Fiber reinforced composite material and preparation method thereof

Abstract

The invention relates to the technical field of fiber reinforced composite material preparation, in particular to a fiber reinforced composite material and a preparation method thereof. The preparation method of the fiber reinforced composite material comprises the following steps: laying a polyolefin material layer and a fiber reinforced material layer, and carrying out hot pressing and cold pressing to obtain the fiber reinforced composite material, when the melt index ratio of the contact surfaces of the polyolefin material layer and the fiber reinforced material layer is 0.3-3, directly laying the polyolefin material layer and the fiber reinforced material layer; when the melt index ratio between the contact surfaces of the polyolefin material layer and the fiber reinforced material layer is smaller than 0.3 or larger than 3, a connecting material layer is laid between the contact surfaces of the polyolefin material layer and the fiber reinforced material layer; and the melt index ratio between the joining material layer and the contact surface of the polyolefin material layer and the joining material layer and the contact surface of the fiber reinforced material layer is 0.3-3. The preparation method is simple, convenient, high in flexibility, high in compatibility and high in efficiency, does not use an adhesive, and is green and environment-friendly.

Description

Technical Field

[0001] The invention relates to the technical field of fiber reinforced composite material preparation, and in particular to a fiber reinforced composite material and a preparation method thereof. Background Art

[0002] Polyolefin materials are light and low in density. For example, self-reinforced polyolefin materials are widely used in various fields such as sports and leisure products, automotive interior and exterior decoration, such as suitcase shells, automotive underbody panels, etc. However, the strength of self-reinforced polyolefin materials is relatively low. In order to improve their strength and broaden the application scenarios, it is often necessary to compound self-reinforced polyolefin materials with other materials to obtain self-reinforced polyolefin composite materials with high strength and retaining other excellent properties. In the prior art, the method of improving the performance of self-reinforced polyolefin materials is mostly to add carbon fillers such as graphene, or other inorganic fillers, to them during preparation, which is costly and the preparation process is cumbersome. If an attempt is made to directly hot-press and compound a plurality of formed polymer materials to obtain a composite material with the properties of a plurality of polymer materials, there will be a phenomenon of mutual repulsion during the movement of the macromolecules between them, and they may be temporarily compounded together, but then automatically delaminated, or they cannot be compounded together at all, and the resulting material cannot be used. If it is to be compounded and used, it needs to be bonded by an adhesive, but the use of the adhesive will first bring about greater environmental problems, and secondly, the performance of the adhesive itself may also affect the composite material. Summary of the invention

[0003] Therefore, the purpose of the present invention is to provide a fiber-reinforced composite material and a preparation method thereof, which is convenient and quick to compound a formed polyolefin material and other formed fiber-reinforced materials by a hot pressing molding method. The obtained fiber-reinforced composite material has the performance advantages of both polyolefin materials and fiber-reinforced materials and can be used in a wide range of fields.

[0004] To this end, the present invention provides the following technical solutions:

[0005] The invention provides a method for preparing a fiber reinforced composite material, comprising the following steps: laying a polyolefin material layer and a fiber reinforced material layer, performing hot pressing, and performing cold pressing to obtain the fiber reinforced composite material; when the ratio of the melt index between the contact surfaces of the polyolefin material layer and the fiber reinforced material layer is 0.3-3, directly laying the polyolefin material layer and the fiber reinforced material layer; when the ratio of the melt index between the contact surfaces of the polyolefin material layer and the fiber reinforced material layer is less than 0.3 or greater than 3, laying a connecting material layer between the contact surfaces of the polyolefin material layer and the fiber reinforced material layer; the ratio of the melt index between the contact surfaces of the connecting material layer and the polyolefin material layer is 0.3-3; the ratio of the melt index between the contact surfaces of the connecting material layer and the fiber reinforced material layer is 0.3-3.

[0006] Optionally, the fiber reinforced material includes a thermosetting fiber reinforced material and / or a thermoplastic fiber reinforced material; Optionally, the matrix in the thermosetting fiber reinforced material includes at least one of phenolic resin, amino resin, unsaturated polyester resin, and epoxy resin; Optionally, the matrix in the thermoplastic fiber reinforced material includes at least one of polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), and polyamide (PA). In the present invention, it is not limited to the selection of fibers in the fiber reinforced material, nor is it limited to the length of the fibers. Typically, the fibers in the fiber reinforced material can be organic fibers, such as aramid fibers, polyester fibers, polyimide fibers, etc.; natural fibers, such as cotton fibers, hemp fibers, etc.; inorganic fibers, such as glass fibers, carbon fibers, boron fibers, etc.; the fiber reinforced material can be at least one of short fiber reinforced thermoplastic composite materials (fiber length 38 to 150 mm), long fiber reinforced thermoplastic composite materials (fiber length ≥ 300 m), and continuous fiber reinforced thermoplastic composite materials (theoretically, the fiber length is infinitely extended).

[0007] Optionally, the connection material includes a resin film; optionally, the resin film includes at least one of a polyolefin film, a polyurethane film, a polyethylene-polyvinyl acetate copolymer film, a polyamide film, and a polyethersulfone film.

[0008] Optionally, the polyolefin material includes at least one of a polypropylene material, a polyethylene material, a poly-1-butene material, and a poly-4-methyl-1-pentene material.

[0009] Optionally, the polypropylene material includes a layer of homopolypropylene and two layers of copolymer polypropylene composited on its upper and lower surfaces; wherein the copolymer polypropylene is used to provide toughness and the homopolypropylene is used to provide strength; further optionally, the thickness ratio of the homopolypropylene and the copolymer polypropylene is 2 to 6:1, such as 4:1, 5:1, 6:1, 5:2, 7:2, etc., which can be selected according to the requirements for material properties; further optionally, the relative molecular weight of the copolymer polypropylene is 50,000 to 100,000, and the melt index is 10 to 20 g / 10 min, and the relative molecular weight of the homopolypropylene is 200,000 to 500,000, and the melt index is 2 to 8 g / 10 min; further optionally, the melt index of the copolymer polypropylene is 15 g / 10 min, and the melt index of the homopolypropylene is 6 g / 10 min.

[0010] Optionally, the hot pressing temperature is 100-230° C., the pressure is 0.1-5 MPa, and the time is 0.5-30 min; preferably, the hot pressing temperature is 140° C., the pressure is 2 MPa, and the time is 20 min.

[0011] Optionally, the cold pressing temperature is 10-70°C, the pressure is 0.1-5MPa, and the time is 5-30min; preferably, the cold pressing temperature is 40°C, the pressure is 2MPa, and the time is 5min.

[0012] Optionally, before cold pressing, the method further includes cooling the material after hot pressing to 10 to 70°C.

[0013] Optionally, the number of the polyolefin material layers is 1 to 100; preferably, the number of the polyolefin material layers is 1 to 10.

[0014] Optionally, the number of the fiber-reinforced material layers is 1 to 100; preferably, the number of the fiber-reinforced material layers is 1 to 10.

[0015] Optionally, the polyolefin material layer has a thickness of 0.1 to 2 mm and a density of 0.83 to 0.96 g / cm 3 , the strength is 10~200MPa.

[0016] Optionally, the fiber-reinforced material layer has a thickness of 0.1 to 3 mm and a density of 1.42 to 3 g / cm 3 , the strength is 200~4000MPa.

[0017] Optionally, the thickness of the connecting material layer is 0.01-0.2 mm.

[0018] In the preparation method of the fiber-reinforced composite material provided by the present invention, it is not limited to overlapping the polyolefin material layer and the fiber-reinforced material layer layer by layer. When laying, multiple polyolefin material layers can be adjacent to each other, or multiple fiber-reinforced material layers can be adjacent to each other. Preferably, when the number of laid layers is greater than 2, the polyolefin material layer and the fiber-reinforced material layer in the overall fiber-reinforced composite material are laid axially symmetrically with the most central laid layer as the central axis; in this way, the overall performance of the obtained fiber-reinforced composite material is more balanced.

[0019] The present invention also provides a fiber-reinforced composite material prepared by the preparation method.

[0020] The technical solution of the present invention has the following advantages:

[0021] The preparation method of the fiber reinforced composite material provided by the present invention comprises the following steps: laying a polyolefin material layer and a fiber reinforced material layer, performing hot pressing, and performing cold pressing to obtain a fiber reinforced composite material; when the ratio of the melt index between the contact surface of the polyolefin material layer and the fiber reinforced material layer is 0.3-3, directly laying the polyolefin material layer and the fiber reinforced material layer; when the ratio of the melt index between the contact surface of the polyolefin material layer and the fiber reinforced material layer is less than 0.3 or greater than 3, laying a connecting material layer between the contact surface of the polyolefin material layer and the fiber reinforced material layer; the ratio of the melt index between the contact surface of the connecting material layer and the polyolefin material layer is 0.3-3; the ratio of the melt index between the contact surface of the connecting material layer and the fiber reinforced material layer is 0.3-3. The preparation method is simple and flexible, has strong compatibility, and has high molding efficiency, and can achieve an efficiency of 15min / piece. Only by hot pressing and cold pressing, the polyolefin material and the fiber reinforced material can be combined at will to obtain a fiber reinforced composite material whose density and strength meet the required working conditions; and no adhesive is used in the preparation, which is green and environmentally friendly. Laying a connecting material layer between the polyolefin material layer and the fiber-reinforced material layer allows the macromolecular chains to dissolve or mix at the interface between the two phases after hot pressing and cold pressing between the adjacent material layers, thereby ensuring close adhesion between the layers; using the ratio of the melt indexes between the two to determine whether a connecting material layer needs to be laid is a reasonable way to save materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 This is a photo of the fiber-reinforced composite material obtained in Example 1 of the present invention;

[0024] Figure 2 This is a photo of the fiber-reinforced composite material obtained in Example 2 of the present invention;

[0025] Figure 3 This is a photo of the fiber-reinforced composite material obtained in Example 3 of the present invention;

[0026] Figure 4 This is a photo of the fiber-reinforced composite material obtained in Example 4 of the present invention;

[0027] Figure 5 This is a photo of the fiber-reinforced composite material obtained in Example 5 of the present invention;

[0028] Figure 6 This is a photo of the fiber-reinforced composite material obtained in Example 6 of the present invention;

[0029] Figure 7 This is a photo of the fiber-reinforced composite material obtained in Example 7 of the present invention;

[0030] Figure 8 This is a photo of the fiber-reinforced composite material obtained in Comparative Example 1 of the present invention;

[0031] Fig. 9 This is a photo of the fiber-reinforced composite material obtained in Comparative Example 2 of the present invention;

[0032] Fig.10 This is a photograph of the fiber-reinforced composite material obtained in Comparative Example 3 of the present invention. DETAILED DESCRIPTION

[0033] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Experimental Materials

[0035] Polypropylene sheet (SRPP) used as polyolefin material①: density 0.92g / cm 3 , strength 180MPa, a core layer with a thickness of 0.1mm and a surface layer with a thickness of 0.025mm compounded on its upper and lower surfaces; the core layer is homopolymer polypropylene with a relative molecular weight of 300000 and a melt index of 6g / 10min; the surface layer is copolymer polypropylene with a relative molecular weight of 70000 and a melt index of 15g / 10min.

[0036] Fiber reinforced sheet (FRTP) used as fiber reinforced material①: density 1.65g / cm 3 , strength 3000MPa, thickness 0.25mm, matrix is ​​polypropylene thermoplastic resin, melt index is 2.5g / 10min, the selected fiber is 3K carbon fiber, which is a long fiber, density: 1.96g / cm 3 , strength 3000MPa.

[0037] Resin film (FILM) ① used as a connecting material: thermoplastic polypropylene resin film, thickness 0.05 mm, melt index 6 g / 10 min.

[0038] All experimental materials are sheets with a length × width of 85 × 55 (mm).

[0039] Example 1

[0040] This embodiment provides a fiber-reinforced composite material and a preparation method thereof, comprising the following steps:

[0041] (1) Lay 1 layer of SRPP①, 1 layer of FILM①, and 1 layer of FRTP① in the mold.

[0042] (2) Place in a hot press, press at 140°C, 2 MPa for 20 min, take out, and transfer to a cold press.

[0043] (3) Place it in a cold press, press it for 5 min at 40°C and 2 MPa, and take it out to obtain a fiber-reinforced composite material. The total preparation time is only 25 min. Take a photo of it directly after taking it out. Figure 1 As shown; from left to right are photos of one surface, another surface, and the side.

[0044] Example 2

[0045] This embodiment provides a fiber-reinforced composite material and a preparation method thereof, comprising the following steps:

[0046] (1) Lay 1 layer of FRTP①, 1 layer of FILM①, 1 layer of SRPP①, 1 layer of FILM①, 1 layer of FRTP①, 1 layer of FILM①, 1 layer of SRPP①, 1 layer of FILM①, and 1 layer of FRTP① in the mold.

[0047] (2) Place in a hot press, press at 140°C, 1.5 MPa for 20 min, take out, and transfer to a cold press.

[0048] (3) Place it in a cold press, press it at 45°C and 1.5 MPa for 10 min, take it out, and obtain a fiber-reinforced composite material. The total preparation time is only 30 min. Take a photo of it directly after taking it out. Figure 2 As shown; from left to right are photos of one surface, another surface, and the side.

[0049] Example 3

[0050] This embodiment provides a fiber-reinforced composite material and a preparation method thereof, comprising the following steps:

[0051] (1) Lay 1 layer of FRTP①, 1 layer of FILM①, 2 layers of SRPP①, 1 layer of FILM①, 1 layer of FRTP①, 1 layer of FILM①, 2 layers of SRPP①, 1 layer of FILM①, and 1 layer of FRTP① in the mold.

[0052] (2) Place in a hot press, press at 145°C, 2 MPa for 20 min, take out, and transfer to a cold press.

[0053] (3) Place it in a cold press, press it at 40°C and 2MPa for 8 minutes, take it out, and obtain a fiber-reinforced composite material. The total preparation time is only 28 minutes. Take a photo of it directly after taking it out. Figure 3 As shown; from left to right are photos of one surface, another surface, and the side.

[0054] Example 4

[0055] This embodiment provides a fiber-reinforced composite material and a preparation method thereof, comprising the following steps:

[0056] (1) Lay 1 layer of FRTP①, 1 layer of FILM①, 4 layers of SRPP①, 1 layer of FILM①, and 1 layer of FRTP① in the mold.

[0057] (2) Place in a hot press, press at 138°C, 2.3 MPa for 15 min, take out, and transfer to a cold press.

[0058] (3) Place it in a cold press, press it for 5 min at 40°C and 2.3 MPa, and take it out to obtain a fiber-reinforced composite material. The total preparation time is only 20 min. Take a photo of it directly after taking it out. Figure 4 As shown; from left to right are photos of one surface, another surface, and the side.

[0059] Example 5

[0060] This embodiment provides a fiber-reinforced composite material and a preparation method thereof, comprising the following steps:

[0061] (1) Lay 1 layer of FILM①, 2 layers of FRTP①, 1 layer of FILM①, 2 layers of SRPP①, 1 layer of FILM①, 2 layers of FRTP①, and 1 layer of FILM① in the mold.

[0062] (2) Place in a hot press, place in a hot press, press at 135°C, 2.5 MPa for 20 min, take out, and transfer to a cold press.

[0063] (3) Place it in a cold press, press it at 30°C and 2.5 MPa for 15 min, take it out, and obtain a fiber-reinforced composite material. The total preparation time is only 35 min. Take a photo of it directly after taking it out. Figure 5 As shown; from left to right are photos of one surface, another surface, and the side.

[0064] Example 6

[0065] This embodiment provides a fiber-reinforced composite material and a preparation method thereof, comprising the following steps:

[0066] (1) Lay 1 layer of SRPP①, 1 layer of FILM①, 2 layers of FRTP①, 1 layer of FILM①, and 1 layer of SRPP① in the mold.

[0067] (2) Place in a hot press, press at 136°C, 1.2 MPa for 18 min, take out, and transfer to a cold press.

[0068] (3) Place it in a cold press, press it for 16 min at 36°C and 1.2 MPa, and take it out to obtain a fiber-reinforced composite material. The total preparation time is only 34 min. Take a photo of it directly after taking it out. Figure 6 As shown; from left to right are photos of one surface, another surface, and the side.

[0069] Example 7

[0070] This embodiment provides a fiber-reinforced composite material and a preparation method thereof, comprising the following steps:

[0071] (1) Lay 1 layer of SRPP①, 1 layer of FILM①, 4 layers of FRTP①, 1 layer of FILM①, and 1 layer of SRPP① in the mold.

[0072] (2) Place in a hot press, press at 144°C, 3.1 MPa for 20 min, take out, and transfer to a cold press.

[0073] (3) Place it in a cold press, press it for 25 min at 27°C and 3.1 MPa, and take it out to obtain a fiber-reinforced composite material. The total preparation time is only 45 min. Take a photo of it directly after taking it out. Figure 7 As shown; from left to right are photos of one surface, another surface, and the side.

[0074] Comparative Example 1

[0075] This comparative example provides a multilayer composite material and a preparation method thereof, comprising the following steps:

[0076] (1) Lay 8 layers of SRPP① in the mold.

[0077] (2) Place in a hot press, press at 143°C, 4.5 MPa for 10 min, take out, and transfer to a cold press.

[0078] (3) Place the composite material in a cold press machine and press it for 10 min at 28°C and 4.5 MPa. Take it out to obtain a multilayer composite material. Figure 8 As shown; from left to right are photos of one surface, another surface, and the side.

[0079] Comparative Example 2

[0080] This comparative example provides a multilayer composite material and a preparation method thereof, comprising the following steps:

[0081] (1) Lay 4 layers of FRTP① in the mold.

[0082] (2) Place in a hot press, press at 140°C, 0.8 MPa for 25 min, take out, and transfer to a cold press.

[0083] (3) Place in a cold press, press at 33°C, 0.8 MPa for 15 min, take out, and obtain a multilayer composite material. Take a photo of it directly after taking it out. Fig. 9 As shown; from left to right are photos of one surface, another surface, and the side.

[0084] Comparative Example 3

[0085] This comparative example provides a multilayer composite material and a preparation method thereof, comprising the following steps:

[0086] (1) Lay one layer of SRPP① and two layers of FRTP① in the mold.

[0087] (2) Place in a hot press, press at 142°C, 1.5 MPa for 20 min, take out, and transfer to a cold press.

[0088] (3) Place the composite material in a cold press machine and press it for 18 min at 36°C and 1.5 MPa. Take it out to obtain a multilayer composite material. Fig.10 As shown; from left to right are photos of one surface, the side, and another surface.

[0089] Test Example 1

[0090] All the final products obtained in the examples and comparative examples were tested for maximum deflection, maximum bending force, bending strength and elastic modulus according to GB / T 1449-2005 fiber reinforced plastic bending performance test method. Three parallel pieces of each sample were taken and tested three times. The results are shown in Table 1. Among them, due to the delamination of comparative example 3, only the thickness could be barely tested, and the mechanical properties could not be tested. The plate obtained in example 1 was too soft and could not be tested.

[0091] Table 1

[0092]

[0093]

[0094]

[0095] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for preparing a fiber-reinforced composite material, characterized in that: The steps include: Laying a polyolefin material layer and a fiber-reinforced material layer, performing hot pressing, and performing cold pressing to obtain a fiber-reinforced composite material; When the ratio of the melt index between the contact surfaces of the polyolefin material layer and the fiber reinforcement material layer is 0.3 to 3, the polyolefin material layer and the fiber reinforcement material layer are directly laid; When the ratio of the melt index between the contact surfaces of the polyolefin material layer and the fiber-reinforced material layer is less than 0.3 or greater than 3, a connecting material layer is laid between the contact surfaces of the polyolefin material layer and the fiber-reinforced material layer; The ratio of the melt index between the contact surface of the connecting material layer and the polyolefin material layer is 0.3 to 3; The ratio of the melting index between the contact surfaces of the connecting material layer and the fiber-reinforced material layer is 0.3-3.

2. The preparation method according to claim 1, characterized in that: The fiber reinforced material includes thermosetting fiber reinforced material and / or thermoplastic fiber reinforced material; optionally, the matrix in the thermosetting fiber reinforced material includes at least one of phenolic resin, amino resin, unsaturated polyester resin, and epoxy resin; optionally, the matrix in the thermoplastic fiber reinforced material includes at least one of polyethylene, polypropylene, polyvinyl chloride, polystyrene, and polyamide.

3. The preparation method according to claim 1 or 2, characterized in that: The connecting material includes a resin film; optionally, the resin film includes at least one of a polyolefin film, a polyurethane film, a polyethylene-polyvinyl acetate copolymer film, a polyamide film, and a polyethersulfone film.

4. The preparation method according to any one of claims 1 to 3, characterized in that: The polyolefin material includes at least one of a polypropylene material, a polyethylene material, a poly-1-butene material, and a poly-4-methyl-1-pentene material; optionally, the polypropylene material includes a layer of homopolypropylene and two layers of copolymer polypropylene composited on its upper and lower surfaces; further optionally, the thickness ratio of the homopolypropylene to the copolymer polypropylene is 2 to 6:1; further optionally, the relative molecular weight of the copolymer polypropylene is 50,000 to 100,000, and the melt index is 10 to 20 g / 10 min, and the relative molecular weight of the homopolypropylene is 200,000 to 500,000, and the melt index is 2 to 8 g / 10 min; further optionally, the melt index of the copolymer polypropylene is 15 g / 10 min, and the melt index of the homopolypropylene is 6 g / 10 min.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The hot pressing temperature is 100-230° C., the pressure is 0.1-5 MPa, and the time is 0.5-30 min; optionally, the hot pressing temperature is 140° C., the pressure is 2 MPa, and the time is 20 min.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The cold pressing process may be performed at a temperature of 10 to 70° C., a pressure of 0.1 to 5 MPa, and a time of 5 to 30 min. Optionally, the cold pressing process may be performed at a temperature of 40° C., a pressure of 2 MPa, and a time of 5 min.

7. The preparation method according to any one of claims 1 to 6, characterized in that: Before cold pressing, the method further includes cooling the material after hot pressing to 10 to 70°C.

8. The preparation method according to any one of claims 1 to 7, characterized in that: The number of layers of the polyolefin material layer is 1 to 100; optionally, the number of layers of the polyolefin material layer is 1 to 10; And / or, the number of the fiber-reinforced material layers is 1 to 100; optionally, the number of the fiber-reinforced material layers is 1 to 10.

9. The preparation method according to any one of claims 1 to 8, characterized in that: The thickness of the polyolefin material layer is 0.1-2 mm, and the density is 0.83-0.96 g / cm 3 , strength is 10~200MPa; And / or, the thickness of the fiber-reinforced material layer is 0.1-3 mm, and the density is 1.42-3 g / cm 3 , strength is 200~4000MPa; And / or, the thickness of the connecting material layer is 0.01-0.2 mm.

10. A fiber-reinforced composite material obtained by the preparation method according to any one of claims 1 to 9.

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