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EP-4741571-A2 - COMPOSITE AND STRUCTURE, METHODS FOR MANUFACTURING THE SAME AND USES THEREOF

EP4741571A2EP 4741571 A2EP4741571 A2EP 4741571A2EP-4741571-A2

Abstract

Described herein is composite structure comprising microfibrillated cellulose (MFC) monofilament permeated by a hydrophobic resin. Also described herein are a structure and methods of manufacturing the composite material and structure and the uses thereof.

Inventors

  • SALMELA, JUHA

Assignees

  • Spinnova Oyj

Dates

Publication Date
20260513
Application Date
20230224

Claims (15)

  1. A composite comprising continuous fibrous monofilaments as reinforcing material and an unsaturated polyester (UP) resin, wherein the composite is obtained by impregnating the reinforcing material with the unsaturated polyester resin using a pultrusion method.
  2. The composite of claim 1, wherein the continuous fibrous monofilaments comprise non regenerated microfibrillated cellulose (MFC).
  3. The composite of any of the preceding claims, wherein the monofilaments comprise at least 50 wt. % non-regenerated MFC.
  4. The composite of any of the preceding claims, wherein the monofilaments comprise 80-98 wt. % non-regenerated MFC and 2-20 wt. % of a dispersing agent, optionally wherein the dispersing agent includes carboxymethyl cellulose (CMC).
  5. The composite of any of the preceding claims, wherein a majority of the monofilaments have cross sectional dimensions selected from 30-300 × 10 -6 m / 5-30 × 10 -6 m, 30-200 × 10 -6 m / 5-20 × 10 -6 m, or 30-120 × 10 -6 m / 5-10 × 10 -6 m.
  6. The composite of any of the preceding claims, wherein the composite is in the form of a layer, sheet, or tube.
  7. A method for manufacturing a composite, comprising: - providing continuous fibrous monofilament as reinforcing material; and - impregnating the reinforcing material with unsaturated polyester (UP) resin by a pultrusion method.
  8. The method of claim 7, wherein the continuous fibrous monofilaments comprise non regenerated microfibrillated cellulose (MFC).
  9. The method of claim 7 or 8, wherein the monofilaments comprise at least 50 wt. % non-regenerated MFC.
  10. The method of any of claim 7 to 9, wherein the monofilaments comprise 80-98 wt. % non-regenerated MFC and 2-20 wt. % of a dispersing agent, optionally wherein the dispersing agent includes carboxymethyl cellulose (CMC).
  11. The method of any of claim 7 to 10, wherein a majority of the monofilaments have cross sectional dimensions selected from 30-300 × 10 -6 m / 5-30 × 10 -6 m, 30-200 × 10 -6 m / 5-20 × 10 -6 m, or 30-120 × 10 -6 m / 5-10 × 10 -6 m.
  12. The method of any of claims 7 to 11, further comprising producing the monofilaments by extruding an aqueous suspension comprising 4-10 wt.% dry matter including non-regenerated microfibrillated cellulose (MFC), a dispersing agent, at least one of the following: a natural wax, a thermoplast, a sizing agent, or natural rubber as a water-based emulsion or dispersion, and a crosslinking agent, from which dry matter at least 50 wt.% is non-regenerated MFC, and 90-96 wt.% water, and drying the extruded monofilament.
  13. The method of any of claim 7 to 12, further comprising curing the impregnated monofilaments to form the composite.
  14. The method of any of claim 7 to 13, wherein curing is carried out at a temperature of 70-130 °C.
  15. The method of any of claim 7 to 14, wherein the composite is formed into a layer, sheet or tubular product.

Description

Technical field The present invention relates to a method of manufacturing composites and structures. Further, the invention relates to composites and structures obtainable by said methods, as well as uses of said composites and structures. Background There exists a variety of different fiber-based reinforcements for a polymer matrix in composite materials. In such reinforcements, fibers of glass, carbon, aramid or basalt have traditionally been used. In recent years, the application of recyclable natural cellulosic fibers such as long fibers of hemp, flax, kanaf, cotton, jute, sisal and coconut and shorter plant fibers, mainly derived from wood pulp, has also received increasing attention due to increasing environmental consciousness. The type of the reinforcement fiber is one of the most contributory factors impacting on performance of the composite material. For instance, carbon fiber reinforcements are commonly used in the composites wherever high strength-to-weight ratio and stiffness are required. One drawback of carbon fiber material is its environmental impact; it is notoriously difficult to recycle, energy-intensive to produce and it does not biodegrade, for instance. In recent years, microfibrillated cellulose (MFC) has been gaining more and more attention as a reinforcement material due to MFC's potentiality to provide high strength-to-weight ratio reinforcement for composites in environmentally friendly manner. However, there are various challenges related to the known solutions that utilize MFC in the context of composite materials. For instance, high volume fraction of the cellulose microfibrils within the polymer matrix that is necessary to produce a stiff and strength composite, remains challenging and energy-intensive to achieve. Consequently, there exists a demand for improved MFC reinforced composites and laminate structures, and simple methods for manufacturing said composites and laminate structures. Summary The aim of the present invention is to at least alleviate one or more of the above drawbacks or challenges associated with the existing solutions of MFC reinforced composites and laminate structures and relating manufacturing methods. The aims of the invention are obtained with composites and structures, methods for manufacturing said composite and structure, and uses thereof, which are characterized in what is presented in the independent claims. Some advantageous embodiments of the invention are presented in the dependent claims. Detailed description According to an aspect the invention there is provided a composite comprising one or more of microfibrillated cellulose (MFC) monofilaments, yarns made up of such monofilaments, a nonwoven fabric made up of such monofilaments and fabric made up of yarn comprising MFC fibers in form of monofilaments being permeated by a hydrophobic resin. According to a one embodiment of the present invention there is provided a composite comprising a fabric (i.e., a cloth) made up of yarn comprising microfibrillated cellulose (MFC) fibers. The fabric being permeated by a hydrophobic resin encapsulating at least one of two opposing surfaces of the fabric. The yarns of the fabric may comprise spun cellulose monofilaments having an elongate internal structure comprising interlocked MFC fibers. This embodiment can be combined with the other embodiments here described. Terms "permeate(d)" and "impregnate(d)" are used here interchangeably, both meaning that the resin penetrates into (and through) the reinforcing material. Said reinforcing material may comprise monofilaments of microfibrillated non-regenerated cellulose as such or formed into a yarn or fabric and optionally other fibrous material including man-made cellulosic materials. The term "monofilament" as used herein refers to a continuous length of individual microfibrillated cellulose fibrils grouped and extending generally along the longitudinal dimension of the cellulose monofilament. The fibrils interact chemically and/or mechanically in order to form a permanent monofilament structure (in other words, fibrils of the monofilament are interlocked). The monofilament cannot be opened or disassembled. Disintegration of fibrous monofilament yields only individual fibrils. The fibrous monofilament may comprise continuous length of several meters or kilometers. Individual fibrils of the fibrous monofilament are mainly oriented along length of the fibrous monofilament. A monofilament as used here is a single strand filament produced by extruding and then drying a suspension. The monofilament as used in this context comprises at least 50 wt.-% of non-regenerated microfibrillar cellulose (MFC), a dispersing agent, such as CMC, and optionally strength additives, hydrophobic adhesives, sizing agents, crosslinking agents, pigment(s), and/or other modifier(s). In one embodiment the monofilament comprises 80 to 98 wt.-% non-regenerated microfibrillated cellulose (MFC); 2 to 20 wt.-% dispersion agent(s), such a