Method of making a composite profile of enhanced hoop performance

Abstract

The application relates to a manufacturing method of a composite combined profile with enhanced hoop performance, which comprises the following steps: mold preparation; preparation of a pultrusion resin; calculation of the number of fiber yarns; preparation before starting; manufacturing of a pultrusion profile; bonding of the pultrusion profile; and autoclave forming. The seven steps can be used to manufacture a combined profile with a complex cross-section shape, and the processing cost is low and the operation is convenient; meanwhile, the autoclave forming step can enhance the hoop performance of the combined profile, so that the application range of the pultrusion profile is effectively expanded.

Description

Technical Field

[0001] This invention relates to the field of pultruded profile technology, and in particular to a method for manufacturing a composite profile with enhanced circumferential properties. Background Technology

[0002] Pultrusion is a molding method for producing composite linear profiles. Driven by a traction device, continuous fibers or fiber fabrics are impregnated with resin, guided in fiber distribution, and pre-formed. Then, they are extruded and cured through heated molds to obtain pultruded profiles. The advantages of pultruded profiles include excellent mechanical properties, light weight, corrosion resistance, and fatigue resistance. In industrial production, they can replace materials such as structural steel, aluminum alloys, and high-quality wood, providing a lower coefficient of thermal expansion and a lighter structural weight while ensuring sufficient strength.

[0003] Although fiber-reinforced composite pultruded products in the existing technology are lightweight and strong in the axial direction, their circumferential properties, such as stiffness, extrusion resistance and impact resistance, are relatively weak, which restricts the application of pultruded profiles. At the same time, the profiles obtained by pultrusion have simple cross-sectional shapes, making it difficult to form complex cross-sectional shapes. Summary of the Invention

[0004] To address the shortcomings of existing production technologies, the applicant provides a method for manufacturing composite profiles with enhanced circumferential performance and reasonable structure. By setting seven steps, composite profiles with complex cross-sectional shapes can be manufactured with low processing costs and convenient operation. At the same time, by setting an autoclave molding step, the circumferential performance of the composite profile can be enhanced, thereby effectively expanding the application range of pultruded profiles.

[0005] The technical solution adopted in this invention is as follows:

[0006] A method for manufacturing a composite profile with enhanced circumferential properties includes the following steps:

[0007] S1. Mold preparation: Divide the composite profile into several pultruded profiles according to the cross-sectional shape of the composite profile. Make core molds, preforming molds and forming molds according to the structure of the pultrusion equipment and individual pultruded profiles. The cross-sectional shape of the preforming mold corresponds to the cross-sectional shape of the individual pultruded profile.

[0008] S2. Pultrusion impregnation resin preparation: The matrix resin is heated in an impregnation tank until it is in a molten state to obtain pultrusion impregnation resin.

[0009] S3. Calculation of fiber yarn quantity: The fiber yarn quantity is calculated based on the cross-sectional area of ​​a single pultruded profile and the designed fiber volume content. The yarn quantity is obtained from (Equation 1):

[0010] C = [S / (A / ρ)] * B (Equation 1)

[0011] In Equation 1, C represents the number of fiber yarns.

[0012] S represents the cross-sectional area of ​​a single pultruded profile.

[0013] A represents the fiber linear density.

[0014] ρ represents the bulk density of the fiber.

[0015] B indicates the design fiber volume content;

[0016] S4. Before starting the machine, install the core mold and preforming mold onto the pultrusion equipment, thread the fiber yarn through the impregnation tank, and ensure that the fiber yarn is completely impregnated.

[0017] S5. Pultrusion profile manufacturing: The fiber yarn impregnated with pultrusion resin is melted and bonded to the surface of the mandrel through the pultrusion equipment to obtain the first profile. The pultrusion equipment scrapes off the excess fiber yarn on the surface of the first profile through the preforming mold, and then performs curing and cutting operations to obtain the pultruded profile with the corresponding cross-sectional shape.

[0018] Pultrusion equipment processes pultruded profiles with corresponding cross-sectional shapes by changing the mandrel and preforming die;

[0019] During processing, the tensile force parameters of the pultrusion equipment are set in the range of 10KN-30KN, the pultrusion speed is set in the range of 40mm / min-90mm / min, and the curing temperature is set in the range of 165℃-175℃.

[0020] S6. Pultruded profile bonding: Apply adhesive evenly to the bonding surface of the pultruded profile obtained in S5, and bond the bonding surfaces of multiple pultruded profiles together to obtain the first combined profile with the required cross-section;

[0021] S7. Autoclave molding: After the adhesive in S6. has completely cured, wrap at least one layer of reinforcing fiber prepreg cloth around the outer surface of the first composite profile to obtain the second composite profile. Place the second composite profile into the molding mold, and then place the molding mold into an autoclave for curing and molding. The molding temperature range is 90℃-125℃, and the molding time is 1h-1.5h.

[0022] Then, the molding die containing the second composite profile is removed from the autoclave, cooled, and the second composite profile is demolded to complete the production.

[0023] As a further improvement to the above technical solution:

[0024] In S2, the matrix resin is epoxy resin, unsaturated resin, or polyurethane resin.

[0025] The epoxy resin comprises bisphenol A type epoxy resin, reactive diluent, acid anhydride curing agent, and modified imidazole catalyst.

[0026] In step S4, the core mold and preforming mold are installed on the mold frame of the pultrusion equipment, and the center positions of the core mold and preforming mold are adjusted to ensure that the core mold and preforming mold are horizontally aligned.

[0027] In S6, the surface of the pultruded profile needs to be sanded before bonding.

[0028] In S6, adhesive is applied to the bonding surface of the pultruded profile using a scraper or roller.

[0029] In S6, the adhesive used is an epoxy resin adhesive.

[0030] In S6, after multiple pultruded profiles are bonded together, they are evenly clamped using C-clamps and cured at room temperature.

[0031] In S7, the reinforcing fiber prepreg is made of carbon fiber prepreg, glass fiber prepreg, or basalt fiber prepreg.

[0032] In S7, when the outer surface of the first composite profile is wrapped with multiple layers of reinforcing fiber prepreg, each layer is laid with a fiber angle of ±45 degrees.

[0033] The beneficial effects of this invention are as follows:

[0034] This invention features a compact and rational structure, and is easy to operate. By setting seven operating steps and reasonable process parameters, it can maintain the shape and precision of the profile. At the same time, it can modularly and quickly construct advanced composite beams with different cross-sectional dimensions. By bonding multiple pultruded profiles together with adhesives, it can manufacture composite profiles with complex cross-sections. The operation method is simple and adds almost no additional production costs, thus filling the gap in the difficulty of forming complex cross-section profiles from pultruded profiles.

[0035] In this invention, by setting up a hot autoclave molding step, reinforcing fiber prepreg is wrapped around the outer surface of the first composite profile to form a transverse fiber reinforced surface, and then cured and molded in a hot autoclave, thereby enabling the composite profile to obtain better circumferential properties and greatly improving its circumferential stiffness, circumferential compressive strength and circumferential impact resistance.

[0036] This invention provides a method for manufacturing composite profiles with enhanced circumferential properties. The resulting composite profiles can be used to construct large-scale precision machining equipment. While meeting the requirements of lightweight composite profiles, the method also improves their circumferential properties, thereby enabling the composite profiles to meet the requirements of various working conditions and expanding the application range of pultruded profiles. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0038] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0039] Compared to traditional structural steel, aluminum alloys and other materials, fiber-reinforced composite pultruded products are lightweight and strong in the axial direction, but their circumferential properties, such as stiffness, extrusion resistance and impact resistance, are relatively weak. Furthermore, existing pultrusion processes are difficult to form pultruded profiles with complex cross-sections.

[0040] Based on this, the present invention proposes a method for manufacturing a composite profile with enhanced circumferential properties, such as... Figure 1 As shown, a method for manufacturing a composite profile with enhanced circumferential properties includes the following steps:

[0041] S1. Mold preparation: Divide the composite profile into several pultruded profiles according to the cross-sectional shape of the composite profile. Make core molds, preforming molds and forming molds according to the structure of the pultrusion equipment and individual pultruded profiles. The cross-sectional shape of the preforming mold corresponds to the cross-sectional shape of the individual pultruded profile.

[0042] S1.1. Based on the cross-sectional shape of the composite profile, the composite profile is divided into several pultruded profiles, so that the cross-sectional shape of the individual pultruded profile is relatively simple and easy to produce by pultrusion equipment;

[0043] S2. Pultrusion wetting resin preparation: The matrix resin is heated in an impregnation tank until it is in a molten state to obtain pultrusion wetting resin;

[0044] S2.1. The matrix resin is epoxy resin, unsaturated resin, or polyurethane resin;

[0045] S2.2. The epoxy resin consists of: bisphenol A type epoxy resin, reactive diluent, acid anhydride curing agent, and modified imidazole catalyst;

[0046] S3. Calculation of fiber yarn quantity: The fiber yarn quantity is calculated based on the cross-sectional area of ​​a single pultruded profile and the designed fiber volume content. The yarn quantity is obtained from (Equation 1):

[0047] C = [S / (A / ρ)] * B (Equation 1)

[0048] In Equation 1, C represents the number of fiber yarns.

[0049] S represents the cross-sectional area of ​​a single pultruded profile.

[0050] A represents the fiber linear density.

[0051] ρ represents the bulk density of the fiber.

[0052] B indicates the design fiber volume content;

[0053] S4. Before starting the machine, install the core mold and preforming mold onto the pultrusion equipment, thread the fiber yarn through the impregnation tank, and ensure that the fiber yarn is completely impregnated.

[0054] S4.1. Install the core mold and preforming mold onto the mold frame of the pultrusion equipment, and adjust the center position of the core mold and preforming mold to ensure that the core mold and preforming mold are horizontally aligned;

[0055] S5. Pultrusion profile manufacturing: The fiber yarn impregnated with pultrusion resin is melted and bonded to the surface of the mandrel through the pultrusion equipment to obtain the first profile. The pultrusion equipment scrapes off the excess fiber yarn on the surface of the first profile through the preforming mold, and then performs curing and cutting operations to obtain the pultruded profile with the corresponding cross-sectional shape.

[0056] Pultrusion equipment processes pultruded profiles with corresponding cross-sectional shapes by changing the mandrel and preforming die;

[0057] During processing, the tensile force parameters of the pultrusion equipment are set in the range of 10KN-30KN, the pultrusion speed is set in the range of 40mm / min-90mm / min, and the curing temperature is set in the range of 165℃-175℃.

[0058] S5.1. When the pultruded profile is cured in the pultrusion equipment, a corresponding curing mold is used, and the inner surface shape of the curing mold corresponds to the outer surface shape of the pultruded profile.

[0059] S6. Pultruded profile bonding: Apply adhesive evenly to the bonding surface of the pultruded profile obtained in S5, and bond the bonding surfaces of multiple pultruded profiles together to obtain the first combined profile with the required cross-section;

[0060] S6.1. Before bonding, the surface of the pultruded profile needs to be sanded to make the surface smooth and easy to bond.

[0061] S6.2. Apply adhesive to the bonding surface of the pultruded profile using a scraper or roller;

[0062] S6.3. The adhesive used is an epoxy resin adhesive, which can achieve better interfacial strength with the pultruded profile;

[0063] S6.3. After bonding multiple pultruded profiles, use C-clamps to clamp them evenly and apply a certain pressure for room temperature curing to ensure good contact between the adhesive and the two bonding surfaces;

[0064] S7. Autoclave molding: After the adhesive in S6. has completely cured, wrap at least one layer of reinforcing fiber prepreg cloth around the outer surface of the first composite profile to obtain the second composite profile. Place the second composite profile into the molding mold, and then place the molding mold into an autoclave for curing and molding. The molding temperature range is 90℃-125℃, and the molding time is 1h-1.5h.

[0065] Then, the molding die containing the second composite profile is removed from the autoclave, cooled, and the second composite profile is demolded to complete the manufacturing process.

[0066] S7.1. The reinforcing fiber prepreg is made of carbon fiber prepreg, glass fiber prepreg, or basalt fiber prepreg. Among them, carbon fiber prepreg can provide higher circumferential strength for the second composite profile, which is convenient for subsequent application in large precision machining equipment. Basalt fiber prepreg has good corrosion resistance and chemical stability, and its high strength makes it a green and environmentally friendly material with good recycling performance, making it the preferred material for lightweight machinery.

[0067] S7.2. When the outer surface of the first composite profile is wrapped with multiple layers of reinforcing fiber prepreg, each layer is laid with a fiber angle of ±45 degrees.

[0068] This invention provides a method for manufacturing a composite profile with enhanced circumferential properties. By setting an autoclave molding step, reinforcing fiber prepreg is wrapped around the outer surface of the first composite profile and cured in an autoclave, thereby enabling the composite profile to obtain better circumferential properties. Furthermore, compared with aluminum profiles, the composite profiles made by this invention can reduce weight by 10%-20% and shorten thermal expansion change by about 70%.

[0069] The above description is an explanation of the present invention and not a limitation thereof. The scope of the present invention is defined by the claims. Within the scope of protection of the present invention, any form of modification may be made.

Claims

1. A method for manufacturing a composite profile with enhanced circumferential properties, characterized in that: Includes the following steps: S1. Mold preparation: Divide the composite profile into several pultruded profiles according to the cross-sectional shape of the composite profile. Make core molds, preforming molds and forming molds according to the structure of the pultrusion equipment and individual pultruded profiles. The cross-sectional shape of the preforming mold corresponds to the cross-sectional shape of the individual pultruded profile. S2. Pultrusion wetting resin preparation: The matrix resin is heated in an impregnation tank until it is in a molten state to obtain pultrusion wetting resin; S3. Calculation of fiber yarn quantity: The fiber yarn quantity is calculated based on the cross-sectional area of ​​a single pultruded profile and the designed fiber volume content. The yarn quantity is obtained from (Equation 1): C = [S / (A / ρ)] * B (Equation 1) In Equation 1, C represents the number of fiber yarns. S represents the cross-sectional area of ​​a single pultruded profile. A represents the fiber linear density. ρ represents the bulk density of the fiber. B indicates the design fiber volume content; S4. Before starting the machine, install the core mold and preforming mold onto the pultrusion equipment, thread the fiber yarn through the impregnation tank, and ensure that the fiber yarn is completely impregnated. S5. Pultrusion profile manufacturing: The fiber yarn impregnated with pultrusion resin is melted and bonded to the surface of the mandrel through the pultrusion equipment to obtain the first profile. The pultrusion equipment scrapes off the excess fiber yarn on the surface of the first profile through the preforming mold, and then performs curing and cutting operations to obtain the pultruded profile with the corresponding cross-sectional shape. Pultrusion equipment processes pultruded profiles with corresponding cross-sectional shapes by changing the mandrel and preforming die; During processing, the tensile force parameter of the pultrusion equipment is set at 10 kN. Within the 30KN range, the pultrusion speed is set to 40mm / min. 90 mm / min, curing temperature set at 165℃ Within the range of 175℃; S6. Pultruded profile bonding: Apply adhesive evenly to the bonding surface of the pultruded profile obtained in S5, and bond the bonding surfaces of multiple pultruded profiles together to obtain the first combined profile with the required cross-section; S7. Autoclave molding: After the adhesive in S6 has completely cured, wrap at least one layer of reinforcing fiber prepreg fabric around the outer surface of the first composite profile. When multiple layers of reinforcing fiber prepreg fabric are wrapped around the outer surface of the first composite profile, each layer is laid with a fiber angle of ±45 degrees to obtain the second composite profile. Place the second composite profile into a molding mold, and then place the molding mold into an autoclave for curing and molding at a temperature range of 90℃. 125℃, molding time is 1 hour 1.5h; Then, the molding die containing the second composite profile is removed from the autoclave, cooled, and the second composite profile is demolded to complete the production.

2. The method for manufacturing the composite profile with enhanced circumferential properties as described in claim 1, characterized in that: In S2, the matrix resin is epoxy resin, unsaturated resin, or polyurethane resin.

3. The method for manufacturing the composite profile with enhanced circumferential properties as described in claim 2, characterized in that: The epoxy resin comprises bisphenol A type epoxy resin, reactive diluent, acid anhydride curing agent, and modified imidazole catalyst.

4. The method for manufacturing the composite profile with enhanced circumferential properties as described in claim 1, characterized in that: In step S4, the core mold and preforming mold are installed on the mold frame of the pultrusion equipment, and the center positions of the core mold and preforming mold are adjusted to ensure that the core mold and preforming mold are horizontally aligned.

5. The method for manufacturing the composite profile with enhanced circumferential properties as described in claim 1, characterized in that: In step S6, the surface of the pultruded profile needs to be sanded before bonding.

6. The method for manufacturing the composite profile with enhanced circumferential properties as described in claim 1, characterized in that: In S6, adhesive is applied to the bonding surface of the pultruded profile using a scraper or roller.

7. The method for manufacturing the composite profile with enhanced circumferential properties as described in claim 1, characterized in that: In S6, the adhesive used is an epoxy resin adhesive.

8. The method for manufacturing the composite profile with enhanced circumferential properties as described in claim 1, characterized in that: In S6, after multiple pultruded profiles are bonded together, they are evenly clamped using C-clamps and cured at room temperature.

9. The method for manufacturing the composite profile with enhanced circumferential properties as described in claim 1, characterized in that: In S7, the reinforcing fiber prepreg is made of carbon fiber prepreg, glass fiber prepreg, or basalt fiber prepreg.

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