阅读说明：本技术 空心弧形管状复合材料的制备方法 (Preparation method of hollow arc-shaped tubular composite material ) 是由 王一靓 刘婷 左景奇 王明星 吴祖胜 杨名波 易晓娟 于 2021-08-02 设计创作，主要内容包括：本发明公开了一种空心弧形管状复合材料的制备方法,该方法包括在棒状芯模上依次缠绕导流布、脱模布和增强材料,经除湿、加热、脱模,得预制体；将树脂导流管穿设于预制体的内腔中,然后树脂导流管内放入管状真空袋套,再将预制体放入模具中,模具的型腔呈弧形管状结构；对模具抽真空,将树脂体系导入模具中,使树脂体系将预制体浸渍,经固化、脱模,得到空心弧形管状复合材料。本发明的制备方法速度快、效率高、成本低,且原料可分开贮存,产品质量好。(The invention discloses a preparation method of a hollow arc-shaped tubular composite material, which comprises the steps of sequentially winding a flow guide cloth, a demolding cloth and a reinforcing material on a rod-shaped core mold, and dehumidifying, heating and demolding to obtain a prefabricated body; the resin guide pipe is arranged in an inner cavity of the prefabricated part in a penetrating manner, then a tubular vacuum bag sleeve is arranged in the resin guide pipe, and then the prefabricated part is arranged in a mould, wherein a cavity of the mould is of an arc-shaped tubular structure; and vacuumizing the mould, introducing the resin system into the mould, impregnating the preform by the resin system, and curing and demoulding to obtain the hollow arc-shaped tubular composite material. The preparation method of the invention has the advantages of high speed, high efficiency, low cost, separable storage of raw materials and good product quality.)

1. The preparation method of the hollow arc-shaped tubular composite material is characterized by comprising the following steps of:

s1, preforming of a reinforcing material: sequentially winding a flow guide cloth (2), a demolding cloth (3) and a reinforcing material (4) on a rod-shaped core mold (1), heating and drying moisture after dehumidification, and removing the rod-shaped core mold (1) to obtain a prefabricated body with an inner cavity;

s2, placing into a mold for sealing: the resin guide pipe is arranged in an inner cavity of the prefabricated body in a penetrating mode, then a tubular vacuum bag sleeve is arranged in the resin guide pipe, the prefabricated body containing the resin guide pipe and the tubular vacuum bag sleeve is obtained, the prefabricated body containing the resin guide pipe and the tubular vacuum bag sleeve is placed into a mold, and a cavity of the mold is of an arc-shaped tubular structure;

s3, resin vacuum infusion: vacuumizing a mould filled with a preform, introducing a prepared resin system into the mould to enable the resin system to impregnate the preform, wherein the mass ratio of the resin system to a reinforcing material in the preform is 1.75-2: 3, and demoulding after curing to obtain the hollow arc-shaped tubular composite material.

2. The method for preparing a hollow arc-shaped tubular composite material according to claim 1, wherein in step S1, the reinforcing material is a fiber fabric, the fiber fabric is a plain cloth and/or a twill cloth, and the fiber fabric is a mixture of one or more than two of glass fiber, basalt fiber, polyester fiber and aramid fiber; and/or in step S1, winding 2-10 layers of the reinforcing material at the preset corner of the product.

3. The method for preparing a hollow arc-shaped tubular composite material according to claim 2, wherein in step S3, the viscosity of the resin system at normal temperature is 200mPa · S to 1500mPa · S, the resin system is an epoxy resin system, a polyurethane resin system or a vinyl resin system, the epoxy resin system comprises an epoxy resin, a curing agent and an accelerator, and the polyurethane resin system comprises diphenylmethane diisocyanate, polyether polyol, a catalyst and a chain extender.

4. The method for preparing the hollow arc-shaped tubular composite material according to claim 3, wherein in step S3, the curing agent is methyl tetrahydrophthalic anhydride, the accelerator is modified imidazole or modified sulfenamide, the catalyst is an organotin catalyst, and the chain extender is 1, 4-butanediol or ethylenediamine;

the polyurethane resin comprises, by mass, 100 parts of epoxy resin, 20-30 parts of a curing agent and 0.2-1 part of an accelerator in an epoxy resin system, 100 parts of diphenylmethane diisocyanate, 35-50 parts of polyether polyol, 0.5-5 parts of a catalyst and 0.5-3 parts of a chain extender in a polyurethane resin system.

5. The method for preparing a hollow arc-shaped tubular composite material according to claim 4, wherein in the step S3, the resin system is prepared by the following steps: mixing and stirring the raw materials under the conditions of temperature of 60-70 ℃ and rotating speed of 400-500 rpm, and carrying out vacuum defoaming for 1-2 h under-0.08 MPa-0.09 MPa to obtain a resin system; the conditions for introducing the resin system are: the temperature is 60-80 ℃, the vacuum degree is-0.08 MPa to-0.09 MPa, the pressure is maintained after impregnation, the pressure maintaining is-0.4 MPa to-0.6 MPa, and the pressure maintaining time is 1h to 2 h.

6. The method for preparing the hollow arc-shaped tubular composite material according to any one of claims 1 to 5, wherein in the step S3, the curing process is as follows: curing for 4-6 h at 70-90 ℃ and curing for 10-12 h at 110-130 ℃.

7. The preparation method of the hollow arc-shaped tubular composite material according to any one of claims 1 to 5, it is characterized in that the die comprises an upper die (6) and a lower die (7), the upper die (6) is provided with an upper die cavity (8), the lower die (7) is provided with a lower die cavity (9), a die cavity formed by the upper die cavity (8) and the lower die cavity (9) during die assembly is of an arc-shaped tubular structure, sealing strips (14) are respectively arranged on both sides of the upper die cavity (8) and both sides of the lower die cavity (9), the upper die (6) is provided with a through hole (15), the lower die (7) is provided with a connecting hole (10), the through hole (15) is connected with the connecting hole (10) through a locking device (11), the upper die (6) is further provided with a positioning pin (12), and the lower die (7) is further provided with a positioning hole (13) connected with the positioning pin (12).

8. The method for preparing a hollow arc-shaped tubular composite material according to any one of claims 1 to 5, wherein in step S1, the length of the rod-shaped core mold (1) is greater than or equal to the preset length of the product, the length of the release fabric (3) is greater than or equal to the preset length of the product, the winding thickness of the reinforcing material (4) is the same as or approximately the same as the preset thickness of the product, and the product is the hollow arc-shaped tubular composite material.

9. The preparation method of the hollow arc-shaped tubular composite material according to any one of claims 1 to 5, wherein in the step S1, the dehumidification temperature is 90 ℃ to 120 ℃, the dehumidification vacuum degree is-0.08 MPa to-0.09 MPa, the dehumidification time is 6h to 8h, and the temperature for heating and drying the water is 80 ℃ to 120 ℃.

10. The method for preparing a hollow arc-shaped tubular composite material according to any one of claims 1 to 5, wherein in step S2, after the preform comprising the resin guide tube and the tubular vacuum bag sleeve is placed in the mold, the two ends of the tubular vacuum bag sleeve are turned outwards to be tightly attached to the mold for sealing, and the resin guide tube is tightly attached to the tubular vacuum bag sleeve.

Technical Field

The invention belongs to the technical field of composite material preparation, and particularly relates to a preparation method of a hollow arc-shaped tubular composite material.

Background

At present, the common forming method for the hollow composite material is winding forming, but the tubular composite material with irregular arc shape is difficult to complete demoulding and form. The soft material is adopted as the core mould, and the core mould can be damaged after being used for a plurality of times, so that the durability is poor. The manual work is laid, and production efficiency is low, can not reach once continuous molding. The chinese patent document CN108501397 discloses a method for preparing an arc-shaped tube by using a straight inner core mold, and discloses a method for preparing an arc-shaped tube by using a straight inner core mold, which is considered more convenient when prepreg is laid on the straight inner core mold, and can ensure that the laying angle of the prepreg meets the design requirement of the integral laying angle of the arc-shaped tube, but the prepreg preparation process is complicated and needs special equipment for preparation, for example, the conventional production method of the prepreg is to use a resin composition taking resin as a main component as a glue solution, impregnate a glass fiber cloth substrate with the glue solution in a glue tank, precisely control the resin content by a metering roller, heat and dry the glue solution in an oven to prepare a prepreg, because the moisture absorption and high-temperature storage of the prepreg are cured, the prepreg must be stored under a closed condition, and the prepreg needs low temperature or refrigeration during transportation and storage, can be stored for only a short time at the normal room temperature of 20-25 ℃, has high requirements on equipment and environment and has high cost. Due to the fact that the content of the prepreg resin is low, layering and air holes are prone to being generated in a thickening area and a corner area, and product performance and appearance quality are affected. Therefore, there is a need to develop new methods for preparing hollow composite materials.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a preparation method of a hollow arc-shaped tubular composite material, which has the advantages of high forming efficiency, high speed, good quality, low cost and convenient storage.

In order to solve the technical problems, the invention adopts the following technical scheme.

A preparation method of a hollow arc-shaped tubular composite material comprises the following steps:

s1, preforming of a reinforcing material: sequentially winding a flow guide cloth, a demolding cloth and a reinforcing material on the rod-shaped core mold, heating and drying moisture after dehumidification, and removing the rod-shaped core mold to obtain a prefabricated body with an inner cavity;

s2, placing into a mold for sealing: the resin guide pipe is arranged in an inner cavity of the prefabricated body in a penetrating mode, then a tubular vacuum bag sleeve is arranged in the resin guide pipe, the prefabricated body containing the resin guide pipe and the tubular vacuum bag sleeve is obtained, the prefabricated body containing the resin guide pipe and the tubular vacuum bag sleeve is placed into a mold, and a cavity of the mold is of an arc-shaped tubular structure;

s3, resin vacuum infusion: vacuumizing a mould filled with a preform, introducing a prepared resin system into the mould to enable the resin system to impregnate the preform, wherein the mass ratio of the resin system to a reinforcing material in the preform is 1.75-2: 3, and demoulding after curing to obtain the hollow arc-shaped tubular composite material.

In the above preparation method of the hollow arc-shaped tubular composite material, preferably, in step S1, the reinforcing material is a fiber fabric, the fiber fabric is a plain cloth and/or a twill cloth, and the fiber fabric is a mixture of one or more than two of glass fibers, basalt fibers, polyester fibers and aramid fibers according to material differentiation; and/or in step S1, winding 2-10 layers of the reinforcing material at the preset corner of the product.

In the above preparation method of the hollow arc-shaped tubular composite material, preferably, in step S3, the viscosity of the resin system at normal temperature is 200mPa · S to 1500mPa · S, the resin system is an epoxy resin system, a polyurethane resin system or a vinyl resin system, the epoxy resin system includes an epoxy resin, a curing agent and an accelerator, and the polyurethane resin system includes diphenylmethane diisocyanate, polyether polyol, a catalyst and a chain extender.

In the above preparation method of the hollow arc-shaped tubular composite material, preferably, in step S3, the curing agent is methyl tetrahydrophthalic anhydride, the accelerator is modified imidazole or modified sulfenamide, the catalyst is an organotin catalyst, and the chain extender is 1, 4-butanediol or ethylenediamine;

the polyurethane resin comprises, by mass, 100 parts of epoxy resin, 20-30 parts of a curing agent and 0.2-1 part of an accelerator in an epoxy resin system, 100 parts of diphenylmethane diisocyanate, 35-50 parts of polyether polyol, 0.5-5 parts of a catalyst and 0.5-3 parts of a chain extender in a polyurethane resin system.

In the above method for preparing a hollow arc-shaped tubular composite material, preferably, in step S3, the resin system is prepared by: mixing and stirring the raw materials under the conditions of temperature of 60-70 ℃ and rotating speed of 400-500 rpm, and carrying out vacuum defoaming for 1-2 h under-0.08 MPa-0.09 MPa to obtain a resin system; the conditions for introducing the resin system are: the temperature is 60-80 ℃, the vacuum degree is-0.08 MPa to-0.09 MPa, the pressure is maintained after impregnation, the pressure maintaining is-0.4 MPa to-0.6 MPa, and the pressure maintaining time is 1h to 2 h.

In the above method for preparing the hollow arc-shaped tubular composite material, preferably, in step S3, the curing process includes: curing for 4-6 h at 70-90 ℃ and curing for 10-12 h at 110-130 ℃.

Preferably, the die comprises an upper die and a lower die, the upper die is provided with an upper die cavity, the lower die is provided with a lower die cavity, a die cavity formed by the upper die cavity and the lower die cavity during die assembly is of an arc-shaped tubular structure, sealing strips are arranged on two sides of the upper die cavity and two sides of the lower die cavity, the upper die is provided with a through hole, the lower die is provided with a connecting hole, the through hole is connected with the connecting hole through a locking device, the upper die is further provided with a positioning pin, and the lower die is further provided with a positioning hole connected with the positioning pin.

Preferably, in the step S1, the length of the rod-shaped core mold is greater than or equal to the preset length of the product, the length of the release fabric is greater than or equal to the preset length of the product, the winding thickness of the reinforcing material is the same as or approximately the same as the preset thickness of the product, and the product is the hollow arc tubular composite material.

Preferably, in the step S1, the temperature of dehumidification is 90 ℃ to 120 ℃, the vacuum degree of dehumidification is-0.08 MPa to-0.09 MPa, the time of dehumidification is 6h to 8h, and the temperature of heating and drying moisture is 80 ℃ to 120 ℃.

Preferably, in the step S2, after the preform containing the resin guide tube and the tubular vacuum bag sleeve is placed in the mold, the two ends of the tubular vacuum bag sleeve are turned outwards to be tightly attached to the mold for sealing, and the resin guide tube is tightly attached to the tubular vacuum bag sleeve.

Compared with the prior art, the invention has the advantages that:

the invention adopts the technical flows of the reinforcing material and the resin to be soaked by the pressurized resin flowing in the die cavity quickly, not expensive mechanical soaking in a prepreg process and an SMC process, or manual soaking in a hand pasting and spraying process. The resin and the reinforcing material can be stored separately in the preparation method, so that the storage is more convenient and the quality guarantee period is longer.

Drawings

FIG. 1 is a schematic view showing the structure of a preform comprising a rod-shaped core mold in example 1 of the present invention.

FIG. 2 is a schematic view showing that a preform including a resin draft tube and a tubular vacuum bag cover according to example 1 of the present invention is put into a mold.

Fig. 3 is a schematic structural view of a hollow arc-shaped tubular composite material in embodiment 1 of the present invention.

Illustration of the drawings:

1. a rod-shaped core film; 2. flow guiding cloth; 3. demolding the cloth; 4. a reinforcing material; 5. the bend is wound with a plurality of reinforcing materials; 6. an upper die; 7. a lower die; 8. an upper mold cavity; 9. a lower die cavity; 10. connecting holes; 11. a locking device; 12. positioning pins; 13. positioning holes; 14. a sealing strip; 15. and a through hole.

Detailed Description

The invention is further described below with reference to the drawings and specific preferred embodiments of the description, without thereby limiting the scope of protection of the invention. The materials and equipment used in the following examples are commercially available.

Example 1:

the invention relates to a preparation method of a hollow arc-shaped tubular composite material, which comprises the following steps:

s1, preforming of a reinforcing material: winding a circle of guide cloth 2 with half width of 700mm on a cylindrical rod-shaped core mould 1 with the diameter of 10mm and the length of 800mm, then winding a circle of demoulding cloth 3 with half width of 650mm, and then winding a reinforcing material 4 on the demoulding cloth 3 until the outer diameter reaches 22mm, as shown in figure 1, winding 4 layers of reinforcing materials with the width of 40mm at a position 150mm away from the left end of the reinforcing material 4 to be used as reinforcing materials 5 wound at a turning position, and winding 4 layers of reinforcing materials with the width of 40mm at a position 100mm away from the right end of the reinforcing materials, namely the reinforcing materials 5 wound at the turning position, wherein the width directions of the guide cloth 2, the demoulding cloth 3 and the reinforcing materials 4 are the length direction of the rod-shaped core mould 1. Dehumidifying for 8h at 100 ℃ and vacuum degree of-0.09 MPa, heating and drying at 105 ℃, and removing the rod-shaped core mold 1 to obtain a preform with an inner cavity.

S2, placing into a mold for sealing: and (3) arranging the resin guide pipe in an inner cavity of the prefabricated body in a penetrating manner, then arranging a tubular vacuum bag sleeve in the resin guide pipe in a penetrating manner, and enabling one end of the tubular vacuum bag sleeve to be located at the resin injection inlet end and the other end of the tubular vacuum bag sleeve to be located at the resin collection port end to obtain the prefabricated body containing the resin guide pipe and the tubular vacuum bag sleeve. The preform containing the resin guide pipe and the tubular vacuum bag sleeve is placed into a mold (outer mold), as shown in fig. 2, a cavity of the mold is in an arc-shaped tubular structure and is locked, sealing rubber strips are attached to two ends of the outer side of the tubular vacuum bag sleeve, two ends of the tubular vacuum bag sleeve are turned outwards to be tightly attached to the mold for sealing, and the resin guide pipe is tightly attached to the tubular vacuum bag sleeve.

S3, resin vacuum infusion: vacuumizing the whole system, introducing a prepared resin system into a mold under the conditions of 70 ℃ and-0.09 MPa of vacuum degree, enabling the resin system to flow in by itself, impregnating the preform in the mold under pressure by the resin system, keeping the mass ratio of the resin system to the reinforcing material in the preform to be 1.9: 3, keeping the pressure after impregnation, keeping the pressure to be-0.6 MPa, keeping the pressure for 1.5h, curing after keeping the pressure, curing at 80 ℃ for 6h, curing at 120 ℃ for 11h, and then demolding to obtain the hollow arc-shaped tubular composite material, wherein the length is 650mm, and the outer diameter reaches 22mm, as shown in figure 3.

In step S1, the reinforcing material is fiberglass plain cloth with a single thickness of 0.1mm, and the reinforcing material is wound by 4 layers at the corner turn preset in the product, and the angle of the corner is usually greater than 20 °.

In step S2 and step S3 of this embodiment, as shown in fig. 2, the mold includes an upper mold 6 and a lower mold 7, the upper mold 6 is provided with an upper mold cavity 8, the lower mold 7 is provided with a lower mold cavity 9, during mold closing, the upper mold cavity 8 and the lower mold cavity 9 form a mold cavity, the mold cavity is in an arc-shaped tubular structure, two sides of the upper mold cavity 8 and two sides of the lower mold cavity 9 are both provided with a sealing groove, a sealing strip 14 is installed in the sealing groove, through holes 15 are formed around the upper mold 6, connecting holes 10 are formed around the lower mold 7, the through holes 15 are connected with the connecting holes 10 through a locking device 11, in this embodiment, the locking device 11 is specifically a bolt, positioning pins 12 are further arranged around the upper mold 6, and positioning holes 13 connected with the positioning pins 12 are further formed around the lower mold 7.

In step S3 of this embodiment, the resin system is an epoxy resin system, the epoxy resin system includes an epoxy resin, a curing agent and an accelerator, the curing agent is methyl tetrahydrophthalic anhydride, and the accelerator is a modified imidazole, specifically a 2-ethyl-4-methylimidazole accelerator, and the epoxy resin, the curing agent and the accelerator are respectively 100 parts, 25 parts and 0.5 part by mass. The viscosity of the resin system was 700 mPas at room temperature.

The preparation process of the resin system comprises the following steps: under the conditions of 70 ℃ and 500rpm, all raw materials of the resin system are mixed and stirred, and vacuum defoamation is carried out for 1.5h under-0.09 MPa to obtain a resin mixed material, namely the resin system.

The hollow arc-shaped tubular composite material prepared by the invention is convenient to store, can be stored for a long time at room temperature, and has high resin content and good mechanical property through detection as shown in table 1.

TABLE 1 Performance parameters of hollow curved tubular composites prepared in inventive example 1

Item	Performance index	Detection standard
			Product appearance	Densification of
Tensile strength/MPa	470	GB/T 1040.4-2006
			Flexural Strength/MPa	374	GB/T 9341-2008
Flexural modulus/MPa	18245	GB/T 9341-2008
			Content of resin/%)	41	GB/T2577-2005

The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make many possible variations and modifications to the disclosed embodiments, or equivalent modifications, without departing from the spirit and scope of the invention, using the methods and techniques disclosed above. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are still within the scope of the protection of the technical solution of the present invention.