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US008546470B2

(12) United States Patent (10) Patent N0.: US 8,546,470 B2 Joyce et a1. (45) Date of Patent: *Oct. 1, 2013

(54) CELLULOSIC INCLUSION 5,075,359 A * 12/1991 Castagna et a1...... 524/13 COMPOSITION AND 5,346,773 A * 9/1994 Simoens ...... 428/476.9 MOLDING THEREOF 5,403,667 A * 4/1995 Simoens .. 428/479.6 6,294,602 B1* 9/2001 Shimo et a1. 524/394 6,376,584 B1* 4/2002 Galbo et a1...... 524/102 (75) Inventors: Robert C. Joyce, Lambertville, MI 6,682,789 B2 * 1/2004 Godavarti et a1...... 428/34 (US); Andrew Hopkins, Sylvania, OH 6,835,764 B2 * 12/2004 Leckey et a1...... 524/15 (US); Harutun George Karian, 7,862,746 B2 * 1/2011 Kaspers et a1. 252/397 Brighton, MI (US) 8,122,996 B2 * 2/2012 Kajihara et a1. 181/169 2003/0022962 A1* 1/2003 Cook et a1. 523/164 (73) Assignees: Innovative and Molding, 2004/0126515 A1* 7/2004 Yarmoska .. 428/34.1 2005/0058822 A1* 3/2005 Ittel ...... 428/304.4 Lambertville, MI (U S); RheTech, Inc., 2006/0084764 A1* 4/2006 Hanna et a1. 525/242 Whitmore Lake, MI (U S) 2006/0091578 A1* 5/2006 Bravo et a1. 264/122 2007/0208110 A1* 9/2007 SigWorth et a1. 524/13

( * ) Notice: Subject to any disclaimer, the term of this 2009/0182071 A1* 7/2009 Joyce ...... 524/13 patent is extended or adjusted under 35 2010/0062670 A1 * 3/2010 Bastioli et a1...... 442/327 USC 154(b) by 0 days. This patent is subject to a terminal dis OTHER PUBLICATIONS claimer. Andrady, Plastics and the Environment, 2003, John Wiley and Sons, Inc. Chapter 2* (21) App1.No.: 13/158,742 Perez et al., Macromol. Symp. 2005, 221,247-256.* (22) Filed: Jun. 13, 2011 , An A-Z reference, Ko sc sis, Kluwere Academic Pub lishers, 1999, p. 148-157.* (65) Prior Publication Data , Kohan et al., Ulmann’s Encyclopedia of Industrial Chemistry, 2003.* US 2011/0245380 A1 Oct. 6, 2011 * cited by examiner Related US. Application Data (63) Continuation of application No. 12/354,310, ?led on Primary Examiner * Liam Heincer Jan. 15, 2009, noW abandoned, Which is a continuation of application No. 12/321,093, ?led on Jan. 15, 2009, (74) Attorney, Agent, or Firm * Blue Filament LaW PLLC; noW Pat. No. 7,994,241. Avery N. Goldstein (60) Provisional application No. 61/021,234, ?led on Jan. 15, 2008. (57) ABSTRACT (51) Int. Cl. A cellulosic inclusion-thermoplastic composition that C08L 97/02 (2006.01) includes cellulosic inclusions and a thermoplastic polyole?n C08L 1/00 (2006.01) that forms a matrix in Which the cellulosic inclusions are C08G 18/38 (2006.01) dispersed. A maleated and a polar thermoplastic (52) US. Cl. polymer resin of a or are provided to USPC ...... 524/14; 524/35 improve adhesion between the cellulosic inclusions and the (58) Field of Classi?cation Search thermoplastic polyole?n. The polar thermoplastic polymer USPC ...... 524/13, 14, 35 resin is characterized by a melting temperature greater than See application ?le for complete search history. that of the thermoplastic polyole?n. The composition as pro (56) References Cited vided has increased break tensile strength relative to a com position devoid of the polar thermoplastic polymer resin but U.S. PATENT DOCUMENTS otherwise is unchanged. The break tensile is measured at 230 Celsius and at an elongation rate of 50 millimeters per minute. 4,323,625 A * 4/1982 Coran et a1...... 428/361 4,403,007 A * 9/1983 Coughlin 428/95 4,438,228 A * 3/1984 Schenck .. .. 524/109 5,030,662 A * 7/1991 Banerjie ...... 521/435 24 Claims, 7 Drawing Sheets

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,wa@ US 8,546,470 B2 1 2 CELLULOSIC INCLUSION monly being achieved through ?ber pre-processing or encap THERMOPLASTIC COMPOSITION AND sulation of the ?ber in the thermoplastic. MOLDING THEREOF Wood ?bers are hydrophilic materials that are poorly Wet by molten hydrophobic thermoplastic resulting in CROSS-REFERENCE TO RELATED poor ?oW characteristics, dif?cult processability, and prema APPLICATIONS ture ?ber pull-out, all of Which leads to molded products With poor appearance and inferior mechanical properties. Property This application claim is a continuation in part of US. improvement has been addressed through the use of “com patent application Ser. No. 12/321,093 ?led 15 Jan. 2009 and patibiliZing” materials that adhere to both the polar ?bers and is a continuation in part of US. patent application Ser. No. the non-polar polymer resin. Most common has been the use 12/354,310 ?led 15 Jan. 2009, both of Which in turn claim of a maleic anhydride grafted polypropylene . See, priority bene?t of US. Provisional Patent Application Ser. for example, US. Pat. No. 5,948,524 and “Wood Flour Filled Polypropylene Composites: Interfacial Adhesion and Micro No. 61/021,234 ?led Jan. 15, 2008, these prior applications mechanical Deformations”, L. Danyadi et al., Polym. Eng. & are incorporated herein by reference. Sci. 47(8), pp 1246-1255 (August 2007). Typically, Wood ?our-polypropylene composite (WPC) pellets are manufac FIELD OF THE INVENTION tured via compounding extrusion equipment folloWed by thermoplastic post-forming processes such as injection mold The present invention in general relates to a composition ing or pro?le extrusion. The engineering of desirable process containing cellulosic inclusions dispersed in a thermoplastic 20 ing and physical properties into a WPC is further complicated polymeric matrix and in particular to such a composition With by the addition of other substances such as reinforcing glass improved distribution of the cellulosic inclusions and physi ?ber ?ller, non-cellulosic particulate ?llers, colorants and cal properties. mold release compounds.As many physical property require ments are associated With homogeneous distribution of ?llers BACKGROUND OF THE INVENTION 25 and the matrix Wetting of those ?llers by the ole?nic matrix, a chemical coupling package ideally is compatible not only It is typical in the that reinforcements and With WPC itself, but also glass ?ber ?lled and non-cellulosic ?llers are used to improve the properties of said materials. particulate ?lled forms thereof. Commonly, this is done to achieve improvement in physical None of the Wood polymer composite materials that have properties such as tensile strength, ?exural modulus and 30 been developed to date afford a completely satisfactory set of impact strength. Common ?llers are tale, calcium carbonate performance characteristics and as such are de?cient for end and other minerals. By far the most common ?brous rein use applications in one or more of, e.g., poor physical prop forcement is glass. Glass ?bers impart high strength, dimen erties, Water resistance, undesirable odor, poor processability sional stability and heat stability. There are commercial and/or excessive cost. These shortcomings stem from draW requirements that glass ?ber and other mineral ?llers cannot 35 backs in a forming process having poor melt ?oW character fully meet. istics due to inadequate adhesionbetWeen the dispersed Wood For example, glass ?bers increase the density and cost of ?bers and thermoplastic polymer matrix at high Wood ?ber the material and abrade processing equipment. In addition, loading levels. glass ?bers are manmade, non-reneWable materials With a It is evident that to make a practical Wood composite considerable environmental impact. 40 end product, such as an injection molded spindle, toys, auto Cellulo sic materials have been evaluated as reinforcements motive parts, etc., the Wood plastic must in the past. In particular, Wood ?bers from a variety of sources be dried prior to processing. Additionally, Wood plastic com have been extensively studied, together With the effects and pounded pellets can be blended With other virgin or com improvements that common processing aids Would be pounded polymers in pellet form. These additional pellets expected to impart to such systems. Typically, Wood ?bers 45 may have ingredients for reinforcement such as glass and or have a loWer density (1.3 g/cc) than glass ?bers (2.6 g/cc) or mineral, to produce various types of molded products that are other minerals (e.g. Wollastonite, 2.9 g/cc). From an ecologi tailored to particular end-use applications. cal point of vieW, Wood ?bers have a reduced environmental Thus, there exists a need for a thermoplastic composition impact. With improved cellulosic inclusion-thermoplastic interac Chemically, Wood ?bers (and ?ours) are not pure cellulose, 50 tions relative to conventional composites so as to create supe they contain at least tWo other major components, hemi rior performance molded articles. cellulose and ligniniWith different varieties and different species of planting containing different ratios of these con SUMMARY OF THE INVENTION stituents. When the Wood ?bers are processed With thermo plastic resins at temperatures that exceed 2000 C., the ?bers 55 A cellulosic inclusion-thermoplastic composition includ exhibit severe discoloration and thermal degradation. There is ing cellulosic inclusions and a thermoplastic polyole?n that also signi?cant off-gassing and objectionable odors, princi form a matrix in Which the cellulosic inclusions are dispersed pally due to impurities and the lignin that modify manufac and a maleated polymer, and a polar thermoplastic polymer turing process and create a Worker safety concern. It has also resin of a polyamide or polyester are provided to improve been shoWn that processing temperatures above 2000 C. 60 adhesion betWeen the cellulosic inclusions and the thermo reduce the physical property improvements delivered by the plastic polyole?n. The composition as provided has increased ?bers (Klason, et al., Inter. J. Polymeric Mater, Volume 10, p break tensile strength relative to a composition devoid of the 175 (1984)). Furthermore, When the moisture present during polar thermoplastic polymer resin With the break tensile mea the processing of the cellulosic materials is not controlled sured at 230 Celsius and at cross-head speed of 50 millimeters and/ or eliminated, performance of the resultant composite is 65 per minute. compromised. Management of moisture in the materials and A method of making a cellulosic inclusion-thermoplastic the molded parts has proved costly and dif?cult, most com composition includes blending the thermoplastic polyole?n US 8,546,470 B2 3 4 together With the cellulosic inclusions, maleated polymer, crystalline polyamide. This is realiZed in the compounding of and the polar thermoplastic polymer resin to form a blend. the Wood plastic compound and When creating a hybrid injec The blend is then formed into a solid article in Which the tion molded extrudate to make a molded article. The com maleated polymer and the polar resin interact synergistically pounding extrusion temperatures are set at 460-480° F. in the to promote adhesionbetWeen the cellulosic inclusions and the ?rst mixing Zone of the tWin screW extruder to provide the thermoplastic ole?n as noted by an increased break tensile necessary softening state of the polyamide to for an effective strength relative to an otherWise identical composition devoid compatibiliZation bridge betWeen the polyole?n and MAPP of the resin. Melt blending and forming of the solid article by molecules. The heat temperature pro?le, not including the extruding are particularly bene?cial aspects of the present ?rst Zone, set at 460 to 480° F., has seven additional tempera invention. Melt blending at or beloW the temperature that is ture Zones in the heta pro?le, having subsequent step doWn the melting point of the polar thermoplastic resin yet at or reductions of approximately 10-20° F. This step doWn-heat above the melting temperature for the thermoplastic ole?n pro?le provides the necessary mixing, dispersion and devola represents a particularly desirous processing condition. tiZation Which result in the compatibiliZation of the Wood A Wood plastic composite composition is provided con ?our, polyole?n, polyamide, lubrication and MAPP ingredi taining a semi crystalline polyole?n, maleic anhydride ents. grafted polyole?n, a crystalline polar polymer, With cellulo sic A combination of a Wood plastic composite pellet With a ?bers at 1 to 80 Wt percent that are processed at a reduced virgin or co reinforced pellet at various loadings, referred to a moisture yield product at 1 percent and preferably less than hybrid blend, requires much loWer processing temperatures 0.5 percent ?nal moisture content. This composition can pro With minimal shear for injection molding of parts. The inj ec duce molded article that exhibits an improved structural prop 20 tion molding temperatures are set at 370-390° F. With a 2.5 to erty and in particular break tensile strength that has been 1 screW ratio. Hence, the crystallinity of the polyamide helps elusive to the Wood composite industry. expand the hybrid blend processing WindoW, including the To produce an extruded Wood plastic composite pellet, in Wood, Which requires less heat input and shear for melting most instances, the Wood ?ber has gone through a drying and dispersing all ingredients. Hence, the invention provides process and must be reprocessed again before compounding 25 an opportunity to load more ?brous reinforcement in a poly because of the a?inity of moisture, Which can range from 8 to ole?n based concentrate or composite for injection molding. 14 percent in most instances. The reprocessing of the Wood Consequently, in both compounding process and injection ?ber, Which is called classi?cation, Will help reduce moisture molding, Wood plastic compound does not require excessive content and create a ?ber siZe that Will effectively distribute in lubrication or higher melt ?oW base polymer to mold pellets, the polymer matrix. The Wood ?bers are noW of a ?our con 30 spindle, car parts, etc., Which is a detriment to mechanical sistency of a 20-120 mesh siZe. In addition, to classi?cation, properties of the polyole?n based Wood composite. The there are other forms of heat i.e. hot air or ovens that can help design of the Wood plastic compound can also achieve supe reduce Wood ?our moisture and prepare for compound extru rior strength to Weight ratios and cost advantage for a com sion. When compounding these ingredients, an intensive mix pounded Wood plastic compounded pellet that is let-doWn ing or blending With a polymer, additives, lubricants, etc., to 35 into injection molded parts. By drying or not drying the Wood make a Woodplastic composite pellet, more moisture removal plastic compounded pellet you can produce a cellular or solid is necessary. The compound extruder Will have a single or state molded article. You can also utiliZe a chemical bloWing multiple vents and or vacuums pull off or extract moisture and agent to help promote a cellular composition in either a com or gas. After the ?nished pellet is manufactured, it is a high pounded pellet or injection molded part. By introducing a gas loading of Wood ?our Will lack dispersion of couplings, espe 40 bloWing agent, i.e. nitrogen, at the injection molding machine cially polypropylene, a thermoplastic polyole?n and it is dif noZZle and or die, you can help create a controlled cellular ?cult to Wet out all ?bers to promote adequate Wood ?ber structure by pressure. Pressure is also effective in the Wood adhesion. Furthermore, the process WindoW needs to be plastic compounding process in squeeZing moisture and or increased With highly ?lled Wood compositions, burning of gas out of the extrudate to make pellets. If pellets are pro Wood ?ber is common. 45 cessed properly With an e?icient die, minimal voids Will be The crystalline, polyamide 6, Which can be also a copoly produced internally in the pellet. These voids hold moisture. mer, is amorphous in the molten state but upon cooling to Respective levels of pellet moisture is less than 0.5 percent. 200° C. it tends to crystalliZe very rapidly. Furthermore, the The moisture levels Will re?ect the compaction of the pellets. polyamide 6, Will tend to be mostly in the crystalline state, In addition, there Will be no surface moisture due to the particularly When it is in contact With the Wood ?our particles 50 polymer skin that Will be visible on the surface. These pellets that have hydroxyl groups that form strong H-bonds and can range in siZe from 0.100 to 0.250. covalent amide bonds With the nitrogen atom on the PA-6 molecule. The interaction betWeen the hydroxyl groups and BRIEF DESCRIPTION OF THE DRAWINGS the polyamide Will help to reduce moisture generation at the surface of the Wood plastic compounded pellets at elevated 55 FIG. 1A is a bar graph of tensile strength for ?ve duplicate processing temperatures. The polyamide combined With 2 Wt samples each of a comparative I containing maleic anhydride % MAPP Will increase interfacial adhesionbetWeen the Wood grafted polyole?n and lacking the polar polymer resin com ?ber and a polyole?n matrix. The increase in the interfacial ponent and relative to an inventive compositionA per Table 1 adhesion Will help prevent Wood ?ber pull-out at elevated collected at 23° Celsius and a cross-head speed of 50 milli service temperature. There Was also a great improvement in 60 meters/minute; the reduction in part Warp age and sink and the ability to FIG. 1B is a plot of tensile strength-break at 23° Celsius chemically form a part. and an elongation rate of 50 millimeters/minute as a function It so happens that the PA-6 ingredient does not remain a of polyole?n-cellulosic inclusion-maleated polymer content separate ?brous resin after the initial compounding extrusion for an inventive composition With either 20% glass ?lled, step. The extrudate is noW an alloy that is of a heterogeneous 65 chemically coupled, polypropylene (B-diamond data point) composition. Consequently, the processing WindoW of the or polypropylene copolymer (C-square data point) With prior Wood plastic compound is increased by the addition of the art compositions plotted for a cellulosic-thermoplastic devoid US 8,546,470 B2 5 6 of maleic anhydride grafted polypropylene for a comparative represent a preferred form of cellulosic inclusion. More pref formulation II (circle data point) and for a comparative for erably, the cellulosic inclusions include Wood ?bers in a form mulation III of cellulosic material-thermoplastic containing commonly referred to in the art as Wood ?our. The preferred 2-3% maleic anhydride grafted polypropylene (MAPP) and cellulosic reinforcement is a Wood ?our, but can be any com devoid of polar thermoplastic polymer resin (triangle data bination of one or more other natural ?bers, such as jute, points); sWitch grass, Wheat straW, bamboo, Wood, cotton, ?ax ?ber, FIG. 2A is a bar graph of ?exural strength-yield for the rice hulls, and combinations thereof. Sources of Wood ?our compositions of Table 1; illustratively include pine, oak, maple, poplar, among other FIG. 2B is a plot of ?exural strength-yield for the compo deciduous and coniferous Woods. Through the use of Wood sitions of FIG. 1B as a function of polyole?n-cellulosic inclu ?our that is a byproduct of other manufacturing processes, it sion-maleated polymer content; is noted that a material that otherWise Would end up in a FIG. 3A is a bar graph of ?exural modulus-chord for the land?ll or incinerated is utiliZed to reduce overall environ compositions of Table 1; mental impact. It is appreciated that cellulosic inclusions vary FIG. 3B is a plot of ?exural modulus-chord for the com greatly in Water content based on the source and season of positions of FIG. 1 1B as a function of polyole?n-cellulosic cellulosic inclusionusage. As Water content is knoWn to affect inclusion-maleated polymer content; and interfacial adhesion betWeen Wood ?our and polypropylene, FIG. 4 is a plot of melt ?oW rate for the compositions tested preferably a cellulosic inclusion in an inventive composition in FIGS. 1B, 2B and 3B. is dried to a cellulosic inclusion Water content of preferably less than 15 Weight percent of the inclusions and more pref DETAILED DESCRIPTION OF THE PREFERRED 20 erably to less than 10 Weight percent, and most preferably EMBODIMENTS betWeen 0.5 and 8 total Weight percent of the inclusions being Water before intermixing With other inventive composition The present invention has utility as a cellulosic inclusion components. Typically, cellulosic inclusions have a mean therrnoplastic material With superior properties relative to particle siZe of betWeen 10 and 200 standard US mesh and conventional Wood polypropylene composites (WPCs). An 25 preferably betWeen 20 and 100 mesh, and most preferably inventive composition facilitates the production of a variety betWeen 40 and 80 mesh. It is appreciated that cellulosic of articles that could not previously be formed With accept inclusion processing to retain inherent ?ber length of the able properties. One aspect of the present invention relates to inclusions promotes superior physical properties to the result a composition of a compounded Wood-polyole?n pellet used ant article. Pre-pelletiZing of the cellulosic inclusions or for injection molding, extrusion, . The 30 introduction thereof in later stages of compounding are Wood plastic compounded pellet contains Wood ?our at 1 to knoWn to facilitate cellulosic inclusion ?ber length retention. 80 total Weight percent combined With a semi-crystalline The cellulosic inclusions are present in a composition from polyole?n, such as a copolymer of polypropylene, a betWeen 1 and 80 total Weight percent and preferably betWeen homopolymer of polypropylene or a homopolymer of poly 20 and 70 Weight percent, and most preferably betWeen 30 ethylene; and maleic anhydride, and minimal lubrication and 35 and 60 Weight percent of an inventive composition. The cel the addition of polyamide (e.g. polyamide 6 or PA-6), a crys lulosic inclusions are readily dispersed throughout a thermo talline polymer. plastic polyole?n matrix or provided in a graded density One aspect of the present invention is premised on the through coextrusion of varying composition or surface inclusion of a polar thermoplastic resin to a Wood particulate embossment of inclusions. ?lled thermoplastic polyole?n. While maleic anhydride 40 The thermoplastic polyole?n that forms the matrix in grafted polypropylene is a conventional addition to improve Which the cellulosic inclusions and other inventive composi strength in WPCs, it has been surprisingly discovered that the tion components are dispersed illustratively includes polyeth addition of the polar thermoplastic resin operates synergisti ylene, polypropylene, of propylene and ethylene, cally With the maleic anhydride grafted polypropylene to and mixtures of polypropylene and . Preferably, further improve the properties of an article formed from the 45 the polyole?n is polypropylene and more preferably a composition. The present invention also operates With a vari copolymer of propylene and ethylene. The thermoplastic ety of maleated polymers to improve article properties rela polyole?n according to the present invention has a melt ?oW tive to conventional WPCs. index of betWeen 1-100 dg per minute and more preferably As used herein, “total Weight percent” With respect to an betWeen 20 and 80 dg per minute and most preferably a melt inventive cellulosic inclusion-thermoplastic composition is 50 ?oW index of betWeen 30 and 50 dg per minute. A thermo inclusive of a thermoplastic polyole?n matrix material, cel plastic polyole?n is typically present from 30 to 75 total lulosic inclusions, a maleated polymer, a polar thermoplastic Weight percent of an inventive composition and preferably polymer resin of polyamide or a polyester and conventional from 35 to 60 total Weight percent. It is appreciated that the additives thereto such as pigments, colors, bloWing agents, thermoplastic polyole?n need not be a virgin polyole?n and lubricants and . Total Weight percent as used 55 instead can include recycled polyole?ns including those that herein speci?cally excludes noncellulosic reinforcements or are ?lled or reinforced With ?brous inclusions. In this Way ?llers. thermoplastic material that Would otherWise be discarded in a An inventive composition includes a plurality of cellulosic land?ll or incinerated is recycled into a molded article using inclusions dispersed in a thermoplastic polyole?n matrix. A an inventive composition. Preferably, the thermoplastic poly maleated polymer is present along With a polar thermoplastic 60 ole?n has a melting temperature betWeen 150 and 2000 Cel polymer resin of a polyamide or a polyester so as to increase sius and more preferably betWeen 155 and 175° Celsius. interaction betWeen the cellulosic inclusions and the matrix A maleated polymer is present in an inventive composition as evidenced by an increased break tensile strength relative to and is characterized by a graft polymer in Which maleic a composition devoid of the resin. anhydride is graft copolymeriZed With a polymer. Maleated Cellulo sic inclusions operative herein illustratively include 65 polymers operative in the present invention illustratively jute, sWitch grass, Wheat straW, bamboo, Wood, cotton, ?ax include a maleic anhydride grafted copolymer of polypropy ?ber, rice hulls, and combinations thereof. Cellulosic ?bers lene, maleated polyethylene, maleated copolymers or ter US 8,546,470 B2 7 8 polymers of propylene containing acrylate and maleate, aramid, PET polyester, viscose and ceramic. Rubber modi maleic anhydride grafted , and combinations ?ed illustratively including rubbers of ethyl thereof. Preferably, the degree of maleation is betWeen 0.1 ene butene, ethylene octene, styrene butadiene, EPDM, latex, and 5 maleic anhydride content as Weight percent of the and saturated styrenic block copolymer (SEBS). Typically, a maleated polymer. Preferably, the degree of maleation is noncellulo sic inclusion ?ller or reinforcement is present in an between 1 and 4 Weight percent of the maleated polymer and amount of betWeen 0 and 20 parts by Weight per part by most preferably between 1 and 2 Weight percent. Typically, a Weight of thermoplastic polyole?n. maleated polymer is present in an inventive formulation in an To facilitate compounding of cellulosic inclusion thermo amount of betWeen 0.1 and 10 total Weight percent and pref plastic composition With other types of ?ller or ?ber rein erably between 1 and 5 total Weight percent. forcements, all of the components are compounded together, A polar thermoplastic polymer resin of a polyamide or polyester is also provided. The thermoplastic polar polymer or alternatively a cellulosic inclusion thermoplastic inventive composition is formed into pellets that are blended With non resin is either aliphatic, aromatic, or a combination thereof. Speci?c polar thermoplastic polymer resins operative herein cellulosic inclusion ?lled or ?ber reinforced polyole?nic pel include polyamide-6, polyamide-66, polyamide-6-l0, polya lets. It is appreciated that cellulosic inclusion ?lled pellets and mide-46, polyphthalamide, polyethylene terephthalate (PET) noncellulosic ?lled pellets should be roughly melt tempera polyester, and polycaprolactones. Preferably, the polar ther ture matched as to the polyole?n matrix to facilitate ef?cient moplastic polymer resin is selected to have a melting tem formation of a hybrid extrudate. perature greater than the melting temperature of the thermo Highly loaded Wood ?ber-reinforced polyole?n pellets plastic polyole?n making up the bulk of the matrix in Which 20 may be mixed With pellets of a virgin and or recycled poly the cellulosic inclusions are dispersed. The polar thermoplas ole?n and or pre-compounded glass ?ber reinforced and or tic polymer resin has a melt ?oW index of between 1 and 100 mineral and fed to an injection molding machine or other dg per minute and preferably between 10 and 70 dg per types of molten forming equipment to make plasticiZed minute and most preferably betWeen 20 and 40 dg per minute. hybrid blends to suit a variety of end-use molding applica Preferably, the polar thermoplastic polymer resin is selected 25 tions. An injection molding machine or any type of plasticat to have a melting temperature greater than the melting tem ing extruder, provides the necessary mixing and ?ber disper perature of the thermoplastic polyole?n making up the bulk of sion to combine unlike ?ber reinforcement that have an the matrix in Which the cellulosic inclusions are dispersed. admixture of high shear and loW shear material properties. Without intending to be bound to a particular theory, it is The ?exibility of varying the blend ratio of Wood plastic believed that the maleated polymer and the polar thermoplas 30 compounded pellet and other types of ?ber reinforced poly tic polymer resin chemically interact during processing to ole?n pellets, i.e. glass, jute, hemp, sisal is advantageous to create polar thermoplastic polymer resin side chains extend the end-user. This provides the fabricator With a Wide spec ing from the maleated polymer that enhances interaction and trum of end-use properties Without the need for doing sepa dispersion in the base thermoplastic polyole?n and enhanced rate compounding extrusion of composites of speci?c com interaction With the cellulosic inclusions.As the subsequently 35 position. detailed examples provide, enhanced thermal, mechanical An injection molding machine or any type of plasticating and structural properties obtained in the resultant article extruder provides the necessary mixing and ?ber dispersion include increased break tensile strength as measured at 23° to combine unlike ?ber reinforcement that have high shear Celsius and a cross-head speed of 50 millimeters per minute and loW shear properties. The ?exibility of varying the blend relative to a comparable composition lacking the polar ther 40 ratio of inventive composition pellets and other types of ?lled moplastic polymer resin. Surprisingly, the processability of or ?ber reinforced polyole?n pellets is advantageous to the the polar thermoplastic resin is increased through incorpora end user. This provides the fabricator With a Wide spectrum of tion into an inventive composition and polar thermoplastic end-use properties Without the need for doing separate com polymer resin processing at temperatures beloW the conven pounding extrusion of composites of speci?c composition. tional processing WindoW for a particular polymer are noted. 45 An inventive composition is readily melt blended and Additional additives common to the industry are readily extruded With a different composition pellet in a process accommodated by an inventive formulation With these addi commonly referred to as “compounding”. Blending and tives typically including pigments, colors, chemical or gas extruding is readily achieved using a tWin screW extruder to bloWing agents, lubricants, thermal stabiliZers, oxidation sta mix, melt andblend the materialsithis process is also used to biliZers, and plasticiZers, With each of the additives being 50 simultaneously remove any moisture from the materiali present in amounts typically ranging from 0.1 to 5 total delivering an essentially “dry” extrudate Which may be cut to Weight percent for each. form pellets. It is appreciated that an inventive composition These Wood plastic compounded pellets, When combined containing only cellulosic inclusion and absent other ?llers or and/or dry blended With a ?lled or compounded polyole?n ?ber reinforcement is also provided. pellet containing other natural ?bers, glass ?bers, minerals, 55 The present invention is further detailed in the folloWing lubrication, ?ame retardants, pigments and subsequently pro nonlimiting examples. These examples are not intended to cessed to make a Wide variety of end-use composite. The limit the scope of the appended claims to those speci?c for Wood plastic compounded pellets and glass ?ber reinforced mulations or results provided in these examples. polypropylene pellets that are dry blended at the injection molded machine create a superior Wood plastic compounded 60 EXAMPLE 1 hybrid product that duplicate the ?exural strength of dry Wood of 1,000,000 psi. The compounding extrusion of the Wood plastic composite Noncellulosic ?llers and reinforcements are also option concentrate pellets Was accomplished by using a 90 mm co ally provided hereWith and illustratively include rubber modi rotating-intermeshing tWin screW extruder having eight ?ed polypropylene; mineral ?llers such as talc, calcium car 65 heated Zones along a 40 L/ D barrel. The elevated barrel tem bonate, mica, Wollastonite, magnesium oxide, kaolin, perature settings in the ?rst three Zones (4800 F.) insure 100% nanoclay; noncellulosic ?bers such as ?bers of glass, carbon, softening of the PA-6 pellets. In spite of compounding at US 8,546,470 B2 1 0 barrel jackets set as such elevated temperatures, there Was no MD 353. The fourth pellet consisted of a black pigmented indication of the Wood ?ber degradation. Nylon 66 pellet produced by Clariant. These pellets Would be Polypropylene and other pelletiZed ingredients (MAPP dry blended for 100 lbs. batch. The batch Would then be and PA-6) Were metered to the main feed port by an array of vacuumed to the hopper to load the injection molding gravimetric feeders. The Wood ?our, that initially had 6-8 Wt machine for extruding. The batch blend consisted of 73% Water content, Was fed directly to the extruder at a side feeder Wood concentrate, 24% Exxon Mobil copolymer, and 3% located downstream. A lubricant Was also fed into the Clariant Nylon 66 black pigment. The injection molder had a extruder. An atmospheric vent located just up stream of Wood single screW extruder With a 20;1 L/ D and a barrier screW for addition alloWed for initial ?ashing of 2-3 Wt % of Water transporting blend. The barrel pro?le Was set at 400° F. in the vapor. The disengagement and removal of the remainder of throat of the machine and 380° F. in the last Zone. The tool had the Water content occurred at the doWnstream vacuum port one cavity that had a temperature of 80° F. equipped With a vent stuffer to prevent entrainment of molten The injection molder Was con?gured With gas assist to mass into the line to the vacuum pump. The discharge screWs pressuriZe the Wood plastic composite extrudate. The gas of the tWin screW pumped the devolatiliZed WPC melt into a assist ?uid Was nitrogen. The nitrogen gas mixed With the multi-hole die of the Gala underWater pelletiZer having a Wood plastic composite extrudate and compressed Wood ?our rotating cutter blade arrangement to produce WPC concen so that the Walls of the molded article Were solid in some areas trate pellets. and had small voids in other. More so, the nitrogen gas pres By operating at an high ?oW per die hole having a su?i sure closest to the injection point of the gate had no visible ciently large die hole diameter, Wood plastic compounded voids and to the extreme locations of the part aWay from the pellets that Were produced that retained an effective amount 20 gas pressure there Were voids. of sensible heat to promote ?ashing of entrained moisture off the pellet surface upon exiting the centrifugal dryer. Further EXAMPLE 4 more, by a combination of high extrudate velocities out of the die holes and compressive forces due to die pressures of Table 1 provides the formulations for a comparative com 700-800 psi, the resulting pellets Were compress having a 25 position I lacking a polar polymer resin ingredient and an density (>0.9 g/cc) due to a loW degree of porosity. inventive composition A that is otherWise the same yet con As a consequence of the dynamic nature of the physical tains 3 total Wt % polyamide but otherWise the same, and both forces imposed on the melt extruder in the die holes, the Wood having cellulosic inclusion of 58 total Wt %, and 2 total Wt % plastic compounded pellets Were covered by a polymer skin maleic anhydride grafted polypropylene (MAPP) pellets. that functioned as a barrier layer that hindered absorption of 30 The compounding extrusion of composition pellets is residual surface Water during the ?ash evaporation process accomplished by using a 50 mm co-rotating-intermeshing along the Witte shaker table. The pellets had a loW moisture tWin screW extruder having eight heated Zones along a 40 L/D content, eg <1 Wt % moisture content. Besides the physical barrel. Polypropylene and other pelletiZed ingredients forces responsible for the formation of the outer skin, the (MAPP and polyamide-6) are metered to the main feed port polymeric skin is held tenaciously to the interior Wood struc 35 by an array of gravimetric feeders. The undried Wood ?our, ture by strong adhesive forces. This interfacial adhesion Was that initially had 6-8 Wt % Water content, is fed directly to the veri?ed by pressing out Wood plastic compounded pellets extruder at a side feeder located doWnstream. A separate betWeen polyester ?lms in a Carver Press. feed-stream of lubricant is also fed along With the Wood ?our to the side feeder to avoid any interference in the melting of EXAMPLE 2 40 the polyamide-6 in the upstream mixing Zones. An atmo spheric vent located just upstream of Wood addition alloWs The Wood plastic compounded pellets Were dried for a for initial ?ashing of 2-3 Wt % of Water vapor. The disengage period of 4 hours to less than 1% percent moisture. These ment and removal of the remainder of the Water content pellets Were blended With pelletiZed 20 Wt % glass ?ber occurs at the doWnstream vacuum port equipped With a vent reinforced polypropylene copolymer at a 75:25 Wt % blend 45 stuffer to prevent entrainment of molten mass into the line to ratio. The Wood plastic compound hybrid compositions Were the vacuum pump. The discharge screWs of the tWin screW then injection molded. pump the devolatiliZed melt into a multi-hole die of the Gala The barrel cylinder temperature settings of the injection underWater pelletiZer having a rotating cutter blade arrange molding press Were 390° E. (Zone 1), 380° E. (Zone 2) and ment to produce composition pellets. 370° E. (Zone 3) With the noZZle temperature set at 375° F. and 50 a mold temperature setting of 140° F. for both hybrid blends. TABLE 1 EXAMPLE 3 Composition of Wood-Polypropylene Concentrate Pellets Comp arative An injection molder, having a single screW extruder, Was 55 Composition I (total Inventive Composition charged With four pelletiZed materials. The ?rst pellets Were Ingredients Wt %) A (total Wt %) a Wood composite compounded concentrate produced by 45 dg per min. melt ?oW rate 39.5 36.5 MGP Ingredients. These compounded pellets Would be dried polypropylene copolymer for 8 hrs., prior to blending With other pellets, to reduce the MAPP 2.0 2.0 moisture level of the pellets to essentially Zero moisture. 60 Polyamide-6 i 3.0 These Wood concentrate pellets Were identi?ed as a 60/40 Pine Wood ?our: 40-60 mesh 58.0 58.0 compounded blend. The 60 Was actually 58% Wood ?our by Lubricant 0.5 0.5 Weight and the 40 Was a polypropylene by Weight. The 2 percent, not mentioned in the 60/40 compounded blend, Was From each of the comparative composition I and the inven a coupling agent for Wood ?our and polypropylene. The sec 65 tive compositionA that contains polyamide-6 but is otherWise ond pellet Was an Exxon Mobile PP 7684KN a copolymer. identical to the comparative, duplicate test bars Were pro The third pellet Was a Fusabond coupling agent, a Dupond duced to alloW for measurement of tensile strength (FIG. 1A), US 8,546,470 B2 11 12 ?exural strength yield (FIG. 2A), and ?exural modulus-chord grafted polystyrene present at 3 total Weight percent and (FIG. 3A) for the compositions of Table 1. As noted for each containing 2 percent maleic anhydride content based on the of the ?ve test values taken for each composition, the inven grafted polystyrene polymer Weight. The inventive composi tive composition containing the polar thermoplastic polymer tion also contains 3 total Weight percent PET polyester having resin had dramatically improved physical properties in all a melt ?oW index of 37 dg per minute. Resultant injection three tests. molded test bars shoWs improved tensile, ?exural, and notched IZOD performance for the inventive composition EXAMPLE 5 relative to comparative composition C.

Compositions corresponding to those produced in EXAMPLE 8 Example 4 are provided With the exception that the amount of maleated polypropylene Was reduced to 1.5 total Weight per Pre-dried pellets are prepared according to the inventive cent and the amount of polyamide-6 Was reduced from 3 to 2.25 percent relative to inventive composition WPC-G. Five composition of Table 1 With the exception that the levels of duplicate samples for these compositions and observed cellulosic inclusions, maleated polymer and polyamide-6 are increase in all three mechanical properties Were still observed varied. The pellets are mixed With either glass ?ber reinforced relative to the comparative example containing 1.5 Weight composite pellets (Inventive B) or just neat polypropylene percent maleated polypropylene as Well as compared to copolymer resin pellets (Inventive C) to yield a set of blend WPC-C. ratios folloWed by injection molding to make ISO test speci mens. The molded test samples have a MAPP present at 2 Wt EXAMPLE 6 20 % and polyamide-6 present at 3 Wt %. FIGS. 1B, 2B, 3B and 4 shoW linear or parabolic trend-line plots for the resulting Comparative composition II and inventive composition B melt ?oW rate and mechanical properties of the molded (2% MAPP (2% maleic anhydride content) and 3 Wt % polya hybrid blends. These plots represent the potential for making mide-6 are post-dried in a hot air oven set at 108°-120o C. for a Wide spectrum of molded products With an inventive com a period of 4 hours prior to blending With pelletiZed 20 Wt % 25 position ranging from 1 to 100 Wt %. Comparative prior art glass ?ber reinforced polypropylene copolymer at a 75 :25 Wt data is also provided. % blend ratio. The compositions are then molded using an Patent documents and publications mentioned in the speci injection molding press into a set of ISO tensile bars that Were ?cation are indicative of the levels of those skilled in the art to used to make test specimens for tensile, ?exural, notched Which the invention pertains. These documents and publica IZOD, HDT and ISO plaques for shrinkage measurements. In tions are incorporated herein by reference to the same extent addition, ?ller content and melt ?oW rate Were determined 30 With cut pieces of the tensile bars. as if each individual document or publication Was speci?cally By molding at temperatures beloW the thermal decompo and individually incorporated herein by reference. sition temperature of Wood (<392o E), the second heating The foregoing description is illustrative of particular history for the Wood constituent in the inventive concentrate embodiments of the invention, but is not meant to be a limi pellets has greatly reduced tendency for burning in the mold. 35 tation upon the practice thereof. The folloWing claims, The resulting physical properties are listed in Table 2. The including all equivalents thereof, are intended to de?ne the hybrid blend of inventive pellet composition B With glass scope of the invention. ?ber has much greater tensile strength, ?exural strength and The invention claimed is: ?exural modulus than the hybrid blend of comparative II 1. A cellulosic inclusion-thermoplastic composition com lacking the polyamide-6 constituent. 40 prising: a plurality of cellulosic inclusions comprising cellulosic TABLE 2 a thermoplastic polyole?n having a thermoplastic polyole Mechanical Properties of In'ection Molded Hybrid Blends ?n melting temperature and forming a matrix in Which 45 said plurality of cellulosic inclusions are dispersed, the Hybrid Blend Properties: 75 Wt % cellulosic-polyole?n Pellets + thermoplastic polyole?n being selected from the group 25 Wt % GFR Comparative Inventive consisting of: polypropylene, a copolymer of propylene PP Pellets II B and ethylene, a mixture of polypropylene and polyeth ylene; WPC compatabilizer package 2 Wt % MAPP 2 Wt % MAPP 0 Wt % PA-6 3 Wt % PA-6 50 a maleated polymer present at a maleated polymer total Melt flow rate, dg/rnin 8.2 6.3 Weight percent; and content, Wt % 5.6 5.8 a polar thermoplastic polymer resin of a polyamide or a Density gcc 1.095 1.096 polyester, said polar thermoplastic resin having a resin Tensile strength-break, psi @ 50 mrn/min 5,554 6,902 Tensile elongation-Bk, % 0.8 1.2 melting temperature and present at polar polymer total Flexural strength-yield, psi @ 2 mrn/min 9,993 11,136 Weight percent, said maleated polymer and said polar Flexural modulus-chord, psi 790,250 825,050 thermoplastic resin interacting synergistically betWeen Notched IZOD impact, ?-lb/in 0.58 0.65 said plurality of cellulosic inclusions such that the com HDT-0.45 MPa (0 F.) 311 313 HDT-1.8 MPa (0 F.) 257 261 position has an increased break tensile strength as mea Hardness 67 66 sured at 23° Celsius and at an cross-head speed of 50 Mold shrinkage-ISO plaque after 48 hrs 0.65/0.93 0.67/0.74 60 millimeters per minute relative to a composition devoid conditioning MD/TD % of said resin, Wherein the maleated polymer total Weight percent is present betWeen 1 to 5 total Weight percent and the polar polymer total Weight percent is present EXAMPLE 7 betWeen 1 and 10 total Weight percent, and said plurality 65 of cellulosic inclusions has a moisture content of less The process of Example 6 is repeated With comparative than 10 Weight percent of said plurality of cellulosic composition containing a terpolymer of maleic anhydride inclusions. US 8,546,470 B2 13 14 2. The composition of claim 1, wherein said polyole?n is 12. The composition of claim 8 further comprising a min said mixture of polypropylene and polyethylene. eral or inorganic ?ller or ?brous reinforcement. 3. The composition of claim 1, Wherein said polar thermo 13. The composition of claim 8 Wherein said plurality of plastic polymer resin is said polyamide. cellulosic inclusions are at least one of: jute, sWitch grass, 4. The composition of claim 1 Wherein the resin melting Wheat straW, bamboo, Wood, cotton, ?ax ?ber, rice hulls, or temperature is greater than the thermoplastic polyole?n melt combinations thereof. ing temperature. 14. The composition of claim 8 Wherein said polar thermo 5. The composition of claim 1 Wherein said plurality of plastic polymer resin is said polyamide and is one of: polya cellulosic inclusions comprise Wood ?our. mide-6, polyamide-66, polyamide-6-l0, polyamide-46, or 6. The composition of claim 1 further comprising a mineral polyphthalamide. or inorganic ?ller or ?brous reinforcement. 15. The composition of claim 8 further comprising a bloW 7. The composition of claim 1 further comprising a bloW ing agent. ing agent. 8. A cellulosic inclusion-thermoplastic composition com 16. A method of making the composition of claim 8 com prising: prising: a plurality of cellulosic inclusions; blending a thermoplastic ole?n, a plurality of cellulosic a thermoplastic polyole?n having a thermoplastic polyole inclusions, a maleated polymer, and polar thermoplastic ?n melting temperature and forming a matrix in Which resin of a polyamide or a polyester to form a blend; and said plurality of cellulosic inclusions are dispersed, the forming said blend to form a solid article in Which said thermoplastic polyole?n being selected from the group 20 maleated polymer and said polar resin interact synergis consisting of: polypropylene, a copolymer of propylene tically to promote adhesion betWeen said plurality of and ethylene, a mixture of polypropylene and polyeth cellulosic inclusions and said thermoplastic ole?n as ylene; noted by an increased break tensile strength as measured a maleated polymer present at a maleated polymer total at 230 Celsius and at an cross-head speed of 50 millime Weight percent; and 25 ters per minute relative to a composition devoid of said a polar thermoplastic polymer resin of a polyamide or a resin. polyester, said polar thermoplastic resin having a resin 17. The method of claim 16 Wherein the blending is melt melting temperature and present at polar polymer total blending and the forming is by extruding. Weight percent, said maleated polymer and said polar 18. The method of claim 17 Wherein melt blending is at or thermoplastic resin being dispersed and interacting syn 30 beloW a temperature that is a melting point of said polar ergistically to promote adhesion betWeen said plurality thermoplastic resin. of cellulosic inclusions such that the composition has an 19. The method of claim 16 further comprising drying said increased break tensile strength as measured at 230 Cel plurality of cellulosic inclusions prior to the blending. sius and at an cross-head speed of 50 millimeters per 20. The method of claim 16 Wherein said article is an minute relative to a composition devoid of said resin, 35 Wherein the maleated polymer total Weight percent is injection moldable pellet. present betWeen 2 to 4 total Weight percent and the polar 21. The method of claim 20 further comprising melt blend polymer total Weight percent is present betWeen 2 and 4 ing said pellet With a secondary thermoplastic ole?n. total Weight percent, and said plurality of cellulosic 22. The method of claim 21 Wherein said secondary ther moplastic ole?n is a virgin polyole?n, a recycled polyole?n, inclusions has a moisture content of less than 10 Weight 40 percent of said plurality of cellulosic inclusions. a ?lled polyole?n, or a ?ber-reinforced polyole?n. 9. The composition of claim 8, Wherein said polar thermo 23. The method of claim 22 Wherein said ?lled polyole?n plastic polymer resin is said polyamide. or said ?ber-reinforced polyole?n comprises a ?ller or ?ber of 10. The composition of claim 8 Wherein the resin melting mineral particulate, noncellulosic ?bers, and noncellulosic rubbers. temperature is greater than the thermoplastic polyole?n melt 45 ing temperature. 24. The method of claim 21 Wherein said secondary ther 11. The composition of claim 8 Wherein said plurality of moplastic ole?n is polypropylene. cellulosic inclusions comprise Wood ?our. * * * * *