A method for preparing continuous bamboo fiber composite door and window frame

Abstract

The present invention provides a method for preparing a continuous bamboo fiber composite door and window frame, and relates to the technical field of composite materials. The method for preparing a continuous bamboo fiber composite door and window frame provided by the present invention comprises the following steps: under external force traction, thermosetting bamboo fiber prepreg is sequentially preformed and cured to obtain a continuous bamboo fiber composite door and window frame. The present invention utilizes the characteristics of low cost and high tensile strength of bamboo fiber, uses thermosetting bamboo fiber prepreg as raw material, and prepares a continuous bamboo fiber composite door and window frame through a pultrusion molding process, which provides new raw materials for door and window frames, and also provides a new development direction for the application of high value-added and high-end products of bamboo fiber.

Description

Technical Field

[0001] The invention relates to the technical field of composite materials, and in particular to a method for preparing a continuous bamboo fiber composite door and window frame. Background Art

[0002] Doors and windows are important components of building envelope structures. They are the main channels for energy exchange between the inside and outside of buildings, and are also the weakest link in the energy barrier between indoor and outdoor areas of a house. The energy lost through doors and windows accounts for about 20% of the total social energy consumption. It can be seen that the key to building energy conservation is door and window energy conservation. Reducing the energy consumption of doors and windows plays an important role in achieving the goal of energy conservation and emission reduction.

[0003] Existing door and window frames include plastic steel door and window frames, aluminum alloy door and window frames, composite door and window frames and wooden door and window frames. Among them, plastic steel door and window frames have quickly occupied the market due to their unique thermal insulation performance and cost advantages compared with aluminum door and window frames, but plastic steel door and window frames are prone to deformation and leakage, and have poor aging resistance. Aluminum alloy door and window frames have poor thermal insulation and heat insulation performance due to the good thermal conductivity of metal. Composite door and window frames mainly include fiberglass door and window frames, composite wood door and window frames, aluminum-wood composite door and window frames, aluminum-plastic composite door and window frames, wood-plastic composite door and window frames, etc. Among them, aluminum-wood composite door and window are widely promoted and applied. This kind of door and window combines the thermal insulation and decorative effects of wood and the advantages of high surface hardness of aluminum alloy. It is made of wood and aluminum alloy (generally thermal insulation type) profiles connected by mechanical means. Due to the relatively high price, this kind of door and window is mainly used in some high-end villa projects. The application of wooden door and window frames has a history of many years and was once the most important door and window material. Due to the natural low thermal conductivity of wood, the thermal insulation performance of wooden doors and windows is very superior. However, with the reduction of forest resources and the increasing attention paid by humans to protecting the environment and ecological balance, the market capacity and supply of wooden door and window frames have been limited. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a continuous bamboo fiber composite door and window frame. The continuous bamboo fiber composite door and window frame prepared by the present invention has the advantages of light weight and high strength, low carbon and environmental protection, good thermal insulation performance, good durability, good processing performance and designable structure, and can extend the service life of the door and window frame.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing a continuous bamboo fiber composite door and window frame, comprising the following steps:

[0007] Under external force traction, the thermosetting bamboo fiber prepreg is preformed and cured in sequence to obtain a continuous bamboo fiber composite door and window frame.

[0008] Preferably, the traction speed of the external force traction is 100-350 mm / min.

[0009] Preferably, the preforming temperature is 50-350° C.; the preforming time is 10-120 min; and the preforming pressure is 1-100N.

[0010] Preferably, the curing temperature is 100-250° C.; the curing time is 30-120 min; and the curing pressure is 1-20 MPa.

[0011] Preferably, the method for preparing the thermosetting bamboo fiber prepreg comprises the following steps:

[0012] The continuous bamboo fiber substrate is placed in a thermosetting resin compound system and roller impregnated to obtain a resin-impregnated bamboo fiber system;

[0013] The resin-impregnated bamboo fiber system is subjected to heat-pressing pretreatment, and after the obtained system is shaped, it is coated to obtain a thermosetting bamboo fiber prepreg.

[0014] Preferably, the continuous bamboo fiber substrate includes bamboo strips, bamboo fiber yarn or bamboo fiber felt.

[0015] Preferably, the initial temperature of the thermosetting resin compound system is 10-60° C. lower than the curing temperature of the thermosetting resin compound system itself.

[0016] Preferably, the pre-tension of the roller dipping is 1 to 50 N, and the roller spacing is 1 to 100 mm.

[0017] Preferably, the temperature of the hot pressing pretreatment is 90-120° C., the pressure is 0.01-5 MPa, and the time is 1-60 min.

[0018] Preferably, the thermosetting bamboo fiber prepreg is in a gel state.

[0019] The present invention provides a method for preparing a continuous bamboo fiber composite door and window frame, comprising the following steps: preforming and curing a thermosetting bamboo fiber prepreg in sequence under external force traction to obtain a continuous bamboo fiber composite door and window frame. The present invention utilizes the characteristics of low cost and high tensile strength of bamboo fiber, uses thermosetting bamboo fiber prepreg as raw material, and prepares a continuous bamboo fiber composite door and window frame through a pultrusion molding process, which provides new raw materials for door and window frames, and also provides a new development direction for the application of high value-added and high-end products of bamboo fiber.

[0020] The continuous bamboo fiber composite door and window frame prepared by the present invention is light and high-strength, and is more convenient in assembly, transportation and storage; it is environmentally friendly and healthy, has excellent moisture-proof and anti-corrosion properties, and has a good development prospect; the continuous bamboo fiber composite door and window frame has the same processing properties as logs, can be nailed, sawed, heat-insulated, has a smooth surface, is economical and practical, and has an elegant appearance; the continuous bamboo fiber composite door and window frame does not crack, expand, or deform, has low water absorption, has good mechanical properties, good durability, is easy to clean, has a long service life, and saves later repair and maintenance costs.

[0021] The results of the embodiments show that the continuous bamboo fiber composite door and window frames prepared by the present invention have a tensile strength of 40 to 1200 MPa, a bending strength of 40 to 1200 MPa, and a thermal conductivity of 0 to 0.5 W / (m·K). BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A model diagram of a continuous bamboo fiber composite door and window frame prepared in the embodiment;

[0023] Figure 2 This is a schematic diagram of the continuous bamboo fiber composite door and window frame prepared in Example 1. DETAILED DESCRIPTION

[0024] The present invention provides a method for preparing a continuous bamboo fiber composite door and window frame, comprising the following steps:

[0025] Under external force traction, the thermosetting bamboo fiber prepreg is preformed and cured in sequence to obtain a continuous bamboo fiber composite door and window frame.

[0026] In the present invention, the traction speed of the external force is preferably 100-350 mm / min, more preferably 150-250 mm / min; the intensity of the external force traction is preferably 50-60N.

[0027] In the present invention, the preforming temperature is preferably 50-350°C, more preferably 80-140°C; the preforming time is preferably 10-120min, more preferably 30-60min; the preforming pressure is preferably 1-100N, more preferably 10-50N.

[0028] In the present invention, the curing temperature is preferably 100-250°C, more preferably 120-150°C; the curing time is preferably 30-120 min, more preferably 60-90 min; the curing pressure is preferably 1-20 MPa, more preferably 5-10 MPa.

[0029] The present invention adopts the above-mentioned process parameters, and can shorten the curing cycle, improve production efficiency and reduce production costs on the basis of ensuring the quality of the continuous bamboo fiber composite material door and window frame.

[0030] In the present invention, after the curing, the obtained product is preferably cut to length or post-processed under continuous demolding to obtain a continuous bamboo fiber composite material door and window frame.

[0031] In the present invention, the tensile strength of the prepared continuous bamboo fiber composite door and window frame is preferably 40 to 1200 MPa, more preferably 395 to 480 MPa; the flexural strength is preferably 40 to 1200 MPa, more preferably 400 to 500 MPa; the thermal conductivity is preferably 0 to 0.5 W / (m·K), more preferably 0.16 to 0.21 W / (m·K).

[0032] In the present invention, the resin content of the thermosetting bamboo fiber prepreg is preferably 5 to 45 wt %. In the present invention, the preparation method of the thermosetting bamboo fiber prepreg preferably comprises the following steps:

[0033] The continuous bamboo fiber substrate is placed in a thermosetting resin compound system and roller impregnated to obtain a resin-impregnated bamboo fiber system;

[0034] The resin-impregnated bamboo fiber system is subjected to heat-pressing pretreatment, and after the obtained system is shaped, it is coated to obtain a thermosetting bamboo fiber prepreg.

[0035] The present invention preferably places a continuous bamboo fiber substrate in a thermosetting resin compound system, performs roller impregnation, and obtains a dipped bamboo fiber system. In the present invention, the continuous bamboo fiber substrate preferably includes bamboo strips, bamboo fiber yarns or bamboo fiber felts, and more preferably bamboo strips. In the present invention, bamboo strips have the characteristics of light weight and high strength-to-weight ratio. The composite material made by fully mixing it with a thermosetting resin has physical and mechanical properties such as compression resistance and bending resistance comparable to hardwood; bamboo strips are a green bamboo material, and have good development prospects under the background of "carbon neutrality" and "carbon peak". In the present invention, the preparation method of the bamboo strips refers to patent CN110587740A; the preparation method of the bamboo fiber yarn refers to patent CN212316536U; the preparation method of the bamboo fiber felt refers to patent CN113492472A.

[0036] In the present invention, the fixed thickness of the bamboo strips is preferably 0.01-10 mm, more preferably 0.5-1 mm; the fixed width is preferably 0.1-20 mm, more preferably 5-7 mm; and the bamboo strips are preferably continuous and uniform thin bamboo strips.

[0037] In the present invention, the bamboo fiber felt is preferably a continuous bamboo fiber felt; the thickness of the bamboo fiber felt is preferably 10 to 200 mm, and the width is preferably 10 to 2000 mm.

[0038] In the present invention, the initial temperature of the thermosetting resin compound system is preferably 10-60°C lower than the curing temperature of the thermosetting resin compound system itself, so as to keep the thermosetting resin compound system in an uncured state and shorten the curing time to achieve a better curing effect.

[0039] In the present invention, the thermosetting resin compound system preferably includes the following raw materials in terms of weight: 20 to 60 parts of thermosetting resin matrix, 1 to 30 parts of curing agent, and 1 to 130 parts of auxiliary agent; the auxiliary agent includes at least one of glass microspheres, accelerators, interface modifiers, thickeners, antioxidants, ultraviolet absorbers, light stabilizers, toughening agents, flame retardants, fillers, thixotropic agents, and fillers. In the present invention, the viscosity of the thermosetting resin compound system is preferably 10 -2 ~10 3 Pa·s. In a specific embodiment of the present invention, when the thermosetting resin compound system is composed of epoxy resin, curing agent, accelerator and interface modifier, the mass ratio of the epoxy resin, curing agent, accelerator and interface modifier is 15:9:2:5; when the thermosetting resin compound system is composed of epoxy resin, curing agent, interface modifier and thickener, the mass ratio of the epoxy resin, curing agent, interface modifier and thickener is 4:1:0.1:0.5; when the thermosetting resin compound system is composed of epoxy resin, curing agent, accelerator, interface modifier and thickener, the mass ratio of the epoxy resin, curing agent, interface modifier and thickener is 15:9:2:5; The mass ratio of epoxy resin, curing agent, accelerator, interface modifier and thickener is 100:20:8:0.5:2; when the thermosetting resin compound system consists of epoxy resin, curing agent, interface modifier, toughening agent and accelerator, the mass ratio of epoxy resin, curing agent, interface modifier, toughening agent and accelerator is 100:25:1:20:1; when the thermosetting resin compound system consists of epoxy resin, curing agent, interface modifier and accelerator, the mass ratio of epoxy resin, curing agent, interface modifier and accelerator is 100:40:1:0.5.

[0040] In the present invention, the thermosetting resin matrix preferably includes one or more of epoxy resin, unsaturated polyester, fat-soluble phenolic resin, amino resin, polyurethane resin and silicone resin; the epoxy resin is preferably epoxy resin E54, epoxy resin E52 or epoxy resin E56; the curing agent is preferably methyltetrahydrophthalic anhydride, isophoronediamine, aminophenolic resin, polyamide or tung oil anhydride; the particle size of the glass microbeads is preferably 0.1 to 1000 μm; the accelerator is preferably methyldiethanolamine, dimethylimidazole or resorcinol; the interface modifier is preferably KH550, KH560; the thickener is preferably flour or calcium carbonate; the toughening agent is preferably terminal amino nitrile rubber. In the present invention, the flame retardant is preferably a mixture of an alkali, an environmentally friendly flame retardant FPK8002 and a silane coupling agent; the alkali is preferably aluminum hydroxide; the silane coupling agent is preferably KH550; in terms of mass parts, the flame retardant includes 1 to 30 parts of alkali, 1 to 50 parts of environmentally friendly flame retardant FPK8002, and 1 to 30 parts of silane coupling agent.

[0041] The invention can provide storage and molding conditions for a thermosetting resin compound system and a prepreg by adding a curing agent and an accelerator to a thermosetting resin; different additives can provide the thermosetting resin compound system with high tensile strength, high resilience and high conductivity characteristics; by adding an interface modifier to the thermosetting resin, the interface wetting and bonding performance between the thermosetting resin compound system and a continuous bamboo fiber substrate can be improved; by adding glass microbeads to the thermosetting resin, the thermal insulation, sound insulation and damping performance of the thermosetting bamboo fiber prepreg can be improved; the problems of high brittleness, low elongation, poor wettability with bamboo fibers and high low-temperature storage and transportation costs of the thermosetting prepreg in the prior art are solved.

[0042] In the present invention, the preparation method of the thermosetting resin compound system preferably comprises the following steps: heating the thermosetting resin matrix to 40-110° C., adding a curing agent and an auxiliary agent in sequence under stirring conditions, and obtaining a thermosetting resin compound system. In the present invention, the stirring speed is preferably 1-6000 r / min, more preferably 200-500 r / min. In the present invention, when the auxiliary agent includes multiple components, the present invention has no special requirements for the order of adding the auxiliary agents, and the conventional practice in the art can be followed.

[0043] The present invention does not specifically limit the usage ratio of the continuous bamboo fiber substrate and the thermosetting resin compound system, and it is sufficient to ensure that the continuous bamboo fiber substrate can be completely immersed in the thermosetting resin compound system. In a specific embodiment of the present invention, it is preferred to place the thermosetting resin compound system in a glue tank, and then place the continuous bamboo fiber substrate in the thermosetting resin compound system for roller impregnation.

[0044] In the present invention, the pre-tension of the roller impregnation is preferably 1-50N, more preferably 10-15N; the roller spacing is preferably 1-100mm, more preferably 8-15mm; the roller impregnation temperature is preferably 10-200°C, more preferably 50-80°C. The present invention controls the above parameters to promote the compression and swelling of bamboo fiber materials, reduce the viscosity of the thermosetting resin compound system, and ultimately improve the impregnation effect of the thermosetting resin compound system and reduce the inter-fiber pores.

[0045] During the roller impregnation process, on the one hand, the thermosetting resin compound system penetrates between the fibers and inside the fibers to form "glue nails"; on the other hand, the thermosetting resin compound system forms hydrogen bonds with the bamboo fibers, wherein the interfacial modifier acts as a bridge to chemically bond the epoxy resin and the bamboo fibers, thereby improving the interfacial compatibility of the epoxy resin and the bamboo fibers.

[0046] The present invention separates the glue injection and hot pressing processes in the traditional preparation process, improves the glue dipping process, and the roller pressing process is conducive to the infiltration of the glue liquid, so that the moisture in the raw materials and the air in the contact part between the continuous bamboo fiber substrate and the epoxy resin are fully discharged, the bamboo fiber is fully in contact with and infiltrated with the thermosetting resin compound system, the generation and movement of pores are controlled, and the resin content is also controlled from the raw material preparation stage.

[0047] After obtaining the impregnated bamboo fiber system, the present invention performs hot pressing pretreatment on the impregnated bamboo fiber system, and after the obtained system is shaped, performs film coating to obtain a thermosetting bamboo fiber prepreg. In the present invention, the hot pressing pretreatment is preferably performed in a conventional hot press; the temperature of the hot pressing pretreatment is preferably 50 to 300° C., more preferably 100 to 150° C.; the fixed thickness is preferably 1 to 50 mm, more preferably 5 to 10 mm; the time is preferably 10 to 120 min, more preferably 40 to 60 min.

[0048] In the present invention, after the hot pressing pretreatment, the obtained system is preferably cooled to prevent solidification and facilitate storage. In the present invention, the cooling temperature is preferably -20 to 10°C, more preferably 3°C.

[0049] In the present invention, the thermosetting bamboo fiber prepreg is preferably in a gel state, and the curing degree of the thermosetting bamboo fiber prepreg is preferably 60-90%, which is in the diffusion reaction control stage, has a short service life, can be directly molded and cured, and improves the preparation efficiency of the composite material.

[0050] In the present invention, the laminating method preferably comprises: first placing a thermoplastic film at the bottom of the concave groove, and then pouring the impregnated bamboo fiber system into the concave groove for sealing. In the present invention, the thermoplastic film is preferably commercially available PA12, PA11, PA66 or PA6, and the thickness of the thermoplastic film is preferably 0.1 to 10 mm. The present invention has no special requirements for the specific sealing process, and the sealing process well known to those skilled in the art can be used.

[0051] The present invention improves the impregnation process so that the internal pores of the thermosetting bamboo fiber prepreg are controlled. Since the prepared thermosetting bamboo fiber prepreg itself is not completely cured to form a three-dimensional network structure, during the storage process, the thermosetting bamboo fiber prepreg in a gel state will continue to chemically react with the hydroxyl groups of the bamboo fiber. Therefore, the interface performance is better than that of traditional bamboo fiber epoxy composite materials, and the storage period can be extended.

[0052] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. 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.

[0053] Example 1

[0054] Preparation of thermosetting resin compound system: Liquid epoxy resin E54 was uniformly stirred at a speed of 200 r / min, heated to 70°C, and curing agent methyltetrahydrophthalic anhydride and accelerator dimethylimidazole were added in sequence, followed by adding interface modifier KH550, wherein the mass ratio of liquid epoxy resin E54, methyltetrahydrophthalic anhydride, dimethylimidazole and interface modifier was 15:9:2:5, and stirred at a high speed until the mixture was uniform to obtain a thermosetting resin compound system, which was poured into a glue tank;

[0055] Preparation of continuous bamboo fiber felt: Split bamboo into pieces, soak them in water for 24 hours, and then mechanically roll, loosen and dry them to obtain crude fibers; then comb, orientedly spread and roller-set the thickness of the crude fibers to obtain continuous bamboo fiber felt; the feeding speed of the oriented spread is 6 m / min, the roller-set thickness is 15 mm, and the set width is 350 mm;

[0056] Preparation of gel-state bamboo fiber felt prepreg (roller impregnation): immerse the continuous bamboo fiber felt in a thermosetting resin compound system, set the roller spacing to 8 mm, pre-tension to 10 N, glue tank temperature to 50 ° C, and perform hot pressing pretreatment after impregnation. The hot pressing pretreatment temperature is 100 ° C, the thickness is set to 5 mm, the time is 40 min, and the excess glue is removed to make the epoxy system reach a gel state, cool and coat, and roll up.

[0057] The gel-state bamboo fiber felt prepreg performance: surface density is 800g / m 2 , resin content is 45%, applicable period is 72h at room temperature, and 150h at -10℃.

[0058] Preparation of continuous bamboo fiber composite door and window frames: under the traction of an external force of 50N, pre-forming, hot mold curing, fixed-length cutting or post-processing under continuous demolding are performed to obtain continuous bamboo fiber composite door and window frames; the traction speed is 200mm / min; the pre-forming temperature is 80℃; the pre-forming time is 40min; the pre-forming pressure is 20N; the curing temperature is 140℃; the curing time is 60min; the curing pressure is 5MPa.

[0059] The continuous bamboo fiber composite door and window frame prepared in this embodiment has a tensile strength (test standard is GB / T 1447-2005) of 400 MPa, a flexural strength of 420 MPa, and a thermal conductivity of 0.18 W / (m·K).

[0060] Example 2

[0061] Preparation of thermosetting resin compound system: Mix polyether polyol and isocyanate (purchased two-component polyurethane AB glue, directly mixed), the mass ratio of polyether polyol to isocyanate is 5:6, stir at high speed until the mixture is uniform, obtain a thermosetting resin compound system, and pour it into the glue tank;

[0062] Preparation of bamboo strips: split the bamboo strips into strips with a width of 7mm and a thickness of 1mm, and continuously connect them into rolls for later use;

[0063] Preparation of bamboo strip prepreg (roller impregnation): immerse the bamboo strip in a thermosetting resin compound system, set the roller spacing to 15 mm, pre-tension to 15 N, glue tank temperature to 60 ° C, and perform hot pressing pretreatment after impregnation. The hot pressing pretreatment temperature is 100 ° C, the thickness is set to 10 mm, the time is 60 min, and the excess glue is removed to make the system reach a gel state, cool and coat, and reel.

[0064] The bamboo strip prepreg performance: surface density is 750g / m 2 , resin content is 20%, applicable period is 48h at room temperature, and 150h at -10℃.

[0065] Preparation of continuous bamboo fiber composite door and window frames: under the traction of 60N external force, preforming, hot mold curing, fixed-length cutting or post-processing under continuous demolding, to obtain continuous bamboo fiber composite door and window frames; the traction speed is 200mm / min; the preforming temperature is 80℃; the preforming time is 30min; the preforming pressure is 15N; the curing temperature is 180℃; the curing time is 60min; the curing pressure is 5MPa.

[0066] The continuous bamboo fiber composite door and window frame prepared in this embodiment has a tensile strength (test standard is GB / T 1447-2005) of 450 MPa, a bending strength of 480 MPa, and a thermal conductivity of 0.16 W / (m·K).

[0067] Example 3

[0068] Preparation of thermosetting resin compound system: Mix polyether polyol and isocyanate (purchased two-component polyurethane AB glue, directly mix), add toughening agent terminal amino nitrile rubber, the mass ratio of polyether polyol to isocyanate is 5:6, stir at high speed until the mixture is uniform, obtain a thermosetting resin compound system, and pour it into the glue tank;

[0069] Preparation of bamboo strips: split bamboo strips into strips with a width of 5 mm and a thickness of 0.5 mm, and continuously connect them into rolls for later use;

[0070] Preparation of bamboo strip prepreg (roller impregnation): immerse the bamboo strip in a thermosetting resin compound system, set the roller spacing to 15 mm, pre-tension to 15 N, glue tank temperature to 60 ° C, and perform hot pressing pretreatment after impregnation. The hot pressing pretreatment temperature is 90 ° C, the thickness is set to 10 mm, the time is 60 min, and the excess glue is removed to make the system reach a gel state, cool and coat, and reel.

[0071] The bamboo strip prepreg performance: surface density is 800g / m 2 , resin content is 25%, applicable period is 48h at room temperature, and 150h at -10℃.

[0072] Preparation of continuous bamboo fiber composite door and window frames: under the traction of 60N external force, preforming, hot mold curing, fixed-length cutting or post-processing under continuous demolding, to obtain continuous bamboo fiber composite door and window frames; the traction speed is 150mm / min; the preforming temperature is 100℃; the preforming time is 60min; the preforming pressure is 20N; the curing temperature is 180℃; the curing time is 60min; the curing pressure is 5MPa.

[0073] The continuous bamboo fiber composite door and window frame prepared in this embodiment has a tensile strength (test standard is GB / T 1447-2005) of 480 MPa, a bending strength of 500 MPa, and a thermal conductivity of 0.16 W / (m·K).

[0074] Example 4

[0075] Preparation of thermosetting resin compound system: liquid epoxy resin E54 is uniformly stirred at a high speed of 200 r / min, heated to 70°C, and curing agent methyltetrahydrophthalic anhydride and accelerator dimethylimidazole are added in sequence, followed by adding flame retardant (the mass ratio of aluminum hydroxide, environmentally friendly flame retardant FPK8002 and silane coupling agent KH550 is 1:2:1), the mass ratio of liquid epoxy resin E54, methyltetrahydrophthalic anhydride, dimethylimidazole and flame retardant is 15:9:2:3, and stirred at a high speed until the mixture is uniform to obtain a thermosetting resin compound system, which is poured into a glue tank;

[0076] Preparation of continuous bamboo fiber felt: Split bamboo into pieces, soak them in water for 24 hours, and then mechanically roll, loosen and dry them to obtain crude fibers; then comb, orientedly spread and roller-set the thickness of the crude fibers to obtain continuous bamboo fiber felt; the feeding speed of the oriented spread is 6 m / min, the roller-set thickness is 15 mm, and the set width is 350 mm;

[0077] Preparation of gel-state bamboo fiber felt prepreg (roller impregnation): immerse the continuous bamboo fiber felt in a thermosetting resin compound system, set the roller spacing to 8 mm, pre-tension to 10 N, glue tank temperature to 50 ° C, and perform hot pressing pretreatment after impregnation. The hot pressing pretreatment temperature is 100 ° C, the thickness is set to 5 mm, the time is 40 min, and the excess glue is removed to make the epoxy system reach a gel state, cool and coat, and roll up.

[0078] The gel-state bamboo fiber felt prepreg has a surface density of 780 g / m 2 , resin content is 42%, applicable period is 72h at room temperature, and 150h at -10℃.

[0079] Preparation of continuous bamboo fiber composite door and window frames: under the traction of an external force of 50N, pre-forming, hot mold curing, fixed-length cutting or post-processing under continuous demolding are performed to obtain continuous bamboo fiber composite door and window frames; the traction speed is 200mm / min; the pre-forming temperature is 80℃; the pre-forming time is 40min; the pre-forming pressure is 20N; the curing temperature is 140℃; the curing time is 60min; the curing pressure is 5MPa.

[0080] The continuous bamboo fiber composite door and window frame prepared in this embodiment has a tensile strength (test standard is GB / T 1447-2005) of 395 MPa, a flexural strength of 400 MPa, and a thermal conductivity of 0.21 W / (m·K), which meets the requirements of the German standard DIN4102-1 "Fire resistance of building materials and components Part 1: Classification and grades of requirements and tests for building materials".

[0081] Figure 1 This is a model diagram of the continuous bamboo fiber composite door and window frame prepared in the embodiment. Figure 2 Schematic diagram of the continuous bamboo fiber composite door and window frame prepared in Example 1. Figures 1-2 It can be seen that the door and window frames made of continuous bamboo fiber composite materials can have better design and save the amount of composite materials while meeting the mechanical properties.

[0082] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a continuous bamboo fiber composite door and window frame, comprising the following steps: Under external traction, the thermosetting bamboo fiber prepreg is preformed and cured in sequence to obtain a continuous bamboo fiber composite door and window frame; The traction speed of the external force traction is 100~350mm / min; The preforming temperature is 50-350°C; the preforming time is 10-120 minutes; the preforming pressure is 1-100N; The curing temperature is 100-250°C; the curing time is 30-120min; the curing pressure is 1-20MPa; The preparation method of the thermosetting bamboo fiber prepreg comprises the following steps: The continuous bamboo fiber substrate is placed in a thermosetting resin compound system and roller impregnated to obtain a resin-impregnated bamboo fiber system; the continuous bamboo fiber substrate is a bamboo fiber felt; The resin-impregnated bamboo fiber system is subjected to heat-pressing pretreatment, and after the obtained system is shaped, a film is applied to obtain a thermosetting bamboo fiber prepreg; The resin content of the thermosetting bamboo fiber prepreg is 42-45%.

2. The method for preparing a continuous bamboo fiber composite door and window frame according to claim 1, characterized in that: The initial temperature of the thermosetting resin compound system is 10-60° C. lower than the curing temperature of the thermosetting resin compound system itself.

3. The method for preparing a continuous bamboo fiber composite door and window frame according to claim 1, characterized in that: The pre-tension of the roller dipping is 1-50N, and the roller spacing is 1-100mm.

4. The method for preparing a continuous bamboo fiber composite door and window frame according to claim 1, characterized in that: The temperature of the hot pressing pretreatment is 90-120° C., the pressure is 0.01-5 MPa, and the time is 1-60 min.

5. The method for preparing a continuous bamboo fiber composite door and window frame according to claim 1, characterized in that: The thermosetting bamboo fiber prepreg is in a gel state.

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