A continuous fiber reinforced PET composite material for automobile wheel cover and preparation method thereof

Abstract

The invention discloses a continuous fiber reinforced PET composite material for automobile wheel covers and a preparation method thereof. The composite material comprises a fiber layer and a functional layer composited with the fiber layer. The raw materials are calculated by weight: the fiber layer comprises 65-70 parts of PET, 25-30 parts of carbon fiber, 20-25 parts of glass fiber, 10-15 parts of viscose fiber and 12-15 parts of SEP; the functional layer comprises 25-30 parts of SEBS resin, 5-8 parts of nanocellulose crystals, 1-1.5 parts of triallyl isocyanurate, 1-2 parts of crosslinking agent, 1-1.5 parts of compatibilizer, 0.5-1.5 parts of flame retardant and 1.5-2 parts of binder; the composite material comprises the steps of preparing the fiber layer, preparing the functional layer and composite treatment. The composite material can enhance the comprehensive performance of PET through the raw material ratio, and can make the matching effect between fibers better through composite treatment, thereby greatly improving the performance of the composite material.

Description

Technical Field

[0001] The invention relates to the technical field of automobile wheel cover materials, and in particular to a continuous fiber reinforced PET composite material for automobile wheel covers and a preparation method thereof. Background Art

[0002] With the continuous development of industrial manufacturing technology and plastic modification technology, replacing steel with plastic has become a trend in the automotive manufacturing, mobile office and home furnishing industries. Many traditional metal parts are gradually replaced by high-performance plastics. Continuous fiber reinforced thermoplastic composites have great market application space in the automotive industry due to their light weight, high stiffness and high toughness.

[0003] Continuous Fibre Reinforced Thermoplastics (CFRTP) refers to a new type of high-strength, high-rigidity, high-toughness composite material that uses continuous fibers as reinforcement materials and thermoplastic resins as the matrix, manufactured through a special process; continuous fibers, as reinforcements for composite materials, determine the main mechanical properties of composite materials in various environments (performance along the fiber direction), and also affect the volume, performance and designability of the material, thus becoming the core of composite material research and development. Continuous fiber reinforced composite materials have been highly valued in the civil aviation field, which has always been demanding quality reduction, due to their advantages such as light weight, high structural strength and relatively mature technology. They are widely used in civil aviation engine cap cones, fan rotor stators and outlet guide vanes and their casings and containment rings, engine nacelles and reverse thrust devices, muffler structures, and high and low pressure turbine blades.

[0004] PET has excellent heat resistance, weather resistance, electrical properties, rigidity and strength. Its reinforcement, flame retardant modification and alloying modification can significantly improve its heat resistance, modulus, toughness, dimensional stability and flame retardancy. It is widely used in the fields of electronics, automobiles and home appliances. Carbon fiber has many excellent properties. Carbon fiber has high axial strength and modulus, low density, high specific performance, no creep, ultra-high temperature resistance in non-oxidizing environment, good fatigue resistance, specific heat and conductivity between non-metal and metal, small thermal expansion coefficient and anisotropy, good corrosion resistance, good X-ray transmittance, good electrical and thermal conductivity, good electromagnetic shielding, etc.

[0005] The film lamination method is to stack fiber reinforcement material layers and thermoplastic material sheets, heat and pressurize them to make the polymer flow between the reinforcement materials, and then solidify. The pressure applied by the film lamination method must be large enough to allow the melt to enter between the fiber layers without flowing between the reinforcement layers. The typical pressure value is less than 2MPa. The powder impregnation process is not limited by the viscosity of the matrix, and high molecular weight polymers can be distributed in the fibers.

[0006] The film lamination method has the disadvantage that the high-viscosity matrix resin is difficult to impregnate into the fiber; the powder impregnation method has the disadvantage that the impregnation can only be completed during the molding process and the powder is easy to be lost; the time, temperature and pressure required for impregnation depend on the size and distribution of the powder particles; resulting in the improvement and enhancement effect on PET not reaching an optimal level. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a continuous fiber reinforced PET composite material for automobile wheel covers and a preparation method thereof.

[0008] The technical solution of the present invention is: a continuous fiber reinforced PET composite material for automobile wheel covers and a preparation method thereof, comprising a fiber layer and a functional layer composited with the fiber layer, wherein the raw materials are calculated by weight:

[0009] The fiber layer includes: 65-70 parts of PET, 25-30 parts of carbon fiber, 20-25 parts of glass fiber, 10-15 parts of viscose fiber, and 12-15 parts of SEP;

[0010] The functional layer comprises: 25-30 parts of SEBS resin, 5-8 parts of nanocellulose crystals, 1-1.5 parts of triallyl isocyanurate, 1-2 parts of a crosslinking agent, 1-1.5 parts of a compatibilizer, 0.5-1.5 parts of a flame retardant, and 1.5-2 parts of a binder.

[0011] Description: Through the ratio of the above ingredients and the composite of the raw materials of the fiber layer and the functional layer, the comprehensive performance of PET can be enhanced, so that the PET material has excellent mechanical properties, good dimensional stability, high heat resistance, good surface gloss and good color stability. Through the setting of the raw materials of the fiber layer, carbon fiber can improve its fatigue resistance, high temperature resistance and corrosion resistance. Glass fiber has the advantages of good modulus performance, strong heat resistance, good corrosion resistance, high mechanical strength and low cost and easy availability, but has the disadvantage of being brittle. Through the composite of carbon fiber and PET, the performance of each other is improved and the overall effect is improved. Viscose fiber can promote melting between the individual components. Through the setting of the functional layer, the elastomer of SEBS can be used to toughen PET and improve the impact strength; and it has a certain anti-slip effect; through the setting of the other additives, the composite material can be made multifunctional. Nanocellulose crystals have the advantages of low density, high strength, biodegradability and renewability, which can improve the tensile strength of PET.

[0012] Furthermore, the PET adopts modified PET polyester after modification treatment, and the modification treatment steps are:

[0013] 1) Take terephthalic acid, ethylene glycol and sodium stearate in a mass ratio of 45-55:20:1-1.5 for later use;

[0014] 2) stirring sodium stearate and one third of the mass of ethylene glycol at a temperature of 85 to 95° C., and then dispersing by ultrasonic oscillation for 25 to 35 minutes to prepare a sodium stearate-ethylene glycol solution; mixing the sodium stearate-ethylene glycol solution, terephthalic acid, and the remaining two thirds of the mass of ethylene glycol, and performing an esterification reaction to obtain an esterified product;

[0015] 3) taking 5-8 wt% of graphene oxide and 2-4 wt% of polyimide accounting for terephthalic acid, ultrasonically dispersing the graphene oxide in deionized water, then adding the polyimide thereto, stirring at 75-80° C. for 2-3 h, filtering, washing and drying the reaction product to obtain a mixture;

[0016] 4) adding the mixture to the esterified product to carry out a pre-polycondensation reaction to obtain a pre-polycondensation product; and then carrying out a polycondensation reaction to obtain the modified PET polyester.

[0017] Description: By modifying PET and using sodium stearate monomer, the intrinsic viscosity and crystallization rate of PET polyester are improved; graphene oxide and polyimide are used to improve the permeability and adhesion of the modified PET material, making PET have good toughness, good plasticity, easy processing and molding, short molding cycle and high impact strength; and the addition of the two can increase the density between molecules and the attraction between molecular chains.

[0018] Furthermore, the temperature of the esterification reaction is 240-245°C, the pressure is 0.28 MPa, and the time is 2-4 hours; the temperature of the pre-polycondensation reaction is 260-265°C, the pressure is 6-10 kPa, and the time is 45-60 minutes; the temperature of the polycondensation reaction is 280°C, the pressure is 0-70 Pa, and the time is 2-3 hours.

[0019] Note: The further limitation of the above reaction parameters is more suitable for the production of modified PET polyester. Exceeding this range may affect the performance of the modified PET polyester obtained and further affect the performance of the composite material.

[0020] Furthermore, the cross-linking agent is chlorinated polyethylene; the compatibilizer is maleic anhydride grafted polyethylene PE-g-MAH; the flame retardant is ammonium polyphosphate; and the binder is a mixture of terephthalic acid metal salt and silane coupling agent in a ratio of 3:1.

[0021] Note: Through further setting of the above additives, each of them can achieve the best functional effect in the production reaction, promoting the compounding of raw materials and the expression of performance.

[0022] Furthermore, the preparation method of the nanocellulose crystals is:

[0023] S1-1, adding cellulose powder to tetrabutyl phosphine hydroxide aqueous solution at a mass ratio of 1:20-25, and mixing them evenly to obtain a mixture; the mass concentration of the tetrabutyl phosphine hydroxide aqueous solution is 35%;

[0024] S1-2, shaking the mixture at 45° C. for 1 h, ultrasonically dispersing for 25 to 35 min, then adding 24 to 50 wt % of methyl cellulose and 0.2 to 1.1 wt % of azodicarbonamide, stirring for 2 to 3 h, and then ultrasonically dispersing for 35 to 45 min to obtain a mixed solution;

[0025] S1-3, using 1 mol / L HCl aqueous solution to adjust the pH value of the mixed solution to 4-5, adding glutaraldehyde accounting for 0.06-1.2 wt % of the weight of the mixed solution, and then subjecting the mixture to centrifugation and drying to obtain nanocellulose crystals.

[0026] Description: Through the setting of the above method, the obtained nanocellulose crystal particle size distribution is uniform and the yield is high; by combining with methyl cellulose and azodicarbonamide, cellulose nanocrystals with better characteristics are obtained, retaining the high crystallinity of the cellulose nanocrystals themselves, excellent strength performance, reducing the cracking, warping and other problems of the composite material; and it has a natural affinity for the composite material, which has the effect of weakening the local stress of the interface; under the action of stress, the cellulose nanocrystal particles will slide along the surface of the filling material, and the broken bonds will be reconnected into new bonds, so that the matrix and the material can still maintain a certain bonding strength, reducing the degree of damage to the composite material.

[0027] Furthermore, the ultrasonic dispersion frequency is 33-40 kHz, the centrifugal parameter is 1000-1500 r / min for 15 min, and the drying parameter is 75-85° C. for 2 h.

[0028] Note: By further setting the above parameters, the dispersion and centrifugal drying effects are better during the preparation and production process, which is more suitable for the preparation of nanocellulose crystals. Exceeding this range may reduce the uniformity and other properties of the product.

[0029] A method for preparing a continuous fiber reinforced PET composite material for an automobile wheel cover comprises the following steps:

[0030] S1. Preparation of fiber layer:

[0031] After mixing PET and SEP according to the weight ratio, they are converted into primary mixed fibers by melt extrusion, and the primary mixed fibers, carbon fibers, glass fibers, and viscose fibers are put into a mixing box for mixing, and then the mixed fibers are put into an opener for opening; after opening, they are sent to a multi-bin mixing machine for mixing, and long mixed fiber bundles are obtained after mixing;

[0032] The long mixed fiber bundle is placed in a roller carding machine for carding and spinning into a long fiber web;

[0033] S2. Preparation of functional layer:

[0034] S2-1. After melt mixing SEBS resin, triallyl isocyanurate, crosslinking agent, flame retardant and compatibilizer according to weight proportion, the short fibers are converted into short fibers by extrusion, and the short fibers are put into an opener for opening; after opening, the short fibers are sent to a multi-bin cotton mixer for mixing, and short fiber bundles are obtained after mixing; the short mixed fiber bundles are sent to an airflow carding machine for carding to form a short fiber web;

[0035] S2-2, take one fifth of the binder and spray it evenly on the short fiber web, take another one fifth of the nanocellulose crystal powder with a particle size of 25-75 nm and spray it evenly on the short fiber web, repeat the spraying alternately until the binder and the nanocellulose crystals are completely used, and then get the functional web layer and dry it for use;

[0036] S3. Composite processing:

[0037] The long fiber web and the functional web layer are sent to the web laying machine for alternate laying in sequence, with the long fiber web located between the functional web layers to form a multi-layer fiber web, which is then sent to the needle punching machine for needle punching treatment. After the needle punching is completed, the multi-layer fiber web is subjected to hot-scalding compounding and cooling treatment at 200-220°C to obtain a continuous fiber reinforced PET composite material.

[0038] Description: Through the setting of the above method, the raw materials can give full play to their respective functional effects and produce better effects on each other; thereby enhancing the various properties of the PET composite material, making it more suitable for the production and use of automobile wheel covers; by preparing the fiber layer as a long fiber layer, PET, SEP, carbon fiber, glass fiber, and viscose fiber can be initially compounded to form a long fiber material that initially improves the performance of PET; through the setting of short fibers in the functional layer, the elastic effect of SEBS resin can be utilized; through the addition of other additives and the spraying of nanocellulose crystal powder and binder, the short fibers can better carry various functional effects; through the setting of the composite treatment, the combination of long and short fibers is made tighter, the coordination effect between them is better, and the performance of the composite material is improved to a great extent.

[0039] Furthermore, the needling process is as follows: at room temperature and an initial ambient humidity of 35-45%, the multilayer fiber web is preheated at a heating rate of 5°C / min using a fiberboard press until the temperature reaches 95-105°C, the ambient humidity is adjusted to 70-75%, the constant temperature is maintained for 10-15 minutes, the temperature is increased to 175-179°C at 8°C / min, and then the needling machine is turned on for processing. After completion, it is cooled to room temperature at a cooling rate of 8°C / min.

[0040] Description: Through the above-mentioned needling process, the composite and bonding effects of the multi-layer fiber web can be better. By adjusting the temperature and humidity and the sequence of needling processes, the structures in the multi-layer fiber web can be slowly combined to improve the composite firmness.

[0041] Furthermore, the thickness of the short fiber web is 0.05 to 0.15 mm, and the thickness of the long fiber web is 0.5 to 0.75 mm; and the needle punching density of the needle punching machine is 16 to 25 needles / cm.

[0042] Description: By setting the single-layer thickness of the long and short fibers, the combination effect between the two is better. By setting the needle punching density, it is more suitable for the processing of multi-layer fiber webs.

[0043] Furthermore, the cooling treatment is: cooling to room temperature by water spray cooling method.

[0044] Note: Cooling by the above method can improve the toughness of the obtained composite material.

[0045] The beneficial effects of the present invention are:

[0046] (1) The present invention can enhance the comprehensive performance of PET by adjusting the ratio of ingredients and compounding the raw materials of the fiber layer and the functional layer, so that the PET material has excellent mechanical properties, good dimensional stability, high heat resistance, good surface gloss and good color stability. By setting the raw materials of the fiber layer, the carbon fiber can improve its fatigue resistance, high temperature resistance and corrosion resistance. The glass fiber has the advantages of good modulus performance, strong heat resistance, good corrosion resistance, high mechanical strength and low cost and easy availability, but has the disadvantage of being brittle. By compounding with carbon fiber and PET, the performance of each other is improved and the overall effect is improved. Viscose fiber can promote melting between the individual components. By setting the functional layer, the elastomer of SEBS can be used to toughen PET and improve the impact strength; and it has a certain anti-slip effect; by setting the other additives, the composite material can be made multifunctional. Nanocellulose crystals have the advantages of low density, high strength, biodegradability and renewability, and can improve the tensile strength of PET.

[0047] (2) The present invention modifies PET and improves the intrinsic viscosity and crystallization rate of PET polyester by using sodium stearate monomer; and improves the permeability and adhesion of the modified PET material by using graphene oxide and polyimide, so that PET has good toughness, good plasticity, easy processing and molding, short molding cycle and high impact strength; and the addition of the two can increase the density between molecules and the attraction between molecular chains.

[0048] (3) The present invention achieves uniform particle size distribution and high yield of nanocellulose crystals obtained by the above-mentioned method. By combining with methyl cellulose and azodicarbonamide, cellulose nanocrystals with better properties are obtained, which retain the high crystallinity of the cellulose nanocrystals themselves, have excellent strength properties, and reduce problems such as cracking and warping of the composite material. Moreover, the cellulose nanocrystals have a natural affinity for the composite material, which reduces the local stress of the interface. Under the action of stress, the cellulose nanocrystal particles will slide along the surface of the filling material, and the broken bonds will be reconnected into new bonds, so that a certain bonding strength can be maintained between the matrix and the material, thereby reducing the degree of damage to the composite material.

[0049] (4) The present invention can make the raw materials fully exert their respective functions and produce better effects on each other through the setting of the preparation method; thereby enhancing the various properties of the PET composite material, making it more suitable for the production and use of automobile wheel covers; by preparing the fiber layer as a long fiber layer, PET, SEP, carbon fiber, glass fiber, and viscose fiber can be initially compounded to form a long fiber material that initially improves the performance of PET; by setting the short fibers in the functional layer, the elastic effect of SEBS resin can be utilized; by adding other additives and spraying nanocellulose crystal powder and binder, the short fibers can better carry various functional effects; by setting the composite treatment, the combination of long and short fibers is made tighter, and the coordination effect between them is better, thereby greatly improving the performance of the composite material. DETAILED DESCRIPTION

[0050] The present invention is further described in detail below in conjunction with specific implementation methods to better reflect the advantages of the present invention.

[0051] Embodiment 1:

[0052] A continuous fiber reinforced PET composite material for automobile wheel covers and a preparation method thereof, comprising a fiber layer and a functional layer composited with the fiber layer, wherein the raw materials are calculated by weight:

[0053] The fiber layer includes: 67 parts of PET, 28 parts of carbon fiber, 23 parts of glass fiber, 12 parts of viscose fiber, and 13 parts of SEP;

[0054] The functional layer comprises: 26 parts of SEBS resin, 7 parts of nanocellulose crystals, 1.3 parts of triallyl isocyanurate, 1.5 parts of a crosslinking agent, 1.2 parts of a compatibilizer, 0.8 parts of a flame retardant, and 1.8 parts of a binder;

[0055] The cross-linking agent is chlorinated polyethylene; the compatibilizer is maleic anhydride grafted polyethylene PE-g-MAH; the flame retardant is ammonium polyphosphate; the binder is a mixture of terephthalic acid metal salt and silane coupling agent in a ratio of 3:1; the nanocellulose crystals are commercially available;

[0056] A method for preparing a continuous fiber reinforced PET composite material for an automobile wheel cover comprises the following steps:

[0057] S1. Preparation of fiber layer:

[0058] After mixing PET and SEP according to the weight ratio, they are converted into primary mixed fibers by melt extrusion, and the primary mixed fibers, carbon fibers, glass fibers, and viscose fibers are put into a cotton mixing box for mixing, and then the mixed fibers are put into an opener for opening; after opening, they are sent to a multi-bin cotton mixing machine for mixing, and long mixed fiber bundles are obtained after mixing; the long mixed fiber bundles are put into a roller carding machine for carding and weaving into a long fiber web;

[0059] S2. Preparation of functional layer:

[0060] S2-1. After melt mixing SEBS resin, triallyl isocyanurate, crosslinking agent, flame retardant and compatibilizer according to weight proportion, the short fibers are converted into short fibers by extrusion, and the short fibers are put into an opener for opening; after opening, the short fibers are sent to a multi-bin cotton mixer for mixing, and short fiber bundles are obtained after mixing; the short mixed fiber bundles are sent to an airflow carding machine for carding to form a short fiber web;

[0061] S2-2, take one fifth of the binder and spray it evenly on the short fiber web, take another one fifth of the nanocellulose crystal powder with a particle size of 25-75nm and spray it evenly on the short fiber web, repeat the spraying alternately until the binder and the nanocellulose crystals are completely used, and then obtain the functional web layer, dry it for use; the thickness of the short fiber web is 0.1mm, and the thickness of the long fiber web is 0.6mm;

[0062] S3. Composite processing:

[0063] The long fiber web and the functional web layer are fed into a web laying machine and laid alternately in sequence, with the long fiber web located between the functional web layers to form a multi-layer fiber web, which is then fed into a needle punching machine for needle punching treatment; the needle punching density of the needle punching machine is 20 needles / cm; after the needle punching, the multi-layer fiber web is subjected to hot blanching and cooling treatment at 215°C to obtain a continuous fiber reinforced PET composite material; the cooling treatment is: using a water spray cooling method for 1m 3 / ㎡·h water density, cool to room temperature.

[0064] Example 2

[0065] The difference between this embodiment and embodiment 1 is that the raw material components are different, and the fiber layer includes: 65 parts of PET, 30 parts of carbon fiber, 20 parts of glass fiber, 10 parts of viscose fiber, and 15 parts of SEP;

[0066] The functional layer comprises: 25 parts of SEBS resin, 8 parts of nanocellulose crystals, 1.5 parts of triallyl isocyanurate, 2 parts of a crosslinking agent, 1.5 parts of a compatibilizer, 0.5 parts of a flame retardant, and 2 parts of a binder.

[0067] Example 3

[0068] The difference between this embodiment and embodiment 1 is that the raw material components are different, and the fiber layer includes: 70 parts of PET, 25 parts of carbon fiber, 25 parts of glass fiber, 15 parts of viscose fiber, and 12 parts of SEP;

[0069] The functional layer comprises: 30 parts of SEBS resin, 5 parts of nanocellulose crystals, 1 part of triallyl isocyanurate, 1 part of cross-linking agent, 1 part of compatibilizer, 1.5 parts of flame retardant and 1.5 parts of binder.

[0070] Example 4

[0071] The present embodiment is different from the embodiment 1 in that the hot-stamping and laminating are performed at 200° C.; the needling density of the needling machine is 16 needles / cm; the thickness of the short fiber web is 0.05 mm; and the thickness of the long fiber web is 0.75 mm.

[0072] Example 5

[0073] The present embodiment is different from the embodiment 1 in that the hot-stamping and laminating are carried out at 220° C.; the needling density of the needling machine is 25 needles / cm; the thickness of the short fiber web is 0.15 mm; and the thickness of the long fiber web is 0.5 mm.

[0074] Example 6

[0075] The difference between this embodiment and embodiment 1 is that the PET is modified PET polyester after modification, and the modification process is as follows:

[0076] 1) Take terephthalic acid, ethylene glycol and sodium stearate in a mass ratio of 50:20:1.2 for later use;

[0077] 2) stirring sodium stearate and one third of the mass of ethylene glycol at a temperature of 90° C., and then dispersing by ultrasonic oscillation for 30 minutes to prepare a sodium stearate-ethylene glycol solution; mixing the sodium stearate-ethylene glycol solution, terephthalic acid, and the remaining two thirds of the mass of ethylene glycol, and performing an esterification reaction to obtain an esterified product;

[0078] 3) taking 6 wt % of graphene oxide and 3 wt % of polyimide in terephthalic acid, ultrasonically dispersing the graphene oxide in deionized water, then adding polyimide thereto, stirring at 77° C. for 2.5 h, filtering, washing and drying the reaction product to obtain a mixture;

[0079] 4) adding the mixture to the esterified product to carry out a pre-polycondensation reaction to obtain a pre-polycondensation product; and then carrying out a polycondensation reaction to obtain the modified PET polyester.

[0080] The temperature of the esterification reaction is 242°C, the pressure is 0.28MPa, and the time is 3h; the temperature of the pre-polycondensation reaction is 263°C, the pressure is 8kPa, and the time is 50min; the temperature of the polycondensation reaction is 280°C, the pressure is 55Pa, and the time is 2.5h.

[0081] Example 7

[0082] The difference between this embodiment and embodiment 6 is that the modified raw material components are different. Step 1) terephthalic acid, ethylene glycol, and sodium stearate are taken in a mass ratio of 55:20:1 for standby use; Step 2) 5wt% of graphene oxide and 4wt% of polyimide are taken in terephthalic acid.

[0083] Example 8

[0084] The difference between this embodiment and embodiment 6 is that the modified raw material components are different. Step 1) terephthalic acid, ethylene glycol, and sodium stearate are taken in a mass ratio of 45:20:1.5 for standby use; Step 2) 8wt% of graphene oxide and 2wt% of polyimide are taken in terephthalic acid.

[0085] Example 9

[0086] The difference between this embodiment and embodiment 6 is that the temperature condition parameters are different. In step 2), the sodium stearate-ethylene glycol solution is prepared by ultrasonication at a temperature of 95°C for 35 minutes; in step 3), the mixture is stirred at 80°C for 2 hours; the esterification reaction temperature is 240°C, the pressure is 0.28MPa, and the time is 4 hours; the temperature of the pre-polycondensation reaction is 265°C, the pressure is 10kPa, and the time is 60 minutes; the temperature of the polycondensation reaction is 280°C, the pressure is 70Pa, and the time is 3 hours.

[0087] Example 10

[0088] The difference between this embodiment and embodiment 6 is that the temperature condition parameters are different. In step 2), the sodium stearate-ethylene glycol solution is prepared by ultrasonication at a temperature of 85°C for 25 minutes; in step 3), the solution is stirred at 75°C for 3 hours; the esterification reaction temperature is 245°C, the pressure is 0.28MPa, and the time is 2 hours; the temperature of the pre-polycondensation reaction is 260°C, the pressure is 6kPa, and the time is 45 minutes; the temperature of the polycondensation reaction is 280°C, the pressure is 0Pa, and the time is 2 hours.

[0089] Embodiment 11

[0090] The difference between this embodiment and embodiment 6 is that the preparation method of the nanocellulose crystals is:

[0091] S1-1, adding cellulose powder to tetrabutyl phosphine hydroxide aqueous solution at a mass ratio of 1:23 and mixing evenly to obtain a mixture; the mass concentration of the tetrabutyl phosphine hydroxide aqueous solution is 35%;

[0092] S1-2, the mixture was shaken at 45° C. for 1 h, ultrasonically dispersed for 30 min, and then 30 wt % of methyl cellulose and 0.6 wt % of azodicarbonamide were added, stirred for 2.5 h, and then ultrasonically dispersed for 40 min to obtain a mixed solution;

[0093] S1-3, using 1 mol / L HCl aqueous solution to adjust the pH value of the mixed solution to 4.5, adding 0.8 wt % of glutaraldehyde to the mixed solution, and then subjecting the mixed solution to centrifugation and drying to obtain nanocellulose crystals.

[0094] The ultrasonic dispersion frequency is 37 kHz, the centrifugal parameter is 1300 r / min for 15 min, and the drying treatment parameter is drying at 80° C. for 2 h.

[0095] Example 12

[0096] The difference between this embodiment and embodiment 11 is that the raw material components of the nanocellulose crystals are different. S1-1, cellulose powder is added to tetrabutylphosphine hydroxide aqueous solution in a ratio of 1:20 and mixed evenly to obtain a mixture; S1-2, 50wt% of methyl cellulose and 0.2wt% of azodicarbonamide are added to the cellulose powder; S1-3, the pH value of the mixed solution is adjusted to 5 using 1mol / L HCl aqueous solution, and 0.06wt% of glutaraldehyde is added to the mixed solution.

[0097] Embodiment 13

[0098] The difference between this embodiment and embodiment 11 is that the raw material components of the nanocellulose crystals are different. S1-1, cellulose powder is added to tetrabutylphosphine hydroxide aqueous solution in a ratio of 1:25 and mixed evenly to obtain a mixture; S1-2, methyl cellulose accounting for 24wt% of the cellulose powder and 1.1wt% of azodicarbonamide are added; S1-3, the pH value of the mixed solution is adjusted to 4 using 1mol / L HCl aqueous solution, and glutaraldehyde accounting for 1.2wt% of the mixed solution is added.

[0099] Embodiment 14

[0100] The difference between this embodiment and embodiment 11 is that the condition parameters are different. S1-2, the mixture is oscillated at 45°C for 1 hour, ultrasonically dispersed for 35 minutes, then stirred for 2 hours, and ultrasonically dispersed for 35 minutes to obtain a mixed solution; the ultrasonic dispersion frequency is 40kHz, the centrifugal parameter is 1000r / min for 15 minutes, and the drying treatment parameter is dried at 85°C for 2 hours.

[0101] Embodiment 15

[0102] The difference between this embodiment and embodiment 11 is that the condition parameters are different. S1-2, the mixture is oscillated at 45°C for 1 hour, ultrasonically dispersed for 25 minutes, then stirred for 3 hours, and then ultrasonically dispersed for 45 minutes to obtain a mixed solution; the ultrasonic dispersion frequency is 33kHz, the centrifugal parameter is 1500r / min for 15 minutes, and the drying treatment parameter is dried at 75°C for 2 hours.

[0103] Example 16

[0104] The difference between this embodiment and embodiment 11 is that the needling process is as follows: at room temperature and an initial ambient humidity of 35-45%, the multilayer fiber web is preheated at a heating rate of 5°C / min using a fiberboard press until the temperature reaches 100°C, the ambient humidity is adjusted to 73%, the constant temperature is maintained for 13 minutes, the temperature is increased to 177°C at 8°C / min, and then the needling machine is turned on for processing. After completion, it is cooled to room temperature at a cooling rate of 8°C / min.

[0105] Embodiment 17

[0106] The difference between this embodiment and embodiment 16 is that the humidity parameters are different, the initial ambient humidity is 35%, and the ambient humidity is adjusted to 70%.

[0107] Embodiment 18

[0108] The difference between this embodiment and embodiment 16 is that the humidity parameters are different, the initial ambient humidity is 45%, and the ambient humidity is adjusted to 75%.

[0109] Embodiment 19

[0110] The difference between this embodiment and embodiment 16 is that the temperature parameters are different. After the temperature is raised to 95°C, the ambient humidity is adjusted, the temperature is kept constant for 15 minutes, and then the temperature is raised to 179°C.

[0111] Embodiment 20

[0112] The difference between this embodiment and embodiment 16 is that the temperature parameters are different. After the temperature is raised to 105°C, the ambient humidity is adjusted, the temperature is kept constant for 10 minutes, and then the temperature is raised to 175°C.

[0113] Experimental example

[0114] 1. The continuous fiber reinforced PET composite materials obtained in Examples 1 to 3 and Example 18 were tested for tensile strength, flexural impact strength and ozone aging (the rate of change of flexural impact strength after 100 hours at 38°C); the test results are as follows:

[0115] 1. Explore the effects of different raw material components and different treatments on the performance of continuous fiber reinforced PET composites;

[0116] Examples 1 to 6, Example 11, and Example 16 were compared, as shown in Table 1;

[0117] Table 1 Experimental results of continuous fiber reinforced PET composites performance under different raw material components

[0118]

[0119] It can be seen from Table 1 that the various properties of Example 16 are better. By comparing Example 1, Example 2 and Example 3, it can be found that the component ratio in Example 1 is the best. By comparing Example 1 with Example 6, it can be seen that after the modified PET polyester of Example 6, the various properties of the continuous fiber reinforced PET composite material are better, and the tensile strength is significantly improved; by comparing Example 6 with Example 11, it can be seen that the nanocellulose crystals of Example 11 have better properties for the continuous fiber reinforced PET composite material. By comparing Example 11 with Example 16, it can be seen that the needle punching treatment of Example 16 can further improve the performance of the continuous fiber reinforced PET composite material.

[0120] 2. Explore the effects of different modified treatment components and condition parameters on the performance of continuous fiber reinforced PET composites;

[0121] Examples 6 to 10 were compared, as shown in Table 2;

[0122] Table 2 Experimental results of continuous fiber reinforced PET composites performance under different modified components and conditions

[0123]

[0124] As can be seen from Table 2, by comparing Example 6, Example 7 and Example 8, it can be found that the modified raw material components of Example 6 are more preferred, and by comparing Example 6, Example 9 and Example 10, comprehensively speaking, the temperature adjustment parameters of Example 6 are more preferred.

[0125] 3. To explore the effects of different processing parameters during the preparation of nanocellulose crystals on the performance of continuous fiber reinforced PET composites;

[0126] Examples 11 to 15 were compared, as shown in Table 3;

[0127] Table 3 Test results of continuous fiber reinforced PET composites obtained by different processing parameters during the preparation of nanocellulose crystals

[0128]

[0129]

[0130] As can be seen from Table 3, by comparing Example 11, Example 12 and Example 13, it can be found that the nanocellulose crystal raw material components of Example 11 are not preferred, and by comparing Example 11, Example 14 and Example 15, it can be found that the condition parameters of Example 11 are preferred.

[0131] 4. Explore the effect of needle punching on the performance of continuous fiber reinforced PET composites;

[0132] Comparative Example 1: The difference from Example 16 is that the initial environmental humidity is 40% and remains unchanged, and the temperature is preheated at a rate of 5°C / min from room temperature until it reaches 100°C, and then the temperature is kept constant for 13 minutes, and then the temperature is increased to 177°C at a rate of 8°C / min, and then the needle loom is turned on for processing;

[0133] Comparative Example 2: The difference between the two is that the temperature is preheated at a rate of 5°C / min from room temperature, the temperature is kept constant for 13 minutes, the temperature is raised to 177°C, and then the needle loom is turned on for processing;

[0134] Examples 16 to 20 were compared, as shown in Table 4;

[0135] Table 4 Effect of needle punching on the performance of continuous fiber reinforced PET composites

[0136]

[0137]

[0138] As can be seen from Table 4, by comparing Example 16, Example 17 and Example 18, it can be concluded that the continuous fiber reinforced PET composite material obtained by processing the humidity using Example 16 has better performance. By comparing Example 16, Example 19 and Example 20, it can be concluded that the temperature parameters set in Example 16 are better on the whole. By comparing Example 16, Comparative Example 1 and Comparative Example 2, it can be concluded that the processing method of Example 16 is more preferred on the whole.

Claims

1. A continuous fiber reinforced PET composite material for automobile wheel covers, characterized in that: Including the fiber layer and the functional layer composited with the fiber layer, the raw materials are calculated by mass: The fiber layer includes: 65-70 parts of PET, 25-30 parts of carbon fiber, 20-25 parts of glass fiber, 10-15 parts of viscose fiber, and 12-15 parts of SEP; The functional layer comprises: 25-30 parts of SEBS resin, 5-8 parts of nanocellulose crystals, 1-1.5 parts of triallyl isocyanurate, 1-2 parts of a crosslinking agent, 1-1.5 parts of a compatibilizer, 0.5-1.5 parts of a flame retardant, and 1.5-2 parts of a binder; The PET adopts modified PET polyester after modification treatment, and the modification treatment steps are: 1) Take terephthalic acid, ethylene glycol and sodium stearate in a mass ratio of 45-55:20:1-1.5 for later use; 2) At a temperature of 85-95°C, sodium stearate is stirred with one-third of ethylene glycol, and then dispersed by ultrasonic oscillation for 25-35 minutes to prepare a sodium stearate-ethylene glycol solution; the sodium stearate-ethylene glycol solution, terephthalic acid and the remaining two-thirds of ethylene glycol are mixed to carry out an esterification reaction to obtain an esterified product; 3) Taking 5-8 wt% of graphene oxide and 2-4 wt% of polyimide in terephthalic acid, ultrasonically dispersing the graphene oxide in deionized water, then adding polyimide thereto, stirring at 75-80° C. for 2-3 h, filtering, washing, and drying the reaction product to obtain a mixture; 4) adding the mixture to the esterified product to carry out a pre-polycondensation reaction to obtain a pre-polycondensation product; and then carrying out a polycondensation reaction to obtain the modified PET polyester.

2. The continuous fiber reinforced PET composite material for automobile wheel covers according to claim 1, characterized in that: The temperature of the esterification reaction is 240-245°C, the pressure is 0.28 MPa, and the time is 2-4 hours; the temperature of the pre-polycondensation reaction is 260-265°C, the pressure is 6-10 kPa, and the time is 45-60 minutes; the temperature of the polycondensation reaction is 280°C, the pressure is 0-70 Pa, and the time is 2-3 hours.

3. The continuous fiber reinforced PET composite material for automobile wheel covers according to claim 2, characterized in that: The cross-linking agent is chlorinated polyethylene; the compatibilizer is maleic anhydride grafted polyethylene PE-g-MAH; the flame retardant is ammonium polyphosphate; and the binder is a mixture of terephthalic acid metal salt and silane coupling agent in a ratio of 3:

1.

4. The continuous fiber reinforced PET composite material for automobile wheel covers according to claim 1, characterized in that: The preparation method of the nanocellulose crystals is: S1-1, adding cellulose powder to tetrabutyl phosphine hydroxide aqueous solution at a mass ratio of 1:20-25, and mixing evenly to obtain a mixture; the mass concentration of the tetrabutyl phosphine hydroxide aqueous solution is 35%; S1-2, shaking the mixture at 45° C. for 1 h, ultrasonically dispersing for 25 to 35 min, then adding 24 to 50 wt % of methyl cellulose and 0.2 to 1.1 wt % of azodicarbonamide, stirring for 2 to 3 h, and then ultrasonically dispersing for 35 to 45 min to obtain a mixed solution; S1-3, using 1 mol / L HCl aqueous solution to adjust the pH value of the mixed solution to 4-5, adding glutaraldehyde accounting for 0.06-1.2 wt % of the weight of the mixed solution, and then subjecting the mixture to centrifugation and drying to obtain nanocellulose crystals.

5. The continuous fiber reinforced PET composite material for automobile wheel covers according to claim 4, characterized in that: The ultrasonic dispersion frequency is 33-40 kHz, the centrifugal parameter is 1000-1500 r / min for 15 min, and the drying parameter is 75-85° C. for 2 h.

6. The method for preparing a continuous fiber reinforced PET composite material for automobile wheel covers according to claim 1, characterized in that: The following steps are involved: S1. Preparation of fiber layer: After mixing PET and SEP according to the weight ratio, they are converted into primary mixed fibers by melt extrusion, and the primary mixed fibers, carbon fibers, glass fibers, and viscose fibers are put into a cotton mixing box for mixing, and then the mixed fibers are put into an opener for opening; after opening, they are sent to a multi-bin cotton mixing machine for mixing, and long mixed fiber bundles are obtained after mixing; the long mixed fiber bundles are put into a roller carding machine for carding and weaving into a long fiber web; S2. Preparation of functional layer: S2-1. After melt mixing SEBS resin, triallyl isocyanurate, crosslinking agent, flame retardant and compatibilizer according to weight proportion, the short fibers are converted into short fibers by extrusion, and the short fibers are put into an opener for opening; after opening, the short fibers are sent to a multi-bin cotton mixer for mixing, and short fiber bundles are obtained after mixing; the short mixed fiber bundles are sent to an airflow carding machine for carding to form a short fiber web; S2-2, take one fifth of the binder and spray it evenly on the short fiber web, take another one fifth of the nanocellulose crystal powder with a particle size of 25-75 nm and spray it evenly on the short fiber web, repeat the spraying alternately until the binder and the nanocellulose crystals are completely used, then obtain the functional web layer, dry it for later use; S3. Composite processing: The long fiber web and the functional web layer are sent to the web laying machine for alternate laying in sequence, with the long fiber web located between the functional web layers to form a multi-layer fiber web, which is then sent to the needle punching machine for needle punching treatment. After the needle punching, the multi-layer fiber web is subjected to hot-stamping compounding and cooling treatment at 200-220°C to obtain a continuous fiber reinforced PET composite material.

7. The method for preparing a continuous fiber reinforced PET composite material for automobile wheel covers according to claim 6, characterized in that: The needling process is as follows: at room temperature and an initial ambient humidity of 35-45%, the multilayer fiber web is preheated at a heating rate of 5°C / min using a fiberboard press until the temperature reaches 95-105°C, the ambient humidity is adjusted to 70-75%, the temperature is kept constant for 10-15 minutes, the temperature is raised to 175-179°C at 8°C / min, and then the needling machine is turned on for processing. After completion, it is cooled to room temperature at a cooling rate of 8°C / min.

8. The method for preparing a continuous fiber reinforced PET composite material for automobile wheel covers according to claim 6, characterized in that: The thickness of the short fiber web is 0.05-0.15 mm, and the thickness of the long fiber web is 0.5-0.75 mm; the needle punching density of the needle punching machine is 16-25 needles / cm.

9. The method for preparing a continuous fiber reinforced PET composite material for automobile wheel covers according to claim 6, characterized in that: The cooling treatment is: cooling to room temperature by water spray cooling method.

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