Antibacterial halogen-free flame-retardant polyamide composition and preparation method thereof

Abstract

The invention provides an antibacterial halogen-free flame-retardant polyamide composition and a preparation method thereof. The antibacterial halogen-free flame-retardant polyamide composition comprises polyamide with a phosphorus-containing flame-retardant structure and a non-reactive phosphorus flame retardant, the non-reactive phosphorus flame retardant comprises zinc diethyl hypophosphite; the D95 particle size of the non-reactive phosphorus flame retardant is less than or equal to 1 mu m. The composition of the antibacterial halogen-free flame-retardant polyamide composition is designed, the polyamide composition with good flame retardance and antibacterial property is obtained under the condition that other antibacterial agents do not need to be additionally added, the adverse effect on the polyamide polymerization process caused by the large adding amount of a reactive flame retardant is avoided, and the flame retardance and the antibacterial property of the polyamide composition are improved. Meanwhile, the influence of additional addition of an antibacterial agent on the mechanical property and the spinning property of the flame-retardant polyamide is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of flame-retardant polyamide compositions, and in particular relates to an antibacterial halogen-free flame-retardant polyamide composition and a preparation method thereof. Background Art

[0002] Polyamide 66 (nylon 66), also known as polyhexamethylene adipamide, is a thermoplastic resin, a white translucent solid, and one of the most widely used varieties of engineering plastics. It has excellent wear resistance, self-lubrication and chemical corrosion resistance. However, the limiting oxygen index of polyamide 66 is only 21% to 23%, the dripping phenomenon is serious, and the flame retardant performance is poor, which seriously limits the application of polyamide 66 in various industries. Therefore, improving the flame retardant and anti-drip properties of polyamide 66 has important practical significance.

[0003] The synthesis of polyamide 66 is usually obtained by polycondensation of adipic acid and hexamethylenediamine. The production process mainly includes three steps: monomer synthesis, preparation of polyamide 66 salt and polycondensation. In the production, adipic acid and hexamethylenediamine are mixed to make polyamide 66 salt, and then the polyamide 66 salt is polycondensed at high temperature, accompanied by the removal of water, to generate polyamide 66.

[0004] At present, the schemes for synthesizing nylon 66 are relatively mature, and various functions are given to polyamide 66 through the use of functional additives, such as preparing flame-retardant polyamide 66 through the use of flame retardants, or obtaining polyamide materials with antibacterial properties through the use of antibacterial agents. Among them, the flame retardants suitable for polyamide 66 mainly include halogen, nitrogen, inorganic and phosphorus flame retardants. Different flame retardants vary greatly in flame retardant mechanism, flame retardant efficiency and impact on material properties. Among them, halogen flame retardants are the most widely used, the largest in usage and the best in flame retardant effect. However, halogen flame retardants release a large amount of smoke and toxic gases when burned, which are harmful to the environment and human body. Inorganic flame retardants are widely used in the field of flame retardancy due to their advantages such as good thermal stability, low volatility, low corrosiveness and almost non-toxicity, but usually require a higher addition amount to achieve a better flame retardant effect. Compared with halogen flame retardants and inorganic flame retardants, nitrogen flame retardants have advantages such as good stability and environmental friendliness. However, nitrogen flame retardants are mostly introduced into polyamide in physical form, which has the problems of large addition amount and easy precipitation. Phosphorus flame retardants have the advantages of good thermal stability, low volatility, no corrosive gas generation, long-lasting flame retardancy and low toxicity. They have been widely used in the field of flame-retardant polyamide in recent years, but are currently mainly added to polyamide 66 in the form of physical addition. In this technical solution, the amount of flame retardant added is high, the dispersion is uneven and it is easy to precipitate, which has a great impact on the mechanical properties of polyamide 66. If you want to obtain a polyamide that is both flame retardant and antibacterial, you need to add flame retardants and antibacterial agents at the same time. Both of them are added in high amounts and are easy to precipitate.

[0005] Therefore, how to provide a polyamide that has both flame retardancy and antibacterial properties as well as good mechanical properties has become a technical problem that needs to be solved urgently. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide an antibacterial halogen-free flame-retardant polyamide composition and a preparation method thereof. In the present invention, by designing the composition of the antibacterial halogen-free flame-retardant polyamide composition, a polyamide composition with good flame retardancy and antibacterial properties is obtained without the need to add other antibacterial agents, thereby solving the adverse effects of large amounts of reactive flame retardants on the polyamide polymerization process, and solving the effects of additional antibacterial agents on the mechanical properties and spinning properties of flame-retardant polyamide.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides an antibacterial halogen-free flame-retardant polyamide composition, wherein the antibacterial halogen-free flame-retardant polyamide composition comprises a polyamide containing a phosphorus-based flame-retardant structure and a non-reactive phosphorus-based flame retardant;

[0009] The non-reactive phosphorus-based flame retardant includes diethyl zinc hypophosphite;

[0010] The non-reactive phosphorus-based flame retardant D 95 Particle size ≤1μm.

[0011] In the present invention, the composition of the antibacterial halogen-free flame retardant polyamide composition is designed, and the structure of the polyamide is further designed, and the polyamide containing a phosphorus-based flame retardant structure and a polyamide with a specific D 95 The compounding of a non-reactive phosphorus-based flame retardant (zinc diethyl hypophosphite) with a small particle size can obtain a polyamide composition with good flame retardancy and antibacterial properties without the need to add other antibacterial agents. This solves the adverse effect of large amounts of reactive flame retardants on the polyamide polymerization process, and at the same time solves the effect of additional antibacterial agents on the mechanical properties and spinning properties of flame-retardant polyamide.

[0012] In the present invention, by using nanometer-grade zinc diethyl phosphite, a polyamide composition having good flame retardancy and antibacterial properties is prepared without using an additional antibacterial agent, and the nanometer-grade zinc diethyl phosphite has both antibacterial and flame retardant effects.

[0013] In the present invention, by controlling the D 95 The particle size is ≤1μm, which makes the polyamide composition have excellent comprehensive performance. 95 If the particle size is too large, phenomena such as floating and broken fibers are likely to occur during the spinning process, reducing the spinnability of the product.

[0014] In the present invention, the non-reactive phosphorus-based flame retardant has a D 95 The particle size may be 10 nm, 50 nm, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm or 1 μm, etc.

[0015] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0016] As a preferred technical solution of the present invention, the non-reactive phosphorus-based flame retardant D 95 The particle size is 0.2 μm to 0.8 μm, for example, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm or 0.8 μm.

[0017] In the present invention, by selecting D 95 The non-reactive phosphorus-based flame retardant with a particle size of 0.2 μm to 0.8 μm further optimizes the comprehensive performance of the antibacterial halogen-free flame-retardant polyamide composition.

[0018] As a preferred technical solution of the present invention, the mass percentage of phosphorus in the polyamide with phosphorus-containing flame retardant structure is 0.15%-0.55%, for example, it can be 0.15%, 0.20%, 0.25%, 0.30%, 0.35%, 0.40%, 0.45%, 0.50% or 0.55%, etc.

[0019] Taking the mass percentage of the antibacterial halogen-free flame retardant polyamide composition as 100%, the mass percentage of the non-reactive phosphorus-based flame retardant is 2%-10%, for example, it can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, etc., preferably 3%-5%.

[0020] In the present invention, an antibacterial halogen-free flame retardant polyamide composition with good flame retardancy, antibacterial properties and mechanical properties is prepared by limiting the mass percentage of phosphorus element and the content of non-reactive phosphorus flame retardant in the polyamide containing phosphorus flame retardant structure within a specific range, and using a non-reactive phosphorus flame retardant with a specific particle size.

[0021] As a preferred technology of the present invention, the polyamide containing phosphorus-based flame retardant structure includes a polyamide 66 structure and a phosphorus-based flame retardant structure;

[0022] The raw materials for preparing the phosphorus-based flame retardant structure include reactive phosphorus-based flame retardant and diamine.

[0023] Preferably, the reactive phosphorus-based flame retardant includes a DOPO-based flame retardant and / or a DDP-based flame retardant.

[0024] Preferably, the DOPO-based flame retardant has a structure as shown in the following formula I:

[0025]

[0026] R1 is selected from C1-C15 alkylene, for example, it can be C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14 or C15.

[0027] Preferably, the DDP-based flame retardant has a structure as shown in the following formula II:

[0028]

[0029] R2 is selected from C1-C15 alkylene, for example, it can be C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14 or C15.

[0030] Preferably, the number of carbon atoms of the diamine is C2-C14 (for example, it can be C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13 or C14), and more preferably any one of pentamethylenediamine, hexamethylenediamine, octanediamine, decanediamine or 2-methyloctanediamine, or a combination of at least two thereof.

[0031] In a second aspect, the present invention provides a method for preparing the bacterial halogen-free flame-retardant polyamide composition as described in the first aspect, the preparation method comprising the following steps:

[0032] The antibacterial halogen-free flame-retardant polyamide composition is obtained by mixing a solution containing polyamide 66 salt, a solution containing a reactive phosphorus-based flame retardant salt and a non-reactive phosphorus-based flame retardant, and then performing a polymerization reaction.

[0033] As a preferred technical solution of the present invention, the solution containing the reactive phosphorus-based flame retardant salt is prepared by the following method, which comprises the following steps:

[0034] The reactive phosphorus-based flame retardant, diamine and solvent are mixed and then subjected to a salt-forming reaction to obtain the solution containing the reactive phosphorus-based flame retardant salt.

[0035] Preferably, the molar ratio of the reactive phosphorus-based flame retardant to the diamine is 1:(1.0-1.2), for example, it can be 1:1.0, 1:1.02, 1:1.04, 1:1.06, 1:1.08, 1:1.1, 1:1.12, 1:1.14, 1:1.16, 1:1.18 or 1:1.2, etc.

[0036] Preferably, the mass ratio of the reactive phosphorus-based flame retardant to the solvent is 1:(1.0-2.0), for example, it can be 1:1.0, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 1:2.0, etc.

[0037] Preferably, the solvent comprises water.

[0038] Preferably, the mixing method includes stirring, and the stirring speed is 50rpm-400rpm, for example, it can be 50rpm, 100rpm, 150rpm, 200rpm, 250rpm, 300rpm, 350rpm or 400rpm.

[0039] Preferably, the temperature of the salt-forming reaction is 60°C-90°C (for example, it can be 60°C, 63°C, 66°C, 68°C, 70°C, 72°C, 75°C, 77°C, 78°C, 81°C, 84°C, 86°C, 88°C or 90°C, etc.), and the time is 2h-5h (for example, it can be 2h, 2.5h, 3h, 3.5h, 4h, 4.5h or 5h, etc.).

[0040] In the present invention, there is no special limitation on the preparation method of the solution containing polyamide 66 salt, and all commonly used preparation methods in the art are applicable, including but not limited to:

[0041] The solution containing polyamide 66 salt is prepared by the following method, which comprises the following steps:

[0042] Hexamethylenediamine, adipic acid and water are mixed and neutralized into salt to obtain a solution containing polyamide 66 salt.

[0043] Wherein, the molar ratio of hexamethylenediamine to adipic acid is (1.0-1.3):1, for example, it can be 1.0:1, 1.05:1, 1.1:1, 1.15:1, 1.2:1, 1.25:1 or 1.3:1, etc.

[0044] It should be noted that, in the present invention, there are no special restrictions on the mass concentration of the hexamethylenediamine solution, the mass concentration of the adipic acid solution, the temperature and time for neutralization to form salts, and all commonly used process conditions in the art are applicable.

[0045] It should also be noted that the solution containing polyamide 66 salt can be prepared by oneself and can be purchased.

[0046] As a preferred technical solution of the present invention, the mass concentration of polyamide 66 salt in the solution containing polyamide 66 salt is 50%-60%, for example, it can be 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59% or 60%, etc.

[0047] Preferably, the mass concentration of the reactive phosphorus-based flame retardant salt in the solution containing the reactive phosphorus-based flame retardant salt is 40%-60%, for example, it can be 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58% or 60%, etc.

[0048] Preferably, the raw materials for preparing the antibacterial halogen-free flame-retardant polyamide composition include the following components in parts by weight:

[0049] 90-100 parts of polyamide 66 salt;

[0050] 3 to 10 parts of reactive phosphorus flame retardant salt;

[0051] 3 to 10 parts of non-reactive phosphorus flame retardant.

[0052] In the present invention, by designing the dosage of polyamide 66 salt, reactive phosphorus flame retardant salt and non-reactive phosphorus flame retardant, the antibacterial halogen-free flame retardant polyamide composition is finally prepared, wherein the mass percentage of phosphorus element in the polyamide with phosphorus flame retardant structure is 0.15%-0.55%, and the mass percentage of the non-reactive phosphorus flame retardant is 2%-10% based on the mass percentage of the antibacterial halogen-free flame retardant polyamide composition being 100%.

[0053] In the present invention, the weight parts of polyamide 66 salt in the raw materials for preparing the antibacterial halogen-free flame retardant polyamide composition can be 90 parts, 91 parts, 92 parts, 93 parts, 94 parts, 95 parts, 96 parts, 97 parts, 98 parts, 99 parts or 100 parts.

[0054] The weight proportion of the reactive phosphorus-based flame retardant salt in the raw materials for preparing the antibacterial halogen-free flame retardant polyamide composition may be 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts.

[0055] The weight proportion of the non-reactive phosphorus-based flame retardant in the raw materials for preparing the antibacterial halogen-free flame-retardant polyamide composition can be 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts.

[0056] As a preferred technical solution of the present invention, the polymerization reaction temperature is 275°C-290°C, for example, it can be 275°C, 278°C, 280°C, 282°C, 284°C, 286°C, 288°C or 290°C.

[0057] Preferably, the polymerization reaction time is 2 h-4 h, for example, 2 h, 2.5 h, 3 h, 3.5 h or 4 h.

[0058] Preferably, the polymerization reaction further includes a post-polymerization step, and the post-polymerization method includes: evacuating the system to -0.01MPa--0.1MPa (for example, it can be -0.01MPa, -0.02MPa, -0.04MPa, -0.06MPa, -0.08MPa or -0.1MPa, etc.), adjusting the temperature to 275°C-285°C (for example, it can be 275°C, 276°C, 277°C, 278°C, 279°C, 280°C, 281°C, 282°C, 283°C, 284°C or 285°C, etc.), keep it for 100s-1200s (for example, it can be 100s, 200s, 300s, 400s, 500s, 600s, 700s, 800s, 900s, 1000s, 1100s or 1200s, etc.), then stop stirring, continue to vacuum to achieve the purpose of liquid phase viscosity increase, let it stand for 1min-10min (for example, it can be 1min, 2min, 3min, 4min, 5min, 6min, 7min, 8min, 9min or 10min, etc.), then pass nitrogen to discharge the material.

[0059] Compared with the prior art, the present invention has the following beneficial effects:

[0060] In the present invention, the structure of polyamide is designed, and a polyamide composition having good flame retardancy and antibacterial properties is obtained by compounding a polyamide containing a phosphorus-based flame retardant structure and a non-reactive phosphorus-based flame retardant (zinc diethyl hypophosphite) without adding other antibacterial agents. The adverse effect of a large amount of reactive flame retardant added on the polymerization process of polyamide is solved, and the effect of the additional addition of antibacterial agents on the mechanical properties and spinning properties of flame-retardant polyamide is solved. The viscosity of the polyamide composition obtained is 2.40-2.65, the vertical combustion grade is V-0, the oxygen index is 30-34%, the full roll rate is 93.0-97.5%, the fiber strength is 5.0-5.5 g / d, and the antibacterial rate is 97.0-99.9%. DETAILED DESCRIPTION

[0061] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0062] The sources of some components in the embodiments and comparative examples are as follows:

[0063] Diethyl zinc phosphate and diethyl aluminum phosphinate were purchased from Clariant, ground using a ball mill, and the D 95 The particle size was tested to obtain diethyl zinc phosphate and diethyl aluminum phosphinate with the required particle size as described below.

[0064] Zinc diethylphosphite 1: ZDP-1, D 95 Particle size: 0.1 μm;

[0065] Zinc diethylphosphite 2: ZDP-2, D 95 Diameter: 0.2μm;

[0066] Zinc diethylphosphite 3: ZDP-3, D 95 0.4μm;

[0067] Zinc diethylphosphite 4: ZDP-4, D 95 0.6μm;

[0068] Zinc diethylphosphite 5: ZDP-5, D 95 0.8μm;

[0069] Zinc diethylphosphite 6: ZDP-6, D 95 1μm;

[0070] Zinc diethylphosphite 7: ZDP-7, D 95 1.5μm;

[0071] Zinc diethylphosphite 8: ZDP-8, unground, D 95 100μm;

[0072] Diethylaluminum hypophosphite: ADP, D 95 0.4μm;

[0073] Preparation Example 1-2

[0074] Preparation Examples 1-2 respectively provide a solution containing a reactive phosphorus-based flame retardant salt, and the preparation method is as follows:

[0075] The reactive phosphorus flame retardant, diamine and water are stirred and mixed at 200 rpm, and salt-forming reaction is carried out at 80° C. for 4 hours to obtain the solution containing the reactive phosphorus flame retardant salt;

[0076] The molar ratio of the reactive phosphorus flame retardant to the diamine is 1:1.05;

[0077] Among them, in Preparation Example 1, the reactive phosphorus-based flame retardant is

[0078]

[0079] (R2 is CH2CHCH2), the diamine is hexamethylenediamine, and the mass concentration of the reactive phosphorus-based flame retardant salt in the obtained solution containing the reactive phosphorus-based flame retardant salt is 55%;

[0080] In Preparation Example 2, the reactive phosphorus flame retardant is

[0081]

[0082] (R1 is CH), the diamine is pentamethylenediamine, and the mass concentration of the reactive phosphorus-based flame retardant salt in the obtained solution containing the reactive phosphorus-based flame retardant salt is 55%.

[0083] Preparation Example 3

[0084] This preparation example provides a polyamide 66 salt solution, and the preparation method is as follows:

[0085] Mix hexamethylenediamine, adipic acid and water, and perform a neutralization and salt-forming reaction at 80° C. for 1.5 hours to obtain a polyamide 66 salt solution with a mass concentration of 55%;

[0086] Wherein, the molar ratio of hexamethylenediamine to adipic acid is 1.02:1.

[0087] Example 1-Example 9, Comparative Example 1-Comparative Example 4

[0088] Example 1 to Example 9 and Comparative Example 1 to Comparative Example 4 respectively provide an antibacterial halogen-free flame retardant polyamide composition, and the amount and specific selection of each raw material component of the antibacterial halogen-free flame retardant polyamide composition are shown in Table 1 and Table 2 below. The amount of each component in Table 1 and Table 2 is in parts by weight.

[0089] The preparation method of the antibacterial halogen-free flame-retardant polyamide composition is as follows:

[0090] The polyamide 66 salt solution, the solution containing the reactive phosphorus flame retardant salt and the non-reactive phosphorus flame retardant are stirred and mixed, and then a polymerization reaction is carried out at 284° C. for 3 hours. The reaction system is evacuated to -0.08 MPa, and the temperature is adjusted to 280° C. and kept for 900 seconds. Then, the stirring is stopped, and the evacuation is continued to achieve the purpose of liquid phase viscosity increase. After standing for 5 minutes, the material is discharged through nitrogen to obtain the antibacterial halogen-free flame retardant polyamide composition.

[0091] The preparation method of Example 1 is as follows:

[0092] 4785 kg of polyamide 66 salt solution (mass concentration of 55%), 224 kg of solution containing reactive phosphorus flame retardant salt (mass concentration of 55%) and 100 kg of non-reactive phosphorus flame retardant were stirred and mixed, and polymerization reaction was carried out at 284° C. for 3 hours, and then the reaction system was evacuated to -0.08 MPa, the temperature was adjusted to 280° C., and the stirring was stopped after maintaining for 900 seconds, and the evacuation was continued to achieve the purpose of liquid phase viscosity increase, and nitrogen was passed through the material after standing for 5 minutes to obtain the antibacterial halogen-free flame retardant polyamide composition;

[0093] Among them, it is calculated based on the conversion rate of polyamide 66 salt and reactive phosphorus flame retardant salt being 87%. In the antibacterial halogen-free flame retardant polyamide composition of Example 1, the mass percentage of phosphorus element in the polyamide with phosphorus flame retardant structure is 0.3%, and the mass percentage of non-reactive phosphorus flame retardant is 4%.

[0094] Examples 2-9 and Comparative Examples 1-4 The preparation method refers to Example 1, and antibacterial halogen-free flame-retardant polyamide compositions with different phosphorus contents are obtained by adjusting the addition amount of each raw material component, as shown in the following Table 1-2.

[0095] The performance of the antibacterial halogen-free flame-retardant polyamide composition provided in the above embodiments and comparative examples was tested, and the specific testing method is as follows:

[0096] Viscosity: Tested according to GB / T 12006.1-2009;

[0097] Vertical burning rating: tested according to UL94;

[0098] Oxygen index: tested according to GB / T 2406.2-2009;

[0099] Full roll rate (%): Full roll rate refers to the proportion of the weight of the silk cake to the predetermined weight during the winding process. In the production process, the full roll rate directly affects the production efficiency and product quality. The higher the ideal full roll rate, the less waste in the production process and the higher the production efficiency.

[0100] Fiber strength (g / d): tested according to GB / T 14344-2008;

[0101] Antibacterial rate: tested according to GB / T 20944.3-2008.

[0102] The above performance tests are shown in Table 1-2 below:

[0103] Table 1

[0104]

[0105] Table 2

[0106]

[0107]

[0108] As can be seen from the above content, the present invention designs the structure of polyamide, and obtains a polyamide composition with good flame retardancy and antibacterial properties by compounding a polyamide with a phosphorus-containing flame retardant structure and a non-reactive phosphorus-containing flame retardant (diethyl zinc hypophosphite) without adding other antibacterial agents. The adverse effect of a large amount of reactive flame retardant added on the polyamide polymerization process is solved, and the effect of additional addition of antibacterial agents on the mechanical properties and spinning properties of flame-retardant polyamide is solved. The viscosity of the polyamide composition obtained is 2.40-2.65, the vertical combustion grade is V-0, the oxygen index is 30-34%, the full roll rate is 93.0-97.5%, the fiber strength is 5.0-5.5g / d, and the antibacterial rate is 97.0-99.9%.

[0109] It can be seen from Example 1, Examples 6-9 and Comparative Example 1 and Comparative Example 5 that the present invention controls the D 95 The particle size is ≤1μm, further 0.2μm~0.8μm, which optimizes the comprehensive performance of the polyamide composition. The viscosity of the polyamide composition obtained is 2.40~2.65, the vertical combustion grade is V-0, the oxygen index is 30-34%, the full roll rate is 96.0~97.3%, the fiber strength is 5.1~5.5g / d, and the antibacterial rate is 98.0~99.9%.

[0110] It can be seen from Example 1 and Comparative Example 2 that the present invention uses zinc diethyl hypophosphite to prepare a polyamide composition having both flame retardancy and antibacterial properties.

[0111] It can be seen from Example 1 and Comparative Examples 3-4 that the present invention obtains a polyamide composition having good flame retardancy and antibacterial properties by compounding a polyamide containing a phosphorus-based flame retardant structure and a non-reactive phosphorus-based flame retardant without adding other antibacterial agents, and the polyamide composition has good mechanical properties.

[0112] In summary, the present invention designs the specific composition of the polyamide composition, and compounding the polyamide containing the phosphorus flame retardant structure and the non-reactive phosphorus flame retardant, and controlling the D 95 When the particle size is within a specific range, a polyamide composition with good flame retardancy, antibacterial properties and mechanical properties is obtained without the need to add other antibacterial agents.

[0113] The applicant declares that the present invention illustrates the detailed process flow of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process flow to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. An antibacterial halogen-free flame-retardant polyamide composition, characterized in that: The antibacterial halogen-free flame-retardant polyamide composition comprises a polyamide containing a phosphorus-based flame-retardant structure and a non-reactive phosphorus-based flame retardant; The non-reactive phosphorus-based flame retardant includes diethyl zinc hypophosphite; The non-reactive phosphorus-based flame retardant D 95 Particle size ≤1μm.

2. The antibacterial halogen-free flame-retardant polyamide composition according to claim 1, characterized in that: The non-reactive phosphorus-based flame retardant D 95 The particle size is 0.2μm~0.8μm.

3. The antibacterial halogen-free flame-retardant polyamide composition according to claim 1 or 2, characterized in that: The mass percentage of phosphorus in the phosphorus-containing flame-retardant polyamide is 0.15%-0.55%.

4. The antibacterial halogen-free flame-retardant polyamide composition according to any one of claims 1 to 3, characterized in that: Taking the mass percentage of the antibacterial halogen-free flame-retardant polyamide composition as 100%, the mass percentage of the non-reactive phosphorus-based flame retardant is 2%-10%, preferably 3%-5%.

5. The antibacterial halogen-free flame-retardant polyamide composition according to any one of claims 1 to 4, characterized in that: The polyamide containing phosphorus-based flame retardant structure comprises a polyamide 66 structure and a phosphorus-based flame retardant structure; The raw materials for preparing the phosphorus-based flame retardant structure include a reactive phosphorus-based flame retardant and a diamine; The reactive phosphorus-based flame retardant includes a DOPO-based flame retardant and / or a DDP-based flame retardant; Preferably, the DOPO-based flame retardant has a structure as shown in the following formula I: R1 is selected from C1-C15 alkylene; Preferably, the DDP-based flame retardant has a structure as shown in the following formula II: R2 is selected from C1-C15 alkylene; Preferably, the diamine has carbon atoms of C2-C14, and more preferably is any one of pentamethylenediamine, hexamethylenediamine, octanediamine, decanediamine or 2-methyloctanediamine, or a combination of at least two thereof.

6. A method for preparing the antibacterial halogen-free flame-retardant polyamide composition according to any one of claims 1 to 5, characterized in that: The preparation method comprises the following steps: The antibacterial halogen-free flame-retardant polyamide composition is obtained by mixing a solution containing polyamide 66 salt, a solution containing reactive phosphorus-based flame retardant salt and a non-reactive phosphorus-based flame retardant, and then performing a polymerization reaction.

7. The preparation method according to claim 6, characterized in that: The solution containing the reactive phosphorus-based flame retardant salt is prepared by the following method, which comprises the following steps: The reactive phosphorus-based flame retardant, diamine and solvent are mixed and then subjected to a salt-forming reaction to obtain the solution containing the reactive phosphorus-based flame retardant salt.

8. The preparation method according to claim 7, characterized in that: The molar ratio of the reactive phosphorus flame retardant to the diamine is 1:(1.0-1.2); Preferably, the mass ratio of the reactive phosphorus-based flame retardant to the solvent is 1:(1.0-2.0); Preferably, the solvent comprises water; Preferably, the temperature of the salt-forming reaction is 60° C.-90° C., and the time is 2 h-5 h.

9. The preparation method according to claim 6 or 7, characterized in that: The mass concentration of polyamide 66 salt in the solution containing polyamide 66 salt is 50%-60%; Preferably, the mass concentration of the reactive phosphorus-based flame retardant salt in the solution containing the reactive phosphorus-based flame retardant salt is 40%-60%; Preferably, the raw materials for preparing the antibacterial halogen-free flame-retardant polyamide composition include the following components in parts by weight: 90-100 parts of polyamide 66 salt; 3 to 10 parts of reactive phosphorus flame retardant salt; 3 to 10 parts of non-reactive phosphorus flame retardant.

10. The preparation method according to any one of claims 6 to 9, characterized in that: The polymerization temperature is 275°C-290°C; Preferably, the polymerization reaction time is 2h-4h.

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