AN ACTIVE HYDROGEN-CONTAINING COMPOSITION CONTAINING A DIALKANOL TERTIARY AMINE AND A PROCESS FOR PREPARING A POLYURETHANE FOAM

Abstract: Active hydrogen-containing composition and a process for preparing a polyurethane foam using said composition. The active hydrogen-containing composition comprises (a) at least one polyahl having at least three active hydrogens per molecule and which is not a dialkanol tertiary amine, (b) a minor amount of water, and (c) a dialkanol tertiary amine present in an amount sufficient to improve the flowability of a foaming reaction mixture prepared from the active hydrogen-containing composition and a polyisocyanate, characterized in that the isocyanate-reaction materials present in said active hydrogen-containing composition have an average functionality of at least 3.0. The compressive strength of rigid foams prepared by the process of this invention is generally equal or superior to rigid foams prepared by previously known compositions.

Description: AN ACTIVE HYDROGEN-CONTAINING COMPOSITION CONTAINING A DIALKANOL TERTIARY AMINE AND A PROCESS FOR PREPARING A POLYURETHANE FOAM This invention relates to an active hydrogen- -containing composition containing a dialkanol tertiary amine and to a process for preparing polyurethane foams, especially rigid foams. Rigid polyurethane foams are commonly used for thermal insulation in refrigerators, freezers, roofs, walls, and the like. These polyurethane foams 'are often preferred over other types of insulation due to their ability to be formed in situ by reacting and foaming a polyurethane reaction mixture in the space where insula¬ tion is desired. The resulting rigid foam exhibits good thermal insulation properties (sometimes expressed as a low K factor or thermal conductivity) and often provides some structural support as well. Because of the manner in which such foams are prepared, it is important that the foaming reac- tion mixture be capable of completely filling the available space before the polymerization reaction is completed. The ability of the reaction mixture to fill a mold is generally referred to as "flow- ability". It is generally desirable that the reac¬ tion mixture exhibit good flowability. However, it is often difficult to obtain good flowability in the preparation of polyurethane and/or polyurea ' foam. To improve the flowability of the foaming reaction mixture it is known to incorporate small amounts of water into the polyol. The water, how- ever, causes the resulting rigid foam to have gener¬ ally poorer insulating properties. In addition, the compressive strength of the foam is often wors¬ ened by having water in the polyol. Thus, the prac¬ titioner has often been forced to choose between having-good insulation capacity and strength on the one hand, or good flowability on the other. British Patent 981,135 relates to the use of N-substituted dialkanolamines in conjuction with polyethers containing at least two hydroxyl groups and two ether linkages for the manufacture of foamed cellular polyurethane materials. U.S. Patent 4,339,343 discloses polyol blends comprising an amine diol and a primary hydroxyl polyol. These blends are useful for the preparation of polyiso- cyanurate foams. In addition to having good flowability, the foam prepared from the reaction mixture disirably exhibits little shrinkage upon curing and subsequent cooling. In commercial practice, it is often necessary to use a greater amount of the reaction mixture than is theoretically required to fill a mold in order to prevent subsequent foam shrinkage at cold temperatures. This excess amount is often expressed as "percent packing", this ratio of the excess required to prevent shrinking at low temperatures to the minimum amount of reaction mixture required to barely fill the mold. It is obviously beneficial to reduce the percent packing, as this reduces the quantity of raw materials required. It would be desirable to provide a polyol composition which provides good flowability to the foaming reaction mixture and which also produces, upon reaction with a polyisocyanate, a polyurethane and/or polyurea foam with good thermal insulating properties. It is further desirable to provide a foam requiring a small percent packing. In addition, it would be desirable to provide a rigid polyurethane foam which also has good compressive strength. This invention is an active hydrogen- -containing composition comprising (a) at least one polyahl having at least three active hydrogens per molecule which is not a dialkanol tertiary amine, (b) a minor amount of water and (c) a dialkanol tertiary amine in an amount sufficient to improve the flowability of a foaming reaction mixture prepared from the active hydrogen-containing composition and a polyisocyanate, characterized in that the isocyanate-reactive materials present in said active hydrogen-containing composition have an average functionality of at least 3.0. This invention is also a process for pre¬ paring a polyurethane foam by reacting a polyisocyanate and an active hydrogen-containing composition compris¬ ing (a) at least one polyahl having at least three active hydrogens per molecule and which is not a dial¬ kanol tertiary amine, (b) a minor amount of water, and (c) a dialkanol tertiary amine present in an amount sufficient to improve the flowability of a foaming reaction mixture prepared from the active hydrogen- -containing composition and a polyisocyanate char¬ acterized in that the isocyanate-reactive materials present in said active hydrogen-containing composition have an average functionality of at least 3.0. The active hydrogen-containing composition of the invention, when reacted with a polyisocyanate to form a rigid polyurethane foam, provides a foam having a K-factor which is comparable or lower than those obtained with previously known foam formulations which do not contain the dialkanol amine. In addition, the compressive strength of.rigid foams prepared according to the invention is generally equal or superior to those prepared according to previously known composi¬ tions. Thus, with this invention, the practitioner is not forced to trade off strength or insulation capacity for flowability. This invention further provides for a low percent packing. In this invention, a dialkanol tertiary amine is used in an active hydrogen-containing composition which comprises a polyahl and water. The dialkanol tertiary amine used in this invention contains a tertiary nitrogen atom to which are attached two aliphatic hydroxyl groups. This dialkanol tertiary amine is represented by the structure R-N- (R ' OH) 2 wherein R is an inertly substituted organic radical and each R' is independently an inertly substituted alkylene, alkyl ether or poly(alkylether) radical. By "inertly substituted, " it is meant that the moiety referred to contains no substituent group which reacts with or adversely interferes with the reaction of the ' active hydrogen containing composition and the polyisocyanate to form a polyurethane foam. The group R is advantageously an alkyl, cycloalkyl, aryl, aralkyl, alkyl ether, or alkyl terminated poly(oxyalkylene) group. Suitable alkyl groups include those having from 1 to 22 carbon atoms, including both linear and branched species. Such alkyl group may contain cycloalkyl or aryl substituent groups, as well as sites .of unsat- uration and inert substituent groups such as, for example, halogen, ether, or tertiary amine. Prefer¬ ably, the alkyl group contains from 1 to 8, more preferably from 1 to 4 carbon atoms. Suitable cycloalkyl groups include those having from 4 to 8 carbon atoms in the ring, includ¬ ing, for example, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl groups. The ring may contain inert substituents such as, for example, alkyl, halo¬ gen or alkoxy groups as well as sites of unsaturation. Suitable aryl groups include, for example, phenyl, naphthyl, tolyl, xylyl, and methylnaphthyl, as well as those containing various inert substituents such as, for example, halogen, alkyl, and alkoxyl. Suitable aralkyl groups include, for example, benzyl, naphthylme hylene, and tolyl methylene as well as those containing inert substituents such as, for example, halogen, alkyl, and alkoxyl. Suitable alkylether and organic-terminated poly(oxyalkylene) groups include, for example, me hoxy- ethylene, ethoxyethylene, methoxy-2-methyl ethylene, ethoxy-2-methyl ethylene, CH 3 (OC 2 H 4 )-^, and C 2 H 5 (OC 2 H 4 )^. The R' group is advantageously alkylene, inertly substituted alkylene, alkyl ether or poly- oxyalkylene having from 2 to 12, preferably from 2 to 4 carbon atoms. The R' group may be straight chained or branched. Preferred as the R* group are alkylene radicals, especially ethylene, 2-methyl ethylene and 2-ethyl ethylene radicals, with the 1 carbon atom being that attached to the nitrogen atom. Exemplary dialkanol tertiary amines suitable herein include methyl diethanol amine, ethyl diethanol amine, isopropyl diethanol amine, n-propyl diethanol amine, n-, iso-, or t-butyl diethanol amine, methyl di(2-isopropanol) amine, ethyl di(2-isopropanol) amine, isopropyl 2-di(2-isopropanol) amine, cyclo- hexyl diethanol amine, cyclohexyl di(2-isopropanol) amine, phenyl diethanol amine, phenyl di(2-isopropanol) amine, benzyl diethanol amine, and benzyl di(2-isopropanol) amine. Preferred are the di(ethanol) tertiary amines, especially the alkyl diethanol amines, and most prefer¬ ably methyl diethanol amine. Also suitable as the dialkanol tertiary amine are the reaction products of a primary amine and from 2 to 20, preferably from 2 to 6, moles of an alkylene oxide. The dialkanol tertiary amine is present in an amount sufficient to improve the flowability of a foaming reaction mixture prepared with the active hydrogen-containing composition and a polyisocyanate. In addition, the amount of the dialkanol tertiary amine is such that an active hydrogen-containing composition containing same has an average functionality (based on • the isocyanate-reactive materials therein) of at least 3.0. Generally the dialkanol tertiary amine is a minor component of the active hydrogen containing composition. Advantageously the dialkanol tertiary amine is used in an amount from 3 to 40, preferably from 3 to 20, more preferably from 3 to 15 parts by weight per 100 parts by weight of the polyahl(s) contained in the active hydrogen-containing composition. "Flowability" is a term used to express the ability of a reacting polyahl-polyisocyanate mixture to expand and fill a mold. This property is quite • important for "foamed in place" foams, where the ability of a foaming mixture to completely fill its container, which may be complexly shaped, is critical. The ability of the reacting mixture to fill a mold depends on several factors, including the relative rates of the polymeri¬ zation reaction and the evolution of gases in the mixture, the viscosity and density of the reactants, the amount of crosslinkages formed in the reaction, and the like. Flowability is measured by injecting a premixed polyahl mixture and polyisocyanate into a 6'6" x 8" x 2" (2.0 m x 0.2 m x 51 mm) mold at 125 ±5°C. An amount of the reactants is chosen such that, upon expanding, it just fills the mold, (i.e. about 0 per¬ cent packing) . The mold is held in a vertical position (i.e. 6'6" (2.0 m) rise direction) and the foaming polymer is allowed to expand against its own weight in the mold. After the foam has risen and reacted, the density of the foam is measured to determine flow- ability. A lower density indicates better flowability. In this invention, flowability is generally improved by from 2 to 40 percent, preferably from 5 to 20 percent compared to a like foam prepared in the absence of the dialkanol tertiary amine. The active hydrogen containing composition of this invention contains at least one compound which is not a dialkanol tertiary amine having three or more active hydrogen atoms. For the purpose of this inven¬ tion, the term "polyahl" refers to a moiety containing at least two hydrogen atoms which, because of their position in the molecule, display significant activity according to the Zerewitnoff test described by Woller in the Journal of American Chemical Society, Vol. 49, page 3181 (1927). Illustrative of such active hydrogen moieties are -COOH, -OH, -NH 2 , -NH-, -C0NH 2 , -SH and -CONH-. Typical polyahls include polyols, polyamines, polyamides, polymercaptans and polyacids. In general, polyols and polyamines are preferred. Polyols are most preferred. It is noted that when a polyamine is used herein, its reaction with a polyisocyanate results in the formation of a urea linkage. The terms "urethane" and "polyurethane," as used herein, include those reaction products of a polyisocyanate with any of the polyahls described herein. The polyahl employed may have any equivalent weight and any number of active hydrogen atoms which is suitable for preparing a foam having the desired properties, provided that the average functionality of the isocyanate-reactive materials in the active hydro¬ gen containing composition is at least 3.0. The pro- duction of flexible foams is generally favored by using a relatively high equivalent weight polyahl and/or one having relatively few active hydrogen atoms per molecule. To produce a flexible foam, a polyahl having an equiva¬ lent weight from 500 to 5,000, preferably from 1000 to 3000, is advantageously employed. Such polyahl also most advantageously has an average of from 3 to 4 active hydrogen atoms per moelcule. This invention is generally most advantageous in the production of rigid polyurethane foams, and a polyahl which gives rise to such a rigid foam is pre¬ ferred. The formation of rigid polyurethane foams is generally favored by the use of a relatively low equiva¬ lent weight polyahl having at least 3 active hydrogens. To prepare rigid foams, at least a portion of the polyahl used advantageously has a hydroxyl equivalent weight from 50 to 300, preferably from 70 to 200, more preferably from 70 to 150. This low equivalent weight polyahl also preferably contains at least 3 active hydrogens and more preferably from 4 to 8 active hydro¬ gens. Generally, when such low equivalent weight polyahl, or a polyahl having at least three active hydrogens is used, it comprises at least 50 percent, preferably 60 to 95 percent, by weight of the polyahls employed in the active hydrogen-containing composition. In addition, or alternatively, difunctional and/or high equivalent weight polyahls can be used in the preparation of rigid foams. Preferably, however, such difunctional and/or higher equivalent weight polyahls comprise a minor portion, preferably 50 per¬ cent or less, more preferably from 5 to 40 percent, most preferably from 5 to 15 percent of the combined ' weight of the polyahls, and the average functionality of the isocyanate-reactive materials in the reaction mixture must be at least 3.0. Suitable polyahls include polyether polyols, polyester polyols, polyhydroxyl-containing phosphorous compounds, hydroxyl-terminated acetal resins, hydroxyl terminated amines and polyamines, the corresponding amine-terminated polyether and/or polyester polyols, the so-called polymer or copolymer polyols which com- • prise a dispersion of an addition polymer as copolymer in a continuous polyahl phase, as well as other active hydrogen-containing compounds which are known to be useful in the preparation of urethane polymers. Examples of these and other suitable polyahls are described more fully in U.S. Patent No. 4,394,491, particularly in columns 3-5 thereof. Suitable copolymer polyols include those described in U.S. Patent No. Re 29,118 and Re 28,715 and 4,394,491. Most preferred for preparing rigid foams, on the basis of performance, availability and cost, is a polyether polyol prepared by adding an alkylene oxide to an initiator having from 3 to 8, preferably from 4 to 8 hydroxyl groups. Exemplary such polyether polyols include those commercially available under the trade names Voranol 202, Voranol 360, Voranol 370, Voranol 446, Voranol 490, Voranol 575, Voranol 800, sold by The Dow Chemical Company, and Pluracol 824, sold by BASF Wyandotte. Water is another critical component of the active hydrogen-containing composition. The water is necessary to improve the flowability of the foaming reaction mixture and also reacts with isocyanate groups to generate carbon dioxide. In the past, the use of water has caused the resulting polyurethane foam to have less than desirable compressive strength and/or higher K factor (thermal conductivity). Due to the use of the dialkanol tertiary amine herein, such problems are minimized or overcome. Water is generally a minor component of the active hydrogen containing composition, and is used in an amount sufficient to improve the flowability of a foaming reaction mixture prepared from the active hydrogen containing composition and a polyisocyanate. Advantageously, from 0.1 to 5, preferably from 1 to 4, more preferably from 1 to 3 parts by weight water are used per 100 parts by weight of polyahl. Optionally, but preferably, an auxilliary blowing agent in addition to water is also present in the active hydrogen-containing composition of the invention. Suitable blowing agents include inert gases, low boiling organic compounds and other com¬ pounds which evolve a gas under the conditions of the reaction between the polyahl and a polyisocyanate. Preferably, the blowing agent is a low-boiling organic compound, especially a halogenated hydrocarbon such as a fluorocarbon. Most preferred for preparing rigid foa s, due to their suitable boiling temperatures, are fluorocarbons such as, for example, tetrafluoromethane, trifluorochloromethane, and dichlorodifluoromethane. Such fluorocarbons also remain in the cells of rigid polyurethane foam and contribute to the insulating -properties thereof. Methylene chloride is preferred in preparing flexible foams. The blowing agent, along with the water, is used to provide a cellular structure to the foam, and is used in an amount sufficient for this purpose. Advantageously, from 5 to 100, prefer¬ ably from 20 to 60 parts by weight of blowing agent are present per 100 parts by weight of polyahl. In addition to the foregoing components, the active hydrogen-containing composition may optionally contain such conventional additives such as, for example, surfactants, catalysts for the polymerization .(chain extension) and blowing (foaming) reactions as described hereinafter, .pigments, fillers, flame retardants, or stabilizers. As mentioned hereinbefore, the active hydro¬ gen containing composition has an average functionality of at least 3.0. The average functionality is based on the isocyanate-reactive components in the composition including the polyahl, water and the dialkanol tertiary amine. The term "functionality" refers to the number of active hydrogens per molecule of isocyanate reactive material. When the average functionality is below 3.0, the cured foam prepared therefrom tends to shrink at cold temperatures. This shrinkage is conventionally • overcome by filling the mold with an excess of reac¬ tants over that minimally necessary to fill the mold. The excess which is necessary to prevent this shrinkage is often referred to as "percent packing". It has been found that when the average functionality of the active hydrogen-containing composition is less than 3.0, the percent packing is unacceptably high. In other words, a lower functionality tends to increase shrinkage in the foam at lower temperatures. Thus, this invention provides for a desirably low percent packing, as well as excellent flowability and K-factor (thermal conduc¬ tivity) . In the improved process of this invention, a rigid polyurethane foam is prepared by reacting a polyahl as described hereinbefore with a polyisocyanate in the presence of water and a dialkanol tertiary amine in the amounts described hereinbefore. The conditions and procedures employed are those conventionally employed in making rigid polyurethane foams. Suitable conditions and procedures are disclosed in U.S. Patent No. RE 24,514. Although each of the foregoing components may be added separately to the reaction mixture, it is normally preferred to add them in as few streams as possible. It is normal practice to combine all of the components except the polyisocyanate together and add them in a single stream. Organic polyisocyanates which may be employed include aromatic, aliphatic and cycloaliphatic poly¬ isocyanates and combinations thereof. Representative of these types are diisocyanates such as m-phenylene diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,- 6-diisocyanate, hexamethylene-1,6-diisocyanate, tetra- methylene-1, -diisocyanate, cyclohexane-1,4-diisocyanate, hexahydro olylene diisocyanate (and isomers), naphthylene-1,5-diisocyanate, l-methoxyphenyl-2,4- diisocyanate, diphenylmethane-4,4'-diisocyanate, 4,- 4'-biphenylene diisocyanate, 3,3 '-dimethoxy-4,4'- -biphenyl diisocyanate, 3,3'-dimethyl-4,4'-diphenyl- diisocyanate, and 3,3'-dimethyldiphenylpropane-4,4' ,- 4'-diisocyanate; the triisocyanate polymethylene polyphenylisocyanate and tolylene-2,4,6-triisocyanate; and the tetraisocyanates such as 4,4'-dimethyldiphenyl- methane-2,2' ,5,5'-tetraisocyanate. A crude polyisocyanate may also be used in the practice of the present invention, such as the crude toluene diisocyanate obtained by the phosgenation of a mixture of toluene diamines or the crude diphenyl- methylene diisocyanate obtained by the phosgenation of crude diphenylmethylenediamine. The preferred undistilled or crude isocyanates are disclosed in U.S. Patent No. 3,215,652. Especially preferred are methylene bridged polyphenylpolyisocyanates, due to their ability to crosslink the polyurethane. The isocyanate index (ratio of equivalents of isocyanates to equivalents of active hydrogens) is advantageously from 0.90 to 10, preferably from 1.0 to 4.0, and more preferably from 1.0 to 1.25. The urethane reaction of a polyisocyanate , with the active hydrogen containing composition is advantageously carried out in the presence of an amount of urethane-type catalyst which is effective to catalyze the reaction of the polyahl with the polyisocyanate. Preferably, the amount of urethane catalyst is that amount conventionally used in conventional urethane- -type reactions. It is noted that the dialkanol ter¬ tiary amine itself exhibits catalytic activity, and may effect the amount of other catalyst needed. Any suitable urethane catalyst may be used including tertiary amines, such as, for example, tri- ethylenediamine, N-methyl morpholine, N-ethyl morpho- line, diethyl ethanolamine, N-coco morpholine, 1-methyl- -4-dimethylaminoethyl piperazine, 3-methoxy-N-dimethyl- propyl amine, N,N-dimethy1-N' ,N'-methyl isopropyl propylenediamine, N,N-diethyl-3-diethylaminopropyl amine, and dimethyl benzyl amine. Other suitable catalysts are, for example, tin compounds such as stannous chloride, tin salts of carboxylic acids such as dibutyltin di-2-ethyl hexoate, as well as other organometallic compounds such as are disclosed in U.S. Patent No. 2,846,408. A catalyst for the trimerization of polyisocyanates, such as an alkali metal alkoxide, may also optionally be employed herein. A wetting agent(s) or surface-active agent(s) is generally necessary for production of high grade polyurethane foam according to the present invention, since in the absence of same, the foams collapse or contain very large, uneven sized cells. Numerous wetting agents have been found to be satisfactory. Nonionic surfactants and wetting agents are preferred. Of these, the nonionic surface-active agents prepared by the sequential addition of propylene oxide and then ethylene oxide to propylene glycol and the solid or liquid organosilicones have been found particularly desirable. Other surface-active agents which are operative, although not preferred include polyethylene glycol ethers of long chain alcohols, tertiary amine or alkylolamine salts of long chain alkyl acid sulfate esters, alkyl sulfonic esters and alkyl arylsulfonic acids. The following examples are given to illus¬ trate the present invention and are not to be construed as limiting the scope thereof in any manner. All parts and percentages are by weight unless otherwise indi¬ cated. Example 1 and Comparative Run A An active-hydrogen containing composition according to this invention (Sample No. 1) is prepared by mixing together the following ingredients: Parts by Weight Voranol* 370 1 * 88.5 Polyglycol P-1200 2 11.5 Water 3.0 Surfactant 3 1.75 Dimethylcyclohexyl amine 1.9 Methyl diethanol amine 15.0 Dibutyltindilaurate 0.08 Freon ll 4 23% by weight of polyols plus polyisocyanate Average functionality 3.07 x A poly(propylene oxide) polyol having a function¬ ality between 6 and 7 and an equivalent weight of 150. 2 A 1200 molecular weight polypropylene glycol. 3 A liquid organosilicone surfactant. 4 Trichloromonofluoromethane. This composition is reacted with a methylene- bridged polyphenyl polyisocyanate (commercially available under the brand name Rubinate M) at a 1.05 isocyanate index. The reactants are mixed and delivered on a Martin-Sweet Flex 30 foam machine. The temperature of each reactant is 70°F (21°C). The throughput of foam is 29 lb/rαin. (0.22 kg/s). Flowability is measured according to the procedure described hereinbefore. A portion of the polymer is injected into a 2'x2'x2" (0.6 m x 0.6 m x 51 mm) panel mold which is preheated to 140°F (60°C). The polymer is allowed to rise and fill the mold. The resulting foam is evaluated for density, compressive strength (in parallel and perpendicular to rise direc- tions) abrasion loss and K factor (thermal conductivity). The results are reported in Table I following. For comparison, an active hydrogen-containing composition like that used to prepare Example 1, except that it contains no dialkanol tertiary amine, is pre- pared and used to make a polyurethane foam in the same manner as Example 1. The properties of this foam, designated Comparative Run A, are reported in Table 1 following. TABLE I Example 1 Comparative Run A* Density, pcf (kg/m 3 ) 1.73 (27.71) 1.70 (27.23) Compressive Strength, psi (kPa) perpendicular direction 12.19 (84.05) 8.50 (59.37) parallel direction 18.94 (130.59) 14.13 (97.42) Abrasion, wt. loss (%) 1.5 6.6 Flowability, pcf (kg/m 3 ) 1.40 (22.43) 1.73 (27.71) Thermal Conductivity, 0.124 0.147 BTU/h*ft*°F (W/m-k) (0.215) (0.254) As can be seen from the results in Table I, the addition of a dialkanol tertiary amine provides substantial improvement in compressive strength, abrasion resistance, flowability and K-factor (thermal conductivity) at an equivalent foam density. * Example 2 and Comparative Run B An active hydrogen containing composition is prepared by blending the following components: -19- Parts by weight Voranol* 370 1 70 Polyol XAS 10797 2 30 Water 2.5 Surfactant 3 1.75 dimethyl cyclohexyl amine 2.70 Dibutyltindilaurate 0.08 Freon ll 4 22% by weight of polyols plus polyisocyanate methyldiethanolamine 5.0 Average functionality 3.43 1 A poly(propylene oxide) polyol having a functionality between 6 and 7 and an equivalent weight of 150. 2 An experimental amine initiated polyol, tetrafunc- tional, having an equivalent weight of 165. 3 A liquid organosilicone surfactant 4 Trichloromonofluoromethane A polyurethane foam is prepared from this composition using the polyisocyanate and process described in Example 1. The resulting foam is tested as described in Example 1. The results obtained are reported as Example 2 in Table II following. For comparison, an active hydrogen containing composition, Comparative Run B, is prepared which is the same in all respects except no dialkanol tertiary amine is used. The composition is foamed as in Example 2. The properties of a foam prepared from Comparative Run B are reported in Table II. TABLE II Example 2 Comparative Run B Density pcf (kg/m 3 ) 1.72 (27.55) 1.67 (26.75) Compressive strength psi (kPa) perpendicular direction 11.56 (79.70) 9.56 (65.91) parallel direction 19.69 (135.76) 19.63 (135.34) Abrasion, wt loss % 3.14 4.78 Flowability, pcf (kg/m 3 ) 1.55 (24.83) 1.68 (26.91) Thermal Conductivity 0.136 0.141 BTU/h « ft*°F(W/m-k) (0.235) (0.244) Again, improvement in K-factor (thermal conduc¬ tivity), flowability, compressive strength and abrasion weight loss are seen when a dialkanol tertiary amine is present in the reaction mixture. Examples 3 to 6 : Active hydrogen containing composition, Examples 3 to 6, are each prepared from the following- base formula¬ tion: -21- Voranol 370 1 82.3 parts P-1010 2 10.7 parts Water 3.0 Surfactant 3 1.75 Dimethylcyclohexyl amine Dibutyltindilaurate 0.08 Freon ll 4 23% by weight of polyols plus polyisocyanate Dialkanol tertiary amine x A poly(propylene oxide) polyol having a functionality between 6 and 7 and an equivalent weight of 150. 2 A 1200 molecular weight polypropylene glycol. 3 A liquid organosilicone surfactant, 4 Trichloromonofluoromethane. The amount and type of dialkanol amine employed in each of Examples 3 to 6 are indicated in Table 3. ' Each of Examples 3 to 6 are reacted with the polyisocy¬ anate described in Example 1 at a .1.05 index. The flowability, density, compressive strength, abrasion loss and K factor (thermal conductivity) are measured for each of the resulting foams, with results as indicated in Table III. Table V Example or Comparative Run D Compressive Strength psi (kPa) perpendicular direction 13.3 (91.70) 13.4 (92.39) 12.2 (84.12) parallel direction 17.9 (123.42) N.D. 18.9 130.31 Thermal Conductivity, 0.130 0.130 0.127 BTU/h*ft-°F, (w/m*k) (0.225) (0.225) (0.220) Flowability pcf (kg/m 3 ) 1.34 (21.46) 1.41 (22.59) 1.41 (22.59) Percent packing 35 32 25 N.D. not determined. -23- Exam le 7 and Comparative Runs C and D This example illustrates the effect of func¬ tionality on shrinkage. Comparative Runs C and D and Example 7 are prepared according to the general method described in Example 1, using the components disclosed in Table IV following. Table IV Parts by Weight Comp. Comp. Example Component Run C Run D 7 Voranol* 370 1 67.50 73.80 76.95 Polyglycol P-1200 2 15.85 9.50 10.00 Methyldiethanol amine 16.66 16.70 13.05 Surfactant 3 1.75 1.75 1.75 Dimethylcyclohexyl amine 1.82 1.90 l.;90 Dibutyltin dilaurate 0.08 0-.04 0.04 - Freon ll 4 63.0 58.0 58.0 Water 3.0 3.0 3.0 Polymeric MDI 105 105 105 Functionality 5 2.83 2.91 3.10 1 A poly(propylene oxide) polyol having a functionality between 6 and 7 and an equivalent weight of 150. 2 A 1200 molecular weight polypropylene glycol. 3 A liquid qrganosilicone surfactant. 4 Trichloromonofluoromethane. 5 Average functionality of all isocyanate-reactive materials. Properties of the resulting foams are evaluated as described in Example 1 and reported in Table V. Percent packing is calculated in each case by finding the minimum density foam which does not shrink at 0°C, subtracting the flowability, and dividing the difference by the flowability. A lower percent packing is preferred. TABLE III Example Dialkanol tertiary phenyl diethanol coco diethanol o-tolyl ethyl diethanol amine type amine amine diethanol amine amine Parts 10.7 16.5 11.2 7.2 Average Functionality, 3.22 3.24 3.21 3.44 Isocyanate-reactive materials Density pcf (kg/m 3 ) 1.72 (27.55) 1.67 (26.75) 1.75 (28.03) 1-70 (27.23) Compressive Strength, psi (kPa) perpendicular direction 13.1 (90.32) 10.5 (72.39) 11.7 (80.67) 12.1 (83.43) parallel direction 19.4 (133.76) 16.2 (111.70) 18.9 (130.31) 20.6 (142.03) Abrasion wt loss, % 3.84 2.88 3.82 3.50 Flowability, pcf (kg/m 3 ) 1.55 (24.83) 1.49 (23.87) 1-52 (24.35) 1.51 (24.19) Thermal Conductivity, 0.130 0.141 0.134 0.131 BTU/h-fT-°F(W/m*k) (0.225) (0.244) (0.232) (0.227) Excellent flowability, compressive strength and K-factor are seen in each of these foams, particularly when contrasted with the properties of Comparative Run A. By comparing Example 7 with the Comparative Runs, it is seen that the higher average functionality of the isocyanate reactive materials provides a lower K factor (thermal conductivity) and significantly less shrinkage, as indicated by the lower percent packing.

Claims: CLAIMS 1. An active hydrogen containing composition comprising (a) at least one polyahl having at least three active hydrogens per molecule which is not a 5 dialkanol tertiary amine, (b) a minor amount of water, and (c) a dialkanol tertiary amine present in an amount sufficient to improve the flowability of * 10 a foaming reaction mixture prepared from the active hydrogen-containing composition and a polyisocyanate characterized in that the isocyanate reactive materials present in said active hydrogen-containing composition have an average functionality of at least 3.0. 15 2. The active hydrogen-containing composi¬ tion of Claim 1 characterized in that the polyahl com¬ prises a major portion of a low equivalent weight polyahl having an equivalent weight from about 50 to 300. 3. The active hydrogen-containing composi¬ tion of Claim 1 characterized in that the dialkanol tertiary amine is used in an amount from 3 to 40 parts by weight per 100 parts by weight of polyahl. 4. The active hydrogen-containing composi¬ tion of Claim 1 characterized in that the dialkanol tertiary amine is an alkyl dialkanol amine. 5. The active hydrogen-containing composi¬ tion of Claim 4 characterized in that the dialkanol tertiary amine is methyl diethanol amine or ethyl diethanol amine. 6. A process for preparing a polyurethane foam by reacting a polyisocyanate and an active hydrogen- -containing composition comprising (a) at least , one polyahl having at least three active hydrogens per molecule and which is not a dialkanol tertiary amine, (b) a minor amount of water, and (c) a dialkanol tertiary amine present in an amount sufficient to improve the flowability of a foaming reaction mixture prepared from the active hydrogen-containing composi¬ tion and a polyisocyanate, characterized in that the isocyanate-reactive materials present in said active hydrogen-containing composition have an average functionality of at least 3.0. 7. The process of Claim 6 characterized in that the reaction is conducted in the presence of an auxiliary blowing agent. -29- 8. The process of Claim 6 characterized in that the dialkanol tertiary amine is used in an amount from 3 to 40. parts by weight per 100 parts by weight of polyahl. 5 9. The process of Claim 8 characterized in that the dialkanol tertiary amine is an alkyl dialkanol amine. 10. The process of Claim 9 characterized in that the alkyldialkanol amine is methyl diethanol 10 amine or ethyl diethanol amine.

Inventors: NICHOLS JERRAM B, NICHOLS, JERRAM, B.
Applicants: DOW CHEMICAL CO, THE DOW CHEMICAL COMPANY
Application year: 1985
Main classification: C08G18
IPC codes: C08G18