MXPA01002741A - Low resilience, low frequency molded polyurethane foam - Google Patents

Abstract

Molded polyurethane seating foams exhibiting low resonant frequencies and low ball rebound are produced by reacting an isocyanate-terminated prepolymer prepared from a polyol component comprising in major part one or more low intrinsic unsaturation substantially polyoxypropylene polyols and/or polymer polyols with a blowing/chain extending stream comprising water and optionally amines and alkanolamines.

Description

MOLDED POLYURETHANE FOAM OF LOW FREQUENCY Tf OF LOW ELASTICITY.

TECHNICAL FIELD The present invention relates to low-resonance, low-rebound ball polyurethane foams and suitable formulations for their preparation. The foams are useful in applications for dynamic seats, and are made by introducing a low isocyanate prepolymer of low intrinsic unsaturation and a foam former and a water flow that extends in a chain in a mold and allowing the reactive system to foam and cure.

Description of the Related Art Molded polyurethane foams have managed to dominate in vehicle seat cushions. The principle of modern vehicle design dictates the minimization of the weight of the component and the cost. Since weight and cost represent a very important point for vehicle seats, it is not surprising that permanent efforts have been made to improve these components, and if possible reduce their cost, while maintaining or improving passenger comfort. .

REF. DO NOT. 127537 a ______ i ________ fi ______? __ aaí _____ ii ____ ^ _____________ f Ü g £ In the past, a composite car seat with a spring suspension and a molded polyurethane foam cushion has been common. However, the additional desire to reduce weight while also improving the recyclability of vehicle components has led designers to consider "foam base" or "total foam" designs where the spring suspension is removed. In the spring-loaded suspension seat, both the spring suspension and the foam cushion are useful for isolating passengers from the vibration of the vehicle, whether it is induced by the vehicle itself, ie the vibration of the engine, or by Your trip on the road. The elimination of the spring suspension requires the foam pad itself to absorb or attenuate all physiologically active vibrations, mainly those in the range of 6 Hz to 20 Hz. A discussion of these problems and the applicability of three molded foam systems of urethane, TDI HR, hot curing of TDI, and MDl HR, in the absorption / attenuation of vibration is documented in M. Kinkelaar, KD Cavender, and G. Crocco, "Vibrational Characterization of Various Polurethane Foams Employed in Automotive Seating Applications". Proceeding from the Polyurethanes Expo conference? 96, Division of Polyurethane, SPI, pp. 496-503 (1996), incorporated herein by reference. According to Kinkelaar and collaborate, the comfort of the seat of the vehicle is improved with the reduction in transmission of vibration of the foam or seat in the region 6-20 Hz. Generally, the laboratory vibration test of the seat foam does not predict with absolute precision the performance of the foam in the vehicle. However, studies indicate that the foam vibration test correlates with comfort in the vehicle, and foams with natural low frequencies in the test lab tend to provide improved vibration control in the vehicle. Generally, the results of laboratory vibration tests for the seat foam are a nonspecific test method. The test methods employed herein are described in more detail in the specification. The normal performance of a laboratory vibration test is a plane of transmissivity versus frequency, where the transmissivity is defined as the peak response acceleration (A) divided by the peak input acceleration (A0). The most common plane contains three different regions. At very low frequencies (Region 1), A / A0 = 1, and the response vibration equal to the input vibration. At higher frequencies (Region 2), the response vibration exceeds the input vibration (A / A0> 1). For the test method used in it, the vibration peaks of 5 response to the natural frequency. At even higher frequencies (Region 3), the response vibration and the A / AD slope value below 1. Region 3 is the "attenuation" region. These are the attenuation properties of greatest interest to the experts in the technique. As is also known in the art, the natural frequency is inversely related to the ball bounce. In other words, foams with high ball bounce tend to have more natural frequencies casualties, and vice versa. The automotive seating industry recognizes that a low natural frequency is needed for excellent vibrational comfort e? a seat of total foam. Accordingly, the high ball bounce foam for full foam seat applications. However, the high ball bounce can lead to other problems. For example, when the entrance vibration of the road approaches the natural frequency of the automotive seat, this vibration It is amplified, which leads to passenger discomfort and potential safety concerns. The trends discussed by Kinkelaar and collaborators are also evidenced by patent literature 5. In U.S. Patent 5,093,380, for example, low frequency cast foams having resonant frequencies of less than 4 Hz are prepared by the reaction of an injection of a di- or polyisocyanate with a polyoxypropylene polyol. coated with relatively high molecular weight polyoxyethylene, i.e. one having a hydroxyl number of 5 to 38, which also has an unsaturation and < 0.9 / (x-10) where x is the hydroxyl number. This ratio corresponds to unsaturations less than 0.9 in a hydroxyl number of 11, to 0.032 in hydroxyl number of 38. Thus, the patent will seem to indicate that when the higher molecular weight polyols are used, greater unsaturation can be tolerated. Unsaturations are exemplified in the range of 0.Q20 to 0.026. Consistent with Kinkelaar et al., The ball rebound values of these foams are high, minimally about 70 and averaging 80, to achieve resonant frequencies below 4 Hz. The foams of a similar injection (TDI HR) prepared of higher unsaturation polyols show a resonant frequency slightly higher (4.0 to 4.3 J_z) and somewhat lower elasticity, but produce a low quality foam. U.S. Patent 5,300,535 is similar in some respects to U.S. Patent no. 5,093,380, where it is shown that the high ball bounce is necessary to obtain excellent vibrational attenuation properties. However, U.S. Patent 5,300,535 describes an associated problem with the use of low unsaturation polyols due to its higher viscosity than normal. Due to the higher viscosity, mixing of the polyol component with the isocyanate component is difficult. U.S. Patent 5,300,535 solves this problem by diluting the polyol with a polymerizable unsaturation monomer such as a (meth) acrylate. However, the use of these monomers is not desired in industrial environments. As in U.S. Patent 5,093,380, frequency foams are disclosed resonant very low and high ball bounce. In U.S. Patent 5,674,920, numerous problems are addressed in association with the low resonant frequency foams. According to patents 920, high elasticity groups are required and of low compression. The solution to this problem is __c «_¿_fc _____ * _« _ it_. "-._ ^ .. ^^ _ YES ___" .... .__ »_.___...., ..-., > . *. *. . *** ._-___ í t ^ s? ^^^ Jt ^ loqró through the use of polyphenylenepolymethylene polyisocyanates having a mostly specific ring content, together with polyols having a monol content of less than 15 per one hundred mole and one portion of oxypropylene for head-to-tail selectivity of more than 96 mole percent. Unfortunately, isocyanate mixtures must be made or mixed separately, and highly specific polyols can only be produced by catalyzed oxyalkylation at low temperatures. Due to the low temperature, the production of these polyols requires a considerable higher cost. The '920 patent discloses a conventional prepolymer technique where the resin side is a mixture of conventional polymer and polyether polyols with only a minor amount of water on the B side as a foaming agent. The foams prepared from both claimed compositions as well as the comparative compositions had high elasticity, on average. It will be desirable to provide molded polyurethane foams that display low resonant frequencies and exhibit superior vibration characteristics than the technologies of TDI HR, hot-cured TDI, and MDl HR currently used for automotive seat foam. It will also be desirable to produce foams of low resonant frequency and high attenuation while avoiding the use of unsaturated diluents, and without requiring isocyanate and polyol compositions that are not readily available or whose preparation does not have an effective cost.

BRIEF DESCRIPTION OF THE INVENTION It has surprisingly been found that seat foams having qualities can be prepared. of excellent absorbency / vibration attenuation can be prepared from low isocyanate prepolymers of low intrinsic unsaturation and a curing flow comprising water in the bulk of mol, and optionally an amine, an isocyanate index, μna foam density, and other parameters of attenuation and vibration affectation that are maintained so that the elasticity of the foam, measured by ball bounce, is less than 70%, and the resonant frequency is less than about 7 Hz as measured by the method of test described in this. The resulting foams not only show a low resonant frequency, but also a superior vibration control as compared to the foams of an injection.

Brief Description of the Drawings Figure 1 is a schematic of the test method used to measure the resonant frequency of polyurethane foams. Figure 2 is a planning of the transmissivity (A / As) of a polyurethane foam.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The polyurethane foams of the present invention are flexible molded seat foams of low-resonance, low-rebound ball polyurethane. The object foams are suitable for dynamic applications for seats where the attenuation of transmitted vibrational energy is desired. By "low resonant frequency" is meant a resonant frequency below approximately 7 Hz, preferably in the range of 2-6 Hz. By "low ball rebound" it is meant that the ball rebound, as measured by ASTM D3574, is less than about 70%. The ball bounce is preferably less than 65%, and more preferably in the range of 50-60%. The molded polyurethane foams of the present invention are prepared by the water / amine chain extension of one or more terminated isocyanate prepolymers of low intrinsic unsaturation. ._-____ ^^ "_ * r__ .7 | B || g¡a ^ By the term" low intrinsic unsaturation "with respect to the finished isocyanate prepolymers means that the prepolymers are prepared by reacting a stoichiometric excess of di- or polyisocyanate with a polyol of low intrinsic unsaturation. By "low intrinsic unsaturation polyol" is meant a polyoxyalkylene polyol or mixture thereof, preferably a polyol containing the predominantly oxypropylene portion, which has an unavoidable or "intrinsic" unsaturation average of less than 0 025 meq / g. The intrinsic unsaturation is preferably less than 0.020 meq / g, more preferably less than 0.015 meq / g, and more preferably below 0.010 meq / g, ie in the range of 0.002 to 0.008 meq / g. The "intrinsic" unsaturation will be distinguished from the "induced" instauration, i.e. the unsaturation which is added to a particular polyol during or following its preparation to provide sites of reactive unsaturation necessary for the preparation of polymer polyols. The preparation of polyols with low intrinsic unsaturation is within the skill level in the art. The preparation is preferably affected using double metal cyanide catalysts such as those described in .. ^^^ ¿^ > . - ^ -, r, ^ M p? t? toJ * ..,. ^ ** ^.

U.S. Patent Nos. 5,470,813; 5,482,908; 5,712,216; 5,627,122; and 5,545,601. The polyol component used to prepare the low intrinsic unsaturation prepolymers of the subject invention may contain one or more polyols and may, in addition, contain chain diluents, ie isocyanate reactive low molecular weight compounds and oligomers., preferably aliphatic glycols and polyoxyalkylated glycol oligomers having molecular weights below about 1000 Da. However, the major portion of the polyol component, by weight, should consist of polyoxyalkylene polyols having equivalent weights in excess of 1000 Da, preferably in the range of 1500 Da to 5000 Da, and more preferably in the range of 1800 Da to 3000 Da. It is important that the average unsaturation of the polyol component, as measured by ASTM D2849-69, "Testing Of Urethane Foam Poly Raw Material Metais" is 0.025 meq / g or less, more preferably 0.020 meq / g or less, and preferably about 0.015 meq / g or less. Instead of measuring the actual unsaturation d, the polyol component, the unsaturation can be calculated from the measured unsaturations of the component polyols. In these calculations, polyols and chain diluents having equivalent weights of less than 500 Da may be omitted. Most of the polyols in the polyol component having equivalent weights in excess of 1000 Da should consist of polyols of low intrinsic unsaturation, preferably polyols having the unsaturation of less than 0.015 meq / g, and more preferably less than 0.010 meq / g. g. As previously indicated, the overall intrinsic unsaturation of the polyol component should not exceed 0.025 meq / g, and preferably lower. More preferably, the employed polyols having equivalent weights greater than 1000 Da are prepared by complex catalyzed oxyalkylation of double metal cyanide. Preferred polyols have head to tail selectivities of less than 96%, advantageously less than 90%. By the term "portion containing predominantly oxypropylene" and similar terms is meant that greater than 50 percent by weight of the portion of the polyol component consisting of polyols with equivalent weights greater than 1000 Da, are oxypropylene portions. Preferably, each polyol present in a substantial amount in the polyol component, must contain more than about 50 percent by weight portions of oxypropylene, more ^ g ^^^^ preferably greater than 65 percent by weight. Preferably, the oxyalkylene portions in place of the oxypropylene portions are oxyethylene portions, present internally in block, randomly, or randomly in block, or externally as a homopoly-oxyethylene block or a copolymer block. Other oxyalkylene portions such as 1-oxypropylene (oxetane derivative), oxybutylene (1,2-butylene oxide derivative and / or 2,3-butylene oxide) and other portions of oxyalkylene are also suitable as those derived from styrene oxide and halogenated alkylene oxides. Preferably, all the oxyalkylene portions are propylene oxide or ethylene oxide. More preferably, when the polyols of Low intrinsic unsaturation are prepared by catalyzed oxyalkylation of double metal cyanide, any substantial polyoxypropylene block will minimally contain about 1.5 percent by weight of random oxyethylene portions. Suitable isocyanate components in the preparation of the finished isocyanate prepolymers of the subject invention include the known aromatic and aliphatic di- and polyisocyanates, for example 2,4- and 2,6-toluene diisocyanates and mixtures thereof.

(TDIs), 2,2'-, 2,4'- and 4,4'-diisocyanates methylene diphenylene and mixtures thereof (MDIs). polyphenylene polymethylene polyisocyanates (PMDIs), 1,6-hexanediisocyanate, isophorone diisocyanate, and mixtures of these isocyanates. Other 5 isocyanates can also be used. Also suitable are so-called modified isocyanates prepared by reacting a di- or polyisocyanate with an isocyanate reagent monomer or oligomer or with it. Examples are modified urethane isocyanates prepared by Reacting a di- or polyisocyanate or mixture thereof with one or more glycols, triols, oligomeric polyoxyalkylene diols or polyols or mixtures thereof; the modified urea isocyanates prepared by reacting the isocyanate with a polyoxyalkylene diamine or amino-terminated polyether oligomer; and carbodiimide, polyisocyanurate, uretonimine, allophanate and modified uretdione polyisocyanates prepared by reacting the isocyanate or the modified isocyanate in the presence of a convenient catalyst. These isocyanates and the modified isocyanates are well established as commercial articles. Particularly, preferred di- and / or polyisocyanates include TDIs, MDIs, PMDIs and mixtures thereof, particularly mixtures of __ft__tt ______ ^, *. * # Mte? > r < - ^ -, _r .. ^ C_. ^ i ^ BA ^^ TDIs and MDIs, the latter preferably containing a substantial majority of the 4,4'-isomer. The prepolymers of the subject invention are prepared in the conventional manner by reacting the polyol component with the isocyanate component with or without the urethane that promotes the catalysts, as described, for example, in POLYURETHANE HANDBOOK, Gunter Oertel, Hanser Publishers , Munich® 1985, and POLYURETHANES: CHEMISTRY AND TECHNOLOGY, JH Saunders and K.C. Frisch, Interscience Publishers, New York, 1963, and in U.S. Patent No. 5,070,114, incorporated herein by reference. The continuous and batch process for the preparation of finished isocyanate prepolymers is described in "Continuous Precessing of Urethane Foam Prepolymers", J.R. Wall, CHEMICAL ENGR. PROGRESS, V. 57, No. 10, pp. 48-51; Sanders, op.cit., Part II, pp. 38-43; U.S. Patent No. 5,278,274; published European application EP 0 480 588 A2; and Canadian Patent No. 2,088,521. The prepolymers of the subject invention have a free isocyanate (NCO) group content of 5 percent by weight to 35 percent by weight, preferably 6 percent by weight to 25 percent by weight, and advantageously 8 percent by weight. 20 percent by weight. The finished isocyanate prepolymers comprise the A side (iso side) of the molded polyurethane foam system. Side B (resin side) or, the molded polyurethane foam system of the subject invention employs the isocyanate reactive components, foam-forming agent (s), surfactant (s), and other additives and auxiliaries, example chain diluents, crosslinkers, catalysts, dyes, pigments, fillers, etc. Additives that are not reactive with the isocyanates can be added to the A side of the formulation. The catalysts are generally necessary.

The catalysts can be selected from conventional urethane promoting catalysts, for example, tin catalysts such as dibutyltin diacetate, dibutyltin dilaurate, stannous octoate, and the like; amine catalysts as NIAX®A-1, diethylene triamine, 1,4-diazabicyclo [2.2.2] octane, and the like. Mixtures of metal catalysts and amine catalysts can also be used. Amine catalysts are preferred. The amounts of catalysts can to be easily determined by one skilled in the art, and ugjiÍ g "^^^^^^ to ^ g |? ^^^^ for example, can range from 0.1 to 5 percent by weight based on the weight of the foam. Suitable chain diluents include various oligomeric alkylene glycols and polyoxyalkylene glycols with molecular weights of up to about 300 Da, for example, ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, tripropylene glycol, and the like. The amount of chain diluent can be adjusted to provide the necessary process or physical parameters of the foam. Preferably, only most minor amounts of chain extenders is used for, for example less than 10% by weight and preferably less than 5% p so in relation to the weight of the foam. Functional amino chain diluents such as aliphatic diamines, MOCA, toluene diamine, and obtuse aromatic amines may also be convenient. Suitable crosslinkers include the functional monomeric polyhydroxyl compounds such as glycerin, but preferably the alkanolamipas such as monoethanolamine, diethylamine (DEOA) and triethanolamine (TEOA). As with chain diluents, crosslinkers, when used, are preferably used in most " _"_"___"___"to_- ,____. _., ..__ ^^^^^^^^^^^^^^^^ .- ^ M ^^ ^^ minor amounts, for example less than 10 weight percent and more preferably less than 5 percent by weight in relation to the total weight of the foam. Chain diluents and crosslinkers, when used, are preferably dissolved in water which serves as the foaming agent. Generally, a cell stabilizing surfactant is required. Surfactants suitable cell stabilization include various organopolysiloxanes and organopolysiloxanes 10 polyoxyalkylene and known to those skilled in the art well. Suitable surfactants include DC5043 available from Air Products, and Y-10,515 available from Witco. Additional surfactants are available from Wacker Silicones, Adrián, MI, and Goldschmidt A.G., Germany. Combinations of surfactants can also be used, for example, a mixture of Tergitol 15-S-9 available from Union Carbide Corporation and DC5043. The amount of surfactant should be an effective amount to avoid collapse of the foam, and readily determined by one skilled in the art. The amounts of 0.1 to about 5 percent by weight, preferably 0.5 to 2 percent by weight based on the weight of the foam, may be convenient. _____ t _._- «.____... J._ ___ i _? __________________ ^ r * > * at * Jt¿z ^ -.

The B-side may further contain polyoxyalkylene polyols and / or polyols modified polyoxyalkylene polymer wherein the polyols have molecular weights of c.a. of 300 Da or greater, preferably the equivalent weights of 500 to 5000, more preferably 1000 to 3000. The B side may contain up to 30 percent by weight of these polyols, but preferably not more than 20%, more preferably less than 10. %. More preferably, the prepolymer contains more than 90% total polyol, and in particular virtually all of the polyol. For the same reason, the high primary hydroxyl content is not necessary for any B-side polyol. However, the B-side polyols may advantageously contain more than 50 mole percent, and more preferably greater than 70 mole percent. of primary hydroxyl groups. Preferably, no additional polyoxyalkylene polyol is contained in the B side formulation. The B side contains water or other foam forming agent of the chemical type. The preferred foaming agent is water, which reacts with the isocyanate to generate urea bonds with concomitant release of carbon dioxide gas. Physical foam-forming agents can also be used in conjunction with water. Non-limiting examples of additional foaming agents include lower alkanes, for example, butane, isobutane, pentane, cyclopentane, hexane, and the like; the 5 chlorofluorocarbons (CFCs), for example, chlorotrifluoromethane, dichlorodifluoromethane, and the like; hydrochlorofluorocarbons (HCFCs) such as fluorodichloromethane and chlorodifluoromethane; aliphatic and cycloaliphatic hydrocarbons of 3 to 8 carbon atoms perfluorinated (PFCs) and substantially fluorinated analogues (HPFCs); chlorinated hydrocarbons such as methylendichloride, liquid C02, and the like. CFCs are preferably avoided due to environmental concerns. As previously stated, the preferred foaming agent is water, which is more preferably used only as the foaming agent. Foaming agents such as C02, nitrogen, and air can also be introduced. The amount of foaming agent is selected to provide a foam density of about 0.45 kg / m3 (1.0 lb / ft3) or less than 1.82 kg / m3 (4.0 lb / ft3) or more, more preferably 0.45 kg / m3 (1.0 lb / ft3) to 3.0 lb / ft3, and preferably from approximately 0.54 kg / m3 (1.2 lb / ft3) to approximately 25 1.27 kg / m3 (2.8 lb / ft3). The amounts of water go from ^^^^^^^^^^^^ & ?? ^^ mi ^^^^^ M ^^^ A Haa_______B_____ 1.0 part to 5.0 parts per 100 parts of foam formulation ingredients, preferably 2.0 parts to approximately 4.5 parts mainly. Side A and side B are combined conventionally using low pressure or main high pressure mixture and introduced into the mold which is optionally and preferably maintained at about room temperature. Mold temperature can be maintained at a convenient temperature to heat or cool the molding. The mold can be closed, with the ingredients forming the foam introduced into an appropriate loading port, or a mold that is closed following the introduction of the foam formulation can be opened. The term "closed mold" includes both types as well as any variant. The cells are opened in the molded foam before demolding by delayed pressure release (TPR) as described in the North American Cavender patents 4,579,700 and 4,717,518, and / or grinding after demolding, followed by curing in a conventional manner. It has surprisingly been found that not only are the foam formulations d, the process of the subject invention, but also, the foams are of superior quality as compared conventional foams from similar systems that do not * ttfc * »*» - ^ »* _ > . _______..____ < ___ fc __ * __ ^ _-__ t __. _ *. . , Use polyols of low intrinsic unsaturation. In addition, these results are normally achieved from polyols independent of the primary hydroxyl content normally required to produce the molded foam. In a preferred embodiment of the process of the subject invention, a configuration of 4 flows is used in the main mixture. A flow comprising the activating flow, and preferably constitutes a portion largest of water, optionally contains sufactant (s), catalyst (s), amines, alkanolamines, and traditional polyurethane additives. A second flow comprises an isocyanate stream, and may contain one or more conventional modified or unmodified isocyanates.

A third flow constitutes an isocyanate prepolymer stream terminated low in solids (or nq), generally prepared, as previously indicated, by reaction of a polyol of low intrinsic unsaturation with excess isocyanate, with or without low polyol of Polymer contained in the polyol component; and a fourth stream comprises a "high" prepolymer in solids, prepared previously as indicated, but with appreciable polymer polyol solids. By the use of this process of four flows, a wide variety of foams can be prepared. In __ * ___ to ___- ^ ___- * _._ .. ^ ._____ t ____ ^ ._____________... ^ _ ^ 1t ^^^ -,., | Hg¡ particular, the establishment of charge through the addition of isocyanate can practiced effectively. The preferred compositional ranges of each flow are listed in the following table. All quantities are partly by weight in relation to the total weight of each individual flow.

TABLE 1 fifteen Changing only the proportion of the various flows, a wide variety of foams can be produced, including a coarse series of molded foam useful for automotive seats, particularly foams with a density in the range of 20-70 kg / m3, and firmness in the range of 1-14 kPa (50% of CFD). 25 ^ gto ^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ isocyanate functional groups for a main mix and two water flows, the last catalysts contain, crosslinkers, etc., with an optimized water flow for low density foam applications and the other optimized water flow for density applications high. Functional isocyanate streams include one having a high polymer content, i.e. comprising one or more terminated isocyanate prepolymers, while the second functional isocyanate stream has a low polymer content, i.e., is a prepolymer containing high NCO, a quasi-polymer, or a prepolymer containing high or low NCO in the mixture with di- or unreacted polyisocyanate. The first functional isocyanate stream also generally contains a substantial amount of polymer polyol, while the second functional isocyanate stream contains little or no polymer polyol. By the use In the case of the flows of the functional isocyanate "prepolymer", the solids and isocyanate content can simply be adjusted by changing the ratio of these flows to each other. For example, a highly relative proportion of the low solids flow (high in isocyanate) relative to the high solids flow could be used together with a optimized water catalyst flow for high density applications to prepare the automotive molded seat cushions, while a higher relative ratio of high solids flux 5 (low in isocyanate) could be used with a second water / catalyst flow to prepare the Low density seat backrests. In the past, the change from a higher density, from higher hardness foam to a lower density, from soft foam has required changes in the prices of the flows supplied to the main mix. In the process of the subject invention, changes in production can be accommodated simply by changing the proportion of high isocyanate streams in solids / few or no solids, optionally together with select a different optimized water / catalyst flow or changing the ratio of the water / catalyst flows. Thus, the subject invention also provides a process for the flexible production of various types of molded polyurethane foams of a simple masterbatch without changing the supply of the reactant component of the main mixture, providing at least a first activating flow comprising, a greater molar proportion of water and the catalyst than promotes polyurethane; and optionally a first flow alternative activator comprising a higher molar proportion of water and the catalyst that promotes the polyurethane, the first activating flow is different from the first secondary activating flow; and at least two and optionally three functional isocyanate streams: I a second, isocyanate stream comprising one or more di- or polyisocyanates; a third, low solids prepolymer flow having a low solids content of dispersed phase polymer, preferably in the range from 0 percent by weight to about 10 percent by weight; and a fourth, high solids prepolymer flow having a high content of dispersed phase polymer solids, for example in the range of 15 percent by weight to 60 per cent per cell. weight; selecting as molding flows at least one of the third and fourth flows, and optionally also selecting the second flow to supply the isocyanate reactive components for a mold; and selecting at least one of the first activating flow and the first alternative activating flow; mix the I molding flows; and introduce the molding flows in a mold. Generally, this invention having been described, a further understanding can be obtained by reference to certain specific examples that 'f9B. ~ are provided herein for purposes of illustration and are not intended to be limited unless otherwise specified. In the Examples that follow, polyol A is a catalyzed polyoxypropylene triol (base) conventionally having a hydroxyl number of 31, a c.a. of unsaturation of 0:05 meq / g, and 16 percent by weight of polyoxyethylene cover; Polyol B is an intrinsic low unsaturation triol having a hydroxyl number of 28, an unsaturation of only 0.005 meq / g, and contains random internal oxyethylene portions of 20 percent by weight, of which 15 percent by weight. Weight are present as a random external block having a weight ratio of oxyethylene to oxypropylene of 45:55. The polyol C is a polymer polyol prepared by the polymerization in itself of 35:65 acrylonitrile and styrene at 40 percent by weight solids, in a hydroxyl number of 35 conventionally of catalyzed triol having an unsaturation of 0.035 meq. / g and a polyoxyethylene coating of 19 percent by weight; and the polyol D is a polymer polyol similar to polyol C wherein the base polyol is an intrinsic low unsaturation triol having a hydroxyl number 28, an unsaturation of 0.004 meq / g and containing oxyethylene portions ___ faith -__-___ random internal 20 percent by weight distributed in the same manner as in Polyol B. The vibration data presented herein was determined using a laboratory scale test as illustrated in Figure 1 and a example of the data of this equipment is shown in Figure 2. In this test the foam sample was placed in a servo-hydraulic powered base plate 1 (MTS Corp., Minneapolis, MN) and a mass 3 set freely in the foam 5. The mass was 22.7 kg and was of the same diameter as a standard IFD indentor foot (200 m?). The acceleration data were measured by means of the accelerometers 7 (Piezoelectronic PCB) energized by supplying power 9 and the data acquired by the data acquisition module 11, and analyzed and recorded in real time in the computer 13. The activator Servohydraulic was programmed to perform a frequency curve from 1 to 16 Hz in 150 seconds. During the curve, the amplitude decreases as the frequency increases to maintain a constant peak input acceleration (AD in Figure 2) of 0.2 g. Transmissivity is reported as the response (A) divided by the input (A0) of the peak acceleration, ie a __ ^ te __- «Transmissivity = A / Ac.

A normal plane is shown in Figure 2. This test method does not provide the natural frequency in use of an identical foam mounted vehicle seat, however, this test method is a powerful tool to compare under laboratory conditions, the vibration responses of several foams. Thus, this test is an indication of how the foams are compared in use with each other. Except where indicated otherwise, physical properties are measured by methods consistent with those generally employed in the industry. Measures in accordance with ASTM D-357481"Standard Test Metods for Cellular Materials - Slab, Bonded, and Molded Urethane Foams ", are as follows: density (Test A); the ball bouncing (Test H); air flow (Test G); tensile strength and prolongation (Test E); Tear resistance (Test F); 50% and 75% dry (Test D - Constant Deviation Compression Test); 75% humidity for maturation put to compression, "HACS", (Test J - Maturation of Steam Autoclave). The measurement of resonant frequency of foam and transmissivity A / AD has been previously described. The properties of 25% of JIS IFD, 50% of ^? ni? ti? ~ rm- ^ i * s'? "'' i ^ ÉMBUÍ ti USti ^^^^^^" "^^^^ 3fi '' | ^ Indicated Humidity, and Hysteresis are measured by the appropriate tests and are for comparison purposes only, however, these tests are similar to the tests published in the literature and the results are believed to be comparable to those obtained in the published test methods: 25% of the JIS IFD test is similar to the one described in the Japanese Industrial Standard test.The comparisons were made between the foam conventional injection-molded TDI-based molding, as shown by U.S. Patent 5,093,380, and the prepolymer foams of the present invention. In Examples 1-3, the polyols (polyol A and polymer polyol D) are first reacted with the Isocyanate to form a finished isocyanate prepolymer. The formulations and physical properties of the foams are presented in Table 2 below.

TABLE 2 20 The Examples indicate that the prepolymer technique of the present invention is capable of lowering the ball bounce of molded foam considerably as compared to TDI based foams employing conventional polyols with higher unsaturation. The low ball bounce obtained is considerably lower than that described in US Pat. No. 5,093,380, which uses low unsaturation polyols in conventional injection formulations.

Examples 4-6 Molded foams derived from prepolymer according to the present invention were prepared from finished isocyanate prepolymers derived from the reaction of Polyol E, an initiated glycerin, the polyol of intrinsic low unsaturation of hydroxyl number 24 containing 20% of oxyethylene portions distributed in the same way as Polyols B and D, with a 80/20 weight / weight mixture of TDI / MDI. The compositions and physical properties of the foam are given in Table 3 below.

TABLE 3 fifteen twenty Mj ^^ É ^ SÁÁ ^^? ^^^^^^^^^^^^^^^^^^^^^^^^ .

TABLE 3 CONTINUATION fifteen As can be seen from Table 3, the use of low isocyanate prepolymers of low intrinsic unsaturation with a water activating flow was able to prepare molded foams having very low resonant frequencies as well as low ball bounce. The foams also showed excellent properties of 50% indicated humidity. 25 _ * ____? __ & ________ ^ __-_-_-_ ^. ^^^. ^ _....._ ^, ^ _4__ £ ___ ~ ^ M ___ ^ __ __ ___ faith_ For the term "base seat of foam without spring suspension "and similar terms it is understood that the primary support and absorption of vibration attributed to a vehicle seat are due to the molded foam itself, without support along the bottom of the foam cushion or in its interior by springs of a metallic or composite nature. The use of the spring suspension is the traditional option for vehicular seat applications. The foam cushions of the present invention may be of the same support through the use of molded inserts or may rest on a hard metal, plastic, or equivalent seating substrate. By the term "physicochemical properties" is meant the combination of chemical properties such as polyol, isocyanate, hard segment content, urea group content, and the like, and physical properties such as density, tensile strength, elongation, indicated humidity , etc. By the term "polyurethane catalyst" and the like is meant a catalyst that promotes the formation of polyurethane foam of the reactive mixtures. Catalysts include, but are not limited to, catalysts that promote the reaction of the hydroxyl and isocyanate groups to prepare the linkages of _, _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. catalysts that promote the reaction of water csn the isocyanate to generate the amine and carbon dioxide (foam-forming catalysts), and the like. The molecular weights and equivalent weights expressed herein in Daltons (Da) are the average molecular number and equivalent weights unless otherwise indicated. All percent compositions are percent by weight unless otherwise indicated. The term "major" when used means 50% or more by weight, or per mole when modifying the latter; similarly, "minor" means less than 50% on the same basis. Ingredients can be used in the compositions and processes of the subject invention for the exclusion of unspecified ingredients, if desired. The necessary ingredients, for example, are low intrinsic unsaturation prepolymers as defined herein, an "activator" stream of chain diluent / foaming agent, and effective amounts of catalysts that promote the reaction where they are required by the reactivity of sides A and B. For example, the use of unsaturated low molecular weight viscosity reducers is not preferred, and these can be excluded. The term "resonant frequency" refers to the resonant frequency of the * ff &gs ?? k ^^^^^^^ fa ^ |? 3a ^ ^ ^^^ g «jí ^^^^^^^^ foam as determined by the methodology described herein, or another methodology that produces the equivalent results. Having now fully described the invention, it will be clear to one of ordinary skill in the art that various changes and modifications may be made thereto without departing from the spirit or scope of the invention as indicated herein.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects or products to which it refers. Having described the invention as above, property is claimed as contained in the following: -^ ¿¿¿¿¿¿^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^

Claims (18)

1. A molded polyurethane foam? e has a resonant frequency of 7 Hz or less and a ball bounce of less than 70%, preferably less than 65%, especially less than 60%, such as 50 to 60%, preferably by reaction, in a closed mold, a polyurethane or polyurethane / urea "forming the composition characterized in that it comprises: a) a finished isocyanate prepolymer prepared by the reaction of a stoichiometric excess of one or more di- or polyisocyanates with a polyol component having an average intrinsic unsaturation of less of 0.Q25 meq / g and comprising mostly one or more lower intrinsic low unsaturation polyoxyalkylene polyols of higher functionality having an unsaturation less than 0.025 meq / g and an equivalent weight greater than 1000 Da, with b) a acting flow comprising water and optionally a low molecular weight amine or alkanolamine; .,. ^^ í ^^ i ^ .....- «« _____ * ____., .... ".., .. -íMlmi ~ ß a? ? ~ - | r ^ a_m ^^ __ ^ M _? ^ < iifa, optionally in the presence of c) one or more catalysts that promote the reaction between a) and b).

2. The molded polyurethane foam according to claim 1, characterized in that the polyol component comprises in excess 80% by weight of one or more polyisoxypropylene polyols of low intrinsic unsaturation having a 10 msaturation of 0.015 meq / g. less, preferably 0.010 meq / g or less.

3. The molded polyurethane foam according to claim 1 or 2, characterized 15 because the Acting Flow comprises water and diethanolamine.

4. Molded polyurethane foam according to any previous claim where The polyol component additionally comprises, to a lesser extent, one or more reac isocyanate polyoxyalkylene chain or oligomer oligomers having a molecular weight of less than 1000 Da. 25

5. The molded polyurethane foam according to any preceding claim, characterized in that the polyol component additionally comprises a polymer polyol.

6. The molded polyurethane foam according to claim 5 characterized in that the polymer polyol comprises an intrinsic low unsaturation polymer polyol.

7. The molded polyurethane foam according to any preceding claim, characterized in that at least one or more polyoxyalkylene polyols, of low intrinsic unsaturation, 15 comprises a polyoxypropylene polyol which also contains from 1.5 weight percent to 30 weight percent oxyethylene portions. < -

8. Molded polyurethane foam According to any preceding claim, characterized in that the polyol component comprises one or more low intrinsic msaturation polymer polyols having an intrinsic unsaturation of less than 0.010 meq / g such that the polyol component 25 has an average unsaturation no greater than 0.015 meq / g.

9. The molded polyurethane foam according to any preceding claim, characterized in that the Acting Flow comprises water, an alkanolamine, and optionally a minor amount in percent mole of a glycerol or dipyrimaryl aliphatic polyol.

10. A vehicle seat having a seat cushion characterized in that it comprises in a larger portion a foam in accordance with any preceding claim.

11. The vehicle seat according to claim 10, characterized in that the seat is a base seat of foam devoid of the spring suspension.

12. A process for the preparation of a molded polyurethane foam according to any preceding claim, characterized in that it comprises reacting in a closed mold, a 25 formed polyurethane / urea composition comprising: (a) a finished isocyanate prepolymer prepared by the reaction of a stoichiometric excess of one or more di- or polyisocyanates with a polyol component having an average unsaturation intrinsic of less than 0.025 meq / g and comprises in bulk one or more polyoxyalkylene diols or polyols of substantially low unsaturation 10 intrinsic greater functionality that has an unsaturation less than 0.025 meq / g and an equivalent weight greater than 1000 Da; with 15 b) an activating flow comprising water and optionally a low molecular weight amine or alkanolamine; optionally in the presence of c) one or more catalysts that promote 20 reaction between a) and b).

13. A process according to claim 12, characterized in that the reagents or products are defined in any of the 25 claims 1 to 9.

14. In a process for the production of molded polyurethane foam by the reaction of a finished isocyanate prepolymer with a water flow, the process characterized in that it comprises: supplying to a main mixture, four reactive streams, the four reactive streams comprising: a) a first, Activating Flow comprising a greater molar proportion of water; b) a second, isocyanate flow, comprising one or more di- or organic polyisocyanates; c) a third, low prepolymer flow in solids comprising one or more terminated isocyanate prepolymers, the prepolymers together have a dispersed phase polymer solids content of 0 percent by weight to 10 percent by weight based on weight of the polyols contained in the prepolymer (s) of the low prepolymer flow in solids; d) a quarter, high prepolymer flow in solids comprising one or more finished isocyanate prepolymers, the fourth flow contains 15 percent -______ »^. A __« J _! _ .. ^ ... Jt ^ _, ... J, M, * MM ^ - "*" "" * * * £ & ** by weight at 60 percent by weight of dispersed phase polymer solids based on the weight of polyols contained in the high solids prepolymer stream, introducing a portion of the first, activating flow, and at least two of the second, third, and fourth streams in the Main mix, mix the flows in the main mix to form a mixture of reactive polyurethane foam, introduce the mixture of reactive polyurethane foam into a mold, and recover a polyurethane foam from the mold.

15. The process according to claim 14, characterized in that all the polyols in the low prepolymer flow prepolymers in solids and the high solids prepolymer flow prepolymers having equivalent weights greater than 1000 Da are polyols of low intrinsic unsaturation.

16. The process according to claim 14 or 15, characterized in that the physicochemical properties of the foam are altered by varying the ratio of one or more flows from a) to d) K > __j_ without changing the compositional composition of any single flow.

17. The process according to claim 14, 15 or 16, characterized in that the following reaction of the flows of a) to d) to form a polyurethane / urea foam and curing of the foam, the curing of the foam shows a resonant frequency of less than 7 Hz and a ball bounce of less than 70.

18. A process for the preparation of two or more molded polyurethane foams having physicochemical properties different from a simple main mixture, the process is characterized in that it comprises: 1) supplying to a main mixture a) one or more activating flows a) i) a first activating flow comprising a greater molar proportion of water, and a) ii) a first alternative activating flow different from the first activating flow and comprising a greater molar proportion of water, ^ & ^ ü ^ ¡j¿¡ ^? one or more activating flows that supply the main mixture with at least one polyurethane catalyst; b) two or more functional isocyanate streams 5 b) i) a second, isocyanate stream comprising one or more di- or organic polyisocyanates; b) ii) a third, low solids prepolymer flow comprising 10 one or more terminated isocyanate prepolymers, the prepolymers together have a dispersed phase polymer solids content from 0 percent by weight to about 10 percent by weight based on the weight of the polyols contained in the prepolymer (s) of the low prepolymer flow in solids; b) iii) a fourth, high solids prepolymer flow comprising one or more terminated isocyanate prepolymers, the 25 fourth flow containing 15 lt? í ** J _? nilrfÉMiá-i -ffrrMrrri _ ¿____ ^ _ ._____________.__ _¿ ^ ¡^ H percent per weight at 60 percent by weight solids dispersed phase polymer based on weight of the polyols 5 contained in the flow of prepolymer high in solids; at least one of the two or more reactive isocyanate streams selected from b) ii) or b) iii); 10 2) mixing in the main mixture a portion of an activating flow derived from a) i), a) ii) or both a) i) and a) ii) and one or more reactive isocyanate streams b) i), b) ii), or b) iii, wherein at least one or more isocyanate reactant streams is a stream containing 15 the prepolymer b) ii or b) iii, to form a mixture of reactive polyurethane foam; 3) introducing the reactive polyurethane foam mixture into a mold; and 4) recovering from the mold a first molded polyurethane foam having a first group of physicochemical properties; and 5) alternate the relative proportions of the 25 flows a) i, a) ii), b) i), b) ii), and b) iii) mixed in the main mix in step 2) without altering the flow supply a) i) ab) iii) provided in step 1) and repeating steps 2 to 4 to recover a second molded polyurethane foam having the physicochemical properties different from the first molded polyurethane foam.