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EP-4735245-A1 - SEMIPREG WITH MATRIX COATING

EP4735245A1EP 4735245 A1EP4735245 A1EP 4735245A1EP-4735245-A1

Abstract

The invention relates to a semipreg made of UD layers, wherein one or both outer layers of the semipreg has/have 30 to 45 wt.% of matrix material, based on the total weight of the semipreg. At least 60 wt.% of the matrix material (based on the total weight of the semipreg) penetrates less than 100 µm of the semipreg (measured in the thickness direction of the semipreg). The invention additionally relates to a method for producing the semipreg and to a method for producing a fiber-reinforced composite component made of the semipreg.

Inventors

  • KRABBE, JUTTA
  • GOTTHARDT, Daria

Assignees

  • Teijin Carbon Europe GmbH

Dates

Publication Date
20260506
Application Date
20240529

Claims (15)

  1. 1. Semi-prepreg (1) comprising at least two unidirectional fiber layers (3) made of carbon fibers, wherein the carbon fibers within each of the unidirectional fiber layers (3) are provided parallel next to one another and adjacent to one another and the carbon fibers of adjacent unidirectional fiber layers (3) are laid at an angle between 0 and 180° to one another, wherein the semi-prepreg (1) comprises 30 to 45% by weight of matrix material (2) based on the total weight of the semi-prepreg (1), wherein one of the at least two unidirectional fiber layers (3) forms a first outer layer of the semi-prepreg (1) and a first surface of this fiber layer is a first outer surface of the semi-prepreg (1), wherein the at least one other unidirectional fiber layer forms a second outer layer of the semi-prepreg (1) and a second surface of this fiber layer is a second outer surface of the semi-prepreg (1), wherein the first surface and the first outer surface is approximately parallel to the second surface and the second outer surface, wherein the at least two unidirectional fiber layers (3) made of carbon fibers are sewn together perpendicular to the main propagation direction of the carbon fibers of the unidirectional fiber layers (3), characterized in that the entire matrix material (2) is provided on the first and/or the second outer surface, wherein at least 60 wt.% of the entire Matrix material (2) penetrates from this or these outer surface(s) less than 100 pm perpendicular to the main propagation direction of the carbon fibers of the unidirectional fiber layers (3) into the semi-prepreg (1).
  2. 2. Semi-prepreg (1) according to claim 1, wherein 90 wt.% of the total matrix material (2) penetrates into the semi-prepreg (1) starting from this or these outer surface(s) of the semi-prepreg (1) less than 20 pm, preferably less than 10 pm, perpendicular to the main propagation direction of the carbon fibers of the unidirectional fiber layers (3).
  3. 3. Semi-prepreg (1) according to claim 1 or 2, wherein the matrix material (2) is distributed on the outer surface(s) continuously and/or discontinuously.
  4. 4. Semi-prepreg (1) according to at least one of the preceding claims, wherein the amount of matrix material (2) on the first outer surface is equal to the amount of matrix material on the second outer surface or the amount of matrix material (2) on the first outer surface is not equal to the amount of matrix material (2) on the second outer surface.
  5. 5. Semi-prepreg (1) according to at least one of the preceding claims, wherein the matrix material (2) is a thermoplastic, a thermoset or a mixture thereof.
  6. 6. Semi-prepreg (1) according to at least one of the preceding claims, wherein the semi-prepreg (1) has further unidirectional fiber layers (3) and/or fleece layers between the outer layers.
  7. 7. Semi-prepreg (1) according to at least one of the preceding claims, wherein the carbon fibers of the at least two fiber layers (3) undulation-free in the fiber layers (3).
  8. 8. Semi-prepreg (1) according to at least one of the preceding claims, wherein the at least two fiber layers (3) are laid at an angle of 0790°, +457135°, 20760°, 307150° or in a combination of said angles to one another within the semi-prepreg (1).
  9. 9. A method for producing a semi-prepreg (1) according to at least one of claims 1 to 8, wherein the matrix material (2) is applied to the first and/or the second outer surface by powder impregnation, powder coating, padding, doctor blade and/or film transfer.
  10. 10. The method according to claim 9, wherein firstly the at least two unidirectional fiber layers (3) made of carbon fibers are laid down at an angle other than 0° to each other and then the matrix material (2) is applied.
  11. 11. A method according to claim 10, wherein before applying the matrix material (2) the at least two fiber layers (3) are sewn together perpendicular to the main propagation direction of the carbon fibers of the unidirectional fiber layers (3).
  12. 12. The method according to claim 10, wherein firstly the matrix material (2) is applied to a first and/or a second of the at least two fiber layers (3) and then the at least two fiber layers (3) are arranged to form the semi-prepreg (1) such that the matrix material (2) is present as the outer surface of the semi-prepreg (1).
  13. 13. Manufacturing process for a fiber-reinforced composite material, comprising at least one semi-prepreg (1) according to at least one of the Claims 1 to 8, wherein the at least one semi-prepreg (1) becomes the fiber-reinforced composite material under pressure and heat without the addition of a further matrix material.
  14. 14. Manufacturing method according to claim 13, wherein when using more than two semi-prepregs (1), these are arranged in the structure for the production of the composite material such that the matrix material lies on the outer surfaces of the composite material to be finished.
  15. 15. Manufacturing process according to claim 13, wherein for the production of the a single semi-prepreg (1 ) is used for the production of the composite material. a. Manufacturing method according to claim 14, wherein the semi-prepreg (1) has more than two fiber layers (3) and/or nonwoven material.

Description

semi-prepreg with matrix coating Description: The invention relates to a semi-prepreg with at least two unidirectional fiber layers and a matrix coating according to the preamble of claim 1. Unidirectional fiber layers (UD layers) are well known. UD layers are also well known, which are impregnated with a matrix material to form a prepreg. In a prepreg, the matrix material is usually located within the fiber material. Preferably, the matrix material is evenly distributed in the fiber material in a prepreg, so the matrix material is found everywhere in the fiber material in approximately the same proportion. The document US 2009/0068428 describes a type of fabric with an adhesive layer on at least one side. A majority of the fabric layers are connected to one another by the adhesive layer. The fabric has reinforcing fibers in one direction and auxiliary threads woven into them. The adhesive content on at least one surface of the fabric should not be more than 40 g/m 2 and the material thus created is then impregnated with a matrix material. The document DE 10 2011 084 626 discloses a fiber-reinforced composite material that is intended to be used as a clutch disc. The composite material has at least two superimposed fiber layers made of carbon fibers, whereby the layers should be impregnated with matrix. The document US 2012/0100354 describes a fiber-reinforced material that is to be formed from NCFs and contains carbon fibers. The material is to be later processed with a matrix material and the NCF layers are to be sewn together. The document EP 3 705215 describes a process for impregnating textiles to form a prepreg, where the textile can be a UD material, for example. In the process, the process parameters - such as the contact pressure - can be adapted to the different fabrics and the different matrix materials used, so that optimal impregnation or full impregnation can be achieved. The impregnation can be carried out on one side or both sides. The disadvantage of the known materials is that matrix material usually has to be added to the material if a component (for example a fiber-reinforced composite component) is to be made from it. If the material already has the corresponding content of matrix material (in the form of a prepreg), the matrix material is integrated within the fiber layer and the material is usually difficult to drape as a prepreg. The document US 2022/0388274 also describes the use of fiber layers, for example in the form of fleece or in the form of UD fiber layers. A matrix layer is provided on one side in direct contact with the fiber layers, which is intended to connect the fiber layers lying on top of each other. The matrix layer is intended to achieve the connection of the two fiber layers by impregnating the two fiber layers. Consequently, the matrix material must the matrix layer penetrates into both fiber layers and (based on the arrangement of the matrix layer) completely penetrates at least the adjacent fiber layer in order to be able to penetrate at least partially into the more distant fiber layer. According to the document, the material can contain 20 to 50 wt.% matrix material. The Japanese document JP 2018065999 proposes a reinforcing fiber material that can also have a matrix material. The reinforcing fibers can be present in a fiber aggregate, whereby a sewn UD structure is also taught here. According to Figure 1, a matrix material is provided on one side of the fiber aggregate. The matrix material should preferably remain on the surface of the fiber aggregate to the extent of 50 to 70% by weight. Depending on the selected shape of the fiber aggregate and the selected matrix material, the matrix material should not impregnate more than 15 to 97 pm into the fiber aggregate. The matrix material content should be between 1 and 20% by weight and improve the dimensional stability and the impregnatability of the material. A disadvantage of this state of the art is that a corresponding amount of matrix material still has to be added in the component manufacturing process. The aim of the present idea was therefore to provide a semi-prepreg that already has the necessary matrix content for component production, but which should still be easy to drap. This problem is solved by a semi-prepreg with the features of claim 1. According to claim 1, the semi-prepreg has at least two fiber layers, each fiber layer being a so-called UD fiber layer (and thus not a fabric). In a UD fiber layer, the fibers within the fiber layer lie parallel to one another and against one another (without gaps). The at least two fiber layers form the outer layers of the semi-prepreg, so that each fiber layer has an outer side. The at least two fiber layers can be placed on top of one another in such a way that the fiber orientation of both fiber layers is essentially parallel to one another or the fiber orientations of the different fiber layers are at an angle other than 0° to one another. Furthermore,