MXPA00010911A - Tertiary amine-containing active methylene compounds for improving the dimensional stability of polyurethane foam - Google Patents

Abstract

A method for making flexible polyurethane foam in which a polyisocyanate is reacted with a polyol in the presence of a urethane catalyst, a blowing agent, optionally a silicone surfactant cell stabilizer, and a cell opening additive. The cell opening additive comprises an active methylene or methine compound which also contains a tertiary amine. Preferred cell opening additives are 2-cyano-N-Ä3-(dimethylamino)-propylÜacetamide and (NC)CH2C(O)OCH2CH2N(CH3)CH2CH2OCH2CH2N(CH3)2.

Description

ACTIVE METHYLENE COMPOUNDS CONTAINING TERTIARY AMINE TO IMPROVE DIMENSIONAL FOAM STABILITY POLYURETHANE DESCRIPTION OF THE INVENTION Flexible molded polyurethane foam requires mechanical compression to open the foam cells and prevent shrinkage. The prevention of shrinkage results in improved dimensional stability. The current mechanical methods for opening cells consist mainly of compression, vacuum rupture or the release of time pressure. However, these methods usually result in incomplete or inconsistent cell opening and require the foam producer to investigate additional work and machines. A chemical method for opening cells that can be incorporated into the foam production process is therefore preferred. Current chemical methods for opening cells have disadvantages such as requiring large amounts of additive (often as high as 1-5 parts per hundred parts of polyol) or adversely affecting the physical properties of the cell. Some examples of current chemical methods for opening polyurethane foam cells are described below: U.S. Patent 4,211,849 (Kollmeier et al., 1980) describes a process for producing an open cell polyurethane foam by mixing a polyol with a polyisocyanate, a catalyst, a blowing agent, and a crystalline polyhydroxy crosslinker, such as sorbitol, mannitol, trimethylolmelamine, and glucose, having at least 3 hydroxy groups. U.S. Patent 4,751,253 (Tylenda, 1988) describes the use of an additive comprising an ester reaction product of a large chain acid with polyethylene or polypropylene glycols and / or containing free acid to produce a urethane foam product flexible, dimensionally stable open cell. United States Patent 4,929,646 (Nichols et al., 1990) discloses high functionality, high molecular weight poly (oxyethylene) compounds as openers and cell softeners. The compounds sor. reported to be highly effective in opening foam cells based on PIPA polyols and in softening foams made of MDI-based polyisocyanates. U.S. Patent 5,039,713 (Petrella, 1991) and U.S. Patent 5,057,480 (Petrella, 1991) describes the blowing reaction catalysts for the production of polyurethane foams. Tertiary amine catalysts consisting essentially of 25 to 80% by weight of pentamethyldietiler.-riamine and 20 to 75% of bis (dimethylaminopropyl) methylamine are reported to provide foam cell opening resulting in improved breathability. U.S. Patent 471,260 (1992) describes a process for the production of open cell, flexible polyurethane foam in which organic acids, such as benzoic, salicylic or adipic acid or an alkali metal salt of the acid is used as an additive. U.S. Patent 5,192,812 (Farris et al., 1993) discloses the use of siloxane-oxyalkylene copolymers as cell openers in the production of urethane foams, when used in combination with silicone surfactants. U.S. Patent 5,489,618 (Gerkin, 1996) discloses the use of an amine salt, formed by the reaction between a tertiary amine and a carboxylic acid having hydroxyl functional groups, to produce polyurethane foams. It is reported that the amine sai produces foams that are either more open or more easily opened, or both, and have a reduced tendency to shrink. U.S. Patent 5,807,958 (Diblitz et al., 1998) discloses salts of alkaline metal and alkaline ferrous metals of alkyl and succinic alkenyl acids as catalysts for making polyurethane foam. The catalysts are reported to have a favorable influence on the cell structure of the foam.

This invention is directed to a method for foaming polyurethane in which an active methine or methylene compound containing a tertiary amine is used as a cell opening additive. The following advantages are achieved using the cell opening additives of this invention: The additive is highly effective for polyurethane foam systems based on toluene diisocyanate; The force values to compress the foams are dramatically reduced; The dimensional stability of the foam is improved, thus reducing shrinkage; The physical properties of the foam are not adversely affected by the additive; Relatively low levels of the additive (0.001 a 2. 5 pphp) are necessary to create cell aperture; and The additive can also act as a catalyst, due to the presence of a tertiary amine moiety. For purposes of this invention and as understood by many in the art, flexible molded foams may include microcellular foams such as those used in shoe soles and steering wheels, as well as flexible molded foams used in a variety of applications such as furniture, beds and car seats. The cell opening additive contains both the active methylene or methine group and a tertiary amine group. The active methylene and methine compounds are carbon acids that contain electron attraction groups. The electron attraction groups act to increase the acidity of neighboring carbon hydrogen bonds by stabilizing the conjugate base that is formed after deprotonation (TH Lowry and KS Richardson, Mechanism and Theory in Organic Chemistry, 2nd Ed., 1981, p. 262-281). Typical electron attraction groups are -CN, RC (O) -, RS02-, ROC (O) -, where R is any alkyl or aryl group. Conversely, the presence of an electron donation group, such as an alkyl group, can decrease the acidity of neighboring hydrogen carbon bonds. The relative acidity of these types of compounds can be determined by a number of methods. A common method is to measure the equilibrium constant for dissociation, Ka, of the 'compounds. Tables of pKa values for a variety of Bronsted acids are readily available (for example in J.A. Dean, Lange's Handbook of Chemistry, 14th Ed., 1992, pp. 8.19-8.71). However, the solvent plays a large part in determining the acidity in solution; therefore, one must be careful to compare the pKa values that have been obtained using diluted solutions of the compounds in the same solvent at the same temperature. Alternatively, the gas phase acidity (? Hi) of the compounds can be measured or calculated in order to obtain relative acidity of these types of compounds. Due to the strong role that the solvent plays in determining the acidity of the compounds in solution, certain active methylene and methine compounds will work better as cell openers if they dissolve in water than if they were supplied as a pure liquid or as solutions in solvents less polar. Many of the compounds that are effective in improving dimensional stability (reducing shrinkage) of polyurethane foam have pKa values that are less than about 10.8 (measured in water at 25 ° C). However, the pKa values of active methylene and methine compounds that are less soluble in water may be erroneous. Because of this, the compounds of this invention are not limited to having a pKa value within the specified range. Examples of cell opener additives of this invention are esters containing tertiary amine, amides, and thioesters of cyanoacetic acid, 1,3-acetone dicarboxylic acid, and substituted acetic acids in which the substituents are electron-attracting groups. The following are various classes of compounds of this invention.

A class of compounds is esters of cyanoacetic acid having the general formula wherein Y is a substituted C6-C10 aryl or CXX'X "wherein X, X ', and X" are, independently hydrogen, halogen, substituted or unsubstituted C1-C20 alkyl, C1-C20 alkyl ether, C1-C20 alkylamino, substituted or unsubstituted C6-C10 aryl, and at least one of the Y substituents contains a tertiary amine group. Examples of specific compounds within this group are shown below: in which n is 1 or 2. Another class of compounds is. amides of cyanoacetic acid having the general formula: wherein Y and Y 'are, independently, a substituted C6-C10 aryl or CXX'X "wherein X, X', and X", are, independently, hydrogen, halogen, substituted C1-C20 alkyl or not substituted, C1-C20 alkyl ether, C1-C20 alkylamino, substituted or unsubstituted C6-C10 aryl, and at least one of the Y or Y 'substituents contains a tertiary amine group. Examples of specific compounds within this group are shown below: in which n = 1 or 2. Another class of compounds is thioesters of cyanoacetic acid having the general formula: wherein Y is a substituted C6-C10 aryl or CXX'X "wherein X, X ', and X" are, independently, hydrogen, halogen, substituted or unsubstituted C1-C20 alkyl, C1-C20 alkyl ether, C1-C20 alkylamino, substituted C6-C10 aryl or unsubstituted, and at least one of the substituents in Y contains a tertiary amine group. Examples of specific compounds within this group are: in which n = integers of 1 a. Another group of compounds is esters of ketocarboxylic acids having the general formula: wherein R is a substituted or unsubstituted C1-C20 alkyl or a substituted or unsubstituted C6-C10 aryl, and Y is a substituted or unsubstituted C6-C10 aryl or CXX'X "wherein X, X ', and X' are, independently, hydrogen, halogen, substituted or unsubstituted C1-C20 alkyl, C1-C20 alkyl ether, C1-C20 alkylamino, substituted or unsubstituted C6-C10 aryl and at least one of the Y substituents contain a tertiary amine group. Examples of specific compounds within this group are: in which n is 1 or 2. Another group of compounds is ketocarboxylic acid amides having the general formula: wherein R is a substituted or unsubstituted C1-C20 alkyl or a substituted or unsubstituted C6-C10 aryl, and Y and Y 'are, independently, a substituted C6-C10 aryl or CXX'X "er Wherein X, X ', and X "are independently, hydrogen, halogen, substituted or unsubstituted C1-C20 alkyl, C1-C20 alkyl ether, C1-C20 alkylamino, substituted or unsubstituted C6-C10 aryl, and at least one of the substituents on Y or Y 'contains a tertiary amine group. Examples of specific compounds within this group are shown below: wherein n is 1 or 2. Another group of compounds is thioesters of ketocarboxylic acids having the general formula. wherein R is a substituted or unsubstituted C1-C20 alkyl or a substituted or unsubstituted C6-C10 aryl, and Y is a substituted C6-C10 aryl or CXX'X "wherein X, X ', and X "are, independently, hydrogen, halogen, substituted or unsubstituted C1-C20 alkyl, C1-C20 alkyl ether, C1-C20 alkylamino, substituted or unsubstituted C6-C10 aryl, and at least one of the substituents in Y contains a tertiary amine group. Examples of specific compounds within this group are shown below: wherein n = integers from 1 to 4. Another group of compounds is esters of 1,3-acetone dicarboxylic acids having the general formula wherein Y and Y 'are independently, a substituted C6-C10 aryl or CXX'X "wherein X, X', and X" are, independently, hydrogen, halogen, substituted or unsubstituted C1-C20 alkyl, alkyl ether, alkylamino, substituted or unsubstituted C6-C10 aryl, and at least one of the substituents on Y or Y 'contains a tertiary amine group. Examples of specific compounds within this group are shown below: in which n = 1 or 2. Another group of compounds is 1,3-acetone dicarboxylic acid amides having the general formula: wherein Y, Y ', Y "and Y' '', are independently, a substituted C6-C10 aryl or CXX'X" wherein X, X ', and X "are independently, hydrogen, halogen, C1-C20 substituted or unsubstituted, C1-C20 alkyl ether, C1-C20 alkylamino, substituted or unsubstituted C6-C10 aryl, and at least one of the substituents on Y, Y, Y "or Y '' ' , contains a tertiary amine group. Examples of specific compounds within this group are shown below: in which n is 1 or 2. Another group of compounds is thioesters of acid 1,3-acetone dicarboxylic having the following formula: wherein Y and Y 'are, independently, a substituted C6-C10 aryl or CXX'X "wherein X, X', and X" are independently, hydrogen, halogen, substituted or unsubstituted C1-C20 alkyl , C1-C20 alkyl ether, C1-C20 alkylamino, substituted or unsubstituted C6-C10 aryl, and at least one of the substituents on Y or Y 'contains a tertiary amine group. Examples of specific compounds within this group are where n is an integer of 1 a.

Compounds derived from 1,3-acetone dicarboxylic acid containing an amide group and an ester group, an amide group and a thioester group, or an ester group and a thioester group as described above are also met within this invention. Another group of compounds is esters of substituted acetic acids in which the substituents are electron-attracting groups. The compounds have the general formula. in which Y is a substituted C6-C10 aryl or CXX'X "wherein X, X ', and X" are, independently, hydrogen, halogen, substituted or unsubstituted C1-C20 alkyl, C1-C20 alkyl ether, C1-C20 alkylamino, substituted C6-C10 aryl or unsubstituted, and at least one of the substituents on Y contains a tertiary amine group and D and D 'are, independently, electron attraction substituents such as N02, CN, F, Cl, Br, CF3, I, C (0) OR, C (0) R, CHO and C (0) NH2. Examples of specific compounds within this group are shown below: wherein R is N02, CF3, or Ci and n is 1 or 2. Another group of compounds is substituted acetic acid amides, in which the substituents are electron-attracting groups, having the general formula: wherein Y and Y 'are independently, substituted or unsubstituted C1-C20 alkyl, C1-C20 alkyl ether, C1-C20 alkylamino, substituted or unsubstituted C6-C10 aryl, and at least one of the substituents in Y or Y 'contains a tertiary amine group, and D and D' are, independently, electron attraction substituents such as N02, CN, F, Cl, Br, CF3, I, c, 0) 0R, C (0) R, CHO and C (0) NH2, preferably CN.

In the above formulas, the alkyl of Cl to C20 may be linear or branched; for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl, 2-ethylhexyl, n-decyl, cetyl, stearyl, and the like, especially alkyl groups from Cl to CIO. These can be substituted with aryl, heterocyclic, halide, hydroxy, amino, alkoxy, phenoxy, nitro, keto, cyano alkylamino, thio, carboxylate and the like. In the above formulas, C6 to CIO aryl can be phenyl or naphthyl, optionally substituted with alkyl, aryl, halide, hydroxy, amino, alkoxy, phenoxy, nitro, keto, cyano, alkylamino, thio, carboxylate, and the like. Preferred groups Y for the above formulas are those derived from aminoalkylamines, alcoholamines, and thiolamines, such as those having the following formulas: H2 nSH , and in which R and R 'are, independently, C1-C4 alkyl, n, n', n "and n '' 'are integers from 1 to 20, and R "and R '' 'are, independently, hydrogen, an alkyl, an alkyl ether, an alkylamine, or an alkylthioether, in which alkyl is C1-C20. Examples of preferred groups Y are those derived from 3- (dimethylamino) -propylamine, 3-dimethylamino-1-propanol, dimethylaminoethanol, trialkanolamines such as triethanolamine and tris (2-hydroxypropyl) amine, triaminoalkylamines, 1-hydroxyalkylpyrrolidines, 1-aminoalkylpyrrolidines, 1-hydroxyalkylimidazole, 1-aminoalkylimidazole, bis (aminoethyl) ether derivatives such as 2- [N- (dimethylaminoethoxyethyl) -N-methyl-amino] ethanol and 2- [N-dimethylaminoethoxyethyl] -N-methylamino] -1-methylethanol , tetramethyldiethylenetriamine, (CH3) 2NCH2CH2N (CH3) CH2CH2OH, [(CH3) 2NCH2CH2CH2] 2N (CH2CH2OH), [(CH3) 2NCH2CH2CH2] 2N (CH2CH (CH30H), an N-hydroxyalkylmorpholine, an N-aminoalkylmorpholine, a hydroxyalkylpyrrolizidine, an aminoalkylpyrrolizidine, a hydroxyalkylnuclidine, an aminoalkylnuclidine, a hydroxyalkyltriethylenediamine, a aminoalkyltrietylenediamine, 3-quinuclidinol, and urea and amide derivatives of the tertiary amines described above The preferable cell additives are 2-cyano-N- [3- (dimethylamino) propyl] acetamide and (NC) CH2C (O) OCH2CH2N (CH3) CH2CH2OCH2CH2N (CH3) 2. The cell opener is preferably used at levels of 0.001 to 2.5 parts per hundred parts of polyol (ppcp), more preferably 0.005 to 1.5 ppc, and more preferably 0.01 to 0.5 ppcp. The cell opener can be supplied as a pure liquid or dissolved in one of the compounds of the formulation such as the surfactant, water, crosslinker, polyol, amine catalyst, or catalyst. The cell-opening additives according to the invention are used in the manufacture of polyurethane and polyester flexible polyurethane foams in the manner known in the art. In producing the polyurethane foams using these cell openers, one or more polyether or polyester polyols are employed for reaction with a polyisocyanate, especially a diisocyanate, to provide the urethane linkage. Such polyols have an average of typically 2.0 to 3.5 hydroxyl groups per molecule, hydroxyl numbers of 20 to 60, and weight average molecular weights of 2000 to 7000 daltons (units of atomic mass). The density of a flexible polyurethane foam can be 0.6-25 lb / ft3 (10-400 kg / m3). Illustrative of suitable polyols are polyalkylene ether and polyester polyols as a component of the polyurethane composition. Polyalkylene ether polyols include poly (alkylene oxide) polymers such as poly (ethylene oxide) and poly (propylene oxide) polymers and copolymers with terminal hydroxyl groups derived from polyhydric compounds, including diols and triols; for example, among others, ethylene glycol, propylene glycol, 1,3-butane diol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, pentaerythritol, glycero, diglycer, trimethylol propane and the like low molecular weight polyols . In the practice of this invention, a high molecular weight polyether polyol can be used. Also, mixtures of high molecular weight polyether polyols such as mixtures of di and trifunctional materials and / or different materials of different chemical composition or of different molecular weight can be used. Polyester useful polyols include those produced by reacting a dicarboxylic acid with an excess of a diol, for example, adipic acid with ethylene glycol or butanediol, or reacting a lactone with an excess of a diol such as caprolactone with propylene glycol. In addition to polyether and polyester polyols, master batches, or premix compositions, frequently contain a polyol polymer. The polyols polyols are used in flexible polyurethane foam to increase the foam resistance to deformation, ie to increase the load carrying properties of the foam. Currently, two different types of polyol polymers are used to achieve load carrying improvement. The first type, described as a graft polyol, consists of a triol in which the vinyl monomers are copolymerized by grafting. Styrene and acrylonitrile are the usual monomers of choice. The second type, a polyurea modified with polyurea, is a polyol containing a polyurea dispersion formed by the reaction of a diamine and a toluene diisocyanate (DIT). Since the DIT is used in excess, some of the DIT can react with both the polyol and the polyurea. This second type of polyol polymer has a variant called PIPA polyol which is formed by the in situ polymerization of DIT and alkanolamine in the polyol. Depending on the load carrying requirements, the polyol polymers can comprise 20-80% of the polyol portion of the masterbatch. The polyurethane products are prepared using any suitable organic polyisocyanate well known in the art including, for example, hexamethylene diisocyanate, phenylene diisocyanate, toluene diisocyanate (DIT), and 4,4'-diphenyl methane diisocyanate (DIM) . 2,4-DIT and 2,6-DIT are particularly suitable, individually, or together as their commercially available mixtures. Other suitable isocyanates are mixtures of diisocyanates known commercially as "unpurified" "MID" also known as PAPI, which contain about 60% DIM together with other isomeric and analogous higher polyisocyanates. "Prepolymers" of these polyisocyanates comprising a polyisocyanate are also suitable. prereacted mixture of a polyisocyanate and a polyether or polyester polyol The suitable urethane catalysts useful for making flexible polyurethane foams are all those well known to those skilled in the art and include tertiary amines such as those used to catalyze the acid anhydride reaction. alcohol, such as triethylendia ina, N-methylimidazole, 1,2-dimethylimidazole, N-methylmorpholine, N-ethyl morpholine, triethylamine, tributylamine, triethanolamine, dimethylethanolamine and bis (dimethylaminoethyl) ether, and organotins such as stannous octoate, acetate stannous, tin oleate, stannous laurate, dilaurate of dibutyltin and other tin salts. Other typical agents found in flexible polyurethane foam formulations include chain extenders such as ethylene glycol and butanediol; crosslinkers such as diethanolamine, diisopropanolamine, triethanolamine and tripropanolamine; blowing agents such as water, liquid carbon dioxide, CFC, HCFC, HFC, pentane, and the like, especially water or water and HCFC; and cell stabilizers such as silicones. Flexible polyurethane foams that can be prepared using the present invention include slab supply foams having a density of 12-100 kg / m 3, such as based on polyether: conventional (12-60 kg / m 3), high elasticity (18-80 kg / m3), filled (40-100 kg / m3), semi-rigid (22-35 kg / m3); and based on polyester: technical grades (20-50 kg / m3), lamination grades (20-35 kg / m3) and semi-rigid (22-35 kg / m3) as well as molded foams that have a density of 22-300 kg / m3, such as based on polyether: conventional hot cure (22-50 kg / m3), high elasticity and cold cure (28-55 kg / m3), semi-rigid (40-150 kg / m3), polyester base (50-150 kg / m3), "repol" or reinserted (60-300 kg / m3). Microcellular molded foams having a core density of 400-600 kg / m 3, a skin density of 600-800 kg / m 3 and a total density of 500-700 kg / m 3 are also possible. A general polyurethane flexible molded foam formulation having a density of 0.6-25 lb / ft3 (10-400 kg / m3), eg, 1-3 lb / ft3 (16-48 kg / m3) automotive seats, which contains a cell / stabilizer opener according to the invention may comprise the following components in parts by weight (ppp): Formulation of flexible foam PPP Polyol 20-100 Polymer polymer 0-80 Silicone surfactant 0.5-2.5 Cell opener 0.05-3 Blowing agent (for example water) 1-8 Auxiliary blowing agent 0-4.5 Reticulator 0.5-2 Composition of catalyst 0.1-5 isocyanate index * = 70-115 * Isocyanate index = (isocyanate-moles / active hydrogen moles) x 100 In the present invention, the preferred blowing agent for making flexible molded foams is water. Water is used in 1 to 8 parts per hundred polyol (ppcp), especially 3 to 6 ppcp, and may optionally be used with other blowing agents. Other additives can of course be employed to impart specific properties to flexible foams. Examples of flame retardants, colorants, fillers and hardness modifiers. The polyurethane foams of this invention can be formed in accordance with any of the processing techniques known in the art, in particular, the "one shot" technique. In accordance with this method, foamed products are provided by reacting the polyisocyanate and polyol simultaneously with the foaming operation. It is sometimes convenient to add the cell stabilizer / opener to the reaction mixture as a premix with one or more of the blowing agents, polyol, water and catalyst components. The invention is further clarified by a consideration of the following examples, which are proposed to be purely exemplary of the invention. EXAMPLE 1 PREPARATION OF 2-CYANO-N- [3- (DIMETHYLAMINO) PROPYL] ACETAMIDE Ethyl cyanoacetate (51.106 g, 0.4518 mol) is added to 3- (dimethylamino) propylamine (46.162 g, 0.4518 mol) in a bottom flask round 250 ml equipped with a magnetic stirring bar. After stirring for approximately 0.5 hr, 50 ml of toluene is added. The light orange liquid is stirred at room temperature for approximately 15 hours, after which the ethanol and toluene are removed via a vacuum distillation. 2-Cyano-N- [3- (dimethylamino) propyl] acetamide is obtained in 96% yield. EXAMPLE 2 PREPARATION OF DIT FLEXIBLE MOLDED POLYURETHANE FOAM USING A CHEMICAL CELL OPENER OF THIS INVENTION The formulation for preparing a flexible molded foam of DIT (Table I) is shown below: Table I Component Parts by weight Arcol E-648 Polyether polyol 1 60.0 Arcol E-519 Styrene-Acrylonitrile 40.0 Polyol DABCO® DEOA-LF (75% diethanolamine 1.75 in water) 2 Silicone surfactant2 DABCO® DC- 0.60 5169 Silicone surfactant2 DABCO® DC-0.20 5164 Water (total) 3.50 Amine catalyst2 DABCO® 33 LV 0.21 Amine catalyst2 DABCO® BL-11 0.10 2-cyano-N- [3- (dimethylamino) propyl] acetamide 0.07 Mondur TD-803, DIT index = 105 1 of Arco Chemical from Air Products and Chemicals, Inc. 3 of Bayer Corp. (80:20, 2, 4-: 2,6-toluene diisocyanate) A resin premix is prepared by combining the polyols, DEOA-LF, surfactants, water, catalysts, and (in Example 2) a cell opening catalyst of this invention. This liquid is then mixed for 3-5 minutes using a fixed Premier Mili mixer between 2000-6000 rpm. The resin premix is stored in an incubator at 20 ° C until needed. The desired amount of the premix is weighed in a 32-ounce cup tared. The corresponding amount of DIT is then added to this "B side" mixture and the resulting liquid is mixed for 5 seconds at 5000 rpm using a Servodyne® lab mixer. The mixture is emptied into a 12 in. X 12 in. X 3 in. (30.48 x 30.48 x 7.62 cm) mold which has been preheated to 155-165 ° F (68.3-73.8 ° C) and sprayed with a release agent solvent-based (PRC-798); the cup is held in an inverted position for 5 seconds, and the mold is immediately closed. The formulation is allowed to react in the mold for 5 minutes, after which it is immediately demoulded and weighed. COMPARATIVE EXAMPLE 3 PREPARATION OF DIT FLEXIBLE MOLDED POLYURETHANE FOAM NO USING CHEMICAL CELL OPENER The flexible molded polyurethane foams of DIT are prepared in this example using the formulation in Table II. The level of use of the amine catalyst DABCO® 33 LV has to be increased to 0.25 ppcp of polyol (more than 0.21 ppcp) in order to meet the elastic gel time in example 2. Table II Component Parts by weight Arcol E-648 Polyether polyol 1 60.0 Arcol E-519 Styrene-Acrylonitrile 40.0 Polyol DABCO® DEOA-LF (75% diethanolamine 1.75 in water) 2 Silicone surfactant2 DABCO® DC- 0.60 5169 Silicone surfactant2 DABCO® DC-0.20 5164 Water (total) 3.50 Amine catalyst2 DABCO® 33 LV 0.25 Amine catalyst2 DABCO® BL-11 0.10 Mondur TD-803, DIT index = 105 1 from Arco Chemical 2 of Air Products and Chemicals, Inc. 3 of Bayer Corp. EXAMPLE 4 COMPRESSION VALUES The foams of Example 2 and Comparative Example 3 are placed in a compression force apparatus immediately after demolding; The first compression cycle is 60 seconds after demolding. The force sensing device is equipped with a 1000-pound pressure transducer mounted between the 50-square-inch circular plate and the drive shaft. The current pressure appears on a digital screen. The pad is compressed to 50 percent of its original thickness and the force required to achieve the highest compression / cycle is recorded in total pounds. The various compression cycles are completed. A cycle takes approximately 30 seconds to complete. This device mimics the indentation force deflection test, ASTM D-3574, and provides a numerical value of initial hardness or softness of the newly demoulded foams. The values are reported as the FTC value for the foam, based on the presumption that the FTC values are lower the more open the foam is. This test requires that the foam be cured to an acceptable demoulding. The average values for three foams are reported in Table III. Table III The data in Table III show that extremely good dimensional stability of the polyurethane foam is achieved using a chemical cell opener of this invention, compared to foams prepared without chemical release opener. Note that the foam of example 2, in which a cell opener of this invention is used, has a considerably better compressive force value than the comparative example 3. The foam of example 2 can therefore have much better dimensional stability compared to the foam of comparative example 3.

Claims (2)

CLAIMS 1. A method for preparing a flexible polyurethane foam which is characterized in that it comprises reacting a polyisocyanate with a polyol in the presence of a urethane catalyst, a blowing agent, optionally a silicone surfactant cell stabilizer and an amount effective of a cell opener additive, wherein the cell opener additive comprises an active methylene or methine compound containing at least one tertiary amine. The method according to claim 1, characterized in that the cell-opening additive comprises a compound represented by one of the formulas: wherein Y and Y 'are, independently, substituted C6-C10 aryl or CXX'X "wherein X, X', and X" are, independently, C1-C20 alkyl, C1-C20 alkyl ether, C1 alkylamino -C20, C6-C10 aryl, substituted C1-C20 alkyl, or substituted C6-C10 aryl, and at least one of the substituents on Y or Y 'contains a tertiary amine group. 3. The method according to claim 1, characterized in that the cell opening additive comprises a compound represented by one of the formulas: where Y and Y 'are, independently, aryl of Substituted C6-C10 or CXX'X "wherein X, X ', and X" are, independently, C1-C20 alkyl, C1-C20 alkyl ether, C1-C20 alkylamino, C6-C10 aryl, substituted alkyl C1-C20, or substituted C6-C10 aryl, and at least one of the substituents on Y or Y 'contains a tertiary amine group and D is an electron-withdrawing substituent selected from the group consisting of N02, Cl, Br, CF3, I, C (0) OR, C (0) R, CHO and C (0) NH2. 4. The method according to the separation 1, characterized in that the cell opening additive comprises a compound represented by one of the formula A, B, C or D: or A B wherein R is a C1-C20 alkyl, substituted C1-C20 alkyl, a C6-C10 aryl or a substituted C6-C10 aryl; and Y and Y 'are, independently, a substituted C6-C10 aryl or CXX'X "wherein X, X', and X" are independently, C1-C20 alkyl, C1-C20 alkyl ether, C1 alkylamino -C20, C6-C10 aryl, substituted C1-C20 alkyl, or substituted C6-C10 aryl, and at least one of the substituents on Y or Y 'contains a tertiary amine group, except in formula A when R is methyl,? is - (CH2) XN (CH3) 2 or - (CH2) xN (CH2) and N (CH3) 2, x is 2 or 3, and y is 1, 2, or 3, and except in formula C when R and Y are each methyl, Y 'is - (CH2) XN (CH3) 2 and x is 1, 2' O 3. 5. The method according to the claim 1, characterized in that the cell opening additive comprises a compound represented by one of the formulas: wherein Y, Y ', Y "and Y' '', are independently, a substituted C6-C10 aryl or CXX 'X" wherein X, X', and X "are independently, Cl-C20 alkyl, C1-C20 alkyl ether, C1-C20 alkylamino, C6-C10 aryl, substituted C1-C20 alkyl or substituted C6-C10 aryl and at least one of the substituents on Y, Y "or Y '' ' , contains a tertiary amine group 6. The method according to claim 1, characterized in that the cell opening additive comprises a compound represented by one of the formulas: wherein Y and Y 'are, independently, substituted C6-C10 aryl or CXX'X "wherein X, X', and X" are, independently, C1-C20 alkyl, C1-C20 alkyl ether, C1 alkylamino -C20, C6-C10 aryl, substituted C1-C20 alkyl, or substituted C6-C10 aryl, and at least one of the substituents on Y or Y 'contains a tertiary amine group and D and D' are independently , electron attraction substituents such as N02, CN, F, Cl, Br, CF3, I, C (0) OR, C (0) R, CHO and C (0) NH2. The method according to claim 2, characterized in that one or both of Y and Y 'are selected from the group consisting of: in which R and R 'are, independently, C 1 -C 4 alkyl, n, n ', n "and n' '' are integers from 1 to 20, and R" and R '' 'are, independently, hydrogen, a C 1 -C 20 alkyl, an alkyl ether of C1-C20, a C1-C20 alkylamine, or a C1-C20 alkylthioether. The method according to claim 2, characterized in that one or both of Y and Y 'are derived from a member of the group consisting of 3- (dimethylamino) -propylamine, 3-dimethylamino-l-propanol, dimethylaminoethanol, trialkanolamines such as triethanolamine and tris (2-hydroxypropyl) amine, triaminoalkylamine, a 1-hydroxyalkylpyrrolidine, a 1-aminoalkylpyrrolidine, 1-hydroxyalkylimidazole, 1-aminoalkylimidazole 2- [N- (dimethylaminoethoxyethyl) -N-methyl-amino] ethanol and 2- [N-dimethylaminoethoxyethyl] -N-methylamino] -1-methylethanol, and tetramethyldiethylenetriamine, (CH3) 2NCH2CH2N (CH3) CH2CH2OH, [(CH3) 2NCH2CH2CH2] 2N (CH2CH2OH), [(CH3) 2NCH2CH2CH2] 2N (CH2CH (CH30H), N-hydroxyalkylmorpholine, an N-aminoalkylmorpholine, a hydroxyalkylpyrrolizidine, an aminoalkylpyrrolizidine, a hydroxyalkylnuclidine, an aminoalkylnuclidine, a hydroxyalkyltrietylenediamine, an aminoalkyltriethylenediamine and 3-quinuclidinol, wherein alkyl is Cl to C4 9. The method according to claim 3 characterized in that one or both of Y and Y 'are selected from the group consisting of: wherein R and R 'are, independently, C1-C4 alkyl, n, n', n "and n '' 'are integers from 1 to 20, and R" and R' '' are, independently, hydrogen, a C 1 -C 20 alkyl, a C 1 -C 20 alkyl ether, a C 1 -C 20 alkylamine, or a C 1 -C 20 alkylthioether. 10. The method of compliance with the claim 3 characterized in that one or both of Y and 'are derived from a member of the group consisting of 3- (dimethylamino) -propylamine, 3-dimethylamino-1-propanol, dimethylaminoethanol, trialkanolamines such as triethanolamine and tris (2-hydroxypropyl) amine , triaminoalkylamine, a 1-hydroxyalkylpyrrolidine, a 1-aminoalkylpyrrolidine, 1-hydroxyalkylimidazole, 1-aminoalkylimidazole 2- [N- (dimethylaminoethoxyethyl) -N-methyl-amino] ethanol and 2- [N-dimethylaminoethoxyethyl] -N-methylamino] - 1-methylethanol, and tetramethyldiethylenetriamine, (CH3) 2NCH2CH2N (CH3) CH2CH2OH, [(CH3) 2NCH2CH2CH2] 2N (CH2CH2OH), [(CH3) 2NCH2CH2CH2] 2N (CH2CH (CH3OH), N-hydroxyalkylmorpholine, N-aminoalkylmorpholine, hydroxyalkylpyrrolizidine, aminoalkylpyrrolizidine, hydroxyalkylnuclidine, aminoalkylnuclidine, hydroxyalkyltriethylenediamine, aminoalkyltriethylenediamine, and 3-quinuclidinol, wherein the alkyl is Cl to C4 11. The method according to claim 4 characterized in that one or more of Y, Y ', and Y "' ', are selected from the group consisting of: wherein R and R 'are, independently, C1-C4 alkyl, n, n', n "and n '' 'are integers from 1 to 20, and R" and R' '' are, independently, hydrogen, a C 1 -C 20 alkyl, a C 1 -C 20 alkyl ether, a C 1 -C 20 alkylamine, or a C 1 -C 20 alkylthioether. 12. The method according to claim 4 characterized in that one or more of Y, Y ', Y "and Y" are derived from a member of the group consisting of 3- (dimethylamino) -propylamine, 3-dimethylamino- l-propanol, dimethylaminoethanol, trialkanolamines such as triethanolamine and tris (2-hydroxypropyl) amine, triaminoalkylamine, 1-hydroxyalkylpyrrolidine, 1-aminoalkylpyrrolidine, 1-hydroxyalkylimidazole, 1-aminoalkylimidazole 2- [N- (dimethylaminoethoxyethyl) -N-methyl-amino ] ethanol and 2- [N-dimethylaminoethoxyethyl) -N-methylamino] -1-methylethanol, and tetramethyldiethylenetriamine, (CH3) 2NCH2CH2N (CH3) CH2CH2OH, [(CH3) 2NCH2CH2CH2] 2N (CH2CH2OH), [(CH3) 2NCH2CH2CH2] 2N (CH2CH (CH3OH), N-hydroxyalkylmorpholine, N-aminoalkylmorpholine, hydroxyalkylpyrrolizidine, aminoalkylpyrrolizidine, hydroxyalkylnuclidine, aminoalkylnuclidine, hydroxyalkyltriethylenediamine , aminoalkyltriethylenediamine, and 3-quinuclidinol, wherein alkyl is Cl to C4 13. The method according to claim 5 characterized in that one or both of Y, and Y ', are independently selected from the group consisting of: wherein R and R 'are, independently, C1-C4 alkyl, n, n', n "and n '' 'are integers from 1 to 20, and R" and R' "'are, independently, hydrogen, an alkyl of C1-C20, a C1-C20 alkyl ether, a C1-C20 alkylamine, or a C1-C20 alkylthioether. 14. The method according to the claim Characterized in that one or both of Y and Y 'are derived from a member of the group consisting of 3- (dimethylamino) -propylamine, 3-dimethylamino-1-propanol, dimethylethenoethanol, trialkanolamines such as triethanolamine and tris (2-hydroxypropyl) ) amine, triaminoalkylamine, 1-hydroxyalkylpyrrolidine, 1-aminoalkylpyrrolidine, 1-hydroxyalkylimidazole, 1-aminoalkylimidazole 2- [N- (dimethylaminoethoxyethyl) -N-methyl-amino] ethanol and 2- [N-dimethylaminoethoxyethyl] -N-methylamino] - 1-methylethanol, and tetramethyldiethylenetriamine, (CH3) 2NCH2CH2N (CH3) CH2CH2OH, [(CH3) 2NCH2CH2CH2] 2N (CH2CH2OH), [(CH3) 2NCH2CH2CH2] 2N (CH2CH (CH3OH), N-hydroxyalkylmorpholine, N-aminoalkylmorpholine, hydroxyalkylpyrrolizidine, aminoalkylpyrrolizidine, hydroxyalkylnuclidine , aminoalkylnuclidine, hydroxyalkyltriethylenediamine, aminoalkyltriethylenediamine, and 3-quinuclidinol, wherein the alkyl is Cl to C4 15. The method according to claim 6 characterized in that one or more of Y, and Y ', are independently selected from the group it consists of: wherein R and R 'are, independently, C1-C4 alkyl, n, n', n "and n '' 'are integers from 1 to 20, and R" and R' '' are, independently, hydrogen, a C 1 -C 20 alkyl, a C 1 -C 20 alkyl ether, a C 1 -C 20 alkylamine, or a C 1 -C 20 alkylthioether. The method according to claim 6 characterized in that one or both of Y and Y 'are derived from a member of the group consisting of 3- (dimethylamino) -propylamine, 3-dimethylamino-1-propanol, dimethylaminoethanol, trialkanolamines such as triethanolamine and tris (2-hydroxypropyl) amine, triaminoalkylamine, 1-hydroxyalkylpyrrolidine, 1-aminoalkylpyrrolidine, 1-hydroxyalkylimidazole, 1-aminoalkylimidazole 2- [N- (dimethylaminoethoxyethyl) -N-methyl-amino] ethanol and 2- [N- dimethylaminoethoxyethyl) -N-methylamino] -1-methylethanol, and tetramethyldiethylenetriamine, (CH3) 2NCH2CH2N (CH3) CH2CH2OH, [(CH3) 2NCH2CH2CH2] 2 (CH2CH2OH), [(CH3) 2NCH2CH2CH2] 2N (CH2CH (CH3OH), N- hydroxyalkylmorpholine, N-aminoalkylmorpholine, hydroxyalkylpyrrolizidine, aminoalkylpyrrolizidine, hydroxyalkylnuclidine, aminoalkylnuclidine, hydroxyalkyltriethylenediamine, aminoalkyltriethylenediamine, and 3-quinuclidinol, wherein the alkyl is Cl to C4 17. The method according to claim

1, characterized in that the cell-opening additive is 2-cyano-N- [3- (dimethylamino) propyl] acetamide. 18. The method according to claim 1, characterized in that the cell-opening additive is (NC) CH2C (O) OCH2CH2N (CH3) CH2CH2OCH2CH2N (CH3)

2.