Polyamide composition as well as preparation method and application thereof

Abstract

The invention discloses a polyamide composition, the polyamide composition contains polyamide, an X component phosphorus antioxidant and a Y component hindered amine antioxidant, and the weight ratio of the X component to the Y component is 0.005-5.000. The polyamide composition has excellent oxidation resistance and moisture absorption performance.

Description

Technical Field

[0001] The present invention relates to a polyamide composition, in particular to a polyamide composition having both high oxidation resistance and high hygroscopicity. Background Art

[0002] Polyamide fiber is one of the earliest synthetic fibers to enter industrial production worldwide. Polyamide boasts excellent mechanical properties, chemical resistance, abrasion resistance, and moisture absorption, making it widely used in clothing, rubber skeleton materials, airbags, and military products. However, polyamide is susceptible to oxidative degradation during synthesis, product preparation, storage, and use, resulting in molecular weight loss and color changes. Therefore, improving the thermal and oxidative stability of polyamide has long been a focus of research.

[0003] Adding antioxidants is one of the effective means to prevent polyamide oxidative degradation. Chinese patent CN113564745A discloses a polyamide fiber, which is mainly made of a polyamide copolymer and an antioxidant β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate n-octadecyl ester through melt spinning. The antioxidant is used to reduce the oxidation and yellowing of the polyamide copolymer during the melt spinning process. However, this patent only adds a hindered phenol antioxidant, and the antioxidant effect is not outstanding. It cannot effectively prevent the yellowing phenomenon during the melt spinning process. Therefore, it is necessary to improve the existing antioxidant formula, or improve the ratio of the compound antioxidant, and improve the yellowing phenomenon while maintaining the original mechanical properties of the product. Summary of the Invention

[0004] The object of the present invention is to provide a polyamide composition having both good oxidation resistance and hygroscopicity and a preparation method thereof, wherein the polyamide composition can be used to prepare fibers having excellent oxidation resistance and hygroscopicity.

[0005] The technical solution of the present invention is:

[0006] A polyamide composition contains polyamide, a phosphorus antioxidant (component X) and a hindered amine antioxidant (component Y), wherein the weight ratio of component X to component Y is 0.005 to 5.000.

[0007] The X component preferably accounts for 50 to 5000 ppm of the polyamide composition.

[0008] The polyamide composition preferably further contains a hindered phenol antioxidant as component Z, and the weight ratio of component X to the sum of component Y and component Z is preferably 0.003 to 2.000.

[0009] The Z component preferably accounts for 10,000 ppm or less of the polyamide composition.

[0010] The weight ratio of -NH- groups to the sum of the X component, the Y component, and the Z component in the polyamide composition is preferably 3 to 150.

[0011] The present invention also discloses two methods for preparing polyamide compositions. One method is to add a phosphorus antioxidant (component X) and a hindered amine antioxidant (component Y) at any stage of the polyamide synthesis process, wherein the weight ratio of component X to component Y is 0.005 to 5.000.

[0012] Another method is to mix polyamide resin, X component phosphorus antioxidant and Y component hindered amine antioxidant, and then use an extruder to granulate to obtain a polyamide resin composition, wherein the weight ratio of X component to Y component is 0.005 to 5.000.

[0013] The polyamide composition of the present invention has good antioxidant performance, is not prone to yellowing, and has good hygroscopicity, and can be used to prepare fibers. DETAILED DESCRIPTION

[0014] Elements such as carbon, hydrogen, and nitrogen in the molecular structure of polyamide react chemically with oxygen to generate alkyl radicals, peroxide radicals, and amino radicals. Alkyl radicals can further oxidize to peroxide radicals. However, peroxide radicals are unstable, and some of them can further generate hydroperoxides, accelerating the oxidative decomposition of polyamide. Consequently, polyamide is susceptible to oxidative degradation during thermal processing and use, resulting in a decrease in relative molecular weight and color change. Improving the thermo-oxidative stability of polyamide has long been a focus of research. Adding antioxidants is an effective means of preventing oxidation in polymers. Currently, commonly used antioxidants for polymers include phosphorus-containing compounds, hindered phenol compounds, and hindered amine compounds. However, when these antioxidants are directly applied to polyamide, the antioxidant effect remains limited, particularly at high processing temperatures, where they fail to effectively prevent yellowing. Furthermore, the addition of antioxidants reduces the content of -NH- groups in the polyamide, impairing its hygroscopic properties. Therefore, there is a need to improve the existing antioxidant formulations and apply them to polyamides to improve oxidative degradation without reducing hygroscopicity.

[0015] The present invention provides a polyamide composition having both antioxidant and hygroscopic properties. The composition comprises a polyamide, a phosphorus-based antioxidant (component X), and a hindered amine antioxidant (component Y). The phosphorus-based antioxidant (component X) can capture hydroperoxides, and the hindered amine antioxidant (component Y) can simultaneously capture peroxide radicals, alkyl radicals, and amino radicals. Through the synergistic effect of components X and Y, the polyamide composition of the present invention exhibits excellent antioxidant properties.

[0016] In addition to the above effects, the X component can also inhibit the oxidation of the Y component in air, thereby improving the antioxidant efficiency of the Y component and effectively inhibiting the yellowing of the polyamide composition. To achieve the above effects, the present invention limits the weight ratio of the X component to the Y component to 0.005 to 5.000. Under the conditions that the content of the Y component and other conditions are the same, when the weight ratio of the X component to the Y component is greater than 5.000, after the task of capturing hydroperoxides and inhibiting the oxidation of the Y component is completed, some of the X component will still remain alone. This not only increases the preparation cost of the polyamide composition, but also causes the polyamide composition to increase viscosity and produce gels during subsequent processing, resulting in large losses to processing equipment, and the strength of the resulting product (such as a fiber or film) is too low, making the production and processing of the product difficult. When the weight ratio of the X component to the Y component is less than 0.005, the X component is too small to fully capture the hydroperoxide and inhibit the oxidation of the Y component, resulting in a weakened overall antioxidant effect and failure to inhibit the yellowing of the polyamide composition. Taking into comprehensive consideration the cost, processability, and yellowing inhibition effect of the polyamide composition, the weight ratio of the component X to the component Y is preferably 0.010 to 2.000.

[0017] In addition to meeting the aforementioned weight ratio of component X to component Y, further controlling the content of component X can yield a superior antioxidant effect. This is because if the content of component X is too low, it will not adequately capture hydroperoxides and effectively inhibit yellowing of the polyamide composition. If the content of component X is too high, a large amount of component X will reduce the concentration of hygroscopic -NH- groups in the polyester composition, resulting in reduced hygroscopicity of the polyamide composition. Furthermore, during subsequent processing, component X will tend to increase viscosity and form gels, resulting in significant wear and tear on processing equipment, reduced strength of the resulting product (such as a fiber or film), and increased difficulty in manufacturing and processing the product. Therefore, the proportion of component X in the polyamide composition of the present invention is preferably 50 to 5000 ppm, more preferably 50 to 1000 ppm.

[0018] To obtain a polyamide composition with excellent antioxidant properties, the content of component Y must be moderately low, otherwise it will not fully capture peroxide radicals, alkyl radicals, and amino radicals. Furthermore, the content of component Y must be moderately high, otherwise it will increase the production cost of the polyamide composition. Excessive amounts of component Y will reduce the intermolecular forces within the polyamide composition, resulting in a decrease in the viscosity of the polyamide composition. The content of component Y in the polyamide composition of the present invention is preferably 500 to 10,000 ppm, more preferably 1,000 to 5,000 ppm.

[0019] The present invention has no particular limitation on the phosphorus-based antioxidant of the X component. From the perspectives of improving the antioxidant properties of the polyamide composition, maintaining hygroscopicity and processability, poly(dipropylene glycol) phenyl phosphite (antioxidant PDP), bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate (antioxidant PEP36), tris(2,4-di-tert-butylphenyl) phosphite (antioxidant IR168), bis(2,4,6-tri-tert-butylphenyl) pentaerythritol diphosphite (antioxidant 633), tetra(2,4- At least one of di-tert-butylphenol)-4,4'-biphenyl diphosphite (antioxidant P-EPQ), 3,9-dioctadecyloxy-2,4,8,10-tetrahydro-3,9-diphosphaspiro[5.5]undecane (antioxidant 618), and bis(2,4-dicumylphenyl)pentaerythritol diphosphite (antioxidant 9228), preferably at least one of tris(2,4-di-tert-butylphenyl)phosphite (antioxidant IR168) and bis(2,4-dicumylphenyl)pentaerythritol diphosphite (antioxidant 9228).

[0020] The present invention has no particular limitation on the hindered amine antioxidant of the Y component. From the perspectives of improving the antioxidant properties of the polyamide composition, maintaining hygroscopicity and processability, preferred are poly{[6-[(1,1,3,3-tetramethylbutyl)amino]]-1,3,5-triazine-2,4-[(2,2,6,6-tetramethyl-piperidinyl)imino]-1,6-hexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino]} (HS944), poly(4-hydroxyethyl-2,2,6,6-tetramethyl-1-piperidinethanol) succinate (UV622), 2,2,6,6-tetramethyl-1-(undecyloxy)-4-piperidinol carbonate (LA-81) and poly(4-hydroxyethyl-2,2,6,6-tetramethyl-1-piperidinol) succinate (UV622). ), 1,3,5-triazine-2,4,6-triamine-NN"'-[1,2-ethanediylbis[[[4,6-bis[butyl(1,2,2,6,6-pentamethyl-4-piperidinyl)amino]-1,3,5-triazin-2-yl]imino]3,1-propanediyl]]-bis[N'-N"-dibutyl-N',N"-bis(1,2,2,6,6-pentamethyl-4-piperidinyl)] (HALS119), N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,3-benzenedicarboxamide (UV660), and bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate (TINUVIN770).

[0021] To fully capture alkyl and amino radicals in the polyamide composition and effectively inhibit oxidative yellowing of the polyamide composition, the polyamide composition of the present invention preferably also contains a hindered phenolic antioxidant, component Z. However, the content of component Z should not be too high, as this increases the production cost of the polyamide composition. Furthermore, excess component Z can be oxidized in air to form quinone compounds, which can easily cause yellowing of the polyamide composition. The content of component Z in the polyamide composition of the present invention is preferably 10,000 ppm or less, and more preferably 5,000 ppm or less.

[0022] At the same time, according to the mechanism of action of each antioxidant, in order to inhibit the compatibility of the antioxidant and polyamide from being affected by excessive decomposition and cross-linking reaction of each antioxidant component, and taking comprehensive consideration of the cost, strength, and yellowing inhibition effect of the polyamide composition, the present invention also preferably has a weight ratio of the X component to the sum of the Y component and the Z component (X component / (Y component + Z component)) of 0.003 to 2.000, and the total amount of the X component, the Y component, and the Z component preferably accounts for 1000 ppm to 30000 ppm of the polyamide composition.

[0023] The present invention has no particular limitation on the hindered phenol antioxidant of the Z component. From the perspectives of improving the antioxidant properties of the polyamide composition, maintaining hygroscopicity, and processability of the polyamide composition product, preferred are pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (antioxidant 1010), octadecylβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (antioxidant 1076), 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene (antioxidant 330), 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H )-trione (Antioxidant 1790), N,N'-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine (Antioxidant 1024), 3,9-bis[1,1-dimethyl-2-[(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane (AO80), 2,2'-methylenebis(4-methyl-6-tert-butylphenol) (Antioxidant 2246), 2,6-di-tert-butyl-4-methylphenol (Antioxidant BHT), N,N'-(hexane-1,6-diyl)bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide] (Antioxidant 1098).

[0024] While controlling the ratio and content range of antioxidant components X, Y, and Z can effectively enhance antioxidant activity, improper addition can negatively impact the hygroscopicity of the polyamide composition. Polyamides contain -NH groups, which readily form hydrogen bonds with water molecules and therefore exhibit excellent hygroscopicity. However, excessive amounts of antioxidants in a polyamide composition can reduce the concentration of -NH groups, thereby impacting the composition's hygroscopicity. Therefore, the weight ratio of -NH groups to the sum of components X, Y, and Z in the polyamide—that is, the ratio of -NH groups to (components X + Y + Z)—needs to be adjusted to ensure that the polyamide composition maintains its antioxidant properties while maintaining its hygroscopicity. If this ratio is too low, the total amount of antioxidant is relatively high relative to the amount of -NH groups in the polyamide, and the hygroscopicity of the polyamide composition is more easily affected by the antioxidant. If this ratio is too high, the total amount of antioxidant is relatively low relative to the amount of -NH groups in the polyamide, and the antioxidant properties of the polyamide composition are not effectively improved. The weight ratio of the -NH- group to the sum of the X component, the Y component, and the Z component of the present invention is preferably 3 to 150.

[0025] The polyamide composition described in the present invention can be a material commonly used in the prior art, such as polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 610, polyamide 612, polyamide 46, polyamide 1010, polyamide 54, polyamide 56, polyamide 59, polyamide 510, polyamide 511, polyamide 512, polyamide 513, polyamide 514, polyamide 515, polyamide 516, polyamide 517, polyamide 518, etc.

[0026] The invention also discloses a preparation method of the polyamide composition. According to the adding time, the antioxidant can be added during the polymerization process or can be added by blending.

[0027] The method of adding the antioxidant during the polymerization process refers to adding the phosphorus antioxidant component X and the hindered amine antioxidant component Y at any stage of the polyamide synthesis process, and the weight ratio of the component X to the component Y is 0.005 to 5.000.

[0028] Another blending and adding method is to mix the polyamide resin, the phosphorus-based antioxidant (component X) and the hindered amine antioxidant (component Y), and then extrude and granulate them using an extruder to obtain a polyamide resin composition, wherein the weight ratio of the component X to the component Y is 0.005 to 5.000.

[0029] In the above two adding methods, a hindered phenol antioxidant as component Z may also be added. The weight ratio of component X to the sum of component Y and component Z is preferably 0.003 to 2.000.

[0030] The polyamide composition can be prepared by conventional methods. The present invention provides an example of obtaining a polyamide resin composition by copolymerization:

[0031] (1) preparing a salt solution of aliphatic diamine, aliphatic diacid and ion exchange water, wherein the temperature of the salt solution shall not exceed 60° C. and the concentration of the salt solution shall be between 30% and 70%;

[0032] (2) The obtained salt solution is concentrated and then subjected to polymerization reaction, first reacting at 190-260° C. and 1.3-2.2 MPa for 1-4 hours, then reducing the pressure to normal pressure and controlling the temperature at 230-300° C., and finally continuing the reaction at -0.1-0 MPa for 0.5-3 hours to obtain a polyamide resin composition.

[0033] The antioxidant can be added before the salt solution is prepared, concentrated or polymerized, or can be added during the polymerization process. In addition, a catalyst, end-capping agent, matting agent, weathering agent, etc. can also be added during the polymerization process.

[0034] The raw material of the polyamide can be caprolactam, aminoundecanoic acid, laurolactam, or a combination of a dibasic acid and a diamine, and the diamine can be one or more of pentamethylenediamine, decanediamine, and hexamethylenediamine; the dibasic acid is selected from one of succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, and octadecanedioic acid, preferably one or more of adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, or octadecanedioic acid.

[0035] The polyamide composition of the present invention has good antioxidant performance, is not prone to yellowing, has good hygroscopicity, and is good in spinnability, and can be used for fibers.

[0036] The testing method involved in the present invention is as follows:

[0037] 1. Yellowing value

[0038] A polyamide composition was melt-spun at 285°C and 2500 m / s to produce polyamide yarn. The resulting yarn was then stretched to an elongation of 35% to 40% to produce polyamide fiber of type 36T-33f. The polyamide fiber was then formed into a 26-gauge tubular braid, scoured, dried, and then treated at 200°C for 10 minutes. The yellowing value of the tubular braid before and after heat treatment was measured using a Datacolor 650 spectrophotometer (manufactured by Datacolor Asia Pacific (HK) Ltd.).

[0039] 2. Strength

[0040] The polyamide composition was melt-spun at 285°C and 2500 m / s to produce polyamide yarn. The resulting yarn was then stretched to an elongation of 35% to 40% to obtain polyamide fiber of variety 36T-33f. The strength of the polyamide fiber was tested using a tensile testing machine (Tensilon, manufactured by Intech) at a test speed of 200 mm / min and a stress-strain curve measured with a distance of 200 mm between the two clamps. The load at break was read and divided by the initial fineness to calculate the strength. This operation was repeated five times using the same standard, and the simple average of the results was calculated.

[0041] 3. Types and contents of antioxidants

[0042] The polyamide composition was dissolved in dimethyl sulfoxide (DMSO) and centrifuged to obtain an antioxidant mixture, which was then analyzed by high performance liquid chromatography (HPLC) (Agilent 1290 infinity II, USA). The type and content of the antioxidants were determined by chromatographic analysis.

[0043] 4. Moisture absorption rate difference ΔMR

[0044] The polyamide composition is melt-spun at 285°C and 2500 m / s to obtain polyamide yarn, and then the obtained yarn is stretched so that its elongation after stretching is between 35% and 40%, thereby obtaining polyamide fiber of variety 36T-33f. Finally, the polyamide fiber is made into a tubular braid (26 needles).

[0045] (1) Select three samples of woven fabric weighing approximately 1 g, place them in a weighing bottle of known mass, and place them in a dryer at 60°C. Remove the bottle cap and allow it to dry for 30 minutes. Then, replace the bottle cap and take out the weighing bottle.

[0046] (2) Place the weighing bottle in a constant temperature and humidity chamber at 20°C and 65% RH. Remove the bottle cap and allow it to equilibrate for 24 hours. Then replace the bottle cap and take out the weighing bottle. Weigh the sample using a precision balance. The mass obtained minus the mass of the weighing bottle is the sample weight W1.

[0047] (3) Place the weighing bottle in a constant temperature and humidity chamber at 30°C and 90% RH, remove the bottle cap, and allow it to equilibrate for 24 hours. Then replace the bottle cap and take out the weighing bottle. Weigh the sample using a precision balance. The mass of the weighed bottle minus the mass of the weighing bottle is the sample weight W2.

[0048] (4) Place the weighing bottle in a dryer at 105°C, remove the bottle cap, and dry for 2 hours. Then, put the bottle cap back on and take it out. After cooling it in a drying dish at room temperature, use the same precision balance to weigh it. The mass obtained minus the mass of the weighing bottle is the sample weight W3.

[0049] (5) Calculation:

[0050] MR1=(W1-W3) / W3

[0051] MR2=(W2-W3) / W3

[0052] The moisture absorption rate difference ΔMR (%) = MR2 - MR1, and the result is the average value of the three samples.

[0053] 5. -NH- content in polyamide

[0054] A certain amount of polyamide composition was taken and the antioxidant was removed by filtration with toluene solvent to obtain polyamide. The hydrogen spectrum of the polyamide was measured using H-NMR (AVANCE 600, Bruker, Germany), and the characteristic peaks of the hydrogen element (the characteristic peak of the hydrogen element on -NH- and the characteristic peak of the hydrogen element on -CH2) were found. The content of -NH- in the polyamide was calculated based on the peak area.

[0055] The abbreviations of the antioxidants involved in the embodiments of the present invention are as follows.

[0056] X ingredient:

[0057] (1) Poly(dipropylene glycol) phenyl phosphite (abbreviated as antioxidant PDP);

[0058] (2) Tris(2,4-di-tert-butylphenyl)phosphite (abbreviated as antioxidant IR168);

[0059] (3) Bis(2,4-dicumylphenyl)pentaerythritol diphosphite (abbreviated as antioxidant 9228);

[0060] (4) Bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphate (abbreviated as antioxidant PEP36).

[0061] Y ingredient:

[0062] (1) Poly{[6-[(1,1,3,3-tetramethylbutyl)amino]]-1,3,5-triazine-2,4-[(2,2,6,6-tetramethyl-piperidinyl)imino]-1,6-hexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino]} (abbreviation: HS944);

[0063] (2) Poly(4-hydroxyethyl-2,2,6,6-tetramethyl-1-piperidinylethanol) succinate (abbreviation: UV622);

[0064] (3) Bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate (abbreviation: TINUVIN770);

[0065] (4) 2,2,6,6-tetramethyl-1-(undecyoxy)-4-piperidinol carbonate (abbreviation: LA-81);

[0066] (5) N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,3-benzenedicarboxamide (abbreviation: UV-660).

[0067] Z ingredient:

[0068] (1) 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione (abbreviated as Antioxidant 1790);

[0069] (2) 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene (abbreviated as antioxidant 330);

[0070] (3) N,N'-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine (abbreviated as antioxidant 1024);

[0071] (4) 3,9-bis[1,1-dimethyl-2-[(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane (abbreviation: AO80);

[0072] (5) N,N'-(hexane-1,6-diyl)bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide] (abbreviated as:

[0073] Antioxidant 1098).

[0074] Example 1

[0075] Pentamethylenediamine, adipic acid, and ion-exchanged water were prepared into a 60% saline solution, which was then placed in a concentrator for concentration. Component X (antioxidant PDP) and component Y (HS944) were then added and transferred to a polymerization reactor for polymerization. The reactor temperature was set at 290°C. The temperature was initially increased while maintaining the pressure at 2 MPa. When the reactor temperature reached 250°C, the pressure was released. After reaching atmospheric pressure, the pressure was reduced and the set temperature was set to 285°C. After 5 minutes, the pressure was reduced to 30 kPa and maintained until the target viscosity was reached. The polyamide resin composition was then discharged. The final reactor temperature was 285°C. Component X accounted for 100 ppm of the polyamide composition, and component Y accounted for 1000 ppm. The specific formulation and physical properties are shown in Table 1.

[0076] Examples 2 to 29

[0077] The preparation method was the same as in Example 1, except that the amount and type of antioxidants were varied for polymerization. The specific formulation and physical properties are shown in Tables 1 and 2.

[0078] Example 30

[0079] Polyamide 56 (PA56) chips, component X (antioxidant IR168), component Y (TIVUVIN770), and component Z (antioxidant 1098) were added to a mixer, mixed, and extruded into pellets. Component X accounted for 300 ppm of the polyamide composition, component Y accounted for 2500 ppm of the polyamide composition, and component Z accounted for 2500 ppm of the polyamide composition. The specific formulation and physical properties are shown in Table 2.

[0080] Examples 31 to 35

[0081] The preparation method is the same as that of Example 30. The specific formula and physical properties are shown in Tables 2 and 3.

[0082] Examples 36 to 39

[0083] The preparation method was the same as in Example 1, except that the amount and type of antioxidant were changed for polymerization. The specific formulation and physical properties are shown in Table 3.

[0084] Comparative Example 1

[0085] The preparation method was the same as in Example 1, but without adding any X component, to prepare a polyamide composition. The specific formulation and physical properties are shown in Table 3.

[0086] Since no X component antioxidant is added, the polyamide has poor antioxidant properties and is prone to yellowing.

[0087] Comparative Example 2

[0088] The preparation method was the same as in Example 1, but without adding any component Y, to obtain a polyamide composition. The specific formulation and physical properties are shown in Table 3.

[0089] Since no Y component antioxidant is added, the polyamide has poor antioxidant properties and is prone to yellowing.

[0090] Comparative Example 3

[0091] The preparation method was the same as in Example 1 to obtain a polyamide composition. The specific formulation and physical properties are shown in Table 3.

[0092] Since the weight ratio of the sum of component X and component Y is too small, the added antioxidant cannot effectively inhibit the yellowing of the polyamide composition.

[0093] Comparative Example 4

[0094] The preparation method was the same as in Example 1 to obtain a polyamide composition. The specific formulation and physical properties are shown in Table 3.

[0095] Since the weight ratio of the sum of the X component and the Y component is too large, the strength of the obtained polyamide composition is low.

[0096]

[0097]

[0098]

Claims

1. A polyamide composition, characterized in that: The polyamide composition contains polyamide, a phosphorus antioxidant (component X) and a hindered amine antioxidant (component Y), and the weight ratio of the component X to the component Y is 0.005 to 5.

000.

2. The polyamide composition according to claim 1, wherein: The X component accounts for 50 to 5000 ppm of the polyamide composition.

3. The polyamide composition according to claim 1, wherein: The polyamide composition further contains a hindered phenol antioxidant as component Z, and the weight ratio of component X to the sum of component Y and component Z is 0.003 to 2.

000.

4. The polyamide composition according to claim 3, wherein: The Z component accounts for 10,000 ppm or less of the polyamide composition.

5. The polyamide composition according to claim 3 or 4, characterized in that: The weight ratio of -NH- groups to the sum of components X, Y and Z in the polyamide composition is 3 to 150.

6. The method for preparing the polyamide composition according to claim 1, wherein: The phosphorus antioxidant (X component) and the hindered amine antioxidant (Y component) are added at any stage of the polyamide synthesis process, and the weight ratio of the component X to the component Y is 0.005 to 5.

000.

7. The method for preparing the polyamide composition according to claim 1, wherein: A polyamide resin, a phosphorus-based antioxidant (component X) and a hindered amine antioxidant (component Y) are mixed and then extruded and granulated using an extruder to obtain a polyamide resin composition, wherein the weight ratio of the component X to the component Y is 0.005 to 5.

000.

8. Use of the polyamide composition according to claim 1 in fibers.

Images