FIELD OF THE INVENTION

The present application relates to a fiber reinforced composition and the use thereof. Further, the present application relates a method for producing a fiber reinforced composition.

BACKGROUND

A composite refers to a material consisting of two or more individual constituents. A reinforcing constituent is embedded in a matrix to form the composite. Common composites are composed of glass or carbon fiber in a plastic resin. However, disposal of e.g. glass fiber after its use in different applications is challenging. Recycling the glass fiber reinforced composite material may also not be an alternative. One alternative is to burn the glass fiber reinforced composite after its use. However, burning glass fiber may adversely affect the apparatuses used for the burning process. Another alternative is that the glass fiber is simply being disposed to a landfill. However, this is not a beneficial alternative from an environmental perspective. Thus, as the reuse or disposal of the glass fiber after its use in end products has such challenges, it may be foreseen that the use thereof e.g. as a reinforcing constituent material may be prohibited in the future by legislation.

The inventors have, however, recognized the need for a fiber reinforced composition, the reuse or disposal would not have an adverse impact on the environment or on the equipment used for the recycling process . PURPOSE

The purpose is to provide a new type of a fiber reinforced composition and the use thereof. Further, the purpose is to provide a method for producing a fiber reinforced composition.

SUMMARY

The fiber reinforced composition according to the present application is characterized by what is presented in claim 1.

The method for producing for producing a fiber reinforced composition according to the present application is characterized by what is presented in claim 7.

The use of the fiber reinforced composition according to the present application is characterized by what is presented in claim 16.

DETAILED DESCRIPTION

The present application relates to a fiber reinforced composition comprising a reinforcing constituent of fibers embedded in a polymer matrix, wherein the fibers are fibers of cellulose carbamate, hemicellulose carbamate, or their combination, and wherein the fiber reinforced composition comprises 5 - 98 weight-% of the reinforcing constituent of fibers based on the total weight of the fiber reinforced composition .

The present application relates to a fiber reinforced composition comprising a reinforcing constituent of fibers embedded in a polymer matrix, wherein cellulose carbamate, hemicellulose carbamate, or their combination has been used in the preparation of the fibers, and wherein the fiber reinforced composition comprises 5 - 98 weight-% of the reinforcing constituent of fibers based on the total weight of the fiber reinforced composition.

The present application further relates to a method for producing a fiber reinforced composition comprising a reinforcing constituent of fibers embedded in a polymer matrix, wherein the method comprises :

subjecting cellulose, hemicellulose, or their combination, to a carbamation process for substituting at least one hydroxyl group on the cellulose and/or hemicellulose backbone with at least one carbamate group to produce cellulose carbamate, hemicellulose carbamate, or their combination.

The present application further relates to the use of the fiber reinforced composition as defined in the current application for the production of an aircraft, a boat, an automotive, a bath, a tank, a container, a sport or leisure product such as a surf board, a fishing rod, a ski and golf shaft, or a toy, an electronic or an electrical application such as a printed circuit board or an insulation, a housing of an electronic device, a covering or a casing such as a casing of a laptop or a mouse, a television, a loudspeaker, an audio device, a roofing, a windmill blade, a pipe, a tube, a cable cover, a cladding, a cast, or a door. In one embodiment, a fiber reinforced composite is used as the fiber reinforced composition.

The inventors surprisingly found out that fibers of cellulose carbamate and/or hemicellulose carbamate exhibit properties that enable their efficient use in fiber reinforced composites for different applications. Subjecting the cellulose and/or hemicellulose to a carbamation process for producing cellulose carbamate ester and/or hemicellulose carbamate ester results in the formed esters being able to withstand e.g. the high temperatures often used during the production of end products of the fiber reinforced composition.

In one embodiment, when providing or preparing the fibers for the fiber reinforced composition, cellulose carbamate, hemicellulose carbamate, or their combination is used. In one embodiment, the fibers are prepared from cellulose carbamate, hemicellulose carbamate, or their combination. In one embodiment, the fibers are fibers comprising or consisting of cellulose carbamate, hemicellulose carbamate, or their combination. In one embodiment, the fibers are fibers comprising or consisting of cellulose carbamate. In one embodiment, the fibers are fibers comprising or consisting of hemicellulose carbamate. In one embodiment, the fibers are fibers comprising or consisting of a combination of cellulose carbamate and hemicellulose carbamate.

In this specification, unless otherwise stated, the expression "carbamation process" should be understood as a process during which at least one carbamate group is introduced in the cellulose backbone and/or the hemicellulose backbone, respectively. During the carbamation process hydroxyl groups on the backbone part are modified such that the protons therein are substituted so as to form carbamate groups .

In one embodiment, two or more hydroxyl groups on the backbone part are converted into carbamate groups. In one embodiment, the method comprises subjecting cellulose, hemicellulose, or their combination, to a carbamation process for substituting hydroxyl groups on the cellulose and/or hemicellulose backbone with carbamate groups to produce cellulose carbamate, hemicellulose carbamate, or their combination. The cellulose backbone, or its main chain, is formed of glucose units linked to each other. These glucose units may be functionalized.

The carbamation process can be carried out by any suitable method for producing cellulose carbamate and/or hemicellulose carbamate. One alternative is disclosed in WO 2015/198218.

In one embodiment, the carbamation process is carried out by allowing urea to react with cellulose and/or hemicellulose. In the below scheme, the reaction between urea and cellulose is presented:

In one embodiment, the carbamation process is carried out at a temperature of 100 - 170 °C, or 120 - 160 °C, or 130 - 150 °C, or e.g. at 140 °C . In one embodiment, a catalyst is used in the carbamation process. In one embodiment, the catalyst is a metal salt, e.g. zinc sulphate. In one embodiment, urea decomposes to ammonia and isocyanic acid in elevated temperatures and isocyanic acid reacts with the hydroxyl groups of cellulose forming cellulose carbamate. The higher temperature may decrease the time needed for urea to decompose to ammonia and isocyanic acid.

In one embodiment, the carbamation process is continued until a degree of substitution of the cellulose carbamate and/or the hemicellulose carbamate of 0.1 - 1.5, or 0.2 - 1 , or 0.4 - 0.7, is achieved. In one embodiment, the degree of substitution of the cellulose carbamate and/or the hemicellulose carbamate is 0.1 - 1.5, or 0.2 - 1, or 0.4 - 0.7.

In this specification, unless otherwise stated, the expression "degree of substitution" (DS) should be understood as the average number of substituted hydroxyl groups per sugar unit. In one embodiment, the degree of substitution indicates the average number of substituted hydroxyl groups in an anhydroglucose unit. In general, the expression "anhydroglucose unit" (AGU) refers to a single sugar molecule in a polymer. Typically, the hydroxyl groups of cellulose and hemicellulose react in the order of 06 > 02 > 03.

In one embodiment, the fiber reinforced composition comprises 5 - 50 weight-%, or 10 - 40 weight-%, or 20 - 30 weight-% of the reinforcing constituent of fibers based on the total weight of the fiber reinforced composition. When the fiber reinforced composition comprises 5 - 50 weight-%, or 10 - 40 weight-%, or 20 - 30 weight-% of the reinforcing constituent of fibers based on the total weight of the fiber reinforced composition it may be directly used for the production of an end product. It may e.g. be subjected to a formation or molding process to provide the final shape of the end product.

In one embodiment, the fiber reinforced composition comprises 50 - 98 weight-%, or 60 - 95 weight-%, or 70 - 90 weight-% of the reinforcing constituent of fibers based on the total weight of the fiber reinforced composition. When the fiber reinforced composition comprises 50 - 98 weight-%, or 60 - 95 weight-%, or 70 - 90 weight-% of the reinforcing constituent of fibers based on the total weight of the fiber reinforced composition, the manufacturer of the end product, for the production of which the fiber reinforced composition is used, may select a desired further polymer matrix and the adjust the properties of the end product in a desired manner.

The amount of fibers in the fiber reinforced composition can be measured e.g. in the following manner: The sample material is dried in oven in 70 (102) °C for 24 hours. 0.5 1 g of the sample material is weighed into 80 ml of solvent (e.g. dekahydronaphtalene (CioHis) ) and left over night. Then the solution is boiled for several hours (7-8 h) . After boiling the mixture is filtered out. The material remaining on filter paper is dried in oven in 70 (102) °C for 24 hours and cooled in desiccator. The remaining material is weighed and the fiber amount is calculated .

In one embodiment, the fiber reinforced composition is in the form of at least one granulate, or in the form of a fiber reinforced concentrate, or in the form of a fiber reinforced composite.

In one embodiment, the fiber reinforced composition is in the form of at least one granulate, or in the form of a fiber reinforced concentrate, or in the form of a fiber reinforced composite. The at least one granulate or the fiber reinforced concentrate may contain a lesser amount of polymer matrix compared to the amount of polymer matrix present in the fiber reinforced composite.

In one embodiment, the fibers are man-made fibers. In this specification, unless otherwise stated, the expression "man-made" fibers should be understood as fibers whose chemical composition, structure, and/or properties are modified by a human being during the manufacturing process thereof. I.e. the one producing the man-made fibers is able to at least partly determine the properties, such as the strength, of the produced fibers. Man-made fibers are to be distinguished from natural, biologically produced fibers. In one embodiment, the man-made fibers are provided with a spinning apparatus.

In one embodiment, the cellulose and/or hemicellulose are/is obtained from a plant. In one embodiment, the cellulose and/or hemicellulose are/is obtained wood, straw, hemp, flax, kenaf, or any combination thereof. In one embodiment, the cellulose and/or hemicellulose are/is obtained from wood. In one embodiment, the cellulose and/or hemicellulose are/is obtained from softwood and/or hardwood. In one embodiment, the cellulose and/or hemicellulose are/is obtained from a Kraft process. The Kraft process, which is also known as kraft pulping or sulfate process, is a process for conversion of wood into wood pulp. In one embodiment, the cellulose is cellulose from dissolving pulp, bleached kraft pulp, or any combination thereof.

In one embodiment, the method comprises providing fibers from the produced cellulose carbamate, hemicellulose carbamate, or their combination .

In one embodiment, the method comprises providing fibers of cellulose, hemicellulose, or their combination, before subjecting to the carbamation process .

In one embodiment, the step of providing fibers comprises providing at least one filament fiber and/or staple fiber.

In one embodiment, the step of providing fibers comprises providing man-made fibers.

In one embodiment, the method comprises washing the produced cellulose carbamate, hemicellulose carbamate, or their combination. In one embodiment, the washing is carried out with a washing fluid. In one embodiment, the washing fluid is selected from a group consisting of a solvent. In on embodiment, the solvent is water, an alcohol, or any combination thereof. In one embodiment, the alcohol is selected from a group consisting of methanol, ethanol, and any combination thereof. In one embodiment, the washing fluid comprises auxiliary substances. The washing may be carried out to remove possible impurities as well as reacted and unreacted materials such as dissolving components.

In one embodiment, the method comprises allowing the produced cellulose carbamate, hemicellulose carbamate, or their combination to dry.

In one embodiment, the step of providing fibers comprises providing the fibers by an extrusion process or by a spinning process. In one embodiment, the extrusion process is a blow extrusion process. In one embodiment, the spinning process is a wet spinning process, a dry spinning process, a dry jet-wet spinning process, a gel spinning process, or a melt spinning process. In one embodiment, the fibers are provided by a wet spinning process. A fiber strength that is suitable for many end products can be obtained by the use of wet spinning.

The form of the fibers may vary depending on e.g. its end use. The fibers can have any desired or predetermined form or shape. In one embodiment, the fibers are hollow or solid. In one embodiment, the cross-section of the fibers are essentially circular, quadratic, or has any other predetermined form.

In one embodiment, the fibers have an average fiber length of 0.01 - 60 mm, or 0.1 - 55 mm, or 2 - 50 mm. The length of the fibers, such as cellulose fibers, can depend on e.g. wood species, growing conditions, the delignification or pulping process and/or the following beating process that the fibers have been subjected to. In one embodiment, the fibers are subjected to fractionation, beating, refining, kneading, cutting and/or retting in order to have a desired average fiber length. In this specification, unless otherwise stated, the expression "average length" or "average fiber length" should be understood as the length-weighted average fiber length. In one embodiment, the fibers have an average fiber width of 10 - 20 ym. The fiber length as well as the fiber width can be determined e.g. according to standard ISO 16065-2:2014 by using a FS5 fiber analyzer or e.g. by using image analysis. In one embodiment, the ratio of the average fiber length to the average fiber width of the fibers is above 500, or above 1000.

In one embodiment, the method comprises combining the fibers with a polymer matrix. In one embodiment, the fibers are combined with the polymer matrix by using extrusion, molding, lamination, pultrusion, impregnation, a pre-preg process, winding, or any combination thereof.

In one embodiment, the composition formed by combining the fibers with the polymer matrix is allowed to cure. In one embodiment, the composition formed by combining the fibers with the polymer matrix is heated, e.g. at a temperature of 20 - 200 °C, or at a temperature of 40 - 180 °C, for curing the composition. In one embodiment, the heating is carried out for 0.5 - 24 hours.

In one embodiment, the reinforcing constituent of fibers is in the form of a mat or sheet. The fiber mat or fiber sheet may be embedded within the polymer matrix. In one embodiment, the thickness of the fiber mat or fiber sheet is below 2 cm, or below 1 cm, or below 800 ym, or below 300 ym, or below 100 ym. The fibers can be oriented or non- oriented in the mat.

In one embodiment, the fibers are mixed into the polymer matrix. In one embodiment, the fibers are mixed into the polymer matrix to form an isotropic mixture . In one embodiment, the polymer matrix comprises or consists of a thermoplastic polymer. In one embodiment, the polymer matrix comprises or consists of polyethylene, polypropylene, polyethylene terephthalate, polystyrene, or any other suitable thermoplastic polymer.

In one embodiment, the polymer matrix comprises or consists of a resin, or a thermoset resin, or an epoxy resin. Epoxy resins are low molecular weight pre-polymers or higher molecular weight polymers which normally contain at least two epoxide groups. Epoxy resins are polymeric or semi polymeric materials. Epoxy resins can be produced industrially. The raw materials for epoxy resin production are usually petroleum derived, although plant derived sources are also commercially available, e.g. plant derived glycerol is used to make epichlorhydrin . Difunctional and multifunctional epoxy resins such as diglycidyl ether of bisphenol A (DGEBPA) , triglycidyl p-amino phenol (TGAP) , tetraglycidylether of 4 , 4 ' -diaminodiphenyl methane (TGGDDM) , and epoxy novolacs can be mentioned as examples of epoxy resins that can be used. In one embodiment, the epoxy resin is a hot curing epoxy resin. In one embodiment, the epoxy resin is a cold curing epoxy resin. In one embodiment, the polymer matrix comprises or consists of bio-monoethylene glycol (bMEG) , bio-monopropylene glycol (bMPG) , or any combination thereof.

It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments. The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages.

The embodiments described hereinbefore may be used in any combination with each other. Several of the embodiments may be combined together to form a further embodiment. A fiber reinforced composition, a method, or a use, to which the application is related, may comprise at least one of the embodiments described hereinbefore .

The reinforcing constituent of fibers has the added utility of being based on cellulose and/or hemicellulose, both of which originate from a natural source such as wood. In other words, most part of the reinforcing constituent of fibers used in the fiber reinforced composition is based on a natural, non synthetic, material. Thus, the fiber reinforced composition has the added utility of being easier to burn after its use in end products than the fiber reinforced compositions that traditionally use e.g. glass fiber as the reinforcing constituent.

Further, the use of man-made fibers has the added utility of being thermally stable.

The fibers of cellulose carbamate, hemicellulose carbamate, or their combination, have the added utility of exhibiting properties making them suitable for use as the reinforcing constituent in a fiber reinforced composition with a polymer matrix. The fibers prepared by using cellulose carbamate, hemicellulose carbamate, or their combination, has the added utility of being heat resistant.

EXAMPLES

Reference will now be made in detail to the described embodiments.

The description below discloses some embodiments in such a detail that a person skilled in the art is able to utilize the fiber reinforced composition and the method based on the disclosure. Not all steps of the embodiments are discussed in detail, as many of the steps will be obvious for the person skilled in the art based on this specification. EXAMPLE 1 - Producing a fiber reinforced composition

In this example a fiber reinforced composition was prepared. Firstly, cellulose carbamate was produced by a carbamation process as below described .

The carbamation process was started by selecting the source of cellulose. Three different cellulose sources were used, i.e. dissolving pulp, Kraft birch, or Kraft conifer.

Then the cellulose was pretreated either by subjecting it to a sodium hydroxide treatment or to a hydrothermal treatment (HT) for chemical activation. The hydrothermal treatment was conducted in the presence of water at a temperature of 170 °C . Then the cellulose was washed.

Thereafter, the pretreated cellulose was allowed to react with urea at a temperature of above 130 °C . The reaction was carried out in an organic solvent (xylene or toluene) . The reaction was continued until a desired predetermined degree of substitution was achieved.

The different tested conditions and materials are indicated in the below table:

* 100 % indicates that the cellulose was completely dry and 30 % means that 70 % of water was present.

After the carbamation process the cellulose carbamate was dissolved in cold NaOH and thereafter subjected to a spinning process under the influence of H ₂ SO ₄ to produce fibers therefrom.

The produced fibers were then mixed into polypropylene for embedding said fibers therein by the use of a molding process.

From tests performed on the produced fiber reinforced composition, it was noted that produced fiber reinforced composition had properties suitable for use in further applications.

It is obvious to a person skilled in the art that with the advancement of technology, the basic idea may be implemented in various ways. The embodiments are thus not limited to the examples described above; instead they may vary within the scope of the claims.

The embodiments described hereinbefore may be used in any combination with each other. Several of the embodiments may be combined together to form a further embodiment. A composition, a method, or a use, disclosed herein, may comprise at least one of the embodiments described hereinbefore. It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments. The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages. It will further be understood that reference to 'an' item refers to one or more of those items. The term "comprising" is used in this specification to mean including the feature (s) or act(s) followed thereafter, without excluding the presence of one or more additional features or acts.