WO2002064670A1

WO2002064670A1 - Polymer composite product, a process for the manufacture thereof and use of the product

Info

Publication number: WO2002064670A1
Application number: PCT/DK2002/000085
Authority: WO
Inventors: Tom Løgstrup ANDERSEN; David Victor Plackett
Original assignee: Riso National Laboratory
Current assignee: Riso National Laboratory
Priority date: 2001-02-09
Filing date: 2002-02-07
Publication date: 2002-08-22
Anticipated expiration: 2003-08-09

Abstract

The invention concerns a polymer composite product with improved properties manufactured from a lay-up comprising (a) a core fibrous reinforcement material consisting of one or more layers of natural fibers, covered on each side with (b) a compatibiliser sheet or foil effecting an in situ compatibilisation of the natural fibres and the thermoplastic matrix material, and on top of the compatibiliser foil (c) one or more sheets or foils of a thermoplastic matrix material, said lay-up being subjected to an elevated temperature followed by cooling under pressure to produce a composite product. The invention further concerns a process for the manufacture of said product and the use of the product in the industry, such as the automotive industry, the building industry, the furniture industry and the windmill industry. The present invention provides a number of advantages over the prior art, including one step in situ compatibilisation of fibre mats, improved processing flexibility for the manufacturer, easy handling/automation of compatibilisation treatment and lay-up process and a better performance of the composite material.

Description

Polymer composite product, a process for the manufacture thereof and use of the product

Field of the Invention

The present invention relates to a process for the manufacture of a polymer composite product with improved properties, said product consisting of a thermoplastic matrix material reinforced by one or more layers of natural fibres, optionally blended with synthetic fibres, in which the fibres are in the form of woven or non-woven mats or filament- wound fibre yarn, whereby the fibres are placed between layers of the matrix material, each layer comprising at least one sheet or foil of the matrix material, where- after the lay-up is subjected to an elevated temperature followed by cooling under pressure to produce a composite product. The invention also relates to said polymer composite product manufactured by the process and to the use of the product within definite fields of industry, such as the automotive industry, the building industry, the furniture industry and the windmill industry.

Background of the Invention

There is an increasing interest worldwide, especially in Europe and North America, in the development of new composite materials based on combinations of thermoplastics with plant fibres as reinforcement. This interest is driven by a number of factors related to the replacement of synthetic and inorganic fibres (e.g. glass fibres) in a variety of products. The advantages of using plant fibres in comparison to glass fibres include the facts that:

• plant fibres come from renewable resources and their availability is more or less unlimited

• composites reinforced by plant fibres are arguably CO_*-neutral • plant fibres present processing advantages because they are much less abrasive than glass fibres

• plant fibres have advantages over glass fibres in terms of health and environ mental issues during processing

• unlike glass fibre composites, plant fibre composites can readily be burned to create energy at the end of the useful service life of the product, and

• plant fibres in combination with biodegradable polymers can provide fully biodegradable composite materials.

One of the most important challenges in the development of plant fibre-reinforced composites has been the need to compatibilise fibre and polymer surfaces in order to optimise the properties of the composite. This results from the very different nature of the hydrophobic (i.e. water repellent) polymer surfaces and the hydrophilic (i.e. water attracting) surfaces of plant fibres. Much research has already been devoted to this topic and the use of commercially available compatibilising agents is well known. The most widely studied compatibilising agent has been maleic anhydride-modified polypropylene, otherwise known as maleated polypropylene or MAPP, that has been used to compatibilise plant fibres with polypropylene (PP).

The use of compatibilising agents, such as MAPP, in the compatibilisation of fibres and thermoplastics during the fabrication of polymer composites is well known per se. For example, EP 0 201 367 Bl discloses a fibre-reinforced thermoplastic polymeric composite material and a second thermoplastic polymer (different from the first one, but compatible with it) placed between the first polymer and the fibres, which are predominantly glass fibres. This second polymer promotes the wetting of the mineral fibres. According to WO 00/00351, a bonding agent in the form of a web-shaped non- woven material is continuously inserted between a plastic web and a web of reinforce- ment glass fibres, and the joined webs are fused using the effects of pressure and temperature. The bonding agent is maleic anhydride in the form of a non- woven made up of a number of extruded, non-needled individual fibres. Also an article by K.-P. Mieck et al, Polymer Composites, Vol. 17, 873-878 (1996), describes the use of compatibili- sers, such as polypropylene functionalised with maleic anhydride, to treat natural fibres, specifically flax fibres, thereby obtaining products capable of competing with traditional glass fibre-reinforced products.

Heretofore, the MAPP polymer has predominantly been used in the form of an additive for the treatment of fibres, for example during extrusion processes. While such treatments lead to products with adequate properties for many purposes, an alternative, simple and versatile method of compatibilisation would expand the range of process options available for high-performance plant fibre composites.

Brief Description of the Invention

The present invention is based upon a specific use of compatibilising agents, e.g. MAPP, in the form of a sheet, a foil, a fabric or the like in combination with plant fibres to produce composites with optimum properties, especially with regard to tensile strength. In particular, the key point is to use the compatibihser foil at the interface between the fibres in mat form or another suitable form (e.g. unidirectional yarn lay-up) on the one hand and the polymer (e.g. polypropylene) in the form of foils on the other hand. The result is an in-situ compatibilisation during the composite fabrication rather than a separate step involving the above-mentioned addition of the compatibihser to the fibres or to the polymer prior to the final manufacturing step. This approach will be extendable to a wide variety of fibre/polymer/compatibiliser combinations.

More specifically, the present invention relates to a process for the manufacture of a polymer composite product with improved properties, said product consisting of a thermoplastic matrix material reinforced by one or more layers of natural fibres, in which the fibres are in the form of woven or non- woven mats or filament- wound fibre yarn, whereby the fibres are placed between layers of the matrix material, each layer comprising at least one sheet or foil of the matrix material, whereafter the lay-up is subjected to an elevated temperature followed by cooling under pressure to produce a composite product. The process of the invention is characterised in that the fibrous sheet and the matrix material are compatibilised in situ by means of a layer of a compatibihser material, said layer being in the form of a sheet, a foil, a fabric or the like, placed in between the fibrous material and the matrix.

The thermoplastic material is preferably polypropylene (PP), but other thermoplastic materials are useful as well, e.g. polyethylene, polystyrene, polylactide, polyhydroxybutyrate, co-polyethyleneterephthalate and polyethylene/polypropylene copolymers.

An example of the use of a preferred compatibihser material is maleated polypropylene (MAPP) or a blend of MAPP with polypropylene in combination with polypropylene as the matrix material. Other preferred compatibihser materials are selected from the group consisting of a maleated polyethylene (MAPE), a maleated polylactide, a maleated polyhydroxybutyrate and a maleated polystyrene in the form of foils used in combination with polyethylene, polylactide, polyhydroxybutyrate and polystyrene, respectively.

The fibrous reinforcement in the composite product manufactured by the process of the invention consists of either:

[1] plant fibres selected among jute, hemp, flax, wheat straw, kenaf, sisal and coir;

[2] wood or cellulose fibres;

[3] blends of the natural fibres mentioned in [1] and/or [2], or [4] blends of natural fibres with synthetic fibres.

The synthetic fibres may be any kinds of artificial or chemical fibres, including e.g. polypropylene (PP), polyethylene (PE), PP/PE copolymers, glass, aramid, carbon etc.

The invention also concerns the polymer composite product perse manufactured by the inventive process from a lay-up comprising:

(a) a core fibrous reinforcement material consisting of one or more layers of natural fibres, covered on each side with

(b) a compatibihser sheet or foil effecting an in situ compatibilisation of the natural fibres and the thermoplastic matrix material, and on top of the compatibihser foil

(c) one or more sheets or foils of a thermoplastic matrix material, said lay-up being subjected to an elevated temperature followed by cooling under pressure to produce a composite product.

The present invention provides a number of advantages over the prior art, including:

• One step in situ compatibilisation of fibre mats • Improved processing flexibility for the manufacturer

• Easy handling/automation of compatibilisation treatment and lay-up process

• Better performance of composite material

As already mentioned, the process and the products according to the invention will find use within a number of different fields of industry. One of the key areas will be the automotive industry. In Europe the automotive industry has taken a major lead in using plant fibre composites in automotive interiors. The industry has been particularly interested in the environmental advantages of such composites, as requirements for eventual disposal or recycling of car components become still more stringent. The weight and cost advantages of these composites are also particularly important to the industry.

In North America, although the automotive industry has been rapidly catching up with Europe in terms of the use of plant fibre composites in car interiors, it appears that the building product sector there has been more active and has established a rapidly growing demand for decking, for example, based on extruded plant fibre-reinforced thermoplastics. Such products are sold as maintenance-free materials to compete with preservative-treated or naturally durable wood decking. Future opportunities for plant fibre composites are thought to exist in the furniture industry and in the windmill industry.

The main benefit of the technology that forms the basis of the present invention in contrast to the known techniques is the ability to maximise the key mechanical properties (e.g. tensile strength) in "one shot" through a film-stacked lay-up technique. Although this is practised by hand in laboratory scale, the process will be amenable to semi-continuous application through feeding of polymer and compatibihser films in-line with fibre mats to provide the required sandwich lay-up. As stated above, the placement of the compatibihser directly at the fibre/polymer interface is the main feature of the inventive technology.

Brief Description of the Drawings

The invention will be described in further details in the following with reference to the accompanying drawings, in which:

Fig. 1 is a schematic view of the composite lay-up;

Fig. 2 is a diagram showing the influence of the compatibihser location on the resulting tensile strength; Fig. 3 is a graph showing the tensile strength as a function of the MAPP content for a product according to the invention comprising a random jute fibre mat, and

Fig. 4 is a graph showing the tensile strength as a function of the MAPP content for a product according to the invention comprising a random wood/binder fibre mat.

Detailed Description of the Invention

As previously mentioned, the present invention is based upon a specific use of compatibilising agents, e.g. MAPP, in the form of sheets, foils, fabrics or the like in combination with plant fibres to produce composites with optimum properties, especially with regard to tensile strength. More specifically, it has surprisingly been found that the exact location of the compatibihser, e.g. MAPP, relative to the fibrous material is of utmost importance, and therefore the fibrous sheet and the matrix material are compatibilised in situ by means of a layer of a compatibihser material, said layer being in the form of a sheet, a foil, a fabric or the like, placed in between the fibrous material and the matrix.

The polymer composite product according to the present invention consists in principle of a large number of reinforcing fibres, e.g. jute fibres, held together by a thermoplastic matrix material, e.g. polypropylene (PP). It is primarily the reinforcing fibres which give the composite product its desirable properties, whereas the matrix material must be capable of distributing any strains equally between the fibres. The adhesion or bonding between the fibres and the matrix material is therefore crucial to the properties of the product.

The typical lay-up (film stacking) used in the invention is known perse. As an example, the lay-up may consist of a stack of fibre sheets, e.g. jute, said stack being covered on each side by a sheet or foil of a compatibihser, preferably MAPP, said sheet or foil in turn being covered by one or more layers of a matrix material, preferably PP. The lay-up is heated under vacuum in contact with the heating elements, causing the PP matrix material and the MAPP interface foil to melt, thereby wetting the jute fibres.

The lay-up is subsequently cooled under pressure (consolidation) whereby the plastics solidify, leading to the formation of the desired composite material (a laminate).

It is very important that the MAPP foil is placed directly in contact with the stack of fibre sheets, because it is the maleic anhydride (MA) part of the MAPP which is capable of establishing a strong chemical bonding to the fibres, thereby providing an improved bond/compatibilisation between the reinforcing fibres and the PP matrix material.

A number of working experiments have been performed, showing that an unambiguously positive effect is obtained by using MAPP as a compatibihser foil for in situ compatibilisation. These examples, illustrating the practical working of the invention, include experiments with products containing jute or wood fibres bonded together by means of a polypropylene (PP) matrix material and varying amounts of MAPP.

Figs. 3 and 4 show the tensile strength vs. the MAPP content for a jute fibre mat and a wood/binder fibre mat, respectively. A MAPP content of 0 % (w/w) corresponds to the starting material.

It appears from the figures that tensile strengths 30 - 50 % above those of the reference material may be obtained by using a MAPP foil as an in situ compatibilising agent.

Examples

Experiments were undertaken in order to determine the effect of MAPP film location, percentage of MAPP in the composite lay-up, and MAPP type on the tensile properties of the resulting composites. The experimental procedure involved the setting up of a sandwich construction based on natural fibre mats placed between layers of polymer film. This lay-up was processed using a rapid press consolidation technique and converted into fibre/polymer composite panels. These panels were cut into sections using a standard pattern and samples were tested for tensile properties as well as for porosity. Details of the experiments are described in the following sections.

Materials

a) Fibre mats

The fibres used in the experiments were either jute or mixed softwood in the form of mats. A needle-punched jute mat was obtained from JB Plant Fibres Ltd., UK, and an air-laid mat was prepared from mixed spruce and pine wood fibres using a Dan- Web machine. The wood fibre mat contained 9 % (w/w) of a commercial bicomponent polypropylene (PP)/polyethylene (PE) fibre as a binder. The basis weight of the jute mat was 250 g/m² and that of the wood fibre mat was 300 g/m² under ambient laboratory conditions. The moisture content of the mats under these conditions was in the range 8 - 10 % (w/w).

b) Polymer films

Commercial samples of PP and maleated polypropylene (MAPP) were extruded into films using a Haake single-screw extruder.

The PP selected for the experiments was Dow Inspire H710-05, a general purpose inj ection-moulding grade homopolymer with good flow properties and a melt flow index of 6.0 as measured by ISO standard 1133. Temperatures in the extruder were set at 160 °C at the inlet, 180 °C in the first section of the extruder barrel, 200 °C in the second section of the extruder barrel, and 200 °C in the extruder die. The roll temperature was set at 65 °C. PP films were extruded with thicknesses in the range 0.15 - 0.25 mm and a width of approximately 120 mm.

The MAPP product Polybond 3002 was obtained from Uniroyal Chemicals; this product was used for most of the experiments. This grade of MAPP has a melt flow index in the range of 7.0 - 12.0 dg/min, a MAH index in the range 0.5 - 0.8 and a maximum moisture content of 0.1 % as supplied. Extruder temperatures were set at the same values as those used for extruding PP. The roll temperature was reduced to 55 °C to optimise film quality. Film thicknesses and width were the same as for the PP films. Another MAPP product, Fusabond MD 51 ID from DuPont, was also used in the experimental series. The extrusion temperatures for Fusabond were the same as those used for Polybond 3002, but the roll temperature was increased to 65 °C to obtain the best film quality.

Process

a) Lay-up

Composite lay-ups were prepared by sandwiching a number of fibre mat layers between layers of PP film. Films of MAPP or MAPP/PP blends were then placed at the interface between the jute fibre mats and PP films. Typically,five layers of jute mat were used with five to seven layers of PP film on either side. Knowing fibre and polymer densities, the ratio of fibre weight to polymer weight was chosen so as to achieve a targeted fibre weight fraction of 40 % or a fibre volume fraction of 30 %. In the case of the wood fibre mats, films of MAPP or MAPP/PP blends were placed between the fibre and the PP films or were interspersed between layers of PP film and jute mats in a multi-layer construction.

The fibre mat/polymer film lay-ups were placed carefully between Teflon release foils and secured in a metal frame. The frame was then used to convey the lay-up into the press. The importance of placing the MAPP film at the fibre mat/PP interface was demonstrated by preparing a number of lay-ups in which the compatibihser film was placed either at the interface (as shown schematically in Fig. 1), in the middle of the layer of PP films, or at the top and bottom surfaces of the entire lay-up.

b) Composite production

A rapid press consolidation method was used to produce composite panels for testing purposes. This method has been described previously [Andersen, T.L. (1997): Proceedings of the 18th Risø International Symposium on Materials Science: Polymeric Composites - Expanding the Limits; Eds. Andersen, S.I.; Brøndsted, P.; Lilholt, H; Lystrup, Aa.; Rheinlander, B.F.; Sørensen, B.F. and Toftegaard, H., Risø National Laboratory, Roskilde, Denmark] and involves pre-compression of each lay-up followed by heating under vacuum for 10 minutes. The frame was then rapidly transferred back to the press and the lay-up was consolidated for one minute at 30 °C. Specific details of the composite production process were as follows:

• Pre-compression for 30 seconds in the pressure range of 2.2 - 3.3 MPa.

• Contact heating of the pre-compressed lay-up at 190 °C under minimum vacuum of approximately 4.0 mbar for 10 minutes.

• Rapid conveying of the lay-up to the press section in which it was consolidated at 30 °C and at a pressure in the range of 2.2 - 3.3 mPa for one minute.

Testing

Composite panels were cut into sections allowing for at least three tensile test specimens in each case. The specimens were dogbone-shaped, measuring 180 mm in length, 25 mm in maximum width and 15 mm in minimum width. In the case of the jute composites, samples for tensile testing were cut both in the direction in which the mat was formed and in right angles to this direction. These samples were taken because of the known differences in properties of the jute mat in these two directions and were labelled 0° and 90°, respectively. Tensile testing was undertaken using an Instron machine operated in displacement control at a speed of 2 mm/min with a 5 kN load cell. The longitudinal strain of each specimen was recorded with two back-to-back extensometers. Readings of load and strain were sampled at 4 Hz with a PC-based data acquisition system. The average strain was used and the stress was calculated as load divided by initial cross- section. The results were expressed as plots of stress (MPa) against strain (%). The ultimate tensile strength or tensile strength at yield and the tensile stiffness, as determined by the slope of the tangent to the stress-strain curve drawn through the origin, were established from the stress-strain plots.

The fibre volume fraction and the porosity of the composite samples were determined by gravimetric measurement using a slightly modified version of ASTM Standard D 3171-76.

Results

Influence of MAPP location

The results of tests to determine the tensile properties of the jute fibre/PP composites without MAPP and with MAPP added at three different locations in the lay-up are shown in Table 1. Tensile strength values varied according to MAPP location in the range of 40 to 60 MPa. The highest strength value was obtained when MAPP was located at the fibre/PP interface (Fig. 2). Composite tensile stiffness was not significantly influenced by MAPP location in the lay-up. Influence of MAPP content

The results of tests to determine the tensile properties of the jute and the wood fibre composites as a function of the MAPP content are shown in Tables 2 and 3. Tensile strength values increased with increasing MAPP content as shown in Fig. 3 and Fig. 4. Composite tensile stiffness was not significantly influenced by the MAPP content in the lay-up.

Influence of MAPP type

The results of tests to determine the tensile strength of jute composites prepared using Polybond 3002 or Fusabond MD 51 ID are shown in Table 4. The increase in composite tensile strength as a result of placing the MAPP film at the fibre/PP interface was achieved with either type of MAPP. Composite tensile stiffness did not significantly vary with MAPP type (Table 4).

Fibre volume and porosity

The measured fibre volume fractions and porosity values are shown in Tables 1-4. In general, the tensile properties of fibre-reinforced composites are affected by changes n fibre volume fraction and porosity; however, the variations shown in Tables 1-4 and especially in Tables 2-3 do not alter the trends in tensile properties described above.

Influence of MAPP in polyethylene composites

The results of tests to determine the tensile properties of jute composites prepared using MAPP (Polybond 3002) in combination with a polyethylene (PE) matrix are shown in Table 5. The relatively low tensile strength and stiffness of PE are dramatically improved by the incorporation of about 40 weight percent jute fibres and these properties are increased even further when a Polybond 3002 film layer is placed between the jute fibre mats and the layers of PE film. This effect is particularly noticeable in the case of tensile strength where an increase of about 50% is achieved through the addition of MAPP compatibihser.

Influence of MAPP in hemp/polypropylene composites

The results of tests to determine the tensile properties of hemp composites prepared using MAPP (Polybond 3002) in combination with a polypropylene (PP) matrix are shown in Table 6. As indicated in the first two rows of the Table, tests on composites prepared using hemp mat samples cut in the direction of the mat roll (0°) or perpendicular to the direction of the mat roll (90°) gave virtually identical average tensile properties. However, as shown in Table 6, the addition of a MAPP compatibihser film between the hemp fibre mats and the polypropylene films resulted in composites with much improved tensile properties. The results indicated an average increase of 45% in tensile strength and an average increase of 17% in E-modulus (tensile stiffness) when compatibihser films were included in the lay-up.

Influence of MAPP in flax/polypropylene composites

The results of tests to determine the tensile properties of flax composites prepared using MAPP (Polybond 3002) in combination with a polypropylene (PP) matrix are shown in Table 7. As indicated in the first two rows of the Table, tests on composites prepared using flax mat samples cut in the direction of the mat roll (0°) or perpendicular to the direction of the mat roll (90°) suggested that the mat may have slightly better mechanical properties in the direction perpendicular to the roll. As shown in Table 7, the addition of a MAPP compatibihser film between the flax fibre mats and the polypropylene films resulted in composites with much improved tensile properties. Averaged over all samples tested, composite tensile strength increased by 47% and E- modulus (tensile stiffness) increased by 13% when compatibihser films were included in the lay-up.

Table 1: MAPP location, Jute/Com atibilizer/PP, Process temperature 180'C, Heat time 10 minutes, Consolidation forceΛem erature/time: 200 kN^O'CAl minute

σ>

CO

Table S; Tensile properties ol PE and jutβ/PE composites

Conclusions

The following conclusions can be drawn from the experiments:

1. The tensile strength of composites prepared from a sandwich-type fibre/polymer lay- up is maximised when a MAPP compatibiliser film is placed at the fibre/polymer interface.

2. Composite tensile strength increases as a function of MAPP compatibiliser content in a sandwich-type fibre/polymer lay-up and reaches a plateau at a MAPP concentration that varies with fibre type and with the construction of the lay-up.

3. More than one MAPP product can be used to achieve the observed increases in composite tensile strength.

4. Composite tensile stiffness does not change significantly when MAPP compatibiliser is incorporated in a composite lay-up.

Claims

1. A process for the manufacture of a polymer composite product consisting of a thermoplastic matrix material reinforced by one or more layers of natural fibres, in which the fibres are in the form of woven or non- woven mats or filament- wound fibre yarn, whereby the fibres are placed between layers of the matrix material, each layer comprising at least one sheet or foil of the matrix material, whereafter the lay-up is subjected to an elevated temperature followed by cooling under pressure to produce a composite product, characterised in that the fibrous sheet and the matrix material are compatibilised in situ by means of a layer of a compatibiliser material, said layer being in the form of a sheet, a foil, a fabric or the like, which is placed on each side of the layer(s) of fibres to separate the fibres from the matrix material.

2. A process according to claim 1, characterised in that the thermoplastic material is polypropylene (PP).

3. A process according to claim 1, characterised in that the thermoplastic material is selected from the group consisting of polyethylene, polystyrene, polylactide, polyhydroxybutyrate, co-polyethyleneterephthalate and polyethylene/polypropylene copolymers.

4. A process according to any of the claims 1-3, characterised in that the layer of a compatibiliser material consists of a maleated polypropylene (MAPP) or a blend of MAPP with polypropylene.

5. A process according to any of the claims 1-3, characterised in that the layer of a compatibiliser material is selected from the group consisting of a maleated polyethylene (MAPE), a maleated polylactide, a maleated polyhydroxybutyrate and a maleated polystyrene or blends of each of these with the matrix polymer (e.g. MAPP/PP, MAPE/- PE) in the form of foils.

6. A process according to any of the preceding claims, c h a r a c t e r i s e d in that the fibrous reinforcement consists of either:

[2] wood or cellulose fibres;

[3] blends of the natural fibres mentioned in [1] and/or [2], or

[4] blends of natural fibres with synthetic fibres.

7. A process according to claim 6, c h a r a c t e r i s e d in that the synthetic fibres are selected among polypropylene (PP), polyethylene (PE), PP/PE copolymers, glass, ara- mid and carbon fibres.

8. A polymer composite product manufactured from a lay-up comprising:

(b) a compatibiliser sheet or foil effecting an in situ compatibilisation of the natural fibres and the thermoplastic matrix material, and on top of the compatibiliser foil

9. The product of claim 8, wherein the thermoplastic material is polypropylene (PP).

10. The product of claim 8, wherein the thermoplastic material is selected from the group consisting of polyethylene, polystyrene, polylactide, polyhydroxybutyrate, co- poly ethyleneterephthalate and polyethylene/polypropylene copolymers.

11. The product of any of the claims 8 - 10, wherein the the layer of a compatibiliser material consists of a maleated polypropylene (MAPP) or a blend of MAPP with polypropylene.

12. The product of any of the claims 8 - 11, wherein the fibrous reinforcement consists of either:

[2] wood or cellulose fibres;

[3] blends of the natural fibres mentioned in [1] and/or [2], or

[4] blends of natural fibres with synthetic fibres.

13. The product of claim 12, wherein the synthetic fibres are selected among polypropylene (PP), polyethylene (PE), PP/PE copolymers, glass, aramid and carbon fibres.

14. The use of the product according to any of the claims 8 - 13 in the automotive industry.

15. The use of the product according to any of the claims 8 - 13 in the building industry.

16. The use of the product according to any of the claims 8 - 13 in the furniture industry.

17. The use of the product according to any of the claims 8 - 13 in the windmill industry.