Polybutylene terephthalate resin composition, preparation method therefor and use thereof

Abstract

Disclosed are a polybutylene terephthalate resin composition, a preparation method therefor and a use thereof. The polybutylene terephthalate resin composition comprises the following components in parts by weight: 45-55 parts by weight of polybutylene terephthalate, 8-15 parts by weight of a halogen-free flame retardant, 1-6 parts by weight of a halogen-free synergist, 25-35 parts by weight of a glass fiber, 1-3 parts by weight of a physical covering agent, 0.1-0.6 parts by weight of a primary antioxidant, and 0.1-0.6 parts by weight of a secondary antioxidant; the polybutylene terephthalate resin composition further contains free silicone; and the total silicon content of the free silicone in the polybutylene terephthalate resin composition is 1-500 ppm. By means of the design of each component and the amount thereof, the polybutylene terephthalate resin composition provided by the present application simultaneously exhibits excellent color stability during injection molding, flame retardant properties, and mechanical properties.

Description

A polybutylene terephthalate resin composition, its preparation method and application Technical Field

[0001] This application relates to the field of engineering plastics technology, such as a polybutylene terephthalate resin composition, its preparation method, and its application. Background Technology

[0002] In modern electronic and electrical equipment, over 40% of the weight of components is made of flammable plastic insulation materials. Due to overheating, leakage, sparks, and aging, these devices may ignite the materials, causing fires and posing a significant threat to life and property. Furthermore, the incineration of brominated flame-retardant product waste produces toxic substances that cause lasting damage to the environment and human health. Therefore, the entire industry is trending towards halogen-free and environmentally friendly solutions.

[0003] Polybutylene terephthalate (PBT), as one of the five most commonly used engineering plastics, boasts outstanding advantages such as high temperature resistance, oil resistance, chemical corrosion resistance, electrical insulation properties, and short molding cycles. It has wide applications in numerous fields including electronics, automobiles, textiles, and precision instrument components. Currently, with the rapid development of the energy storage and new energy industries, the requirements for high temperature resistance and aging resistance of circuit connections and protection devices are becoming increasingly stringent. Furthermore, as people's living standards improve, their demands for materials are no longer limited to functionality but also include sensory experiences. However, polymer materials themselves undergo varying degrees of discoloration during high-temperature processing, and this discoloration problem is even more severe for thin-walled products requiring demanding injection molding processes. Currently, halogen-free flame-retardant reinforced PBT materials exhibit a color difference exceeding 2.0 between the first and second mold samples during injection molding, indicating poor color stability. Against this backdrop, higher requirements are placed on the color stability of PBT materials during injection molding, essentially controlling the product's appearance at the factory and its quality stability during use.

[0004] Currently, there is little research on the color stability of halogen-free flame-retardant reinforced PBT materials under injection molding. The research mainly focuses on halogenated flame-retardant PBT materials. For example, CN114517004A discloses a good-looking glass fiber reinforced flame-retardant PBT composition, its preparation method and application. Through the reasonable combination of flame retardant, titanium dioxide, antimony white and glass fiber, the bromine-based flame-retardant reinforced PBT composition has good flowability and small color difference during processing, while also having good mechanical properties and flame-retardant properties.

[0005] In order to keep pace with the trend of PBT compositions moving towards halogen-free and environmentally friendly products, it is necessary to design a halogen-free flame-retardant reinforced PBT composition with minimal color difference during processing and excellent tensile strength and flame-retardant properties. Summary of the Invention

[0006] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of the claims.

[0007] To address the shortcomings of related technologies, the purpose of this application is to provide a polybutylene terephthalate resin composition, its preparation method, and its application. Through the screening of various components and the synergistic compounding between components, the polybutylene terephthalate resin composition exhibits excellent color stability during injection molding, while also possessing good mechanical properties and flame retardant properties, enabling its application in many fields such as motors, new energy, and kitchen appliances.

[0008] To achieve this objective, the following technical solution is adopted in this application:

[0009] In a first aspect, this application provides a polybutylene terephthalate resin composition, wherein the polybutylene terephthalate resin composition comprises the following components in parts by weight:

[0010] 45-55 parts by weight of polybutylene terephthalate

[0011] 8-15 parts by weight of halogen-free flame retardant

[0012] Halogen-free synergist 1-6 parts by weight

[0013] 25-35 parts by weight of glass fiber

[0014] 1-3 parts by weight of physical masking agent

[0015] Primary antioxidant 0.1-0.6 parts by weight

[0016] 0.1-0.6 parts by weight of auxiliary antioxidant;

[0017] The polybutylene terephthalate resin composition also contains free organosilicon; the total silicon content of the free organosilicon in the polybutylene terephthalate resin composition is 1-500 ppm.

[0018] In this application, the free organosilicon may be derived from organosilicon compounds and / or polymeric organosilicon. When the free organosilicon is derived from organosilicon compounds, all organosilicon compounds are used as free organosilicon in the polybutylene terephthalate resin composition. When the free organosilicon is derived from polymeric organosilicon, the small molecule silicon-containing substances (molecular weight ≤ 800 g / mol) contained in the polymeric organosilicon are used as free organosilicon.

[0019] When free organosilicon originates from organosilicon compounds, the total silicon content of free organosilicon in the polybutylene terephthalate resin composition is lower than its theoretical value due to the loss of organosilicon compounds during processing.

[0020] In this application, the method for detecting free organosilicon is as follows: The polybutylene terephthalate resin composition is extracted with acetone solvent at 120℃ and 3MPa for 2 hours to separate the free organosilicon. After evaporating the organic solvent using an electric heating drying oven, 5mL of nitric acid and 2mL of hydrogen peroxide solution are added, and wet digestion is performed using a microwave digester to convert the extracted free organosilicon into inorganic silicon. The volume is then adjusted to 50mL with ultrapure water. The silicon content in the free organosilicon is then tested using the ICP-OES method. Each sample is tested twice, and the average value is taken as the final result.

[0021] The polybutylene terephthalate resin composition provided in this application is a halogen-free flame-retardant reinforced PBT composition, wherein the polybutylene terephthalate in the polybutylene terephthalate resin composition is 45-55 parts by weight, for example, 46 parts by weight, 47 parts by weight, 48 parts by weight, 49 parts by weight, 50 parts by weight, 51 parts by weight, 52 parts by weight, 53 parts by weight, or 54 parts by weight, etc.

[0022] The halogen-free flame retardant is 8-15 parts by weight, for example, it can be 8.5 parts by weight, 9 parts by weight, 9.5 parts by weight, 10 parts by weight, 10.5 parts by weight, 11 parts by weight, 11.5 parts by weight, 12 parts by weight, 12.5 parts by weight, 13 parts by weight, 13.5 parts by weight, 14 parts by weight or 14.5 parts by weight, etc.

[0023] The halogen-free synergist is 1-6 parts by weight, for example, it can be 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight, 3 parts by weight, 3.5 parts by weight, 4 parts by weight, 4.5 parts by weight, 5 parts by weight or 5.5 parts by weight, etc.

[0024] The glass fiber is 25-35 parts by weight, for example, 26 parts by weight, 27 parts by weight, 28 parts by weight, 29 parts by weight, 30 parts by weight, 31 parts by weight, 32 parts by weight, 33 parts by weight or 34 parts by weight, etc.

[0025] The physical masking agent is 1-3 parts by weight, for example, it can be 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 or 2.8 parts by weight, etc.

[0026] The total silicon content of the free organosilicon is 1-500 ppm, for example, it can be 1 ppm, 20 ppm, 50 ppm, 80 ppm, 100 ppm, 120 ppm, 150 ppm, 180 ppm, 200 ppm, 220 ppm, 250 ppm, 280 ppm, 300 ppm, 320 ppm, 350 ppm, 380 ppm, 400 ppm, 420 ppm, 450 ppm, 480 ppm or 500 ppm, etc.

[0027] The main antioxidant is 0.1-0.6 parts by weight, for example, it can be 0.15 parts by weight, 0.2 parts by weight, 0.25 parts by weight, 0.3 parts by weight, 0.35 parts by weight, 0.4 parts by weight, 0.45 parts by weight, 0.5 parts by weight or 0.55 parts by weight, etc.

[0028] The auxiliary antioxidant is present in amounts of 0.1-0.6 parts by weight, for example, 0.15 parts by weight, 0.2 parts by weight, 0.25 parts by weight, 0.3 parts by weight, 0.35 parts by weight, 0.4 parts by weight, 0.45 parts by weight, 0.5 parts by weight, or 0.55 parts by weight.

[0029] In this application, the primary antioxidant and the secondary antioxidant are of different types and have different effects. When used together, they have a synergistic effect. Furthermore, increasing the amount of primary antioxidant and secondary antioxidant can improve the color stability of the polybutylene terephthalate resin composition.

[0030] The following are optional technical solutions for this application, but are not intended to limit the technical solutions provided in this application. The purpose and beneficial effects of this application can be better achieved through the following optional technical solutions.

[0031] As an optional technical solution, the total silicon content of free organosilicon in the polybutylene terephthalate resin composition is 50-250 ppm, for example, it can be 60 ppm, 80 ppm, 100 ppm, 120 ppm, 140 ppm, 160 ppm, 180 ppm, 200 ppm, 220 ppm or 240 ppm, etc.

[0032] Optionally, the intrinsic viscosity of the polybutylene terephthalate at 25°C is 0.7-1.3 dL / g, for example, it can be 0.7 dL / g, 0.75 dL / g, 0.8 dL / g, 0.85 dL / g, 0.9 dL / g, 0.95 dL / g, 1 dL / g, 1.05 dL / g, 1.1 dL / g, 1.15 dL / g, 1.2 dL / g, or 1.25 dL / g.

[0033] In this application, the intrinsic viscosity is tested according to GB / T 14190-2017, the solvent is phenol and tetrachloroethane (the volume ratio of phenol to tetrachloroethane is 1:1), the dissolution temperature is 100°C, the dissolution time is 0.5h, the test temperature is 25°C, and the inner diameter of the viscosity tube is 0.77mm.

[0034] Optionally, the halogen-free flame retardant includes aluminum diethylphosphinate and / or aluminum hypophosphite.

[0035] Optionally, the halogen-free synergist includes melamine polyphosphate and / or melamine cyanurate.

[0036] Optionally, the diameter of the glass fiber is 7-17 μm, for example, it can be 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, 10 μm, 10.5 μm, 11 μm, 11.5 μm, 12 μm, 12.5 μm, 13 μm, 13.5 μm, 14 μm, 14.5 μm, 15 μm, 15.5 μm, 16 μm or 16.5 μm, etc.

[0037] Optionally, the chopped length of the glass fiber is 1-5 mm, for example, it can be 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, 2.2 mm, 2.5 mm, 2.8 mm, 3 mm, 3.2 mm, 3.5 mm, 3.8 mm, 4 mm, 4.2 mm, 4.5 mm or 4.8 mm, etc.

[0038] Optionally, the physical masking agent includes any one or a combination of at least two of titanium dioxide, zinc sulfide, calcium carbonate, or antimony trioxide. Titanium dioxide may be selected as an option.

[0039] In this application, titanium dioxide, zinc sulfide, calcium carbonate, and antimony trioxide are white fillers that physically cover the color of the polybutylene terephthalate resin composition. Among them, titanium dioxide has a better effect, and the more it is added, the smaller the color difference. However, excessive addition will lead to a decrease in the mechanical properties of the polybutylene terephthalate resin composition.

[0040] Optionally, the free organosilicon is derived from organosilicon, which includes any one or a combination of at least two of silanes, siloxanes, functional masterbatches, polysiloxanes, silicone rubber, or organosilicon derivatives.

[0041] Optionally, the silane includes any one or a combination of at least two of tetraphenylsilane, trimethylphenylsilane, or methyltriphenylsilane.

[0042] Optionally, the siloxane includes any one or a combination of at least two of dodecylcyclohexasiloxane, decamethylcyclopentasiloxane, or octamethylcyclotetrasiloxane.

[0043] Optionally, the functional masterbatch is a silicone masterbatch.

[0044] Optionally, the polysiloxane comprises dimethyl silicone oil and / or polymethylphenylsiloxane.

[0045] Optionally, the silicone rubber includes methyl vinyl silicone rubber and / or room temperature vulcanizing silicone rubber.

[0046] Optionally, the organosilicon derivative includes organomontmorillonite and / or organovermiculite.

[0047] Optionally, the primary antioxidant includes any one or a combination of at least two of hindered amine antioxidants, hindered phenolic antioxidants, or semi-hindered phenolic antioxidants, with semi-hindered phenolic antioxidants being an option.

[0048] Optionally, the hindered amine antioxidant includes poly[[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imino]-1,6-hexadiyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino]] and / or bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate.

[0049] In this application, the hindered amine antioxidant is exemplarily purchased from, but not limited to, BASF CHIMASSORB 944 FDL or Tianjin Lianlong New Material Co., Ltd. RIASORB UV-770DF.

[0050] Optionally, the hindered phenolic antioxidant includes any one or a combination of at least two of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, oxaloyl(diimino-2,1-ethylidene) propionate, or N,N'-(hexane-1,6-diyl)bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide].

[0051] In this application, the hindered phenolic antioxidants are, by way of example, purchased from, but not limited to, SONOX 1010, SONOX 1076, SONOX 1098 or SONOX 1027 from Sanfeng Chemical Co., Ltd. of Linyi City, Shandong Province.

[0052] Optionally, the semi-hindered phenolic antioxidant includes tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanuric acid and / or triethylene glycol ether-di(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate, optionally triethylene glycol ether-di(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate.

[0053] In this application, the semi-hindered phenolic antioxidant is exemplarily purchased from, but not limited to, antioxidant 1790 from Tianjin Lianlong New Materials Co., Ltd. or IRGANOX 245 from BASF.

[0054] Optionally, the auxiliary antioxidant includes any one or a combination of at least two of aryl phosphite antioxidants, alkyl phosphite antioxidants, or thioester antioxidants, with aryl phosphite antioxidants being an option.

[0055] Optionally, the aryl phosphite antioxidant includes tris(2,4-di-tert-butylphenyl) phosphite.

[0056] In this application, the aryl phosphite antioxidants are exemplarily purchased from, but not limited to, Mitutoyo Chemical's SONOX 168.

[0057] Optionally, the alkyl phosphite antioxidant includes any one or a combination of at least two of bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate, bis(2,4-dicumylphenyl) pentaerythritol diphosphate, or 3,9-bis(octadecoxy)-2,4,8,10-tetraoxa-3,9-diphosspiro[5.5]undecane.

[0058] In this application, the alkyl phosphite antioxidants are exemplarily purchased from, but not limited to, ADEKA PEP-36, Dover S-9228, or Foshan Yuansheng Chemical Co., Ltd. AP-618.

[0059] Optionally, the thioester antioxidant includes pentaerythritol tetra(3-lauryl thiopropionate) and / or distearate thiodipropionate, with pentaerythritol tetra(3-lauryl thiopropionate) being the preferred option.

[0060] In this application, the thioester antioxidants are exemplarily purchased from, but not limited to, Tianjin Lianlong New Materials Co., Ltd. RIANOX 412S or DSTDP.

[0061] Optionally, the mass ratio of the primary antioxidant to the secondary antioxidant is 1:(0.3-3) (e.g., 1:0.33, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8, 1:2, 1:2.2, 1:2.4, 1:2.6, or 1:2.8, etc.), or optionally 1:(1.5-2.5).

[0062] Optionally, the total mass of the primary antioxidant and the secondary antioxidant in the polybutylene terephthalate resin composition is 0.3-0.9 parts by weight (e.g., 0.35 parts by weight, 0.4 parts by weight, 0.45 parts by weight, 0.5 parts by weight, 0.55 parts by weight, 0.6 parts by weight, 0.65 parts by weight, 0.7 parts by weight, 0.75 parts by weight, 0.8 parts by weight, 0.85 parts by weight, or 0.9 parts by weight, etc.), or optionally 0.5-0.8 parts by weight (e.g., 0.52 parts by weight, 0.55 parts by weight, 0.58 parts by weight, 0.6 parts by weight, 0.62 parts by weight, 0.65 parts by weight, 0.68 parts by weight, 0.7 parts by weight, 0.72 parts by weight, 0.75 parts by weight, or 0.78 parts by weight, etc.).

[0063] Optionally, the components of the polybutylene terephthalate resin composition may further include a toughening agent.

[0064] Optionally, the toughening agent in the polybutylene terephthalate resin composition is ≤5 parts by weight, for example, it can be 0.2 parts by weight, 0.5 parts by weight, 0.8 parts by weight, 1 part by weight, 1.2 parts by weight, 1.5 parts by weight, 1.8 parts by weight, 2 parts by weight, 2.5 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, or 4.8 parts by weight.

[0065] Optionally, the toughening agent includes any one or a combination of at least two of ethylene-acrylate copolymer, ethylene-acrylate-glycidyl methacrylate copolymer, or ethylene-octene-glycidyl methacrylate copolymer.

[0066] Optionally, the components of the polybutylene terephthalate resin composition may further include a lubricant.

[0067] Optionally, the lubricant in the polybutylene terephthalate resin composition is ≤1 part by weight, for example, it can be 0.1 part by weight, 0.15 part by weight, 0.2 part by weight, 0.25 part by weight, 0.3 part by weight, 0.35 part by weight, 0.4 part by weight, 0.45 part by weight, 0.5 part by weight, 0.55 part by weight, 0.6 part by weight, 0.65 part by weight, 0.7 part by weight, 0.8 part by weight, or 0.9 part by weight.

[0068] Optionally, the lubricant includes any one or a combination of at least two of pentaerythritol stearate lubricants, oxidized polyethylene wax, or montan ester lubricants.

[0069] Secondly, this application provides a method for preparing a polybutylene terephthalate resin composition as described in the first aspect, the method comprising:

[0070] The polybutylene terephthalate resin composition is obtained by melt blending and extruding a mixture of polybutylene terephthalate, halogen-free flame retardant, halogen-free synergist, glass fiber, physical masking agent, silicone, primary antioxidant and secondary antioxidant.

[0071] Optionally, the melt-blended material may further include a lubricant and / or a toughening agent.

[0072] Optionally, the preparation method specifically includes the following steps:

[0073] (1) The halogen-free flame retardant and the halogen-free synergist are first mixed to obtain a first mixture; the polybutylene terephthalate, the physical masking agent, the organosilicon, the primary antioxidant, the auxiliary antioxidant, the lubricant, and the toughening agent are second mixed to obtain a second mixture;

[0074] (2) The first mixture, the second mixture and the glass fiber are melt-blended and then extruded to obtain the polybutylene terephthalate resin composition.

[0075] Optionally, the rotational speed of the first mixing is 700-900 rpm, for example, it can be 700 rpm, 720 rpm, 740 rpm, 760 rpm, 780 rpm, 800 rpm, 820 rpm, 840 rpm, 860 rpm or 880 rpm, etc.

[0076] Optionally, the first mixing time is 2-4 min, for example, it can be 2.2 min, 2.4 min, 2.6 min, 2.8 min, 3 min, 3.2 min, 3.4 min, 3.6 min or 3.8 min, etc.

[0077] Optionally, the rotational speed of the second mixing is 600-800 rpm, for example, it can be 620 rpm, 640 rpm, 660 rpm, 680 rpm, 700 rpm, 720 rpm, 740 rpm, 760 rpm or 780 rpm, etc.

[0078] Optionally, the second mixing time is 2-4 min, for example, it can be 2.2 min, 2.4 min, 2.6 min, 2.8 min, 3 min, 3.2 min, 3.4 min, 3.6 min or 3.8 min, etc.

[0079] Optionally, the melt blending is carried out in a screw extruder.

[0080] Optionally, the temperature of each temperature zone of the screw extruder is independently 200-260℃, for example, it can be 205℃, 210℃, 215℃, 220℃, 225℃, 230℃, 235℃, 240℃, 245℃, 250℃ or 255℃, etc.

[0081] Optionally, the screw speed of the screw extruder is 200-450 rpm, for example, it can be 220 rpm, 240 rpm, 260 rpm, 280 rpm, 300 rpm, 320 rpm, 340 rpm, 360 rpm, 380 rpm, 400 rpm, 420 rpm, or 440 rpm, etc.

[0082] Optionally, the extrusion process may further include a granulation step.

[0083] Thirdly, this application provides the use of the polybutylene terephthalate resin composition as described in the first aspect in low-voltage electrical appliances, household appliances, new energy batteries, or heat dissipation components.

[0084] Optionally, the polybutylene terephthalate resin composition is used in electric motor stators, energy storage connectors, junction boxes, or battery covers.

[0085] Compared with related technologies, this application has the following advantages:

[0086] The polybutylene terephthalate (PET) resin composition provided in this application, through the synergistic effect of physical hiding agents, free silicone, primary antioxidants, and secondary antioxidants, and through its interaction with other components of the PET resin composition, achieves excellent color stability, flame retardancy, and mechanical properties during injection molding. The PET resin composition provided in this application has a flame retardancy rating of V-0, a tensile strength ≥90 MPa, and a color stability ΔE ≤1.40 during injection molding.

[0087] After reading and understanding the detailed description, other aspects can be understood. Detailed Implementation

[0088] To facilitate understanding of this application, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of this application.

[0089] The sources of some components in the examples and comparative examples are as follows:

[0090] (1) PBT resin: purchased from Lanshan Tunhe, PBT TH6082, intrinsic viscosity is 0.82dL / g (25℃);

[0091] (2) Aluminum diethylphosphinic acid: purchased from Clariant, Germany, Exolit OP 1230;

[0092] (3) Melamine polyphosphate: purchased from Budenheim, Germany, BUDIT 3141;

[0093] (4) Glass fiber: The diameter of the single filament is 10μm and the length is 4mm. It was purchased from Taishan Glass Fiber Co., Ltd., HMG436S-10-4.0;

[0094] (5) Ethylene-methyl acrylate copolymer: purchased from DuPont, ELVALOY AC RESIN 1125;

[0095] (6) Lubricant (pentaerythritol stearate): purchased from Italian brand Falgi, PETS-AP;

[0096] (7) Physical masking agents:

[0097] Titanium dioxide, purchased from DuPont, R104;

[0098] Zinc sulfide, purchased from Guangdong Xinda New Material Technology Co., Ltd., MX622;

[0099] Antimony white, purchased from Changde Chenzhou Antimony Products Co., Ltd., S-05N;

[0100] (8) Organosilicon:

[0101] Silicone masterbatch, purchased from Dow Corning, MB50-002;

[0102] Tetraphenylsilane, purchased from Beijing Solarbio Technology Co., Ltd., YS156779;

[0103] Dodecylcyclohexasiloxane, purchased from Hubei Jusheng Technology Co., Ltd., JS2114;

[0104] Dimethyl silicone oil, purchased from Guangzhou Huigui Composite Materials Co., Ltd., O-SO4;

[0105] Methyl vinyl silicone rubber, purchased from Dongguan Shuang'ao Plastics Co., Ltd., 110-1;

[0106] Organo-montmorillonite, purchased from Beijing Yiwei Special Chemical Technology Development Co., Ltd., 1.3 PS;

[0107] (9) Main antioxidant:

[0108] Semi-hindered phenolic antioxidant, purchased from BASF, IRGANOX 245;

[0109] Hindered phenolic antioxidant, purchased from Mitutoyo Chemical, SONOX 1010;

[0110] Hindered phenolic antioxidant, purchased from Mitutoyo Chemical, SONOX 1027;

[0111] (10) Auxiliary antioxidants:

[0112] Aryl phosphite antioxidant, purchased from Mitutoyo Chemical, SONOX 168;

[0113] Alkyl phosphite antioxidant, purchased from ADEKA, PEP-36;

[0114] Thioester antioxidants, purchased from Rianon, DSTDP.

[0115] In the following examples and comparative examples, the method for detecting free organosilicon was as follows: The polybutylene terephthalate resin composition was extracted with acetone solvent at 120°C and 3 MPa for 2 hours to separate the free organosilicon. After evaporating the organic solvent using an electric heating drying oven, 5 mL of nitric acid and 2 mL of hydrogen peroxide solution were added, and wet digestion was performed using a microwave digester to convert the extracted free organosilicon into inorganic silicon. The volume was then adjusted to 50 mL with ultrapure water. The silicon content in the free organosilicon was accurately tested using the ICP-OES method. Each sample was tested twice, and the average value was taken as the final result.

[0116] Example 1

[0117] A polybutylene terephthalate resin composition, wherein the polybutylene terephthalate resin composition comprises the following components in parts by weight:

[0118] 50.4 parts by weight of polybutylene terephthalate

[0119] 11 parts by weight of aluminum diethylphosphinate

[0120] 3.5 parts by weight of melamine polyphosphate

[0121] 30 parts by weight of glass fiber

[0122] 2 parts by weight of ethylene-methyl acrylate copolymer

[0123] Pentaerythritol stearate 0.5 parts by weight

[0124] 2 parts by weight of titanium dioxide

[0125] 0.12 parts by weight of tetraphenylsilane

[0126] Primary antioxidant IRGANOX 245 0.2 parts by weight

[0127] 0.4 parts by weight of SONOX 168, an auxiliary antioxidant;

[0128] The preparation method of the polybutylene terephthalate resin composition includes the following steps:

[0129] (1) Aluminum diethylphosphinate and melamine polyphosphate were mixed at 800 rpm for 3 min to obtain the first mixture; polybutylene terephthalate, ethylene-methyl acrylate copolymer, pentaerythritol stearate, titanium dioxide, tetraphenylsilane, primary antioxidant IRGANOX 245 and secondary antioxidant SONOX 168 were mixed at 700 rpm for 3 min to obtain the second mixture;

[0130] (2) The first mixture, the second mixture and glass fiber are added to a twin-screw extruder. The screw speed of the twin-screw extruder is 300 rpm. The temperature of zone 1 is 215°C, zone 2 is 250°C, zone 3 is 245°C, zone 4 is 245°C, zone 5 is 245°C, zone 6 is 250°C, zone 7 is 250°C, zone 8 is 230°C, zone 9 is 230°C and zone 10 is 250°C. The above components are melt-blended and then extruded and granulated to obtain the polybutylene terephthalate resin composition.

[0131] Examples 2-18, Comparative Examples 1-6

[0132] A polybutylene terephthalate resin composition differs from Example 1 only in the type and / or amount (parts by weight) of the components, as shown in Tables 1, 2 and 3. The silicon content of free organosilicon in the polybutylene terephthalate resin composition is shown in the table below. The preparation method of the polybutylene terephthalate resin composition is the same as that of Example 1.

[0133]

[0134]

[0135]

[0136] Performance testing

[0137] (1) Flame retardant properties: The polybutylene terephthalate resin composition was tested according to the UL94 vertical burning standard;

[0138] (2) Tensile strength: The polybutylene terephthalate resin composition was tested according to standard ISO 527; the testing instrument was a universal testing machine (manufacturer: ZWICK, Germany, model: Z010), and the testing conditions were 10 mm / min;

[0139] (3) Color stability of injection molding: The polybutylene terephthalate resin composition was placed in the injection molding machine at an injection temperature of 270°C. 200 color samples were continuously injection molded. The color difference between the first and 200 color samples was measured using a colorimeter (X-rite Color-Eye 7000A, X-rite (Shanghai) Color Technology Co., Ltd.), and recorded as ΔE.

[0140] The polybutylene terephthalate resin compositions provided in Examples 1-18 and Comparative Examples 1-6 were tested according to the above method, and the test results are shown in Table 4.

[0141]

[0142] As shown in Table 4, this application achieves excellent color stability during injection molding of the polybutylene terephthalate resin composition through the compounding of physical masking agents, free organosilicon, primary antioxidants and auxiliary antioxidants, and synergistic effects with halogen-free flame retardants and halogen-free synergists. At the same time, it also has excellent flame retardant properties and tensile strength.

[0143] As shown in Examples 1-6, using organosilicon to increase the free organosilicon content in the polybutylene terephthalate (PET) resin composition is more beneficial for improving the color stability of the PET resin composition during injection molding. When the free organosilicon originates from organosilicon compounds, due to the loss of organosilicon compounds during processing, the total silicon content of free organosilicon in the PET resin composition is lower than its theoretical value.

[0144] As can be seen from Examples 1, 7 and 8, titanium dioxide can better improve the color stability of polybutylene terephthalate resin compositions during injection molding compared to other physical opacifiers.

[0145] As can be seen from Examples 1, 9 and 10, when the ratio of the main antioxidant to the auxiliary antioxidant is within a suitable range, the color stability of the polybutylene terephthalate resin composition during injection molding can be improved. When the ratio of the two is within an optional range, the color stability of the polybutylene terephthalate resin composition during injection molding can be further improved.

[0146] As can be seen from Examples 1, 11, and 12, controlling the total amount of primary and secondary antioxidants within the selectable range can maintain the color stability of the polybutylene terephthalate resin composition during injection molding at a high level; if the total amount of both is too small (Example 11) or too large (Example 12), the color stability of the polybutylene terephthalate resin composition during injection molding will deteriorate; in addition, if the total amount of primary and secondary antioxidants is too large, the risk of precipitation will increase during injection molding.

[0147] As can be seen from Examples 1 and 13-16, selecting appropriate primary and secondary antioxidants is more conducive to improving the color stability of polybutylene terephthalate resin compositions during injection molding.

[0148] As can be seen from Examples 1 and 17-18, controlling the silicon content of free organosilicon in the polybutylene terephthalate resin composition within a suitable range can further improve the color stability of the polybutylene terephthalate resin composition during injection molding.

[0149] As can be seen from the comparison of Example 1 and Comparative Examples 1-5, the color stability of the polybutylene terephthalate resin composition during injection molding can be improved through the combined action of physical masking agent, free organosilicon, main antioxidant and auxiliary antioxidant. All four are indispensable.

[0150] As can be seen from the comparison between Example 1 and Comparative Example 6, if too much physical masking agent is used, it will seriously degrade the mechanical properties of the polybutylene terephthalate resin composition.

Claims

1. A polybutylene terephthalate resin composition, comprising the following components in parts by weight: 45-55 parts by weight of polybutylene terephthalate 8-15 parts by weight of halogen-free flame retardant Halogen-free synergist 1-6 parts by weight 25-35 parts by weight of glass fiber 1-3 parts by weight of physical masking agent Primary antioxidant 0.1-0.6 parts by weight 0.1-0.6 parts by weight of auxiliary antioxidant; The polybutylene terephthalate resin composition also contains free organosilicon; The total silicon content of free organosilicon in the polybutylene terephthalate resin composition is 1-500 ppm.

2. The polybutylene terephthalate resin composition according to claim 1, wherein, The total silicon content of free organosilicon in the polybutylene terephthalate resin composition is 50-250 ppm; Optionally, the intrinsic viscosity of the polybutylene terephthalate at 25°C is 0.7-1.3 dL / g.

3. The polybutylene terephthalate resin composition according to claim 1, wherein, The halogen-free flame retardant includes aluminum diethylphosphinate and / or aluminum hypophosphite; Optionally, the halogen-free synergist includes melamine polyphosphate and / or melamine cyanurate.

4. The polybutylene terephthalate resin composition according to claim 1, wherein, The physical masking agent includes any one or a combination of at least two of titanium dioxide, zinc sulfide, calcium carbonate, or antimony trioxide, and may be selected from any one or a combination of at least two of titanium dioxide, zinc sulfide, or antimony trioxide, and may be selected from titanium dioxide. Optionally, the free organosilicon is derived from organosilicon, which includes any one or a combination of at least two of silanes, siloxanes, functional masterbatches, polysiloxanes, silicone rubber, or organosilicon derivatives.

5. The polybutylene terephthalate resin composition according to claim 4, wherein, The silane includes any one or a combination of at least two of tetraphenylsilane, trimethylphenylsilane or methyltriphenylsilane; Optionally, the siloxane includes any one or a combination of at least two of dodecylcyclohexasiloxane, decamethylcyclopentasiloxane, or octamethylcyclotetrasiloxane; Optionally, the functional masterbatch is a silicone masterbatch; Optionally, the polysiloxane comprises dimethyl silicone oil and / or polymethylphenylsiloxane; Optionally, the silicone rubber includes methyl vinyl silicone rubber and / or room temperature vulcanizing silicone rubber; Optionally, the organosilicon derivative includes organomontmorillonite and / or organovermiculite.

6. The polybutylene terephthalate resin composition according to claim 1, wherein, The primary antioxidant includes any one or a combination of at least two of hindered amine antioxidants, hindered phenolic antioxidants, or semi-hindered phenolic antioxidants, with semi-hindered phenolic antioxidants being an option. Optionally, the hindered amine antioxidant includes poly[[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imino]-1,6-hexadiyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino]] and / or bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate; Optionally, the hindered phenolic antioxidant includes any one or a combination of at least two of the following: pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, oxaloyl(diimino-2,1-ethylidene) propionate, or N,N'-(hexane-1,6-diyl)bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide]. Optionally, the semi-hindered phenolic antioxidant includes tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanuric acid and / or triethylene glycol ether-di(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate, optionally triethylene glycol ether-di(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate.

7. The polybutylene terephthalate resin composition according to claim 1, wherein, The auxiliary antioxidant includes any one or a combination of at least two of aryl phosphite antioxidants, alkyl phosphite antioxidants, or thioester antioxidants, with aryl phosphite antioxidants being optional. Optionally, the mass ratio of the primary antioxidant to the secondary antioxidant is 1:(0.3-3), or optionally 1:(1.5-2.5). Optionally, the total mass of the primary antioxidant and the secondary antioxidant in the polybutylene terephthalate resin composition is 0.3-0.9 parts by weight, and optionally 0.5-0.8 parts by weight.

8. The polybutylene terephthalate resin composition according to claim 7, wherein, The aryl phosphite antioxidants include tris(2,4-di-tert-butylphenyl) phosphite; Optionally, the alkyl phosphite antioxidant includes any one or a combination of at least two of bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate, bis(2,4-dicumylphenyl) pentaerythritol-diphosphite, or 3,9-bis(octadecoxy)-2,4,8,10-tetraoxa-3,9-diphosspiro[5.5]undecane; Optionally, the thioester antioxidant includes pentaerythritol tetra(3-lauryl thiopropionate) and / or distearate thiodipropionate, with pentaerythritol tetra(3-lauryl thiopropionate) being the preferred option.

9. The polybutylene terephthalate resin composition according to claim 1, wherein, The components of the polybutylene terephthalate resin composition also include a toughening agent; Optionally, the toughening agent in the polybutylene terephthalate resin composition is ≤5 parts by weight; Optionally, the toughening agent includes any one or a combination of at least two of ethylene-acrylate copolymer, ethylene-acrylate-glycidyl methacrylate copolymer, or ethylene-octene-glycidyl methacrylate copolymer.

10. The polybutylene terephthalate resin composition according to claim 1, wherein, The components of the polybutylene terephthalate resin composition also include a lubricant; Optionally, the lubricant in the polybutylene terephthalate resin composition is ≤1 part by weight; Optionally, the lubricant includes any one or a combination of at least two of pentaerythritol stearate lubricants, oxidized polyethylene wax, or montan ester lubricants.

11. A method for preparing a polybutylene terephthalate resin composition according to any one of claims 1-10, comprising: The polybutylene terephthalate resin composition is obtained by melt blending and extruding a mixture of polybutylene terephthalate, halogen-free flame retardant, halogen-free synergist, glass fiber, physical masking agent, silicone, primary antioxidant and secondary antioxidant.

12. The preparation method according to claim 11, wherein, The melt-blended material also includes lubricants and / or toughening agents; Optionally, the preparation method specifically includes the following steps: (1) The halogen-free flame retardant and the halogen-free synergist are first mixed to obtain a first mixture; the polybutylene terephthalate, the physical masking agent, the organosilicon, the primary antioxidant, the auxiliary antioxidant, the lubricant, and the toughening agent are second mixed to obtain a second mixture; (2) The first mixture, the second mixture and the glass fiber are melt-blended and then extruded to obtain the polybutylene terephthalate resin composition.

13. The preparation method according to claim 12, wherein, The rotational speed of the first mixing is 700-900 rpm; Optionally, the first mixing time is 2-4 minutes; Optionally, the rotational speed of the second mixing is 600-800 rpm; Optionally, the second mixing time is 2-4 minutes.

14. The preparation method according to claim 12, wherein, The melt blending is carried out in a screw extruder; Optionally, the temperature of each temperature zone of the screw extruder is independently 200-260°C; Optionally, the screw speed of the screw extruder is 200-450 rpm; Optionally, the extrusion process may further include a granulation step.

15. The use of a polybutylene terephthalate resin composition as described in any one of claims 1-10 in low-voltage electrical appliances, household appliances, new energy batteries or heat dissipation components.

Images