MXPA00003071A - A method for forming integral skin flexible foams from high purity cyclopentane and blend thereof - Google Patents

Abstract

A process for the preparation of polyurethane containing molded articles having a compressed peripheral zone and a cellular core is provided. The novel integral skin flexible foams according to the present invention are formed using a very stable/homogeneous high purity cyclopentane or cyclopentane/iso- or n-pentane blend blowing agent component. The molded articles are produced by introducing into a mold a mixture which comprises:(a) an organic and/or modified organic polyisocyanate, (b) at least one higher molecular weight compound having at least two reactive hydrogen atoms, (c) optionally, a lower molecular weight chain extending agent and/or cross-linking agent, (d) a blowing agent comprising high purity cyclopentane, and (e) a catalyst capable of forming a molded article having a compressed peripheral zone and a cellular core, and allowing it to react.

Description

A METHOD FOR FORMING FLEXIBLE FOAMS OF INTEGRAL EPIDERMIS FROM CYCLOPENTAN OF HIGH PURITY AND PHYSICAL MIXTURES OF THE SAME The present invention relates to a process for the preparation of polyurethane containing molded articles with a compressed peripheral zone and a cellular core. The novel flexible integral epidermal foams according to the present invention are formed using a very stable / homogeneous mixture of high purity of cyclopentane or cyclopenta-no / iso or n-pentane with blowing agent component the molded articles, according to to the present invention, they are particularly suitable for the manufacture of shoe soles and products for the recreational vehicle and automobile industry, for example, bumper covers, molded for impact protection, and parts such as scuttle moldings, bumpers, stops and tire extensions, as well as components for engineering housings and rollers. These integral epidermal foams can also be used, for example, in rests for arms, for headrests, for safety covers in automobile interiors and as seats for motorcycles and bicycles and finally as covers for composite foams. Background of the Invention The preparation of molded articles having a cellular core and a compressed peripheral zone has been known for some time and, for example, is described in the following patents: DE-A-1694138, GB-A-1209243, DE-A-955891, GB-A-1321679 and US-A-3824199. Such products are generally prepared by reacting organic polyisocyanates, higher molecular weight compounds having at least two reactive hydrogen atoms and, optionally, chain extension agents in the presence of blowing agents, more preferably physically active blowing agents, auxiliary catalysts and / or additives in a closed mold, optionally heated using compression. Also known is the preparation and use of the urethane group containing shoe soles manufactured by the process of addition and polymerization of polyisocyanate in the footwear industry. The direct application of shoe soles and the manufacture of finished polyurethane soles are the main areas of application for polyurethanes in the footwear industry. Said soles of polyurethane shoes can be manufactured using high or low pressure (RIM) technology (Schuh Technik + abe, 10/1980, pages 822 et seq.). A comprehensive review of integral polyurethane epidermal foams has been published, for example, in "Integral Skin Foams" by H. Piechto and H. Rohr, Carl-Hanser Editors, Munich, 1975, and in Plastics Handbook, volume 7, Polyurethanes, by G. Oertel, Editors Carl-Hanser, Munich, second edition, 1983, pages 333 et seq. The last reference describes (pages 362-366) the use of integral epidermal foams in the footwear industry. Essentially two types of blowing agents are used in the preparation of cellular plastics using the process of addition of polyisocyanate and polymerization: inert liquids with low boiling points which evaporate under the influence of the exothermic reaction of addition and polymerization; for example, alkanes, butane, pentane, etc., or preferably halogenated hydrocarbons, such as methylene chloride, dichloro-monofluoromethane, trichlorofluoromethane, etc .; and chemical compounds that form propellants through a chemical reaction or by thermal decomposition. Examples of the latter are the reaction of water with isocyanates to form amines and carbon dioxide, which occurs in synchronization with the formation of the polyurethane, and in the partition of thermally unstable compounds, such as, for example, nitrile azoisobutyric acid. co, which, together with the nitrogen as a partition product forms the toxic dinitrile tetramethyl-succinic acid or the azodicarbonamide whose use as a component in a blowing agent combination is described in EP-A-0092740. While the latter method in which thermally unstable compounds such as azo compounds, hydrazides, semi-carbacides, N-nitrose compounds, benzooxazines, etc., are generally - A - incorporated into the prefabricated polymer, or laminated into plastic granules after which, the compound is formed into foam by extrusion, said method has remained as Of low industrial importance, the physically active and low-boiling liquid, particularly chlorofluoroalkanes (CFCs), are used worldwide on a large scale to produce polyurethane foams and polyisocyanurate foams. A disadvantage of propellants is the problem of environmental pollution. When the propellants are formed by thermal partition, or by chemical reaction, partition products and / or reactive by-products are formed and incorporated into the addition-polymerization product or chemically bound and this can lead to an undesirable change in the mechanical properties of plastic. In the case of formation of carbon dioxide from water and diisocyanate, urea groups are formed in the addition-polymerization product, and, depending on their amount, can lead to both an improvement in compressive strength and the fragility of polyurethane. Although aliphatic hydrocarbons such as pentane, hexane and heptane are cheap and not hazardous to health, in the prior art they are only used for thermoplastic foams. Pentane and its isomers, for example, are used in the preparation of expanded polystyrene (Kunststoffe 62 (1972), pages 206-208), as well as in phenolic resin foams (Kunststoffe 60 (1970), pages 548-549). DE-A-1155234 (GB-A-904003) describes the preparation of polyurethane foams from an isocyanate group containing prepolymer while using a blowing agent mixture comprising water and a soluble inert gas which is low liquid Pressure. Cited as typical inert gases are, for example, gaseous hydrocarbons, halogenated hydrocarbons, ethylene oxide, nitric oxides, sulfur dioxide and more preferably carbon dioxide. According to GB-A-876977, saturated and unsaturated hydrocarbons, saturated or unsaturated dialkyl ethers and fluorine containing halogenated hydrocarbons can be used, for example, as blowing agents in the preparation of rigid polyurethane foams. The high flammability, and according to the expensive safety measures required to use gaseous alkanes in the production, are reasons why the alkanes have not been used in the prior art as blowing agents to form foam of addition polymerization products of polyisocyanate. So far there has been no theoretical agreement on the use of alkanes for the preparation of integral epidermal foams. CA-A-2000019 (Volkert) discloses an insufflation agent that replaced conventional chlorofluoroalkanes as blowing agents in the preparation of integral polyurethane epidermal foams. This blowing agent comprises aliphatic or cycloaliphatic hydrocarbons. Preferred low-boiling cycloalkanes have from 4 to 8 carbon atoms, more preferably from 5 to 6 carbon atoms in the molecule. Most preferred are linear or branched alkanes having from 4 to 8 carbon atoms, more preferably from 5 to 7 carbon atoms in the molecule. Some cycloaliphatic hydrocarbons are, for example, cyclobutane, cyclopentane, cycloheptane, cyclooctane and most preferably cyclohexane. Most preferred are aliphatic hydrocarbons such as, for example, butane, n- and iso-pentane, n- and iso-heptane and n- and iso-octane. Most preferred is iso-pentane, more particularly n-pentane and mixtures of pentanes. However, the problems associated with using conventional alkanes and cycloalkanes as blowing agents are: (1) they are not very soluble in polyols which reduces the shelf life due to instability; and (2) the low purity cyclopentane is also not soluble in polyols. The present inventors have discovered that the use of a novel high purity cyclopentane allows solubility to be obtained with said blowing agents and polyols, such that the useful life increases substantially against the cyclopentanes of low purity. Mixtures with n- or iso-pentane also allow formulators to adjust the size of the core cell to increase or decrease the smoothness of the core. SUMMARY OF THE INVENTION The present invention relates to a method for forming a molded article having a compressed peripheral zone and a cellular core. The process comprises contacting a polyfunctional isocyanate, an isocyanate-reactive compound having at least two active hydrogens, an insufflation agent including high purity cyclopentane and a catalyst, in which the contact is carried out at a temperature, pressure and time sufficient to produce an article having a compressed peripheral zone and a cell nucleus. The isocyanate-reactive compound is selected from a group consisting of high molecular weight compounds, low molecular weight compounds and mixtures thereof, wherein the low molecular weight compound is selected from a group consisting of a chain extender. , a crosslinking agent and a mixture thereof. The present invention also includes a method for forming molded articles which are flexible foams of integral epidermis or cellular elastomers. The method comprises: (1) introducing into a mold a molding mixture comprising: (a) an organic and / or modified organic polyisocyanate, (b) at least one higher molecular weight compound having at least two reactive hydrogen atoms , (c) optionally, a lower molecular weight chain extender agent and / or a crosslinking agent, (d) an insufflation agent comprising high purity cyclopentane, and (e) a catalyst capable of forming a molded article having a compressed peripheral zone and a cellular core, and (2) allowing the molded mixture to react at a temperature, pressure and time sufficient to produce the molded article having a compressed peripheral zone and a cellular core. The present invention also includes molded articles having flexible foams of integral epidermis and cellular elastomers that are prepared by the processes of the present invention. The high purity cyclopentane product is a viable alternative to HCFClb as a blowing agent in polyurethane foam. However, impurities, especially hexanes, decrease the effectiveness of cyclopentane as blowing agent. The present inventors have discovered that n-pentane and hexanes at certain concentrations affect the solubility of cyclopentane in polyols (ie, polyethers and polyesters). Any decrease in the solubility of the blowing agent in the polyols is undesirable because a lower solubility causes a shorter useful life of the resulting foam. The only high purity cyclopentane blowing agent according to the present invention is formed by the process comprising: (I) the dilution of cyclopentadiene with an aliphatic hydrocarbon to produce a cyclopentadiene-rich stream, comprising 15 to 50% by weight of cyclopen-tadiene, (II) hydrogenate the cyclopentadiene-rich stream in the presence of hydrogen and a palladium on alumina catalyst in a first hydrogenation step to convert a large portion of the cyclopentadiene to cyclopentane, then (III) hydrogenate the stream cyclopentadiene rich formed in step (II) in the presence of a massive nickel catalyst in a second hydrogenation step to form crude cyclopentane, (IV) separate the hydrogen from the crude cyclopentane, and (V) instantaneous separation of the crude cyclopentane to form a high purity cyclopentane. The process can then comprise the steps of (VI) recycling the hydrogen obtained from step (IV) in step (I) and / or step (III); (VII) disintegrating the dicyclopentadiene in cyclopentadiene; and (VIII) separating the cyclopentadiene from higher boiling liquids to produce a cyclopentadiene-rich stream for use in step (I). The present invention also includes high purity cyclopentadiene prepared by the process of the present invention which is substantially free of hydrocarbon impurities with 6 to 9 carbon atoms. The reaction is preferably carried out in a closed mold and optionally heated under compression. The process is particularly suitable for the preparation of elastic and flexible shoe soles, which have a total density between 0.4 and 1.0 g / cm, although the initial components are effectively reacted using a single shot process with the help of technology high pressure (RIM). Some other objects, advantages and features of the present invention will be understood by referring to the following specifications in conjunction with the accompanying drawings, in which equal numbers have been assigned equal numbers. Brief Description of the Drawings Figure 1 is a schematic diagram of the cyclopentane processes according to the present invention Description of the Preferred Modality Unexpectedly, high purity cyclopentanes or mixtures of high purity cyclopentanes with non-iso-pentanes were found used as blowing agents provide integral polyurethane epidermis foams with a long service life and adjustable softness that are comparable or even better than the products prepared when using trichlorofluoromethane. The blowing agent may preferably comprise 100% high purity cyclopentane or mixtures with n- or isopentane. The high purity cyclopentane comprises pure cyclopentane in an amount of at least 50 mol%. When used in a mixture with n- or iso-pentanes, it is preferable to have a high purity cyclopentane mixture with either n- or isopentane. Preferably, the high purity cyclopentane comprises (a) cyclopentane and (b) n-pentane and / or iso-pentane in a molar ratio of (a) to (b) between about 50:50 to 99: 1. More preferably, the high purity cyclopentane comprises (a) cyclopentane and (b) n-pentane and / or iso-pentane in a molar ratio of (a) to (b) between 50:50 to 80:20. A highly preferred mixture is high purity cyclopentane and iso-pentane in a molar ratio of 70:30. The present invention is directed to a method for forming molded articles having a compressed peripheral zone and a cellular core (i.e., flexible integral epidermal foams). These flexible integral epidermal foams are preferably formed by a process comprising: preparing a mixture including: (a) an organic and / or modified organic polyisocyanate (b) at least one higher molecular weight compound having at least two reactive hydrogen atoms (c) optionally, a lower molecular weight chain extension agent and a crosslinking agent (d) an insufflating agent comprising cyclopentane high purity and (e) a catalyst capable of forming a flexible integral epidermal foam • allowing the mixture to react at a temperature, pressure and for a sufficient time to produce a flexible integral epidermal foam. The molded article may optionally contain auxiliaries and / or additives. The term "high purity cyclopentane", as used in the present invention, refers to cyclopentane having a purity of 50% or more. The blowing agent of the high purity cyclopentane of the present invention will also be substantially free of hydrocarbons of 6 to 8 carbon atoms and particularly, will be substantially free of hexanes, 2,2-dimethylhexane and isomers. The inventors of the present have discovered that the purity of the cyclopentane is critical for the action of the insufflation to be effective. They have also discovered that the nature of the impurities and the relative amounts present are similarly critical. It has been found that the high purity cyclopentane which is suitable for use, can contain at least one linear or branched pentane isomer, however, it should be substantially free of hydrocarbons of 6 to 8 carbons. Particularly, the high purity cyclopentane should be substantially free of 2,2-dimethylhexane and isomers and should also be substantially free of hexanes. Similarly, a cellular elastomer can be prepared by a process comprising: • preparing a mixture that includes: (a) an organic and / or modified organic polyisocyanate (b) at least one compound of a higher molecular weight having at least two reactive hydrogen atoms (c) optionally, a lower molecular weight chain extension agent and a crosslinking agent (d) an insufflating agent comprising cyclopentane of high purity and (e) a catalyst capable of forming a cellular elastomer and allowing the mixture to react at a temperature, pressure and time sufficient to produce a cellular elastomer. The following should be noted with respect to the typical initial components of (a) through (f) for the preparation of molded articles such as shoe soles, more preferably urethane, or urethane and articles molded with cellular elastomer containing uetane or urea group and more preferably integral epidermal foams. The preferred polyfunctional isocyanate is an organic and / or modified organic polyisocyanate. Organic polyisocyanates suitable for use in the present invention include all of the essentially known polyfunctional monomeric and polymeric isocyanates, which include the aliphatic, cycloaliphatic, aliphatic and aromatic polyfunctional isocyanates. Polyfunctional aromatic isocyanates are preferred. Some specific examples include: alkali diisocyanates with from 4 to 12 carbon atoms in the alkali radical, such as 1,2-diisocyanate dodecane, 2-ethyl-1,4-tetramethylene diisocyanate, 2-methyl-1, 5-pentamethylene diisocyanate , 1,4-diisocyanate tetramethylene, and preferably 1,6-hexamethylene diisocyanate, cycloaliphatic diisocyanate such as 1,3- and 1,4-cyclohexane diisocyanate, as well as any mixture of these isomers, l-isocyanate-3, 3 , 5-trimethyl-5-isocyanatomethylcyclohexane (diisocyanate isophorone), 2,4- and 2,6-diisocyanate hexahydrotoluene, as well as the corresponding isomeric mixtures, 4,4 ', 2,2', and 2,4 Diisocyanates dicyclohexylmethane as well as the corresponding isomeric mixtures; and preferably aromatic diisocyanates and polyisocyanates such as 2,4 and 2,6 diisocyanate toluene and the corresponding isomeric mixtures, 4, 4 '-, 2, 2'-, and 2,4' -diisocyanate dicyclohexylmethane, as well as the corresponding isomeric mixtures; and preferably diisocyanates and polyisocyanates such as 2,4"and 2,6 'diisocyanate toluene and the corresponding isomeric mixtures, mixtures of 4,4'- and 2,4', diphenylmethane diisocyanates and polyphenylenepolymethylene polyisocyanates (polymeric MDI), as well as mixtures of polymeric MDI and toluene diisocyanates Also included are dimers, trimers and prepolymers derived from any of the foregoing polyisocyanates Polyisocyanates and organic dipolyisocyanates can be used individually or in the form of mixtures.The so-called multivalent isocyanates are often used. is, products obtained by chemical reaction of diisocyanates and / or organic polyisocyanates Examples of said organic diisocyanates and / or polyisocyanates are defined in Canadian Patent No. 2,000,019 (Volkert), issued April 14, 1990, which is incorporated herein by reference. by reference Another ingredient used in the process of the present invention, is an isocyanate-reactive compound that has at least two active hydrogens. The isocyanate-reactive compound is selected from the group consisting of a high molecular weight compound, a low molecular weight compound and a mixture. The low molecular weight compound is selected from a group consisting of a chain extender, a crosslinking agent and a mixture thereof. The preferred higher molecular weight compounds (b) having at least two reactive hydrogens include those with a functionality of 2 to 8, preferably 2 to 4, and a molecular weight of 400 to 8,000, preferably between 1,200 and 6,300. For example, polyether polyamines and / or preferably polyols selected from the group consisting of polyether polyols, polyester polyols, polythioethers polyols, polyester amides, polyacetals containing hydroxyl groups, aliphatic polycarbonates containing hydroxyl groups, diols, have been tested as acceptable. triols, polyfunctional alcohols, diamine, triamine, polyfunctional amine, polyether polyamine and mixtures of at least two of the aforementioned compounds. Suitable polyester polyols can be produced, for example, from organic dicarboxylic acids having 2 to 12 carbon atoms, preferably aliphatic dicarboxylic acids having from 4 to 6 carbon atoms, and multivalent alcohols, preferably diols with from 2 to 12 carbon atoms. carbon, preferably from 2 to 6 carbon atoms. Examples of dicarboxylic acids include succinic acid, glutaric acid, adipic acid, suberic acid, acelaic acid, sebacic acid, decanedicarboxylic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid and terephthalic acid. The dicarboxylic acids can be used individually or in mixtures. Instead of the free dicarboxylic acids, derivatives of the corresponding dicarboxylic acids can also be used, such as esters of dicarboxylic acids of alcohols with 1 to 4 carbon atoms or the dicarboxylic acid anhydrides. Mixtures of dicarboxylic acids of succinic acid, glutaric acid and adipic acid are preferred in amounts of 20-35: 35-50: 20-32 parts by weight, especially of adipic acid. Examples of divalent and multivalent alcohols, especially diols, include ethanediol, diethylene glycol, 1,2- and 1,3-propanediol, dipropylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10- decanodiol, glycerol and trimethylolpropane. Ethanediol, diethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol or mixtures of at least two of these diols, especially mixtures of 1,4-butanediol, 1,5-pentanediol and 1, are preferred. 6-hexanediol. Other suitable polyols are presented in Canadian Patent No. 2000019, which is incorporated herein by reference. Molded articles having a compressed peripheral zone and a cellular core and preferably urethane or molded articles containing urethane and urea group can be prepared with or without using chain extension agents and / or cross-linking agents. Nevertheless, to modify the mechanical properties, that is, the hardness, it has been shown that it is advantageous to add (c) chain extenders, crosslinking agents or mixtures thereof. Suitable chain extenders and / or crosslinking agents include diols and / or triols with molecular weights of less than 400, preferably between 60 and 300. Examples include aliphatic, cycloaliphatic and / or araliphatic diols with 2 to 14 carbon atoms , preferably between 4 and 10 carbon atoms, such as ethylene glycol, 1,3-propanediol, 1,10-decanediol, 1,2-, 1,3- and 1,4-dihydroxycyclohexane, diethylene glycol, dipropylene glycol and, preferably, 1,4-butanediol, 1,6-hexanediol and bis (2-hydroxyethyl) -hydroquinone; triols such as 1,2,4- and 1,3,5-trihydroxy-cyclohexane, glycerol, trimethylolethane and trimethylolpropane and polyalkylene oxides containing low molecular weight hydroxyl group based on ethylene oxide and / or 1,2-oxide -propylene and the aforementioned diols and / or triols as starter molecules. In addition to the aforementioned diols and / or triols, or in a mixture thereof as chain extenders or crosslinking agents for preparing articles molded into cellular elastomer and integral epidermal foams, more preferably shoe soles according to this invention, it is also possible to use secondary aromatic diamines, primary aromatic diamines, 3,3 di- / or 3,3'-, 5,5'-diaminodiphenylmethane substituted by tetraalkyls. Said amines are presented in Canadian Patent No. 2000019, which is incorporated herein by reference. These chain extenders and / or crosslinking agents (c) can be used individually or as mixtures of the same or different types of compounds. If chain extenders, crosslinking agents or mixtures are used, they are preferably used in amounts of 2 to 60 weight percent with a preference between 8 to 50 weight percent and especially between 10 and 40 weight percent, based on the weight of components (b) and (c). In the preparation of flexible shoe soles, polyester polyols or polyether polyols having a functionality of 2 to 4, more preferably 2 and a molecular weight of 1,200 to 6,000 are preferably used as the higher molecular weight compound (b). and as a chain extender agent or crosslinking agent (c), primary aromatic diamines which in the ortho position relative to each amino group, have at least one alkyl radical having from 1 to 3 carbon atoms in linked form, or mixtures thereof of said diamines substituted by aromatic alkyl, diols and / or triols. The blowing agents (d) which can be used according to this invention include high purity cyclopentane and mixtures thereof with n- and iso-pentane. It has been surprising to discover that the cyclopentane synthesized from the dicyclopentadiene ("DCP") C10H12 is capable of mixing with the polyester polyols, not requiring additional surfactants or emulsifiers to mix well. As one skilled in the art will now appreciate in understanding this discovery, the mixing ability of this unique cyclopentane creates a foamable mixture having a viscosity low enough to be used, while the EXTRCP does not create this advantage. The inventors of the present invention have further discovered that the use of novel high purity cyclopentane blowing agents of the present invention allows the formulators to obtain better solubility with the polyols, which in turn, advantageously increase the shelf life of mix. The high purity cyclopentane has a boiling point of 49 ° C, which is primarily responsible for the production at maximum thicknesses of integral epidermis. This specific boiling point allows a low elevation of the foam and a lower crushing of cells at the interface of the epidermis / mold. In contrast to the above, the high purity iso- or n-pentane, which has lower boiling points individually or as a mixture, produces higher vapor pressures during the blowing of the foam into the mold than the cyclopentane. This increases the compression of the cell and produces thinner epidermis and softer foams. The use of high purity cyclopentane mixed with iso- and / or n-pentane allows formulators to adjust the thickness and firmness of the epidermis simply by varying from cyclopentane to iso-pentane and / or a normal ratio of pentane to obtain foams with properties specific desired. The unique or special synthesized cyclopentane (SYNCP) used in all embodiments of this invention is obtained from Exxon Chemical Americas as "Exxsol® Cyclopentane" imported. In this regard, the cyclopentane used in the embodiments of this invention is created synthetically by the disintegration or depolymerization of DCP in CP. The synthetic cyclopentane used in the examples of this invention has an excess of 95% pure cyclopentane. The single high purity cyclopentane blowing agent according to the present invention is preferably formed by a process that includes the following steps: (a) disintegration of dicyclopentadiene to cyclopentadiene; (b) separating the cyclopentadian-rich stream from higher boiling liquids; (c) diluting the cyclopentadian-rich stream with recycled saturates in such a way that the content of the cyclopentadian is limited to 15 to 50%; (d) effecting a first hydrogenation of the cyclopentadiene-rich stream in the presence of hydrogen and a palladium on alumina catalyst, thereby converting a substantial portion of the cyclopentadian into cyclopentane; (e) effecting a second hydrogenation of the cyclopentane-rich stream from step (d) in the presence of a massive nickel catalyst wherein any carbon residue is saturated to form a crude cyclopentane product; (f) separating the hydrogen from the crude cyclopentane product; (g) recycling the hydrogen from step (f) to step (a); and (h) instantly separating the crude cyclopentane product to form a substantially pure cyclopentane product (approximately 50% cyclopentane). The simplified equation for the synthesized cyclopentane (SYNCP) according to the present invention is shown below in EQUATION 1: EQUATION 1 Disintegration 4H2 / Catalyst C10H12 > 2C5H6 - > 2 C5H10 Examples of suitable processes for the production of synthesized cyclopentane (CYNCP) according to the present invention are described in GB-A-2271575 and GB-A-2273107, and both are incorporated herein by reference. In GB-A-2271575, cyclopentane is used as a diluent, or carrier during the depolymerization step, ie disintegration to reduce coke formation and the formation of higher trimers, tetramers, and polymers that do not readily decompose in a single molecule, as taught in GB-A-1302481, also incorporated herein by reference. In GB-A-2273107, the catalyst powder is made to circulate through the reaction zones in a slurry form, until it is removed by filtration. This process method allows the hydrogenation of a single unsaturated molecule to cyclopentane at temperatures below 175 degrees centigrade. The advantage of this process is underlined in GB-A-1115145 and in GB-A-1264255, which are incorporated herein by reference. As another example of an implementation of EQUATION 1, C5H6 represents the hydrocarbons of five unsaturated carbon atoms, both linear and cyclic. Some pentadiene (C5H8) may be present during the conversion. In said process, the cyclopentadiene is hydrogenated to cyclopentane, and the pentadiene may undergo hydrogenation and cyclization to cyclopentane using a catalyst, that is, a transition metal catalyst (or adducts). An example of a palladium metal adduct is PdCl2. A process for making high purity cyclopentane (ie, 50% or greater) by dividing dicyclopentadiene and completely hydrogenating the single cyclopentadiene molecule in a single unit is illustrated in Figure 1 attached. The general process scheme involves diluting commercially available dicyclopentadiene with an aliphatic hydrocarbon fluid of specific volatility and solvency. This material is then introduced into a distillation apparatus in which the dicyclopentadiene decomposes (or depolymerizes) into a single molecule of cyclopentadiene. A reflux of the distillation apparatus consists of a recycle stream of the cyclopentane product. This reflux aids distillation and dilutes the unique cyclopentadiene molecule to prevent redimerization and reduced yield of cyclopentadiene. The overload current of this step is a stream consisting of cyclopentane and cyclopentadiene. This stream is subsequently diluted with recycled liquid rich in cyclopentane obtained from the high pressure separating drum. The purpose of the dilution is to minimize the dimerization of the cyclopentadiene and to allow controlling the exothermic process in the subsequent hydrotreatment reactors. The cyclopentadiene / cyclopentane stream is then pumped into a reactor and combined with a stoichiometric excess of hydrogen contained in a stream of treatment gas. It is then passed through a palladium on alumina catalyst where most of the hydrogenation reaction occurs, converting most of the cyclopentadiene to cyclopentane. The tributary of the first reactor flows to a second reactor containing a massive nickel catalyst wherein any remaining carbon (ie cyclopentane) is saturated. The affluent of the fully hydrogenated nickel reactor is cooled and enters a high pressure separating drum. The steam in this drum, which mainly contains hydrogen but also contains certain cyclopentane vapor, is brought into contact with the feed stream of the dicyclopen-thiaphium in an absorption tower to minimize losses of the cyclopentane. A portion of the liquid product of the high pressure separating drum is recycled as described above. The remnant flows to a product separation tower in which any remaining dissolved hydrogen and any compound heavier than cyclopentane are removed. The separating bottoms can be recycled to the disintegration tower of dicyclopentadiene. The process according to the present invention can be described in a better way referring to Figure 1., wherein the 'DCPD' and an aliphatic hydrocarbon fluid of a specific volatility and solvency are fed from tanks 1 and 3 respectively, through conduit 5 towards the distillation tower disintegrating (7) in such a way that the 'DCPD' 'disintegrates to form cyclopentadiene and cyclopentane. A recycle stream of cyclopentane product from a high pressure separating drum (9) is recycled to the tower (7) through the conduit (11). The recycle stream of cyclopentane product aids distillation in the tower (7) and dilutes the single molecule of cyclopentadiene to between 15 and 50% to prevent redimerization and reduction of cyclopentadiene yield. The liquid mixture of cyclopentadiene and cyclopentane is taken as bottoms of the tower (7) through the conduit (13) and is delivered in the separating drum (15) in which it is subsequently diluted with a recycled liquid rich in cyclopentane obtained from the tower of the separation of the product (17) through conduits (19) and (21). The purpose of the dilution in the separating drum is to minimize the dimerization of the cyclopentadiene and to allow control of the exothermic process in the subsequent hydrotreatment reactors. The cyclopentadiene / cyclopentane stream having a cyclopentadiene content of between 15 and 50% is taken from the top of the separating drum (15) through the conduit (23) and mixed with the stoichiometric hydrogen surplus of the conduit (24) . The saturated cyclopentadiene / cyclopentane stream of hydrogen is then sent to the first hydrogenation reactor (25) where it is passed through a palladium on alumina catalyst where most of the hydrogenation reaction occurs, converting most of the cyclopentadiene to cyclopentane. The liquid tributary of the first hydrogenation reactor (25) is taken via the conduit (27) and sent to the upper part of the second hydrogenation reactor (29) containing a massive nickel catalyst wherein any remaining carbon (ie, cyclopentane) is saturated. The fully hydrogenated product stream is taken as liquid bottoms of the reactor (29) through the conduit (31) and cooled by a heat exchanger (33) and subsequently sent to a high pressure separating drum (9). The overload (that is, mainly hydrogen), but also certain cyclopentane vapor) of the separating drum (9) is returned to the tower (7) through the conduit (11), as discussed above, to minimize losses of cyclopentane . The bottoms of the separating drum (9) are taken through the duct (35) and either recycled upstream of the first hydrogenation reactor (25) or sent through the duct (37) to the separation tower of the product (17) where any remaining dissolved hydrogen is removed from the top through the conduit (39). The bottoms of the separation tower (17) are eliminated through the duct (41) and, optionally, are recycled to the tower (7) or purged from the system. The cyclopentane product is recovered from an intermediate section of the separation tower (17) through the conduit (19) and sent to the tank, not shown, or recycled via the conduit (21) to the separating drum (15), as It was discussed above. At this point, the cyclopentane is preferably of a purity of 95%. Some of the main advantages of the high purity cyclopentane product, such as "Exxsol® Cyclopentane", over conventional blowing agents such as low purity cyclopentanes, pentane isomers and hydrofluorocarbons are: (1) the high purity cyclopentane product of the present invention is soluble or capable of mixing with the polyols, while n-pentane and iso-pentane are not soluble in the polyols; (2) the insulation efficiency of the foams formed using high purity cyclopentane product of the present invention is higher than with other pentane isomers for initial and aged R values; (3) the high purity cyclopentane product of the present invention has a much lower diffusion rate of the polyurethane foams than the other pentane isomers; and (4) the high purity cyclopentane product does not have GWP, while the hydrofluorocarbon blowing agents have a higher GWP. The following is a comparison of various properties of blowing agents: HCFC HFC HFC Insufflation agents 141b * 245FA * * 365 *** 95% CP 78% CP Iso-Pen N-Pen Molecular weight 117 134 148 70 70 72 72 Conductivity of 0.005 0.007 0.008 0.0065 0.0068 0.0076 0.0076 thermal vapor BTU in / hr-ft2, at 25 ° C Soluble in polyols Yes Yes Yes Yes No No No Boiling point 32.1 15.4 40 50 50 28 28 Flammability Light None Yes Yes Yes Yes Yes Ozone depletion 0.12 0 0 0 0 0 0 Global warming 0.12 0.24 > 0.20 No No No No Status VOC No No No Yes Yes Yes Yes * CH3CC12F ** CF3CH2CHF2 manufactured by Allied Signal Inc *** CF3CH2CF2CH3 manufactured by Elf Atochem CP denotes that cyclopentane has the general formula C5H10 Iso Pen denotes iso-pentane with a general formula C5H12 N-Pen denotes normal pentane having the general formula C5H12 The mixing capacity of the specially synthesized cyclopentane (SYNCP) of the invention is evidenced in TABLE 1. In addition, the addition of a Potassium catalyst, a tertiary amine amine catalyst, and the normal surfactant-type silicone to the above mixtures of the synthesized cyclopentane (SYNCP) produces clear solutions in the useful ranges of about 13% up to about 30% cyclopentane by weight. In contrast, these same additives do not make clear solutions in any mixing ratio with conventional blowing agents. TABLE 1 (STUDIES OF MISCIBILITY OF THIS CYCLOPENTAN) Weight ratio Cyclopentane of Polyols / Cyclopentane synthesized 80/20 Stable mix 75/25 Stable mix 70/20 Stable mix 50/50 Stable mix 35/65 Stable mix 20/80 Stable mix The mixtures of the high purity cyclopentane according to the present invention were all clear solutions and remained stable . Suitable catalysts (e) for the production of molded articles having a compressed peripheral zone and a cellular core, especially include compounds which greatly accelerate the reaction of the hydroxyl group containing compounds of components (b) and optionally, (c) with the optionally modified organic polyisocyanates (a). Examples include organic metal compounds, preferably organic tin compounds such as the tin (II) salts of organic carboxylic acids, that is tin (II) acetate, tin (II) dioctane, tin (II) ethylhexoate and tin laurate (II), as well as the dialkyltin (IV) salts of organic carboxylic acids, that is, dibutyltin diacetate and dibutyltin dilaurate. The organic metal compounds are used alone or preferably in combination with strong basic amines. Examples which include amines are 2, 3-dimethyl-3,4,5,6-tetrahydropyrimidine, tertiary amines, such as triethylamine, tributylamine, dimethylbenzylamine, N-methylmorpholine, N-ethylmorpholine, N-cyclohexylmorpholine, N, N, N ', N'-tetrarretylethylenediamine, N, N, N', N '-tetramethylbutanediamine, pentamethyldiethylenetriamine, tetramethyldiaminoethyl ester, bis (dimethylaminopropyl) urea, dimethylpiperazine, 1,2-dimethylimidazole, 1-aza-bicyclo- [3.3.0] octane and preferably 1,4-diaza-bicyclo [2.2.2] octane and alkanolamine compounds such as triethanolamine, triisopropanolamine , N-methyl and N-ethyl-diethanolamin and dimethylethanolamine. Suitable catalysts when large excess polyisocyanates are used also include tris (dialkylamino) -s-hexahydrothriazine, especially tris (N, -dimethylamino-propyl) -s-hexahydrotriazine, tetraalkylammonium hydroxides such as tetramethylammonium hydroxide, alkali hydroxides such as sodium hydroxide and alkali alcoholates such as sodium methylate and potassium isopropylate, as well as alkali salts of long chain fatty acids with 10 to 20 carbon atoms and optionally OH groups suspended. 0.001 to 5 weight percent, especially 0.05 to 2 weight percent, of catalysts or combination of catalysts are preferred based on the weight of component (b). Optionally other additives and / or auxiliaries (f) can be incorporated into the reaction mixture to produce the molded articles. Some examples include active surface substances, foam stabilizers, cell regulators, fillers, inks, pigments, flame retardants, hydrolysis preventive agents, fungistatic agents, bacteriostats and mixtures thereof. To produce molded articles, the organic polyisocyanates (a), higher molecular weight compounds are reacted with at least two reactive hydrogens (b) and optional chain extenders and / or crosslinking agents (c) in amounts such that the equivalent ratio of NCO groups of polyisocyanates (a) in relation to the total reactive hydrogens of components (b) and, optionally, (c) are of the order of 1: 0.85-1: 1.25, preferably 1: 0.95-1: 1.15. If the molded articles contain at least certain isocyanurate groups in linked forms, then, conventionally, a proportion of NCO groups or polyisocyanates (a) to the total reactive hydrogens of components (b) and optionally (c) will be 1.5: 1-60 : 1, preferably 0.51-8: 1. Molded articles, especially elastic and flexible integral epidermal foams and articles molded by cellular elastomers are prepared using a pre-polymerization process or preferably a one-shot process with the aid of low pressure technology or more preferably injection molding and high pressure reaction in closed and efficiently heated molds, for example, metal molds made of aluminum, wrought iron or steel, or molds made of fiber reinforced by polyester compositions or epoxy compositions. It has been proven that it is more beneficial to work according to a two component process and incorporate initial components (b), (d), (e) and optionally (c) and (f) into components (A) and use organic polyisocyanates, modified polyisocyanates (a) or mixtures of the polyisocyanates mentioned above as the (B) component optionally including blowing agents (d). The initial components are mixed together at a temperature of 15 to 90 degrees centigrade, more preferably 20 to 30 degrees centigrade and injected into a closed mold optionally under an increased pressure. The mixing can be carried out mechanically using a beater or using a beating screw or even under a high pressure in a countercurrent injection process. The temperature of the mold is usually from 20 to 90 degrees centigrade, more preferably between 30 and 60 degrees centigrade, and more preferably between 45 and 50 degrees centigrade. The molded articles according to the present invention are particularly suitable for use in the manufacture of shoe soles and products for the automotive or recreational vehicle industry, that is, bumper covers, impact protection moldings, and parts such as drip moldings, bumpers, bumpers and extensions for rims, as well as components of engineering casings and rollers. These integral epidermal foams can also be used, for example, in armrests, head rests, safety covers inside automobiles and for bicycle and motorcycle seats and finally as covers for composite foams. Although here we have shown and described various modalities according to our invention, it should be clearly understood that it is susceptible to numerous apparent changes to those skilled in the art. Therefore, we do not want to be limited by the details shown and described, but we try to show all the changes and modifications that fall within the scope of the appended claims.

Claims (23)

1. CLAIMS 1. A method for preparing a molded article, having a compressed peripheral zone and a cellular core, comprising: introducing into a mold container a mixture comprising: (a) an organic and / or modified organic polyisocyanate; (b) at least one compound of higher molecular weight having at least two reactive hydrogen atoms; (c) optionally, a lower molecular weight chain extender agent and / or crosslinking agent; (d) an insufflating agent comprising high purity cyclopentane, substantially free of C6 to C8 hydrocarbons; and (e) a catalyst capable of forming a molded article having a compressed peripheral zone and a cellular core; and reacting said mixture at a temperature, a pressure and for a time lapse sufficient to produce said molded article having a compressed peripheral zone and a cellular core. The method of claim 1, wherein said polyisocyanate is an aliphatic or aromatic polyisocyanate selected from the group consisting of 1,2-dodecane diisocyanate, 2-ethyl-1,4-tetramethylene diisocyanate, 2-methyl-1, 5- pentamethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, l-isocyanate-3, 3, 5-trimethyl-5-isocyanatomethyl -clohexane (isophorone diisocyanate), 2,4-hexahydrotoluene diisocyanate, 2,6-hexahydrotoluene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 2,2'-dicyclohexylmethane diisocyanate, 2,4'-dicyclohexylmethane diisocyanate, 2,4 toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, polyphenylpolymethylene polyisocyanates (polymeric MDI), dimers, trimers and prepolymers thereof, and a mixture thereof . 3. The method of claim 1, wherein said higher molecular weight compound is selected from the group consisting of: polyether polyol, polyester polyol, polythioether polyol, polyester amide, hydroxyfunctional polycarbonate, hydroxyfunctional aliphatic polycarbonate, diol, triol, polyfunctional alcohol, polyether polyamine, diamine, triamine, polyfunctional amine, and a mixture thereof. The method of claim 1, wherein said lower molecular weight chain extender agent or crosslinking agent is an amine or polyfunctional alcohol selected from the group consisting of polyethylene oxide, polypropylene oxide, hydroxy terminated polyester, ethylene glycol, , 3-propanediol, 1, 10-decanediol, 1,2-dihydroxycyclohexane, diethylene glycol, dipropylene glycol, 1,3-dihydroxycyclohexane, 1,4-dihydroxycyclohexane, 1,4-butanediol, 1,6-hexanediol, bis (2-hydroxyethyl) ) hydroquinone, 1, 2,4-trihydroxycyclohexane, 1,3,5-trihydroxycyclohexane, glycerol, trimethyloletanol, trimethylolpropane, and a mixture thereof. The method of claim 1, wherein said high purity cyclopentane comprises cyclopentane in an amount of at least 50 mol%. The method of claim 5, wherein said high purity cyclopentane comprises (a) cyclopentane and (b) n-pentane and / or iso-pentane in a molar ratio of (a) to (b) of between about 50 : 50 to 99: 1. The method of claim 6, wherein said high purity cyclopentane comprises (a) cyclopentane and (b) n-pentane and / or iso-pentane in a molar ratio of (a) to (b) of between about 50 : 50 and 80:20. The method of claim 5, wherein said high purity cyclopentane comprises a mixture of cyclopentane and iso-pentane in a molar ratio of 70:30. The method of claim 6, wherein said high purity cyclopentane comprises (a) cyclopentane and (b) n-pentane and / or iso-pentane in a molar ratio of (a) to (b) of between about 80 : 20 and 99: 1. The method of claim 1, wherein said high purity cyclopentane is substantially free of hexanes. The method of claim 10, wherein said high purity cyclopentane is substantially free of 2,2-di-ethylhexane and its isomers. The method of claim 1, wherein said high purity cyclopentane is prepared from the following steps: (a) disintegrating (cracking) dicyclopentadiene in cyclopentadiene; (b) separating said cyclopentadiene-rich stream from higher boiling liquids; (c) diluting said cyclopentadiene-rich stream with recycled saturates in such a way that the cyclopentadiene content is limited to 15-50%; (d) conducting a first hydrogenation of said cyclopentadiene-rich stream in the presence of hydrogen and a palladium on alumina catalyst, thereby converting a substantial portion of the cyclopentadiene into cyclopentane, and thus forming a cyclopentane-rich stream; (e) conducting a second hydrogenation of said cyclopentane-rich stream from step (d) in the presence of a massive nickel catalyst, wherein any residual olefins are saturated to form a crude cyclopentane product; (f) separating hydrogen from said crude cyclopentane product; and (g) recycling the hydrogen from step (f) to step (d) and / or step (e); and (h) stripping said crude cyclopentane product to form a cyclopentane product having at least about 50% purity. The method of claim 1, wherein said catalyst comprises an organic metal compound and, optionally, a strong basic amine. The method of claim 13, wherein said organic metal compound is an organic tin compound selected from the group consisting of: a tin salt (II) of an organic carboxylic acid, dialkyltin salt (IV) of an organic carboxylic acid , and a mixture of these. The method of claim 14, wherein said organic metal compound is selected from the group consisting of: tin (II) acetate, tin (II) dioctoate, tin (II) ethylhexoate, tin (II) laurate , dibutyltin diacetate (IV), dibutyltin dilaurate (IV), and a mixture of them. 16. The method of claim 13, wherein said strong basic amine is selected from the group consisting of: 2,3-dimethyl-3, 4,5,6-tetrahydropyrimidine, triethylamine, tributylamine, dimethylbenzylamine, N-methylmorpholine, N-ethylmorpholine, N-cyclohexylmorpholine, N, N, N ', N' -tetramethylethylenediamine, N, N, N ',' -tetramethylbutanediamine, pentamethyldiethylenetriamine, tetramethyldiaminoethyl ester, bis (dimethylaminopropyl) urea, dimethylpiperazine, 1,2-dimethylimidazole, 1-aza-bicyclo [3.3.0] octane, 1,4-diaza-bicyclo [2.2.2] octane, triethanolamine, triisopr-panolamine, N-methyldiethanolamine, N-ethyldiethanolamine, dimethylethanolamine, tris (dialkylamino) -s-hexahydrotriacines , tris (N, N-dimethylaminopropyl) -s-hexahydrotriazine, and a mixture thereof. The method of claim 1, wherein the equivalent ratio of isocyanate groups in (a) to the total of active hydrogen groups in (b) and (c) is from about 1: 0.85 to 1: 1.25. 18. The method of claim 1, wherein said molded article is substantially free of unreacted isocyanate. 19. The method of claim 1, further comprising an additive, said additive being selected from the group consisting of: a surfactant, a foam stabilizer, a cell regulator, a filler, a pigment, a dye, a retardant Flame, an agent that prevents hydrolysis, a fungistatic, a bacteriostatic agent, and a mixture of them. 20. A molded article prepared by the process of claim 1. 21. A process for the preparation of a flexible integral epidermal foam, comprising: preparing a mixture comprising: (a) an organic and / or modified organic polyisocyanate; (b) at least one compound of higher molecular weight having at least two reactive hydrogen atoms; (c) optionally, a lower molecular weight chain extender agent and / or crosslinking agent; (d) an insufflating agent comprising high purity cyclopentane substantially free of C6 to C8 hydrocarbons; Y (e) a catalyst capable of forming a flexible integral epidermal foam; and reacting said mixture at a temperature, a pressure and for a sufficient time to produce a flexible integral epidermal foam. 22. An article in the form of a flexible integral epidermal foam, prepared by the process of claim 21. 23. A process for the preparation of a cellular elastomer, comprising: preparing a mixture comprising: (a) a polyisocyanate organic and / or modified organic; (b) at least one compound of higher molecular weight having at least two reactive hydrogen atoms; (c) optionally, a lower molecular weight chain extender agent and / or crosslinking agent; (d) an insufflating agent comprising high purity cyclopentane substantially free of C6 to C8 hydrocarbons; Y (e) a catalyst capable of forming a cellular elastomer; and reacting said mixture at a temperature, a pressure and for a sufficient time to produce a cellular elastomer. 24. An article in the form of a cellular elastomer, prepared by the process of claim 23.