CA2201929A1 - Polyurethane composition - Google Patents
Polyurethane compositionInfo
- Publication number
- CA2201929A1 CA2201929A1 CA002201929A CA2201929A CA2201929A1 CA 2201929 A1 CA2201929 A1 CA 2201929A1 CA 002201929 A CA002201929 A CA 002201929A CA 2201929 A CA2201929 A CA 2201929A CA 2201929 A1 CA2201929 A1 CA 2201929A1
- Authority
- CA
- Canada
- Prior art keywords
- isocyanate
- prepolymer
- polyol
- resin mixture
- polymeric polyol
- 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.)
- Abandoned
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
- C08G18/08—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
- C08G2110/00—Foam properties
- C08G2110/0041—Foam properties having specified density
- C08G2110/0066—≥ 150kg/m3
-
- 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
- C08G2350/00—Acoustic or vibration damping material
Landscapes
- 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
A method of producing a polyurethane having a density of from 0.3 to 0.7 g/cc and improved physical and dynamic properties comprising preheating a prepolymer consisting of 4,4'-diphenylmethane di-isocyanate and a polymeric polyol having a molecular weight of at least 1000 and mixing said prepolymer with a resin mixture of a polymeric polyol which may be the same as the first polyol.
Description
POLYURETHANE COMPOSITION
This invention relates to microcellular polyurethane products that have application as engineering components such as spring assisters, buffers, vibration isolators and the like.
Conventional microcellular polyurethane products are manufactured by forming a prepolymer or quasi-prepolyer from the total or partial reaction of a high molecular weight polyhydroxy component such as a polyester or polyether with naphthalene di-isocyanate (NDI). The prepolymer or quasi-prepolymer is then reacted with water, a glycol, a catalyst together with appropriate additives to produce a microcellular material. There are a number of disadvantages with this process particularly associated with the use of NDI. The main disadvantages are:-The limited storage life of the prepolymerformed by the reaction of the polyol with NDI.
The vapour pressure of NDI at the normal processing temperature is sufficiently high to give rise to the emission of toxic vapours.
This invention relates to microcellular polyurethane products that have application as engineering components such as spring assisters, buffers, vibration isolators and the like.
Conventional microcellular polyurethane products are manufactured by forming a prepolymer or quasi-prepolyer from the total or partial reaction of a high molecular weight polyhydroxy component such as a polyester or polyether with naphthalene di-isocyanate (NDI). The prepolymer or quasi-prepolymer is then reacted with water, a glycol, a catalyst together with appropriate additives to produce a microcellular material. There are a number of disadvantages with this process particularly associated with the use of NDI. The main disadvantages are:-The limited storage life of the prepolymerformed by the reaction of the polyol with NDI.
The vapour pressure of NDI at the normal processing temperature is sufficiently high to give rise to the emission of toxic vapours.
2 2 a ~ ~ 2 ~
WO96/11219 pcTlGBs~lo2289 -The relatively long in-mould time required to produce the microcellular polyurethane which leads to high production cost and equipment cost.
The relatively small mixing ratio of lO:l or less of the prepolymer to the chain extender mixture and high difference in viscosity of the two components, coupled with unstable prepolymer, prevents this material from being processed by modern and more efficient techniques such as high pressure impingement mixing and low pressure screw type injection machines in which the liquid mixture can be injected directly into closed moulds.
In order to overcome these disadvantages it has been proposed to use 4,4'-di-phenylmethane di-isocyanate (MDI) in place of the NDI. However, this proposal has not been successful because of high hysteresis losses and poor physical and dynamic properties of products produced to date using MDI.
Attempts have been made to overcome the problems associated with the use of MDI, but to date these have only met with limited success. For example the following limitations have been noted:-Mouldings of satisfactory quality productscould only be obtained on low pressure 220 1~29 metering/dispensing machinery having a high speed stirrer injection type mixing head.
Satisfactory mouldings with a short in-mould time of 5 minutes or less could only be produced in a very limited part weight range and limited range of densities. Variation of mixing head speed or volume of dispensing machine did not overcome the problem.
Moulded products made by casting or pouring method and by high pressure impingement mixing had inferior compression set and inferior performance under dynamic compressive stress.
Optimum processing conditions and a highly efficient production process with low demould times was not compatible with the equivalent ratio of isocyanate group to isocyanate reacting compounds in the range of 0.85 to 1.5:1 required to achieve the desired physical and dynamic properties.
Given a certain level of blowing agent and catalyst level only a limited range of densities could be moulded from one compound, therefore, limiting the size and type of component which could be moulded from a given compound.
WO96/11219 r 2 ~ O ~ 9 ~ 9 PcTlGB95lo228s -Generally, springs assisters, buffer and jounce bumpers made of microcellular polyurethane have highly complex internal and external configuration, frequently having deep undercuts on the innerbore which requires the material to acquire a very high green strength prior to the polymerification process being completed to enable the mould core pin to be withdrawn by stretching the component by over 300%, without splitting, within 2 to 5 minutes of the liquid material being poured or injected into the mould.
Spring assisters in motor vehicles suspension applications are also required to meet very precise stress strain characteristics, which means that the density and modulus of the material must be controlled within very close limits. With conventional processes this can only be achieved with a limited number of moulding techniques.
It has been discovered by scanning electron microscopy that most of the above disadvantages result from anisotropy of the microcellular foams produced using existing recipes and processes. An empirical definition of anisotropy is "A lack of spherical quality of the cells of the foam~
WO 96/11219 PCT/~,;Dg'J~89 The present invention has been made in order to overcome the above disadvantages.
.~
Careful attention to the reacting equivalency of the resin mixture, among other aspects of the invention, produces closer to ideal isotropic cell structure.
According to the invention there is provided a method of manufacturing a microcellular polyurethane comprising reacting a polymeric polyol having a molecular weight of at least 1000, a diol or ~;~m;ne having from 2 to 20 carbon atoms and 4,4~-di-phenylmethane di-isocyanate (MDI) to produce a polyurethane having a density of from 0.3 to 0.7 g/cc.
In a preferred embodiment of the invention a prepolymer or quasi-prepolymer is formed from the polymeric polyol which is preferably a diol, triol or tetrol having a molecular weight of at least 1000 and the MDI. The prepolymer is then reacted with a resin mixture formed from a pclymeric polyol which is preferably the same as the polymeric polyol used to form the prepolymer and the diol or diamine having 2 to 20 carbons. The resin mixture may also include additives such as chain extenders, catalysts, surface active agents, blowing agents and the like. The 2 2 ~
WO96/11219 PCT/GB95/02289 ~
equivalent weight of the resin mixture, expressed as mg of KOH per gram of material is preferably in the range 200 to 300.
A preferred procedure for carrying out the invention to produce moulded products is as follows:-Pre-heating (i) a prepolymer comprising the di-isocyanate and a polymeric polyol and (ii) a resin mixture of a polymeric polyol together with a diol or diamine having from 2 to 20 carbons, a chain extender, one or more catalysts, one or more surface-active agents, a blowing agent and other additives as may be required by technical or commercial considerations.
Metering under pressure the prepolymer (i) and the resin (ii) to a mixing apparatus.
Mixing the prepolymer (i) and the resin (ii) in the said mixing device either by a high speed stirrer enclosed in a chamber or by high pressure impingement mixing known as RIM technique.
Injecting the required amount of the liquid mixture at a given ratio into a closed or open heated mould.
220~29 WO 96/11219 P~ ,;b95/02289 Reacting the said component in the heated mould until a consistent polymer is formed which can then be demoulded after a comparatively short time, prior to curing for example in an oven.
The injection moulded component may require no after treatment other than to remove sprue.
The polymeric polyol is, as already stated, one having a molecular weight of at least 1000, preferably about 2000. Preferred polymeric polyols are difunctional polyester polyols having an equivalent weight of about 110, such as poly (hexamethylene) adipate, poly (butylene) adipate and poly (epsilon caprolactone), and polyether polyols such as poly (propylene) oxide and poly (tetramethylene) glycol. Combinations and co-polymers of more than one polymeric polyol can be used if desired.
The di-isocyanate used in the invention is preferably an alkyl or aryl substituted alkyl di-isocyanate such as 4,4'-diphenylmethane di-- isocyanate (MDI). The MDI can be the pure form or one or more of the so-called modified forms. The amounts of di-isocyanate and polyol used are preferably in the molar range 2:1 to 5:1, more partlcularly 2.4:1 to 5:1 di-isocyanate to polyol.
~ ~ o ~
WO96/11219 pcTlGB95lo228s '-The preferred range of isocyanate groups to isocyanate reacting compounds is from 0.85:1 to 1.15:1.
Additives which are preferably included in the reaction mixture include one or more catalysts which are preferably secondary or tertiary amines, organometallic compounds such as organic tin compounds. By choosing the appropriate catalyst the cure time in the mould can be varied from twenty minutes to about three minutes. Using the same catalyst type the density of the product can be adjusted within the range 0.35 to 0.70 g/cc.
Particularly preferred catalysts include an amine salt sold under the name ''Dabcoll 33LV and an organotin compound sold under the name "Dabco" F12CL.
Other additives include sufactants, preferably non-silicone surfactants (because use of silicone will detract from the achievements of isotropy of the cells), antioxidants, bacteriostatic compounds and pigments. In the Examples all parts or percentages are by weight.
EXAMPLE I
A quasi-prepolymer containing 20 to 22 wt~
isocyanate group was prepared by the reaction between a polycaprolactone having an equivalent weight of ~ WO96/11219 PCT/GB95/02289 approximately llO0 and 4,4'-diphenylmethane di-isocyanate. The prepolymer was kept at a temperature of 42OC.
A resin mixture of the above polyester, 1,4-butane diol, water, tertiary amine catalyst, organometallic tin catalyst and a surface active agent was prepared and maintained at a temperature of 45OC. The resin mixture was formulated to give an equivalent weight of 270.
lO0 parts by weight of the ~uasi-prepolymer were reacted with 106 parts of the resin mixture using low pressure and high pressure metering/mixing machines. The mixture was injected into closed moulds at a temperature of 60OC to produce a spring aid and test plates.
EXAMPLE II
The process of Example I was repeated, but a polyol (resin) mixture having an equivalent weight of 230 and with ll2 parts of prepolymer was mixed with lO0 parts of polyol mixture (resin). Mouldings were produced as in Example I.
The density of the material was 250 kg/m3 (moulded parts having a density of 450, 550 and WO96/11219 2 2 0 1 ~ 2 9 PCTIGBgS/02289 ~
650 kg/m3 could easily be produced from the same mixture with a demould time of less than 5 minutes).
The mouldings were then post cured for 12 hours at 900C.
EXAMPLE III
A quasi-prepolymer containing 14 to 16 wt%
isocyanate groups was prepared by the reaction between a polyether glycol (PTMEG) having 2n equivalent weight of approximately llO0 and 4,4'-diphenylmethane di-isocyanate. The quasi-prepolymer was kept at a temperature of 40OC.
A resin mixture of the above polyether l,4-butane diol, water, tertiary amine catalyst, organometallic tin catalyst and a surface active agent was prepared and mai~tained at a temperature of 40OC. The resin mixture was formulated to give an equivalent weight of 260.
112 parts by weight of the quasi-prepolymer were reacted with 100 parts of the polyol mixture using low pressure and high pressure metering/mixing machines. The mixture was injected into closed moulds at a temperature of 60OC to produce a spring aid and test plates.
The density of the material was 260 kg/m'.
(Moulded parts having a density of 450, 550 and 650 kg/m3 could easily be produced from the same mixture with a demould time of less than 5 minutes).
The mouldings were then post cured for 6 hours at 900C.
EXAMPLE IV
A quasi-prepolymer containing 14 to 16 wt%
isocyanate group was prepared by the reaction between a polyethylene/butylene adipate having an equivalent weight of approximately lO50 and 4,4'-diphenylmethane di-isocyanate. The prepolymer was kept at a temperature of 40OC.
A mixture of the above polyester linear and branched, l,4-butane diol, water, tertiary amine catalyst, organometallic tin catalyst and surface active agent was pre-poured and maintained at 40OC.
The above mixture was formulated to give an equivalent weight of 240.
lO0 parts by we1ght of the quas1-prepolymer mixture were reacted with 85 parts of the polyol mixture using low pressure and high pressure metering/mixing machines. The mixture from the O96111219 ~ 2 ~ ~ 9 2 ~ pcTlGB9slo228s machine was injected into closed moulds at a temperature of 60OC to produce a spring aid and test plates.
The density of the free foam was 230 kg/m3.
(Moulded parts having a density of 450,550 and 650 kg/m3 could easily be produced from the same mixture with a demould time of less than 5 minutes). The mouldings were then post-cured for 16 hours at 90OC.
The products made in accordance with the above Examples were maintained at ambient temperature for a week and then the physical properties thereof were measured. The results are shown in the following table.
EXA~qPLE 1 2 3 4 TEST METHOD
Free Eoam Density kg/m3 250 250 260 230 DIN 53420 MouldPart Density kg/m3 450 450 450 450 DIN 53420 Tensile Strength MPa 5.5 6.0 4.5 . 5 DIN 53571 Elongation at sreak % 450 430 400 400 DIN 53571 Tear Strength N/mm 14.416 14.0 17.0 DIN 53515 compression Set 22 hrs at 50 % comp. at 70 ~ C % 7 7 - 5 10.0 9.4 DIN 53572 Rebound Resilience % 60 55 50 35 BS 903 Part A8 /B
2 2 0 ~ 9 2 Dynamic fatigue test.
A dynamic fatigue test was carried out on a ,--~moulded product as illustrated in the accompanying ~ /
drawing which shows an axial section through a typical spring assistor for a motor vehicle suspension. The part was made in each of the Example formulations. The part density was approximately 500 kg/m3.
The test comprised 200,000 compression cycles at 2HZ at a load of 4KN. On completion of test, the part showed that the permanent set did not exceed 5%
and there was no evidence of any splits or cracks, internally or externally.
With the invention microcellular polyurethane products and particularly vehicle suspensions, spring aids and jounce bumpers can be obtained in any desired internal and external configuration using high or low pressure liquid injection moulding technique, casting or othe~ fluid moulding techniques.
In particular, an advantage of the invention is that by the use of any of the conventional polyurethane dispensing machinery, articles can be produced by introducing the liquid mixture into -2~ 192Q
closed moulds, thus atmospheric contamination by di-isocyanates can be more easily controlled and also the production cycle time can be reduced without incurring other processing penalties.
Moreover the invention permits the production of a wide range of part weights and configurations over a range of densities from 0.45 to 0.70 cc without any changes or adjustment to the process parameters or to the reacting mixtures.
Together with these advantages, the physical and dynamic properties of the moulded products are of a level which have not been achieved hitherto with MDI
as the isocyanate.
WO96/11219 pcTlGBs~lo2289 -The relatively long in-mould time required to produce the microcellular polyurethane which leads to high production cost and equipment cost.
The relatively small mixing ratio of lO:l or less of the prepolymer to the chain extender mixture and high difference in viscosity of the two components, coupled with unstable prepolymer, prevents this material from being processed by modern and more efficient techniques such as high pressure impingement mixing and low pressure screw type injection machines in which the liquid mixture can be injected directly into closed moulds.
In order to overcome these disadvantages it has been proposed to use 4,4'-di-phenylmethane di-isocyanate (MDI) in place of the NDI. However, this proposal has not been successful because of high hysteresis losses and poor physical and dynamic properties of products produced to date using MDI.
Attempts have been made to overcome the problems associated with the use of MDI, but to date these have only met with limited success. For example the following limitations have been noted:-Mouldings of satisfactory quality productscould only be obtained on low pressure 220 1~29 metering/dispensing machinery having a high speed stirrer injection type mixing head.
Satisfactory mouldings with a short in-mould time of 5 minutes or less could only be produced in a very limited part weight range and limited range of densities. Variation of mixing head speed or volume of dispensing machine did not overcome the problem.
Moulded products made by casting or pouring method and by high pressure impingement mixing had inferior compression set and inferior performance under dynamic compressive stress.
Optimum processing conditions and a highly efficient production process with low demould times was not compatible with the equivalent ratio of isocyanate group to isocyanate reacting compounds in the range of 0.85 to 1.5:1 required to achieve the desired physical and dynamic properties.
Given a certain level of blowing agent and catalyst level only a limited range of densities could be moulded from one compound, therefore, limiting the size and type of component which could be moulded from a given compound.
WO96/11219 r 2 ~ O ~ 9 ~ 9 PcTlGB95lo228s -Generally, springs assisters, buffer and jounce bumpers made of microcellular polyurethane have highly complex internal and external configuration, frequently having deep undercuts on the innerbore which requires the material to acquire a very high green strength prior to the polymerification process being completed to enable the mould core pin to be withdrawn by stretching the component by over 300%, without splitting, within 2 to 5 minutes of the liquid material being poured or injected into the mould.
Spring assisters in motor vehicles suspension applications are also required to meet very precise stress strain characteristics, which means that the density and modulus of the material must be controlled within very close limits. With conventional processes this can only be achieved with a limited number of moulding techniques.
It has been discovered by scanning electron microscopy that most of the above disadvantages result from anisotropy of the microcellular foams produced using existing recipes and processes. An empirical definition of anisotropy is "A lack of spherical quality of the cells of the foam~
WO 96/11219 PCT/~,;Dg'J~89 The present invention has been made in order to overcome the above disadvantages.
.~
Careful attention to the reacting equivalency of the resin mixture, among other aspects of the invention, produces closer to ideal isotropic cell structure.
According to the invention there is provided a method of manufacturing a microcellular polyurethane comprising reacting a polymeric polyol having a molecular weight of at least 1000, a diol or ~;~m;ne having from 2 to 20 carbon atoms and 4,4~-di-phenylmethane di-isocyanate (MDI) to produce a polyurethane having a density of from 0.3 to 0.7 g/cc.
In a preferred embodiment of the invention a prepolymer or quasi-prepolymer is formed from the polymeric polyol which is preferably a diol, triol or tetrol having a molecular weight of at least 1000 and the MDI. The prepolymer is then reacted with a resin mixture formed from a pclymeric polyol which is preferably the same as the polymeric polyol used to form the prepolymer and the diol or diamine having 2 to 20 carbons. The resin mixture may also include additives such as chain extenders, catalysts, surface active agents, blowing agents and the like. The 2 2 ~
WO96/11219 PCT/GB95/02289 ~
equivalent weight of the resin mixture, expressed as mg of KOH per gram of material is preferably in the range 200 to 300.
A preferred procedure for carrying out the invention to produce moulded products is as follows:-Pre-heating (i) a prepolymer comprising the di-isocyanate and a polymeric polyol and (ii) a resin mixture of a polymeric polyol together with a diol or diamine having from 2 to 20 carbons, a chain extender, one or more catalysts, one or more surface-active agents, a blowing agent and other additives as may be required by technical or commercial considerations.
Metering under pressure the prepolymer (i) and the resin (ii) to a mixing apparatus.
Mixing the prepolymer (i) and the resin (ii) in the said mixing device either by a high speed stirrer enclosed in a chamber or by high pressure impingement mixing known as RIM technique.
Injecting the required amount of the liquid mixture at a given ratio into a closed or open heated mould.
220~29 WO 96/11219 P~ ,;b95/02289 Reacting the said component in the heated mould until a consistent polymer is formed which can then be demoulded after a comparatively short time, prior to curing for example in an oven.
The injection moulded component may require no after treatment other than to remove sprue.
The polymeric polyol is, as already stated, one having a molecular weight of at least 1000, preferably about 2000. Preferred polymeric polyols are difunctional polyester polyols having an equivalent weight of about 110, such as poly (hexamethylene) adipate, poly (butylene) adipate and poly (epsilon caprolactone), and polyether polyols such as poly (propylene) oxide and poly (tetramethylene) glycol. Combinations and co-polymers of more than one polymeric polyol can be used if desired.
The di-isocyanate used in the invention is preferably an alkyl or aryl substituted alkyl di-isocyanate such as 4,4'-diphenylmethane di-- isocyanate (MDI). The MDI can be the pure form or one or more of the so-called modified forms. The amounts of di-isocyanate and polyol used are preferably in the molar range 2:1 to 5:1, more partlcularly 2.4:1 to 5:1 di-isocyanate to polyol.
~ ~ o ~
WO96/11219 pcTlGB95lo228s '-The preferred range of isocyanate groups to isocyanate reacting compounds is from 0.85:1 to 1.15:1.
Additives which are preferably included in the reaction mixture include one or more catalysts which are preferably secondary or tertiary amines, organometallic compounds such as organic tin compounds. By choosing the appropriate catalyst the cure time in the mould can be varied from twenty minutes to about three minutes. Using the same catalyst type the density of the product can be adjusted within the range 0.35 to 0.70 g/cc.
Particularly preferred catalysts include an amine salt sold under the name ''Dabcoll 33LV and an organotin compound sold under the name "Dabco" F12CL.
Other additives include sufactants, preferably non-silicone surfactants (because use of silicone will detract from the achievements of isotropy of the cells), antioxidants, bacteriostatic compounds and pigments. In the Examples all parts or percentages are by weight.
EXAMPLE I
A quasi-prepolymer containing 20 to 22 wt~
isocyanate group was prepared by the reaction between a polycaprolactone having an equivalent weight of ~ WO96/11219 PCT/GB95/02289 approximately llO0 and 4,4'-diphenylmethane di-isocyanate. The prepolymer was kept at a temperature of 42OC.
A resin mixture of the above polyester, 1,4-butane diol, water, tertiary amine catalyst, organometallic tin catalyst and a surface active agent was prepared and maintained at a temperature of 45OC. The resin mixture was formulated to give an equivalent weight of 270.
lO0 parts by weight of the ~uasi-prepolymer were reacted with 106 parts of the resin mixture using low pressure and high pressure metering/mixing machines. The mixture was injected into closed moulds at a temperature of 60OC to produce a spring aid and test plates.
EXAMPLE II
The process of Example I was repeated, but a polyol (resin) mixture having an equivalent weight of 230 and with ll2 parts of prepolymer was mixed with lO0 parts of polyol mixture (resin). Mouldings were produced as in Example I.
The density of the material was 250 kg/m3 (moulded parts having a density of 450, 550 and WO96/11219 2 2 0 1 ~ 2 9 PCTIGBgS/02289 ~
650 kg/m3 could easily be produced from the same mixture with a demould time of less than 5 minutes).
The mouldings were then post cured for 12 hours at 900C.
EXAMPLE III
A quasi-prepolymer containing 14 to 16 wt%
isocyanate groups was prepared by the reaction between a polyether glycol (PTMEG) having 2n equivalent weight of approximately llO0 and 4,4'-diphenylmethane di-isocyanate. The quasi-prepolymer was kept at a temperature of 40OC.
A resin mixture of the above polyether l,4-butane diol, water, tertiary amine catalyst, organometallic tin catalyst and a surface active agent was prepared and mai~tained at a temperature of 40OC. The resin mixture was formulated to give an equivalent weight of 260.
112 parts by weight of the quasi-prepolymer were reacted with 100 parts of the polyol mixture using low pressure and high pressure metering/mixing machines. The mixture was injected into closed moulds at a temperature of 60OC to produce a spring aid and test plates.
The density of the material was 260 kg/m'.
(Moulded parts having a density of 450, 550 and 650 kg/m3 could easily be produced from the same mixture with a demould time of less than 5 minutes).
The mouldings were then post cured for 6 hours at 900C.
EXAMPLE IV
A quasi-prepolymer containing 14 to 16 wt%
isocyanate group was prepared by the reaction between a polyethylene/butylene adipate having an equivalent weight of approximately lO50 and 4,4'-diphenylmethane di-isocyanate. The prepolymer was kept at a temperature of 40OC.
A mixture of the above polyester linear and branched, l,4-butane diol, water, tertiary amine catalyst, organometallic tin catalyst and surface active agent was pre-poured and maintained at 40OC.
The above mixture was formulated to give an equivalent weight of 240.
lO0 parts by we1ght of the quas1-prepolymer mixture were reacted with 85 parts of the polyol mixture using low pressure and high pressure metering/mixing machines. The mixture from the O96111219 ~ 2 ~ ~ 9 2 ~ pcTlGB9slo228s machine was injected into closed moulds at a temperature of 60OC to produce a spring aid and test plates.
The density of the free foam was 230 kg/m3.
(Moulded parts having a density of 450,550 and 650 kg/m3 could easily be produced from the same mixture with a demould time of less than 5 minutes). The mouldings were then post-cured for 16 hours at 90OC.
The products made in accordance with the above Examples were maintained at ambient temperature for a week and then the physical properties thereof were measured. The results are shown in the following table.
EXA~qPLE 1 2 3 4 TEST METHOD
Free Eoam Density kg/m3 250 250 260 230 DIN 53420 MouldPart Density kg/m3 450 450 450 450 DIN 53420 Tensile Strength MPa 5.5 6.0 4.5 . 5 DIN 53571 Elongation at sreak % 450 430 400 400 DIN 53571 Tear Strength N/mm 14.416 14.0 17.0 DIN 53515 compression Set 22 hrs at 50 % comp. at 70 ~ C % 7 7 - 5 10.0 9.4 DIN 53572 Rebound Resilience % 60 55 50 35 BS 903 Part A8 /B
2 2 0 ~ 9 2 Dynamic fatigue test.
A dynamic fatigue test was carried out on a ,--~moulded product as illustrated in the accompanying ~ /
drawing which shows an axial section through a typical spring assistor for a motor vehicle suspension. The part was made in each of the Example formulations. The part density was approximately 500 kg/m3.
The test comprised 200,000 compression cycles at 2HZ at a load of 4KN. On completion of test, the part showed that the permanent set did not exceed 5%
and there was no evidence of any splits or cracks, internally or externally.
With the invention microcellular polyurethane products and particularly vehicle suspensions, spring aids and jounce bumpers can be obtained in any desired internal and external configuration using high or low pressure liquid injection moulding technique, casting or othe~ fluid moulding techniques.
In particular, an advantage of the invention is that by the use of any of the conventional polyurethane dispensing machinery, articles can be produced by introducing the liquid mixture into -2~ 192Q
closed moulds, thus atmospheric contamination by di-isocyanates can be more easily controlled and also the production cycle time can be reduced without incurring other processing penalties.
Moreover the invention permits the production of a wide range of part weights and configurations over a range of densities from 0.45 to 0.70 cc without any changes or adjustment to the process parameters or to the reacting mixtures.
Together with these advantages, the physical and dynamic properties of the moulded products are of a level which have not been achieved hitherto with MDI
as the isocyanate.
Claims (15)
1. A method of manufacturing a microcellular polyurethane comprising reacting a polymeric polyol having a molecular weight of at least 1000, a diol or diamine having from 2 to 20 carbon atoms and 4,4'-di-phenylmethane di-isocyanate to produce a polyurethane having a density of from 0.3 to 0.7 g/cc.
2. A method as claimed in Claim 1, wherein a prepolymer is formed from the polymeric polyol and di-isocyanate and the prepolymer is reacted with a resin mixture formed from a second polymeric polyol and the diol or diamine.
3. A method as claimed in Claim 2, wherein the second polymeric polyol is the same as the first polymeric polyol.
4. A method as claimed in Claim 2 or Claim 3, wherein the equivalent weight of the resin mixture, expressed as mg of KOH per gram of material is in the range 200 to 300.
5. A method as claimed in any of claims 2 to 4, wherein additives are included in the reaction mixture, preferably in the resin mixture.
6. A method as claimed in any of Claims 2 to 5, wherein the prepolymer and the resin mixture are metered under pressure to a mixing apparatus.
7. A method as claimed in Claim 6, wherein mixing is effected by a high speed stirrer enclosed in a chamber or by high pressure impingement.
8. A method as claimed in any of Claims 2 to 7, wherein the mixed prepolymer and resin mixture is supplied to a mould.
9. A method as claimed in Claim 8, wherein the mould is heated to form a consistent polymer.
10. A method as claimed in Claim 9, wherein the product removed from the mould is cured.
11. A method as claimed in any preceding claim, wherein the di-isocyanate and polyol are used in the molar range 2:1 to 5:1 and preferably in the molar range 2.4:1 to 5:1.
12. A method as claimed in any preceding claim, wherein the range of isocyanate groups to isocyanate reacting compounds is from 0.85:1 to 1.15:1.
13. A method as claimed in any preceding claim, wherein the di-isocyanate is an alkyl, or aryl substituted, di-isocyanate.
14. A method as claimed in Claim 13 wherein the di-isocyanate is 4,4'-diphenylmethane di-isocyanate.
15. A method as claimed in any preceding claim, wherein the polymeric polyol is a polyester polyol having an equivalent weight of about 110.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9420107A GB9420107D0 (en) | 1994-10-05 | 1994-10-05 | Polyurethane composition |
| GB9420107.6 | 1994-10-05 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2201929A1 true CA2201929A1 (en) | 1996-04-18 |
Family
ID=10762399
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002201929A Abandoned CA2201929A1 (en) | 1994-10-05 | 1995-09-27 | Polyurethane composition |
Country Status (11)
| Country | Link |
|---|---|
| EP (1) | EP0784640A1 (en) |
| JP (1) | JPH10507218A (en) |
| KR (1) | KR970706325A (en) |
| CN (1) | CN1167494A (en) |
| AU (1) | AU3530895A (en) |
| BR (1) | BR9509282A (en) |
| CA (1) | CA2201929A1 (en) |
| CZ (1) | CZ103997A3 (en) |
| GB (1) | GB9420107D0 (en) |
| PL (1) | PL319722A1 (en) |
| WO (1) | WO1996011219A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU2002225369A1 (en) * | 2000-12-27 | 2002-07-08 | Hitachi Chemical Co., Ltd. | Photobase generators, curable compositions prepared by using the same and process of curing |
| JP4459711B2 (en) * | 2004-05-12 | 2010-04-28 | 日本ポリウレタン工業株式会社 | Rail pad manufacturing method |
| DE102005008242A1 (en) * | 2005-02-22 | 2006-08-24 | Basf Ag | Cylindrical molded bodies, useful in automobile parts e.g. auxiliary springs, buffer, short arm-bearing, comprises cellular polyurethane elastomers with determined density, tensile strength, breach extension and tear resistance |
| DE102005008263A1 (en) * | 2005-02-22 | 2006-08-24 | Basf Ag | Preparation of cylindrical molded bodies, useful in automobiles e.g. springs, comprises reaction of prepolymers based on methylenediphenyldiisocyanate with cross linking components based on polyetheralcohol, diols, water and catalysts |
| WO2009112576A1 (en) * | 2008-03-14 | 2009-09-17 | Basf Se | Coarse-cell polyurethane elastomers |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1534551A (en) * | 1966-12-06 | 1968-07-26 | Elastomer Ag | Process for obtaining highly elastic, tear-resistant and cold-resistant cellular polyurethane materials having a relatively high specific weight |
| US3856716A (en) * | 1971-03-10 | 1974-12-24 | Laporte Industries Ltd | High density polyurethane foams |
| GB1453794A (en) * | 1974-01-11 | 1976-10-27 | Interox Chemicals Ltd | Polyurethane foams |
| DE2940856A1 (en) * | 1979-10-09 | 1981-04-23 | Elastogran GmbH, 2844 Lemförde | METHOD FOR THE PRODUCTION OF POLYURETHANE ELASTOMERS WHICH MAY CONTAIN CELLS |
| IT1240635B (en) * | 1990-05-04 | 1993-12-17 | Dow Italia | MICROCELLULAR POLYURETHANE POLYMERS PREPARED FROM THREE POLY POLYMERS (TETRAMETHYLENE) GLYCOLS WITH ISOCYANATE GROUPS TERMINALS |
| DE4102174A1 (en) * | 1991-01-25 | 1992-07-30 | Basf Ag | METHOD FOR THE PRODUCTION OF CELLED POLYURETHANE ELASTOMERS USING POLYETHERCARBONATE DIOLES AS THE STARTING COMPONENT |
-
1994
- 1994-10-05 GB GB9420107A patent/GB9420107D0/en active Pending
-
1995
- 1995-09-27 BR BR9509282A patent/BR9509282A/en not_active Application Discontinuation
- 1995-09-27 PL PL95319722A patent/PL319722A1/en unknown
- 1995-09-27 CA CA002201929A patent/CA2201929A1/en not_active Abandoned
- 1995-09-27 JP JP8512402A patent/JPH10507218A/en active Pending
- 1995-09-27 AU AU35308/95A patent/AU3530895A/en not_active Abandoned
- 1995-09-27 WO PCT/GB1995/002289 patent/WO1996011219A1/en not_active Application Discontinuation
- 1995-09-27 CN CN95196447A patent/CN1167494A/en active Pending
- 1995-09-27 EP EP95932132A patent/EP0784640A1/en not_active Ceased
- 1995-09-27 CZ CZ971039A patent/CZ103997A3/en unknown
-
1997
- 1997-04-07 KR KR1019970702259A patent/KR970706325A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| JPH10507218A (en) | 1998-07-14 |
| GB9420107D0 (en) | 1994-11-16 |
| CN1167494A (en) | 1997-12-10 |
| CZ103997A3 (en) | 1997-11-12 |
| BR9509282A (en) | 1997-11-18 |
| PL319722A1 (en) | 1997-08-18 |
| EP0784640A1 (en) | 1997-07-23 |
| KR970706325A (en) | 1997-11-03 |
| AU3530895A (en) | 1996-05-02 |
| WO1996011219A1 (en) | 1996-04-18 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |