Flame-retardant polypropylene material and preparation method thereof

Abstract

The invention discloses a flame-retardant polypropylene material which comprises PP (polypropylene), HDPE (high-density polyethylene), a flexibilizer, a compatilizer, a P-series flame retardant, modified polyhedral oligomeric silsesquioxane and a derivative flame-retardant synergist of the modified polyhedral oligomeric silsesquioxane. The modified polyhedral oligomeric silsesquioxane and the derivative flame-retardant synergist thereof contain boron, an annular structure R2 with the carbon hydrogen ratio larger than 1 and two inorganic silicon cage cores, and the structures form a carbon layer, a ceramic barrier layer, a protective film or a heat-insulation coke layer and other protective layers in the combustion process, so that the anti-dripping effect is greatly improved, and meanwhile, the anti-dripping effect is greatly improved. Heat and oxygen transfer is isolated, flammable gas release is reduced, and the flame retardant property of the material is remarkably improved under the combined action of multiple mechanisms of the P-series flame retardant. Furthermore, the flame-retardant synergist of the modified polyhedral oligomeric silsesquioxane and the derivative of the modified polyhedral oligomeric silsesquioxane is matched with the P-series flame retardant to realize synergistic flame retardance, so that the flame retardance of the flame-retardant polypropylene material is improved while the dosage of the flame retardant is reduced. The flame-retardant polypropylene material provided by the invention is excellent in flame retardance.

Description

Technical Field

[0001] The present invention relates to the field of materials, and particularly to a flame-retardant polypropylene material. Background Art

[0002] Polyhedral oligomeric silsesquioxane (POSS) is a special organic amorphous material. It is a multi-cyclic organic monomer composed of a silicon framework and its embedded oxygen atoms. It is an inorganic-organic hybrid nanomaterial. The inorganic silicon cage core in POSS decomposes when heated to form a dense ceramic barrier layer, isolating the release of combustible gases and the entry of external heat into the interior, thereby delaying the further decomposition of the material. POSS shows great application potential in the field of flame retardants.

[0003] The oxygen index of the flame-retardant polypropylene (PP) material resin is only about 18, making it extremely flammable. Moreover, during the combustion process, melting droplets and dripping fire phenomena are likely to occur. When used to make cables, it is very easy to catch fire under conditions such as high voltage, heat generation, and discharge, thus requiring flame retardant treatment of PP plastics. The commonly used method is to add flame retardants to prevent the material from burning. Currently, the flame retardants used are divided into magnesium-aluminum series flame retardants, organosilicon series flame retardants, nitrogen series flame retardants, halogen series flame retardants, etc. Organosilicon series flame retardants are quite expensive; nitrogen series flame retardants are extremely easy to hydrolyze and will greatly increase the dielectric constant of PP; halogen series flame retardants cause serious air pollution during combustion, and many products have begun to limit the use of halogen series flame retardants; magnesium-aluminum series flame retardants are inexpensive, and when the filling degree reaches more than 60%, the flame retardant performance is very good, and increasing the addition amount will also increase the dielectric constant of PP. Many halogen-free systems use a main flame retardant + flame retardant synergist to improve the flame retardancy, and the selection of the synergistic flame retardant is particularly important. Adding a small amount of synergistic flame retardant can greatly improve the flame retardant performance and oxygen index of the material. Therefore, it is very necessary to develop a halogen-free, highly flame-retardant, crack-resistant and anti-dripping flame-retardant PP material. Summary of the Invention

[0004] In view of the above deficiencies of the prior art, the present invention proposes a flame-retardant polypropylene material, aiming to solve the problem of poor flame retardancy of the current flame-retardant PP materials.

[0005] The above object of the present invention is achieved by the following technical solutions:

[0006] In the first aspect of the present invention, there is provided a flame-retardant polypropylene material, and the raw materials of the flame-retardant polypropylene material are as follows in parts by weight:

[0007] 40 - 70 parts of PP,

[0008] 10 - 22 parts of HDPE,

[0009] 10 - 20 parts of toughening agent,

[0010] 10 - 20 parts of compatibilizer,

[0011] 10 - 20 parts of P - based flame retardant,

[0012] 2 - 15 parts of modified polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist,

[0013] Among them, the structure of the modified polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist is:

[0014]

[0015] Among them, R is a non - reactive group, which is isobutyl, isooctyl, ethyl, cyclohexyl, cyclopentyl, or phenyl, etc., and R1 is n - propyl or phenylene;

[0016] R2 is a cyclic structure with a carbon - hydrogen ratio greater than 1, including at least one of benzofuran group and polycyclic aromatic group.

[0017] In some embodiments of the present invention, the benzofuran group includes at least one of benzofuran group and dibenzofuran group;

[0018] And / or, the polycyclic aromatic group includes at least one of naphthalene ring group, anthracene ring group, phenanthrene ring group, acenaphthene ring group, fluorene ring group and perylene ring group.

[0019] In some embodiments of the present invention, the modified polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist is prepared by the dehydration reaction of compound 1 and compound 2 under the action of a catalyst, and the reaction route is as follows:

[0020]

[0021] In some embodiments of the present invention, the molar ratio of compound 1 to compound 2 is 2:1.

[0022] In some embodiments of the present invention, the preparation method of the modified polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist includes the following steps:

[0023] Dissolve compound 1 in an organic solvent, add an aqueous solution of compound 2 under the action of a catalyst, carry out a catalytic reaction, and then wash and dry to obtain the modified polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist;

[0024] Among them, the organic solvent includes at least one of alcohols, aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons, ethers, ketones and glycol derivatives;

[0025] The catalyst includes at least one of an acidic catalyst, a metal catalyst, and a basic catalyst.

[0026] In some embodiments of the present invention, the raw materials of the flame-retardant polypropylene material, by weight, include:

[0027] 40 - 70 parts of PP,

[0028] 10 - 20 parts of HDPE,

[0029] 10 - 15 parts of toughening agent,

[0030] 10 - 15 parts of compatibilizer,

[0031] 10 - 15 parts of P-based flame retardant,

[0032] 2 - 15 parts of modified polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist.

[0033] In some embodiments of the present invention, the toughening agent includes at least one of ethylene-octene copolymer, ethylene-propylene copolymer, EMA, and EBA.

[0034] In some embodiments of the present invention, the compatibilizer includes at least one of PE-grafted maleic anhydride, POE-grafted maleic anhydride, PP-grafted maleic anhydride, and EMA-grafted maleic anhydride.

[0035] In some embodiments of the present invention, the P-based flame retardant includes an inorganic phosphorus flame retardant or an organic phosphorus flame retardant. The inorganic phosphorus flame retardant includes at least one of red phosphorus, phosphate, and polyphosphate; the organic phosphorus flame retardant includes at least one of phosphate ester, phosphite, and phosphine oxide.

[0036] In some embodiments of the present invention, the raw materials of the flame-retardant polypropylene material further include at least one of a lubricant and an antioxidant; wherein, by weight of the raw materials, the lubricant is 0.2 - 1 part, and the antioxidant is 0.5 - 2 parts.

[0037] In the second aspect of the present invention, a method for preparing the above-mentioned flame-retardant polypropylene material is provided, including the following steps: mixing the raw materials evenly, extruding and pelletizing through an extruder to obtain pelletized materials, namely the flame-retardant polypropylene material.

[0038] In some embodiments of the present invention, the raw materials further include at least one of a lubricant and an antioxidant.

[0039] The flame-retardant polypropylene material of the present invention comprises PP, HDPE, a toughening agent, a compatibilizer, a P-based flame retardant, and a modified polyhedral oligomeric silsesquioxane and its derivative flame-retardant synergist. Since the modified polyhedral oligomeric silsesquioxane and its derivative flame-retardant synergist contain boron element, a cyclic structure R2 with a carbon-hydrogen ratio greater than 1, and two inorganic silicon cage nuclei, the boron element forms boric acid during combustion. The boric acid dehydrates and carbonizes the material surface to form a carbon layer; the two inorganic silicon cage nuclei decompose upon heating to form a dense ceramic barrier layer, isolating the release of combustible gases and the entry of external heat into the interior; the cyclic structure R2 with a carbon-hydrogen ratio greater than 1 has a high carbon-hydrogen ratio, and the benzofuran group and polycyclic aromatic group contain a large amount of carbon element. A large amount of carbon element will form a glassy protective film or heat-insulating coke layer during combustion. These protective films or coke layers can isolate air, prevent heat transfer, and reduce the release of combustible gases. These structures form protective layers such as a carbon layer, a ceramic barrier layer, a protective film, or a heat-insulating coke layer during combustion, greatly improving the anti-dripping effect. At the same time, they isolate the transfer of heat and oxygen, reduce the release of combustible gases, and the combined action of multiple mechanisms significantly improves the flame-retardant performance of the material. Further, the modified polyhedral oligomeric silsesquioxane and its derivative flame-retardant synergist cooperate with the P-based flame retardant for synergistic flame retardancy. During combustion, the Si element can rapidly react with the C element in the R2 group to generate a large number of Si-C bonds. At the same time, the B element can form a glass film on the surface of the flame-retardant PP material, and the generated boric acid dehydrates the polymer rapidly to produce a carbon layer. The B element in the modified POSS and its derivative synergistic flame retardant can also coordinate with the P element in the system to produce a synergistic effect, thereby improving the flame-retardant effect, reducing the amount of flame retardant used, and at the same time enhancing the flame-retardant performance and anti-cracking performance of the flame-retardant polypropylene material. The flame-retardant polypropylene material provided by the present invention has excellent flame-retardant performance and anti-cracking performance, and can prevent dripping during combustion. The modified POSS and its derivative flame-retardant synergist is in the state of a colorless viscous liquid, and has little influence on the performance of the flame-retardant polypropylene material when added thereto, and an excellent flame-retardant flame-retardant polypropylene material can be obtained with a relatively low addition amount. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is the molecular structure diagram of the modified POSS flame-retardant synergist 1 of the present invention;

[0041] Figure 2 is the molecular structure diagram of the modified POSS flame-retardant synergist 2 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention.

[0043] Unless otherwise specified, all technical and scientific terms used herein have the ordinary meanings ascribed to them in the field to which the claimed subject matter pertains.

[0044] PP: Polypropylene, a semi-crystalline thermoplastic polymer made from propylene monomers through addition polymerization. Polypropylene has characteristics such as being lightweight, wear-resistant, antibacterial, and easy to dye, and is widely used in fiber products such as clothing and blankets; it has good insulation properties and is used in manufacturing the casings and components of appliances such as refrigerators, washing machines, air conditioners, and televisions; it has good chemical stability, heat resistance, transparency, and mechanical properties and is used in manufacturing medical devices; it has good corrosion resistance, weather resistance, and plasticity and is used in manufacturing building and construction products.

[0045] HDPE: High Density Polyethylene, a thermoplastic polyolefin copolymerized from ethylene. It has better hardness, tensile strength, and creep resistance than low-density polyethylene; it has good abrasion resistance, electrical insulation, toughness, and cold resistance; it has good chemical stability and is insoluble in any organic solvent at room temperature, and is resistant to corrosion by acids, alkalis, and various salts; the film has low permeability to water vapor and air and low water absorption, and is widely used in gas transmission, water supply, sewage disposal, agricultural irrigation, conveying of fine particulate solids in mines, and fields such as oil fields, chemical industry, and post and telecommunications, and is particularly widely used in gas transmission.

[0046] EMA: ethylene-methyl acrylate copolymer, a copolymer made from ethylene, methyl acrylate, and a comonomer. EMA has the characteristics of being transparent, low density, and elastic, and at the same time exhibits excellent waterproof performance, chemical stability, heat resistance, and insulation performance. The application scope of this material is very wide, and it is mainly used in fields such as food packaging, pharmaceutical packaging, electronic and electrical equipment, building and automotive components.

[0047] EBA: Ethylene Butyl Acrylate, an ethylene-butyl acrylate copolymer, is a high-performance polymer material with good reactivity, crystallinity, and fluidity, good flexibility, high melting point, high thermal stability, good heat-sealing performance, good low-temperature impact resistance, strong tolerance to pigments and inorganic fillers, and good compatibility with various polymers, and is widely used in fields such as adhesives, food packaging, films, wire and cable, and plastic modification.

[0048] Polyhedral oligomeric silsesquioxane (POSS) is a special organic amorphous material. It is a polycyclic organic monomer composed of a silicon framework and its bonded oxygen atoms. It is an inorganic-organic hybrid nanomaterial. The inorganic silicon cage core in POSS decomposes when heated to form a dense ceramic barrier layer, which isolates the release of combustible gases and the entry of external heat into the interior, thereby delaying the further decomposition of the material. POSS shows great application potential in the field of flame retardants.

[0049] The oxygen index of the flame-retardant polypropylene (flame-retardant PP) material resin is only about 18, making it extremely flammable. Moreover, during the combustion process, it is prone to melting droplets and dripping fire, causing the cables made of it to catch fire easily under conditions such as high voltage, heating, and discharging, so the PP plastic needs to be flame-retarded. The commonly used method is to add flame retardants to prevent the material from burning. The currently used flame retardants are divided into magnesium-aluminum flame retardants, organosilicon flame retardants, nitrogen-based flame retardants, halogen-based flame retardants, etc. Organosilicon flame retardants are quite expensive; nitrogen-based flame retardants are extremely prone to hydrolysis and will greatly increase the dielectric constant of PP; halogen-based flame retardants cause serious air pollution during combustion; magnesium-aluminum flame retardants are inexpensive, and when the filling degree reaches more than 60%, the flame retardant performance is very good, and increasing the addition amount will also increase the dielectric constant of PP. Selection of synergistic flame retardants. Adding a small amount of synergistic flame retardants can greatly improve the flame retardant performance and oxygen index of the material. Therefore, it is very necessary to develop a flame-retardant PP material with high flame retardancy, crack resistance, and anti-dripping.

[0050] To solve the above problems, in the first aspect of the present invention, a flame-retardant polypropylene material is proposed. The raw materials of the flame-retardant polypropylene material, by weight, include:

[0051] 40 - 70 parts of PP,

[0052] 10 - 22 parts of HDPE,

[0053] 10 - 20 parts of toughening agent,

[0054] 10 - 20 parts of compatibilizer,

[0055] 10 - 20 parts of P-based flame retardant,

[0056] 2 - 15 parts of modified polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist,

[0057] Among them, the structure of the modified polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist is:

[0058]

[0059] Among them, R is a non-reactive group, such as isobutyl, isooctyl, ethyl, cyclohexyl, cyclopentyl, or phenyl, etc., R1 is n-propyl or phenylene;

[0060] R2 is a cyclic structure with a carbon-hydrogen ratio greater than 1, including at least one of benzofuran group and polycyclic aromatic group.

[0061] It can be understood that when R1 connected to Si in the inorganic silicon cage core is phenylene, due to the benzene ring in phenylene having a relatively high carbon-hydrogen ratio and carbon content, during combustion, it acts together with a large amount of Si contained in the inorganic silicon cage core to further improve the flame retardancy of the inorganic silicon cage core, thereby improving the flame retardancy of the modified polyhedral oligomeric silsesquioxane flame retardant synergist.

[0062] The flame-retardant polypropylene material of the present invention includes PP, HDPE, toughening agent, compatibilizer, P-based flame retardant, and modified polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist. Since the modified polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist contain boron element, a cyclic structure R2 with a carbon-hydrogen ratio greater than 1, and two inorganic silicon cage cores, during combustion, the boron element forms boric acid, and the boric acid dehydrates and carbonizes the material surface to form a carbon layer; the two inorganic silicon cage cores decompose upon heating to form a dense ceramic barrier layer, isolating the release of combustible gases and the entry of external heat into the interior; the cyclic structure R2 with a carbon-hydrogen ratio greater than 1 has a relatively high carbon-hydrogen ratio, and the benzofuran group and polycyclic aromatic group contain a large amount of carbon element. A large amount of carbon element will form a glassy protective film or heat-insulating coke layer during combustion. These protective films or coke layers can isolate air, prevent heat transfer, and reduce the release of combustible gases. These structures form protective layers such as carbon layer, ceramic barrier layer, protective film or heat-insulating coke layer during combustion, greatly improving the anti-dripping effect. At the same time, isolating heat and oxygen transfer, reducing the release of combustible gases, and the combined action of multiple mechanisms significantly improve the flame retardancy of the material. Further, the modified polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist cooperate with the P-based flame retardant to achieve synergistic flame retardancy. During combustion, the Si element and the C element in the R2 group can quickly react to generate a large number of Si-C bonds. At the same time, the B element can form a glass film on the surface of the flame-retardant PP material, and the generated boric acid dehydrates the polymer rapidly, generating a carbon layer. The B element in the modified POSS and its derivative synergistic flame retardant can also coordinate with the P element in the system to produce a synergistic effect, thereby improving the flame retardancy effect, reducing the amount of flame retardant used while enhancing the flame retardancy and anti-cracking performance of the flame-retardant polypropylene material. The flame-retardant polypropylene material provided by the present invention has excellent flame retardancy and anti-cracking performance, and can prevent dripping during combustion. The modified POSS and its derivative flame retardant synergist is in the state of a colorless viscous liquid, has little impact on the performance of the flame-retardant polypropylene material when added, and an excellent flame-retardant polypropylene material with excellent flame retardancy can be obtained with a relatively low addition amount.

[0063] Further, the benzofuran group includes at least one of a benzofuran group and a dibenzofuran group.

[0064] The phenyl group has a high carbon-hydrogen ratio and a high carbon content, which can slow down the spread rate of the flame during combustion. When the flame is removed, it can quickly self-extinguish, reducing the duration and intensity of combustion. The furan group has oxygen elements that do not participate in combustion while having a high carbon content. The benzofuran group or dibenzofuran group formed by the combination of the two has both a high carbon-hydrogen ratio and low combustion elements. The two work together to form a glassy protective film or an insulating coke layer during combustion. These protective films or coke layers can isolate air, prevent heat transfer, reduce the content of combustibles, and indirectly promote carbon formation.

[0065] In some embodiments, R2 is a benzofuran group.

[0066] In some embodiments, the polycyclic aromatic group includes at least one of a naphthalene ring group, an anthracene ring group, a phenanthrene ring group, an acenaphthene ring group, a fluorene ring group, and a perylene ring group.

[0067] The naphthalene ring group, anthracene ring group, phenanthrene ring group, acenaphthene ring group, fluorene ring group, and perylene ring group have a high carbon-hydrogen ratio and contain a large amount of carbon elements, and are more likely to form a glassy protective film or an insulating coke layer during combustion.

[0068] In some embodiments, R2 is a naphthalene ring group.

[0069] Further, the modified polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist are prepared by the dehydration reaction of compound 1 and compound 2 under the action of a catalyst. The reaction route is as follows:

[0070]

[0071] Further, the molar ratio of compound 1 to compound 2 in the above reaction process is 2:1.

[0072] The polyhedral oligomeric silsesquioxane of compound 1 has a large spatial structure. In the reaction, it is necessary to ensure that compound 2 has a sufficiently small steric hindrance so that it can react with compound 1 to obtain compound 3, the modified polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist. During the reaction process, each compound 2 is connected to 2 compound 1s, that is, the molar ratio of compound 1 to compound 2 is 2:1, which ensures sufficient space for compound 3 and realizes the structural stability of compound 3 at the same time; compound 2 contains 2 hydroxyl groups, and the 2 hydroxyl groups of 1 compound 2 are respectively combined with 1 amino group in 2 compound 1s for dehydration reaction to obtain compound 3. The substances required in the overall reaction are single, the operation is simple, and it is easy to achieve.

[0073] In some embodiments, Compound 1 is aminopropyl heptaisobutylcaged polyhedral oligomeric silsesquioxane.

[0074] In some embodiments, Compound 1 is aminophenyl heptaisobutylcaged polyhedral oligomeric silsesquioxane.

[0075] In some embodiments, Compound 2 is benzo[B]naphtho[2,3-D]furan-2-hydroxyboronic acid.

[0076] In some embodiments, Compound 2 is dibenzofuran-4-boronic acid.

[0077] In some embodiments, the structural formula of Compound 3 is:

[0078]

[0079] The following is designated as Modified POSS Flame Retardant Synergist 1.

[0080] In some embodiments, the structural formula of Compound 3 is:

[0081]

[0082] The following is designated as Modified POSS Flame Retardant Synergist 2.

[0083] Furthermore, the preparation method of Compound 3 comprises the following steps:

[0084] Dissolve Compound 1 in an organic solvent, add an aqueous solution of Compound 2 under the action of a catalyst, carry out a catalytic reaction, and then wash and dry to obtain Compound 3;

[0085] Among them, the organic solvent includes at least one of alcohols, aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons, ethers, ketones, and glycol derivatives;

[0086] The catalyst includes at least one of acidic catalysts, metal catalysts, and basic catalysts..

[0087] In some embodiments, the catalyst is acetic acid.

[0088] In some embodiments, the solvent is ethanol.

[0089] Furthermore, the raw materials of the flame-retardant polypropylene material, by weight, include:

[0090] 40 - 70 parts of PP,

[0091] 10 - 20 parts of HDPE,

[0092] 10 - 15 parts of toughening agent,

[0093] 10 - 15 parts of compatibilizer,

[0094] 10 - 15 parts of P - based flame retardant,

[0095] 2 - 15 parts of modified polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist.

[0096] Reducing the amount of P - based flame retardant can further improve the mechanical properties of the flame - retardant polypropylene material.

[0097] Furthermore, the toughening agent includes at least one of ethylene - octene copolymer, ethylene - propylene copolymer, EMA, and EBA.

[0098] The toughening agent can increase the flexibility of the adhesive film layer, significantly increase the flexibility of the material, making it not easy to break under external force, improve the impact resistance and fatigue resistance of the material, effectively prevent the expansion of cracks, thereby extending the service life of the material, can weaken the interaction between the molecular chains of the polymer material, reduce the friction between molecular chains, increase the movement ability of polymer molecular chains, and thus improve the processing fluidity and molding performance of the material.

[0099] It can be understood that the toughening agent includes but is not limited to ethylene - octene copolymer, ethylene - propylene copolymer, EMA, and EBA.

[0100] In some embodiments, the toughening agent is preferably ethylene - octene copolymer.

[0101] Furthermore, the compatibilizer includes at least one of PE - grafted maleic anhydride, POE - grafted maleic anhydride, PP - grafted maleic anhydride, and EMA - grafted maleic anhydride.

[0102] The compatibilizer forms a bridge between the matrix resin and the flame retardant, improves their interfacial compatibility and adhesiveness, enables the flame retardant to be more evenly dispersed in the matrix, thereby improving the filling rate and flame - retardant effect, enhancing the overall performance of the cable, and the compatibilizer can reduce the incompatibility problems during the production process, thereby improving the production process and increasing the production efficiency.

[0103] Furthermore, the P - based flame retardant includes inorganic phosphorus flame retardant or organic phosphorus flame retardant, the inorganic phosphorus flame retardant includes at least one of red phosphorus, phosphate, and polyphosphate; the organic phosphorus flame retardant includes at least one of phosphate ester, phosphite, and phosphine oxide.

[0104] It can be understood that the phosphorus - based flame retardant includes but is not limited to aluminum hypophosphite, calcium hypophosphite, aluminum diethyl phosphinate, aluminum methyl ethyl phosphinate, and aluminum phenyl phosphinate.

[0105] In some embodiments, the P - based flame retardant is preferably aluminum diethyl phosphinate.

[0106] Furthermore, the raw materials of the flame-retardant polypropylene material further include at least one of a lubricant and an antioxidant; wherein, based on parts by weight, the lubricant is 0.2 - 1 part, and the antioxidant is 0.5 - 2 parts.

[0107] In some embodiments, the antioxidant includes, but is not limited to, asymmetric hindered phenol antioxidants, aromatic amine antioxidants, thioether antioxidants, and phosphite antioxidants.

[0108] The hindered phenol antioxidants include, but are not limited to, antioxidant 1010 (pentaerythritol tetrakis [β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate]), BHT (2,6-di-tert-butyl-p-cresol), antioxidant 1076 (n-octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate);

[0109] The aromatic amine antioxidants include, but are not limited to, diphenylamine, p-phenylenediamine, and dihydroquinoline and their derivatives or polymers, such as: antioxidant 445 (4,4'-bis(α,α-dimethylbenzyl) diphenylamine);

[0110] The thioether antioxidants include, but are not limited to, DLTP (dilauryl thiodipropionate), DSTDP (distearyl thiodipropionate), DSTP (octadecyl thiodipropionate);

[0111] The phosphite antioxidants include, but are not limited to, antioxidant 168 (tris[2,4-di-tert-butylphenyl] phosphite), antioxidant 618 (pentaerythritol diphosphite dioctadecyl ester), antioxidant 626 (bis[2,4-di-tert-butylphenyl] pentaerythritol diphosphite).

[0112] By adding antioxidants, it is beneficial to the antioxidant performance and aging resistance of the polymer material, and extends the service life of the polymer material.

[0113] In some embodiments, the lubricant includes, but is not limited to, PTFE powder, zinc stearate, magnesium stearate, silicone, calcium stearate, or ethylene bisstearamide. By adding the lubricant, it is beneficial to make the mixing of various raw materials more uniform, while improving the fluidity of the polymer resin, reducing the friction coefficient, making the surface of the product smoother, improving the processing efficiency, and also improving the transparency and gloss of the plastic.

[0114] In the second aspect of the present invention, there is provided a method for preparing the above-mentioned flame-retardant polypropylene material, including the following steps: mixing the raw materials, namely PP, HDPE, toughening agent, compatibilizer, P-based flame retardant, and modified polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist uniformly, and extruding and pelletizing through an extruder to obtain pellet material, namely the flame-retardant polypropylene material.

[0115] Furthermore, the raw materials further include at least one of a lubricant and an antioxidant.

[0116] The content of the present invention will be explained below through specific examples and data.

[0117] The information of the raw materials involved in the specific implementation part is shown in Table 1:

[0118] Table 1 Information of raw materials in examples and comparative examples

[0119]

[0120]

[0121] The thermoplastic polyurethane elastomer materials prepared in the above examples and comparative examples were made into injection molded sheets or compression molded sheets, and were subjected to flame retardant grade, oxygen index, tensile strength, elongation at break, dielectric constant, 110 °C thermal shock, 130 °C thermal shock, and 150 °C thermal shock tests. The test standards are as follows:

[0122] (1) Flame retardant grade test

[0123] According to GB / T 5455-2014, the specimens were subjected to a vertical burning grade test. The samples were cut according to the specified dimensions and tested under the specified conditions, and key parameters such as the burning time limit and residual substances were monitored.

[0124] (2) Whether it drips when testing the flame retardant grade

[0125] Whether it drips when testing the flame retardant grade was tested according to the UL94 standard. The thickness of the sample sheet was 3 mm, and the test temperature was 23 ± 2 °C. The UL94 vertical burning test device of Jiangsu Zhengrui Taibang Electronic Co., Ltd. was used for the test.

[0126] (3) Oxygen index

[0127] According to GB / T 2406.2-2009, the specimen size was prepared according to Type IV specimens. The test was carried out according to Method A - top surface ignition method. The oxygen index tester device of Nanjing Jiangning Fangshang Analytical Instrument Equipment Factory was used for the test.

[0128] (4) Tensile strength and elongation at break

[0129] The test was carried out according to Article 9 of GB 1040—2008. The test temperature was 23 ± 2 °C. The tensile test was carried out using a standard dumbbell-shaped specimen with a tensile speed of 250 mm / min. The microcomputer-controlled electronic universal material tensile machine of Dongguan High-Speed Rail Testing Co., Ltd. was used to test the tensile strength and elongation at break of 5 specimens, and the results were averaged.

[0130] (5) 110 - 150 °C thermal shock

[0131] Test according to Appendix A of GB / T 32129-2015 standard. The test temperature is 23±2°C, and the weight of the weight is 2 kg. Use the heat shock test device of Hebei Zhongke Beigong Test Instrument Co., Ltd. to test 3 samples at each temperature.

[0132] (6) Dielectric constant

[0133] Test according to GB / T 1409-2006 standard. Place the medium to be tested between parallel plate capacitors to ensure that there are no bubbles or impurities between the medium and the electrodes. Turn on the power supply and voltmeter again, record the reading U of the voltmeter, and calculate the dielectric constant ε = C / C0 = U0 / U1 according to the definition of the dielectric constant.

[0134] The test results are shown in Table 3.

[0135] Example 1:

[0136] 2 mol of aminopropyl heptaisobutylcage polyhedral oligomeric silsesquioxane is dissolved in 100 ml of tetrahydrofuran solution. Add 0.2 mol of acetic acid catalyst to the solution, and add 1 mol of benzo[B]naphtho[2,3-D]furan-2-ylboronic acid under stirring. Stir and react for 2-4 h, stop the reaction, rotary evaporate under reduced pressure, wash with water, and dry to obtain modified POSS flame retardant synergist 1;

[0137] Mix 70 parts of PP, 20 parts of HDPE, 20 parts of POE, 20 parts of PE-grafted maleic anhydride, 10 parts of modified POSS flame retardant synergist 1, 10 parts of aluminum diethylphosphinate, 0.5 part of lubricant, and 0.5 part of antioxidant evenly, and granulate by twin-screw extrusion at 180°C to obtain a flame-retardant polypropylene preform, and then dry at 80°C to obtain a high-flame-retardant, crack-resistant, halogen-free flame-retardant polypropylene material.

[0138] Example 2:

[0139] The preparation method is the same as that of Example 1, except that:

[0140] Mix 40 parts of PP, 10 parts of HDPE, 10 parts of POE, 10 parts of PE-grafted maleic anhydride, 15 parts of modified POSS flame retardant synergist 1, 20 parts of aluminum diethylphosphinate, 0.5 part of lubricant, and 0.5 part of antioxidant evenly, and granulate by twin-screw extrusion at 180°C to obtain a flame-retardant polypropylene preform, and then dry at 80°C to obtain a high-flame-retardant, crack-resistant, halogen-free flame-retardant polypropylene material.

[0141] Example 3:

[0142] The preparation method is the same as that of Example 1, except that:

[0143] Mix 55 parts of PP, 15 parts of HDPE, 15 parts of POE, 15 parts of maleic anhydride grafted PE, 2 parts of modified POSS flame retardant synergist 1, 10 parts of aluminum diethylphosphinate, 0.5 part of lubricant, and 0.5 part of antioxidant evenly, and granulate through a twin-screw extruder at 180 °C to obtain a flame-retardant polypropylene preform. Then, dry it at 80 °C to obtain a high-flame-retardant, crack-resistant, halogen-free flame-retardant polypropylene material.

[0144] Example 4:

[0145] The preparation method is the same as that of Example 1, except that:

[0146] Mix 70 parts of PP, 10 parts of HDPE, 10 parts of POE, 10 parts of maleic anhydride grafted PE, 10 parts of modified POSS flame retardant synergist 1, 15 parts of aluminum diethylphosphinate, 0.5 part of lubricant, and 0.5 part of antioxidant evenly, and granulate through a twin-screw extruder at 180 °C to obtain a flame-retardant polypropylene preform. Then, dry it at 80 °C to obtain a high-flame-retardant, crack-resistant, halogen-free flame-retardant polypropylene material.

[0147] Example 5:

[0148] The preparation method is the same as that of Example 1, except that:

[0149] Mix 70 parts of PP, 10 parts of HDPE, 10 parts of POE, 10 parts of maleic anhydride grafted PE, 10 parts of modified POSS flame retardant synergist 1, 10 parts of aluminum diethylphosphinate, 0.5 part of lubricant, and 0.5 part of antioxidant evenly, and granulate through a twin-screw extruder at 180 °C to obtain a flame-retardant polypropylene preform. Then, dry it at 80 °C to obtain a high-flame-retardant, crack-resistant, halogen-free flame-retardant polypropylene material.

[0150] Example 6:

[0151] The preparation method is the same as that of Example 1, except that:

[0152] Mix 40 parts of PP, 10 parts of HDPE, 10 parts of POE, 10 parts of maleic anhydride grafted PE, 10 parts of modified POSS flame retardant synergist 1, 10 parts of aluminum diethylphosphinate, 0.5 part of lubricant, and 0.5 part of antioxidant evenly, and granulate through a twin-screw extruder at 180 °C to obtain a flame-retardant polypropylene preform. Then, dry it at 80 °C to obtain a high-flame-retardant, crack-resistant, halogen-free flame-retardant polypropylene material.

[0153] Example 7:

[0154] The preparation method is the same as that of Example 1, except that:

[0155] Mix 70 parts of PP, 10 parts of HDPE, 10 parts of POE, 10 parts of maleic anhydride grafted PE, 12 parts of modified POSS flame retardant synergist 1, 15 parts of aluminum diethylphosphinate, 0.5 part of lubricant, and 0.5 part of antioxidant evenly, and granulate through a twin-screw extruder at 180 °C to obtain a flame-retardant polypropylene preform. Then, dry it at 80 °C to obtain a high-flame-retardant, crack-resistant, halogen-free flame-retardant polypropylene material.

[0156] Example 8:

[0157] Dissolve 2 mol of aminopropyl heptaisobutylcage polyhedral oligomeric silsesquioxane in 100 ml of tetrahydrofuran solution. Add 0.2 mol of acetic acid catalyst to the solution, and add 1 mol of dibenzofuran-3-boronic acid under stirring. Stir and react for 2 - 4 h, stop the reaction, rotary evaporate under reduced pressure, wash with water, and dry to obtain modified POSS flame retardant synergist 2.

[0158] Mix 70 parts of PP, 10 parts of HDPE, 10 parts of POE, 10 parts of maleic anhydride grafted PE, 12 parts of modified POSS flame retardant synergist 2, 5 parts of aluminum diethylphosphinate, 0.5 part of lubricant, and 0.5 part of antioxidant evenly, and granulate through a twin-screw extruder at 180 °C to obtain a flame-retardant polypropylene preform. Then, dry it at 80 °C to obtain a high-flame-retardant, crack-resistant, halogen-free flame-retardant polypropylene material.

[0159] Comparative Example 1:

[0160] The preparation method is the same as that of Example 1, except that:

[0161] Mix 70 parts of PP, 10 parts of HDPE, 10 parts of POE, 10 parts of maleic anhydride grafted PE, 17 parts of modified POSS flame retardant synergist 1, 10 parts of aluminum diethylphosphinate, 0.5 part of lubricant, and 0.5 part of antioxidant evenly, and granulate through a twin-screw extruder at 180 °C to obtain a flame-retardant polypropylene preform. Then, dry it at 80 °C to obtain a high-flame-retardant, crack-resistant, halogen-free flame-retardant polypropylene material.

[0162] Comparative Example 2:

[0163] Mix 70 parts of PP, 10 parts of HDPE, 10 parts of POE, 10 parts of maleic anhydride grafted PE, 27 parts of aluminum diethylphosphinate, 0.5 part of lubricant, and 0.5 part of antioxidant evenly, and granulate through a twin-screw extruder at 180 °C to obtain a flame-retardant polypropylene preform. Then, dry it at 80 °C to obtain a high-flame-retardant, crack-resistant, halogen-free flame-retardant polypropylene material.

[0164] Comparative Example 3:

[0165] The preparation method is the same as that of Example 1, except that:

[0166] Mix 70 parts of PP, 10 parts of HDPE, 10 parts of POE, 10 parts of maleic anhydride grafted PE, 27 parts of modified POSS flame retardant synergist 1, 0.5 part of lubricant, and 0.5 part of antioxidant evenly, and granulate through a twin-screw extruder at 180 °C to obtain a flame-retardant polypropylene preform, and then dry at 80 °C to obtain a high-flame-retardant, crack-resistant, halogen-free flame-retardant polypropylene material.

[0167] Comparative Example 4:

[0168] Mix 70 parts of PP, 10 parts of HDPE, 10 parts of POE, 10 parts of maleic anhydride grafted PE, 12 parts of benzob[b]naphtho[2,3-d]furan-2-hydroxyboric acid flame retardant, 15 parts of aluminum diethylphosphinate, 0.5 part of lubricant, and 0.5 part of antioxidant evenly, and granulate through a twin-screw extruder at 180 °C to obtain a flame-retardant polypropylene preform, and then dry at 80 °C to obtain a high-flame-retardant, crack-resistant, halogen-free flame-retardant polypropylene material.

[0169] Comparative Example 5:

[0170] Mix 70 parts of PP, 10 parts of HDPE, 10 parts of POE, 10 parts of maleic anhydride grafted PE, 12 parts of aminopropyl heptaisobutylcage polyhedral oligomeric silsesquioxane flame retardant, 15 parts of aluminum diethylphosphinate, 0.5 part of lubricant, and 0.5 part of antioxidant evenly, and granulate through a twin-screw extruder at 180 °C to obtain a flame-retardant polypropylene preform, and then dry at 80 °C to obtain a high-flame-retardant, crack-resistant, halogen-free flame-retardant polypropylene material.

[0171] Comparative Example 6:

[0172] Mix 70 parts of PP, 10 parts of HDPE, 10 parts of POE, 10 parts of maleic anhydride grafted PE, 6 parts of benzob[b]naphtho[2,3-d]furan-2-hydroxyboric acid flame retardant, 6 parts of aminopropyl heptaisobutylcage polyhedral oligomeric silsesquioxane flame retardant, 15 parts of aluminum diethylphosphinate, 0.5 part of lubricant, and 0.5 part of antioxidant evenly, and granulate through a twin-screw extruder at 180 °C to obtain a flame-retardant polypropylene preform, and then dry at 80 °C to obtain a high-flame-retardant, crack-resistant, halogen-free flame-retardant polypropylene material.

[0173] Comparative Example 7:

[0174] Dissolve 2 mol of aminopropyl heptaisobutylcage polyhedral oligomeric silsesquioxane in 100 ml of tetrahydrofuran solution, add 0.2 mol of acetic acid catalyst to the solution, and add 1 mol of methylboronic acid under stirring. Stir and react for 2 - 4 h, stop the reaction, rotary evaporate under reduced pressure, wash with water, and dry to obtain a methylboronic acid modified POSS flame retardant.

[0175] Mix 70 parts of PP, 10 parts of HDPE, 10 parts of POE, 10 parts of maleic anhydride grafted PE, 12 parts of methylboronic acid modified POSS flame retardant, 15 parts of aluminum diethylphosphinate, 0.5 part of lubricant, and 0.5 part of antioxidant evenly, and granulate through a twin-screw extruder at 180 °C to obtain a flame-retardant polypropylene preform, and then dry at 80 °C to obtain a high-flame-retardant, crack-resistant, halogen-free flame-retardant polypropylene material.

[0176] Comparative Example 8:

[0177] Dissolve 2 mol of aminopropyl heptaisobutylcage polyhedral oligomeric silsesquioxane in 100 ml of tetrahydrofuran solution, add 0.2 mol of acetic acid catalyst to the solution, and add 1 mol of phenylboronic acid under stirring. Stir and react for 2 - 4 h, stop the reaction, rotary evaporate under reduced pressure, wash with water, and dry to obtain phenylboronic acid modified POSS flame retardant.

[0178] Mix 70 parts of PP, 10 parts of HDPE, 10 parts of POE, 10 parts of maleic anhydride grafted PE, 12 parts of phenylboronic acid modified POSS flame retardant, 15 parts of aluminum diethylphosphinate, 0.5 part of lubricant, and 0.5 part of antioxidant evenly, and granulate through a twin-screw extruder at 180 °C to obtain a flame-retardant polypropylene preform, and then dry at 80 °C to obtain a high-flame-retardant, crack-resistant, halogen-free flame-retardant polypropylene material.

[0179] Summarize the components and important preparation variables of Examples 1 - 8 and Comparative Examples 1 - 8 into Table 2. Table 2 Component table of Examples 1 - 8 and Comparative Examples 1 - 8 of the present invention.

[0180] Table 2 Formulations of Examples and Comparative Examples of the Present Invention

[0181]

[0182] Test according to the provisions of GB / T 1040 - 2008, GB / T 5455, GB / T 2406.2, GB / T 32129, UL94 and GB / T 1409, and test the tensile strength, elongation at break, flame retardant grade, oxygen index, 110 °C thermal shock, 130 °C thermal shock, 150 °C thermal shock, whether it drips during combustion and dielectric constant of the halogen-free flame-retardant polypropylene materials in the above Examples 1 - 8 and Comparative Examples 1 - 8, and record the test results in Table 3 below:

[0183] Table 3 Performance Test Table of Examples 1 - 8 and Comparative Examples 1 - 8 of the Present Invention

[0184]

[0185] As can be seen from Table 3, the flame retardant polypropylene injection-molded sheets of Examples 1-2 and Examples 4-8 have high flame retardant properties, and their flame retardant grades all reach V0 level. During the V0 level test, there is no dripping, and the oxygen index is all >25. Compared with Example 3, a larger amount of the modified POSS flame retardant synergist is added in Example 1. It can be seen that when the content of the modified POSS flame retardant synergist increases, the mechanical properties of the flame retardant polypropylene injection-molded sheet can be further improved, including the tensile strength, elongation at break, and thermal shock performance. Compared with Example 8, the amount of the modified polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist in Comparative Example 1 is too high. The elongation at break of the prepared flame retardant polypropylene material is 155%, which will reduce the physical and mechanical properties of the system, resulting in poor plastic deformation ability of the prepared material and easy brittle fracture. From Examples 8 and Comparative Examples 2 and 3, it can be seen that the modified polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist have a synergistic flame retardant effect with the P-based flame retardant, which can further improve the flame retardant performance and anti-dripping performance of the flame retardant polypropylene injection-molded sheet. From Examples 8 and Comparative Example 4, it can be seen that the polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist have better anti-dripping performance compared with the benz[B]naphtho[2,3-D]furan-2-ylboronic acid flame retardant. From Examples 8 and Comparative Example 9, it can be seen that the polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist have more excellent flame retardant performance and anti-dripping performance compared with the aminopropyl heptaisobutylcaged polyhedral oligomeric silsesquioxane flame retardant. From Examples 8 and Comparative Example 5, it can be seen that the polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist have better anti-dripping performance compared with the flame retardant mixture of aminopropyl heptaisobutylcaged polyhedral oligomeric silsesquioxane and benz[B]naphtho[2,3-D]furan-2-ylboronic acid. From Examples 8 and Comparative Examples 7 and 8, it can be seen that the polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist of the present invention have more excellent flame retardant performance and anti-dripping performance compared with other polyhedral oligomeric silsesquioxane flame retardants modified with boric acid and containing no benzofuran group, polycyclic aromatic group, etc. Thus, it shows that the polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist of the present invention have excellent flame retardant performance and anti-dripping performance.

[0186] Therefore, the present invention verifies that the flame retardancy of the flame retardant polypropylene material is improved by the modified POSS flame retardant synergist, making it have excellent physical and mechanical properties and excellent combustion anti-dripping effect, and has extremely high industrial value, and can be widely applied and promoted.

[0187] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the patent protection scope of the present invention.

Claims

1. A flame retardant polypropylene material, characterized in that: The raw materials of the flame retardant polypropylene material include, by weight: PP40-70 parts, HDPE 10-22 parts, Toughener 10-20 parts, Compatibilizer 10-20 parts, P series flame retardant 10-20 parts, 2-15 parts of modified polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist, Wherein, the structure of the modified polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist is: Wherein, R is a non-reactive group, such as isobutyl, isooctyl, ethyl, cyclohexyl, cyclopentyl, or phenyl, and R1 is n-propyl or phenylene; R2 is a cyclic structure with a carbon-to-hydrogen ratio greater than 1, including at least one of a benzofuran group and a polycyclic aromatic group.

2. The flame retardant polypropylene material according to claim 1, characterized in that: The benzofuran group includes at least one of a benzofuran group and a dibenzofuran group; And / or, the polycyclic aromatic group includes at least one of a naphthalene ring group, an anthracene ring group, a phenanthrene ring group, an acenaphthene ring group, a fluorene ring group and a perylene ring group.

3. The flame retardant polypropylene material according to claim 1, characterized in that: The modified polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist is prepared by dehydration reaction of compound 1 and compound 2 under the action of a catalyst, and the reaction route is as follows:

4. The flame retardant polypropylene material according to claim 3, characterized in that: The molar ratio of compound 1 to compound 2 is 2:

1.

5. The flame retardant polypropylene material according to claim 3, characterized in that: The preparation method of the modified polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist comprises the following steps: Dissolving compound 1 in an organic solvent, adding an aqueous solution of compound 2 under the action of a catalyst, performing a catalytic reaction, and then washing and drying to obtain the modified polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist; Wherein, the organic solvent includes at least one of alcohols, aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons, ethers, ketones and diol derivatives; The catalyst includes at least one of an acidic catalyst, a metal catalyst, and a basic catalyst.

6. The flame retardant polypropylene material according to claim 1, characterized in that: The raw materials of the flame retardant polypropylene material include, by weight: PP40-70 parts, HDPE 10-20 parts, Toughener 10-15 parts, Compatibilizer 10-15 parts, P series flame retardant 10-15 parts, 2-15 parts of modified polyhedral oligomeric silsesquioxane and its derivative flame retardant synergist.

7. The flame retardant polypropylene material according to claim 1, characterized in that: The toughening agent includes at least one of ethylene-octene copolymer, ethylene-propylene copolymer, EMA and EBA.

8. The flame retardant polypropylene material according to claim 1, characterized in that: The compatibilizer includes at least one of PE grafted maleic anhydride, POE grafted maleic anhydride, PP grafted maleic anhydride, and EMA grafted maleic anhydride.

9. The flame retardant polypropylene material according to claim 1, characterized in that: The P series flame retardant includes an inorganic phosphorus flame retardant or an organic phosphorus flame retardant. The inorganic phosphorus flame retardant includes at least one of red phosphorus, phosphate, and polyphosphate; the organic phosphorus flame retardant includes at least one of phosphate, phosphite, and phosphine oxide.

10. The flame retardant polypropylene material according to claim 1, characterized in that: The raw materials of the flame retardant polypropylene material also include at least one of a lubricant and an antioxidant; wherein, in parts by weight, the lubricant is 0.2-1 parts, and the antioxidant is 0.5-2 parts.

11. A method for preparing the flame retardant polypropylene material according to claim 1, characterized in that: The method comprises the following steps: mixing the raw materials uniformly, extruding and granulating through an extruder, and obtaining granular materials, namely the flame-retardant polypropylene material.

12. The method for preparing a flame retardant polypropylene material according to claim 11, characterized in that: The raw material also includes at least one of a lubricant and an antioxidant.

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