Modified thin film material and preparation method of thin film material

Abstract

The invention relates to the technical field of high polymer materials, in particular to a modified thin film material and a preparation method of the thin film material. The modified thin film material is prepared from the following raw materials in parts by weight: 60-90 parts of polyethylene glycol terephthalate resin, 5-20 parts of reinforcing filler, 3-10 parts of functional filler, 2-5 parts of plasticizer and 1-4 parts of antioxidant. The reinforcing filler is composed of modified nano-montmorillonite and silane-treated calcium carbonate and is uniformly dispersed through ball milling, the mechanical property of the film can be enhanced, the tensile strength and toughness can be improved, the functional filler is formed by compounding hydroxylated graphene and nano-silver particles, the film is endowed with antibacterial and conductive functions, the film is optimized and dispersed through the silane coupling agent, and the mechanical property of the film is improved. Under the synergistic effect of all the materials, the thickness deviation of the film is smaller than or equal to + / -5%, the tensile strength is larger than or equal to 80 MPa, the film has excellent mechanical performance and functionality, and the problems that in the prior art, filler dispersion is poor, and performance synergy is insufficient are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high molecular materials, in particular to a modified film material and a preparation method of the film material. BACKGROUND

[0002] Polyethylene terephthalate (PET) film is widely used in packaging, electronics, optics and other fields due to its good mechanical properties, chemical stability and transparency.

[0003] In the prior art, the conventional reinforcing filler has poor compatibility with the polyethylene terephthalate resin and is prone to agglomeration in the resin matrix, which cannot be uniformly dispersed, resulting in limited improvement of the mechanical properties of the film, and even the toughness of the film is reduced due to stress concentration, and it is difficult to realize the performance synergy of high strength and high toughness, the graphene in the functional filler is prone to agglomeration, and cannot play the role of reinforcing and conducting in the film if not effectively modified by hydroxylation, the dispersion of nano-silver particles is poor, and the antibacterial and electrical properties are easily reduced due to agglomeration, and the interface interaction with other fillers and resins is weak, and it is difficult to synergistically endow the film with multifunctionality.

[0004] Therefore, the present application provides a modified film material and a preparation method of the film material. SUMMARY

[0005] The present application aims to provide a modified film material and a preparation method of the film material, the modified film material prepared by the present application not only has good strength performance, but also has good elongation at break and antibacterial rate, and the thickness deviation is low, the overall performance is more consistent, and the yield is higher.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a modified film material comprising the following raw materials by weight: 60-90 parts of polyethylene terephthalate resin, 5-20 parts of reinforcing filler, 3-10 parts of functional filler, 2-5 parts of plasticizer, and 1-4 parts of antioxidant.

[0007] The reinforcing filler is composed of modified nano-montmorillonite and silane-treated calcium carbonate.

[0008] The functional filler is prepared by mixing hydroxylated graphene and nano-silver particles.

[0009] Preferably, the modifier of the modified nano-montmorillonite is cetyl trimethyl ammonium bromide, the amount of the modifier is 10-20% of the mass of the nano-montmorillonite, and the modification method is as follows: the raw material montmorillonite is crushed and sieved, washed with deionized water to remove impurities, and dried at 80-100°C for 4-6h; the dried montmorillonite is dispersed in deionized water, and the solid-liquid ratio is 1:(10-20); a suspension is formed by stirring; the modifier is added; stirring is performed at 70-90°C for 2-4h; after the reaction is completed, the product is centrifuged and washed with deionized water until there is no bromide ion; vacuum drying is performed at 80-100°C for 8-12h; and the modified nano-montmorillonite is obtained after grinding.

[0010] Preferably, the silane coupling agent in the silane-treated calcium carbonate is KH550, and the amount of the silane coupling agent is 1-3% of the mass of the calcium carbonate; the treatment method is as follows: the calcium carbonate is crushed to nanoscale, dried at 100-120°C for 2-4h to remove surface moisture; KH550 is dissolved in anhydrous ethanol, and the volume ratio of silane to ethanol is 1:(5-10); the PH is adjusted to 3-5; hydrolysis is performed by stirring for 15-30min to obtain an activated silane solution; the treated calcium carbonate is added to a high-speed mixer with a rotation speed of 500-1000r / min, and the activated silane solution is sprayed; stirring is performed at 60-80°C for 30-60min to enable the silane coupling agent to be combined on the surface of the calcium carbonate by a chemical bond; and finally, vacuum drying is performed at 80-100°C for 2-4h to obtain the silane-treated calcium carbonate.

[0011] Preferably, the preparation method of the reinforcing filler is as follows: the modified nano-montmorillonite and the silane-treated calcium carbonate are weighed according to a mass ratio of (3-5):(1-2), and then put into a horizontal stirring ball mill, with zirconium oxide balls as the ball milling medium, a ball-to-material mass ratio of (4-6):1, and a mill rotation speed of 150-250r / min; the grinding treatment is performed for 1.5-3h; after the medium is removed through sieving, the uniformly dispersed reinforcing filler is obtained.

[0012] Preferably, the preparation method of the hydroxylated graphene is as follows: graphite powder, concentrated sulfuric acid, and sodium nitrate are mixed according to a mass ratio of (10-15):(200-250):(2-5), and then potassium permanganate is slowly added at 0-5°C, with a mass ratio of potassium permanganate to graphite powder of (3-5):1; stirring is performed for 2-4h, and then the temperature is increased to 30-40°C for reaction for 1-2h; deionized water is added and the temperature is increased to 90-100°C for reaction for 30-60min; after the reaction is completed, hydrogen peroxide solution is added to reduce the residual oxidizing agent; after centrifugal separation, the product is washed with dilute hydrochloric acid and deionized water alternately until it is neutral; and the hydroxylated graphene is obtained through freeze-drying and ultrasonic peeling, with a sheet thickness of 0.8-2nm and a carbon atom ratio of (8-12):1.

[0013] Preferably, the preparation method of the nano-silver particles is as follows: silver nitrate is dissolved in deionized water to prepare a 0.01-0.05 mol / L solution, 0.5-2% polyvinylpyrrolidone by mass fraction is added as a dispersant, 0.05-0.2 mol / L sodium borohydride reducing agent is added drop by drop under stirring, the mass ratio of silver nitrate to sodium borohydride is 1:(2-4), the reaction temperature is 20-30°C, the reaction time is 30-60 min, and after the reaction, the nano-silver particles are obtained through centrifugation, deionized water washing and vacuum drying, the particle size is 20-50 nm, and the dispersity is ≥90%.

[0014] Preferably, the hydroxylated graphene and the nano-silver particles are weighed according to the mass ratio (3-5):(1-2), deionized water is added to prepare a suspension with a solid content of 5-10%, the suspension is dispersed under an ultrasonic frequency of 20-40 kHz and a power of 300-500 W for 30-60 min, then 1-3% silane coupling agent KH570 by mass of the suspension is added, and stirring reaction is carried out at 50-70°C for 1-2 h, and the functional filler is prepared through centrifugation and vacuum drying at 60-80°C for 4-6 h, and the agglomerated particle size is ≤100 nm.

[0015] Preferably, the plasticizer is one of dimethyl phthalate, dioctyl adipate or epoxy soybean oil; and the antioxidant is one of antioxidant 1010, antioxidant 168 or antioxidant 1076.

[0016] Preferably, the intrinsic viscosity of the polyethylene terephthalate resin is 0.65-0.85 dL / g, the carboxyl end group content is ≤20 mmol / kg, and the ash content is ≤0.1%.

[0017] The preparation method of the modified film material comprises the following steps: the polyethylene terephthalate resin is placed in a vacuum drying box at 120-140°C and dried for 3-5 h to remove water; the dried polyethylene terephthalate resin, the reinforcing filler, the functional filler, the plasticizer and the antioxidant are weighed according to the weight parts and put into a high-speed mixer to mix at 80-100°C and a rotation speed of 300-500 r / min for 15-30 min to obtain a premix; the premix is added into a double-screw extruder, the extrusion temperature is set, the feeding section is 240-260°C, the melting section is 275-295°C, the homogenizing section is 265-285°C, the screw rotation speed is 120-220 r / min, and the modified film material is prepared through extrusion, film casting, cooling and setting, and winding, the casting roll temperature is 50-70°C, the cooling roll temperature is 20-30°C, the tension is 5-10 N, the thickness deviation is ≤±5%, and the tensile strength is ≥80 MPa.

[0018] Compared with the prior art, the modified film material has the following beneficial effects:

[0019] 1. The application, the modified nanometer montmorillonite is modified by cetyltrimethylammonium bromide intercalation, the silane treated calcium carbonate is connected by the interface of KH500, and the two are uniformly dispersed by ball milling process, the synergistic effect of the two fillers can effectively transfer and disperse stress, overcome the limitation of single filler reinforcement effect, greatly improve the mechanical support ability of the film, solve the problem that the traditional reinforcing filler is easy to agglomerate and the interface with the resin is weak, which leads to the difficulty in considering the strength and toughness of the film, and give the film better anti-deformation and anti-cracking performance.

[0020] 2. The application, the functional seasoning is composed of hydroxylated graphene and nano silver particles, which is dispersed in the interface by KH570 silane coupling agent, the hydroxylated graphene provides mechanical enhancement, conductivity and other basic functions for the film by its sheet structure and excellent performance, and the nano silver plays the function of antibacterial and other functional characteristics, and the two are uniformly dispersed and closely combined with the resin under the action of the coupling agent, and the synergistic effect makes the film have mechanical strengthening and functional giving ability at the same time, which breaks through the bottleneck of poor dispersion of traditional functional filler, difficult to stabilize the function, and difficult to improve the mechanical properties.

[0021] 3. The application, the polyethylene terephthalate, reinforcing filler, functional filler, plasticizer and antioxidant form a synergistic system, the resin ensures the basic stability, the plasticizer optimizes the processing and flexibility, the antioxidant delays aging, and each filler is uniformly dispersed and interface adapted by modification and process control, under the synergistic effect of multiple components, the compatibility between components in the prior art is poor, and the performance is restricted by each other, so that the film is simultaneously improved in mechanical properties, function, processing stability and the like. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0023] It should be noted that the raw materials used in the following experiments are all commercially available.

[0024] Example 1: Modified film material, comprising the following raw materials by weight: 60 parts of polyethylene terephthalate resin, 5 parts of reinforcing filler, 3 parts of functional filler, 2 parts of plasticizer, and 1 part of antioxidant;

[0025] The reinforcing filler is composed of modified nanometer montmorillonite and silane treated calcium carbonate.

[0026] The functional filler is prepared by mixing hydroxylated graphene and nano silver particles.

[0027] The modifier of the modified nano montmorillonite is cetyl trimethyl ammonium bromide, and the amount of the modifier is 10% of the mass of the nano montmorillonite. The modification method is as follows: the raw material montmorillonite is crushed and sieved, washed with deionized water to remove impurities, and dried at 80°C under vacuum for 4h. The dried montmorillonite is dispersed in deionized water with a solid-liquid ratio of 1:10, and stirred to form a suspension. The modifier is added and stirred at 70°C for 2h. After the reaction is completed, the product is centrifuged and washed with deionized water until there is no bromide ion. The product is dried at 80°C under vacuum for 8h. After drying, the modified nano montmorillonite is obtained by grinding.

[0028] The silane coupling agent in the silane-treated calcium carbonate is KH550, and the amount of the silane coupling agent is 1% of the mass of the calcium carbonate. The treatment method is as follows: the calcium carbonate is crushed to nanoscale, dried at 100°C for 2h to remove surface moisture, and then KH550 is dissolved in anhydrous ethanol with a volume ratio of silane to ethanol of 1:5. The pH is adjusted to 3, and the silane solution is hydrolyzed by stirring for 15min to obtain an activated silane solution. The treated calcium carbonate is added to a high-speed mixer with a rotation speed of 500r / min, and the activated silane solution is sprayed. The mixture is stirred at 60°C for 30min to allow the silane coupling agent to be chemically bonded to the surface of the calcium carbonate. Finally, the silane-treated calcium carbonate is obtained by drying at 80°C under vacuum for 2h.

[0029] The preparation method of the reinforcing filler is as follows: the modified nano montmorillonite and the silane-treated calcium carbonate are weighed according to a mass ratio of 3:1, and then put into a horizontal stirring ball mill with zirconia balls as the ball milling medium. The mass ratio of the ball to the material is 4:1, and the rotation speed of the mill is controlled at 150r / min. The grinding treatment is carried out for 1.5h. After screening and removing the medium, the uniformly dispersed reinforcing filler is obtained.

[0030] The preparation method of the hydroxylated graphene is as follows: graphite powder, concentrated sulfuric acid and sodium nitrate are mixed according to a mass ratio of 10:200:2, and potassium permanganate is slowly added at 0°C. The mass ratio of potassium permanganate to graphite powder is 3:1. The mixture is stirred for 2h, and then heated to 30°C for 1h. Deionized water is added and heated to 90°C for 30min. After the reaction is completed, hydrogen peroxide solution is added to reduce the remaining oxidizing agent. After centrifugal separation, the product is washed with dilute hydrochloric acid and deionized water alternately until it is neutral. The hydroxylated graphene is obtained by freeze-drying and ultrasonic peeling. The sheet thickness of the hydroxylated graphene is 0.8nm, and the carbon atom ratio is 8:1.

[0031] The preparation method of the nano silver particles is as follows: silver nitrate is dissolved in deionized water to prepare a 0.01mol / L solution, and 0.5% of polyvinylpyrrolidone by mass is added as a dispersant. Under stirring, 0.05mol / L sodium borohydride reducing agent is added dropwise. The mass ratio of silver nitrate to sodium borohydride is 1:2. The reaction temperature is 20°C, and the reaction time is 30min. After the reaction, the nano silver particles are obtained by centrifugation, washing with deionized water and vacuum drying. The particle size of the nano silver particles is 20nm, and the dispersity is ≥90%.

[0032] The functional filler is prepared by weighing hydroxylated graphene and nano-silver particles in a mass ratio of 3:1, adding deionized water to prepare a suspension with a solid content of 5%, dispersing for 30 min under an ultrasonic frequency of 20 kHz and a power of 300 W, then adding 1% of the mass of the suspension of silane coupling agent KH570, stirring and reacting at 50°C for 1 h, and then centrifuging, vacuum drying at 60°C for 4 h to obtain the functional filler with an agglomerated particle size of ≤100 nm.

[0033] The plasticizer is dimethyl phthalate, and the antioxidant is antioxidant 1010.

[0034] The intrinsic viscosity of the polyethylene terephthalate resin is 0.65 dL / g, the carboxyl end group content is ≤20 mmol / kg, and the ash content is ≤0.1%.

[0035] The modified film material is prepared by the following steps: drying the polyethylene terephthalate resin in a vacuum drying oven at 120°C for 3 h to remove water; weighing the dried polyethylene terephthalate resin, reinforcing filler, functional filler, plasticizer, and antioxidant by weight parts, and feeding them into a high-speed mixer to mix at 80°C and a rotation speed of 300 r / min for 15 min to obtain a premix; feeding the premix into a twin-screw extruder, setting the extrusion temperature, feeding at 240°C, melting at 275°C, homogenizing at 265°C, and rotating the screw at 120 r / min, and then extruding, casting into a film, cooling and setting at a casting roller temperature of 50°C, cooling at a cooling roller temperature of 20°C, and winding with a tension of 5 N to obtain the modified film material with a thickness deviation of ≤±5% and a tensile strength of ≥80 MPa.

[0036] Example Two: The modified film material comprises the following raw materials by weight parts: 75 parts of polyethylene terephthalate resin, 12.5 parts of reinforcing filler, 6.5 parts of functional filler, 3.5 parts of plasticizer, and 2.5 parts of antioxidant.

[0037] The reinforcing filler is composed of modified nano-montmorillonite and silane-treated calcium carbonate.

[0038] The functional filler is prepared by mixing hydroxylated graphene and nano-silver particles.

[0039] The modifier for the modified nano-montmorillonite is cetyltrimethylammonium bromide, and the amount of the modifier is 15% of the mass of the nano-montmorillonite. The modification method is as follows: crushing the raw material montmorillonite through a sieve, washing with deionized water to remove impurities, vacuum drying at 90°C for 5 h, dispersing the dried montmorillonite in deionized water with a solid-liquid ratio of 1:15 to form a suspension, adding the modifier, stirring at 80°C for 3 h, centrifuging the product after the reaction, washing with deionized water until no bromide ions are present, vacuum drying at 90°C for 10 h, and grinding the dried product to obtain the modified nano-montmorillonite.

[0040] The silane coupling agent in the silane-treated calcium carbonate is KH550, and the amount is 2% of the mass of the calcium carbonate. The treatment method is as follows: the calcium carbonate is crushed to a nanoscale, dried at 110°C for 3h to remove surface moisture, KH550 is dissolved in anhydrous ethanol, the volume ratio of silane to ethanol is 1:7.5, the PH is adjusted to 4, and the silane is hydrolyzed by stirring for 22min to obtain an activated silane solution. The treated calcium carbonate is added to a high-speed mixer with a rotation speed of 750r / min, and the activated silane solution is sprayed. The silane coupling agent is chemically bonded to the surface of the calcium carbonate by stirring and reacting at 70°C for 45min. Finally, the silane-treated calcium carbonate is vacuum dried at 90°C for 3h.

[0041] The preparation method of the reinforcing filler is as follows: modified nanometer montmorillonite and silane-treated calcium carbonate are weighed according to a mass ratio of 4:1.5, and then put into a horizontal stirring ball mill with zirconium oxide balls as the ball milling medium. The mass ratio of balls to material is 5:1, the rotation speed of the mill is controlled at 200r / min, and the grinding treatment is performed for 2.2h. After screening and removing the medium, the uniformly dispersed reinforcing filler is obtained.

[0042] The preparation method of the hydroxylated graphene is as follows: graphite powder, concentrated sulfuric acid and sodium nitrate are mixed according to a mass ratio of 12.5:225:3.5, and potassium permanganate is slowly added at 2°C. The mass ratio of potassium permanganate to graphite powder is 4:1. The mixture is stirred for 3h, then heated to 35°C for 1.5h, deionized water is added and heated to 95°C, and the mixture is kept at 95°C for 45min. After the reaction is completed, hydrogen peroxide solution is added to reduce the remaining oxidizing agent. After centrifugal separation, the mixture is washed with dilute hydrochloric acid and deionized water alternately until it is neutral. After freeze-drying and ultrasonic peeling, the hydroxylated graphene is obtained, with a sheet thickness of 1.4nm and a carbon atom ratio of 10:1.

[0043] The preparation method of the nano-silver particles is as follows: silver nitrate is dissolved in deionized water to prepare a 0.03mol / L solution, and 1.2% by mass of polyvinylpyrrolidone is added as a dispersant. Under stirring, 0.12mol / L sodium borohydride reducing agent is added dropwise. The mass ratio of silver nitrate to sodium borohydride is 1:3, the reaction temperature is 25°C, and the reaction time is 45min. After the reaction, the nano-silver particles are obtained by centrifugal separation, deionized water washing and vacuum drying. The particle size is 35nm, and the dispersion degree is ≥90%.

[0044] The preparation method of the functional filler is as follows: hydroxylated graphene and nano-silver particles are weighed according to a mass ratio of 4:1.5, and then added to deionized water to prepare a suspension with a solid content of 7.5%. The suspension is dispersed for 45min under ultrasonic frequency of 30kHz and power of 400W. Then, 2% of the mass of the suspension of silane coupling agent KH570 is added, and the mixture is stirred and reacted at 60°C for 1.5h. After centrifugal separation and vacuum drying at 70°C for 5h, the functional filler is obtained, with an agglomerated particle size of ≤100nm.

[0045] The plasticizer is dioctyl adipate, and the antioxidant is antioxidant 168.

[0046] The polyethylene terephthalate resin has an intrinsic viscosity of 0.75 dL / g, a carboxyl end group content of ≤20 mmol / kg, and an ash content of ≤0.1%.

[0047] The preparation method of the modified film material comprises the following steps: placing the polyethylene terephthalate resin in a vacuum drying oven at 130°C and drying for 4 hours to remove water; weighing the dried polyethylene terephthalate resin, reinforcing filler, functional filler, plasticizer, and antioxidant according to the weight parts, and feeding them into a high-speed mixer to mix at 90°C and a rotation speed of 400 r / min for 22 minutes to obtain a premix; feeding the premix into a twin-screw extruder, setting the extrusion temperature, feeding the material at 250°C, melting the material at 285°C, homogenizing the material at 275°C, and rotating the screw at 170 r / min, and then extruding and casting the material into a film, cooling and shaping the film at a casting roller temperature of 60°C, cooling the film at a cooling roller temperature of 25°C, and winding the film at a tension of 7.5 N to obtain the modified film material, which has a thickness deviation of ≤±5% and a tensile strength of ≥80 MPa.

[0048] Example Three: comprising the following raw materials by weight parts: 90 parts of polyethylene terephthalate resin, 20 parts of reinforcing filler, 10 parts of functional filler, 5 parts of plasticizer, and 4 parts of antioxidant;

[0049] The reinforcing filler is composed of modified nanometer montmorillonite and silane-treated calcium carbonate.

[0050] The functional filler is obtained by mixing hydroxylated graphene and nanosilver particles.

[0051] The modifier of the modified nanometer montmorillonite is cetyltrimethylammonium bromide, and the amount of the modifier is 20% of the mass of the nanometer montmorillonite. The modification method comprises the following steps: crushing the raw material montmorillonite and sieving, washing the montmorillonite with deionized water to remove impurities, drying the montmorillonite at 100°C under vacuum for 6 hours, dispersing the dried montmorillonite in deionized water at a solid-liquid ratio of 1:20 to form a suspension, adding the modifier, stirring at 90°C for 4 hours, centrifuging the product after the reaction, washing the product with deionized water until no bromide ions are present, drying the product at 100°C under vacuum for 12 hours, and grinding the dried product to obtain the modified nanometer montmorillonite.

[0052] The silane coupling agent in the silane treated calcium carbonate is KH550, and the amount is 1-3% of the mass of the calcium carbonate. The treatment method is as follows: the calcium carbonate is crushed to nanoscale, dried at 120℃ for 4h to remove the surface moisture, KH550 is dissolved in anhydrous ethanol, the volume ratio of silane to ethanol is 1:10, the PH is adjusted to 5, and the stirring hydrolysis is performed for 30min to obtain an activated silane solution. The treated calcium carbonate is added into a high-speed mixer with a rotation speed of 1000r / min, the activated silane solution is sprayed, and the stirring reaction is performed at 80℃ for 60min to make the silane coupling agent combined on the surface of the calcium carbonate by chemical bonds. Finally, the vacuum drying is performed at 100℃ for 4h to obtain the silane treated calcium carbonate.

[0053] The preparation method of the reinforcing filler is as follows: the modified nanometer montmorillonite and the silane treated calcium carbonate are weighed according to the mass ratio of 5:2, and then are put into a horizontal stirring ball mill, the zirconium oxide ball is used as the ball milling medium, the ball-to-material mass ratio is 6:1, the mill rotation speed is controlled at 250r / min, and the grinding treatment is performed for 3h. After the screening and the removal of the medium, the uniformly dispersed reinforcing filler is obtained.

[0054] The preparation method of the hydroxylated graphene is as follows: the graphite powder, concentrated sulfuric acid and sodium nitrate are mixed according to the mass ratio of 15:250:5, the potassium permanganate is slowly added at 5℃, the mass ratio of the potassium permanganate to the graphite powder is 5:1, the stirring reaction is performed for 4h, then the temperature is increased to 40℃ for 2h, deionized water is added and the temperature is increased to 100℃ for 60min of heat preservation reaction. After the reaction is completed, the hydrogen peroxide solution is added to reduce the residual oxidant, and after the centrifugal separation, the alternating washing with dilute hydrochloric acid and deionized water is performed until neutral. After the freeze drying and the ultrasonic peeling, the hydroxylated graphene is obtained, the sheet thickness is 2nm, and the carbon atom ratio is 12:1.

[0055] The preparation method of the nano silver particles is as follows: the silver nitrate is dissolved in deionized water to configure a 0.05mol / L solution, the polyvinylpyrrolidone with a mass fraction of 2% is added as a dispersant, the 0.2mol / L sodium borohydride reducing agent is added dropwise under stirring, the mass ratio of the silver nitrate to the sodium borohydride is 1:4, the reaction temperature is 30℃, the reaction time is 60min, and after the reaction, the centrifugal separation, deionized water washing and vacuum drying are performed to obtain the nano silver particles, the particle size is 50nm, and the dispersity is ≥90%.

[0056] The preparation method of the functional filler is as follows: the hydroxylated graphene and the nano silver particles are weighed according to the mass ratio of 5:2, deionized water is added to configure a suspension with a solid content of 10%, the ultrasonic frequency is 40kHz, the power is 500W, and the dispersion is performed for 60min. Then, the silane coupling agent KH570 with a mass of 3% of the suspension is added, the stirring reaction is performed at 70℃ for 2h, the centrifugal separation, 80℃ vacuum drying for 6h are performed, and the functional filler is obtained, the agglomerated particle size is ≤100nm.

[0057] The plasticizer is epoxy soybean oil, and the antioxidant is antioxidant 1076.

[0058] The polyethylene terephthalate resin has an intrinsic viscosity of 0.85 dL / g, a carboxyl end group content of ≤20 mmol / kg, and an ash content of ≤0.1%.

[0059] The preparation method of the modified film material comprises the following steps: placing the polyethylene terephthalate resin in a vacuum drying oven at 140°C and drying for 5 hours to remove moisture; weighing the dried polyethylene terephthalate resin, the reinforcing filler, the functional filler, the plasticizer, and the antioxidant according to the weight parts, and feeding them into a high-speed mixer to mix at 100°C and a rotation speed of 500 r / min for 30 minutes to obtain a premix; feeding the premix into a double-screw extruder, setting the extrusion temperature, feeding the material at 260°C, melting the material at 295°C, homogenizing the material at 285°C, and rotating the screw at 220 r / min, and then extruding and casting the material into a film, cooling and shaping the film at a casting roller temperature of 70°C, cooling the film at a cooling roller temperature of 30°C, winding the film, and setting the tension to 10 N to obtain the modified film material, wherein the thickness deviation of the modified film material is ≤±5%, and the tensile strength of the modified film material is ≥80 MPa.

[0060] Comparative Example 1, the difference between the comparative example and the embodiment is that no reinforcing filler is added in the comparative example.

[0061] Comparative Example 2, the difference between the comparative example and the embodiment is that no functional filler is added in the comparative example.

[0062] Comparative Example 3, the difference between the comparative example and the embodiment is that the nano-montmorillonite in the reinforcing filler is not modified, and the calcium carbonate is not treated with silane.

[0063] Comparative Example 4, the difference between the comparative example and the embodiment is that the particle dispersion degree of the nano-silver is low.

[0064] Performance test: the prepared products of Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 are subjected to performance testing.

[0065] Tensile strength test: a film sample meeting the standard requirements is clamped on a tensile testing machine, an axial tensile force is applied to the sample at a specified tensile rate until the sample is broken, the maximum tensile force value recorded by the tensile testing machine is combined with the original cross-sectional area of the sample to calculate the tensile strength, and the test is based on GB / T1040.3-2006;

[0066] Elongation at break test: first cut a sample of a specified size from the prepared modified film material, install the sample on a tensile testing machine, mark the initial gauge length on the sample, start the tensile testing machine, apply an axial tensile force to the sample at a standard specified tensile rate, as the tensile force increases, the sample is gradually stretched and lengthened, when the sample breaks, immediately stop the stretching, obtain the gauge length at the time of sample breakage, calculate the elongation at break, test basis: GB / T1040.3-2006;

[0067] Antibacterial rate test: select a standard test strain, prepare a bacterial suspension of a certain concentration and inoculate it on the surface of the modified film material, after incubation under specified conditions for a period of time, the viable bacterial count on the test group (antibacterial film) and the control group (blank film without antibacterial treatment) is determined by plate counting method, and the antibacterial rate is calculated, test basis: GB / T31402-2015;

[0068] Thickness deviation test: use a contact thickness gauge to measure the thickness of the modified film at different positions (at least 5 test points are selected according to the uniform distribution principle), record the measured thickness of each point, calculate the difference between the measured thickness and the target thickness, then multiply the difference by 100% of the target thickness to obtain the thickness deviation of each point, finally take the maximum value of the deviation of all test points as the thickness deviation of the film, test basis: GB / T6672-2001.

[0069] The test data obtained are recorded in the following table:

[0070]

[0071] By comparing and analyzing the relevant data in the table, it can be seen that the modified film material prepared by the modified film material and the preparation method of the film material not only has good strength performance, but also has good elongation at break and antibacterial rate, and the thickness deviation is low, the overall performance is more consistent, and the yield is higher. Therefore, the modified film material and the preparation method of the film material provided by the present application have a broader market prospect and are more suitable for promotion.

[0072] In the description of the present specification, the description of the terms "one embodiment", "example", "specific example" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are contained in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0073] The preferred embodiments of the application disclosed above are only to facilitate the elucidation of the application. The preferred embodiments do not describe all the details of the application and limit the application to the specific embodiments described. Obviously, many modifications and variations can be made in light of the teachings above. The description is chosen and described in order to best explain the principles of the application and its practical application to thereby enable others skilled in the art to best utilize the application and get the best results from the application. The application is only limited by the claims and their full scope and equivalents.

Claims

1. Modified film material, characterized in that: The invention comprises the following raw materials in parts by weight: 60-90 parts of polyethylene terephthalate resin, 5-20 parts of reinforcing filler, 3-10 parts of functional filler, 2-5 parts of plasticizer, and 1-4 parts of antioxidant; The reinforcing filler consists of modified nano-montmorillonite and silane-treated calcium carbonate; The functional filler is prepared by mixing hydroxylated graphene and nano silver particles.

2. The modified film material according to claim 1, characterized in that: The modified nano-montmorillonite comprises a modifier of hexadecyltrimethylammonium bromide, and the amount of the modifier is 10-20% of the mass of the nano-montmorillonite. The modification method comprises the following steps: crushing and sieving the raw montmorillonite, washing with deionized water to remove impurities, vacuum drying at 80-100° C. for 4-6 hours, dispersing the dried montmorillonite in deionized water with a solid-liquid ratio of 1:(10-20), stirring to form a suspension, adding the modifier, stirring at 70-90° C. for 2-4 hours, centrifuging and separating the product after the reaction, washing with deionized water until there is no bromide ion, vacuum drying at 80-100° C. for 8-12 hours, and grinding after drying to obtain the modified nano-montmorillonite.

3. The modified film material according to claim 1, characterized in that The silane coupling agent in the silane-treated calcium carbonate is KH550, and the amount used is 1-3% of the mass of the calcium carbonate. The treatment method comprises the following steps: crushing the calcium carbonate to nanometer level, drying at 100-120°C for 2-4 hours, removing surface moisture, dissolving KH550 in anhydrous ethanol with a volume ratio of silane to ethanol of 1:(5-10), adjusting the pH to 3-5, stirring and hydrolyzing for 15-30 minutes to obtain an activated silane solution, adding the treated calcium carbonate into a high-speed mixer with a rotation speed of 500-1000 r / min, spraying the activated silane solution, stirring and reacting at 60-80°C for 30-60 minutes, so that the silane coupling agent is chemically bonded to the surface of the calcium carbonate, and finally vacuum drying at 80-100°C for 2-4 hours to obtain the silane-treated calcium carbonate.

4. The modified film material according to claim 1, characterized in that: The preparation method of the reinforcing filler comprises the following steps: weighing modified nano-montmorillonite and silane-treated calcium carbonate in a mass ratio of (3-5): (1-2), placing the two into a horizontal stirred ball mill, using zirconium oxide balls as ball milling media, a ball-to-material mass ratio of (4-6):1, controlling the mill speed at 150-250 r / min, grinding for 1.5-3 hours, and obtaining a uniformly dispersed reinforcing filler after screening and removing the media.

5. The modified film material according to claim 1, characterized in that: The preparation method of the hydroxylated graphene comprises the following steps: mixing graphite powder, concentrated sulfuric acid and sodium nitrate in a mass ratio of (10-15):(200-250):(2-5), slowly adding potassium permanganate at 0-5°C, wherein the mass ratio of potassium permanganate to graphite powder is (3-5:1), stirring and reacting for 2-4 hours, then heating to 30-40°C and reacting for 1-2 hours, then adding deionized water and heating to 90-100°C, and keeping the temperature for reaction for 30-60 minutes. After the reaction, hydrogen peroxide solution is added to reduce the remaining oxidant, centrifugally separating, washing alternately with dilute hydrochloric acid and deionized water until neutral, freeze-drying, and ultrasonically exfoliating to obtain the hydroxylated graphene, wherein the hydroxylated graphene has a sheet thickness of 0.8-2 nm and a carbon atomic ratio of (8-12):

1.

6. The modified film material according to claim 1, characterized in that: The preparation method of the nano silver particles comprises the following steps: dissolving silver nitrate in deionized water to prepare a 0.01-0.05 mol / L solution, adding 0.5-2% by mass of polyvinyl pyrrolidone as a dispersant, and dropwise adding 0.05-0.2 mol / L of sodium borohydride as a reducing agent under stirring, wherein the molar ratio of silver nitrate to sodium borohydride is 1:(2-4), the reaction temperature is 20-30°C, the reaction time is 30-60 minutes, and after the reaction, the solution is centrifuged, washed with deionized water, and vacuum dried to obtain nano silver particles with a particle size of 20-50 nm and a dispersion of ≥90%.

7. The modified film material according to claim 1, characterized in that: The functional filler is prepared by weighing hydroxylated graphene and nanosilver particles in a mass ratio of (3-5): (1-2), adding deionized water to form a suspension with a solid content of 5-10%, dispersing the suspension for 30-60 minutes at an ultrasonic frequency of 20-40 kHz and a power of 300-500 W, then adding 1-3% of the mass of the suspension as a silane coupling agent KH570, stirring and reacting at 50-70° C. for 1-2 hours, centrifuging, and vacuum drying at 60-80° C. for 4-6 hours to obtain the functional filler, wherein the agglomerated particle size is ≤100 nm.

8. The modified film material according to claim 1, characterized in that: The plasticizer is one of dimethyl phthalate, dioctyl adipate or epoxidized soybean oil; the antioxidant is one of antioxidant 1010, antioxidant 168 or antioxidant 1076.

9. The modified film material according to claim 1, characterized in that: The polyethylene terephthalate resin has an intrinsic viscosity of 0.65-0.85 dL / g, a terminal carboxyl content of ≤20 mmol / kg, and an ash content of ≤0.1%.

10. A method for preparing a modified film material, comprising the modified film material according to any one of claims 1 to 9, wherein: The following steps are involved: The polyethylene terephthalate resin is placed in a vacuum drying oven at 120-140° C. and dried for 3-5 hours to remove moisture; the dried polyethylene terephthalate resin, reinforcing filler, functional filler, plasticizer and antioxidant are weighed by weight, and the mixture is put into a high-speed mixer and mixed for 15-30 minutes at 80-100° C. and a rotation speed of 300-500 r / min to obtain a premix; the premix is ​​added to a twin-screw extruder, and the extrusion temperature is set to 240-260° C. in the feeding section, 275-295° C. in the melting section, and 265-285° C. in the homogenizing section, and the screw speed is set to 120-220 r / min. The premix is ​​extruded and cast into a film, the casting roll temperature is 50-70° C., cooling and shaping is performed, the cooling roll temperature is 20-30° C., winding is performed, and the tension is 5-10N to obtain a modified film material with a thickness deviation of ≤±5% and a tensile strength of ≥80 MPa.

Images