Alumina fiber reinforced cell phone case and process for making the same

Abstract

The application relates to the technical field of mobile phone shells, in particular to an alumina fiber reinforced mobile phone shell and a preparation process thereof. Vinyltriethoxysilane and ethylenediamine are used as raw materials to synthesize a silicon-containing addition product with a terminal secondary amine group, then the silicon-containing addition product is reacted with isophorone diisocyanate to synthesize a diisocyanate oligomer with a side chain containing silicon; the diisocyanate oligomer with the side chain containing silicon is mixed with isophorone diisocyanate and is reacted with polytetrahydrofuran ether glycol 2000 to obtain a silicon-containing polyurethane prepolymer; silica particles are coated on the surface of graphene oxide through a sol-gel method, then the silica particles are modified by using KH550 to obtain an aminated graphene-silica composite filler; the silicon-containing polyurethane prepolymer, epoxy resin, aminated graphene-silica composite filler, curing agent dicyandiamide and accelerator PN-23 are compounded and then coated on the surface of an alumina fiber cloth, and the mobile phone shell is obtained through solidification, lamination, hot pressing and paint spraying.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of mobile phone shells, in particular to an alumina fiber reinforced mobile phone shell and a preparation process thereof. BACKGROUND

[0002] With the continuous progress of communication technology, the smart phone, as the most commonly used communication electronic equipment of contemporary people, integrates life, work, communication and entertainment, brings convenience to people, and has become an indispensable tool in daily life. Its importance is self-evident. The existing mobile phone shells on the market have low impact resistance due to the addition of a large amount of inorganic fillers, are not resistant to falling and are not waterproof, so it is necessary to develop a mobile phone shell with waterproof and drop resistance. SUMMARY

[0003] The application aims to provide an alumina fiber reinforced mobile phone shell and a preparation process thereof to solve the problems in the background art.

[0004] In order to solve the above technical problems, the application provides the following technical scheme: an alumina fiber reinforced mobile phone shell and a preparation process thereof, comprising the following steps:

[0005] Step 1:

[0006] S1: under ice bath conditions, vinyltriethoxysilane is added dropwise into ethylenediamine, and after the addition of the vinyltriethoxysilane is completed, the temperature is controlled to be 25-35 DEG C and reacted for 2-3 hours; under the nitrogen environment, isophorone diisocyanate is added, dibutyltin dilaurate is used as a catalyst, the temperature is raised to 60-70 DEG C, and reacted for 1-2 hours to obtain a silicon-containing diisocyanate oligomer;

[0007] S2: the silicon-containing diisocyanate oligomer and isophorone diisocyanate are mixed in a weight ratio of 1: (1-2) to obtain an isocyanate mixture;

[0008] S3: the isocyanate mixture and polytetrahydrofuran ether glycol 2000 are vacuum dehydrated at 110-120 DEG C for 2-4 hours, under the nitrogen environment, the isocyanate mixture is added into the polytetrahydrofuran ether glycol 2000, dibutyltin dilaurate is used as a catalyst, the temperature is raised to 85-90 DEG C, and reacted for 3-4 hours to obtain a silicon-containing polyurethane prepolymer;

[0009] Step 2:

[0010] Take 0.25-0.3 parts of graphene oxide by weight, add anhydrous ethanol, ultrasonic dispersion for 30 min; adjust pH to 8-10 with potassium hydroxide ethanol solution; heat reflux at 80-90℃ under oil bath for 8-10h, then adjust pH to 7 with hydrochloric acid, filter, wash with water, dry, disperse in ethanol water solution for 30-60min, then add 15-20 parts of ammonia water, stir for 10-15min, add 2-2.5 parts of tetraethyl orthosilicate, control the adding time for 15-20min, stir for 15-18h; after the reaction, add 0.03-0.05 parts of KH550, continue to stir for 6-8h, filter, wash with water, dry to obtain amino-functionalized graphene-silica composite filler;

[0011] Step 3:

[0012] Mix epoxy resin E-44, diluent isobornyl acrylate, silicon-containing polyurethane prepolymer, amino-functionalized graphene-silica composite filler, curing agent dicyandiamide, accelerator PN-23 to obtain mixed resin material; take vacuum-dried alumina fiber cloth, coat the mixed resin material on both sides of the surface, heat and cure to obtain a semi-cured sheet; stack several semi-cured sheets, hot-press to obtain a mobile phone shell substrate; spray paint on one side of the surface of the mobile phone shell substrate and cure to obtain a mobile phone shell.

[0013] Further, in S1, the molar ratio of ethylenediamine, vinyltriethoxysilane and isophorone diisocyanate is 1:2:(1.5-1.8).

[0014] Further, in S2, the silicon-containing diisocyanate oligomer and isophorone diisocyanate are mixed in a weight ratio of 1:(1-2).

[0015] Further, in S3, the isocyanate mixture is added to polytetrahydrofuran ether diol 2000 in a molar ratio of isocyanate group to hydroxyl group (2-2.2):1.

[0016] Further, in step 3, the epoxy resin E-44, diluent isobornyl acrylate, silicon-containing polyurethane prepolymer, amino-functionalized graphene-silica composite filler, curing agent dicyandiamide, accelerator PN-23 are compounded in a weight ratio of 100:(20-25):(7-12):(1-2):(6-9):(2-3).

[0017] Further, in step 3, the coating amount of the mixed resin material on one side of the surface of the alumina fiber cloth is 120-300g / m 2 .

[0018] Further, in step 3, the coating amount of the mixed resin material on one side of the surface of the alumina fiber cloth is 120-300g / m 2 .

[0019] Further, in step 3, the hot-pressing composite temperature is 130-140 DEG C, and the hot-pressing composite pressure is 3-5 MPa.

[0020] Compared with the prior art, the present application has the advantages that the present application provides an alumina fiber reinforced mobile phone shell and a preparation process thereof, alumina fiber cloth is used as a reinforcing material, resin is coated on both surfaces of the alumina fiber cloth, and after curing, layering and hot-pressing processes, the mobile phone shell is obtained by painting the surface of the product.

[0021] The main creative point of the present application is that the resin on the surface of the alumina fiber cloth is modified, in the present application, the carbon-carbon double bond in the vinyl triethoxysilane is reacted with the amino group in the ethylenediamine through Michael addition reaction to synthesize a silicon-containing addition product with a secondary amine group, then the silicon-containing addition product is mixed with isophorone diisocyanate to synthesize a diisocyanate oligomer with a silicon-containing side chain through the reaction between the secondary amine group and the isocyanate group; the diisocyanate oligomer with a silicon-containing side chain is mixed with isophorone diisocyanate and reacts with polytetrahydrofuran ether diol 2000 to introduce the silicon-containing side chain into the polyurethane prepolymer; after the silicon-containing polyurethane prepolymer is mixed with the epoxy resin, the isocyanate groups of the polyurethane prepolymer are compatible with the epoxy resin through chemical reaction and physical blending, the flexible polyurethane prepolymer is introduced into the rigid epoxy resin, the toughness of the resin material is improved, and the impact resistance is improved; in the process of curing the resin into a film, the silicon atoms in the side chain of the polyurethane prepolymer migrate to the surface, and the surface tension of the adhesive film is reduced.

[0022] Meanwhile, in the present application, a layer of silica particles is prepared on the surface of the graphene oxide through a sol-gel method, and is modified by using silane coupling agent KH550 to introduce amino groups, thereby obtaining an aminated graphene-silica composite filler; the dispersion of the aminated graphene-silica composite filler and the epoxy resin is good, not only can improve the thermal conductivity and wear resistance, but also the amino groups on the surface of the aminated graphene-silica composite filler can be combined with the polyurethane prepolymer through chemical reaction to jointly toughen and modify the epoxy resin.

[0023] In addition, it needs to be pointed out that in the scheme of the present application, it is found that the molar ratio of ethylenediamine, vinyltriethoxysilane and isophorone diisocyanate is 1:2:(1.5-1.8), the silicon-containing diisocyanate oligomer is prepared, then mixed with isophorone diisocyanate according to the weight ratio of 1:(1-2), and then polytetrahydrofuran ether diol is used to synthesize polyurethane prepolymer, and the modification effect of the obtained polyurethane prepolymer on epoxy resin is better. This is mainly because the molecular weight of the silicon-containing diisocyanate oligomer should not be too high, when the amount of isophorone diisocyanate increases, the molecular weight of the prepared silicon-containing diisocyanate oligomer becomes larger, the viscosity of the prepared silicon-containing polyurethane prepolymer increases, and gel appears when the epoxy resin is modified, which affects the modification effect. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0025] Materials and sources used in the present application: polytetrahydrofuran ether diol 2000 and epoxy resin E-44 from Jining Baiyi Chemical Co., Ltd.; graphene oxide from Jiangsu Xianfeng Nanometer Material Technology Co., Ltd., product number XF002-3; alumina fiber cloth from Shandong Dongpeng Guofang New Material Co., Ltd., product number AFxx-FP20.

[0026] Example 1: An alumina fiber reinforced mobile phone shell and a preparation process thereof:

[0027] Step 1:

[0028] S1: Under ice bath conditions, vinyltriethoxysilane was added dropwise into ethylenediamine, and after the addition of vinyltriethoxysilane was completed, the temperature was controlled at 25℃ for 2h; under nitrogen environment, isophorone diisocyanate was added, dibutyltin dilaurate was used as catalyst, and the temperature was raised to 60℃, and reacted for 1h to obtain a silicon-containing diisocyanate oligomer; wherein the molar ratio of ethylenediamine, vinyltriethoxysilane and isophorone diisocyanate was 1:2:1.8;

[0029] S2: The silicon-containing diisocyanate oligomer and isophorone diisocyanate were mixed according to the weight ratio of 1:2 to obtain an isocyanate mixture;

[0030] S3: The isocyanate mixture and polytetrahydrofuran ether diol 2000 were vacuum dehydrated at 110 DEG C for 2h, and the isocyanate mixture was added to the polytetrahydrofuran ether diol 2000 in a molar ratio of isocyanate group to hydroxyl group of 2:1 under a nitrogen environment, with dibutyltin dilaurate as a catalyst, and the temperature was raised to 85 DEG C, and the reaction was carried out for 3h to obtain a silicon-containing polyurethane prepolymer;

[0031] Step 2:

[0032] 0.25g of graphene oxide was weighed, added with anhydrous ethanol, and ultrasonically dispersed for 30min; potassium hydroxide ethanol solution was added to adjust the pH to 8; it was heated to reflux at 80 DEG C in an oil bath for 8h, and then the pH value was adjusted to 7 with hydrochloric acid; after filtration, washing and drying, it was dispersed in an ethanol aqueous solution for 30min, then 20g of ammonia water was added, stirred for 10min, then 2.5g of tetraethyl orthosilicate was added, and the addition time was controlled for 15min, and the stirring reaction was carried out for 15h; after the reaction was completed, 0.05g of KH550 was added, and the stirring was continued for 6h; after filtration, washing and drying, an amino-functionalized graphene-silica composite filler was obtained;

[0033] Step 3:

[0034] The epoxy resin E-44, the diluent isobornyl acrylate, the silicon-containing polyurethane prepolymer, the amino-functionalized graphene-silica composite filler, the curing agent dicyandiamide, and the accelerator PN-23 were compounded in a weight ratio of 100:25:7:2:6:3, and stirring was performed to obtain a mixed resin material; the vacuum-dried alumina fiber cloth was taken, and the mixed resin material was coated on both sides of the surface thereof, and the single-sided coating amount was 200g / m 2 ; curing was carried out at 110 DEG C for 1h to obtain a prepreg; three layers of the prepreg were laminated, and a mobile phone shell substrate was obtained by hot pressing at 130 DEG C and 3MPa; the mobile phone shell substrate was painted on one side of the surface thereof, and curing was carried out to obtain a mobile phone shell.

[0035] Example 2: An alumina fiber-reinforced mobile phone shell and a preparation process thereof:

[0036] Step 1:

[0037] S1: Under ice bath conditions, vinyltriethoxysilane was added dropwise to ethylenediamine, and after the addition of vinyltriethoxysilane was completed, the temperature was controlled at 30 DEG C and the reaction was carried out for 2.5h; under a nitrogen environment, isophorone diisocyanate was added, with dibutyltin dilaurate as a catalyst, and the temperature was raised to 65 DEG C, and the reaction was carried out for 1.5h to obtain a silicon-containing diisocyanate oligomer; wherein the molar ratio of ethylenediamine, vinyltriethoxysilane, and isophorone diisocyanate was 1:2:1.8;

[0038] S2: The silicon-containing diisocyanate oligomer and isophorone diisocyanate were mixed in a weight ratio of 1:2 to obtain an isocyanate mixture;

[0039] S3: The isocyanate mixture and polytetrahydrofuran ether diol 2000 were vacuum dehydrated at 115 DEG C for 3h, and the isocyanate mixture was added to the polytetrahydrofuran ether diol 2000 in a molar ratio of isocyanate group to hydroxyl group of 2:1 under a nitrogen environment, with dibutyltin dilaurate as a catalyst, and the temperature was raised to 90 DEG C, and the reaction was carried out for 3.5h to obtain a silicon-containing polyurethane prepolymer;

[0040] Step 2:

[0041] 0.25g of graphene oxide was weighed, added with anhydrous ethanol, and ultrasonically dispersed for 30min; potassium hydroxide ethanol solution was used to adjust the pH to 9; it was heated under reflux at 85 DEG C in an oil bath for 9h, and then the pH value was adjusted to 7 with hydrochloric acid; after filtration, washing and drying, it was dispersed in an ethanol aqueous solution for 45min, then 20g of ammonia water was added, stirred for 15min, then 2.5g of tetraethyl orthosilicate was added, and the addition time was controlled for 20min, and the stirring reaction was carried out for 16h; after the reaction was completed, 0.05g of KH550 was added, and the stirring was continued for 7h; after filtration, washing and drying, an amino-functionalized graphene-silica composite filler was obtained;

[0042] Step 3:

[0043] The epoxy resin E-44, the diluent isobornyl acrylate, the silicon-containing polyurethane prepolymer, the amino-functionalized graphene-silica composite filler, the curing agent dicyandiamide, and the accelerator PN-23 were compounded in a weight ratio of 100:25:7:2:6:3, and stirring was performed to obtain a mixed resin material; the vacuum-dried alumina fiber cloth was taken, and the mixed resin material was coated on both sides of the surface thereof, and the single-sided coating amount was 200g / m 2 ; curing was carried out at 115 DEG C for 1.5h to obtain a prepreg; three layers of the prepreg were laminated, and a mobile phone shell substrate was obtained by hot pressing at 135 DEG C and 4MPa; the mobile phone shell substrate was painted on one side of the surface thereof, and curing was carried out to obtain a mobile phone shell.

[0044] Example 3: An alumina fiber-reinforced mobile phone shell and a preparation process thereof:

[0045] Step 1:

[0046] S1: Under ice bath conditions, vinyltriethoxysilane was added dropwise to ethylenediamine, and after the addition of the vinyltriethoxysilane was completed, the temperature was controlled at 35 DEG C for 3h; under a nitrogen environment, isophorone diisocyanate was added, with dibutyltin dilaurate as a catalyst, and the temperature was raised to 70 DEG C, and the reaction was carried out for 2h to obtain a silicon-containing diisocyanate oligomer; wherein the molar ratio of ethylenediamine, vinyltriethoxysilane, and isophorone diisocyanate was 1:2:1.8;

[0047] S2: mixing the silicon-containing diisocyanate oligomer and isophorone diisocyanate at a weight ratio of 1:2 to obtain an isocyanate mixture;

[0048] S3: vacuum dehydration of the isocyanate mixture and polytetrahydrofuran ether glycol 2000 at 120℃ for 4h, under a nitrogen environment, adding the isocyanate mixture to the polytetrahydrofuran ether glycol 2000 at an isocyanate group and hydroxyl group molar ratio of 2:1, using dibutyltin dilaurate as a catalyst, warming to 90℃, and reacting for 4h to obtain a silicon-containing polyurethane prepolymer;

[0049] Step 2:

[0050] Step 2:

[0051] Step 3:

[0052] The epoxy resin E-44, the diluent isobornyl acrylate, the silicon-containing polyurethane prepolymer, the amino-functionalized graphene-silica composite filler, the curing agent dicyandiamide, and the accelerator PN-23 are compounded at a weight ratio of 100:25:7:2:6:3, and stirring is performed to obtain a mixed resin material. A vacuum-dried alumina fiber cloth is taken, and the mixed resin material is coated on both surfaces of the alumina fiber cloth. The single-sided coating amount is 200g / m 2 ; curing at 120℃ for 2h to obtain a prepreg; stacking 3 layers of the prepreg, and hot pressing at 140℃ and 5MPa to obtain a mobile phone shell substrate; spraying paint on one surface of the mobile phone shell substrate and curing to obtain a mobile phone shell.

[0053] Example 4: An alumina fiber-reinforced mobile phone shell and a preparation process thereof:

[0054] Step 1:

[0055] S1: under ice bath conditions, adding vinyltriethoxysilane dropwise to ethylenediamine, and after the addition of the vinyltriethoxysilane is completed, controlling the temperature to be 25℃ and reacting for 2h; under a nitrogen environment, adding isophorone diisocyanate, using dibutyltin dilaurate as a catalyst, warming to 60℃, and reacting for 1h to obtain a silicon-containing diisocyanate oligomer; wherein the molar ratio of ethylenediamine, vinyltriethoxysilane, and isophorone diisocyanate is 1:2:1.8;

[0056] S2: mixing the silicon-containing diisocyanate oligomer and isophorone diisocyanate at a weight ratio of 1:2 to obtain an isocyanate mixture;

[0057] S3: vacuum dehydrating the isocyanate mixture and polytetrahydrofuran ether diol 2000 at 110°C for 2h, adding the isocyanate mixture to the polytetrahydrofuran ether diol 2000 at an isocyanate group and hydroxyl group molar ratio of 2:1 under a nitrogen environment, using dibutyltin dilaurate as a catalyst, and heating to 85°C for 3h to obtain a silicon-containing polyurethane prepolymer;

[0058] Step 2:

[0059] 0.25g of graphene oxide was weighed and added to anhydrous ethanol and ultrasonically dispersed for 30min; potassium hydroxide ethanol solution was added to adjust the pH to 8; the oil bath was heated to 80°C and refluxed for 8h, then hydrochloric acid was added to adjust the pH to 7, and then the mixture was filtered, washed with water and dried; the graphene oxide was dispersed in an ethanol aqueous solution for 30min, then 20g of ammonia water was added, and the mixture was stirred for 10min; then 2.5g of tetraethyl orthosilicate was added, and the addition time was controlled to be 15min; the mixture was stirred for 15h; then 0.05g of KH550 was added, and the mixture was stirred for another 6h; the mixture was filtered, washed with water and dried to obtain an amino-functionalized graphene-silica composite filler;

[0060] Step 3:

[0061] Epoxy resin E-44, diluent isobornyl acrylate, silicon-containing polyurethane prepolymer, amino-functionalized graphene-silica composite filler, curing agent dicyandiamide, and accelerator PN-23 were compounded at a weight ratio of 100:25:9:2:6:3, and the mixture was stirred to obtain a mixed resin material; a vacuum-dried alumina fiber cloth was taken, and the mixed resin material was coated on both surfaces of the alumina fiber cloth, and the single-sided coating amount was 200g / m 2 ; the mixture was cured at 110°C for 1h to obtain a prepreg; three layers of the prepreg were stacked, and a mobile phone shell substrate was obtained by hot pressing at 130°C and 3MPa; the mobile phone shell substrate was painted on one side surface and cured to obtain a mobile phone shell.

[0062] Example 5: An alumina fiber-reinforced mobile phone shell and a preparation process thereof:

[0063] Step 1:

[0064] S1: under ice bath conditions, vinyltriethoxysilane was added dropwise into ethylenediamine, after the addition of vinyltriethoxysilane was completed, the temperature was controlled at 30℃ for 1.5h; under nitrogen environment, isophorone diisocyanate was added, with dibutyltin dilaurate as catalyst, the temperature was raised to 65℃, and reacted for 1.5h to obtain a silicon-containing diisocyanate oligomer; wherein the molar ratio of ethylenediamine, vinyltriethoxysilane and isophorone diisocyanate was 1:2:1.8;

[0065] S2: the silicon-containing diisocyanate oligomer and isophorone diisocyanate were mixed in a weight ratio of 1:2 to obtain an isocyanate mixture;

[0066] S3: the isocyanate mixture and polytetrahydrofuran ether glycol 2000 were vacuum dehydrated at 115℃ for 3h, under nitrogen environment, the isocyanate mixture was added into polytetrahydrofuran ether glycol 2000 according to the molar ratio of isocyanate group to hydroxyl group of 2:1, with dibutyltin dilaurate as catalyst, the temperature was raised to 90℃, and reacted for 3.5h to obtain a silicon-containing polyurethane prepolymer;

[0067] Step 2:

[0068] 0.25g of graphene oxide was weighed, added with anhydrous ethanol, and ultrasonically dispersed for 30min; potassium hydroxide ethanol solution was used to adjust the pH to 9; oil bath heating reflux was carried out at 85℃ for 9h, then hydrochloric acid was used to adjust the pH to 7, and after suction filtration, water washing and drying, it was dispersed in an ethanol aqueous solution for 60min, then 20g of ammonia water was added, stirred for 15min, then 2.5g of tetraethyl orthosilicate was added, the addition time was controlled for 15min, and the stirring reaction was carried out for 16h; after the reaction was completed, 0.05g of KH550 was added, and the stirring was continued for 7h, and after suction filtration, water washing and drying, an aminated graphene-silica composite filler was obtained;

[0069] Step 3:

[0070] Epoxy resin E-44, diluent isobornyl acrylate, silicon-containing polyurethane prepolymer, aminated graphene-silica composite filler, curing agent dicyandiamide and accelerator PN-23 were compounded in a weight ratio of 100:25:10:2:6:3, and stirring was carried out to obtain a mixed resin material; vacuum-dried alumina fiber cloth was taken, and the mixed resin material was coated on both sides of the surface, and the single-sided coating amount was 200g / m 2 ; curing was carried out at 115℃ for 2h to obtain a prepreg; 3 layers of prepreg were laminated, and a mobile phone shell substrate was obtained by hot pressing at 140℃ and 4MPa; paint was sprayed on one side surface of the mobile phone shell substrate, and curing was carried out to obtain a mobile phone shell.

[0071] Example 6: an alumina fiber reinforced mobile phone shell and a preparation process thereof:

[0072] Step 1:

[0073] S1: under ice bath conditions, vinyl triethoxysilane was added dropwise into ethylenediamine, after the addition of vinyl triethoxysilane was completed, the temperature was controlled at 35℃ for 3h; under nitrogen environment, isophorone diisocyanate was added, with dibutyltin dilaurate as catalyst, the temperature was raised to 70℃, and reacted for 2h to obtain a silicon-containing diisocyanate oligomer; wherein the molar ratio of ethylenediamine, vinyl triethoxysilane and isophorone diisocyanate was 1:2:1.8;

[0074] S2: the silicon-containing diisocyanate oligomer and isophorone diisocyanate were mixed in a weight ratio of 1:2 to obtain an isocyanate mixture;

[0075] S3: the isocyanate mixture and polytetrahydrofuran ether glycol 2000 were vacuum dehydrated at 120℃ for 4h, under nitrogen environment, the isocyanate mixture was added into polytetrahydrofuran ether glycol 2000 according to the molar ratio of isocyanate group to hydroxyl group of 2:1, with dibutyltin dilaurate as catalyst, the temperature was raised to 90℃, and reacted for 4h to obtain a silicon-containing polyurethane prepolymer;

[0076] Step 2:

[0077] 0.25g of graphene oxide was weighed, added with anhydrous ethanol, and ultrasonically dispersed for 30min; potassium hydroxide ethanol solution was used to adjust the pH to 10; oil bath heating reflux was carried out at 90℃ for 10h, then hydrochloric acid was used to adjust the pH to 7, and after suction filtration, water washing and drying, it was dispersed in an ethanol aqueous solution for 60min, then 20g of ammonia water was added, stirred for 15min, 2.5g of tetraethyl orthosilicate was added, the addition time was controlled for 20min, and stirring reaction was carried out for 18h; after the reaction was completed, 0.05g of KH550 was added, and stirring was continued for 8h, and after suction filtration, water washing and drying, an aminated graphene-silica composite filler was obtained;

[0078] Step 3:

[0079] Epoxy resin E-44, diluent isobornyl acrylate, silicon-containing polyurethane prepolymer, aminated graphene-silica composite filler, curing agent dicyandiamide and accelerator PN-23 were compounded in a weight ratio of 100:25:12:2:6:3, and stirring was carried out to obtain a mixed resin material; vacuum dried alumina fiber cloth was taken, and the mixed resin material was coated on both sides of the surface, the single-sided coating amount was 200g / m 2 ; curing was carried out at 120℃ for 2h to obtain a prepreg; 3 layers of prepreg were laminated, and a mobile phone shell substrate was obtained by hot pressing at 140℃ and 5MPa; paint was sprayed on one side surface of the mobile phone shell substrate, and curing was carried out to obtain a mobile phone shell.

[0080] Comparative Example 1: no silicon-containing polyurethane prepolymer was added, and the remaining parameters were the same as those of Example 1.

[0081] Step 1:

[0082] Take 0.25g of graphene oxide, add anhydrous ethanol, ultrasonic dispersion for 30min; adjust the pH to 8 with potassium hydroxide ethanol solution; heat reflux at 80℃ in oil bath for 8h, then adjust the pH to 7 with hydrochloric acid, and then filter, wash with water and dry; disperse in ethanol water solution for 30min, then add 20g of ammonia water, stir for 10min, then add 2.5g of tetraethyl orthosilicate, control the adding time for 15min, and stir for 15h; after the reaction, add 0.05g of KH550, continue to stir for 6h, filter, wash with water and dry to obtain amino-functionalized graphene-silica composite filler;

[0083] Step 2:

[0084] Mix epoxy resin E-44, diluent isobornyl acrylate, amino-functionalized graphene-silica composite filler, curing agent dicyandiamide, and accelerator PN-23 in a weight ratio of 100:25:2:6:3 to obtain a mixed resin material; take the vacuum-dried alumina fiber cloth and coat the mixed resin material on both sides of the surface, with a single-sided coating amount of 200g / m 2 ; cure at 110℃ for 1h to obtain a semi-cured sheet; stack 3 layers of semi-cured sheets, and hot-press composite at 130℃ and 3MPa to obtain a mobile phone shell substrate; spray paint on one side of the mobile phone shell substrate and cure to obtain a mobile phone shell.

[0085] Comparative Example 2: No amino-functionalized graphene-silica composite filler is added, and the remaining parameters are the same as those of Example 2.

[0086] Step 1:

[0087] S1: Under ice bath conditions, add vinyl triethoxysilane dropwise to ethylenediamine, and after the addition of vinyl triethoxysilane is completed, control the temperature to be 30℃ and react for 2.5h; under nitrogen environment, add isophorone diisocyanate, and use dibutyltin dilaurate as catalyst, and heat to 65℃, and react for 1.5h to obtain a silicon-containing diisocyanate oligomer; wherein the molar ratio of ethylenediamine, vinyl triethoxysilane and isophorone diisocyanate is 1:2:1.8;

[0088] S2: Mix the silicon-containing diisocyanate oligomer and isophorone diisocyanate in a weight ratio of 1:2 to obtain an isocyanate mixture;

[0089] S3: The isocyanate mixture and polytetrahydrofuran ether diol 2000 were vacuum dehydrated at 115°C for 3h, and then the isocyanate mixture was added to the polytetrahydrofuran ether diol 2000 under a nitrogen environment according to a molar ratio of isocyanate groups to hydroxyl groups of 2:1, a dibutyl tin dilaurate was used as a catalyst, the temperature was raised to 90°C, and the reaction was carried out for 3.5h to obtain a silicon-containing polyurethane prepolymer;

[0090] Step 2:

[0091] The epoxy resin E-44, the diluent isobornyl acrylate, the silicon-containing polyurethane prepolymer, the curing agent dicyandiamide, and the accelerator PN-23 were compounded according to a weight ratio of 100:25:7:6:3, and stirring was performed to obtain a mixed resin material; a vacuum-dried alumina fiber cloth was taken, and the mixed resin material was coated on both sides of the alumina fiber cloth, and the single-side coating amount was 200g / m 2 ; curing was performed at 115°C for 1.5h to obtain a prepreg; three layers of the prepreg were stacked, and a mobile phone shell substrate was obtained by hot pressing at 135°C and 4MPa; and the mobile phone shell substrate was painted on one side and cured to obtain a mobile phone shell.

[0092] Comparative Example 3: The amount of isophorone diisocyanate in S1 was increased, and the other parameters were the same as those in Example 3.

[0093] Step 1:

[0094] S1: Under ice bath conditions, vinyl triethoxysilane was added dropwise to ethylenediamine, and after the addition of the vinyl triethoxysilane was completed, the temperature was controlled at 35°C for 3h; under a nitrogen environment, isophorone diisocyanate was added, a dibutyl tin dilaurate was used as a catalyst, the temperature was raised to 70°C, and the reaction was carried out for 2h to obtain a silicon-containing diisocyanate oligomer; wherein the molar ratio of ethylenediamine, vinyl triethoxysilane, and isophorone diisocyanate was 1:2:2;

[0095] S2: The silicon-containing diisocyanate oligomer and isophorone diisocyanate were mixed according to a weight ratio of 1:2 to obtain an isocyanate mixture;

[0096] S3: The isocyanate mixture and polytetrahydrofuran ether diol 2000 were vacuum dehydrated at 120°C for 4h, and then the isocyanate mixture was added to the polytetrahydrofuran ether diol 2000 under a nitrogen environment according to a molar ratio of isocyanate groups to hydroxyl groups of 2:1, a dibutyl tin dilaurate was used as a catalyst, the temperature was raised to 90°C, and the reaction was carried out for 4h to obtain a silicon-containing polyurethane prepolymer;

[0097] Step 2:

[0098] Take 0.25 g of graphene oxide, add anhydrous ethanol, ultrasonic dispersion for 30 min; adjust to pH 10 with potassium hydroxide ethanol solution; heat under oil bath at 90℃ for 10 h, then adjust the pH value to 7 with hydrochloric acid, suction filtration, water washing, drying, then disperse in ethanol water solution for 60 min, then add 20 g of ammonia water, stir for 15 min, then add 2.5 g of tetraethyl orthosilicate, control the adding time for 20 min, stir for 18 h; after the reaction, add 0.05 g of KH550, continue to stir for 8 h, suction filtration, water washing, drying to obtain amino-functionalized graphene-silica composite filler;

[0099] Step 3:

[0100] The epoxy resin E-44, diluent isobornyl acrylate, silicon-containing polyurethane prepolymer, amino-functionalized graphene-silica composite filler, curing agent dicyandiamide, accelerator PN-23 are compounded according to the weight ratio of 100:25:7:2:6:3, and the mixed resin material is obtained by stirring; take the vacuum dried alumina fiber cloth, and coat the mixed resin material on both sides of the surface, and the single-sided coating amount is 200 g / m 2 ; curing at 120℃ for 2h to obtain a prepreg; stacking 3 layers of prepreg, hot pressing at 140℃ and 5MPa to obtain a mobile phone shell substrate; spraying paint on one side surface of the mobile phone shell substrate and curing to obtain a mobile phone shell.

[0101] Experiment: the mobile phone shells prepared in examples 1-6 and comparative examples 1-3 are tested for performance, and the experimental results are shown in the following table. Among them:

[0102] Thermal performance: according to ASTM D5470, the sample is made into 40mm×10mm×2mm, and the thermal conductivity tester is used for testing;

[0103] Hydrophobic performance: 4μL water droplet is used for contact angle test;

[0104] Wear resistance: AATCC standard cotton cloth is used as the wear medium, the load weight is 200g, and one way is regarded as a wear cycle, and the cycle is 500 times. The wear resistance of the coating is evaluated by measuring the water contact angle;

[0105] Impact strength: according to GB / T 1843-2008, the sample is made into 80mm×10mm×2mm, and the impact energy is 5.5J.

[0106]

[0107]

[0108] Conclusion: The data of Examples 1-6 show that the mobile phone shell prepared by the present application has strong wear resistance, good heat dissipation effect, high impact strength and good waterproof performance. The data of Example 1 and Comparative Example 1 show that the addition of the silicon-containing polyurethane prepolymer can give the mobile phone shell good hydrophobic performance and also improve the impact resistance; the data of Example 2 and Comparative Example 2 show that the addition of the amino-functionalized graphene-silica composite filler can improve the wear resistance and heat conduction performance of the material, and also improve the impact resistance; the data of Example 3 and Comparative Example 3 show that increasing the amount of isophorone diisocyanate in S1 results in an increase in the molecular weight of the silicon-containing diisocyanate oligomer, which leads to an increase in the viscosity of the silicon-containing polyurethane prepolymer, and a small amount of gel is generated during the modification of the epoxy resin, so that the performance of the prepared mobile phone shell is reduced.

[0109] Finally, it should be noted that: the above only for the preferred embodiments of the present application, and not for limiting the present application, although the foregoing detailed description of the present application is made with reference to the foregoing embodiments, for those skilled in the art, it still can be modified, or the equivalent replacement of the technical solutions recorded in the foregoing embodiments. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A process for the preparation of an alumina fiber reinforced cell phone case, characterized by: Comprising the following steps: Step 1: The isocyanate mixture and polytetrahydrofuran ether glycol 2000 are vacuum dehydrated at 110-120 DEG C for 2-4h, the isocyanate mixture is added to the polytetrahydrofuran ether glycol 2000 under nitrogen environment, dibutyltin dilaurate is used as catalyst, the temperature is raised to 85-90 DEG C, and the reaction is carried out for 3-4h to obtain a silicon-containing polyurethane prepolymer; Step 2: The epoxy resin E-44, the diluent isobornyl acrylate, the silicon-containing polyurethane prepolymer, the amino-functionalized graphene-silica composite filler, the curing agent dicyandiamide and the accelerator PN-23 are compounded to obtain a mixed resin material; the vacuum-dried alumina fiber cloth is coated with the mixed resin material on both sides, and is heated and cured to obtain a prepreg; a plurality of prepregs are laminated and hot-pressed to obtain a mobile phone shell substrate; the mobile phone shell substrate is painted on one side and is cured to obtain a mobile phone shell. The isocyanate mixture is prepared by mixing the silicon-containing diisocyanate oligomer and isophorone diisocyanate at a weight ratio of 1:(1-2). The silicon-containing diisocyanate oligomer is prepared by adding vinyltriethoxysilane dropwise to ethylenediamine under ice bath conditions, controlling the temperature to be 25-35 DEG C for 2-3h after the addition of vinyltriethoxysilane is completed, and adding isophorone diisocyanate under nitrogen environment, using dibutyltin dilaurate as catalyst, raising the temperature to 60-70 DEG C, and reacting for 1-2h. The molar ratio of ethylenediamine, vinyltriethoxysilane and isophorone diisocyanate is 1:2:(1.5-1.8).

2. The process for preparing an alumina fiber reinforced cell phone case according to claim 1, characterized in that: In step 2, the amino-functionalized graphene-silica composite filler is prepared by weighing 0.25-0.3 parts of graphene oxide, adding anhydrous ethanol, and ultrasonic dispersion for 30min; adjusting the pH to 8-10 with potassium hydroxide ethanol solution; heating under oil bath at 80-90 DEG C for 8-10h, then adjusting the pH to 7 with hydrochloric acid, and then performing suction filtration, water washing and drying, and then dispersing in an ethanol aqueous solution for 30-60min, then adding 15-20 parts of ammonia water, stirring for 10-15min, then adding 2-2.5 parts of tetraethyl orthosilicate, controlling the addition time to be 15-20min, and stirring for 15-18h; after the reaction is completed, adding 0.03-0.05 parts of KH550, and continuing to stir for 6-8h, to obtain the amino-functionalized graphene-silica composite filler.

3. The process for preparing an alumina fiber reinforced cell phone case according to claim 1, wherein: In step 2, the epoxy resin E-44, the diluent isobornyl acrylate, the silicon-containing polyurethane prepolymer, the amino-functionalized graphene-silica composite filler, the curing agent dicyandiamide and the accelerator PN-23 are compounded at a weight ratio of 100:(20-25):(7-12):(1-2):(6-9):(2-3).

4. The process for preparing an alumina fiber reinforced cell phone case according to claim 1, wherein: In Step 2, the coating amount of the mixed resin material on one side surface of the alumina fiber cloth is 120 to 300 g / m 2 .

5. The process for preparing an alumina fiber reinforced cell phone case according to claim 1, wherein: In step 2, the curing is carried out at 110-120 DEG C for 1-2h to obtain the prepreg.

6. The process for preparing an alumina fiber reinforced cell phone case according to claim 1, wherein: In step 2, the hot-pressing temperature is 130-140 DEG C, and the hot-pressing pressure is 3-5MPa.

7. The mobile phone shell prepared by the preparation process according to any one of claims 1-6.

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