Pa compositions, methods of making, and molded articles

Abstract

The application discloses a PA composition, a preparation method thereof and a molded part, and belongs to the technical field of polymer materials. The PA resin is added with specific amounts of a dihydrocarbyl-substituted phosphinic acid salt, a monohydrocarbyl-substituted phosphinic acid salt, a bromine-based flame retardant and a specific lubricant, so that the material has good flame retardance and a low surface friction coefficient, and is suitable for application in the fields of automobiles, electronic and electrical appliances and mechanical industry.

Description

Technical Field

[0001] This application relates to the field of polymer materials technology, specifically to PA compositions, their preparation methods, and molded parts. Background Technology

[0002] Polyamide (PA), with its excellent wear resistance and high mechanical strength, is often used as a functional component in mechanical and electrical equipment, such as gears and bearing housings. Under continuous operation, these components must withstand alternating loads and contact friction for extended periods. Excessive surface friction can easily lead to problems such as excessive operating noise and accelerated component wear, reducing operational stability and accuracy, and significantly shortening component lifespan. Therefore, it is crucial to further reduce the surface friction coefficient of polyamide materials through modification. Meanwhile, the inherent flammability of polyamide has become a key bottleneck restricting its wider application. How to simultaneously reduce the surface friction coefficient and improve the flame retardant properties of polyamide materials is of significant research value for expanding its applications. Summary of the Invention

[0003] Based on the deficiencies of the existing technology, the purpose of this application is to provide a PA composition, its preparation method and molded parts, wherein the PA composition has both good flame retardancy and low surface friction coefficient.

[0004] To achieve the above objectives, in a first aspect, this application provides a PA composition comprising the following components in parts by weight: 50-78.5 parts of PA resin, 3-12 parts of dialkyl-substituted phosphinate, 0.3-3 parts of monoalkyl-substituted phosphinate, 10-25 parts of brominated flame retardant, and 3-15 parts of lubricant. The dialkyl-substituted phosphonate is at least one of the compounds of formula I, and the monoalkyl-substituted phosphonate is at least one of the compounds of formula II. , Among them, R 1 R 2 and R 3 Each group is independently selected from the following groups: C1-C8 straight-chain alkyl, C3-C8 branched alkyl, C3-C8 cycloalkyl, C7-C8 aralkyl, and aryl groups. X and Y are each independently selected from Al, Mg, Ca, Zn, Ti, or Fe. n and m are each independently selected from integers between 2 and 4; The lubricant is selected from at least one of polyethylene wax, stearate, and polydimethylsiloxane.

[0005] Adding specific amounts of dialkyl-substituted hypophosphite, monoalkyl-substituted hypophosphite, brominated flame retardant, and specific lubricant to PA resin can give the material both good flame retardancy and a low coefficient of surface friction.

[0006] The PA resin is present in an amount of 50 to 78.5 parts by weight, such as 50 parts by weight, 52 parts by weight, 55 parts by weight, 58 parts by weight, 60 parts by weight, 62 parts by weight, 65 parts by weight, 68 parts by weight, 70 parts by weight, 72 parts by weight, 75 parts by weight, 78.5 parts by weight, or any two of these ranges. Preferably, the PA in the PA composition accounts for more than 45% by weight, such as 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or any two of these ranges.

[0007] The dialkyl-substituted phosphonate is 3 to 12 parts by weight, such as 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, 10 parts by weight, 11 parts by weight, 12 parts by weight, or any two of the above ranges.

[0008] The monoalkyl-substituted phosphonate is 0.3 to 3 parts by weight, such as 0.3 parts by weight, 0.5 parts by weight, 0.7 parts by weight, 1 part by weight, 1.2 parts by weight, 1.4 parts by weight, 1.6 parts by weight, 1.8 parts by weight, 2 parts by weight, 2.2 parts by weight, 2.4 parts by weight, 2.6 parts by weight, 2.8 parts by weight, 3 parts by weight, or any two of the above ranges.

[0009] The brominated flame retardant is 10 to 25 parts by weight, such as 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight, 20 parts by weight, 21 parts by weight, 22 parts by weight, 23 parts by weight, 24 parts by weight, 25 parts by weight, or any two of the above ranges.

[0010] The lubricant is 3 to 15 parts by weight, such as 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, or any two of the above ranges.

[0011] In some embodiments, the polyethylene wax is oxidized polyethylene wax with an acid value ranging from 0 to 80 mg KOH / g and a number-average molecular weight ranging from 1500 to 5000 g / mol.

[0012] The acid value of the polyethylene wax was determined by the following method: acid-base titration was used according to GB / T 2895-2008 standard.

[0013] The number-average molecular weight of the polyethylene wax was determined by gel permeation chromatography (GPC).

[0014] In some embodiments, the stearate is pentaerythritol stearate with a saponification value ranging from 120 to 160 mg KOH / g.

[0015] The saponification value of the stearate was determined by the following method: The saponification value was determined using a saponification reaction. Specifically, the stearate sample was heated and hydrolyzed under alkaline conditions to produce stearate and alcohol. By measuring the difference in excess alkali solution before and after the reaction, the amount of alkali consumed by the sample could be calculated, thus obtaining the saponification value.

[0016] In some embodiments, the polydimethylsiloxane has a viscosity range of 10 to 2,000,000 cSt at 25°C and a number-average molecular weight range of 1,000 to 500,000 g / mol.

[0017] The viscosity of the polydimethylsiloxane at 25°C was measured as follows: using the Ubbelohde capillary method, the time it takes for the liquid to flow through the two graduations of a U-shaped capillary viscometer under gravity was measured, and the viscosity of the sample was calculated using a formula.

[0018] The number-average molecular weight of the polydimethylsiloxane was determined by gel permeation chromatography (GPC).

[0019] In Equations I and II, R 1 R 2 and R 3 They can be completely different, or two or three of them can be the same; X and Y can be the same or different; n and m can be the same or different.

[0020] For example, the C1 to C8 straight-chain alkyl group is at least one of C1, C2, C3, C4, C5, C6, C7 or C8 straight-chain alkyl groups.

[0021] For example, the C3-C8 branched alkyl group is at least one of C3, C4, C5, C6, C7, or C8 branched alkyl groups. In some embodiments, the C3-C8 branched alkyl group is at least one of (CH3)2CH-, (CH3)2CHCH2-, (CH3)3C-, (CH3)2CHCH2CH2-, CH3CH2CH(CH3)CH2-, (CH3)3CCH2-, (CH3)2CHCH2CH2CH2-, CH3CH(CH3)CH2CH2CH2-, (CH3)2CHCH2CH2CH2CH2-, CH3CH2CH2CH2CH(CH3)CH2-, (CH3CH2)2CHCH2CH2-, (CH3)2CHCH2C(CH3)2CH2-, CH3CH2CH(CH2CH3)CH2CH2CH2-, or CH3CH2CH2CH2CH2CH(CH3)CH2-.

[0022] For example, the C3 to C8 cycloalkyl group is at least one of C3, C4, C5, C6, C7 or C8 cycloalkyl groups.

[0023] For example, the C7-C8 aralkyl group is at least one of C7 and C8 aralkyl groups. In the C7-C8 aralkyl group, the alkyl portion can be straight-chain or branched; the aromatic portion can be phenyl.

[0024] For example, aromatic groups include, but are not limited to, phenyl groups.

[0025] For example, n is selected from 2, 3 or 4.

[0026] For example, m is selected from 2, 3 or 4.

[0027] Preferably, R 1 and R 2 Each group is independently selected from the following groups: C1~C8 straight-chain alkyl, C3~C8 branched alkyl or C7~C8 aralkyl, which not only have excellent stability but are also easy to synthesize.

[0028] Preferably, the dialkyl-substituted phosphinate includes aluminum diethylphosphinate, aluminum di-n-propylphosphinate, aluminum diisopropylphosphinate, aluminum di-n-butylphosphinate, aluminum diisobutylphosphinate, aluminum di-n-pentylphosphinate, aluminum diisopentylphosphinate, aluminum di-n-hexylphosphinate, aluminum di-n-heptylphosphinate, aluminum di-n-octylphosphinate, aluminum diphenylethylphosphinate, zinc diethylphosphinate, zinc di-n-propylphosphinate, zinc diisopropylphosphinate, zinc diisopropylphosphinate, zinc diisobutylphosphinate, and aluminum diisopropylphosphinate. Zinc butylphosphinate, zinc di-n-pentylphosphinate, zinc di-isopentylphosphinate, zinc di-n-hexylphosphinate, zinc di-n-heptylphosphinate, zinc di-n-octylphosphinate, zinc diphenylethylphosphinate, magnesium diethylphosphinate, magnesium di-n-propylphosphinate, magnesium di-isopropylphosphinate, magnesium di-n-butylphosphinate, magnesium di-isobutylphosphinate, magnesium di-n-pentylphosphinate, magnesium di-isopentylphosphinate, magnesium di-n-hexylphosphinate, magnesium di-n-heptylphosphinate, magnesium di-n-octylphosphinate, zinc diphenylethylphosphinate Magnesium diphosphinate, titanium diethylphosphinate, titanium di-n-propylphosphinate, titanium diisopropylphosphinate, titanium di-n-butylphosphinate, titanium diisobutylphosphinate, titanium di-n-pentylphosphinate, titanium diisopentylphosphinate, titanium di-n-hexylphosphinate, titanium di-n-heptylphosphinate, titanium di-n-octylphosphinate, titanium diphenylethylphosphinate, calcium diethylphosphinate, calcium di-n-propylphosphinate, calcium diisopropylphosphinate, calcium di-n-butylphosphinate, calcium diisobutylphosphinate, calcium di-n-pentylphosphinate At least one of the following: calcium phosphonate, diisopentyl calcium phosphonate, di-n-hexyl calcium phosphonate, di-n-heptyl calcium phosphonate, di-n-octyl calcium phosphonate, diphenylethyl calcium phosphonate, diethylferric phosphonate, di-n-propylferric phosphonate, diisopropylferric phosphonate, di-n-butylferric phosphonate, diisobutylferric phosphonate, di-n-pentylferric phosphonate, diisopentylferric phosphonate, di-n-heptylferric phosphonate, di-n-octylferric phosphonate, and diphenylethylferric phosphonate.

[0029] Preferably, the monoalkyl-substituted phosphinate includes aluminum ethylphosphinate, aluminum n-propylphosphinate, aluminum isopropylphosphinate, aluminum n-butylphosphinate, aluminum isobutylphosphinate, aluminum n-pentylphosphinate, aluminum isopentylphosphinate, aluminum n-hexylphosphinate, aluminum n-heptylphosphinate, aluminum n-octylphosphinate, aluminum cyclohexylphosphinate, aluminum phenylphosphinate, aluminum benzylphosphinate, aluminum phenylethylphosphinate, zinc ethylphosphinate, zinc n-propylphosphinate, zinc isopropylphosphinate, zinc n-butylphosphinate, zinc isobutylphosphinate, and zinc n-pentylphosphinate. Zinc phosphonate, zinc isopentyl phosphonate, zinc n-hexyl phosphonate, zinc n-heptyl phosphonate, zinc n-octyl phosphonate, zinc cyclohexyl phosphonate, zinc phenyl phosphonate, zinc benzyl phosphonate, zinc phenethyl phosphonate, magnesium ethyl phosphonate, magnesium n-propyl phosphonate, magnesium isopropyl phosphonate, magnesium n-butyl phosphonate, magnesium isobutyl phosphonate, magnesium n-pentyl phosphonate, magnesium isopentyl phosphonate, magnesium n-hexyl phosphonate, magnesium n-heptyl phosphonate, magnesium n-octyl phosphonate, magnesium cyclohexyl phosphonate, magnesium phenyl phosphonate, magnesium benzyl phosphonate, magnesium phenyl phosphonate, magnesium phenethyl phosphonate, magnesium phenyl ... Magnesium phosphinate, Titanium ethyl phosphinate, Titanium n-propyl phosphinate, Titanium isopropyl phosphinate, Titanium n-butyl phosphinate, Titanium isobutyl phosphinate, Titanium n-pentyl phosphinate, Titanium isopentyl phosphinate, Titanium n-hexyl phosphinate, Titanium n-heptyl phosphinate, Titanium n-octyl phosphinate, Titanium cyclohexyl phosphinate, Titanium phenyl phosphinate, Titanium benzyl phosphinate, Titanium phenylethyl phosphinate, Calcium ethyl phosphinate, Calcium n-propyl phosphinate, Calcium isopropyl phosphinate, Calcium n-butyl phosphinate, Calcium isobutyl phosphinate, Calcium n-pentyl phosphinate, Calcium isopentyl phosphinate At least one of the following: calcium hexylphosphonate, calcium heptylphosphonate, calcium octylphosphonate, calcium cyclohexylphosphonate, calcium phenylphosphonate, calcium benzylphosphonate, calcium phenylethylphosphonate, iron ethylphosphonate, iron propylphosphonate, iron isopropylphosphonate, iron butylphosphonate, iron isobutylphosphonate, iron pentylphosphonate, iron isopentylphosphonate, iron hexylphosphonate, iron heptylphosphonate, iron octylphosphonate, iron cyclohexylphosphonate, iron phenylphosphonate, iron benzylphosphonate, and iron phenylethylphosphonate.

[0030] In some embodiments, the di(or mono)alkyl-substituted phosphonates can be commercially available or prepared using conventional methods in the art, including but not limited to the following methods. For example, a method for preparing di(or mono)alkyl-substituted phosphonates includes the following steps: Sodium di(or mono)alkyl-substituted hypophosphonates are mixed with water-soluble salts to undergo a metathesis reaction to obtain di(or mono)alkyl-substituted hypophosphonate products.

[0031] Among them, dialkyl-substituted sodium hypophosphite is at least one of the compounds of formula III. ； Among them, R 1 and R 2Each group is independently selected from the following groups: C1~C8 straight-chain alkyl, C3~C8 branched alkyl, C3~C8 cycloalkyl, C7~C8 aralkyl, and aromatic group.

[0032] In Formula III, R 1 and R 2 They can be the same, yet they can also be different.

[0033] In Equation III, when R 1 and / or R 2 When selected from C1-C8 straight-chain alkyl groups, the C1-C8 straight-chain alkyl groups can be at least one of C1, C2, C3, C4, C5, C6, C7 or C8 straight-chain alkyl groups.

[0034] In Equation III, when R 1 and / or R 2 When selected from C3-C8 branched alkyl groups, the C3-C8 branched alkyl groups can be at least one of C3, C4, C5, C6, C7 or C8 branched alkyl groups. In one embodiment, the C3-C8 branched alkyl group is at least one of (CH3)2CH-, (CH3)2CHCH2-, (CH3)3C-, (CH3)2CHCH2CH2-, CH3CH2CH(CH3)CH2-, (CH3)3CCH2-, (CH3)2CHCH2CH2CH2-, CH3CH(CH3)CH2CH2CH2-, (CH3)2CHCH2CH2CH2CH2-, CH3CH2CH2CH2CH(CH3)CH2-, (CH3CH2)2CHCH2CH2-, (CH3)2CHCH2C(CH3)2CH2-, CH3CH2CH(CH2CH3)CH2CH2CH2-, or CH3CH2CH2CH2CH2CH(CH3)CH2-.

[0035] In Equation III, when R 1 and / or R 2 When selected from C3-C8 cycloalkyl groups, the C3-C8 cycloalkyl group can be at least one of C3, C4, C5, C6, C7, or C8 cycloalkyl groups.

[0036] In Equation III, when R 1 and / or R 2 When selected from C7-C8 aralkyl groups, the C7-C8 aralkyl group can be at least one of C7 and C8 aralkyl groups. In a C7-C8 aralkyl group, the alkyl moiety can be straight-chain or branched; the aromatic moiety can be phenyl.

[0037] In Equation III, when R 1 and / or R 2 When selected from aromatic groups, the aromatic group can be phenyl.

[0038] In some embodiments, the dialkyl-substituted sodium hypophosphite used includes at least one of sodium diethylphosphite, sodium di-n-propylphosphite, sodium diisopropylphosphite, sodium di-n-butylphosphite, sodium diisobutylphosphite, sodium di-n-pentylphosphite, sodium di-n-hexylphosphite, sodium di-n-heptylphosphite, and sodium di-n-octylphosphite.

[0039] Sodium hypophosphite with a monoalkyl substituted group is at least one of the compounds of formula IV. ; R 3 Selected from the following groups: C1~C8 straight-chain alkyl, C3~C8 branched alkyl, C3~C8 cycloalkyl, C7~C8 aralkyl, aromatic group.

[0040] In Equation IV, when R 3 When selected from C1 to C8 straight-chain alkyl groups, the C1 to C8 straight-chain alkyl groups can be C1, C2, C3, C4, C5, C6, C7, or C8 straight-chain alkyl groups.

[0041] In Equation IV, when R 3 When selected from C3-C8 branched alkyl groups, the C3-C8 branched alkyl groups can be C3, C4, C5, C6, C7 or C8 branched alkyl groups. In one embodiment, the C3-C8 branched alkyl group is (CH3)2CH-, (CH3)2CHCH2-, (CH3)3C-, (CH3)2CHCH2CH2-, CH3CH2CH(CH3)CH2-, (CH3)3CCH2-, (CH3)2CHCH2CH2CH2-, CH3CH(CH3)CH2CH2CH2-, (CH3)2CHCH2CH2CH2CH2-, CH3CH2CH2CH2CH(CH3)CH2-, (CH3CH2)2CHCH2CH2-, (CH3)2CHCH2C(CH3)2CH2-, CH3CH2CH(CH2CH3)CH2CH2CH2-, or CH3CH2CH2CH2CH2CH(CH3)CH2-.

[0042] In Equation IV, when R 3 When selected from C3 to C8 cycloalkyl groups, the C3 to C8 cycloalkyl groups can be C3, C4, C5, C6, C7, or C8 cycloalkyl groups.

[0043] In Equation IV, when R 3 When selected from C7-C8 aralkyl groups, the C7-C8 aralkyl group can be at least one of C7 and C8 aralkyl groups. In a C7-C8 aralkyl group, the alkyl moiety can be straight-chain or branched; the aromatic moiety can be phenyl.

[0044] In Equation IV, when R 3 When selected from aromatic groups, the aromatic group can be phenyl.

[0045] In some embodiments, the monoalkyl-substituted sodium hypophosphite used includes at least one of sodium ethyl phosphite, sodium n-propyl phosphite, sodium isopropyl phosphite, sodium n-butyl phosphite, sodium isobutyl phosphite, and sodium phenyl phosphite.

[0046] The water-soluble salt is a water-soluble salt of at least one metal selected from Al, Mg, Ca, Zn, Ti, and Fe. In some embodiments, the water-soluble salt is at least one selected from water-soluble chloride, water-soluble nitrate, and water-soluble sulfate. For example, the water-soluble salt includes at least one selected from aluminum nitrate, aluminum sulfate, magnesium chloride, magnesium nitrate, magnesium sulfate, calcium chloride, calcium nitrate, zinc chloride, zinc nitrate, zinc sulfate, ferric chloride, ferric nitrate, and ferric sulfate.

[0047] In one embodiment, when sodium di(or mono)alkyl-substituted phosphonate undergoes a metathesis reaction with a water-soluble salt, the reaction temperature is controlled at 80-90°C.

[0048] In one embodiment, the molar ratio of di(or mono)alkyl-substituted sodium hypophosphite to the water-soluble salt is (0.5~8):1.

[0049] In one embodiment, before mixing the di(or mono)alkyl-substituted sodium hypophosphite with the water-soluble salt, the di(or mono)alkyl-substituted sodium hypophosphite is diluted with a solvent to a content of 20wt% to 40wt%, and the pH value is adjusted to between 2 and 3 with an acid. The solvent can be water, etc.; the acid used to adjust the pH value can be sulfuric acid, etc.

[0050] In one embodiment, when di(or mono)alkyl-substituted sodium hypophosphite is mixed with a water-soluble salt, the water-soluble salt is introduced in the form of a solution, wherein the content of the water-soluble salt in the solution is 20wt% to 25wt%.

[0051] In one embodiment, the metathesis reaction is carried out under an inert atmosphere. The inert atmosphere may be nitrogen or / or argon.

[0052] In one embodiment, the preparation method of the di(or mono)hydrocarbon substituted phosphonate further includes the following steps: after metathesis reaction, crystallization, solid-liquid separation, washing, and drying.

[0053] Di(or mono) alkyl-substituted phosphonates can also be prepared by other methods, such as the free radical addition method described in the literature (Zhang Mengting. Synthesis Research of Novel Phosphorus Flame Retardants [D]. Southeast University, 2022).

[0054] In some embodiments, the mass percentage of bromine in the PA composition is 7% to 14%, such as the range formed by any two of 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, or more.

[0055] In some embodiments, the bromine-based flame retardant contains 50% to 85% bromine by mass, such as 50%, 55%, 60%, 65%, 70%, 75%, 80%, or 85%.

[0056] The mass percentage of bromine in the brominated flame retardant was determined by high-temperature alkali fusion-potential titration, as follows: Accurately weigh 0.30 g of the brominated flame retardant sample powder, add 1.0 g of solid Na₂CO₃ and 3.5 g of solid NaOH, heat until the alkali becomes molten, and continue heating until the brominated flame retardant sample powder is fully absorbed by the alkali (i.e., the brominated flame retardant sample powder completely disappears). Cool, add water to dissolve the sample, pour into a 250 mL volumetric flask, dilute to volume, shake well, accurately pipette 5 mL of the sample solution into a titration cup, add 50 mL of water and 10 mL of nitric acid solution (68 wt%), stir to disperse, and titrate to the endpoint with silver nitrate standard titration solution. Calculate the mass percentage of bromine content based on the titration results.

[0057] In some embodiments, the brominated flame retardant includes at least one of brominated triazine, brominated epoxy resin, decabromodiphenyl ethane, ethylene bis(tetrabromophthalimide), brominated polystyrene, polybrominated styrene, brominated polycarbonate, and brominated polyacrylate.

[0058] The brominated epoxy resin can be end-capped or unend-capped. In some embodiments, the end-capping groups are derived from phenolic compounds, such as tribromophenol.

[0059] In some embodiments, the weight-average molecular weight of the brominated epoxy resin is 700-3000, such as the range formed by any two of 700, 1000, 1200, 1500, 1800, 2000, 2200, 2500, 3000 or above.

[0060] In some embodiments, the weight-average molecular weight of the brominated polystyrene is 3000-8000, such as the range formed by any two of the following: 3000, 3500, 4000, 4500, 5000, 5500, 6000, 6500, 7000, 7500, 8000 or above.

[0061] In some embodiments, the weight-average molecular weight of the polybrominated styrene is 3000-8000, such as the range formed by any two of the following: 3000, 3500, 4000, 4500, 5000, 5500, 6000, 6500, 7000, 7500, 8000 or more.

[0062] In some embodiments, the weight-average molecular weight of the brominated polycarbonate is 3500-8500, such as the range formed by any two of the following: 3500, 4000, 4500, 5000, 5500, 6000, 6500, 7000, 7500, 8000, 8500.

[0063] In some embodiments, the brominated polyacrylate has a weight-average molecular weight of 500,000-700,000, such as the range formed by any two of the following: 500,000, 520,000, 540,000, 560,000, 580,000, 600,000, 620,000, 640,000, 660,000, 680,000, 700,000. The brominated polyacrylate includes, but is not limited to, pentabromobenzyl polyacrylate.

[0064] The weight-average molecular weights of brominated epoxy resins, brominated polystyrene, polybrominated styrene, brominated polycarbonate, and brominated polyacrylate were determined by gel permeation chromatography. In some embodiments, the melting point of the PA resin is in the range of 210°C to 280°C, such as 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C or 280°C.

[0065] The melting point of the PA resin was determined by DSC (differential scanning calorimetry).

[0066] In some embodiments, the PA resin includes at least one of PA6, PA66, and PA56.

[0067] Preferably, the PA composition further comprises the following components in parts by weight: 0.1 to 0.4 parts of an anti-drip agent to improve anti-drip performance, which is beneficial for achieving thin-walled UL-94 V-0. For example, the anti-drip agent is 0.1, 0.2, 0.3, or 0.4 parts by weight.

[0068] In some embodiments, the anti-dripping agent includes at least one of polytetrafluoroethylene (PTFE), styrene-acrylonitrile random copolymer coated PTFE, styrene-methyl methacrylate copolymer coated PTFE, and silicone resin coated PTFE.

[0069] Other additives may be added to the PA composition as needed to improve properties such as thermal stability, processability, weather resistance, and / or color. In some embodiments, the other additives include at least one of antioxidants, weather-resistant agents, colorants, and antistatic agents.

[0070] The antioxidant can be selected with reference to existing technologies, such as at least one of hindered phenolic antioxidants, phosphite antioxidants, divalent sulfur antioxidants, hindered amine antioxidants, benzofuranone antioxidants, etc.

[0071] Specifically, the hindered phenolic antioxidants include, but are not limited to, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010), octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (antioxidant 1076), N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine (antioxidant 1098), 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene (antioxidant 1330), 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid (antioxidant 3114), 1,2-bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine (antioxidant 1024), and triethylene glycol. Ether-di(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate (antioxidant 245), 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), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane (antioxidant CA), 2-tert-butyl-6-(3-tert-butyl-5-methyl-2-hydroxyphenyl)-4-methylphenyl acrylate, 2-(2-hydroxy-3-tert-butyl-5-methylbenzyl)-4-methyl-6-tert-butylphenyl acrylate (antioxidant GM), 2,6-di-tert-butyl-4-methylphenol (antioxidant 264), styrene-modified phenol (anti-aging agent SP), 2, At least one of 2'-methylenebis(4-methyl-6-tert-butylphenol) (antioxidant 2246); The phosphite antioxidants include, but are not limited to, at least one of the following: tris[2,4-di-tert-butylphenyl]phosphite (antioxidant 168), 3,9-bis(2,4-dicumylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane (antioxidant 9228), tris(nonylphenyl)phosphite (antioxidant TNP), bis(4-octylphenol) diphosphate (antioxidant 1093); The divalent sulfur antioxidants include, but are not limited to, at least one of dilaurate thiodipropionate (DLTP), distearate thiodipropionate (DSTP), and pentaerythritol tetra(3-lauryl thiopropionate) (antioxidant 412S); The hindered amine antioxidants include, but are not limited to, at least one of the following: bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate (LS-744), sebacate bis-2,2,6,6-tetramethylpiperidinol ester (LS-770), tris(1,2,2,6,6-pentamethylpiperidinol) phosphite (GW-540), and 4,4'-adipamide diaminobis(2,2,6,6-tetramethylpiperidin-1-oxy) (FlamstabNOR116); The benzofuranone antioxidants include, but are not limited to, at least one of 5,7-bis(1,1-dimethylethyl)-3-[2,3-dimethylphenyl]-2(3H)-benzofuranone (antioxidant 136) and 4-tert-butyl-2-(5-tert-butyl-2-oxo-3H-1-benzofuran-3-yl)phenyl 3,5-di-tert-butyl-4-hydroxybenzoate (antioxidant 501).

[0072] In some embodiments, the antioxidant includes hindered phenolic antioxidants and phosphite antioxidants, wherein the weight ratio of the hindered phenolic antioxidants to the phosphite antioxidants is (1~3):1.

[0073] The weathering agent can be selected with reference to existing technologies, such as at least one of benzophenone-based ultraviolet absorbers and benzotriazole-based ultraviolet absorbers.

[0074] The colorant can be selected with reference to existing technologies, and includes, but is not limited to, at least one of pigments and dyes. Examples of pigments include titanium dioxide, phthalocyanine, ultramarine, iron oxide, or carbon black, and one or more of all organic pigments. Examples of dyes include one or more of azo yellow, quinacridone, perylene red, dioxazine, indolinone, isoindolin, anthraquinone blue, and anthraquinone violet.

[0075] The antistatic agent can be selected with reference to existing technologies, such as at least one of alkyl sulfonates, quaternary ammonium salts, glyceryl monostearate (GMS), ethoxylated alkylamines, polyether block amides (PEBA), carbon nanotubes, graphene, etc.

[0076] In some embodiments, the other adjuvants are 0 to 5 parts by weight, such as 0.1 parts by weight, 0.3 parts by weight, 0.5 parts by weight, 0.7 parts by weight, 1 part by weight, 1.2 parts by weight, 1.4 parts by weight, 1.6 parts by weight, 1.8 parts by weight, 2 parts by weight, 2.2 parts by weight, 2.4 parts by weight, 2.6 parts by weight, 2.8 parts by weight, 3 parts by weight, 3.2 parts by weight, 3.5 parts by weight, 3.8 parts by weight, 4 parts by weight, 4.2 parts by weight, 4.5 parts by weight, 4.8 parts by weight, 5 parts by weight, or any range formed by two or more of these.

[0077] Secondly, this application provides a method for preparing a PA composition, comprising the following steps: mixing and dispersing the component raw materials, melt extruding, granulating, and obtaining the PA composition.

[0078] In one embodiment, melt extrusion is performed in a co-rotating twin-screw extruder when preparing the PA composition.

[0079] In one embodiment, the melt extrusion temperature is 230~280℃; the screw speed is 300-600 rpm; the screw length-to-diameter ratio is 36:1~48:1; and the feeding speed is 450~800 kg / h.

[0080] Thirdly, this application provides a molded part formed from the PA composition.

[0081] The molding method can be selected with reference to existing technologies, such as including but not limited to injection molding, extrusion molding, blow molding, rotational molding and / or compression molding.

[0082] The PA composition can be applied in fields such as automotive, electronics and electrical and mechanical industries, such as the manufacture of automotive engine covers, high-voltage switch housings and gears or bearings for transmission equipment.

[0083] Compared with the prior art, the beneficial effects of this application are as follows: by simultaneously adding specific amounts of dialkyl-substituted phosphinates, monoalkyl-substituted phosphinates, brominated flame retardants and specific lubricants to PA resin, this application can make the material have both good flame retardancy and low surface friction coefficient, making it suitable for application in the automotive, electronics and electrical and mechanical industries. Detailed Implementation

[0084] To better illustrate the purpose, technical solutions, and advantages of this application, the following description, in conjunction with specific embodiments and comparative examples, aims to provide a detailed understanding of the content of this application, rather than limiting it. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this application. Unless otherwise specified, the experimental reagents and instruments involved in the implementation of this application are commonly used reagents and instruments. In this application, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0085] The raw materials used in the following embodiments and comparative examples are shown below. Unless otherwise specified, all raw materials are commercially available. In addition, the same raw materials were used in each parallel experiment: PA Resin 1: Melting point 220-225℃, Ultramid® B3 (BASF), BASF; PA Resin 2: Melting point 260-265℃, Zytel® 101 (DuPont); Dialkyl-substituted phosphonates 1: Aluminum diethylphosphonate, prepared as follows: Sodium diethylphosphonate is diluted with water to a concentration of 35 wt%, the pH is adjusted to 2.5 with sulfuric acid, and aluminum sulfate solution (aluminum sulfate content is 25 wt%) is added to carry out the reaction. The reaction is carried out under a nitrogen atmosphere and the reaction temperature is controlled at 85℃. After the reaction is completed, crystallize, filter, wash, and dry to obtain aluminum diethylphosphonate.

[0086] Dialkyl-substituted phosphinate 2: di-n-octylphosphinate aluminum, was prepared according to the process described in Sections 3.2.2 to 3.2.3 of the literature (Zhang Mengting. Synthesis Study of Novel Phosphorus Flame Retardants [D]. Southeast University, 2022).

[0087] Dialkyl-substituted phosphonate 3: aluminum diisopropylphosphonate, whose preparation method differs from that of dialkyl-substituted phosphonate 1 in that sodium diisopropylphosphonate is used instead of sodium diethylphosphonate.

[0088] Dihydro-substituted phosphonate 4: Zinc diethylphosphonate, the preparation method of which differs from that of dihydro-substituted phosphonate 1, is that zinc chloride solution (zinc chloride content of 22wt%) is used to completely replace aluminum sulfate solution.

[0089] Monoalkyl-substituted phosphonate 1: Aluminum ethylphosphonate, whose preparation method differs from that of dialkyl-substituted phosphonate 1 in that sodium ethylphosphonate is used instead of sodium diethylphosphonate.

[0090] Monoalkyl-substituted phosphonate 2: aluminum n-butylphosphonate, whose preparation method differs from that of monoalkyl-substituted phosphonate 1 in that sodium n-butylphosphonate is used instead of sodium ethylphosphonate.

[0091] Monoalkyl-substituted phosphinate 3: Aluminum phenylphosphinate, Hubei Chuyuebang New Material Technology Co., Ltd.

[0092] Monoalkyl-substituted phosphonate 4: Zinc ethylphosphonate, the preparation method of which differs from that of monoalkyl-substituted phosphonate 1, is that zinc chloride solution (zinc chloride content of 22wt%) is used to completely replace aluminum sulfate solution.

[0093] Brominated flame retardant 1: Bromotriazine, FR-245, ICL-IP.

[0094] Brominated flame retardant 2: Brominated epoxy resin, F-3014, ICL-IP.

[0095] Bromine-based flame retardant 3: Brominated polystyrene, SR-3010, Shandong Xurui New Material Co., Ltd.

[0096] Brominated flame retardant 4: Poly(pentabromobenzyl) acrylate, FR-1025, ICL-IP.

[0097] Lubricant 1: Oxidized polyethylene wax, 629A, Honeywell.

[0098] Lubricant 2: Pentaerythritol stearate, PETS-AP, Guangdong Dingxin Polymer Technology Co., Ltd.

[0099] Lubricant 3: Polydimethylsiloxane, PSF-100 cSt, Dow Corning.

[0100] Lubricant 4: Calcium stearate, Jiangxi Hongyuan Chemical Co., Ltd.

[0101] Lubricant 5: Ethylene bis-stearamide, EBS B50, Shenzhen Yoshida Chemical Co., Ltd.

[0102] Anti-dripping agent: styrene-methyl methacrylate copolymer coated polytetrafluoroethylene, Shanghai Puxin Polymer Materials Co., Ltd., DB109.

[0103] Additive: A mixture of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris[2,4-di-tert-butylphenyl]phosphite in a weight ratio of 2:1, commercially available.

[0104] The following examples and comparative examples all provide a PA composition, and their preparation methods include the following steps: According to the PA composition formulations in Tables 1 and 2, all materials were added to a mixer according to the specified ratio and mixed at 1200 rpm for 8 minutes. The mixture was then removed and fed into the feed hopper of a co-rotating twin-screw extruder for melting. After water cooling, the mixture was stretched and pelletized to obtain the PA composition. The process parameters of the twin-screw extruder were as follows: Zone 1 temperature 220℃, Zone 2 temperature 230℃, Zone 3 temperature 230℃, Zone 4 temperature 240℃, Zone 5 temperature 240℃, Zone 6 temperature 250℃, Zone 7 temperature 260℃, Zone 8 temperature 260℃, Zone 9 temperature 270℃, die head temperature 275℃, screw speed setting range 500 rpm, screw length-to-diameter ratio 36:1, and feeding speed 600 kg / h.

[0105] Table 1 Table 2 The PA compositions of the above embodiments and comparative examples were subjected to the following performance tests: (1) Flame retardant performance: The PA composition was injection molded into standard strips with a thickness of 2.0 mm, and the vertical burning flame retardant performance of the strips was tested according to UL94-2023 standard; (2) Surface friction coefficient: The surface dynamic friction coefficient is tested according to GB / T 10006-2021 standard.

[0106] The test results are shown in Table 3.

[0107] Table 3 As can be seen from the above data, the PA compositions in the above embodiments have both good flame retardancy and low surface friction coefficient. For example, the flame retardancy (thickness 2.0mm) reaches V-0 level, and the surface dynamic friction coefficient is below 0.120.

[0108] Comparative Examples 1 and 2, lacking either hydrocarbon-substituted phosphines or brominated flame retardants, exhibited significantly deteriorated flame retardancy, indicating that hydrocarbon-substituted phosphines and brominated flame retardants synergistically improve the flame retardancy of the compositions.

[0109] Comparative Examples 3 and 4, lacking either dialkyl-substituted or monoalkyl-substituted phosphonates, exhibited significantly deteriorated flame retardancy, indicating that dialkyl-substituted and monoalkyl-substituted phosphonates synergistically improve flame retardancy.

[0110] Comparative Example 5 contained no lubricant, while Comparative Examples 6 and 7 used other lubricants, both of which resulted in a higher coefficient of dynamic friction on the surface.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit the scope of protection of this application. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the substance and scope of the technical solutions of this application.

Claims

1. A PA composition, characterized in that, It includes the following components in parts by weight: 50-78.5 parts PA resin, 3-12 parts dialkyl-substituted phosphinate, 0.3-3 parts monoalkyl-substituted phosphinate, 10-25 parts brominated flame retardant, and 3-15 parts lubricant; The dialkyl-substituted phosphonate is at least one of the compounds of formula I, and the monoalkyl-substituted phosphonate is at least one of the compounds of formula II. ， Among them, R 1 R 2 and R 3 Each group is independently selected from the following groups: C1-C8 straight-chain alkyl, C3-C8 branched alkyl, C3-C8 cycloalkyl, C7-C8 aralkyl, and aryl. X and Y are each independently selected from Al, Mg, Ca, Zn, Ti, or Fe. n and m are each independently selected from integers between 2 and 4; The lubricant is selected from at least one of polyethylene wax, stearate, and polydimethylsiloxane.

2. The PA composition according to claim 1, characterized in that, At least one of the following conditions must be met: (1) The polyethylene wax is oxidized polyethylene wax with an acid value range of 0-80 mg KOH / g and a number-average molecular weight range of 1500~5000 g / mol; (2) The stearate is pentaerythritol stearate, with a saponification value range of 120-160 mg KOH / g; (3) The viscosity of the polydimethylsiloxane at 25°C is 10 to 2,000,000 cSt and the number average molecular weight is 1,000 to 500,000 g / mol.

3. The PA composition according to claim 1, characterized in that, The dialkyl-substituted phosphines include aluminum diethylphosphines, aluminum di-n-propylphosphines, aluminum diisopropylphosphines, aluminum di-n-butylphosphines, aluminum diisobutylphosphines, aluminum di-n-pentylphosphines, aluminum diisopentylphosphines, aluminum di-n-hexylphosphines, aluminum di-n-heptylphosphines, aluminum di-n-octylphosphines, aluminum diphenylethylphosphines, zinc diethylphosphines, zinc di-n-propylphosphines, zinc diisopropylphosphines, zinc di-n-butylphosphines, and zinc diisobutylphosphines. Zinc phosphonate, di-n-pentyl zinc phosphonate, di-isopentyl zinc phosphonate, di-n-hexyl zinc phosphonate, di-n-heptyl zinc phosphonate, di-n-octyl zinc phosphonate, diphenylethyl zinc phosphonate, diethyl magnesium phosphonate, di-n-propyl magnesium phosphonate, di-isopropyl magnesium phosphonate, di-n-butyl magnesium phosphonate, di-isobutyl magnesium phosphonate, di-n-pentyl magnesium phosphonate, di-isopentyl magnesium phosphonate, di-n-hexyl magnesium phosphonate, di-n-heptyl magnesium phosphonate, di-n-octyl magnesium phosphonate, diphenylethyl zinc phosphonate Magnesium phosphonate, diethylphosphonate titanium, di-n-propylphosphonate titanium, diisopropylphosphonate titanium, di-n-butylphosphonate titanium, diisobutylphosphonate titanium, di-n-pentylphosphonate titanium, diisopentylphosphonate titanium, di-n-hexylphosphonate titanium, di-n-heptylphosphonate titanium, di-n-octylphosphonate titanium, diphenylethylphosphonate titanium, calcium diethylphosphonate, calcium di-n-propylphosphonate, calcium diisopropylphosphonate, calcium di-n-butylphosphonate, calcium diisobutylphosphonate, di-n-pentylphosphonate The first of the following: calcium phosphite, diisopentyl calcium phosphite, di-n-hexyl calcium phosphite, di-n-heptyl calcium phosphite, di-n-octyl calcium phosphite, diphenylethyl calcium phosphite, diethylferric phosphite, di-n-propylferric phosphite, diisopropylferric phosphite, di-n-butylferric phosphite, diisobutylferric phosphite, di-n-pentylferric phosphite, diisopentylferric phosphite, di-n-hexylferric phosphite, di-n-heptylferric phosphite, and diphenylethylferric phosphite.

4. The PA composition according to claim 1, characterized in that, The monoalkyl-substituted phosphinates include aluminum ethylphosphinate, aluminum n-propylphosphinate, aluminum isopropylphosphinate, aluminum n-butylphosphinate, aluminum isobutylphosphinate, aluminum n-pentylphosphinate, aluminum isopentylphosphinate, aluminum n-hexylphosphinate, aluminum n-heptylphosphinate, aluminum n-octylphosphinate, aluminum cyclohexylphosphinate, aluminum phenylphosphinate, aluminum benzylphosphinate, aluminum phenethylphosphinate, zinc ethylphosphinate, zinc n-propylphosphinate, zinc isopropylphosphinate, zinc n-butylphosphinate, zinc isobutylphosphinate, and zinc n-pentylphosphinate. Zinc isopentyl phosphinate, zinc n-hexyl phosphinate, zinc n-heptyl phosphinate, zinc n-octyl phosphinate, zinc cyclohexyl phosphinate, zinc phenyl phosphinate, zinc benzyl phosphinate, zinc phenethyl phosphinate, magnesium ethyl phosphinate, magnesium n-propyl phosphinate, magnesium isopropyl phosphinate, magnesium n-butyl phosphinate, magnesium isobutyl phosphinate, magnesium n-pentyl phosphinate, magnesium isopentyl phosphinate, magnesium n-hexyl phosphinate, magnesium n-heptyl phosphinate, magnesium n-octyl phosphinate, magnesium cyclohexyl phosphinate, magnesium phenyl phosphinate, magnesium benzyl phosphinate, magnesium phenethyl phosphinate Magnesium phosphonate, ethyl phosphonate titanium, n-propyl phosphonate titanium, isopropyl phosphonate titanium, n-butyl phosphonate titanium, isobutyl phosphonate titanium, n-pentyl phosphonate titanium, isopentyl phosphonate titanium, n-hexyl phosphonate titanium, n-heptyl phosphonate titanium, n-octyl phosphonate titanium, cyclohexyl phosphonate titanium, phenyl phosphonate titanium, benzyl phosphonate titanium, phenylethyl phosphonate titanium, ethyl phosphonate calcium, n-propyl phosphonate calcium, isopropyl phosphonate calcium, n-butyl phosphonate calcium, isobutyl phosphonate calcium, n-pentyl phosphonate calcium, isopentyl phosphonate calcium At least one of the following: calcium hexylphosphonate, calcium heptylphosphonate, calcium octylphosphonate, calcium cyclohexylphosphonate, calcium phenylphosphonate, calcium benzylphosphonate, calcium phenylethylphosphonate, iron ethylphosphonate, iron propylphosphonate, iron isopropylphosphonate, iron butylphosphonate, iron isobutylphosphonate, iron pentylphosphonate, iron isopentylphosphonate, iron hexylphosphonate, iron heptylphosphonate, iron octylphosphonate, iron cyclohexylphosphonate, iron phenylphosphonate, iron benzylphosphonate, and iron phenylethylphosphonate.

5. The PA composition according to claim 1, characterized in that, The PA composition contains 7% to 14% bromine by mass.

6. The PA composition according to claim 1, characterized in that, The brominated flame retardant includes at least one of the following: brominated triazine, brominated epoxy resin, decabromodiphenyl ethane, ethylene bis(tetrabromophthalimide), brominated polystyrene, polybrominated styrene, brominated polycarbonate, and brominated polyacrylate.

7. The PA composition according to claim 1, characterized in that, The melting point of the PA resin is in the range of 210℃ to 280℃.

8. The PA composition according to claim 1, characterized in that, The PA composition further includes the following components in parts by weight: 0.1 to 0.4 parts of anti-dripping agent; the anti-dripping agent preferably includes at least one of polytetrafluoroethylene, polytetrafluoroethylene coated with styrene-acrylonitrile random copolymer, polytetrafluoroethylene coated with styrene-methyl methacrylate copolymer, and polytetrafluoroethylene coated with silicone resin.

9. The method for preparing the PA composition according to any one of claims 1 to 8, characterized in that, Includes the following steps: The raw materials are mixed and dispersed, melt-extruded, and granulated to obtain the PA composition.

10. A molded part, characterized in that, It is formed from the PA composition as described in any one of claims 1 to 8.

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