WO2007111828A2

WO2007111828A2 - Low density, natural oil based polyurethane foam without silicone based cell stabilizing additive

Info

Publication number: WO2007111828A2
Application number: PCT/US2007/006187
Authority: WO
Inventors: Jean-Marie Sonney; Francois M. Casati
Original assignee: Dow Global Technologies Inc.
Priority date: 2006-03-23
Filing date: 2007-03-09
Publication date: 2007-10-04
Also published as: WO2007111828A3

Abstract

The present invention pertains to natural oil based polyols and to their use in the production of toluene diisocyanate (TDI) based, low density, flexible, one-shot polyurethane foams. The foams are produced from formulations where the natural oil based polyol comprises at least 20 weight percent of the polyol component and the foams are produced in the absence of a cell-stabilizing silicone surfactant.

Description

LOW DENSITY, NATURAL OIL BASED POLYURETHANE FOAM WITHOUT SILICONE

BASED CELL STABILIZING ADDITIVE

The present invention pertains to natural oil based polyols and to their use in the production of toluene diisocyanate (TDI) based, low density, flexible polyurethane foams.

Polyether polyols based on the polymerization of alkylene oxides, and/or polyester polyols, and/or combinations thereof, are the major components of a polyurethane system together with isocyanates. Polyols can also be filled polyols, such as SAN (Styrene/Acrylonitrile) , PIPA (polyisocyanate polyaddition) or PHD (polyurea) polyols, as described in "Polyurethane Handbook", by G. Oertel, Hanser publisher.

One class of polyols are those made from vegetable oils or ^• renewable feedstocks. Such polyols are described by Peerman et al . in U.S. Patents 4,423,162; 4,496,487 and 4,543,369. Peerman et al . describe hydroformylating and reducing esters of fatty acids as are obtained from vegetable oils and forming esters of the resulting hydroxylate materials with a polyol or polyamine. Higher functional polyester polyol materials derived from fatty acids are described in WO 2004/096882; WO 2004/096883. These polyester polyols are made by reacting a polyhydroxyl initiator with certain hydroxymethylated fatty acids . Others approaches for polyols based on renewable resources are described for example in Publications WO 2004/020497; WO 2004/099227; WO 2005/0176839; WO 2005/0070620 and in US Patent 4,640,801.

Polyurethane foams generally contain additional components such as surfactants, stabilizers, cell regulators, antioxidants, cross-linkers and/or chain extenders, as well as catalysts, such as tertiary amines and/or organometallic salts and depending on the end use application, flame retardant additives and/or fillers.

As a number of the materials and additives used in producing polyurethane foam can be released as volatile organic compounds (VOCs) , efforts have been made to utilize additives which reduce the level of VOCs. For example, efforts have been made to reduce the level of volatile amine catalysts by utilizing amine catalysts which contain a hydrogen isocyanate reactive group, i.e. a hydroxyl or a primary and/or a secondary amine. Such catalysts are disclosed in EP 747,407. Other types of reactive monol catalysts are described in U.S. Patents 4,122,038, 4,368,278 and 4,510,269. Use of specific amine-initiated polyols is proposed in EP 539,819, in U.S. Patent 5,672,636 and in WO 01/ 58,976. Polyols containing tertiary amino groups are described in US 3,428,708, in US 5,482,979, and in US 4,934,579.

Another example for the reduction of VOCs is the replacement of the antioxidant BHT (Butylated Hydroxy-Toluene) with less migrating molecules such as those disclosed in EP 1,437,372.

While all of these technologies allow elimination of some VOCs from polyurethane flexible foams, surfactant used to stabilize foam cells may also contribute to the level of VOCs in the foam. Accordingly it would be desirable to provide a flexible polyurethane foam having good properties that are made from a polyol based on a renewable resource and which further aids in the goal of reducing the level of VOCs in the foam.

In addition, polyurethane materials produced using a substantial amount of the polyol from a renewable resource in the polyol formulation have a tendency to have low air flow values, see for example, WO 2004/096883. The low air flow values indicate the foams are not well suited for such uses as automotive seating as poor airflow negatively influences resistance to dynamic fatigue. Furthermore, foams produced using high levels of materials from natural resources in the formulation have been shown to have poorer compression set values, see for example, U.S. Publication 2005/007620.

It is an object of the present invention to produce commercially viable, low density, flexible polyurethane foams, with open cells having good foam properties, such as, low compression sets and good resistance to dynamic fatigue, based on natural oil based polyol (NOBP) which are capable of meeting OEM' s (Original Equipment Manufacturers) specifications.

It is a further object the present invention to produce free-rise (slabstock) or molded, low density, flexible polyurethane foams based on NOBP without the use of a silicone based cell stabilizing surfactant or with a substantial reduction in levels of such surfactants.

The present invention is a process for the production of a flexible polyurethane foam by reaction of a mixture of (a) an isocyanate component containing at least 60 weight percent TDI ;

(b) a polyol composition comprising

(bl) up to 80 percent by weight of at least one polyol compound having a nominal starter functionality of 2 to 8 and a hydroxyl number from 15 to 200, and

(b2) from 20 to 100 percent by weight of at least one natural oil based polyol with a hydroxyl number below 300 and a viscosity below 6,000 mPa.s measured at 25°C;

(c) in the presence of 0.01 to 1.5 parts by weight of polyol of a cell regulating agent;

(d) in the presence of 0.5 to 10 parts by weight of polyol of water as blowing agent; and

(e) optionally additives or auxiliary agents known per se for the production of polyurethane foams; wherein the total mixture contains substantially no silicone based cell stabilizing surfactant.

In another embodiment, the present invention is a flexible polyurethane foam, having a density below 50 kg/m³, which is the reaction product of an isocyanate component containing at least 60 percent by weight of TDI and a polyol component comprising (i) up to 80 percent by weight of the total polyol of at least one polyol compound other than (ii) having a nominal starter functionality of 2 to 8 and a hydroxyl number from 15 to 200;

(ii) from 20 to 100 percent by weight of the total polyol of at least one natural oil based polyol with a hydroxyl number below 300 and a viscosity below 6,000 mPa.s;

(iii) from 0.01 to 1.5 parts by weight of polyol of a cell regu1ating agent ;

(iv) from 0.5 to 10 parts water as blowing agent; and

(v) optionally additives or auxiliary agents known per se for the production of polyurethane foams; wherein the total mixture contains substantially no silicone based cell stabilizing surfactant.

In another embodiment, the present invention is a process whereby polyol (bl) is totally or partially amine based, i.e. contains nitrogen in the starter or in the chain and preferably has autocatalytic characteristics for the polyurethane reaction.

In another embodiment, the present invention is a process whereby polyol (bl) and/or (b2) contain primary and/or secondary hydroxyl groups .

In another embodiment, the present invention is a process whereby polyol (bl) and/or (b2) contains primary and/or secondary amine groups .

The polyol (b2) based on renewable resources is referred to herein as natural oil based polyols (NOBP) . The polyols (b2) are liquid at room temperature and have multiple active sites. The addition of polyol (b2) to a one-shot polyurethane reaction mixture eliminates the need to include a silicone based cell stabilizing surfactant in a flexible, and/or viscoelastic foam formulation. As used herein, substantially no silicone based cell stabilizing surfactant means the absence of a silicone based cell stabilizing surfactant or a level of such surfactant below detectable changes in the foam property measured against the properties of the foam prepared in the absence of a silicone based surfactant.

It has been unexpectedly found polyurethane foams, particularly HR and molded foam, can be produced using in the polyol component 20 percent by weight or more of a NOBP to obtain foam wherein the foam has sufficient open cell structure such that comparable to conventional formulations based on polyols from petroleum based feedstocks the foam has air flow properties and compression set properties comparable to conventional formulations based on polyols from petroleum based feedstocks. Such foams are produced by omitting from the formulation a silicone based cell stabilizing surfactant, or a substantial reduction in the amount of such surfactants in the formulation, however; the formulation does include the presence of a cell regulating agent.

For acceptable air flow properties, the air flow is generally at least 2.5 cfm as measured by ASTM 3574-95. Preferably the air flow is 3.0 cfm or greater. More preferably the air flow is 3.5 cfm or greater. For acceptable compression set (CS), the foam has a 75 % CS value of 20 % CD or less as measured by OPEL 60283-4-96. Preferably the foam has a CS of less than 18 percent. More preferably the foam has a CS of less than 15 percent. (CD is a means of calculating the CS, i.e., dividing by the sample thickness loss by the thickness of the sample under compression. For instance a 50 % CS is divided by 0.5 x original thickness, and a 75 % CS is divided by 0.75 X the original thickness.)

As the silicone based stabilizing can be omitted or the level substantial reduced, the present invention provides for polyurethane products containing reduced levels of VOCs. A further reduction in the level of VOCs can also be achieved by replacing, or partial replacement of fugitive amine catalysts generally used in the production of polyurethane foam with an autocatalytic polyol as described herein.

As used herein the term polyols are those materials having at least one group containing an active hydrogen atom capable of undergoing reaction with an isocyanate. Preferred among such compounds are materials having at least two hydroxyls, primary or secondary, or at least two amines, primary or secondary, carboxylic acid, or thiol groups per molecule. Compounds having at least two hydroxyl groups or at least two amine groups per molecule are especially preferred due to their desirable reactivity with polyisocyanates .

Suitable polyols (bl) of the present invention are well known in the art and include those described herein and any other commercially available polyol and/or SAN, PIPA or PHD copolymer polyols. Such polyols are described in "Polyurethane Handbook", by G. Oertel, Hanser publishers. Mixtures of one or more polyols and/or one or more copolymer polyols may also be used to produce polyurethane products according to the present invention.

Representative polyols include polyether polyols, polyester polyols, polyhydroxy-terminated acetal resins, hydroxyl- terminated amines and polyamines . Examples of these and other suitable isocyanate-reactive materials are described more fully in U.S. Patent 4,394,491. Alternative polyols that may be used include polyalkylene carbonate-based polyols and polyphosphate- based polyols. Preferred are polyols prepared by adding an alkylene oxide, such as ethylene oxide, propylene oxide, butylene oxide or a combination thereof, to an initiator having from 2 to 8, preferably 2 to 6 active hydrogen atoms. Catalysis for this polymerization can be either anionic or cationic, with catalysts such as KOH, CsOH, boron trifluoride, or a double cyanide complex (DMC) catalyst such as zinc hexacyanocobaltate or quaternary phosphazenium compound.

Examples of suitable initiator molecules are water, organic dicarboxylic acids, such as succinic acid, adipic acid, phthalic acid and terephthalic acid; and polyhydric, in particular dihydric to octohydric alcohols or dialkylene glycols.

Exemplary polyol initiators include, for example, ethanediol , 1,2- and 1 , 3-propanediol , diethylene glycol, dipropylene glycol, 1, 4-butanediol , 1, 6-hexanediol, glycerol, pentaerythritol , sorbitol, sucrose, neopentylglycol ; 1,2-propylene glycol; trimethylolpropane glycerol; 1, 6-hexanediol; 2,5- hexanediol; 1 , 4 -butanediol ; 1, 4-cyclohexane diol; ethylene glycol; diethylene glycol; triethylene glycol; 9(1)- hydroxymethyloctadecanol , 1, 4-bishydroxymethylcyclohexane; 8,8- bis (hydroxymethyl) tricyclo [5, 2, 1, O²'⁶] decene; Dimerol alcohol (36 carbon diol available from Henkel Corporation) ; hydrogenated bisphenol,- 9, 9 (10, 10) -bishydroxymethyloctadecanol ; 1,2,6- hexanetriol; and combination thereof.

Other initiators include linear and cyclic compounds containing an amine. Exemplary polyamine initiators include ethylene diamine, neopentyldiamine, 1, 6-diaminohexane,- bisaminomethyltricyclodecane; bisaminocyclohexane,- diethylene triamine,- bis-3-aminopropyl methylamine; triethylene tetramine various isomers of toluene diamine; diphenylmethane diamine; N- methyl-1, 2-ethanediamine, N-Methyl-1, 3-propanediamine, N, N- dimethyl-1, 3-diaminopropane, N,N-dimethylethanolamine, 3,3'- diamino-N-methyldipropylamine, N, N-dimethyldipropylenetriamine , aminopropyl-imidazole .

Exemplary aminoalcohols include ethanolamine , diethanolamine, and triethanolamine.

Polyol (bl) can also contain a tertiary nitrogen in the chain, by using for instance an alkyl-aziridine as co-monomer with PO and EO.

Polyols with tertiary amine end-cappings are those which contain a tertiary amino group linked to at least one tip of a polyol chain. These tertiary amines can be N,N-dialkylamino, N- alkyl, aliphatic or cyclic, amines, polyamines.

Other useful initiators that may be used include polyols, polyamines or aminoalcohols described in U.S. Patents 4,216,344; 4,243,818 and 4,348,543 and British Patent 1,043,507.

Of particular interest are poly(propylene oxide) homopolymers , random copolymers of propylene oxide and ethylene oxide in which the poly(ethylene oxide) content is, for example, from about 1 to about 30% by weight, ethylene oxide-capped poly(propylene oxide) polymers and ethylene oxide-capped random copolymers of propylene oxide and ethylene oxide. For slabstock foam applications, such polyetherε preferably contain 2-5, especially 2-4, and preferably 2-3, mainly secondary hydroxyl groups per molecule and have an equivalent weight per hydroxyl group of from about 400 to about 3000, especially from about 800 to about 1750. For high resiliency slabstock and molded foam applications, such polyethers preferably contain 2-6, especially 2- 4, and in some applications preferably 2-5, mainly primary hydroxyl groups per molecule and have an equivalent weight per hydroxyl group of from about 1000 to about 3000, especially from about 1200 to about 2000. When blends of polyols are used, the nominal average functionality (number of hydroxyl groups per molecule) will be preferably in the ranges specified.

For viscoelastic foams shorter chain polyols with hydroxyl numbers above 150 are also used.

The polyether polyols may contain low terminal unsaturation (for example, less that 0.02 meq/g or less than 0.01 meq/g) , such as those made using so-called double metal cyanide (DMC) catalysts, as described for example in US Patent Nos . 3,278,457, 3,278,458, 3,278,459, 3,404,109, 3,427,256, 3,427,334, 3,427,335, 5,470,813 and 5,627,120. Polyester polyols typically contain about 2 hydroxyl groups per molecule and have an equivalent weight per hydroxyl group of about 400-1500. Polymer polyols of various sorts may be used as well. Polymer polyols include dispersions of polymer particles, such as polyurea, polyurethane- urea, polystyrene, polyacrylonitrile and polystyrene-co- acrylonitrile polymer particles in a polyol, typically a polyether polyol . Suitable polymer polyols are described in US Patent Nos . 4,581,418 and 4,574,137.

In one embodiment, (bl) contains at least one polyol which contains autocatalytic activity and can replace a portion or all of the amine and/or organometallic catalyst generally used in the production of polyurethane foams. Autocatalytic polyols are those made from an initiator containing a tertiary amine, polyols containing a tertiary amine group in the polyol chain or a polyol partially capped with a tertiary amine group. Generally, (b2) is added to replace at least 10 percent by weight of amine catalyst while maintaining the same reaction profile. Generally an autocatalytic polyol is added to replace at least 20 percent by weight of the conventional amine catalyst while maintaining the same reaction profile. More preferably is added to replace at least 30 percent by weight of the amine catalyst while maintaining the same reaction profile. Such autocatalytic polyols may also be added to replace at least 50 percent by weight of the amine catalyst while maintaining the same reaction profile. Alternatively, such autocatalytic polyols may be added to enhance the demold time.

Such autocatalytic polyols are disclosed in EP 539,819, in U.S. Patents 5,672,636; 3,428,708; 5,482,979; 4,934,579 and 5,476,969 and in WO 01/ 58,976, the disclosure of which is incorporated herein by reference.

In one preferred embodiment, the autocatalytic polyol has a molecular weight of from about 1000 to about 12,000 and is prepared by alkoxylation of at least one initiator molecule of the formula

H_nA-(CHa)_n-N(R)-(CH₂)_P-AH_n, Formula (I) wherein n and p are independently integers from 2 to 6,

A at each occurrence is independently oxygen, nitrogen, sulfur or hydrogen, with the proviso that only one of A can be hydrogen at one time,

R is a C₁ to C₃ alkyl group, m is equal to 0 when A is hydrogen, is 1 when A is oxygen and is 2 when A is nitrogen, or H₂N- (CH₂) _m-N- (R) -H Formula (II) where m is an integer from 2 to 12 and R is a C₁ to C₃ alkyl group.

Preferred initiators for the production of an autocatalytic polyol include, 3 , 3 ' -diamino-N-methyldipropylamine, 2,2' -diamino-N-methyldiethylamine , 2 , 3-diamino-N-methyl-ethyl- propylamine N-methyl-1 , 2-ethanediamine and N-methyl-1, 3- propanediamine .

Generally when used, the aforementioned autocatalytic polyols will constitute up to 50 weight percent of the total polyol, preferably up to 40 weight percent of the polyol. Generally when used, such autocatalytic polyols will constitute at least 1 weight percent of the polyol. More preferably such polyols will represent 5 percent of greater of the total polyol.

Autocatalytic polyols containing at least one imine linkage and one tertiary amine group as disclosed in WO Publication 2005063840, the disclosure of which is incorporated herein by reference may also be used. In general such polyols are based on the reaction between an aldehyde, or a ketone, and a molecule containing both primary amine and tertiary amine groups. When such imine based polyols are used, they will generally constitute from 0.5 to 2 parts of the polyol component. A combination of the autocatalytic polyols may also be used.

Polyols of (b2) are polyols based on or derived from renewable resources such as natural and/or genetically modified (GMO) plant vegetable seed oils and/or animal source fats. Such oils and/or fats are generally comprised of triglycerides, that is, fatty acids linked together with glycerol. Preferred are vegetable oils that have at least about 70 percent unsaturated fatty acids in the triglyceride. Preferably the natural product contains at least about 85 percent by weight unsaturated fatty acids. Examples of preferred vegetable oils include, for example, those from castor, soybean, olive, peanut, rapeseed, corn, sesame, cotton, canola, safflower, linseed, palm, sunflower seed oils, or a combination thereof. Examples of animal products include lard, beef tallow, fish oils and mixtures thereof. A combination of vegetable and animal based oils/fats may also be used. The iodine value of these natural oils range from about 40 to 240. Preferably polyols (b2) are derived from soybean and/or castor and/or canola oils.

For use in the production of flexible polyurethane foam it is generally desirable to modify the natural materials to give the material isocyanate reactive groups or to increase the number of isocyanate reactive groups on the material. Preferably such reactive groups are a hydroxyl group. Several chemistries can be used to prepare the polyols of (b2) . Such modifications of a renewable resource include, for example, epoxidation, as described in US Patent 6,107,433 or in US Patent 6,121,398; hydroxylation, such as described in WO 2003/029182; esterification such as described in US 6,897,283; 6,962,636 or 6,979,477,- hydroformylation as described in WO 2004/096744; grafting such as described in US 4,640,801; or alkoxylation as described in US 4,534,907 or in WO 2004/020497. The above cited references for modifying the natural products are incorporated herein by reference. After the production of such polyols by modification of the natural oils, the modified products may be further alkoxylated. The use of EO or mixtures of EO with other oxides, introduce hydrophilic moieties into the polyol . In one embodiment, the modified product undergoes alkoxylation with sufficient EO to produce a polyol (b2) with from 10 to 60 weight percent EO; preferably 20 to 40 weight percent EO.

In another embodiment, the polyols (b2) are obtained by a combination of the above modification techniques as disclosed in PCT Publications WO 2004/096882 and 2004/096883, and Applicant's copending application Serial No. 60/676,348 entitled "Polyester Polyols Containing Secondary alcohol Groups and Their Use in Making Polyurethanes Such as Flexible Polyurethane Foams", the disclosures of which are incorporated herein by reference. In brief, the process involves a multi-step process wherein the animal or vegetable oils/fats is subjected to transesterification and the constituent fatty acids recovered. This step is followed by hydroformylating carbon-carbon double bonds in the constituent fatty acids to form hydroxymethyl groups, and then forming a polyester or polyether/polyester by reaction of the hydroxymethylated fatty acid with an appropriate initiator compound. This later technologies is favored since as it allows the production of a polyol (b2) with both hydrophobic and hydrophilic moieties. The hydrophobic moiety is provided by the natural oils since those contain C4 to C24 saturated and/or unsaturated chain lengths, preferably C8 to Cl8 chain lengths, while the hydrophilic moiety is obtained by the use of proper polyol chains present on the initiator, such as those containing high levels of ethylene oxide.

The initiator for use in the multi-step process for the production of polyol (b2) may be any of the initiators given above used in the production of polyol (bl) .

Preferably the initiator is selected from the group consisting of neopentylglycol ,- 1 , 2-propylene glycol; trimethylolpropane ; pentaerythritol ; sorbitol; sucrose; glycerol; diethanolamine,- alkanediols such as 1, 6-hexanediol , 1, 4-butanediol ; 1, 4-cyclohexane diol; 2, 5-hexanediol,- ethylene glycol; diethylene glycol, triethylene glycol; bis-3-aπιinopropyl methylamine,- ethylene diamine; diethylene triamine,- 9 (1) -hydroxymethyloctadecanol, 1,4- bishydroxymethylcyclohexane; 8,8- bis (hydroxymethyl) tricyclo [5, 2, 1, 0^3S] decene; Dimerol alcohol; hydrogenated bisphenol,- 9,9(10,10) -bishydroxymethyloctadecanol; 1 , 2 , 6-hexanetriol and combination thereof.

More preferably the initiator is selected from the group consisting of glycerol; ethylene glycol; 1, 2-propylene glycol; trimethylolpropane; ethylene diamine; pentaerythritol; diethylene triamine; sorbitol; sucrose; or any of the aforementioned where at least one of the alcohol or amine groups present therein has been reacted with ethylene oxide, propylene oxide or mixture thereof; and combination thereof.

Most preferably the initiator is glycerol, trimethylopropane, pentaerythritol, sucrose, sorbitol, and/or mixture thereof .

In one preferred embodiment, such initiators are alkoxlyated with ethylene oxide or a mixture of ethylene and at least one other alkylene oxide to give an alkoxylated initiator with a molecular weight of 200 to 6000, especially from 400 to 2000. Preferably the alkoxylated initiator has a molecular weight from 500 to IOOO .

In one embodiment, polyol (b2) contains from 10 to 60 weight percent ethylene oxide. Preferably polyol (b2) will contain from 15 to 50 weight percent EO. More preferably polyol (b2) contains from 20 to 40 weight percent ethylene oxide.

The functionality of polyol (b2) , or blend of such polyols, is above 1.5 and generally not higher than 6. Preferably the functionality is below 4. The hydroxyl number of polyol (b2) , or blend of such polyols, is below 300 mg KOH/g, and preferably below 100.

The weight ratio of NOBP (b2) to polyol (bl) is adjusted to give foam stability without the need for a silicone based cell stabilizing surfactant. Usually the level of polyol (b2) is at least 20 PPHP (part per hundred parts polyol) in a foam formulation, and preferably at least 30 PPHP. More preferably (b2) is present in an amount of at least 40 PPHP. Polyol (b2) may constitute 75% or more, 85% or more, 90% or more, 95% or more or even 100% of the total weight of the polyol. The higher levels are particularly applicable for specific applications, such as high density, visco-elastic foams.

Combination of two types of polyols (b2) can also be used, either to maximize the level of seed oil in the foam formulation, or to optimize foam processing and/or specific foam characteristics, such as resistance to humid aging.

The viscosity of the polyol (b2) measured at 25°C is generally less than 6,000 mPa.s. Preferably the viscosity of polyol (b2) at 25°C is less than 5,000 mPa.s.

For producing flexible foams based on TDI and a level of at (least) 20 weight percent NOBP in the polyol formulation, giving good resiliency and other foam properties, a cell regulator is included in the reaction mix. Preferably the cell regulator is added in the polyol component .

Cell regulators have no bulk stabilization effect during foaming and act as antifoaming agents, see for example, Polyurethane Handbook, Gϋther Oertels ed. , 2^nd edition, page 108. Such regulators are generally low-molecular weight, low-viscosity organopolysiloxaneε as disclosed in U.S. Patent 4,042,540 and GB Patent 1 381 571 the disclosures of which are incorporated herein by reference. Preferred cell regulators are methylpolysiloxanes . It is unexpected these cell regulators would help in providing good foam properties with the composition of the present invention as these cell regulating surfactants are generally recommended for use in MDI based foams. Commercial examples of such products are Tegostab B 4113, Tegostab B 8715 LF, from Degussa, Niax L 3001 from GE Specialties, Dabco DC 2525 from Air Products. These cell regulating surfactants are generally added at less than 2 PPHP and preferably below 1.5 PPHP. More preferably the cell regulating agent is added at below 1 PPHP with the present invention. Generally the cell regulator is added in at least 0.01 PPHP and preferably at greater than 0.02 PPHP .

In the present invention, at least 60 percent of the reactivity isocyanate groups are from toluene 2,4- and/or 2,6- diisocyanate, referred to collective as TDI. Preferably TDI comprises at least 70 percent of the polyisocyanate. More preferably TDI comprises at least 80 percent of the polyisocyanate. In some embodiments, TDI is the sole isocyanate used for producing the polyurethane foam. When TDI does not constitute all of the isocyanate present, aliphatic, cycloaliphatic, arylaliphatic and other aromatic isocyanates may be used.

Examples of suitable additional aromatic isocyanates include the 4,4'-, 2,4' and 2,2' -isomers of diphenylmethane diisocyante (MDI) , blends thereof and polymeric and monomeric MDI blends, m- and p-phenylenediisocyanate, chlorophenylene-2 , 4- diisocyanate, diphenylene-4 , 4 ' -diisocyanate, 4, 4 ' -diisocyanate- 3,3' -ditnehtyldiphenyl , 3-methyldiphenyl-methane-4 , 4 ' -diisocyanate and diphenyletherdiisocyanate and 2, 4 , 6-triisocyanatotoluene and 2,4,4' -triisocyanatodiphenylether .

A crude polyisocyanate may also be used in the practice of this invention, such as crude toluene diisocyanate obtained by the phosgenation of a mixture of toluene diamine or the crude diphenylmethane diisocyanate obtained by the phosgenation of crude methylene diphenylamine . In one embodiment, TDI/MDI blends are used.

Examples of aliphatic polyisocyanates include ethylene diisocyanate, 1, 6-hexamethylene diisocyanate, isophorone diisocyanate, cyclohexane 1,4 -diisocyanate, 4,4'- dicyclohexylmethane diisocyanate, saturated analogues of the above mentioned aromatic isocyanates and mixtures thereof. The amount of polyisocyanate used in making the flexible foam is commonly expressed in terms of isocyanate index, i.e. 100 times the ratio of NCO groups to reactive hydrogens-contained in the reaction mixture. In the production of conventional slabstock foam, the isocyanate index typically ranges from about 75-140, especially from about 80 to 115. In molded and high resiliency slabstock foam, the isocyanate index typically ranges from about 50 to about 150, especially from about 75 to about 110.

For producing a polyurethane-based foam, a blowing agent is generally required. In the production of flexible polyurethane foams, water is preferred as a blowing agent. The amount of water is preferably in the range of from 0.5 to 10 parts by weight, more preferably from 2 to 7 parts by weight based on 100 parts by weight of the polyol. Carboxylic acids or salts are also used as reactive blowing agents. Other blowing agents can be liquid or gaseous carbon dioxide, methylene chloride, acetone, pentane, isopentane, methylal or dimethoxymethane, dimethylcarbonate. Use of artificially reduced or increased atmospheric pressure can also be contemplated with the present invention.

In addition to the foregoing critical components, it is often desirable to employ certain other ingredients in preparing polyurethane polymers. Among these additional ingredients are preservatives, flame retardants, colorants, antioxidants, reinforcing agents, fillers, including recycled polyurethane foam in form of powder.

One or more catalysts for the reaction of the polyol (and water, if present) with the polyisocyanate can be used. Any suitable urethane catalyst may be used, including tertiary amine compounds, amines with isocyanate reactive groups and organometallic compounds. Preferably the reaction is carried out in the absence of an amine or an organometallic catalyst or a reduced amount as described above. Exemplary tertiary amine compounds include triethylenediamine, N-methylmorpholine, N, N-dimethylcyclohexylamine , pentamethyldiethylenetriamine , tetramethylethylenediamine, bis (dimethylaminoethyl) ether, 1-methyl-4 -dimethylaminoethyl -piperazine , 3 -methoxy-N- dimethylpropylamine, N-ethylmorpholine, dimethylethanolamine, N-cocomorpholine, N,N-dimethyl-N' ,N¹ -dimethyl isopropylpropylenediamine, N,N-diethyl-3-diethylamino- propylamine and dimethylbenzylamine . Exemplary organometallic catalysts include organomercury, organolead, organoferric and organotin catalysts, with organotin catalysts being preferred among these. Suitable tin catalysts include stannous chloride, tin salts of carboxylic acids such as dibutyltin di-laurate, as well as other organometallic compounds such as are disclosed in U.S. Patent 2,846,408. A catalyst for the trimerization of polyisocyanates , resulting in a polyisocyanurate, such as an alkali metal alkoxide may also optionally be employed herein. The amount of amine catalysts can vary from 0.02 to 5 percent in the formulation or organometallic catalysts from 0.001 to 1 percent in the formulation can be used. In one preferred embodiment of the present invention, the foams are produced in the absence of a tin catalyst.

One or more crosslinkers may be present in the flexible foam formulation, in addition to the polyols (bl) and (b2) described above. This is particularly the case when making high resilience slabstock or molded foam. If used, suitable amounts of crosslinkers are from about 0.1 to about 1 part by weight, especially from about 0.25 to about 0.5 parts by weight, per 100 parts by weight of polyols.

For purposes of this invention "crosslinkers" are materials having three or more isocyanate-reactive groups per molecule and an equivalent weight per isocyanate-reactive group of less than 400. Crosslinkers preferably contain from 3-8, especially from 3-4 hydroxyl, primary amine or secondary amine groups per molecule and have an equivalent weight of from 30 to about 200, especially from 50-125. Examples of suitable crosslinkers include diethanol amine, monoethanol amine, triethanol amine, mono- di- or tri (isopropanol) amine, glycerine, trimethylol propane, pentaerythritol, sorbitol and the like.

It is also possible to use one or more chain extenders in the foam formulation. For purposes of this invention, a chain extender is a material having two isocyanate-reactive groups per molecule and an equivalent weight per isocyanate-reactive group of less than 400, especially from 31-125. The isocyanate reactive groups are preferably hydroxyl, primary aliphatic or aromatic amine or secondary aliphatic or aromatic amine groups. Representative chain extenders include amines ethylene glycol, diethylene glycol, 1, 2-propylene glycol, dipropylene glycol, tripropylene glycol, ethylene diamine, phenylene diamine, bis (3-chloro-4- aminophenyl) methane and 2 , 4-diamino-3 , 5-diethyl toluene. If used, chain extenders are typically present in an amount from about 1 to about 50, especially about 3 to about 25 parts by weight per 100 parts by weight of polyols.

The use of such crosslinkers and chain extenders is known in the art as disclosed in U.S. Patent 4,863,979 and EP Publication 0 549 120.

While the formulations do not include a silicone stabilizing surfactant, an emulsifier is generally added to help compatibilize the reaction components. Such emulsifiers are known in the art and examples of non silicone based emulsifier include sulfonated natural oils, fatty acid esters and ethylene oxide condensates of phenol or octylphenol . Examples of commercially available emulsifiers include Span 80, a sorbitan monooleate, and sodium salts of sulfonated ricinoleic acid. Another class of emulsifiers include the reaction product of an oc,ω-diol oligomer with a diisocyanate as disclosed in US Patent 5,057,573, the disclosure of which is incorporated herein by reference. When used, the emulsifier is generally from 0.1 to 10 weight percent of the total polyol , more preferably from 1 to 8 parts and even more preferably from 2 to 6 percent .

In utilizing the NOPB in the present invention, a polyether polyol may be included in the formulation, i.e, as part of polyol (bl) , to promote the formation of an open-celled or softened polyurethane foam. Such cell openers are disclosed in U.S. Patent 4, 863,976, the disclosure of which is incorporated here by reference. Such cell openers generally have a functionality of 2 to 12, preferably 3 to 8, and a molecular weight of at least 5,000 up to about 100,000. Such polyether polyols contains at least 50 weight percent oxyethylene units, and sufficient oxypropylene units to render it compatible with the components. The cell openers, when used, are generally present in an amount from 0.2 to 5, preferably from 0.2 to 3 parts by weight of the total polyol. Examples of commercially available cell openers are VORANOL*Polyol CP 1421 and VORANOL* Polyol 4053; VORANOL is a trademark of The Dow Chemical Company.

The applications for foams produced by the present invention are those known in the industry. Flexible and viscoelastic foams are mainly used in applications such as furniture and automobile seating. Other applications may include sun visors, steering wheels, packaging applications, armrests, door panels, noise insulation parts, other cushioning and energy management applications, carpet backing, dashboards and other applications for which conventional flexible polyurethane foams are used.

Processing for producing polyurethane products are well known in the art. In general components of the polyurethane- forming reaction mixture may be mixed together in any convenient manner, for example by using any of the mixing equipment described in the prior art for the purpose such as described in "Polyurethane Handbook", by G. Oertel, Hanser publisher.

In general, the polyurethane foam is prepared by mixing the polyisocyanate and polyol composition in the presence of the blowing agent, catalyst (s) and other optional ingredients as desired, under conditions such that the polyisocyanate and polyol composition react to form a polyurethane and/or polyurea polymer while the blowing agent generates a gas that expands the reacting mixture. The foam may be formed by the so-called prepolymer method, as described in U.S. Pat. No. 4,390,645, for example, in which a stoichiometric excess of the polyisocyanate is first reacted with the high equivalent weight polyol (s) to form a prepolymer, which is in a second step reacted with a chain extender and/or water to form the desired foam. Frothing methods, as described in U.S. Patents 3,755,212; 3,849,156 and 3,821,130, for example, are also suitable. So-called one-shot methods, such as described in U.S. Patent 2,866,744, are preferred. In such one- shot methods, the polyisocyanate and all polyisocyanate-reactive components are simultaneously brought together and caused to react. Three widely used one-shot methods which are suitable for use in this invention include slabstock foam processes, high resiliency slabstock foam processes, and molded foam methods. Slabstock foam is conveniently prepared by mixing the foam ingredients and dispensing them into a trough or other region where the reaction mixture reacts, rises freely against the atmosphere (sometimes under a film or other flexible covering) and. cures. In common commercial scale slabstock foam production, the foam ingredients (or various mixtures thereof) are pumped independently to a mixing head where they are mixed and dispensed onto a conveyor that is lined with paper or plastic. Foaming and curing occurs on the conveyor to form a foam bun. The resulting foams are typically from about from about 10 kg/m³ to 80 kg/m³, especially from about 15 kg/m³ to 60 kg/m³, preferably from about 17 kg/m³ to 50 kg/m³ in density.

A preferred slabstock foam formulation contains from about 3 to about 6 , preferably about 4 to about 5 parts by weight water are used per 100 parts by weight high equivalent weight polyol at atmospheric pressure. At reduced pressure these levels are reduced.

High resilience slabstock (HR slabstock) foam is made in methods similar to those used to make conventional slabstock foam but using higher equivalent weight polyols. HR slabstock foams are characterized in exhibiting a Ball rebound score of 45% or higher, per ASTM 3574.03. Water levels tend to be from about 2 to about 6, especially from about 3 to about 5 parts per 100 parts (high equivalent) by weight of polyols.

Molded foam can be made according to the invention by transferring the reactants (polyol composition including copolyester, polyisocyanate, blowing agent, and surfactant) to a closed mold where the foaming reaction takes place to produce a shaped foam. Either a so-called "cold-molding" process, in which the mold is not preheated significantly above ambient temperatures, or a "hot-molding" process, in which the mold is heated to drive the cure, can be used. Cold-molding processes are preferred to produce high resilience molded foam. Densities for molded foams generally range from 30 to 50 kg/m³.

A description of the raw materials used in the examples is as follows.

DEOA is 99 % pure diethanolamine. Dabco DC 5169 is a silicone-based cell stabilizing surfactant available from Air Products and Chemicals Inc.

Dabco DC 5164 is a silicone-based cell stabilizing surfactant available from Air Products and Chemicals Inc.

TEGOSTAB B-8715 LF is a silicone-based cell regulating surfactant available from Degussa-

Goldschmidt .

TEGOSTAB B-8719 LF is a silicone-based surfactant with both cell stabilizing and cell regulating effect, available from Degussa-

Goldschmidt .

Dabco DC 2525 is silicone-based surfactant with cell regulating effect available from Air

Products & Chemicals Inc.

Span 80 is sorbitan monooleate available from

Aldrich. Dabco 33 LV is a tertiary amine catalyst available from Air Products and Chemicals Inc .

Niax A-I is a tertiary amine catalyst available from GE Specialties . Niax A-300 is a (delayed action) tertiary amine catalyst . available from GE Specialties,

SPECFLEX NC 632 is a 1,700 EW polyoxypropylene polyoxyethylene polyol initiated with a blend of glycerol and sorbitol available from The Dow Chemical Company.

Voranol CP 4702 is a PO/EO triol with an OH number of 35 available from The Dow Chemical Company.

Polyol A is a 1,700 equivalent weight propoxylated tetrol initiated with 3,3'- diamino-N-methyl-dipropylamine and capped with 20 % ethylene oxide.

Polyol B is the reaction product of D. E. R. 732 epoxy resin, available from The Dow Chemical Company, salicylaldehyde, and 3- (N,N-dimethylamino)propylamine, as described in WO 05/063840

SPECFLEX NC-700 is a 40 percent SAN based copolymer pblyol with an average hydroxyl number of 20 available from The Dow Chemical Company.

VORANATE T-80 is TDI 80/20 (2,4-/2,6- isomers) isocyanate available from The Dow Chemical Company.

NOBP A Soybean oil based polyol prepared according to examples 19-22 of WO 2004/096882 having an OH number of 88 and a viscosity at 25 deg C of 1,900 mPa. s

Unless specified, all foams are made in the laboratory by preblending polyols and other additives such as emulsifiers, surfactants, crosslinkers, catalysts and water, conditioned at 25°C. The isocyanate is also conditioned at 25°C. Bench made foam is made by hand-mixing and machine made foam is produced using a high pressure impingement mix-head equipped KM-40 from Krauss- Maffei. At demold, the foam is crushed to avoid shrinkage.

Free rise reactivity and density are recorded by pouring the reactaήts in a bucket and letting the foam rise without any constraint. Molded parts are produced in a 300 x 300 x 100 mm aluminum mold heated at 60⁰C for bench foam and a 400 x 400 x 115 mm mold for machine made foams. All molds are equipped with vent holes. Release agent is Kluber 41-2013, available from Chem-Trend, is used to coat the mold prior to pouring the reactants. Foam properties are measured according to ASTM D 3574-83 test methods, unless otherwise indicated.

Examples 1,2, 3 and 1C

Production of molded flexible HR foam having high airflow and low compression sets values are produced using the formulations in Table 1. The foams are produced by hand-mixing. For Examples 1-3, a cell regulating surfactant is combined with NOBP, while comparative Example 1C uses a cell stabilizing surfactant. The properties of the produced foams are also given in Table 1.

Table 1

4C is a comparative example, not part of th s nvent on.

HACS means Humid Aged Compression Set. Wet compression set (with skin) is measured according to Renault RP 1637 test method. These data show foam produced with NOBP A and a cell regulating surfactant have compression sets (dry, wet and after humid aging) comparable to a conventional HR molded system currently used by the industry. Comparative Example 2C and Example 4

Molded foams are produced by hand-mixing, using the formulations given in Table 2 where the NOBP is fifty percent of the polyol component. Comparative Example 2C contains a Dabco DC 5169, a cell-stabilizing silicones-based surfactant and Example 4 contains Tegostab B8715 LF, a cell regulating additive.

Table 2

5C is a comparative example, not part of this invention

The foam of Example 2C produces a sponge foam with large cells across the entire pad. Such a foam is generally unsuitable for automotive seating. Utilizing a cell regulating additive as per Example 4, gives a good foam with small, irregular cells typical of HR foam, and the foam has no visible surface defects.

Comparative Example 3C

For a comparative, when 0.4 PPHP (part per hundred part of polyol) of Dabco DC 5164, a strong cell stabilizing surfactant, is added to formulation 2C, a foam with fine cells is obtained. However this foam pad is very tight and cannot be demolded without being deformed. Furthermore 75 % compression set is 21 %, hence is outside of the Opel 60283-4-96 specification. Hence this combination of surfactants commonly recommended for the production of molded foams, is not suitable when NOBPs are used as a substantial portion of the polyol formulation. While adjusting the ratios between these surfactants may be possible to produce an acceptable foam, it is believed the processing widow in such a case would be narrow.

Examples 5 and 6

Production of low density, flexible polyurethane foam are made with a high pressure KM-40 machine, using NOBP A as intrinsic bulk stabilizing surfactant and a cell regulating surfactant. The formulations and foam properties are given in Table 3. These foams exhibit high air-flows and superior dynamic fatigue characteristics according to Peugeot PSA D42 1047 test method: 200,000 cycles between 25 and 75 % compression at 3 Hz, measurement of foam thickness loss (specification < 5 %) and hardness loss (specification < 15 %) after 30 minutes recovery time.

Table 3

These foam properties confirm that NOBP based foams are performing as well as current systems used by the industry for automotive seating, and that increasing the NOBP level from 20 up to 40 PPHP does not harm compression sets. There is no foam collapse under vent-holes indicating the foams are stable during foaming although they are very open. Example 7 and Comparative Example 4C

Molded foams are made with a formulation containing 40 PPHP of NOBP as given in Table 5. The properties of the foams are also given in Table 5. The results show when a cell regulating surfactant is used in the formulation (Example 7) , foams with proper physical characteristics, especially compression sets, are obtained. Without the addition of a cell regulating surfactant (4C) foam is overstabilized by the high level of NOBP (40 PHP) and compression sets suffer. In addition, the bottom surface of the part is improved by the addition of the cell regulating additive.

Table 5

Example 4C is a comparat ve example, not part of th s nvent on Examples 8 and 9

Foams made with the formulations of Table 6, containing Dabco DC 2525, a cell regulating silicone based surfactant, show good cell structure. Table 6

While the cells show good structure, the bottom surface shows a layer of 1 mm sized, large cells. Addition of Span 80, an organic emulsifier, reduces substantially the number and the size of these large cells.

Examples 10 and 11

Two molded foams are produced using 40 PPHP of NOBP A and two different catalyst compositions. The formulations are given in Table 2. Use of autocatalytic polyols A and B, as in example 10, shows such polyols may be used to replace conventional amine catalysts when NOBP comprise a substantial portion of the polyol composition.

Table 7

EXAMPLE 12

A molded foam with acceptable properties is produced when using as the polyisocyanate component, a blend of 80 % TDI 80/20 and 20 % Voranate M-229, a polymeric MDI, with the following polyol composition given in Table 8. The demold time is 6 minutes and the foam has a density of 37.4 kg/m³ and an airflow of 4.5 cfm.

Table 8

Other embodiments of the invention will be apparent to those skilled in the art from a consideration of this specification or practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.

Claims

WHAT IS CLAIMEDIS:

1 A process for the production of a polyurethane foam by reaction of a mixture of

(a) an isocyanate component containing at least 60 weight percent toluene diisocyanate;

(b) a polyol composition comprising

(bl) up to 80 percent by weight of at least one polyol compound having a nominal starter functionality of 2 to 8 and a hydroxy1 number from 15 to 200, and

(d) in the presence of 0.5 to 10 parts of polyol of water as blowing agent ; and

(e) optionally additives or auxiliary agents known per se for the production of polyurethane foams,- wherein the total mixture contains substantially no silicone based cell stabilizing surfactant .

2. The process of claim 1 wherein (b2) is from 30 to 85 percent by weight of the total polyol.

3. The process of claim 1 wherein the polyisocyanate component comprises 80 weight percent or greater of the total polyisocyanate .

4. The process of claim wherein the polyisocyanate component comprises a mixture of toluene diisocyanate and methylene diisocyanate .

5. The process of any of the preceding claims wherein the amount of the cell regulator is less than 1.0 parts by weight of the total polyol .

6. The process of any one of the preceding claims wherein the cell regulator is an organopolysiloxane .

7. The process of claim 6 wherein the cell regulator is a methyl polysiloxane.

8. The process of any of the preceding claims wherein (bl) contains at least one polyol containing a tertiary amine group in the polyol chain, a polyol initiated with an initiator containing a tertiary amine or a polyol partially capped with a tertiary amine group.

9. The process of claim 8 wherein the polyol containing a tertiary amine comprises from 1 to 50 weight percent of the total polyol .

10. The process of claim 9 wherein the polyol containing a tertiary amine comprises from 5 to 40 weight percent of the total polyol .

11. The process of claim 8 wherein the initiator containing a tertiary amine is at least one initiator of Formula I

H_1nA- (CH₂)_n-N (R) - (CH₂)p-AH_m Formula (I) wherein n and p are independently integers from 2 to 6,

R is a C₁ to C₃ alkyl group, m is equal to 0 when A is hydrogen, is 1 when A is oxygen and is 2 when A is nitrogen, or Formula II

H₂N- (CH₂) _m-N- (R) -H Formula (II) where m is an integer from 2 to 12 and R is a C₁ to C₃ alkyl group .

12. The process of claim 11 wherein the initiator is at least one of 3, 3' -diamino-N-methyldipropylamine, 2 , 2 ' -diamino-N- methyldiethylamine, 2 , 3-diamino-N-methyl-ethyl-propylamine N- methyl-1 , 2 -ethanediamine and N-methyl-1, 3-propanediamine.

13. The process of claim 1 wherein (bl) contains at least one polyol containing at least one imine linkage and one tertiary amine.

14. The process of claim 13 wherein the polyol of claim 13 comprises from 0.5 to 2 weight percent of the total polyol .

15. The process of claim 1, wherein the natural oil based polyol is derived from natural oils of castor, soybean, olive, peanut, rapeseed, corn, sesame, cotton, canola, safflower, linseed, palm, sunflower seed oils, or a combination thereof.

16. The process of claim 15 wherein in the natural oil based polyol is derived from a castor oil, soybean oil or a combination thereof.

17. The process of claim 15 or wherein the natural oil based polyol contains from 10 to 50 weight percent of ethylene oxide .

18. The process of claim 17 wherein the polyol is derived from a natural oil which is treated by epoxidation, hydroxylation, esterification, hydrofroymlation, or a combination thereof, followed by reaction with an ethylene oxide or a mixture of ethylene oxide and at least one other alkylene oxide.

19. The process of 15 wherein the natural base polyol is derived from a natural oil based polyol produced by the steps of transesterification of the natural oil, recovery of the constituent fatty acids, hydroformylation of the fatty acids to form hydroxymethyl group, and then formation of a polyol by reaction of the hydroxymethylated fatty acid with an initiator compound having 2 to 8 active hydrogen atoms.

20. The process of claim 19 wherein the initiator is glycerol; ethylene glycol; 1 , 2-propylene glycol; trimethylolpropane; ethylene diamine; pentaerythritol,- diethylene triamine; sorbitol; sucrose; or any of the aforementioned where at least one of the alcohol or amine groups present therein has been reacted with ethylene oxide, propylene oxide or mixture thereof; or combination thereof .

21. The process of any of the preceding claims wherein the polyol contains from 0.2 to 3 parts by weight of the total polyol of a polyol with a nominal functionality of 4 to 12, a molecular weight from 5,000 to 100,000 wherein such polyol contains at least 50 weight percent oxyethylene units.

22. The process of any of the preceding claims wherein the reaction mixture contains from 0.1 to 10 weight percent of an emulsifier .

23. A polyurethane foam produced by the process of any one of the preceding claims .

24. A flexible polyurethane foam, having a density below 50 kg/m³, which is the reaction product of an isocyanate component containing at least 60 percent by weight of TDI and a polyol component comprising

(i) up to 80 percent by weight of the total polyol of at least one polyol compound other than (ii) having a nominal starter functionality of 2 to 8 and a hydroxyl number from 15 to 200;

(ii) from 20 to 100 percent by weight of the total polyol of at least one natural oil based polyol with a OH number below 300 and a viscosity below 6,000 mPa.s;

(iii) from 0.01 to 1.5 parts by weight of polyol of a cell regulating agent;

(iv) from 0.5 to 10 parts water as blowing agent; and

(v) optionally additives or auxiliary agents known per se for the production of polyurethane foams,- wherein the total mixture contains substantially no silicone based cell stabilizing surfactant.

25. The foam of claim 24 wherein the polyol of <i) contains at least one polyol having a functionality of 2 to 6 and an equivalent weight per hydroxyl group of from 1,000 to 3,000.

26. The foam of claim 24 wherein the polyol (i) , (ii) or both contain at least 30 percent primary hydroxyl groups.

27. A polyol formulation comprising (i) up to 80 percent by weight of the total polyol of at least one polyol compound having a nominal starter functionality of 2 to 8 and a hydroxyl number from 15 to 200; (ii) from 20 to 100 percent by weight of the total polyol of at least one natural oil based polyol with a OH number below 300 and a viscosity below 6,000 mPa.s;

(iii) from 0.01 to 1.5 parts by weight of polyol of a cell regulating agent;

(iv) from 0.5 to 10 parts water as blowing agent; and