Long-carbon-chain polyamide resin composition as well as preparation method and application thereof

Abstract

The invention provides a long carbon chain polyamide resin composition. The long carbon chain polyamide resin composition comprises long carbon chain polyamide resin and a phosphorus compound, the content of the 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 binary acid structural unit and a diamine structural unit; the binary acid structural unit comprises an aromatic binary acid structural unit and a long carbon chain aliphatic binary acid structural unit; the molar percentage content of the aromatic dibasic acid structural unit in the dibasic acid structural unit is less than 70%. According to the present invention, the long carbon chain polyamide resin composition has characteristics of high bright and clean product ratio, excellent solvent resistance, good toughness, good strength and good heat resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of engineering plastics, and specifically relates to a long carbon chain polyamide resin composition and a preparation method and application thereof. Background Art

[0002] Long-chain polyamide refers to at least one monomer with ≥10 carbon atoms in the main chain polymerized with other monomers, such as PA1010, PA1012, PA12, etc. Compared with ordinary polyamide, long-chain polyamide has a low amide group density, good dimensional stability, excellent wear resistance and electrical properties, and long-chain polyamide resin has good toughness and softness, and high resilience; in addition, long-chain polyamide resin has low water absorption, so even in a humid environment, it can maintain good toughness, hardness and electrical properties. These excellent properties make long-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 resins, processes such as injection molding and extrusion molding are required. However, both injection molding and extrusion molding need to be carried out at relatively high temperatures. However, the heat resistance of long-chain polyamide resins is poor, which leads to insufficient performance of polyamide products after molding. In addition, the strength and solvent resistance of long-chain polyamide resins are poor, which also affects the further application of molded products in the field of chemical medium contact materials. Therefore, in order to improve the heat resistance, strength and solvent resistance of long-chain polyamide resins, 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 products; and due to differences in reaction activity, the introduction of rigid structures generally forms longer semi-aromatic sequences, and longer semi-aromatic sequences will also affect the solvent resistance of long-chain polyamides; in addition, the introduction of rigid structures will cause the toughness of long-chain polyamides to deteriorate.

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

[0005] In view of the shortcomings of the prior art, the present invention aims to provide a long carbon chain polyamide resin composition and a preparation method and application thereof. The long carbon chain polyamide resin composition has a high proportion of smooth parts and excellent solvent resistance, and at the same time, can have good toughness, strength and heat resistance.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In the first aspect, the present invention provides a long-chain polyamide resin composition, which includes a long-chain polyamide resin and a phosphorus compound; the phosphorus content in the long-chain polyamide resin composition is 50 to 350 ppm; the molecular structure of the long-chain polyamide resin includes a dibasic acid structural unit and a diamine structural unit; the dibasic acid structural unit includes an aromatic dibasic acid structural unit and a long-chain aliphatic dibasic acid structural unit; the molar percentage of the aromatic dibasic acid structural unit in the dibasic acid structural unit is less than 70%; the number of main chain carbon atoms in the long-chain aliphatic dibasic acid structural unit is greater than 6.

[0008] In the present invention, the long-chain polyamide resin composition includes a specific content of phosphorus compounds (the content of the phosphorus compounds is determined by the phosphorus element content), so that the long-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 product appearance quality is good.

[0009] In the present invention, the phosphorus content in the long carbon chain polyamide resin composition is 50 to 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 0ppm, 135ppm, 140ppm, 145ppm, 150ppm, 155ppm, 160ppm, 165ppm, 170ppm, 175ppm, 180ppm, 185ppm, 190ppm, 195ppm, 200ppm, 205ppm, 210ppm, 215ppm, 220ppm, 225ppm, 230ppm, 235ppm, 240ppm, 245ppm, 250ppm, 255ppm, 260ppm, 265ppm, 270ppm, 275ppm, 280ppm, 285ppm, 290ppm, 300ppm, 310ppm, 320ppm, 330ppm, 340ppm, 350ppm or a range between any of the above values.

[0010] In the present invention, the mechanism of action of the phosphorus compound is not yet clear, but it is speculated as follows: phosphorus element can regulate the sequence of aromatic dibasic acid and aliphatic dibasic acid in the long carbon chain polyamide resin, so that the aromatic dibasic acid sequence is shorter and randomly distributed in the polyamide molecular chain, which is beneficial to improve the toughness and solvent resistance of the long carbon chain polyamide resin composition and ensure a high proportion of smooth parts; low phosphorus content, more by-products and impurities in the long carbon chain polyamide resin composition, resulting in a low proportion of smooth parts; and low phosphorus content may affect the reaction activity of aromatic dibasic acid and aliphatic dibasic acid in the dibasic acid combination, resulting in a long sequence of aromatic dibasic acid, and then resulting in poor toughness and solvent resistance of the long carbon chain polyamide resin composition; high phosphorus content will cause the long carbon chain polyamide resin composition to be easily decomposed during high temperature molding, and then result in poor thermal stability of the product.

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

[0012] In the present invention, the phosphorus compound only needs to contain phosphorus in its molecular structure, and there is no particular limitation on the source of phosphorus and the type of phosphorus compound added; the phosphorus compound can be added during the synthesis of the polyamide resin or after the synthesis of the polyamide resin.

[0013] Preferably, the phosphorus compound comprises at least one of a 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, and 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 ions; R 11 , R 12 , R 13 Each is independently selected from any one of an alkyl group, a cycloalkyl group or an aryl group.

[0016] In the present invention, the number of carbon atoms in the alkyl group is 1 to 10, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or any range therebetween; more preferably, the number of carbon atoms is 1 to 6.

[0017] In the present invention, the number of carbon atoms in the cycloalkyl group is 3 to 8, for example, 3, 4, 5, 6, 7, 8 or any range between the above values; more preferably, the number of carbon atoms is 3 to 6.

[0018] In the present invention, the number of carbon atoms in the alkoxy group is 1 to 10, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or any range therebetween; more preferably, the number of carbon atoms is 1 to 6.

[0019] In the present invention, the number of carbon atoms in the aromatic group is 6 to 20, for example, 6, 8, 10, 12, 14, 16, 18, 20 or any range between the above values; more preferably, the number of carbon atoms is 6 to 15.

[0020] In the present invention, the metal ions include but are not limited to sodium ions, potassium ions, calcium ions, magnesium ions, lithium ions, zinc ions, and the like.

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

[0022] Preferably, the phosphorus compound having the structure shown in Formula I includes at least one of phosphoric acid, phosphorous acid, hypophosphorous acid, phosphate ester compounds, phosphorous acid diesters, phosphate compounds, phosphite compounds or hypophosphite compounds.

[0023] Preferably, the phosphorus compound having the structure shown in Formula II comprises a triester phosphite compound.

[0024] In the present invention, the phosphate ester compounds include but are not limited to triphenyl phosphate, trimethyl phosphate, triethyl phosphate, cyclohexyl dimethyl phosphate, etc.; the phosphite diesters include but are not limited to dimethyl phosphite, diethyl phosphite, diphenyl phosphite, etc.; the phosphate compounds include but are not limited to potassium dihydrogen phosphate, potassium phosphate, dipotassium hydrogen phosphate, sodium dihydrogen phosphate, sodium phosphate, disodium hydrogen phosphate; the phosphites include but are not limited to sodium phosphite, etc.; the hypophosphites include but are not limited to sodium hypophosphite, etc.

[0025] In the present invention, water is generated in the process of generating polyamide by the reaction of diamine and dibasic acid, and the amount of water generated varies according to the type and ratio of the monomers. In the reaction process, water needs to be discharged under high pressure, but different phosphorus compounds have different binding forces with water, and a small amount of phosphorus compounds or their derivatives will be discharged during the high-pressure drainage process. Therefore, the phosphorus content of the products obtained by different phosphorus compounds under the same formula and process will have certain differences, and therefore, the phosphorus content in the long-chain polyamide resin composition is affected by the amount of phosphorus compound added, the type of monomer and the ratio.

[0026] In the present invention, the phosphorus content in the long-chain polyamide resin composition (ppm) = (mass of phosphorus in the added phosphorus compound - mass of phosphorus in the lost phosphorus compound) / (mass of diamine + mass of dibasic acid + mass of monobasic acid end-capping agent - mass of discharged water). It should be noted that there may be more or less differences between the theoretical phosphorus content and the actually detected phosphorus content, such as the phosphorus content is also affected by the contamination of raw materials during production, storage and transportation, and the contamination of production equipment during the synthesis of polyamide resin. Therefore, the phosphorus content in the present invention is the phosphorus content actually detected in the long-chain polyamide resin composition.

[0027] Preferably, the molar percentage of the aromatic dibasic acid structural unit in the dibasic acid 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 the range between any of the above values; more preferably, the molar percentage of the aromatic dibasic acid structural unit is 20-60%.

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

[0029] Preferably, the number of main chain carbon atoms in the long carbon chain aliphatic dibasic acid 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 the above values, and more preferably, the number of main chain carbon atoms in the long carbon chain aliphatic dibasic acid structural unit is 10-15.

[0030] Preferably, the long carbon chain aliphatic dibasic acid structural unit includes at least one of azelaic acid structural unit, a sebacic acid structural unit, an undecanedioic acid structural unit, a dodecanedioic acid structural unit or a 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 any range therebetween, more preferably, the number of main chain carbon atoms in the diamine structural unit is 4-10.

[0032] Preferably, the diamine structural unit includes at least one of a butanediamine structural unit, a pentanediamine structural unit, a hexamethylenediamine structural unit or a decanediamine structural unit.

[0033] In the present invention, in the long carbon chain polyamide resin, the molar ratio of the dibasic acid structural unit to the diamine structural unit is (0.8-1.2):1, wherein the specific value in (0.8-1.2) can be, for example, 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 molecular structure of the long carbon chain polyamide resin further includes a diamine structural unit terminated by a monobasic acid.

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

[0036] Preferably, the monoacid includes at least one of stearic acid, benzoic acid, acetic acid, lauric acid or cyclohexanecarboxylic 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 any range between the above values.

[0039] In the present invention, the antioxidant includes but is not limited to at least one of N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexanediamine (antioxidant 1098), pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (antioxidant 1010), tris[2.4-di-tert-butylphenyl]phosphite (antioxidant 168), and β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (antioxidant 1076).

[0040] Preferably, the relative viscosity of the long carbon chain polyamide resin composition is 1.8 to 2.6, for example, it can be 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 the range between any of the above values; more preferably, the relative viscosity is 2.21 to 2.38.

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

[0042] The diamine, the dibasic acid and the phosphorus compound are reacted to obtain the long carbon chain polyamide resin composition.

[0043] Preferably, the reaction materials further include at least one of a monoacid, an antioxidant, a catalyst or a solvent.

[0044] In the present invention, the catalyst includes at least one of dibutyltin dilaurate, stannous octoate or p-toluenesulfonic acid; the solvent includes 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, dibasic acid, phosphorus compound and optional monobasic acid, antioxidant, catalyst and solvent.

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

[0046] Preferably, the reaction comprises: raising the temperature to 190-210° C. within 1-3 hours under stirring conditions, then draining the water to raise the reaction temperature to 260-310° C., and then conducting a constant temperature vacuum reaction at 260-310° C. for 1-3 hours to obtain the long-chain polyamide resin composition.

[0047] In the present invention, when the phosphorus compound reacts with the diamine and the dibasic acid, the phosphorus compound can be added in the initial stage of the reaction or in the middle stage of the reaction; the reaction comprises: mixing the diamine, the dibasic acid, the phosphorus compound and the optional monobasic acid, the antioxidant, the catalyst and the solvent, heating the mixture to 190 to 210° C. within 1 to 3 hours under the condition of protective atmosphere and stirring, then draining the mixture to raise the reaction temperature to 260 to 310° C., and then conducting the reaction at 260 to 310° C. under constant temperature and vacuuming for 1 h. ~3h, to obtain the long carbon chain polyamide resin composition; or, the reaction includes: mixing a diamine, a dibasic acid and an optional monobasic acid, an antioxidant, a catalyst, and a solvent, heating to 190-210°C within 1-3h in the presence of a protective atmosphere and under stirring conditions, then draining water to increase the reaction temperature to 260-310°C, adding a phosphorus compound thereto, and then reacting at a constant temperature of 260-310°C under vacuum for 1-3h to obtain the long carbon chain polyamide resin composition.

[0048] In a third aspect, the present invention provides a use of the long carbon chain polyamide resin composition according to the first aspect in a high temperature molding process.

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

[0050] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

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

[0052] The long-chain polyamide resin composition provided by the present invention comprises 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 surface quality of the products. At the same time, the long-chain polyamide resin composition also has good toughness, strength and heat resistance. DETAILED DESCRIPTION

[0053] The technical solution of the present invention is further described below by specific implementation methods. 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.

[0054] The materials used in the present invention can be obtained by commercially available or conventional methods. Unless otherwise specified, the materials used in the present invention are as follows:

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

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

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

[0058] Pentamethylenediamine: purity>99%, Heilongjiang Yipin New Materials Co., Ltd.

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

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

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

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

[0063] Potassium dihydrogen phosphate: purity>99%, Shanghai Aladdin Biochemical Technology Co., Ltd.

[0064] Antioxidant 1098: Double Bond Chemical Company.

[0065] Examples 1 to 13, Comparative Examples 1 to 5

[0066] Embodiments 1 to 13 and comparative examples 1 to 5 respectively provide a long-chain polyamide resin composition, comprising a long-chain polyamide resin and a phosphorus compound; the specific composition is shown in Tables 1 to 3; wherein, in Tables 1 to 3, the phosphorus content refers to the phosphorus content in the long-chain polyamide resin composition obtained by actual testing; the amount of the phosphorus compound added is the proportion of the phosphorus compound in the total mass of the diamine, the dibasic acid and the end-capping agent, and " / " indicates that the component is not included in the formula; taking the total molar amount of the diamine structural unit as 100%, the composition of the diamine structural unit in the long-chain polyamide resin is shown in Tables 1 to 3; taking the total molar amount of the dibasic acid structural unit as 100%, the composition of the dibasic acid structural unit in the long-chain polyamide resin is shown in Tables 1 to 3.

[0067] Unless otherwise specified, the preparation method of the long-chain polyamide resin composition described in the embodiments of the present invention and the comparative examples comprises: adding a diamine, a dibasic acid and a capping agent (stearic acid, the molar amount is 1.5% of the total molar amount of the dibasic acid) into a pressure autoclave; then adding a phosphorus compound, an antioxidant (antioxidant 1098, based on the mass content of the obtained composition being 100%, the mass of the antioxidant is 0.1%), a catalyst (stannous octoate, the mass is 0.1% of the total mass of other materials except the solvent) and deionized water (the mass is 20% of the total mass of the reaction system); after evacuating, high-purity nitrogen is filled as a protective gas, the temperature is raised to 200° C. within 2 hours under stirring conditions, and then the reactants are drained and the temperature is raised to 290° C. under stirring; then the reaction is carried out at a constant temperature of 290° C. for 2 hours to increase the molecular weight of the polymer by removing the formed water, and the reaction is discharged after the reaction is completed to obtain the long-chain polyamide resin composition.

[0068] Among them, the preparation method of the long carbon chain polyamide resin composition provided in Example 13 includes: adding a diamine, a dibasic acid and a capping agent (stearic acid, the molar amount is 1.5% of the total molar amount of the dibasic acid) into a pressure autoclave; then adding an antioxidant (antioxidant 1098, based on the mass content of the obtained composition being 100%, the mass of the antioxidant is 0.1%), a catalyst (stannous octoate, the mass is 0.1% of the total mass of other feed materials excluding the solvent) and deionized water (the mass is 20% of the total mass of the reaction system); after vacuuming, filling with high-purity nitrogen as a protective gas, heating to 200°C within 2 hours under stirring conditions, then draining water under stirring and raising the temperature of the reactants to 290°C; then adding a phosphorus compound thereto, and then vacuuming the reaction at a constant temperature of 290°C for 2 hours, increasing the molecular weight of the polymer by removing the formed water, and discharging the material after the reaction is completed to obtain the long carbon chain polyamide resin composition.

[0069] In the present invention, the testing method for the phosphorus content in the long-chain polyamide resin composition comprises: weighing 0.2 g of the long-chain polyamide resin composition, adding 7 mL of nitric acid, digesting in a high-pressure tank at 200° C. for 2.5 h, cooling and filtering after the digestion procedure, adding pure water to make the volume to 50 mL, and testing with an inductively coupled plasma atomic emission spectrometer (ICP-OES, manufacturer Thermo Scientific, model iCAP RQ).

[0070] In the present invention, the molar content of the diamine structural unit and the dibasic acid structural unit in the molecular structure of the long carbon chain polyamide resin can be tested by nuclear magnetic resonance carbon spectroscopy. The specific method includes: taking 60 mg of the long carbon chain polyamide resin composition sample and dissolving it in 0.5 mL of hexafluoroisopropanol, adding 0.2 mL of deuterated chloroform after dissolution, and then using Bruker AV500 nuclear magnetic resonance spectrometer to quantitatively determine 13C NMR, the molar ratio of diamine to dibasic acid and their respective compositions were determined by the integrated areas of the characteristic peaks of diamine and dibasic acid.

[0071] For example, taking the diamines pentamethylenediamine and decamethylenediamine as examples, the characteristic peak positions of pentamethylenediamine and decamethylenediamine are known (which can be obtained by testing the diamine monomers or known from the literature), wherein the integral area of ​​the characteristic peak of pentamethylenediamine is denoted as A1, and the integral area of ​​the characteristic peak of decamethylenediamine is denoted as A2, then the molar percentage content of pentamethylenediamine in the diamine is A1 / (A1+A2)×100%.

[0072] In the present invention, the relative viscosity of the long-chain polyamide resin composition is measured according to the standard GB / T12006.1-2009. The specific test method is: measuring the relative viscosity of the long-chain polyamide resin composition with a concentration of 1 g / dL in 96% concentrated sulfuric acid at 25±0.01°C.

[0073] Table 1

[0074]

[0075] Table 2

[0076]

[0077]

[0078] Table 3

[0079]

[0080] Performance Testing

[0081] (1) Heat resistance: The test was conducted using a U.S. TGA550 thermal analyzer. The specific test method includes: in a nitrogen atmosphere, the temperature was raised from 50°C to 600°C at a heating rate of 10°C / min and a nitrogen purge rate of 60 mL / min. The temperature at which the long-chain polyamide resin composition samples provided in Examples 1 to 13 and Comparative Examples 1 to 5 lost 5% of their weight was measured, and recorded as T d5％ , T d5％ The larger it is, the better the heat resistance is.

[0082] (2) Tensile strength and elongation at break: The tensile strength and elongation at break of the long carbon chain polyamide resin compositions provided in Examples 1 to 13 and Comparative Examples 1 to 5 were tested in accordance with the national standard GB / T 1040.1-2018, with a tensile rate of 10 mm / min.

[0083] (3) Solvent resistance: After the long-chain polyamide resin compositions provided in Examples 1 to 13 and Comparative Examples 1 to 5 were immersed in a coolant medium at 120° C. and aged for 2000 h, the elongation at break of the long-chain polyamide resin compositions 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 × 100%; the higher the elongation at break retention rate, the better the solvent resistance, wherein the coolant medium is prepared by mixing ethylene glycol and water in a volume ratio of 1:1. During the aging process, the coolant medium can be supplemented to ensure that the coolant medium immerses the long-chain polyamide resin composition.

[0084] (4) Smooth parts ratio: The long carbon chain polyamide resin composition is injection molded into a 5mm×5mm×1mm square plate at a temperature 20°C above the melting point; 100 parts are prepared in parallel, and the surface of the parts is observed with the naked eye to see if there are pitting. The number of parts with pitting is calculated as B%, and the smooth parts ratio is 100%-B%; wherein, the melting point of the composition can be tested by differential scanning calorimetry.

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

[0086] Table 4

[0087]

[0088]

[0089] As shown in Table 4, the long-chain polyamide resin composition provided by the present invention 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 product appearance quality. At the same time, the long-chain polyamide resin composition also has good toughness, strength and heat resistance; the T d5％ ≥396℃, tensile strength ≥50MPa, elongation at break ≥112%, elongation at break retention rate ≥80%, proportion of smooth parts ≥90%.

[0090] It can be seen from Comparative Examples 1, 2, and 4 that if the content of phosphorus compounds in the long-chain polyamide resin composition is too high, the heat resistance is extremely poor; if it is too little or even absent, the toughness and solvent resistance are poor, and the proportion of smooth parts is low; among them, the phosphorus content detected in Comparative Example 4 is 0.8 ppm, which is presumably caused by contamination of instruments and devices used in the reaction or detection.

[0091] It can be seen from Comparative Example 3 that the content of aromatic dibasic acid structural units in the long carbon chain polyamide resin composition is too high, the toughness is extremely poor, and the solvent resistance and the proportion of smooth parts are also reduced.

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

[0093] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A long carbon chain polyamide resin composition, characterized in that: The long carbon chain polyamide resin composition comprises a long carbon chain polyamide resin and a phosphorus compound; The phosphorus content in the long carbon chain polyamide resin composition is 50 to 350 ppm; The molecular structure of the long carbon chain polyamide resin includes a dibasic acid structural unit and a diamine structural unit; The dibasic acid structural unit comprises an aromatic dibasic acid structural unit and a long carbon chain aliphatic dibasic acid structural unit; the molar percentage of the aromatic dibasic acid structural unit in the dibasic acid structural unit is less than 70%; The number of main chain carbon atoms in the long carbon chain aliphatic dibasic acid structural unit is greater than 6.

2. The long carbon chain polyamide resin composition according to claim 1, characterized in that: The phosphorus content in the long carbon chain polyamide resin composition is 105-320 ppm.

3. The long carbon chain polyamide resin composition according to claim 1 or 2, characterized in that: The phosphorus compound includes at least one of a phosphorus oxide, a phosphorus compound having a structure shown in Formula I, or a phosphorus compound having a structure shown in Formula II; Wherein, R1, R2, and 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 ions; R 11 , R 12 , R 13 Each is independently selected from any one of an alkyl group, a cycloalkyl group or an aryl group; Preferably, the phosphorus oxide comprises phosphorus pentoxide and / or phosphorus trioxide; Preferably, the phosphorus compound having the structure shown in Formula I comprises at least one of phosphoric acid, phosphorous acid, hypophosphorous acid, phosphate ester compounds, phosphorous acid diesters, phosphate compounds, phosphite compounds or hypophosphite compounds; Preferably, the phosphorus compound having the structure shown in Formula II comprises a triester phosphite compound.

4. The long carbon chain polyamide resin composition according to any one of claims 1 to 3, characterized in that: The molar percentage of the aromatic dibasic acid structural unit in the dibasic acid structural unit is 10 to 66%, and more preferably the molar percentage of the aromatic dibasic acid structural unit is 20 to 60%; Preferably, the aromatic dibasic acid structural unit comprises a terephthalic acid structural unit.

5. The long carbon chain polyamide resin composition according to any one of claims 1 to 4, characterized in that: The number of main chain carbon atoms in the long carbon chain aliphatic dibasic acid structural unit is ≥ 8; Preferably, the long carbon chain aliphatic dibasic acid structural unit comprises at least one of azelaic acid structural unit, a sebacic acid structural unit, an undecanedioic acid structural unit, a dodecanedioic acid structural unit or a tetradecanedioic acid structural unit; Preferably, the number of main chain carbon atoms in the diamine structural unit is ≥4; Preferably, the diamine structural unit includes at least one of a butanediamine structural unit, a pentanediamine structural unit, a hexamethylenediamine structural unit or a decanediamine structural unit.

6. The long carbon chain polyamide resin composition according to any one of claims 1 to 5, characterized in that: The molecular structure of the long carbon chain polyamide resin also includes a diamine structural unit terminated by a monobasic acid; Preferably, the molar percentage of the monoacid-terminated diamine structural unit is 1 to 6% of the diacid structural unit; Preferably, the monoacid includes at least one of stearic acid, benzoic acid, acetic acid, lauric acid or cyclohexanecarboxylic acid.

7. The long carbon chain polyamide resin composition according to any one of claims 1 to 6, characterized in that: The long carbon chain polyamide resin composition also includes an antioxidant; Preferably, the mass content of the antioxidant in the long carbon chain polyamide resin composition is 0.05-0.3%; Preferably, the relative viscosity of the long carbon chain polyamide resin composition is 1.8 to 2.6, and more preferably the relative viscosity is 2.21 to 2.

38.

8. A method for preparing the long carbon chain polyamide resin composition according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: The diamine, the dibasic acid and the phosphorus compound are reacted to obtain the long carbon chain polyamide resin composition.

9. The preparation method according to claim 8, characterized in that: The reaction materials also include at least one of a monoacid, an antioxidant, a catalyst or a solvent; Preferably, the reaction is carried out in the presence of a protective atmosphere; Preferably, the reaction comprises: raising the temperature to 190-210° C. within 1-3 hours under stirring conditions, then draining the water to raise the reaction temperature to 260-310° C., and then conducting a constant temperature vacuum reaction at 260-310° C. for 1-3 hours to obtain the long-chain polyamide resin composition.

10. Use of the long carbon chain polyamide resin composition according to any one of claims 1 to 7 in a high temperature molding process.

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