WO2014076353A1 - A method and a system for manufacturing a composite product and a composite product - Google Patents

A method and a system for manufacturing a composite product and a composite product Download PDF

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Publication number
WO2014076353A1
WO2014076353A1 PCT/FI2012/051111 FI2012051111W WO2014076353A1 WO 2014076353 A1 WO2014076353 A1 WO 2014076353A1 FI 2012051111 W FI2012051111 W FI 2012051111W WO 2014076353 A1 WO2014076353 A1 WO 2014076353A1
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WO
WIPO (PCT)
Prior art keywords
fiber
composite product
product according
fiber fraction
fibers
Prior art date
Application number
PCT/FI2012/051111
Other languages
French (fr)
Inventor
Harri Kosonen
Sami Turunen
Jere SALMINEN
Petri MYLLYTIE
Kari Luukko
Stefan Fors
Original Assignee
Upm-Kymmene Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Upm-Kymmene Corporation filed Critical Upm-Kymmene Corporation
Priority to PCT/FI2012/051111 priority Critical patent/WO2014076353A1/en
Publication of WO2014076353A1 publication Critical patent/WO2014076353A1/en

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L97/00—Compositions of lignin-containing materials
    • C08L97/02—Lignocellulosic material, e.g. wood, straw or bagasse
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/06—Fibrous reinforcements only
    • B29C70/10—Fibrous reinforcements only characterised by the structure of fibrous reinforcements, e.g. hollow fibres
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/58—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising fillers only, e.g. particles, powder, beads, flakes, spheres
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/04—Reinforcing macromolecular compounds with loose or coherent fibrous material
    • C08J5/047—Reinforcing macromolecular compounds with loose or coherent fibrous material with mixed fibrous material

Definitions

  • the invention relates to a method and a system for manufacturing a composite product. Further, the invention relates to a composite product and a use of the composite product. Background of the Invention
  • the composite product may be a final product or an intermediate product.
  • Another object of the invention is to disclose a new method and a system for manufacturing a composite product.
  • the method for manufacturing a composite product according to the present invention is characterized by what is presented in claim 61 .
  • the composite product according to the present invention is characterized by what is presented in claims 1 and 75.
  • the system for manufacturing a composite product is characterized by what is presented in claim 73.
  • the composite product comprises matrix material, and fiber material comprising a first fiber fraction and a second fiber fraction, and - the first fiber fraction and the second fiber fraction differ from each other chemically or dimensionally, and
  • the length weighted average length of the first fiber fraction is less than 0.9 times the length weighted average length of the second fiber fraction.
  • the first fiber fraction comprises organic natural fiber based material.
  • the stiffness of the composite product times the impact properties of the composite product is at least 25 000 MN * kJ/m 4 .
  • the width of the fibers in the first fiber fraction is between 1 .5 and 4 times the thickness of the fibers in the first fiber fraction.
  • the width of the fibers in the second fiber fraction is between 1 .0 and 1 .3 times the thickness of the fibers in the second fiber fraction.
  • the width of the fibers in the second fiber fraction is between 5 and 60 ⁇ .
  • the thickness of the fibers in the second fiber fraction is between 5 and 60 ⁇ .
  • the width of the fibers in the first fiber fraction is between 15 and 50 ⁇ .
  • the thickness of the fibers in the first fiber fraction is between 5 and 18 ⁇ .
  • the first fiber fraction has a length weighted average fiber length of between 0.1 and 1 .3 mm.
  • the first fiber fraction has a length weighted average fiber length of between 0.2 and 2.8 mm.
  • the second fiber fraction comprises polymer fibers.
  • the second fiber fraction comprises glass fibers.
  • the second fiber fraction comprises carbon fibers.
  • the second fiber fraction comprises viscose fibers.
  • the composite product is a granulate or a pellet. In an embodiment, the composite product is a plate.
  • the composite product is a product of electronics industry.
  • the composite product is a product of an instrument, or a part of an instrument
  • the composite product is a product of a part of audiovisual (AV) equipment.
  • the product comprises between 1 and 20 wt. % of glass fibers, calculated from the total content of the composite product.
  • the product comprises between 1 and 20 wt. % of plastic fibers, calculated from the total content of the composite product.
  • the composite product that is dry absorbs moisture less than 1 .5 % of the weight of the composite product in the time of 48 hours (65 % RH and 27 Q C atmosphere). In an embodiment, the density of the composite product is between 0.90 and 1 .8 g/cm 3 .
  • the pore volume of the composite product is under 10 %. In an embodiment, the charpy notched impact of the composite product is at least 8 kJ/m 2 .
  • the second fiber fraction has a length weighted average fiber length between 1 .5 and 25 mm. In an embodiment, between 20 and 99 wt. % calculated from the total amount of fiber materials in the composite product, is included in the first fiber fraction.
  • the length weighted average length of the first fiber fraction is less than 0.7 times the length weighted average length of the second fiber fraction.
  • the first fiber fraction comprises chemical pulp. In an embodiment, the second fiber fraction comprises chemical pulp.
  • the chemical pulp consists of kraft pulp.
  • the lignin content of the first fiber fraction and/or the second fiber fraction is lower than 5 wt.%.
  • the first fiber fraction comprises at least 50 wt. % of virgin fibers. In an embodiment, the first fiber fraction comprises wood based material.
  • the wood based material comprises softwood.
  • the first fiber fraction comprises organic natural fiber based non-wood material.
  • the second fiber fraction comprises organic natural fiber based non-wood material.
  • the non-wood based material comprises straw, coconut, leaves, bark, seeds, hulls, flowers, vegetables or fruits from cotton, corn, wheat, oat, rye, barley, rice, flax, hemp, manila hemp, sisal hemp, jute, ramie, kenaf, bagasse, bamboo, or reed.
  • the first fiber fraction comprises fibers in a flake form having a width that is at least 2 times larger than the thickness of the fibers.
  • the matrix material is thermoplastic.
  • the matrix material comprises polyolefin.
  • the melting point of the matrix material is below 260 Q C.
  • the fiber length of at least 60 wt. % of the organic natural fiber based material in the composite product is between 0.1 mm and 1 .5 mm.
  • the length of at least 80 wt. % of the organic natural fiber based material is between 0.1 mm and 1 .5 mm, more preferably between 0.3 mm and 0.7 mm
  • the content of the organic natural fiber based material is between 20 and 80 dry wt. % calculated from the total dry weight of the composite product. In an embodiment, the content of the matrix material is between 20 and 80 dry wt. % calculated from the total dry weight of the composite product.
  • lignin content of the organic natural fiber based material is below 1 wt. %.
  • the content of flake-form fiber material in the composite product is at least 30 dry wt. % calculated from the total content of the organic natural fiber based material. In an embodiment, at least 90 wt. % of the organic natural fiber based material is wood based material.
  • the organic natural fiber based material comprises at least 80 wt. % of fiber materials having a length between 0.1 and 1 .0 mm.
  • the second fiber fraction comprises man-made fiber material.
  • the man-made fiber material comprises mineral fibers, metal fibers, and/or man-made polymer fibers.
  • the melting point of the man-made fiber material is at least 20 Q C higher than the melting point of the matrix material.
  • the man-made fiber material comprises hollow-core fibers.
  • the man-made fiber material comprises solid-core fibers.
  • the content of the man-made fiber material in the composite product is between 0.1 and 45 wt.%, more preferably between 1 and 20 dry wt. % calculated from the total dry weight of the composite product.
  • the composite product comprises more than one kind of man-made fiber material, and the length weighted average length of the organic natural fiber based material is less than 0.8 times the length weighted average length of the all man-made fiber materials.
  • the length weighted average length of the organic natural fiber based material is less than 0.5 times the length weighted average length of the man-made fiber materials.
  • the length of at least 80 wt. % of the man-made fiber material is between 1 .5 mm and 10 mm.
  • the length weighted average length of the man-made fiber material is between 2 mm and 5 mm.
  • a method for manufacturing a composite product comprising matrix material and fiber material comprising a first fiber fraction and a second fiber fraction, wherein the first fiber fraction preferably comprises organic natural fiber based material, the first fiber fraction and the second fiber fraction differ from each other chemically or dimensionally, and the length weighted average length of the first fiber fraction is less than 0.9 times the length weighted average length of the second fiber fraction, comprises
  • the moisture content of the mixture 15 before the composite product is formed is less than 7%
  • the second fiber fraction comprises solid-core fibers comprising two material layers, of which at least one comprises man-made fiber material.
  • the fiber material and the matrix material are added to the system in the form of granulates and/or pellets.
  • first fiber fraction and the second fiber fraction are added to the system in the same granulates. In an embodiment, the first fiber fraction and the second fiber fraction are added to the system in separate granulates.
  • the matrix material is thermoplastic.
  • the composite product is formed by injection moulding and/or extrusion.
  • the composite product is formed using an extruder in which the diameter of the extruder screw in the feeding area is between 30 mm and 550 mm. In an embodiment, the temperature at which the mixture 15 is formed is lower than 220 °C.
  • the moisture content of the organic natural fiber based material is below 7 %, preferably below 5 during the mixing.
  • At least one mixer that is capable of heating the mixture is used in the mixing.
  • a system for manufacturing a composite product comprising matrix material, and fiber material comprising a first fiber fraction and a second fiber fraction, wherein the first fiber fraction preferably comprises organic natural fiber based material, the first fiber fraction and the second fiber fraction differ from each other chemically or dimensionally, and the length weighted average length of the first fiber fraction is less than 0.9 times the length weighted average length of the second fiber fraction,
  • a first mixer for forming a mixture comprising said materials, means for forming a composite product comprising the mixture.
  • the first mixer and/or the means for forming the composite product comprises an extruder.
  • FIGS 1 to 3 show reduced flow chart illustrations of embodiments of the present invention.
  • Figure 4a shows an example of a composite product
  • Figure 4b shows an example of a final composite product
  • Figure 5 shows an example where the amounts of short and long fibers in the fiber materials are illustrated
  • Figures 6a to 6c show some example fibers.
  • fiber length means "the length weighted average length of fibers" or "the length of a single fiber”.
  • the thickness is a smaller dimension than the width or is equal to the width
  • the width is a smaller dimension than the length or is equal to the length
  • the dimensions of fibers refer to the dimensions of a separate fiber, not to flocks or similar structures.
  • the mechanical properties of composite products depend on many aspects. For example, if the product comprises fiber materials and polymers, the fiber type, the fiber properties, the fiber content, the fiber length, the dispersion, and the adhesion between the fibers and the matrix material, and the mechanical properties of matrix material have an effect on the mechanical properties of the product.
  • the stiffness of the composite product may increase if fiber materials are added to the matrix material. For example, wood and wood based cellulose fibers are typically quite short, but they may still increase the stiffness and the strength quite a lot.
  • the length of the fibers may be critical, for example, for the impact strength. Long fibres may maintain or even improve the impact strength and increase the stiffness and strength at the same time.
  • the fibers used in the composite product are very long.
  • the fiber length may decrease during the manufacturing stages of the composite product; thus, the fiber length of the fibers is often smaller in the composite product than in the raw materials.
  • short fibers are also preferably used in the composite product because, among other things, the long fibers increase the friction during extrusion and injection moulding processes and a higher injection pressure is needed to fill the mould.
  • the strength properties of the composite product may be increased if the product comprises both short and long fibers, but good processability may still be ensured.
  • a composite product comprising fibres with a bimodal fibre length distribution is produced.
  • the short fibres may enable a high fibre content, easier processing, improved stiffness and strength.
  • the longer fibres may further improve the strength and the stiffness and enable higher impact and melt strength.
  • L(average) ⁇ n * Lj 2 / ⁇ nj * Lj
  • rij refers to the number of fibers having the same length
  • Li refers to the length of fibers.
  • fiber material preferably comprises first fiber fraction and second fiber fraction.
  • the first fiber fraction comprises or consists of organic natural fiber based material.
  • the first fiber fraction comprises or consists of man-made fiber material.
  • the second fiber fraction comprises or consists of man- made fiber material.
  • the second fiber fraction comprises or consists of organic natural fiber based material.
  • organic natural fiber based material 1 1 refers to particles that contain cellulose.
  • the organic natural fiber based material can originate from any plant material that contains cellulose; i.e. both wood material and non-wood material can be used.
  • the wood material i.e. wood based material
  • wood based material can be softwood trees, such as spruce, pine, fir, larch, douglas-fir or hemlock, or hardwood trees, such as birch, aspen, poplar, alder, eucalyptus, or acacia, or a mixture of softwoods and hardwoods.
  • Non-wood material can be agricultural residues, grasses or other plant substances such as straw, coconut, leaves, bark, seeds, hulls, flowers, vegetables or fruits from cotton, corn, wheat, oat, rye, barley, rice, flax, hemp, manila hemp, sisal hemp, jute, ramie, kenaf, bagasse, bamboo, or reed.
  • At least 30 wt.% or at least 40 wt.%, more preferably at least 50 wt.% or at least 60 wt. %, and most preferably at least 80 wt. % or at least 90 wt.% of the organic natural fiber based material in the composite product and/or in the first fiber fraction and/or in the second fiber fraction is wood based.
  • % or at least 90 wt.% of the organic natural fiber based material in the composite product and/or in the first fiber fraction and/or in the second fiber fraction comes from hardwood.
  • at least 30 wt.% or at least 40 wt.%, more preferably at least 50 wt.% or at least 60 wt. %, and most preferably at least 80 wt. % or at least 90 wt.% of the hardwood is birch and/or eucalyptus.
  • the organic natural fiber based material in the composite product and/or in the first fiber fraction and/or in the second fiber fraction comes from softwood.
  • the total amount of the softwood and the hardwood in the organic natural fiber based material is not more than 100 wt. %.
  • at least 30 wt.% or at least 40 wt.%, more preferably at least 50 wt.% or at least 60 wt. %, and most preferably at least 80 wt. % or at least 90 wt.% of the softwood is pine or spruce.
  • the organic natural fiber based material can be in the form of fibers, such as floccules, single fibers, or parts of single fibers, or the organic natural fiber based material can be in the form of fiber-like particles, such as saw dust or ground material, where the material does not have an exactly spherical form, but the longest dimension of a particle is preferably less than 5 times longer than the smallest dimension.
  • the organic natural fiber based material is, at least partly, in the form of fibers.
  • at least 40 wt. % or at least 50 wt. %, more preferably at least 60 wt. % or at least 70 wt. % and most preferably at least 80 wt. % of the organic natural fiber based materials are in the form of fibers.
  • the organic natural fiber based material having a length of at least 0.1 mm, more preferably at least 0.2 mm and most preferably at least 0.3 mm are called fibers, and smaller particles than those mentioned above are called powder or fiber-like particles.
  • At least 70%, at least 80 % or at least 90 % of the organic natural fiber based material in the composite product and/or in the first fiber fraction and/or in the second fiber fraction has a length weighted fiber length smaller than 4 mm, smaller than 3 mm or smaller than 2.5 mm, more preferably smaller than 2.0 mm, smaller than 1 .5 mm, smaller than 1 .0 mm or smaller than 0.5 mm.
  • At least 70 %, at least 80 %, or at least 90 % of the organic natural fiber based material in the composite product and/or in the first fiber fraction and/or in the second fiber fraction has a length weighted fiber length of at least 0.1 mm or at least 0.2 mm, more preferably at least 0.3 mm or at least 0.4 mm.
  • the fiber in the composite product and/or in the first fiber fraction and/or in the second fiber fraction has a shape ratio relating to the ratio of the fiber length to the fiber thickness being at least 5, preferably at least 10, more preferably at least 25 and most preferably at least 40.
  • the fiber in the composite product and/or in the first fiber fraction and/or in the second fiber fraction has a shape ratio relating to the ratio of the fiber length to the fiber thickness being preferably 1500 at the most, more preferably 1000 at the most, and most preferably 500 at the most.
  • the fiber length of the organic natural fiber based material is measured using a so-called Fiberlab measuring device, manufactured by Metso.
  • the organic natural fiber based material 1 1 in the composite product and/or in the first fiber fraction and/or in the second fiber fraction comprises fibers in a flake form.
  • Flakes are fibers having a width that is at least 2 times greater than the thickness of the fibers.
  • the width of the flake is at least 2, preferably at least 2.5, and more preferable at least 3 times the thickness of the flake.
  • the flakes have a thickness between 1 micron and 30 micrometers, and more preferably the thickness of the flakes varies from 2 microns to 20 micrometers. Most preferably, the thickness of the flakes is smaller than 15 ⁇ , more preferably smaller than 10 ⁇ and most preferably smaller than 7 ⁇ .
  • the width of the flake is smaller than 500 ⁇ , preferably smaller than 200 ⁇ , and more preferably smaller than 50 ⁇ .
  • the aspect ratio relating to the ratio of the length to the width is between 10 and 100.
  • the aspect ratio relating to the ratio of the length to the thickness is lower than 1500 or lower than 1000, more preferably lower than 500 and most preferably between 25 and 300.
  • the length of the flake is at least 10 times the width of the flake.
  • the flake has a tabular shape.
  • the flake has a platy shape.
  • the organic natural fiber based material contains flake-form fiber material at least 30 dry wt. %, preferably at least 50 dry wt. % and more preferably at least 70 dry wt. % of the total amount of the organic natural fiber based material.
  • the organic natural fiber based material may comprise mechanically treated and/or chemically treated fibers and/or fiber-like particles.
  • the mechanically treated organic natural fiber based material may comprise, among other things, wood flour, saw dust, chip material, and/or mechanical pulp such as TMP (thermo mechanical pulp), GW (groundwood pulp) / SGW (stone groundwood pulp), PGW (pressure groundwood pulp), RMP (refiner mechanical pulp), and/or CTMP (chemithermomechanical pulp).
  • the mechanically treated organic natural fiber based material preferably comprises or consists of wood particles, such as wood fibers, but it may also comprise or consist of non-wood material.
  • the mechanically treated organic natural fiber based material may comprise recycled and/or virgin particles, such as fibers or fiber-like particles.
  • wood plastic composites comprise saw dust or at least other mechanically treated wood or plant particles as the main organic natural fiber based material.
  • the chemically treated organic natural fiber based material in the composite product and/or in the first fiber fraction and/or in the second fiber fraction preferably comprises or consists of chemical pulp.
  • the chemical pulp may come, for example, from a kraft process or a sulphite process, but also other chemical processes may be used, such as a soda pulping process.
  • the chemical pulp comes from the kraft process, also called as sulphate cooking process, which uses a mixture of sodium hydroxide (NaOH) and sodium sulphide (Na 2 S).
  • the chemically treated organic natural fiber based material in the composite product and/or in the first fiber fraction and/or in the second fiber fraction preferably comprises or consists of wood based cellulose, but it may also be non-wood material.
  • the chemically treated organic natural fiber based material may comprise recycled and/or virgin fibers and/or fiber-like particles.
  • at least 30 wt. % or at least 40 wt. %, more preferably at least 50 wt. % or at least 60 wt. %, and most preferably at least 80 wt. % or at least 90 wt. % of the organic natural fiber based material used in the composite product and/or in the first fiber fraction and/or in the second fiber fraction is chemically treated particles.
  • the lignin content of the chemically treated pulp is lower than 15 wt.%, preferably lower than 10 wt. % or lower than 5 wt.%, more preferably lower than 3 wt. %, lower than 2 wt. % or lower than 1 wt.% and most preferably lower than 0.5 wt.%.
  • the alfa cellulose content of the chemically treated pulp is above 50 wt.%, preferably above 60 wt.%, more preferably above 70 wt.% and most preferably above 72 wt.
  • the alfa cellulose content of the chemically treated pulp is below 99 wt.%, preferable below 90 wt.%, more preferably below 85 wt.% and most preferably below 80 wt.%.
  • at least 30 wt. % or at least 40 wt. %, more preferably at least 50 wt. % or at least 60 wt. %, and most preferably at least 80 wt. % or at least 90 wt. % of the organic natural fiber based material in the composite product and/or in the first fiber fraction and/or in the second fiber fraction are virgin.
  • lignin content of the organic natural fiber based material in the composite product and/or in the first fiber fraction and/or in the second fiber fraction is lower than 15 wt.%, preferably lower than 10 wt. % or lower than 5 wt.%, more preferably lower than 3 wt. % or lower than 1 wt.% and most preferably lower than 0.5 wt.%.
  • the lignin content may be low due to delignification process, or the lignin content of the organic natural fiber based material may be naturally on a low level.
  • the lignin content of the organic natural fiber based material is at least 0.05 wt. %, more preferably at least 0.10 wt.
  • the lignin content of the organic natural material is higher than 3 wt. %, higher than 5 wt. % or higher than 10 wt. %.
  • the organic natural fiber based starting material is in the form of a paper sheet or web, a board sheet or web, a pulp sheet or web, or compacted fiber matrix or pieces of compacted fibers and their combinations.
  • the organic natural fiber based starting material is treated, for example refined, to obtain the organic natural fiber based material used in this invention.
  • At least part of the organic natural fiber based starting material is in the form of large fibers or fiber bundles, paper chaff, pulp chaff, crushed pulp material, derivates thereof and their combinations.
  • the content of the organic natural fiber based material is calculated as the total content of the untreated and/or in the above-mentioned way mechanically treated, and/or in the above-mentioned way chemically treated organic natural fiber based material in the system or the product, and it does not comprise man-made fibers, such as viscose fibers.
  • the man-made fiber material may comprise, for example, mineral fibers and/or metal fibers, such as
  • man-made fiber material may comprise, for example, man-made polymer fibers, such as
  • Aramid e.g. Kevlar
  • LCP-fiber e.g. Vectran
  • the man-made fiber may be straight or it may be crimped, i.e. have angles.
  • the man-made fiber material may comprise or consist of synthetic plastic material(s).
  • the man-made fiber material comprises viscose fibers, polymer fibers, glass fibers, other inorganic fibers and/or carbon fibers.
  • at least 50 wt. % or at least 60 wt. %, more preferably at least 75 wt. % or at least 85 wt. %, and most preferably at least 90 wt. %, at least 95 wt. % or at least 98 wt. % of the man-made fiber material is viscose fibers, polymer fibers, glass fibers, other inorganic fibers and/or carbon fibers.
  • the man-made fiber material comprises glass fibers and/or polymer fibers. Therefore, advantageously at least 50 wt.
  • the melting point of man-made fiber material is at least 180 Q C, more preferably at least 210 Q C, or at least 240 Q C and most preferably at least 270 Q C or at least 300 Q C.
  • the glass transition temperature of the man-made fiber material is at least 180 Q C, more preferably at least 210 Q C, or at least 240 Q C and most preferably at least 270 Q C or at least 300 Q C.
  • the melting point and/or the glass transition temperature of all the components of the man-made fiber material and/or the second fiber fraction is at least 20 Q C, or at least 30 Q C higher, more preferably at least 40 Q C or at least 50 Q C higher, and most preferably at least 60 Q C or at least 70 Q C higher than said property of the matrix material, especially in the case of the man-made polymer fibers.
  • the product comprises the man- made polymer fibers, they are in the form of fibers not only during the manufacturing process but also in the manufactured composite product.
  • the man-made fiber comprises fibers having at least two different kinds of raw material layers.
  • the man-made fiber preferably comprises at least one inner material and at least one outer material.
  • the inner material is preferably made of man-made fiber material, and the outer material may comprise the man-made fiber material and/or the matrix material.
  • this kind of man-made fiber material comprises inner material consisting of PET, and outer material consisting of the matrix material.
  • the man-made fiber is a hollow-core fiber.
  • the man-made fiber preferably comprises outer material comprising or consisting of man-made fiber material.
  • the man-made fiber material comprises a solid-core fibers comprising, for example, one or two material layer(s).
  • the "matrix material 12" is preferably material which can be formed several times into a new shape when it is heated. This material keeps its new shape after cooling and it then flows very slowly, or it does not flow at all.
  • the matrix material has at least one repeat unit, and the molecular weight of the matrix material is higher than 18 g/mol, preferably higher than 100 g/mol, higher than 500 g/mol, or higher than 1000 g/mol, more preferably higher than 10 000 g/mol or higher than 100 000 g/mol.
  • the matrix material 12 preferably comprises thermoplastic material; hence, the matrix material includes thermoplastic components.
  • the amount of the thermoplastic material in the matrix material is at least 80 wt. %, more preferably at least 90 wt.
  • the matrix material comprises at least one crystalline polymer and/or at least one non-crystalline polymer, and/or at least one crystalline oligomer and/or at least one non-crystalline oligomer.
  • the matrix material comprises, in addition to the thermoplastic polymers, polymeric coupling agent(s).
  • the polymeric coupling agent preferably contains a moiety or moieties which are reactive or at least compatible with the matrix material, and a moiety or moieties which are reactive or at least compatible with the organic natural fiber based material. If the matrix material is non-polar, the moiety or moieties which are reactive or compatible with the matrix material are preferably non-polar.
  • the polymeric coupling agent contains the same repeat units as the matrix material used.
  • at least 30 wt. % or at least 40 wt. %, more preferably at least 50 wt. % or at least 60 wt. %, and most preferably at least 80 wt. % or at least 85 wt. % of the moieties of the polymeric coupling agent are chemically the same as in the matrix material.
  • said moiety or moieties which is/are reactive or at least compatible with the organic natural fiber based material comprise(s) anhydride(s), acid(s), alcohol(s), isocyanate(s), and/or aldehyde(s).
  • the coupling agent is an acrylic acid grafted polymer.
  • the coupling agent is a methacrylic acid grafted polymer.
  • the coupling agent comprises or consists of a maleinic acid anhydride grafted polymer.
  • the coupling agent can, in principle, be any chemical which is capable of improving the adhesion between the two main components. This means that it may contain components which are known to be reactive or compatible with matrix material and components, which are known to be reactive or compatible with the organic natural fiber based material.
  • anhydrides preferably maleic anhydride (MA)
  • MAPP Maleated polypropylene
  • SEBS-MA Styrene-ethylene-butylene-styrene/maleic anhydride
  • SMA Styrene/maleic anhydride
  • organic-inorganic agents preferably silanes and/or alkoxysilanes.
  • at least 50 wt. %, at least 60 wt. %, more preferably at least 70 wt. % or at least 80 wt. % and most preferably at least 90 wt. % of the coupling agents used are preferably silanes and/or alkoxysilanes.
  • at least 50 wt. %, at least 60 wt. %, more preferably at least 70 wt. % or at least 80 wt. % and most preferably at least 90 wt. % of the coupling agents used are
  • anhydrides preferably maleic anhydride (MA)
  • MA maleic anhydride
  • copolymers preferably maleated polyethylene
  • MAPP Maleated polypropylene
  • SEBS-MA Styrene-ethylene-butylene-styrene/maleic anhydride
  • SMA Styrene/maleic anhydride
  • Organic-inorganic agents preferably silanes and/or alkoxysilanes.
  • the matrix material 12 comprises thermoplastic polymer based matrix material and/or thermoplastic oligomer based matrix material.
  • Thermoplastic polymers are often solid at a low temperature and they form a viscose polymer melt at elevated temperatures. Typically, the viscosity of these polymer decreases when temperature is increased, and the polymers flow and wet the surfaces more easily.
  • thermoplastic composites are produced, the polymer is heated in order to melt the polymer, and other components of the composites are mixed with the polymer melt. It is often easy to mix these other components with the polymer when the viscosity of the polymer is low, which means that the temperature of the polymer melt is high.
  • the matrix material is, at least partly, in molten form wherein
  • the organic natural material can adhere to the matrix material, and/or
  • melt flow index of the material can be measured (according to standard ISO 1 133 (valid in 201 1 )), and/or
  • the organic natural fibre material can adhere to the surfaces of matrix material particles.
  • the polymer based matrix material contains one or more polymers, and the oligomer based matrix material contains one or more oligomers.
  • the total content of the polymers and oligomers calculated from the total amount of the matrix material is preferably at least 80 wt. %, at least 85 wt. %, at least 90 wt. %, at least 95 wt. % or at least 98 wt. %.
  • the matrix material comprises polymer, it may be any suitable polymer or polymer composition.
  • the matrix material contains at least 50 wt.%, at least 60 wt.%, more preferably at least 70 wt. %, or at least 80 wt.%, and most preferably at least 90 wt.% or at least 95 wt.% of:
  • polyolefin e.g. polyethylene and polypropylene including copolymers
  • ABS acrylic nitrile butadiene styrene copolymer
  • biopolymer e.g. polylactide
  • the matrix material 12 may contain one or more polymer material components.
  • at least one polymer is selected from the group consisting of polyethylene, polypropylene and their combinations.
  • the content of polypropylene and polyethylene in the matrix material is at least 50 wt.%, at least 60 wt.%, at least 70 wt. %, at least 80 wt.%, at least 90 wt.% or at least 95 wt.%.
  • the matrix material may be homo polymer, copolymer and/or random copolymer.
  • the melting point of the matrix material is below 260 Q C, below 240 Q C, or below 220 Q C, more preferably below 200 Q C, or below 180 Q C, and most preferably below 150 Q C.
  • the glass transition temperature of the matrix material is below 260 Q C, below 240 Q C, or below 220 Q C, more preferably below 200 Q C, or below 180 Q C, and most preferably below 150 °-C.
  • melt flow rate, MFR, of the matrix material is below 1000 g/10 min (230 Q C, 2.16 kg defined by ISO 1 133, valid 201 1 ), more preferably 0.1 - 200 g/10 min, most preferably 0.3 - 150 g/10 min.
  • the melt flow rate, MFR, of the matrix material is higher than 0.1 g/10 min (230 Q C, 2.16 kg defined by ISO 1 133, valid 201 1 ), more preferably higher than 1 g/10 min, most preferably higher than 3 g/10 min.
  • first fiber fraction 1 1 refers to a material fraction consisting of fiber material.
  • the fiber length of a fiber included in the first fiber fraction is at least 0.1 mm, more preferably at least 0.2 mm, and most preferably at least 0.3 mm, and preferably shorter than 1 .5 mm, more preferably shorter than 1 .2 mm and most preferably shorter than 1 .0 mm.
  • the width of fibers in the first fiber fraction is between 15 and 50 ⁇ , more preferably between 20 and 40 ⁇ , and most preferably between 22 and 35 ⁇ .
  • the thickness of fibers in the first fiber fraction is between 5 and 18 ⁇ , more preferably between 8 and 15 ⁇ .
  • the width of fibers in the first fiber fraction is between 1 .5 and 4 times, more preferably between 2 and 3 times the thickness of the fibers in the first fiber fraction.
  • the first fiber fraction comprises at least 50 wt. % or at least 60 wt. %, more preferably at least 70 wt. %, or at least 80 wt. %, and most preferably at least 90 wt. % or at least 95 wt. %, or exactly 100 wt. % of organic natural fiber based material.
  • the first fiber fraction may comprise man-made fiber material.
  • the first fiber fraction preferably comprises at least 20 wt. % or at least 40 wt. %, more preferably at least 60 wt. %, or at least 80 wt. %, and most preferably at least 90 wt. % or at least 95 wt. %, or exactly 100 wt. % of man-made fiber material.
  • the fiber material preferably the organic natural fiber based material, having a fiber length of at least 0.1 mm, more preferably at least 0.2 mm, and most preferably at least 0.3 mm, and preferably shorter than 1 .5 mm, more preferably shorter than 1 .2 mm and most preferably shorter than 1 .0 mm is included in the first fiber fraction.
  • the first fiber fraction has a length weighted average fiber length of between 0.1 and 1 .3 mm, or between 0.15 and 1 .0 mm, more preferably between 0.2 and 0.8 mm, and most preferably between 0.3 and 0.7 mm. In an embodiment, at least 80 wt. %, more preferably at least 90 wt. % and most preferably at least 95 wt. %, or exactly 100 wt.
  • % of the fibers in the first fiber fraction have a fiber length of at least 0.1 mm, more preferably at least 0.2 mm and most preferably at least 0.3 mm, and preferably shorter than 1 .5 mm, more preferably less than 1 .2 mm, and most preferably shorter than 1 .0 mm.
  • the first fiber fraction has a length weighted average fiber length of between 0.2 and 2.8 mm, or between 0.5 and 2.5 mm, more preferably between 0.8 and 2.2 mm, and most preferably between 1 .2 and 1 .8 mm. In this embodiment, preferably at least 80 wt. %, more preferably at least 90 wt. % and most preferably at least 95 wt. %, or exactly 100 wt.
  • % of the fibers in the first fiber fraction have a fiber length of at least 0.1 mm, more preferably at least 0.2 mm and most preferably at least 0.3 mm, and preferably shorter than 2.8 mm, more preferably shorter than 2.2 mm, and most preferably shorter than 1 .8 mm.
  • the term "second fiber fraction 13" refers to a fraction consisting of fiber material.
  • the fiber length of a fiber included in the second fiber fraction is at least 1 .5 mm, more preferably at least 2.0 mm and most preferably at least 2.5 mm, and preferably shorter than 15 mm, more preferably shorter than 10 mm or less than 7 mm, and most preferably shorter than 5 mm.
  • the second fiber fraction preferably comprises or consists of man-made fibres.
  • at least 50 wt. % or at least 60 wt. %, more preferably at least 70 wt. %, or at least 80 wt. %, and most preferably at least 90 wt. % or at least 95 wt. %, or exactly 100 wt. % of the fibers in the second fiber fraction are man-made fibers.
  • the second fiber fraction may comprise organic natural fiber material.
  • at least 20 wt. % or at least 40 wt. %, more preferably at least 60 wt. %, or at least 80 wt. %, and most preferably at least 90 wt. % or at least 95 wt. %, or exactly 100 wt. % of the fibers in the second fiber fraction are organic natural fiber based material.
  • the width of fibers in the second fiber fraction is between 5 and 60 ⁇ , more preferably between 10 and 30 ⁇ .
  • the thickness of fibers in the second fiber fraction is between 5 and 60 ⁇ , more preferably between 10 and 30 ⁇ .
  • the width of fibers in the second fiber fraction is between 0.7 and 1 .3 times, more preferably between 0.8 and 1 .2 times, and most preferably between 0.9 and 1 .1 times the thickness of the fibers in the second fiber fraction.
  • the man-made fiber material having a fiber length of at least 1 .5 mm, or at least 2.0 mm, more preferably at least 2.3 mm, at least 2.5 mm, or at least 2.8 mm and most preferably at least 3 mm, or at least 4 mm, and preferably less than 15 mm, more preferably shorter than 10 mm or shorter than 7 mm, and most preferably shorter than 5 mm is included in the second fiber fraction.
  • the second fiber fraction has a length weighted average fiber length of between 1 .5 and 15 mm, more preferably between 2 and 10 mm, and most preferably between 2.5 and 5 mm.
  • at least 80 wt. %, more preferably at least 90 wt. % and most preferably at least 95 wt. %, or exactly 100 wt. % of the fibers in the second fiber fraction have a fiber length of at least 1 .5 mm, more preferably at least 2.0 mm and most preferably at least 2.5 mm, and preferably shorter than 15 mm, more preferably shorter than 10 mm or less than 7 mm, and most preferably shorter than 5 mm.
  • the length weighted average length of the first fiber fraction is less than 0.9 times, less than 0.8 times or less than 0.7 times, more preferably less than 0.5 times or less than 0.4 times, and most preferably less than 0.3 times, less than 0.2 times, or less than 0.1 times the length weighted average length of the second fiber fraction.
  • the length weighted average length of the second fiber fraction is 2.5 mm
  • the length weighted average length of the first fiber fraction is most preferably less than 0.5 mm.
  • the length weighted fiber length of the second fiber fraction is at least 0.1 mm greater or at least 0.2 mm greater, more preferably at least 0.4 mm greater, at least 0.6 mm greater, or at least 0.8 mm greater, and most preferably at least 1 .0 mm greater, at least 1 .1 mm greater, or at least 1 .2 mm greater than the length weighted fiber length of the first fiber fraction.
  • the length weighted average length of the second fiber fraction is at least 1 .25 times or at least 1 .5 times, more preferably at least 2 times, or at least 2.5 times, and most preferably at least 3 times, at least 4 times, or at least 5 times the length weighted average length of the first fiber fraction. For example, if the length weighted average length of the first fiber fraction is 0.5 mm, the length weighted average length of the second fiber fraction is most preferably at least 2.5 mm.
  • At least 50 wt. %, or at least 60 wt. %, more preferably at least 70 wt. % or at least 80 wt. %, and most preferably at least 85 wt. % or at least 90 wt. % of fibers of the fiber materials 1 1 , 13 have fiber length between 0.1 and 1 .3 mm or between 2 and 10 mm, more preferably between 0.2 and 1 .2 mm or between 2.5 and 7 mm, and most preferably between 0.3 and 1 .0 mm or between 3 and 5 mm.
  • the second fiber fraction comprises at least one kind of man- made fiber material.
  • the above mentioned numbers and ranges relating to the second fiber fraction are calculated using one, two, or three kinds of man-made fiber material. Most preferably, the above mentioned numbers and ranges are calculated from the total amount of the man-made fiber material(s).
  • the first fiber fraction may comprise man-made fiber material.
  • the first fiber fraction comprises organic natural fiber based material.
  • the first fiber fraction comprises or consists of wood based organic natural fiber based material
  • the second fiber fraction comprises or consists of non-wood based organic natural fiber based material, such as hemp.
  • the first fiber fraction may comprise or consist of wood based organic natural fiber based material
  • the second fiber fraction may comprise or consist of wood based organic natural fiber based material.
  • the first fiber fraction may comprise or consist of non- wood based organic natural fiber based material
  • the second fiber fraction may comprise or consist of wood based organic natural fiber based material
  • the first fiber fraction may comprise or consist of non-wood based organic natural fiber based material
  • the second fiber fraction may comprise or consist of non-wood based organic natural fiber based material
  • the fibers of the composite orientate during manufacturing processes. Often, the direction of the orientation is the same as the flow direction of the composite. In any case, the average orientation direction can be calculated for the composite by measuring the direction of individual fibers and calculating the average orientation.
  • the orientation may be calculated from a small cube which typically has dimensions smaller than 2 mm, more preferably smaller than 1 mm and most preferably smaller than 0.5 mm.
  • the orientation of fibers is typically not uniform, which means that the fibers have some average difference angle to the average orientation direction. The average difference angle depends on the fiber properties and the flow during the composite production. Because the orientation depends on the fiber properties, the first and second fiber fractions can have different average difference angles to the average orientation direction.
  • the orientation of the fibers of the second fiber fraction is at least 1 %, or at least 3%, more preferably at least 5% or at least 7%, and most preferably at least 10%, at least 15%, or at least 17% greater than the orientation of the fibers of the first fiber fraction. This may give the composite product better strength properties.
  • the second fiber fraction comprises or consists of organic natural fiber based material.
  • the organic natural fiber based material having a length shorter than 1 .5 mm is included in the first fiber fraction, and the organic natural fiber based material having a length at least 1 .5 mm is included in the second fiber fraction.
  • chemical(s) are used in order to improve adhesion and, hence, the properties of the composite product.
  • lubricant(s), waxe(s), compatibilization agent(s), ionic surfactant(s), non-ionic surfactant(s), silane(s), acid anhydride(s) and/or carboxylic acid(s) are used for the chemical pretreatment.
  • another chemical(s) which improves the wetting of fibers or adhesion between the organic natural fiber based material and the matrix material may be used, especially if the chemical is in liquid form or in gas form or in melt form below temperatures at which the matrix material is in solid form.
  • Suitable and desired additives can be added into the organic natural fiber based material, the matrix material and/or the mixture comprising the matrix material and the organic natural fiber based material.
  • at least one additive comprising
  • Halloysite e.g. Dragonite
  • At least one filler comprising fibrous material, organic fillers like starch or protein or some organic residues, inorganic fillers, powdery reinforcements, calcium carbonate and/or talc is used.
  • the total content of the fillers is preferably lower than 50 wt. % or lower than 40 wt. %, more preferably lower than 30 wt. % or lower than 20 wt. %, and most preferably lower than 10 wt. % calculated from the total weight of the composite product.
  • the coupling agent is a polymeric coupling agent which is included in the matrix material.
  • FIGS 1 to 6 show some example embodiments of the present invention.
  • FIGS 1 to 3 show reduced flow chart illustrations of embodiments of the present invention.
  • a mixture 15, 15b comprising fiber materials 1 1 , 13 and matrix material 12 are fed into the system.
  • An apparatus 39 is used to form the composite product 40, 40a, 40b comprising the mixture.
  • the first fiber fraction 1 1 , the second fiber fraction 13, and the matrix material 12 are mixed with each other to form a mixture 15.
  • the mixing may be implemented in an apparatus 30 or in a separate mixer. In the case of the separate mixer, the mixture is conveyed to the apparatus 39 in order to form the composite product 40.
  • an intermediate product 40a such as a plate, is treated in an apparatus 39b in order to form a final product 40b from the intermediate product 40a.
  • Figure 5 shows an example embodiment of the present invention, in which the amount of short fibers and long fibers are illustrated.
  • the first fiber fraction 1 1 comprises short fibers and the second fiber fraction comprises long fibers 13, and the amount of the short fibers is greater than the amount of the long fibers.
  • the system according to the present invention comprises at least an apparatus 39 for forming a composite product comprising the fiber materials 1 1 , 13 and the matrix material 12.
  • at least one mixer that is capable of heating the matrix material is used in the invention. Therefore, the system preferably comprises a mixer to form a mixture comprising the fiber material 1 1 , 13, and the matrix material 12.
  • the mixer preferably comprises a heating section.
  • the mixture 15 may be formed, for example, from granulates or pellets.
  • the mixer may be a part of the apparatus 39 for forming a composite product, or it may be a separate apparatus.
  • the composite product 40 and compounding of the materials are preferably formed with an extruder; hence, the apparatus 39 for forming the composite product 40, 40a, 40b is preferably an extruder.
  • Extruders can be divided into single, twin or multiple screw machines.
  • the single screw can be with a smooth, grooved or pin barrel machine.
  • the twin screw extruder can be a conical co-rotating twin screw extruder, a conical counter-rotating twin screw extruder, a parallel co-rotating twin screw extruder, or a parallel counter- rotating twin screw extruder.
  • the multiple screw extruders can be with a rotating or static center shaft.
  • any suitable single-screw extruder or twin-screw extruder such as a counter-rotating twin-screw extruder or a co-rotating twin- screw extruder, may be used.
  • the twin-screw extruder can have parallel or conical screw configuration.
  • the melt of the mixture 15 comprising the fiber materials and the matrix material is conveyed to a co-rotating parallel twin screw extruder.
  • the screw volume can be, for example, from 4 to 8 times larger at the beginning of the screw than at the end of the extruder.
  • the diameter of the extruder screw in the feeding area is advantageously at least 30 mm, at least 40 mm, or at least 50 mm, more preferably at least 60 mm or at least 70 mm, and the most preferably at least 90 mm or at least 1 10 mm.
  • the diameter of the extruder screw in the feeding area is preferably not larger than 550 mm or not larger than 500 mm, more preferably not larger than 450 mm or not larger than 400 mm, and most preferably not more than 350 mm or not more than 300 mm.
  • the free volume used is preferably at least 200 liters, at least 400 liters or at least 500 liters, more preferably at least 600 liters or at least 800 liters, and most preferably at least 1000 liters or at least 1500 liters.
  • the production capacity of the apparatus used for the manufacturing process is at least 300 kg/h or at least 400 kg/h, more preferably at least 500 kg/h or at least 700 kg/h, and most preferably at least 1000 kg/h or at least 1500 kg/h.
  • the raw materials 1 1 , 12, 13 of the composite product 40, 40a, 40b may be, for example, in separate particles, or in separate pellets or in separate granulates, i.e. the raw materials are not mixed with each other in any pre- treatment step, or the raw materials 1 1 , 12, 13 may be in the form of a mixture 15 comprising the raw materials 1 1 , 12, 13, or in the form of pellets or granulates 15b comprising the mixture 15.
  • the quantity and/or the content of the raw materials 1 1 , 12, 13 is selected according to the predetermined quantity of the raw materials in the final product.
  • the first fiber fraction is mixed together with the matrix material, and/or the second fiber fraction is mixed together with the matrix material in the raw materials.
  • the raw materials comprise the first fiber fraction, the second fiber fraction, and/or the matrix material, which are all in separate pellets and/or granulates.
  • the composite product 40 and/or compounding of the materials can be formed with mixers such as a batch type internal mixer, an internal mixer, a heating mixer, a heating-cooling mixer, or z-blade mixer, or with any mixing device where matrix material is melted with friction and/or internal and/or external heat and fibers are incorporated to the matrix material and other components.
  • the mixing can be a batch or continuous process.
  • the mixer preferably comprises a section in which at least some of the moisture coming from the raw materials can be removed.
  • the fiber materials 1 1 , 13 and the matrix material 12 can be mixed and agglomerated to form a homogeneous or substantially homogeneous mixture.
  • the fiber content may be adjustable within a wide range, and high contents may be easy to achieve.
  • the composite product 40 and compounding of the materials can be formed with any of these or a combination of these and some other process steps.
  • Any of the mixers or extruders might contain some pre or post processing directly included in the extruder or mixer or by connecting shortly before or after the extruder.
  • shredding, drying, and/or mixing are performed in a continuous process directly connected to extruder.
  • the method according to the present invention comprises at least some of the following steps:
  • the temperature in the above mentioned process stage, in which the mixture 15 is formed is lower than 220 °C, more preferably lower than 200 °C, and most preferably lower than 180 °C.
  • the composite product is manufactured by injection moulding, film casting, blow moulding, rotomoulding, thermoforming, compression moulding, re-extrusion, profile extrusion, sheet extrusion, film extrusion, coextrusion and/or fiber extrusion.
  • the composite product is formed by injection moulding, and/or extrusion, and/or pultrusion.
  • the organic natural fiber based material and/or the man- made fiber material is/are mixed with the matrix material and additives before adding the mixture, for example, into the extruder.
  • the composite product is a final product 40b.
  • the composite product is an intermediate product 40a, such as a plate that is used to form the final product.
  • the composite product 40 preferably the intermediate product 40a, is a granulate and/or a pellet.
  • the size of the granulate and/or the pellet is preferably between 5 and 25 mm, more preferably at least 6 mm or at least 8 mm, and most preferably between 10 and 20 mm.
  • the matrix material 12 is arranged at least partly in the form of melt at least in the step in which the composite product 40, 40a, 40b is formed.
  • the fiber materials 1 1 , 13 are mixed with the melted matrix material to form a mixture comprising at least said fiber materials and the matrix material.
  • Matrix material is often melted mainly with friction, but some external heat can be used.
  • the material of the second fiber fraction 13 does not melt in the manufacturing process.
  • the composite forming stage may be a part of a continuous process.
  • the invention may provide composite products with good mechanical properties.
  • Figure 4a shows a side projection of an example intermediate composite product.
  • the intermediate composite product is a plate.
  • Figure 4b shows an example of a final composite product.
  • the final composite product is a shoehorn.
  • Figure 4 shows several shoehorns with different shades/colors.
  • the composite product 40, 40a, 40b is formed from the mixture comprising the fiber materials, and the matrix material.
  • the moisture content of the mixture 15 before the composite product is formed is preferably less than 7%, less than 6%, less than 5%, less than 4%, or less than 3%, more preferably less than 2.5%, less than 2.0%, less than 1 .5% or less than 1 .0%, and most preferably less than 0.8%, less than 0.5%, less than 0.2%, or less than 0.1 %.
  • first fiber fraction 1 1 , the second fiber fraction 13, and the matrix material 12 are fed to the system separately. In another embodiment, the first fiber fraction 1 1 , the second fiber fraction 13, and the matrix material 12 are fed to the system together.
  • the fiber materials and the matrix material are added to the system in the form of granulates and/or pellets.
  • This kind of pre-granulation may be important when organic natural fiber based material is used.
  • the matrix material comprises matrix material, which is added to the process in the form of powder and/or fibers.
  • the first fiber fraction, the second fiber fraction, and/or the matrix material are fed to the system in separate granulates and/or pellets, and/or they may be fed to the system with each other in same granulates and/or a pellets.
  • the pellet and/or the granulate fed to the system comprises or consists of the first fiber fraction and the matrix material.
  • the pellet and/or the granulate comprises or consists of the second fiber fraction and the matrix material.
  • the pellet and/or the granulate comprises or consists of the second fiber fraction, the first fiber fraction, and the matrix material.
  • the granulates or pellets can be manufactured with different methods.
  • the composite particles are preferably formed by a granulation method, a pelleting method, an agglomeration method or their combinations.
  • the granulation is carried out by means of a method selected from the group consisting of water ring, underwater pelleting, air cooled, hot face strand, and their combinations.
  • the granulation is made under water.
  • the granulation is carried out by means of counterpressure, e.g. with an underwater method.
  • the simplest way to produce natural fiber-polymer granulates is to use one machine or one machine combination which compounds material components and forms this material to granulates.
  • a machine is a compounding twin screw extruder with a granulation tool.
  • the granulates are finish-treated. Finish-treatment for granulates comprises, for example, drying, dust removing, classification and/or packing.
  • the composite product 40 is in the form of a plate.
  • This kind of a composite product 40 is typically an intermediate composite product 40a which is formed into a final composite product 40b afterwards.
  • the composite product 40 is a final product 40b.
  • the final product may be manufactured from the intermediate composite product 40a by any suitable method, such as molding, extrusion, thermoforming, compression molding, vacuum forming, film casting, rotomolding, glueing, cutting and/or grinding.
  • the total content of the natural organic fiber material, the man- made fiber material, and the matrix material in the composite product is at least 30 wt. % or at least 50 wt. %, more preferably at least 60 wt. % or at least 70 wt. % and most preferably at least 80 wt. % or at least 90 wt. % calculated from the total dry weight of the composite product.
  • the total content of the natural organic fiber material in the composite product is between 20 and 99 wt. %, or between 30 and 98 wt. %, more preferably between 40 and 95 wt. %, or between 50 and 90 wt. %, or between 60 and 87 wt. %, and most preferably between 70 and 85 wt. %, or between 75 and 83 wt. % calculated from the total dry weight of the fiber materials in the composite product.
  • the content of the matrix material is between 5 and 95 wt. %, or between 10 and 90 wt. %, more preferably between 15 and 85 wt. %, or between 25 and 82 wt.
  • the matrix material is thermoplastic.
  • the melting point of the matrix material is under 250 Q C and/or the glass transition temperature of the matrix material is under 250 Q C.
  • the composite product according to the present invention comprises between 10 and 80 wt. % or between 12 and 70 wt. % more preferably between 14 and 65 wt. % or between 16 and 60 wt. %, and most preferably between 18 and 55 wt. % or between 20 and 50 wt. % of organic natural fiber based material.
  • the fiber length of at least 60 wt. %, more preferably at least 80 wt. %, and most preferably at least 90 wt. % of the organic natural fiber based material is between 0.1 mm and 1 .5 mm.
  • the content of the man-made fiber material is between 0.1 and 45 wt.% or between 1 and 35 wt. %, more preferably between 2 and 30 wt.%, or between 3 and 25 wt.%, and most preferably between 4 and 20 wt.% or 5 and 15 wt.% calculated from the total dry weight of the composite product.
  • melting point of the man-made fiber material is at least 200 Q C, more preferably at least 210 Q C, or at least 250 Q C. Most preferably, the melting point and/or the glass transition temperature of the man-made fiber material is at least 20 Q C greater than in the matrix material.
  • the composite product comprises between 1 and 20 wt. %, more preferably at least 2 wt. %, at least 3 wt. %, or at least 5 wt. %, and most preferably at least 7 wt. % or at least 10 wt.% glass fibers calculated from the total amount of materials in the composite product.
  • the composite product comprises between 1 and 20 wt. %, more preferably at least 2 wt. %, at least 3 wt. %, or at least 5 wt. %, and most preferably at least 7 wt. % or at least 10 wt.% of plastic fibers calculated from total amount of materials in the composite product.
  • the fiber length of at least 60 wt. %, more preferably at least 80 wt. %, and most preferably at least 90 wt. % of the man-made fiber material is between 1 .5 mm and 25 mm, between 2 and 20 mm, or between 3 and 15 mm.
  • the length weighted average length of the natural organic fiber material is between 0.05 and 0.99 times, or between 0.1 and 0.95 times, or between 0.2 and 0.90 times, more preferably between 0.3 and 0.85 times, or between 0.4 and 0.90 times the length weighted average length of the man-made fiber material and/or the second fiber fraction.
  • the composite product according to the present invention comprises additives and/or fillers, the total amount of said additives and fillers being between 0 and 50 wt. %, more preferably between 0.5 and 40 wt.% or between 1 and 30 wt.%, and most preferably between 3 and 25 wt.%, or between 5 and 20 wt.%.
  • the composite product that is dry absorbs moisture under 1 .5 % from the weight of the composite product in the time of 48 hours (65 % RH and 27 °-C atmosphere).
  • Advantageously charpy notched impact of the composite product is at least 8 kJ/m 2 , or at least 9 kJ/m 2 , more preferably at least 10 kJ/m 2 , at least 1 1 kJ/m 2 , or at least 12 kJ/m 2 , and most preferably at least 13 kJ/m 2 , at least 14 kJ/m 2 , or at least 15 kJ/m 2 .
  • the balance between stiffness and impact strength is controlled, for example, by the proper selection of matrix and/or fibers in the composite product.
  • the stiffness of the composite product tensile modulus, according to ISO 527-1 /2, 1 mm/min, valid 2012
  • impact properties of the composite product notched Charpy impact strength according to ISO 179-1 /1 eA, ISO 179-2/1 eA, valid 2012
  • stiffness of the composite product x impact properties of the composite product is high, which means that the material is stiff, but it is not very fragile at the same time. This may be a very important combination of the properties in many applications, because the mechanical calculations of the product are often based on the stiffness, and the stiffness of the product has to be sufficiently high. If the material is very stiff, thinner and lighter structures can be used.
  • the impact strength of the material can be a problem and that is why certain stiffness and impact strength values are wanted.
  • the stiffness times the impact properties of the composite material containing the first and second fiber fractions is between 7 000 MN * kJ/m 4 and 200 000 MN * kJ/m 4 , more preferably between 15 000 MN * kJ/m 4 and 195 000 MN * kJ/m 4 , or between 20 000 MN * kJ/m 4 and 192 000 MN * kJ/m 4 , and most preferably between 25 000 MN * kJ/m 4 and 190 000 MN * kJ/m 4 .
  • the stiffness times the impact properties of the composite containing the first and second fiber fractions is at least 6 000 MN * kJ/m 4 or at least 12 000 MN * kJ/m 4 , more preferably at least 25 000 MN * kJ/m 4 , at least 35 000 MN * kJ/m 4 , or at least 45 000 MN * kJ/m 4 , and most preferably at least 75 000 MN * kJ/m 4 or at least 100000 MN * kJ/m 4 .
  • the theoretical/calculatory density (p t ) of a composite material may be calculated from the masses and the densities of each individual component according to equation:
  • Pi P2 Pn where m-i , m 2 , and m n are the masses of each individual component of the composite material, e.g. the composite product or the mixture containing fiber materials and the matrix material, and pi , p 2 , p n are the densities of each individual component of the composite material, e.g. the composite product or the mixture containing fiber material and matrix material.
  • the density of the composite product is between 0.90 and 1 .8 g/cm 3 , or between 0.93 and 1 .6 g/cm 3 , more preferably between 0.95 and 1 .30 g/cm 3 , or between 0.97 and 1 .20 g/cm 3 , and most preferably between 1 .00 and 1 .15 g/cm 3 .
  • the density of the composite product is at least 85 %, preferably over 90 %, more preferably over 95 % and most preferably over 98 % of the theoretical density. In an embodiment, the density of the composite product is at most 99.9 % of the theoretical density.
  • porosity into the composite product reduces the density of said product. Ideally, there is no unwanted porosity in the composite product. In practice, some porosity may exist, no matter how good the process is in regard to minimizing the formation of porosity. Therefore, the density can be used as one quantity for characterization of an organic natural fiber - thermoplastic polymer composite product.
  • a composite product can be characterized by its theoretical/calculatory density and its experimental density.
  • the term "pore volume" refers to a sum of partial volumes formed of gas volumes inside the object compared with the total volume of the object. In one embodiment, the pore volume of the mixture and/or the composite product is lower than 10 %, preferably lower than 5 %, more preferably lower than 2 % and most preferably lower than 1 %.
  • the organic natural fiber based material has the character that it absorbs water.
  • the amount of water absorption depends on the condition around the material. Cellulose fibers absorb water quite rapidly, but when fibers are covered by hydrophobic matrix material, the absorption is much slower.
  • the absorption rate depends on the character of the matrix material, the organic natural material content, but other things like additives can increase or decrease the absorption rate.
  • a dry composite product 40, 40a, 40b absorbs moisture less than 1 .5 %, less than 1 .0 %, or less than 0.85 %, more preferably less than 0.7 %, less than 0.6 % or less than 0.5 %, and most preferably less than 0.4 %, less than 0.3 %, less than 0.2 % or less than 0.15 % of the weight of the composite product in the time of 48 hours (65 % RH and 27 Q C atmosphere).
  • the components for the composition may be selected to obtain a desired density and heat expansion for the composite material.
  • Heat expansion may depend of the direction in the composite structure.
  • the composition composite structure may have an effect on the heat expansion. For example, heat expansion in a composite structure comprising 40 w-% of organic natural fiber material may have a larger heat expansion than a composite structure comprising 50 w-% of organic natural fiber material. Therefore, the dimensional stability of a composite structure comprising 50 w-% of organic natural fiber material may be improved compared to a composite structure comprising less organic natural fiber material. The selection of the composition may therefore be used to control the speed of sound in the material.
  • the present invention provides an industrially applicable, simple and affordable way of making intermediate composite products 40a and final composite products 40b from the fiber materials and matrix material.
  • the method according to the present invention can be easy and simple to realize as a production process.
  • the method according to the present invention is suitable for use in the manufacture of different products from different organic natural fiber based materials.
  • the intermediate composite product is a plate, a granulate, or a pellet.
  • the sizes of the granulates are preferably in the same range.
  • the weight of one granulate is preferably between 0.01 and 0.10 g. More preferably, the weight of one granulate is between 0.015 and 0.05 g.
  • the weights of 100 granulates is preferably between 1 and 10 g, more preferably between 1 .5 and 5 g, and most preferably between 2.0 and 4.0 g.
  • the standard deviation in the weight of the granulate is preferably less than 15 %, more preferably less than 7 %, and most preferable less than 2 %.
  • the composite product 40 forms or is a part of
  • a bench for example a park bench
  • the composite product forms a product of electronics industry, or is a part of a product of electronics industry.
  • Figures 6a to 6c show some example fibers.
  • Figures 6a and 6b show a hollow fiber with four interfaces 51 , 52, 53, 54.
  • the fiber may be the organic natural fiber based material, or man-made fiber material.
  • Figure 6c shows a solid fiber with two interfaces 51 , 52.
  • the first fiber fraction may comprise or consist of the organic natural fiber based material having a structure, where the fiber has four interfaces, i.e. first interface 51 , second interface 52, third interface 53, and fourth interface 54, when the fiber is cut in a direction perpendicular to the longest dimension of the fiber and a line 50 is drawn across the fiber in a direction perpendicular to the first interface.
  • This kind of a structure may enable the fiber to have a large surface area, and it is possible to have good adhesion between the fibers and the matrix material.
  • the hollow-core fiber comprises a hollow in the middle of the fiber.
  • the thickness of all walls of the hollow- core fiber is substantially constant.
  • the distance between the first interface and the second interface is smaller than the distance between the first interface and the third interface.
  • the distance between the first interface and the third interface is smaller than the distance between the first interface and the fourth interface.
  • the distance between the first interface and the second interface is preferably less than 0.5 times the distance between the first interface and the fourth interfaces.
  • the distance between the first interface and the second interface is at most 0.4 times, more preferably at most 0.3 times the distance between the first interface and the fourth interface.
  • the distance between the first interface and the second interface is almost independent of the direction where the line is drawn, but the distance between the first interface and the fourth interface may depend heavily on the direction of the line.
  • the distance between the first interface and the second interface can be almost 0.5 times the distance between the first interface and the fourth interface.
  • the distance between the first interface and second interface can also be less than 0.2 times the distance between the first interface and the fourth interface. This leads to a situation where the fiber has an oval shape.
  • the distance between the first interface 51 and the second interface is preferably less than 60%, more preferably less than 50%, and most preferably less than 40% of the distance between the first interface 51 and the fourth interface 54.
  • the distance between the first interface 51 and the second interface 52 preferably differs less than 30% or less than 20%, more preferably less than 10%, and most preferably less than 5% of the distance between the third interface 53 and the fourth interface 54.
  • the distance between the first interface 51 and the fourth interface 54 may be, for example, from 2 to 12 times the distance between the first interface 51 and the second interface 52.
  • the second fiber fraction may comprise or consist of fiber material having a structure, where the fiber has only two interfaces 51 , 52, i.e. the first interface, and the second interface, when the fiber is cut in a direction perpendicular to the longest dimension of the fiber and a line is drawn across the fiber perpendicular to the first interface.
  • This kind of a structure leads to a smaller surface area.
  • the distance between the first interface and the second interface may be almost independent of the direction, which means that the cross section of the second fiber fraction is round.
  • Composite material containing organic natural fiber based material and man- made fiber material was prepared with a double-z-kneader as follows:
  • Example 2 Composite product containing organic natural fiber based material and man- made fiber material was formed by injection molding as follows:
  • Composite material containing organic natural fiber based material in pellet form, composite pellets containing man-made PET fibers of 12mm length, plastics and additives were mixed in a desired proportion before feeding into the throat of the injection molding machine and then molded into an item.
  • organic natural fiber based material containing composite pellets with 50% fiber content was mixed with 550g of composite pellets with a 20% content of man-made PET fibers of 12mm length and with 770g of virgin plastic pellets.
  • the mixture containing organic natural fiber based material, man-made fiber material, plastics and additives was injection molded into an item with a total fiber content of 40% and man-made fiber content of 2%, with improved impact, tensile, and flexural properties in the final product.
  • Organic natural fiber composite containing polypropylene and soft wood based kraft cellulose (fiber content of 40 wt.-%) was mixed with long glass fiber composite (fiber content of 40 wt.-%).
  • the long fiber composite contained polypropylene and the length of grass fibers was 10 mm before injection molding.
  • the length weighted length of cellulose fibers before injection molding was 1 .0 mm. Both fibers were in their own granulates and these granulates were mixed in different weight fractions in order to obtain a desired mixture of cellulose and glass fibers.
  • Granulate mixtures were injection moulded using melt temperatures below 200 °C. Mechanical properties are presented in the table 1 . Impact strength, modulus and tensile strength increased at the same time. It should be noted that the density increased at the same time from 1 ,07 g/cm 3 to 1 ,24 g/cm 3 .
  • Example 4 One important aspect of materials for engineering purposes and technical or structural applications is the balance between stiffness and impact strength. For example, soft rubber-like material may have excellent impact strength but its stiffness may be inadequate for engineering purposes. On the other hand, a material with high stiffness may be too brittle for an application that requires good impact toughness. Therefore, materials with balanced stiffness and impact properties are desired for many applications, and this can be done e.g. by a proper selection of matrix and fibers in composite materials. Table 2. shows stiffness (tensile modulus) and impact properties (notched Charpy impact strength) for certain plastics and composites.
  • Table 3 tensile modulus and Charpy notched impact strength and values for modulus multiplied by Charpy notched impact strength for different composite materials with different fiber content (columns 1 -4) are shown.
  • the table 3 shows, as an example, values for modulus multiplied by Charpy notched impact strength when the Charpy notched impact strength has given values (columns 5-9).
  • analysis methods can be used for determination of the organic natural fiber based material content and/or the man-made fiber material content of a composite.
  • Analysis methods suitable for determination of the organic natural fiber based material content and/or the man-made fiber material content of an unknown composite include, but are not limited to, physical, chemical, thermal, optical, and microscopy analysis techniques.
  • the organic natural fiber based material content and/or the man-made fiber material content of an unknown composite can be analyzed, for example, with thermogravimetric, calorimetric, spectroscopic, crystallographic, tomographic, and microscopic analysis, and by selectively degrading or dissolving the different components comprising the unknown composite in order to resolve the mass fraction of the organic natural fiber based material or the man-made fiber material.
  • the man-made fiber material content of a polyolefin based composite containing organic natural fiber based material and man-made fiber material can be determined by selectively dissolving the polyolefin matrix e.g. in decalin and/or xylene and then separating the organic natural fiber based material and man-made fiber material by selectively dissolving or degrading either fiber material depending on the type of man-made fiber material.
  • inorganic glass fibers as the man-made fiber material, can be separated by pyrolysis of the organic natural fiber based material after dissolving the polyolefin matrix, or by pyrolysis of the whole composite and by separating the inorganic glass fibers from the residue.
  • the organic natural fiber based material and man-made fiber material can be separated by dissolving the polyolefin matrix e.g. in decalin and/or xylene and then separating the organic natural fiber based material and man-made fiber material by selectively dissolving the organic natural fiber based material or the man-made fiber material, depending on the chemical structure of the organic polymer based man-made fiber material.
  • polyester based man-made fiber material can be dissolved in dichloromethane or methyl ethyl ketone where cellulose containing organic natural fiber based material is insoluble, thus providing means of separation of the organic natural fiber based material and man-made fiber material.
  • the separation between man-made fiber material and the organic natural fiber based material can be done by analysis of crystalline structure of the materials. For example, the alpha cellulose content of the man-made fiber material and the organic natural fiber based material together is measured and the proportions of man-made fiber material and the organic natural fiber based material in the sample is calculated depending on the origin of the organic natural fiber based material.
  • Another way of determining the content of organic natural fiber based material and man-made fiber material in a composite can be based on the quantification of the bio-based content according to standard ASTM-D6866 or with similar analysis methods that can differentiate between bio-based and non-bio-based chemical elements including, but not limited to, methods based on carbon dating.
  • the man-made fiber material is from non-renewable resources
  • a sample extracted from a composite material containing organic natural fiber based material and man- made fiber material is analyzed for bio-based content and the organic natural fiber content is calculated according to the molar fraction of the chemical element of interest in the organic natural fiber based material.
  • the final composite product contains polypropylene, hardwood cellulose and glass fibers.
  • the man-made fiber content can be measured by using pyrolysis. The temperature is selected so that more than 95 % of PP and cellulose fibers has been degraded. Test pyrolysis can be done to PP and cellulose fiber separately. The weight of the final composite product is measured before and after pyrolysis, and the man- made fiber content can be calculated from these results.
  • the organic natural fiber content of an unknown composite can be determined, for example, by x-ray diffraction and x-ray computed tomography techniques.
  • the organic natural fiber based material content of an unknown composite can be determined by different combinations of analysis methods including, but not limited to, the methods described above.
  • a sample of a composite material comprising organic natural fiber based material is analyzed with x-ray computed tomography and the content of the organic natural fiber based material within the sample is determined.
  • the fibers Due to the hygroscopic character of organic natural fibers, the fibers typically contain moisture.
  • the moisture content of the fibers depends, for example, on the origin of the fibers, on the storing conditions of the fibers, e.g. the relative humidity and the ambient temperature of the place where the fibers are stored, and on the processing of the fibers.
  • the presence of moisture cannot be fully excluded while processing organic natural fibers, and in some cases excess moisture can be harmful.
  • organic natural fiber and thermoplastic or other polymer composites the presence of moisture in processing can cause, for example, deterioration of product properties such as mechanical strength and visual appearance.
  • the processing temperatures of organic natural fiber- thermoplastic/polymer composites are typically above the boiling point of water due to the higher than 100°C melting and/or the glass transition temperatures of thermoplastic/polymers.
  • the vaporization of moisture contained in the fibers can cause formation of porosity in the product material.
  • the porosity can appear, for example, in the form of gas bubbles or voids between fiber surfaces and matrix polymer in the composite product.
  • Another reason for the formation of porosity can be inclusion of air or other ambient gases during the processing, due to insufficient gas removal in the process.
  • the feeding of reinforcement fibers brings a large volume of gases to be removed from the process.
  • sufficient venting is necessary in order to remove gaseous substances including water vapor, entrained air and other gases, and other volatile components.

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Abstract

This invention relates to a composite product comprising matrix material and fiber material. The fiber material comprises a first fiber fraction and a second fiber fraction. The first fiber fraction and the second fiber fraction differ from each other chemically or dimensionally, and the length weighted average length of the first fiber fraction is less than 0.9 times the length weighted average length of the second fiber fraction. The invention further relates to a system and a method for manufacturing a composite product.

Description

A METHOD AND A SYSTEM FOR MANUFACTURING A COMPOSITE PRODUCT AND A COMPOSITE PRODUCT
Field of the Invention
The invention relates to a method and a system for manufacturing a composite product. Further, the invention relates to a composite product and a use of the composite product. Background of the Invention
Known from prior art are different wood-polymer composites which are formed from wood-based material and polymers. Summary of the Invention
It is an object of the invention to provide a new composite product. The composite product may be a final product or an intermediate product. Another object of the invention is to disclose a new method and a system for manufacturing a composite product.
The method for manufacturing a composite product according to the present invention is characterized by what is presented in claim 61 . The composite product according to the present invention is characterized by what is presented in claims 1 and 75. The system for manufacturing a composite product is characterized by what is presented in claim 73.
Advantageously, the composite product comprises matrix material, and fiber material comprising a first fiber fraction and a second fiber fraction, and - the first fiber fraction and the second fiber fraction differ from each other chemically or dimensionally, and
the length weighted average length of the first fiber fraction is less than 0.9 times the length weighted average length of the second fiber fraction. Preferably, the first fiber fraction comprises organic natural fiber based material.
Preferably, the stiffness of the composite product times the impact properties of the composite product is at least 25 000 MN*kJ/m4.
Preferably, the width of the fibers in the first fiber fraction is between 1 .5 and 4 times the thickness of the fibers in the first fiber fraction. Preferably, the width of the fibers in the second fiber fraction is between 1 .0 and 1 .3 times the thickness of the fibers in the second fiber fraction.
Preferably, the width of the fibers in the second fiber fraction is between 5 and 60 μιτι.
Preferably, the thickness of the fibers in the second fiber fraction is between 5 and 60 μιτι.
Preferably, the width of the fibers in the first fiber fraction is between 15 and 50 μιτι.
Preferably, the thickness of the fibers in the first fiber fraction is between 5 and 18 μιτι. In an embodiment, the first fiber fraction has a length weighted average fiber length of between 0.1 and 1 .3 mm.
In an embodiment, the first fiber fraction has a length weighted average fiber length of between 0.2 and 2.8 mm.
Preferably, the second fiber fraction comprises polymer fibers. In an embodiment, the second fiber fraction comprises glass fibers. In an embodiment, the second fiber fraction comprises carbon fibers. In an embodiment, the second fiber fraction comprises viscose fibers.
In an embodiment, the composite product is a granulate or a pellet. In an embodiment, the composite product is a plate.
In an embodiment, the composite product is a product of electronics industry.
In an embodiment, the composite product is a product of an instrument, or a part of an instrument
In an embodiment, the composite product is a product of a part of audiovisual (AV) equipment. In an embodiment, the product comprises between 1 and 20 wt. % of glass fibers, calculated from the total content of the composite product.
In an embodiment, the product comprises between 1 and 20 wt. % of plastic fibers, calculated from the total content of the composite product.
In an embodiment, the composite product that is dry absorbs moisture less than 1 .5 % of the weight of the composite product in the time of 48 hours (65 % RH and 27 QC atmosphere). In an embodiment, the density of the composite product is between 0.90 and 1 .8 g/cm3.
In an embodiment, the pore volume of the composite product is under 10 %. In an embodiment, the charpy notched impact of the composite product is at least 8 kJ/m2.
In an embodiment, the second fiber fraction has a length weighted average fiber length between 1 .5 and 25 mm. In an embodiment, between 20 and 99 wt. % calculated from the total amount of fiber materials in the composite product, is included in the first fiber fraction.
In an embodiment, the length weighted average length of the first fiber fraction is less than 0.7 times the length weighted average length of the second fiber fraction.
In an embodiment, the first fiber fraction comprises chemical pulp. In an embodiment, the second fiber fraction comprises chemical pulp.
In an embodiment, the chemical pulp consists of kraft pulp.
In an embodiment, the lignin content of the first fiber fraction and/or the second fiber fraction is lower than 5 wt.%.
In an embodiment, the first fiber fraction comprises at least 50 wt. % of virgin fibers. In an embodiment, the first fiber fraction comprises wood based material.
In an embodiment, the wood based material comprises softwood.
In an embodiment, the first fiber fraction comprises organic natural fiber based non-wood material.
In an embodiment, the second fiber fraction comprises organic natural fiber based non-wood material. In an embodiment, the non-wood based material comprises straw, coconut, leaves, bark, seeds, hulls, flowers, vegetables or fruits from cotton, corn, wheat, oat, rye, barley, rice, flax, hemp, manila hemp, sisal hemp, jute, ramie, kenaf, bagasse, bamboo, or reed. In an embodiment, the first fiber fraction comprises fibers in a flake form having a width that is at least 2 times larger than the thickness of the fibers. In an embodiment, the matrix material is thermoplastic. In an embodiment, the matrix material comprises polyolefin.
In an embodiment, the melting point of the matrix material is below 260 QC.
In an embodiment, the fiber length of at least 60 wt. % of the organic natural fiber based material in the composite product is between 0.1 mm and 1 .5 mm.
In an embodiment, the length of at least 80 wt. % of the organic natural fiber based material is between 0.1 mm and 1 .5 mm, more preferably between 0.3 mm and 0.7 mm
In an embodiment, the content of the organic natural fiber based material is between 20 and 80 dry wt. % calculated from the total dry weight of the composite product. In an embodiment, the content of the matrix material is between 20 and 80 dry wt. % calculated from the total dry weight of the composite product.
In an embodiment, lignin content of the organic natural fiber based material is below 1 wt. %.
In an embodiment, the content of flake-form fiber material in the composite product is at least 30 dry wt. % calculated from the total content of the organic natural fiber based material. In an embodiment, at least 90 wt. % of the organic natural fiber based material is wood based material.
In an embodiment, the organic natural fiber based material comprises at least 80 wt. % of fiber materials having a length between 0.1 and 1 .0 mm. In an embodiment, the second fiber fraction comprises man-made fiber material.
In an embodiment, the man-made fiber material comprises mineral fibers, metal fibers, and/or man-made polymer fibers.
In an embodiment, the melting point of the man-made fiber material is at least 20 QC higher than the melting point of the matrix material. In an embodiment, the man-made fiber material comprises hollow-core fibers.
In an embodiment, the man-made fiber material comprises solid-core fibers. In an embodiment, the content of the man-made fiber material in the composite product is between 0.1 and 45 wt.%, more preferably between 1 and 20 dry wt. % calculated from the total dry weight of the composite product. In an embodiment, the composite product comprises more than one kind of man-made fiber material, and the length weighted average length of the organic natural fiber based material is less than 0.8 times the length weighted average length of the all man-made fiber materials. In an embodiment, the length weighted average length of the organic natural fiber based material is less than 0.5 times the length weighted average length of the man-made fiber materials.
In an embodiment, the length of at least 80 wt. % of the man-made fiber material is between 1 .5 mm and 10 mm.
In an embodiment, the length weighted average length of the man-made fiber material is between 2 mm and 5 mm. Advantageously, a method for manufacturing a composite product comprising matrix material and fiber material comprising a first fiber fraction and a second fiber fraction, wherein the first fiber fraction preferably comprises organic natural fiber based material, the first fiber fraction and the second fiber fraction differ from each other chemically or dimensionally, and the length weighted average length of the first fiber fraction is less than 0.9 times the length weighted average length of the second fiber fraction, comprises
adding the matrix material and the fiber material to the system, melting the matrix material at least partly and mixing the materials to form a mixture, and
- forming a composite product comprising the mixture.
In an embodiment, the moisture content of the mixture 15 before the composite product is formed is less than 7% In an embodiment, the second fiber fraction comprises solid-core fibers comprising two material layers, of which at least one comprises man-made fiber material.
In an embodiment, the fiber material and the matrix material are added to the system in the form of granulates and/or pellets.
In an embodiment, the first fiber fraction and the second fiber fraction are added to the system in the same granulates. In an embodiment, the first fiber fraction and the second fiber fraction are added to the system in separate granulates.
In an embodiment, the matrix material is thermoplastic. In an embodiment, the composite product is formed by injection moulding and/or extrusion.
In an embodiment, the composite product is formed using an extruder in which the diameter of the extruder screw in the feeding area is between 30 mm and 550 mm. In an embodiment, the temperature at which the mixture 15 is formed is lower than 220 °C.
In an embodiment, the moisture content of the organic natural fiber based material is below 7 %, preferably below 5 during the mixing.
In an embodiment, at least one mixer that is capable of heating the mixture is used in the mixing. Advantageously, a system for manufacturing a composite product comprising matrix material, and fiber material comprising a first fiber fraction and a second fiber fraction, wherein the first fiber fraction preferably comprises organic natural fiber based material, the first fiber fraction and the second fiber fraction differ from each other chemically or dimensionally, and the length weighted average length of the first fiber fraction is less than 0.9 times the length weighted average length of the second fiber fraction,
comprises
a first mixer for forming a mixture comprising said materials, means for forming a composite product comprising the mixture.
In an embodiment, the first mixer and/or the means for forming the composite product comprises an extruder.
Description of the Drawings
In the following, the invention will be described in more detail with reference to the appended drawings, in which:
Figures 1 to 3 show reduced flow chart illustrations of embodiments of the present invention, and
Figure 4a shows an example of a composite product,
Figure 4b shows an example of a final composite product, Figure 5 shows an example where the amounts of short and long fibers in the fiber materials are illustrated, and
Figures 6a to 6c show some example fibers.
Detailed Description of the Invention
In the following disclosure, all percentages are by dry weight, if not indicated otherwise.
In this application, the term "fiber length" means "the length weighted average length of fibers" or "the length of a single fiber".
In this application, the thickness is a smaller dimension than the width or is equal to the width, and the width is a smaller dimension than the length or is equal to the length.
In this application, the dimensions of fibers refer to the dimensions of a separate fiber, not to flocks or similar structures.
The following reference numbers are used in this application:
1 1 first fiber fraction,
12 matrix material,
13 second fiber fraction,
15 mixture comprising fiber material and matrix material,
15b pellets or granulates comprising the mixture 15,
39 apparatus for forming a composite product, for example an extruder or injection molding machine,
39b apparatus for forming a final product from an intermediate product, 40 composite product,
40a intermediate composite product,
40b final composite product,
50 imaginary line crossing a fiber,
51 first interface of a fiber,
52 second interface of a fiber,
53 third interface of a fiber, and 54 fourth interface of a fiber.
The mechanical properties of composite products depend on many aspects. For example, if the product comprises fiber materials and polymers, the fiber type, the fiber properties, the fiber content, the fiber length, the dispersion, and the adhesion between the fibers and the matrix material, and the mechanical properties of matrix material have an effect on the mechanical properties of the product. The stiffness of the composite product may increase if fiber materials are added to the matrix material. For example, wood and wood based cellulose fibers are typically quite short, but they may still increase the stiffness and the strength quite a lot. The length of the fibers may be critical, for example, for the impact strength. Long fibres may maintain or even improve the impact strength and increase the stiffness and strength at the same time. Therefore, in order to get a high impact strength, preferably at least some of the fibers used in the composite product are very long. However, the fiber length may decrease during the manufacturing stages of the composite product; thus, the fiber length of the fibers is often smaller in the composite product than in the raw materials. However, short fibers are also preferably used in the composite product because, among other things, the long fibers increase the friction during extrusion and injection moulding processes and a higher injection pressure is needed to fill the mould. In addition, the strength properties of the composite product may be increased if the product comprises both short and long fibers, but good processability may still be ensured.
Therefore, advantageously, a composite product comprising fibres with a bimodal fibre length distribution is produced. The short fibres may enable a high fibre content, easier processing, improved stiffness and strength. The longer fibres may further improve the strength and the stiffness and enable higher impact and melt strength. In this application, the term "length weighted average length" is calculated according to the following equation: L(average) =∑ n *Lj2/∑nj*Lj where
rij refers to the number of fibers having the same length , and
Li refers to the length of fibers.
In this application, fiber material preferably comprises first fiber fraction and second fiber fraction.
Advantageously, the first fiber fraction comprises or consists of organic natural fiber based material. Alternatively or in addition, the first fiber fraction comprises or consists of man-made fiber material. Advantageously, the second fiber fraction comprises or consists of man- made fiber material. Alternatively or in addition, the second fiber fraction comprises or consists of organic natural fiber based material.
The term "organic natural fiber based material 1 1 " refers to particles that contain cellulose. In other words, the organic natural fiber based material can originate from any plant material that contains cellulose; i.e. both wood material and non-wood material can be used.
The wood material (i.e. wood based material) can be softwood trees, such as spruce, pine, fir, larch, douglas-fir or hemlock, or hardwood trees, such as birch, aspen, poplar, alder, eucalyptus, or acacia, or a mixture of softwoods and hardwoods. Non-wood material can be agricultural residues, grasses or other plant substances such as straw, coconut, leaves, bark, seeds, hulls, flowers, vegetables or fruits from cotton, corn, wheat, oat, rye, barley, rice, flax, hemp, manila hemp, sisal hemp, jute, ramie, kenaf, bagasse, bamboo, or reed.
Advantageously, at least 30 wt.% or at least 40 wt.%, more preferably at least 50 wt.% or at least 60 wt. %, and most preferably at least 80 wt. % or at least 90 wt.% of the organic natural fiber based material in the composite product and/or in the first fiber fraction and/or in the second fiber fraction is wood based. Advantageously, at least 30 wt.% or at least 40 wt.%, more preferably at least 50 wt.% or at least 60 wt. %, and most preferably at least 80 wt. % or at least 90 wt.% of the organic natural fiber based material in the composite product and/or in the first fiber fraction and/or in the second fiber fraction comes from hardwood. In this case, preferably at least 30 wt.% or at least 40 wt.%, more preferably at least 50 wt.% or at least 60 wt. %, and most preferably at least 80 wt. % or at least 90 wt.% of the hardwood is birch and/or eucalyptus. Alternatively or in addition, at least 30 wt.% or at least 40 wt.%, more preferably at least 50 wt.% or at least 60 wt. %, and most preferably at least 80 wt. % or at least 90 wt.% of the organic natural fiber based material in the composite product and/or in the first fiber fraction and/or in the second fiber fraction comes from softwood. However, the total amount of the softwood and the hardwood in the organic natural fiber based material is not more than 100 wt. %. Preferably, at least 30 wt.% or at least 40 wt.%, more preferably at least 50 wt.% or at least 60 wt. %, and most preferably at least 80 wt. % or at least 90 wt.% of the softwood is pine or spruce.
The organic natural fiber based material can be in the form of fibers, such as floccules, single fibers, or parts of single fibers, or the organic natural fiber based material can be in the form of fiber-like particles, such as saw dust or ground material, where the material does not have an exactly spherical form, but the longest dimension of a particle is preferably less than 5 times longer than the smallest dimension.
Preferably, the organic natural fiber based material is, at least partly, in the form of fibers. Preferably at least 40 wt. % or at least 50 wt. %, more preferably at least 60 wt. % or at least 70 wt. % and most preferably at least 80 wt. % of the organic natural fiber based materials are in the form of fibers. In this application, the organic natural fiber based material having a length of at least 0.1 mm, more preferably at least 0.2 mm and most preferably at least 0.3 mm are called fibers, and smaller particles than those mentioned above are called powder or fiber-like particles. Preferably at least 70%, at least 80 % or at least 90 % of the organic natural fiber based material in the composite product and/or in the first fiber fraction and/or in the second fiber fraction has a length weighted fiber length smaller than 4 mm, smaller than 3 mm or smaller than 2.5 mm, more preferably smaller than 2.0 mm, smaller than 1 .5 mm, smaller than 1 .0 mm or smaller than 0.5 mm. Preferably, at least 70 %, at least 80 %, or at least 90 % of the organic natural fiber based material in the composite product and/or in the first fiber fraction and/or in the second fiber fraction has a length weighted fiber length of at least 0.1 mm or at least 0.2 mm, more preferably at least 0.3 mm or at least 0.4 mm. Advantageously, the fiber in the composite product and/or in the first fiber fraction and/or in the second fiber fraction has a shape ratio relating to the ratio of the fiber length to the fiber thickness being at least 5, preferably at least 10, more preferably at least 25 and most preferably at least 40. In addition or alternatively, the fiber in the composite product and/or in the first fiber fraction and/or in the second fiber fraction has a shape ratio relating to the ratio of the fiber length to the fiber thickness being preferably 1500 at the most, more preferably 1000 at the most, and most preferably 500 at the most. In an example, the fiber length of the organic natural fiber based material is measured using a so-called Fiberlab measuring device, manufactured by Metso.
Advantageously, the organic natural fiber based material 1 1 in the composite product and/or in the first fiber fraction and/or in the second fiber fraction comprises fibers in a flake form. Flakes are fibers having a width that is at least 2 times greater than the thickness of the fibers. Advantageously, the width of the flake is at least 2, preferably at least 2.5, and more preferable at least 3 times the thickness of the flake. Preferably, the flakes have a thickness between 1 micron and 30 micrometers, and more preferably the thickness of the flakes varies from 2 microns to 20 micrometers. Most preferably, the thickness of the flakes is smaller than 15 μιτι, more preferably smaller than 10 μιτι and most preferably smaller than 7 μιη. In one embodiment, the width of the flake is smaller than 500 μιη, preferably smaller than 200 μιτι, and more preferably smaller than 50 μιτι. Preferably, the aspect ratio relating to the ratio of the length to the width is between 10 and 100. Preferably, the aspect ratio relating to the ratio of the length to the thickness is lower than 1500 or lower than 1000, more preferably lower than 500 and most preferably between 25 and 300. In one embodiment, the length of the flake is at least 10 times the width of the flake. In one embodiment the flake has a tabular shape. In one embodiment the flake has a platy shape. In one embodiment, the organic natural fiber based material contains flake-form fiber material at least 30 dry wt. %, preferably at least 50 dry wt. % and more preferably at least 70 dry wt. % of the total amount of the organic natural fiber based material.
The organic natural fiber based material may comprise mechanically treated and/or chemically treated fibers and/or fiber-like particles.
The mechanically treated organic natural fiber based material may comprise, among other things, wood flour, saw dust, chip material, and/or mechanical pulp such as TMP (thermo mechanical pulp), GW (groundwood pulp) / SGW (stone groundwood pulp), PGW (pressure groundwood pulp), RMP (refiner mechanical pulp), and/or CTMP (chemithermomechanical pulp). The mechanically treated organic natural fiber based material preferably comprises or consists of wood particles, such as wood fibers, but it may also comprise or consist of non-wood material. The mechanically treated organic natural fiber based material may comprise recycled and/or virgin particles, such as fibers or fiber-like particles. Advantageously at least 30 wt. % or at least 40 wt. %, more preferably at least 50 wt. % or at least 60 wt. %, and most preferably at least 80 wt. % or at least 90 wt. % of the organic natural fiber based material used in the composite product and/or in the first fiber fraction and/or in the second fiber fraction are virgin. Typically, for example, wood plastic composites (WPC) comprise saw dust or at least other mechanically treated wood or plant particles as the main organic natural fiber based material.
The chemically treated organic natural fiber based material in the composite product and/or in the first fiber fraction and/or in the second fiber fraction preferably comprises or consists of chemical pulp. The chemical pulp may come, for example, from a kraft process or a sulphite process, but also other chemical processes may be used, such as a soda pulping process. Preferably, the chemical pulp comes from the kraft process, also called as sulphate cooking process, which uses a mixture of sodium hydroxide (NaOH) and sodium sulphide (Na2S). The chemically treated organic natural fiber based material in the composite product and/or in the first fiber fraction and/or in the second fiber fraction preferably comprises or consists of wood based cellulose, but it may also be non-wood material. The chemically treated organic natural fiber based material may comprise recycled and/or virgin fibers and/or fiber-like particles. Advantageously, at least 30 wt. % or at least 40 wt. %, more preferably at least 50 wt. % or at least 60 wt. %, and most preferably at least 80 wt. % or at least 90 wt. % of the organic natural fiber based material used in the composite product and/or in the first fiber fraction and/or in the second fiber fraction is chemically treated particles. Advantageously, at least 30 wt. % or at least 40 wt. %, more preferably at least 50 wt. % or at least 60 wt. %, and most preferably at least 80 wt. % or at least 90 wt. % of the chemically treated particles used in the composite product and/or in the first fiber fraction and/or in the second fiber fraction come from kraft process. Advantageously, the lignin content of the chemically treated pulp is lower than 15 wt.%, preferably lower than 10 wt. % or lower than 5 wt.%, more preferably lower than 3 wt. %, lower than 2 wt. % or lower than 1 wt.% and most preferably lower than 0.5 wt.%. Preferably, the alfa cellulose content of the chemically treated pulp is above 50 wt.%, preferably above 60 wt.%, more preferably above 70 wt.% and most preferably above 72 wt. % or above 75 wt.%. Advantageously, the alfa cellulose content of the chemically treated pulp is below 99 wt.%, preferable below 90 wt.%, more preferably below 85 wt.% and most preferably below 80 wt.%. Advantageously at least 30 wt. % or at least 40 wt. %, more preferably at least 50 wt. % or at least 60 wt. %, and most preferably at least 80 wt. % or at least 90 wt. % of the organic natural fiber based material in the composite product and/or in the first fiber fraction and/or in the second fiber fraction are virgin.
Advantageously, lignin content of the organic natural fiber based material in the composite product and/or in the first fiber fraction and/or in the second fiber fraction is lower than 15 wt.%, preferably lower than 10 wt. % or lower than 5 wt.%, more preferably lower than 3 wt. % or lower than 1 wt.% and most preferably lower than 0.5 wt.%. The lignin content may be low due to delignification process, or the lignin content of the organic natural fiber based material may be naturally on a low level. Advantageously, the lignin content of the organic natural fiber based material is at least 0.05 wt. %, more preferably at least 0.10 wt. % or at least 0.2 wt. % and most preferably at least 0.3 wt. %. In an embodiment, the lignin content of the organic natural material is higher than 3 wt. %, higher than 5 wt. % or higher than 10 wt. %.
In an embodiment, at least part of the organic natural fiber based starting material is in the form of a paper sheet or web, a board sheet or web, a pulp sheet or web, or compacted fiber matrix or pieces of compacted fibers and their combinations. Advantageously, the organic natural fiber based starting material is treated, for example refined, to obtain the organic natural fiber based material used in this invention.
In an embodiment, at least part of the organic natural fiber based starting material is in the form of large fibers or fiber bundles, paper chaff, pulp chaff, crushed pulp material, derivates thereof and their combinations.
The content of the organic natural fiber based material is calculated as the total content of the untreated and/or in the above-mentioned way mechanically treated, and/or in the above-mentioned way chemically treated organic natural fiber based material in the system or the product, and it does not comprise man-made fibers, such as viscose fibers.
The man-made fiber material may comprise, for example, mineral fibers and/or metal fibers, such as
E-glass,
S-glass,
Carbon,
Boron
- Ceramic,
Steel,
Aluminium, and/or
Titanium.
In addition or alternatively, the man-made fiber material may comprise, for example, man-made polymer fibers, such as
Aramid (e.g. Kevlar), LCP-fiber (e.g. Vectran),
Polyester,
Polyamide,
Polyimide,
- Polyetheretherketone, and/or
Polysulfone.
The man-made fiber may be straight or it may be crimped, i.e. have angles. The man-made fiber material may comprise or consist of synthetic plastic material(s).
Advantageously, the man-made fiber material comprises viscose fibers, polymer fibers, glass fibers, other inorganic fibers and/or carbon fibers. Advantageously at least 50 wt. % or at least 60 wt. %, more preferably at least 75 wt. % or at least 85 wt. %, and most preferably at least 90 wt. %, at least 95 wt. % or at least 98 wt. % of the man-made fiber material is viscose fibers, polymer fibers, glass fibers, other inorganic fibers and/or carbon fibers. Most preferably the man-made fiber material comprises glass fibers and/or polymer fibers. Therefore, advantageously at least 50 wt. % or at least 60 wt. %, more preferably at least 75 wt. % or at least 85 wt. %, and most preferably at least 90 wt. %, at least 95 wt. % or at least 98 wt. % of the man-made fiber material is glass fibers and/or polymer fibers. Advantageously, the melting point of man-made fiber material is at least 180QC, more preferably at least 210QC, or at least 240QC and most preferably at least 270QC or at least 300QC.
Advantageously, the glass transition temperature of the man-made fiber material is at least 180QC, more preferably at least 210QC, or at least 240QC and most preferably at least 270QC or at least 300QC.
Advantageously, the melting point and/or the glass transition temperature of all the components of the man-made fiber material and/or the second fiber fraction is at least 20 QC, or at least 30 QC higher, more preferably at least 40 QC or at least 50 QC higher, and most preferably at least 60 QC or at least 70 QC higher than said property of the matrix material, especially in the case of the man-made polymer fibers. Preferably, if the product comprises the man- made polymer fibers, they are in the form of fibers not only during the manufacturing process but also in the manufactured composite product.
In an embodiment, the man-made fiber comprises fibers having at least two different kinds of raw material layers. In this case, the man-made fiber preferably comprises at least one inner material and at least one outer material. The inner material is preferably made of man-made fiber material, and the outer material may comprise the man-made fiber material and/or the matrix material. In an example embodiment, this kind of man-made fiber material comprises inner material consisting of PET, and outer material consisting of the matrix material. In an embodiment, the man-made fiber is a hollow-core fiber. In this case, the man-made fiber preferably comprises outer material comprising or consisting of man-made fiber material.
In an embodiment, the man-made fiber material comprises a solid-core fibers comprising, for example, one or two material layer(s).
In this application, the "matrix material 12" is preferably material which can be formed several times into a new shape when it is heated. This material keeps its new shape after cooling and it then flows very slowly, or it does not flow at all. The matrix material has at least one repeat unit, and the molecular weight of the matrix material is higher than 18 g/mol, preferably higher than 100 g/mol, higher than 500 g/mol, or higher than 1000 g/mol, more preferably higher than 10 000 g/mol or higher than 100 000 g/mol. The matrix material 12 preferably comprises thermoplastic material; hence, the matrix material includes thermoplastic components. Advantageously, the amount of the thermoplastic material in the matrix material is at least 80 wt. %, more preferably at least 90 wt. %, and most preferably at least 95 wt. %. Advantageously, the matrix material comprises at least one crystalline polymer and/or at least one non-crystalline polymer, and/or at least one crystalline oligomer and/or at least one non-crystalline oligomer. Advantageously, the matrix material comprises, in addition to the thermoplastic polymers, polymeric coupling agent(s). The polymeric coupling agent preferably contains a moiety or moieties which are reactive or at least compatible with the matrix material, and a moiety or moieties which are reactive or at least compatible with the organic natural fiber based material. If the matrix material is non-polar, the moiety or moieties which are reactive or compatible with the matrix material are preferably non-polar. If the matrix material is polar, the moiety or moieties which are reactive or compatible with the matrix material is/are preferably polar. Preferably, the polymeric coupling agent contains the same repeat units as the matrix material used. Advantageously at least 30 wt. % or at least 40 wt. %, more preferably at least 50 wt. % or at least 60 wt. %, and most preferably at least 80 wt. % or at least 85 wt. % of the moieties of the polymeric coupling agent are chemically the same as in the matrix material. Advantageously said moiety or moieties which is/are reactive or at least compatible with the organic natural fiber based material comprise(s) anhydride(s), acid(s), alcohol(s), isocyanate(s), and/or aldehyde(s). Preferably, the coupling agent is an acrylic acid grafted polymer. Alternatively or in addition, the coupling agent is a methacrylic acid grafted polymer. Most preferably, the coupling agent comprises or consists of a maleinic acid anhydride grafted polymer. The coupling agent can, in principle, be any chemical which is capable of improving the adhesion between the two main components. This means that it may contain components which are known to be reactive or compatible with matrix material and components, which are known to be reactive or compatible with the organic natural fiber based material.
Advantageously the coupling agent comprises or consists of
anhydrides, preferably maleic anhydride (MA),
- polymers and/or copolymers, preferably maleated polyethylene
(MAPE), Maleated polypropylene (MAPP), Styrene-ethylene- butylene-styrene/maleic anhydride (SEBS-MA), and/or Styrene/maleic anhydride (SMA), and/or
organic-inorganic agents, preferably silanes and/or alkoxysilanes. Preferably, at least 50 wt. %, at least 60 wt. %, more preferably at least 70 wt. % or at least 80 wt. % and most preferably at least 90 wt. % of the coupling agents used are
anhydrides, preferably maleic anhydride (MA), and/or - polymers and/or copolymers, preferably maleated polyethylene
(MAPE), Maleated polypropylene (MAPP), Styrene-ethylene- butylene-styrene/maleic anhydride (SEBS-MA), and/or
Styrene/maleic anhydride (SMA), and/or
Organic-inorganic agents, preferably silanes and/or alkoxysilanes.
Advantageously, the matrix material 12 comprises thermoplastic polymer based matrix material and/or thermoplastic oligomer based matrix material. Thermoplastic polymers are often solid at a low temperature and they form a viscose polymer melt at elevated temperatures. Typically, the viscosity of these polymer decreases when temperature is increased, and the polymers flow and wet the surfaces more easily. When thermoplastic composites are produced, the polymer is heated in order to melt the polymer, and other components of the composites are mixed with the polymer melt. It is often easy to mix these other components with the polymer when the viscosity of the polymer is low, which means that the temperature of the polymer melt is high.
The matrix material is, at least partly, in molten form wherein
- the organic natural material can adhere to the matrix material, and/or
- the melt flow index of the material can be measured (according to standard ISO 1 133 (valid in 201 1 )), and/or
- the organic natural fibre material can adhere to the surfaces of matrix material particles.
The polymer based matrix material contains one or more polymers, and the oligomer based matrix material contains one or more oligomers. The total content of the polymers and oligomers calculated from the total amount of the matrix material is preferably at least 80 wt. %, at least 85 wt. %, at least 90 wt. %, at least 95 wt. % or at least 98 wt. %. If the matrix material comprises polymer, it may be any suitable polymer or polymer composition. Advantageously, the matrix material contains at least 50 wt.%, at least 60 wt.%, more preferably at least 70 wt. %, or at least 80 wt.%, and most preferably at least 90 wt.% or at least 95 wt.% of:
- polyolefin, e.g. polyethylene and polypropylene including copolymers,
polystyrene,
polyamide,
polyester,
- ABS (acrylic nitrile butadiene styrene copolymer),
polycarbonate,
biopolymer, e.g. polylactide,
biodegradable polymer,
bio-based polymer,
- thermoplastic elastomer,
polysaccharides,
lignin, and/or
their derivatives. The matrix material 12 may contain one or more polymer material components. Advantageously, at least one polymer is selected from the group consisting of polyethylene, polypropylene and their combinations. Advantageously, the content of polypropylene and polyethylene in the matrix material is at least 50 wt.%, at least 60 wt.%, at least 70 wt. %, at least 80 wt.%, at least 90 wt.% or at least 95 wt.%.
The matrix material may be homo polymer, copolymer and/or random copolymer. Advantageously, the melting point of the matrix material is below 260 QC, below 240 QC, or below 220 QC, more preferably below 200 QC, or below 180 QC, and most preferably below 150 QC. Advantageously, the glass transition temperature of the matrix material is below 260QC, below 240QC, or below 220QC, more preferably below 200QC, or below 180QC, and most preferably below 150 °-C. Advantageously, melt flow rate, MFR, of the matrix material is below 1000 g/10 min (230QC, 2.16 kg defined by ISO 1 133, valid 201 1 ), more preferably 0.1 - 200 g/10 min, most preferably 0.3 - 150 g/10 min. Advantageously, the melt flow rate, MFR, of the matrix material is higher than 0.1 g/10 min (230QC, 2.16 kg defined by ISO 1 133, valid 201 1 ), more preferably higher than 1 g/10 min, most preferably higher than 3 g/10 min.
In this application, the term "first fiber fraction 1 1 " refers to a material fraction consisting of fiber material.
Preferably, the fiber length of a fiber included in the first fiber fraction is at least 0.1 mm, more preferably at least 0.2 mm, and most preferably at least 0.3 mm, and preferably shorter than 1 .5 mm, more preferably shorter than 1 .2 mm and most preferably shorter than 1 .0 mm.
Preferably, the width of fibers in the first fiber fraction is between 15 and 50 μιη, more preferably between 20 and 40 μιτι, and most preferably between 22 and 35 μιτι. Preferably, the thickness of fibers in the first fiber fraction is between 5 and 18 μιη, more preferably between 8 and 15 μιτι.
Preferably, the width of fibers in the first fiber fraction is between 1 .5 and 4 times, more preferably between 2 and 3 times the thickness of the fibers in the first fiber fraction.
Advantageously, the first fiber fraction comprises at least 50 wt. % or at least 60 wt. %, more preferably at least 70 wt. %, or at least 80 wt. %, and most preferably at least 90 wt. % or at least 95 wt. %, or exactly 100 wt. % of organic natural fiber based material. In addition, preferably at least 50 wt. % or at least 60 wt. %, more preferably at least 70 wt. %, or at least 80 wt. %, and most preferably at least 90 wt. % or at least 95 wt. %, or exactly 100 wt. % of the all organic natural fiber based materials in the composite product 40 is included in the first fiber fraction. Alternatively or in addition, the first fiber fraction may comprise man-made fiber material. In this case, the first fiber fraction preferably comprises at least 20 wt. % or at least 40 wt. %, more preferably at least 60 wt. %, or at least 80 wt. %, and most preferably at least 90 wt. % or at least 95 wt. %, or exactly 100 wt. % of man-made fiber material.
Most advantageously, the fiber material, preferably the organic natural fiber based material, having a fiber length of at least 0.1 mm, more preferably at least 0.2 mm, and most preferably at least 0.3 mm, and preferably shorter than 1 .5 mm, more preferably shorter than 1 .2 mm and most preferably shorter than 1 .0 mm is included in the first fiber fraction.
Advantageously, the first fiber fraction has a length weighted average fiber length of between 0.1 and 1 .3 mm, or between 0.15 and 1 .0 mm, more preferably between 0.2 and 0.8 mm, and most preferably between 0.3 and 0.7 mm. In an embodiment, at least 80 wt. %, more preferably at least 90 wt. % and most preferably at least 95 wt. %, or exactly 100 wt. % of the fibers in the first fiber fraction have a fiber length of at least 0.1 mm, more preferably at least 0.2 mm and most preferably at least 0.3 mm, and preferably shorter than 1 .5 mm, more preferably less than 1 .2 mm, and most preferably shorter than 1 .0 mm.
In an another example, the first fiber fraction has a length weighted average fiber length of between 0.2 and 2.8 mm, or between 0.5 and 2.5 mm, more preferably between 0.8 and 2.2 mm, and most preferably between 1 .2 and 1 .8 mm. In this embodiment, preferably at least 80 wt. %, more preferably at least 90 wt. % and most preferably at least 95 wt. %, or exactly 100 wt. % of the fibers in the first fiber fraction have a fiber length of at least 0.1 mm, more preferably at least 0.2 mm and most preferably at least 0.3 mm, and preferably shorter than 2.8 mm, more preferably shorter than 2.2 mm, and most preferably shorter than 1 .8 mm.
In this application, the term "second fiber fraction 13" refers to a fraction consisting of fiber material. Preferably, the fiber length of a fiber included in the second fiber fraction is at least 1 .5 mm, more preferably at least 2.0 mm and most preferably at least 2.5 mm, and preferably shorter than 15 mm, more preferably shorter than 10 mm or less than 7 mm, and most preferably shorter than 5 mm.
The second fiber fraction preferably comprises or consists of man-made fibres. Advantageously, at least 50 wt. % or at least 60 wt. %, more preferably at least 70 wt. %, or at least 80 wt. %, and most preferably at least 90 wt. % or at least 95 wt. %, or exactly 100 wt. % of the fibers in the second fiber fraction are man-made fibers. In addition, preferably at least 70 wt. % or at least 80 wt. %, more preferably at least 90 wt. %, or at least 95 wt. %, and most preferably at least 99 wt. % or exactly 100 wt. % of the man-made fibers are included in the second fiber fraction. Alternatively or in addition, the second fiber fraction may comprise organic natural fiber material. In this case, at least 20 wt. % or at least 40 wt. %, more preferably at least 60 wt. %, or at least 80 wt. %, and most preferably at least 90 wt. % or at least 95 wt. %, or exactly 100 wt. % of the fibers in the second fiber fraction are organic natural fiber based material.
Preferably, the width of fibers in the second fiber fraction is between 5 and 60 μιη, more preferably between 10 and 30 μιτι.
Preferably, the thickness of fibers in the second fiber fraction is between 5 and 60 μιτι, more preferably between 10 and 30 μιτι.
Preferably, the width of fibers in the second fiber fraction is between 0.7 and 1 .3 times, more preferably between 0.8 and 1 .2 times, and most preferably between 0.9 and 1 .1 times the thickness of the fibers in the second fiber fraction.
Most advantageously, the man-made fiber material having a fiber length of at least 1 .5 mm, or at least 2.0 mm, more preferably at least 2.3 mm, at least 2.5 mm, or at least 2.8 mm and most preferably at least 3 mm, or at least 4 mm, and preferably less than 15 mm, more preferably shorter than 10 mm or shorter than 7 mm, and most preferably shorter than 5 mm is included in the second fiber fraction.
Advantageously, the second fiber fraction has a length weighted average fiber length of between 1 .5 and 15 mm, more preferably between 2 and 10 mm, and most preferably between 2.5 and 5 mm. Advantageously, at least 80 wt. %, more preferably at least 90 wt. % and most preferably at least 95 wt. %, or exactly 100 wt. % of the fibers in the second fiber fraction have a fiber length of at least 1 .5 mm, more preferably at least 2.0 mm and most preferably at least 2.5 mm, and preferably shorter than 15 mm, more preferably shorter than 10 mm or less than 7 mm, and most preferably shorter than 5 mm.
Advantageously, between 20 and 99 wt. %, or between 30 and 98 wt. %, more preferably between 40 and 95 wt. %, or between 50 and 90 wt. %, or between 60 and 87 wt. %, and most preferably between 70 and 85 wt. %, or between 75 and 83 wt. % of the fiber materials 1 1 , 13, calculated from the total amount of fiber materials in the composite product, are included in the first fiber fraction, and the other fiber materials are preferably included in the second fiber fraction
composite production. Becaus
Advantageously, the length weighted average length of the first fiber fraction is less than 0.9 times, less than 0.8 times or less than 0.7 times, more preferably less than 0.5 times or less than 0.4 times, and most preferably less than 0.3 times, less than 0.2 times, or less than 0.1 times the length weighted average length of the second fiber fraction. For example, if the length weighted average length of the second fiber fraction is 2.5 mm, the length weighted average length of the first fiber fraction is most preferably less than 0.5 mm.
Advantageously, the length weighted fiber length of the second fiber fraction is at least 0.1 mm greater or at least 0.2 mm greater, more preferably at least 0.4 mm greater, at least 0.6 mm greater, or at least 0.8 mm greater, and most preferably at least 1 .0 mm greater, at least 1 .1 mm greater, or at least 1 .2 mm greater than the length weighted fiber length of the first fiber fraction. Advantageously, the length weighted average length of the second fiber fraction is at least 1 .25 times or at least 1 .5 times, more preferably at least 2 times, or at least 2.5 times, and most preferably at least 3 times, at least 4 times, or at least 5 times the length weighted average length of the first fiber fraction. For example, if the length weighted average length of the first fiber fraction is 0.5 mm, the length weighted average length of the second fiber fraction is most preferably at least 2.5 mm.
Advantageously, at least 50 wt. %, or at least 60 wt. %, more preferably at least 70 wt. % or at least 80 wt. %, and most preferably at least 85 wt. % or at least 90 wt. % of fibers of the fiber materials 1 1 , 13 have fiber length between 0.1 and 1 .3 mm or between 2 and 10 mm, more preferably between 0.2 and 1 .2 mm or between 2.5 and 7 mm, and most preferably between 0.3 and 1 .0 mm or between 3 and 5 mm.
Preferably, the second fiber fraction comprises at least one kind of man- made fiber material. In an embodiment, the above mentioned numbers and ranges relating to the second fiber fraction are calculated using one, two, or three kinds of man-made fiber material. Most preferably, the above mentioned numbers and ranges are calculated from the total amount of the man-made fiber material(s).
The first fiber fraction may comprise man-made fiber material. Advantageously the first fiber fraction comprises organic natural fiber based material. In an embodiment, the first fiber fraction comprises or consists of wood based organic natural fiber based material, and the second fiber fraction comprises or consists of non-wood based organic natural fiber based material, such as hemp. In an embodiment, the first fiber fraction may comprise or consist of wood based organic natural fiber based material, and the second fiber fraction may comprise or consist of wood based organic natural fiber based material.
In an embodiment, the first fiber fraction may comprise or consist of non- wood based organic natural fiber based material, and the second fiber fraction may comprise or consist of wood based organic natural fiber based material.
In an embodiment, the first fiber fraction may comprise or consist of non- wood based organic natural fiber based material, and the second fiber fraction may comprise or consist of non-wood based organic natural fiber based material.
The fibers of the composite orientate during manufacturing processes. Often, the direction of the orientation is the same as the flow direction of the composite. In any case, the average orientation direction can be calculated for the composite by measuring the direction of individual fibers and calculating the average orientation. The orientation may be calculated from a small cube which typically has dimensions smaller than 2 mm, more preferably smaller than 1 mm and most preferably smaller than 0.5 mm. The orientation of fibers is typically not uniform, which means that the fibers have some average difference angle to the average orientation direction. The average difference angle depends on the fiber properties and the flow during the composite production. Because the orientation depends on the fiber properties, the first and second fiber fractions can have different average difference angles to the average orientation direction.
Advantageously, the orientation of the fibers of the second fiber fraction is at least 1 %, or at least 3%, more preferably at least 5% or at least 7%, and most preferably at least 10%, at least 15%, or at least 17% greater than the orientation of the fibers of the first fiber fraction. This may give the composite product better strength properties.
In an embodiment, the second fiber fraction comprises or consists of organic natural fiber based material. In this case, preferably the organic natural fiber based material having a length shorter than 1 .5 mm is included in the first fiber fraction, and the organic natural fiber based material having a length at least 1 .5 mm is included in the second fiber fraction. In one embodiment, chemical(s) are used in order to improve adhesion and, hence, the properties of the composite product. Preferably lubricant(s), waxe(s), compatibilization agent(s), ionic surfactant(s), non-ionic surfactant(s), silane(s), acid anhydride(s) and/or carboxylic acid(s) are used for the chemical pretreatment. Alternatively or in addition, another chemical(s) which improves the wetting of fibers or adhesion between the organic natural fiber based material and the matrix material may be used, especially if the chemical is in liquid form or in gas form or in melt form below temperatures at which the matrix material is in solid form.
Suitable and desired additives can be added into the organic natural fiber based material, the matrix material and/or the mixture comprising the matrix material and the organic natural fiber based material. Advantageously, at least one additive comprising
property enhancers,
coupling agent,
adhesion promoter,
lubricant,
rheology modifiers,
releaser agent,
fire retardant,
coloring agent,
anti-mildew compound,
protective agent,
antioxidant,
uv-stabilizer,
foaming agent,
curing agent,
Halloysite (e.g. Dragonite),
High aspect ratio talc,
Nucleants (e.g. Hyperform, MPM 2000),
Nanoclays,
coagent, and/or
catalyst
is used.
Advantageously, at least one filler comprising fibrous material, organic fillers like starch or protein or some organic residues, inorganic fillers, powdery reinforcements, calcium carbonate and/or talc is used. The total content of the fillers is preferably lower than 50 wt. % or lower than 40 wt. %, more preferably lower than 30 wt. % or lower than 20 wt. %, and most preferably lower than 10 wt. % calculated from the total weight of the composite product.
Advantageously, at least one additive and/or at least one filler are added into the mixture comprising the fiber material and the matrix material. Most advantageously, the coupling agent is a polymeric coupling agent which is included in the matrix material.
Figures 1 to 6 show some example embodiments of the present invention.
Figures 1 to 3 show reduced flow chart illustrations of embodiments of the present invention.
In Fig. 1 , a mixture 15, 15b comprising fiber materials 1 1 , 13 and matrix material 12 are fed into the system. An apparatus 39 is used to form the composite product 40, 40a, 40b comprising the mixture.
In Fig. 2, the first fiber fraction 1 1 , the second fiber fraction 13, and the matrix material 12 are mixed with each other to form a mixture 15. The mixing may be implemented in an apparatus 30 or in a separate mixer. In the case of the separate mixer, the mixture is conveyed to the apparatus 39 in order to form the composite product 40.
In Fig. 3, an intermediate product 40a, such as a plate, is treated in an apparatus 39b in order to form a final product 40b from the intermediate product 40a.
Figure 5 shows an example embodiment of the present invention, in which the amount of short fibers and long fibers are illustrated. In this figure, the first fiber fraction 1 1 comprises short fibers and the second fiber fraction comprises long fibers 13, and the amount of the short fibers is greater than the amount of the long fibers. Advantageously, the system according to the present invention comprises at least an apparatus 39 for forming a composite product comprising the fiber materials 1 1 , 13 and the matrix material 12. Advantageously, at least one mixer that is capable of heating the matrix material is used in the invention. Therefore, the system preferably comprises a mixer to form a mixture comprising the fiber material 1 1 , 13, and the matrix material 12. The mixer preferably comprises a heating section. The mixture 15 may be formed, for example, from granulates or pellets. The mixer may be a part of the apparatus 39 for forming a composite product, or it may be a separate apparatus.
The composite product 40 and compounding of the materials are preferably formed with an extruder; hence, the apparatus 39 for forming the composite product 40, 40a, 40b is preferably an extruder. Extruders can be divided into single, twin or multiple screw machines. The single screw can be with a smooth, grooved or pin barrel machine. The twin screw extruder can be a conical co-rotating twin screw extruder, a conical counter-rotating twin screw extruder, a parallel co-rotating twin screw extruder, or a parallel counter- rotating twin screw extruder. The multiple screw extruders can be with a rotating or static center shaft.
In the case of the extrusion, any suitable single-screw extruder or twin-screw extruder, such as a counter-rotating twin-screw extruder or a co-rotating twin- screw extruder, may be used. The twin-screw extruder can have parallel or conical screw configuration.
In an example, the melt of the mixture 15 comprising the fiber materials and the matrix material is conveyed to a co-rotating parallel twin screw extruder. The screw volume can be, for example, from 4 to 8 times larger at the beginning of the screw than at the end of the extruder.
Feeding of the main components, i.e. the matrix material and the fiber materials, may be more difficult, if the size of machines used for the process is too small. In addition, very large sized machines may cause a poorer mixing effect or other disadvantage(s). Therefore, if an extruder is used, the diameter of the extruder screw in the feeding area is advantageously at least 30 mm, at least 40 mm, or at least 50 mm, more preferably at least 60 mm or at least 70 mm, and the most preferably at least 90 mm or at least 1 10 mm. In addition or alternatively, the diameter of the extruder screw in the feeding area is preferably not larger than 550 mm or not larger than 500 mm, more preferably not larger than 450 mm or not larger than 400 mm, and most preferably not more than 350 mm or not more than 300 mm. If a batch process is used instead of the extruder or another continuous process, the free volume used is preferably at least 200 liters, at least 400 liters or at least 500 liters, more preferably at least 600 liters or at least 800 liters, and most preferably at least 1000 liters or at least 1500 liters.
Advantageously the production capacity of the apparatus used for the manufacturing process is at least 300 kg/h or at least 400 kg/h, more preferably at least 500 kg/h or at least 700 kg/h, and most preferably at least 1000 kg/h or at least 1500 kg/h.
The raw materials 1 1 , 12, 13 of the composite product 40, 40a, 40b may be, for example, in separate particles, or in separate pellets or in separate granulates, i.e. the raw materials are not mixed with each other in any pre- treatment step, or the raw materials 1 1 , 12, 13 may be in the form of a mixture 15 comprising the raw materials 1 1 , 12, 13, or in the form of pellets or granulates 15b comprising the mixture 15. Advantageously, the quantity and/or the content of the raw materials 1 1 , 12, 13 is selected according to the predetermined quantity of the raw materials in the final product.
In an embodiment, the first fiber fraction is mixed together with the matrix material, and/or the second fiber fraction is mixed together with the matrix material in the raw materials. In an embodiment, the raw materials comprise the first fiber fraction, the second fiber fraction, and/or the matrix material, which are all in separate pellets and/or granulates.
In addition or alternatively, the composite product 40 and/or compounding of the materials can be formed with mixers such as a batch type internal mixer, an internal mixer, a heating mixer, a heating-cooling mixer, or z-blade mixer, or with any mixing device where matrix material is melted with friction and/or internal and/or external heat and fibers are incorporated to the matrix material and other components. The mixing can be a batch or continuous process. The mixer preferably comprises a section in which at least some of the moisture coming from the raw materials can be removed. The fiber materials 1 1 , 13 and the matrix material 12 can be mixed and agglomerated to form a homogeneous or substantially homogeneous mixture. The fiber content may be adjustable within a wide range, and high contents may be easy to achieve.
The composite product 40 and compounding of the materials can be formed with any of these or a combination of these and some other process steps. Any of the mixers or extruders might contain some pre or post processing directly included in the extruder or mixer or by connecting shortly before or after the extruder. Advantageously, shredding, drying, and/or mixing are performed in a continuous process directly connected to extruder.
Advantageously, the method according to the present invention comprises at least some of the following steps:
adding the matrix material 12, material of the first fiber fraction, and material of the second fiber fraction to the system, melting the matrix material 12 at least partly, and mixing the fiber materials and the matrix material 12 to form a mixture 15, and
forming a composite product comprising the mixture 15.
Advantageously, the temperature in the above mentioned process stage, in which the mixture 15 is formed, is lower than 220 °C, more preferably lower than 200 °C, and most preferably lower than 180 °C.
Advantageously, the composite product is manufactured by injection moulding, film casting, blow moulding, rotomoulding, thermoforming, compression moulding, re-extrusion, profile extrusion, sheet extrusion, film extrusion, coextrusion and/or fiber extrusion. Advantageously, the composite product is formed by injection moulding, and/or extrusion, and/or pultrusion. In one embodiment, the organic natural fiber based material and/or the man- made fiber material is/are mixed with the matrix material and additives before adding the mixture, for example, into the extruder.
In an embodiment, the composite product is a final product 40b. In another embodiment, the composite product is an intermediate product 40a, such as a plate that is used to form the final product. In an embodiment, the composite product 40, preferably the intermediate product 40a, is a granulate and/or a pellet. In this case, the size of the granulate and/or the pellet is preferably between 5 and 25 mm, more preferably at least 6 mm or at least 8 mm, and most preferably between 10 and 20 mm.
The matrix material 12 is arranged at least partly in the form of melt at least in the step in which the composite product 40, 40a, 40b is formed. The fiber materials 1 1 , 13 are mixed with the melted matrix material to form a mixture comprising at least said fiber materials and the matrix material. Matrix material is often melted mainly with friction, but some external heat can be used. Preferably, the material of the second fiber fraction 13 does not melt in the manufacturing process. The composite forming stage may be a part of a continuous process. The invention may provide composite products with good mechanical properties.
Figure 4a shows a side projection of an example intermediate composite product. In this case, the intermediate composite product is a plate.
Figure 4b shows an example of a final composite product. In this case, the final composite product is a shoehorn. In Figure 4 shows several shoehorns with different shades/colors. In one embodiment, the composite product 40, 40a, 40b is formed from the mixture comprising the fiber materials, and the matrix material. The moisture content of the mixture 15 before the composite product is formed is preferably less than 7%, less than 6%, less than 5%, less than 4%, or less than 3%, more preferably less than 2.5%, less than 2.0%, less than 1 .5% or less than 1 .0%, and most preferably less than 0.8%, less than 0.5%, less than 0.2%, or less than 0.1 %.
In an embodiment, the first fiber fraction 1 1 , the second fiber fraction 13, and the matrix material 12 are fed to the system separately. In another embodiment, the first fiber fraction 1 1 , the second fiber fraction 13, and the matrix material 12 are fed to the system together.
Advantageously, the fiber materials and the matrix material are added to the system in the form of granulates and/or pellets. This kind of pre-granulation may be important when organic natural fiber based material is used. In an embodiment, the matrix material comprises matrix material, which is added to the process in the form of powder and/or fibers.
In an embodiment, the first fiber fraction, the second fiber fraction, and/or the matrix material are fed to the system in separate granulates and/or pellets, and/or they may be fed to the system with each other in same granulates and/or a pellets.
Advantageously, the pellet and/or the granulate fed to the system comprises or consists of the first fiber fraction and the matrix material. Alternatively or in addition, the pellet and/or the granulate comprises or consists of the second fiber fraction and the matrix material. Alternatively or in addition, the pellet and/or the granulate comprises or consists of the second fiber fraction, the first fiber fraction, and the matrix material.
The granulates or pellets can be manufactured with different methods. The composite particles are preferably formed by a granulation method, a pelleting method, an agglomeration method or their combinations. In one embodiment, the granulation is carried out by means of a method selected from the group consisting of water ring, underwater pelleting, air cooled, hot face strand, and their combinations. In one embodiment the granulation is made under water. In one embodiment the granulation is carried out by means of counterpressure, e.g. with an underwater method. The simplest way to produce natural fiber-polymer granulates is to use one machine or one machine combination which compounds material components and forms this material to granulates. One example of this kind of a machine is a compounding twin screw extruder with a granulation tool.
In one embodiment, the granulates are finish-treated. Finish-treatment for granulates comprises, for example, drying, dust removing, classification and/or packing.
Advantageously, the composite product 40 is in the form of a plate. This kind of a composite product 40 is typically an intermediate composite product 40a which is formed into a final composite product 40b afterwards.
In an embodiment, the composite product 40 is a final product 40b. The final product may be manufactured from the intermediate composite product 40a by any suitable method, such as molding, extrusion, thermoforming, compression molding, vacuum forming, film casting, rotomolding, glueing, cutting and/or grinding.
Preferably, the total content of the natural organic fiber material, the man- made fiber material, and the matrix material in the composite product is at least 30 wt. % or at least 50 wt. %, more preferably at least 60 wt. % or at least 70 wt. % and most preferably at least 80 wt. % or at least 90 wt. % calculated from the total dry weight of the composite product.
Preferably, the total content of the natural organic fiber material in the composite product is between 20 and 99 wt. %, or between 30 and 98 wt. %, more preferably between 40 and 95 wt. %, or between 50 and 90 wt. %, or between 60 and 87 wt. %, and most preferably between 70 and 85 wt. %, or between 75 and 83 wt. % calculated from the total dry weight of the fiber materials in the composite product. Advantageously, the content of the matrix material is between 5 and 95 wt. %, or between 10 and 90 wt. %, more preferably between 15 and 85 wt. %, or between 25 and 82 wt. %, and most preferably between 30 and 80 wt. % or between 40 and 70 wt. % calculated from the total dry weight of the composite product. Advantageously, the matrix material is thermoplastic. Advantageously, the melting point of the matrix material is under 250 QC and/or the glass transition temperature of the matrix material is under 250 QC.
Advantageously, the composite product according to the present invention comprises between 10 and 80 wt. % or between 12 and 70 wt. % more preferably between 14 and 65 wt. % or between 16 and 60 wt. %, and most preferably between 18 and 55 wt. % or between 20 and 50 wt. % of organic natural fiber based material. Advantageously, the fiber length of at least 60 wt. %, more preferably at least 80 wt. %, and most preferably at least 90 wt. % of the organic natural fiber based material is between 0.1 mm and 1 .5 mm. Advantageously, at least 50 wt. %, more preferably at least 70 wt. %, and most preferably at least 90 wt. % of the organic natural fiber based material is wood based material. Advantageously, the content of the man-made fiber material is between 0.1 and 45 wt.% or between 1 and 35 wt. %, more preferably between 2 and 30 wt.%, or between 3 and 25 wt.%, and most preferably between 4 and 20 wt.% or 5 and 15 wt.% calculated from the total dry weight of the composite product. Advantageously, melting point of the man-made fiber material is at least 200QC, more preferably at least 210QC, or at least 250QC. Most preferably, the melting point and/or the glass transition temperature of the man-made fiber material is at least 20 QC greater than in the matrix material.
Advantageously, the composite product comprises between 1 and 20 wt. %, more preferably at least 2 wt. %, at least 3 wt. %, or at least 5 wt. %, and most preferably at least 7 wt. % or at least 10 wt.% glass fibers calculated from the total amount of materials in the composite product.
Advantageously the composite product comprises between 1 and 20 wt. %, more preferably at least 2 wt. %, at least 3 wt. %, or at least 5 wt. %, and most preferably at least 7 wt. % or at least 10 wt.% of plastic fibers calculated from total amount of materials in the composite product.
Advantageously, the fiber length of at least 60 wt. %, more preferably at least 80 wt. %, and most preferably at least 90 wt. % of the man-made fiber material is between 1 .5 mm and 25 mm, between 2 and 20 mm, or between 3 and 15 mm.
Advantageously, the length weighted average length of the natural organic fiber material is between 0.05 and 0.99 times, or between 0.1 and 0.95 times, or between 0.2 and 0.90 times, more preferably between 0.3 and 0.85 times, or between 0.4 and 0.90 times the length weighted average length of the man-made fiber material and/or the second fiber fraction. Advantageously, the composite product according to the present invention comprises additives and/or fillers, the total amount of said additives and fillers being between 0 and 50 wt. %, more preferably between 0.5 and 40 wt.% or between 1 and 30 wt.%, and most preferably between 3 and 25 wt.%, or between 5 and 20 wt.%.
Advantageously, the composite product that is dry absorbs moisture under 1 .5 % from the weight of the composite product in the time of 48 hours (65 % RH and 27 °-C atmosphere). Advantageously charpy notched impact of the composite product is at least 8 kJ/m2, or at least 9 kJ/m2, more preferably at least 10 kJ/m2, at least 1 1 kJ/m2, or at least 12 kJ/m2, and most preferably at least 13 kJ/m2, at least 14 kJ/m2, or at least 15 kJ/m2. Advantageously, the balance between stiffness and impact strength is controlled, for example, by the proper selection of matrix and/or fibers in the composite product.
Advantageously, the stiffness of the composite product (tensile modulus, according to ISO 527-1 /2, 1 mm/min, valid 2012) times impact properties of the composite product (notched Charpy impact strength according to ISO 179-1 /1 eA, ISO 179-2/1 eA, valid 2012) i.e. stiffness of the composite product x impact properties of the composite product, is high, which means that the material is stiff, but it is not very fragile at the same time. This may be a very important combination of the properties in many applications, because the mechanical calculations of the product are often based on the stiffness, and the stiffness of the product has to be sufficiently high. If the material is very stiff, thinner and lighter structures can be used. On the other hand, the impact strength of the material can be a problem and that is why certain stiffness and impact strength values are wanted.
Advantageously, the stiffness times the impact properties of the composite material containing the first and second fiber fractions is between 7 000 MN*kJ/m4 and 200 000 MN*kJ/m4, more preferably between 15 000 MN*kJ/m4 and 195 000 MN*kJ/m4, or between 20 000 MN*kJ/m4 and 192 000 MN*kJ/m4, and most preferably between 25 000 MN*kJ/m4 and 190 000 MN*kJ/m4.
According to one embodiment, the stiffness times the impact properties of the composite containing the first and second fiber fractions is at least 6 000 MN*kJ/m4 or at least 12 000 MN*kJ/m4, more preferably at least 25 000 MN*kJ/m4, at least 35 000 MN*kJ/m4, or at least 45 000 MN*kJ/m4, and most preferably at least 75 000 MN*kJ/m4 or at least 100000 MN*kJ/m4.
The theoretical/calculatory density (pt) of a composite material may be calculated from the masses and the densities of each individual component according to equation:
Pt = (mi + m2 + ... + mn)/( i + f- + - + Eq. (9)
Pi P2 Pn where m-i , m2, and mn are the masses of each individual component of the composite material, e.g. the composite product or the mixture containing fiber materials and the matrix material, and pi , p2, pn are the densities of each individual component of the composite material, e.g. the composite product or the mixture containing fiber material and matrix material. Advantageously, the density of the composite product is between 0.90 and 1 .8 g/cm3, or between 0.93 and 1 .6 g/cm3, more preferably between 0.95 and 1 .30 g/cm3, or between 0.97 and 1 .20 g/cm3, and most preferably between 1 .00 and 1 .15 g/cm3.
Preferably, the density of the composite product is at least 85 %, preferably over 90 %, more preferably over 95 % and most preferably over 98 % of the theoretical density. In an embodiment, the density of the composite product is at most 99.9 % of the theoretical density.
The formation of porosity into the composite product reduces the density of said product. Ideally, there is no unwanted porosity in the composite product. In practice, some porosity may exist, no matter how good the process is in regard to minimizing the formation of porosity. Therefore, the density can be used as one quantity for characterization of an organic natural fiber - thermoplastic polymer composite product. A composite product can be characterized by its theoretical/calculatory density and its experimental density. The term "pore volume" refers to a sum of partial volumes formed of gas volumes inside the object compared with the total volume of the object. In one embodiment, the pore volume of the mixture and/or the composite product is lower than 10 %, preferably lower than 5 %, more preferably lower than 2 % and most preferably lower than 1 %.
The organic natural fiber based material has the character that it absorbs water. The amount of water absorption depends on the condition around the material. Cellulose fibers absorb water quite rapidly, but when fibers are covered by hydrophobic matrix material, the absorption is much slower. The absorption rate depends on the character of the matrix material, the organic natural material content, but other things like additives can increase or decrease the absorption rate.
Advantageously, a dry composite product 40, 40a, 40b absorbs moisture less than 1 .5 %, less than 1 .0 %, or less than 0.85 %, more preferably less than 0.7 %, less than 0.6 % or less than 0.5 %, and most preferably less than 0.4 %, less than 0.3 %, less than 0.2 % or less than 0.15 % of the weight of the composite product in the time of 48 hours (65 % RH and 27 QC atmosphere).
The components for the composition may be selected to obtain a desired density and heat expansion for the composite material. Heat expansion may depend of the direction in the composite structure. In addition, the composition composite structure may have an effect on the heat expansion. For example, heat expansion in a composite structure comprising 40 w-% of organic natural fiber material may have a larger heat expansion than a composite structure comprising 50 w-% of organic natural fiber material. Therefore, the dimensional stability of a composite structure comprising 50 w-% of organic natural fiber material may be improved compared to a composite structure comprising less organic natural fiber material. The selection of the composition may therefore be used to control the speed of sound in the material.
The present invention provides an industrially applicable, simple and affordable way of making intermediate composite products 40a and final composite products 40b from the fiber materials and matrix material. The method according to the present invention can be easy and simple to realize as a production process.
The method according to the present invention is suitable for use in the manufacture of different products from different organic natural fiber based materials.
In an example embodiment, the intermediate composite product is a plate, a granulate, or a pellet. In the case of the granulate, the sizes of the granulates are preferably in the same range. The weight of one granulate is preferably between 0.01 and 0.10 g. More preferably, the weight of one granulate is between 0.015 and 0.05 g. The weights of 100 granulates is preferably between 1 and 10 g, more preferably between 1 .5 and 5 g, and most preferably between 2.0 and 4.0 g. The standard deviation in the weight of the granulate is preferably less than 15 %, more preferably less than 7 %, and most preferable less than 2 %.
Advantageously, the composite product 40 forms or is a part of
- a decking,
- a floor,
- a wall panel,
- a railing,
- a bench, for example a park bench,
- a dustbin,
- a flower box,
- a fence,
- a landscaping timber,
- a cladding,
- a siding,
- a window frame,
- a door frame,
- indoor furniture,
- a construction,
- an acoustic element,
- an instrument, or a part of an instrument,
- a part of audiovisual (AV) equipment,
- a part of public address (PA) equipment,
- a package,
- a part of an electronic device,
- an outdoor structure,
- a part of a vehicle, such as an automobile,
- a road stick for snow clearance,
- a tool,
- a toy,
- a kitchen utensil,
- cookwear,
- white goods,
- outdoor furniture,
- a traffic sign,
- sport equipment, - containers, pots, and/or dishes, and/or
- a lamp post.
Most advantageously, the composite product forms a product of electronics industry, or is a part of a product of electronics industry.
Figures 6a to 6c show some example fibers. Figures 6a and 6b show a hollow fiber with four interfaces 51 , 52, 53, 54. The fiber may be the organic natural fiber based material, or man-made fiber material. Figure 6c shows a solid fiber with two interfaces 51 , 52.
The first fiber fraction may comprise or consist of the organic natural fiber based material having a structure, where the fiber has four interfaces, i.e. first interface 51 , second interface 52, third interface 53, and fourth interface 54, when the fiber is cut in a direction perpendicular to the longest dimension of the fiber and a line 50 is drawn across the fiber in a direction perpendicular to the first interface. This kind of a structure may enable the fiber to have a large surface area, and it is possible to have good adhesion between the fibers and the matrix material.
In the case of the hollow-core fiber, the hollow-core fiber comprises a hollow in the middle of the fiber. Preferably, the thickness of all walls of the hollow- core fiber is substantially constant. In addition, the distance between the first interface and the second interface is smaller than the distance between the first interface and the third interface. In addition, the distance between the first interface and the third interface is smaller than the distance between the first interface and the fourth interface.
With the hollow-core fiber, the distance between the first interface and the second interface is preferably less than 0.5 times the distance between the first interface and the fourth interfaces. In an advantageous embodiment, in at least 50 % of fibers in the first fiber fraction the distance between the first interface and the second interface is at most 0.4 times, more preferably at most 0.3 times the distance between the first interface and the fourth interface. In this kind of a structure, the distance between the first interface and the second interface is almost independent of the direction where the line is drawn, but the distance between the first interface and the fourth interface may depend heavily on the direction of the line.
In same fiber, the distance between the first interface and the second interface can be almost 0.5 times the distance between the first interface and the fourth interface. The distance between the first interface and second interface can also be less than 0.2 times the distance between the first interface and the fourth interface. This leads to a situation where the fiber has an oval shape.
Advantageously, with the hollow core fiber, the distance between the first interface 51 and the second interface is preferably less than 60%, more preferably less than 50%, and most preferably less than 40% of the distance between the first interface 51 and the fourth interface 54. In addition, the distance between the first interface 51 and the second interface 52 preferably differs less than 30% or less than 20%, more preferably less than 10%, and most preferably less than 5% of the distance between the third interface 53 and the fourth interface 54. The distance between the first interface 51 and the fourth interface 54 may be, for example, from 2 to 12 times the distance between the first interface 51 and the second interface 52.
According to an embodiment, the second fiber fraction may comprise or consist of fiber material having a structure, where the fiber has only two interfaces 51 , 52, i.e. the first interface, and the second interface, when the fiber is cut in a direction perpendicular to the longest dimension of the fiber and a line is drawn across the fiber perpendicular to the first interface. This kind of a structure leads to a smaller surface area. In this case, the distance between the first interface and the second interface may be almost independent of the direction, which means that the cross section of the second fiber fraction is round.
EXAMPLES
The invention is described in more detail by the following examples. Example 1
Composite material containing organic natural fiber based material and man- made fiber material was prepared with a double-z-kneader as follows:
First, 395g of polypropylene and additives were added and melted in the kneader for 15min at 190°C. Then, a mixture of oven dry organic natural fiber based material and man-made fiber material comprising 275g of organic natural fiber based material in the form of kraft cellulose and 17,5g of man- made fiber material in the form of poly-paraphenylene terephtal amide (Kevlar) fibers of 2,5mm cut length were added to the polymer melt.
Mixing was continued until the compound appeared well mixed and homogenous with a good dispersion of organic natural fiber based material and man-made fiber material in the matrix material.
Example 2 Composite product containing organic natural fiber based material and man- made fiber material was formed by injection molding as follows:
Composite material containing organic natural fiber based material in pellet form, composite pellets containing man-made PET fibers of 12mm length, plastics and additives were mixed in a desired proportion before feeding into the throat of the injection molding machine and then molded into an item.
In an example case, 4180g of organic natural fiber based material containing composite pellets with 50% fiber content was mixed with 550g of composite pellets with a 20% content of man-made PET fibers of 12mm length and with 770g of virgin plastic pellets. The mixture containing organic natural fiber based material, man-made fiber material, plastics and additives was injection molded into an item with a total fiber content of 40% and man-made fiber content of 2%, with improved impact, tensile, and flexural properties in the final product. Example 3
Organic natural fiber composite containing polypropylene and soft wood based kraft cellulose (fiber content of 40 wt.-%) was mixed with long glass fiber composite (fiber content of 40 wt.-%).
The long fiber composite contained polypropylene and the length of grass fibers was 10 mm before injection molding. The length weighted length of cellulose fibers before injection molding was 1 .0 mm. Both fibers were in their own granulates and these granulates were mixed in different weight fractions in order to obtain a desired mixture of cellulose and glass fibers.
Granulate mixtures were injection moulded using melt temperatures below 200 °C. Mechanical properties are presented in the table 1 . Impact strength, modulus and tensile strength increased at the same time. It should be noted that the density increased at the same time from 1 ,07 g/cm3 to 1 ,24 g/cm3.
Table 1 . Mechanical properties of cellulose fiber and glass fiber composites and the mixture composites containing both cellulose and glass fibers. All
Figure imgf000047_0001
Example 4 One important aspect of materials for engineering purposes and technical or structural applications is the balance between stiffness and impact strength. For example, soft rubber-like material may have excellent impact strength but its stiffness may be inadequate for engineering purposes. On the other hand, a material with high stiffness may be too brittle for an application that requires good impact toughness. Therefore, materials with balanced stiffness and impact properties are desired for many applications, and this can be done e.g. by a proper selection of matrix and fibers in composite materials. Table 2. shows stiffness (tensile modulus) and impact properties (notched Charpy impact strength) for certain plastics and composites.
Table 2. Tensile modulus and Charpy notched impact strength, and values for modulus multi lied b Char notched im act stren th
Figure imgf000048_0001
In an example embodiment presented in Table 3, tensile modulus and Charpy notched impact strength and values for modulus multiplied by Charpy notched impact strength for different composite materials with different fiber content (columns 1 -4) are shown. In addition, the table 3 shows, as an example, values for modulus multiplied by Charpy notched impact strength when the Charpy notched impact strength has given values (columns 5-9).
Table 3. Tensile modulus (ISO 527-1 /2, 1 mm/min) and Charpy notched impact strength (ISO 179-1 /1 eA, ISO 179-2/1 eA), and values for modulus multiplied by Charpy notched impact strength for different composite materials with different fiber content (columns 1 -4) and values for modulus multiplied by Charpy notched impact strength when the Charpy notched impact s trength has given values (columns 5-9).
Charpy Modul Modul Modul Modul Modul Modul notche us us* us* us* us* us*
Materi Modul d *Charp Charpy Charpy Charpy Charpy Charpy al us impact y (Charp (Charp (Charp (Charp (Charp
MPa (kJ/m2) V = 8) y = 10) y = 12) y = 15) y = 20) Compo
site A,
20%
fiber
conten
t 2100 5.6 1 1760 16800 21000 25200 31500 42000
Compo
site A,
30%
fiber
conten
t 3100 6.2 19220 24800 31000 37200 46500 62000
Compo
site A,
40%
fiber
conten
t 3800 6.9 26220 30400 38000 45600 57000 76000
Compo
site A,
50%
fiber
conten 10000 t 5000 7.3 36500 40000 50000 60000 75000 0
Compo
site B,
20%
fiber
conten
t 2500 5.6 14000 20000 25000 30000 37500 50000
Compo
site B,
30%
fiber
conten 3100 6 18600 24800 31000 37200 46500 62000 t
Compo
site B,
40%
fiber
conten
t 4300 6.6 28380 34400 43000 51600 64500 86000
Compo
site C,
30%
fiber
conten
t 3100 5.8 17980 24800 31000 37200 46500 62000
Compo
site C,
40%
fiber
conten
t 4300 6.8 29240 34400 43000 51600 64500 86000
Compo
site C,
50%
fiber
conten 1 1200 t 5600 6.9 38640 44800 56000 67200 84000 0
Example 5
Fiber content in a composite product
When the organic natural fiber based material content or the man-made fiber material content of a composite, or both, are unknown, several analysis methods can be used for determination of the organic natural fiber based material content and/or the man-made fiber material content of a composite. Analysis methods suitable for determination of the organic natural fiber based material content and/or the man-made fiber material content of an unknown composite include, but are not limited to, physical, chemical, thermal, optical, and microscopy analysis techniques. The organic natural fiber based material content and/or the man-made fiber material content of an unknown composite can be analyzed, for example, with thermogravimetric, calorimetric, spectroscopic, crystallographic, tomographic, and microscopic analysis, and by selectively degrading or dissolving the different components comprising the unknown composite in order to resolve the mass fraction of the organic natural fiber based material or the man-made fiber material.
The man-made fiber material content of a polyolefin based composite containing organic natural fiber based material and man-made fiber material can be determined by selectively dissolving the polyolefin matrix e.g. in decalin and/or xylene and then separating the organic natural fiber based material and man-made fiber material by selectively dissolving or degrading either fiber material depending on the type of man-made fiber material. For example, inorganic glass fibers, as the man-made fiber material, can be separated by pyrolysis of the organic natural fiber based material after dissolving the polyolefin matrix, or by pyrolysis of the whole composite and by separating the inorganic glass fibers from the residue.
In case the man-made fiber material is an organic polymer based fiber, the organic natural fiber based material and man-made fiber material can be separated by dissolving the polyolefin matrix e.g. in decalin and/or xylene and then separating the organic natural fiber based material and man-made fiber material by selectively dissolving the organic natural fiber based material or the man-made fiber material, depending on the chemical structure of the organic polymer based man-made fiber material. For example, polyester based man-made fiber material can be dissolved in dichloromethane or methyl ethyl ketone where cellulose containing organic natural fiber based material is insoluble, thus providing means of separation of the organic natural fiber based material and man-made fiber material. In case both the man-made fiber material and the organic natural fiber based material contain cellulose, e.g. the man-made fiber is viscose, the separation between man-made fiber material and the organic natural fiber based material can be done by analysis of crystalline structure of the materials. For example, the alpha cellulose content of the man-made fiber material and the organic natural fiber based material together is measured and the proportions of man-made fiber material and the organic natural fiber based material in the sample is calculated depending on the origin of the organic natural fiber based material.
Another way of determining the content of organic natural fiber based material and man-made fiber material in a composite can be based on the quantification of the bio-based content according to standard ASTM-D6866 or with similar analysis methods that can differentiate between bio-based and non-bio-based chemical elements including, but not limited to, methods based on carbon dating. For example, in the case the man-made fiber material is from non-renewable resources, a sample extracted from a composite material containing organic natural fiber based material and man- made fiber material is analyzed for bio-based content and the organic natural fiber content is calculated according to the molar fraction of the chemical element of interest in the organic natural fiber based material.
Example 6
In one example, the final composite product contains polypropylene, hardwood cellulose and glass fibers. In this case the man-made fiber content can be measured by using pyrolysis. The temperature is selected so that more than 95 % of PP and cellulose fibers has been degraded. Test pyrolysis can be done to PP and cellulose fiber separately. The weight of the final composite product is measured before and after pyrolysis, and the man- made fiber content can be calculated from these results.
Example 7
Measurements relating to the organic fiber material The organic natural fiber content of an unknown composite can be determined, for example, by x-ray diffraction and x-ray computed tomography techniques. The organic natural fiber based material content of an unknown composite can be determined by different combinations of analysis methods including, but not limited to, the methods described above. A sample of a composite material comprising organic natural fiber based material is analyzed with x-ray computed tomography and the content of the organic natural fiber based material within the sample is determined.
Example 8
Organic natural fiber based material
Due to the hygroscopic character of organic natural fibers, the fibers typically contain moisture. The moisture content of the fibers depends, for example, on the origin of the fibers, on the storing conditions of the fibers, e.g. the relative humidity and the ambient temperature of the place where the fibers are stored, and on the processing of the fibers. Typically, the presence of moisture cannot be fully excluded while processing organic natural fibers, and in some cases excess moisture can be harmful.
In the case of organic natural fiber and thermoplastic or other polymer composites, the presence of moisture in processing can cause, for example, deterioration of product properties such as mechanical strength and visual appearance. The processing temperatures of organic natural fiber- thermoplastic/polymer composites are typically above the boiling point of water due to the higher than 100°C melting and/or the glass transition temperatures of thermoplastic/polymers.
In the processing of organic natural fiber-thermoplastic/polymer composites at temperatures above the boiling point of water, the vaporization of moisture contained in the fibers can cause formation of porosity in the product material. The porosity can appear, for example, in the form of gas bubbles or voids between fiber surfaces and matrix polymer in the composite product. Another reason for the formation of porosity can be inclusion of air or other ambient gases during the processing, due to insufficient gas removal in the process. Especially, the feeding of reinforcement fibers brings a large volume of gases to be removed from the process. For example, in the preparation of organic natural fiber - thermoplastic/polymer composites by compounding extrusion, sufficient venting is necessary in order to remove gaseous substances including water vapor, entrained air and other gases, and other volatile components.
One skilled in the art readily understands that the different embodiments of the invention may have applications in environments where optimization of the composite product is desired. It is also obvious that the present invention is not limited solely to the above-presented embodiments, but it can be modified within the scope of the appended claims.

Claims

A composite product comprising matrix material, and fiber material, the fiber material comprising a first fiber fraction and a second fiber fraction, wherein
the first fiber fraction and the second fiber fraction differ from each other chemically or dimensionally, and
the length weighted average length of the first fiber fraction is less than 0.9 times the length weighted average length of the second fiber fraction.
The composite product according to claim 1 , wherein the first fiber fraction comprises organic natural fiber based material
The composite product according to any of the preceding claims, wherein the stiffness of the composite product times the impact properties of the composite product is at least 25 000 MN*kj/m4.
The composite product according to any of the preceding claims, wherein the width of the fibers in the first fiber fraction is between 1 ,5 and 4 times the thickness of the fibers in the first fiber fraction.
The composite product according to any of the preceding claims, wherein the width of the fibers in the second fiber fraction is between 1.0 and 1.3 times the thickness of the fibers in the second fiber fraction. , The composite product according to any of the preceding claims, wherein the width of the fibers in the second fiber fraction is between 5 and 60 pm. ; The composite product according to any of the preceding claims, wherein the thickness of the fibers in the second fiber fraction is between 5 and 80 pm.
8. The composite product according to any of the preceding claims, wherein the width of the fibers in the first fiber fraction is between 15 and 50 μπι. 9. The composite product according to any of the preceding claims, wherein the thickness of the fibers in the first fiber fraction is between 5 and 18 pm.
10. The composite product according to any of the preceding claims, wherein the first fiber fraction has a length weighted average fiber length of between 0, 1 and 1 ,3 mm.
1 1. The composite product according to any of the preceding claims 1 to 8, wherein the first fiber fraction has a length weighted average fiber length of between 0.2 and 2.8 mm.
12. The composite product according to any of the preceding claims, wherein the second fiber fraction comprises polymer fibers. 13. The composite product according to any of the preceding claims, wherein the second fiber fraction comprises glass fibers.
14, The composite product according to any of the preceding claims, wherein the second fiber fraction comprises carbon fibers.
15, The composite product according to any of the preceding daims, wherein the second fiber fraction comprises viscose fibers,
16, The composite product according to any of the preceding claims, wherein the composite product is a granulate or a pellet.
17 The composite product according to any of the preceding claims 1 to 15, wherein the composite product is a plate. 18, The composite product according to any of the preceding claims 1 to 15, wherein the composite product is a product of electronics industry.
19. The composite product according to any of the preceding claims 1 to 15, wherein the composite product is a product of an instrument, or a part of an instrument
20. The composite product according to any of the preceding claims 1 to 15, wherein the composite product is a product of a part of audiovisual (AV) equipment. 21 . The composite product according to any of the preceding claims, wherein the product comprises between 1 and 20 wt. % of glass fibers, calculated from the total content of the composite product.
22. The composite product according to any of the preceding claims, wherein the product comprises between 1 and 20 wt. % of plastic fibers, calculated from the total content of the composite product.
23. The composite product according to any of the preceding claims, wherein the composite product that is dry absorbs moisture less than 1 .5 % of the weight of the composite product in the time of 48 hours
(65 % RH and 27 °C atmosphere).
24. The composite product according to any of the preceding claims, wherein the density of the composite product is between 0.90 and 1 .8 g/crn3.
25. The composite product according to any of the preceding claims, wherein the pore volume of the composite product is under 10 %. 26. The composite product according to any of the preceding claims, wherein the charpy notched impact of the composite product is at least 8 kJ/m2
27, The composite product according to any of the preceding claims, wherein the second fiber fraction has a length weighted average fiber length between 1.5 and 25 mm. The composite product according to any of the preceding claims, wherein between 20 and 99 wt, % calculated from the total amount of fiber materials in the composite product, is included in the first fiber fraction.
The composite product according to any of the preceding claims, wherein the length weighted average length of the first fiber fraction is less than 0.7 times the length weighted average length of the second fiber fraction.
30. The composite product according to any of the preceding claims, wherein the first fiber fraction comprises chemical pulp. 31. The composite product according to any of the preceding claims, wherein the second fiber fraction comprises chemical pulp.
32. The composite product according to any of the preceding claims 30 to 31 , wherein the chemical pulp consists of kraft pulp.
33. The composite product according to any of the preceding claims, wherein the lignin content of the first fiber fraction and/or the second fiber fraction is lower than 5 wt.%.
The composite product according to any of the preceding claims, wherein the first fiber fraction comprises at least 50 wt. % of virgin fibers.
The composite product according to any of the preceding claims, wherein the first fiber fraction comprises wood based material.
The composite product according to claim 35, wherein the wood material comprises softwood. The composite product according to any of the preceding claims, wherein the first fiber fraction comprises organic natural fiber based non-wood material.
The composite product according to any of the preceding claims, wherein the second fiber fraction comprises organic natural fiber based non-wood material.
39. The composite product according to claim 37 or 38. wherein the non- wood based material comprises straw, coconut, leaves, bark, seeds, hulls, flowers, vegetables or fruits from cotton, corn, wheat, oat, rye, barley, rice, flax, hemp, manila hemp, sisal hemp, jute, ramie, kenaf, bagasse, bamboo, or reed. 40, The composite product according to any of the preceding claims, wherein the first fiber fraction comprises fibers in a flake form having a width that is at least 2 times larger than the thickness of the fibers.
41. The composite product according to any of the preceding claims, wherein the matrix material is thermoplastic,
42, The composite product according to any of the preceding claims, wherein the matrix material comprises poiyoiefin. 43, The composite product according to any of the preceding claims, wherein the melting point of the matrix material is below 260 °C.
44 The composite product according to any of the preceding claims, wherein the fiber length of at least 60 wt. % of the organic natural fiber based material in the composite product is between 0.1 mm and 1 .5 mm.
The composite product according to any of the preceding claims, wherein the length of at least 80 wt. % of the organic natural fiber based material is between 0.1 mm and 1.5 mm, more preferably between 0.3 mm and 0.7 mm
RECTIFIED SHEET (Rule 48, The composite product according to any of the preceding ciaims, wherein the content of the organic natural fiber based material is between 20 and 80 dry wt. % calculated from the total dry weight of the composite product,
47, The composite product according to any of the preceding claims, wherein the content of the matrix material is between 20 and 80 dry wt. % calculated from the total dry weight of the composite product.
48, The composite product according to any of the preceding ciaims, wherein lignin content of the organic natural fiber based material is below 1 wt. %. 49, The composite product according to any of the preceding claims, wherein the content of flake-form fiber material in the composite product is at least 30 dry wt. % calculated from the total content of the organic natural fiber based material. 50. The composite product according to any of the preceding claims, wherein at least 90 wt. % of the organic natural fiber based material is wood based material.
51 , The composite product according to any of the preceding claims, wherein the organic natural fiber based material comprises at least 80 wt % of fiber materials having a length between 0.1 and 1.0 mm.
52, The composite product according to any of the preceding claims, wherein the second fiber fraction comprises man-made fiber material.
53, The composite product according to claim 52, wherein the man-made fiber material comprises mineral fibers, metal fibers, and/or man-made polymer fibers. 54, The composite product according to any of the preceding claims 52 to
53, wherein the melting point of the man-made fiber material is at least 20 °C higher than the melting point of the matrix material. 55. The composite product according to any of the preceding claims 52 to
54, wherein the man-made fiber material comprises hollow-core fibers.
56, The composite product according to any of the preceding claims 52 to
55, wherein the man-made fiber material comprises solid-core fibers.
57, The composite product according to any of the preceding claims 52 to
56, wherein the content of the man-made fiber materia! in the composite product is between 0.1 and 45 wt.%, more preferably between 1 and 20 dry wt. % calculated from the total dry weight of the composite product.
58, The composite product according to any of the preceding claims 52 to
57, wherein the composite product comprises more than one kind of man-made fiber material, and the length weighted average length of the organic natural fiber based materia! is less than 0.8 times the length weighted average length of the ail man-made fiber materials.
59, The composite product according to any of the preceding claims 52 to 58 wherein the length weighted average length of the organic natural fiber based material is less than 0.5 times the length weighted average length of the man-made fiber materials.
60.. The composite product according to any of the preceding claims 52 to
59, wherein the length of at least 80 wt. % of the man-made fiber material is between 1.5 mm and 10 mm.
61 . The composite product according to any of the preceding claims 52 to
60, wherein the length weighted average length of the man-made fiber material is between 2 mm and 5 mm.
62. A method for manufacturing a composite product comprising matrix material, and fiber material comprising a first fiber fraction and a second fiber fraction, wherein
the first fiber fraction preferably comprises organic natural fiber based material
the first fiber fraction and the second fiber fraction differ from each other chemically or dimensionaliy, and
the length weighted average length of the first fiber fraction is less than 0.9 times the length weighted average length of the second fiber fraction,
and the method comprises
adding the matrix material and the fiber materia! to the system, melting the matrix materia! at least partly and mixing the materials to form a mixture, and
- forming a composite product comprising the mixture.
63. The method according to claim 62, wherein the moisture content of the mixture 15 before the composite product is formed is less than 7% 64. The method according to claim 62 or 63, wherein the second fiber fraction comprises solid-core fibers comprising two material layers, of which at least one comprises man-made fiber material.
65, The method according to any of the preceding claims 62 to 64, wherein the fiber materia! and the matrix material are added to the system in the form of granulates and/or pellets.
66, The method according to claim 65, wherein the first fiber fraction and the second fiber fraction are added to the system in the same granulates.
67, The method according to claim 65, wherein the first fiber fraction and the second fiber fraction are added to the system in separate granulates. 51
88. The method according to any of the preceding claims 62 to 67, wherein the matrix material is thermoplastic.
69. The method according to any of the preceding claims 62 to 68, wherein the composite product is formed by injection moulding and/or extrusion.
7C The method according to claim 69, wherein the composite product is formed using an extruder in which the diameter of the extruder screw in the feeding area is between 30 mm and 550 mm.
71 , The method according to any of the preceding claims 62 to 70, wherein the temperature at which the mixture 15 is formed is lower than 220°C,
72. The method according to any of the preceding claims 62 to 71 , wherein the moisture content of the organic natural fiber based material is below 7 %, preferably below 5 during the mixing. 73. The method according to any of the preceding claims 62 to 64, wherein at least one mixer that is capable of heating the mixture is used in the mixing.
74, A system for manufacturing a composite product comprising matrix material, and fiber material comprising a first fiber fraction and a second fiber fraction,
wherein
the first fiber fraction preferably comprises organic natural fiber based material,
- the first fiber fraction and the second fiber fraction differ from each other chemically or dimensionaliy, and
the length weighted average length of the first fiber fraction is less than 0.9 times the length weighted average length of the second fiber fraction,
the system comprising
a first mixer for forming a mixture comprising said materials, means for forming a composite product comprising the mixture,
75. The system according to claim 74, wherein the first mixer and/or the means for forming the composite product comprises an extruder.
76. A composite product obtainable by the process defined in any of the method claims 62 to 73.
PCT/FI2012/051111 2012-11-14 2012-11-14 A method and a system for manufacturing a composite product and a composite product WO2014076353A1 (en)

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