Polyimide-coated aluminum hypophosphite flame retardant as well as preparation method and application thereof

Abstract

The invention relates to the field of flame-retardant substances, in particular to a polyimide-coated aluminum hypophosphite flame retardant as well as a preparation method and application thereof. The preparation method comprises the following steps: cutting polyimide by using a splitting machine, dipping the cut polyimide in liquid nitrogen for 1 min, and crushing the polyimide in an extrusion crusher; observing particles of the obtained powder to be planar by using a scanning electron microscope, wherein the average particle size is 10-20 microns; dissolving the polyimide resin powder in dimethylacetamide; dispersing aluminum hypophosphite in absolute ethyl alcohol, and adding an acetic acid aqueous solution to adjust the pH value to 6; adding the polyimide dimethyl acetyl solution into the aluminum hypophosphite absolute ethyl alcohol solution, raising the temperature to 60-80 DEG C, and stirring for 30-60 minutes; and carrying out spray drying on the solution to obtain the polyimide-coated aluminum hypophosphite flame retardant.

Description

Technical Field

[0001] The invention relates to the field of flame retardant materials, in particular to a polyimide-coated aluminum hypophosphite flame retardant and a preparation method and application thereof. Background Art

[0002] Aluminum hypophosphite (AHP) is a highly efficient halogen-free inorganic phosphorus flame retardant with a phosphorus content of up to 41.9% and good thermal stability. It is widely used in flame retardant polypropylene, polyethylene, nylon, polyurethane and other polymer materials. AHP decomposes under heat. The flame retardant mechanism in the gas phase is mainly that AHP decomposes to produce PH3 and H2O gases to dilute the concentration of combustible gases and reduce combustion efficiency. In addition, the free radical scavengers such as PO•, PO2•, PO2 3- and PO4 3- produced by pyrolysis capture the strong free radicals such as H• and HO• produced by the breakage of polymer chains in the gas phase, terminating the chain reaction. The condensed phase flame retardant mechanism is mainly that AHP decomposes at 300-350℃ to produce aluminum hydrogen phosphate, which is then decomposed into aluminum pyrophosphate and aluminum phosphate to form carbon on the surface of the composite material, isolating the surrounding combustible gases and oxygen, protecting the underlying polymer from the effects of heat and oxygen, and improving thermal stability and flame retardancy.

[0003] However, AHP also has some shortcomings. It is slightly soluble in water, easy to migrate, releases toxic gas PH3 when heated and is prone to spontaneous combustion. It is in a phase separation state with most polymer matrices, affecting the mechanical properties of the material.

[0004] On the other hand, when AHP is used in some polymer resins, there is a lack of carbon source and the flame retardant efficiency is reduced.

[0005] On December 10, 2024, with "polyimide and aluminum hypophosphite and flame retardant" as abstract keywords, the option of allowing synonym expansion was checked, and a search was conducted in the Chinese Patent Publication Database, and the following documents were found: CN108794863A A high-efficiency flame-retardant cable material and a preparation method thereof; the high-efficiency flame-retardant cable material comprises the following raw materials: low-density polyethylene, ethylene-vinyl acetate copolymer, modified aluminum hypophosphite, morpholine guanidine, stearic acid ethylene glycol monoester, polypropylene wax, photocatalyst, aluminum-magnesium alloy powder, and antioxidant; the modified aluminum hypophosphite is a mixture of aluminum hypophosphite, methylene diaminoethane, phenyl silicone oil, and polyimide in a mass ratio of 6:2:9:1; the preparation method of the high-efficiency flame-retardant cable material comprises the following steps: S1, weighing the raw materials; S2, dispersing morpholine guanidine into the modified aluminum hypophosphite; S3, mixing the raw materials; S4, drawing and pelletizing, extruding, and granulating to obtain the high-efficiency flame-retardant cable material. The cable material proposed by the invention has a reasonable formula, a small amount of raw materials added for flame retardancy, a simple preparation method, and the obtained cable material has excellent aging resistance, antibacterial property, corrosion resistance, flame retardancy and mechanical properties.

[0006] CN108794863A A high-efficiency flame-retardant cable material and a preparation method thereof; the high-efficiency flame-retardant cable material comprises the following raw materials: low-density polyethylene, ethylene-vinyl acetate copolymer, modified aluminum hypophosphite, morpholine guanidine, stearic acid ethylene glycol monoester, polypropylene wax, photocatalyst, aluminum-magnesium alloy powder, antioxidant; the modified aluminum hypophosphite is a mixture of aluminum hypophosphite, methylene diamino formate, phenyl silicone oil, and polyimide in a mass ratio of 6:2:9:1; the preparation method of the high-efficiency flame-retardant cable material comprises the following steps: S1, weighing the raw materials; S2, dispersing morpholine guanidine into the modified aluminum hypophosphite; S3, mixing the raw materials; S4, drawing and pelletizing, extruding, and granulating to obtain the high-efficiency flame-retardant cable material. The cable material proposed by the present invention has a reasonable formula, a small amount of raw materials added to play a flame-retardant role, a simple preparation method, and the obtained cable material has excellent aging resistance, antibacterial property, corrosion resistance, flame retardancy and mechanical properties.

[0007] CN112874077B discloses a highly flame-retardant and antistatic double-layer fabric and a preparation method thereof; the polyamide layer is mainly made of an aluminum-based composite, isobutyl aluminum hypophosphite and polyamide, the aluminum-based composite and isobutyl aluminum hypophosphite are blended, the aluminum ions in the isobutyl aluminum hypophosphite and the aluminum ions in the aluminum-based composite form a metal network, which can quickly conduct away the charges stored on the surface of the fabric to prevent the generation of static electricity, while the polyamide is thermally decomposed to produce isocyanate and alcohol structures, the isocyanate reacts with the aluminum-based composite to form a polyimide structure, which can make the carbon layer generated by the combustion of isobutyl aluminum hypophosphite more compact, and improve the flame retardant performance of the fabric. The double-layer fabric disclosed by the invention has good antistatic performance, effectively avoids the accumulation of charges on the fabric, can quickly conduct away the static electricity generated by friction, and has good flame retardant performance, and has high practicality and industrial production value.

[0008] CN112874077A discloses a highly flame-retardant and antistatic double-layer fabric and a preparation method thereof; the double-layer fabric comprises a base fabric layer and a polyamide layer, the polyamide layer is mainly made of an aluminum-based composite, isobutyl aluminum hypophosphite and polyamide, the aluminum-based composite and isobutyl aluminum hypophosphite are blended, the aluminum ions in the isobutyl aluminum hypophosphite and the aluminum ions in the aluminum-based composite form a metal network, which can quickly conduct away the charges stored on the surface of the fabric to prevent the generation of static electricity, while the polyamide is thermally decomposed to produce isocyanate and alcohol structures, the isocyanate reacts with the aluminum-based composite to form a polyimide structure, which can make the carbon layer generated by the combustion of isobutyl aluminum hypophosphite more compact, and improve the flame retardant performance of the fabric. The double-layer fabric disclosed by the invention has good antistatic performance, effectively avoids the accumulation of charges on the fabric, can quickly conduct away the static electricity generated by friction, and has good flame retardant performance, and has high practicality and industrial production value.

[0009] CN106009667A A high temperature resistant and highly flame retardant polyimide film and a preparation method thereof; the film is made of the following raw materials in parts by weight: 50-55 o-phenylenediamine, 105-115 pyromellitic anhydride, 25-30 N,N-dimethylacetamide, 28-34 furfural resin, 8-14 nano silicon nitride, 5-10 colemanite, 13-17 tris(2-chloropropyl) phosphate, 6-9 antimony trioxide, 10-15 hexachlorocyclopentadiene, 7-11 aluminum hypophosphite, 12-18 melamine formaldehyde resin, 3-6 N-phenylmaleimide, 2-5 dimethylbiphenyl diisocyanate, 1-2 ammonium chloride and 1-2 p-hydroxybenzenesulfonic acid. The inorganic raw materials such as colemanite added in the present invention cooperate with the organic raw materials such as furfural resin and act as heat-resistant modifiers in the polyimide film, thereby improving the high temperature resistance, chemical resistance and impact resistance of the material; the inorganic raw materials such as aluminum hypophosphite added cooperate with the organic raw materials such as hexachlorocyclopentadiene and act as flame-retardant modifiers in the polyimide film, thereby making the prepared material have high flame retardancy and self-extinguishing properties.

[0010] CN110128822A A flame retardant polyimide resin and its preparation method; it is prepared from the following raw materials in parts by weight: 10-20 parts of diamine; 30-100 parts of dianhydride; 3-5 parts of flame retardant modifier; 1-2 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-phosphoethane. The preparation method is as follows: aluminum hypophosphite and antimony trioxide are ground and mixed evenly with a ball mill, and after being taken out, hexachlorocyclopentadiene is added, and then melamine formaldehyde resin is added to obtain a flame retardant modifier; under nitrogen protection, a diamine monomer is added to a solvent, and after stirring and dissolving, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-phosphorylethane is added, and dianhydride is added in batches, reacted at room temperature, and then a flame retardant modifier is added, and after ultrasonic stirring, the reaction is carried out; a film is applied on a glass plate, the temperature is increased, and after film formation, the film is naturally cooled to room temperature to obtain a polyimide resin. The preparation method of the present invention is simple, and the flame retardant polyimide resin obtained has excellent flame retardancy and mechanical properties.

[0011] CN117511029A A photovoltaic irradiated halogen-free polyolefin cable material and a preparation method thereof; polyethylene is used as the main system of the formula, and methyl silicone rubber with excellent insulation, aging resistance and high temperature resistance is added; ethylene-vinyl acetate copolymer has the characteristics of being able to improve the flexibility and impact resistance of the system, and it also has excellent ultraviolet resistance and is suitable for outdoor use; polyimide can be used as a lubricant in the present invention, and it can be cross-linked with polyethylene resin to enhance the mechanical properties of the system, and can balance the reduced fluidity of the product caused by the addition of methyl silicone rubber, reducing the difficulty of processing; aluminum hypophosphite and tributyl phosphate are used as flame retardants in this system, and tributyl phosphate can also increase the stability of the polyolefin system processing process; the cable material prepared by the formula of the present invention does not contain halogen and has good finished product performance; and the method is simple to prepare and is suitable for mass production.

[0012] The above technical components are too many and the cost is too high.

[0013] On December 10, 2024, an abstract search for "polyimide and aluminum hypophosphite and flame retardant" was conducted on CNKI, and the following was found: "Study on the flame retardancy and thermal stability of enhanced bisphenol A epoxy resin cured products"; the paper studied that both diethyl aluminum hypophosphite (Al Pi) and melamine polyphosphate (MPP) have good flame retardancy, but when used alone as a flame retardant, it will inevitably reduce the initial decomposition temperature of the material. At the same time, the addition amount of a single component is often large and the dispersion is poor.

[0014] The above technical components are too many and the cost is too high.

[0015] On December 10, 2024, a search was conducted on the website of the United States Patent and Trademark Office for "Polyimide with aluminum hypophosphite with flameretardant", and no relevant literature was found; the search URL was https: / / ppubs.uspto.gov / pubwebapp / .

[0016] On December 10, 2024, a search was conducted on the Korean Patent Office for "Polyimide and aluminum hypophosphite and flameretardant", and no relevant literature was found; the search URL was http: / / eng.kipris.or.kr / enghome / main.jsp.

[0017] On December 10, 2024, a search was conducted on WIPO's https: / / patentscope2.wipo.int / for "Polyimide and aluminum hypophosphite and flameretardant" and the following was found: Appl.No202110289488.4 Highly flame-retardant and antistatic double-layer fabric and its preparation method; the double-layer fabric comprises a base fabric layer and a polyamide layer, the polyamide layer is mainly prepared from an aluminum-based compound, isobutyl aluminum hypophosphite and polyamide, the aluminum-based compound and isobutyl aluminum hypophosphite are blended, wherein the aluminum ion isobutyl aluminum hypophosphite and the aluminum ion-based compound in the aluminum form a metal network, which can quickly conduct away the charges accumulated on the surface of the fabric to avoid the generation of static electricity; at the same time, polyamide thermally decomposes to form isocyanate and alcohol structures, and the isocyanate reacts with the aluminum-based compound to form a polyimide structure, so that the carbon layer generated by the combustion of isobutyl aluminum hypophosphite is dense, and the flame can improve the delay of the fabric. The double-layer fabric of the invention has good antistatic performance, effectively avoids charge accumulation on the fabric, can quickly conduct away static electricity generated by friction, and has good flame retardant performance, and has high practicality and industrial production value.

[0018] Appl.No 201810790986.5 High-efficiency flame-retardant cable material and preparation method thereof; the high-efficiency flame-retardant cable material comprises low-density polyethylene, ethylene-vinyl acetate copolymer, modified aluminum hypophosphite, morpholine morpholine, ethylene glycol monostearate, polypropylene wax, photocatalyst, aluminum-modified aluminum hypophosphite is prepared by mixing magnesium alloy powder and antioxidant with methylene diamino formate, phenyl silicone oil and polyimide. A method for preparing a high-efficiency flame-retardant cable material, according to a mass ratio of 6:2:9:1, comprises the following steps: S1, weighing raw materials; S2, dispersing morpholine into modified aluminum hypophosphite; S3, mixing raw materials; S4, stretching, slicing, extruding and granulating to obtain a high-efficiency flame-retardant cable material. The high-efficiency flame-retardant cable material and its preparation method have a reasonable formula, and the amount of raw material added plays a flame-retardant role. - Low flame retardant effect, simple preparation method, the obtained cable material has high aging resistance, antibacterial, corrosion, fire resistance and excellent mechanical properties.

[0019] Appl.No 201910350656.9 Flame retardant polyimide resin and preparation method thereof; the flame retardant polyimide resin is made of the following raw materials in parts by weight: 10-20 parts of diamine; 30-100 parts of dianhydride; 3-5 parts of flame retardant modifier, and 1-2 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-phosphoethane. The preparation method comprises the following steps: grinding aluminum hypophosphite and antimony trioxide with a ball mill to mix them uniformly, taking them out, adding hexachlorocyclopentadiene, adding melamine formaldehyde resin, and obtaining a flame retardant modifier; adding a diamine monomer to a solvent under nitrogen protection, stirring and dissolving, adding 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-phosphorylethane, adding dianhydride in batches, reacting at room temperature, adding a flame retardant modifier, and reacting after ultrasonic stirring; coating a film on a glass plate, heating after film formation, and naturally cooling to room temperature to obtain a polyimide resin. The preparation method of the present invention is simple, and the obtained flame retardant polyimide resin has excellent flame retardant properties and mechanical properties.

[0020] The above technical components are too many and the cost is too high.

[0021] On December 10, 2024, a search was conducted on the Japan Patent Office website https: / / www.j-platpat.inpit.go.jp / for "Polyimide and aluminum hypophosphite and flameretardant", but no relevant literature was found.

[0022] Completely different from the concept of this patent. Summary of the invention

[0023] Purpose of the invention: To provide a better polyimide-coated aluminum hypophosphite flame retardant and its preparation method and use. The specific purpose can be seen in the multiple substantial technical effects of the specific implementation part.

[0024] In order to achieve the above purpose, the present invention adopts the following technical solutions: The flame retardant of polyimide-coated aluminum hypophosphite is characterized in that it is a product obtained by coating and modifying aluminum hypophosphite with polyimide.

[0025] Use of polyimide as a substance for preventing aluminum hypophosphite from releasing toxic PH3 gas.

[0026] The invention discloses a method for coating aluminum hypophosphite with polyimide to improve the compatibility of aluminum hypophosphite with polymer resin.

[0027] The preparation method of a flame retardant of polyimide-coated aluminum hypophosphite is characterized in that: The following steps are included: The polyimide was cut by a slitting machine, immersed in liquid nitrogen for 1 minute, and then crushed in an extrusion mill. The obtained powder was observed by scanning electron microscope to be planar particles with an average particle size of 10-20 μm. Dissolving the polyimide resin powder in dimethylacetamide; Disperse aluminum hypophosphite in anhydrous ethanol and add acetic acid aqueous solution to adjust the pH to 6; Add the polyimide dimethylacetyl solution to the aluminum hypophosphite anhydrous ethanol solution, raise the temperature to 60-80°C and stir for 30-60 minutes; The polyimide-coated aluminum hypophosphite flame retardant can be obtained by spray drying the above solution.

[0028] The present invention adopting the above technical solution has the following beneficial effects compared with the prior art: Therefore, the present invention uses polyimide to coat and modify aluminum hypophosphite, which on the one hand improves the compatibility of aluminum hypophosphite with polymer resin and improves the mechanical properties of flame retardant materials; on the other hand, the introduction of carbon source can greatly improve the flame retardant efficiency of flame retardant, reduce the amount of flame retardant used, and thus reduce the flame retardant cost of the product. And the cost is extremely low. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to further illustrate the present invention, the following is further described in conjunction with the accompanying drawings: Figure 1 A diagram of the steps of the invention. DETAILED DESCRIPTION

[0030] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. In the description of the present invention, it should be noted that the orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "top", "bottom", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal connection of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific circumstances.

[0031] After cutting with a slitter, it was immersed in liquid nitrogen for 1 minute and then crushed in an extrusion mill. The obtained powder was observed by scanning electron microscope to be planar particles with an average particle size of 10-20μm; Dissolve the above PI resin powder in a certain amount of dimethylacetamide; AHP was dispersed in anhydrous ethanol and the pH was adjusted to 6 by adding acetic acid aqueous solution; Add PI dimethylacetyl solution to AHP anhydrous ethanol solution, heat to 60-80℃ and stir for 30-60min; The PI-coated AHP flame retardant can be obtained by spray drying the above solution.

[0032] Aluminum hypophosphite (AHP) is a highly efficient halogen-free inorganic phosphorus flame retardant with a phosphorus content of up to 41.9% and good thermal stability. It is widely used in flame retardant polypropylene, polyethylene, nylon, polyurethane and other polymer materials. AHP decomposes under heat. The flame retardant mechanism in the gas phase is mainly that AHP decomposes to produce PH3 and H2O gases to dilute the concentration of combustible gases and reduce combustion efficiency. In addition, the free radical scavengers such as PO•, PO2•, PO2 3- and PO4 3- produced by pyrolysis capture the strong free radicals such as H• and HO• produced by the breakage of polymer chains in the gas phase, terminating the chain reaction. The condensed phase flame retardant mechanism is mainly that AHP decomposes at 300-350℃ to produce aluminum hydrogen phosphate, which is then decomposed into aluminum pyrophosphate and aluminum phosphate to form carbon on the surface of the composite material, isolating the surrounding combustible gases and oxygen, protecting the underlying polymer from the effects of heat and oxygen, and improving thermal stability and flame retardancy.

[0033] However, AHP also has some shortcomings. It is slightly soluble in water, easy to migrate, releases toxic gas PH3 when heated and is prone to spontaneous combustion. It is in a phase separation state with most polymer matrices, affecting the mechanical properties of the material.

[0034] On the other hand, AHP is used in some polymer resins, but lacks a carbon source and has a reduced flame retardant efficiency. Therefore, the present invention uses polyimide to coat and modify aluminum hypophosphite, which, on the one hand, improves the compatibility of aluminum hypophosphite with the polymer resin and improves the mechanical properties of the flame retardant material; on the other hand, the introduction of a carbon source can greatly improve the flame retardant efficiency of the flame retardant, reduce the amount of the flame retardant used, and thereby reduce the flame retardant cost of the product.

[0035] After testing, it was found that aluminum hypophosphite is highly compatible with polymer resin, and this material greatly improves the mechanical properties of flame retardant materials and can enhance the flame retardant effect.

[0036] The basic principle, main features and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the protection required.

Claims

1. A flame retardant of polyimide coated aluminum hypophosphite, characterized in that: It is a product obtained by coating and modifying aluminum hypophosphite with polyimide.

2. Use of polyimide as a substance to prevent aluminum hypophosphite from releasing toxic gas PH3.

3. The use of polyimide-coated aluminum hypophosphite to improve the compatibility of aluminum hypophosphite with polymer resin.

4. A method for preparing a flame retardant of polyimide-coated aluminum hypophosphite, characterized in that: The following steps are included: The polyimide was cut by a slitting machine, immersed in liquid nitrogen for 1 minute, and then crushed in an extrusion mill. The obtained powder was observed by scanning electron microscope to be planar particles with an average particle size of 10-20 μm. Dissolving the polyimide resin powder in dimethylacetamide; Disperse aluminum hypophosphite in anhydrous ethanol and add acetic acid aqueous solution to adjust the pH to 6; Add the polyimide dimethylacetyl solution to the aluminum hypophosphite anhydrous ethanol solution, raise the temperature to 60-80°C and stir for 30-60 minutes; The polyimide-coated aluminum hypophosphite flame retardant can be obtained by spray drying the above solution.

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