Improved two-dimensional PET + CFRT prepreg preparation method based on special-shaped PET base material

Abstract

The invention discloses a preparation method of improved two-dimensional PET + CFRT prepreg based on a special-shaped PET base material, and belongs to the technical field of composite material preparation. The preparation method comprises the following steps: spraying a pretreatment solution on the surface of the continuous fiber CFRT, and carrying out braising treatment on the continuous fiber CFRT in an environment with the temperature of 65-70 DEG C and the relative humidity of 80-85% for 12-18 hours; cleaning and drying the pretreated continuous fiber CFRT, then conducting filament guiding, and under the condition of reduced pressure, conducting dipping treatment in PET melt liquid to obtain PET + CFRT prepreg; slitting the PET + CFRT prepreg into a prepreg tape with the standard width of 6.35 mm, which is used by an automatic fiber placement machine, by adopting an automatic prepreg slitting machine; the preparation method comprises the following steps: preparing a prepreg tape, automatically laying the prepreg tape by adopting an automatic fiber laying machine to generate a PET + CFRT prefabricated body, cutting the PET + CFRT prefabricated body, sequentially carrying out drying and hot pressing treatment on the cut PET + CFRT prefabricated body for curing, and respectively compounding the upper surface and the lower surface of the cured PET + CFRT prefabricated body by adopting a release film and release paper to obtain the two-dimensional PET + CFRT prepreg cloth. The preparation and research blank of the two-dimensional PET + CFRT prepreg cloth is filled up.

Description

Technical Field

[0001] The invention relates to a method for preparing an improved two-dimensional PET+CFRT prepreg based on a special-shaped PET substrate, and belongs to the technical field of composite material preparation. Background Art

[0002] Advanced composite materials have the advantages of light weight, high specific strength, high wear resistance, fatigue resistance, and good molding process. They have been widely used in the fields of ships, rail vehicles, new energy vehicles, etc., especially in the field of ships. The extensive use of composite materials can not only reduce the weight of the ship, reduce fuel consumption and increase the speed, but also reduce maintenance costs and extend the service life of the ship.

[0003] PET foam, the main component is polyethylene terephthalate (Polyethylene terephthalate), commonly known as polyester resin. Polyethylene terephthalate (polyester resin) is mainly used to make synthetic fibers, films, bottles, and is also used in engineering plastics and other fields. When it is foamed, the PET foam material formed is relatively brittle, but it has good heat resistance and mechanical strength. PET foam can be recycled, so it has good environmental performance.

[0004] CFRT, or continuous fiber reinforced thermoplastic composites, is widely used in many industries due to its high strength and low density. Existing PET+CFRT composites are mostly made by simple hot pressing, and there is a lack of research on the preparation of composite prepreg tapes for special-shaped PET substrates. Summary of the invention

[0005] The purpose of the present invention is to overcome the technical defects of the prior art, solve the above-mentioned technical problems, and propose an improved two-dimensional PET+CFRT prepreg preparation method based on a special-shaped PET substrate.

[0006] The present invention specifically adopts the following technical solution: an improved two-dimensional PET+CFRT prepreg preparation method based on a special-shaped PET substrate, characterized in that it comprises the following steps:

[0007] Step SS1: pre-treating the continuous fiber CFRT, including: spraying a pre-treatment liquid on the surface of the continuous fiber CFRT, and subjecting the continuous fiber CFRT to a suffocating treatment at 65-70° C. and 80-85% relative humidity for 12-18 hours;

[0008] Step SS2: impregnation treatment, including: washing and drying the pretreated continuous fiber CFRT, and then impregnating it in a PET melt under reduced pressure after passing through the guide wire to obtain a PET+CFRT prepreg;

[0009] Step SS3: Prepreg tape preparation, including: using an automatic prepreg slitting machine to slit the PET+CFRT prepreg into prepreg tapes with a standard width of 6.35 mm used by an automatic fiber placement machine;

[0010] Step SS4: The prepreg tape is automatically laid out by an automatic wire laying machine to generate a PET+CFRT preform, the PET+CFRT preform is cut, and the cut PET+CFRT preform is sequentially dried and hot-pressed to be cured, and the upper and lower surfaces of the cured PET+CFRT preform are respectively compounded with a release film and a release paper to obtain a two-dimensional PET+CFRT prepreg cloth.

[0011] As a preferred embodiment, the temperature of the PET melt in step SS2 is 280-300°C.

[0012] As a preferred embodiment, the hot pressing treatment for curing in step SS4 includes: curing in an autoclave, with a curing temperature of 185 to 220° C., a curing time of 7 to 9 hours, and a curing pressure of 1.2 to 2.0 MPa.

[0013] As a preferred embodiment, in step SS4, the automatic fiber placement machine is used to automatically place the prepreg tape to generate the PET+CFRT preform, which specifically includes:

[0014] Step SS41: Select the minimum square size for preparing the two-dimensional PET+CFRT prepreg, and lay the single-sided adhesive polytetrafluoroethylene cloth on the surface of the corresponding square area on the laying platform;

[0015] Step SS42: At the four vertex corners of the square area, the "laying straight track" function of the automatic wire laying machine is used. The automatic wire laying machine lays a prepreg tape in sequence at the layer design angles α, β, γ, and δ respectively. One side of the prepreg tape just presses the vertex, and the other side is located in the square area. The laying positions of α, β, γ, and δ are determined according to their angles. Among them, the upper left vertex corner of the square area lays a prepreg tape with a design angle of 0°, the upper right vertex corner lays a prepreg tape with a design angle of 0° to 90°, the lower left vertex corner lays a prepreg tape with a design angle of 90°, and the lower right vertex corner lays a prepreg tape with a design angle of -90° to 0°;

[0016] Step SS43: the automatic fiber placement machine continues to lay down a prepreg tape in the square area in the order of angles α→β→γ→δ, wherein the center line of the next prepreg tape is spaced apart from the center line of the previous prepreg tape by ai, where ai=6.35n, n is an integer, and i corresponds to α, β, γ, and δ respectively;

[0017] Step SS44: the automatic fiber placement machine places the next prepreg tape in the order of α→β→γ→δ from the center line position of the previous prepreg tape corresponding to the same design angle in the previous round into the working area at a certain distance ai;

[0018] Step SS45: repeat step SS44 until the centerline position of the prepreg tape corresponding to the next interval ai falls outside the square area, skip the design angle, and continue to lay the prepreg tape corresponding to the next design angle until the centerline positions of all prepreg tapes corresponding to the next interval ai fall outside the square area, and stop laying;

[0019] Step SS46: The automatic fiber placement machine places a prepreg tape in the order of α→β→γ→δ from the center line position of the first prepreg tape corresponding to the same design angle into the working area, and places the next prepreg tape only next to the first prepreg tape. The distance between the center lines of the two adjacent prepreg tapes is 6.35 mm, and a new round of fiber placement begins;

[0020] Step SS47: The automatic fiber placement machine places the next prepreg tape at a certain distance ai from the center line position of the previous prepreg tape corresponding to the same design angle in the previous round into the working area in the order of α→β→γ→δ;

[0021] Step SS48: Repeat the steps of SS47 until the centerline position of the prepreg tape corresponding to the next interval ai falls outside the square area, skip the design angle, and continue to lay the prepreg tape corresponding to the next design angle until the centerline positions of all prepreg tapes corresponding to the next interval ai fall outside the square area, completing the laying of this round of prepreg tapes;

[0022] Step SS49: The automatic wire placing machine follows the laying order of α→β→γ→δ, starting from the first prepreg tape corresponding to the same design angle in the previous round, repeats steps SS46 to SS48, and starts another round of wire placing until the prepreg tapes with the same design angle fill the square area, skips the design angle, and continues with the next round of wire placing until all prepreg tapes with the same design angle fill the square area, completing the automatic laying of all prepreg tapes to obtain an automatically placed PET+CFRT preform.

[0023] As a preferred embodiment, the cutting of the PET+CFRT preform in step SS4 includes: cutting the PET+CFRT preform along the boundary line of the square area, and compounding the upper and lower surfaces of the cut PET+CFRT preform with release film and release paper respectively to obtain a two-dimensional PET+CFRT prepreg.

[0024] As a preferred embodiment, the PET is polyethylene terephthalate.

[0025] As a preferred embodiment, the moving speed of the continuous fiber CFRT during the impregnation process is 12-20 m / min.

[0026] As a preferred embodiment, the pretreatment liquid is prepared from the following components in percentage by mass: 5-6% hydrophilic amino silicone oil, 1-3% sodium dodecylbenzene sulfonate, 2-3% sodium chloride and the balance water.

[0027] As a preferred embodiment, the prepreg tape has a thickness of 0.5-0.8 mm and a width of 100-800 mm.

[0028] As a preferred embodiment, the mass content of the continuous fiber CFRT in the prepreg tape is 46-48%.

[0029] Beneficial effects achieved by the present invention: The present invention aims to solve the technical demand for research on the preparation of composite prepreg tapes for special-shaped PET substrates, which are mostly made by simple hot pressing molding in existing PET+CFRT composite materials. The improved two-dimensional PET+CFRT prepreg cloth preparation method based on special-shaped PET substrates includes the following steps: Step SS1: pretreating continuous fiber CFRT, including: spraying pretreatment liquid on the surface of continuous fiber CFRT, and suffocating the continuous fiber CFRT in an environment of 65-70°C and 80-85% relative humidity for 12-18h; Step SS2: impregnation treatment, including: cleaning and drying the pretreated continuous fiber CFRT, and then impregnating it in PET melt under reduced pressure after passing through a guide wire to obtain PET+CFRT prepreg; the temperature of the PET melt in step SS2 is 280°C; Step SS3: prepreg The tape preparation comprises: using an automatic prepreg slitting machine to slit a PET+CFRT prepreg into a prepreg tape with a standard width of 6.35 mm used by an automatic wire laying machine; step SS4: using an automatic wire laying machine to automatically lay the prepreg tape to generate a PET+CFRT preform, cutting the PET+CFRT preform, drying and hot pressing the cut PET+CFRT preform in sequence for curing, and compounding the upper and lower surfaces of the cured PET+CFRT preform with a release film and a release paper respectively to obtain a two-dimensional PET+CFRT prepreg cloth. The two-dimensional PET+CFRT prepreg cloth can be widely used in the fields of ships, rail vehicles, new energy vehicles, etc., especially in the field of weight reduction design of ship parts. The large-scale use of two-dimensional PET+CFRT prepreg cloth to prepare parts can not only reduce the weight of the ship, reduce fuel consumption and increase the speed, but also reduce maintenance costs and extend the service life of the ship. DETAILED DESCRIPTION

[0030] The present invention is further described below. The following examples are only used to more clearly illustrate the technical solution of the present invention, and are not intended to limit the protection scope of the present invention.

[0031] Embodiment 1: A method for preparing an improved two-dimensional PET+CFRT prepreg based on a special-shaped PET substrate, characterized in that it comprises the following steps:

[0032] Step SS1: pre-treating the continuous fiber CFRT, including: spraying a pre-treatment liquid on the surface of the continuous fiber CFRT, and subjecting the continuous fiber CFRT to a suffocating treatment at 65-70° C. and 80-85% relative humidity for 12-18 hours;

[0033] Step SS2: impregnation treatment, including: washing and drying the pretreated continuous fiber CFRT, and then impregnating it in a PET melt under reduced pressure after passing through the guide wire to obtain a PET+CFRT prepreg; the temperature of the PET melt in step SS2 is 280° C.;

[0034] Step SS3: Prepreg tape preparation, including: using an automatic prepreg slitting machine to slit the PET+CFRT prepreg into prepreg tapes with a standard width of 6.35 mm used by an automatic fiber placement machine;

[0035] Step SS4: The prepreg tape is automatically laid out by an automatic wire laying machine to generate a PET+CFRT preform, the PET+CFRT preform is cut, and the cut PET+CFRT preform is sequentially dried and hot-pressed to be cured, and the upper and lower surfaces of the cured PET+CFRT preform are respectively compounded with a release film and a release paper to obtain a two-dimensional PET+CFRT prepreg cloth.

[0036] The hot pressing treatment for curing in step SS4 includes: curing in an autoclave, with a curing temperature of 185 to 220° C., a curing time of 7 to 9 hours, and a curing pressure of 1.2 to 2.0 MPa.

[0037] In step SS4, the prepreg tape is automatically laid by an automatic wire laying machine to generate a PET+CFRT preform, which specifically includes:

[0038] Step SS41: Select the minimum square size for preparing the two-dimensional PET+CFRT prepreg, and lay the single-sided adhesive polytetrafluoroethylene cloth on the surface of the corresponding square area on the laying platform;

[0039] Step SS42: At the four corners of the square area, the automatic wire laying machine's "laying straight track" function is used. The automatic wire laying machine lays a prepreg tape in sequence at the design laying angles α, β, γ, and δ respectively. One side of the prepreg tape just presses the corner, and the other side is located in the square area. The laying positions of α, β, γ, and δ are determined according to their angles. Among them, the upper left corner of the square area lays a prepreg tape with a design angle of 0°, the upper right corner lays a prepreg tape with a design angle of 0° to 90°, the lower left corner lays a prepreg tape with a design angle of 90°, and the lower right corner lays a prepreg tape with a design angle of -90° to 0°;

[0040] Step SS43: the automatic fiber placement machine continues to lay down a prepreg tape in the square area in the order of angles α→β→γ→δ, wherein the center line of the next prepreg tape is spaced apart from the center line of the previous prepreg tape by ai, where ai=6.35n, n is an integer, and i corresponds to α, β, γ, and δ respectively;

[0041] Step SS44: the automatic fiber placement machine places the next prepreg tape in the order of α→β→γ→δ from the center line position of the previous prepreg tape corresponding to the same design angle in the previous round into the working area at a certain distance ai;

[0042] Step SS45: repeat step SS44 until the centerline position of the prepreg tape corresponding to the next interval ai falls outside the square area, skip the design angle, and continue to lay the prepreg tape corresponding to the next design angle until the centerline positions of all prepreg tapes corresponding to the next interval ai fall outside the square area, and stop laying;

[0043] Step SS46: The automatic fiber placement machine places a prepreg tape in the order of α→β→γ→δ from the center line position of the first prepreg tape corresponding to the same design angle into the working area, and places the next prepreg tape only next to the first prepreg tape. The distance between the center lines of the two adjacent prepreg tapes is 6.35 mm, and a new round of fiber placement begins;

[0044] Step SS47: The automatic fiber placement machine places the next prepreg tape at a certain distance ai from the center line position of the previous prepreg tape corresponding to the same design angle in the previous round into the working area in the order of α→β→γ→δ;

[0045] Step SS48: Repeat the steps of SS47 until the centerline position of the prepreg tape corresponding to the next interval ai falls outside the square area, skip the design angle, and continue to lay the prepreg tape corresponding to the next design angle until the centerline positions of all prepreg tapes corresponding to the next interval ai fall outside the square area, completing the laying of this round of prepreg tapes;

[0046] Step SS49: The automatic wire laying machine starts from the first prepreg tape corresponding to the same design angle in the previous round in the laying order of α→β→γ→δ, repeats steps SS46 to SS48, and starts another round of wire laying until the prepreg tapes with the same design angle fill the square area, skips the design angle, and continues the next round of wire laying until all prepreg tapes with the same design angle fill the square area, completes the automatic laying of all prepreg tapes, and obtains an automatic wire laying PET+CFRT preform. The PET+CFRT preform cutting in step SS4 includes: cutting the PET+CFRT preform along the boundary line of the square area, and the upper and lower surfaces of the cut PET+CFRT preform are respectively compounded with release film and release paper to obtain a two-dimensional PET+CFRT prepreg cloth. The PET is polyethylene terephthalate. The moving speed of the continuous fiber CFRT during the impregnation process is 12-20m / min. The pretreatment liquid is prepared from the following components in mass percentage: 5-6% hydrophilic amino silicone oil, 1-3% sodium dodecylbenzene sulfonate, 2-3% sodium chloride and the balance water. The thickness of the prepreg tape is 0.5-0.8mm and the width is 100-800mm. The mass content of continuous fiber CFRT in the prepreg tape is 46-48%.

[0047] Embodiment 2: A method for preparing an improved two-dimensional PET+CFRT prepreg based on a special-shaped PET substrate, characterized in that it comprises the following steps:

[0048] Step SS1: pre-treating the continuous fiber CFRT, including: spraying a pre-treatment liquid on the surface of the continuous fiber CFRT, and subjecting the continuous fiber CFRT to a suffocating treatment at 65-70° C. and 80-85% relative humidity for 12-18 hours;

[0049] Step SS2: impregnation treatment, including: washing and drying the pretreated continuous fiber CFRT, and then, after passing through the guide wire, impregnating it in a PET melt under reduced pressure to obtain a PET+CFRT prepreg; the temperature of the PET melt in step SS2 is 290° C.;

[0050] Step SS3: Prepreg tape preparation, including: using an automatic prepreg slitting machine to slit the PET+CFRT prepreg into prepreg tapes with a standard width of 6.35 mm used by an automatic fiber placement machine;

[0051] Step SS4: The prepreg tape is automatically laid out by an automatic wire laying machine to generate a PET+CFRT preform, the PET+CFRT preform is cut, and the cut PET+CFRT preform is sequentially dried and hot-pressed to be cured, and the upper and lower surfaces of the cured PET+CFRT preform are respectively compounded with a release film and a release paper to obtain a two-dimensional PET+CFRT prepreg cloth.

[0052] The hot pressing treatment for curing in step SS4 includes: curing in an autoclave, with a curing temperature of 185 to 220° C., a curing time of 7 to 9 hours, and a curing pressure of 1.2 to 2.0 MPa.

[0053] In step SS4, the prepreg tape is automatically laid by an automatic wire laying machine to generate a PET+CFRT preform, which specifically includes:

[0054] Step SS41: Select the minimum square size for preparing the two-dimensional PET+CFRT prepreg, and lay the single-sided adhesive polytetrafluoroethylene cloth on the surface of the corresponding square area on the laying platform;

[0055] Step SS42: At the four vertex corners of the square area, the "laying straight track" function of the automatic wire laying machine is used. The automatic wire laying machine lays a prepreg tape in sequence at the layer design angles α, β, γ, and δ respectively. One side of the prepreg tape just presses the vertex, and the other side is located in the square area. The laying positions of α, β, γ, and δ are determined according to their angles. Among them, the upper left vertex corner of the square area lays a prepreg tape with a design angle of 0°, the upper right vertex corner lays a prepreg tape with a design angle of 0° to 90°, the lower left vertex corner lays a prepreg tape with a design angle of 90°, and the lower right vertex corner lays a prepreg tape with a design angle of -90° to 0°;

[0056] Step SS43: the automatic fiber placement machine continues to lay down a prepreg tape in the square area in the order of angles α→β→γ→δ, wherein the center line of the next prepreg tape is spaced apart from the center line of the previous prepreg tape by ai, where ai=6.35n, n is an integer, and i corresponds to α, β, γ, and δ respectively;

[0057] Step SS44: the automatic fiber placement machine places the next prepreg tape in the order of α→β→γ→δ from the center line position of the previous prepreg tape corresponding to the same design angle in the previous round into the working area at a certain distance ai;

[0058] Step SS45: repeat step SS44 until the centerline position of the prepreg tape corresponding to the next interval ai falls outside the square area, skip the design angle, and continue to lay the prepreg tape corresponding to the next design angle until the centerline positions of all prepreg tapes corresponding to the next interval ai fall outside the square area, and stop laying;

[0059] Step SS46: The automatic fiber placement machine places a prepreg tape in the order of α→β→γ→δ from the center line position of the first prepreg tape corresponding to the same design angle into the working area, and places the next prepreg tape only next to the first prepreg tape. The distance between the center lines of the two adjacent prepreg tapes is 6.35 mm, and a new round of fiber placement begins;

[0060] Step SS47: The automatic fiber placement machine places the next prepreg tape at a certain distance ai from the center line position of the previous prepreg tape corresponding to the same design angle in the previous round into the working area in the order of α→β→γ→δ;

[0061] Step SS48: Repeat the steps of SS47 until the centerline position of the prepreg tape corresponding to the next interval ai falls outside the square area, skip the design angle, and continue to lay the prepreg tape corresponding to the next design angle until the centerline positions of all prepreg tapes corresponding to the next interval ai fall outside the square area, completing the laying of this round of prepreg tapes;

[0062] Step SS49: The automatic wire laying machine starts from the first prepreg tape corresponding to the same design angle in the previous round in the laying order of α→β→γ→δ, repeats steps SS46 to SS48, and starts another round of wire laying until the prepreg tapes with the same design angle fill the square area, skips the design angle, and continues the next round of wire laying until all prepreg tapes with the same design angle fill the square area, completes the automatic laying of all prepreg tapes, and obtains an automatic wire laying PET+CFRT preform. The PET+CFRT preform cutting in step SS4 includes: cutting the PET+CFRT preform along the boundary line of the square area, and the upper and lower surfaces of the cut PET+CFRT preform are respectively compounded with release film and release paper to obtain a two-dimensional PET+CFRT prepreg cloth. The PET is polyethylene terephthalate. The moving speed of the continuous fiber CFRT during the impregnation process is 12-20m / min. The pretreatment liquid is prepared from the following components in mass percentage: 5-6% hydrophilic amino silicone oil, 1-3% sodium dodecylbenzene sulfonate, 2-3% sodium chloride and the balance water. The thickness of the prepreg tape is 0.5-0.8mm and the width is 100-800mm. The mass content of continuous fiber CFRT in the prepreg tape is 46-48%.

[0063] Embodiment 3: A method for preparing an improved two-dimensional PET+CFRT prepreg based on a special-shaped PET substrate, characterized in that it comprises the following steps:

[0064] Step SS1: pre-treating the continuous fiber CFRT, including: spraying a pre-treatment liquid on the surface of the continuous fiber CFRT, and subjecting the continuous fiber CFRT to a suffocating treatment at 65-70° C. and 80-85% relative humidity for 12-18 hours;

[0065] Step SS2: impregnation treatment, including: washing and drying the pretreated continuous fiber CFRT, and then impregnating it in a PET melt under reduced pressure after passing through the guide wire to obtain a PET+CFRT prepreg; the temperature of the PET melt in step SS2 is 300° C.;

[0066] Step SS3: Prepreg tape preparation, including: using an automatic prepreg slitting machine to slit the PET+CFRT prepreg into prepreg tapes with a standard width of 6.35 mm used by an automatic fiber placement machine;

[0067] Step SS4: The prepreg tape is automatically laid out by an automatic wire laying machine to generate a PET+CFRT preform, the PET+CFRT preform is cut, and the cut PET+CFRT preform is sequentially dried and hot-pressed to be cured, and the upper and lower surfaces of the cured PET+CFRT preform are respectively compounded with a release film and a release paper to obtain a two-dimensional PET+CFRT prepreg cloth.

[0068] The hot pressing treatment for curing in step SS4 includes: curing in an autoclave, with a curing temperature of 185 to 220° C., a curing time of 7 to 9 hours, and a curing pressure of 1.2 to 2.0 MPa.

[0069] In step SS4, the prepreg tape is automatically laid by an automatic wire laying machine to generate a PET+CFRT preform, which specifically includes:

[0070] Step SS41: Select the minimum square size for preparing the two-dimensional PET+CFRT prepreg, and lay the single-sided adhesive polytetrafluoroethylene cloth on the surface of the corresponding square area on the laying platform;

[0071] Step SS42: At the four vertex corners of the square area, the "laying straight track" function of the automatic wire laying machine is used. The automatic wire laying machine lays a prepreg tape in sequence at the layer design angles α, β, γ, and δ respectively. One side of the prepreg tape just presses the vertex, and the other side is located in the square area. The laying positions of α, β, γ, and δ are determined according to their angles. Among them, the upper left vertex corner of the square area lays a prepreg tape with a design angle of 0°, the upper right vertex corner lays a prepreg tape with a design angle of 0° to 90°, the lower left vertex corner lays a prepreg tape with a design angle of 90°, and the lower right vertex corner lays a prepreg tape with a design angle of -90° to 0°;

[0072] Step SS43: the automatic fiber placement machine continues to lay down a prepreg tape in the square area in the order of angles α→β→γ→δ, wherein the center line of the next prepreg tape is spaced apart from the center line of the previous prepreg tape by ai, where ai=6.35n, n is an integer, and i corresponds to α, β, γ, and δ respectively;

[0073] Step SS44: the automatic fiber placement machine places the next prepreg tape in the order of α→β→γ→δ from the center line position of the previous prepreg tape corresponding to the same design angle in the previous round into the working area at a certain distance ai;

[0074] Step SS45: repeat step SS44 until the centerline position of the prepreg tape corresponding to the next interval ai falls outside the square area, skip the design angle, and continue to lay the prepreg tape corresponding to the next design angle until the centerline positions of all prepreg tapes corresponding to the next interval ai fall outside the square area, and stop laying;

[0075] Step SS46: The automatic fiber placement machine places a prepreg tape in the order of α→β→γ→δ from the center line position of the first prepreg tape corresponding to the same design angle into the working area, and places the next prepreg tape only next to the first prepreg tape. The distance between the center lines of the two adjacent prepreg tapes is 6.35 mm, and a new round of fiber placement begins;

[0076] Step SS47: The automatic fiber placement machine places the next prepreg tape at a certain distance ai from the center line position of the previous prepreg tape corresponding to the same design angle in the previous round into the working area in the order of α→β→γ→δ;

[0077] Step SS48: Repeat the steps of SS47 until the centerline position of the prepreg tape corresponding to the next interval ai falls outside the square area, skip the design angle, and continue to lay the prepreg tape corresponding to the next design angle until the centerline positions of all prepreg tapes corresponding to the next interval ai fall outside the square area, completing the laying of this round of prepreg tapes;

[0078] Step SS49: The automatic wire laying machine starts from the first prepreg tape corresponding to the same design angle in the previous round in the laying order of α→β→γ→δ, repeats steps SS46 to SS48, and starts another round of wire laying until the prepreg tapes with the same design angle fill the square area, skips the design angle, and continues the next round of wire laying until all prepreg tapes with the same design angle fill the square area, completes the automatic laying of all prepreg tapes, and obtains an automatic wire laying PET+CFRT preform. The PET+CFRT preform cutting in step SS4 includes: cutting the PET+CFRT preform along the boundary line of the square area, and the upper and lower surfaces of the cut PET+CFRT preform are respectively compounded with release film and release paper to obtain a two-dimensional PET+CFRT prepreg cloth. The PET is polyethylene terephthalate. The moving speed of the continuous fiber CFRT during the impregnation process is 12-20m / min. The pretreatment liquid is prepared from the following components in mass percentage: 5-6% hydrophilic amino silicone oil, 1-3% sodium dodecylbenzene sulfonate, 2-3% sodium chloride and the balance water. The thickness of the prepreg tape is 0.5-0.8mm and the width is 100-800mm. The mass content of continuous fiber CFRT in the prepreg tape is 46-48%.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing an improved two-dimensional PET+CFRT prepreg based on a special-shaped PET substrate, characterized in that: The steps include: Step SS1: pre-treating the continuous fiber CFRT, including: spraying a pre-treatment liquid on the surface of the continuous fiber CFRT, and subjecting the continuous fiber CFRT to a suffocating treatment at 65-70° C. and 80-85% relative humidity for 12-18 hours; Step SS2: impregnation treatment, including: washing and drying the pretreated continuous fiber CFRT, and then impregnating it in a PET melt under reduced pressure after passing through the guide wire to obtain a PET+CFRT prepreg; Step SS3: Prepreg tape preparation, including: using an automatic prepreg slitting machine to slit the PET+CFRT prepreg into prepreg tapes with a standard width of 6.35 mm used by an automatic fiber placement machine; Step SS4: The prepreg tape is automatically laid out by an automatic wire laying machine to generate a PET+CFRT preform, the PET+CFRT preform is cut, and the cut PET+CFRT preform is sequentially dried and hot-pressed to be cured, and the upper and lower surfaces of the cured PET+CFRT preform are respectively compounded with a release film and a release paper to obtain a two-dimensional PET+CFRT prepreg cloth.

2. The method for preparing an improved two-dimensional PET+CFRT prepreg based on a special-shaped PET substrate according to claim 1, characterized in that: The temperature of the PET melt in step SS2 is 280-300°C.

3. The method for preparing an improved two-dimensional PET+CFRT prepreg based on a special-shaped PET substrate according to claim 1, characterized in that: The hot pressing treatment for curing in step SS4 includes: curing in an autoclave, with a curing temperature of 185 to 220° C., a curing time of 7 to 9 hours, and a curing pressure of 1.2 to 2.0 MPa.

4. The method for preparing an improved PET+CFRT prepreg based on a special-shaped PET substrate according to claim 1, characterized in that: In step SS4, the prepreg tape is automatically laid by an automatic wire laying machine to generate a PET+CFRT preform, which specifically includes: Step SS41: Select the minimum square size for preparing the two-dimensional PET+CFRT prepreg, and lay the single-sided adhesive polytetrafluoroethylene cloth on the surface of the corresponding square area on the laying platform; Step SS42: At the four corners of the square area, the "laying straight track" function of the automatic wire laying machine is used. The automatic wire laying machine lays a prepreg tape in sequence at the layer design angles α, β, γ, and δ respectively. One side of the prepreg tape just presses the corner, and the other side is located in the square area. The laying positions of α, β, γ, and δ are determined according to their angles. Among them, the upper left corner of the square area lays a prepreg tape with a design angle of 0°, the upper right corner lays a prepreg tape with a design angle of 0° to 90°, the lower left corner lays a prepreg tape with a design angle of 90°, and the lower right corner lays a prepreg tape with a design angle of -90° to 0°; Step SS43: the automatic fiber placement machine continues to lay down a prepreg tape in the square area in the order of angles α→β→γ→δ, wherein the center line of the next prepreg tape is spaced apart from the center line of the previous prepreg tape by ai, where ai=6.35n, n is an integer, and i corresponds to α, β, γ, and δ respectively; Step SS44: the automatic fiber placement machine places the next prepreg tape in the order of α→β→γ→δ from the center line position of the previous prepreg tape corresponding to the same design angle in the previous round into the working area at a certain distance ai; Step SS45: repeat step SS44 until the centerline position of the prepreg tape corresponding to the next interval ai falls outside the square area, skip the design angle, and continue to lay the prepreg tape corresponding to the next design angle until the centerline positions of all prepreg tapes corresponding to the next interval ai fall outside the square area, and stop laying; Step SS46: The automatic fiber placement machine places a prepreg tape in the order of α→β→γ→δ from the center line position of the first prepreg tape corresponding to the same design angle into the working area, and places the next prepreg tape only next to the first prepreg tape. The distance between the center lines of the two adjacent prepreg tapes is 6.35 mm, and a new round of fiber placement begins; Step SS47: The automatic fiber placement machine places the next prepreg tape at a certain distance ai from the center line position of the previous prepreg tape corresponding to the same design angle in the previous round into the working area in the order of α→β→γ→δ; Step SS48: Repeat the steps of SS47 until the centerline position of the prepreg tape corresponding to the next interval ai falls outside the square area, skip the design angle, and continue to lay the prepreg tape corresponding to the next design angle until the centerline positions of all prepreg tapes corresponding to the next interval ai fall outside the square area, completing the laying of this round of prepreg tapes; Step SS49: The automatic wire placing machine follows the laying order of α→β→γ→δ, starting from the first prepreg tape corresponding to the same design angle in the previous round, repeats steps SS46 to SS48, and starts another round of wire placing until the prepreg tapes with the same design angle fill the square area, skips the design angle, and continues with the next round of wire placing until all prepreg tapes with the same design angle fill the square area, completing the automatic laying of all prepreg tapes to obtain an automatically placed PET+CFRT preform.

5. The method for preparing an improved two-dimensional PET+CFRT prepreg based on a special-shaped PET substrate according to claim 4, characterized in that: The PET+CFRT preform cutting in step SS4 includes: cutting the PET+CFRT preform along the boundary line of the square area, and compounding the upper and lower surfaces of the cut PET+CFRT preform with release film and release paper respectively to obtain a two-dimensional PET+CFRT prepreg.

6. The method for preparing an improved two-dimensional PET+CFRT prepreg based on a special-shaped PET substrate according to claim 1, characterized in that: The PET is polyethylene terephthalate.

7. The method for preparing an improved two-dimensional PET+CFRT prepreg based on a special-shaped PET substrate according to claim 1, characterized in that: The moving speed of the continuous fiber CFRT during the impregnation process is 12-20 m / min.

8. The method for preparing an improved two-dimensional PET+CFRT prepreg based on a special-shaped PET substrate according to claim 1, characterized in that: The pretreatment liquid is prepared from the following components in percentage by mass: 5-6% of hydrophilic amino silicone oil, 1-3% of sodium dodecylbenzene sulfonate, 2-3% of sodium chloride and the balance of water.

9. The method for preparing an improved two-dimensional PET+CFRT prepreg based on a special-shaped PET substrate according to claim 1, characterized in that: The prepreg tape has a thickness of 0.5-0.8 mm and a width of 100-800 mm.

10. The method for preparing an improved two-dimensional PET+CFRT prepreg based on a special-shaped PET substrate according to claim 1, characterized in that: The mass content of the continuous fiber CFRT in the prepreg tape is 46-48%.