A long carbon chain polyamide resin composition, a method for preparing the same, and an application thereof

Abstract

The present application provides a long carbon chain polyamide resin composition, which comprises a long carbon chain polyamide resin and a phosphorus compound; the content of phosphorus element in the long carbon chain polyamide resin composition is 50-350 ppm; the molecular structure of the long carbon chain polyamide resin comprises binary acid structural units and binary amine structural units; the binary acid structural units comprise aromatic binary acid structural units and long carbon chain aliphatic binary acid structural units; the mole percentage content of the aromatic binary acid structural units in the binary acid structural units is < 70%. In the present application, the long carbon chain polyamide resin composition has high proportion of smooth parts and excellent solvent resistance, and meanwhile, can have good toughness, strength and heat resistance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of engineering plastics, and particularly relates to a long carbon chain polyamide resin composition, a preparation method and application thereof. BACKGROUND

[0002] Long carbon chain polyamide refers to a polymer obtained by polymerization of at least one monomer with a main chain carbon atom number of 10 or more and other monomers, such as PA1010, PA1012, PA12, etc. Compared with ordinary polyamides, long carbon chain polyamides have small amide group density, good dimensional stability, excellent wear resistance and electrical properties, and the long carbon chain polyamide resin has good toughness and softness, high resilience, and low water absorption, so that the long carbon chain polyamide resin can maintain good toughness, hardness and electrical properties even in a humid environment. These excellent properties make the long carbon chain polyamide resin widely used in various fields such as automobiles, electronic appliances, machinery and military equipment.

[0003] Generally, when polyamide products are obtained from polyamide resin, injection molding, extrusion molding and other processes are required. However, whether it is injection molding or extrusion molding, it needs to be carried out at a high temperature. However, the long carbon chain polyamide resin has poor heat resistance, which leads to insufficient performance of the polyamide product after molding. In addition, the long carbon chain polyamide resin has poor strength and insufficient solvent resistance, which also affects the further application of the product in the field of chemical medium contact materials after molding. Therefore, in order to improve the heat resistance, strength and solvent resistance of the long carbon chain polyamide resin, rigid structures (such as benzene rings) are usually introduced. However, the introduction of too many rigid structures will cause the processing temperature to be too high, resulting in a low proportion of smooth parts and poor apparent quality of the molded product. In addition, due to the difference in reactivity, the introduction of rigid structures generally forms a long semi-aromatic sequence, which also affects the solvent resistance of the long carbon chain polyamide. In addition, the introduction of rigid structures will cause the toughness of the long carbon chain polyamide to deteriorate.

[0004] Therefore, it is an urgent problem in the art to develop a long carbon chain polyamide resin material with high proportion of smooth parts, good solvent resistance, and good strength, toughness and heat resistance. SUMMARY

[0005] In view of the deficiencies in the prior art, the purpose of the present application is to provide a long carbon chain polyamide resin composition, a preparation method and application thereof. The long carbon chain polyamide resin composition has high proportion of smooth parts and excellent solvent resistance, and can also have good toughness, strength and heat resistance.

[0006] To achieve this purpose, the technical scheme adopted by the present application is as follows:

[0007] In a first aspect, the present application provides a long carbon chain polyamide resin composition, which comprises a long carbon chain polyamide resin and a phosphorus compound; the content of phosphorus element in the long carbon chain polyamide resin composition is 50-350 ppm; the molecular structure of the long carbon chain polyamide resin comprises a diacid structural unit and a diamine structural unit; the diacid structural unit comprises an aromatic diacid structural unit and a long carbon chain aliphatic diacid structural unit; the mole percentage content of the aromatic diacid structural unit in the diacid structural unit is < 70%; and the number of main chain carbon atoms in the long carbon chain aliphatic diacid structural unit is > 6.

[0008] In the present application, the long carbon chain polyamide resin composition comprises a specific content of the phosphorus compound (the content of the phosphorus compound is determined by the content of phosphorus element), so that the long carbon chain polyamide resin has good solvent resistance, good toughness, strength and heat resistance, and after molding, the proportion of smooth parts is high, and the apparent quality of the product is good.

[0009] In the present application, the content of phosphorus element in the long carbon chain polyamide resin composition is 50-350 ppm, for example, it can be 50 ppm, 52 ppm, 54 ppm, 56 ppm, 58 ppm, 60 ppm, 62 ppm, 64 ppm, 66 ppm, 68 ppm, 70 ppm, 72 ppm, 74 ppm, 76 ppm, 78 ppm, 80 ppm, 82 ppm, 84 ppm, 86 ppm, 88 ppm, 90 ppm, 92 ppm, 94 ppm, 96 ppm, 98 ppm, 100 ppm, 102 ppm, 104 ppm, 106 ppm, 108 ppm, 110 ppm, 112 ppm, 115 ppm, 118 ppm, 120 ppm, 122 ppm, 125 ppm, 128 ppm, 130 ppm, 135 ppm, 140 ppm, 145 ppm, 150 ppm, 155 ppm, 160 ppm, 165 ppm, 170 ppm, 175 ppm, 180 ppm, 185 ppm, 190 ppm, 195 ppm, 200 ppm, 205 ppm, 210 ppm, 215 ppm, 220 ppm, 225 ppm, 230 ppm, 235 ppm, 240 ppm, 245 ppm, 250 ppm, 255 ppm, 260 ppm, 265 ppm, 270 ppm, 275 ppm, 280 ppm, 285 ppm, 290 ppm, 300 ppm, 310 ppm, 320 ppm, 330 ppm, 340 ppm, 350 ppm, or a range between any of the above values.

[0010] In the present application, the mechanism of the phosphorus compound is not clear, but it is speculated as follows: the phosphorus element can regulate the sequence of aromatic diacid and aliphatic diacid in the long carbon chain polyamide resin, so that the aromatic diacid sequence is short and randomly distributed in the polyamide molecular chain, thereby facilitating the improvement of the toughness and solvent resistance of the long carbon chain polyamide resin composition, and ensuring a high proportion of smooth parts; low content of phosphorus element, more by-products and impurities in the long carbon chain polyamide resin composition, resulting in a low proportion of smooth parts; and low content of phosphorus element may affect the reactivity of aromatic diacid and aliphatic diacid in the diacid group, resulting in long sequence of aromatic diacid, thereby resulting in poor toughness and solvent resistance of the long carbon chain polyamide resin composition; high content of phosphorus element may cause the long carbon chain polyamide resin composition to be easily decomposed during high temperature molding, thereby resulting in poor thermal stability of the product.

[0011] Preferably, the content of phosphorus element in the long carbon chain polyamide resin composition is 105-320 ppm.

[0012] In the present application, as long as the molecular structure of the phosphorus compound contains phosphorus element, there is no particular limitation on the source of phosphorus element and the type of added phosphorus compound; the phosphorus compound can be added during the synthesis of polyamide resin, or can be added after the synthesis of polyamide resin.

[0013] Preferably, the phosphorus compound includes at least one of phosphorus oxide, a phosphorus compound having a structure shown in Formula I, or a phosphorus compound having a structure shown in Formula II.

[0014]

[0015] wherein R1, R2, R3 are each independently selected from any one of -H, -OH, alkyl, cycloalkyl, alkoxy, aryl, -O-Ar or -OM; Ar is selected from aryl; M is selected from metal ion; R 11 , R 12 , R 13 are each independently selected from any one of alkyl, cycloalkyl or aryl.

[0016] In the present application, the number of carbon atoms of the alkyl group is 1-10, for example, it can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or a range between any of the above values; more preferably, the number of carbon atoms is 1-6.

[0017] In the present application, the number of carbon atoms of the cycloalkyl group is 3-8, for example, it can be 3, 4, 5, 6, 7, 8 or a range between any of the above values; more preferably, the number of carbon atoms is 3-6.

[0018] In the present application, the number of carbon atoms of the alkoxy group is 1-10, for example, it can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or a range between any of the above values; more preferably, the number of carbon atoms is 1-6.

[0019] In the present application, the number of carbon atoms of the aryl group is 6-20, for example, it can be 6, 8, 10, 12, 14, 16, 18, 20 or a range between any of the above values; more preferably, the number of carbon atoms is 6-15.

[0020] In the present application, the metal ion includes but is not limited to sodium ion, potassium ion, calcium ion, magnesium ion, lithium ion, zinc ion, etc.

[0021] Preferably, the oxide of phosphorus includes diphosphorus pentoxide and / or diphosphorus trioxide.

[0022] Preferably, the phosphorus compound with the structure shown in formula I includes at least one of phosphoric acid, phosphorous acid, hypophosphorous acid, phosphate ester compound, phosphite diester, phosphate salt compound, phosphite salt compound or hypophosphite salt compound.

[0023] Preferably, the phosphorus compound with the structure shown in formula II includes phosphite triester compound.

[0024] In the present application, the phosphate ester compound includes but is not limited to triphenyl phosphate, trimethyl phosphate, triethyl phosphate, cyclohexyl dimethyl phosphate, etc.; the phosphite diester includes but is not limited to dimethyl phosphite, diethyl phosphite, diphenyl phosphite, etc.; the phosphate salt compound includes but is not limited to potassium dihydrogen phosphate, potassium phosphate, dipotassium hydrogen phosphate, sodium dihydrogen phosphate, sodium phosphate, disodium hydrogen phosphate; the phosphite salt includes but is not limited to sodium phosphite, etc.; the hypophosphite salt includes but is not limited to sodium hypophosphite, etc.

[0025] In the present application, water is generated in the process of reacting diamine with diacid to generate polyamide, and the amount of generated water changes according to the type and ratio of monomers. In the reaction process, water needs to be discharged under high pressure, but the binding force of different phosphorus compounds with water is different, and a small amount of phosphorus compounds or derivatives thereof will be discharged in the high-pressure water discharge process. Therefore, the phosphorus content of the product obtained by different phosphorus compounds in the same formula and process will have certain differences, therefore, the content of phosphorus element in long-chain polyamide resin composition is affected by the addition amount of phosphorus compound, the type and ratio of monomers.

[0026] In the present application, the content of phosphorus element (ppm) in the long carbon chain polyamide resin composition = (the mass of phosphorus element in the added phosphorus compound - the mass of phosphorus element in the lost phosphorus compound) / (the mass of the diamine + the mass of the diacid + the mass of the monobasic acid end-capping agent - the mass of the discharged water). It should be noted that there is more or less difference between the theoretical content of phosphorus element and the actually detected content of phosphorus element, for example, the content of phosphorus element is also affected by the pollution of raw materials in the production, storage and transportation process, and the pollution of the production device in the synthesis process of the polyamide resin. Therefore, the content of phosphorus element in the present application is the actually detected content of phosphorus element in the long carbon chain polyamide resin composition.

[0027] Preferably, the mole percentage content of the aromatic diacid structural unit in the diacid structural unit is 10-66%, for example, it can be 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58%, 60%, 62%, 64%, 66% or a range between any of the above values; more preferably, the mole percentage content of the aromatic diacid structural unit is 20-60%.

[0028] Preferably, the aromatic diacid structural unit comprises terephthalic acid structural unit.

[0029] Preferably, the number of main chain carbon atoms in the long carbon chain aliphatic diacid structural unit is ≥8, for example, it can be 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or a range between any of the above values, more preferably, the number of main chain carbon atoms in the long carbon chain aliphatic diacid structural unit is 10-15.

[0030] Preferably, the long carbon chain aliphatic diacid structural unit comprises at least one of azelaic acid structural unit, sebacic acid structural unit, undecanedioic acid structural unit, dodecanedioic acid structural unit or tetradecanedioic acid structural unit.

[0031] Preferably, the number of main chain carbon atoms in the diamine structural unit is ≥4, for example, it can be 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or a range between any of the above values, more preferably, the number of main chain carbon atoms in the diamine structural unit is 4-10.

[0032] Preferably, the diamine structural unit comprises at least one of butanediamine structural unit, pentanediamine structural unit, hexanediamine structural unit or decanediamine structural unit.

[0033] In the present application, the molar ratio of the diacid structural unit and the diamine structural unit in the long carbon chain polyamide resin is (0.8-1.2):1, wherein the specific value in (0.8-1.2) can be 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2 or a range between any of the above values.

[0034] Preferably, the long carbon chain polyamide resin further comprises a monobasic acid-terminated diamine structural unit in the molecular structure thereof.

[0035] Preferably, the molar percentage content of the monobasic acid-terminated diamine structural unit is 1-6% of the diacid structural unit, for example, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6% or a range between any of the above values.

[0036] Preferably, the monobasic acid comprises at least one of stearic acid, benzoic acid, acetic acid, lauric acid or cyclohexane carboxylic acid.

[0037] Preferably, the long carbon chain polyamide resin composition further comprises an antioxidant.

[0038] Preferably, the mass content of the antioxidant in the long carbon chain polyamide resin composition is 0.05-0.3%, for example, 0.05%, 0.08%, 0.1%, 0.13%, 0.15%, 0.18%, 0.2%, 0.23%, 0.25%, 0.28%, 0.3% or a range between any of the above values.

[0039] In the present application, the antioxidant comprises, but is not limited to, at least one of N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexanediamine (antioxidant 1098), tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester (antioxidant 1010), tris[2.4-di-tert-butylphenyl]phosphite (antioxidant 168), n-octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (antioxidant 1076).

[0040] Preferably, the long carbon chain polyamide resin composition has a relative viscosity of 1.8-2.6, for example, 1.8, 1.82, 1.85, 1.88, 1.9, 1.92, 1.95, 1.98, 2.0, 2.02, 2.05, 2.08, 2.1, 2.12, 2.15, 2.18, 2.2, 2.22, 2.25, 2.28, 2.3, 2.32, 2.34, 2.36, 2.38, 2.4, 2.42, 2.44, 2.46, 2.48, 2.5, 2.52, 2.58, 2.6, or a range between any of the above values; more preferably, the relative viscosity is 2.21-2.38.

[0041] In a second aspect, the present application provides a preparation method of the long carbon chain polyamide resin composition according to the first aspect, comprising the following steps:

[0042] reacting the diamine, the diacid, and the phosphorus compound to obtain the long carbon chain polyamide resin composition.

[0043] Preferably, the material for the reaction further comprises at least one of a monobasic acid, an antioxidant, a catalyst, or a solvent.

[0044] In the present application, the catalyst comprises at least one of dibutyltin dilaurate, stannous octoate, or p-toluenesulfonic acid; the solvent comprises water; the mass of the solvent is 10-30% of the total mass of the reaction system; the total mass of the reaction system refers to the total mass of the diamine, the diacid, the phosphorus compound, and optionally the monobasic acid, the antioxidant, the catalyst, and the solvent.

[0045] Preferably, the reaction is performed in the presence of a protective atmosphere, which includes but is not limited to nitrogen.

[0046] Preferably, the reaction comprises: under stirring, heating to 190-210°C within 1-3 hours, then draining water to increase the reaction temperature to 260-310°C, and then performing vacuum extraction at 260-310°C for 1-3 hours to obtain the long carbon chain polyamide resin composition.

[0047] In the present application, the phosphorus compound can be added in the initial stage of the reaction or in the middle stage of the reaction when the phosphorus compound reacts with the diamine and the diacid; the reaction comprises: mixing the diamine, the diacid, the phosphorus compound, and optionally the monobasic acid, the antioxidant, the catalyst, and the solvent, heating to 190-210 DEG C in 1-3 hours in the presence of a protective atmosphere and under stirring, then draining to increase the reaction temperature to 260-310 DEG C, and then vacuumizing at a constant temperature of 260-310 DEG C for 1-3 hours to obtain the long carbon chain polyamide resin composition; or, the reaction comprises: mixing the diamine, the diacid, and optionally the monobasic acid, the antioxidant, the catalyst, and the solvent, heating to 190-210 DEG C in 1-3 hours in the presence of a protective atmosphere and under stirring, then draining to increase the reaction temperature to 260-310 DEG C, adding the phosphorus compound into the reaction, and then vacuumizing at a constant temperature of 260-310 DEG C for 1-3 hours to obtain the long carbon chain polyamide resin composition.

[0048] In a third aspect, the present application provides an application of the long carbon chain polyamide resin composition according to the first aspect in a high-temperature forming process.

[0049] In the present application, the high temperature refers to a temperature ≥ 200 DEG C.

[0050] The numerical range in the present application not only includes the point values listed above, but also includes any point values between the above numerical ranges which are not listed, and the present application does not list the specific point values included in the range for the sake of brevity and simplicity.

[0051] Compared with the prior art, the present application has the following beneficial effects:

[0052] The long carbon chain polyamide resin composition provided by the present application contains a specific content of phosphorus compound, so that the long carbon chain polyamide resin has good solvent resistance, a high proportion of smooth finished parts after forming, and good apparent quality of the product, and the long carbon chain polyamide resin composition also has good toughness, strength, and heat resistance. DETAILED DESCRIPTION

[0053] The technical solutions of the present application will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the present application and should not be regarded as specific limitations on the present application.

[0054] The materials used in the present application can be obtained by market purchase or conventional methods, and if not specifically stated, the materials used in the present application are as follows:

[0055] Terephthalic acid: purity > 99%, Anellotech Inc.

[0056] Dodecanedioic acid: purity > 99%, Shanghai Kaisai Biotechnology Co., Ltd.

[0057] Sebacic acid: purity > 99%, Wuxi Yinda Nylon Co., Ltd.

[0058] Pentanediamine: purity > 99%, Heilongjiang Ypin New Material Co., Ltd.

[0059] Sebacic diamine: purity > 99%, Wuxi Yinda Nylon Co., Ltd.

[0060] Hexamethylenediamine: purity 99%, China Chemical Tianchen Qixiang New Material Co., Ltd.

[0061] Phosphorus pentoxide: purity > 98%, Shanghai Aladdin Biochem Technology Co., Ltd.

[0062] Phosphorous acid: purity > 99%, Shanghai Aladdin Biochem Technology Co., Ltd.

[0063] Monopotassium phosphate: purity > 99%, Shanghai Aladdin Biochem Technology Co., Ltd.

[0064] Antioxidant 1098: Shuangjian Chemical Co., Ltd.

[0065] Examples 1-13 and Comparative Examples 1-5

[0066] Examples 1-13 and Comparative Examples 1-5 each provide a long carbon chain polyamide resin composition comprising a long carbon chain polyamide resin and a phosphorus compound; the specific composition is shown in Tables 1-3; in Tables 1-3, the phosphorus element content refers to the actual test content of phosphorus element in the long carbon chain polyamide resin composition; the addition amount of the phosphorus compound is the proportion of the phosphorus compound in the total mass of diamine, diacid and end-capping agent, and " / " indicates that the component is not in the formula; the composition of diamine structural units in the long carbon chain polyamide resin is shown in Tables 1-3, based on the total molar amount of diamine structural units being 100%; the composition of diacid structural units in the long carbon chain polyamide resin is shown in Tables 1-3, based on the total molar amount of diacid structural units being 100%.

[0067] The preparation method of the long carbon chain polyamide resin composition in the examples and comparative examples of the present application includes: adding diamine, diacid and end-capping agent (stearic acid, 1.5% of the total molar amount of diacid) into an autoclave; then adding phosphorus compound, antioxidant (antioxidant 1098, 0.1% of the mass of the obtained composition with the mass content of 100%), catalyst (stannous octoate, 0.1% of the total mass of the other materials except solvent) and deionized water (20% of the total mass of the reaction system) into the autoclave; vacuumizing and then filling high-purity nitrogen as protective gas, heating to 200℃ under stirring within 2h, then draining water under stirring and increasing the temperature of the reactants to 290℃; then vacuumizing at 290℃ for 2h, increasing the molecular weight of the polymer by removing the formed water, discharging after the reaction is completed, and obtaining the long carbon chain polyamide resin composition.

[0068] The preparation method of the long carbon chain polyamide resin composition provided in Example 13 includes: adding diamine, diacid and end-capping agent (stearic acid, 1.5% of the total molar amount of diacid) into an autoclave; then adding antioxidant (antioxidant 1098, 0.1% of the mass of the obtained composition with the mass content of 100%), catalyst (stannous octoate, 0.1% of the total mass of the other materials except solvent) and deionized water (20% of the total mass of the reaction system) into the autoclave; vacuumizing and then filling high-purity nitrogen as protective gas, heating to 200℃ under stirring within 2h, then draining water under stirring and increasing the temperature of the reactants to 290℃; then adding phosphorus compound into the autoclave, and then vacuumizing at 290℃ for 2h, increasing the molecular weight of the polymer by removing the formed water, discharging after the reaction is completed, and obtaining the long carbon chain polyamide resin composition.

[0069] In the present application, the testing method of the content of phosphorus element in the long carbon chain polyamide resin composition includes: taking 0.2g of the long carbon chain polyamide resin composition, adding 7mL of nitric acid, and digesting in a high-pressure tank at 200℃ for 2.5h; after the digestion program is completed, filtering after cooling and diluting to 50mL with pure water, and testing with an inductively coupled plasma atomic emission spectrometer (ICP-OES, manufacturer Thermo Scientific, model iCAP RQ).

[0070] In the present application, the molar content of diamine structural units and diacid structural units in the molecular structure of the long carbon chain polyamide resin can be tested by nuclear magnetic resonance carbon spectrum, and the specific method includes: dissolving 60mg of the long carbon chain polyamide resin composition sample in 0.5mL of hexafluoroisopropanol, adding 0.2mL of deuterated chloroform after dissolution, and then quantitatively determining with a Bruker AV500 nuclear magnetic resonance spectrometer 13C NMR, the molar ratio of the diamine to the diacid and the respective composition are determined by the integral area of the characteristic peaks of the diamine and the diacid.

[0071] Exemplarily, taking pentanediamine and decanediamine as examples, the characteristic peak positions of pentanediamine and decanediamine are known (which can be obtained by testing the diamine monomer or known according to the literature), wherein the integral area of the characteristic peak of pentanediamine is denoted as A1, and the integral area of the characteristic peak of decanediamine is denoted as A2, then the molar percentage content of pentanediamine in the diamine is A1 / (A1+A2) x 100%.

[0072] In the present application, the relative viscosity of the long carbon chain polyamide resin composition is tested according to the standard GB / T12006.1-2009, and the specific test method is as follows: the relative viscosity of the long carbon chain polyamide resin composition with a concentration of 1 g / dL is measured in 96% concentrated sulfuric acid at 25±0.01℃.

[0073] Table 1

[0074]

[0075] Table 2

[0076]

[0077]

[0078] Table 3

[0079]

[0080] Performance test

[0081] (1) Heat resistance: tested by using a TGA550 thermal analyzer, and the specific test method comprises: under a nitrogen atmosphere, the temperature is increased from 50℃ to 600℃ at a rate of 10℃ / min, the nitrogen purging speed is 60 mL / min, and the temperature at which the sample provided by the long carbon chain polyamide resin composition of Examples 1-13 and Comparative Examples 1-5 loses 5% of weight is denoted as T d5％ , the greater T d5％ , the better the heat resistance.

[0082] (2) Tensile strength and elongation at break: the tensile strength and elongation at break of the long carbon chain polyamide resin composition provided by Examples 1-13 and Comparative Examples 1-5 are tested according to the national standard GB / T 1040.1-2018, and the tensile rate is 10 mm / min.

[0083] (3) Solvent resistance: after the long-chain polyamide resin composition provided by Examples 1-13 and Comparative Examples 1-5 was immersed in a cooling liquid medium at 120°C for 2000h, the elongation at break of the long-chain polyamide resin composition was tested, and the elongation at break retention rate was calculated; elongation at break retention rate = elongation at break after aging / elongation at break before aging x 100%; the higher the elongation at break retention rate, the better the solvent resistance; wherein the cooling liquid medium was prepared by mixing ethylene glycol and water at a volume ratio of 1:1, and the cooling liquid medium could be supplemented during the aging process to ensure that the long-chain polyamide resin composition was immersed in the cooling liquid medium.

[0084] (4) Smooth part ratio: the long-chain polyamide resin composition was injection molded into a 5mm x 5mm x 1mm square plate at a temperature 20°C above the melting point; 100 parts were prepared in parallel, and the surface of the parts was observed with the naked eye to determine whether there were pits. The number of parts with pits was calculated as B%, and the smooth part ratio was 100%-B%; wherein the melting point of the composition could be tested by a differential scanning calorimeter.

[0085] The specific test results are shown in Table 4.

[0086] Table 4

[0087]

[0088]

[0089] As can be seen from Table 4, the long-chain polyamide resin composition provided by the present application includes a specific content of phosphorus compounds, so that the long-chain polyamide resin has good solvent resistance, a high proportion of smooth parts after molding, and good apparent quality of the product. In addition, the long-chain polyamide resin composition also has good toughness, strength and heat resistance; the long-chain polyamide resin composition has a T d5％ ≥396°C, tensile strength ≥50MPa, elongation at break ≥112%, elongation at break retention rate ≥80%, and smooth part ratio ≥90%.

[0090] As can be seen from Comparative Examples 1, 2 and 4, the content of phosphorus compounds in the long-chain polyamide resin composition is too high, and the heat resistance is very poor; too little or even none, and the toughness, solvent resistance and smooth part ratio are low; wherein the content of phosphorus element in Comparative Example 4 was detected to be 0.8ppm, which was speculated to be caused by pollution of the instruments and devices used for reaction or detection.

[0091] As can be seen from Comparative Example 3, the content of aromatic diacid structural units in the long-chain polyamide resin composition is too high, and the toughness is very poor, and the solvent resistance and smooth part ratio are also reduced.

[0092] As can be seen from Comparative Example 5, the aliphatic dibasic acid carbon chain in the long carbon chain polyamide resin composition is too short, the toughness is poor, the solvent resistance and the proportion of smooth finished parts are also reduced.

[0093] The above-described specific examples further detail the purposes, technical solutions and beneficial effects of the present application. It should be understood that the above-described specific examples are merely specific embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A long carbon chain polyamide resin composition, characterized by, The long carbon chain polyamide resin composition comprises a long carbon chain polyamide resin and a phosphorus compound; The long carbon chain polyamide resin composition comprises a long carbon chain polyamide resin and a phosphorus compound; The phosphorus compound is an oxide of phosphorus; The molecular structure of the long carbon chain polyamide resin comprises a diacid structural unit and a diamine structural unit; The diacid structural unit comprises an aromatic diacid structural unit and a long carbon chain aliphatic diacid structural unit; the molar percentage content of the aromatic diacid structural unit in the diacid structural unit is less than 70%; The long carbon chain aliphatic diacid structural unit has a main chain carbon atom number greater than 6; The long carbon chain polyamide resin composition is prepared by a preparation method comprising the following steps: The diamine, the diacid, and the phosphorus compound are reacted to obtain the long carbon chain polyamide resin composition.

2. The long carbon chain polyamide resin composition according to claim 1, characterized by, The long carbon chain polyamide resin composition comprises a long carbon chain polyamide resin and a phosphorus compound; 3. The long carbon chain polyamide resin composition according to claim 1, characterized by, The oxide of phosphorus comprises diphosphorus pentoxide and / or diphosphorus trioxide.

4. The long carbon chain polyamide resin composition according to claim 1, characterized by, The molar percentage content of the aromatic diacid structural unit in the diacid structural unit is 10-66%.

5. The long carbon chain polyamide resin composition according to claim 4, characterized by The molar percentage content of the aromatic diacid structural unit in the diacid structural unit is 20-60%.

6. The long carbon chain polyamide resin composition according to claim 1, characterized by, The aromatic diacid structural unit comprises a terephthalic acid structural unit.

7. The long carbon chain polyamide resin composition according to claim 1, wherein The long carbon chain aliphatic diacid structural unit has a main chain carbon atom number greater than 6.

8. The long carbon chain polyamide resin composition according to claim 1, characterized by, The long carbon chain aliphatic diacid structural unit comprises at least one of azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, or tetradecanedioic acid.

9. The long carbon chain polyamide resin composition according to claim 1, characterized by, The diamine structural unit has a main chain carbon atom number greater than or equal to 4.

10. The long carbon chain polyamide resin composition according to claim 1, characterized by, The diamine structural unit comprises at least one of butanediamine, pentanediamine, hexanediamine, or decanediamine.

11. The long carbon chain polyamide resin composition according to claim 1, characterized by, The molecular structure of the long carbon chain polyamide resin further comprises a diamine structural unit capped by a monobasic acid.

12. The long carbon chain polyamide resin composition according to claim 11, characterized by The molar percentage content of the monobasic acid-capped diamine structural unit is 1-6% of the diacid structural unit.

13. The long carbon chain polyamide resin composition according to claim 12, characterized by The monobasic acid comprises at least one of stearic acid, benzoic acid, acetic acid, lauric acid, or cyclohexanecarboxylic acid.

14. The long carbon chain polyamide resin composition according to claim 1, characterized by, The long carbon chain polyamide resin composition further comprises an antioxidant.

15. The long carbon chain polyamide resin composition according to claim 14, characterized by The mass content of the antioxidant in the long carbon chain polyamide resin composition is 0.05-0.3%.

16. The long carbon chain polyamide resin composition according to claim 1, characterized by, The relative viscosity of the long carbon chain polyamide resin composition is 1.8-2.

6.

17. The long carbon chain polyamide resin composition according to claim 16, characterized by The relative viscosity of the long carbon chain polyamide resin composition is 2.21-2.

38.

18. A process for producing the long-chain polyamide resin composition according to any one of claims 1 to 17, characterized by, The preparation method comprises the following steps: The diamine, the diacid, and the phosphorus compound are reacted to obtain the long carbon chain polyamide resin composition.

19. The method of claim 18, wherein, The reaction material further comprises at least one of a monobasic acid, an antioxidant, a catalyst, or a solvent.

20. The method of claim 18, wherein, The reaction is carried out in the presence of a protective atmosphere.

21. The method of claim 18, wherein, The reaction comprises the following steps: under stirring, the temperature is raised to 190-210°C within 1-3 hours, then water is drained to raise the reaction temperature to 260-310°C, and then vacuum reaction is carried out at 260-310°C for 1-3 hours to obtain the long carbon chain polyamide resin composition.

22. Use of the long chain polyamide resin composition according to any one of claims 1 to 17 in a high temperature molding process.

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