NZ185278A - Polyurethane foam with reduced amount of residual aromatic amine process therefor - Google Patents

Description

New Zealand Paient Spedficaiion for Paient Number 1 85278 185278 AMENDED under Section ... of Che Patents Act 1953 fromJxL&dCLz24£i ASSISTWT COMMISSIONER OF PATENTS Priority D«itel«V. -J- J & // — Compt^' ice^r Vo" ClBM Publication P.O. Joumai, hte t 9- O :"-'A 28 APRfQlI AMENDED under Section of the Patents Act 1953 fxc/m ASSISTANT COMMISSIONER OF PATENTS NEW ZEALAND A/28060 PATENTS ACT 1953 PATENTS FORM NO. 5 COMPLETE SPECIFICATION "POLYURETHANE FOAMS" WE, W.R. GRACE & CO., a Corporation organized and existing under the laws of the State of Connecticut, United States of America, of Grace Plaza, 1114 Avenue of the Americas, New York, New York. 10036, United States of America, hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement: - i - 1 852 7 NOW AMENDSgJ THIS INVENTION relates^/o polyurethane foam production. Polyurethane foams are' now quite ybommonly employed for use in surgery and other application^ involving contact with the body. Generally such fdams have some hydrophilic character by the inclusion of a separate hydropt/ilic additive into a hydrophobic polyisocyanaj/e either du/ing or after foaming.

Such foams have also be^n prepared /by reacting polyoxyethylene polyols with a polyiscfcyanate and/low, i.e., near stoichiometric / 7 amounts of water. At catalyst is' generally employed in such reactions. Foams based on non/catalytic reactions have also / been prepared using linear po/lyoxyethylene diols, dusocyanate / i; y and varying amounts of water. Hydrophilic cross-linked / / polyurethane foams may be prepared simply by reacting an / / isocyanate capped polyoxyethylene polyol with large amounts 15 of water gr&atly in exce'ss of the stoichiometric amounts needed for curing. These fo^rns generally contain residual by-products which are loosely boynd into the foam and which easily extract during/use. / / It has been discovered that polyurethane foams contain residual aromatic/^ amines which are believed to result from / / hydrolysis of i/socyanates during and subsequent to the foaming process, and possibly due to hydrolysis of the foam during storage. Fdr example, both one-shot and prepolymer foams employing .toluene diisocyanate have been found to contain the corresponding amine, namely toluene diamine (TDA). It is / ... believed that foams employing other aromatic polyisocyanates I . ' 1 852.78 f.J:* ,/v • ;.v -. ',0 THIS INVENTION relates to polyurethane foam production.

Polyurethane foams are now quite commonly employed for use in surgery and other applications involving contact with the body. Generally such foams have some hydrophilic character by the inclusion of a separate hydrophilic additive into a hydrophobic polyisocyanate either during or after foaming.

Such foams have also been prepared by reacting polyoxyethylene polyols with a polyisocyanate and low, i.e., near stoichiometric amounts of water. A catalyst is generally employed in such reactions. Foams based on non-catalytic reactions have also been prepared using linear polyoxyethylene diols, diisocyanate and varying amounts of water. Hydrophilic cross-linked polyurethane foams may be prepared simply by reacting an isocyanate capped polyoxyethylene polyol with large amounts of water greatly in excess of the stoichiometric amounts needed for curing. These foams generally contain residual by-products which are loosely bound into the foam and which easily extract during use.

It has been discovered that polyurethane foams contain residual aromatic amines which are believed to result from hydrolysis of isocyanates during and subsequent to the foaming process, and possibly due to hydrolysis of the foam during storage. For example prepolymer foams employing toluene diisocyanate have been found to contain the corresponding amine, namely toluene diamine (TDA). It is believed that foams employing other aromatic polyisocyanates 185278 / Arp H-S-Sv mm contain the corresponding pol^amine. Thfe term "aromatic limine" as used herein is_ intended to refer primarily to TDA but it also includes other aromatic amines formed 'from the corresponding poly- isocyanates. According to/the present invention the amount of aromatic amine is reduced,/by introducing a "scavenger", generally prior to foaming, said Scavenger b^ing a material which can survive the foaming reaction, t j react wit|4 aromatic amines as they are generated. Accordingly the present invention provides a process for preparing a fluid-permeable (as/hereinafter defined) polyurethane foam derived from a/n aromatic poly-isocyanate which comprises inc- K A iwvpiaO- er iSotyAiAafe-j orporating a scavenger for aromatic amineAeither in: (a) a mixture of an aromatic poly-isocyanate, a polyether or polyester polyol and water in which case the index of said scavenger in the mixture i's from 0.01 to ^ and the index of said aromatic pol^isocyanate/in the mixture is from 110 to 96, or (b) ^ mixture of/a prepolymer comprising polyether or polyester yfnits capped/by an aromatic poly-isocyanate, and water, .in whiclo^ase the scavenger is present in an amount not more than 8 parts by weight biased on the weight of the functional groups of the scavenger, per /LOO parts by weight of said prepolymer, and causing the resulting mixture to react, or in (c) the foam obtained by reacting a mixture as defined in (a) or (b), which mixture did not/contain scavenger.

It has baen discovered that the most effective scavengers are aliphatic (including cycloaliphatic and aryl aliphatic) mono-- or /poly-isocyanat;es, especially diisocyanates , such as bis (cyclohexyl-isocyanato)methane (•'),U'-methylencbiscyclohexyl diisocyanate) isopborone diisocyanate and bis (3 -me thy 1 - -i - i soc y an a tocyc lohexy 1) methane, as well as tris (6-isocvanatohexamethylene)-biuret ..and isocyanate XiPATENTOmCH IS JUNI974 V, J ~ (fe-fi78 185278 contain the corresponding polyamine. The term "aromatic amine" as used herein is intended to refer primarily to TDA but it also includes other aromatic amines formed from the corresponding poly-isocyanates. According to the present invention the amount of aromatic amine is reduced by introducing a "scavenger", generally prior to foaming, said scavenger being a material which can survive the foaming reaction to react with aromatic amines as they are generated. Accordingly the present invention provides a process for preparing a fluid-permeable (as hereinafter defined) hydrophilic polyurethane foam derived from an aromatic polyisocyanate which comprises incorporating a scavenger for aromatic amine which is a mono- or poly-aliphatic isocyanate, in a mixture of a prepolymer comprising polyether units of which at least 40 mole per cent are oxyethylene units capped by an aromatic poly-isocyanate, and water, the scavenger being present in an amount not more than 8 parts by weight based on the weight of the functional groups of the scavenger, per 100 parts by weight of said prepolymer, and causing the resulting mixture to react, or in the foam obtained by reacting such a mixture, which mixture did not contain scavenger.

It has been discovered that the most effective scavengers are aliphatic (including cycloaliphatic and aryl aliphatic) mono- or poly-isocyanates, especially diisocyanates, such as bis(cyclohexyl-isocyanato(methane) (4,4'-methylenebiscyclohexyl diisocyanate) isophorone diisocyanate and bis(3-methyl-4-isocyanatocyclohexyl) methane, as well as tris (6-isocyanatohexamethylene)-biuret and isocyanate 185273 IK* * AJ? derivatives of condensed fatty acids but other aliphatic isocyanates ete—weiA—as—other --material s—which—are—capable of roaofe* "S"8'1' with-an ar-omatic ami-no and which react more slowly with M(K y water (or not at all) than the aromatic isocyanate employed, can be used. For example,—organic oxirane oempound3—such a$ epoxidised soya bean oil and epichlorohydrin; epoxy resins derived from bisphenol A such as EPON/628 from Shell Oil Co.; organic anhydrides, in partipwrfar a carboxylic acid anhydride such as phthalic anhydrid^f trimellitic 10 ' anhydride, pyromellitic dianhydride/alpha-olefin/maleic anhydride copolymers, poly(maleirc anhydride) and oligomers thereof, styrene/malcic anhydride copolymers and alkyl vinyl ether/maleic anhydridexfopolymers; acyl halides such as benzoyl chloride, octanoyjl^chloride and sebacoyl chloride; organic 15 sulphonyl h^Tidos such as benzene sulphonyl chloride; and <S) carbo^ilTmides such as Isonate 143 L (by Upjohn) and Staboxo^I , b~=rti-ioo propylphenyl )car"bodiimidc)—by Naftono ;—I-ne . The scavengers can, of course, be used in mixtures or blends with one another if so desired. The preferred scavenger reacts only 20 slowly with water, polyols or isocyanate groups so as to survive the initial polymerisation reaction, but is capable of reacting rather rapidly with by-product aromatic amine moieties during the drying and/or storing of the polyurethane product.

M.2. PATENT OFRCET 2 2 AUG 1979 <S"07 S 185278 Although the theory of the formation of the aromatic amines as we^J. as the activity of the scavenger are not clearly understood, it Appears that aromatic isocyanates and possibly X their reaction prodiiets containing urea and urethane linkages are hydrolysectN^^ producl^^free aromatic amines which can be leached from the ps^lyurethane\^oam. The aliphatic diisocyanate or .other ocavongor- is "believed ncte. to compete successfully with the aromatic isocyanens^ for functional groups during the polymerisation reaction. ■anatse ror ru i. Therefore the al>^phatic isocyanate survives polymerisation and is believed to form urea addition products with aromatic amines as theseNare produced. These products appear to be more difficult to leach from the NX PATENT OFFICE 2 2 AUG 1979 RECEIVED I S-5 *7% 185278 A^:-cXir.%D Although the theory of the formation of the aromatic amines as well as the activity of the scavenger are not clearly understood, it appears that aromatic isocyanates and possibly their reaction products containing urea and urethane linkages are hydrolysed to produce free aromatic amines which can be leached from the polyurethane foam. The aliphatic diisocyanate is believed not to compete successfully with the aromatic isocyanate for functional groups during the polymerisation reaction. Therefore the aliphatic isocyanate survives polymerisation and is believed to form urea addition products with aromatic amines as these are produced. These products appear to be more difficult to leach from the 185278 V'v polyurethane foam and are also not believed to present a potential health hazard. It has also been found that the ^ resulting foams contain minor amounts of aliphatic amines which are hydrolysis products of the aliphatic isocyanates. 5 However, the aliphatic amines are not believed to present the ^ potential health problems raised by the aromatic amines.

A number of factors are important in reducing levels of TDA and optimising the effect of the scavenger. In general the residual aromatic amine content should be reduced to below 10 500 ppm. For example, foams which are stored while still wet tend-to exhibit a higher level of TDA than the corresponding foams stored following drying. Up to 8% by weight of scavenger based on the weight of the prepolymer is used; amounts of 4$> by weight or less are frequently satisfactory. Generally 15 amounts range from 0.01 to 8% by weight and preferably 0.1 to 4% by weight.

It should be understood that the weight percentage is based on _ the weight of the NCO groups, in tho casta an aliphatic isocyanate, and does not include the residual portions of the isocyanate molecule such as the aliphatic hydrocarbon residue 20 in the case of isophorone diisocyanate. —above percentageg — A-TT> also to tho other-organic-amino binding agents cmployoek U-S-Vl 0uU( WfoexTP-an acyl chloride-is—employed,—fche percentage—is based -or II tho function^]—groups—(■ C C1K Also, the use of certain catalysts has been found to be detrimental; accordingly it is 25 preferred that any catalyst employed be a "mild" catalyst which promotes reaction between the aromatic isocyanate and N.Z. PATENT OFFICE:' - b - . — 2 2 AUG 19791 RECBVPO 1 8527 hydroxyl groups of the polyol and permits the foaming reaction to proceed at a reasonable rate but does not cause undesirable side reactions involving either the aromatic or aliphatic isocyanate such as biuret formation or trimerisation, or cause the aliphatic isocyanate to be incorporated into the polymer. If conventional strong catalysts such as tin salts are employed, less than the usual amount should be used.

The optimum scavenger to be employed with a particular aromatic isocyanate can be determined by dissolving the 10 corresponding amine and the scavenger at equivalent (or greater) stoichiometric levels, i.e. enough of the scavenger is employed to react with one hydrogen atom in each group, in a common inert solvent. Within 16 hours at ambient temperatures the scavenger and amine should undergo a reaction which is 15 essentially irreversible and complete. Additionally, when dispersed in water, the scavenger should generally exhibit a _2 "or reaction rate with the water/ which is less than about 10 times the reaction rate of the aromatic isocyanate with the -3-5 water and preferably 10 - 10 times. In carrying out the test, separate aqueous solutions or dispersions of the aromatic isocyanate and scavenger can be prepared at a concentration of, _ 2 say, 10 moles/litre. The rate of reaction can be measured at, say, 25°C. In the event either the scavenger or aromatic isocyanate is insoluble in water; the test can be carried out 25 using constant agitation and suitable surfactants, or a suitable water-miscible cosolvent can be employed. It is <1^ Ii 185278 / believed that the above test procedure will furnish a useful • ■ , / guide, i.e. a "rough screen" in/selecting useful scavengers.

However, due to the complexity of the foaming process, the determination of utility of ^ny particulate scavenger should ■ ■ / be based on actual runs. / The foams produced according /to the present invention can be rigid, semi-rigid'' or flexible/ Generally, the foams possess a fluid-permealDle skin. By "fluid-permeable", as used herein, is meant that/ a section ox foam (1 inch thick) sliced ! I parallel to the surface and embodying said surface will 3 2 exhibit a permeability to air/of at least 0.25 ft. /minute/ft.

(/ // ■' U of foam using a pressure differential of 0.002 atmosphere. Similar test conditions are described in ASTM D-737 for measuring th^'permeability of fabrics. By contrast, foams / / -3 having a fairly dense ^km will measure less than about 10 3 '' 2 $ ft. /minut,e/ft. of foam using the above test. 7 y /in a preferred embodiment of the invention the process >/ V comprises foaming/(under conventional conditions) a mixture / / comprising: a)/an aliphatic isocyanate and b) a urethane / / prepolymer haying polyether or polyester backbone segments 4' . * . . ... capped with/an aromatic isocyanate, the aliphatic isocyanate s< being present in an amount not exceeding about 8 parts / ''preferably not exceeding about 4 parts, by weight per 100 parts by weight of said prepolymer, and c). water. The lower limit is not critical; it is determined by the degree of scavenging activity desired and also by the nature of the aliphatic isocyanate. Generally, a 8 N,Z- PATENT OTO#1 2 2 AUG 1979 I RECEIVED («a7* 185278 believed that the above test procedure will furnish a useful guide, i.e. a "rough screen" in selecting useful scavengers.

However, due to the complexity of the foaming process, the determination of utility of any particular scavenger should be based on actual runs.

The foams produced according to the present invention can be rigid, semi-rigid or flexible. Generally, the foams possess a fluid-permeable skin. By "fluid-permeable", as used herein, is meant that a section of foam (1 inch thick) sliced parallel to the surface and embodying said surface will 3 2 exhibit a permeability to air of at least 0.25 ft. /minute/ft. of foam using a pressure differential of 0.002 atmosphere.

Similar test conditions are described in ASTM D-737 for measuring the permeability of fabrics. By contrast, foams -3 having a fairly dense skin will measure less than about 10 3 2 ft. /minute/ft. of foam using the above test.

In a preferred embodiment of the invention the process comprises foaming (under conventional conditions) a mixture comprising: a) an aliphatic isocyanate and b) a urethane prepolymer having polyether backbone segments capped with an aromatic isocyanate, the aliphatic isocyanate being present in an amount not exceeding about 8 parts. preferably not exceeding about 4 parts, by weight per 100 parts by weight of said prepolymer, and c.) water. The lower limit is not critical; it is determined by the degree of scavenging activity desired and also by the nature of the aliphatic isocyanate. Generally, a o~ \i< level of not less than 0.01 parts^should 1^6 employed.

Suitable aliphatic isocyanates include cyc3/baliphatic isocyanates or aralkyl polyisocyanates/as well as/straight or branched aliphatic isocyanates, e£g. xylene-a0.pha'-diisocyanate, n-dodecyl isocyanate^ ethylene diisocyanate, n-butyl isocyanate, cyclohexyl Lsocyanate, ^rimethylene- / / diisocyanate, dicyclohexyl metliane-4, 4'-di'isocyanate, isophorone diisocyanate, 1,fefhexamethylene diisocyanate, 2,2,4-trimethyl-1,6-hexane/aiisocyanate and bis (3-rnethyl-4-isocyanatocyclohexyl)met^ane and mixtures thereof.

In preparing /oams by the: prepolymer technique, the prepolymer is generally admixed^/with a suitable blowing agent (e.g. water) and optionally a/catalyst and other additives (e.g. fire retardfants) depepfcling on the ultimate properties desired in the/foam. The/amount of water employed as a blowing ager^f is genera/ly from about 0.4 moles of I^O/mole of NCO groups to aboujf 1,000 moles of f^O/mole of NCO groups, for example 6.5 moles to 390 moles. In determining the amount f / of wat^fr or aqueous reactant such as an aqueous slurry suspension, or ^mulsion or an aqueous solution containing water-soluble material, the "mole of NCO groups" refers to the aliphatic groups of the scavenger as well as the NCO groups contributed by the prepolymer or by the aromatic isocyanate in a one-shot reaction mixture, but does not include the NCO groups theoretically required to react with all the hydroxyl groups of the polyol employed in the one-shot process . 1 fe<^7 185278 level of not less than 0.01 parts by weight should be employed.

Suitable aliphatic isocyanates include cycloaliphatic isocyanates or aralkyl polyisocyanates as well as straight or branched aliphatic isocyanates, e.g. xylene-alpha'-diisocyanate, n-dodecyl isocyanate, ethylene diisocyanate, n-butyl isocyanate, cyclohexyl isocyanate, trimethylene-diisocyanate, dicyclohexyl methane-4,4'-diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4-trimethyl-l,6-hexane diisocyanate and bis(3-methyl-4-isocyanatocyclohexyl)methane and mixtures thereof.

In preparing foams by the prepolymer technique, the prepolymer is generally admixed with a suitable blowing agent (e.g. water) and optionally a catalyst and other additives (e.g. fire retardants) depending on the ultimate properties desired in the foam. The amount of water employed as a blowing agent is generally from about 6.5 moles of F^O/mole of NCO groups to about 1,000 moles of J^O/mole of NCO groups, for example 6.5 moles to 390 moles. In determining the amount of water or aqueous reactant such as an aqueous slurry suspension, or emulsion or an aqueous solution containing water-soluble material, the "mole of NCO groups" refers to the aliphatic NCO groups of the scavenger as well as the NCO groups contributed by the prepolymer^ -;„._£:Cj984 " , 185278 For one-shot foams, the amount of /rater employed* is preferably from about 0.40 to about O.55.mo/es of I^O/mo^/e of NCO groups (exclusive of NCO groups required for reaction with the polyol). In preparing foams by the prepolymer process the amount of water employed is preferably^ from about yO.40 to about 1.0 moles F^O/mole of NCO groups, The urcthanc pi/epolymer employed comprises polyether or polyester backbone/segments capped with an aromatic isocyanate /e.g. toluen/ diisocyanate; TDI). Suitable polyether prepolym^rs include tfne polyalk.ylene oxide ethers, such as the reaction products' of ethylene oxide, propylene oxide, butylene oxide,/styrene oxifle, picoline oxide or methyl glycoside, wiith a compound containing two or more reactive hydrogens, ^uch as watex, resorcinol, glycerol, trimethylol propane, 2,6-hexane/riol, pentaerythritol, sorbitol, ethylene glycol ,dliethylene glycol and triethylene glycol; typically the prepolymer is/the reaction product of a polyoxyethylene polyol, especially a glycol, and a monomeric alcohol having at least 3 hydroityl groups, per molecule, especially an aliphatic alcohol havimg 3 hydroxyl groups per molecule, said reaction product beijag capped with an aromatic isocyanate. Other polyethers includeXsolyoxypropylene glycol, polyoxyethylene glycol, polyoxybutylene glycol, polyoxyethyleneoxypropylene glycol, polyoxyethyleneoxybutylene glycol and polyoxypropyleneoxy-butylene glycol. Hydrophilic polyethers are preferred.

Preferably, the polyether urethane prepolymers - • ? »"•. ' v..-,; - ' \ ■ ■ , , . L N2. PATENT OFFICE 2 2 AUG 1979 I received /V'V The urethane prepolymer employed comprises polyether backbone segments capped with an aromatic isocyanate (e.g. toluene diisocyanate; TDI). Suitable polyether prepolymers include the polyalkylene oxide ethers, such as the reaction products of ethylene oxide, propylene oxide, butylene oxide, styrene oxide, picoline oxide or methyl glycoside, with a compound containing two or more reactive hydrogens, such as water, resorcinol, glycerol, trimethylol propane, 1,2,6-hexanetriol, pentaerythritol, sorbitol, ethylene glycol,diethylene glycol and triethylene glycol; typically the prepolymer is the reaction product of a polyoxyethylene polyol, especially a glycol, and a monomeric alcohol having at least 3 hydroxyl groups, per molecule, especially an aliphatic alcohol having 3 hydroxyl groups per molecule, said reaction product being capped with an aromatic isocyanate. Other polyethers include polyoxypropylene glycol, polyoxyethylene glycol, polyoxybutylene glycol, polyoxyethyleneoxypropylene glycol, polyoxyethyleneoxybutylene glycol and polyoxypropyleneoxy-butylene glycol. Hydrophilic polyethers are preferred.

Preferably, the polyether urethane prepolymers fa /* A , -3-OEOS9844 I 1 852 78 employed are hydrophilic in that at least 40 mole % of the oxyalkylene units in the prepolymer backbone are oxyethylene units with the balance being oxypropylene, oxybutylene or other oxyalkylene units. In the resulting polyurethane foams, the branch-points of the polymer chains are connected by essentially linear polyoxyalkylene chains containing at least 40 mole % of oxyethylene units (excluding initiators at branch-points). Preferably, the oxyethylene content is from about 55 or 60 to 75 mole %. At oxyethylene levels of 40-60 mole %, it may be desirable to use a surfactant to promote dispersion of the prepolymer in water prior to foaming. Conventional surfactants for this purpose can be used, for example non-ionic surfactants, in particular polyether based surfactants such as those known under the Tradename Pluronic derived from polyether alcohols as well as those derived from a higher aliphatic alcohol such as stearyl alcohol, and a polyether alcohol and silicone surfactants, for example derived from a silicone ester and a polyether alcohol.

Suitable prepolymers can be prepared by capping a polyoxyalkylene polyol with an excess (generally between about 1 to about 4, preferably about 2 to about 3, isocyanate groups to hydroxyl group) of aromatic polyisocyanate in a conventional manner, typically in an inert moisture-free atmosphere at 0° to 120°C for, say, 20 hours. Prior to capping, the polyol suitably has a molecular weight of from 200 to 20,000, preferably from 300 or 600 to 6,000. The hydroxy functionality I 185278 of the polyol and the corresponding isocyanate functionality following capping is generally from 2 or 3 to, say, 8. If foams are formed from prepolymers with an isocyanate functionality of about 2, the resulting foam is essentially linear and does not have as much tensile strength as crosslinked foams. Accordingly, if the isocyanate functionality is about 2, a crosslinker can be employed, for example by addition to the water in which the prepolymer is dispersed, although the linear non-crosslinked foams can be prepared. To minimise adverse reactions involving the aliphatic isocyanate, any crosslinkers employed should desirably be aliphatic polyols (e.g. TMOP (trimethylol propane), glycerol or pentaerythritol) rather than amines.

Examples of suitable polyols (to be capped with polyisocyanates) include: (A) essentially linear polyols formed, for example, by reaction of ethylene oxide with water, using ethylene glycol or higher molecular weight glycols as an initiator. Where the linear polyethers are derived from mixtures of ethylene oxide with, e.g., propylene oxide, the polymer can be either a random or a block copolymer and the terminal units can be either oxyethylene or oxypropylene.

(B) those with a hydroxy functionality of 3 or more. Such polyols are commonly formed by reacting alkylene oxides or mixtures, as described above, with a polyfunctional initiator such as trimethylolpropane or pentaerythritol.

(C) linear or branched polyfunctional polyols as exemplified in A and B above prepared together with an N.Z. PATENT omcgi 2 2 AUG (979 t R PT'Cn/crr* / initiator or crosslinker, for/example a iriixture of ii polyethylene glycol (m. w. say 1,000) with trimethylolpropane / / trimethylolethane or glycerine. This;/mixture can be reacted subsequently with excess polyisocyanate. Alternatively, the linear or branched polyo/s (e.g. polyethylene glycol) can be / reacted separately with/excess polyisocyanate. The initiator, 8 e.g. trimethylolpropanje, can also^fbe reacted separately with / J polyisocyanate. Subsequently, the two capped materials can be combined to formyxhe prepolyftier. i / Suitable polyisocyanates useful in preparing prepolymer f i include polyaryli^ocyanates ^uch as PAPI, triphenylmethane-4, 41,4",-triisocyanate, benz^e-1,3,5-triisocyanate, toluene-2,4,6 triisocyanate, Miphenyl-2 ,/4, 4'-triisocyanate, xylene / ' / diisocyanate,/chlorophenylene diisocyanate, diphenylmethane-4,4* diisocyanate/ 3,3'-dime^hoxy-4, 4'-biphenylene diisocyanate, / 2, 2 ' 5, 51 -te/tramethyl-4(; 4• -biphenylene diisocyanate, 4,4'-methylenel/is( phenyl isocyanate), 4,4'-sulphonylbis(phenyliso-cyanate)/ 4,4'-methylene di-ortho-tolylisocyanate, toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, commercial mixtures of toluene-2,4- and k,6-diisocyanates, m-phenylene diisocyanate, 3,31-diphenyl-4^4'-biphenylene diisocyanate, 4,4'-biphenylene diisocyanate, i,3'-dichloro-4,4'-biphenylene diisocyanate, 1,5-naphthal^iediisocyanate, cumene-2,4-diisocyanate, 4-methoxy-l i3-phenylenediisocyanate, 4-chloro-l,3-phenylene-diisocyanatfe, 4-bromo-l, 3-phenylenediisocyanate, 4-ethoxy-l, 3- phenylenediisocyanate, 2,4*-diisocyanatodiphenylether, H 1 . -1 !%07& 185278 ;,\ r*. p initiator or crosslinker, for example a mixture of polyethylene glycol (m. w. say 1,000) with trimethylolpropane, trimethylolethane or glycerine. This mixture can be reacted subsequently with excess polyisocyanate. Alternatively, the linear or branched polyols (e.g. polyethylene glycol) can be reacted separately with excess polyisocyanate. The initiator, e.g. trimethylolpropane, can also be reacted separately with polyisocyanate. Subsequently, the two capped materials can be combined to form the prepolymer. include polyarylisocyanates such as PAPI, triphenylmethane-4, 4',4",-triisocyanate, benzene-1,3,5-triisocyanate, toluene-2,4,6-triisocyanate, diphenyl-2,4,4'-triisocyanate, xylene diisocyanate, chlorophenylene diisocyanate, diphenylmethane-4,4'-diisocyanate, 3,31-dimethoxy-4, 41-biphenylene diisocyanate, 2,2'5,5'-tetramethyl-4,41-biphenylene diisocyanate, 4,4'-methylenebis(phenylisocyanate), 4, 4*-sulphonylbis(phenyliso-cyanate), 4,4'-methylene di—ortho-tolylisocyanate, toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, commercial mixtures of toluene-2,4- and 2,6-diisocyanates, m-phenylene diisocyanate, 3,3'-diphenyl-4,4'-biphenylene diisocyanate, 4,41-biphenylene diisocyanate, 3,3•-dichloro-4,4'-biphenylene diisocyanate, 1,5-naphthalenediisocyanate, cumene-2,4-diisocyanate, 4-methoxy-l,3-phenylenediisocyanate, 4-chloro-l,3-phenylene-diisocyanate, 4-bromo-l,3-phenylenediisocyanate, 4-ethoxy-l,3-phenylenediisocyanate, 2,4'-diisocyanatodiphenylether, 4,4'-diisocyanatodiphenylether, and 4,6-dimethyl-l,3- Suitable polyisocyanates useful in preparing prepolymers phenylenediisocyanato. 13 )65278 4,4'-diisocyanatodiphenylether, and 4# 6-dimethyl-l, 3-phenylenediisocyanate.

Useful polyester polyols include the reaction product / of polyfunctional organic carboxylic ^icids, for example dicarboxylic aliphatic acids such as succinic, auipic, sebacic, azelaic, glutaric, pimelic acids and dicarboxylic aromatic acids such as phthalic acid, ter^phthalic a<~^ anc^ isophthalic acid as well as "dimer acids" s&ch as the calmer of linoleic acid and hydroxyl-containing nranocarboxyl^c acids such as ricinoleic acid or anhydride^ thereof an& polyhydric alcohols / for example monomeric polyhydric alcohols such as glycerol, / ■ f 1,2,6-hexane triol, ethylene glycol, rtrimethylol propane, ' / / trimethylol ethane, pentaerythritol* propylene glycol, i * 1,3-butylene glycol, arid 1,4-butyJene glycol. Generally these polymers have a molecular weight/ of 300-6000; polyols such ' / /' as glycerol, TMP, and pentaerythritol can be employed to provide crosslinkang. Typically the hydroxyl number will be / r 50-100 although/values as h/gh as 450 can be used in preparing rigid foams. / / , Alt-ernatively a one-shot process is used by foaming i $ \using conventional techniques) a mixture typically comprising: 5 jj jjpQ ^ "PofMHe rt/yfAfS. • a) alipha"tic isocyanafte,/ b) aromatic isocyanate —&e&venrgw- ^ $ i ^ fui- uimiuLiu mulim / c) a polyether or polyester polyol, and / ' / d) a ^atalyst system for promoting reaction between the aromatic isocyanate and |me hydroxyl groups of the polyol as well as water. In th^'mixture the aliphatic isocyanate index is from 0.01 to 4 generally 0.2 to 4 and the aromatic isocyanate index is from about 110 to about 96 especially about 99.8 to about 96.

I W78 185278 ,A u r'^iv7 ^ After the foam has been prepared it is desirably dried. It is also possible to treat the foamed polyurethane with a scavenger. This can be done by imbibing the scavenger into the product using a liquid vehicle such as water or an organic solvent or by exposing the product to the scavenger in the form of a gas, vapour or aerolised spray medium.

The foams of this invention are useful for, inter alia, decorative, cushioning, insulative, sound deadening, protective and fire retardant surfaces. Accordingly, these foams may form strippable coatings for protecting articles during handling and shipment. Also, because the foams are easily sterilised and are low in undesirable residuals, they find great utility as household, industrial and/or health care, cosmetic, dental or biomedical/surgical products. The feature of fluid (water vapour) permeability of these materials renders them attractive for apparel.

Catalysts, antioxidants and other chemical reactants may be supported on the foams for use in, for example, enzymatic reactions, fuel cells, filters, water or blood purification, extraction applications and in separation systems.

DEC 1984 -Cr'' u-> p.-r V1 NOW _ v ki*H3 165278 i.r07<Jr The expression "index" is used conven-tyionally to indicate the ratio of the actial amount of aromatic or aliphatic isocyanate in the reaction mixture^ to the theoretical amount of isocyanate needed for reaction wath all active hydrogen compounds present in the reaction mixtur^, multiplied by yOO Of course for scavengers other than ths^ isocyanates the Zndex indicates the ratio of equivalents of/the scavenger gr^up to the equivalents of all active hydroc/en compounds inii^_ally present in the reaction mixture, multiplied by 10 0"/ufLci "10 0 . Conventional catalyst systems can be empjroyed in conventional manner in preparing the one-shot fo/ims of the invention. However, it has been found that marfy catalysts increase the amount of aromatic amines in they foams and accordingly the amount ofyfcatalyst employed/should be held to a minimum consistent wit/i obtaining a desVrable rate in the foaming reaction as we/1 as desirable properties in the finished foam. As discussed afcove, suitable catalysts should promote reaction between th/ polyol and the I^CO groups of the aromatic isocyanate and should be employed u/der conditions where detrimental sid<y reactions (e.g. mrimerisation, dimerisation and biuret formation) are minimiysed. Conventional catalysts for promoting^ the NCO/alcohol /eaction are set forth at Table LXX (page 212) of Saunders and Frisch, Polyurethanes Chemistry And Technology (p/rt I), 1962, John Wiley & Sons: the TabLe below illustrates some suitable amounts thereof (in parts df catalyst/100 pa^rts by weight of the polyol) is set fort!/ below. According to conventional practice, catalysts are/frequently used mixtures and thus the actual amounts [(ployed may vary considerably; the total amount should be :ept to a minimum.

N.2. PATENT OFFICE: 2 2 AUG 1979 RECEIVED AS AMENDE! Now amExixml ,1 The expression "index" is used/conventionally .to indicate the ratio of the actual amoui aliphatic isocyanate in the reaction/mixture tc? the theoretical amount of isocyanate needed for reaction with/all active hydrogen compounds present in the reaction inixture, multiplied by 100 .

Conventional catalyst systems can toe employed in conventional manner in preparir^j the one-shot foams of the invention. However, it has been found, th<at many catalysts increase the amount of aromatic amines ifn the foams and / / accordingly the amount of catalyst employed should be held to a minimum consistent with^obtaining a/desirable rate in the foaming reaction as wellj/as desirabl^ properties in the finished foam. As discussed above, suitable/catalysts should promote reaction between the lpolyol and thh NCO groups of the aromatic isocyanate and shoulp be employee^under conditions where detrimental side reactions (e.g.// trimerisation, dimerisation and biuret formation) are minimised. Conventional catalysts / > for promoting tqe NCO/alcohol /reaction are set forth at ;//■ Table LXX (pag^ 212) of Saunters and Frisch, Polyurethanes: Chemistry an^'Technology {'Pa.Tct I), 1962, John Wiley & Sons: the Table b^'low illustrates some suitable amounts thereof (in / / parts of catalyst/100 par^s by weight of the polyol) is set forth bel^w. Accordingjj-o conventional practice, catalysts are frequently used as fixtures and thus the actual amounts employed may vary considerably; the total amount should be t :to a minimum. 185278 Examples 1-8 Use of Various Aliphatic Diisocyanates to Reduce Toluene Diamine (TDA) Levels in Polyurethane Foams Polyurethane foams were prepared using the prepolymer technique by reacting 200 g of Prepolymer A, B, or C (described below) with 200 g of water containing 4 g of surfactant. With the exception of Examples 6-8, the surfactant employed was Pluronic L-62 (BASF-Wyandotte), a nonionic polyether-based surfactant. In Examples 6-8 the surfactant was Brij 72 (Atlas Chemicals Division of ICI, America, Inc.), a stearate surfactant. In the control foam using Prepolymers B and C, the Brij stearate surfactant was also employed. In the control foam using Prepolymer C as well as in Example 8, the amount of Brij surfactant employed was about 0.5 weight percent based on the weight of the prepolymer. trimethylolpropane (TMOP) and Carbowax 1,000 (a polyoxyethylene glycol, Union Carbide and Chemicals Corp.) with toluene diisocyanate (TDI). Sufficient amounts of the mixtures were employed so that on the basis of molar equivalence the ratio of TDI/TMOP/glycol was 7.1/1/2. Analysis of the prepolymer for free TDI showed it to contain 3% by weight. The TDI was added in two stages. First, sufficient TDI was added to react with 95% of the hydroxyl groups followed by addition of the remaining portion of the TDI. Several hours was allowed between additions to promote chain extension in the prepolymer.

Prepolymer A was prepared by capping a mixture of m « Catalyst Tertiary Amines Tin . Salts N-ethylmorpholine (0.2-1.0) Triethylenediamine ' (0.05-1.5) Triethylamine (0.3-1.5) N,N-dimethyl,-N1,N'-dimethyl-1,3-diamino-butane (0.2-1.0) i ■ I z K) N K) "0 > > —f m c: CD H mm* 1 3 sO O m Stannous octoate (0.01-0.5) Dibutyltindiacetate (0.01-0.5) DibutyT&indilaurate (0.01-0.5) Dibutyltindioctoate (0.01-0.5) Fe Salts Ferric 2-ethylhexanoate (0.05-1.0) Ferric chloride ?&V©3-1.0) Ferric acetyta-c^etonate (0.03-1.5) Miscellaneous Catalysts Cobaltnaphthenate (0.01-1.0) Tetrabutyl Titanate (0.01-1.2) Lead oleate (0.01-1.0) D i e thyl^ejiet r i am i n e (0.2-1.5) 185278 Prepolymer B was prepared using the same reactants as Prepolymer A except that the TDl/TMOP/glycol ratio was 6.7/1/2. The prepolymer contained 1% by weight of free TDI.

Prepolymer C was prepared according to the method 5 used to prepare Prepolymer A except that ethylene glycol was used as an additional reactant. The ratio of reactants used was TDl/TMOP/polymeric glycol/ethylene glycol of 8.6/1/2/1.

The foams prepared as described above were analyzed for TDA by extracting 20 g of each foam 7 times with hot water 10 followed by evaporation of the water. The extraction technique consisted of immersing 20 g of foam in 150 ml of deionized water at 38° C in a beaker for 5 minutes while compressing the foam several times with a spatula. This procedure was repeated 7 times with fresh water, ringing the foam as dry as 15 possible between extractions. The combined extracts were filtered to remove any solid particles of foam and concentrated to approximately 50 ml in a rotary evaporator. The concentrate was evaporated to dryness in a beaker on a hot plate to obtain from about 0.134 g to about 0.330 g of dry extract. 20 At no time was the temperature allowed to exceed 60° G. The TDA content of the extracts was determined and the results are set forth in Table I. - y/-% 2 7 8 In the one-shot process all off the ingredients, e.g. the polyether or polyester polyol, thy aromatic isocyanate, the aliphatic isocyanate, th^ blowing agent, catalyst, and any // / additional components such^as UV absorber, surfactant, fire / / retardant additive and fil/lers, are/mixed together and poured / onto a surface or into a/mould whe^e foaming takes place ! according to conventional procedures (see, for example, United States Patent No. 3,79|6,508 and British Patent Specification No. 1,368,625). Suitable aromatic and aliphatic isocyanates, / / and polyols are as ^escribed above for the prepolymer process.

After the/foam has lolen prepared it is desirably dried. It is also possible to treat/the foamed polyurethane with a scavenger. This/can be done by imbibing the scavenger into the product using a liquid/vehicle such as water or an organic solvent or by/exposing the product to the scavenger in the form of a ga/, vapour or/aerolised spray medium. foams of this invention are useful for, inter alia, decorative/, cushioning,/ insulative, sound deadening, protective and fire/retardant surfaces. Accordingly, these foams may form strippaple coatings fior protecting articles during handling and sl^lpment. Also,/because the foams are easily sterilised and afre low in undesirable residuals, they find great utility as Household, industrial and/or health care, cosmetic, dental or^biomedical/sujgical products. The feature of fluid (water vapour) permeabi/lity of these materials renders them attractive ' I :or apparel. / • • TABLE I Example Control 1 2 3 4 X 6 41 Control 7 Control 8 Aliphatic Extract Prepolymer Isocyanate (%) (Weight %) A A A A A A A B B C C none *IPDI (0.5%) IPDI (4%) **MBDI (1%) MBDI (8%) none IPDI (5%) none IPDI (5%) none IPDI (5%) 1.40 1.38 1.08 1.65 0.97 0. 77 0.67 1.26 0. 84 1.20 0.76 *IPDI = isophorone diisocyanate **MBDI = 4,41-methylenebis (cyclohexyl isocyanate) • m Aromatic Amine (tolylene diamine) In Extract (PPM) 2590 1930 1330 1180 none detectable 1300 none detectable 2270 none detectable 1000 none detectable Calculated Amount (PPM) of tolylene diamine in original forai 36 27 14 20 none detectable 10 none detectable 18 none detectable 12 none detectable 1 852 7 Catalysts, antioxidants and other chemical reactants may be supported on the foam's for use /in, for example, <^ells, filters, enzymatic reactions, fuel purification, extraction ^application? s and in separation systems. water or blood / -"Uj AS! A5&2NEJSD i 185278 From the above Table it can be seen that for the isocyanate foam of Example 1, the initial diamine level, calculated at 36 ppm, decreased significantly as the amount of aliphatic isocyanate employed was increased. Comparison of Examples 1, 2 and 6 shows a steady reduction of 27 to 14 to the point where none was detectable. Similarly for methylenebis (cyclohexyl isocyanate) comparison of Examples 3 and 4 shows a similar decline. This decline is unexpected because each of the aliphatic diisocyanates was difunctional and some participation in the polymerisation reaction would seem probable. However, despite the presence of the exothermic polymerisation conditions, the presence of the aliphatic isocyanate still exhibited a significant influence on the amount of residual total extract and free tolylene diamine in the foam. 11 1^3 DEC 1984 j 18 now AMENDED 1 85278 From the above Table it can b/ seen that for the isocyanate foam of Example 1, the initial diamine level/ calculated at 36 ppm, decreased significantly as the afmount of / aliphatic isocyanate employed was ^increased. Compaj^Lson / of Examples 1, 2 and 6 shows a steady reduction off 27 to 14 j // to the point where none was detectable. Similarly for methylenebis (cyclohexyl isocyanate) comparison of Examples 3 and 4 shows a similar decline. This decline is unexpected ✓ because each of the aliphaitic diisocyanate^ was difunctional ./■ / and some participation in the polymerisation reaction would / / seem probable. Howeve-r, despite the presence of the exothermic / / polymerisation conditions, the presence of the aliphatic // A r isocyanate still exhibited a significant influence on the amount of residual total' extract and fre<s tolylene diamine in the foam.

/ Examples 9-yl8 / / / Preparation and7Analysis of T / One-shot Polyurethane Foams / / Trade name designations in Examples 9-18 are as follows: NIAX Polyol 1646 (Union/barbide) NIA^yPolyol 60-58 . (Uni on C a rb i de) /' / a NIAX LG-56 /• / (Union Carbide)/ /.

Formrez 50 /, (Witco Chemical Co.) / ethylene oxide/propylene oxide copolymer ethylene oxide/propylene oxide copolymer propylene oxide polyol (m. w. = 3,000) polyester (adipic acid/ diethylene glycol) glycol, m. w. = 2,000, hydroxyl number ~-=] 50 N.Z. PATENT OFFICE 2 2 AUG 1979 I received N'&S/AFv'END'iD ■ - ■ -s* \urvwv ,1" J,S'D .i / Freon 11 (DuPont) Silicone L-520 (Union Carbide) Silicone L-5320 (Union Carbide) NIAX Catalyst A-l (Union Carbide) DABCO (Air Products) XDI-1421 (The Dow Chemical/to.) Hylene W (DuPont) DDI-1410 (General Mill ;) Fryol FR-2 (Stauffer) Armeen D-10-D I /< / 1 8 7 zrichlorofluoromethane hydrolyzable silicone / surfactant (silicone ester/ j polyether alcohol reaction product) silicone surfactant tertiary amine/glycol admixture triethylenediamine polyoxyethylene triol (> 50% end-capped with secondary hydroxyl groups) 1,1*-methylenebis(4-isocyanatocyclohexane) stearic acid dimer diisocyanate tris-2,3-dichloropropyl phosphate dimethylhexadecylamine (Armak Co/) Foams (designated A-E) were prepared using the one-shotf technique amd formulations as described below.

I ili - - 1 8527 Five sample foams were prepared from ieach formulation and the residual aromatic amine coiytent from!the five samples was averaged to give the valuob shown in Table II (below). Also, five control foams (no adflitive) were prepared from each formulation with the aromatic amine values shown in Table II J I being the average of th4 five. Iri Table II the aliphatic isocyanate employed in /the odd-nu|nbered examples was Hylene f 1'/ W. The aliphatic isoqyanate employed in the even-numbered i' examples was DDI-1410/ The foam' formulations employed in the I i examples are as follows: Formulation A (Examples 9,10); ji Formulation B (Examples 11,12):' Formulation C (Examples 13, 14) 7 Formulation D (Exanjples 15,16)/; and Formulation E (Examples 17, 18). /• h I; now amended} ^AMENDED,] TABLE II NOW AMENDED' 165278 Foams were prepared as follows/ The number in parentheses, following the ingredient is/the partes by weight ■/ / of said ingredient. » j' / / Formulation A was prepared by admixing NIAX Polyol / / 1646 (100), distilled water (3), irluorocarb'on 11 (3) and /■' silicone L-520 (2) to form mixture 1. NIAjX catalyst A-l (0.2), stannous octoate (0.35),/ toluene /diisocyanate 80/20 (49.5) / . / / and either Hylene W (6) or DDI-1410 (6$ were admixed to form / I mixture 2. Mixtures 1 and ,2 were combined and stirred for / / about 10 seconds followed//by formation of a very soft / / polyurethane foam (Foam A). / / / Formulation B' was prepared by admixing NIAX polyol / / 60-58 (100), distilled water (4'), Silicone L-520 (2), and DABCO (0.15) to foi^n mixture 1. N-ethylmorpholine (0.60), stannous octoate /0.15), TDl/80/20 (50) and either Hylene W (6) or DDI-l4lO/(6) were apnixed to form mixture 2. Mixtures 1 and 2 were combined and^ stirred for about 10 seconds followed by production of a flexible polyurethane foam (Foam B).

/ / Formulation iC was prepared by admixing NIAX LG-56 / / (100), Fryol FR-2 (2^)^ distilled water (4) and Silicone L-520 / / (1) to form mixture''1. NIAX Catalyst A-l (0.1), stannous octoate (0.35), TED I 80/20 (50.7) and either Hylene W (6) / or D$I-l4l0 (6) /were admixed to form mixture 2. Mixtures 1 afod 2 were combined and stirred for about 10 seconds followed r It by productior^ of a polyurethane foam having flame retardant properties ("Foam C).

NX PATENT OFFICE " 26 " 2 2 AUG 1979 I * 1 85273 Formulation D was prepare (100), distilled water (3.8), Armeen DM-16-D (0.3) to form m (1.9), TDI 80/20 (44.9) and ei DDI-1410 (5.8) were admixed and 2 were combined and sti/red by production of a polyes Formulation E was prepar distilled water (3.0) arid Silico 1. Triethylamine (0.2.5), stann< (34.0) were admixed Arith eithe; ng Formrez 50 (1.0) and ethyl morpholine 5.8) or Mixtures 1 seconds followed admixing XDI-1421 (100), 0.1) to form mixture (0.075) and TDI 80/20 .36) or DDI-1410 (5.36) to form mixture 2. Mixtures 1 and 2 were combined with J stirring for abouft 10 seconds to produce a hydrophilic polyurethane f c$am ( Foam EJ.

Ana/ysis of thfe foams of Table II to obtain the / residual argfhatic amine values was carried out using thin layer chromatography in a method very similar to that described^by Kottempa (J. A. 0. A. C., 49 (5), 954-959 (1966)). Visualization using ultraviolet light was aided by spraying the plates with Fluram (4-phenylspiro[furan-2(3H),-1'-phthalan]-3,3'/dione), by^Roche Diagnostics).

In Jthe analytical method a foam sample weighing ■2 g (weighed to the nearest mg) is covered with 75 ml of /methanol i^ a 250 ml beaker and soaked for 5 minutes with occasional- compression. The methanol is decanted by squeezing ... y. u ™ / 185278 twice with fresh methanol, and th® combined Qxtracts are concentrated to 25 ml for further analysis. ^ Standard solutions of 2,4- and 6-toluene diamine (hereinafter TDA) are prepare^ in methanpl and contain 20, 16, 12, 8, 4 and 2^g/ml. The Standard solvations and the unknown extract (using 20 inicrolitres/of each) are spotted at 7 positions equidistant from eac^ other with each spot being 3 cm from the bottom of a standard 20 cm x 20 cm silica gel TLC plate. The unknown occupies/the seventh position at one side of the plate. ^After the ^pots have dried, the plate is placed in a developing tank containing 120 ml of chloroform, 33 ml of ethyl aefetate, 20 of ethanol and 7 ml of glacial acetic acid. Development takes about one hour and is complete / when the developing solution reaches a line 15 cm above the / bottom of t^-e plate. 5fhe plate i^ dried in a horizontal position for 5-10 minutes §;nd then spr&yed uniformly in a vertical position with oty Fluram in acetone. The spots which appear approximately 6 cjft (2,4-isomer) and 8 cm (2,6-isomer) above the bottpm of the pJfate can be located with ultraviolet light, / / e.^j. a long-wa^e hand-held BLAK RAY model UVL-60 from a 0.015% soluton ^traviolet products, I nc. The sides of the plate are marked / U/ if ,7 v /' to indicate/the line through which the plate is to be scanned.

/The plate is placed in an Aminco-Bowman Spectrophoto ^/' Fluorime?ter (Model J4-8427) with a Model J10-280 photomultiplier / microphotometer having a strip chart recorder with a 10 millivolt / i 65278 full-scale output attached t hoc etc/. The excitation wavelength in the scanner is adjusted to 39.0 nm and the resulting visable light spot is adjusted/to scan across the line of TDA spots. The emission wavej/ength is set at 500 nm. The • / / plate is scanned starting wi£h the strongest standard spot to generate a chart showing relative /fluorescence of the TDA isomer spots as a series c/f curves wh4rein the light is proportional to the concentration oj TDA in the unknown.

Peak heights ,are measured from the baseline and are / / plotted. The concentration of TDA in the extract is then / calculated from the known concentrations of the standard // solutions. This vaiLue, expressed as ppm in the original / / foam, is obtained/using the following equation: a TDA, ppm in foam = /TDA in extract, ^<q/ml) (ml extract) foam weight, g.

To i/lustrate use/of the above equation, if a 2.0 g foam sample generates 25.(j ml of concentrated extract containing 5.7 / g/ml of 2/4-TDA, the foam sample contains / / approximately 71 ppm of 2,4-TDA.

The precision/of the above method is + 30% at a level of$ 20 ppm.

Examples 19-25 / Use of BisJC 3-methyl-4-isocyanato) cyclohexylmethane as / / .

/ Scavenger for Aromatic Amines f Various ^mounts of bis( 3-methyl-4-isocyanato) cyclohexylmethan were admixed witty two different hydrophilic urethane prepolymers W.Z. PATENT OFFICE NOW 2 2 AUG 1979 jj RacnVED 4.3 NOW AMEIMD£ 1 8 52 7 (Prepolymers F and G) prior to foaming. Foaming tos carried out by admixing the prepolymer (WO parts), watelr (100 parts) and a surfactant (2 parts). Thd surfactant employed was Pluronic L-62 (BASF/Wyandotte)/ The resulting foams were analysed for their residual ^ontent of arom&tic amines according to the method set forth in Examples 9-18,/and the results are set forth in Table III.

Prepolymer F -wAs prepared by/admixing polyethylene glycol (M.W. = 1,000) ^Lth TMOP. Sufixicient TDI was added to cap 95% of the hycUroxyl groups present followed by further addition of/TDI to provide/ a theoretical excess of 10% TDI. Following the initial Addition of TDI, the admixture was allowed to r^act for several hours before the final 15% TDI was added. /The mole ratios of PEG l.OOO/TMOP was 2/1.

Prepolymer G was prepared following the same general procedure as/Prepolymer F with the exception that the PEG 1,OOO/TMOPXatio was 2/0 J66. Also, only 92% TDI was added during th<§ first addition. Following a reaction period, an additior^al 13% TDI wa/ added.

In control/1 and Examples 19-22, Prepolymer F was emplq^ed. In cont/ol 2 and Examples 23-25, Prepolymer G was Employed. / f, '/ * // <» E III Residual Aromatic Amine (PPM) "Foam prepared by machine equipped with a mixing head.

'Foam was analyzed when wet immediately after foaming.

Foam was analyzed after drying in air overnight.

^Foam was analyzed after drying for 30 minutes with forced air at 60-70°C,

Claims (3)

WHAT WE CLAIM IS: AS AMENDED

1. A process for preparing a fluid-permeable (as hereinbefore defined) hydrophilic polyurethane foam derived from an aromatic poly-isocyanate which comprises incorporating a scavenger for aromatic amine which is a mono- or poly-aliphatic isocyanate in a mixture of a prepolymer comprising polyether units of which at least 40 mole per cent are oxyethylene units capped by an aromatic poly-isocyanate, and water, the said scavenger being incorporated in an amount not more than 8 parts by weight based on the weight of the functional groups of the scavenger per 100 parts by weight of said prepolymer, and causing the resulting mixture to react, or in the foam obtained by reacting such a mixture, which mixture need not contain scavenger.

2. A process according to claim 1 in which the scavenger

< -2

exhibits a reaction rate with water which is less than 10

times the reaction rate of the aromatic poly-isocyanate with water.

3. A process according to claim 1 or 2 in which the aliphatic isocyanate is 4,41-methylenebiscyclohexyl diisocyanate, isophorone diisocyanate, bis (3-methyl-4-isocyanatocyclohexyl)methane, tris(6-isocyanatohexamethylene)-biuret or an isocyanate derivative of a condensed fatty acid.

4. A process according to any one of the preceding clainis in which the foam is dried after preparation.

claims in which the scavenger exhibits a reaction rate with

A process according to any one of the preceding

_3

water which is less than 10 times the reaction rate of the.1 aromatic polyisocyanate with water. |

\ \

•6 DEC 1984

\

20

(*^7S 185278

/.\ rv

6. A process according to any one of the preceding claims in which at least 60 mole % of the oxyalkylene units are oxy ethylene.

urethane prepolymer is the reaction product of a polyoxyethylene polyol with a monomeric alcohol having at least 3 hydroxyl groups per molecule, capped with an aromatic poly-isocyanate.

8. A process according to claim 7 in which the alcohol is an aliphatic alcohol having 3 hydroxyl groups per molecule and the polyol is a polyoxyethylene glycol.

9. A process according to any one of the preceding claims in which the aliphatic isocyanate is present in an amount from 0.1 to 4% by weight of said prepolymer.

10. A process according to any one of claims 5 to 9 in which the water is present in an amount from 6.5 to 1000 mole H20/mole of NCO groups.

11. A process according to any one of claims 5 to 10 in which the water is present in an amount from 6.5 to 390 mole I^O/mole of NCO groups.

12. A process according to claim 1 substantially as hereinbefore described.

13. A process according to claim 1 substantially as described in any one of Examples 1 to 4 and 6 to 8.

14. A fluid-permeable hydrophilic polyurethane foam whenever prepared by a process as claimed in any one of the preceding claims.

15. A composition for preparing a polyurethane foam comprising: v

7. A process according to claims 5 or 6 in which the

\

21

I %«Ti78

185278

m

(a) an aliphatic isocyanate as scavenger for aromatic amine and

(b) a hydrophilic urethane prepolymer having polyether units of which at least 40 mole per cent are oxyethylene units capped with an aromatic poly-isocyanate, the amount of aliphatic isocyanate in said mixture being not more than 8 parts by weight based on the weight of the functional groups of the scavenger per 100 parts by weight of said prepolymer.

16. A composition according to claim 15 in which the urethane prepolymer is the reaction product of a mixture of a polyoxyethylene polyol with an aliphatic alcohol having at least 3 hydroxyl groups per molecule, said hydroxyl groups being capped with an aromatic poly-isocyanate.

17. A composition according to claim 16 in which the polyoxyethylene polyol is a polyethylene glycol and the aliphatic alcohol has 3 hydroxyl groups per molecule.

18. A composition according to any one of claims 15 to

17 in which the aliphatic isocyanate is 4,4'-methylene-biscyclohexyl diisocyanate, isophorone diisocyanate, bis(3-methyl-4-isocyanatocyclohexyl)methane, tris(6-isocyanatohexamethylene)-biuret or an isocyanate derivative of a condensed fatty acid.

19. A composition according to any one of claims 15 to

18 in which the aliphatic isocyanate is present in an amount from 0.1 to 4% by weight of said prepolymer.

20. A composition according to claim 15 substantially as hereinbefore described.

DATED THIS 3>C DAY OF

AGENTS TOR THE APPLICANTS

185278

< K^7r

WHAT WE CLAIM IS:

1. A process for preparing a fluid-perrnearole (as hereinbefore defined) polyurethane foam derived from an argmatic poly-isocy^riats which comprises incorporating a scavenger fojc aromatic amine either in:

(a) a mixture of aromatic poly-isocyanate, a polyether or polyester polyol and water in which ca^e the index of safid scavenger in the mixture is from 0.01 to /i and the index hf. said aromatic poly-isocyanate in the mixture is from 110 Lo 96, or

(b) a mixture of a prepolymer comprising po/yether or polyester units capped by an aromatic poly-isocy/nate, and water, in which case the scavenger is present in an amounrt not more than 8 parts by weight based on thar weight of the functional groups of the scavenger per 100 parts bv/weight, of said nrepolymer, and causing the resulting mixture tcy react, or in (c)/the foam obtained by reacting a mixture as jfief.ined. under (a)/or (b), which mixture need not contain scavenge)

2. A proces/ according to cl/ira 1 in which the scavenger

-2

exhibits a reaction rate with vatat which, is less than 10 txraes the reaction rate of the aromatic poly-isocyanate with water.

3. A npocess according po claim 2 in which the scavenger is an aliph/cic isocyanate

U. /h process accordi&g to claim 3 in which the aliphatic isocyanarce is '-i, 4 ' -methy^nebiscyclohexyl diisocyanate , iso-phoroiye diisocyanate , ms ( 3-inethyl- ^-isocyanatocyclohexyl) me thane , tris^6-isocyanatohexa/ethylene)- biuret or an isocyanate derivative of/a condensed fatt/ acid.

--

IB J UN 1979

- 32

WHAT WE CLAIM IS:

1. A process for preparing a fluid-permeable (as hereinbefore defined polyurethane foam derived from an aromatic poly-isocyanate which comprises incorporating a scavenger /or aromatic amine which is a mono- or poly-aliphatic isocyanate either in:

(a) a mixture of aromatic poly-isocyanate, df polyether or polyester polyol and water in which cAse the index of said scavenger in the mixture is from 0.01 to & and the /ndex of said aromatic poly-isocyanate in the mixture is mrom 110 to 96, or

(b) a mixture of a prepolymer comprising polyether or polyester units capped by an a/omatic po/y-isocyanate, and water,

in which case the scavenger i/s present/in an amount not more than 8

parts by weight based on tlye weight o£ the functional groups of,

the scavenger per 100 par/s by weigjat of said prepolymer, and causing the resulting mixture to yeact, or in (c) the foam obtained by reacting a mixtureyas definecy under (a) or (b), which mixture need not contain scavenger.

2. A process/according/to claim 1 in which the scavenger

«-2

exhibits a. react iron rate wijth water which is less than 10 ~ times the reaction ^ate of the/aromatic poly-isocyanate with water.

3. A process acco^ing to claim 1 or 2 in which the aliphatic isocyanate /s 4,4'-metftylenebiscyclohexyl diisocyanate, isophorone din.socyanate/ bis (3-methyl-4-isocyanatocyclohexyl)methane, tris(6-Lsocyanatohexamethylene)-biuret or an isocyanate derivative

/

of a condensed fa/tty acid.

/

A process according to any one of the preceding claims /

in ,which the foam is dried after preparation.

&

T-

tj,

rn\

-32-

AMENDED

(%<<?■ iy

5. A process according to any one of £he preceding claims in which the foam is dried after preparation.

6. A process according to any one y6f the preceding/clairns for preparing a hydrophilic polyurethane foam.

7. A process according to any c/ne of the preced/ng claims in which the scavenger is incorporated into a mixture/ as defined under (b).

A process according to ^laim 7 in which/the scavenger

/ , -3

exhibits a reaction rate with water which is lesp than 10 times the reaction rate of the aromatic polyisocyanei/e with water.

9. 7\ process according to claim 7 or in which the urethane prepolymer is the reaction/product of a polyoxyalkylene ' polyol wherein at least kO mole f/o of the oxyalkylene units are oxyethylene and an arom/tic polyisocyan^e.

10. A process according to claim 9 in which at least 60 mole % of the oxyal'k/lene units are occy ethylene.

11. A process according to amy ^ of claims 7 to 10 in which the urebnane prepolymer ys the reaction product of a' polyoxvethylene/polyol with a ffionomeric alcohol having at least 3 hydroxyl groups per molecule/ capped with an aromatic poly-isocyanfete.

12. /a process accord/ng to claim 11 in whih the alcohol is an aliphatic alcohol having 3 hydroxyl groups per molecule and the/polyol is a poly^6>:yethylene glycol.

.3. A process according to any one of claims 3 to 12

in vj^iich the aliphatic isocyanate is present in an amount from to h% by weight/of said prepolymer.

1*K A process according to any one of claims 7 to 13 in which

1000

rthe water is present in an amount from 0ch to/ mcle J^O/mole of NCO groups.

15. A process according to anv one of claims 7 to 1U in.

[NOW amended;

1 8W

5. A process according to any one of the preceding claims for preparing a hydrophilic polyurethane foam.

/ r

6. A process according to any one of the preceding claims in which the scavenger is incorporated into a mixture as defined under (b) .

7. A process according to c/laim 6 in wh^ch the scavenger

-3

exhibits a reaction rate with water which is/less than 10 times the reaction rate of the aromatic polyisocyanate with water.

8. A process according ato claim 6 ojc 7 in which the urethane prepolymer is the reaction product of a /polyoxyalkylene polyol wherein at least 40 mole %/ of the oxyalkylene units are oxyethylene and an aromai/ic polyisocyanate.

/ /

9. A process according to cla/m 8 m which at least 60 mole % of the oxyalkylene units ar/e oxy ethylene.

10. A process according to any of claims 6 to 9 in which the uretha/ne prepolymer is the reaction product of a polyoxyethylene polyol with a/monomeric alcohol having at least 3 hydroxyl groups per molecv^&e, capped with an aromatic poly-isocyanate^.

11. A process according to claim 10 in which the alcohol is an aliphatic alcohols/having 3 hydroxyl groups per molecule and the po/lyol is a polyoxyethylene glycol.

12. Ja process according to any one of the preceding claims in which the aliphatic isocyanate is present in an amount from

/

0.1 to; 4% by weight of said prepolymer.

13. A process according to any one of claims 6 to 12 in

/

which the water is present in an amount from 0.4 to 1000 mole

/, /

H2p/mole of NjPO groups.

/

14. A process according to any one of claims 6 to 13 in

6 JUL 1982

*/

-33-

/f MS uii78-

kwhich the water is present in an amount from 6.5 to 390 mole ^0/

mole of NCO groups.

16. A process according to any one of claim£ 1 to 6 in whL6h the scavenger is incorporated into a mixture as Refined under (f) .

17. A process according to claim 16 in y/hich the polyoj is a polyether.

18. A process according to claim 17 /in which the po/yol is a hydrophilic polyether.

19. A process according to claim/18 in which the/polyol is a polyoxyalkylene polyol in which at le^st 40 mole % of/the oxyalkylene units are oxyethylene.

20. A process according to dlaim 19 in whic/i at least 60 mole % of the oxyalkylene units aire oxyethylene.

21. A process according k,o any one of cl4ims 18 to 20 in which the polyether is a reaction product of a polyoxyethylene polyol with an aliphatic alcohol halving at least 3y4iydroxyl groups per molecule,

22. A process according to claim If/ in which the polyol is a polyester.

23. A process a/cording to any </ne of claims 16 to 21 in which the water is p/esent in an amoijrit from 0.40 to 0.55 mole H^O/mole of NCO grg/ups .

24. A process according to/any one of claims 16 to ,22 in which the water is present in an amount, from 6.5 to 390 mole H^O/mole of NCO groups

25. A^process accordii^ to any one of claims 16 to 23 in which the /ndex of the aromatic poly-isocyanate in the mixture is from 9 9.y to 96.

A process according to claim 1 substantially as herei/before described/

27. A process/according to claim 1 substantiall^pRA^^cribed in7 any one of Examm.es 1 to 4 and 6 to 25.

- 34 -

which the Water is present in an amount from 6.5 to

0

mole of NCO groups. \

mole t^O/

15. a process according to any one ol claims 1 to 5 in which the scavenger is incorporated into a mixture as defined under (a).

/

16. a process according to claim 1 p in w^iich the polyol is a polyether. / /

/

17. A process according to claim- 16 in/which the polyol is a hydrophilic polyether,

./ /

18. A process according to claim 17 in which the polyol is a s

r polyoxyalkylene polyol in which at. l^ast 40 mole % of the oxyalkylene units are oxyethylene. j, J

19 . A process according to claim £8 in which at least 60

■ ' / /

mole % of the oxyalkylene units afe oxyethylene.

• '' f

20. A process according to any one of claims 17 to 19 in which the polyether is a reaction product of a polyoxyethylene polyol

. / /

with an aliphatic alcohol having at least 3 hydroxyl groups per molecule.

/' /

21 a process according to cjLaim 15 in which the polyol is a polyester.

22. A process accord/ng to/any one of claims 15 to 20 in which the water is present/in an,/amount from 0.40 to 0.55 mole I^O/mole of NCO groups,

23. A process ac^'rding^to any one of claims 15 to 21 in which the water is present in/an amount from 6.5 to 390 mole I^O/mole u >i of NCO groups.

24. A process According to any one of claims 15 to 22 in which the index of trie aromatic poly-isocyanate in the mixture is from 99.8 to 96.

%%> • A process according to claim 1 substantially as hereinbefore described.,

i!

26. a process according to claim 1 substantially as described

/ h in'M^&one of Examples' 1 to 4 and 6 to 25.

/ ' //

NOW AMENDED'

- 34 -

©W AMENDED

185278

i *<*71r

28. A fluid-permeable polyurethane ioara whenever prepared by a process as claimed in any one 9/f the preceding claims.

29. A composition for prepariiyg a polyurethanj foam comprising:

(a) an aliphatic isocyanat^ as scavenger f^r aromatic amine and

(b) a hydrophilic urethane prepolymer hAving polyether backbone segments cappera. with an aromapc poly-isocyanate, the amount of aliphatic isocyaniate in said mixtyure being not more than 8 parts by weight barsed on the weigj/t of the functional groups of the scavenger per A.00 parts by weLght of said prepolymer.

30. A composit/on according to/claim 29 in which the urethane prepolymerAs the reaction/product of a mixture of a polyoxyethylene raplyol with an a^hatic alcohol having at least 3 hydroxyl groups per molecyle, said hydroxyl groups being capped with an aromatic poly-/socyanate.

31. H composition according to claim 30 in which the polyoxyethylene polyol is A polyethylene glycol and the aliphatic aldohol has 3 hydrgocyl groups per molecule.

[2. A composition according to any one of claims 29 to 31/in which the al/phatic isocyanate is 4,k1-methylene-biscyc^ohexyl diisocyanate, isophorone diisocyanate , bis( 3^-methyl-4-isocyanatocyclohexyl )methane , tris ( 6-isoeyanatohexamethy/ene)-biuret or an isocyanate derivative of] a condensed fatirty acid.

- 35

N.Z. PATENT OFFICE

2 2 AUG 1979

1

27. A fluid-permeable polyuretKarre—fo-am-whlenever prepared by a process as claimed in any one of- the

..preceding, claims..

/ f

/

28. A composition for preparing /a polyurethane foam comprising:

/

(a) an aliphatic isocyanate as scavenger for aromatic

(b) a hydrophilic /urethane Prepolymer having amine and polyether backbone segments/capped with an aromatic poly-isocyanate,

■P !

the amount of aliphatic isocyanate /n said mixture being not

,7

/ /

more than 8 parts by weight based on the weight of the functional groups of the scavenger/per 100 a4rts by weight of said prepolymer.'

— ^29. 'AT c~ompos*il:ion^adcbrding~t6^~cTaiiTr'23 "Tn whicfi the urethane prepolymer is the reaction product of a mixture of a polyoxyethylene polyol with an aliphatic alcohol having at least 3 hydroxyl groups yper molecule, said hydroxyl groups being capped wii^i an arom^zic poly-isocyanate.

30 J A composition according to claim 29. in which the polyoxyefthylene polyol is a polyethylene glycol and the aliphatic alcohol hasp 3 hydroxyl groups per molecule.

31. A composition according to any one of claims 28 to fo in which/the aliphatic isocyanate is 4,4'-methylene-biscyplohexyl diisocyanate, isophorone diisocyanate, bis(B-methyl-4yisocyanatocyclohexyl)methane, tris(6-isocyanatohexamethylene)-biuret or an isocyanate derivative loJL a condensed fatty acid.

:26JllL i%2

- 35 -

4.

% i.

,«iO

t £-1*

33. a composition /according to atfy one of claims 29 to .32 in which the alijgKatic isocyanajre is present in an amount from 0.1 to 4% by weight of sai/6 prepolymer.

34. A composition according to claim 2 9 substantially a$r hereinbefore ^described.

DATED DAY OF ^7*]

A, J. PARK & SON

PER ^ O

AGENTS FOR THE APPLICANTS

- 36 -

N.Z. PATENT 0FFIC&

2 2 AUG 1979|

1 :'f \Vl

i§§2 m m

32. A composition according to any one of claims 28 to 31 in which the aliphatic/isocyanate present in an amount from 0.1 to 4% by weight of said prepolymer.

I

33. A composition according tc^ claim 28

substantially as hereinbefore described.

DATED THIS DAY OF

A. J. PA R/K & SON

PER

AGENTS FOP, THE APPLICANTS

AM EXU"-D |

i982

- 36 -