MXPA96005286A - Compound articles of polyurethane produced from recycled polyols and process for your production - Google Patents

Abstract

The present invention discloses compounds (sandwich type elements) having a polyurethane core and at least one coating layer of a fiber reinforced plastic material, which are produced from (a) a polyurethane core which is the product of reaction of a polyisocyanate with a polyol composition obtained by chemical decomposition of polyurethane and / or polyurea wastes, and having an OH number in the range from 100 to 500 mg KOH / g, a water content from 0 to 5 % by weight, and a viscosity greater than 2,000 centipoise (2,000 mPa.s) (20øC) and (b) at least one coating layer of a plastic material reinforced with natural fibers. These compounds are useful in the construction of motor vehicles, furniture construction, machine construction and device construction. These are preferably used in the construction of motor vehicles, in particular, as molded parts inside the motor vehicle.

Description

POLYURETHANE COMPOSITION PRODUCTS PRODUCED FROM RECYCLED POLYOLES, AND PROCESS FOR THEIR PRODUCTION BACKGROUND OF THE INVENTION The present invention relates to polyurethane compounds (sandwich type elements), produced from recycled polyols, and to processes for their production and use, Compounds having a polyurethane core and fiber reinforced coating layers, made of a different material (ie, which is not polyurethane) are used in a wide variety of applications. Such compounds are used, for example, in the production of high-quality structural parts for motor vehicles and bodies for motor vehicles, particularly in the interior of the motor vehicle. Two basic methods are known in the art for the production of composite articles of this kind - the filling method and the coating method. In the filling method, two cover halves (cover layers) are pre-cast, placed in a mold, and the cavity between the covers is filled with a polyurethane foam (PU). In the known coating construction method, a core made of a PU foam is placed in a mold, and covered with a suitable coating material made, for example, of fiber-reinforced plastic, such as epoxy resins or resins. unsaturated polyester REF: 23463 Up to now, polyol compositions recovered from polyurethane or polyurea wastes (ie, recycled polyols) have hardly been used in the production of compounds having a polyurethane core. BRIEF DESCRIPTION OF THE INVENTION It is an object of the present invention to provide high quality composite materials having a polyurethane core, in which the polyurethane was produced from recycled polyols. It is another object of the present invention to provide a process for the production of high quality composite materials having a polyurethane core and an outer layer made of a plastic reinforced with natural fibers, in which the polyurethane core has been produced with a polyol composition recovered from polyurethane and / or polyurea waste. These and other objects, which will be apparent to those skilled in the art, are formed in the form of a polyurethane core from a reaction mixture composed of a polyisocyanate and a recycled polyol. This recycled polyol is obtained by chemical decomposition of polyurethane and / or polyurea waste. This recycled polyol must have an OH number from about 100 to about 500 mg KOH / g, a water content of up to 5% by weight, and a viscosity greater than 2,000 centipoise (2,000 mPa.s) at 20 ° C. A plastic material that is reinforced with natural fibers is applied to this polyurethane core. DETAILED DESCRIPTION OF THE INVENTION The present invention relates to compounds having a polyurethane core and at least one coating layer of a fiber reinforced plastic material. The polyurethane core is produced by reacting a polyisocyanate with a polyol composition obtained by chemical decomposition of polyurethane and / or polyurea waste. The polyol composition has an OH number in the range from about 100 to about 500 mg KOH / g, a water content from 0 to 5% by weight, and a viscosity of more than 2,000 centipoise (2,000 mPa. s) (20 ° C). The coating or outer layer is made of a plastic material re-forced with natural fibers. It is surprising that high quality polyurethane cores can be produced for composite articles altogether using polyol compositions that meet these requirements, because polyols having a much higher OH number have been used in known processes (in most cases in the interval from 300 to 1,000) and a considerably lower viscosity (in most cases in the range of <2,000 centipoises (< 2,000 mPa.s) (20 ° C)). The required characteristics of the polyol for the practice of the present invention can be achieved by adjusting the properties of the recycled polyols obtained directly by chemical decomposition of polyurethane and / or polyurea wastes by means of additives described more precisely below. The compounds of the present invention are in the form of sandwich-type elements containing, in addition to a polyurethane core formed of a recycled polyol, at least one coating layer made of a plastic material, preferably an epoxy resin or a poly resin. - unsaturated ester, and natural fibers as reinforcement. The coating layer is preferably composed of a fiber-reinforced plastic material. Any of the known fibrous natural fibers, particularly the fibers of banana, flax fibers, jute fibers, hemp fibers, henequen fibers and / or coconut fibers in the form of waste fiber, cross-linked fabric and woven fabric are fibers natural agglomerates. These fibrous materials can reinforce epoxy-unsaturated polyester resins, polyurethane (PU) resins, melamine resins, vinyl resins or even thermoplastic powders. These adhesives or binders can be introduced and applied by spraying, rolling, coating with a blade, or casting. When using the preferred PU resins, the adhesives may also contain recycled PU materials. The compounds of the present invention are suitably sandwich-type construction, comprising a cover layer A or coating, composed of a plastic material reinforced with natural fibers, a layer B of the core, composed of a polyurethane foam formed in pairs. -tir of a recycled polyol, and if desired, an additional layer that is either composed of the same material as layer A or composed of a different material. Then decorative materials such as films, molded coatings, textiles or carpets can be applied to the outer layer. This application can be conducted in a separate operation, or even in a single production stage (one-stage method), or by pressing back in a known way (direct coating) directly on the outer surfaces of the layer (s). ) of the coating. In multi-layer sandwich structures, additional layers of different materials may optionally also be included.

Any of the common reaction products of an isocyanate and the commonly used diols and / or polyols (for example polyesters or polyethers) can be used as the polyurethane or polyurea wastes that are decomposed to produce the polyol compounds used in the practice of the present invention. The present invention also provides a process for the production of compounds (sandwich elements) having a polyurethane core and at least one fiber reinforced cover layer. In this process, a polyisocyanate is reacted with a polyol composition obtained by chemical decomposition of polyurethane and / or polyurea wastes and optionally other auxiliary substances and additives. The polyol composition should have an OH number in the range of from about 100 to about 500, preferably from about 200 to about 450, more preferably from about 250 to about 400 mg of KOH / g, a content of water from 0 to about 5% by weight, preferably from about 0.2 to about 2% by weight, more preferably from about 0.5 to about 1% by weight, and a viscosity at 20 ° C of more than 2,000 centipoises (2,000 mPa s), preferably from about 3,000 to about 20,000 centipoises (about 3,000 to about 20,000 mPa s), more preferably from about 5,000 to about 10,000 centipoises (about 5,000 to about 10,000) mPa.s). At least one cover layer of a plastic material reinforced with natural fibers is applied to the polyurethane core. In the process of the present invention, any of the known auxiliary substances and additives may be used. Examples of such auxiliary substances and additives include: release agents, blowing agents, re-fillers, catalysts and flameproofing agents. The process of the present invention can be carried out by the filling method (deposit) or by the coating method. Both methods of construction by filling and construction by coating are known to those skilled in the art. In the filling method, two cover halves (e.g., roof layers of a plastic material reinforced with natural fibers) are pre-ground and placed in a mold. The cavity between the covers is filled using the PU foam produced according to the present invention. In the coating construction method, a core made of PU foam produced in accordance with the present invention is placed in the mold, and then coated with a coating material reinforced with natural fibers, such as an epoxy resin or polyester siina reinforced with natural fibers. The compounds of the present invention that contain a cellular PU core are preferably produced by the coating construction method, using recycled polyols. Any of the known conventional blowing agents and auxiliaries (e.g., release agents) can be added. If an external release agent is not added during the production of the compounds of the present invention by the method of coating construction in a mold, then a particularly strong adhesive bond is obtained between the polyurethane core material and the coating material. , without any need to finish or prepare the coating and / or core layer. Any of the known plastic materials reinforced with natural fibers can be used as the coating layer in such a process. The polyols used in the practice of the present invention can be obtained by chemical decomposition of any polyurethane and / or polyurea wastes. Even the decomposition products of polyurethane and / or polyurea composites can be used. These composite materials may be composed of PU and other materials, such as thermoplastics. When the material that is not PU is a thermo-plastic, the thermoplastic material must be separated from the polyurethane largely before recycling the PU. Such composite material may be, for example, an automotive control panel made of a glass fiber reinforced PU support, a soft texture PU foam as a back-fill material, or an outer aliphatic PU film as a decorative and cover layer. Methods for chemically decomposing polyurethane and / or polyurea wastes into polyol compounds are known. Examples of such known processes include aminolysis, alcoholysis and glycolysis. These methods have already been described in detail in the prior art. See, for example,. RaBhofer, Recycling von Polyurethan-Kunststoffen, Hüthig-Verlag, Heidelberg, 1994.

The polyol compositions used in the practice of the present invention are preferably obtained by glycolysis of polyurethane and / or polyurea waste in a known manner. Crushed or finely milled polyurethane and / or polyurea waste is reacted at temperatures from 160 to 240 ° C with glycols, preferably diethylene glycol, in a waste weight ratio: glycol from 10: 1 to 1: 2 , preferably from 5: 1 to 1: 1. After stirring for from about 0.5 to 10 hours, a liquid product having the following characteristics is obtained: an OH number in the range from 20 to 1.070 mg KOH / g, a water content in the range from 0 to 5% by weight, a viscosity at 20 ° C of > 2,000 centipoises (^ 2,000 mPa. S), At very high OH numbers, the viscosity may also be below 2,000 centipoise (2,000 mPa.s) (20 ° C). Since the polyol compositions obtained directly from the chemical decomposition of polyurethane and / or polyurea wastes generally do not meet the requirements of a polyol suitable for use in the practice of the present invention, the OH number, content of Water and / or viscosity of the decomposition product are usually adjusted by incorporating additives. For this purpose, mixtures of known additives, such as cross-linking agents, cell stabilizers, flow-promoting agents, release agents, catalysts, blowing agents, etc., are added in amounts which amount to about 2 to 50% by weight, based on the weight of the recycled polyol used. Mixes of additives usually have an OH number from 300 to 1,050 mg KOH / g, a viscosity from 100 to 5,000 centipoise (100 to 5,000 mPa.s) (20 ° C), a water content from 0 to 10% by weight, and an acid number from 0 to 100 mg of KOH / g. It is surprising that the polyols which satisfy the OH number, water content and viscosity requirements of the present invention, which are obtained by chemical decomposition of polyurethane and / or polyurea waste, are entirely suitable for the production of high quality compounds. of polyurethane having a sandwich type structure, because generally when new (ie, non-recycled) polyols are used in such processes, these polyols have considerably higher OH numbers (from 500 to 1,000). The viscosity of the polyol compounds used in the prior art is also generally considerably higher (mainly in the viscosity range of <2.00 centipoise (<2,000 mPa.s) (20 ° C)). Therefore it was not expected that the polyol compositions obtained from polyurethane and / or urea waste could be processed to high quality polyurethane compounds despite their very high viscosity and their OH number less (reduced activity).

The polyurethane compounds of the present invention are useful for the production of high quality structural components, for a variety of applications. The production of these compounds makes it possible to use waste generated materials in an advantageous manner, without sacrificing the mechanical properties of the composite product. The polyols obtained from the chemical decomposition of polyurethane and / or polyurea waste can be reacted with any of the known polyisocyanates. Suitable polyisocyanates include: aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic polyisocyanates. Such polyisocyanates are described, for example, by W. Siefgen in Justus Liebigs Annalen der Chemie, 362, pages 75 to 136. Useful polyisocyanates include those represented by the general formula: Q (NCO) n in which n represents 2 to 5, preferably from 2 to 3, and Q represents an aliphatic hydrocarbon radical having from 2 to 18 (preferably from 6 to 10) carbon atoms, a cycloaliphatic hydrocarbon radical having from 4 to 15 (preferably from 5 to 10). carbon atoms, or an aromatic hydrocarbon radical having from 6 to 15 (preferably from 6 to 13) carbon atoms. Examples of such polyisocyanates are given in German Offenlegungsschrift 2,832,253, pages 10 to 11. Particularly preferred are commercially available polyisocyanates, such as 2,4- and 2,6-toluene diisocyanate, and any mixture of these isomers ("TDI" ); diphenylmethane diisocyanate ("MDI") and polyphenylenepolymethylene polyisocyanates, which are prepared by aniline-formaldehyde condensation and subsequent phosgenation; as well as polyisocyanates having carbodiimide groups, urethane groups, allophanate groups, isocyanurate groups, urea groups or biuret groups ("modified polyisocyanates"). Particularly preferred are the modified polyisocyanates which are derived from 2,4- and 2,6-toluene diisocyanate or 4,4'- and / or 2,4'-diphenylmethane diisocyanate. The polyurethane compounds (sandwich type elements) of the present invention are useful in the construction of motor vehicles, furniture construction, machine construction and apparatus construction. These polyurethane compounds are advantageously used in the construction of motor vehicles, particularly in the interior of the motor vehicle. In addition to having low weight with high strength, the sandwich elements of the compounds of the present invention have a particularly low content of substances that can be emitted and extractable. In the motor vehicle sector, these compounds can be used, for example, as bi- and / or three-dimensional molded parts, such as concealable panels or covers, panels for interior doors, supports for control panels, supports for boards of instruments, air ducts, cable covers, cable ducts and trunk lining. They can also be processed to form housings and covers for housings, pallets, supports for small loads, coatings, vertical and horizontal structural components, screens, mosaic parquet, etc. In the furniture sector, the polyurethane compounds of the present invention can also be used as a substitute for tropical wood, particularly in the form of imitation plywood. The following Examples are proposed to illustrate the invention without, however, limiting the scope thereof. EXAMPLES Example 1 (Chemical decomposition of polyurethane waste by glycolysis) A granular material, having a maximum particle size of 8 m, and glass fiber reinforced polyurethane urea compound, having a density of 1.26 g / cm 3, it was subjected to glycolysis. 4 kg of diethylene glycol were placed in a 20 1 flask equipped with a stirrer and a heating jacket, covered with nitrogen and preheated to 220 ° C. 8 kg of granulated polyurethane urea was introduced into the hot mixture in portions. under a nitrogen atmosphere. The addition was carried out at such a rate that at all times there was a mixture that could be stirred. When the addition of the granular material was complete, the mixture was stirred at 200-210 ° C for a period of 90 minutes, cooled to 160 ° C, then mixed with 0.2 kg of ethyl acetoacetate, and stirred at this temperature for an hour. A liquid product composed of recycled polyols was obtained, which leaving it at rest formed two phases. The product had the following properties: OH number = 353 mg KOH / g NH number = 33 mg KOH / g Acid number = 0.07 mg KOH / g Viscosity = approx. 20,000 centipoise (20,000 mPas.s) (20 ° C) Example 2 (Production of a cellular polyurethane core for a compound according to the present invention) A mixture of additives was added to the recycled polyols obtained by glycolysis in Example 1 . This admixture of additives was used in an amount that was 25% by weight, based on the total weight of the polyol. The mixture of additives had the following properties: OH number = 400 mg KOH / g Water content = 2.6% by weight Viscosity = 1,500 centipoisee (1,500 mPa.s) (20 ° C) The resulting polyol formulation had the following properties: OH number = about 380 mg KOH / g Water content = about 1% by weight Viscosity = about 3,500 centipoisees (about 3,500 mPa.s) (20 ° C) This polyol formulation was injection molded with reaction with polyisocyanate (crude MDI) in a known manner, to produce a cellular molded article. An external release agent was not used. A molded article having an apparent bulk density of 400 kg / m was obtained. Example 3 (Production of a compound (sandwich type element) according to the present invention) Example 3a Outside the mold, coconut fiber plush having a substance weight of 600 was impregnated and coated. 2 g / m with a PU matrix material (available commercially under the name Baypreg from Bayer AG) by spraying in a known manner. A mold (steel, 120 ° C, 300 x 300 x 8 mm) was covered with a PU cover layer reinforced with coconut fiber produced as described above, a polyurethane core produced as described in Example 2, and an additional cover layer of PU reinforced with coconut fiber. Then the mold was closed. After 2 minutes at 120 ° C and a pressure of 50.95 kg / cm (50 bar), a sandwich-type element bonded by adhesion was released. Example 3b A compound was produced in the same manner as described in Example 3a), with the exception that a decorative PVC / ABS film was placed on one of the cover layers, before the mold was closed. After 2 minutes at 120 ° C and at a pressure of 50.95 kg / cm (50 bar), a sandwich-type element bonded by adhesion, and having an additional decorative layer, was released. All sandwich-type elements produced in accordance with the present invention exhibited a very good adhesive bond between the core and the cover layer, good dimensional stability and strength. Although the invention has been described in detail in the foregoing for the purpose of illustration, it is to be understood that such detail is only for that purpose, and that variations may be made thereto by those skilled in the art without departing from the spirit and scope of the invention. the invention, except when it may be limited by the claims.

It is noted that in relation to this date, the best method known to the applicant to carry out the practice It is noted that in relation to this date, the best method known to the applicant to implement the aforementioned invention, is which is clear from the present description of the invention.

Having described the invention as above, property is claimed as contained in the following:

Claims (10)

1. CLAIMS 1. The caipuesto or article crpi This ajim-arJ a ro-iuteta-no core and at least one outer layer, characterized because: a) the polyurethane core is the reaction product of 1) a polyisocyanate with 2) a polyol obtained by chemical decomposition of polyurethane and / or polyurea waste, having an OH number from about 100 to about 500 mg KOH / g, a water content of up to 5% by weight, and a higher viscosity 2,000 centipoise (2,000 mPa.s) at 20 ° C and b) the outer layer is a plastic material that is reinforced with natural fibers. The compound according to claim 1, characterized in that the outer layer is a plastic that is reinforced with selected fibers of banana fibers, flax fibers, jute fibers, hemp fibers, henequen fibers, coconut fibers and combinations of these fibers. 3. The compound according to claim 2, characterized in that the plastic of the outer layer is polyurethane. 4. The compound according to claim 3, characterized in that the polyurethane core is cellular polyurethane. 5. The compound according to claim 2, characterized in that the polyurethane core is cellular polyurethane. 6. The compound in accordance with the claim 1, characterized in that the plastic of the outer layer is polyurethane. 7. The compound in accordance with the claim 1, characterized in that the polyurethane core is cellular polyurethane. The compound according to claim 1, characterized in that the polyol used to produce the polyurethane core is obtained by glycolysis of polyurethane and / or polyurea waste. 9. A process for the production of the compound according to claim 1, characterized in that it comprises coating the polyurethane core with a plastic reinforced with natural fibers, which forms the outer layer. 10. The process according to claim 9, characterized in that the polyol used to produce the polyurethane core is obtained by glycolysis of polyurethane and / or polyurea waste.