PBT Compositions, Preparation Methods, and Molded Parts

Abstract

This application discloses a PBT composition, its preparation method, and molded parts, belonging to the field of polymer materials technology. By selecting PBT with a specific intrinsic viscosity as the matrix resin and adding specific amounts of dialkyl-substituted phosphinates, monoalkyl-substituted phosphinates, and brominated flame retardants, the resulting composition exhibits both good flame retardancy and low fouling during processing, making it suitable for applications in electronics, home appliances, automobiles, and other fields.

Description

Technical Field

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

[0002] Polybutylene terephthalate (PBT), as a type of crystalline thermoplastic polyester, possesses a comprehensive set of advantages, including rapid crystallization rate, excellent mechanical properties, superior thermal stability and chemical corrosion resistance, outstanding electrical insulation properties, and good processing fluidity, leading to its widespread application in industrial production. However, pure PBT itself has poor flame retardant properties, making it difficult to meet the requirements of applications with high flame retardant requirements. Flame retardant modification of PBT suffers from problems such as low flame retardant efficiency and high proportions of flame retardants, and is prone to significant mold fouling during high-temperature processing, severely affecting processing stability and product quality. Therefore, there is an urgent need to develop a PBT material that can significantly reduce mold fouling while maintaining flame retardant properties. Summary of the Invention

[0003] Based on the deficiencies of the existing technology, the purpose of this application is to provide a PBT composition, its preparation method and molded parts, wherein the PBT composition has good flame retardancy and produces less mold fouling during processing.

[0004] To achieve the above objectives, in a first aspect, this application provides a PBT composition comprising the following components in parts by weight: 35-86 parts of PBT resin, 2.4-14 parts of dialkyl-substituted phosphinate, 0.15-3 parts of monoalkyl-substituted phosphinate, and 10-21 parts of brominated flame retardant. 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 intrinsic viscosity of the PBT resin at 25°C is ≤0.9 dL / g. Due to the combined effect of the above components, the PBT composition not only exhibits good flame retardancy but also produces minimal mold residue during processing.

[0005] The PBT resin is in the range of 35 to 86 parts by weight, such as 35 parts by weight, 40 parts by weight, 45 parts by weight, 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight, 80 parts by weight, 86 parts by weight, or any two of these ranges. Preferably, the PBT in the PBT composition accounts for more than 30% by weight, such as 30%, 40%, 50%, 60%, 70%, 80%, 82%, 84%, 86%, or any two of these ranges.

[0006] The dialkyl-substituted phosphonate is 2.4 to 14 parts by weight, such as 2.4 parts by weight, 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, or any two of the above ranges.

[0007] The monoalkyl-substituted phosphonate is 0.15 to 3 parts by weight, such as 0.15 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.

[0008] The brominated flame retardant is 10 to 21 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, or any two of the above ranges.

[0009] The intrinsic viscosity of the PBT resin at 25°C is ≤0.9 dL / g, such as 0.9 dL / g, 0.8 dL / g, 0.7 dL / g, 0.6 dL / g, 0.5 dL / g, 0.4 dL / g, 0.3 dL / g, or any two of the above ranges. Preferably, the intrinsic viscosity of the PBT resin at 25°C is 0.6~0.75 dL / g, to better reduce the amount of mold fouling during processing.

[0010] The intrinsic viscosity of the PBT resin at 25°C was measured according to ISO 1628-5-2015.

[0011] 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.

[0012] Wherein, X and / or Y are preferably selected from Al. When X and / or Y are selected from Al, it is more beneficial to reduce the formation of mold deposits. More preferably, X and Y are selected from Al to further reduce the formation of mold deposits.

[0013] 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.

[0014] 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-.

[0015] For example, the C3 to C8 cycloalkyl group is at least one of C3, C4, C5, C6, C7 or C8 cycloalkyl groups.

[0016] 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.

[0017] For example, aromatic groups include, but are not limited to, phenyl groups.

[0018] For example, n is selected from 2, 3 or 4.

[0019] For example, m is selected from 2, 3 or 4.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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, yielding di(or mono)alkyl-substituted hypophosphonate products.

[0024] 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.

[0025] In Formula III, R 1 and R 2 They can be the same, yet they can also be different.

[0026] 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.

[0027] 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-.

[0028] 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.

[0029] 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.

[0030] In Equation III, when R 1 and / or R 2 When selected from aromatic groups, the aromatic group can be phenyl.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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-.

[0035] 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.

[0036] 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.

[0037] In Equation IV, when R 3 When selected from aromatic groups, the aromatic group can be phenyl.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] In one embodiment, the molar ratio of di(or mono)alkyl-substituted sodium hypophosphite to the water-soluble salt is (0.5~8):1.

[0042] 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.

[0043] 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%.

[0044] In one embodiment, the metathesis reaction is carried out under an inert atmosphere. The inert atmosphere may be nitrogen or / or argon.

[0045] 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.

[0046] 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).

[0047] In some embodiments, the PBT composition contains bromine at a mass percentage of 7% to 15%, such as 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, or any two of the above ranges.

[0048] 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%.

[0049] 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.

[0050] In some embodiments, the brominated flame retardant includes at least one of brominated epoxy resin, decabromodiphenyl ethane, brominated polystyrene, polybrominated styrene, and pentabromobenzyl polyacrylate.

[0051] 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.

[0052] In some embodiments, the thermal decomposition temperature of the brominated epoxy resin is above 300°C, such as 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, or 370°C. In some embodiments, the brominated epoxy resin is phenol-terminated, for example, brominated epoxy resins include, but are not limited to, bisphenol A-terminated brominated epoxy resins.

[0053] In some embodiments, the thermal decomposition temperature of the brominated polystyrene is above 330°C, such as 330°C, 340°C, 350°C, 360°C, 370°C, or 380°C.

[0054] In some embodiments, the thermal decomposition temperature of the polybrominated styrene is above 350°C, such as 350°C, 360°C, 370°C, or 380°C.

[0055] In some embodiments, the thermal decomposition temperature of the polypentabromobenzyl acrylate is above 300°C, such as 300°C, 310°C, 320°C, 330°C, 340°C, or 350°C.

[0056] The thermal decomposition temperatures of the brominated epoxy resin, brominated polystyrene, polybrominated styrene, and pentabromobenzyl acrylate were determined by the following method: thermogravimetric analysis (TGA) was used, with a heating rate of 20℃ / min and a temperature range of 30-750℃.

[0057] Preferably, the PBT composition further includes the following components in parts by weight: 0.15 to 0.3 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 0.15 parts by weight, 0.2 parts by weight, 0.25 parts by weight, or 0.3 parts by weight.

[0058] 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.

[0059] In some embodiments, the PBT composition further includes the following component in parts by weight: 15 to 30 parts of glass fiber. For example, the glass fiber is 15 parts by weight, 20 parts by weight, 25 parts by weight, or 30 parts by weight.

[0060] In some embodiments, the glass fiber is an alkali-free glass fiber, the surface of which is treated with a silane coupling agent.

[0061] Other additives may be added to the PBT 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, lubricants, colorants, and antistatic agents.

[0062] 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.

[0063] 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).

[0064] 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.

[0065] 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.

[0066] The lubricant can be selected with reference to existing technologies, such as at least one of amide lubricants, stearate lubricants, ester lubricants, silicone lubricants, etc.

[0067] Specifically, the amide lubricants include, but are not limited to, at least one of erucamide, methyl bis-stearamide, or N,N-ethylene bis-stearamide; The stearate lubricants include, but are not limited to, at least one of calcium stearate, magnesium stearate, zinc stearate, or barium stearate; The ester lubricants include, but are not limited to, at least one of ethylene glycol stearate, glyceryl stearate, or pentaerythritol stearate; The silicone lubricant includes, but is not limited to, at least one of PE-based silicone masterbatch (e.g., silicone content 40 wt%~80 wt%), PP-based silicone masterbatch (e.g., silicone content 40 wt%~80 wt%), and SAN-based silicone masterbatch (e.g., silicone content 40 wt%~80 wt%).

[0068] 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.

[0069] 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.

[0070] In some embodiments, the other adjuvants are 0 to 3 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, or any range formed by two or more of these.

[0071] Secondly, this application provides a method for preparing a PBT composition, comprising the following steps: mixing and dispersing the component raw materials, melt extruding, granulating, and obtaining a PBT composition.

[0072] In one embodiment, melt extrusion is performed in a co-rotating twin-screw extruder when preparing the PBT composition.

[0073] In one embodiment, the melt extrusion meets the following conditions: zone 1 temperature 60-180℃, zone 2 temperature 230-260℃, zone 3 temperature 230-260℃, zone 4 temperature 210-240℃, zone 5 temperature 210-240℃, zone 6 temperature 210-240℃, zone 7 temperature 210-240℃, zone 8 temperature 210-240℃, zone 9 temperature 210-240℃, die head temperature 230-260℃; screw speed 200-800 rpm; screw length-to-diameter ratio 36:1-48:1; and feeding speed 450-800 kg / h.

[0074] Thirdly, this application provides a molded part formed from the PBT composition. 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.

[0075] The PBT composition can be applied in fields such as electronics, home appliances, and automobiles. In the electronics field, it can be used to manufacture components such as connectors and switch housings to prevent fires caused by short circuits. In home appliance components, it is often used in structural parts that require long-term heat resistance, such as microwave oven brackets and air conditioner fan blades. In the automotive industry, it is used in headlight bases, sensor housings, etc., to adapt to the high-temperature environment of the engine compartment.

[0076] Compared with the prior art, the beneficial effects of this application are as follows: by selecting PBT with a specific intrinsic viscosity as the matrix resin and adding specific amounts of dialkyl-substituted phosphinates, monoalkyl-substituted phosphinates and brominated flame retardants, the resulting composition has both good flame retardancy and low fouling during processing, making it suitable for application in the fields of electronics, home appliances, automobiles and the like. Detailed Implementation

[0077] 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.

[0078] 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: PBT resin 1: Grade GX111, intrinsic viscosity at 25℃ is 0.73 dL / g, manufacturer is Sinopec Yizheng Chemical Fiber Company.

[0079] PBT resin 2: Grade GX112, intrinsic viscosity at 25℃ is 0.82L / g, manufacturer is Sinopec Yizheng Chemical Fiber Company.

[0080] PBT resin 3: grade GL236, intrinsic viscosity at 25℃ is 1.2 dL / g, manufacturer is Sinopec Yizheng Chemical Fiber Company.

[0081] PBT resin 4: grade PBT GX110, intrinsic viscosity at 25℃ is 0.67 dL / g, manufacturer is Sinopec Yizheng Chemical Fiber Company.

[0082] 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.

[0083] 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).

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] Monoalkyl-substituted phosphinate 3: Aluminum phenylphosphinate, Hubei Chuyuebang New Material Technology Co., Ltd.

[0089] 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.

[0090] Al(H2PO2)3: Fujian Xin'an Technology, FR605.

[0091] Ammonium polyphosphate: Melamine-modified ammonium polyphosphate, CF-APP202C, Shifang Changfeng Chemical Co., Ltd.

[0092] Brominated flame retardant 1: Brominated epoxy resin, F 2100, ICL Israel.

[0093] Brominated flame retardant 2: Brominated polystyrene, SAYTEX HP 7010, Albemarle (ALB).

[0094] Brominated flame retardant 3: Decabromodiphenyl ethane, SAYTEX 8010, Albemarle (ALB).

[0095] Bromine-based flame retardant 4: Polybrominated styrene, SR-3010, Shandong Xurui New Materials Co., Ltd.

[0096] Fiberglass: ECS13-4.5-534A, China Jushi Co., Ltd.

[0097] Anti-dripping agent 1: Styrene-methyl methacrylate copolymer coated polytetrafluoroethylene, DB109, Shanghai Puxin Polymer Materials Co., Ltd.

[0098] Anti-dripping agent 2: Styrene-acrylonitrile random copolymer coated with polytetrafluoroethylene, SN80-SA7, Guangzhou Entropy Energy Innovation Materials Co., Ltd.

[0099] 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.

[0100] The following examples and comparative examples all provide a PBT composition, and their preparation methods include the following steps: According to the PBT composition formulations in Tables 1 and 2, the PBT resin was pre-dried and then added to a mixer along with other materials in the specified proportions. The mixture was stirred at 1000 rpm for 5 minutes and then removed. The stirred material was fed into the feed hopper of a co-rotating twin-screw extruder for melting, water-cooled, and pelletized to obtain the PBT composition. The twin-screw extruder process parameters were: zone 1 temperature 100℃, zone 2 temperature 250℃, zone 3 temperature 250℃, zone 4 temperature 240℃, zone 5 temperature 240℃, zone 6 temperature 240℃, zone 7 temperature 240℃, zone 8 temperature 240℃, zone 9 temperature 240℃, die head temperature 250℃, screw speed setting range 600 rpm, screw length-to-diameter ratio 36:1, and feeding speed 600 kg / h.

[0101] Table 1 Table 2 The PBT compositions of the above embodiments and comparative examples were subjected to the following performance tests: (1) Flame retardant performance: The PBT composition was injection molded into standard strips with a thickness of 1.5 mm or 0.8 mm, and the vertical burning flame retardant performance of the strips was tested according to UL94-2023 standard; (2) Mold fouling assessment: A KraussMaffei injection molding machine was used to inject a square plate, with an venting groove at the end of the plate. During injection, a small metal sheet was placed in the venting groove, and the decomposition gases after molding were cooled and gradually deposited on the metal sheet through the venting groove. Injection molding process: material temperature 280℃, injection speed 150mm / s, 300 molds were continuously injected, and the weight change of the metal sheet before and after injection was tested.

[0102] The test results are shown in Table 3.

[0103] Table 3 As can be seen from the above data, the PBT compositions in the above embodiments have good flame retardancy, such as the flame retardancy (thickness 1.5mm) reaching V-0 level; and they are not prone to mold fouling during processing, with the amount of mold fouling below 2.6mg.

[0104] In Comparative Example 1, the intrinsic viscosity of PBT was too high, which made it prone to shearing and heat generation during processing, resulting in excessive material decomposition and excessive mold fouling.

[0105] Comparative Examples 2 and 3, 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.

[0106] Comparative Examples 4 and 5, 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.

[0107] Comparative Examples 6 and 7, due to the use of other flame retardants to replace monohydrophosphinate, resulted in a higher amount of mold fouling during the processing of the compositions, and Comparative Example 7 showed a significant deterioration in flame retardancy.

[0108] A comparison of Examples 1 with Examples 5 and 6 shows that when the metal ions in dialkyl-substituted hypophosphite and monoalkyl-substituted hypophosphite are aluminum ions, there is less mold fouling.

[0109] 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 PBT composition, characterized in that, It includes the following components in parts by weight: 35-86 parts of PBT resin, 2.4-14 parts of dialkyl-substituted phosphinate, 0.15-3 parts of monoalkyl-substituted phosphinate, and 10-21 parts of brominated flame retardant; 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 intrinsic viscosity of the PBT resin at 25°C is ≤0.9 dL / g.

2. The PBT composition according to claim 1, characterized in that, The intrinsic viscosity of the PBT resin at 25°C is 0.6~0.75 dL / g.

3. The PBT composition according to claim 1, characterized in that, X and / or Y are selected from A1.

4. The PBT 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.

5. The PBT 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.

6. The PBT composition according to claim 1, characterized in that, The PBT composition contains 7% to 15% bromine by mass.

7. The PBT composition according to claim 1, characterized in that, The brominated flame retardant includes at least one of brominated epoxy resin, decabromodiphenyl ethane, brominated polystyrene, polybrominated styrene, and pentabromobenzyl polyacrylate.

8. The PBT composition according to claim 1, characterized in that, At least one of the following conditions must be met: (1) The PBT composition further includes the following components in parts by weight: 0.15 to 0.3 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; (2) The PBT composition further includes the following components in parts by weight: 15 to 30 parts of glass fiber.

9. The method for preparing the PBT 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 a PBT composition.

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

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