A method for forming a complex structure composite material by segmental lay-up and curing

Abstract

The application is a kind of complex structure composite material segmented laying curing forming method, and belongs to the technical field of composite material forming. Its characteristics are as follows: step one, covering prepreg on the surface of complex structure to obtain prepreg layer complex structure; step two, covering dense sealing material on the surface of the prepreg layer complex structure, vacuumizing and then pressure maintaining; then curing after removing the dense sealing material to obtain the laminated layer complex structure; step three, repeating step one and step two on the surface of the laminated layer complex structure until reaching the target thickness to obtain the composite material complex structure. The application is suitable for different complex structures, and the corresponding segmented prepreg laying is carried out according to different complex structures, so that the adaptability is strong, the practical effect is good, the curing effect of deep composite material is optimized through step curing, the laying failure problem caused by poor laminating and curing effect of complex structure for a long time is solved, the comprehensive benefit is good, and the application prospect is wide.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of composite material processing, and particularly relates to a sectional laying and curing forming method for a composite material with a complex structure. BACKGROUND

[0002] As a commonly used structural and functional material, a composite material is widely used in the fields of aerospace, high-speed trains, construction engineering and equipment manufacturing, and endows the material with specific functions or improves the overall performance of the material. Among them, the composite material as an outer protective layer is also a common composite material application scene combined with traditional materials.

[0003] As a structural support, the commonly used laying methods of the composite material include a mechanical method, a laying method and a pre-impregnation method. Among them, the pre-impregnation method is increasingly widely applied due to its excellent laying effect. However, the pre-impregnation method also has some problems, for example, it can guarantee the laying effect for a conventional structure, but it has poor adaptability for a complex structure, the process is complex, and the laying effect cannot be well guaranteed. SUMMARY

[0004] The purpose of the application is to provide a sectional laying and curing forming method for a composite material with a complex structure. The laying method provided by the application has simple steps and good laying effect.

[0005] A sectional laying and curing forming method for a composite material with a complex structure, characterized in that the method comprises the following steps:

[0006] Step one, covering a pre-impregnated material on the surface of the complex structure to obtain a pre-impregnated material layer complex structure;

[0007] Step two, covering a dense sealing material on the surface of the pre-impregnated material layer complex structure, vacuumizing and then pressure-keeping, and then curing after removing the dense sealing material to obtain a laminated layer complex structure;

[0008] Step three, repeating steps one and two on the surface of the laminated layer complex structure until the target thickness is reached to obtain a composite material complex structure.

[0009] In step one, the thickness of the pre-impregnated material is 0.05-0.25 mm.

[0010] In step two, the target vacuum degree of the vacuumizing is 1x10 -3 -1x10 -5 Pa.

[0011] In step two, the pressure-keeping time is 0.5-5 h.

[0012] In step three, the target thickness is not more than 8 mm.

[0013] The curing in the step two is sectional curing; the sectional curing comprises sequentially performing a first curing section, a second curing section and a third curing section.

[0014] The temperature of the first curing section is 80-110 DEG C, the vacuum degree is 1x10 -3 ~ 1x10 -5 Pa, and the curing time is 0.5-3h.

[0015] The temperature of the second curing section is 120-280 DEG C, the vacuum degree is 1x10 -3 ~ 1x10 -5 Pa, and the curing time is 1-5h.

[0016] The temperature of the third curing section is 150-380 DEG C, the vacuum degree is 1x10 -4 ~ 1x10 -5 Pa, and the curing time is 0.5-2h.

[0017] The number of repeating the step one and the step two in the step three is not more than 160 times.

[0018] The present application provides a sectional laying and curing forming method for composite material with complex structure. DETAILED DESCRIPTION

[0019] In order to achieve the above object, the present application provides the following technical scheme:

[0020] The present application provides a sectional laying and curing forming method for composite material with complex structure, comprising the following steps:

[0021] (1) covering prepreg on the surface of a complex structure mold cavity to obtain a prepreg layer complex structure;

[0022] (2) covering a dense sealing material on the surface of the prepreg layer complex structure, vacuumizing and pressure maintaining, removing the dense sealing material and curing to obtain a laminated layer complex structure;

[0023] (3) repeating the step one and the step two on the surface of the laminated layer complex structure until the target thickness is reached to obtain a composite material complex structure.

[0024] Preferably, in the step one, the thickness of the prepreg is 0.05-0.25mm.

[0025] Preferably, in step two, the target vacuum degree of the vacuumizing is 1x10 -3 ~1x10 -5 Pa.

[0026] Preferably, in step two, the time of the pressure maintaining is 0.5~5h.

[0027] Preferably, in step three, the target thickness is no more than 5mm.

[0028] Preferably, in step three, the solidifying is sectional solidifying; the sectional solidifying comprises sequentially performing a first solidifying section, a second solidifying section and a third solidifying section.

[0029] Preferably, the temperature of the first solidifying section is 80~110℃, the vacuum degree is 1x10 -3 ~1x10 -5 Pa, and the solidifying time is 0.5~3h.

[0030] Preferably, the temperature of the second solidifying section is 120~280℃, the vacuum degree is 1x10 -3 ~1x10 -5 Pa, and the solidifying time is 1~5h.

[0031] Preferably, the temperature of the third solidifying section is 150~380℃, the vacuum degree is 1x10 -4 ~1x10 -5 Pa, and the solidifying time is 0.5~2h.

[0032] Preferably, in step three, the number of repeating steps one and two is no more than 160.

[0033] The present application provides a sectional laying and solidifying forming method of composite material with complex structure, comprising the following steps:

[0034] (1) covering prepreg on the surface of a mold cavity with complex structure to obtain a prepreg layer with complex structure;

[0035] (2) covering dense sealing material on the surface of the prepreg layer with complex structure, vacuumizing, and then sequentially performing pressure maintaining and solidifying to obtain a laminated layer with complex structure;

[0036] (3) repeating steps one and two on the surface of the laminated layer with complex structure until the target thickness is reached.

[0037] The present application covers prepreg on the surface of a complex structure to obtain a prepreg layer with complex structure. In the present application, the prepreg is preferably epoxy resin prepreg, bismaleimide resin prepreg, polyimide resin prepreg, and more preferably epoxy resin prepreg.

[0038] In this invention, the thickness of the prepreg is preferably 0.05–0.25 mm, more preferably 0.05–0.10 mm, further preferably 0.10–0.15 mm, even more preferably 0.15–0.25 mm, and most preferably 0.16 mm. By controlling the thickness of the prepreg, this invention helps improve the subsequent tiling effect.

[0039] In this invention, the temperature of the prepreg coating is preferably 20-30°C, more preferably 25°C.

[0040] In this invention, the method of applying the prepreg is preferably by laying it; the laying is preferably done by hand.

[0041] After obtaining the complex structure of the prepreg layer, the present invention coats the surface of the complex structure of the prepreg layer with a sealing material, then applies a vacuum and sequentially performs pressure holding and curing to obtain the complex structure of the bonding layer. In the present invention, the sealing material is preferably nylon or polyethylene.

[0042] In this invention, the target vacuum level of the vacuum pumping is preferably 1×10⁻⁶. -3 ~1×10 -5 Pa, more preferably 1×10 Pa -4 ~1×10 -5 Pa, more preferably 5 × 10 Pa -5 Pa. This invention ensures the bonding effect of the prepreg layer by controlling the vacuum level during vacuuming. Furthermore, the research revealed that excessively low vacuum levels lead to poor bonding of the prepreg layer; therefore, this invention employs the aforementioned vacuum level to guarantee the bonding performance of the prepreg layer.

[0043] In this invention, the vacuuming rate is preferably 1-5 liters / second, more preferably 2-4.5 liters / second, further preferably 2.5-4 liters / second, even more preferably 3-3.5 liters / second, and most preferably 3.22 liters / second. By controlling the vacuuming rate, this invention facilitates the slow release of air bubbles from the complex structure of the prepreg layer, avoiding the air bubble removal operations required by conventional physical methods. This not only avoids potential damage to the prepreg layer during physical air bubble removal but also improves the efficiency of air bubble removal, achieving a higher bubble removal rate, essentially removing all air bubbles, thereby improving the laying effect of the prepreg layer in complex structures.

[0044] In this invention, the pressure holding time is preferably 0.5–5 hours, more preferably 1–4.5 hours, further preferably 1.5–4 hours, even more preferably 2–3.5 hours, and most preferably 2.7 hours. This invention, through pressure holding, further ensures the bonding effect between the prepreg and the complex structure.

[0045] In the present application, the curing is preferably segmented curing; the segmented curing preferably comprises sequentially performing a first curing stage, a second curing stage and a third curing stage.

[0046] In the present application, the temperature of the first curing stage is preferably 80-110℃, more preferably 80-100℃, and the vacuum degree is preferably 1x10 -3 -5 Pa, and the curing time is preferably 0.5-3h, more preferably 1-2h, and further preferably 1.45h. -4 -5 Pa, and the curing time is preferably 0.5-3h, more preferably 1-2h, and further preferably 1.45h.

[0047] In the present application, the temperature of the second curing stage is preferably 120-280℃, more preferably 130-250℃, and further preferably 140-200℃, and the vacuum degree is preferably 1x10 -3 -5 Pa, and the curing time is preferably 0.5-3h, more preferably 1-2h, and further preferably 1.45h. -4 -5 Pa, and the curing time is preferably 0.5-3h, more preferably 1-2h, and further preferably 1.45h.

[0048] In the present application, the temperature of the third curing stage is preferably 150-380℃, more preferably 180-280℃, and the vacuum degree is preferably 1x10 -4 -5 Pa, and the curing time is preferably 0.5-3h, more preferably 1-2h, and further preferably 1.45h. -5 By the above curing, the present application is advantageous for full curing of the prepreg. Moreover, by the stepwise curing, the present application solves the problem of easy entry of gas between the layers of the conventional curing mode, improves the adhesion between the layers of the prepreg, and the overall paving effect is better. In addition, by the segmented curing, the present application ensures the curing effect while solving the problem of compatibility between the cured prepreg layer and the newly paved prepreg layer, thereby preventing the problem of delamination of each layer caused by the stepwise curing, and ensuring the overall performance of the composite material.

[0049] In the present application, the curing preferably further comprises cooling the obtained system, and the final temperature of the cooling is preferably 20-30℃, and more preferably 25℃.

[0050] ​​​​​After the complex structure of the laminated layer is obtained, the steps (1) and (2) are repeated on the surface of the complex structure of the laminated layer until the target thickness is reached. In the present application, the number of times of repeating the steps one and two (repeating the steps one and two once is recorded as 1 time) is preferably not more than 160 times, more preferably 10-140 times, further preferably 50-120 times, and more further preferably 80-100 times. By controlling the number of times of repeating, the present application prevents the problem of the laying effect being reduced in a fault-like manner due to too many times of laying.

[0051] In the present application, the target thickness is preferably not more than 8 mm, more preferably 1-4 mm, further preferably 1.5-3 mm, more further preferably 1.8-2.5 mm, and most preferably 2.1 mm. By controlling the overall thickness of the laying, the present application further ensures the laying effect.

[0052] In the present application, after the target thickness is reached, the obtained product is preferably trimmed. By trimming, the present application removes the excess composite material and other impurities such as burrs.

[0053] In order to further illustrate the present application, the schemes of the present application are described in detail below in conjunction with examples, but they should not be understood as limiting the scope of protection of the present application.

[0054] Example 1

[0055] The laying method of the complex structure of the composite material in the present example is as follows:

[0056] The epoxy resin prepreg with a thickness of 0.05 mm is laid on the surface of the complex structure at 25℃ to obtain a complex structure of prepreg layer; the closed nylon material is laid on the surface of the complex structure of prepreg layer, and then vacuum is extracted at a rate of 5 L / s to 1×10 -3 Pa, and then pressure is maintained for 3 h, 110℃, 1×10 -4 Pa for 0.5 h, 175℃, 1×10 -4 Pa for 5 h, 195℃, 1×10 -5 Pa for 0.5 h, the temperature is lowered to 25℃, the closed nylon material is removed, and a complex structure of laminated layer is obtained.

[0057] The above steps are repeated 22 times on the surface of the complex structure of the laminated layer, and finally the thickness of 1.1 mm is reached.

[0058] Example 2

[0059] The laying method of the complex structure of the composite material in the present example is as follows:

[0060] The epoxy resin prepreg with a thickness of 0.08 mm is laid on the surface of the complex structure at 25°C to obtain a prepreg layer complex structure; the sealing nylon material is laid on the surface of the prepreg layer complex structure, and then vacuum is drawn at a rate of 5 L / s to 1 x 10 -5 Pa, and then pressure is kept for 5 h, 80°C, 1 x 10 -5 Pa for 0.5 h, 120°C, 1 x 10 -5 Pa for 1 h, 180°C, 1 x 10 -5 Pa for 0.5 h, the temperature is lowered to 25°C, the sealing nylon material is removed, and a laminated layer complex structure is obtained.

[0061] The above steps are repeated 23 times on the surface of the laminated layer complex structure, and finally a thickness of 1.84 mm is reached.

[0062] Example 3

[0063] The laying method of the composite material complex structure in this example is as follows:

[0064] The epoxy resin prepreg with a thickness of 0.18 mm is laid on the surface of the complex structure at 25°C to obtain a prepreg layer complex structure; the sealing nylon material is laid on the surface of the prepreg layer complex structure, and then vacuum is drawn at a rate of 4 L / s to 1 x 10 -5 Pa, and then pressure is kept for 4.5 h, 125°C, 1 x 10 -5 Pa for 2 h, 155°C, 1 x 10 -5 Pa for 4 h, 175°C, 1 x 10 -5 Pa for 0.8 h, the temperature is lowered to 25°C, the sealing nylon material is removed, and a laminated layer complex structure is obtained.

[0065] The above steps are repeated 30 times on the surface of the laminated layer complex structure, and finally a thickness of 5.4 mm is reached.

[0066] Example 4

[0067] The laying method of the composite material complex structure in this example is as follows:

[0068] The epoxy resin prepreg with a thickness of 0.25 mm is laid on the surface of the complex structure at 25°C to obtain a prepreg layer complex structure; the sealing nylon material is laid on the surface of the prepreg layer complex structure, and then vacuum is drawn at a rate of 1 L / s to 1 x 10 -4 Pa, and then pressure is kept for 3 h, 100°C, 1 x 10 -4 Pa for 3 h, 130°C, 1 x 10 -4 Pa for 1 h, 150°C, 1 x 10 -5 Pa for 0.5 h, the temperature is lowered to 25°C, the sealing nylon material is removed, and a laminated layer complex structure is obtained.

[0069] The above step is repeated 18 times on the surface of the laminated layer complex structure, and finally a thickness of 4.5 mm is reached.

[0070] Example 5

[0071] The laminating method of the composite material complex structure in this example is as follows:

[0072] The double-male resin prepreg with a thickness of 0.06 mm is laminated on the surface of the complex structure at 25°C to obtain a prepreg layer complex structure; the sealing nylon material is laminated on the surface of the prepreg layer complex structure, and then vacuum is extracted at a rate of 2 L / s to 1 x 10 -3 Pa, and then pressure is maintained for 0.5 h, 100°C, 1 x 10 -4 Pa for 0.5 h, 150°C, 1 x 10 -3 Pa for 1 h, 250°C, 1 x 10 -5 Pa for 1 h, and the temperature is lowered to 25°C, the sealing nylon material is removed, and a laminated layer complex structure is obtained.

[0073] The above step is repeated 30 times on the surface of the laminated layer complex structure, and finally a thickness of 1.8 mm is reached.

[0074] Example 6

[0075] The laminating method of the composite material complex structure in this example is as follows:

[0076] The double-male resin prepreg with a thickness of 0.1 mm is laminated on the surface of the complex structure at 25°C to obtain a prepreg layer complex structure; the sealing nylon material is laminated on the surface of the prepreg layer complex structure, and then vacuum is extracted at a rate of 4 L / s to 1 x 10 -2 Pa, and then pressure is maintained for 2 h, 80°C, 1 x 10 -4 Pa for 2 h, 160°C, 1 x 10 -3 Pa for 3 h, 280°C, 1 x 10 -5 Pa for 0.6 h, and the temperature is lowered to 25°C, the sealing nylon material is removed, and a laminated layer complex structure is obtained.

[0077] The above step is repeated 53 times on the surface of the laminated layer complex structure, and finally a thickness of 5.3 mm is reached.

[0078] Example 7

[0079] The laminating method of the composite material complex structure in this example is as follows:

[0080] The double-male resin prepreg with a thickness of 0.16 mm is laminated on the surface of the complex structure at 25°C to obtain a prepreg layer complex structure; the sealing nylon material is laminated on the surface of the prepreg layer complex structure, and then vacuum is extracted at a rate of 3.5 L / s to 1 x 10 -4Pa, followed by 4.5 h of pressure holding, 180°C, 1 x 10 -3 Pa for 1.5 h, 135°C, 1 x 10 -3 Pa for 4 h, 260°C, 1 x 10 -5 Pa for 0.7 h, cooling to 25°C, and removing the sealing nylon material to obtain the laminated complex structure.

[0081] The above steps were repeated 38 times on the surface of the laminated complex structure until a target thickness of 6.08 mm was reached.

[0082] Example 8

[0083] The laminating method for the complex structure of the composite material of this example was as follows:

[0084] A polyimide resin prepreg with a thickness of 0.05 mm was laminated on the surface of the complex structure at 25°C to obtain a prepreg layer complex structure; a sealing nylon material was laminated on the surface of the prepreg layer complex structure, and then vacuum was drawn at a rate of 5 L / s to 1 x 10 -4 Pa, followed by 3 h of pressure holding, 110°C, 1 x 10 -4 Pa for 1 h, 350°C, 1 x 10 -4 Pa for 3 h, 300°C, 1 x 10 -5 Pa for 1 h, cooling to 25°C, and removing the sealing nylon material to obtain the laminated complex structure.

[0085] The above steps were repeated 40 times on the surface of the laminated complex structure until a target thickness of 2.0 mm was reached.

[0086] Example 9

[0087] The laminating method for the complex structure of the composite material of this example was as follows:

[0088] A polyimide resin prepreg with a thickness of 0.16 mm was laminated on the surface of the complex structure at 25°C to obtain a prepreg layer complex structure; a sealing nylon material was laminated on the surface of the prepreg layer complex structure, and then vacuum was drawn at a rate of 5 L / s to 1 x 10 -5 Pa, followed by 3.5 h of pressure holding, and removing the dense sealing material, 80°C, 1 x 10 -5 Pa for 3 h, 180°C, 1 x 10 -5 Pa for 5 h, 350°C, 1 x 10 -5 Pa for 2 h, cooling to 25°C, to obtain the laminated complex structure.

[0089] The above steps were repeated 22 times on the surface of the laminated complex structure until a target thickness of 3.52 mm was reached.

[0090] Example 10

[0091] The method for laying the composite material complex structure comprises the following specific steps:

[0092] Laying the epoxy resin prepreg with a thickness of 0.05 mm on the surface of the complex structure at 25 DEG C to obtain a prepreg layer complex structure; laying a closed nylon material on the surface of the prepreg layer complex structure, and then vacuumizing at a rate of 5 L / s to 1 x 10 -3 Pa, and then keeping pressure for 5 h, removing the dense closed material, curing at 100 DEG C, 1 x 10 -5 Pa for 3 h, curing at 130 DEG C, 1 x 10 -5 Pa for 5 h, and curing at 150 DEG C, 1 x 10 -5 Pa for 1 h, and cooling to 25 DEG C to obtain a laminated layer complex structure.

[0093] Repeating the above steps 48 times on the surface of the laminated layer complex structure until a target thickness of 2.4 mm is reached.

[0094] Comparative Example 1

[0095] The preparation method of the present comparative example is the same as that of Example 10, except that the segmented curing is replaced by constant temperature curing, curing at 100 DEG C, 1 x 10 -5 Pa for 3 h.

[0096] Comparative Example 2

[0097] The preparation method of the present comparative example is the same as that of Example 10, except that the segmented curing is replaced by two-stage curing, curing at 100 DEG C, 1 x 10 -5 Pa for 3 h, and curing at 130 DEG C, 1 x 10 -5 Pa for 5 h.

[0098] Comparative Example 3

[0099] The preparation method of the present comparative example is the same as that of Example 10, except that the segmented curing is replaced by constant temperature curing, curing at 150 DEG C, 1 x 10 -5 Pa for 1 h.

[0100] Comparative Example 4

[0101] The preparation method of the present comparative example is the same as that of Example 10, except that the vacuumizing is performed at a rate of 8 L / s.

[0102] Comparative Example 5

[0103] The preparation method of the present comparative example is the same as that of Example 10, except that the vacuumizing is performed at a rate of 0.2 L / s.

[0104] Comparative Example 6

[0105] The preparation method of the present comparative example is the same as that of example 10, except that the vacuum is drawn to 1x10 -2 Pa.

[0106] Comparative example 7

[0107] The preparation method of the present comparative example is the same as that of example 10, except that the vacuum is drawn for 0.1 h.

[0108] Test example 1

[0109] The complex structure of the composite material prepared in examples 1-10 and comparative examples 1-7 is detected for the lamination effect, the bubble ratio of the composite material is tested by the observation method, and the adhesion of the composite material is tested by the damp heat cycle method (70 DEG C, 95% humidity), and the results are shown in table 1.

[0110] Table 1 Lamination effect of examples 1-10 and comparative examples 1-7

[0111]

[0112]

[0113] According to table 1, the complex structure of the composite material laminated by the present application has good lamination effect, strong material adhesion performance, and ensures that the composite material can work normally.

[0114] From the above examples, it can be seen that the lamination method provided by the present application has simple steps, convenient operation, high feasibility, good lamination effect, and better material performance.

[0115] Although the above examples have described the present application in detail, it is only a part of the embodiments of the present application, not all the embodiments, and other embodiments can be obtained according to the present embodiment without creativity, which all belong to the protection scope of the present application.

[0116] The present application belongs to the technical field of composite material forming, and particularly relates to a segmented lamination curing forming method of a complex structure composite material. The lamination method provided by the present application is suitable for different complex structures, carries out corresponding segmented prepreg lamination according to different complex structures, has strong adaptability, good practical effect, optimizes the curing effect of deep composite material through step curing, better solves the lamination failure problem caused by poor lamination and curing effect of complex structure for a long time, has good comprehensive benefits, and has wide application prospect.

Claims

1. A method of segmented layup and cure forming of complex structures of composite materials, characterized in that, The method comprises the following steps: Step 1: covering prepreg on the surface of a complex structure to obtain a prepreg layer complex structure; Step 2: covering a dense sealing material on the surface of the prepreg layer complex structure, vacuumizing and then keeping pressure; Then curing after removing the dense sealing material to obtain a lamination layer complex structure; Step 3: repeating step 1 and step 2 on the surface of the lamination layer complex structure until the target thickness is reached to obtain a composite complex structure; The thickness of the prepreg is 0.05-0.25 mm; In step two, the target vacuum degree of the vacuumizing is 1x10 -3 ~1x10 -5 Pa; the time of the pressure maintaining is 0.5~5h; the rate of the vacuumizing is 2.5~4L / s; In step two, the curing is sectional curing; the sectional curing comprises sequentially performing a first curing section, a second curing section and a third curing section; the first curing section has a temperature of 80-110 ℃, a vacuum degree of 1x10 -3 ~1x10 -5 Pa, and a curing time of 0.5-3 h; the second curing section has a temperature of 120-280 ℃, a vacuum degree of 1x10 -3 ~1x10 -5 Pa, and a curing time of 1-5 h; and the third curing section has a temperature of 150-380 ℃, a vacuum degree of 1x10 -4 ~1x10 -5 Pa, and a curing time of 0.5-2 h. In step 3, the target thickness is not more than 8 mm.

2. The laying method according to claim 1, characterized in that In step 3, the number of times of repeating step 1 and step 2 is not more than 160.

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