CN-121989471-A - Preparation method, product and application of continuous fiber reinforced thermoplastic composite material

Abstract

The invention discloses a preparation method, a product and an application of a continuous fiber reinforced thermoplastic composite material, and relates to the technical field of battery protection of electronic products, wherein the preparation method comprises the steps of at least one continuous fiber fabric layer and at least 2 thermoplastic resin layers, and the thermoplastic resin layers are arranged as the outermost layers on two sides of the composite material; the puncture resistance of the composite material and the total weight related coefficient alpha of the fibers contained in the composite board per unit area meet the requirement that the thickness of the composite material is less than or equal to 0.4mm, wherein the total weight related coefficient alpha of the fibers contained in the composite board per unit area is 0.175N/(g/m 2 ）~0.425N/（g/m 2 ). Through selection and matching of thermoplastic resin and fiber fabrics, and simple and efficient production process, ultra-thin high puncture resistance of a mobile phone rear cover product is achieved, maximization of the size of a mobile phone battery is met, and accordingly cruising ability of the mobile phone is improved.

Inventors

• DIAO RUIMIN
• HUA GUOFEI
• WANG LIN
• ZHANG LI
• ZOU WEILIANG

Assignees

• 四川龙华光电薄膜股份有限公司

Dates

Publication Date

20260508

Application Date

20260303

Claims (16)

1. 1. A method for preparing a continuous fiber reinforced thermoplastic composite material, which is characterized by comprising the following steps: S1, static electricity removal, namely respectively carrying out static electricity removal on a continuous fiber fabric and a thermoplastic resin film; s2, preheating, namely alternately laminating and placing the continuous fiber fabric and the thermoplastic resin film in sequence after static elimination, wherein the number of the continuous fiber fabric is not less than 1, the number of the thermoplastic resin film is not less than 2, the thermoplastic resin layers are the outermost layers on two sides of the composite material, and preheating the continuous fiber fabric and the thermoplastic resin film; S3, prepressing, namely prepressing the laminated continuous fiber fabric and the thermoplastic resin film after preheating so as to remove interlayer air and form a preform; S4, impregnating and compounding, namely heating the preformed blank to ensure that the thermoplastic resin is always kept in a molten state and impregnated with the continuous fiber fabric, simultaneously applying pressure to ensure that the resin and the fiber are fully impregnated, and controlling the thickness of the composite board to be less than or equal to 0.4mm; S5, cooling and shaping, namely cooling the material while applying pressure after pressure maintaining, and obtaining the composite material after cooling; S6, multi-stage gradient annealing, namely cooling and shaping in the step S5, and performing multi-stage gradient annealing treatment on the composite material, wherein the multi-stage gradient annealing treatment comprises the following steps of: s61, heating the composite material obtained in the step S5 to a temperature within a range of T f +10℃~T f +40 ℃, and keeping the temperature for 0.5-2 hours at a fixed thickness; S62, after the heat preservation in the step S61 is finished, the temperature is reduced to be within the range of T f -40℃~T f -10 ℃ and is preserved for 0.5-2 h; S63, after the heat preservation in the step S62 is finished, slowly cooling the composite material to a temperature which is 30-50 ℃ lower than the heat preservation temperature of the step S62 at a cooling rate which is less than or equal to 5 ℃ per minute, and naturally cooling to room temperature to finally obtain the continuous fiber reinforced thermoplastic composite material; wherein T f is the melt flow temperature of the thermoplastic resin; The puncture resistance of the composite material meets the requirement of 0.175N/(g/m 2 ）~0.425N/（g/m 2 ) of the total weight related coefficient alpha of the fibers contained in the composite board per unit area.
2. 2. The method for producing a continuous fiber-reinforced thermoplastic composite material according to claim 1, wherein the sum of the average thicknesses of the thermoplastic resin layers of the outermost layers on both sides of the composite material is 40% -100% of the average thickness of all the thermoplastic resin layers.
3. 3. The method of producing a continuous fiber-reinforced thermoplastic composite material according to claim 1, wherein the outermost layers on both sides of the composite material are thermoplastic resin layers having an average thickness of not less than 20. Mu.m.
4. 4. The method of claim 1, wherein the continuous fiber fabric layer is a woven glass fiber layer.
5. 5. The method of claim 4, wherein the continuous fiber fabric layer is an E-type alkali-free glass fiber plain weave and/or twill weave.
6. 6. The method for producing a continuous fiber-reinforced thermoplastic composite material according to claim 4, wherein the glass fiber content in the composite material is 40wt% to 65wt%.
7. 7. The method of producing a continuous fiber-reinforced thermoplastic composite material according to claim 1, wherein the porosity of the composite material is 5% or less.
8. 8. The method of producing a continuous fiber-reinforced thermoplastic composite material according to claim 1, wherein the thermoplastic resin is one or more of a polyacrylic resin, a polyamide resin, a polycarbonate resin, a polyester resin and a polyphenylene sulfide resin.
9. 9. The method of producing a continuous fiber-reinforced thermoplastic composite material according to claim 8, wherein the thermoplastic resin is a polycarbonate resin and/or a polyacrylic resin.
10. 10. The method of producing a continuous fiber-reinforced thermoplastic composite material according to claim 1, wherein the preheating temperature in step S2 is 0℃to 50℃lower than the melt flow temperature of the thermoplastic resin.
11. 11. The method for preparing a continuous fiber reinforced thermoplastic composite material according to claim 1, wherein the pre-pressing pressure in the step S3 is 0.05-0.5 MPa.
12. 12. The method of producing a continuous fiber-reinforced thermoplastic composite material according to claim 1, wherein in the step S4, the heating temperature is 10℃to 80℃higher than the resin melt flow temperature.
13. 13. The method of producing a continuous fiber-reinforced thermoplastic composite material according to claim 1, wherein in the step S5, the cooling temperature is 0℃to 60℃lower than the melt flow temperature of the resin.
14. 14. The method for preparing a continuous fiber reinforced thermoplastic composite material according to claim 1, wherein the pressure applied in the step S4 and the step S5 is 0.1MPa to 5MPa.
15. 15. A high puncture resistant continuous fiber reinforced thermoplastic composite prepared according to the method of any one of claims 1-14.
16. 16. Use of a high puncture resistant continuous fiber reinforced thermoplastic composite material prepared according to the method of any one of claims 1-14 in a rear cover of a mobile phone.

Description

Preparation method, product and application of continuous fiber reinforced thermoplastic composite material Technical Field The invention relates to the technical field of battery protection of electronic products, in particular to a preparation method, a product and application of a high puncture resistance continuous fiber reinforced thermoplastic composite material. Background With the advent of the 5G age, new materials are increasingly required by electronic products, and the requirements are also more and more stringent. Among these demands, the light and thin material and the high penetration of signals are important. Based on these two requirements, considering that metallic materials have a shielding effect on 5G signals, related components of 5G electronic products tend to employ non-metallic materials such as glass, ceramic, plastic, thermosetting glass fiber board, and the like. Meanwhile, the requirements of consumers on the cruising of the electronic products are higher and higher, and currently, when the energy density of the battery is increased to reach the bottleneck, the cruising capacity of the electronic products is directly determined by the size of the battery. Therefore, the ultra-thin housing of the electronic product is a challenge to be solved. The glass material has the advantages of small shielding to wireless signals, high rigidity and the like. However, the glass has poor ductility and is extremely fragile, and it is difficult to achieve ultra-thin glass. In the process of attempting ultra-thinning, the yield is greatly reduced, and the cost is greatly improved. The ceramic material is generally formed by sintering metal oxides or borides such as alumina or zirconia, and has the advantages of metallic luster, good heat conduction, high hardness and good surface luster. However, it is difficult to achieve ultra-thin glass materials. Moreover, the ceramic sintering requires a high-temperature process above 1000 ℃ and a later complex processing process caused by high hardness and low toughness, so that the ceramic backboard has low yield, low productivity and extremely high cost and is only applied to a small number of high-end models. The plastic material has the advantages of high strength, impact resistance, wide use temperature range, free dyeing, self-coloring, convenient processing and the like, has the most wide application range, and is easy to realize ultrathin processing. However, the plastic material has a low modulus, so that once the plastic material is thin, the overall rigidity is reduced, the texture is poor, and the battery cannot be effectively protected. At present, the thickness of the mobile phone back shell of the PC/PMMA plastic composite board is 0.5mm to the limit. The thermosetting glass fiber board has high rigidity and high strength, and is also applied to certain fields, the thickness of the main stream is 0.4mm, and compared with the thickness of a pure plastic material, the thermosetting glass fiber board is thinned. However, since the matrix resin of the material is a thermosetting plastic, the toughness is low, the puncture resistance is poor, and the thickness cannot be further reduced. Although the addition of high-performance fiber or thermoplastic resin filler can improve the partial toughness, the cost of raw materials is increased and the processing technique becomes complicated, and thus the method cannot be widely applied. In addition, the production and processing process of the thermosetting glass fiber plates has large environmental pollution, and the later products cannot be recycled and reused, which is contrary to the low-carbon and environment-friendly concept of China. Therefore, an ultrathin, high puncture resistant, simple processing technology and recyclable electronic product shell material is needed to be designed for the problems. The invention patent with the publication number of CN103660308B relates to a continuous fiber fabric reinforced thermoplastic resin composite material and a manufacturing method thereof, wherein the composite material is obtained by cooling and molding continuous fibers after the continuous fibers are melt-impregnated with thermoplastic resin, and has the thickness of 0.20mm0.35Mm, wherein the content of the continuous fiber reinforced fabric is 40wt%And (3) uniformly spreading the continuous fiber fabric, regulating the tension, eliminating static electricity, then entering the thermoplastic resin for melt impregnation, and finally cooling in a cooling unit and winding and forming to obtain the continuous fiber fabric reinforced thermoplastic resin composite material. The composite material mentioned in the patent is prepared by directly cooling after resin melting and dipping and then winding, and in the preparation process, the interface between the obtained composite material resin and the fiber is weak and defects can not be repaired because of too fast cooling and lack of an annealing process