
It has also been found that by the addition of catalyst to the mixture in the casting machine 20, the reactions can be speeded up so that polyurethane can be directly cast into a mold to producb a molded product. The catalysts used can be of the ~--513/51~ ~4~ ~ 7 dibutyl-tin-dilaurate, mercaptide or other known type and the casting temperature can be substantially lower~ say 105F, with the mold being at 160-180F.
The ~ollowing table gives e:xamples of the invention prepared according to the illustrated process.
: . . . : . . .......................... . - .
:., .; . ,- . . . . . .. . .. . . . .
-513/518 ~ 7 EX~IP1ES
A B
E PBW E PBW
Modified polyol 0.5 100 0;75 100 PT~EG 0.5 28.24 0.25 9.42 ~I 6.o 85.64 6.o 57.o8 BD0 5.02 26.20 5.02 17.4 Wax ~3 o.63 0.3 -55 Specific Gravity 1.15 1.14 Hardness, Shore D (5 secs) 45 40 Tensile Strength (orig.) 2995 2624 after 70 hrs/212F (-5.0%)2846 (-10.5~)2348 after 7 da/175F/lOO~RH (-11.1%) (-13~3~)2276 -Elongation ~orig.) 537% 503%
after 70 hrs/212aF (_13.8%)463% (-14.5~)430%
a~ter 7 da/175F/lOO~RH(-8.2~)493% (-4.6%)480% `~
Tear Strength (Die C) 507 416 Stiffness @72F 0.5 in lbs. (orig.)Exceeded scale limit 9855 @-20F 3.0 in lbs. 35041 20787 ;
after 70 hrs./212F 0.5 in/lbs Exceeded scale limit (~2.0%)10060 @160F 0.25 in lbs.Exceeded scale limit 5595 Tensile set @200% elongation 62.5% 53.1~o Dart impact-flex @-20F ~FB) as received (no fracture) pass pass after 70 hrs/212F (no fracture) pass pass Stretch test ~250F (4~0 max.) No change 1.6 In the table:
E=number of equivalents PBW=parts by weight FB= a Fisher Body speci~ication .
- - . -.. - . - .. - . ... . . . ... . . ....
7~
The modified polyol w~s Union Carbide Company's NIAX
D-432, a polymer of about 4000 molecular weigh~ made by reacting 80 weight percent o a 2800 molecular ueight poly (oxyalkylene) diol with 20 ~eight percent of a 50/50 (by weigh~) styren0/
acrylonitrile monomer mixture in the presence of a free radical catalyst (a~obisisobutronitrile), as described in Union Carbide's Belgian Patent N~. 788,115. The poly ~oxyalkylene) diol is made by first reacting propylene glyeol with propylene oxide and then subsequently with ethylene oxide so that the chains tarminate in ethylene oxide units. The proportions are such that there are a~out 4.88 propylene oxide units for each ethylene oxide unit.
When the poly (oxyalkylene) diol is reacted with the styrene/
.
acrylonitrile monomer mixture, it appears that some of the two monomers copolymeri~e and add to the diol and some simply - ~-copolymerize ~ithout attaching to the diol but belng intimately ~ -intermixed therewith.
The poly alkylene ether diol was a polytetramethylene ether glycolJ ~PTMEG)~ Polymeg 1000, sold by the Quaker Oats Company~ Chemical Division, Merchandise Mart Plaza, Chicago, ;
Illinois 60545. It has a molecular weight of 1000. E. I. duPont de Nemours Polyglycol 1000 can also be used.
The "MDI" was 4, 4' diph0nylmethane diisocyanate.
The "BDO" was 1, 4-butanediol.
The wax was an ethelyne-bis-steaTamide, Advawax 280F, sold by Cincinnati Milacron Chemical Inc., Reading, Ohio 45215.
Examples of automobile parts that have been made using -~
this thermpolastic urethane and tested with satisfactory results are: General Motors 1974: tl) Riviera Center Sight Shield, Part No. 9694424-439 and ~2) Oldsmobile l'B" Corner Sight Shield, Part No. 9694662-693.
* Trade Mark ~ ' ': . ;
.
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An injection molding-grade thermoplastic polyurethane having good low temperature properties made by reacting the following:
wherein:
said grafted polyol is a 2000 to 5000 molecular weight copolymer of:
(a) 70 to 90 weight percent of a 1000 to 4000 molecular weight poly (oxy C1-C4 alkene)diol, reacted by a free radical polymerization with (b) 10 to 30 weight percent of a monomer mixture of 1 part by weight of a vinylaromatic and 0.1 to 9 parts of an olefinic C2-C6-nitrile, and said polyalkylane ether diol has a molecular weight in the range of 500 to 2500.
wherein:
said grafted polyol is a 2000 to 5000 molecular weight copolymer of:
(a) 70 to 90 weight percent of a 1000 to 4000 molecular weight poly (oxy C1-C4 alkene)diol, reacted by a free radical polymerization with (b) 10 to 30 weight percent of a monomer mixture of 1 part by weight of a vinylaromatic and 0.1 to 9 parts of an olefinic C2-C6-nitrile, and said polyalkylane ether diol has a molecular weight in the range of 500 to 2500.
2. The polyurethane according to claim 1 wherein:
said polyalkane ether diol is a 650 to 1500 molecular weight polytetramethylene ether glycol, said aromatic polyisocyanate is MDI, and said C2-C6 alkane diol is 1, 4 butanediol.
said polyalkane ether diol is a 650 to 1500 molecular weight polytetramethylene ether glycol, said aromatic polyisocyanate is MDI, and said C2-C6 alkane diol is 1, 4 butanediol.
3. The polyurethane according to claim 1 wherein said polyol polyalkane ether diol and aromatic polyisocyanate are first reacted to form a prepolymer having a free NCO in the range of 8 to 12, followed by addition of said C2-C6 alkane diol.
4. The polyurethane of claim 3 wherein the mixture is cast as a slab at a temperature above 210°F, cured for a few days and ground to size for injection molding.
5. An automobile exterior trim component made from the polyurethane of claim 1.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/469,959 US3933938A (en) | 1974-05-15 | 1974-05-15 | Grafted polyether diol-based thermoplastic urethane elastomer |
| US05/469,946 US3933937A (en) | 1974-05-15 | 1974-05-15 | Molding-grade polyurethane |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1063748A true CA1063748A (en) | 1979-10-02 |
Family
ID=27042904
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA225,911A Expired CA1063748A (en) | 1974-05-15 | 1975-04-30 | Molding grade polyurethane |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPS5335836B2 (en) |
| BR (1) | BR7502942A (en) |
| CA (1) | CA1063748A (en) |
| DE (3) | DE2559637A1 (en) |
| ES (1) | ES437394A1 (en) |
| FR (1) | FR2271249A1 (en) |
| GB (1) | GB1505126A (en) |
| IT (1) | IT1035733B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5257296A (en) * | 1975-11-06 | 1977-05-11 | Toyo Tire & Rubber Co Ltd | Polyurethane elastomers with reduced temperature dependence |
| US4049636A (en) * | 1976-02-25 | 1977-09-20 | Uniroyal, Inc. | Thermally stable polyurethane elastomer useful in molding flexible automobile exterior body parts |
| US4041105A (en) * | 1976-02-26 | 1977-08-09 | Uniroyal, Inc. | Polyurethane elastomer derived from graft of ethylenically unsaturated monomer on polyalkylene ether glycol |
| US4125505A (en) | 1976-07-06 | 1978-11-14 | Union Carbide Corporation | Polymer/polyols from high ethylene oxide content polyols |
| JPS6030887Y2 (en) * | 1979-02-02 | 1985-09-17 | 株式会社クボタ | transplant machine |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US987618A (en) * | 1909-12-08 | 1911-03-21 | Theodor De Fontaine | Gas-generator. |
| BE788115A (en) * | 1971-08-30 | 1973-02-28 | Union Carbide Corp | COMPOSITIONS BASED ON A POLYMER AND A POLYOL SUITABLE FOR THE MANUFACTURE OF POLYURETHANE FOAMS |
-
1975
- 1975-04-28 GB GB1752675A patent/GB1505126A/en not_active Expired
- 1975-04-30 CA CA225,911A patent/CA1063748A/en not_active Expired
- 1975-05-02 ES ES75437394A patent/ES437394A1/en not_active Expired
- 1975-05-12 DE DE19752559637 patent/DE2559637A1/en not_active Withdrawn
- 1975-05-12 DE DE19752559636 patent/DE2559636A1/en active Pending
- 1975-05-12 DE DE19752521000 patent/DE2521000A1/en not_active Withdrawn
- 1975-05-13 BR BR7503741A patent/BR7502942A/en unknown
- 1975-05-14 JP JP5718775A patent/JPS5335836B2/ja not_active Expired
- 1975-05-14 FR FR7515073A patent/FR2271249A1/fr not_active Withdrawn
- 1975-05-14 IT IT4960075A patent/IT1035733B/en active
Also Published As
| Publication number | Publication date |
|---|---|
| FR2271249A1 (en) | 1975-12-12 |
| IT1035733B (en) | 1979-10-20 |
| BR7502942A (en) | 1976-03-23 |
| DE2559637A1 (en) | 1977-10-20 |
| GB1505126A (en) | 1978-03-22 |
| JPS5335836B2 (en) | 1978-09-29 |
| ES437394A1 (en) | 1977-02-01 |
| DE2559636A1 (en) | 1977-05-18 |
| JPS511597A (en) | 1976-01-08 |
| DE2521000A1 (en) | 1975-11-20 |
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