WO2001032732A1 - Procede de fabrication de mousses en polyurethanne dures et souples - Google Patents

Procede de fabrication de mousses en polyurethanne dures et souples Download PDF

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WO2001032732A1
WO2001032732A1 PCT/EP2000/009730 EP0009730W WO0132732A1 WO 2001032732 A1 WO2001032732 A1 WO 2001032732A1 EP 0009730 W EP0009730 W EP 0009730W WO 0132732 A1 WO0132732 A1 WO 0132732A1
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isocyanate
polyisocyanate
foam
polyol
prepolymer
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Berend Eling
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Huntsman International LLC
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Huntsman International LLC
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/36—After-treatment
    • C08J9/38—Destruction of cell membranes
    • 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
    • C08G18/2805—Compounds having only one group containing active hydrogen
    • C08G18/2815—Monohydroxy compounds
    • C08G18/283—Compounds containing ether groups, e.g. oxyalkylated monohydroxy compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/40—High-molecular-weight compounds
    • C08G18/48—Polyethers
    • C08G18/4804—Two or more polyethers of different physical or chemical nature
    • C08G18/4808—Mixtures of two or more polyetherdiols
    • 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
    • C08G18/703—Isocyanates or isothiocyanates transformed in a latent form by physical means
    • C08G18/705—Dispersions of isocyanates or isothiocyanates in a liquid medium
    • C08G18/706—Dispersions of isocyanates or isothiocyanates in a liquid medium the liquid medium being water
    • 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
    • C08G2110/0008—Foam properties flexible
    • 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
    • C08G2110/0025—Foam properties rigid
    • 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
    • C08G2110/0083—Foam properties prepared using water as the sole blowing agent
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2205/00—Foams characterised by their properties
    • C08J2205/10—Rigid foams
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2375/00—Characterised by the use of polyureas or polyurethanes; Derivatives of such polymers
    • C08J2375/04—Polyurethanes

Definitions

  • the present invention is concerned with the use of a polyisocyanate prepolymer based on a polyalkyleneglycol monoalkylether in preparing rigid foams and flexible foams and with the foams thus obtained.
  • EP-A-0339848 discloses a process for making open-celled polyurethane foam, comprising reacting a MDI composition with a polyol component comprising:
  • a prepolymer with part only of said polyethylene glycol monoalkyl ether is foreseen in this document .
  • foams Conventional flexible polyurethane foams are widely known. Such foams show a relatively high resilience (ball rebound) , a relatively low modulus, a relatively high sag factor and a relatively low hysteresis loss. Such foams further show a major glass-rubber transition below ambient temperature, generally in the temperature range of -100°C to -10°C.
  • the commonly applied relatively high molecular weight polyether and polyester polyols in such foams are responsible for the sub-ambient glass transition temperature (Tg s ). These polyether and polyester polyols are often referred to as soft segments.
  • Tg s the foam displays its typical flexible properties until softening and/or melting of the isocyanate- derived urethane/urea clusters ("hard domains") takes place.
  • This softening and/or melting temperature (Tg h and/or Tm h ) often coincides with the onset of thermal degradation of polymer segments.
  • the Tgh and/or Tm n for flexible polyurethane foams is generally higher than 100°C, often even exceeding 200°C.
  • Tg s a sharp decrease of the modulus of the flexible foam is observed.
  • Tg s and Tgh/Tmh the modulus remains fairly constant with increasing temperature and at Tg n /Tm n again a substantial decrease of the modulus may take place.
  • Tg s A way of expressing the presence of Tg s is to determine the ratio of the Young's storage modulus E' at -100°C and +25°C as per Dynamic Mechanical Thermal Analysis (DMTA measured according to ISO/DIS 6721-5) .
  • DMTA Dynamic Mechanical Thermal Analysis
  • E '-100°C ratio is at least 25.
  • the apparent core density of such foams may range from 4-30 kg/m ⁇ and preferably ranges from 4-20 kg/m3 (measured according to ISO/DIS845) .
  • Such foams are made by crushing a rigid foam.
  • the present invention provides such a formulation and process. Without wishing to be bound to any theory, it is believed that when the polyol blend (which in itself is an emulsion) , is brought into contact with the isocyanate, the water-rich phase is emulsified into the isocyanate.
  • the isocyanate of the invention facilitates the formation, and once formed, stabilizes the formed emulsion, providing an intimate contact between water and isocyanate.
  • Other advantages are also obtained, which are significant increase of the robustness of the foaming system and an improved crushability of the rigid foams.
  • the isocyanates of the invention have a reduced NCO value, which results in lower reaction exotherms. The risk of scorch is thus reduced.
  • a flexible polyurethane foam is a crushed foam having a ball rebound (measured according to ISO 8307) of at least 40%, preferably at least 50% and most preferably 55-85% in at least one of the three dimensional directions and a sag factor (CLD 65/25) of at least 2.0 (measured according to ISO 3386/1).
  • a sag factor CLD 65/25) of at least 2.0 (measured according to ISO 3386/1).
  • such flexible foams have a Young's storage modulus at 25°C of at most 500 kPa, more preferably at most 350 kPa and most preferably between 10 and 200 kPa (Young's storage modulus measured by DMTA according to ISO/DIS 6721-5) .
  • such flexible foams preferably have a sag factor (CLD 65/25) of at least 3.5 and most preferably 4.5-10 (measured according to ISO 3386/1). Still further such flexible foams preferably have a CLD hysteresis loss (ISO 3386/1) of below 55%, more preferably below 50% and most preferably below 45%.
  • a rigid polyurethane foam is an uncrushed foam having a ball rebound measured in the direction of foam rise of less than 40% (ISO 8307 with the proviso that no preflex conditioning is applied, that only one rebound value per sample is measured and that test pieces are conditioned at 23°C ⁇ 2°C and 50 ⁇ 5% relative humidity) and/or having a CLD 65/25 sag factor measured in the direction of foam rise of less than 2.0 (ISO 3386/1 with the proviso that the sag factor is determined after the first load - unload cycle) ; these properties both being measured at a core density of the foam of 3-27 kg/m 3 (ISO 845).
  • the ratio E'_ ]_00°c/ E '+25°C of such a rigid foam is 1.3-15. If in the present application ISO 8307 and ISO 3386/1 are mentioned in relation to rigid foams they refer to the tests as described above including the provisos.
  • isocyanate index or NCO index or index the ratio of NCO-groups over isocyanate-reactive hydrogen atoms present in a formulation, given as a percentage:
  • the NCO-index expresses the percentage of isocyanate actually used in a formulation with respect to the amount of isocyanate theoretically required for reacting with the amount of isocyanate-reactive hydrogen used in a formulation.
  • the isocyanate index as used herein is considered from the point of view of the actual foaming process involving the isocyanate ingredient and the isocyanate-reactive ingredients.
  • Any isocyanate groups consumed in a preliminary step to produce modified polyisocyanates (including such isocyanate-derivatives referred to in the art as quasi or semi-prepolymers and prepolymers) or any active hydrogens consumed in a preliminary step (e.g. reacted with isocyanate to produce modified polyols or polyamines) are not taken into account in the calculation of the isocyanate index. Only the free isocyanate groups and the free isocyanate-reactive hydrogens (including those of the water) present at the actual foaming stage are taken into account.
  • isocyanate-reactive hydrogen atoms refers to the total of active hydrogen atoms in hydroxyl and amine groups present in the reactive compositions; this means that for the purpose of calculating the isocyanate index at the actual foaming process one hydroxyl group is considered to comprise one reactive hydrogen, one primary amine group is considered to comprise one reactive hydrogen and one water molecule is considered to comprise two active hydrogens.
  • Reaction system a combination of components wherein the polyisocyanates are kept in one or more containers separate from the isocyanate-reactive components.
  • polyurethane foam refers to cellular products as obtained by reacting polyisocyanates with isocyanate-reactive hydrogen containing compounds, using foaming agents, and in particular includes cellular products obtained with water as reactive foaming agent (involving a reaction of water with isocyanate groups yielding urea linkages and carbon dioxide and producing polyurea-urethane foams) and with polyols, aminoalcohols and/or polyamines as isocyanate-reactive compounds.
  • average nominal hydroxyl functionality is used herein to indicate the number average functionality (number of hydroxyl groups per molecule) of the polyol or polyol composition on the assumption that this is the number average functionality (number of active hydrogen atoms per molecule) of the initiator (s) used in their preparation although in practice it will often be somewhat less because of some terminal unsaturation.
  • average refers to number average unless indicated otherwise.
  • the foams according to the present invention are prepared by reacting a polyisocyanate (1), an isocyanate-reactive compound (2), said compound (2) having an average equivalent weight of at most 374 and an average number of isocyanate- reactive hydrogen atoms of from 2 to 8, an isocyanate- reactive compound (3), said compound (3) having an average equivalent weight of more than 374 and an average number of isocyanate-reactive hydrogen atoms of from 2 to 6 and water in the presence of a catalyst to prepare a rigid polyurethane foam and by crushing this rigid polyurethane foam to prepare a flexible polyurethane foam, where the polyisocyanate comprises a prepolymer which is the reaction product of polyisocyanate and a polyalkyleneglycol monoalkylether.
  • reaction product covers notably those embodiments where the molar ratio NCO:OH is from 99:1 to 75:25.
  • reaction product covers notably the embodiment where the amount of polyalkyleneglycol monoalkylether represents from 5 to 20% by weight of the weight of the final prepolymer .
  • Said polyalkyleneglycol monoalkylether is of the formula R-A- OH, where R is an alkyl group containing 1 to 20, preferably 1 to 6 carbon atoms and A is a polyalkyleneoxy chain having a total chain length of 2 to 40 units.
  • Preferred polyalkyleneglycol monoalkylethers are mono (C_-C4alkyl) ethers of polyethyleneglycol.
  • the polyalkyleneoxy chain preferably consists of ethyleneoxy and/or propyleneoxy units, most preferably of ethyleneoxy units.
  • the molecular weight of the polyalkyleneglycol monoalkylether is preferably between 100 and 1000.
  • said polyalkylene glycol monoalkyl ether is completely reacted in the prepolymer.
  • the polyol (s) composition reacting with the isocyanate (the prepolymer thereof) is free of said polyalkylene glycol monoalkyl ether.
  • the amount of polyalkylene glycol monoalkyl ether is less than four times the amount of water used in the process of the invention.
  • the isocyanate used in making the prepolymer is preferably polymeric MDI (or variants thereof as defined below) , the polymeric MDI having an average functionality 2.3 to 2.9, and preferably 2.5 to 2.7.
  • the (polymeric) MDI prepolymer has an NCO value preferably between 15 and 29%, most preferably between 20 and 29%.
  • the polyisocyanate used in the invention comprises the polyalkyleneglycol monoalkylether containing prepolymer in varying amounts. While it can be comprised of solely the prepolymer, it may also comprise limited amounts of polyalkyleneglycol monoalkylether containing prepolymer. For example, the polyisocyanate can comprise from 100 to 20% by weight of the polyalkyleneglycol monoalkylether containing prepolymer.
  • Suitable organic polyisocyanates for use in the process of the present invention include any of those known in the art for the preparation of rigid polyurethane foams, like aliphatic, cycloaliphatic, araliphatic and, preferably, aromatic polyisocyanates, such as toluene diisocyanate in the form of its 2,4 and 2,6-isomers and mixtures thereof and diphenylmethane diisocyanate in the form of its 2,4'-, 2,2'- and 4,4'-isomers and mixtures thereof, the mixtures of diphenylmethane diisocyanates (MDI) and oligomers thereof having an isocyanate functionality greater than 2 known in the art as "crude” or polymeric MDI (polymethylene polyphenylene polyisocyanates), the known variants of MDI comprising urethane, allophanate, urea, biuret, carbodiimide, uretonimine and/or isocyanurate groups.
  • toluene diisocyanate and diphenylmethane diisocyanate and/or polymethylene polyphenylene polyisocyanates may be used. Most preferably polyisocyanates are used which have an average isocyanate functionality of 2.1-3.0 and preferably of 2.2-2.8.
  • MDI, crude or polymeric MDI and/or liquid variants thereof are used said variants being obtained by introducing uretonimine and/or carbodiimide groups into said polyisocyanates, such a carbodiimide and/or uretonimine modified polyisocyanate having an NCO value of at least 20% by weight, and/or by reacting such a polyisocyanate with one or more polyols having a hydroxyl functionality of 2-6 and a molecular weight of 62-500 so as to obtain a modified polyisocyanate having an NCO value of at least 20% by weight.
  • the isocyanate blended with the prepolymer is preferably polymeric MDI, a mixture of 2,4' and 4,4' MDI or a prepolymer of a mixture of 2,4' and 4,4' MDI.
  • the ratio of 2,4' and 4,4' MDI amounts preferably from 0/100 to 70/30.
  • the isocyanate or isocyanate prepolymer used in the blending may contain uretonimine and/or carbodiimide groups.
  • the polyol used in the manufacturing of the prepolymer based on the mixture of 2,4' and 4,4' MDI has a functionality 2 to 8, preferably 2 to 3, and a molecular weight from 62 to 8000.
  • An example of such a prepolymer is an isocyanate reacted with diols with molecular weight between 62 and 250.
  • Such prepolymers have an NCO value between 20 and 30%.
  • Another example is a prepolymer reacted with a diol or a triol, or a mixture of a diol and a triol, with hydroxyl values between 21 and 100 mgKOH/g.
  • Such prepolymers typically have an NCO value between 6 and 25%.
  • the NCO value of the isocyanate used in blending with the polyalkyleneglycol monoalkylether containing prepolymer amounts typically to 20 to 33.6%.
  • the NCO value of the polyisocyanate containing the polyalkyleneglycol monoalkylether prepolymer to produce the rigid foam is typically from 16 to 32%, more preferably between 20 and 30% and most preferably between 25 and 30%.
  • Prepolymerisation of the isocyanate used in blending is also preferred according to one embodiment (it is believed this also improves system miscibility) .
  • the foams according to the present invention are prepared by reacting the above polyisocyanate (1), a polyol (2) having a hydroxyl number of at least 150 mg KOH/g and an average nominal hydroxyl functionality of from 2 to 8, a polyol (3) having a hydroxyl number of from 10 to less than 150mg KOH/g and an average nominal hydroxyl functionality of from 2 to 6 and water in the presence of a catalyst to prepare a rigid polyurethane foam and by crushing this rigid polyurethane foam to prepare a flexible polyurethane foam.
  • Isocyanate-reactive compounds (2) include any of those known in the art for that purpose like polyamines, aminoalcohols and polyols. Of particular importance for the preparation of the rigid foams are polyols and polyol mixtures having hydroxyl numbers of at least 150 mg KOH/g and an average nominal hydroxyl functionality of from 2 to 6. Suitable polyols have been fully described in the prior art and include reaction products of alkylene oxides, for example ethylene oxide and/or propylene oxide, with initiators containing from 2 to 8 active hydrogen atoms per molecule.
  • Suitable initiators include : polyols, for example ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butane diol, glycerol, trimethylolpropane, triethanolamine, pentaerythritol, sorbitol and sucrose; polyamines, for example ethylene diamine, tolylene diamine, diaminodiphenylmethane and polymethylene polyphenylene polyamines; and aminoalcohols, for example ethanolamine and diethanolamine; and mixtures of such initiators.
  • Other suitable polyols include polyesters obtained by the condensation of appropriate proportions of glycols and higher functionality polyols with polycarboxylic acids.
  • Still further suitable polyols include hydroxyl terminated polythioethers, polyamides, polyesteramides, polycarbonates, polyacetals, polyolefins and polysiloxanes .
  • Still further suitable isocyanate-reactive compounds include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butane diol, glycerol, trimethylolpropane, ethylene diamine, ethanolamine, diethanolamine, triethanolamine and the other initiators mentioned before. Mixtures of such isocyanate-reactive compounds may be used as well. Most preferably polyols are used which do not comprise primary, secondary or tertiary nitrogen atoms.
  • Isocyanate-reactive compounds (3) include any of those known in the art for that purpose, like polyamines, aminoalcohols and polyols. Of particular importance for the preparation of the rigid foams are polyols and polyol mixtures having a hydroxyl value of 10 to less than 150 and preferably of 15-60 mg KOH/g and an average nominal hydroxyl functionality of from 2 to 6 and preferably of from 2 to 4. These high molecular weight polyols are generally known in the art and include reaction products of alkylene oxides, for example ethylene oxide and/or propylene oxide, with initiators containing from 2 to 6 active hydrogen atoms per molecule.
  • Suitable initiators include : polyols, for example ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butane diol, glycerol, trimethylolpropane, triethanolamine, pentaerythritol and sorbitol; polyamines, for example ethylene diamine, tolylene diamine, diaminodiphenylmethane and polymethylene polyphenylene polyamines; and aminoalcohols, for example ethanolamine and diethanolamine; and mixtures of such initiators.
  • Other suitable polyols include polyesters obtained by the condensation of appropriate proportions of glycols and higher functionality polyols with polycarboxylic acids.
  • polystyrene resins include hydroxyl terminatedpolythioethers, polyamides, polyesteramides, polycarbonates, polyacetals, polyolefins and polysiloxanes .
  • Preferred polyols are the polyether polyols comprising ethylene oxide and/or propylene oxide units and most preferably polyoxyethylene polyoxypropylene polyols having an oxyethylene content of at least 10% and preferably 10-85% by weight.
  • Other polyols which may be used comprise dispersions or solutions of addition or condensation polymers in polyols of the types described above.
  • modified polyols often referred to as "polymer” polyols have been fully described in the prior art and include products obtained by the in situ polymerisation of one or more vinyl monomers, for example styrene and acrylonitrile, in polymeric polyols, for example polyether polyols, or by the in situ reaction between a polyisocyanate and an amino- or hydroxy-functional compound, such as triethanolamine, in a polymeric polyol.
  • vinyl monomers for example styrene and acrylonitrile
  • polymeric polyols for example polyether polyols
  • polyether polyols for example polyether polyols
  • an amino- or hydroxy-functional compound such as triethanolamine
  • the polymer modified polyols which are particularly interesting in accordance with the invention are products obtained by in situ polymerisation of styrene and/or acrylonitrile in polyoxyethylene polyoxypropylene polyols and products obtained by in situ reaction between a polyisocyanate and an a ino or hydroxy-functional compound (such as triethanolamine) in a polyoxyethylene polyoxypropylene polyol.
  • a polyisocyanate an a ino or hydroxy-functional compound (such as triethanolamine) in a polyoxyethylene polyoxypropylene polyol.
  • Polyoxyalkylene polyols containing from 5 to 50% of dispersed polymer are particularly useful. Particle sizes of the dispersed polymer of less than 50 microns are preferred. Mixtures of such isocyanate-reactive compounds may be used as well.
  • Most preferably polyols are used which do not comprise primary, secondary or tertiary nitrogen atoms.
  • the relative amount of isocyanate-reactive compound (2) and (3) or polyol (2) and (3) may vary widely and preferably ranges from 0.1:1 to 4:1 (w:w).
  • the relative quantities of the polyisocyanate and the isocyanate-reactive compounds to be reacted may vary within a wide range.
  • an isocyanate index will be applied of from 25 to 300, preferably of from 30 to 200, preferably 91 to 200 and most preferably of from 102 to 150.
  • any other known way to prepare polyurethane foams may be employed additionally, like the use of reduced or variable pressure, the use of a gas like air, N2 and CO2 , the use of more conventional blowing agents like chlorofluorocarbons, hydrofluorocarbons, hydrocarbons and fluorocarbons, the use of other reactive blowing agents, i.e.
  • blowing agent may vary widely and primarily depends on the desired density. Water may be used as liquid at below- ambient, ambient or elevated temperature and as steam.
  • One combination of blowing agent is water and CO2 wherein the CO2 is added to the ingredients for making the foam in the mixing head of a device for making the foam, to one of the isocyanate-reactive ingredients and preferably to the polyisocyanate before the polyisocyanate is brought into contact with the isocyanate-reactive ingredients.
  • polyisocyanate (1) isocyanate- reactive compound (2) and compound (3) or polyol (2) and polyol (3) and water
  • amount of compound (2) or polyol (2) ranges from 2-20 parts by weight
  • amount of compound (3) or polyol (3) ranges from 5-35 parts by weight
  • amount of water ranges from 1 to 17 parts by weight, the remainder being polyisocyanate.
  • these amounts are 55-80, 3-20, 10-30 and 2-6 parts by weight for the polyisocyanate, polyol (2), polyol (3) and water respectively.
  • a cyclic polyisocyanate and more in particular an aromatic polyisocyanate and most in particular an MDI or polymethylenepolyphenylene polyisocyanate is used the content of cyclic and more in particular of aromatic residues in the flexible foam is relatively high as compared to conventional flexible polyurethane foams.
  • the foams according to the invention preferably have a content of benzene rings, derived from aromatic polyisocyanates, which is 30 to 56 and most preferably 35 to 50% by weight based on the weight of the foam.
  • the overall benzene ring content of the flexible foam may be higher and preferably ranges from 30 to 70 and most preferably from 35 to 65% weight as measured by calibrated Fourier Transform Infra Red Analysis.
  • the present invention is more in particular concerned with a process for preparing rigid polyurethane foams by reacting the above polyisocyanate (1), a polyether polyol (2) having a hydroxyl number of at least 150 mg KOH/g and an average nominal hydroxyl functionality of from 2 to 8, a polyether polyol (3) having a hydroxyl number of from 10 to less than 150 mg KOH/g and an average nominal hydroxyl functionality of from 2 to 6 and water, wherein the amount of polyisocyanate (1), polyol (2), polyol (3) and water is 55-80, 3-20, 10-30 and 2-6 parts by weight respectively per 100 parts by weight of polyisocyanate (1), polyol (2), polyol (3) and water, in the presence of a catalyst and wherein the reaction is conducted at an isocyanate index of 70-200 and wherein the polyisocyanate is reacted with one or more isocyanate- reactive compositions comprising one or more of the aforementioned polyol (2), polyol (3) and water.
  • This preferred process gives foams with reduced thermal degradation, especially when such foams are made as large buns e.g. on a moving conveyor belt (slab-stock foam), the foams have improved stability and a low amount of extractables .
  • An even further preferred process is a process for preparing a rigid foam by reacting a polyisocyanate (1), a polyether polyol (2) having an average equivalent weight of 70-300 and preferably of 70-200, having an average nominal hydroxyl functionality of from 2 to 6 and preferably from 2 to 3 and an oxyethylene content of at least 75% by weight, a polyether polyol (3) having an average equivalent weight of 1000-3000, having an average nominal hydroxyl functionality of 2 to 3 and preferably of 2 and having the structure
  • EO is an ethylene oxide radical
  • PO is a propylene oxide radical
  • x l-15 and preferably 3-10
  • y 0-6 and preferably 1-4
  • z is such so as to arrive at the above equivalent weight
  • n 1-2
  • X is a hydrocarbon radical having 2-10 and preferably 2-6 carbon atoms or a radical having the formula -CH2-CH2- (OCH2-CH2) -2 ⁇ > and water in the presence of a catalyst wherein the amount of polyisocyanate
  • (1), polyol (2), polyol (3) and water is 55-80, 3-20, 10-30 and 2-6 parts by weight respectively per 100 parts by weight of polyisocyanate (1), polyol (2), polyol (3) and water and wherein the reaction is conducted at an isocyanate index of 70-200, preferably 102-200, most preferably 102-150 and wherein the polyisocyanate is reacted with one or more isocyanate-reactive compositions comprising one or more of the aforementioned polyol (2), polyol (3) and water.
  • the amount of water is 3-5 parts by weight calculated on the same basis as above.
  • the weight ratio of water and polyol (3) is 0.1 to 0.4:1 and the weight ratio of polyol (3) and of polyol (2) + water is 0.9-2.5:1
  • polyether polyols (3) are those according to formula 1, described hereinbefore. Those having a nominal hydroxyl functionality of 3 may be prepared by ethoxylation of an initiator, followed by propoxylation and again ethoxylation, wherein the initiator is a triol like glycerol and/or trimethylol propane.
  • Those having a nominal hydroxyl functionality of 2 may be prepared by ethoxylation of ethylene glycol, diethylene glycol and/ortriethylene glycol, followed by propoxylation and again ethoxylation; or by propoxylation of ethylene glycol, diethylene glycol and/or triethylene glycol followed by ethoxylation; or by propoxylation of a polyoxyethylene polyol having 4-15 oxyethylene groups followed by ethoxylation. Mixtures of such most preferred polyols may be used as well. Although not necessary other polyols may be used together with these most preferred polyols according to formula 1, provided the amount does not exceed 30% by weight based on the weight of these polyols according to formula 1. Such polyols according to formula 1 are commercially available (e.g. Daltocel F430 from HUNTSMAN) .
  • catalysts may be used which enhance the formation of urethane and urea bonds like amines, such as triethylene diamine, tin compounds, such as dibutyltin dilaurate and stannous octoate, and/or phosphates like NaH2P ⁇ 4 and Na2HP0 _ Amine catalysts may be used; according to one embodiment they are not used, with the exception of ethylene- diaminetetraacetic acid (EDTA) , ethylenebis- (oxyethylene- nitrilo) tetraacetic acid (EGTA) .
  • EDTA ethylene- diaminetetraacetic acid
  • EGTA ethylenebis- (oxyethylene- nitrilo) tetraacetic acid
  • HEDTA (2-hydroxyethyl) - ethylenediaminetriacetic acid
  • DHPTA 1, 3-diamino-2- hydroxypropane-N,N,N' ,N ' -tetraacetic acid
  • a tin salt of a carboxylic acid having 2-18 carbon atoms (hereinafter called “catalyst 1"), together with a lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium and/or barium salt of a protic acid, the acid having at least 2 acidic hydrogen atoms and having a pK a in water of 2-10 (hereinafter called “catalyst 2”), in a ratio of catalyst 1: catalyst 2 of 30:70 to 95:5 and in an amount of catalyst 1 and catalyst 2 of each 0.1-5% by weight (calculated on the weight of all ingredients used to prepare the foam) .
  • Catalyst 1 tin salt of a carboxylic acid having 2-18 carbon atoms
  • catalyst 2 a lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium and/or barium salt of a protic acid
  • the acid having at least 2 acidic hydrogen atoms and having a pK
  • the amount of catalyst preferably varies from 0.2 to 3% by weight calculated on the weight of all ingredients used to prepare the polyurethane foam.
  • Catalysts are preferably mixed with the isocyanate-reactive compounds before the foaming reaction takes place. More preferably catalyst 1 is mixed with a part of the isocyanate-reactive compounds and catalyst 2 is mixed with another part of the isocyanate-reactive compounds; subsequently these mixtures are fed to a mixing head of a foaming device where they are mixed with the polyisocyanate.
  • auxiliaries or additives known per se for the production of polyurethane foams may be used.
  • auxiliaries or additives include foam-stabilizing agents or surfactants, for example siloxane-oxyalkylene copolymers and polyoxyethylene polyoxypropylene block copolymers, anti-oxidants, anti-static agents, UV stabilisers, anti-microbial and anti-fungal compounds and fillers like latex, TPU, silicates, barium and calcium sulphates, chalk, glass fibers or beads and polyurethane waste material.
  • foam-stabilizing agents or surfactants for example siloxane-oxyalkylene copolymers and polyoxyethylene polyoxypropylene block copolymers, anti-oxidants, anti-static agents, UV stabilisers, anti-microbial and anti-fungal compounds and fillers like latex, TPU, silicates, barium and calcium sulphates, chalk, glass fibers or beads and polyurethane waste material.
  • additives and auxiliaries are used which do not comprise primary
  • the known one-shot, prepolymer or semi- prepolymer techniques may be used together with conventional mixing methods and the rigid foam may be produced in the form of slabstock, mouldings including foam in fabric and pour-in- place applications, sprayed foam, frothed foam or laminates with other materials such as hardboard, plasterboard, plastics, paper or metal or with other foam layers.
  • an isocyanate- reactive composition may be used which contains the catalysts and the auxiliaries, additives and the blowing agent in addition to the isocyanate-reactive compounds (2) and (3) in the form of a solution, an emulsion or dispersion.
  • the isocyanate-reactive components may also be supplied independently to the polyisocyanate as two or more compositions containing the catalysts and the additives and auxiliaries .
  • the rigid foam is prepared by allowing the aforementioned ingredients to react and foam until the foam does not rise any more. After rise curing of the foam may be continued as long as desirable. In general a curing period of 1 minute to 24 hours and preferably of 5 minutes to 12 hours will be sufficient. If desired curing may be conducted at elevated temperature. Subsequently the foam may be crushed. It is however preferred to allow the rigid foam obtained to cool down to below 80°C, preferably below 50°C and most preferably to ambient temperature prior to crushing.
  • the rigid foam i.e. before crushing
  • the rigid foam preferably has a core density of 3-35 and more preferably of 8-25 kg/m 3 (ISO 845) .
  • the rigid foam (i.e. before crushing) prepared has a substantial amount of open cells.
  • the cells of the rigid foam are predominantly open.
  • the crushing may be conducted in any known manner and by any known means .
  • the crushing may for instance be conducted by applying mechanical force onto the foam by means of a flat or pre-shaped surface or by applying variations of external pressure .
  • a mechanical force sufficient to decrease the dimension of the foam in the direction of the crushing by 1- 90%, preferably by 50-90% will be appropriate.
  • crushing may be repeated and/or carried out in different directions of the foam. Due to the crushing the ball rebound increases considerably in the direction of the crushing. Due to the crushing the density of the foam may increase. In most cases this increase will not exceed 30% of the density before crushing.
  • the foam may be crushed in the direction of foam rise.
  • a special foam is obtained when the crushing is conducted in a direction perpendicular to the direction of foam rise : then a foam is obtained with a highly anisotropic cell structure.
  • the core density of the flexible foam is 3-30 and preferably 3-20 kg/m 3 .
  • the foam may be subjected to a heat treatment in order to reduce the density increase caused by the crushing.
  • This heat treatment is conducted at 70-200°C and preferably at 90-180°C for 0.5 minute to 8 hours and preferably for 1 minute to 4 hours.
  • the oxygen index of the foam prepared from aromatic polyisocyanates preferably is above 20 (ASTM 2863) . Further it shows a Young's storage modulus at 25°C of at most 500 kPa, preferably at most 350 kPa, most preferably between 10- 200 kPa and a sag factor (CLD 65/25, ISO 3386/1) of at least 2.0, preferably at least 3.5 and most preferably of 4.5-10.
  • CLD hysteresis loss values for the foams are below 55% and preferably below 50% (which is calculated by the formula
  • a and B stand for the area under the stress/strain curve of the loading (A) and unloading (B) as measured according to ISO 3386/1) . Still further these foams can be manufactured with a very low or even negative Poisson's ratio as determined by lateral extension studies under compression of the foams. Finally compression set values of the foams are generally low, preferably below 40% (ISO 1856 Method A, normal procedure) .
  • the foam might be used in thermoforming processes to prepare shaped articles.
  • the Tg h of the foam is between 80 and 180°C, most preferably between 80°C and 160°C for such thermoforming applications.
  • foams which have been made by using a relatively low amount of the polyols having a low molecular weight, show a small or non-visible Tg n by DMTA (the modulus change at Tg h is small or the modulus changes gradually until the foam thermally decomposes); such foams may be used for thermoforming activities as well.
  • the foams of the present invention may be used as cushioning material in furniture and automotive and aircraft seating and in mattresses, as carpet backing, as hydrophilic foam in diapers, as packaging foam, as foams for sound insulation in automotive applications and for vibration isolation in general.
  • the foam according to the present invention further may be used together with other, conventional flexible foams to form composites, like e.g. in mouldings; such composites may also be made by allowing the ingredients for making the conventional flexible foam to form said foam in a mould in the presence of the foam according to the present invention or alternatively by allowing the ingredients for making the rigid foam according to the present invention to form said rigid foam in a mould in the presence of the conventional flexible foam followed by crushing the moulding so obtained.
  • foams according to the present invention may be used as textile cover, as cover for other type of sheets, as carpet underlay or felt-replacement; the so-called flame lamination technique may be applied to adhere the foam to the textile, the carpet or the other sheet.
  • the foam according to the present invention is suitable to be cut in sheets of limited thickness, e.g. of about 1 cm and less.
  • the foam according to the present invention may be used as insulation material around pipes and containers.
  • the instant foam may contain those flame retardants disclosed in patent application W09931173, the content of which is incorporated herein by reference. This application discloses certain flame retardants comprising polybrominated diphenylethers and/or dialkyl esters of polybrominated phthalic acid and/or phosphorous compounds.
  • the instant foam may also contain flame retardants known in the art, such as melamine and/or guanidine carbonate, as well as others such as a mixture of expandable graphite and phosphorous compounds of the formula P(0)XYZ, wherein X,Y and Z are independently selected from the groups -R and -OR' wherein R is an alkyl, aryl or aralkyl group having 1-12 and preferably 1-10 carbon atoms, and R' is an aryl or aralkyl group having 6-12 and preferably 6-10 carbon atoms.
  • the expandable graphite is already known in the art.
  • the phosphorous-containing compounds include triphenylphosphine oxide, triphenylphosphate, triphenylphosphonate and compounds having one or more, and preferably one, alkyl group (s) having 1-6 carbon atoms, attached to one or more of the aromatic rings of these triphenylphosphate, - phosphonate and - phosphine oxide, such as the commercially available Reofos 50 and Kronitex CDP both obtainable from FMC Corporation, which have on average one isopropyl and one methyl group per triphenyl phosphate molecule respectively.
  • the relative amount of the compounds in such mixtures is such that the weight ratio of phosphorous- containing compound to expandable graphite is from about 1/9 to about 4/1.
  • the amount of fire retardants used to prepare the foam is preferably such that the combined weight of phosphorous- containing compound and expandable graphite is 5-30%, most preferably 6-20%, by weight calculated on the total formulation (polyisocyanate, polyols, water, catalyst, additives, auxiliaries and fire retardants).
  • the fire retardants may be fed to the mixing head of the device to make the foam separately or after having been mixed.
  • the foams of the invention show improved physical properties of the foams; in particular tensile strength and tear strength are improved.
  • NCO value is 30.9%.
  • Isocyanate C MDI comprising 30% of 2,4'- and 2,2'.
  • NCO value is 33.6%.
  • Isocyanate D Prepolymer obtained by reacting 9 parts by weight of Isocyanate A with 1 part of a polyethyleneglycol monomethylether having a MW of 500. Final NCO value is 26.8%
  • Isocyanate D is obtained in the following manner.
  • Isocyanate 900g of isocyanate A and lOOg of the polyethyleneglycol monomethylether are mixed in a jar for 2 minutes. The jar is closed and put in an oven at 70°C for 6 hours, and allowed to cool to room temperature.
  • Blend A comprises 200 parts by weight polyol A, 3.6 pbw DabcoT9, 5.6 pbw Irganoxll35 and 0.22 pbw Irgafos TNPP.
  • Blend B comprises 40 pbw water and 2.0 pbw EDTA3Na.
  • Blend C is comprised of polyol B.
  • Blend D is comprised of the isocyanate (s) . These blends are mixed for 13 seconds at room temperature and poured in a 50cmx50cmx50cm wooden mould, the inner walls of which being covered with paper. One hour after the foam had stopped rising, the foam was taken out from the mould and allowed to cool to ambient temperature. A rigid foam is obtained. The core is crushed by one compression
  • the properties of the foam are determined according to the following methods and standards : Compression hardness CLD 25, 40 and 65% (kPa) ISO 3386-1

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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)
  • Life Sciences & Earth Sciences (AREA)
  • Cell Biology (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Dispersion Chemistry (AREA)
  • Polyurethanes Or Polyureas (AREA)

Abstract

L'invention concerne un procédé de préparation de mousses en polyuréthanne dures et souples par réaction d'un polyisocyanate, de polyols et de l'eau en présence d'un catalyseur. Le polyisocyanate contient un prépolymère qui est le produit de réaction d'un polyisocyanate et d'un polyalkylène glycol monoalkyléther.
PCT/EP2000/009730 1999-11-02 2000-10-05 Procede de fabrication de mousses en polyurethanne dures et souples Ceased WO2001032732A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU79142/00A AU7914200A (en) 1999-11-02 2000-10-05 Process for making rigid and flexible polyurethane foams

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP99121696.1 1999-11-02
EP99121696 1999-11-02

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Publication Number Publication Date
WO2001032732A1 true WO2001032732A1 (fr) 2001-05-10

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0339848A1 (fr) * 1988-04-25 1989-11-02 Imperial Chemical Industries Plc Procédé de préparation de mousses de polyuréthane
US5424386A (en) * 1992-04-08 1995-06-13 Bayer Aktiengesellschaft Modified aromatic polyisocyanates and their use for the production of rigid foamed materials
US5900442A (en) * 1995-05-12 1999-05-04 Imperial Chemical Industries Plc Flexible polyurethane foams

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0339848A1 (fr) * 1988-04-25 1989-11-02 Imperial Chemical Industries Plc Procédé de préparation de mousses de polyuréthane
US5424386A (en) * 1992-04-08 1995-06-13 Bayer Aktiengesellschaft Modified aromatic polyisocyanates and their use for the production of rigid foamed materials
US5900442A (en) * 1995-05-12 1999-05-04 Imperial Chemical Industries Plc Flexible polyurethane foams

Also Published As

Publication number Publication date
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