Thermoplastic pre-impregnated fabric structure, method and apparatus for its preparation

Abstract

This invention discloses a thermoplastic prepreg fabric structure, its preparation method, and preparation apparatus. The thermoplastic prepreg fabric includes a first thermoplastic hot-melt porous mesh, a carbon fiber fabric with intermediate planar yarns, and a second thermoplastic hot-melt porous mesh, which are stacked sequentially. Both the first thermoplastic hot-melt porous mesh and the second thermoplastic hot-melt porous mesh include a carbon fiber fabric reinforcement structure and a thermoplastic resin prepreg structure.

Description

Technical Field

[0001] This invention belongs to the field of prepreg fabric preparation technology, specifically relating to a thermoplastic prepreg fabric structure, its preparation method and preparation apparatus. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Thermosetting carbon fiber composites are currently the main products of carbon fiber reinforced resin matrix composites. Their excellent mechanical properties and low density make them the most promising alternative raw materials for improving the performance of metal structural components. However, due to the special molecular cross-linking structure of thermosetting resins after curing, they have macroscopic physical properties of being infusible and insoluble. This also brings about the problems of non-recyclability and inability to be repeatedly molded and processed in composites based on them. In order to optimize the recyclability of carbon fiber composites, carbon fiber composites based on thermoplastic resins have become a key research direction for new composite materials.

[0004] However, thermoplastic resins have high hot melt viscosity, which directly results in very low melt flowability, making it difficult to directly impregnate and prepare thermoplastic composites. At the same time, solvent liquid phase treatment technology for thermoplastic resins brings technical problems such as difficulty in solvent removal, which easily leads to large porosity, poor density, and poor mechanical properties of thermoplastic composites. Summary of the Invention

[0005] In order to solve the technical problems existing in the prior art, the purpose of this invention is to provide a thermoplastic prepreg fabric structure, its preparation method and preparation apparatus.

[0006] To achieve the above-mentioned objectives, one or more embodiments of the present invention disclose the following technical solutions:

[0007] In a first aspect, a thermoplastic prepreg fabric is provided, comprising a first thermoplastic hot-melt porous mesh, a central planar yarn carbon fiber fabric, and a second thermoplastic hot-melt porous mesh, which are sequentially stacked.

[0008] Both the first thermoplastic hot-melt porous mesh and the second thermoplastic hot-melt porous mesh include a carbon fiber fabric reinforcement structure and a thermoplastic resin prepreg structure.

[0009] Secondly, a method for preparing the thermoplastic prepreg fabric is provided, comprising the following steps:

[0010] The reinforcing fiber fabric is continuously fed into a vacuum impregnation device, sealed, and then a vacuum is drawn.

[0011] Once the vacuum level in the vacuum impregnation device reaches the standard, glue is simultaneously injected onto the upper and lower surfaces of the reinforcing fiber fabric for vacuum impregnation, while simultaneously undergoing heating and melting treatment.

[0012] The prepreg fabric is pulled out of the vacuum impregnation device and then subjected to hot-melt pressure impregnation by an electrically heated roller device to obtain thermoplastic prepreg fabric.

[0013] Thirdly, an apparatus for preparing the thermoplastic prepreg fabric is provided, comprising: a semi-enclosed vacuum impregnation apparatus and an electrically heated roller, wherein the electrically heated roller is disposed downstream of the semi-enclosed vacuum impregnation apparatus;

[0014] The semi-enclosed vacuum impregnation device provides a semi-enclosed impregnation chamber, a vacuum pumping device, and a glue injection device. An inlet channel and an outlet channel are respectively provided on opposite sides of the semi-enclosed impregnation chamber, and a sealing device is provided at both the inlet channel and the outlet channel.

[0015] The vacuum pump is connected to the semi-enclosed impregnation chamber;

[0016] The glue injection head of the glue injection device is located in a semi-enclosed impregnation chamber. It consists of two layers, upper and lower, distributed on both sides of the fiber fabric channel, with the glue injection directions of the upper and lower layers of glue injection heads facing each other.

[0017] Compared with the prior art, one or more technical solutions of the present invention have achieved the following beneficial effects:

[0018] In the prepreg fabric prepared by vacuum hot melt impregnation and roller hot melt pressure impregnation, the prepreg hot melt resin can be distributed relatively evenly on the upper and lower surfaces of the prepreg fabric. When using the prepreg fabric to prepare composite materials, it is only necessary to use hot melt pressure impregnation and other treatment methods to prepare carbon fiber composite materials with thermoplastic resin as the matrix that are uniformly impregnated.

[0019] When using this method, the resin is heated and melted before being directly impregnated, without the involvement of solvent, thus effectively solving the problem of solvent removal. Attached Figure Description

[0020] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0021] Figure 1 This is a schematic diagram of the pre-set structure of the thermoplastic carbon fiber prepreg fabric produced by the two-step method of this invention.

[0022] Figure 2 This is a schematic diagram of the structure of a production apparatus for producing thermoplastic carbon fiber prepreg fabrics using a two-step method according to an embodiment of the present invention.

[0023] The components include: 1. a layer of dry carbon fiber yarn fabric to be impregnated; 2. a first thermoplastic hot melt porous mesh; 3. a second thermoplastic hot melt porous mesh; 4. an end-sealing device; 5. a vacuuming device; 6. an electrically heated roller; 7. a glue-injecting device; and 8. a semi-enclosed vacuum impregnation device. Detailed Implementation

[0024] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0025] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0026] In a first aspect, a thermoplastic prepreg fabric is provided, comprising a first thermoplastic hot-melt porous mesh, a central planar yarn carbon fiber fabric, and a second thermoplastic hot-melt porous mesh, which are sequentially stacked.

[0027] Both the first thermoplastic hot-melt porous mesh and the second thermoplastic hot-melt porous mesh include a carbon fiber fabric reinforcement structure and a thermoplastic resin prepreg structure.

[0028] In some embodiments, the yarn of the intermediate planar yarn carbon fiber fabric is selected from one of T300, T700, T800, and T1000 carbon fibers.

[0029] Furthermore, the structure of the intermediate planar yarn carbon fiber fabric can be any one of a unidirectional fabric or a two-dimensional fabric of plain weave, twill weave, or satin weave.

[0030] In some embodiments, the material of the thermoplastic resin prepreg structure is selected from any one of polyethylene (PE), polypropylene (PP), polybutylene terephthalate (PBT), polyamide (PA), polyphenylene sulfide (PPS), polyetherimide (PEI), polyether ketone ketone (PEKK), polyether ether ketone (PEEK), and polyoxymethylene (POM).

[0031] Furthermore, the basis weight of the first and second thermoplastic hot-melt porous membranes is controlled at 5-50 g / m². 2 For example, it could be 5g / m³. 2 10g / m 2 15g / m 2 20g / m2 25g / m 2 30g / m 2 35g / m 2 40g / m 2 45g / m 2 50g / m 2 .

[0032] Thermoplastic hot melt porous membrane is prepared by melt spinning of ultrafine fibers. The fibers have a porous structure, so the prepared membrane is a porous membrane.

[0033] Secondly, a method for preparing the thermoplastic prepreg fabric is provided, comprising the following steps:

[0034] The reinforcing fiber fabric is continuously fed into a vacuum impregnation device, sealed, and then a vacuum is drawn.

[0035] Once the vacuum level in the vacuum impregnation device reaches the standard, glue is simultaneously injected onto the upper and lower surfaces of the reinforcing fiber fabric for vacuum impregnation, while simultaneously undergoing heating and melting treatment.

[0036] The prepreg fabric is pulled out of the vacuum impregnation device and then subjected to hot-melt pressure impregnation by an electrically heated roller device to obtain thermoplastic prepreg fabric.

[0037] Vacuum impregnation can improve the impregnation penetration effect.

[0038] In some embodiments, the vacuum level after achieving the standard is 0.06-0.1 MPa.

[0039] In some embodiments, the thermoplastic prepreg fabric has a glue content of 40-70%, where % is a mass percentage.

[0040] In some embodiments, the heating and melting temperature is 120-300°C.

[0041] Furthermore, the heating and melting time is 5-20 minutes.

[0042] In some embodiments, the temperature at which the electrically heated roller device performs hot-melt pressure impregnation is 120-300°C.

[0043] Furthermore, the pressure used for hot-melt pressurized impregnation by the electrically heated roller device is 1-5 MPa. For example, 1 MPa, 2 MPa, 3 MPa, 4 MPa, 5 MPa.

[0044] Furthermore, the rotational speed of the electrically heated roller device is 2-10 meters per minute.

[0045] Thirdly, an apparatus for preparing the thermoplastic prepreg fabric is provided, comprising: a semi-enclosed vacuum impregnation apparatus and an electrically heated roller, wherein the electrically heated roller is disposed downstream of the semi-enclosed vacuum impregnation apparatus;

[0046] The semi-enclosed vacuum impregnation device provides a semi-enclosed impregnation chamber, a vacuum pumping device, and a glue injection device. An inlet channel and an outlet channel are respectively provided on opposite sides of the semi-enclosed impregnation chamber, and a sealing device is provided at both the inlet channel and the outlet channel.

[0047] The vacuum pump is connected to the semi-enclosed impregnation chamber;

[0048] The glue injection head of the glue injection device is located in a semi-enclosed impregnation chamber. It consists of two layers, upper and lower, distributed on both sides of the fiber fabric channel, with the glue injection directions of the upper and lower layers of glue injection heads facing each other.

[0049] The sealing device is a movable sealing plate. Both sides of the sealing device consist of upper and lower parts. The lower part is fixed, while the upper part can move up and down. The sealing plate is sealed to the semi-enclosed impregnation chamber body. The driving force for the up and down movement is driven by a motor, and the upper and lower parts are sealed with a sealing strip. To reduce the impact on the fabric, the sealing plate has a small thickness.

[0050] Example 1

[0051] The specific implementation method of this embodiment for producing thermoplastic carbon fiber prepreg fabric in a two-step process and the structure of the prepreg fabric are as follows:

[0052] The composite design structure of the prepreg fabric was determined, with the intermediate reinforcing fabric having a weight of 100 g / m². 2 A unidirectional planar fabric of T300 carbon fiber, with layers of 50 g / m² stacked on the upper and lower surfaces of the planar fabric. 2 Polyethylene (PE) and thermoplastic resin mesh.

[0053] The entire process of preparing the composite prepreg fabric begins by placing the prepreg structure as described above into a semi-closed vacuum impregnation equipment using a conventional device. Then, the two ends are sealed using a sealing device. After the vacuum pretreatment of the impregnation equipment is activated and the vacuum level is controlled at 0.1 MPa, CBT vacuum injection thermoplastic resin is injected into the prepreg structure as described above under vacuum conditions through an injection system. The final resin content is 20%. After that, the hot melt heating is activated and the first heating impregnation composite is carried out at 120°C for 5 minutes.

[0054] The pre-impregnated composite structure is then pulled out of the semi-enclosed vacuum impregnation equipment under the drive of the force-driven yarn system, and enters a counter-rotating electrically heated roller device for pneumatic pressurization. The entire rotation speed is 2 meters / minute. During the continuous transmission process, the composite structure undergoes a secondary hot-melt bonding process at 180°C and 1 MPa pressure. The final resin content of the pre-impregnated fabric is 45%. This process ultimately forms a two-step thermoplastic resin impregnation process: interfacial vacuum hot-melt impregnation and pressurized hot-melt impregnation, completing the pre-impregnated fabric processing.

[0055] Example 2

[0056] The present invention discloses a two-step process for producing thermoplastic carbon fiber prepreg fabric and a prepreg fabric structure, the specific implementation of which is as follows:

[0057] The composite design structure of the prepreg fabric was determined, with the intermediate reinforcing fabric having a weight of 150 g / m². 2 T700 carbon fiber plain weave planar fabric, with layers of 10 g / m² on the upper and lower surfaces of the planar fabric. 2 Polyphenylene sulfide (PPS) thermoplastic resin web film.

[0058] The entire process of preparing the composite prepreg fabric begins by placing the prepreg structure as described above into a semi-closed vacuum impregnation equipment using conventional equipment. Then, the two ends are sealed using a sealing device. After the vacuum pretreatment of the impregnation equipment is activated and the vacuum level is controlled at 0.1 MPa, a low-viscosity thermoplastic resin emulsion of polyphenylene sulfide (PPS) is injected into the prepreg structure as described above under vacuum conditions through a glue injection system. The final resin content is 20%. Then, the hot melt heating is activated and the first heating impregnation composite is carried out at 150°C for 10 minutes.

[0059] The pre-impregnated composite structure is then pulled out of the semi-enclosed vacuum impregnation equipment under the drive of the force-driven yarn system, and enters a counter-rotating electrically heated roller device for pneumatic pressurization. The entire rotation speed is 3 meters per minute. During continuous transmission, the composite structure undergoes a secondary hot-melt bonding process at 190°C and 2 MPa pressure. The final pre-impregnated fabric has a resin content of 50%. This process ultimately forms a two-step thermoplastic resin impregnation process: interface vacuum hot-melt impregnation and pressurized hot-melt impregnation, completing the pre-impregnated fabric processing.

[0060] Example 3

[0061] The present invention discloses a two-step process for producing thermoplastic carbon fiber prepreg fabric and a prepreg fabric structure, the specific implementation of which is as follows:

[0062] The composite design structure of the prepreg fabric was determined, with the intermediate reinforcing fabric having a basis weight of 180 g / m². 2 T1000 carbon fiber satin-weave flat fabric, with layers of 20 g / m² on the upper and lower surfaces of the flat fabric. 2Polybutylene terephthalate (PBT) thermoplastic resin web.

[0063] The entire process of preparing the composite prepreg fabric begins by placing the prepreg structure as described above into a semi-closed vacuum impregnation equipment using conventional equipment. Then, the two ends are sealed using a sealing device. After the vacuum pretreatment of the impregnation equipment is activated and the vacuum level is controlled at 0.09 MPa, the thermoplastic hot melt adhesive of polybutylene terephthalate (PBT) is injected into the prepreg structure as described above under vacuum conditions through the glue injection system. The final resin content is 25%. Then, the hot melt heating is activated and the first heating impregnation composite is carried out at 130°C for 12 minutes.

[0064] The pre-impregnated composite structure is then pulled out of the semi-enclosed vacuum impregnation equipment under the drive of the force-driven yarn system, and enters a counter-rotating electrically heated roller device for pneumatic pressurization. The entire rotation speed is 4 meters per minute. During the continuous transmission process, the composite structure undergoes a secondary hot-melt bonding process at 280°C and 3MPa pressure. The final pre-impregnated fabric has a resin content of 60%. This process ultimately forms a two-step thermoplastic resin impregnation process: interfacial vacuum hot-melt impregnation and pressurized hot-melt impregnation, completing the pre-impregnated fabric processing.

[0065] Example 4

[0066] The present invention discloses a two-step process for producing thermoplastic carbon fiber prepreg fabric and a prepreg fabric structure, the specific implementation of which is as follows:

[0067] The composite design structure of the prepreg fabric was determined, with the intermediate reinforcing fabric having a basis weight of 190 g / m². 2 T800 carbon fiber twill weave planar fabric, with layers of 40 g / m² on the upper and lower surfaces of the planar fabric. 2 Polyamide (PA) thermoplastic resin web film.

[0068] The entire process of preparing the composite prepreg fabric begins by placing the prepreg structure as described above into a semi-closed vacuum impregnation equipment using conventional equipment. Then, the two ends are sealed using a sealing device. After the vacuum pretreatment of the impregnation equipment is started and the vacuum level is controlled at 0.08 MPa, a low-viscosity thermoplastic resin emulsion of polyamide (PA) is injected into the prepreg structure as described above under vacuum conditions through a glue injection system. The final resin content is 30%. Then, the hot melt heating is started and the first heating impregnation composite is carried out at 190°C for 12 minutes.

[0069] The pre-impregnated composite structure is then pulled out of the semi-enclosed vacuum impregnation equipment under the drive of the force-driven yarn system, and enters a counter-rotating electrically heated roller device for pneumatic pressurization. The entire rotation speed is 5 meters per minute. During continuous transmission, the composite structure undergoes a secondary hot-melt bonding process at 260°C and 4 MPa pressure. The final pre-impregnated fabric has a resin content of 50%. This process ultimately forms a two-step thermoplastic resin impregnation process: interfacial vacuum hot-melt impregnation and pressurized hot-melt impregnation, completing the pre-impregnated fabric processing.

[0070] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a thermoplastic prepreg fabric, characterized in that, Includes the following steps: The first thermoplastic hot-melt porous mesh, the intermediate planar yarn carbon fiber fabric, and the second thermoplastic hot-melt porous mesh, which are stacked in sequence, are put into a vacuum impregnation device, sealed, and then a vacuum is drawn; the vacuum degree after reaching the standard is 0.06-0.1MPa. Once the vacuum level in the vacuum impregnation device reaches the required standard, glue is simultaneously injected onto the upper and lower surfaces of the reinforcing fiber fabric for vacuum impregnation, while a heating and melting treatment is performed simultaneously. The heating and melting temperature is 120-300℃, and the heating and melting time is 5-20 minutes. The treated prepreg fabric is pulled out of the vacuum impregnation device and subjected to hot-melt pressure impregnation by an electrically heated roller device; thus, thermoplastic prepreg fabric is obtained. The temperature at which the electrically heated roller device performs hot-melt pressure impregnation is 120-300℃; The thermoplastic prepreg fabric has a glue content of 40-70%, where % is a mass percentage; The pressure of the electric heating roller device for hot melting and pressurized impregnation is 1-5 MPa; Thermoplastic hot-melt porous mesh is prepared by melt spinning of ultrafine fibers. The fibers have a porous structure, so the prepared mesh is a porous mesh. The material of the prepreg structure in the thermoplastic prepreg fabric is selected from any one of polyethylene, polypropylene, polybutylene terephthalate, polyamide, polyphenylene sulfide, polyetherimide, polyetherketoneketone, polyetheretherketone, and polyoxymethylene. When the prepreg structure is made of polyethylene, the resin content for injection molding is 20%. When the prepreg material is polyphenylene sulfide, the resin content of the injection molding compound is 20%. When the prepreg material is polybutylene terephthalate, the resin content of the injection molding compound is 25%. When the prepreg material is polyamide, the resin content of the injection molding is 30%.

2. The thermoplastic prepreg fabric as described in claim 1, characterized in that, The rotational speed of the electrically heated roller device is 2-10 meters per minute.

3. The thermoplastic prepreg fabric as described in claim 1, characterized in that, The yarn of the reinforcing fiber fabric is selected from one of T300, T700, T800, and T1000 carbon fibers.

4. The thermoplastic prepreg fabric as described in claim 1, characterized in that, The structure of the reinforcing fiber fabric can be any one of unidirectional fabric or plain weave, twill weave, or satin weave two-dimensional fabric.

5. The thermoplastic prepreg fabric as described in claim 1, characterized in that, The basis weight of the upper and lower layers of the thermoplastic prepreg fabric is controlled at 5-50 g / m². 2 .

6. The apparatus used for preparing the thermoplastic prepreg fabric according to any one of claims 1-5, characterized in that: include: A semi-enclosed vacuum impregnation device and an electrically heated roller, wherein the electrically heated roller is located downstream of the semi-enclosed vacuum impregnation device; The semi-enclosed vacuum impregnation device provides a semi-enclosed impregnation chamber, a vacuum pumping device, and a glue injection device. An inlet channel and an outlet channel are respectively provided on opposite sides of the semi-enclosed impregnation chamber, and a sealing device is provided at both the inlet channel and the outlet channel. The vacuum pump is connected to the semi-enclosed impregnation chamber; The glue injection head of the glue injection device is located in a semi-enclosed impregnation chamber. It consists of two layers, upper and lower, distributed on both sides of the fiber fabric channel, with the glue injection directions of the upper and lower layers of glue injection heads facing each other.

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