NZ754798B2 - A composite material and composite product - Google Patents

Abstract

The present invention is directed to a composite material comprising a cellulosic material, high impact polystyrene (HIPS) and styrene maleic anhydride (SMA). The cellulosic material may be thermally modified prior to being incorporated into the composite material. The present invention is also directed to a composite product that comprises the composite material according to the invention. cted to a composite product that comprises the composite material according to the invention.

Description

A COMPOSITE MATERIAL AND COMPOSITE PRODUCT Field of the invention The t invention is directed to a composite material comprising a ce!lulosic material, iligh impact polystyrene (HIPS) and styrene maleic anhydride (SMA). Tile cellulosic material may be thermally modified prior to being incorporated into the composite material. The present invention is also directed to a composite product that comprises the composite material ing to the invention.

Background Traditionally, fences, decks, doors, s, cladding and siding are made of components fashioned from solid wood. These products are often considered more tically appealing than those made of metal or cement, for example, metal fences or cement block walls or decks. However, after a period of time, solid wood products may naturally begin to break down from weather exposure and biological infestations. It is known that this deterioration can be ed by ng tile wood witil widely available weatiler resistant coatings, paints, varnishes, finishes and tile like.

Unfortunately, ilowever, treated wood products can often deteriorate within a short period of time requiring partial or complete replacement. Maintenance of many solid wood materials that are suitable for fencing, decking, s and doors is costly. In addition, because of natural ions in wood, replacement of individual components may result in an istent, uneven appearance to the products.

Many products, logies and ideas are used to make extruded or molded thermoplastics as an alternative to wood in semi-structural outdoor applications such as decking, park walkways, children's playgrounds, seats and benches. Tile thermoplastic most widely used is polyetilylene, typically a recycled product from HOPE, LOPE & LLOPE milk bottles, film etc. Other thermoplastics widely used include polystyrene, impact ed polystyrene, PVC and potypropyiene. Many systems aiso use nic ‘r’iiiers such as caicium carbonate, and taic or ceiiuiosic fitter, typicaiiy wood or other naturai , compounded into the thermopiastic to enhance properties and make the compound iook more iike the wooden iumber it es. These systems U} are rapidiy gaining market acceptance, especiaiiy in decks where they have advantages of iong—term durabitity and reduced maintenance. They have an additionai age because oi recent heaith ns regarding the chemicais and preservatives used to treat wood for outdoor appiications and in view of the scarcity oi durabie hardwoods.

Many composites, such as ceiiuiosic/poiymer composites are used as repiacements tor aii—naturai wood, particieooaro, water board, and other simiiar materiai. For exampie, US 3,998,902; US 4,091,153; US 4,686,251; US 4,708,623; US 713; US 5,087,466; US 5,151,238; US 5,417,904; US 5,948,524; US 6,280,667; US 6,827,895 and US 6,936,260 rotate to processes for making piastic/ceiiuiose wood repiacernent products.

Soiid ites ot styrene—mateic anhydride and ased titiers are disciosed in US 934; US 8,894,975 and US 669; Canadian Pubiished Patent Appiication No. 2,626,992 A1 and "Properties oi Styrene— iyiateic Anhydride Copoiymers ning Wood—Based Fiiiers", en et at, Forest Products i, Voi. 48, No. 1, pp. 89—92, January, 1968.

As compared to naturai woods, ceiiuiosicr’poiymer composites otter superior resistance to wear and tear. in particuiar, ceiiuiosic/poiymer composites have enhanced resistance to moisture. in tact, it is weii known that the retention of moisture is a primary cause of the warping, spiintering, and discoioration oi naturai woods. Moreover, ceiiuicsic/poiymer composites have the appearance of nature! wood, and they may be sewn, sanded, shaped, turned, fastened, and finished in the same manner as naturai woods. Ceiiuiosicx’poiymer composites aiso have better e wear resistance than soiio wood, especiaiiy in appiications titre flooring and decking where reguiar abrasion occurs. Consequentiy, ceiiutosic/poiymer composites are commoniy used for appiications such as interior and exterior decorative house moidings, picture Frames, furniture, porch decks, deck raiiings, window moidings, window components, door components, rooting structures, buiiding siding and ciadding, and other suitabie indoor and outdoor components. Furthermore, ceiiuiosic/poiymer composites may repiace highiy durabie and scarce hardwoods, eg. tropical hardwoods.

Those shifted in the art have recognized that excessive moisture content in a U} synthetic wood composition may result in a poor quality end product. in particuiar, excessive moisture content in a synthetic wood composition may result in an end component that is susceptioie to sweiiing, cracking, and crumbling appearance. Consequentiy, it may be necessary to dry osic material to a predetermined ievei prior to introducing it into the synthetic wood composition. Even after the ceiiufosic materiai is dried, it has a naturei tendency to reabsorb moisture from the environment. As a resuit, it may also be necessary to store the dried ceiiuiosic al in a moisture controlfed environment to t the ceiioiosic at from reabsorbing additional moisture before being added to the synthetic wood composition. in iight of these considerations, it may be difficult and costiy to maintain sufficientiy dry ceiiulosic material white shipping it between ent iocations.

Plastic fence components have been deveioped as aiternatives or suppiements to traditionai, naturai wood fences. For example, US 5,100,f09 2t) describes a method of constructing a fence by providing a fiexibie, piastic, roiiabie fence board that can be unroiied and fastened to spaced apart fence posts. The flexible fence board is made with height and width dimensions simulating a standard wooden board and with a iength of 350 feet or more.

According to this patent, the fence board is formed in a continuous extrusion process of a flexible thermoplastic materiai.

US 5,404,685 describes a wait or fence made in part of foamed yrene plastic ents, more icaiiy, piastic coiumns and .

Construction of a fence in ance with this patent requires muitipie steps.

For example, wait or fence stability is achieved by pouring a reinforcing filler material, such as concrete, into a hollow of the polystyrene piastic s after the columns have been secured to the ground. A hardened outer surface of the fence is achieved by applying an or finish, such as stucco or speciai or paint, to the fence or wail after the fence has been constructed.

However, the synthetic wood or wood composite products described above, typioaiiy have disadvantages when their mechanicai properties; aiiy when strength and stittness are compared with the wood they repiace.

Further, the wood/ceiiuiosic composites bed above are susceptihie to creep when subjected to continuous toads and/or high ambient temperatures.

U} Additionaiiy, these materiais tend to warp aher tong term re to heat. e of these structured iimitations, the use of the synthetic wood products described above is often restricted to iess structurai appiications. For exampie, in decks they are used for deck boards but typicaiiy cannot be used for the verticai posts and joists that bear the toads oi the whoie structure.

However, compared to products made of thermopiastic poiymers, which iiy have a high coefficient of thermal ion, wood/ceiiuiosic ites generaiiy have ed thermai stabiiity. Pure thermopiastic poiymers have a high ievei oi thermai expansion. The uction of iignoceiiuiosic fiber to the potyrner reduces the thermai expansion coetiicient.

US 8,221,663 describes a method of making foamed articies having a density oi not more than 1.3 g/cm3.

One probiem rotated to methods for preparing poiymer—wood compositions is 2t) to ensure that the conditions are such that artioies with desired properties, such as thermopiastio weidaioiiity, can ice achieved. in some embodiments, it is important to be slots to obtain symmetricai artistes having tine detaits and speciiic proiiies and shapes. A further probiem s to ensuring that a sutticientiy high proportion of ceiiuiosic fiber can be used, yet resuiting in an articie with the desired properties.

Thus, there is a need in the art to e composite materiais and composite product that overcome the above—described prohiems, as weii as methods oi making such composite materiais and composite products.

Summary of the invention it is an objective of the present invention to provide a composite materiai comprising oeiiuiosic fiber having ed properties, such as improved strength and stittness properties as wet! as iow creep.

Another object of the present invention is to provide a composite product comprising such a composite materiai.

These objectives and other advantages are ed by the t U} invenhon.

The present invention is directed to a composite materiai comprising at ieast % icy weight of a ceiiuiosic materiai, at toast 1% by weight and toss than % by weight oi e maieio anhydride and irom 5% to 50% try weight of a high impact poiystyrene. in one embodiment of the t invention, the composite materiai may comprise other iiiiers such as caioium carbonate and other inorganic tiiiers.

The oeiiuiosic materiai may be thermaiiy modified ceiiuiosic materiai. The i modification is carried out by heat treatment, preteraioiy at a temperature between 130—25Q°C, preterabiy between 20023058 at atmospheric re or at a ature above 120%) at an eievated pressure according to s known in the art.

The composite materiai comprises at ieast 29% by weight oi ceiioiosic materiai, preteraoiy between 25—75% by weight and even more preterabiy between 406594;, 456584; or between 50—60% by weight of ceiiuiosic materiai. in one embodiment, the composite materiai comprises at toast 2% and toss than 20% by weight, such as from 2% to 15% by weight or from 2% to 10%, % to 16% or 2% to 7% by weight oi styrene maieio anhydride (SMA).

The ceiioiosio materiai may consist of a singie form of oeiiuiosic materiai or for exampie a mixture of ent types of fibers. The ceiitiiosic materiai may for e he provided in the term of wood partioies or puip. Exampies oi puip inoiude meohanioai poip, semt~meohanicai or ohernioai puip, such as thermomeohanioai poip, hermomechanioai onto or chemioai puip (manufactured in the Kraft or suiiite process} or dissoiving puip. The wood partioies may for exampie be ground wood, wood tioor or sawdust. The oeiiuiosio materiai may be compacted before being used to prepare the composite materiai according to the present invention: The oeiiniosio materiai may have a particie size beiow 1 mm, abiy heiow (150 mm and even more oreterebiy beiow 025 mm or beiow 0.1 mm. it is preferred that the ceiioiosic meteriai hes a smaii size since a more even U} dispersion and distribution of the ceiioiosic materiei in the composite meteriei is ed. if the ceiiuiosic meteriai is in the form of ceiiuiosic fibers, the fibers preterebiy has a tiber iength beiow 1 mm, ereierebiy beiow 0.50 mm and even more ebiy beiow 025 mm or heiow 0.1 mm.

The oeiiuiosic materiai may be in the form of a powder. Thus, the ceiiuiosic materiai may comprise oeiiuiosic tibers that have been mechanicaiiy treated to produce a powder, The size of the ceiiuiosic materiei is of importance to be abie to obtain a composite ai where the ceiiuiosic materiei is eveniy distributed. it has been found that it the ceiiuiosio meteriai is in the form of a powder it is easy to achieve a good dispersion and mixture with the ooiymer, The high impact poiystyrene (HEPS) can be tor examoie a graft copoiymer ot wherein ooiybutadiene has been added during poiymerizetion to become chemiceiiy bonded to the ooiystyrene end which has subsedtientiy been mixed with normai poiybtrtadiene. HEPS is commeroieiiy eveiiebie, tor exempts under the name Bextrene.

The Sit/EA (styrene meteio enhydride) is a synthetic poiymer that is buiit do of styrene and maieic enhydride monomers.

The present invention atso reiates to a process for ing a composite product which process comprises the steps oi: providing a ceiiuiosio meteriei, high impact ooiyetyrene (HiPS) and styrene maieic anhydride (SMA), feeding said oeiiuiosic ei, REPS and SMA to an extruder and extruding the composite t.

The temperature used in the extruder is oretereioiy above tense.

Betaiied description The present invention reiates to a composite material comprising ceiiuiosio materiai, high impact poiystyrene (HiPS) and styrene maieic anhydride (SMA). it has surprisingiy been tound that the ite materiai according to the present invention provides enhanced strength and stiffness properties.

The s abiiity ot the ite materiai according to the present invention is suitabie for high strength composite es for appiications such as windows and doors and heavier infrastructure appiications where normai wood—poiymer composites and piastics are not suitabie.

The improved strength and stahiiity observed is enhanced by an esteritication reaction between the ceiiuiosic materiai and matrix components. in one embodiment of the t ion, the gravimetrio density of the composite materiai and composite t is higher than 1.0 g/cm3, such as higher than 1.3 g/crriS. rmore, by using thermaiiy moditied osic materiai in the composite, it has been found that a composite having particuiariy ageous strength properties is achieved.

With thermaiiy modified osic materiai, it is meant that the oeiiuiosic materiai has been thermaiiv treated at an increased temperature between {\3 UT tad—2506C, at atmospheric pressure or at a temperature above 120°C at an eievated pressure of above 1 bar. The osic material can be thermaiiy treated ceiiuiosic fibers of any kind of ceiiuiosic wood materiai. The thermaiiy modified oeiiuiosio fibers may be further treated to form said thermaiiy modified ceiiuiosic material, eg. mechanicativ treated and/or chemicaiiy treated. The mechanicai treatment oi the thermaiiy d ceiiuiosic fibers may be done to form a powder and one of the advantages with mechanicaiiy treating thermaiiy modified ceiiuiosic fibers are that they easiiy break into very smaii particies with unique shape. Size and shape are key parameters influencing numerous composite properties, such as strength and water uptake. Because of the very fine ie size and tack of resin compared to what is found in normai dried wood the risk of fiber bundling is grea‘tiy reduced when adding the thermaiiy modified ceiiuiosic material to the poiymer to form the composite materiai, which in turn ieads to more even dispersion and distribution. Chemicai treatment oi the thermaiiy treated osic fibers may he done to improve the reactivity of the materiai. it may aiso be possibie to thermaiiy treat ceiiuiosic tibers that have been mechanicaity or chemicaiiy U} treated, eg. to thermaiiy treat ceiiuiosic fiber that have been ground into a The composite materiai may aiso comprise additives that wiii e the performance and process parameters of the composite. Possibie ves may be iubricants, coupting , pigments, uv-stabiiizers or biockers and/or fitters. in one embodiment of the t invention, the composite materiai comprises a tiame retardant.

The present ion aiso reiates to a process for producing a composite product which process comprises using an extruder to manufacture the ite product. it is possibie to use any kind of extruder.

The composite materiai according to the present invention may tor exampie be produced in the form oi peiiets or granuies, using a compounding extruder.

Such peiiets or granuies can be used to manutacture a composite t comprising the composite ai. Such composite products can for exampie be manufactured by extrusion, injection moutding, rota mouiding, 3D printing or term pressing. The composite materiai may aiso be produced in the term of a shaped composite product, for example by providing a e die through which a shaped composite product is extruded. Such profited composite products may he ed in variety of shapes and tor muitipie purposes.

The produced composite product can he used tor the production oi many different products, such as ciadciing, decking, window and door protiies, tight poies, jetties, joinery, furniture etc. The produced composite products may be used tor appiications such as interior and exterior decorative house moidings, picture frames, iurniture, porch decks, deck raiiings, window moidings, window components, door components, rooting structures, ouiiding siding and ng, and other suitabie indoor and outdoor components. The composite materiai and composite products according to the t invention may aiso be useiui in g as wet! as in marine environments such as submerged structures. Furthermore, ceiiuiosic/poiymer composites according to the present invention may repiace highiy durabie and scarce hardwood, eg. tropioai hardwood.

U1 Exampies Abbreviations: SMA: e maieic: anhydride (Xiran irom Poiyscope) TW: thermaiiy modified ceiiuiosio meteriai HiPS: high impact poiystyrene MOE: moduius oi eiasticity STD: standard deviation WPC: wood—peiymer composite Avg: average CQV: coefficient of variance Examate 1 in this ment, the mechanicat properties of composite products sihg a composite material accerdirig to the t invention were investigated.

Thermaiiy modified wood (HTW) fibers were used. The fibers were shavings from pine that had been tiy modified by heating to 212°C for 3 hours and subsequentiy ground in a hammer miii and passed through a screen.

The toiiowing formuiatioris where prepared: Tabie t. Formota’tiehe 0t gametes, % by weight.

Content of SHEA eenterrt HEPS content cettuiesic matertei Pine 50% 0% SMA-(3% TW 50% 0% SMA2.5% "WV 50% 25% 47.5% % TW 53% SMA'10.0% TW 50% . . % The specifications at the pitet extrusion system were as e: with the ihg process parameters used in the extruder: Tahie 2K Extrusion parameters, Woedtruder equipment. The eetiuteeic fibers were direct ted to the twin screw and the SMA was added via the eirtgie it) screw. Decking board eorrrposite producte were produced. mmwaaau-naz The tiexurat properties (ttexurat strength and tiexurai medutus) were determined for the samptes: Tehie 3. Fflexurafl properties of eamoies end control/comparative sampies.

Strength AVZrage Avearage Gontroi——pine :31. ()7 E1 36 4688 _ SMA0% 31.26 E1. 17 5849 SMA2.5% SMA—5% SMA7.5% 5026 E11 .80 e431 — SMA10% 5029 E199 6110 Six/1A12_5_%___ SMA15% Foemed Commerciaiiy avaiiehie * data from g board sempies made of em SMA and pine wood; wood content 30% and specific gravity was 0.85 ** oommeroiafliy avaiflabie product (poiypropyiene/poEyethyiene and 513% by weight of normal sawdust); date from technical! data sheet of oommeroieiiy evaiiabie WPC Examgie 2 The dimensionai stabéiéty of the samoies was determined.

The sempiee were first conditioned at room temperature and then immersed into water for a tote! of 28 days. The dimensionai measurements were conducted at 24 hours, 7 days, 14 days, 21 days and 28 days for the water absorption and dimensionai s of width, iength and thickness.

Tabie 4. Weight gain percentage of the s soaked in water. ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ 1.181 €8.54 51.222 8.87 8.888 15.87 8.881 18.8 8.817 8.85 0.884 8.82 ........................................................................................................................................................................................................................

........................................................................................................................................................................................................................ Tabie 5. ionai change (thickness sweiiing), percentage. sampias saaked in water. 00v Avg 5000 12.420 0742 SMA 25% 10.440 50.512 5545 5% 0.750 E0.550 5745 7.5% 8.470 30.517 SMA10% 77.580 50.553 SMA 0.420 18.240 0.540 12.5% 55451570 0.552 1030030582 0.515 8.416 05505:— 1011 5.450 @1515 1.838 5.550 F3305 $501835 __ 285575 875.50% 0.050 51.041 55.85 WNW -10750‘3’7501963 5545 10% 72.770 0.758 SMA 8.080 0.780 1 2. 5% 5MA15% 0.550 0.500 50.728 GOntroi— 2.150 8.440 @2245 it was found that the 55.010355 with tharmaily modified ceiiuiosic materiai had E035 water absorption (weight gain} and dimangionai s compared 0) the sampie made with reguiar pine.

The content of Sir/EA eignificentiy affected the water absorption (weight gain) and dimensionai s at the sample.

Examgie 3 The coefficient of tnermei expaneicn (GTE) was determined in ance with ASTM Standard [3 696 and compared to other tionei piestic end compesite products. The GTE is measured tor two directions, iengthwiee (extrusion direction) and widthwise (cross direction to the ion).

Tehie 6. CTE veiues of the eempiee Sampie GTE 3...................................

Centrei—pine—iength 2.76 E435 5‘15 E—06 18.71 Centrei—pine—width 6.96 E—OS 2.23 E437 0.32 SMA—O‘fii—iength 4.86 E~05 3.65 508 7.51 ..........................................................................................................................................................................................................

SMA—Q%—widih 6.94 E305 3.07 E436 4.42 SMA—Efi‘E/ouiength 32.40 E—05 2.13505 8.88 SMA—2.5%~width 36.62 505 2.16506 3.26 SMA50/ieng1h251505 _3;?_i___§_:£i§__________ t)%—width 36.68 are 7.81 52-07 SMA—7.5%-Eength 2.30 EOE 9.57 1-3—08 0.42 SMA-7.5%—width 6.85 E-OS 1.32 E3063 1.98 SiiAA—iG%—iengiii 2.29 5-05 5.74 307 SMA—TDO/(a—widih 6.72 5-05 4.77 E-G? SMA-12.5%-iength 2.92 E-OS 2.16 E~O7 1.07 SMA*12.5%-Width 6.47 E~05 1.15 E—OB 1.77 SMA-‘ifi‘t’o—iength 32.07 E—ee 1.75 we .........................................................................................................................................................................................................3 SMAm15%~width 6.46 E—OS 3.48 EvOE PVC proiiie‘" * the CTE vaiue of the PVC es is assumed being iengthwise expansion tiniees the manufacturers mention the expansion direction. ** the GTE vaiue of a eemn‘terciaiiy avaifabie WPC is assumed to he iengthwise expansion it was found that the sampies according to the present invention showed coefficient of thermaf expansion simiiar to commerciaify avaiiabfe WPC and about 50% of a PVC erotite which is a ma§or advantage. it was found that the GTE for extrusion (iengthwise) direction is much less than cross (widthwise) direction. it was found that the sampies with thermaiiy modified ceiiuiosic materiai showed tower CTE vaiues than with the nerrnai pine. it was found that the content at SMA contributed to tower GTE of the s.

Examgie 4 A study was carried out it) estimate the teasihiiity of painting on the surfaces :20 at eernposite products aeserding te the present invention.

The teiiewing sampies were prepared (weight—9'5): HiPS-TW-WPC—SMA HiPS 47.5% with TW Cut from g 2.5% 50% / SMA 2.5% boards W-WPC—SMA HiPS 45% with TW 50% Out from decking .0% /‘ SMA 5.0% boards i0% /‘ SMA 10% boards HiPS 35% with rw 50% Cut irom g % /‘ SMA 15% boards SMA: styrene maieic anhydride (Xiran from Peiyseope) TW: thermatiy mediiied eeiiuiesie materiai if) HiPS: high impact pofystyrene (*imThe fibers were shavings from pine that had been iiy modified by heating to 212°C for 3 hours and subsequentiy ground in a hammer rniii and passed through a screen.

U} The painting/coating conditions were as ioiiows: Paint brand NuCoat water~based Paint product name Super anti~heat Signai Biaok & Bar Res! Surface preparation Scrapped with Scotch Brits and wiped down with Zowo-Piast 1120 or used as suppiied Spray rate Spray booth 75° with 1,8 nozzie size Spray pressure 55 psi Room condition Room temperature under RH 39% Cure temperature 90.5°F with RH 21% Cure tirrre 24 hours Test method: ASTM @4541, Standard test method for puiiuoh‘ strength oi coatings using le adhesion testers, was used. The portahie on tester was a puii~oif tester, Modei PosiTest AT—M front ho.

The toiiowing resuits were obtained: Average r stress H1135TW:WPCSMA1%.59’9" H1133TW—WPC—SMA 5(3% "512"ps1m HiPS—TW—WPC—SMA 10% 355 psi HiP‘STWWPCSMA 15% 373 psi The puii—oit test was conducted on the hard surfaces with and without treatment to evaiuate the tepoiogicei properties of the sampie surfaces. The surface treatment was conducted by scrubbing the surface using Scotch Brite® s and wiped down with Zowo—Piast 1120, a water— based/biodegradabie oieaning agent for cieaning and preparing prior to ooaflng.

The ing reeutte were ebteineci tor the d surfaces: Average putt—eff stress HEPS—TW—WPC—SMA 2.5% 555 psi HiPS—TW-WPC—SMA 5.0% 453 psi HiPS—TW—WPC-SMA i0% HEPS—TW—WPC—SMA 15% The putt-cit stress of att eamptee are very high which represents the painting— ebitity of the composite products according to the present invention. As ehown above, the SMA t and the surface treatment attect the bending strength. in view of the above detaited description ot the ereeent invention, other mediticatiens and variations wiit become apparent to these ekitted in the art.

Hewever, it eheuid be apparent that such other cations and variations may be effected without departing from the spirit and scope of the invention.

I/WE

Claims (13)

CLAIM :

1. A composite material comprising at least 20% by weight of a osic material, at least 1% by weight and less than 20% by weight of styrene maleic anhydride and from 5% to 50% by weight of a high impact polystyrene, wherein the cellulosic material is a thermally modified cellulose material which has been thermally modified by heat treatment at a temperature between 160-250°C, such as between 200-230°C, at atmospheric pressure or at a temperature above 120°C at elevated pressure.

2. The composite material according to claim 1, wherein the ite material comprises from 2% to 15% by weight of styrene maleic anhydride.

3. The composite material according to claim 2, wherein the composite material comprises from 5% to 10% by weight of styrene maleic anhydride.

4. The composite material according to any one of claims 1-3, comprising 25- 75% by weight of a cellulosic material.

5. The composite al according to claim 4, comprising 40-65% by weight of a cellulosic material.

6. The composite al according to claim 5, comprising 45-65% by weight of a cellulosic material.

7. The composite material according to claim 6, comprising 50-60% by weight of a cellulosic material.

8. The composite material according to any one of claims 1-7, comprising 35- 50% by weight high impact yrene.

9. The composite material according to any one of claims 1-8, wherein the cellulosic material has a le size below 1 mm.

10. The composite material according to any one of claims 1-9, wherein the cellulosic material is in the form of a .

11. A composite product comprising a ite material according to any one of claims 1-10. AH26(37889256_1):AXG

12. Use of the composite product according to claim 11 for cladding, decking, window and door es, light poles, jetties, joinery or furniture.

13. Process for producing a composite t which process ses the steps of: a) providing at least 20% by weight of a cellulosic material, from 5% to 50% by weight of a high impact yrene (HIPS) and at least 1% by weight and less than 20% by weight of styrene maleic anhydride (SMA), wherein the cellulosic material is a thermally modified cellulose material which has been thermally modified by heat treatment at a temperature between 160-250 °C, preferably between 200-230 °C at atmospheric pressure or at a temperature above