Polybutylene terephthalate resin composition, preparation method therefor, and use thereof

Abstract

The present application provides a polybutylene terephthalate resin composition, a preparation method therefor, and a use thereof. The polybutylene terephthalate resin composition comprises, in parts by weight, the following components: 45-56 parts by weight of polybutylene terephthalate, 10-16 parts by weight of a halogen-free flame retardant, 2-6 parts by weight of a halogen-free synergist, 25-35 parts by weight of glass fibers, 0.4-1.5 parts by weight of a stabilizer, and 0.3-2 parts by weight of a modifier. In the polybutylene terephthalate resin composition provided by the present application, individual components and the synergistic compounding between components are screened, such that the polybutylene terephthalate resin composition has both excellent glow wire performance and tensile strength, as well as a good injection molding appearance, and can be applied in the field of electronics and electrical engineering.

Description

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

[0001] This application belongs to the field of engineering plastics technology, specifically relating to 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 insulating 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. According to the IEC 60695 standard, for unattended electrical appliances with a rated current greater than 0.2A, they must meet the following requirements: UL 94V-0 rating, and no ignition should occur within 30 seconds of contact with a 750°C glow wire, or the burning time should be less than 5 seconds; that is, the glow wire ignition temperature (GWIT) must be higher than 775°C. The purpose of the glow wire test is to simulate the thermal stress effect of heat sources such as overheated components or overloaded resistors on surrounding parts in a short period of time, thereby demonstrating the stability of electronic and electrical products during operation.

[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, good electrical properties, and short molding cycles. It is widely used in numerous fields including electronics, electrical appliances, and home appliances. Consequently, the demand for products with high glow wire performance is constantly increasing. Furthermore, the incineration of solid waste containing brominated flame retardants produces toxic substances, causing persistent damage to the environment and human health. Therefore, PBT compositions are showing a trend towards halogen-free and environmentally friendly options. However, due to the acidic environment of halogen-free systems and their catalytic degradation effect on PBT, halogen-free flame-retardant reinforced PBT compositions suffer from issues such as poor tensile strength and a tendency to whiten during injection molding.

[0004] Currently, research on improving the glow wire properties of halogen-free flame-retardant reinforced PBT compositions is relatively limited. Research focuses primarily on the compounding of brominated and halogen-free flame retardants to achieve high glow wire performance. Furthermore, existing research on halogen-free flame-retardant reinforced PBT compositions largely concentrates on functionalization properties such as mechanical properties, flame retardancy, exudation, and warpage. Research on achieving a PBT composition that simultaneously possesses good tensile strength, no whitening during injection molding, and excellent glow wire properties is completely lacking. Therefore, there is an urgent need to design a halogen-free flame-retardant reinforced PBT composition that combines excellent tensile strength, glow wire properties, and injection molded appearance. Summary of the Invention

[0005] This application provides a polybutylene terephthalate resin composition, its preparation method, and its application. Through the screening of each component and the synergistic compounding between the components, the polybutylene terephthalate resin composition has both excellent glow wire properties and tensile strength, as well as good injection molding appearance, and can be applied in the field of electronics and electrical engineering.

[0006] To achieve this objective, the following technical solution is adopted in this application:

[0007] 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:

[0008] 45-56 parts by weight of polybutylene terephthalate

[0009] 10-16 parts by weight of halogen-free flame retardant

[0010] Halogen-free synergist 2-6 parts by weight

[0011] 25-35 parts by weight of glass fiber

[0012] Stabilizer 0.4-1.5 parts by weight, and

[0013] Modifier 0.3-2 parts by weight.

[0014] The reason for glow wire ignition failure in polybutylene terephthalate (PBT) lies in the generation of flammable gases. During thermal degradation, PBT produces a large amount of flammable butadiene gas. Due to its low ignition concentration, it is highly susceptible to ignition failure. One degradation pathway for PBT is a molecular degradation process dominated by the β-H transfer mechanism. In this process, PBT degrades to form terminal carboxyl and vinyl molecular chains. The terminal carboxyl groups further attack the ester groups, catalyzing the depolymerization reaction of the molecular chains. Furthermore, the acidic environment created by halogen-free flame retardants further accelerates this depolymerization process. This results in poor thermal stability of the halogen-free flame-retardant enhanced PBT composition, leading to the rapid generation of large amounts of butadiene gas, ultimately causing ignition failure and unsatisfactory glow wire performance.

[0015] Typically, the tensile strength of 30% glass fiber reinforced brominated flame-retardant PBT compositions is 120-140 MPa, while the tensile strength of 30% glass fiber reinforced halogen-free flame-retardant PBT compositions is only 90-100 MPa. The main reason behind this phenomenon is the acidic environment created by the halogen-free flame retardant: under high-temperature extrusion processing conditions, the ester bonds in PBT break, forming more terminal carboxyl groups. These terminal carboxyl groups further attack the ester groups. Simultaneously, the acidic environment provides a large number of hydrogen ions. Since the ester bonds are weak points in the PBT molecular structure, they are highly susceptible to electrophilic attack by hydrogen ions, catalyzing and accelerating the degradation process of PBT, resulting in lower tensile strength in halogen-free flame-retardant reinforced PBT resins.

[0016] Burning and whitening during injection molding are related to many factors, including materials, injection molding process, mold design, and molding equipment. Regarding materials, if the matrix material itself has poor thermal stability, it is prone to decomposition during injection molding, generating a large amount of gas. This gas is compressed during injection molding, generating high temperatures and causing the product to burn and turn white. For halogen-free flame-retardant reinforced PBT compositions, acidic halogen-free flame retardants have a catalytic degradation effect on PBT.

[0017] In summary, PBT generates terminal carboxyl groups during pyrolysis / hydrolysis, and the acidic environment provided by the terminal carboxyl groups and halogen-free flame retardants further accelerates the degradation process. This leads to problems with the short-term performance (glow wire, tensile strength) and injection molding performance (scorching and whitening) of halogen-free flame-retardant reinforced PBT compositions. Therefore, this application uses stabilizers to reduce the acidity of the terminal carboxyl groups and halogen-free flame retardants, thereby reducing PBT degradation and lowering the content of initial terminal carboxyl groups in the system. For those molecular chains that have already degraded, reactive modifiers are used to quench the activity of the terminal carboxyl groups in the PBT composition, or to connect the terminal carboxyl groups to each other, acting as a "bridging" agent. This slows down the pyrolysis / hydrolysis process caused by acid catalysis in the PBT composition, resulting in products with excellent glow wire performance, good tensile strength, and superior injection molding appearance.

[0018] The polybutylene terephthalate (PBT) resin composition provided in this application is a high glow wire halogen-free flame-retardant reinforced PBT composition. The PBT resin composition contains 45-56 parts by weight of PBT, for example, 45 parts by weight, 45.5 parts by weight, 46 parts by weight, 46.5 parts by weight, 47 parts by weight, 47.5 parts by weight, 48 parts by weight, 48.5 parts by weight, 49 parts by weight, 49.5 parts by weight, 50 parts by weight, 50.5 parts by weight, 51 parts by weight, 51.5 parts by weight, 52 parts by weight, 52.5 parts by weight, 53 parts by weight, 53.5 parts by weight, 54 parts by weight, 54.5 parts by weight, 55 parts by weight, 55.5 parts by weight, etc.

[0019] The halogen-free flame retardant is 10-16 parts by weight, for example, 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, 14.5 parts by weight, 15 parts by weight, 15.5 parts by weight, 16 parts by weight, etc.

[0020] The halogen-free synergist is present in 2-6 parts by weight, for example, 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, 3.4 parts by weight, 3.6 parts by weight, 3.8 parts by weight, 4 parts by weight, 4.2 parts by weight, 4.4 parts by weight, 4.6 parts by weight, 4.8 parts by weight, 5 parts by weight, 5.2 parts by weight, 5.4 parts by weight, 5.6 parts by weight, 5.8 parts by weight, etc.

[0021] The glass fiber is 25-35 parts by weight, for example, 25 parts by weight, 25.5 parts by weight, 26 parts by weight, 26.5 parts by weight, 27 parts by weight, 27.5 parts by weight, 28 parts by weight, 28.5 parts by weight, 29 parts by weight, 29.5 parts by weight, 30 parts by weight, 30.5 parts by weight, 31 parts by weight, 31.5 parts by weight, 32 parts by weight, 32.5 parts by weight, 33 parts by weight, 33.5 parts by weight, 34 parts by weight, 34.5 parts by weight, etc.

[0022] The stabilizer is 0.4-1.5 parts by weight, for example, it can be 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, 0.9 parts by weight, 0.95 parts by weight, 1.0 parts by weight, 1.05 parts by weight, 1.1 parts by weight, 1.15 parts by weight, 1.2 parts by weight, 1.25 parts by weight, 1.3 parts by weight, 1.35 parts by weight, 1.4 parts by weight, 1.45 parts by weight, etc.

[0023] The modifier is 0.3-2 parts by weight, for example, it can be 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, 0.9 parts by weight, 0.95 parts by weight, 1 part by weight, 1.05 parts by weight, 1.1 parts by weight, 1.15 parts by weight, 1.2 parts by weight, 1.25 parts by weight, 1.3 parts by weight, 1.35 parts by weight, 1.4 parts by weight, 1.45 parts by weight, 1.5 parts by weight, 1.55 parts by weight, 1.6 parts by weight, 1.65 parts by weight, 1.7 parts by weight, 1.75 parts by weight, 1.8 parts by weight, 1.85 parts by weight, 1.9 parts by weight, 1.95 parts by weight, etc.

[0024] The following are preferred technical solutions of 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 preferred technical solutions.

[0025] As a preferred technical solution, 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, 1.25 dL / g, etc.

[0026] 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.

[0027] Preferably, the halogen-free flame retardant comprises aluminum diethylphosphinate and / or aluminum hypophosphite.

[0028] Preferably, the halogen-free synergist comprises melamine polyphosphate and / or melamine cyanurate.

[0029] Preferably, 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, 16.5 μm, etc.

[0030] Preferably, 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, 4.8 mm, etc.

[0031] Preferably, the stabilizer comprises a first stabilizer and / or calcium stearate; the first stabilizer comprises any one of magnesium oxide, calcium oxide, or a metal hydroxide.

[0032] Preferably, the metal hydroxide includes any one or a combination of at least two of magnesium hydroxide, calcium hydroxide, sodium hydroxide, aluminum hydroxide, zinc hydroxide, or iron hydroxide.

[0033] Preferably, the stabilizer comprises a combination of the first stabilizer and the calcium stearate.

[0034] Preferably, the mass ratio of the first stabilizer to calcium stearate in the stabilizer is 1:(0.5-5), for example, it can be 1:0.8, 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, etc., and more preferably 1:(2-3), for example, it can be 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9, etc.

[0035] In this application, the calcium stearate and polybutylene terephthalate resin composition system has good compatibility. The first stabilizer can better reduce the acidity of the terminal carboxyl groups and halogen-free flame retardants. Through the synergistic compounding of calcium stearate and the first stabilizer, the degradation of PBT can be reduced, so that the product has excellent glow wire performance, good tensile strength and excellent injection molding appearance.

[0036] Preferably, the modifier comprises carbodiimide monomer and / or polycarbodiimide, more preferably polycarbodiimide.

[0037] Preferably, the NCN (-N=C=N-) content of the polycarbodiimide is ≥10%, for example, it can be 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, 15.5%, 16%, 16.5%, 17%, 17.5%, 18%, etc.

[0038] Preferably, the mass ratio of the stabilizer to the modifier is (0.3-3):1, for example, it can be 0.35:1, 0.4:1, 0.45:1, 0.5:1, 0.55:1, 0.6:1, 0.68:1, 0.78:1, 0.88:1, 0.98:1, 1.08:1, 1.18:1, 1.28:1, 1.48:1, 1.68:1, 1.88:1, 2.08:1, 2.28:1, 2.48:1, 2.68:1, 2.88... :1, etc., further preferred (0.6-1.8):1, for example, can be 0.65:1, 0.7:1, 0.75:1, 0.8:1, 0.85:1, 0.9:1, 0.95:1, 1:1, 1.05:1, 1.1:1, 1.15:1, 1.2:1, 1.25:1, 1.3:1, 1.35:1, 1.4:1, 1.45:1, 1.5:1, 1.55:1, 1.6:1, 1.65:1, 1.7:1, 1.75:1, etc.

[0039] Preferably, the components of the polybutylene terephthalate resin composition further include a lubricant.

[0040] Preferably, the lubricant includes any one or a combination of at least two of ester-based lubricants, hydrocarbon-based lubricants, or silicone-based lubricants.

[0041] Preferably, the ester lubricant includes pentaerythritol stearate; exemplaryly, the pentaerythritol stearate may be purchased from, but is not limited to, Shandong Ruijie New Materials PETS, Italian Faji PETS-AP, Emory Oils & Chemicals LOXIOL P 861 / 3.5, etc.

[0042] Preferably, the hydrocarbon lubricant includes oxidized polyethylene wax.

[0043] Preferably, the silicone lubricant can be purchased. For example, the silicone lubricant can be purchased from, but is not limited to, Zhejiang Jiahua Jinghua Co., Ltd. GT-300.

[0044] Preferably, the lubricant in the polybutylene terephthalate resin composition is 0.2-1 parts by weight, for example, 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, 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, 0.9 parts by weight, 0.95 parts by weight, etc.

[0045] Preferably, the components of the polybutylene terephthalate resin composition further include an antioxidant.

[0046] Preferably, the antioxidant includes any one or a combination of at least two of the following: hindered phenolic antioxidants, semi-hindered phenolic antioxidants, phosphite antioxidants, or thioester antioxidants.

[0047] Preferably, the antioxidant in the polybutylene terephthalate resin composition is 0.1-0.5 parts by weight, for example, 0.1 parts by weight, 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, etc.

[0048] Secondly, this application provides a method for preparing a polybutylene terephthalate resin composition as described in the first aspect, the method comprising:

[0049] The polybutylene terephthalate (PET), halogen-free flame retardant, halogen-free synergist, stabilizer, modifier and glass fiber are melt-blended and then extruded to obtain the PET resin composition.

[0050] Preferably, the melt-blended material further includes a lubricant and / or an antioxidant.

[0051] Preferably, the preparation method specifically includes the following steps:

[0052] (1) The halogen-free flame retardant and the halogen-free synergist are first mixed to obtain a first mixture; the polybutylene terephthalate, the stabilizer, the modifier, the optional lubricant and the optional antioxidant are second mixed to obtain a second mixture;

[0053] (2) The first mixture, the second mixture and the glass fiber are melt-blended and then extruded to obtain the polybutylene terephthalate resin composition.

[0054] Preferably, 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, 880 rpm, etc.

[0055] Preferably, 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, 3.8 min, etc.

[0056] Preferably, 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, 780 rpm, etc.

[0057] Preferably, 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, 3.8 min, etc.

[0058] Preferably, the melt blending is carried out in a screw extruder.

[0059] Preferably, 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℃, 255℃, etc.

[0060] Preferably, 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, 440 rpm, etc.

[0061] Preferably, the extrusion process further includes a granulation step.

[0062] Thirdly, this application provides the use of the polybutylene terephthalate resin composition as described in the first aspect in electronic components, low-voltage electrical appliances, and heat dissipation components.

[0063] Compared with the prior art, this application has the following beneficial effects:

[0064] The polybutylene terephthalate resin composition provided in this application, through the design of its components and the synergistic compounding between them, has excellent glow wire properties and tensile strength, as well as a good appearance; wherein, the GWIT of the polybutylene terephthalate resin composition is 775-850℃, the tensile strength is 100-115MPa, the whitening grade of the injection molding appearance is 0-1, and the flame retardant grade is V-0. Attached Figure Description

[0065] Figure 1 is a chart showing the evaluation criteria for a whitening grade of 0 in the appearance of polybutylene terephthalate resin compositions.

[0066] Figure 2 is a chart showing the evaluation criteria for the whitening grade of the polybutylene terephthalate resin composition as Grade 1.

[0067] Figure 3 is a chart showing the evaluation criteria for a whitening grade of 2 in the appearance of polybutylene terephthalate resin composition.

[0068] Figure 4 is a criterion chart for judging the whitening grade of the polybutylene terephthalate resin composition as grade 3. Detailed Implementation

[0069] The technical solution of this application will be further described below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of this application and should not be construed as specific limitations thereof.

[0070] The sources of some components in the following examples and comparative examples are as follows:

[0071] (1) Polybutylene terephthalate: purchased from Lanshan Tunhe, PBT TH6082, intrinsic viscosity is 0.82 dL / g (25℃);

[0072] (2) Aluminum diethylphosphinic acid: purchased from Clariant, Germany, Exolit OP 1230;

[0073] (3) Melamine polyphosphate: purchased from Budenheim, Germany, BUDIT 3141;

[0074] (4) Glass fiber: monofilament diameter is 10μm, chopped length is 4mm, purchased from Taishan Glass Fiber Co., Ltd., HMG436S-10-4.0;

[0075] (5) Magnesium oxide: purchased from Kyowa Chemical Industry Co., Ltd., KYOWAMAG 150;

[0076] (6) Calcium stearate: purchased from Bailihe Chemical (Zhongshan) Co., Ltd., BS-3818;

[0077] (7) Carbodiimide monomer: purchased from Rasig, Germany, Stabilizer 7000;

[0078] (8) Polycarbodiimide: purchased from Langyi Technology, Hymax213;

[0079] (9) Lubricant: Ester lubricant, purchased from Italian brand PETS-AP;

[0080] (10) Antioxidant: Hindered phenolic antioxidant, purchased from Mitutoyo Chemical, SONOX 1010;

[0081] (11) Magnesium hydroxide: purchased from Jiangsu Aitemag Flame Retardant Materials Co., Ltd., Aitemag 55ZA2;

[0082] (12) Calcium oxide: purchased from Hangzhou Wenjian Calcium Industry Co., Ltd.

[0083] Example 1

[0084] A polybutylene terephthalate resin composition, wherein the polybutylene terephthalate resin composition comprises the following components in parts by weight:

[0085] 54.6 parts by weight of polybutylene terephthalate (PET)

[0086] 10 parts by weight of aluminum diethylphosphinate

[0087] 6 parts by weight of melamine polyphosphate

[0088] 25 parts by weight of glass fiber

[0089] 1.5 parts by weight of magnesium oxide,

[0090] 2 parts by weight of polycarbodiimide

[0091] Lubricant PETS-AP 0.6 parts by weight, and

[0092] Antioxidant SONOX 10100.3 parts by weight.

[0093] The preparation method of the polybutylene terephthalate resin composition includes the following steps:

[0094] (1) Mix aluminum diethylphosphinate and melamine polyphosphate at 800 rpm for 3 min to obtain the first mixture; mix polybutylene terephthalate, magnesium oxide, polycarbodiimide, lubricant PETS-AP and antioxidant SONOX 1010 at 700 rpm for 3 min to obtain the second mixture;

[0095] (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.

[0096] Examples 2-10, Comparative Examples 1-6

[0097] 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 preparation method of the polybutylene terephthalate resin composition is the same as that of Example 1.

[0098]

[0099]

[0100]

[0101] Performance testing

[0102] (1) Flame retardant properties: The polybutylene terephthalate resin composition was tested according to the UL 94 vertical burning standard;

[0103] (2) Glow wire test (GWIT): The polybutylene terephthalate resin composition was tested at different temperatures according to standard IEC 60695-2-2013;

[0104] (3) 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;

[0105] (4) Whitening assessment method: Using KraussMaffei machine (model CX 160-750), injection molding process: material temperature 275°C, injection speed medium to high speed, continuous injection of 50 molds, visually observe the whitening phenomenon of the last 5 molds, and evaluate the appearance of the polybutylene terephthalate resin composition according to Figure 1, Figure 2, Figure 3 and Figure 4; if the appearance is as shown in Figure 1, the whitening level is 0, indicating no whitening; if the appearance is as shown in Figure 2, the whitening level is 1, indicating slight whitening; if the appearance is as shown in Figure 3, the whitening level is 2, indicating moderate whitening; if the appearance is as shown in Figure 4, the whitening level is 3, indicating severe whitening.

[0106]

[0107] According to the performance test data in Table 4, this application obtains a high-performance polybutylene terephthalate resin composition with high tensile strength, high GWIT and good injection molding appearance by designing and compounding stabilizers and modifiers, and by synergizing with halogen-free flame retardants and halogen-free synergists. The GWIT of the polybutylene terephthalate resin composition is ≥775℃.

[0108] As can be seen from the comparison between Example 2 and Example 4, using magnesium oxide and calcium stearate together as stabilizers can further improve the GWIT of the polybutylene terephthalate resin composition.

[0109] As can be seen from the comparison between Example 2 and Example 5, compared with carbodiimide monomer, using polycarbodiimide as a modifier can further improve the tensile strength and injection molding appearance of polybutylene terephthalate resin composition.

[0110] This application controls the mass ratio of stabilizer to modifier within a suitable range and combines it with other components to give the polybutylene terephthalate resin composition excellent GWIT, tensile strength and injection molding appearance. In Example 6, the mass ratio of stabilizer to modifier is less than 0.6:1, and in Example 7, the mass ratio of stabilizer to modifier is greater than 1.8:1, resulting in a deterioration in the injection molding appearance of the polybutylene terephthalate resin composition.

[0111] This application achieves excellent GWIT, tensile strength, and injection molding appearance in polybutylene terephthalate resin compositions by controlling the mass ratio of the first stabilizer to calcium stearate within a suitable range and compounding it with other components. In Example 8, the mass ratio of the first stabilizer to calcium stearate is less than 1:3, and in Example 9, the mass ratio of the first stabilizer to calcium stearate is greater than 1:2. The GWIT and tensile strength of the polybutylene terephthalate resin compositions are worse than those in Example 4.

[0112] This application, by screening specific types of stabilizers, enables polybutylene terephthalate resin compositions to have high tensile strength, high GWIT, and good injection molding appearance. However, Example 10 uses calcium oxide as a stabilizer, which has relatively weak reactivity, resulting in poor GWIT in the polybutylene terephthalate resin composition.

[0113] This application, through the design of modifiers and stabilizers, and their compounding with other components, enables polybutylene terephthalate (PET) resin compositions to possess excellent GWIT, tensile strength, and injection molding appearance. Comparative Example 1, without modifiers and stabilizers, exhibits a GWIT of only 750°C and a poor injection molding appearance. Compared to Comparative Example 1, Comparative Examples 2, 3, and 6, which used stabilizers or modifiers alone, showed no significant improvement in GWIT, but achieved better injection molding appearances. This is because stabilizers neutralize the acidity of the PET resin composition, thereby reducing its degradation under acid catalysis and decreasing the generation of small molecule gases. Modifiers can reconnect the broken small molecule chains in the PET resin composition, potentially reversing the degradation process of PET to some extent and further reducing the generation of small molecule gases, thus contributing to improved injection molding appearance. In Comparative Example 4, the amount of modifier was too high, resulting in deterioration of the GWIT, tensile strength, and injection molding appearance of the polybutylene terephthalate resin composition. In Comparative Example 5, the amount of stabilizer was too high, resulting in deterioration of the GWIT, tensile strength, and injection molding appearance of the polybutylene terephthalate resin composition.

[0114] The applicant declares that this application illustrates the polybutylene terephthalate resin composition, its preparation method, and its application through the above embodiments. However, this application is not limited to the above embodiments, meaning that this application does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this application, equivalent substitutions of raw materials, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection and disclosure scope of this application.

Claims

A polybutylene terephthalate resin composition comprising, by weight, the following components: 45-56 parts by weight of polybutylene terephthalate 10-16 parts by weight of halogen-free flame retardant Halogen-free synergist 2-6 parts by weight 25-35 parts by weight of glass fiber Stabilizer 0.4-1.5 parts by weight, and Modifier 0.3-2 parts by weight. According to claim 1, the polybutylene terephthalate resin composition, wherein, The modifier includes carbodiimide monomers and / or polycarbodiimide, with polycarbodiimide being more preferred. According to claim 1, the polybutylene terephthalate resin composition, wherein, The mass ratio of the stabilizer to the modifier is (0.3-3):1, and more preferably (0.6-1.8):

1. According to claim 1, the polybutylene terephthalate resin composition, wherein, The halogen-free flame retardant includes aluminum diethylphosphinate and / or aluminum hypophosphite; Preferably, the halogen-free synergist comprises melamine polyphosphate and / or melamine cyanurate. According to claim 1, the polybutylene terephthalate resin composition, wherein, The stabilizer includes a first stabilizer and / or calcium stearate; the first stabilizer includes any one of magnesium oxide, calcium oxide, or a metal hydroxide. Preferably, the metal hydroxide includes any one or a combination of at least two of magnesium hydroxide, calcium hydroxide, sodium hydroxide, aluminum hydroxide, zinc hydroxide, or iron hydroxide. According to claim 5, the polybutylene terephthalate resin composition, wherein, The stabilizer comprises a combination of the first stabilizer and the calcium stearate; Preferably, the mass ratio of the first stabilizer to calcium stearate in the stabilizer is 1:(0.5-5), and more preferably 1:(2-3). According to claim 1, the polybutylene terephthalate resin composition, wherein, The components of the polybutylene terephthalate resin composition also include a lubricant; Preferably, the lubricant includes any one or a combination of at least two of ester-based lubricants, hydrocarbon-based lubricants, or silicone-based lubricants; Preferably, the lubricant in the polybutylene terephthalate resin composition is 0.2-1 parts by weight. According to claim 1, the polybutylene terephthalate resin composition, wherein, The components of the polybutylene terephthalate resin composition also include antioxidants; Preferably, the antioxidant includes any one or a combination of at least two of the following: hindered phenolic antioxidants, semi-hindered phenolic antioxidants, phosphite antioxidants, or thioester antioxidants; Preferably, the antioxidant in the polybutylene terephthalate resin composition is 0.1-0.5 parts by weight. A method for preparing a polybutylene terephthalate resin composition as described in any one of claims 1-8, comprising: The polybutylene terephthalate (PET), halogen-free flame retardant, halogen-free synergist, stabilizer, modifier and glass fiber are melt-blended and then extruded to obtain the PET resin composition. According to the preparation method of claim 9, wherein, The melt-blended materials also include lubricants and / or antioxidants. According to claim 9, 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 stabilizer, the modifier, the lubricant (optionally), and the antioxidant (optionally) 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. According to the preparation method of claim 11, wherein, The rotational speed of the first mixing is 700-900 rpm; Preferably, the first mixing time is 2-4 minutes; Preferably, the rotational speed of the second mixing is 600-800 rpm; Preferably, the second mixing time is 2-4 minutes; Preferably, the melt blending is carried out in a screw extruder; Preferably, the temperature of each temperature zone of the screw extruder is independently 200-260°C; Preferably, the screw speed of the screw extruder is 200-450 rpm; Preferably, the extrusion process further includes a granulation step. The use of a polybutylene terephthalate resin composition as described in any one of claims 1-8 in electronic components, low-voltage electrical appliances and heat dissipation components.

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