Polydiorganosiloxane compositions and methods of using the same in forming wood-plastic composites

Abstract

A polydiorganosiloxane can be used in a composition and method for preparing a wood-plastic composite product. The wood-plastic composite product can be used as a building material. The polydiorganosiloxane can be added to the composition in liquid form or can form part of a solid carrier component used to prepare the wood-plastic composite product.

Description

[0001] This application is a divisional application of the invention patent application with an international filing date of June 10, 2020, international application number PCT / US2020 / 036891, application number 202080054897.X entering the Chinese national phase, and invention name “Polydiorganosiloxane composition and its use method in forming wood-plastic composite materials”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims the benefit under 35 USC §119(e) of U.S. Provisional Patent Application No. 62 / 883,683, filed on August 7, 2019. U.S. Provisional Patent Application No. 62 / 883,683 is hereby incorporated by reference. Technical Field

[0004] Polydiorganosiloxanes can be used in wood plastic composite (WPC) compositions and methods for making WPC articles.The polydiorganosiloxanes can be delivered in liquid or solid form. Background Art

[0005] Conventional processes for preparing WPC products typically require processing aids (which may be internal or external) to facilitate forming and ensure the quality of the WPC products (e.g., smoothness of the surface and edges). Conventional low-cost organic processing aids typically suffer from the disadvantage of requiring high loadings to achieve faster production speeds, thereby affecting cost and / or performance. In addition, many conventional processing aids may adversely affect the physical properties of the WPC products and reduce mechanical properties (such as impact resistance, flexural strength, and flexural modulus), especially at high use temperatures. Conventional processing aids may also migrate from the WPC products, thereby adversely affecting one or more properties of the WPC products over time, such as physical properties, appearance, feel, ability to overmold, ability to coextrude, ability to adhere to a surface, ability to print on a surface, or ability to paint the surface of the WPC products. In addition, some organic processing aids volatilize at higher application temperatures, which may lead to bubbles and cracks in the forming of the WPC products or in the WPC products, which may impair the long-term performance of these products. Summary of the Invention

[0006] A composition comprising: (a) a lignocellulose-based filler; (b) a vinyl polymer; and (c) a polydiorganosiloxane, wherein each R is an independently selected monovalent hydrocarbon group having 1 to 18 carbon atoms and free of aliphatic unsaturation, and the subscript x has a sufficient value to provide the polydiorganosiloxane with a viscosity of >350 mPa·s to 100,000 mPa·s as measured at 25° C. on a Brookfield DV-III cone and plate viscometer with a #CP-52 spindle at 0.1 to 50 RPM. A method for preparing a wood-plastic composite article from the composition is also disclosed.

[0007] A solid support component comprises:

[0008] (i) the polydiorganosiloxane described above as starting material (c); and

[0009] (ii) a polymer component selected from the group consisting of:

[0010] vinyl polymers,

[0011] Maleated vinyl polymers, and

[0012] A combination of both vinyl polymers and maleated vinyl polymers.A solid carrier component may be used to deliver the polydiorganosiloxane to the composition. DETAILED DESCRIPTION

[0013] The composition can be used to prepare wood-plastic composite products. The composition comprises:

[0014] 15 to 70 wt% of (a) a lignocellulose-based filler;

[0015] 29.5 to 84.5 weight percent of (b) a vinyl polymer;

[0016] 0.5 wt% to 6 wt% of a compound having the formula (c) a polydiorganosiloxane wherein each R is an independently selected monovalent hydrocarbon group having 1 to 18 carbon atoms free of aliphatic unsaturation, and the subscript x is sufficient for the polydiorganosiloxane to have a viscosity of from >350 mPa·s to 100,000 mPa·s as measured at 25°C on a Brookfield DV-III cone and plate viscometer with a #CP-52 spindle at 0.1 to 50 RPM; and

[0017] 0 to 4 wt% of (d) a maleated vinyl polymer;

[0018] Each is based on the combined weight of starting materials (a), (b), (c) and (d) in the composition.

[0019] (a) Lignocellulose-based fillers

[0020] Above-mentioned composition comprises starting material (a) lignocellulose-based filler.Lignocellulose-based filler comprises lignocellulose material, alternatively is basically composed of lignocellulose material, alternatively is composed of lignocellulose material.Usually, lignocellulose-based filler is composed of lignocellulose material.Lignocellulose-based filler and lignocellulose material can comprise any substance deriving from any plant source.When lignocellulose-based filler is basically composed of lignocellulose material or is composed of lignocellulose material, lignocellulose material also can comprise some water or moisture content, although lignocellulose material and lignocellulose-based filler are usually dry, i.e. do not comprise any free moisture content, but may be relevant with the relative humidity in the environment of preparation, derivation, formation and / or storage lignocellulose-based filler.For other kinds of (a) lignocellulose-based filler, usually the situation is also the same, but for lignocellulose-based filler, note that lignocellulose material is usually included in some water content gathered in the crops / preparation before any drying or final use.

[0021] Lignocellulose-based fillers generally comprise carbohydrate polymers (such as cellulose and or hemicellulose), and can also comprise aromatic polymers (such as lignin).Lignocellulose-based fillers are generally natural lignocellulose materials, that is, not synthetically derived.For example, lignocellulose-based fillers derive from timber (hardwood, softwood and / or plywood) generally.Alternatively or in addition, lignocellulose-based fillers can comprise the lignocellulose materials from other non-wood sources, such as the lignocellulose materials from plant, or the polymers of other plant origins, such as agricultural byproducts, husks, sisal, bagasse, wheat straw, kapok, ramie, gray leaf sisal, corn fiber or coconut shell, nut shell, flax, jute, hemp, kenaf, rice husk, Manila hemp, peanut shell, bamboo, straw, lignin, starch or cellulose and cellulose-containing product and their combination.Lignocellulose-based fillers can be primary, recovery or their combination.

[0022] Alternatively, the lignocellulose-based filler may comprise a wood filler. "Wood" is as described in Pettersen, Roger C., US Department of Agriculture, Forest Service, Forest Products Laboratory, Madison, WI, The Chemical Composition of Wood, Chapter 2. Wood may contain lignin in an amount of 18% to 35% and carbohydrates in an amount of 65% to 75% and optional inorganic minerals in an amount of up to 10%. The carbohydrate portion of the wood comprises cellulose and hemicellulose. The cellulose content may be in the range of 40% to 50% of the dry weight of the wood, and the hemicellulose content may be in the range of 25% to 35%. Based on the dry weight of the wood filler, the alpha-cellulose content may be 29% to 57%, alternatively 40% to 50%. The wood filler is derived from wood, for example, hardwood and / or softwood. The specific example of the suitable hardwood that can be derived from wood filler includes but is not limited to ash, poplar, cottonwood, basswood, birch, beech, chestnut, rubber tree, elm, eucalyptus, maple, oak, poplar, sycamore and their combination. The specific example of the suitable softwood that can be derived from wood filler includes but is not limited to spruce, fir, hemlock, tamarisk, larch, pine, cypress, redwood and their combination. The filler deriving from the combination of different hardwoods, the combination of different softwoods or the combination of hardwood and softwood can be used as wood filler together. Alternatively, lignocellulose-based filler can be basically composed of wood filler. Alternatively, lignocellulose-based filler can be composed of wood filler.

[0023] Lignocellulose-based fillers can have any form and size, for example nanometer to millimeter particle size. For example, lignocellulose-based fillers can include powder, pulp, flour, sawdust, fiber, flakes, fragments, shavings, strands, scrim, pancake, wool, straw, particles or any combination thereof. Lignocellulose-based fillers can be formed via a variety of techniques known to those skilled in the art, usually formed according to their form. For example, lignocellulose-based fillers can be prepared by crushing logs, branches, industrial wood residues or coarse wood pulp. Lignocellulose-based fillers can be crushed to desired particle size. For example, lignocellulose-based fillers can be crushed with any convenient equipment such as a hammer mill, which causes the lignocellulose-based filler to have a particle size suitable for mixing processes. The desired particle size is usually selected by those skilled in the art based on the desired characteristics of the specific mixing method used and the wood-plastic composite material product. So-called particle size means the size of the lignocellulose-based filler, no matter how the shape is, and includes, for example, the size associated with the lignocellulose-based filler when it is in fiber form. As is known in the art, the lignocellulose-based filler may be pelletized, or otherwise in the form of a granule, which may substantially maintain shape and size when incorporated into the composition, or it may form smaller particles in the composition.

[0024] The shape and size of the lignocellulose-based filler are also not particularly limited. For example, the lignocellulose-based filler can be spherical, rectangular, oval, irregularly shaped, and can be in the form of, for example, powder, flour, fiber, flakes, chips, shavings, strands, scrim, wafers, wool, straw, granules, and combinations thereof. The size and shape are generally selected based on the type of lignocellulose-based filler used, the selection of other starting materials included in the WPC composition, and the end-use application of the WPC article formed therefrom.

[0025] The starting material (a) may be a lignocellulose-based filler or may be a combination of two or more lignocellulose-based polymers that differ from each other in at least one property, such as the plant source from which the lignocellulose-based filler is derived, the lignin content, the α-cellulose content, the preparation method, the filler shape, the filler surface area, the average particle size and / or the particle size distribution. The starting material (a) may be present in the composition in an amount of 15% to 70%, alternatively 45% to 65%, based on the combined weight of the starting materials (a), (b), (c) and (d).

[0026] (b) Vinyl polymers

[0027] The above composition also includes a starting material (b) vinyl polymer. As used herein, a "vinyl" polymer is a polymer prepared from vinyl monomer as the main (i.e., greater than 50%) monomer component, but other comonomers may also be used. "Polymer" means a macromolecular compound prepared by reacting (i.e., polymerizing) monomers of the same or different types, and includes homopolymers and interpolymers. "Interpolymer" means a polymer prepared by polymerization of at least two different monomer types. This general term includes copolymers (usually used to refer to polymers prepared from two different monomer types) and polymers prepared from two or more different monomer types (e.g., terpolymers (three different monomer types) and tetrapolymers (four different monomer types)).

[0028] The ethylene-based polymer may be an ethylene homopolymer. As used herein, "homopolymer" means a polymer comprising repeating units derived from a single monomer type, but does not exclude residual amounts of other components used to prepare the homopolymer, such as catalysts, initiators, solvents, and chain transfer agents.

[0029] Alternatively, the ethylene-based polymer may be an ethylene / α-olefin ("α-olefin") interpolymer having an α-olefin content of at least 1%, alternatively at least 5%, alternatively at least 10%, alternatively at least 15%, alternatively at least 20%, or alternatively at least 25%, by weight, based on the weight of the entire interpolymer. These interpolymers may have an α-olefin content of less than 50%, alternatively less than 45%, alternatively less than 40%, or alternatively less than 35%, based on the weight of the entire interpolymer. When α-olefins are used, the α-olefins may have from 3 to 20 carbon atoms (C3-C20) and be linear, branched, or cyclic α-olefins. Examples of C3-20 α-olefins include propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-octadecene. The α-olefin may also have a cyclic structure, such as cyclohexane or cyclopentane, resulting in α-olefins such as 3-cyclohexyl-1-propene (allylcyclohexane) and vinylcyclohexane. Exemplary ethylene / α-olefin interpolymers include ethylene / propylene, ethylene / 1-butene, ethylene / 1-hexene, ethylene / 1-octene, ethylene / propylene / 1-octene, ethylene / propylene / 1-butene, and ethylene / 1-butene / 1-octene.

[0030] The starting material (b) can be a single vinyl polymer or a combination of two or more vinyl polymers (e.g., a blend of two or more vinyl polymers that differ from one another in at least one property, such as monomer composition, monomer content, catalytic method of preparation, molecular weight, molecular weight distribution, and / or density). If a blend of vinyl polymers is employed, the polymers can be blended by any in-reactor or post-reactor method.

[0031] The vinyl polymer used for the starting material (b) may be selected from the group consisting of high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), low density low molecular weight polyethylene (LDLMWPE), and combinations thereof.

[0032] Alternatively, the vinyl polymer may be LLDPE. LLDPE is generally a vinyl polymer having an uneven distribution of comonomers (e.g., α-olefin monomers) and is characterized by short chain branching. For example, LLDPE may be a copolymer of ethylene and α-olefin monomers, such as those described above. LLDPE may have a viscosity of 0.91 g / cm 3 to 0.94g / cm 3The density of the LLDPE and other ethylene-based polymers described herein is determined by ASTM D792-13. The LLDPE suitable for use herein may have a melt index (I2) of 1 g / 10 min to 20 g / 10 min, alternatively >2 g / 10 min, alternatively 2.3 g / 10 min to 20 g / 10 min, alternatively 2.3 g / 10 min to 12 g / 10 min, alternatively 2.3 g / 10 min to 6 g / 10 min. The value of I2 for LLDPE and other ethylene-based polymers is determined according to ASTM D1238-13 at 190 ° C and 2.16 Kg. The LLDPE may have a melting temperature of at least 124 ° C, alternatively 124 ° C to 135 ° C, and alternatively 124 ° C to 132 ° C. The melting temperature for LLDPE and other polyethylene-based polymers is determined by DSC according to ASTM D3418-15.

[0033] LLDPE is known in the art and can be produced by known methods. For example, LLDPE can be prepared using a Ziegler-Natta catalyst system and single-site catalysts such as dimetallocenes (sometimes referred to as "m-LLDPE"), post-metallocene catalysts, and constrained geometry catalysts. LLDPE includes linear, substantially linear, or heterogeneous polyethylene copolymers or homopolymers. LLDPE may contain less long-chain branching than LDPE, and LLDPE includes: substantially linear ethylene polymers, which are further defined in U.S. Patent No. 5,272,236, U.S. Patent No. 5,278,272, and U.S. Patent No. 5,582,923; uniformly branched linear ethylene polymer compositions, such as those in U.S. Patent No. 3,645,992; and / or heterogeneously branched ethylene polymers, such as those prepared according to the method disclosed in U.S. Patent No. 4,076,698. LLDPE can be prepared via gas phase, solution phase, or slurry polymerization, or any combination thereof, using any type of reactor or reactor configuration known in the art.

[0034] Alternatively, the vinyl polymer may be MDPE. MDPE is a polymer having a density typically at 0.926 g / cm 3 to 0.940g / cm 3 Alternatively, MDPE may have a density of 0.930 g / cm 3 to 0.939g / cm 3The MDPE may have a density in the range of 0.1 g / 10 min to 20 g / 10 min, alternatively >2 g / 10 min, alternatively 2.3 g / 10 min to 20 g / 10 min, alternatively 2.3 g / 10 min to 12 g / 10 min, and alternatively 2.3 g / 10 min to 6 g / 10 min. The MDPE may have a melting temperature of at least 124° C., alternatively 124° C. to 135° C., and alternatively 124° C. to 132° C. The MDPE may be prepared using chromium or Ziegler-Natta catalysts or using metallocene, constrained geometry, or single-site catalysts, and typically has an MWD greater than 2.5.

[0035] Alternatively, the vinyl polymer may be HDPE. HDPE is a polymer having a viscosity of at least 0.940 g / cm 3 Alternatively, HDPE may have a density of >0.940 g / cm 3 to 0.970g / cm 3 , alternatively >0.940 g / cm 3 to 0.965g / cm 3 , alternatively >0.940 to 0.952 g / cm 3 The HDPE may have a density of at least 124° C., alternatively from 124° C. to 135° C., alternatively from 124° C. to 132° C., and alternatively from 131° C. to 132° C. The HDPE may have an I2 of from 0.1 g / 10 min to 66 g / 10 min, alternatively from 0.2 g / 10 min to 20 g / 10 min, alternatively >2 g / 10 min, alternatively from 2.3 g / 10 min to 20 g / 10 min, alternatively from 3 g / 10 min to 12 g / 10 min, alternatively from 4 g / 10 min to 7 g / 10 min. The HDPE may have a PDI of from 1.0 to 30.0, alternatively from 2.0 to 15.0, as determined by GPC.

[0036] HDPE suitable for use herein may be unimodal. As used herein, "unimodal" means that the HDPE has an MWD such that its GPC curve exhibits only a single peak, without a discernible second peak, or even a shoulder or hump relative to such single peak. In contrast, "bimodal" means that the MWD in the GPC curve indicates the presence of two component polymers, such as by having two peaks, or where one component is indicated by a hump, shoulder, or tail relative to the peak of the other component polymer. The HDPE used herein may be unimodal. HDPE is known in the art and can be prepared by known methods. For example, HDPE can be prepared using Ziegler-Natta catalysts, chromium catalysts, or even metallocene catalysts.

[0037] Alternatively, the vinyl polymer for starting material (b) may be selected from the group consisting of the following items: HDPE, MDPE, LLDPE, and combinations thereof. Alternatively, the vinyl polymer for starting material (b) may be selected from the group consisting of the following items: HDPE, LLDPE, and combinations thereof. Alternatively, the vinyl polymer for starting material (b) may be selected from the group consisting of the following items: HDPE and LLDPE. Alternatively, the vinyl polymer for starting material (b) may be HDPE. Methods for preparing vinyl polymers are well known in the art. Any method for preparing vinyl polymers with desired properties that is known or found below may be used to prepare vinyl polymers. Suitable LLDPE, MDPE, and HDPE may be prepared by the methods described above or those disclosed in PCT Publication No. WO2018 / 049555 and U.S. Patent Application Publication No. 2019 / 0023895 and the references cited therein. Suitable vinyl polymers are commercially available from The Dow Chemical Company, Midland, MI, USA. Examples of suitable vinyl polymers are shown in Table 1 below.

[0038] Table 1 - Vinyl Polymers

[0039]

[0040] The vinyl polymer used in the composition can comprise virgin polymer and / or recycled polymer. Without being bound by theory, it is believed that the vinyl polymer can comprise ≥50% recycled polyethylene. The recycled vinyl polymer, if used, can be derived from industrial process streams, as well as from post-industrial and / or post-consumer sources. The choice of a particular vinyl polymer, and any ratio of virgin polymer to recycled polymer, if used together, generally depends on the cost and desired properties of the WPC article formed therefrom.

[0041] Starting material (b) can be present in the composition in an amount from 29.5% to 84.5%, alternatively from 30% to 60%, alternatively from 35% to 55%, and alternatively from 40% to 50%, based on the combined weight of starting materials (a), (b), (c), and (d).

[0042] (c) Polydiorganosiloxane

[0043] The above composition further comprises a starting material (c) polydiorganosiloxane. The polydiorganosiloxane has the formula wherein each R is an independently selected monovalent hydrocarbon group having 1 to 18 carbon atoms free of aliphatic unsaturation, and the subscript x is sufficient to provide a viscosity of the polydiorganosiloxane of >350 mPa·s to 100,000 mPa·s as measured at 25°C on a Brookfield DV-III cone and plate viscometer with a #CP-52 spindle at 0.1 to 50 RPM. One skilled in the art will recognize that the rotation rate decreases as viscosity increases and will be able to select an appropriate rotation rate when measuring viscosity using this test method. Alternatively, as measured above, the viscosity may be from 1,000 to 50,000 mPa·s, alternatively, from 1,000 to 20,000 mPa·s, and alternatively from 5,000 to 50,000 mPa·s. Alternatively, the viscosity may be 5,000 to 20,000 mPa·s, alternatively 5,000 to 15,000 mPa·s, and alternatively 5,000 to 12,500 mPa·s, as measured at 5 RPM according to the above test method.

[0044] Alternatively, the polydiorganosiloxane may be a trialkylsiloxy-terminated polydialkylsiloxane. Alternatively, each R may be an alkyl group having 1 to 18 carbon atoms, alternatively 1 to 12 carbon atoms, alternatively 1 to 6 carbon atoms, and alternatively 1 to 4 carbon atoms. Suitable alkyl groups include methyl, ethyl, propyl (including n-propyl and isopropyl), butyl (including n-butyl, tert-butyl, sec-butyl, and isobutyl). Alternatively, each R may be methyl.

[0045] Suitable polydiorganosiloxanes can be prepared by methods known in the art, such as hydrolysis and condensation of appropriate organohalosilane monomers and / or equilibration of optionally terminated linear and cyclic polyorganosiloxanes. The polydiorganosiloxane may be a trimethylsiloxy terminated polydimethylsiloxane, which is commercially available. Trimethylsiloxy terminated polydimethylsiloxanes having a viscosity of >350 mPa·s to 100,000 mPa·s are commercially available from Dow Silicones Corporation, Midland, Michigan, USA.

[0046] The starting material (c) can be one polydiorganosiloxane or a combination of two or more polydiorganosiloxanes that differ from one another in at least one characteristic, such as the choice of R group and viscosity. The starting material (c) can be present in the composition in an amount of 0.5% to 6%, alternatively 1% to 4%, alternatively 0.5% to 3%, alternatively 1% to 2%, and alternatively 2% to 4%, based on the combined weight of the starting materials (a), (b), (c), and (d).

[0047] (d) Maleated vinyl polymers

[0048] The above composition may optionally further comprise a starting material (d) maleated vinyl polymer. As used herein, the term "maleated" refers to a polymer (e.g., vinyl polymer) that has been modified to incorporate maleic anhydride monomer. Maleic anhydride can be incorporated into the vinyl polymer by any method known in the art or discovered below. For example, maleic anhydride can be copolymerized with ethylene and other monomers (if present) to prepare an interpolymer having maleic anhydride residues incorporated into the polymer backbone. Alternatively, maleic anhydride can be graft polymerized into the vinyl polymer. Techniques for copolymerization and graft polymerization are known in the art.

[0049] The maleated vinyl polymer may be a vinyl polymer onto which maleic anhydride is grafted. The vinyl polymer prior to maleation may be any of the above-mentioned vinyl polymers. Alternatively, the vinyl polymer used for maleation may have a melt index lower than that of the above-mentioned vinyl polymers. The starting vinyl polymer may be selected from linear low density polyethylene, medium density polyethylene, and high density polyethylene. Alternatively, the starting vinyl polymer may be high density polyethylene.

[0050] The maleated vinyl polymer may have a viscosity of at least 0.923 g / cm 3 Alternatively, the maleated vinyl polymer may have a density of 0.923 g / cm 3 to 0.962g / cm 3 , alternatively 0.940 g / cm 3 to 0.962g / cm 3 and alternatively 0.923 g / cm 3 to 0.940g / cm 3The density of the maleated vinyl polymer may be determined by ASTM D792-13. The maleated vinyl polymer may have an I2 of 0.1 g / 10 min to 25 g / 10 min, alternatively 1 g / 10 min to 2 g / 10 min, alternatively 2 g / 10 min to 25 g / 10 min, alternatively 2 g / 10 min to 12 g / 10 min, alternatively 3 g / 10 min to 25 g / 10 min, and alternatively 3 g / 10 min to 12 g / 10 min. The I2 value of the maleated vinyl polymer is determined according to ASTM D1238-13 at 190° C. and 2.16 Kg. The maleated vinyl polymer may have a maleic anhydride content in an amount of at least 0.25%, alternatively 0.25% to 2.5%, and alternatively 0.5% to 1.5%, each based on the total weight of the maleated vinyl polymer. Maleic anhydride concentration can be measured by titration, and this titration adopts dry resin and uses 0.02N KOH titration to measure the amount of maleic anhydride.By 0.3 gram to 0.5 gram maleated vinyl polymer is dissolved in 150mL refluxing dimethylbenzene and titrates dry polymer.After dissolving completely, deionized water (four drops) is added to the solution, and the solution is refluxed for 1 hour.Next, 1% thymol blue (several drops) is added to the solution, and the ethanolic solution with 0.02N KOH is excessively titrated this solution, as shown in purple formation.Then with the isopropyl alcohol solution of 0.05N HCl, the solution is back titrated to the yellow end point.

[0051] Suitable maleated vinyl polymers for starting material (d) can be prepared by known methods, such as disclosed in PCT publication number WO2018 / 049555 and the references cited therein. Alternatively, maleated vinyl polymers can be prepared by a method for grafting maleic anhydride on vinyl polymers, which can be initiated by decomposing an initiator to form a free radical, wherein the free radical includes azo-containing compounds, carboxyl peroxy acids and peroxy esters, alkyl hydroperoxides and dialkyl and diacyl peroxides, etc. Many of these compounds and their characteristics have been described (reference: J.Branderup, E.Immergut, E.Grulke, ed., "Polymer Handbook" 4th edition, Wiley, New York, 1999, Part II, pp. 1-76). Alternatively, the material formed by initiator decomposition can be an oxygen radical. Alternatively, the initiator can be selected from the group consisting of the following items: carboxyl peroxy esters, peroxy ketals, dialkyl peroxides and diacyl peroxides. Exemplary initiators commonly used to alter polymer structure are listed in the table spanning column 48, line 13 to column 49, line 29 of U.S. Patent No. 7,897,689. Alternatively, the grafting process for preparing the maleated vinyl polymer can be initiated by free radicals generated by a thermal oxidation process. Suitable maleated vinyl polymers are commercially available from The Dow Chemical Company, of Midland, MI, USA, such as those described in Table 2 below.

[0052] Table 2 - Examples of Maleated Vinyl Polymers

[0053]

[0054] In Table 2, the melting temperatures of random ethylene copolymers incorporating monomers classified as maleic anhydride equivalents are measured by DSC according to ASTM D3418-15, and the melting temperatures of high density polyethylene grafted with very high levels of maleic anhydride copolymer grafting are measured by DSC, wherein the film is conditioned at 230° C. for 3 minutes and then cooled at a rate of 10° C. / minute to a temperature of −40° C. After holding the film at −40° C. for 3 minutes, the film is heated to 200° C. at a rate of 10° C. / minute.

[0055] The starting material (d) can be a maleated vinyl polymer or a combination of two or more maleated vinyl polymers (e.g., a blend of two or more maleated vinyl polymers that differ from one another in at least one characteristic, such as monomer composition, monomer content, catalytic method of preparation, molecular weight, molecular weight distribution, and / or density). The maleated vinyl polymer can be present in the composition in an amount of 0% to 4%. Alternatively, the maleated vinyl polymer can be present in an amount of 0% to 2%, alternatively >0% to 2%, alternatively 1% to 3%, and alternatively 1% to 2%, based on the combined weight of the starting materials (a), (b), (c), and (d).

[0056] Additional starting material

[0057] The above composition may optionally further comprise one or more additional starting materials. For example, the one or more additional starting materials may be selected from the group consisting of: (e) an additional filler different from the lignocellulose-based filler of starting material (a), (f) a colorant, (g) a blowing agent, (h) a UV stabilizer, (i) an antioxidant, (j) a processing aid, (k) a preservative, (l) a biocide, (m) a flame retardant, (n) an impact modifier, and (o) a combination of two or more of starting materials (e) to (n). If used, each additional starting material may be present in the composition in an amount greater than 0% to 30% based on the combined weight of all starting materials in the composition. The composition may also comprise other optional additives known in the art. Such additives are described, for example, in Walker, Benjamin M. and Charles P. Rader, eds., Handbook of thermoplastomers. New York: Van Nostrand Reinhold, 1979; Murphy, John, ed., Additives for plastics handbook. Elsevier, 2001.

[0058] (e) Additional fillers

[0059] The composition may also optionally include a starting material (e) filler that is different from the lignocellulosic filler described above as the starting material (a). Specific examples of suitable fillers include, but are not limited to, calcium carbonate, silica, quartz, fused silica, talc, mica, clay, kaolin, wollastonite, feldspar, aluminum hydroxide, carbon black, and graphite. Alternatively, the filler may be a mineral filler. Alternatively, the filler may be selected from the group consisting of calcium carbonate, talc, and combinations thereof. Suitable fillers are known in the art and commercially available, such as ground silica sold by US Silica of Berkeley Springs, West Virginia, USA, under the name MIN-U-SIL. Suitable precipitated calcium carbonate includes Calcium Carbonate® from Solvay. SPM and PTFE from Specialty Minerals, Inc. (Quinnesec, Michigan, USA) and 100.

[0060] The shape and size of the filler are not particularly limited. For example, the filler can be spherical, rectangular, oval, irregularly shaped, and can be in the form of, for example, powder, flour, fiber, flakes, chips, wood shavings, strands, scrim, wafers, wool, straw, particles, and combinations thereof. The size and shape are generally selected based on the type of filler used and the selection of other starting materials included in the solid carrier component.

[0061] Regardless of the choice of filler, the filler may be untreated, pretreated, or added in combination with an optional filler treating agent as described below, in which case the filler may be treated in situ or prior to incorporation into the above-described composition. Alternatively, the filler may be surface treated to facilitate wetting or dispersion in the composition, in which case the filler may be treated in situ in the composition.

[0062] The filler treating agent may include a silane (such as an alkoxysilane), an alkoxy-functional oligosiloxane, a cyclic polyorganosiloxane, a hydroxyl-functional oligosiloxane (such as dimethylsiloxane or methylphenylsiloxane), an organosilicon compound, a stearate, or a fatty acid. The filler treating agent may include a single filler treating agent or a combination of two or more filler treating agents selected from similar or different types of molecules.

[0063] The filler treatment agent may include an alkoxysilane, which may be a monoalkoxysilane, a dialkoxysilane, a trialkoxysilane, or a tetraalkoxysilane. Examples of alkoxysilane filler treatment agents include hexyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, tetradecyltrimethoxysilane, phenyltrimethoxysilane, phenethyltrimethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, and combinations thereof. In certain aspects, alkoxysilanes may be used in combination with silazanes, which can catalyze the reaction of less reactive alkoxysilanes with surface hydroxyl groups. Such reactions are typically conducted at temperatures above 100°C, with high shear, and with the removal of volatile byproducts such as ammonia, methanol, and water.

[0064] Suitable filler treating agents also include alkoxysilyl functionalized alkylmethylpolysiloxanes, or similar materials where the hydrolyzable groups may include, for example, silazane, acyloxy, or oxime groups.

[0065] Alkoxy-functional oligosiloxanes can also be used as filler treatment agents. Alkoxy-functional oligosiloxanes and methods for their preparation are well known in the art. Other filler treatment agents include mono-terminated alkoxy-functional polydiorganosiloxanes, i.e., polyorganosiloxanes having alkoxy functionality at one end.

[0066] Alternatively, the filler treating agent can be any organosilicon compound commonly used to treat silica fillers. Examples of organosilicon compounds include organochlorosilanes such as methyltrichlorosilane, dimethyldichlorosilane, and trimethylmonochlorosilane; organosiloxanes such as hydroxyl-terminated dimethylsiloxane oligomers, silhydride-functionalized siloxanes, hexamethyldisiloxane, and tetramethyldivinyldisiloxane; organosilazanes such as hexamethyldisilazane and hexamethylcyclotrisilazane; and organoalkoxysilanes such as alkylalkoxysilanes having methyl, propyl, n-butyl, isobutyl, n-hexyl, n-octyl, isooctyl, n-decyl, dodecyl, tetradecyl, hexadecyl, or octadecyl substituents. The organoreactive alkoxysilane may include amino, methacryloxy, vinyl, glycidoxy, epoxycyclohexyl, isocyanurate, isocyanate, mercapto, thio, vinyl-benzyl-amino, benzyl-amino, or phenyl-amino substituents. Alternatively, the filler treatment agent may include an organopolysiloxane. Alternatively, certain filler treatment agents (such as chlorosilanes) may hydrolyze on the filler surface. Alternatively, the filler treatment agent may utilize multiple hydrogen bonds (clustered or dispersed or both) as a method of bonding the organosiloxane to the filler surface. The organosiloxane capable of hydrogen bonding has, on average, at least one silicon-bonded group capable of hydrogen bonding per molecule. This group may be selected from: a monovalent organic group having multiple hydroxyl functional groups or a monovalent organic group having at least one amino functional group. Hydrogen bonding may be the primary mode of bonding between the organosiloxane and the filler. The organosiloxane may not be able to form a covalent bond with the filler. The organosiloxane capable of hydrogen bonding may be selected from the group consisting of: a saccharide-silicone polymer, an amino-functionalized organosiloxane, and a combination thereof. Alternatively, the polyorganosiloxane capable of hydrogen bonding may be a saccharide-silicone polymer.

[0067] Alternatively, the filler treating agent may include alkyl mercaptans (such as octadecyl mercaptan, etc.) and fatty acids (such as oleic acid, stearic acid), titanates, titanate coupling agents, zirconate coupling agents, and combinations thereof. One skilled in the art can optimize the filler treating agent to aid filler dispersion without undue experimentation.

[0068] The starting material (e) can be one additional filler or a combination of two or more additional fillers that differ from one another in at least one characteristic, such as filler type, method of preparation, treatment or surface chemistry, filler composition, filler shape, filler surface area, average particle size, and / or particle size distribution. When present, the additional filler can be added to the composition in an amount of >0% to 30%, alternatively 5% to 15%, and alternatively 10% to 15%, based on the combined weight of all starting materials in the composition.

[0069] When selecting starting materials for inclusion in the composition, there may be overlap between starting material types, as some starting materials described herein may have more than one function. For example, (e) an additional filler may function as an additional filler, as a colorant, and even as a flame retardant, such as carbon black. When selecting starting materials for the composition, the components selected may differ from one another.

[0070] Preparation method

[0071] The present invention also relates to a method for preparing a wood-plastic composite (WPC) product. The method comprises:

[0072] (1) The following starting materials are combined

[0073] 15 to 70 wt% of (a) a lignocellulose-based filler;

[0074] 29.5 to 84.5 weight percent of (b) a vinyl polymer;

[0075] 0.5 wt% to 6 wt% of a compound having the formula (c) a polydiorganosiloxane wherein each R is an independently selected monovalent hydrocarbon group having 1 to 18 carbon atoms free of aliphatic unsaturation, and the subscript x is sufficient for the polydiorganosiloxane to have a viscosity of from >350 mPa·s to 100,000 mPa·s as measured at 25°C on a Brookfield DV-III cone and plate viscometer with a #CP-52 spindle at 0.1 to 50 RPM; and

[0076] 0 to 4 wt% of (d) a maleated vinyl polymer;

[0077] each based on the combined weight of starting materials (a), (b), (c), and (d); thereby preparing a composition; and

[0078] (2) Preparing WPC products from the composition.

[0079] In step (1), a composition is formed by combining at least (a) a lignocellulose-based filler, (b) a vinyl polymer, and (c) a polydiorganosiloxane, along with any optional starting materials present in the composition. When (c) the polydiorganosiloxane is in the form of a solid carrier component, the method may include combining (a) the lignocellulose-based filler, (b) the vinyl polymer, and the solid carrier component comprising (c) the polydiorganosiloxane.

[0080] The starting materials of the composition can be combined in any order and via any suitable manner. For example, (b) vinyl polymer can be melted before, during and / or after forming the composition. For example, (b) vinyl polymer can be heated before and / or during the combination of the starting materials so that (a) lignocellulose-based filler and (c) polydiorganosiloxane are combined with (b) vinyl polymer in molten form. Starting materials (a) lignocellulose-based filler and (c) polydiorganosiloxane can be combined with (b) vinyl polymer in molten form in any order (for example, individually, sequentially, together or simultaneously). However, alternatively, when preparing the composition, (b) vinyl polymer can be combined with (a) lignocellulose-based filler and (c) polydiorganosiloxane before heating or melting (b) vinyl polymer so that (b) vinyl polymer is solid and not melted or not softened. Alternatively, when preparing the composition, (a) lignocellulose-based filler and (c) polydiorganosiloxane can be combined and heated, then added to (b) vinyl polymer in solid or liquid form.

[0081] Before, during, and / or after forming the composition, the starting material (b) vinyl polymer is heated to a temperature greater than the melting temperature of the (b) vinyl polymer, for example, 10°C to 90°C, alternatively 10°C to 40°C, higher than the melting temperature of the (b) vinyl polymer. This ensures melting of the (b) vinyl polymer rather than merely softening. Alternatively, lower temperatures may be used in combination with shearing or mixing to ensure softening and / or melting of the (b) vinyl polymer.

[0082] The starting material (c), polydiorganosiloxane, can be in liquid form or delivered as a solid carrier component. The solid carrier component is solid at room temperature and is a combination of (i) the polydiorganosiloxane described above as starting material (c) and (ii) a polymer component selected from the group consisting of a vinyl polymer (as described above for starting material (b)), a maleated vinyl polymer (as described above for starting material (d)), or a combination of a vinyl polymer and a maleated vinyl polymer. The solid carrier component may also optionally contain a filler, as described below.

[0083] Alternatively, (a) the lignocellulose-based filler and (c) the polydiorganosiloxane and at least one other starting material (e.g., one or more of the additional starting materials (e) to (n) described above) can be combined to form a mixture, and the mixture can be combined with the (b) vinyl polymer (and any other additional starting materials) to form a composition. Combining the (a) lignocellulose-based filler and the (c) polydiorganosiloxane can be referred to as surface treating, wetting, or pre-treating the (a) lignocellulose-based filler, which can be in addition to or in lieu of surface treating the (a) lignocellulose-based filler as described herein. Alternatively, the (a) lignocellulose-based filler and the (c) polydiorganosiloxane can be combined by spraying, dipping, blending, or mixing. Combining the (a) lignocellulose-based filler and the (c) polydiorganosiloxane can also include heating, for example, to combine the (c) polydiorganosiloxane with the (a) lignocellulose-based filler. Optionally, the resulting combination of (a) the lignocellulose-based filler and (c) the polydiorganosiloxane may be compacted prior to pelletizing to form pellets (if pellets are used). Combining (a) the lignocellulose-based filler and (c) the polydiorganosiloxane may be performed in a separate process or may be integrated into an existing (e.g., extrusion) process for preparing WPC articles in a premixing step. In the premixing step, the starting materials may be blended together prior to feeding into the extruder. For example, all or a portion of the (a) lignocellulose-based filler, (c) the polydiorganosiloxane, and (b) the vinyl polymer, along with one or more optional starting materials, may be mixed in the premixing step and then fed into the extruder.

[0084] Alternatively, (c) the polydiorganosiloxane may be present in a solid support component comprising, alternatively consisting essentially of, or alternatively consisting of: (a) a lignocellulose-based filler and (c) the polydiorganosiloxane; and the solid support component may be heated. Alternatively, the solid support component may be heated under vacuum. This may be done for a variety of reasons, such as to evaporate the support vehicle (if any), to evaporate other components present in the mixture used to form the solid support component, or to improve the mechanical properties of the solid support component prior to use in the process.

[0085] The composition can be formed, for example, with a suitable mixing device under mixing or shearing. For example, the composition can be formed in a container equipped with an agitator and / or mixing blades. The container can be, for example, an internal mixer, such as a Banbury mixer, a Sigma (Z) blade internal mixer or a cavity transfer mixer. Alternatively or in addition thereto, the composition can be formed in an extruder or processed by an extruder, the extruder can be any extruder, for example, a single screw extruder with a rotating and / or reciprocating (co-kneader) screw, and a multi-screw device comprising two or more screws, the screws can be aligned tangentially or partially / completely in meshing engagement, thereby rotating in a co-rotating or counter-rotating direction. Alternatively, a conical extruder can be used to form WPC compositions as described herein.

[0086] In the method for preparing a WPC article as described above, the method further includes forming the WPC article from the composition in step 2). The composition can, for example, be prepared in a container and subsequently removed from the container to form the article using a separate device. Alternatively, the same device can be used to prepare the composition and subsequently form the WPC article. For example, the composition can be prepared and / or mixed in an extruder, and the extruder can be used to form the WPC article from the composition. Alternatively, the WPC article can be formed via molding (e.g., using an injection molding, compression molding, or transfer molding process). The composition can be formed independently and, once formed, placed in a mold.

[0087] The above method includes forming a WPC article from a composition, which may include forming the composition into a desired shape. The desired shape depends on the end-use application of the WPC article. Those skilled in the art understand how to select and create a die for extrusion and a mold for molding based on the desired shape of the WPC article.

[0088] The method can be performed continuously or semi-continuously in an extruder, such as a twin-screw extruder, in which the screws rotate simultaneously, partially or fully intermeshing, or alternatively, tangentially or partially or fully intermeshingly in counter-rotating alignment. The starting material (c) polydiorganosiloxane (in liquid form or as part of a solid carrier component) can be placed in the extruder simultaneously with (a) the lignocellulose-based filler and (b) the vinyl polymer. Alternatively, the polydiorganosiloxane can be placed in the extruder after melting the (b) vinyl polymer and before adding the (a) lignocellulose-based filler. Alternatively, the polydiorganosiloxane can be placed in the extruder after the (a) lignocellulose-based filler and (b) vinyl polymer and before the WPC article exits the extruder. Alternatively, (a) the lignocellulose-based filler and the polydiorganosiloxane can be placed simultaneously in an extruder, where they are heated to achieve surface treatment of (a) the lignocellulose-based filler and (c) the polydiorganosiloxane. (b) The vinyl polymer can then be placed in the extruder to obtain a mixture, and the temperature is raised to a temperature suitable for compounding the mixture and forming the WPC article. The extruder can have one or more zones, such as 1 to 3, or 3 to 8, or 1 to 12 zones, in which the starting materials can be added. These zones can be heated at different temperatures.

[0089] Alternatively, the (b) vinyl polymer can be placed in the first zone of the extruder, which is heated within + / - 30°C of the melting temperature of the (b) vinyl polymer. The starting material (c) polydiorganosiloxane, which can be delivered as a solid carrier component, can be placed in the second or later zone of the extruder, which can be heated at 10 to 90°C above the melting temperature of the (b) vinyl polymer. As mentioned above, the temperature used is generally less than the degradation temperature of the starting material of the composition. Alternatively, the die of the extruder can also be heated, and the temperature used by the extruder, including the temperature of any zone and the die, can be selected so that the temperature does not exceed the degradation temperature of the (a) lignocellulose-based filler. As will be appreciated by those skilled in the art, the degradation temperature of the (a) lignocellulose-based filler depends on its selection.

[0090] The above method can be used to produce various WPC products, such as building materials. Such WPC building materials include residential and / or commercial buildings and construction products and applications, such as decking, railings, siding, fencing, window frames, trim, skirting, and flooring. When the building material is a decking, the method may optionally further include step 3) of adding a cap stock layer after step 2).

[0091] Solid carrier component composition

[0092] As described above, (c) polydiorganosiloxane may be added to the composition for preparing the WPC article in the form of a solid carrier component. The solid carrier component may comprise, alternatively may consist essentially of, and alternatively may consist of:

[0093] 5 to 35 wt% of (i) the polydiorganosiloxane described above as starting material (c);

[0094] 65 to 95 wt% of (ii) a polymer component selected from the group consisting of:

[0095] a vinyl polymer as described above for the starting material (b),

[0096] a maleated vinyl polymer as described above for starting material (d), and

[0097] A combination of both a vinyl polymer and a maleated vinyl polymer; and

[0098] 0% to 10% of (iii) filler.

[0099] The starting material (i) polydiorganosiloxane in the solid carrier component is as described above for starting material (c). The starting material (ii) polymer component may comprise a vinyl polymer and may be free of maleated vinyl polymer. The vinyl polymer in the solid carrier component is as described above for starting material (b). Alternatively, in the solid carrier component, the vinyl polymer may be selected from the group consisting of LLDPE, HDPE, and combinations thereof, alternatively, the vinyl polymer in the solid carrier component may be HDPE. The HDPE used in the solid carrier component may have a melt index of >2 g / 10 min, alternatively from 2.3 g / 10 min to 20 g / 10 min, alternatively from 2.3 g / 10 min to 12 g / 10 min, alternatively from 2.3 g / 10 min to 6 g / 10 min, alternatively from 4.4 g / 10 min to 20 g / 10 min, and alternatively from 4.4 g / 10 min to 12 g / 10 min. Alternatively, (ii) the polymer component may be a maleated vinyl polymer, and the solid carrier component may not contain a vinyl polymer. The maleated vinyl polymer used in the solid carrier component may be as described above for starting material (d). Alternatively, (ii) the polymer component may include both the vinyl polymer and the maleated vinyl polymer. The filler in the solid carrier component is optional. When present, the filler may include a lignocellulose-based filler as described above for starting material (a), an additional filler such as a mineral filler as starting material (e), or a combination of the lignocellulose-based filler and the additional filler. Alternatively, the filler in the solid carrier component may be a mineral filler, and alternatively the mineral filler may be selected from the group consisting of talc, calcium carbonate, and combinations thereof. Alternatively, the filler in the solid carrier component may be talc. Alternatively, the solid carrier component may comprise 10% to 30% of (i) polydiorganosiloxane, 70% to 90% of (ii) the polymer component, and 0% to 10% of (iii) the filler. Alternatively, the solid carrier component may comprise 10% to <25% of (i) polydiorganosiloxane, alternatively 10% to 20% polydiorganosiloxane. Alternatively, the solid carrier component may comprise 0% filler. Alternatively, the solid carrier component may comprise >75% to 90% of (ii) polymer component, alternatively 80% to 90% of (ii) polymer component.

[0100] The solid carrier component is solid at ambient temperature and pressure (e.g., 25° C. and 1 atmosphere). The solid carrier component can be formed by combining the starting materials in any order. The solid carrier component can be prepared by dispersing, for example, with a suitable mixing device, under mixing or shearing, a mixed composition formed by (ii) the polymer component and (i) the polydiorganosiloxane and (when present) (iii) the filler. For example, the mixed composition can be dispersed in a container equipped with an agitator and / or mixing blades. The container can be, for example, an internal mixer, such as a Banbury mixer, a Sigma (Z) blade internal mixer, or a cavity transfer mixer. Alternatively or in addition, the mixed composition can be dispersed in an extruder or processed by an extruder, the extruder can be any extruder, for example, a single screw extruder with a rotating and / or reciprocating (co-kneader) screw and a multi-screw device comprising two or more screws, the screws being tangentially aligned or partially / completely meshing with each other, thereby rotating in a co-rotating or counter-rotating direction. Alternatively, a conical extruder may be used to disperse the mixed compositions described herein.

[0101] The solid carrier component prepared as described above is reprocessable, and can be prepared for feeding in subsequent processes. The composition of the mixing prepared as described above can be, for example, substantially continuous band or discontinuous pellet or particle or powder. Substantially continuous band can be formed by pressurizing the composition mixed and passing it through a die head to produce continuous strand or band, and these strands or bands are cooled subsequently before suitable packaging. Alternatively, strand or band can be pulverized to form pellet or powder. When mixing apparatus is an extruder, the mixing apparatus can also produce the required pressure and / or heat of the composition mixed by die head processing, and the extruder can be any extruder, for example BUSS kneader or the single screw extruder with rotation and / or reciprocating (kneader altogether) screw and the multi-screw device comprising two or more screws, the screw can tangentially or partially / fully intermeshingly align, thereby rotating in corotation or counterrotation direction. Conical extruder can be used for mixing and pressurized mixed composition. Alternatively, a gear pump can be used to generate the pressure required for extrusion after the starting materials have been mixed to form the mixed composition. A discontinuous form of the mixed composition can be produced by cutting the continuous strip of the mixed composition into shorter lengths. Alternatively, bulky mixed compositions can be reduced to a usable size using a grinder or pulverizer.

[0102] The solid carrier component can be formed by a method performed continuously or semi-continuously in an extruder such as a twin-screw extruder (wherein the screws rotate simultaneously, partially or completely intermeshing, alternatively tangentially or partially or completely intermeshingly counter-rotatingly aligned). Alternatively, (i) the polydiorganosiloxane can be placed in an extruder simultaneously with the polymer component and optionally (iii) the filler. Alternatively, the (i) polydiorganosiloxane can be placed in an extruder after melting the (ii) polymer component (and before adding the (iii) filler, if any, which will be added to the mixed composition). Alternatively, the (i) polydiorganosiloxane can be placed in an extruder after the (iii) filler (when present) and before the (ii) polymer component, and before the mixed composition leaves the extruder. Alternatively, the (iii) filler can be placed in an extruder simultaneously with the (i) polydiorganosiloxane, and then the polymer component can be placed in an extruder to obtain a mixture, and the temperature is raised to a temperature suitable for compounding the mixture. The extruder may have one or more zones, such as 1 to 3, alternatively 1 to 12, alternatively 3 to 12, or alternatively 3 to 10 zones, in which the starting materials may be added. These zones may be heated at different temperatures and incorporate various functional stages, including conveying, melting, mixing, degassing, vacuum, pressurization, and forming.

[0103] Alternatively, the polymer component (ii) can be placed in the first zone of the extruder, which is heated within + / - 30°C of the melt temperature of the polymer component. The polydiorganosiloxane (i) can be placed in the second zone of the extruder, which is heated at 10°C to 90°C above the melt temperature of the polymer component (ii). The starting material (iii) filler (when present) is placed in one or more of the first zone, the second zone, or a subsequent zone of the extruder. As described above, the temperature used is generally less than the degradation temperature of the solid support component starting material. Before pressurization and forming in the die of the extruder, the mixture can be stripped to remove any air, moisture, or by-products. The vacuum zone, pressurization zone, and forming zone can also be heated, and the temperature used in the extruder (including the temperature of any zone and the die) does not exceed the degradation temperature of the starting materials (i), (ii), and (iii) (when present). As will be understood by those skilled in the art, the degradation temperature of the starting materials (i), (ii), and (iii) depends on their selection. The resulting extruded strands can be comminuted in any convenient manner to form the solid support component.

[0104] The solid carrier component is typically in the form of particles and can be, for example, in the form of particles, pellets, or powders. The average particle size of the solid carrier component is a function of the desired properties and its end use. The solid carrier component can be a powder. Alternatively, the solid carrier component can be a pellet. Pellets typically have a larger average particle size than powders.

[0105] Example

[0106] These examples are intended to illustrate the present invention to those skilled in the art and are not to be construed as limiting the scope of the invention described in the claims.The starting materials in Table 3 were used in these examples.

[0107] Table 3 - Starting Materials

[0108]

[0109]

[0110] The vinyl polymers (PE) and maleated vinyl polymers (MAPE) in Table 3 are each commercially available from The Dow Chemical Company, Midland, Michigan, USA. In Table 3, density is measured by ASTM D792-13; I2 values ​​are measured by ASTM D1238-13 at 190°C and a 2.16 kg load; and melt temperature is measured by DSC, wherein the film is conditioned at 230°C for 3 minutes and then cooled to a temperature of -40°C at a rate of 10°C / minute. After holding the film at -40°C for 3 minutes, the film is heated to 200°C at a rate of 10°C / minute. The polydiorganosiloxanes are each commercially available from The Dow Silicones Company, Midland, Michigan, USA, and their viscosities are measured at 25°C on a Brookfield DV-III cone and plate viscometer with a #CP-52 spindle at 0.1 to 50 RPM.

[0111] Reference Example 1 – Procedure for preparing WPC samples

[0112] The compositions of these examples were produced using a twin-screw extruder. The compositions were processed in a twin-screw extruder and pelletized by cutting the extruded strands. The pelletized material was then used in subsequent processes.

[0113] The starting material (a) lignocellulose-based filler is added separately from the (b) vinyl polymer and (c) polydiorganosiloxane via a second feed system located at a downstream position in the extruder barrel. By mixing the solids into the fully molten blend of vinyl polymer and polydiorganosiloxane, samples with higher filler content can be produced than would be possible by feeding all materials at the same point.

[0114] Specimens were prepared using injection molding. Tensile bars were prepared and tested according to ASTM D638-14. Each composition was processed using the same conditions as those used for compounding in a twin-screw extruder and injection molding equipment for consistency. For each example, the total feed rate, RPM, temperature, and equipment configuration of each composition were kept constant for both the compounding extruder and the injection molding equipment.

[0115] The parameters associated with extrusion, as well as the average breaking strength, strand mass, and color of the final injection molded tensile bars of the wood-plastic composite articles formed from each example are shown in the table below.

[0116] Melting temperatures were obtained using a thermocouple hand probe. Because this measurement requires a certain level of skill due to the manual method, it is subject to a high degree of variability. Experience has shown that results can vary by up to 10°C, depending on the operator and technique. In the case of these tests, it was necessary to use the same operator and technique for both the (a) lignocellulose-based filler and (b) vinyl polymer systems to minimize this error.

[0117] Extruder torque is reported as a relative percentage of the extruder maximum torque.

[0118] The breaking strength was measured by producing an average of five samples. The test was performed according to ASTM D638-14.

[0119] Color (Y) was also measured to quantify the level of thermal decomposition occurring in the wood filler. The Y value, or brightness, was measured as a measure of the darkening of the wood-plastic composite during processing. Higher Y values ​​correspond to lighter brown colors in the wood. The Y value was measured using a BYK Spectral Guide 45 / 0 glossmeter with a D65 illuminant and a 10° observer, taking the average of two measurements (average of 10 measurements) on five individual injection-molded tensile dogbone samples.

[0120] Strand quality was determined by visually assessing melt fracture, ability to maintain pelletizing strength, and roughness.

[0121] The comparative example compositions are shown in Table 4. The amount of each starting material is in wt %.

[0122] Table 4.

[0123]

[0124] In Table 4, the balance of each composition is (b) vinyl polymer. Comparative Examples 1 and 2 show controls in which no polydiorganosiloxane was added. Comparative Examples 3 and 4 show controls in which the polydiorganosiloxane selected had a viscosity that was too low for the application under the conditions tested.

[0125] Table 5 shows the properties of the samples prepared as shown in Table 4.

[0126] Table 5

[0127]

[0128] NA* means not applicable.

[0129] The compositions of the working examples are shown in Table 6. The amount of each starting material is in wt %.

[0130] Table 6

[0131]

[0132]

[0133] The starting material (b) polymer was the balance of each sample shown in Table 6. Table 7 shows the properties of the samples prepared as shown in Table 6.

[0134] Table 7

[0135]

[0136]

[0137] ND = Not Determined

[0138] In this reference example A, a 26mm twin-screw extruder is used to prepare the solid carrier component in pellet form. Starting material (ii) vinyl polymer and (when used) (ii) maleated vinyl polymer are fed via the feed throat in the first barrel section. When used, (ii) filler CaCO (calcium carbonate, which is untreated and has an average particle size of 3 μm) is also fed via the feed throat in the first barrel section. Under mixing, starting material (i) polydiorganosiloxane is injected onto the screw section in the fourth of the eleven barrel sections. The resulting composition is granulated using a Gala underwater pelletizer to obtain consistency, and collected for testing. Before any test, all samples were cooled to room temperature and aged for a minimum of 48 hours.

[0139] In Reference Example B, a 25 mm twin-screw extruder was used to prepare the solid carrier component in pellet form. Starting materials (b) vinyl polymer and (when used) (d) maleated vinyl polymer were fed through the feed throat in the first barrel section. Under mixing, starting material (c) polydiorganosiloxane was injected into the screw section in the fourth of the twelve barrel sections. The resulting composition was cooled by complete immersion in a water bath and pelletized using a strand pelletizer.

[0140] In this Reference Example C, the exudation of polydiorganosiloxane from the pellets prepared in Reference Examples A and B as described above was evaluated as follows. Each sample (4 g) was placed in a pre-weighed container lined with The pellets were placed in an aluminum pan with #1 filter paper (5.5 cm in diameter) so that the surface of the pan was completely covered with the filter paper, but the filter paper was not bent. The pellets were evenly spread on the filter paper in a semi-uniform layer. The sample was allowed to stand on a workbench at room temperature or in a convection oven at the temperature for the aging time. After aging, the pellets were allowed to stand at room temperature for at least 4 hours and placed in a 20 mL scintillation vial. The filter paper was weighed to determine the weight of the aged filter paper. The exudate was determined according to the following formula:

[0141]

[0142] The composition, aging conditions, and polydiorganosiloxane exudation of pellets prepared according to Reference Example A (25 to 27 and 35) and Reference Example B (28 to 34) and tested according to Reference Example B are reported in Table 9 below.

[0143] Table 9

[0144]

[0145]

[0146] Issues to be resolved

[0147] WPC products are typically made by high-shear methods such as extrusion or injection molding. Lignocellulose-based fillers are used to change mechanical properties, reduce costs (because these are generally cheaper than vinyl polymers), reduce density, and / or meet the end-use requirements of various applications. Adding fillers can make the starting material difficult to process because fillers generally increase the viscosity of the molten vinyl polymer. When processing the starting material with a high-shear method, these fillers may require more processing work, resulting in higher temperatures and limited extrusion rates. This increase in temperature and stress can lead to thermal or mechanical decomposition of the lignocellulose-based filler. Similarly, some vinyl polymers can suffer from decomposition under the mechanical or thermal stress from processing. This decomposition translates into poor mechanical properties, discoloration, poor aesthetics, and / or other defects in the prepared WPC products. Similarly, such processing difficulties translate into the need for higher energy input, increased torque, and reduced processing speed for processing. The combination of these effects can lead to lower output and / or poorer product quality for the compounder.

[0148] Industrial Applications

[0149] The above examples demonstrate that by adding a polydiorganosiloxane during processing, torque can be significantly reduced. Reducing torque also reduces energy requirements and lowers the melt temperature of the composition. This temperature reduction can enable higher throughput, improved material properties, higher filler loading, improved properties of the WPC article, and / or reduce the costs associated with producing the WPC article. This reduction in torque, pressure, work, and temperature can also minimize or eliminate process-related decomposition of the vinyl polymer and / or filler. Surprisingly, it has been discovered that this reduction in melt temperature (approximately 5°C to 30°C, alternatively 10°C to 20°C) can be achieved by using a polydiorganosiloxane (e.g., trimethylsiloxy-terminated polydimethylsiloxane) that lacks silicon-bonded groups other than monovalent hydrocarbon groups free of aliphatic unsaturation.

[0150] It was also discovered that polydiorganosiloxanes with viscosities greater than 350 mPa·s but less than or equal to 100,000 mPa·s provide one or more of the aforementioned benefits. Working Examples 1-22 demonstrate that using 0.5% to 6% of polydiorganosiloxane in the composition significantly reduces the torque with the polydiorganosiloxane to values ​​between 39% and 72%, compared to the 81% to 82% observed without the polydiorganosiloxane in Comparative Examples 1 and 2. Furthermore, Working Examples 1 to 11, 13 to 19, and 21 to 22 exhibit lower melting temperatures than those in Comparative Examples 1 and 2. Alternatively, the viscosity of the polydiorganosiloxane may be between 5,000 and 20,000 mPa·s. It has been found that for high viscosity siloxanes (i.e., >100,000 mPa·s, alternatively 60,000 mPa·s), under the conditions tested in the above Examples and Comparative Examples, the change in melt temperature during extrusion is less significant, making some high viscosity polydimethylsiloxanes less useful than low viscosity polydimethylsiloxanes. Working Examples 12 and 20 have lower levels (1%) of higher viscosity, i.e., 60,000 mPa·s and 100,000 mPa·s, respectively. For lower viscosity polydimethylsiloxanes (e.g., ≤350 mPa·s) under the conditions of the above Comparative Examples, the low viscosity polydimethylsiloxane may not be sufficiently distributed throughout the vinyl polymer, resulting in the surge observed at the extrusion die in Comparative Examples 3 and 4.

[0151] Additionally, it has been found that the use of a polydiorganosiloxane having a viscosity greater than 350 mPa·s but less than or equal to 100,000 mPa·s in combination with a wood filler, which is a combination of hardwoods such as maple, poplar, ash, and beech, with typical α-cellulose levels of 42%-47%, 45%, 40%-41%, and 49% and lignin levels of 21%-22%, 16%, 26%, and 22%, respectively, according to results reported by RC Pettersen in a book chapter entitled "The Chemical Composition of Wood," enables the production of composite materials with reduced darkening compared to samples without additives. The level of lignin in the wood flour is much higher than that defined in U.S. Patent 6,743,507, which outlines that cellulose pulp fibers need to contain greater than 80% α-cellulose and less than 2% lignin to achieve reduced discoloration. Color was measured using the lightness (Y) value of an XYZ scale representing a light to dark scale (100 is white and 0 is black / no reflected light). The results show that in the absence of polydiorganosiloxane, the Y values ​​in Comparative Examples 1 and 2 were low (4.5 to 6.7). However, when polydiorganosiloxane was added, Y ranged from 6.9 to 27.4, with the lowest Y values ​​reflecting the lower levels of polydiorganosiloxane.

[0152] Examples 23 to 25 show that solid support components comprising polydiorganosiloxanes as described herein can be prepared. Examples 23 and 24 show that solid support components having low exudation of polydiorganosiloxane can be prepared. "Low exudation" means that less than 1.5% of the siloxane migrates out of the solid support component after aging at 70°C for at least 2 weeks, as measured by the test method in Reference Example B. Working Examples 23 and 24 show that low exudation solid support components can be prepared using 60% to 80% by weight HDPE, 0 to 20% by weight maleated vinyl polymer, and up to 20% by weight bistrimethylsiloxy-terminated polydimethylsiloxane to produce low exudation pellets.

[0153] Definition and Usage of Terms

[0154] Unless the context of this specification indicates otherwise, all quantities, ratios and percentages herein are by weight; the articles "a", "an" and "the" each refer to one (a kind) or more (a variety); and the singular includes the plural. The Summary of the Invention and the Abstract are hereby incorporated by reference. The transitional phrases "comprising", "consisting essentially of" and "consisting of" are used as described in the Manual of Patent Examining Procedure, Ninth Edition, revised in August 2017, last revised in January 2018, Sections 2111.03I., II. and III. The use of "for example", "for example", "such as" and "including" to list exemplary examples is not meant to be limited to the listed examples. Therefore, "for example" or "such as" means "for example, but not limited to" or "such as, but not limited to" and covers other similar or equivalent examples. The abbreviations used herein have the definitions in Table 10.

[0155] Table 10 - Abbreviations

[0156]

[0157]

[0158] The following test methods were used to measure the properties of the starting materials herein.

[0159] The melt index (abbreviated as I2 or I2) of vinyl polymers and maleic acid vinyl polymers is measured according to ASTM D1238-13 at 190°C and a load of 2.16 kg. The melt index value is reported in g / 10 min.

[0160] Samples of vinyl polymers and maleated vinyl polymers were prepared for density measurement according to ASTM D4703. Density measurements were made according to ASTM D792, Method B, within one hour of sample pressing.

[0161] The peak melting points (melting temperatures) of the vinyl polymer and the maleated vinyl polymer were determined by DSC, wherein the film was conditioned at 230° C. for 3 minutes and then cooled at a rate of 10° C. / minute to a temperature of −40° C. After holding the film at −40° C. for 3 minutes, the film was heated to 200° C. at a rate of 10° C. / minute.

[0162] "MWD" is defined as the ratio of weight average molecular weight to number average molecular weight (MWD). w / M n ). M w and M n Measured according to conventional GPC method.

[0163] The viscosity of each polydiorganosiloxane was measured on a Brookfield DV-III cone and plate viscometer with a #CP-52 spindle at 0.1 RPM to 50 RPM. One skilled in the art will recognize that the rotation rate decreases as viscosity increases and will be able to select an appropriate rotation rate when measuring viscosity using this test method.

[0164] The present invention has been described in an exemplary manner, and it should be understood that the terminology used is intended to be in the nature of words of description rather than of limitation. To the extent that any Markush group is relied upon herein to describe a particular feature or aspect, different, special, and / or unexpected results may be obtained from each member of the corresponding Markush group independent of all other Markush members. Each member of the Markush group may be relied upon individually and / or in combination and provides adequate support for specific embodiments within the scope of the appended claims.

[0165] In addition, any ranges and sub-ranges relied upon in describing the present invention are independently and collectively within the scope of the appended claims and should be understood to describe and contemplate all ranges including all and / or partial values ​​therein, even if such values ​​are not explicitly stated herein. Those skilled in the art will readily recognize that the enumerated ranges and sub-ranges fully describe and enable various embodiments of the present invention, and that such ranges and sub-ranges can be further delineated as being related to one-half, one-third, one-quarter, one-fifth, etc. As just one example, a range of "1 to 18" can be further delineated as a lower third (i.e., 1 to 6), a middle third (i.e., 7 to 12), and an upper third (i.e., 13 to 18), which are individually and collectively within the scope of the appended claims and can be relied upon individually and / or collectively and provide sufficient support for specific embodiments within the scope of the appended claims. In addition, with respect to language such as "at least," "greater than," "less than," "not more than," etc., which limits or modifies a range, it should be understood that such language includes sub-ranges and / or upper or lower limits.

[0166] Embodiments of the present invention

[0167] In a first embodiment, a composition for preparing a wood-plastic composite article comprises:

[0168] 40 to 70 wt% of (a) a lignocellulose-based filler;

[0169] 29 to 59 weight percent of (b) a vinyl polymer;

[0170] 1% to 4% by weight of a compound having the formula (c) a polydialkylsiloxane wherein each R is an independently selected alkyl group having from 1 to 18 carbon atoms, and the subscript x has a value sufficient to provide the polydialkylsiloxane with a viscosity of from 5,000 to 50,000 mPa·s as measured at 25° C. on a Brookfield DV-III cone and plate viscometer with a #CP-52 spindle at 0.1 to 50 RPM; and

[0171] 0 to 4 wt% of (d) a maleated vinyl polymer;

[0172] Each is based on the combined weight of starting materials (a), (b), (c) and (d) in the composition.

[0173] In a second embodiment, in the composition according to the first embodiment, the starting material (a) the lignocellulose-based filler comprises a lignocellulose material derived from wood, plants, agricultural by-products, rice husks, sisal, bagasse, wheat straw, kapok, ramie, gray leaf sisal, corn fiber or coconut shells, nut shells, flax, jute, hemp, kenaf, rice husks, abaca, peanut shells, bamboo, straw, lignin, starch, or cellulose and cellulose-containing products, and combinations thereof, and the starting material (a) is present in an amount of 45% to 65% by weight.

[0174] In a third embodiment, in the composition according to the first or second embodiment, the lignocellulose-based filler is a wood filler, (a) the wood filler comprising lignin in an amount of 18 to 35 wt.-% and carbohydrates in an amount of 65 to 75 wt.-%, and optionally inorganic minerals in an amount of up to 10 wt.-%.

[0175] In a fourth embodiment, in the composition according to any one of the preceding embodiments, (a) the lignocellulose-based filler is a wood filler comprising 29 to 57 wt% α-cellulose.

[0176] In a fifth embodiment, in the composition according to any one of the preceding embodiments, the starting material (b) said ethylene-based polymer is selected from the group consisting of high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), low density low molecular weight polyethylene (LDLMWPE), and combinations thereof, and the starting material (b) is present in an amount of 31 wt% to 51 wt%.

[0177] In a sixth embodiment, in the composition according to any one of the preceding embodiments, (b) the ethylene-based polymer is selected from the group consisting of HDPE, LLDPE, and combinations thereof.

[0178] In a seventh embodiment, in the composition according to any one of the preceding embodiments, (b) the ethylene-based polymer comprises ≥ 50% recycled polyethylene.

[0179] In an eighth embodiment, in the composition according to any of the preceding embodiments, in the starting material (c) the polydiorganosiloxane, each R is an alkyl group having 1 to 12 carbon atoms, the subscript x has a value sufficient to provide the polydiorganosiloxane with a viscosity of 5,000 to 20,000 mPa·s, and the starting material (c) is present in an amount of 1 to 2 weight percent.

[0180] In a ninth embodiment, in the composition according to any one of the preceding embodiments, in the starting material (c) the polydiorganosiloxane, each R is an alkyl group having 1 to 6 carbon atoms, and the subscript x has a value sufficient to provide the polydiorganosiloxane with a viscosity of 5,000 to 15,000 mPa·s.

[0181] In a tenth embodiment, in the composition according to any one of the preceding embodiments, the starting material (c) is a trimethylsiloxy-terminated polydimethylsiloxane.

[0182] In an eleventh embodiment, in the composition according to any of the preceding embodiments, starting material (d) the maleated vinyl polymer is present and has a melt index of 2 to 25 g / 10 min as measured at 190° C. and 2.16 Kg according to ASTM D1238-13 and a maleic anhydride content of 0.25 to 2.5 wt %.

[0183] In a twelfth embodiment, in the composition according to any of the preceding embodiments, the composition further comprises an additional starting material selected from the group consisting of: (e) an additional filler other than the lignocellulose-based filler of starting material (a), (f) a colorant, (g) a blowing agent, (h) a UV stabilizer, (i) an antioxidant, (j) a processing aid, (k) a preservative, (l) a biocide, (m) a flame retardant, (n) an impact modifier, and (o) a combination of two or more of (e) to (n).

[0184] In a thirteenth embodiment, in the composition according to any one of the preceding embodiments, the starting material (e) the additional filler is present in an amount of 10% to 15% by weight, and the starting material (e) is a mineral filler.

[0185] In a fourteenth embodiment, a method for preparing a wood-plastic composite article comprises:

[0186] (1) preparing the composition according to any one of the preceding claims by combining the starting materials; and

[0187] (2) forming the wood-plastic composite product from the composition.

[0188] In a fifteenth embodiment, the method according to the fourteenth embodiment further comprises: (i) mixing (a) the lignocellulose-based filler and (b) the vinyl polymer before adding (c) the polydiorganosiloxane; (ii) heating (b) the vinyl polymer to melt (b) the vinyl polymer before and / or during forming the composition; (iii) mixing the mixture of (a) the lignocellulose-based filler and (c) the polydiorganosiloxane before adding (b) the vinyl polymer, or (iv) any combination of (ii) and (i) or (iii).

[0189] In a sixteenth embodiment, the method according to the fourteenth embodiment further comprises: (i) when (c) the polydiorganosiloxane is combined with another starting material of the composition, (c) the polydiorganosiloxane is a liquid; or (ii) (c) the polydiorganosiloxane is present in a solid carrier component, and the method further comprises melting the solid carrier component when (c) the polydiorganosiloxane is combined with another starting material of the composition.

[0190] In a seventeenth embodiment, the method according to any one of the fourteenth to sixteenth embodiments further comprises: (i) forming the wood-plastic composite article from the composition further comprises forming the composition into a desired shape; (ii) forming the wood-plastic composite article from the composition comprises extruding the composition; (iii) forming the wood-plastic composite article from the composition comprises molding the composition; or (iv) any combination of (i) to (iii).

[0191] In an eighteenth embodiment, the method according to any one of the fourteenth to seventeenth embodiments further comprises that the wood-plastic composite product can be used as a building material selected from the group consisting of decking, railings, fences, siding, trim, skirting, and window frames.

[0192] In a nineteenth embodiment, the building material according to the method of the eighteenth embodiment is a decking board, and the method further comprises: 3) adding a cover layer to the decking board after step 2).

[0193] In a twentieth embodiment, the solid support component comprises:

[0194] 10% to 30% by weight of a compound having the formula (i) a polydialkylsiloxane wherein each R is an independently selected alkyl group having from 1 to 18 carbon atoms, and the subscript x has a value sufficient for the polydialkylsiloxane to have a viscosity of from 5,000 mPa·s to 50,000 mPa·s as measured at 25° C. on a Brookfield DV-III cone and plate viscometer with a #CP-52 spindle at 0.1 to 50 RPM; and

[0195] 70 to 90 wt% of (ii) a polymer component selected from the group consisting of:

[0196] vinyl polymers,

[0197] Maleated vinyl polymers, and

[0198] a combination of (b) and (d); and

[0199] 0% to 10% of (iii) filler.

[0200] In a twenty-first embodiment, in the polydiorganosiloxane in the solid support component according to the twentieth embodiment, each R is an alkyl group having 1 to 12 carbon atoms, the subscript x has a value sufficient to provide the polydiorganosiloxane with a viscosity of 5,000 to 20,000 mPa·s, and the polydiorganosiloxane is present in an amount of 15 to 25 weight percent based on the combined weight of all starting materials in the solid support component.

[0201] In a twenty-second embodiment, the polydiorganosiloxane in the solid support component according to the twentieth or twenty-first embodiment has: each R is an alkyl group having 1 to 6 carbon atoms, and the subscript x has a value sufficient to provide the polydiorganosiloxane with a viscosity of 5,000 to 15,000 mPa·s, and the polydiorganosiloxane is present in an amount of 18 to 22 weight percent based on the combined weight of all starting materials in the solid support component.

[0202] In a twenty-third embodiment, the polydiorganosiloxane in the solid support component according to any one of the twentieth to twenty-second embodiments is a trimethylsiloxy-terminated polydimethylsiloxane.

[0203] In a twenty-fourth embodiment, the polymer component of the solid support component according to any one of the twentieth to twenty-third embodiments comprises a vinyl polymer.

[0204] In a twenty-fifth embodiment, the polymer component of the solid support component according to any one of the twentieth to twenty-fourth embodiments comprises high density polyethylene.

[0205] In a twenty-sixth embodiment, the polymer component of the solid support component according to any one of the twentieth to twenty-fifth embodiments comprises a high density polyethylene having a melt index of 2.3 to 20 g / 10 min.

[0206] In a twenty-seventh embodiment, the polymer component according to any one of the twentieth to twenty-sixth embodiments further comprises a maleated vinyl polymer.

[0207] In a twenty-eighth embodiment, the polymer component according to any one of the twentieth to twenty-sixth embodiments does not comprise a maleated vinyl polymer.

[0208] In a twenty-ninth embodiment, the polymer component according to any one of the twentieth to twenty-third embodiments comprises a maleated vinyl polymer and does not comprise a vinyl polymer.

[0209] In a thirtieth embodiment, the filler is present in a solid carrier component according to any one of the twentieth to twenty-ninth embodiments, and the filler comprises talc.

Claims

1. A composition for preparing a wood-plastic composite product, the composition comprising: 45 to 65 wt% of (a) a lignocellulose-based filler; 35 to 55 weight percent of (b) a vinyl polymer; 0.5 wt% to 6 wt% of a compound having the formula (c) a polydiorganosiloxane wherein each R is an independently selected monovalent hydrocarbon group having 1 to 18 carbon atoms free of aliphatic unsaturation, and the subscript x is sufficient for the polydiorganosiloxane to have a viscosity of from >350 mPa·s to 100,000 mPa·s as measured at 25°C on a Brookfield DV-III cone and plate viscometer with a #CP-52 spindle at 0.1 to 50 RPM; and 1 to 3 wt% of (d) a maleated vinyl polymer; Each is based on the combined weight of starting materials (a), (b), (c) and (d) in the composition.

2. The composition according to claim 1, wherein the composition contains 0.5 to 3 wt% of the (c) polydiorganosiloxane. 3 . The composition according to claim 1 , wherein the (c) polydiorganosiloxane has a viscosity of 1,000 to 50,000 mPa·s. The composition according to claim 1 , wherein the (c) polydiorganosiloxane has a viscosity of 1,000 to 20,000 mPa·s. The composition according to claim 1 , wherein the (c) polydiorganosiloxane has a viscosity of 5,000 to 12,500 mPa·s.

6. The composition according to claim 1, wherein the (c) polydiorganosiloxane is a trialkylsiloxane-terminated polydialkylsiloxane.

7. The composition of claim 1, wherein in the (c) polydiorganosiloxane, each R is a methyl group.

8. The composition of claim 1, wherein the composition further comprises >0 to 30 wt% of (e) a filler different from (a) the lignocellulose-based filler.

9. The composition according to claim 8, wherein the (e) filler is a mineral filler.

10. The composition of claim 9, wherein the mineral filler is selected from the group consisting of calcium carbonate, talc, and combinations thereof.

11. A method for preparing a wood-plastic composite product, the method comprising: 1) The following starting materials are combined 45 to 65 wt% of (a) a lignocellulose-based filler; 35 to 55 weight percent of (b) a vinyl polymer; 0.5 wt% to 6 wt% of a compound having the formula (c) a polydiorganosiloxane wherein each R is an independently selected monovalent hydrocarbon group having 1 to 18 carbon atoms free of aliphatic unsaturation, and the subscript x is sufficient for the polydiorganosiloxane to have a viscosity of from >350 mPa·s to <100,000 mPa·s as measured at 25°C on a Brookfield DV-III cone and plate viscometer with a #CP-52 spindle at 0.1 to 50 RPM; as well as 1 to 3 wt% of (d) a maleated vinyl polymer; each based on the combined weight of starting materials (a), (b), (c), and (d) in the composition, thereby preparing a composition; and 2) forming the wood-plastic composite product from the composition. 12 . The composition according to claim 11 , wherein the (c) polydiorganosiloxane has a viscosity of 1,000 to 50,000 mPa·s. 13 . The composition according to claim 11 , wherein the (c) polydiorganosiloxane has a viscosity of 1,000 to 20,000 mPa·s. The composition according to claim 11 , wherein the (c) polydiorganosiloxane has a viscosity of 5,000 to 12,500 mPa·s.

15. The composition according to claim 11, wherein the (c) polydiorganosiloxane is a trialkylsiloxane-terminated polydialkylsiloxane.

16. The composition of claim 11, wherein in the (c) polydiorganosiloxane, each R is a methyl group.

17. The method of claim 11, wherein: (i) preparing the wood-plastic composite article from the composition further comprises forming the composition into a desired shape; (ii) preparing the wood-plastic composite article from the composition comprises extruding the composition; (iii) preparing the wood-plastic composite article from the composition comprises molding the composition; or (iv) any combination of (i) to (iii).

18. The method of claim 11, wherein the wood-plastic composite product is useful as a building material selected from the group consisting of decking, railings, fences, siding, trim, skirting, and window frames.

19. The method of claim 18, wherein the building material is a decking.

20. The method according to claim 19, further comprising step 3) adding a cover layer after step 2).

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