Method for converting solid polyurethane moldings

Abstract

Provided herein are processes for the continuous production of liquid polyurethane prepolymers from preformed solid polyurethane articles comprising a toluene diisocyanate composition under defined conditions. These processes include a process for producing polyurethane prepolymers, a process for regenerating preformed polyurethane articles, and a process for converting solid polyurethane articles into liquid polyurethane materials.

Description

[Technical field]

[0001] The present invention relates generally to preformed solid polyurethane articles, and more particularly to a method for converting preformed solid polyurethane articles into liquid polyurethane prepolymers. [Background technology]

[0002] Polyurethanes are a class of materials that offer unique physical properties and are suitable for use in a variety of applications. Polyurethanes are available in non-cellular, cellular or microcellular forms and can be further classified as rigid, semi-rigid or flexible polyurethanes. Depending on the formulation used to form the polyurethane, polyurethanes can also be classified as thermoplastic or thermosetting polymers, as well as elastomeric or non-elastomeric polymers.

[0003] Two types of polyurethanes used in a wide variety of polyurethane molded articles are thermoplastic polyurethanes (TPUs) and cellular foams (including, for example, microcellular foams (MCUs)). TPUs are block copolymers containing hard and soft segments (or domains) formed by the reaction of diisocyanates with short-chain and long-chain diols. TPUs are typically processed in extruders or injection molding equipment to produce polyurethane molded articles used in a variety of applications, including but not limited to automotive, footwear, and medical applications. Cellular foams are typically processed by mixing liquid ingredients in a mold under low pressure in the presence of a blowing agent to produce foamed polyurethane molded articles also used in automotive and footwear applications. MCU foams are also formed by a two-step process, as known in the art, in which an isocyanate prepolymer is formed by the exothermic reaction of a hydroxyl-functional polymer containing two or more hydroxyl groups with a diisocyanate. A portion of the isocyanate prepolymer reacts with water to produce carbon dioxide off-gassing, and the release of the off-gassing produces a cellular structure. In some cases, an auxiliary blowing agent is included. The cellular structure is cured to form MCU foam therein.

[0004] As TPUs used to form polyurethane molded articles, and cellular foams such as MCU foams, become more widely used, the potential for harmful environmental impacts also increases. Typically, after use, polyurethane molded articles are disposed of in landfills, potentially creating harmful environmental impacts. Polyurethane molded articles can take the form of trimmings, slabs, or molded parts (the molded parts are either actually used for their intended purpose or disposed of prior to use for various reasons) and may be discarded after off-spec production or end use. Because disposal of polyurethane molded articles can create harmful environmental impacts, it would be advantageous to reclaim these polyurethane molded articles.

[0005] Various methods of regenerating polyurethane molded articles are known in the prior art, including regenerating polyurethane molded articles from the aforementioned TPU and cellular foam. These regeneration methods generally include mechanical regeneration, which reuses the polyurethane molded article in its polymeric form, and chemical regeneration, which breaks down the polyurethane molded article into various chemical components. Common examples of mechanical regeneration of polyurethane molded articles include, but are not limited to, recombining, compacting, regrinding, pulverizing (i.e., pulverizing or grinding) of soft foam, and any combination thereof. One specific example of a mechanical regeneration method is disclosed in U.S. Patent No. 5,908,894 to Genz et al. More specifically, Genz et al. disclose a method of preparing a TPU compound by recycling pulverized MCU. More specifically, the process prepares a TPU compound by reacting an isocyanate, a compound reactive to an isocyanate, and optionally additives such as chain extenders, catalysts, coagents, and plasticizers with pulverized fine-cell foam. Common examples of chemical regeneration of polyurethane molded articles include, but are not limited to, hydrogenation, pyrolysis, hydrolysis, glycolysis, alcoholysis, acidolysis, cleavage (thermal or alkaline cleavage), aminolysis, solvolysis, and any combination thereof. Many of these chemical regeneration processes are time-consuming and very costly. In addition, certain chemical regeneration processes utilize or result in the production of other chemical compounds, such as aromatic amines. These compounds may be mixed with the desired product and require separation and disposal, increasing environmental concerns as well as costs.

[0006] Preformed polyurethane parts can also be recycled in batches. Batch recycling of polyurethane parts using isocyanates is difficult to scale up because it uses large amounts of toluene diisocyanate (TDI) to allow processing of preformed polyurethane parts with high volume but low density (i.e., light weight). Operating temperature and foam addition rate are limiting factors for batch recycling of polyurethane foam using toluene diisocyanate. Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention provides an improved process for reclaiming preformed polyurethane articles using TDI by creating a continuous process that allows mixing of the preformed polyurethane article and the TDI composition in an extruder setting with the appropriate residence time to liquefy the preformed polyurethane article to produce a soluble TDI-capped polyurethane prepolymer. Designing a continuous process reduces TDI during the process, allowing for better control without limiting throughput compared to batch processes. Problems with handling large amounts of low density preformed polyurethane articles that limit batch process time are also solved by using a continuous process, and chemical measures have been implemented to speed up and stabilize the resulting polyurethane prepolymer. [Means for solving the problem]

[0008] The present invention is based on the breakthrough discovery that isocyanate-functional liquid prepolymers can be produced in a continuous process by preheating a TDI composition in an external vessel and simultaneously contacting a preformed solid polyurethane article with the preheated TDI composition.

[0009] In one embodiment, the present invention provides a method for producing a polyurethane prepolymer comprising the steps of: a) processing and / or densifying a preformed polyurethane article; b) preheating a toluene diisocyanate composition at a temperature in the range of about 130 to 165° C.; and c) contacting the processed and / or densified preformed polyurethane article with the toluene diisocyanate composition, thereby producing a polyurethane prepolymer.

[0010] In one embodiment, the toluene diisocyanate composition comprises about 50%-75% toluene-2,4-diisocyanate and about 10%-15% toluene-2,6-diisocyanate. In another embodiment, the toluene diisocyanate composition comprises about 50%-75% toluene-2,4-diisocyanate and about 15%-20% toluene-2,6-diisocyanate. In a further embodiment, the toluene diisocyanate composition comprises about 60%-80% toluene-2,4-diisocyanate and about 10%-20% toluene-2,6-diisocyanate. In one embodiment, the preformed polyurethane article is a polyurethane foam. In some embodiments, the processing and / or densifying step is performed before, after, or simultaneously with the preheating step. In other embodiments, increasing the preheat temperature reduces the processing time. In one embodiment, the polyurethane foam is selected from the group consisting of microcellular foam, semi-rigid foam, molded foam, and any combination thereof. In some embodiments, the foam comprises a polyol having a molecular weight in the range of about 1000-3600 Da. In other embodiments, the step of processing and / or densifying the foam comprises grinding the foam to obtain chopped foam. In another embodiment, the chopped foam pieces have a size in the range of about 500 μm-5 mm. In some embodiments, the chopped foam pieces have a size of about 1 mm. In various embodiments, the step of processing and / or densifying comprises using a grinder, processor, shredder, granulator, crusher, compactor, or pulverizer. In one embodiment, the production is a continuous process. In another embodiment, the preheat temperature is in the range of about 160-165° C. In one embodiment, the contacting step comprises contacting about 1-30% w / w of the foam with the polyurethane composition. In one embodiment, the method further comprises agitating the preformed polyurethane article and the heated polyurethane composition. In another embodiment, the temperature of the toluene diisocyanate composition is maintained at a temperature in the range of about 130 to 165° C. during the contacting step. In a further embodiment, a catalyst is added after step (b).

[0011] In another embodiment, the present invention provides a method for regenerating a preformed polyurethane article, comprising: (a) processing and / or densifying a preformed polyurethane article; (b) heating a toluene diisocyanate composition at a temperature in the range of about 130 to 165° C.; (c) contacting the preformed polyurethane article with the heated toluene diisocyanate composition of (b); and (d) producing a soluble isocyanate-terminated liquid prepolymer, thereby regenerating the preformed polyurethane article.

[0012] In one embodiment, the preheat temperature ranges from about 160-165°C. In another embodiment, the preformed polyurethane article is a polyurethane foam. In another embodiment, the method further comprises adding a catalyst after step (b). In some embodiments, the catalyst comprises dibutyltin dilaurate (DABCO T12). In other embodiments, the method further comprises adding diethylene glycol bischloroformate (DIBIS). In various embodiments, the DIBIS mitigates the solidification of the prepolymer over time induced by DABCO T12. In some embodiments, the DIBIS prevents the degradation of prepolymer stability induced by DABCO T12. In some embodiments, the toluene diisocyanate composition is selected from the group consisting of a polyurethane composition comprising about 50%-75% toluene-2,4-diisocyanate and about 10%-15% toluene-2,6-diisocyanate; a polyurethane composition comprising about 50%-75% toluene-2,4-diisocyanate and about 15%-20% toluene-2,6-diisocyanate; and a polyurethane composition comprising about 60%-80% toluene-2,4-diisocyanate and about 10%-20% toluene-2,6-diisocyanate.

[0013] In a further embodiment, the present invention provides a method for converting a preformed polyurethane article into a liquid polyurethane material comprising the steps of: (a) processing and / or densifying the preformed polyurethane article; (b) heating a toluene diisocyanate composition at a temperature in the range of about 130-165°C; (c) contacting the preformed polyurethane article with the heated toluene diisocyanate composition of (b); and (d) producing a soluble isocyanate-terminated liquid prepolymer, thereby converting the preformed polyurethane article into a liquid polyurethane material.

[0014] In one embodiment, the preheat temperature ranges from about 160-165° C. In another embodiment, converting the preformed polyurethane article includes producing a polyurethane prepolymer. In some embodiments, the prepolymer is used in the production of industrial chemicals and / or industrial polymers. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 illustrates a typical polyurethane foam conversion process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The present invention is based on the breakthrough discovery that isocyanate-functional liquid prepolymers can be produced by preheating a TDI composition in an external vessel and simultaneously contacting a preformed solid polyurethane article with the preheated TDI in a continuous process.

[0017] Before describing the compositions and methods of the present invention, it is to be understood that the invention is not limited to the particular compositions, methods, and experimental conditions described, as such compositions, methods, and conditions may vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims.

[0018] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Thus, for example, reference to a "method" includes one or more methods and / or steps of the type described herein that will be apparent to those of skill in the art upon reading this disclosure and so forth.

[0019] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.Methods and materials similar or equivalent to those described herein can be used to carry out or test the present invention, but it will be understood that modifications and variations are within the spirit and scope of the present disclosure.Preferred methods and materials are described herein.

[0021] Batch regeneration of preformed solid polyurethane parts with isocyanate uses large amounts of polyurethane part and toluene diisocyanate (TDI), making it difficult to scale up. Operating temperature and rate of addition of polyurethane part are limiting factors for batch regeneration of polyurethane parts with toluene diisocyanate. Regeneration of more than 1 wt.% of polyurethane part in isocyanate is difficult because polyurethane part cannot be added completely due to the low density and volume of polyurethane part. Above this amount, liquid is absorbed into the polyurethane part and the process is severely limited due to poor heat transfer. Therefore, polyurethane part must be added slowly to facilitate good liquid contact with the polyurethane part by external heating. Reaction times at 130°C are long due to slow dissolution of polyurethane part in liquid medium, greatly limiting the amount of polyurethane part that can be added per unit time. Running the reaction at 165°C allows for almost instantaneous dissolution / reaction of polyurethane part to produce soluble isocyanate-terminated prepolymer. However, the thermal event in this process can occur at temperatures as low as 180 °C, with the thermal energy and pressure generation maximal at 200 °C. This is problematic for scale-up, since most of the potential chemical energy of this thermal event is contained in the TDI.

[0022] In one embodiment, the present invention provides a method of producing a polyurethane prepolymer, comprising the steps of processing and / or densifying a preformed polyurethane article, preheating a toluene diisocyanate composition at a temperature in the range of about 130-165° C., and contacting the processed and / or densified preformed polyurethane article with the toluene diisocyanate composition, thereby producing the polyurethane prepolymer. The preformed polyurethane article may be a reclaimed polyurethane article.

[0023] The terms "preformed polyurethane article" and "solid polyurethane article" are used interchangeably and refer to a polyurethane article that is formed (i.e., preformed) as a reaction product of an isocyanate component (alternatively referred to herein as an isocyanate) and an isocyanate-reactive component.

[0024] The term "recycled" as used below in the phrase "recycled polyurethane molded article" generally refers to the use of previously formed ("preformed") polyurethane molded articles or materials. In other words, any previously formed polyurethane molded article or material may be used, including those previously used for their intended purpose (e.g., footwear, automobile headliners or front panels, etc.), or those that were not otherwise used for their intended purpose (i.e., unused materials, such as scrap or unused commercial products, etc.). In other words, the only requirement for a polyurethane molded article to be considered a "recycled polyurethane molded article" as used herein is that it is a preformed polyurethane molded article or material and is currently usable. Recycled polyurethane molded articles may be in the form of conventional, slab, or molded soft foams; rigid, semi-rigid open and closed foams; microcellular polyurethane (MCU) foams, thermoplastic polyurethanes (TPUs), and any combination thereof.

[0025] The isocyanate-functional polymer component can be formed by reacting the recycled polyurethane molded article in liquid form with an isocyanate component having a known isocyanate functional group content (NCO content) to form an isocyanate-functional polymer component having a lower NCO content than the isocyanate component. The isocyanate-functional polymer component formed as above can then be used to form a new polyurethane molded article or a new polyurethane foam molded article according to other embodiments of the present disclosure. The isocyanate-functional polymer component and new polyurethane molded article of the present disclosure, as well as the related methods for producing the polyurethane prepolymer component and related new polyurethane molded articles, are described in more detail below.

[0026] As described above, the recycled polyurethane molded article is used to form an isocyanate-functional polymer component. The isocyanate-functional polymer component can be formed by reacting the recycled polyurethane molded article with an isocyanate component having a known isocyanate functional group content (NCO content) to form an isocyanate-functional polymer component having a lower NCO content than the isocyanate component. As used herein, "NCO content" refers to the isocyanate functional group content of a particular isocyanate component measured according to ISO 14896 / 3 or the ASTM equivalent ASTM D2572 (hereinafter collectively referred to as ASTM D2572).

[0027] A recycled polyurethane article is a polyurethane article or material that has previously been formed (i.e., preformed) as a reaction product between an isocyanate component (alternatively referred to herein as an isocyanate) and an isocyanate-reactive component. Preferably, the recycled polyurethane article of the present disclosure is in the form of a ground polyurethane article. Ground polyurethane article refers to a polyurethane article that is in powder form or in the form of small particles or fragments.

[0028] Typically, the systems used to form such recycled polyurethane articles are provided in two or more separate components, such as an isocyanate component and an isocyanate-reactive (or resin) component, i.e., as a two-component (or 2K) system, as further described below. It will be understood that references to isocyanate components and isocyanate-reactive components used herein are merely for establishing a reference point for the placement of the individual components of the system and for establishing parts by weight. Thus, recycled polyurethane articles should not be construed as being limited to only 2K systems. For example, the individual components of a system for preforming recycled polyurethane articles can all be kept distinct from one another.

[0029] As described above, the recycled polyurethane molded article is preformed as a reaction product of an isocyanate-reactive component and an isocyanate component. It will be understood that one or more isocyanates can be reacted with one or more isocyanate-reactive components to form the recycled polyurethane molded article. It will also be understood that the isocyanate component is not limited to any particular genus of isocyanate, for example, the isocyanate component can include monomeric isocyanates, polymeric isocyanates, and mixtures thereof. Additionally, the isocyanate component can include a prepolymer, for example, a hydroxyl-functional polymer reacted with an excess of isocyanate.

[0030] In certain aspects, the isocyanate-reactive component includes a hydroxyl-functional polymer component (alternatively referred to as a polyol) that is reactive with the isocyanate functional group of the isocyanate component. It will be understood that the isocyanate-reactive component can include one or more hydroxyl-functional polymers. Typically, the isocyanate-reactive component includes a combination of hydroxyl-functional polymers. The hydroxyl-functional polymer includes one or more OH functional groups, typically at least two OH functional groups. The hydroxyl-functional polymer typically includes conventional hydroxyl-functional polymers, such as polyether hydroxyl-functional polyether polymers and / or hydroxyl-functional polyester polymers. Other suitable hydroxyl-functional polymers include, but are not limited to, biopolyols, such as soybean oil, castor oil, soybean protein, rapeseed oil, and the like, and combinations thereof.

[0031] In some embodiments, the isocyanate-reactive component for forming the recycled polyurethane molded article comprises a hydroxyl-functional polyether polymer. Suitable hydroxyl-functional polyether polymers for the purposes of this disclosure include, but are not limited to, products obtained by polymerization of cyclic oxides, such as ethylene oxide (EO), propylene oxide (PO), butylene oxide (BO) or tetrahydrofuran, in the presence of a multifunctional initiator. Suitable initiator compounds contain multiple active hydrogen atoms and include water, butanediol, ethylene glycol, propylene glycol (PG), diethylene glycol, triethylene glycol, dipropylene glycol, ethanolamine, diethanolamine, triethanolamine, toluenediamine, diethyltoluenediamine, phenyldiamine, diphenylmethanediamine, ethylenediamine, cyclohexanediamine, cyclohexanedimethanol, resorcinol, bisphenol A, glycerol, trimethylolpropane, 1,2,6-hexanetriol, pentaerythritol, and combinations thereof. Other suitable hydroxyl functional polyether polymers include polyether diols and triols, such as polyoxypropylene diols and triols, poly(oxyethyleneoxypropylene) diols and triols, obtained by simultaneous or sequential addition of ethylene and propylene oxide to a difunctional or trifunctional initiator. Copolymers having an oxyethylene content of about 5 to about 90% by weight, based on the weight of the hydroxyl functional polyether polymer component, can also be used, and the hydroxyl functional polyether polymer can be a block copolymer, a random / block copolymer, or a random copolymer. Still other suitable hydroxyl functional polyether polymers include polytetramethylene glycol obtained by polymerization of tetrahydrofuran. In one embodiment, the hydroxyl functional polyether polymer is a polyether triol. In this embodiment, the hydroxyl number of the polyether triol is 20 to 90, more typically 40 to 70, and most typically 50 to 60 mg KOH / g.Further, the polyether triol of this embodiment typically has a weight average molecular weight of from 1,000 to 10,000, more typically from 2,000 to 6,000, and most typically from 2,500 to 3,500 g / mole. In this embodiment, the hydroxyl functional polyether polymer is typically present in the isocyanate-reactive component in an amount of greater than 10, more typically greater than 50, even more typically from 75 to 100, and most typically from 85 to 100 parts by weight, based on 100 parts by weight of total hydroxyl functional polymer present in the isocyanate-reactive component.

[0032] In another embodiment, the isocyanate-reactive component comprises a graft polyol. The graft polyol is a dispersed polymer solid that is chemically grafted to a carrier polyol. More specifically, the graft polyol comprises a carrier polyol and particles of copolymerized styrene and acrylonitrile, the particles of copolymerized styrene and acrylonitrile being dispersed in the carrier polyol as described in more detail below. The graft polyol typically has a nominal functionality of 2 to 4, more typically 2.5 to 3.5, and typically has a hydroxyl number of 10 to 100, more typically 15 to 50, and most typically 20 to 35 mg KOH / g. Typically, the carrier polyol of the graft polyol is a hydroxyl-functional polyether polymer. The carrier polyol may be any hydroxyl-functional polyether polymer known in the art, and preferably serves as the continuous phase for the dispersed copolymerized styrene and acrylonitrile particles. That is, particles of copolymerized styrene and acrylonitrile are dispersed in a carrier polyol to form a dispersion, i.e., to form a graft polyol. The particles of copolymerized styrene and acrylonitrile are typically dispersed in the carrier polyol in an amount of from 10 to 70, more typically from 15 to 60, and most typically from 20 to 55 parts by weight, based on 100 parts by weight of the graft polyol. When present, the graft polyol is typically present in the isocyanate-reactive component in an amount of from 5 to 100 parts by weight, more typically from 10 to 90 parts by weight, and most typically from 15 to 80 parts by weight, based on 100 parts by weight of the total polyol present in the isocyanate-reactive component.

[0033] In yet another aspect, the isocyanate-reactive component comprises a graft polyol and a hydroxyl-functional polyether polymer having a functionality greater than 2 and a hydroxyl number of 15 to 100, more typically 20 to 50, and most typically 25 to 35 mgKOH / g. A non-limiting example of a hydroxyl-functional polyether polymer of this embodiment is a primary hydroxyl-terminated polyether triol. When present, the polyether polyol is typically present in the isocyanate-reactive component in an amount of 5 to 100 parts by weight, more typically 10 to 75 parts by weight, and most typically 15 to 45 parts by weight, based on 100 parts by weight of the total polyol present in the isocyanate-reactive component. When both the graft polyol and the hydroxyl-functional polyether polymer are present in the isocyanate-reactive component, they are typically present in a ratio of 1:2 to 6:1, more typically 1:1 to 5:1, and most typically 2:1 to 4:1.

[0034] The isocyanate-reactive component used to preform the recycled polyurethane article typically includes one or more crosslinking agents. When utilized in the isocyanate-reactive component, the crosslinking agent generally allows for phase separation between the copolymer segments of the formed recycled polyurethane article. That is, the recycled polyurethane article typically includes both hard urea copolymer segments and soft polyol copolymer segments. The crosslinking agent typically chemically and physically links the hard urea copolymer segments to the soft polyol copolymer segments. Thus, the crosslinking agent is usually present in the isocyanate-reactive component to modify the hardness, increase the stability, and reduce the shrinkage of the preformed recycled polyurethane article. One non-limiting example of a suitable crosslinking agent is diethanolamine.

[0035] The isocyanate-reactive component used to preform the recycled polyurethane article also typically includes one or more catalysts. The catalyst is typically present in the isocyanate-reactive component to catalyze the reaction between the isocyanate functional group of the isocyanate and the hydroxyl functional group of the isocyanate-reactive component. It will be understood that the catalyst is typically not consumed in the exothermic reaction between the isocyanate and the hydroxyl functional polymer component used to preform the recycled polyurethane article. More specifically, the catalyst typically participates in the exothermic reaction but is not consumed in the exothermic reaction. The catalyst can include any suitable catalyst or mixture of catalysts known in the art. Examples of suitable catalysts include, but are not limited to, gelling catalysts, such as amine catalysts in dipropylene glycol; blowing catalysts, such as bis(dimethylaminoethyl)ether in dipropylene glycol; and metal catalysts, such as tin, bismuth, lead, and the like. The isocyanate-reactive component used to preform the recycled polyurethane article, particularly the preformed recycled polyurethane foam article, also typically includes one or more surfactants. The surfactant typically assists in homogenization of the blowing agent and the hydroxyl functional polymer component and regulates the cell structure of the preformed regenerated polyurethane foam. The surfactant may include any suitable surfactant or mixture of surfactants known in the art. Non-limiting examples of suitable surfactants include various silicone surfactants, salts of sulfonic acids such as alkali metal and / or ammonium salts of oleic acid, stearic acid, dodecylbenzene or dinaphthylmethane disulfonic acid and ricinoleic acid, foam stabilizers such as siloxane oxyalkylene copolymers and other organopolysiloxanes, oxyethylated alkylphenols, oxyethylated fatty alcohols, paraffin oil, castor oil, castor oil esters and ricinoleic acid esters, and cell regulators such as paraffins, fatty alcohols and dimethylpolysiloxanes. A specific, non-limiting example of a surfactant is silicone glycol copolymer.

[0036] The isocyanate-reactive component used to preform the recycled polyurethane molded article may optionally include one or more additives. Additives suitable for purposes of the present disclosure include, but are not limited to, chain extenders, chain terminators, processing additives, adhesion promoters, antioxidants, defoamers, antifoamers, water scavengers, molecular sieves, fumed silica, UV stabilizers, fillers, thixotropic agents, silicones, colorants, inert diluents, and combinations thereof. If included, additives may be included in the isocyanate-reactive component in various amounts.

[0037] When the preformed recycled polyurethane article is in the form of a foam (i.e., a preformed recycled polyurethane foam article), the isocyanate and the isocyanate-reactive component are reacted in the presence of a blowing agent to form the preformed recycled polyurethane foam article. The blowing agent can be a physical blowing agent, a chemical blowing agent, or a combination of a physical blowing agent and a chemical blowing agent.

[0038] The preformed recycled polyurethane foam used in this application may be "flexible polyurethane foam" or "rigid polyurethane foam." As used herein, the term "flexible polyurethane foam" refers to a particular type of polyurethane foam and is contrasted with "rigid polyurethane foam."

[0039] The preformed recycled polyurethane foam used in this application may be in the form of "semi-rigid flexible polyurethane foam" (SRU), which contains attributes of both the "flexible polyurethane foam" and "rigid polyurethane foam" described above.

[0040] In certain non-limiting embodiments, the preformed recycled polyurethane foam article is a microcellular polyurethane (MCU) foam, it being understood that the MCU foam may also include additional components other than MCU.

[0041] The ground MCU foam can be obtained from a supplier. In another embodiment, the MCU foam can be provided in a non-powdered form (i.e., non-ground) and ground to produce the ground MCU foam. In this latter case, the MCU foam can be obtained from a pre-formed MCU foam body or the material can be obtained from virgin material.

[0042] Preformed MCU foam as described above is distinguished from virgin material in that the preformed MCU foam is initially formed for another use. In certain embodiments, the reclaimed MCU foam originates as a slab, trimming, or molded part, or is sourced from a waste stream of a manufacturing process. Additionally, the reclaimed MCU foam may be sourced from multiple sources, so that the reclaimed MCU foam may include a combination of various MCU foams, as described in more detail below. In contrast, virgin material is made specifically to produce MCU foam, sourced from a product stream, and then optionally pulverized to form pulverized reclaimed MCU foam. Because the virgin material is prepared solely for use in forming the isocyanate prepolymers and polyurethane elastomers (described below) of the present disclosure, the virgin material typically includes only one type of MCU foam.

[0043] As known in the art, MCU foam is formed by a two-step process. First, an isocyanate prepolymer is formed by exothermic reaction of a hydroxyl-functional polymer containing two or more hydroxyl groups with a diisocyanate. Next, the isocyanate prepolymer reacts with water to produce carbon dioxide off-gas. As the carbon dioxide off-gas is released, a cellular structure is produced. The cellular structure is then cured, thereby completing the formation of the MCU foam.

[0044] The MCU foam may include methyldiphenyl diisocyanate-based foam, naphthalene diisocyanate-based foam, tolidine diisocyanate-based foam, and combinations thereof. For example, as alluded to above, if the MCU foam is virgin material or from one source, the MCU foam is typically only methyldiphenyl diisocyanate-based foam or naphthalene diisocyanate-based foam or tolidine diisocyanate-based foam. Alternatively, in another embodiment, the MCU foam may be a combination of methyldiphenyl diisocyanate-based foam, naphthalene diisocyanate-based foam, and tolidine diisocyanate-based foam, especially if the MCU foam is recycled MCU foam. For example, when MCU foam is reclaimed from a combination of slabs, trimmings, and moldings, or obtained from multiple sources, the MCU foam is typically a combination of methyldiphenyldiisocyanate-based foam, naphthalene diisocyanate-based foam, and tolidine diisocyanate-based foam.

[0045] After pulverization, the particle size of the ground polyurethane molding based on MCU foam is preferably 0.5-10 mm. Alternatively, as described above, the ground polyurethane molding may be provided as a pre-manufactured product, in which case the above steps are not necessary. The resulting ground polyurethane molding based on MCU foam (i.e., ground MCU foam) typically has a melting temperature of at least 100-350°C (Celsius), more preferably at least 250°C.

[0046] After the MCU foam-based ground polyurethane molded article is obtained, substantially all of the moisture can be removed from the ground polyurethane molded article before use in the present disclosure. More specifically, moisture is typically removed from the MCU foam-based ground polyurethane molded article until the moisture content is 0.03% or less. Typically, moisture is removed from the MCU foam-based ground polyurethane molded article by drying in an oven for at least 8 hours, although an open heat source may be used to remove moisture. After the moisture is substantially removed, the MCU foam-based ground polyurethane molded article may be stored under vacuum. Alternatively, a desiccant may be added, or a combination of storage under vacuum and addition of a desiccant may be used. After substantially all of the moisture is removed, the MCU foam-based ground polyurethane molded article is suitable for use in forming an isocyanate prepolymer.

[0047] Exemplary commercially available MCU foams that can be used as polyurethane molded articles or ground polyurethane molded articles of the present disclosure include the Cellasto® series MCU foam products commercially available from BASF Corporation of Florham Park, N.J. Alternatively, the MCU foam can be obtained from commercially available products that incorporate MCU foam, such as footwear, automotive headliners, automotive front panels, and the like.

[0048] In certain alternative embodiments, the recycled polyurethane article, typically a ground recycled polyurethane article, is a thermoplastic polyurethane (TPU).

[0049] The TPU of the present disclosure is based on the reaction product of a polyol component and an isocyanate-functional component such as a diisocyanate. Exemplary TPUs can be selected from the group of polyester-based TPUs, polyether-based TPUs, polybutadiene diol-based TPUs, dimer diol-based TPUs, polyTHF-based TPUs, and combinations thereof. Typically, when both polyester-based TPUs and polyether-based TPUs are present, the polyester-based TPUs and polyether-based TPUs are present in a ratio of 1:9 to 9:1, more preferably in a ratio of 1:7 to 7:1, and most preferably in a ratio of 1:5 to 5:1.

[0050] The polyester-based TPU is formed as a reaction product of a polyester polyol and a diisocyanate. A polyester polyol suitable for producing the polyester-based TPU may include a reaction product of a dicarboxylic acid and a glycol having at least one primary hydroxyl group. A dicarboxylic acid suitable for producing the polyester polyol may be selected from the group of, but is not limited to, adipic acid, methyl adipic acid, succinic acid, suberic acid, sebacic acid, oxalic acid, glutaric acid, pimelic acid, azelaic acid, phthalic acid, terephthalic acid, isophthalic acid, and combinations thereof. A glycol suitable for producing the polyester polyol may be selected from the group of, but is not limited to, ethylene glycol, butylene glycol, hexanediol, bis(hydroxymethylcyclohexane), 1,4-butanediol, diethylene glycol, 2,2-dimethylpropylene glycol, 1,3-propylene glycol, and combinations thereof. Suitable diisocyanates for producing polyester-based TPUs include, but are not limited to, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, ethylene diisocyanate, ethylidene diisocyanate, propylene diisocyanate, butylene diisocyanate, cyclopentylene-1,3-diisocyanate, cyclohexylene-1,4-diisocyanate, cyclohexylene-1,2-diisocyanate, 2,4-toluylene diisocyanate, 2,6-toluylene diisocyanate, 2,2-diphenylpropane-4,4'-diisocyanate, fluorophenyl di ... The isocyanate may be selected from the group consisting of phenylene diisocyanate, m-phenylene diisocyanate, xylylene diisocyanate, 1,4 naphthylene diisocyanate, 1,5-naphthylene diisocyanate, diphenyl-4,4'-diisocyanate, azobenzene-4,4'-diisocyanate, diphenylsulfone-4,4'-diisocyanate, dichlorohexamethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, l-chlorobenzene-2,4-diisocyanate, furfurylidene diisocyanate, and combinations thereof.In addition, the polyester-based TPU may also include the reaction product of a suitable chain extender. Suitable chain extenders may be selected from the group of diols including, but not limited to, ethylene glycol, propylene glycol, butylene glycol, 1,4-butanediol, butenediol, butynediol, xylylene glycol, amylene glycol, 1,4-phenylene-bis-hydroxyethyl ether, 1,3-phenylene-bis-hydroxyethyl ether, bis(hydroxymethyl-cyclohexane), hexanediol, and thiodiglycol; diamines including, but not limited to, ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, cyclohexanediamine, phenylenediamine, tolylenediamine, xylylenediamine, 3,3'dichlorobenzidine, and 3,3'-dinitrobenzidine; alkanolamines such as ethanolamine, aminopropyl alcohol, 2,2-dimethylpropanolamine, 3-aminocyclohexyl alcohol, and paminobenzyl alcohol; and combinations thereof. Specific examples of polyester-based TPUs suitable for purposes of this disclosure include Elastollan® 600 series polyester-based TPU resins available from BASF Corporation, Florham Park, New Jersey. Polyether-based TPUs include the reaction product of a polyether polyol and a diisocyanate. Suitable diisocyanates include any of the diisocyanates mentioned above as suitable for making polyester-based TPU resins. Glycols suitable for making polyether-based TPUs may be selected from the group of, but are not limited to, polytetramethylene glycol, polyethylene glycol, polypropylene glycol, and combinations thereof. As with polyester-based TPU resins, polyether-based TPUs may also include the reaction product of a suitable chain extender, which are also suitable for making polyether-based TPU resins. Specific examples of suitable polyether-based TPU resins include Elastollan® 1100 series polyether-based TPU resins available from BASF Corporation, Florham Park, New Jersey.Similar to the MCU foams described above, the TPUs of the present disclosure can be milled after production to form ground TPUs. Alternatively, the TPUs may be provided by a supplier as ground TPUs for use in the present disclosure. Thus, depending on the initial chemical composition of the TPU, the ground TPUs of the present disclosure can be ground polyester-based TPUs, ground polyether-based TPUs, or any blend thereof.

[0051] Cellular foams are typically processed by mixing liquid ingredients in a mold under low pressure in the presence of a blowing agent to produce a foamed molded article. The blowing agent can be a physical or chemical blowing agent.

[0052] The term "physical blowing agent" refers to a blowing agent that does not chemically react with the isocyanate component and / or the isocyanate-reactive component. The physical blowing agent may be a gas or a liquid. A liquid physical blowing agent typically evaporates to a gas when heated and returns to a liquid when cooled. In certain embodiments, the physical blowing agent may be a gas trapped within a polyurethane elastomer shell, where the gas expands with heat, causing the shell to grow. In certain embodiments, the physical blowing agent may be introduced via a masterbatch containing both the physical blowing agent and a polymer matrix composition such as ethylene vinyl acetate (EVA), or simply mixed with the remaining ingredients used to form the polyurethane foam.

[0053] In certain embodiments, liquid physical blowing agents evaporate to a gas when heated and revert to a liquid when cooled, hi certain embodiments, the liquid physical blowing agent is a liquefied gas, such as liquefied carbon dioxide or liquid nitrogen.

[0054] The term "chemical blowing agent" refers to a blowing agent that chemically reacts with an isocyanate or other component to release a blowing gas. One specific, non-limiting example of a chemical blowing agent is water. Other non-limiting examples of chemical blowing agents include citric acid or bicarbonate, which can also produce carbon dioxide.

[0055] The blowing agent is typically present in the isocyanate-reactive component for forming the polyurethane foam in an amount of from about 0.5 to about 20 parts by weight, based on 100 parts by weight of the total hydroxyl-functional polymer present in the isocyanate-reactive component used to form the polyurethane foam.

[0056] Also, as mentioned above, the isocyanate-functional polymer component of the present disclosure includes an isocyanate component having an isocyanate functional group as a reactive component that reacts with the isocyanate-reactive component. Suitable isocyanates for use in the isocyanate component include, but are not limited to, the isocyanates contained in the preformed polyurethane moldings described above (and other isocyanates not specifically described above), including aromatic or aliphatic isocyanate group-containing compounds (i.e., aromatic or aliphatic isocyanates), such as methylene diphenyl diisocyanate (MDI), toluene diisocyanate (TDI), polymethylene polyphenyl isocyanate (PMDI), hexamethylene diisocyanate (HDI), uretonimine polymers, isocyanate-terminated prepolymers, and any combination thereof.

[0057] The isocyanate component for use in forming the isocyanate-functional polymer component typically has an average functionality of about 1.5 to about 3.0, more typically about 2.0 to about 2.8, and even more typically about 2.7. The isocyanate component also typically has an NCO content that varies from a few percent to about 50% by weight, depending on the isocyanate component. For aliphatic isocyanates, the NCO content may range from about 18 to 30% by weight. For aromatic isocyanates, the NCO content may range from 25 to 50% by weight. For isocyanate prepolymers, the range may vary from 1 to 47% by weight, more typically from 1 to 29% by weight. For hexamethylene diisocyanate (HDI), the isocyanate component typically has an NCO content of about 20 to about 23.5% by weight. For methylene diphenyl diisocyanate (MDI), the isocyanate component typically has an NCO content of about 29 to about 34% by weight. In the case of toluene diisocyanate (TDI), the isocyanate component typically has an NCO content of about 45 to about 50 weight percent. Isocyanate-terminated prepolymers, when included in or otherwise present in the isocyanate component, are generally the reaction product of an isocyanate component (such as those described above) and an active hydrogen-containing species, and may be formed by a variety of methods understood by those skilled in the art or may be obtained commercially from manufacturers, suppliers, and the like. The active hydrogen-containing species may alternatively be referred to as an isocyanate-reactive component having a reactive group (i.e., a compound or composition having an active hydrogen atom) reactive with the isocyanate functionality of the isocyanate component.

[0058] In certain embodiments, the isocyanate component of the isocyanate-terminated prepolymer is selected from the group of methylene diphenyl diisocyanate (sometimes also referred to as diphenylmethane diisocyanate, MDI, or monomeric MDI), polymethylene polyphenyl diisocyanate (sometimes also referred to as polymeric diphenylmethane diisocyanate, polymeric MDI or PMDI), and combinations thereof. MDI exists in three isomers (2,2'-MDI, 2,4'-MDI, and 4,4'-MDI), although the 4,4' isomer (sometimes referred to as pure MDI) is the most widely used. For purposes of this disclosure, the term "MDI" refers to all three isomers unless otherwise specified. In certain embodiments, the second isocyanate-terminated prepolymer comprises a blend of PMDI and a quasi-prepolymer of 4,4'-methyldiphenyl diisocyanate.

[0059] The isocyanate-reactive component used to form the isocyanate-terminated prepolymer is preferably a polymer that contains one or more hydroxyl groups (OH functional groups), or more commonly referred to as a hydroxyl-functional polymer. The isocyanate component is a polymer that contains one or more isocyanate groups (NCO groups) that react with hydroxyl groups to form carbamate (i.e., urethane) linkages.

[0060] In certain embodiments, the hydroxyl functional polymer is a hydroxyl functional polyether (i.e., a polymer containing hydroxyl functional polyether groups), and in other embodiments, the hydroxyl functional polymer is a hydroxyl functional polyester (i.e., a polymer containing hydroxyl functional polyester groups). In yet other embodiments, the isocyanate-reactive component hydroxyl functional polymer can be a mixture of a hydroxyl functional polyether and a hydroxyl functional polyester.

[0061] The hydroxyl functional polyethers used as one of the reactants in forming the isocyanate-terminated prepolymers are polyether polymers containing one or more hydroxyl functional groups, typically at least two OH functional groups. Thus, hydroxyl functional polyethers are polyether polymers having one OH functional group (i.e., polyether monol), polyether polymers having two OH functional groups (i.e., polyether diol), polyether polymers having three OH functional groups (i.e., polyether triol), polyether polymers having four OH functional groups (i.e., polyether tetrol), polyether group-containing polymers having more than four OH functional groups, and combinations thereof. The hydroxyl functionality of these hydroxyl functional polyethers is typically expressed in terms of the average functionality of all of the respective polymer chains present in the collective hydroxyl functional polyether blend. Hydroxyl functional polyethers having an average of two or more OH functional groups per molecule are sometimes referred to as polyether polyols, and are typically formed as polymeric reaction products of organic oxides and initiator compounds containing two or more active hydrogen atoms. The active hydrogen compound initiates ring opening and oxide addition in the presence of a base catalyst. This is continued until the desired molecular weight is obtained. If the initiator has two active hydrogens, a diol results. If a trifunctional initiator such as glycerin is used, the chain grows in three directions by oxide addition, resulting in a triol.

[0062] The hydroxyl functional polyether can be any type of hydroxyl functional polyether known in the art. The hydroxyl functional polyether can be non-ethoxylated or ethoxylated. In addition, the hydroxyl functional polyether can be a short-chain low molecular weight hydroxyl functional polyether having one or more OH functional groups. Particularly suitable hydroxyl functional polyethers for use in polyurethanes include, but are not limited to, the products obtained by polymerization of cyclic oxides, such as ethylene oxide (EO), propylene oxide (PO), butylene oxide (BO) or tetrahydrofuran, in the presence of an initiator compound having one or more active hydrogen atoms. Suitable initiator compounds containing multiple active hydrogen atoms used to obtain hydroxyl-functional polyethers include water, butanediol, ethylene glycol, propylene glycol (PG), diethylene glycol, triethylene glycol, dipropylene glycol, ethanolamine, diethanolamine, triethanolamine, toluenediamine, diethyltoluenediamine, phenyldiamine, diphenylmethanediamine, ethylenediamine, cyclohexanediamine, cyclohexanedimethanol, resorcinol, bisphenol A, glycerol, trimethylolpropane, 1,2,6-hexanetriol, pentaerythritol, and combinations thereof.

[0063] Other suitable hydroxyl-functional polyethers include polyether diols and triols, such as polyoxypropylene diols and triols, poly(oxyethyleneoxypropylene) diols and triols, obtained by simultaneous or sequential addition of ethylene and propylene oxide to a difunctional or trifunctional initiator. Copolymers having an oxyethylene content of about 5 to about 90% by weight based on the weight of the polyether polyol component (the polyether polyols may be block, random / block or random copolymers) can also be used. Still other suitable hydroxyl-functional polyethers include polytetramethylene ether glycols obtained by polymerization of tetrahydrofuran.

[0064] Particularly suitable for use are one or more hydroxyl-functional polyethers based on a completely heteric (or random) EO (ethylene oxide), PO (propylene oxide) structure, or those with heteric but uniform blocks of EO and PO (e.g., blocks containing EO and blocks containing PO). As yet another suitable example, the hydroxyl-functional polyether can have heteric and uniform blocks of EO and PO, e.g., blocks containing all EO or PO, and blocks containing random EO and PO. Furthermore, in a particular example, the hydroxyl-functional polyether may be a heteric or random copolymer of EO and PO, end-capped with either EO or PO. One particularly suitable hydroxyl-functional polyether includes a polyether triol with ethylene oxide end groups.

[0065] Suitable non-limiting commercially available hydroxyl functional polyether or polyether diols having an average of two OH functional groups per molecule for use in forming the isocyanate-terminated prepolymers of the present disclosure are based on the propoxylation and / or ethoxylation of diethylene glycol, dipropylene glycol, ethylene glycol, or propylene glycol, and include Pluracol® P410R, 1010, 2010, 1062, and 1044, respectively, commercially available from BASF Corporation of Florham Park, NJ. In particular, Pluracol® P410R, 1010, 2010, and 1044 are PO-containing hydroxyl functional polyether diols, while Pluracol® 1062 is an EO end-capped PO-containing hydroxyl functional polyether diol.

[0066] Suitable non-limiting commercially available hydroxyl-functional polyether or polyethers having an average of three OH functional groups per molecule, sometimes referred to as polyether triols, for use in forming the isocyanate-terminated prepolymers of the present disclosure are based on the propoxylation and / or ethoxylation of glycerin or trimethylolpropane, and include Pluracol® GP430, GP730, 4156, 2090, and 816, each available from BASF Corporation of Florham Park, NJ. In particular, Pluracol® GP430 and GP730 are PO-containing hydroxyl-functional polyether triols, and Pluracol® 2090 and 816 are EO-endcapped PO-containing hydroxyl-functional polyether triols, while Pluracol® 4156 is a pure heteric hydroxyl-functional polyether triol.

[0067] Suitable non-limiting commercially available hydroxyl functional polyether(s) having an average of four OH functionalities per molecule, sometimes referred to as polyether tetrols, toluene diamine, ethylene diamine, and pentaerythritol, for use in forming the isocyanate-terminated prepolymers of the present disclosure include Pluracol® 735, 736, and PEP 500 and Quadrol, each available from BASF Corporation of Florham Park, NJ. In particular, Pluracol® 735 and 736 are PO-based, toluene diamine-initiated, hydroxyl functional polyether polyols, Pluracol® PEP 500 is a pentaerythritol-initiated heteric, and Quadrol is a PO-based, ethylene diamine-initiated, hydroxyl functional polyether polyol. One suitable non-limiting commercially available higher hydroxyl-functional polyether for use in forming the isocyanate-terminated prepolymers of the present disclosure based on sucrose, sorbitol or combinations thereof, alone or in combination with other initiators, is Pluracol® SG360 (based on sucrose and glycerin), commercially available from BASF Corporation, Florham Park, N.J. In some of these embodiments, the one or more hydroxyl-functional polyethers for use in forming the isocyanate-terminated prepolymers of the present disclosure have a weight average molecular weight (Mw) in the range of 60 to 10,000, e.g., 180 to 6,500 g / mol, as measured by gel permeation chromatography (GPC) or nuclear magnetic resonance (NMR) previously calibrated using a calibration curve based on monodisperse polystyrene standards.

[0068] In certain aspects, a combination of two or more hydroxyl functional polyethers may be used to form the isocyanate-terminated prepolymer, each of the two or more hydroxyl functional polyethers having the same or different weight average molecular weights in the range of 60 to 10,000, e.g., 180 to 6,500 g / mol as described above. Thus, for example, the hydroxyl functional polyethers used may include a first hydroxyl functional polyether having a weight average molecular weight in the range of 60 to 10,000, e.g., 180 to 6,500 g / mol, and a second hydroxyl functional polyether different from the first hydroxyl functional polyether, also having a weight average molecular weight in the range of 60 to 10,000, e.g., 180 to 6,500 g / mol. Representative examples of two or more hydroxyl functional polyethers include those described in the paragraph above. In still further embodiments, in addition to the hydroxyl functional polyether, the isocyanate-reactive component used to form the isocyanate-terminated prepolymer further includes a styrene-acrylonitrile graft polyol.

[0069] In certain embodiments, in addition to or instead of the hydroxyl-functional polyether, the isocyanate-reactive component used in forming the isocyanate-terminated prepolymer may be in the form of another hydroxyl-functional polymer, including, but not limited to, hydroxyl-functional polyesters and hydroxyl-functional acrylics.

[0070] Hydroxyl-functional polyesters suitable for use in forming isocyanate-terminated prepolymers include, for example, polyester polymers that contain one or more hydroxyl functional groups, typically at least two OH functional groups.Hydroxyl-functional polyesters are therefore polyester polymers with one OH functional group (i.e., polyester monol), polyester polymers with two OH functional groups (i.e., polyester diol), polyester polymers with three OH functional groups (i.e., polyester triol), polyester polymers with four OH functional groups (i.e., polyester tetrol), polyether polymers with more than four OH functional groups, and combinations thereof.Hydroxyl-functional polyesters with an average of two or more OH functional groups per molecule are sometimes referred to as polyester polyols.

[0071] Suitable hydroxyl functional polyesters include, but are not limited to, aromatic group-containing hydroxyl functional polyesters, hydroxyl-terminated reaction products of polyhydric alcohols, such as ethylene glycol, propylene glycol, diethylene glycol, 1,4 butanediol, neopentyl glycol, 1,6-hexanediol, cyclohexanedimethanol, glycerol, trimethylolpropane, pentaerythritol or polyether polyols, or mixtures of such polyhydric alcohols, and polycarboxylic acids, especially dicarboxylic acids or their ester-forming derivatives, such as succinic acid, glutaric acid and adipic acid, or their dimethyl esters sebacic acid, phthalic anhydride, tetrachlorophthalic anhydride or dimethyl terephthalate, or mixtures thereof. Polyester polyols obtained by polymerization of lactones, such as caprolactone, in combination with polyols, or polyester polyols obtained by polymerization of hydroxycarboxylic acids, such as hydroxycaproic acid, may also be used.

[0072] Polyesteramide polyols suitable for use in forming the isocyanate-terminated prepolymers can be obtained by including amino alcohols such as ethanolamine in the polyesterification mixture. Suitable polythioether polyols include products obtained by condensing thiodiglycol alone or with other glycols, alkylene oxides, dicarboxylic acids, formaldehyde, amino alcohols or amino carboxylic acids. Suitable polycarbonate polyols include products obtained by reacting diols such as 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol or tetraethylene glycol with diaryl carbonates such as diphenyl carbonate or phosgene. Suitable polyacetal polyols include those prepared by reacting glycols such as diethylene glycol, triethylene glycol or hexanediol with formaldehyde. Other suitable polyacetal polyols can also be prepared by polymerizing cyclic acetals. Suitable polyolefin polyols include hydroxy-terminated butadiene homopolymers and copolymers, and suitable polysiloxane polyols include polydimethylsiloxane diols and triols.

[0073] Additionally, low molecular weight hydroxyl functional compounds may also be utilized in forming the isocyanate-terminated prepolymer, such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butanediol, glycerol, trimethylolpropane, triethanolamine, pentaerythritol, sorbitol, and combinations thereof. The isocyanate-reactive component used in forming the isocyanate-terminated prepolymer may also include one or more catalysts. A catalyst is typically present in the isocyanate-reactive component to catalyze the reaction between the isocyanate component and the isocyanate-reactive component.

[0074] The isocyanate-reactive component for use in forming the isocyanate-terminated prepolymer may also include various additional additives. Suitable additives include, but are not limited to, defoamers, processing additives, plasticizers, chain terminators, surfactants, flame retardants, antioxidants, water scavengers, fumed silica, dyes or pigments, UV stabilizers, fillers, thixotropic agents, silicones, amines, transition metals, and combinations thereof. The additives can be included in any amount desired by one of ordinary skill in the art. For example, pigment additives allow the polyurethane elastomer composition to be visually evaluated for thickness and integrity, which can provide various marketing advantages. Hydroxyl-functional acrylics suitable for use in forming the isocyanate-terminated prepolymer are obtained by free radical polymerization of acrylate and methacrylate esters and styrenes (e.g., ethyl acrylate (EA) or butyl acrylate (BA), acrylic acid (AA), methyl methacrylate (MMA), or styrene (ST)). Hydroxyl functionality is introduced by adding an ethylenically unsaturated monomer having at least one free hydroxyl group, typically a hydroxy-functional acrylate (HFA), such as 2-hydroxyethyl acrylate (HEA) or 4-hydroxybutyl acrylate (HBA), to the monomer blend. One exemplary 100% solids acrylic-modified polyether polyol is Joncryl 569, available from BASF Corporation, Florham Park, New Jersey, with a hydroxyl number of 140 mg KOH / g.

[0075] Specific examples of suitable isocyanate-terminated prepolymers for purposes of the present disclosure are commercially available from BASF Corporation, Florham Park, NJ under the trade name Lupranate®, such as Lupranate® MP 102. It will be understood that the system can include a combination of two or more of the foregoing isocyanate-terminated prepolymers.

[0076] Exemplary diisocyanates that may be used in forming the polycarbodiimide include, but are not limited to: MDI (any of the three isomers, 2,2'-MDI, 2,4'-MDI, and 4,4'MDI); m-phenylene diisocyanate; 2,4-toluene diisocyanate; 2,6-toluene diisocyanate; hexamethylene diisocyanate; 1,4-phenylene diisocyanate; tetramethylene diisocyanate; cyclohexane diisocyanate; Xanthane-1,4-diisocyanate;Hexahydrotoluene diisocyanate;Methylene diisocyanate;2,6-Diisopropylphenyl isocyanate;m-Xylylene diisocyanate;Dodecyl isocyanate;3,3'-Dichloro-4,4'-diisocyanato-1,1'-biphenyl;1,6-Diisocyanato-2,2,4-trimethylhexane;3,3'-Dimethoxy-4,4'-biphenylene diisocyanate;2,2-Diisocyanatop 1,3-Diisocyanatopropane;1,4-Diisocyanatobutane;1,5-Diisocyanatopentane;1,6-Diisocyanatohexane;2,3-Diisocyanatotoluene;2,4-Diisocyanatotoluene;2,5-Diisocyanatotoluene;2,6-Diisocyanatotoluene;Isophorone diisocyanate;Hydrogenated methylene bis(phenylisocyanate);Naphthalene-1,5 diisocyanate;1-Methoxyphenyl-2,4-diisocyanate 4,4',4'' triphenylmethane triisocyanate; toluene-2,4,6-triisocyanate; 4,4' dimethyldiphenylmethane-2,2',5,5'-tetraisocyanate; polymethylene polyphenylene polyisocyanate; or a mixture of any two or more thereof. In a preferred embodiment, the diisocyanate is 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, or a mixture of 2,4 and 2,6-toluene diisocyanate.

[0077] In certain embodiments, the isocyanate component for forming the polycarbodiimide comprises MDI (any of the three isomers: 2,2'-MDI, 2,4'-MDI, and 4,4'-MDI). Alternatively, the isocyanate component may comprise a blend of two or all three of these three MDI isomers, i.e., the isocyanate component may comprise at least two of 2,2'-MDI, 2,4'-MDI, and 4,4'-MDI.

[0078] In certain other embodiments, the isocyanate component for forming the polycarbodiimide comprises toluene diisocyanate (TDI). The isocyanate component may comprise either isomer of toluene diisocyanate (TDI), i.e., the isocyanate component may comprise 2,4-toluene diisocyanate (2,4-TDI) or 2,6-toluene diisocyanate (2,6TDI). Alternatively, the isocyanate component may comprise a blend of these isomers, i.e., the isocyanate component may comprise both 2,4-toluene diisocyanate (2,4-TDI) and 2,6-toluene diisocyanate (2,6-TDI). One specific example of a commercially available isocyanate component suitable for purposes of the present disclosure is Lupranate® T-80, available from BASF Corporation, Florham Park, New Jersey. In particular, Lupranate® T-80 comprises a blend of 2,4-toluene diisocyanate (2,4-TDI) and 2,6-toluene diisocyanate (2,6-TDI). In certain embodiments, the isocyanate component consists essentially of, or consists of, TDI. Generally, the isocyanate component comprises TDI in an amount greater than 95% by weight, alternatively greater than 96% by weight, alternatively greater than 97% by weight, alternatively greater than 98% by weight, or alternatively greater than 99% by weight, based on the total weight of isocyanates present in the isocyanate component.

[0079] In one embodiment, the present invention provides a polyurethane composition comprising toluene-2,4-diisocyanate and toluene-2,6-diisocyanate.

[0080] Polyurethane (PUR or PU) refers to a class of polymers composed of organic units joined by carbamate (urethane) bonds. In contrast to other common polymers such as polyethylene and polystyrene, polyurethanes are produced from a wide range of starting materials (monomers) and are therefore a class of polymer rather than a distinct chemical compound. This chemical diversity gives polyurethanes very different physical properties, leading to an equally wide variety of different applications, including rigid and flexible foams, varnishes and coatings, adhesives, electrical potting compounds, and fibers such as spandex and PUL. Of these, foams are the largest single application.

[0081] Polyurethane polymers are traditionally and most commonly formed by reacting a diisocyanate or triisocyanate with a polyol. Polyurethanes are classified as alternating copolymers because they contain two types of monomers that polymerize one after the other. Both the isocyanates and polyols used to make polyurethanes contain, on average, two or more functional groups per molecule. The compositions described herein include toluene diisocyanate (TDI) as the diisocyanate of the PU composition.

[0082] Toluene diisocyanate, or TDI, is an organic compound with the formula CH3C6H3(NCO)2. Two of the six possible isomers, 2,4-TDI (CAS: 584-84-9) and 2,6-TDI (CAS: 91-08-7), are commercially important. While 2,4-TDI is manufactured in pure form, TDI is often commercially available as an 80 / 20 and 65 / 35 mixture of the 2,4 and 2,6 isomers, respectively. The isocyanate functional groups in TDI react with hydroxyl groups to form carbamate (urethane) bonds. The two isocyanate groups in TDI react at different rates: the 4-position is about four times more reactive than the 2-position. 2,6-TDI is a symmetric molecule, so it has two isocyanate groups of similar reactivity, as does the 2-position in 2,4-TDI. However, because both isocyanate groups are attached to the same aromatic ring, reaction of one isocyanate group causes a change in the reactivity of the second isocyanate group.

[0083] The isocyanate component of the compositions described herein includes a blend of 2,4-toluene diisocyanate (2,4-TDI) and 2,6-toluene diisocyanate (2,6TDI) isomers.

[0084] In one embodiment, the composition includes about 50% to 80% toluene-2,4-diisocyanate, for example, the composition includes about 50, 55, 60, 65, 70, 75, or 80% toluene-2,4-diisocyanate.

[0085] In another embodiment, the composition includes about 10% to 20% toluene-2,6-diisocyanate, for example, the composition includes about 10, 15, or 20% toluene-2,6-diisocyanate.

[0086] In some embodiments, the composition includes about 50%-75% toluene-2,4-diisocyanate and about 10%-15% toluene-2,6-diisocyanate; about 50%-75% toluene-2,4-diisocyanate and about 15%-20% toluene-2,6-diisocyanate; or about 60%-80% toluene-2,4-diisocyanate and about 10%-20% toluene-2,6-diisocyanate.

[0087] In another embodiment, the compositions described herein are for use in making a polyurethane prepolymer.

[0088] As used herein, the term "prepolymer" or "polyurethane prepolymer" refers to a polymer used in preparation for the production of polyurethane molded articles. As described in more detail below, the compositions described herein, including blends of 2,4-toluene diisocyanate (2,4-TDI) and 2,6-toluene diisocyanate (2,6TDI) isomers, are used to convert polyurethane molded articles, such as foams, to polyurethane prepolymers that can be used to produce secondary polyurethane molded articles. Prepolymers also include TDI mixed with polyols.

[0089] In various embodiments, the toluene diisocyanate compositions described herein are liquid compositions used to convert polyurethane articles to prepolymers. In many embodiments, the polyurethane articles include solid polyurethane articles and the resulting polyurethane prepolymers are liquid polyurethane prepolymers.

[0090] In one embodiment, the prepolymers are used in the manufacture of industrial chemicals and / or industrial polymers.

[0091] As used herein, the terms "industrial chemicals" and "industrial polymers" are meant to refer to any product that can be produced using the prepolymers obtained using the compositions described herein. Non-limiting examples of industrial chemicals and industrial polymers include flexible foams, primarily used in bedding and furniture, carpet underlay, and polyurethanes for the manufacture of packaging materials, coatings, sealants, adhesives, and elastomers.

[0092] In one embodiment, the present invention provides a method for producing a polyurethane prepolymer, comprising the steps of: The present invention provides a method for producing a polyurethane prepolymer, the method comprising the steps of: a) processing and / or densifying a preformed polyurethane article; b) preheating a toluene diisocyanate composition at a temperature in the range of about 130 to 165° C.; and c) contacting the processed and / or densified preformed polyurethane article with the toluene diisocyanate composition, thereby producing a polyurethane prepolymer.

[0093] As used herein, the terms "processing" and "densification" of an article are meant to refer to any process applied to an article that results in an increase in the density of the article, a decrease in the volume of the article, or a combination thereof. Examples of methods for increasing article density include, but are not limited to, grinding, consolidating, compressing, milling, crushing, squeezing, etc.

[0094] The methods described herein rely on contacting a preformed polyurethane article with a TDI composition. This chemical conversion is optimized by preheating the TDI composition before adding the polyurethane article. Optimization means that the chemical reaction is faster and / or more efficient. In some embodiments, the preheating is performed at a temperature in the range of about 130°C to 165°C. For example, the preheating temperature is about 125, 130, 135, 140, 145, 150, 155, 160, 165, or 170°C. In other examples, the preheat temperature is in the range of about 130-135°C, 135-140°C, 140-145°C, 145-150°C, 150-155°C, 155-160°C, 160-165°C, 130-140°C, 140-150°C, 150-160°C, 135-145°C, 145-155°C, 155-165°C, 130-145°C, 145-160°C, 135-150°C, 150-165°C, 130-150°C, 135-155°C, 140-160°C, 145-165°C, 130-155°C, 135-160°C, 140-165°C, 130-160°C, or 135-165°C.

[0095] In various embodiments, the preheat temperature ranges from about 160° C. to 165° C. For example, preheat temperatures include 159° C., 160° C., 161° C., 162° C., 163° C., 164° C., 165° C., and 166° C.

[0096] In another aspect, increasing the preheat temperature decreases the processing time.

[0097] The processing and preheating steps are independent steps and can be performed in any order, simultaneously, or one before the other, provided that the contacting step includes contacting the processed / densified article with a preheated composition.

[0098] In some embodiments, the processing and / or densification steps occur before, after, or simultaneously with the preheating step.

[0099] In one embodiment, the polyurethane composition comprises about 50%-75% toluene-2,4-diisocyanate and about 10%-15% toluene-2,6-diisocyanate. In another embodiment, the polyurethane composition comprises about 50%-75% toluene-2,4-diisocyanate and about 15%-20% toluene-2,6-diisocyanate. In a further embodiment, the polyurethane composition comprises about 60%-80% toluene-2,4-diisocyanate and about 10%-20% toluene-2,6-diisocyanate.

[0100] In one embodiment, the preformed polyurethane article is a polyurethane foam.

[0101] As used herein, the term "polyurethane foam" is meant to include flexible and rigid polyurethane foams. As used herein, the term "flexible polyurethane foam" refers to a specific type of polyurethane foam and is contrasted with "rigid polyurethane foam." Flexible polyurethane foams are generally porous and have open cells, whereas rigid polyurethane foams are generally non-porous, have closed cells, and do not have rubber-like properties. Specifically, flexible polyurethane foams are soft cellular products that do not burst when a 200 mm x 25 mm x 25 mm specimen is bent at a uniform rate of once per 5 seconds around a 25 mm diameter mandrel at a temperature of 18-29°C, as defined by ASTM D3574-03.

[0102] Flexible polyurethane foams are typically produced from hydroxyl-functional polymers having a weight average molecular weight of about 1,000 to about 10,000 g / mol and a hydroxyl value of about 10 to about 200 mg KOH / g. In contrast, rigid polyurethane foams are typically produced from hydroxyl-functional polymers having a weight average molecular weight of about 250 to about 700 g / mol and a hydroxyl value of about 300 to about 700 mg KOH / g. In addition, flexible polyurethane foams generally contain more urethane bonds compared to rigid polyurethane foams, while rigid polyurethane foams may contain more isocyanurate bonds compared to flexible polyurethane foams. In addition, flexible polyurethane foams are typically produced from initiators with low functionality (f), i.e., f<4, such as dipropylene glycol (f=2) or glycerin (f=3). In comparison, rigid polyurethane foams are typically produced from hydroxyl functional polymers with high functionality initiators, i.e., f>4, such as Mannich bases (f=4), toluene diamine (f=4), sorbitol (f=6) or sucrose (f=8). Furthermore, as known in the art, flexible polyurethane foams are typically produced from glycerin-based hydroxyl functional polymers, whereas rigid polyurethane foams are typically produced from multifunctional hydroxyl functional polymers that generate a three-dimensional crosslinked cell structure, thereby increasing the rigidity of the rigid polyurethane foam. Finally, although both flexible and rigid polyurethane foams contain cell structures, flexible polyurethane foams typically contain more open cell walls that allow air to pass through the flexible polyurethane foam when force is applied, compared to rigid polyurethane foams. Thus, flexible polyurethane foams typically recover their shape after compression. In contrast, rigid polyurethane foams typically contain many more closed cell walls, restricting the flow of air through the rigid polyurethane foam when force is applied.

[0103] In one embodiment, the polyurethane foam is selected from the group consisting of a microcellular foam, a semi-rigid foam, a molded foam, and any combination thereof. In some embodiments, the foam comprises a polyol having a molecular weight in the range of about 1000 to 3600 Da.

[0104] In other aspects, the step of processing and / or densifying the foam includes crushing the foam to obtain chopped foam.

[0105] Foams are low density materials with a large volume relative to their density. In order to optimize the interface between the polyurethane composition and the foam without the need for excessive amounts of polyurethane composition, the methods described herein provide for processing and / or densifying the foam before contacting it with the polyurethane composition (e.g., a preheated polyurethane composition). As used herein, the term "processing" of a foam is meant to refer to any process applied to the foam that results in an increase in the density of the foam, a decrease in the volume of the foam, or a combination thereof. Examples of methods for increasing the density of a foam include, but are not limited to, grinding, compacting, compressing, milling, crushing, squeezing, and the like.

[0106] In various embodiments, the processing and / or densifying step comprises using a grinder, processor, shredder, granulator, crusher, compactor, or pulverizer.

[0107] In another embodiment, the chopped foam pieces have a size ranging from about 500 μm to 5 mm.

[0108] Increasing the density of the foam or decreasing the volume of the foam (e.g., by grinding) involves generating foam fragments of a size smaller than the initial foam pieces. The methods of making polyurethane prepolymers described herein rely on contacting a polyurethane composition with foam fragments such that the surface of the foam in contact with the composition is optimized. The term "foam fragments" as used herein is meant to include fragments having a size ranging from about 500 μm to 5 mm. For example, the foam fragments are about 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, or larger.

[0109] In some embodiments, the chopped foam pieces have a size of about 1 mm.

[0110] In one embodiment, the manufacture is a continuous process.

[0111] The term "continuous" as used herein is meant to refer to a non-batch process. The methods described herein allow for the continuous (i.e., uninterrupted) production of polyurethane prepolymers. Generally, a preformed polyurethane molded article is first produced using a polyurethane prepolymer, and the methods described herein can allow the preformed solid polyurethane molded article (i.e., a foam) to be converted into a liquid polyurethane prepolymer having the same or substantially the same properties as the polyurethane prepolymer used to produce the foam. Thus, the polyurethane prepolymer produced by the methods described herein can be used to produce new polyurethane molded articles.

[0112] The present disclosure relies on the discovery of a means to optimize such a process so that it can be performed continuously without the need to interrupt to refresh the material. As long as the polyurethane composition (and then the polyurethane composition / polyurethane article mixture) is maintained at the preheat temperature, foam fragments can be added to the composition to produce a polyurethane prepolymer from a preformed solid polyurethane article.

[0113] In another embodiment, the contacting includes contacting about 1-30% w / w of the polyurethane molded article with the TDI composition. In various embodiments, the contacting includes contacting about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, or 30% w / w of the polyurethane molded article with the TDI composition.

[0114] The methods described herein allow for a continuous process, i.e., the possibility of continuously adding polyurethane molded article fragments to the TDI composition to produce polyurethane prepolymer. To maintain the continuity of the process, the amount of polyurethane molded article should not exceed about 35% of the amount of polyurethane composition. Optimal reaction conditions that allow for the continuity of the reaction include foam:polyurethane composition weight / weight ratios in the range of about 1-30% w / w. For example, optimal reaction conditions include 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 35% w / w or more of polyurethane molded article.

[0115] In one embodiment, the method further comprises agitating the preformed polyurethane article and the heated polyurethane composition.

[0116] Agitation of the pieces of the preformed polyurethane article and the heated composition can be used to maintain optimal contact between the pieces of the article and the heated composition throughout the processing time.

[0117] In another embodiment, the temperature used to preheat the toluene diisocyanate composition (i.e., the preheat temperature) is maintained throughout the contacting step. In many embodiments, the contacting temperature (i.e., the temperature during the reaction that occurs between the processed and / or densified preformed polyurethane article and the toluene diisocyanate composition) ranges from about 130°C to 165°C. For example, the contact temperature is maintained at about 130-135°C, 135-140°C, 140-145°C, 145-150°C, 150-155°C, 155-160°C, 160-165°C, 130-140°C, 140-150°C, 150-160°C, 135-145°C, 145-155°C, 155-165°C, 130-145°C, 145-160°C, 135-150°C, 150-165°C, 130-150°C, 135-155°C, 140-160°C, 145-165°C, 130-155°C, 135-160°C, 140-165°C, 130-160°C, or 135-165°C.

[0118] In other examples, the contact temperature is about 125, 130, 135, 140, 145, 150, 155, 160, 165, or 170° C. In various embodiments, the contact temperature ranges from about 160 to 165° C. For example, contact temperatures include 159° C., 160° C., 161° C., 162° C., 163° C., 164° C., 165° C., and 166° C.

[0119] In one embodiment, the method further comprises the step of adding a catalyst after step (b).

[0120] In a further embodiment, the polyurethane prepolymers produced by the methods described herein are used in the production of industrial chemicals and / or industrial polymers.

[0121] The polyurethane prepolymers produced by the methods described herein are preferably in liquid form at room temperature and have a known isocyanate functional group content (NCO content) based on the total weight of the isocyanate components contained in the mixture.

[0122] In yet a further aspect, the method for forming the isocyanate-functional prepolymer may optionally include a step of filtering or otherwise removing insoluble particles or other materials that may remain in the isocyanate-functional prepolymer component after completion of the reaction (as evidenced by a reduction in NCO content). Although the insoluble particles or materials described above generally do not affect the subsequent use of the formed isocyanate-functional prepolymer component in forming a novel polyurethane molded article or a novel polyurethane foam molded article, it may be desirable to remove them to improve the aesthetic appearance of the novel polyurethane molded article or novel polyurethane foam molded article.

[0123] As noted above, the prepolymers described herein can be used to make industrial chemicals and / or industrial polymers, such as novel polyurethane molded articles, particularly novel polyurethane foam molded articles, formed by including the isocyanate-functional prepolymer component formed as described above as at least a portion of the isocyanate component.

[0124] The term "new" as used with respect to "new polyurethane molded article" and "new polyurethane foam molded article" refers to the reaction product formed in this disclosure and serves to distinguish it from the recycled polyurethane molded article described above.

[0125] The novel polyurethane molded articles and related novel polyurethane foam molded articles of the present disclosure are formed as a reaction product of an isocyanate-functional polymer component according to any of the embodiments described above; a second isocyanate component having an isocyanate functionality; and an isocyanate-reactive component having a hydroxyl functionality reactive with the isocyanate functionality of the isocyanate-functional polymer component and the second isocyanate component.

[0126] The method for forming the novel polyurethane molded article of the present disclosure includes forming an isocyanate-functional prepolymer component as described above; providing a second isocyanate component (i.e., the isocyanate component used in forming the above-mentioned isocyanate-functional polymer component) that is the same or different from the first isocyanate component; providing an isocyanate-reactive component having a hydroxyl functional group reactive with the isocyanate functional group of the isocyanate functional polymer component and the second isocyanate component; forming a second mixture by mixing the provided second isocyanate component and the provided second isocyanate functional polymer component and the isocyanate-reactive component; and reacting the isocyanate functional group of the isocyanate functional polymer component and the second isocyanate component with the hydroxyl functional group of the isocyanate-reactive component to form a polyurethane elastomer. The method for forming the novel polyurethane foam molded article includes forming the reaction product in the presence of a blowing agent, so that the resulting structure of the novel polyurethane foam molded article is formed as a cellular structure with open cells formed therein.

[0127] Suitable isocyanates for use as the second isocyanate component are the same as those described above for use in forming the isocyanate-functional polymer component or were originally utilized in forming the recycled polyurethane molded article, including, but not limited to, aromatic or aliphatic isocyanate group-containing compounds (i.e., aromatic or aliphatic isocyanates), such as methylene diphenyl diisocyanate (MDI), toluene diisocyanate (TDI), polymethylene polyphenyl isocyanate (PMDI), hexamethylene diisocyanate (HDI), uretonimine polymers, isocyanate-terminated prepolymers, and any combination thereof. As above, the average functionality of the second isocyanate component is typically about 1.5 to about 3.0, more typically about 2.0 to about 2.8, and even more typically about 2.7. In certain embodiments, the second isocyanate component is of the same composition as the isocyanate component used to form the isocyanate-functional polymer component. In other embodiments, the composition of the second isocyanate component is different from the composition of the isocyanate component used to form the isocyanate-functional polymer component, but is selected from any of the isocyanate components described above. Similarly, the hydroxyl-functional isocyanate-reactive component used to form the novel polyurethane molded article or novel polyurethane foam molded article can be selected from the same hydroxyl-functional isocyanate-reactive components described above to form the isocyanate prepolymer. In these embodiments, the isocyanate-reactive component includes a hydroxyl functional group (OH) that can be reactive with the isocyanate functional groups present in the isocyanate-functional polymer component and in the second isocyanate component.

[0128] In certain embodiments, the ratio of isocyanate functionality of the isocyanate-functional polymer component and the second isocyanate component to hydroxyl functionality of the isocyanate-reactive component (ie, the NCO:OH ratio) ranges from 0.90:1 to 3.0:1.

[0129] For novel flexible polyurethane molded articles, such as novel flexible polyurethane foam molded articles, the NCO:OH ratio is in the range of 0.90:1 to 1.05:1. For novel rigid polyurethane molded articles, such as novel rigid polyurethane foam molded articles, the NCO:OH ratio is in the range of 1.05:1 to 3.0:1. For novel semi-rigid polyurethane molded articles, such as novel semi-rigid polyurethane foam molded articles, the NCO:OH ratio is generally about 1.05:1. In yet a further embodiment, the isocyanate-functional polymer component comprises 1 to 99 weight percent of the combined weight of the isocyanate-functional polymer component and the second isocyanate component.

[0130] In a further aspect, the novel polyurethane molded article or novel polyurethane foam molded article may include additional components selected from the group consisting of chain extenders, amines, catalysts, tin catalysts, crosslinking agents (i.e., curing agents), adhesion promoters, wetting agents, and any combination thereof.

[0131] The chain extenders used to form the novel polyurethane molded articles or novel polyurethane foam molded articles according to the present disclosure suitably include compounds having two or more active hydrogens and a molecular weight in the range of 60 g / mol to 400 g / mol, for example, 60 g / mol to 200 g / mol. Suitable chain extenders having two or more active hydrogens include, for example, diols and higher hydroxyl functional compounds or compositions, such as 1,4-butanediol, ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, 1,4-butylene glycol, butenediol, butynediol, xylylene glycol, amylene glycol, 1,5-pentylene glycol, methylpentanediol, 1,6-hexylene glycol, neopentyl glycol, trimethylolpropane, hydroquinone ether alkoxylates, resorcinol ether alkoxylates, glycerol, pentaerythritol, diglycerol, dextrose, 1,4-phenylene-bis(glycerol), glycerol, ... -hydroxyethyl ether, 1,3-phenylene-bis-hydroxyethyl ether, bis-(hydroxy-methyl-cyclohexane), hexanediol, thiodiglycol and 1,4:3,6 dianhydrohexitol, such as isomannide; isosorbide and isoidide; aliphatic polyamines such as ethylenediamine, hexamethylenediamine and isophoronediamine; aromatic polyamines such as methylene-bis(2-chloroaniline), methylenebis(dipropylaniline), diethyl-toluenediamine, trimethylene glycol di-p-aminobenzoate; and alkanolamines such as diethanolamine, triethanolamine, and diisopropanolamine.

[0132] In certain embodiments, the chain extender is a diol, such as one or more diols from the list above. When higher functionality polyols, such as triols, are included, they are typically introduced in low relative amounts in combination with the diols as described above to limit crosslinking and prevent the resulting novel polyurethane molded article or novel polyurethane foam molded article from becoming too brittle.

[0133] The isocyanate-reactive component used to form the new polyurethane molded article or the new polyurethane foam molded article may also include one or more amines. Any amine known in the art may be utilized, and may be described as a chain extender in some cases. Suitable amines that may be considered as chain extenders include diamines including ethylenediamine, propylenediamine, butylenediamine, hexa-methylenediamine, cyclohexanediamine, phenylenediamine, tolylenediamine, xylylenediamine, 3,3'-dichlorobenzidine, and 3,3'-dinitrobenzidine; alkanolamines such as ethanolamine, aminopropyl alcohol, 2,2-dimethylpropanolamine, 3-aminocyclohexyl alcohol, p-aminobenzyl alcohol; and combinations thereof. In further embodiments, the amine may be selected from MDA, TDA, ethylene-, propylene-butylene-, pentane-, hexane-, octane-, decane-, dodecane-, tetradecane-, hexa-decane-, octadecane diamines, hindered secondary amines such as Jeffamines-200, -400, -2000, -5000, Unilink 4200, Curene 442, Polacure 740, Ethacure 300, Lonzacure M-CDEA, Polyaspartics, 4,9 Dioxadodecan-l, 12 diamines, and combinations thereof.In other embodiments, the amine is selected from the group consisting of Lupragen® API-N-(3-aminopropyl)imidazole, Lupragen® DMI-1, 2-dimethylimidazole, Lupragen® DMI-1, 2-dimethylimidazole, Lupragen® N 100-N,N-dimethylcyclohexylamine, Lupragen® N 101-dimethylethanolamine, Lupragen® N 103-N,N-dimethylbenzylamine, Lupragen® N 104-N-ethylmorpholine, Lupragen® N 105-N-methylmorpholine, Lupragen® N 106-2,2'-dimorpholinodiethyl ether, Lupragen® N 107-dimethylaminoethoxyethanol, Lupragen® N 201-TEDA in DPG, Lupragen® N 202-TEDA in BDO, Lupragen® N 203-TEDA in MEG, Lupragen® N 204-N,N'-Dimethylpiperazine, Lupragen® N 205-Bis(2-dimethylaminoethyl)ether, Lupragen® N 206-Bis(2-dimethylaminoethyl)ether, Lupragen® N 301-Pentamethyldiethylene-triamine, Lupragen® N 301-Pentamethyldiethylenetriamine, Lupragen® N 400-Trimethylaminoethylethanolamine, Lupragen® N 500-Tetramethyl-1,6-hexanediamine, Lupragen® N 500-Tetramethyl-1,6-hexanediamine, Lupragen® N 600-S-triazine, Lupragen® N 700-1,8-diazabicyclo-5,4,0-undecene-7, Lupragen® NMI-N-methylimidazole, and combinations thereof. The isocyanate-reactive components used to form the novel polyurethane molded article or novel polyurethane foam molded article may also include one or more catalysts.A catalyst is typically present in the isocyanate-reactive component to catalyze the reaction between the isocyanate component (including the isocyanate-functional polymer component and the second isocyanate component) and the isocyanate-reactive component. That is, the isocyanate-reactive component typically includes a "polyurethane catalyst" that catalyzes the reaction between the isocyanate functional groups of the isocyanate-functional polymer component and the second isocyanate component and the hydroxyl functional groups of the isocyanate-reactive groups, including the hydroxyl groups derived from the polydiene polyol.

[0134] It is understood that the catalyst is typically not consumed in the exothermic reaction between the isocyanate component (including the isocyanate-functional polymer component and the second isocyanate component) and the isocyanate-reactive component. More specifically, the catalyst is typically involved in the exothermic reaction, but is not consumed in the exothermic reaction.

[0135] The catalyst may include any suitable catalyst or mixture of catalysts known in the art, including many of the catalysts described above for the formation of isocyanate-terminated prepolymers. Examples of suitable catalysts include, but are not limited to, gelling catalysts, such as amine catalysts in dipropylene glycol; blowing catalysts, such as bis(dimethylaminoethyl)ether in dipropylene glycol; and metal catalysts, such as organotin compounds, organobismuth compounds, organolead compounds, and the like. The catalyst may be any of those known in the art. In one embodiment, the isocyanate catalyst is an amine catalyst. In another embodiment, the isocyanate catalyst is an organometallic catalyst.

[0136] The isocyanate catalyst may be or may include a tin catalyst. Suitable tin catalysts include, but are not limited to, tin(II) salts of organic carboxylic acids, such as tin(II) acetate, tin(II) octoate, tin(II) ethylhexanoate, and tin(II) laurate. In one embodiment, the isocyanate catalyst is or includes dibutyltin dilaurate, which is a dialkyltin(IV) salt of an organic carboxylic acid. Non-limiting examples of isocyanate catalysts are commercially available from Air Products and Chemicals, Inc., Allentown, Pennsylvania, under the trademark DABCO®. The isocyanate catalyst may also include other dialkyltin(IV) salts of organic carboxylic acids, such as dibutyltin diacetate, dibutyltin maleate, and dioctyltin diacetate.

[0137] Other suitable, but non-limiting, examples of isocyanate catalysts include iron(II) chloride; zinc chloride; lead octoate; tris(dialkylaminoalkyl)-s-hexahydrotriazines, such as tris(N,N-dimethylaminopropyl)-s-hexahydrotriazine; tetraalkyl ammonium hydroxides, such as tetramethylammonium hydroxide; alkali metal hydroxides, such as sodium hydroxide and potassium hydroxide; alkali metal alkoxides, such as sodium methoxide and potassium isopropoxide; and alkali metal salts of long chain fatty acids having 10-20 carbon atoms and / or lateral OH groups.

[0138] Further examples of suitable, but non-limiting, isocyanate catalysts include N,N,N-dimethylaminopropylhexahydrotriazine, potassium, potassium acetate, N,N,N-trimethylisopropylamine / formate, and combinations thereof. Specific examples of suitable trimerization catalysts are commercially available from Air Products and Chemicals, Inc. under the POLYCAT® trademark.

[0139] Still further examples of other suitable, but non-limiting, isocyanate catalysts include dimethylaminoethanol, dimethylaminoethoxyethanol, triethylamine, N,N,N',N'-tetramethylethylenediamine, N,N-dimethylaminopropylamine, N,N,N',N',N''-pentamethyldipropylenetriamine, tris(dimethylaminopropyl)amine, N,N-dimethylpiperazine, tetramethylimino-bis(propylamine), dimethylbenzylamine, trimethylamine, triethanolamine, N,N-diethylethanolamine, N-methylpyrrolidone, N-methylmorpholine, N-ethylmorpholine, bis(2-dimethylamino-ethyl)ether, N,N-dimethylcyclohexylamine (DMCHA), N,N,N',N',N''-pentamethyldiethylenetriamine, 1,2-dimethylimidazole, 3-(dimethylamino)propylimidazole, and combinations thereof. In various embodiments, the isocyanate catalyst is commercially available from Air Products and Chemicals, Inc. under the trademark POLYCAT®. The isocyanate catalyst may include any combination of one or more of the aforementioned catalysts. In still other embodiments, the catalyst is selected from DABCO TMR, DABCO TMR-2, DABCO HE, DABCO 8154, PC CAT DBU TA 1, PC CAT Ql, Polycat SA-1, Polycat SA-102, salt forms, and / or combinations thereof.

[0140] In other embodiments, the catalyst is selected from the group consisting of dibutyltin dilaurate, dibutyltin oxide (e.g., as a liquid solution in C8-C10 phthalates), dibutyltin dilauryl mercaptide, dibutyltin bis(2-ethylhexylthioglycolate), dimethyltin dilauryl mercaptide, dimethyltin dineodecanoate, dimethyltin dioleate, dimethyltin bis(2-ethylhexylthioglycolate), dioctyltin dilaurate, dibutyltin bis(2-ethylhexanoate), stannous octanoate, stannous oleate, dibutyltin dimaleate, dioctyltin dimaleate, dibutyitin maleate, dibutyltin mercaptopropionate, dibutyltin bis(isodithioglycolate), dibutyltin bis(isoodyithioglycolate), dibutyltin diacetate, dioctyltin oxide mixtures, dioctyltin oxide, dioctyltin oxide, dibutyltin diisooctoate, dibutyltin dineodecanoate, dibutyltin carboxylate, dioctyitin carboxylate, and combinations thereof.

[0141] The isocyanate catalyst can be utilized in various amounts. For example, in various embodiments, the isocyanate catalyst is utilized in an amount of 0.0001-10, 0.0001-5, 5-10 weight percent, or any other value or range of values ​​therebetween, based on the total weight percent of the reactants or isocyanate. Typically, the amount of catalyst used depends on the temperature of the process. For example, at 150° F., 0.0001% may be utilized, and at room temperature, 0.001-10%, such as 5-10%, such as 0.001-1% may be utilized.

[0142] The isocyanate-reactive component may also include a "curing agent," i.e., a crosslinking agent that, when present, crosslinks the carbon-carbon double bonds of the polydiene polyol. Examples of curing agents include, but are not limited to, organic peroxides, sulfur, and organic sulfur-containing compounds. Non-limiting examples of organic peroxides include dicumyl peroxide and t-butylperoxyisopropylbenzene. Non-limiting examples of organic sulfur-containing compounds include thiuram-based vulcanization accelerators, such as tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), and dipentamethylenethiuram tetrasulfide (DPTT), 4,4'-dithiomorpholine, and the like.

[0143] The isocyanate-reactive components used in forming the novel polyurethane molded articles, or the novel polyurethane foam molded articles, may also include an adhesion promoter. The adhesion promoter may be a silicon-containing adhesion promoter. Adhesion promoters are also commonly referred to in the art as coupling agents or bonding agents.

[0144] The isocyanate-reactive components used in forming the novel polyurethane molded articles, or the novel polyurethane foam molded articles, may also include a wetting agent. The wetting agent may be a surfactant. The wetting agent may include any suitable wetting agent or mixture of wetting agents known in the art.

[0145] The isocyanate-reactive component used in forming the novel polyurethane molded article, or the novel polyurethane foam molded article, may also include various additional additives. Suitable additives include, but are not limited to, defoamers, processing additives, plasticizers, chain terminators, surfactants, flame retardants, antioxidants, water scavengers, fumed silica, dyes or pigments, UV stabilizers, fillers, thixotropic agents, silicones, transition metals, and combinations thereof. The additives may be included in any amount desired by one of ordinary skill in the art. Referring again to the method for forming the novel polyurethane molded article, in any of the above embodiments, the viscosity of one or more individual components used to form the second mixture, including the above-mentioned isocyanate-functional polymer component, the second isocyanate component, and / or the isocyanate-reactive component, has a viscosity of 5 to 10,000 centipoise, as measured according to ASTM standard D2196. In this manner, each component of the second mixture is sufficiently liquid to allow the components to mix and react to form the novel polyurethane molded article or the novel polyurethane foam molded article.

[0146] The novel polyurethane foam molded articles of the present disclosure are formed by combining, mixing and reacting an isocyanate-functional polymer component, a second isocyanate component and an isocyanate-reactive component in the presence of a blowing agent, along with any other components described above, which may be a physical blowing agent, a chemical blowing agent, or a combination of a physical and a chemical blowing agent.

[0147] A physical blowing agent, such as those described above with respect to polyurethane foams that may be used as recycled polyurethane articles, is typically introduced into the second mixture in an amount of from about 0.125 to about 15 parts by weight, e.g., 4 to 6 parts by weight, based on 100 parts by weight of the combined weight of the isocyanate-reactive component and the active hydrogen content present in the blowing agent.

[0148] A chemical blowing agent, such as those described above with respect to polyurethane foams that can be used as recycled polyurethane articles, is typically introduced in an amount such that after reaction, the resulting blowing agent contains from about 0.125 to about 15 parts by weight, e.g., 4 to 6 parts by weight, based on 100 parts by weight of the combined weight of the active hydrogen content present in the isocyanate-reactive component and the blowing agent.

[0149] Thus, the present disclosure provides a simple and efficient method for utilizing recycled polyurethane molded articles into new and useful materials, including novel isocyanate-functional polymer components and polyurethane molded articles or polyurethane foam molded articles.

[0150] In another embodiment, the present invention provides a method for regenerating a preformed polyurethane article, comprising: (a) processing and / or densifying a preformed polyurethane article; (b) heating a toluene diisocyanate composition at a temperature in the range of about 130 to 165° C.; (c) contacting the preformed polyurethane article with the heated toluene diisocyanate composition of (b); and (d) producing a soluble isocyanate-terminated liquid prepolymer; Thereby, the preformed polyurethane molded article is regenerated.

[0151] The term "reclaimed" as used herein refers to the conversion of a preformed material into a base material or element that can in turn be used to produce a "reclaimed" material. In the methods described herein, "reclaiming" a polyurethane article generally refers to converting a previously formed ("preformed") polyurethane article or material (e.g., a preformed polyurethane foam) into an isocyanate-terminated liquid prepolymer that can be used to produce a recycled polyurethane article of material, such as recycled polyurethane foam.

[0152] Any previously formed polyurethane article or material may be used. This includes those that have been used for their intended purpose (e.g., footwear, automobile headliners or front panels, etc.) or those that have not been used for their intended purpose as preformed materials (i.e., unused materials, such as scrap or unused commercial products, etc.). For example, previously formed polyurethane articles or materials include previously formed foams, such as complex formulation foams (e.g., conventional foams, extra soft foams, viscoelastic foams, and Krusader foams). The isocyanate-terminated liquid prepolymer is a base material that can be used to manufacture any polyurethane article or material, regardless of the type of polyurethane article or material from which it is derived.

[0153] In one embodiment, the preformed polyurethane article is a preformed polyurethane foam.

[0154] In various embodiments, the preheat temperature ranges from about 160-165°C.

[0155] In another embodiment, the preheat temperature is maintained throughout the contacting step. In many embodiments, the contacting temperature ranges from about 130°C to 165°C. For example, the contact temperature is maintained at about 130-135°C, 135-140°C, 140-145°C, 145-150°C, 150-155°C, 155-160°C, 160-165°C, 130-140°C, 140-150°C, 150-160°C, 135-145°C, 145-155°C, 155-165°C, 130-145°C, 145-160°C, 135-150°C, 150-165°C, 130-150°C, 135-155°C, 140-160°C, 145-165°C, 130-155°C, 135-160°C, 140-165°C, 130-160°C, or 135-165°C.

[0156] In other examples, the contact temperature is about 125, 130, 135, 140, 145, 150, 155, 160, 165, or 170° C. In various embodiments, the contact temperature ranges from about 160 to 165° C. For example, contact temperatures include 159° C., 160° C., 161° C., 162° C., 163° C., 164° C., 165° C., and 166° C.

[0157] In one embodiment, the method further comprises adding a catalyst after contacting the preformed polyurethane article with the heated toluene diisocyanate composition to reduce regeneration time.

[0158] As noted above, preheating the toluene diisocyanate composition is a means of optimizing (e.g., making faster and / or more efficient) the conversion of the preformed polyurethane article to a polyurethane prepolymer. Further optimization of the reaction includes adding a catalyst to the toluene diisocyanate composition.

[0159] The isocyanate-reactive component used to form the isocyanate-terminated prepolymer may also include one or more catalysts. The catalyst is typically present in the isocyanate-reactive component to catalyze the reaction between the isocyanate component and the isocyanate-reactive component. That is, the isocyanate-reactive component typically includes a "polyurethane catalyst" that catalyzes the reaction between the isocyanate and the hydroxyl functional group. It will be understood that the catalyst is typically not consumed in the exothermic reaction between the isocyanate and the polyol. More specifically, the catalyst typically participates in the exothermic reaction but is not consumed in the exothermic reaction. The catalyst may include any suitable catalyst or mixture of catalysts known in the art. Examples of suitable catalysts include, but are not limited to, gelling catalysts, such as amine catalysts in dipropylene glycol; blowing catalysts, such as bis(dimethylaminoethyl)ether in dipropylene glycol; and metal catalysts, such as organotin compounds, organobismuth compounds, organolead compounds, and the like. In some embodiments, the isocyanate catalyst is an amine catalyst. In other embodiments, the isocyanate catalyst is an organometallic catalyst.

[0160] The isocyanate catalyst may be or may include a tin catalyst. Suitable tin catalysts include, but are not limited to, tin(II) salts of organic carboxylic acids, such as tin(II) acetate, tin(II) octanoate, tin(II) ethylhexanoate, and tin(II) laurate. In one embodiment, the isocyanate catalyst is or includes dibutyltin dilaurate, which is a dialkyltin(IV) salt of an organic carboxylic acid. Non-limiting examples of isocyanate catalysts are commercially available from Air Products and Chemicals, Inc., Allentown, Pennsylvania, under the trademark DABCO®. The isocyanate catalyst may also include other dialkyltin(IV) salts of organic carboxylic acids, such as dibutyltin diacetate, dibutyltin maleate, and dioctyltin diacetate.

[0161] Other suitable, but non-limiting, examples of isocyanate catalysts include iron(II) chloride; zinc chloride; lead octoate; tris(dialkylaminoalkyl)-s-hexahydrotriazines, including tris(N,N-dimethylaminopropyl)-s-hexahydrotriazine; tetraalkylammonium hydroxides, including tetramethylammonium hydroxide; alkali metal hydroxides, including sodium hydroxide and potassium hydroxide; alkali metal alkoxides, including sodium methoxide and potassium isopropoxide; and alkali metal salts of long chain fatty acids having 10-20 carbon atoms and / or lateral OH groups.

[0162] Further examples of suitable, but non-limiting, isocyanate catalysts include N,N,N-dimethylaminopropylhexahydrotriazine, potassium, potassium acetate, N,N,N trimethylisopropylamine / formate, and combinations thereof. Specific examples of suitable trimerization catalysts are commercially available from Air Products and Chemicals, Inc. under the trademark POLYCAT®.

[0163] Further examples of other suitable, but non-limiting, isocyanate catalysts include dimethylaminoethanol, dimethylaminoethoxyethanol, triethylamine, N,N,N',N' tetramethylethylenediamine, N,N-dimethylaminopropylamine, N,N,N',N',N'' pentamethyldipropylenetriamine, tris(dimethylaminopropyl)amine, N,N dimethylpiperazine, tetramethylimino-bis(propylamine), dimethylbenzylamine, trimethylamine, triethanolamine, N,N-diethylethanolamine, N-methylpyrrolidone, N methylmorpholine, N-ethylmorpholine, bis(2-dimethylamino-ethyl)ether, N,N dimethylcyclohexylamine (DMCHA), N,N,N',N',N''-pentamethyldiethylenetriamine, 1,2-dimethylimidazole, 3-(dimethylamino)propylimidazole, and combinations thereof. In various embodiments, the isocyanate catalyst is commercially available from Air Products and Chemicals, Inc. under the trademark POLYCAT®. The isocyanate catalyst may include any combination of one or more of the aforementioned catalysts. In still other embodiments, the catalyst is selected from DABCO TMR, DABCO TMR-2, DABCO HE, DABCO 8154, PC CAT DBU TA 1, PC CAT Ql, Polycat® SA-1, Polycat® SA-102, salt forms, and / or combinations thereof.

[0164] In other embodiments, the catalyst is dibutyltin dilaurate, dibutyltin oxide (e.g., C8-C 10As a liquid solution in phthalate, dibutyltin dilauryl mercaptide, dibutyltin bis(2-ethylhexyl thioglycolate), dimethyltin dilauryl mercaptide, dimethyltin dineodecanoate, dimethyltin dioleate, dimethyltin bis(2-ethylhexyl thioglycolate), dioctyltin dilaurate, dibutyltin bis(2-ethylhexanoate), stannous octanoate, stannous oleate, dibutyltin dimaleate dibutyltin diisooctoate, dibutyltin dineodecanoate, dibutyltin carboxylate, dioctyltin carboxylate, and combinations thereof.

[0165] The isocyanate catalyst for use in forming the isocyanate-terminated prepolymer can be utilized in various amounts. For example, in various embodiments, the isocyanate catalyst is utilized in an amount of 0.0001 to 10, 0.0001 to 5, 5 to 10 weight percent based on the total weight percent of the reactants or isocyanate or any other value or range of values ​​therebetween. Typically, the amount of catalyst used depends on the temperature of the process. For example, at 150°F (about 65.5°C), 0.0001% may be utilized, and at room temperature, 0.001 to 10%, such as 5 to 10%, such as 0.001 to 1% may be utilized.

[0166] In some embodiments, the catalyst comprises dibutyltin dilaurate (DABCO T12).

[0167] In other embodiments, the method further comprises adding diethylene glycol bischloroformate (DIBIS).

[0168] The use of a catalyst in the reaction reduces processing time, but may also result in loss of stability of the product (e.g., liquid polyurethane prepolymer). In some embodiments, loss of stability of the liquid polyurethane prepolymer includes solidification of the polyurethane prepolymer. Compounds that reduce the DABCO T12-induced solidification of the prepolymer over time can be used to maintain the stability and solubility of the prepolymer. In various embodiments, an equal mass of DIBIS is added to the composition and the article fragment mixture.

[0169] In various embodiments, DIBIS reduces DABCO T12-induced solidification of prepolymers over time.

[0170] In some embodiments, DIBIS prevents the decrease in prepolymer stability induced by DABCO T12.

[0171] The method described herein relies on contacting a preformed polyurethane molded article with a heated toluene diisocyanate composition. In various embodiments, the preformed polyurethane molded article is a preformed polyurethane foam having a low density and a large volume. The present invention relies on optimizing the preformed polyurethane foam reclaiming process, including increasing the contact surface of the polyurethane foam in contact with the heated toluene diisocyanate composition described herein. As described above, increasing such contact surface includes processing and / or densifying the preformed polyurethane molded article to obtain pieces of the article (e.g., by grinding, compressing, compacting, etc.), and agitating the polyurethane composition / piece mixture to ensure optimal contact between the pieces and the composition.

[0172] In some embodiments, the toluene diisocyanate composition is selected from the group consisting of a polyurethane composition comprising about 50%-75% toluene-2,4-diisocyanate and about 10%-15% toluene-2,6-diisocyanate; a polyurethane composition comprising about 50%-75% toluene-2,4-diisocyanate and about 15%-20% toluene-2,6-diisocyanate; and a polyurethane composition comprising about 60%-80% toluene-2,4-diisocyanate and about 10%-20% toluene-2,6-diisocyanate.

[0173] In a further embodiment, the present invention provides a method for converting a preformed polyurethane article into a liquid polyurethane material comprising the steps of: (a) processing and / or densifying the preformed polyurethane article; (b) heating a toluene diisocyanate composition at a temperature in the range of about 130-165°C; (c) contacting the preformed polyurethane article with the heated toluene diisocyanate composition of (b); and (d) producing a soluble isocyanate-terminated liquid prepolymer, thereby converting the preformed polyurethane article into a liquid polyurethane material.

[0174] In various embodiments, the preheat temperature ranges from about 160-165°C.

[0175] In another embodiment, the preheat temperature is maintained throughout the contacting step. In many embodiments, the contacting temperature ranges from about 130°C to 165°C. For example, the contact temperature is maintained at about 130-135°C, 135-140°C, 140-145°C, 145-150°C, 150-155°C, 155-160°C, 160-165°C, 130-140°C, 140-150°C, 150-160°C, 135-145°C, 145-155°C, 155-165°C, 130-145°C, 145-160°C, 135-150°C, 150-165°C, 130-150°C, 135-155°C, 140-160°C, 145-165°C, 130-155°C, 135-160°C, 140-165°C, 130-160°C, or 135-165°C.

[0176] In other examples, the contact temperature is about 125, 130, 135, 140, 145, 150, 155, 160, 165, or 170° C. In various embodiments, the contact temperature ranges from about 160 to 165° C. For example, contact temperatures include 159° C., 160° C., 161° C., 162° C., 163° C., 164° C., 165° C., and 166° C.

[0177] In one embodiment, converting the preformed polyurethane article includes producing a polyurethane prepolymer.

[0178] As described herein, the term "liquid form" generally corresponds to the substantial absence of "solid form" as determined by visual inspection. For the purposes of this disclosure, it is recognized herein that a liquid polyurethane prepolymer is considered to be in "liquid form" even if only a small percentage of the total weight of the polyurethane prepolymer remains in solid form, such as less than 5% by weight, more typically less than 1% by weight. This residual material may be in the form of insoluble particles or other materials remaining. These insoluble particles or materials may include various additives, such as inorganic fillers, or other organic materials, and in some cases may be a small amount of residual unconverted reclaimed polyurethane moldings that remain visible as described above.

[0179] Once visual inspection has confirmed the substantial absence of solid forms, the extent of reaction can be confirmed by measuring the isocyanate functional group content (i.e., NCO content, sometimes referred to as free NCO content) of the formed isocyanate functional polymer component based on the total weight of the isocyanate functional polymer component. The total weight of the isocyanate functional polymer component is the sum of the weight of the regenerated polyurethane molding in liquid form and the weight of the isocyanate component (i.e., the weight of the mixture before reaction). The NCO content can be measured by conventional methods known to those skilled in the art of polyurethane analysis according to ASTM D2572, as described above. If the measured NCO content of the isocyanate functional polymer component is less than the NCO content of the isocyanate component, reaction is confirmed.

[0180] In some embodiments, the prepolymers are used in the production of industrial chemicals and / or industrial polymers.

[0181] Below are examples that discuss the conversion of preformed polyurethane molded articles to polyurethane prepolymers for the applications discussed. The following examples are provided to further illustrate embodiments of the invention, but are not intended to limit the scope of the invention. They are typical of those that may be used, but other procedures, methodologies, or techniques known to those skilled in the art may alternatively be used.

[0182] Working Example Example 1 Conversion of polyurethane foam to polyurethane prepolymer in a continuous process. A variety of foams, including complex formulation foams (conventional, hypersoft, viscoelastic and Krusader foams), can be batch digested. The improved process described herein was performed using conventional foams.

[0183] It was found that processing of the foam prior to digestion and its densification allowed for consistent feed rates at laboratory scale. By running the process at the desired temperature of 165 °C by preheating the TDI in an external vessel, the foam and TDI could be fed into the extruder simultaneously to create a suitable reaction environment for the digestion of the foam.

[0184] It was found that a residence time of 5 minutes was desirable in the extruder to facilitate adequate processing. If shorter times were required, it was also found necessary to add a certain amount of polyurethane catalyst, specifically the active tin catalyst DABCO T-12 (dibutyltin dilaurate), to reduce processing times to shorter times of less than 1 minute. However, the addition of catalyst was found to reduce the stability of the resulting liquid samples, and the material solidified over time. This behavior was shown in the laboratory with a test prepolymer system to be mitigated by the addition of an equal mass of diethylene glycol bischloroformate (also known in the industry as DIBIS).

[0185] The reduced volume of TDI and foam in the reactor of a continuous process reduces risk and allows for more control of the process compared to a batch process, but does not limit throughput and provides similar product quality.

[0186] The polyurethane catalyst can be added in a post-process along with the acidifying agent to reduce residence time and improve stability compared to uncatalyzed or catalyzed systems without acidification.

[0187] Continuous addition of foam in conjunction with the extruder allowed for the foam to be fully added to the process because the extruder was able to compress the foam to the required volume of the extruder. For foam cut into 1 inch cubes, the volume difference is about 20 times the liquid, which in batch mode would require either a very large reactor headspace or gradual addition of foam over a period of time.

[0188] Although the invention has been described with reference to the above examples, it will be understood that modifications and variations are encompassed within the spirit and scope of the invention. Accordingly, the invention is limited only by the scope of the following claims.

Claims

1. 1. A method for producing a polyurethane prepolymer, comprising the steps of: a) processing and / or densifying a preformed polyurethane molding; b) preheating the toluene diisocyanate composition at a temperature in the range of about 130 to 165°C; c) contacting the processed and / or densified preformed polyurethane article with the toluene diisocyanate composition; Including, Thereby producing a polyurethane prepolymer. method.

2. The method of claim 1, wherein the toluene diisocyanate composition comprises about 50% to 75% toluene-2,4-diisocyanate and about 10% to 15% toluene-2,6-diisocyanate.

3. The method of claim 1, wherein the toluene diisocyanate composition comprises about 50% to 75% toluene-2,4-diisocyanate and about 15% to 20% toluene-2,6-diisocyanate.

4. The method of claim 1, wherein the toluene diisocyanate composition comprises about 60% to 80% toluene-2,4-diisocyanate and about 10% to 20% toluene-2,6-diisocyanate.

5. The method of claim 1 , wherein the preformed polyurethane article is a polyurethane foam.

6. The method of claim 1 , wherein the processing and / or densifying steps occur before, after, or simultaneously with the preheating step.

7. The method of claim 1 , wherein increasing the preheat temperature decreases processing time.

8. 6. The method of claim 5, wherein the polyurethane foam is selected from the group consisting of fine cell foam, semi-rigid foam, molded foam, and any combination thereof.

9. The method of claim 8, wherein the foam comprises a polyol having a molecular weight in the range of about 1000 to 3600 Da.

10. 6. The method of claim 5, wherein the step of processing and / or densifying the foam comprises crushing the foam to obtain chopped foam.

11. The method of claim 10, wherein the chopped foam pieces have a size ranging from about 500 μm to 5 mm.

12. 11. The method of claim 10, wherein the chopped foam pieces have a size of about 1 mm.

13. 6. The method of claim 5, wherein the processing and / or densifying step comprises using a grinder, processor, shredder, granulator, crusher, compactor or pulverizer.

14. The method of claim 1 , wherein the production is a continuous process.

15. 2. The method of claim 1, wherein the preheat temperature is in the range of about 160-165°C.

16. The method of claim 1, wherein the contacting step comprises contacting about 1-30% w / w of foam with the polyurethane composition.

17. 10. The method of claim 1, further comprising agitating the preformed polyurethane article and the heated polyurethane composition.

18. 2. The method of claim 1, wherein the temperature of the toluene diisocyanate composition is maintained at a temperature in the range of about 130 to 165° C. during the contacting step c).

19. 10. The method of claim 1, further comprising adding a catalyst after step (b).

20. 1. A method for regenerating a preformed polyurethane molded article, comprising the steps of: (a) processing and / or densifying a preformed polyurethane article; (b) preheating the toluene diisocyanate composition at a temperature in the range of about 130-165°C; (c) contacting the preformed polyurethane article with the preheated toluene diisocyanate composition of (b); (d) forming a soluble isocyanate-terminated liquid prepolymer; Including, Thereby, regenerating the preformed polyurethane molding. method.

21. 21. The method of claim 20, wherein the preheat temperature is in the range of about 160-165°C.

22. 21. The method of claim 20, wherein the preformed polyurethane molded article is a preformed polyurethane foam.

23. 21. The method of claim 20, further comprising adding a catalyst after step (b).

24. 24. The method of claim 23, wherein the catalyst comprises dibutyltin dilaurate (DABCO T12).

25. 24. The method of claim 23, further comprising adding diethylene glycol bischloroformate (DIBIS).

26. 26. The method of claim 25, wherein DIBIS reduces DABCO T12-induced solidification of the prepolymer over time.

27. 26. The method of claim 25, wherein DIBIS prevents the decrease in prepolymer stability induced by DABCO T12.

28. The toluene diisocyanate composition is (i) a polyurethane composition comprising about 50% to 75% toluene-2,4-diisocyanate and about 10% to 15% toluene-2,6-diisocyanate; (ii) a polyurethane composition comprising about 50% to 75% toluene-2,4-diisocyanate and about 15% to 20% toluene-2,6-diisocyanate; and (iii) a polyurethane composition comprising about 60% to about 80% toluene-2,4-diisocyanate and about 10% to about 20% toluene-2,6-diisocyanate.

21. The method of claim 20, selected from the group consisting of:

29. 1. A method for converting a preformed polyurethane article into a liquid polyurethane material, comprising: (a) processing and / or densifying the preformed polyurethane article; (b) preheating the toluene diisocyanate composition at a temperature in the range of about 130 to 165°C; (c) contacting the processed and / or densified preformed polyurethane article with the heated toluene diisocyanate composition of (b); (d) forming a soluble isocyanate-terminated liquid prepolymer; Including, thereby converting the preformed polyurethane article into a liquid polyurethane material. method.

30. 30. The method of claim 29, wherein the preheat temperature is in the range of about 160-165°C.

31. 30. The method of claim 29, wherein converting the preformed polyurethane article comprises producing a liquid polyurethane prepolymer.

32. 32. The method of claim 31 , wherein the prepolymer is used in the production of industrial chemicals and / or industrial polymers.

Images