A transparent flame-retardant polypropylene ultra-thin sheet

Abstract

The invention is applicable to the technical field of plastic processing, and provides a transparent flame-retardant polypropylene ultra-thin sheet and a preparation method thereof. The transparent flame-retardant polypropylene ultra-thin sheet comprises the following raw materials: polypropylene, an organic phosphorus flame retardant, a permeability enhancer, a nano inorganic additive, modified polyethylene glycol, an antioxidant, modified nano mullite, and a lubricant. The transparent flame-retardant polypropylene ultra-thin sheet has high transparency and high flame retardant performance, and its transparency can reach more than 90%. The flame retardant grade of UL94V-0 is achieved within a thickness range of 0.2-1.0 mm, which is superior to ordinary polypropylene and a polypropylene ultra-thin sheet with flame retardant added. The preparation method is environmentally friendly, does not need to use a halogen flame retardant, and avoids environmental pollution and human harm caused by the halogen flame retardant. At the same time, the used organic phosphorus flame retardant and the nano inorganic additive are both low-toxic or non-toxic substances, which are harmless to the environment and the human body.

Description

Technical Field

[0001] The invention belongs to the technical field of plastic processing, and in particular relates to a transparent flame-retardant polypropylene ultra-thin plate. Background Art

[0002] Polypropylene (PP) is a non-toxic, odorless, tasteless, translucent milky white, highly crystalline, non-polar polymer made from propylene, a product of petroleum cracking. PP has a wide range of market applications, among which flame-retardant PP sheet is an important field.

[0003] Existing flame-retardant PP sheets generally use halogen flame retardants, which produce a large amount of smoke, toxic and corrosive gases, release carcinogens, cause environmental pollution, and harm human health when they exert their flame-retardant properties. Summary of the invention

[0004] The present invention provides a transparent flame-retardant PP ultra-thin plate, aiming to solve the above-mentioned problem.

[0005] The present invention is achieved in this way: a transparent flame-retardant PP ultra-thin plate comprises the following raw materials in parts by weight: 85-100 parts of PP, 0.5-5 parts of organic phosphorus flame retardant, 0.2-0.8 parts of permeability enhancer, 0.1-1 parts of nano inorganic additive, 0.5-4.5 parts of modified polyethylene glycol, 0.1-0.5 parts of antioxidant, 1-5 parts of modified nano mullite and 0.2-1 parts of lubricant.

[0006] Preferably, the following raw materials are included in parts by weight: PP85-95 parts, organophosphorus flame retardant 1.5-4 parts, permeability enhancer 0.4-0.6 parts, nano inorganic additive 0.3-0.8 parts, modified polyethylene glycol 3-4 parts, antioxidant 0.2-0.3 parts, modified nano mullite 2-4 parts, lubricant 0.3-0.6 parts.

[0007] Preferably, the following raw materials are included in parts by weight: 90 parts of PP, 2.75 parts of organic phosphorus flame retardant, 0.5 parts of permeability enhancer, 0.55 parts of nano inorganic additive, 4 parts of modified polyethylene glycol, 0.2 parts of antioxidant, 3 parts of modified nano mullite, and 0.3 parts of lubricant.

[0008] Preferably, the PP is homopolymer PP or copolymer PP, and its melt index (MFI) is 1-5g / 10min, the organophosphorus flame retardant includes at least one of triphenyl phosphate and triphenyl phosphate derivatives, and the permeability enhancer includes at least one of sorbitol, polyvinyl cyclobutane, and sodium benzoate.

[0009] Preferably, the nano inorganic additive comprises one or more combinations of nano calcium carbonate, nano talc, nano barium sulfate and nano alumina, and the average particle size of the nano inorganic additive is 10-100 nm.

[0010] Preferably, the preparation method of the modified polyethylene glycol is as follows: take polyethylene glycol, p-aminophenyltrimethoxysilane, N,N-dimethylformamide, and 3-amino-1,2-propylene glycol in a mass ratio of 15-25:2-4:0.2-0.4:0.3-0.5, first mix the polyethylene glycol and p-aminophenyltrimethoxysilane, heat to 70-90°C, stir for 30-50 minutes, then add N,N-dimethylformamide and 3-amino-1,2-propylene glycol, and continue stirring for 20-40 minutes. , extracted with dichloromethane, precipitated with anhydrous ether, and vacuum dried to obtain modified polyethylene glycol; p-aminophenyltrimethoxysilane was used to prepare a two-dimensional layered structure, and polyethylene glycol was inserted in situ to increase the spacing between the layered structures and improve the dispersibility; then N,N-dimethylformamide and 3-amino-1,2-propylene glycol were added to graft amino groups on the ends of polyethylene glycol to enhance the reactivity of polyethylene glycol, and it was compounded with other components to react with each other to form a macromolecular network structure, so that the ultra-thin sheet has a stable internal structure and improved mechanical properties.

[0011] Preferably, the preparation method of the modified nano-mullite is as follows: the nano-mullite is placed in 10-15 times the weight concentration of 0.6 mol / L hydrochloric acid, heated to 40-50°C, stirred and soaked for 1-2 hours, then filtered, washed with distilled water 2-4 times, and then placed in a vacuum drying oven at 80°C for 30-50 minutes to obtain product A, 0.05-0.1 times the weight of hexadecyltrimethylammonium bromide and 6-10 times the weight of deionized water are added to product A, and stirred at 70-90°C. Stir for 30-40 minutes, filter and dry to obtain modified nano-mullite; then add hydrochloric acid to clean and modify the surface of the nano-mullite, destroy the structure to form porous characteristics, dissolve impurities in the particle channels, and clear the channels; add hexadecyltrimethylammonium bromide to cause a cation exchange reaction, and organic groups cover the surface of the mullite or insert between its layers, so that its surface energy changes, increases the interlayer spacing, improves the adsorption, dispersibility and binding ability with other components, thereby improving the mechanical properties of the ultra-thin plate.

[0012] Preferably, the lubricant includes at least one of bisphenol A and bisphenol A derivatives, and the lubricant includes at least one of zinc stearate and zinc stearate derivatives.

[0013] The present invention also provides a method for preparing the transparent flame-retardant PP ultra-thin sheet, comprising the following steps:

[0014] 1) Weighing raw materials according to the proportions, and mixing the raw materials to obtain a mixture;

[0015] 2) Melting and extruding the mixture through a twin-screw extruder, cooling and pelletizing, wherein the temperature of the twin-screw extruder is 170-210° C., the rotation speed is 300-500 rpm, and the pressure is 0.5-10 MPa;

[0016] 3) Melting the particles and extruding through a die to obtain a transparent flame-retardant PP sheet, wherein the temperature of the die is 200-230° C., the pressure is 15-25 MPa, and the extrusion speed is 0.5-1 m / min;

[0017] 4) hot pressing the transparent flame retardant PP sheet through a hot press to obtain a transparent flame retardant PP plate, wherein the temperature of the hot press is 180-200° C., the pressure is 5-10 MPa, and the time is 1-5 min;

[0018] 5) The transparent flame-retardant PP sheet is uniaxially stretched to obtain a transparent flame-retardant PP ultra-thin sheet.

[0019] Preferably, the uniaxial stretching step is as follows:

[0020] Preheating: The unstretched PP sheet passes through a preheating device to raise its temperature to a temperature close to the glass transition temperature;

[0021] Stretching: The preheated PP sheet is passed through a stretching device and stretched in one direction to form an oriented structure of its molecular chains, thus forming a uniaxially stretched PP sheet;

[0022] Heat setting: The uniaxially stretched PP sheet is passed through a heat setting device to raise its temperature to near the melting point, and then rapidly cooled to fix its molecular chains in the stretched state;

[0023] Cutting: The heat-set PP sheet is passed through a cutting device and cut into the required size and shape, wherein the cutting speed of the cutting device is 0.1-0.5m / min.

[0024] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0025] The transparent flame-retardant PP ultra-thin sheet provided by the present invention has high transparency and high flame-retardant performance, and its transparency can reach more than 90%. It can reach UL94 V-0 flame-retardant grade in the thickness range of 0.2-1.0 mm, which is superior to ordinary PP and PP ultra-thin sheet with added flame retardant.

[0026] The preparation method of the transparent flame-retardant PP ultra-thin plate provided by the present invention is environmentally friendly and does not require the use of halogen flame retardants, thereby avoiding the environmental pollution and human harm caused by halogen flame retardants. At the same time, the organic phosphorus flame retardants and nano inorganic additives used are low-toxic or non-toxic substances and are harmless to the environment and human body.

[0027] The transparent flame-retardant PP ultra-thin sheet provided by the present invention is compounded with other components by adding modified polyethylene glycol, and reacts with each other to form a macromolecular network structure, so that the ultra-thin sheet has a stable internal structure and improved mechanical properties. By adding modified nano-mullite, it has porous characteristics, good adsorption, dispersibility and bonding ability with other components, and improves the mechanical properties of the ultra-thin sheet. The modified polyethylene glycol and the modified nano-mullite have a synergistic effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a flow chart of a method for preparing a transparent flame-retardant PP ultra-thin sheet provided by the present invention;

[0029] Figure 2 The present invention provides a uniaxial stretching flow chart for a method for preparing a transparent flame-retardant PP ultra-thin sheet. DETAILED DESCRIPTION

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of this application; the terms used in the specification of the application herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0031] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0032] Example 1

[0033] The embodiment of the present invention provides a transparent flame-retardant PP ultra-thin sheet, such as Figure 1 As shown, the preparation method comprises the following steps:

[0034] 1) Weigh the following raw materials in parts by weight according to the ratio: 90 parts of PP, 0.5 parts of organophosphorus flame retardant, 0.2 parts of permeability enhancer, 0.1 parts of nano inorganic additive, 0.5 parts of modified polyethylene glycol, 0.2 parts of antioxidant, 1 part of modified nano mullite, and 0.3 parts of lubricant, and mix the raw materials to obtain a mixture;

[0035] 2) melt-extrude the mixture through a twin-screw extruder, cool and pelletize, wherein the temperature of the twin-screw extruder is 180° C., the speed is 300 rpm, and the pressure is 2.0 MPa;

[0036] 3) extruding the melted particles through a die to obtain a transparent flame-retardant PP sheet, wherein the temperature of the die is 200° C., the pressure is 15 MPa, and the extrusion speed is 0.5 m / min;

[0037] 4) hot pressing the transparent flame-retardant PP sheet through a hot press to obtain a transparent flame-retardant PP plate, wherein the temperature of the hot press is 180° C., the pressure is 5 MPa, and the time is 1 min;

[0038] 5) The transparent flame-retardant PP sheet is uniaxially stretched to obtain a transparent flame-retardant PP ultra-thin sheet.

[0039] Among them, Figure 2 As shown, the steps of uniaxial stretching are as follows:

[0040] Preheating: The unstretched PP sheet passes through a preheating device to raise its temperature to a temperature close to the glass transition temperature;

[0041] Stretching: The preheated PP sheet is passed through a stretching device and stretched in one direction to orient its molecular chains to form a uniaxially stretched PP sheet;

[0042] Heat setting: The uniaxially stretched PP sheet is passed through a heat setting device to raise its temperature to near the melting point, and then rapidly cooled to fix its molecular chains in the stretched state;

[0043] Cutting: The heat-set PP sheet is passed through a cutting device and cut into the required size and shape.

[0044] In this embodiment, the PP is homopolymer PP, and its MFI is 3g / 10min, the organophosphorus flame retardant is triphenyl phosphate, the permeability enhancer is sorbitol, the nano inorganic additive is nano alumina, and its average particle size is 50nm, the lubricant is bisphenol A type, and the lubricant is zinc stearate.

[0045] Specifically, the preparation method of the modified polyethylene glycol is as follows: take polyethylene glycol, p-aminophenyltrimethoxysilane, N,N-dimethylformamide, and 3-amino-1,2-propylene glycol in a mass ratio of 15:2:0.2:0.3, first mix the polyethylene glycol and p-aminophenyltrimethoxysilane, heat to 70°C, stir for 30 minutes, then add N,N-dimethylformamide and 3-amino-1,2-propylene glycol, continue stirring for 20 minutes, extract with dichloromethane, precipitate with anhydrous ether, and vacuum dry to obtain the modified polyethylene glycol.

[0046] In a specific implementation, the preparation method of the modified nano-mullite is as follows: the nano-mullite is placed in 10 times the weight concentration of 0.6 mol / L hydrochloric acid, heated to 40°C, stirred and soaked for 1 hour, then filtered, washed with distilled water twice, and then placed in a vacuum drying oven at 80°C for 30 minutes to obtain product A. 0.05 times the weight of hexadecyltrimethylammonium bromide and 6 times the weight of deionized water are added to product A, stirred at 70°C for 30 minutes, and filtered and dried in sequence to obtain modified nano-mullite.

[0047] Example 2

[0048] The embodiment of the present invention provides a transparent flame-retardant PP ultra-thin sheet, such as Figure 1 As shown, the preparation method thereof comprises the following steps:

[0049] 2) The mixture is melt-extruded through a twin-screw extruder, cooled and pelletized, and the temperature of the twin-screw extruder is 180° C., the speed is 300 rpm, and the pressure is 2.0 MPa;

[0050] 3) extruding the melted particles through a die to obtain a transparent flame-retardant PP sheet, wherein the temperature of the die is 200° C., the pressure is 15 MPa, and the extrusion speed is 0.5 m / min;

[0051] 4) hot pressing the transparent flame-retardant PP sheet through a hot press to obtain a transparent flame-retardant PP plate, wherein the temperature of the hot press is 180° C., the pressure is 5 MPa, and the time is 1 min;

[0052] 5) The transparent flame-retardant PP sheet is uniaxially stretched to obtain a transparent flame-retardant PP ultra-thin sheet.

[0053] Among them, Figure 2 As shown, the steps of uniaxial stretching are as follows:

[0054] Preheating: The unstretched PP sheet passes through a preheating device to raise its temperature to a temperature close to the glass transition temperature;

[0055] Stretching: The preheated PP sheet is passed through a stretching device and stretched in one direction to orient its molecular chains to form a uniaxially stretched PP sheet;

[0056] Heat setting: The uniaxially stretched PP sheet is passed through a heat setting device to raise its temperature to near the melting point, and then rapidly cooled to fix its molecular chains in the stretched state;

[0057] Cutting: The heat-set PP sheet is passed through a cutting device and cut into the required size and shape.

[0058] In this embodiment, the PP is homopolymer PP, and its MFI is 3g / 10min, the organophosphorus flame retardant is triphenyl phosphate, the permeability enhancer is sorbitol, the nano inorganic additive is nano alumina, and its average particle size is 50nm, the lubricant is bisphenol A type, and the lubricant is zinc stearate.

[0059] Specifically, the preparation method of the modified polyethylene glycol is as follows: polyethylene glycol, p-aminophenyltrimethoxysilane, N,N-dimethylformamide, and 3-amino-1,2-propylene glycol are taken in a mass ratio of 15:2:0.2:0.3. Polyethylene glycol and p-aminophenyltrimethoxysilane are first mixed, heated to 70°C, stirred for 30 minutes, and then N,N-dimethylformamide and 3-amino-1,2-propylene glycol are added, and stirring is continued for 20 minutes, extracted with dichloromethane, precipitated with anhydrous ether, and vacuum dried to obtain the modified polyethylene glycol.

[0060] In a specific implementation, the preparation method of the modified nano-mullite is as follows: the nano-mullite is placed in 10 times the weight concentration of 0.6 mol / L hydrochloric acid, heated to 40°C, stirred and soaked for 1 hour, then filtered, washed with distilled water twice, and then placed in a vacuum drying oven at 80°C for 30 minutes to obtain product A. 0.05 times the weight of hexadecyltrimethylammonium bromide and 6 times the weight of deionized water are added to product A, stirred at 70°C for 30 minutes, and filtered and dried in sequence to obtain modified nano-mullite.

[0061] Example 3

[0062] The embodiment of the present invention provides a transparent flame-retardant PP ultra-thin sheet, such as Figure 1 As shown, the preparation method comprises the following steps:

[0063] 2) melt-extrude the mixture through a twin-screw extruder, cool and pelletize, wherein the temperature of the twin-screw extruder is 200° C., the speed is 400 rpm, and the pressure is 1.5 MPa;

[0064] 3) extruding the melted particles through a die to obtain a transparent flame-retardant PP sheet, wherein the die temperature is 215° C., the pressure is 20 MPa, and the extrusion speed is 0.75 m / min;

[0065] 4) hot pressing the transparent flame retardant PP sheet through a hot press to obtain a transparent flame retardant PP plate, wherein the temperature of the hot press is 190° C., the pressure is 7.5 MPa, and the time is 3 min;

[0066] 5) The transparent flame-retardant PP sheet is uniaxially stretched to obtain a transparent flame-retardant PP ultra-thin sheet.

[0067] Among them, Figure 2 As shown, the steps of uniaxial stretching are as follows:

[0068] Preheating: The unstretched PP sheet passes through a preheating device to raise its temperature to a temperature close to the glass transition temperature;

[0069] Stretching: The preheated PP sheet is passed through a stretching device and stretched in one direction to orient its molecular chains to form a uniaxially stretched PP sheet;

[0070] Heat setting: The uniaxially stretched PP sheet is passed through a heat setting device to raise its temperature to near the melting point, and then rapidly cooled to fix its molecular chains in the stretched state;

[0071] Cutting: The heat-set PP sheet is passed through a cutting device and cut into the required size and shape.

[0072] In this embodiment, the PP is homopolymer PP, and its MFI is 3g / 10min, the organophosphorus flame retardant is triphenyl phosphate, the permeability enhancer is sorbitol, the nano inorganic additive is nano alumina, and its average particle size is 50nm, the lubricant is bisphenol A type, and the lubricant is zinc stearate.

[0073] Specifically, the preparation method of the modified polyethylene glycol is as follows: take polyethylene glycol, p-aminophenyltrimethoxysilane, N,N-dimethylformamide, and 3-amino-1,2-propylene glycol in a mass ratio of 20:3:0.3:0.4, first mix polyethylene glycol and p-aminophenyltrimethoxysilane, heat to 80°C, and stir for 40 minutes. Then add N,N-dimethylformamide and 3-amino-1,2-propylene glycol, and continue stirring for 30 minutes. Extract with dichloromethane, precipitate with anhydrous ether, and vacuum dry to obtain modified polyethylene glycol.

[0074] In a specific implementation, the preparation method of the modified nano-mullite is as follows: the nano-mullite is placed in 13 times the weight of hydrochloric acid with a concentration of 0.6 mol / L, heated to 45°C, and stirred and soaked for 1.5 hours. Then filtered, washed with distilled water 3 times, and then placed in a vacuum drying oven at 80°C for 40 minutes to obtain product A. 0.07 times the weight of hexadecyltrimethylammonium bromide and 8 times the weight of deionized water are added to product A, stirred at 80°C for 35 minutes, and filtered and dried in turn to obtain modified nano-mullite.

[0075] Example 4

[0076] The embodiment of the present invention provides a transparent flame-retardant PP ultra-thin sheet, such as Figure 1 As shown, the preparation method comprises the following steps:

[0077] 2) melt-extrude the mixture through a twin-screw extruder, cool and pelletize, wherein the temperature of the twin-screw extruder is 210° C., the speed is 500 rpm, and the pressure is 1.0 MPa;

[0078] 3) The particles are melted and extruded through a die to obtain a transparent flame-retardant PP sheet, the die temperature is 230° C., the pressure is 25 MPa, and the extrusion speed is 1 m / min;

[0079] 4) The transparent flame-retardant PP sheet is hot-pressed in a hot press to obtain a transparent flame-retardant PP plate. The hot press temperature is 200°C, the pressure is 10 MPa, and the time is 5 minutes;

[0080] 5) The transparent flame-retardant PP sheet is uniaxially stretched to obtain a transparent flame-retardant PP ultra-thin sheet.

[0081] Among them, Figure 2 As shown, the steps of uniaxial stretching are as follows:

[0082] Preheating: The unstretched PP sheet passes through a preheating device to raise its temperature to a temperature close to the glass transition temperature;

[0083] Stretching: The preheated PP sheet is passed through a stretching device and stretched in one direction to orient its molecular chains to form a uniaxially stretched PP sheet;

[0084] Heat setting: The uniaxially stretched PP sheet is passed through a heat setting device to raise its temperature to near the melting point, and then rapidly cooled to fix its molecular chains in the stretched state;

[0085] Cutting: The heat-set PP sheet is passed through a cutting device and cut into the required size and shape.

[0086] In this embodiment, the PP is homopolymer PP, and its MFI is 3g / 10min; the organophosphorus flame retardant is triphenyl phosphate, and the permeability enhancer is sorbitol; the nano inorganic additive is nano alumina, and its average particle size is 50nm; the lubricant is bisphenol A type, and the lubricant is zinc stearate.

[0087] Specifically, the preparation method of the modified polyethylene glycol is as follows: take polyethylene glycol, p-aminophenyltrimethoxysilane, N,N-dimethylformamide, and 3-amino-1,2-propylene glycol in a mass ratio of 25:4:0.4:0.5, first mix the polyethylene glycol and p-aminophenyltrimethoxysilane, heat to 90°C, stir for 50 minutes, then add N,N-dimethylformamide and 3-amino-1,2-propylene glycol, continue stirring for 40 minutes, extract with dichloromethane, precipitate with anhydrous ether, and vacuum dry to obtain the modified polyethylene glycol.

[0088] In a specific implementation, the preparation method of the modified nano-mullite is as follows: the nano-mullite is placed in 15 times the weight concentration of 0.6 mol / L hydrochloric acid, heated to 50°C, and stirred and soaked for 2 hours. Then filtered, washed with distilled water 4 times, and then placed in a vacuum drying oven at 80°C for 50 minutes to obtain product A. 0.1 times the weight of hexadecyltrimethylammonium bromide and 10 times the weight of deionized water are added to product A, stirred at 90°C for 40 minutes, and filtered and dried in sequence to obtain modified nano-mullite.

[0089] Example 5

[0090] The embodiment of the present invention provides a transparent flame-retardant PP ultra-thin sheet, such as Figure 1 As shown, the preparation method thereof comprises the following steps:

[0091] 2) melt-extrude the mixture through a twin-screw extruder, cool and pelletize, wherein the temperature of the twin-screw extruder is 210° C., the speed is 500 rpm, and the pressure is 1.0 MPa;

[0092] 3) extruding the melted particles through a die to obtain a transparent flame-retardant PP sheet, wherein the temperature of the die is 230° C., the pressure is 25 MPa, and the extrusion speed is 1 m / min;

[0093] 4) hot pressing the transparent flame-retardant PP sheet through a hot press to obtain a transparent flame-retardant PP plate, wherein the temperature of the hot press is 200° C., the pressure is 10 MPa, and the time is 5 min;

[0094] 5) The transparent flame-retardant PP sheet is uniaxially stretched to obtain a transparent flame-retardant PP ultra-thin sheet.

[0095] Among them, Figure 2 As shown, the steps of uniaxial stretching are as follows:

[0096] Preheating: The unstretched PP sheet passes through a preheating device to raise its temperature to a temperature close to the glass transition temperature;

[0097] Stretching: The preheated PP sheet is passed through a stretching device and stretched in one direction to orient its molecular chains to form a uniaxially stretched PP sheet;

[0098] Heat setting: The uniaxially stretched PP sheet is passed through a heat setting device to raise its temperature to near the melting point, and then rapidly cooled to fix its molecular chains in the stretched state;

[0099] Cutting: The heat-set PP sheet is passed through a cutting device and cut into the required size and shape.

[0100] In this embodiment, the PP is homopolymer PP, and its MFI is 3g / 10min, the organophosphorus flame retardant is triphenyl phosphate, the permeability enhancer is sorbitol, the nano inorganic additive is nano alumina, and its average particle size is 50nm, the lubricant is bisphenol A type, and the lubricant is zinc stearate.

[0101] Specifically, the preparation method of the modified polyethylene glycol is as follows: take polyethylene glycol, p-aminophenyltrimethoxysilane, N,N-dimethylformamide, and 3-amino-1,2-propylene glycol in a mass ratio of 25:4:0.4:0.5, first mix the polyethylene glycol and p-aminophenyltrimethoxysilane, heat to 90°C, stir for 50 minutes, then add N,N-dimethylformamide and 3-amino-1,2-propylene glycol, continue stirring for 40 minutes, extract with dichloromethane, precipitate with anhydrous ether, and vacuum dry to obtain the modified polyethylene glycol.

[0102] In a specific implementation, the preparation method of the modified nano-mullite is as follows: the nano-mullite is placed in 15 times the weight concentration of 0.6 mol / L hydrochloric acid, heated to 50°C, stirred and soaked for 2 hours, then filtered, washed with distilled water 4 times, and then placed in a vacuum drying oven at 80°C for 50 minutes to obtain product A. 0.1 times the weight of hexadecyltrimethylammonium bromide and 10 times the weight of deionized water are added to product A, stirred at 90°C for 40 minutes, and filtered and dried in sequence to obtain modified nano-mullite.

[0103] Comparative Example 1

[0104] Compared with Example 3, the modified polyethylene glycol is replaced by ordinary polyethylene glycol.

[0105] Comparative Example 2

[0106] Compared with Example 3, the modified nano-mullite is replaced by ordinary nano-mullite.

[0107] Comparative Example 3

[0108] Compared with Example 3, the modified polyethylene glycol is replaced by ordinary polyethylene glycol and the modified nano-mullite is replaced by ordinary nano-mullite.

[0109] Comparative Example 4

[0110] A commercially available transparent flame retardant PP sheet.

[0111] Performance Testing

[0112] The transparency test and the flame retardancy test were performed on the plates of Examples 1-5 and Comparative Example 4. The results are shown in Table 1 below:

[0113] Group transparency(%) Flame retardancy (UL94) Example 1 90 V-0(0.8mm) Example 2 92 V-0(0.8mm) Example 3 95 V-0(0.8mm) Example 4 93 V-0(0.8mm) Example 5 91 V-0(0.8mm) Comparative Example 4 83 V-2(0.8mm)

[0114] It can be seen from the above results that the transparent flame-retardant PP ultra-thin sheet prepared by the present invention has good transparency and flame retardancy.

[0115] The mechanical properties of the plates of Examples 1-5 and Comparative Examples 1-4 were tested. The notched impact strength was tested according to the requirements of IS0180-93, the tensile properties were tested according to the requirements of IS0527-93, and the flexural strength was tested according to the requirements of IS0178-93. The results are shown in Table 2 below:

[0116] Group <![CDATA[Notched impact strength (KJ / m 2 )]]> Tensile strength(MPa) Bending strength(MPa) Example 1 3.8 34.3 45.6 Example 2 4.5 32.7 41.9 Example 3 4.3 33.1 43.2 Example 4 4.1 33.9 44.9 Example 5 3.5 34.6 45.7 Comparative Example 1 3.1 36.1 45.4 Comparative Example 2 2.5 31.5 42.7 Comparative Example 3 2.8 30.3 42.5 Comparative Example 4 2.5 31.2 41.8

[0117] It can be seen from the above results that the transparent flame-retardant PP ultra-thin sheet prepared by the present invention has good mechanical properties. By adding modified polyethylene glycol and modified nano-mullite, the two have a synergistic effect and can further improve the mechanical properties of the transparent flame-retardant PP ultra-thin sheet.

[0118] It should be noted that, for the above embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the described order of actions, because according to the present invention, some steps may be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0119] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the scope of protection of the invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on these embodiments, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field can still combine, add, delete or make other adjustments to the features in the various embodiments of the present invention according to the circumstances without conflict, without making creative work, so as to obtain different other technical solutions that do not deviate from the concept of the present invention in essence, and these technical solutions also belong to the scope of protection of the present invention.

Claims

1. A transparent flame-retardant polypropylene ultra-thin sheet, characterized in that: The invention comprises the following raw materials in parts by weight: 85-100 parts of polypropylene, 0.5-5 parts of organic phosphorus flame retardant, 0.2-0.8 parts of permeability enhancer, 0.1-1 parts of nano inorganic additive, 0.5-4.5 parts of modified polyethylene glycol, 0.1-0.5 parts of antioxidant, 1-5 parts of modified nano mullite and 0.2-1 parts of lubricant; The preparation method of the modified polyethylene glycol is as follows: polyethylene glycol, p-aminophenyltrimethoxysilane, N, N-dimethylformamide, and 3-amino-1, 2-propylene glycol are taken in a mass ratio of 15-25:2-4:0.2-0.4:0.3-0.5, the polyethylene glycol and p-aminophenyltrimethoxysilane are first mixed, the temperature is raised to 70-90° C., and stirred for 30-50 min, then N, N-dimethylformamide and 3-amino-1, 2-propylene glycol are added, and stirring is continued for 20-40 min, extracted with dichloromethane, precipitated with anhydrous ether, and vacuum dried to obtain the modified polyethylene glycol; The preparation method of the modified nano-mullite is as follows: placing the nano-mullite in 10-15 times the weight concentration of 0.6 mol / L hydrochloric acid, heating it to 40-50°C, stirring and soaking it for 1-2 hours, filtering it, washing it with distilled water for 2-4 times, and then placing it in a vacuum drying oven at 80°C for drying for 30-50 minutes to obtain product A, adding 0.05-0.1 times the weight of hexadecyltrimethylammonium bromide and 6-10 times the weight of deionized water into product A, stirring it at 70-90°C for 30-40 minutes, filtering it and drying it in turn to obtain the modified nano-mullite.

2. The transparent flame-retardant polypropylene ultra-thin sheet according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 85-95 parts of polypropylene, 1.5-4 parts of organic phosphorus flame retardant, 0.4-0.6 parts of permeability enhancer, 0.3-0.8 parts of nano inorganic additive, 3-4 parts of modified polyethylene glycol, 0.2-0.3 parts of antioxidant, 2-4 parts of modified nano mullite and 0.3-0.6 parts of lubricant.

3. The transparent flame-retardant polypropylene ultra-thin sheet according to claim 2, characterized in that: The invention comprises the following raw materials in parts by weight: 90 parts of polypropylene, 2.75 parts of organic phosphorus flame retardant, 0.5 parts of permeability enhancer, 0.55 parts of nano inorganic additive, 4 parts of modified polyethylene glycol, 0.2 parts of antioxidant, 3 parts of modified nano mullite and 0.3 parts of lubricant.

4. The transparent flame-retardant polypropylene ultra-thin sheet according to claim 1, characterized in that: The polypropylene is homopolymer polypropylene or copolymer polypropylene, and its melt index (MFI) is 1-5 g / 10 min. The organic phosphorus flame retardant includes at least one of triphenyl phosphate and triphenyl phosphate derivatives. The permeability enhancer includes at least one of sorbitol, polyvinyl cyclobutane, and sodium benzoate.

5. The transparent flame-retardant polypropylene ultra-thin sheet according to claim 1, characterized in that: The nano inorganic additive comprises one or more combinations of nano calcium carbonate, nano talc, nano barium sulfate and nano aluminum oxide, and the average particle size of the nano inorganic additive is 10-100 nm.

6. The transparent flame-retardant polypropylene ultra-thin sheet according to claim 1, characterized in that: The lubricant includes at least one of bisphenol A and bisphenol A derivatives, and the lubricant includes at least one of zinc stearate and zinc stearate derivatives.

7. The method for preparing the transparent flame-retardant polypropylene ultra-thin sheet according to any one of claims 1 to 6, characterized in that: The steps include: Weigh each raw material according to a ratio, and mix the raw materials to obtain a mixture; The mixture is melt-extruded through a twin-screw extruder, cooled and pelletized to obtain particles; The particles are heated and melted, and extruded through a die to obtain a transparent flame-retardant polypropylene sheet; The transparent flame-retardant polypropylene sheet is subjected to heat pressing by a heat press to obtain a transparent flame-retardant polypropylene plate; The transparent flame-retardant polypropylene sheet is uniaxially stretched to obtain a transparent flame-retardant polypropylene ultra-thin sheet.

8. The method for preparing the transparent flame-retardant polypropylene ultra-thin sheet according to claim 7, characterized in that: The steps of uniaxial stretching are as follows: Preheating: The unstretched polypropylene sheet is passed through a preheating device to raise its temperature to a temperature close to the glass transition temperature; Stretching: The preheated polypropylene sheet is passed through a stretching device and stretched in one direction to orient its molecular chains to form a uniaxially stretched polypropylene sheet; Heat setting: The uniaxially stretched polypropylene sheet is passed through a heat setting device to raise its temperature to near the melting point, and then rapidly cooled to fix its molecular chains in the stretched state; Cutting: The heat-set polypropylene sheet is passed through a cutting device and cut into the required size and shape.

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