Halogen-free high-flame-retardant nylon composite material and preparation method thereof

Abstract

The invention discloses a halogen-free high-flame-retardant nylon composite material and a preparation method thereof. The nylon composite material comprises the following raw materials in parts by mass: 30-50 parts of PA66, 30-50 parts of glass fiber, 0.4-1 part of a silane coupling agent and 4.6-5.9 parts of a composite flame retardant, and the composite flame retardant is a mixture obtained by catalytic reaction of phosphate and octamethylcyclotetrasiloxane; the composite flame retardant is not easy to migrate and separate out from nylon through the interlacing of a long silica chain and a nylon polymer chain and the intermolecular acting force of a silica group and hydrogen on a nylon amide group, the durability of the flame retardant property of the nylon material in a high-temperature and high-humidity environment is prolonged, the composite flame retardant can be mixed and dispersed in the nylon more uniformly, and the flame retardant property of the nylon material is improved. The flame retardant property of the nylon material is improved; therefore, the halogen-free high-flame-retardant nylon composite material disclosed by the invention has excellent flame retardance and still keeps good flame retardance in a high-temperature and high-humidity environment for a long time.

Description

Technical Field

[0001] The present application relates to nylon parts, and in particular to a halogen-free and highly flame-retardant nylon composite material and a preparation method thereof. Background Art

[0002] As a high-performance engineering plastic, nylon is highly favored for its excellent mechanical properties, heat resistance and flame retardancy. With the continuous expansion of application fields and the continuous improvement of technical requirements, the performance of halogen-free flame retardant nylon in specific environments has gradually become a research focus.

[0003] In order to ensure that nylon maintains stable flame retardant properties under various environmental conditions, existing technical means mainly use flame retardants and additives to improve the performance of the material, such as phosphate flame retardants, polyphosphazene flame retardants, zinc borate synergistic flame retardants, etc.

[0004] Although the above method improves the flame retardant properties of nylon materials to a certain extent, these flame retardants and additives have the problem of flame retardant precipitation under high temperature and high humidity environments. Specifically, flame retardants and additives may decompose or migrate under high temperature and high humidity conditions, resulting in a decrease in the flame retardant properties of the material, which cannot meet the requirements of practical applications.

[0005] Therefore, how to develop a halogen-free flame-retardant nylon composite material that can maintain good flame retardant properties under high temperature and high humidity environments is a technical problem that needs to be solved urgently. Summary of the invention

[0006] In order to make nylon parts have long-term excellent flame retardant properties in high temperature and high humidity environments, a halogen-free highly flame-retardant nylon composite material and a preparation method thereof are provided.

[0007] The above first invention objective of the present invention is achieved through the following technical solutions: A halogen-free highly flame-retardant nylon composite material comprises the following raw materials in parts by weight: PA66 30~50 parts, 30-50 parts of glass fiber, Silane coupling agent 0.4-1 part, Composite flame retardant 4.6-5.9 parts, The composite flame retardant is a mixture obtained by catalytic reaction of phosphate ester and octamethylcyclotetrasiloxane.

[0008] By adopting the above technical scheme, the composite flame retardant of the present application is obtained by reacting phosphate ester with octamethylcyclotetrasiloxane, and the octamethylcyclotetrasiloxane is ring-opened under catalysis and reacts with an ester group of the phosphate ester, so that the octamethylcyclotetrasiloxane is ring-opened and connected to the phosphate ester; the composite flame retardant is not easy to migrate and precipitate from the nylon through the long siloxane chain and the intermolecular force between the siloxane group and the hydrogen on the amide group of the nylon, thereby extending the durability of the flame retardant performance of the nylon material in a high temperature and high humidity environment, and can also make the composite flame retardant more uniformly mixed and dispersed in the nylon, thereby improving the flame retardant performance of the nylon material; Therefore, the halogen-free and highly flame-retardant nylon composite material of the present application has excellent flame retardancy and can maintain good flame retardancy for a long time in a high temperature and high humidity environment.

[0009] Optionally: the phosphate ester is triphenyl phosphate.

[0010] By adopting the above technical scheme, the composite flame retardant has better water resistance and still has good stability when the composite flame retardant contacts water brought by nylon moisture absorption. The obtained halogen-free and highly flame-retardant nylon composite material maintains better flame retardancy in a long-term high temperature and high humidity environment.

[0011] Optionally, 0.5 to 1.1 parts of diethyl aluminum hypophosphite are also included.

[0012] By adopting the above technical scheme, diethyl aluminum hypophosphite has good water resistance, can supplement the flame retardant properties of halogen-free and highly flame-retardant nylon composite materials, and inhibit the migration of composite flame retardants in high temperature and high humidity environments.

[0013] Optional: also includes 0.2-0.4 parts of ammonium polyphosphate.

[0014] By adopting the above technical scheme, ammonium polyphosphate reacts with water slowly when the nylon material absorbs moisture to form a new polymer. The new polymer is weakly acidic and combines with the residual siloxane group in the composite flame retardant to strengthen the interweaving of polymer chains in the nylon material, hindering the outward migration and hydrolysis of the composite flame retardant in contact with the hygroscopic water, thereby reducing the precipitation of additives and long-term flame retardant properties of halogen-free and highly flame-retardant nylon composite materials in high temperature and high humidity environments.

[0015] Optionally, the silane coupling agent is 3-glycidyloxypropyltriethoxysilane.

[0016] By adopting the above technical scheme, the glass fiber is modified with 3-glycidyloxypropyltriethoxysilane and has an epoxy group on the surface, which can combine with the amide group NH on the nylon polymer chain, thereby enhancing the compatibility of the glass fiber and nylon and the waterproof and impermeability of the interface between the glass fiber and nylon, thereby reducing the migration of additives in the halogen-free and highly flame-retardant nylon composite material in a high temperature and high humidity environment, and improving the long-term flame retardant performance of the halogen-free and highly flame-retardant nylon composite material in a high temperature and high humidity environment.

[0017] Optionally, the invention further comprises 4.6 to 5.9 parts of an organic composite montmorillonite modifier, wherein the organic composite montmorillonite modifier is obtained by emulsion polymerization of nano-montmorillonite and acrylic acid ester monomer in an aqueous phase.

[0018] By adopting the above technical solution, the nano-montmorillonite presents a flaky multilayer structure, which will adsorb hydrated cations in the water phase to increase the interlayer distance. In the water phase, the nano-montmorillonite is emulsion polymerized with acrylate monomers, and the polymerized acrylate can enter the interlayer distance to form an intercalated polymer. After the organic composite montmorillonite modifier is blended and extruded with nylon, the nano-montmorillonite with intercalated polymer is evenly dispersed in the nylon material, and the hydroxyl groups on the surface of the nano-montmorillonite and the matrix on the intercalated polymer stabilize the distribution of the surrounding composite flame retardant and hinder the migration of the composite flame retardant. Water molecules can pass through the interlayer spacing of nano-montmorillonite and the intercalated polymers formed by the intercalated polymers, but the additives will be blocked and retained, playing a selective blocking role, significantly inhibiting the initiation effect of the dynamic balance of nylon moisture absorption and dehydration under high temperature and high humidity on the migration of additives; This significantly improves the resistance to additive migration and long-lasting flame retardancy of halogen-free and highly flame-retardant nylon composite materials in high temperature and high humidity environments.

[0019] Optionally, the nano-montmorillonite is modified with 3-glycidyloxypropyltrimethoxysilane.

[0020] By adopting the above technical solution, the compatibility of nano-montmorillonite and polyacrylate is improved. During the preparation of the organic composite montmorillonite modifier, the amount of polyacrylate polymerization can smoothly enter the nano-montmorillonite interlayer spacing, thereby improving the anti-additive precipitation effect of the organic composite montmorillonite modifier.

[0021] The above second invention objective of the present invention is achieved through the following technical solutions: The method for preparing the above-mentioned halogen-free highly flame-retardant nylon composite material comprises the following steps: The PA66 resin is placed in a drying oven to remove water and obtain dried nylon; The silane coupling agent, glass fiber and dried nylon are mixed evenly, and then other raw materials are added and mixed evenly to obtain a mixed raw material; the mixed raw material is added into an extruder and extruded to obtain a halogen-free and highly flame-retardant nylon composite material.

[0022] By adopting the above technical scheme, the PA66 resin is dried in advance and the water content of the PA66 resin is reduced, which is beneficial to the uniform mixing of raw materials in the halogen-free and highly flame-retardant nylon composite material, and the cross-linking between nylon polymer chains is tighter, so that the halogen-free and highly flame-retardant nylon composite material has better performance.

[0023] In summary, this application has at least the following beneficial effects: The composite flame retardant of the present application is obtained by the reaction of phosphate ester and octamethylcyclotetrasiloxane. The octamethylcyclotetrasiloxane is ring-opened under the catalysis and reacts with an ester group of the phosphate ester, so that the octamethylcyclotetrasiloxane is ring-opened and connected to the phosphate ester; the composite flame retardant is not easy to migrate and precipitate from the nylon through the interweaving of the nylon polymer chain by the long siloxy chain and the intermolecular force between the siloxy group and the hydrogen on the amide group of the nylon, thereby extending the durability of the flame retardant performance of the nylon material in a high temperature and high humidity environment, and can also make the composite flame retardant more uniformly mixed and dispersed in the nylon, thereby improving the flame retardant performance of the nylon material; thereby, the halogen-free and highly flame-retardant nylon composite material of the present application has excellent flame retardancy, and still maintains good flame retardancy for a long time in a high temperature and high humidity environment. DETAILED DESCRIPTION

[0024] raw material Nano-montmorillonite is a commercially available product in the form of multi-layer flakes with a thickness of 7±1 nm and an equivalent particle size of 100 nm.

[0025] Polyoxyethylene stearate is a commercially available product, and has a saponification value of 72 mgKOH / g.

[0026] PA66 resin is POM American DuPont 100AL NC010 product.

[0027] The glass fiber is an alkali-free glass fiber with a length of 3 mm and a diameter of 10 μm.

[0028] The acrylate monomer is ethyl acrylate, a commercially available product.

[0029] Tetrahydrofuran, benzoyl peroxide, ethanol, and 3-glycidyloxypropyltrimethoxysilane are commercially available products with a purity greater than 99.5wt%. Ammonium polyphosphate, phenyltrimethoxysilane, n-octyltriethoxysilane, triphenyl phosphate, dimethyl methyl phosphate, octamethylcyclotetrasiloxane, and diethylaluminum hypophosphite are commercially available products with a purity greater than 99 wt%. Preparation Example 1 The organic composite montmorillonite modifier has the following preparation method: The nano-montmorillonite and tetrahydrofuran are mixed in a mass ratio of 1:10, and ultrasonic vibration is used to mix the mixture to obtain a nano-montmorillonite suspension after the mixture is evenly mixed. Add 3-glycidyloxypropyltrimethoxysilane to the nano-montmorillonite suspension, wherein the amount of 3-glycidyloxypropyltrimethoxysilane added is 1.2 times the mass of the nano-montmorillonite, stir and mix for 5 minutes, and then centrifuge and dry to obtain modified montmorillonite; The modified nano-montmorillonite, water, acrylate monomer, polyoxyethylene stearate and benzoyl peroxide were mixed and stirred uniformly in a mass ratio of 30:190:200:4:0.8, and then emulsion polymerization was carried out in an inert gas atmosphere at a temperature of 80°C; When the emulsion polymerization conversion rate reaches 95%, ethanol (the amount of ethanol added is 10wt% of the amount of acrylate monomer) is added for demulsification treatment, and after washing, vacuum drying is carried out at 80°C for 12h to obtain an organic composite montmorillonite modifier.

[0030] Preparation Example 2 The organic composite montmorillonite modifier has the following preparation method: Nano-montmorillonite, water, acrylate monomer, polyoxyethylene stearate and benzoyl peroxide were mixed and stirred in a mass ratio of 30:190:200:4:0.8, and then emulsion polymerization was carried out in an inert gas atmosphere at a temperature of 80°C; When the emulsion polymerization conversion rate reaches 95%, ethanol (the amount of ethanol added is 10wt% of the amount of acrylate monomer) is added for demulsification treatment, and after washing, vacuum drying is carried out at 80°C for 12h to obtain an organic composite montmorillonite modifier.

[0031] Preparation Example 3 A composite flame retardant, the preparation method of which is as follows: 3.26 kg of triphenyl phosphate, 2.96 kg of octamethylcyclotetrasiloxane and 0.002 kg of p-toluenesulfonic acid were mixed and reacted at 56° C. for 8 hours to obtain a composite flame retardant.

[0032] The molar ratio of triphenyl phosphate to octamethylcyclotetrasiloxane is 1:1.

[0033] Preparation Example 4 A composite flame retardant, the preparation method of which is as follows: 1.24 kg of dimethyl methyl phosphate, 2.96 kg of octamethylcyclotetrasiloxane, and 0.002 kg of p-toluenesulfonic acid were mixed and reacted at 56° C. for 8 hours to obtain a composite flame retardant.

[0034] The molar ratio of dimethyl methyl phosphate to octamethylcyclotetrasiloxane is 1:1.

[0035] Example 1 A halogen-free highly flame-retardant nylon composite material, whose raw materials are PA66, glass fiber, composite flame retardant, silane coupling agent, diethyl aluminum hypophosphite and ammonium polyphosphate.

[0036] The specific preparation method is as follows: 42 kg of PA66 resin was placed in an oven and baked at 80° C. for 4 hours to remove water absorbed during storage to obtain dried nylon; 0.76 kg of silane coupling agent, 42 kg of glass fiber, and dried nylon were weighed and mixed evenly, and then 5.3 kg of composite flame retardant, 0.8 kg of diethyl aluminum hypophosphite, and 0.3 kg of ammonium polyphosphate were added and mixed evenly to obtain a mixed raw material; The mixed raw materials were added into the extruder, and the process parameters of the extruder were 235°C in the first zone, 265°C in the second zone, 255°C in the third zone, 245°C in the fourth zone, 235°C in the fifth zone, 225°C in the sixth zone, 215°C in the seventh zone, 190°C in the eighth zone, 180°C in the ninth zone, and 250°C in the die.

[0037] The main engine speed is 480r / min, the feeding speed is 10kg / min, and the vacuum degree is 0.08MPa.

[0038] The composite flame retardant is prepared in Preparation Example 3.

[0039] The silane coupling agent is phenyltrimethoxysilane.

[0040] The organic composite montmorillonite modifier is prepared in Preparation Example 1.

[0041] Example 2 A halogen-free highly flame-retardant nylon composite material, whose raw materials are PA66, glass fiber, composite flame retardant, silane coupling agent, diethyl aluminum hypophosphite, ammonium polyphosphate and organic composite montmorillonite modifier.

[0042] The specific preparation method is as follows: 42 kg of PA66 resin was placed in an oven and baked at 80° C. for 4 hours to remove water absorbed during storage to obtain dried nylon; 0.76 kg of silane coupling agent, 42 kg of glass fiber, and dried nylon were weighed and mixed evenly, and then 5.3 kg of composite flame retardant, 0.8 kg of diethyl aluminum hypophosphite, 0.3 kg of ammonium polyphosphate, and 5.1 kg of organic composite montmorillonite modifier were added and mixed evenly to obtain a mixed raw material; The mixed raw materials were added into the extruder, and the process parameters of the extruder were 235°C in the first zone, 265°C in the second zone, 255°C in the third zone, 245°C in the fourth zone, 235°C in the fifth zone, 225°C in the sixth zone, 215°C in the seventh zone, 190°C in the eighth zone, 180°C in the ninth zone, and 250°C in the die.

[0043] The main engine speed is 480r / min, the feeding speed is 10kg / min, and the vacuum degree is 0.08MPa.

[0044] The composite flame retardant is prepared in Preparation Example 3.

[0045] The silane coupling agent is phenyltrimethoxysilane.

[0046] The organic composite montmorillonite modifier is prepared in Preparation Example 1.

[0047] Example 3 A halogen-free and highly flame-retardant nylon composite material, which differs from Example 2 in that the composite flame retardant is prepared according to Preparation Example 4.

[0048] Example 4 A halogen-free highly flame-retardant nylon composite material, which differs from Example 2 in that the amount of ammonium polyphosphate used is 0, that is, no ammonium polyphosphate is added to the raw materials.

[0049] Example 5 A halogen-free highly flame-retardant nylon composite material, which is different from Example 2 in that the amount of diethyl aluminum hypophosphite is 0, that is, diethyl aluminum hypophosphite is not added to the raw materials.

[0050] Example 6 A halogen-free highly flame-retardant nylon composite material, which differs from Example 2 in that the silane coupling agent is n-octyltriethoxysilane.

[0051] Example 7 A halogen-free highly flame-retardant nylon composite material is different from Example 2 in that the organic composite montmorillonite modifier is prepared as Preparation Example 2.

[0052] Example 8 A halogen-free highly flame-retardant nylon composite material, which differs from Example 2 in the amount of raw materials used, specifically: 30kg PA66 resin, 30kg glass fiber, 5kg phosphate flame retardant, 0.4kg silane coupling agent, 7kg octamethylcyclotetrasiloxane, 0.5kg diethyl aluminum hypophosphite, 0.2kg ammonium polyphosphate, and 4.6kg organic composite montmorillonite modifier.

[0053] Example 9 A halogen-free highly flame-retardant nylon composite material, which differs from Example 2 in the amount of raw materials used, specifically: 50kg PA66 resin, 50kg glass fiber, 7.6kg phosphate flame retardant, 1kg silane coupling agent, 8kg octamethylcyclotetrasiloxane, 1.1kg diethyl aluminum hypophosphite, 0.4kg ammonium polyphosphate, and 5.9kg organic composite montmorillonite modifier.

[0054] Comparative Example 1 A halogen-free highly flame-retardant nylon composite material, whose raw materials are PA66, glass fiber, phosphate flame retardant, silane coupling agent, diethyl aluminum hypophosphite and ammonium polyphosphate.

[0055] The specific preparation method is as follows: 42 kg of PA66 resin was placed in an oven and baked at 80° C. for 4 hours to remove water absorbed during storage to obtain dried nylon; 0.76 kg of silane coupling agent, 42 kg of glass fiber, and dried nylon were weighed and mixed evenly, and then 2.78 kg of triphenyl phosphate, 0.8 kg of diethyl aluminum hypophosphite, and 0.3 kg of ammonium polyphosphate were added and mixed evenly to obtain a mixed raw material; The mixed raw materials were added into the extruder, and the process parameters of the extruder were 235°C in the first zone, 265°C in the second zone, 255°C in the third zone, 245°C in the fourth zone, 235°C in the fifth zone, 225°C in the sixth zone, 215°C in the seventh zone, 190°C in the eighth zone, 180°C in the ninth zone, and 250°C in the die.

[0056] The main engine speed is 480r / min, the feeding speed is 10kg / min, and the vacuum degree is 0.08MPa.

[0057] The silane coupling agent is phenyltrimethoxysilane.

[0058] The organic composite montmorillonite modifier is prepared in Preparation Example 1.

[0059] Comparative Example 2 A halogen-free highly flame-retardant nylon composite material, whose raw materials are PA66, glass fiber, phosphate flame retardant, octamethylcyclotetrasiloxane, silane coupling agent, diethyl aluminum hypophosphite and ammonium polyphosphate.

[0060] The specific preparation method is as follows: 42kg PA66 resin was placed in an oven and baked at 80°C for 4h to remove water absorbed during storage to obtain dried nylon; 0.76kg silane coupling agent, 42kg glass fiber, and dried nylon were weighed and mixed evenly, and then 2.78kg triphenyl phosphate, 2.52kg octamethylcyclotetrasiloxane, 0.8kg diethyl aluminum hypophosphite, and 0.3kg ammonium polyphosphate were added and mixed evenly to obtain a mixed raw material; the mixed raw material was added to an extruder, and the process parameters of the extruder were 235°C in the first zone, 265°C in the second zone, 255°C in the third zone, 245°C in the fourth zone, 235°C in the fifth zone, 225°C in the sixth zone, 215°C in the seventh zone, 190°C in the eighth zone, 180°C in the ninth zone, and 250°C in the die head.

[0061] The main engine speed is 480r / min, the feeding speed is 10kg / min, and the vacuum degree is 0.08MPa.

[0062] The silane coupling agent is phenyltrimethoxysilane.

[0063] The flame retardant properties of the nylon materials of Examples 1 to 9 and the nylon materials obtained in Comparative Examples 1 to 2 were tested, the precipitation of double 85 was tested, and the flame retardant properties after the simulation of the precipitation of double 85 were tested.

[0064] Flame retardant performance test: tested according to ASTMD 618 standard with UL 94 grade, sample thickness is 0.8mm, and the result is expressed as flame retardant grade.

[0065] Double 85 precipitation test: The sample with a thickness of 0.8mm is stored at a temperature of 85℃ and a relative humidity of 85%, and the precipitation of additives on the sample surface is observed. The result is expressed as the precipitation time of the additive.

[0066] Flame retardant performance test after double 85 precipitation simulation: The flame retardant performance of the sample with a thickness of 0.8mm was tested at a temperature of 85℃ and a relative humidity of 85% for 50 days and 80 days respectively. The flame retardant performance test was carried out according to the ASTMD 618 standard with UL 94 grade. The sample thickness was 0.8mm and the result was expressed as flame retardant grade.

[0067] The test results are shown in Table 1 below.

[0068] Combined with Table 1, it can be seen that, by comparing Example 1 with Comparative Examples 1 to 2, the flame retardant performance of Example 1 is better than that of Comparative Examples 1 to 2, the precipitation resistance of the additive of Example 1 in the double 85 precipitation test results is significantly better than that of Comparative Examples 1 to 2, and the flame retardant performance of Example 1 after double 85 precipitation simulation is still good and significantly better than that of Comparative Examples 1 to 2.

[0069] The composite flame retardant in the present application is obtained by the reaction of phosphate ester and octamethylcyclotetrasiloxane. The octamethylcyclotetrasiloxane is ring-opened under the catalysis and reacts with an ester group of the phosphate ester, so that the octamethylcyclotetrasiloxane is ring-opened and connected to the phosphate ester; the composite flame retardant is interwoven with the nylon polymer chain through the long siloxy chain and the intermolecular force between the siloxy group and the hydrogen on the amide group of the nylon, so that the composite flame retardant is not easy to migrate and precipitate from the nylon, thereby extending the durability of the flame retardant performance of the nylon material in a high temperature and high humidity environment, and can also make the composite flame retardant more uniformly mixed and dispersed in the nylon, thereby improving the flame retardant performance of the nylon material. Therefore, the halogen-free and highly flame-retardant nylon composite material of the present application has excellent flame retardancy and can still maintain good flame retardancy for a long time in a high temperature and high humidity environment.

[0070] Comparing Example 1 and Example 2, Example 2 further adds an organic composite montmorillonite modifier to the raw materials compared with Example 1. In the double 85 precipitation test results of Example 2, the precipitation resistance of the additive of Example 1 is significantly better than that of Example 1, and the flame retardant performance of Example 1 after double 85 precipitation simulation is better than that of Example 1.

[0071] The reason is that the interlayer spacing of the nano-montmorillonite in the organic composite montmorillonite modifier increases during the preparation process, and the polymerized acrylate is introduced into the interlayer spacing to form an intercalated polymer; after the organic composite montmorillonite modifier is blended and extruded with nylon, the nano-montmorillonite with the intercalated polymer is evenly dispersed in the nylon material, and the hydroxyl groups on the surface of the nano-montmorillonite and the matrix on the intercalated polymer stabilize the distribution of the surrounding composite flame retardant and hinder the migration of the composite flame retardant; water molecules can pass through the interlayer spacing of the nano-montmorillonite and the intercalated polymer therein, which are stabilized by the formation of the intercalated polymer, but the additives will be blocked and retained, playing a selective blocking role, significantly inhibiting the initiation effect of the dynamic balance of nylon moisture absorption and dehydration under high temperature and high humidity on the migration of additives; thereby significantly improving the additive migration resistance and long-lasting flame retardancy of the halogen-free and highly flame-retardant nylon composite material in high temperature and high humidity environments.

[0072] Comparing Example 2 and Example 3, the difference between Example 2 and Example 3 is that different phosphates are used in the composite flame retardant. In the double 85 precipitation test results of Example 2, the precipitation resistance of the additive of Example 1 is significantly better than that of Example 3. The flame retardant performance of Example 2 after double 85 precipitation simulation is better than that of Example 3. This is because triphenyl phosphate has better water resistance. The composite flame retardant used in Example 2 has better water resistance than that of Example 3. When the composite flame retardant contacts water brought by nylon moisture absorption, it still has good stability. The obtained halogen-free and highly flame-retardant nylon composite material maintains better flame retardancy under long-term high temperature and high humidity environment.

[0073] By comparing Example 2 and Example 4, it can be seen that in the double 85 precipitation test results of Example 2, the precipitation resistance of the additive of Example 1 is better than that of Example 4, and the flame retardant performance of Example 2 after double 85 precipitation simulation is better than that of Example 4. This is because the ammonium polyphosphate slowly reacts with water to form a new polymer when the nylon material absorbs moisture. The new polymer is weakly acidic and combines with the residual siloxane group in the composite flame retardant to strengthen the interweaving of the polymer chains in the nylon material, hindering the composite flame retardant that contacts with the hygroscopic water from migrating outward and hydrolyzing, thereby reducing the precipitation of additives and the long-term flame retardant performance of the halogen-free and highly flame-retardant nylon composite material in a high temperature and high humidity environment.

[0074] By comparing Example 2 and Example 5, it can be seen that in the double 85 precipitation test results of Example 2, the precipitation resistance of the additive of Example 1 is significantly better than that of Example 5, and the flame retardant performance of Example 2 after double 85 precipitation simulation is better than that of Example 5. This is because diethyl aluminum hypophosphite has good water resistance, can supplement the flame retardant properties of halogen-free and highly flame-retardant nylon composite materials, and inhibit the migration of composite flame retardants in high temperature and high humidity environments.

[0075] By comparing Example 2 and Example 6, it can be seen that in the double 85 precipitation test results of Example 2, the precipitation resistance of the additive of Example 1 is significantly better than that of Example 6, and the flame retardant performance of Example 2 after double 85 precipitation simulation is better than that of Example 6. This is because the glass fiber is modified with 3-glycidyloxypropyltriethoxysilane and has an epoxy group on the surface, which can combine with the amide group NH on the nylon polymer chain, thereby enhancing the compatibility between the glass fiber and nylon and the waterproof and impermeability of the interface between the glass fiber and nylon, thereby reducing the migration of additives of the halogen-free and highly flame-retardant nylon composite material in a high temperature and high humidity environment, and improving the long-term flame retardant performance of the halogen-free and highly flame-retardant nylon composite material in a high temperature and high humidity environment.

[0076] By comparing Example 2 and Example 7, it can be seen that in the double 85 precipitation test results of Example 2, the additive precipitation resistance of Example 1 is significantly better than that of Example 6, and the flame retardant performance of Example 2 after double 85 precipitation simulation is better than that of Example 6. This is because after the nano-montmorillonite is first modified, the compatibility of the nano-montmorillonite and the polyacrylate is improved, and the amount of polyacrylate polymerization in the preparation process of the organic composite montmorillonite modifier can smoothly enter the nano-montmorillonite interlayer spacing, thereby improving the anti-auxiliary agent precipitation effect of the organic composite montmorillonite modifier.

[0077] Combining Comparative Example 2, Examples 8-9, and Comparative Examples 1-2, it can be seen that: The precipitation resistance of double 85 in Examples 8 to 9 is significantly better than that in Comparative Examples 1 to 2, and is similar to that in Example 2; The flame retardant properties of Examples 8 to 9 after simulation of double 85 precipitation are better than those of Comparative Examples 1 to 2, and are similar to those of Example 2; therefore, the mass ratio of raw materials of the halogen-free and highly flame-retardant nylon composite material of the present application is controlled to be PA66: glass fiber: silane coupling agent: composite flame retardant = (30 to 50): (30 to 50): (0.4 to 1): (4.6 to 5.9), and the obtained halogen-free and highly flame-retardant nylon composite material has good resistance to auxiliary agent precipitation under high temperature and high humidity environment and maintains long-lasting flame retardant properties.

[0078] This specific embodiment is only an explanation of the present invention, and it is not a limitation of the present invention. After reading this specification, those skilled in the art can make non-creative modifications to this embodiment as needed, but as long as it is within the scope of protection required by the present invention, it will be protected by the patent law.

Claims

1. A halogen-free highly flame-retardant nylon composite material, characterized in that: Including the following raw materials by mass: PA66 30~50 parts, 30~50 parts of glass fiber, Silane coupling agent 0.4~1 part, Composite flame retardant 4.6~5.9 parts, The composite flame retardant is a mixture obtained by catalytic reaction of phosphate ester and octamethylcyclotetrasiloxane.

2. The halogen-free highly flame-retardant nylon composite material according to claim 1, characterized in that: The phosphate ester is triphenyl phosphate.

3. The halogen-free highly flame-retardant nylon composite material according to claim 1, characterized in that: It also includes 0.5 to 1.1 parts of diethyl aluminum hypophosphite.

4. The halogen-free highly flame-retardant nylon composite material according to claim 3, characterized in that: It also includes 0.2 to 0.4 parts of ammonium polyphosphate.

5. The halogen-free highly flame-retardant nylon composite material according to claim 3, characterized in that: The silane coupling agent is 3-glycidyloxypropyltriethoxysilane.

6. The halogen-free and highly flame-retardant nylon composite material according to claim 1, characterized in that: The invention also comprises 4.6-5.9 parts of an organic composite montmorillonite modifier, wherein the organic composite montmorillonite modifier is obtained by emulsion polymerization of nano-montmorillonite and acrylic ester monomer in water phase.

7. The halogen-free and highly flame-retardant nylon composite material according to claim 1, characterized in that: The nano-montmorillonite is modified by 3-glycidyloxypropyltrimethoxysilane.

8. The method for preparing the halogen-free highly flame-retardant nylon composite material according to any one of claims 1 to 7, characterized in that: The following steps are involved: The PA66 resin is placed in a drying oven to remove water and obtain dried nylon; The silane coupling agent, glass fiber and dried nylon are mixed evenly, and then other raw materials are added and mixed evenly to obtain a mixed raw material; The mixed raw materials are added into an extruder to extrude to obtain a halogen-free and highly flame-retardant nylon composite material.

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