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
  • C08G18/30—Low-molecular-weight compounds
  • C08G18/32—Polyhydroxy compounds; Polyamines; Hydroxyamines
  • C08G18/3271—Hydroxyamines
• • 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
  • C08G18/77—Polyisocyanates or polyisothiocyanates having heteroatoms in addition to the isocyanate or isothiocyanate nitrogen and oxygen or sulfur
  • C08G18/78—Nitrogen
  • C08G18/79—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates
  • C08G18/797—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates containing carbodiimide and/or uretone-imine 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
  • C08G2120/00—Compositions for reaction injection moulding processes

Definitions

• the present invention relates to a composition which has a first component, comprising a compound which is substituted with at least a hydroxyl group and an amine group, and a second component, comprising a polyisocyanate, and, optionally, a third component.
• Such a composition can be used to produce polyurethanes.
• Ethanolamines can also be added to urethane systems as chain lengtheners.
• Other substances for example, aromatic diamines, are also used as chain lengtheners.
• the resin mixture consists of a molecule with a high molecular weight that is lengthened using a few molecules with a low molecular weight, before it forms cross links with a polyisocyanate. This does not delay the rapid increase in viscosity which causes the problems noted previously.
• the exclusive use of compounds of low molecular weight such as ethanolamine presents the drawback that the chain length between two reacted groups is very short. This may adversely affect the mechanical properties of the product.
• Ethanolamines can also be added to urethane systems as crosslinking agent. This is e.g. described in US Patent 3,296,156, which describes only 2-amino-2-methyl-propanol. This is further described in US Patent 3,395,129, which describes the use of quaternizable tertiairy amino groups for crosslinking polyurethanes.
• the groups in this US Patent are always present in an amount of at least 2 per molecule and the crosslinking agents always have a molecular weight below 500.
• EP-A-314,347 describes a composition that contains polyisocyanates and isocyanate-reactive compounds.
• the composition contains an isocyanate-reactive compound with a low molecular weight, for example, ethanolamine.
• the ethanolamine is used only as a chain lengthener.
• the European Patent does not describe the particular advantages of using a composition that contains a compound that comprises approximately 1 amino group per molecule, according to the invention.
• US Patent 4,420,600 describes polyurethane elastomers from hindered aliphatic diisocyanates. They describe a composition containing low molecular weight aminodiols. Such a composition would not give the possibilities that a composition according to the present invention gives.
• urethane-urea systems are based on diols, diamines and/or mixtures of the two.
• a diol/polyisocyanate system is too slow, whereas a diamine/polyisocyanate system is too fast.
• the drawback to adding large amounts of such catalysts is that the thermal stability of the product is adversely affected because at high temperatures the reverse reaction is catalysed. This results in decomposition of the polymer.
• the diamines will react quickly with the polyiso ⁇ cyanates at the beginning of the reaction to form a product of high molecular weight or a three-dimensional network. This will cause the viscosity to increase to such an extent as to prevent efficient wetting of the fibres.
• the present invention provides a composition which has a low viscosity, and whose viscosity does not increase rapidly during the initial portion of a polymerization process.
• the present composition comprises a first component which is an amine and hydroxy substituted compound, and a second component, which is a polyisocyanate.
• the compound used in the first component has a molecular weight between 150 and 2000, and the number of amino groups on virtually all of the molecules is one.
• a further embodiment of the present invention is a process for moulding using the presently claimed - 4 -
• An additional embodiment of the present invention is an article formed by polymerization of the presently claimed invention.
• the aim of the present invention is to provide a composition with a low viscosity which can set within a reasonable amount of time.
• the viscosity of the composition should not increase too rapidly during the initial phase of the setting process.
• the desired rate of viscosity increase is achieved according to the present invention because the first component consists of a compound with a molecular weight of between 150 and 2000, with the number of amino groups in virtually all of the molecules of the first component being 1. Amino groups react with isocyanate groups faster than hydroxyl groups do. This forms oligomers during the initial polymerization, because the polyisocyanate has reacted with the amino group of one or more of the hydroxylamino compounds.. This oligomer continues to polymerize, or to form cross link, via the hydroxyl groups and a network may be formed. Because the initial oligomer has a relatively low molecular weight, the composition retains a low viscosity. This enables the composition to still be capable of wetting fibrous material during the setting process.
• the first component according to the invention contains virtually no molecules with an amino functionality of 2 or more, because at such a level of functionality the viscosity of the composition would increase too rapidly.
• the amino group may be a primary or a secondary amino.
• the compound used as the first component may be an aliphatic or an aromatic group.
• the molecular weight of the compound which is used as the first component is preferably between 165 and 1000, more preferably between 500 and 1000.
• the average amine functionality of the first component is 0.75-1.1, preferably 0.9-1.05.
• the average hydroxyl functionality of the first component is preferably between 1 and 6, more preferably between 1 and 3.
• the amine functionality is the number of amine groups per molecule.
• the hydroxy functionality is the number of hydroxyl groups per molecule.
• An example of a first component according to the invention is the compound of the following formula: H 2 N-CH 2 CH 2 CH 2 -O-CH j CH j -O-CH j C ⁇ -OH.
• a second example of the first compound according to the invention is the reaction product of equivalent amounts of ethanol amine with adipic acid and a diamine such as Jeffamine JAD 2000 from Texaco.
• Jeffamine JAD2000 is a polypropoxydiamine with a molecular weight of 2000.
• the reaction product is a mixture of 25% diamine, 25% diol and 50% alkanolamine.
• the alkanolamine should be separated from the two other compounds by a purification step.
• a third example of a known process for the production of hydroxylamines is the reaction of a diol with acrylonitrile. The nitrile group is hydrogenated to form an amino group. A reasonably pure hydroxylamine can be obtained by destination of the reaction product. Polyglycolamine H163 from Union-Carbide is produced according to this third example.
• the fourth way comprises reacting phthalic anhydride and a low molecular weight alkanolamine, such as ethanolamine.
• a low molecular weight alkanolamine such as ethanolamine.
• N-hydroxyethyl phthalic anhydride is used.
• the reaction product is N-hydroxyethylphthalic amide (HPI).
• HPI N-hydroxyethylphthalic amide
• the imide is reacted with an amount of oxirane, such as ethyleneoxide or propyleneoxide, until a desired molecular weight is obtained.
• a low amount of alkoxide may be present as a catalyst.
• the phthaloylgroup is removed. This process results in a polyalkoxy chain with one amino and one hydroxylgrou .
• the first compound should contain less than 5 mol% molecules with more than one amino group per molecule, and preferably contains less than 1 mol% molecules with more than one amino group per molecule. Most preferably, the first compound does not comprise molecules with more than one amino group.
• the phrases 'alkanolamine' and 'hydroxyla ine' can be used interchangeably with respect to the present invention.
• the molecular weight described in this text is the number averaged molecular weight Mn, as given by the producer of a compound, as described from the ratio of the constituent reactants or as measured with proton-NMR.
• the viscosity of a composition according to the present invention is lower than 1000 mPas, preferably lower than 150 mPas at 23°C.
• the viscosity is measured immediately after the mixing of the components, using a Hake viscometer of type HBTD, spindle 1 , 100 rpm.
• the low viscosity is particularly advantageous when processing methods, such as the so-called reaction injection moulding method (RIM method), are used.
• the low viscosity composition according to the present invention is advantageous in the production of fibre-reinforced and/or filled half products (prepregs or moulding compounds such as sheet moulding compound (SMC)), as the fibres or fillers are better wetted by the mixture of low viscosity.
• the invention relates to a method for using a composition as described above, for reaction injection moulding (RIM), reinforced reaction injection moulding (RRIM) and, preferably, for structural reaction injection moulding (SRIM).
• RIM is a method whereby a mixture is injected into a mould and sets within a short time after injection.
• RRIM is a RIM method whereby the mixture also contains fibrous reinforcing material.
• SRIM is a RIM method whereby a fibrous reinforcing material is already in the mould before the mixture is injected.
• the aforementioned mixtures may be prepared immediately before injection by mixing two or more mixtures that are not reactive by themselves but which together yield a reacting mixture.
• the composition of the present invention presents the advantage that it initially consists of a mixture of monomers of low molecular weight that has a low viscosity. Because of this, the mixture can be injected into a mould that already contains fibrous reinforcing material, and the fibrous material will be well wetted. It is possible to inject a composition according to the invention into a mould and to let the reaction take place in an interval of between 1 s and 2 min. Preferably, the reaction is effected in 5-30 s.
• the ratio of the second component and the first component is preferably between 95 : 5 and 5 : 95 (by weight). More preferably, this ratio is between 80 : 20 and 20 : 80. The choice of ratio depends on, for example, the required composition of the reacted final product.
• the second component contains, on average. preferably at least 1.75 isocyanate groups. More preferably, the second component contains 2-3 isocyanate groups per molecule. Stil more preferably, the isocyanate functionality of the second component is on average 2.2 - 2.7.
• the polyisocyanate preferably has a molecular weight of between 100 and 400, more preferably of between 200 and 350.- Suitable polyisocyanates include aliphatic, aromatic or cycloaliphatic polyisocyanates or a combination of two or more different types.
• polyisocyanate examples include: toluene diisocyanates , 1,5-naphthalene diisocyanate, cumene- 2,4-diisocyanate, 4-methoxy-l,3-phenylene diisocyanate, 4-chloro-l,3-phenylene diisocyanate, 4-bromo-l,3-phenylene diisocyanate , 4-ethoxy-1,3-phenylene diisocyanate, 2 -4'-diisocyanatodiphenyl ether, 5,6-dimethyl-l,3-phenylene diisocyanate, 2,4-dimethyl-l,3-phenylene diisocyanate, 4,4'-diisocyanatodiphenyl ether benzidine diisocyanate, 4,6-dimethyl-13-phenylene diisocyanate, durene diisocyanate, 4,4'-diisocyanate dibenzyl, 3,3'-dimethyl-4
• the polyisocyanate is diphenyl- methane-4, '-diisocyanate (MDI) modified with carbodiimide.
• MDI diphenyl- methane-4, '-diisocyanate
• a third component may be added to the composition of the present invention. This component should be substantially hydroxy functional. This component may be, for example, a diol, polyol and/or other polyfunctional isocyanate-reactive compound. It is also possible to add an excess of polyisocyanate, although this may cause undesired effects on the properties of products manufactured from the composition.
• the third component is present in an amount of 0-30% by weight, relative to the weight of the entire composition.
• the third component should also have a molecular weight of less than 500. However, for certain applications where less strict requirements are imposed on the viscosity, it is possible to add a third component with a molecular weight of 500-3000 to a certain proportion. Examples of compounds that may be used as third component include ethylene glycol and propylene glycol.
• the number of isocyanate groups relative to the number of hydroxyl groups plus the number of amino groups in the total composition is usually at least 0.8 and at most 1.6 (mol/mol). It is possible to add a greater proportion of isocyanate groups, but this may cause the mechanical properties of objects manufactured from the composition to deteriorate.
• the composition contains catalysts.
• catalysts are less necessary for the urea reaction than for the urethane reaction.
• Suitable catalysts are all of the usual catalysts used in urethane and urea chemistry.
• Compositions according to the invention have a low viscosity and for this reason they can easily be casted or injected. It is also possible to fill the composition with fillers, fibre reinforcements and the like without causing the viscosity to increase to such an extent that the composition can no longer be processed by means of, for example, the RIM method.
• the composition may contain fibrous reinforcements for the purpose of improving the mechanical properties of the objects produced from the composition. In general, it will be possible to add 5-70 wt.% fibrous material.
• Suitable fibrous materials include glass, carbon and organic fibre materials such as aromatic polyamides. Glass fibres may be present in any suitable form, for example as a mat, a band or a ribbon, as continuous filaments or chopped staple fibres. In the case of continuous filaments they may form any structure or they may be processed in a fabric.
• the composition When the composition is used for RIM it is possible to add the fibrous reinforcement to the mixture to be injected (RRIM), provided that the fibres are short enough. It is also possible to place the fibrous structure in the mould before injection (SRIM).
• the fibrous reinforcing material may be placed loose in the mould.
• the fibrous material may be fixed or it may be inserted as a so-called preform, a fibre mat that already follows the contours of the mould in which it is to be placed.
• the composition may also contain other additives such as pigments, stabilizers, for example antioxidants and UV-stabilizers, and fillers, for example talcum, mica, calcium carbonate or carbon black.
• additives such as pigments, stabilizers, for example antioxidants and UV-stabilizers, and fillers, for example talcum, mica, calcium carbonate or carbon black.
• compositions according to the invention can be used for, for example, the production of objects according to the RIM method, in particular according to the SRIM method.
• the composition will be marketed in a two-part system (two-component system), the first part containing the first component according to the invention and the second part the polyisocyanate.
• the catalysts and/or initiators are divided between these two parts according to a method that is known to a person skilled in the art.
• the viscosity was determined with the aid of a Hake Viscometer of type HBTD with spindle 1, 100 rpm.
• the hardness was measured according to ASTM D 2240-81.
• Stress-strain properties were measured according to ASTM D412-80, including ultimate tensile strength Ts, Young's modulus E and elongation at break (e.a.b.). The test was performed on an Instron Tester (Model 4202). The sample thickness ranged from 0.13-0.135. The crosshead speed was 2 in. per min. The reported data are the average of at least 3 readings. The Young's modulus was calculated from the steepest initial slope of the chess-strain curve.
• the flexural properties were measured according to ASTM D790-81. The properties included flexural strength at yield point and flexural modulus. The test was conducted in a 3-point bending using an Instron Tester.
• the IZOD impact strength was measured according to ASTM D256, method A. Thermal properties were measured with use of a DSC thermogram (Tg) .
• the gelling point was considered reached at the moment at which the stirring bar stopped moving. Table 1 shows the results.
• the mixtures of experiments C and D also show a gelling time that is too short for them to be successfully applied on an industrial scale.
• the gelling time of the amino alcohol is suitable for application in an industrial process, for example in
• Example II The alkanolamine was prepared as follows: phthalic anhydride was melted in a reaction vessel and ethanolamine was added. The H 2 0 that resulted from the reaction was removed under vacuum. The reaction product was N-hydroxy- ethyl phthalimide (HPI). An amount of 5 mol% (relative to HPI) catalyst was added (a 30% solution of sodium methylate in methanol). The methanol was separated at 120°C under 50 mm Hg.
• HPI N-hydroxy- ethyl phthalimide
• An amount of polyoxyethylenehydroxylamine with a molecular weight of 500 was used to produce an object with the RIM technique.
• the molecule had an average of 11 ethyleneoxide units per molecule.
• a laboratory scale RIM machine RCM-800 from Hi-Tech Eng. was used.
• the amino alcohol and a chain lengthener DETDA were stored in the first vessel, while the diisocyanate Isonate 143L was stored in the second vessel.
• the first vessel was degassed under vacuum at 60-70°C for 24 h.
• the mixture was kept at a temperature of 60-75°C under 30-50 psi dry N 2 -
• the isocyanate in the second vessel was kept at room temperature under a pressure of 30-50 psi dry N 2 .
• the mixture and the isocyanate were mixed in a mixing head and injected under a pressure of 1500 psi into a closed mold, which was heated to 60-80°C at an equivalent ratio of hydroxylamine oligomer: DETDA: isocyanate of 1:1:2.1.
• the flow rate was 40 g/s.
• the shooting time was 0.7 s.
• the viscosity of the mixture was 210 cps at room temperature and 30 cps at 70°C.
• the sample was post-cured at 120°C for 1 hour.
• the process of example II was followed with a diamine instead of the aminoalcohol.
• the diamine is a polyoxyethylenediamine with a molecular weight (Mw/Mn) of 2000, from Texaco.
• Mw/Mn molecular weight of 2000
• the equivalent ratio of diamine oligomer:DETDA:isocyanate was 1:5:6.3.
• Table 2 Ph sical ro erties
• Dabco 33LV is a triethylene diamine in dipropyleneglycol from Air Products.
• UL-28 is tincarboxylate from Witco Chemicals as urethane- catalyst.
• Isonate 143L is carbondiimide modified MDI from Dow
• DETDA is diethyltoluenediamme, 80/20 mixture of 2.4- and
• Dabco T-12 is dibutyltin dilaurate from Air Products as urethanecatalyst. From Table 2 can be seen that the composition according to the present invention gives products with better mechanical properties than composition according to the state of the art: The shore D hardness, the Young's modulus E and the flexural strength and flexural modulus in Example II are all better than in Comp. Exp. E, while the Izod remains practically the same. It was not possible to use a diamine with a molecular weight below 2000, because then the resin cured much too fast.
• the process of example II was repeated with several aminoalcohols with molecular weights from 47 to 109.
• Example II The same equivalent amount of amino- and hydroxyl groups was used as in Example II.
• the results show that it is not possible to use a low molecular weight a inoalkohol for RIM: the produced samples have a foam-like structure and have bad mechanical properties.
• Example II The process of Example II was repeated with an aminoalkohol with a molecular weight of 163: polyglycolamine.
• the polyglycolamine is produced by reacting polyglycol with acrylonitrile, hydrogenating the nitrile group to an amine group and destillating the reaction mixture to obtain a hydroxylamine with a reasonable pureness.
• the resulting sample had some bubbles in it, but expressed reasonable mechanical properties. Therefore aminoalkohols with a molecular weight of 163 are considered as part of the invention, although not part of the preferred embodiment.

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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)

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Cited By (7)

Citations (4)

• 1990
  • 1990-07-06 NL NL9001544A patent/NL9001544A/nl not_active Application Discontinuation
• 1991
  • 1991-07-04 AU AU82175/91A patent/AU8217591A/en not_active Abandoned
  • 1991-07-04 WO PCT/NL1991/000116 patent/WO1992001009A1/en unknown

Patent Citations (4)

Non-Patent Citations (1)

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