A polybutylene terephthalate resin composition, a method for preparing the same, and an application thereof

Abstract

The application provides a polybutylene terephthalate resin composition and a preparation method and application thereof, the polybutylene terephthalate resin composition comprises the following components in parts by weight: polybutylene terephthalate 45-56 parts by weight, halogen-free flame retardant 10-16 parts by weight, halogen-free synergist 2-6 parts by weight, glass fiber 25-35 parts by weight, stabilizer 0.4-1.5 parts by weight and modifier 0.3-2 parts by weight. The polybutylene terephthalate resin composition provided by the application has excellent hot wire performance and tensile strength, and good injection molding appearance, and can be applied to the field of electronics and electrical appliances.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of engineering plastics, and particularly relates to a polybutylene terephthalate resin composition and a preparation method and application thereof. BACKGROUND

[0002] In modern electronic and electrical equipment, more than 40% of the components are made of flammable plastic insulation materials. Due to overheating, electric leakage, sparking and aging, these devices may ignite the material and cause a fire, causing great damage to people's life and property safety. According to IEC60695 standards, for unattended electrical appliances, if the rated current is greater than 0.2A, it must meet: reach UL94V-0 level, and no fire phenomenon appears within 30s of 750℃ glowing wire contacting the material or the burning time is less than 5s, that is, the glowing wire ignition temperature (GWIT) is higher than 775℃. The purpose of the glowing wire test is to simulate the influence of heat stress formed by heat sources such as overheated components or overload resistors on the surrounding parts in a short time, so as to reflect the stability of electronic and electrical products during operation.

[0003] Polybutylene terephthalate (PBT) is one of the five commonly used engineering plastics, which has the outstanding advantages of high temperature resistance, oil resistance, chemical corrosion resistance, good electrical performance and short molding cycle, and is widely used in many fields such as electronics and electrical appliances, household appliances, etc. Therefore, the demand for high glowing wire performance of products is increasing. In addition, when solid waste containing bromine-based flame retardants is incinerated, toxic substances will be produced, causing persistent damage to the environment and human health, so PBT compositions show a trend of developing towards halogen-free and environmentally friendly. However, due to the acidic environment of halogen-free system and the catalytic degradation of PBT, halogen-free flame-retardant reinforced PBT compositions have the problems of poor tensile strength, easy whitening during injection molding and other aspects.

[0004] At present, the related research on improving the glowing wire performance of halogen-free flame-retardant reinforced PBT compositions is relatively limited, and the research focus is mainly on the compounding of bromine-based and halogen-free flame retardants to obtain high glowing wire performance. In addition, the existing halogen-free flame-retardant reinforced PBT compositions are more focused on the research of mechanical, flame-retardant, precipitation, warping and other functional properties, and the research on PBT compositions with good tensile strength, no injection whitening problem and good glowing wire performance is still a blank. Therefore, it is urgent to design a halogen-free flame-retardant reinforced PBT composition with excellent tensile strength, glowing wire performance and injection appearance. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide a polybutylene terephthalate resin composition, a preparation method and application thereof, which have excellent hot-wire performance and tensile strength, and good injection molding appearance by screening of various components and synergistic compounding between components, and can be applied in the field of electronics and electrical appliances.

[0006] To achieve this purpose, the present application adopts the following technical solutions:

[0007] In a first aspect, the present application provides a polybutylene terephthalate resin composition, which comprises the following components by weight:

[0008]

[0009] The reason for the ignition failure of polybutylene terephthalate (PBT) is the generation of flammable gas. When PBT is thermally degraded, a large amount of flammable butadiene gas is generated. Because the ignition concentration is low, the ignition failure condition occurs easily. For the thermal degradation process of PBT, one degradation pathway is a molecular degradation process dominated by β-H transfer mechanism. In this process, PBT is degraded to form carboxyl-terminated and vinyl-terminated molecular chains. The carboxyl-terminated groups further attack the ester groups, thereby catalyzing the depolymerization reaction of the molecular chains. In addition, the acidic environment created by the halogen-free flame retardant further accelerates this depolymerization process, which makes the thermal stability of the halogen-free flame-retardant enhanced PBT composition poor, thereby generating a large amount of butadiene gas in a short time, and ultimately leading to material ignition failure and unsatisfactory hot-wire performance.

[0010] Generally, the tensile strength of a 30% glass fiber reinforced bromine-based flame-retardant PBT composition is 120-140 MPa, while the tensile strength of a 30% glass fiber reinforced halogen-free flame-retardant PBT composition is 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 bond of PBT will break to form more carboxyl-terminated molecular chains. These carboxyl-terminated molecular chains will further attack the ester groups, and the acidic environment provides a large number of hydrogen ions. Since the ester bond is a weak part of the PBT molecular structure, it is easily attacked by electrophilic hydrogen ions, thereby catalyzing and accelerating the degradation process of PBT, resulting in lower tensile strength of the halogen-free flame-retardant enhanced PBT composition.

[0011] Injection molding burn white and many factors, including materials, injection molding process, mold design and molding equipment. In terms of material, if the thermal stability of the material matrix itself is poor, it is easy to decompose in the injection molding process, a large amount of gas is generated, which is compressed to produce high temperature in the injection molding process, resulting in product burn white. For halogen-free flame-retardant reinforced PBT composition, the acidic halogen-free flame retardant has a catalytic degradation effect on PBT.

[0012] In summary, PBT will produce carboxyl-terminated molecular chains in the process of pyrolysis / hydrolysis, and the acidic environment provided by the carboxyl-terminated molecular chains and halogen-free flame retardant will further accelerate the degradation process. This leads to problems in the short-term performance (glow wire, tensile strength) and injection molding performance (burn white) of halogen-free flame-retardant reinforced PBT composition. In view of this, the present application reduces the acidity of carboxyl-terminated molecular chains and halogen-free flame retardant by stabilizer to reduce the degradation of PBT and reduce the content of initial carboxyl-terminated molecular chains in the system; for those molecular chains that have been degraded, reactive modifier is used to quench the activity of carboxyl-terminated molecular chains in PBT composition or connect carboxyl-terminated molecular chains with each other to play the role of "bridge". In this way, the pyrolysis / hydrolysis process caused by acid catalysis in PBT composition can be slowed down, and the product has excellent glow wire performance, good tensile strength and excellent injection molding appearance.

[0013] The polybutylene terephthalate resin composition provided by the present application is a high-glow-wire halogen-free flame-retardant reinforced PBT composition. The weight of polybutylene terephthalate in the polybutylene terephthalate resin composition is 45-56 parts by weight, for example, it can be 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.

[0014] The halogen-free flame retardant is 10-16 parts by weight, for example, it can be 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.

[0015] The halogen-free synergist is 2-6 parts by weight, for example, can be 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.

[0016] The glass fiber is 25-35 parts by weight, for example, can be 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.

[0017] The stabilizer is 0.4-1.5 parts by weight, for example, 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.

[0018] The modifier is 0.3-2 parts by weight, for example, 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 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, 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.

[0019] The following is a preferred technical solution of the present application, but not as a restriction on the technical solutions provided by the present application, through the following preferred technical solution, the purpose and beneficial effects of the present application can be better achieved and realized.

[0020] As a preferred technical solution, the intrinsic viscosity of the polybutylene terephthalate is 0.7-1.3 dL / g at 25℃, 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.

[0021] In the present 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℃, the dissolution time is 0.5h, the test temperature is 25℃, and the inner diameter of the viscosity tube is 0.77mm.

[0022] Preferably, the halogen-free flame retardant includes aluminum diethyl phosphinate and / or aluminum hypophosphite.

[0023] Preferably, the halogen-free synergist includes melamine polyphosphate and / or melamine cyanurate.

[0024] Preferably, the diameter of the glass fiber is 7-17μm, for example, it can be 7.5μm, 8μm, 8.5μm, 9μm, 9.5μm, 10μm, 10.5μm, 11μm, 11.5μm, 12μm, 12.5μm, 13μm, 13.5μm, 14μm, 14.5μm, 15μm, 15.5μm, 16μm, 16.5μm, etc.

[0025] Preferably, the glass fiber has a chopped length of 1-5mm, for example, it can be 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.2mm, 3.5mm, 3.8mm, 4mm, 4.2mm, 4.5mm, 4.8mm, etc.

[0026] Preferably, the stabilizer includes a first stabilizer and / or calcium stearate; the first stabilizer includes any one of magnesium oxide, calcium oxide or metal hydroxide.

[0027] 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.

[0028] Preferably, the stabilizer includes a combination of the first stabilizer and the calcium stearate.

[0029] Preferably, the mass ratio of the first stabilizer to calcium stearate in the stabilizer is 1:(0.5-5), which 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 is further preferably 1:(2-3), which 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.

[0030] In the present application, the calcium stearate has good compatibility with the polybutylene terephthalate resin composition system, the first stabilizer can better reduce the acidity of the carboxyl end group and the halogen-free flame retardant, and through the synergistic compounding of the calcium stearate and the first stabilizer, the degradation of the PBT can be reduced, so that the product has excellent glowing wire performance, good tensile strength, and excellent injection molding appearance.

[0031] Preferably, the modifier comprises a carbodiimide monomer and / or a polycarbodiimide, and the polycarbodiimide is further preferred.

[0032] Preferably, the NCN (-N=C=N-) content of the polycarbodiimide is ≥10%, which 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.

[0033] Preferably, the mass ratio of the stabilizer to the modifier is (0.3-3):1, which 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., and is further preferably (0.6-1.8):1, which 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.

[0034] Preferably, the components of the polybutylene terephthalate resin composition further comprise a lubricant.

[0035] Preferably, the lubricant comprises any one or a combination of at least two of an ester lubricant, a hydrocarbon lubricant, or a silicone lubricant.

[0036] Preferably, the ester lubricant comprises pentaerythritol stearate; illustratively, the pentaerythritol stearate can be purchased from, but not limited to, Shandong Ruiwei New Material PETS, Italy Fagron PETS-AP, Emery Olechemicals LOXIOL P 861 / 3.5, etc.

[0037] Preferably, the hydrocarbon lubricant comprises oxidized polyethylene wax.

[0038] Preferably, the silicone lubricant can be purchased, illustratively, can be purchased from, but not limited to, Zhejiang Ji Hua Jing Hua Stock Company Limited GT-300.

[0039] Preferably, the lubricant in the polybutylene terephthalate resin composition is 0.2-1 parts by weight, for example, can be 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.

[0040] Preferably, the components of the polybutylene terephthalate resin composition further comprise an antioxidant.

[0041] Preferably, the antioxidant comprises any one or a combination of at least two of a hindered phenolic antioxidant, a semi-hindered phenolic antioxidant, a phosphite antioxidant, or a sulfur fat antioxidant.

[0042] Preferably, the antioxidant in the polybutylene terephthalate resin composition is 0.1-0.5 parts by weight, for example, can be 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.

[0043] In a second aspect, the present application provides a preparation method of the polybutylene terephthalate resin composition according to the first aspect, the preparation method comprising:

[0044] The polybutylene terephthalate, the halogen-free flame retardant, the halogen-free synergist, the stabilizer, the modifier, and the glass fiber are melt blended and then extruded to obtain the polybutylene terephthalate resin composition.

[0045] Preferably, the melt blended material further comprises a lubricant and / or an antioxidant.

[0046] Preferably, the preparation method specifically comprises the following steps:

[0047] (1) the halogen-free flame retardant and the halogen-free synergist are mixed to obtain a first mixture; the polybutylene terephthalate, the stabilizer, the modifier, optionally the lubricant, and optionally the antioxidant are mixed to obtain a second mixture;

[0048] (2) the first mixture, the second mixture, and the glass fiber are melt blended and then extruded to obtain the polybutylene terephthalate resin composition.

[0049] Preferably, the rotation 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.

[0050] Preferably, the time of the first mixing 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.

[0051] Preferably, the rotation 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.

[0052] Preferably, the time of the second mixing 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.

[0053] Preferably, the melt blending is carried out in a screw extruder.

[0054] 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.

[0055] Preferably, the screw rotation 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.

[0056] Preferably, the extrusion further comprises a step of granulation.

[0057] In a third aspect, the present application provides a use of the polybutylene terephthalate resin composition according to the first aspect in electronic components, low-voltage electrical appliances and heat dissipation components.

[0058] Compared with the prior art, the present application has the following beneficial effects:

[0059] The polybutylene terephthalate resin composition provided by the present application has excellent glow wire performance and tensile strength, and also has good appearance, through the design of components and the synergistic compounding between components; wherein the GWIT of the polybutylene terephthalate resin composition is 775-850℃, the tensile strength is 100-115 MPa, the injection molding appearance whitening grade is 0-1 grade, and the flame retardant grade is V-0 grade. BRIEF DESCRIPTION OF DRAWINGS

[0060] Figure 1 is the evaluation standard diagram of the appearance whitening grade of the polybutylene terephthalate resin composition being 0 grade;

[0061] Figure 2 is the evaluation standard diagram of the appearance whitening grade of the polybutylene terephthalate resin composition being 1 grade;

[0062] Figure 3 is the evaluation standard diagram of the appearance whitening grade of the polybutylene terephthalate resin composition being 2 grade;

[0063] Figure 4 is the evaluation standard diagram of the appearance whitening grade of the polybutylene terephthalate resin composition being 3 grade. DETAILED DESCRIPTION

[0064] The technical solutions of the present application will be further described below in combination with the drawings and through specific embodiments. Those skilled in the art should understand that the embodiments are only to help understand the present application, and should not be regarded as specific limitations on the present application.

[0065] Some components in the following examples and comparative examples are as follows:

[0066] (1) Polybutylene terephthalate: purchased from Lantianhe, PBT TH6082, intrinsic viscosity of 0.82 dL / g (25℃);

[0067] (2) Aluminum diethylphosphinate: purchased from Clariant, Exolit OP 1230;

[0068] (3) Melamine polyphosphate: purchased from BUDIT, BUDIT 3141;

[0069] (4) Glass fiber: single filament diameter of 10 μm, chopped length of 4 mm, purchased from Taishan Glass Fiber Co., Ltd., HMG436S-10-4.0;

[0070] (5) Magnesium oxide: purchased from Kyowa Chemical Industry Co., Ltd., KYOWA MAG 150;

[0071] (6) Calcium stearate: purchased from Bolihe Chemical Industry (Zhongshan) Co., Ltd., BS-3818;

[0072] (7) Carbodiimide monomer: purchased from Rahn, Stabilizer 7000;

[0073] (8) Polycarbodiimide: purchased from Langyi Technology, Hymax213;

[0074] (9) Lubricant: ester lubricant, purchased from Fagron, PETS-AP;

[0075] (10) Antioxidant: hindered phenolic antioxidant, purchased from Sanfeng Chemical Industry, SONOX 1010;

[0076] (11) Magnesium hydroxide: purchased from Jiangsu Aiteke Flame Retardant Material Co., Ltd., Aitemag 55ZA2;

[0077] (12) Calcium oxide: purchased from Hangzhou Wenjian Calcium Industry Co., Ltd.

[0078] Example 1

[0079] A polybutylene terephthalate resin composition includes the following components in parts by weight:

[0080]

[0081]

[0082] A method for preparing the polybutylene terephthalate resin composition includes the following steps:

[0083] (1) mixing aluminum diethylphosphinate and melamine polyphosphate at 800 rpm for 3 min to obtain a first mixture; mixing polybutylene terephthalate, magnesium oxide, polycarbodiimide, lubricant PETS-AP and antioxidant SONOX 1010 at 700 rpm for 3 min to obtain a second mixture;

[0084] (2) adding the first mixture, the second mixture and glass fiber into a twin-screw extruder, the screw rotation speed of the twin-screw extruder is 300 rpm, the temperature of the first zone is 215°C, the temperature of the second zone is 250°C, the temperature of the third zone is 245°C, the temperature of the fourth zone is 245°C, the temperature of the fifth zone is 245°C, the temperature of the sixth zone is 250°C, the temperature of the seventh zone is 250°C, the temperature of the eighth zone is 230°C, the temperature of the ninth zone is 230°C, the temperature of the tenth zone is 250°C, after the above components are melt blended and extruded, granulated, the polybutylene terephthalate resin composition is obtained.

[0085] Examples 2-10, Comparative Examples 1-6

[0086] A polybutylene terephthalate resin composition, which is only different from Example 1 in that the types and / or amounts (parts by weight) of components are different, and the preparation method of the polybutylene terephthalate resin composition is the same as that of Example 1, as shown in Tables 1, 2 and 3.

[0087] Table 1

[0088] Components Example 1 Example 2 Example 3 Example 4 Example 5 Polybutylene terephthalate 54.6 50.2 45.3 50.2 50.2 Aluminum diethylphosphinate 10 13 16 13 13 Melamine polyphosphate 6 4 2 4 4 Glass fiber 25 30 35 30 30 Magnesium oxide 1.5 0.26 Magnesium hydroxide 0.5 Calcium stearate 0.9 0.64 0.9 Carbodiimide monomer 1 Polycarbodiimide 2 1 0.3 1 Lubricant PETS-AP 0.6 0.6 0.6 0.6 0.6 Antioxidant SONOX 1010 0.3 0.3 0.3 0.3 0.3

[0089] Table 2

[0090]

[0091] Table 3

[0092]

[0093]

[0094] Performance test

[0095] (1) Flame retardant performance: the polybutylene terephthalate resin composition is tested according to the UL 94 vertical burning standard;

[0096] (2) Glow wire test (GWIT): the polybutylene terephthalate resin composition is tested at different temperatures according to the standard IEC 60695-2-2013;

[0097] (3) Tensile strength: The polybutylene terephthalate resin composition was tested according to standard ISO 527; the testing instrument was a universal material testing machine (manufacturer: ZWICK, Germany, model: Z010), and the testing conditions were as follows: 10 mm / min;

[0098] (4) Whitening evaluation method: a Krauss Maffei machine (model CX 160-750) was used, the injection molding process was as follows: material temperature 275℃, medium-high injection speed, and 50 continuous injection molds, the whitening phenomenon of the last 5 molds was observed by visual observation, and the appearance of the polybutylene terephthalate resin composition was judged according to Figure 1 、 Figure 2 、 Figure 3 and Figure 4 If the appearance belongs to Figure 1 , the appearance whitening grade is 0, indicating no whitening; if the appearance belongs to Figure 2 , the appearance whitening grade is 1, indicating slight whitening; if the appearance belongs to Figure 3 , the appearance whitening grade is 2, indicating moderate whitening; and if the appearance belongs to Figure 4 , the appearance whitening grade is 3, indicating severe whitening.

[0099] Table 4

[0100]

[0101]

[0102] According to the performance test data in Table 4, by designing and compounding the stabilizer and the modifier, and synergizing with the halogen-free flame retardant and the halogen-free synergist, the polybutylene terephthalate resin composition has a GWIT≥775℃, and at the same time has excellent injection molding appearance and tensile strength, and is a high-performance polybutylene terephthalate resin composition with high tensile strength, high GWIT and good injection molding appearance.

[0103] It can be known from the comparison between Example 2 and Example 4 that the magnesium oxide and calcium stearate together as stabilizers can further improve the GWIT of the polybutylene terephthalate resin composition.

[0104] It can be known from the comparison between Example 2 and Example 5 that compared with the carbodiimide monomer, using the polycarbodiimide as the modifier can further improve the tensile strength and injection molding appearance of the polybutylene terephthalate resin composition.

[0105] The present application controls the mass ratio of the stabilizer and the modifier in a suitable range, and compounding with other components, so that the polybutylene terephthalate resin composition has excellent GWIT, tensile strength and injection molding appearance. The mass ratio of the stabilizer and the modifier in Example 6 is less than 0.6:1, the mass ratio of the stabilizer and the modifier in Example 7 is greater than 1.8:1, and the injection molding appearance of the polybutylene terephthalate resin composition is poor.

[0106] The present application controls the mass ratio of the first stabilizer and calcium stearate in a suitable range, and compounding with other components, so that the polybutylene terephthalate resin composition has excellent GWIT, tensile strength and injection molding appearance. The mass ratio of the first stabilizer and calcium stearate in Example 8 is less than 1:3, the mass ratio of the first stabilizer and calcium stearate in Example 9 is greater than 1:2, and the GWIT and tensile strength of the polybutylene terephthalate resin composition are poor relative to Example 4.

[0107] The present application screens specific types of stabilizers, so that the polybutylene terephthalate resin composition has high tensile strength, high GWIT and good injection molding appearance. However, Example 10 uses calcium oxide as a stabilizer, and because its reactivity is relatively weak, the GWIT of the polybutylene terephthalate resin composition is poor.

[0108] The present application designs the modifier and the stabilizer, and compounding with other components, so that the polybutylene terephthalate resin composition has excellent GWIT, tensile strength and injection molding appearance. Comparative Example 1 does not use a modifier and a stabilizer, and its GWIT is only 750℃, and the injection molding appearance is poor. Comparative Example 2, Comparative Example 3 and Comparative Example 6 use a stabilizer or a modifier alone, and relative to Comparative Example 1, the GWIT of the polybutylene terephthalate resin composition is not significantly improved, and the injection molding appearance is better. This is because the stabilizer can neutralize the acidity of the polybutylene terephthalate resin composition, thereby reducing the degradation of the polybutylene terephthalate resin composition due to acid catalysis, and reducing the generation of small molecule gases; the modifier can reconnect the small molecule chains cracked in the polybutylene terephthalate resin composition, and can to some extent reverse the degradation process of the polybutylene terephthalate, thereby reducing the generation of small molecule gases, and thus being more beneficial to improving the injection molding appearance. In Comparative Example 4, the amount of the modifier is too much, and the GWIT, tensile strength and injection molding appearance of the polybutylene terephthalate resin composition are poor. In Comparative Example 5, the amount of the stabilizer is too much, and the GWIT, tensile strength and injection molding appearance of the polybutylene terephthalate resin composition are poor.

[0109] The applicant states that the polybutylene terephthalate resin composition of the present application, the preparation method and the application thereof are illustrated by the above-mentioned embodiments, but the present application is not limited to the above-mentioned embodiments, i.e. it does not mean that the present application must rely on the above-mentioned embodiments to be implemented. It should be understood by those skilled in the art that any improvement of the present application, equivalent replacement of each raw material of the product of the present application, addition of auxiliary ingredients, selection of specific modes, etc. fall within the protection scope and the disclosed scope of the present application.

Claims

1. A polybutylene terephthalate resin composition, characterized by, The polybutylene terephthalate resin composition comprises the following components by weight parts: Polybutylene terephthalate 45-56 weight parts Halogen-free flame retardant 10.5-16 weight parts Halogen-free synergist 2-6 weight parts Glass fiber 25-35 weight parts Stabilizer 0.4-1.5 weight parts Modifier 0.3-2 weight parts The stabilizer comprises a combination of a first stabilizer and calcium stearate; the first stabilizer comprises any one of magnesium oxide, calcium oxide or metal hydroxide.

2. The polybutylene terephthalate resin composition according to claim 1, characterized by, The modifier comprises carbodiimide monomer and / or polycarbodiimide.

3. The polybutylene terephthalate resin composition according to claim 2, characterized by, The modifier comprises polycarbodiimide.

4. The polybutylene terephthalate resin composition according to claim 1, characterized by, The mass ratio of the stabilizer to the modifier is (0.3-3):

1.

5. The polybutylene terephthalate resin composition according to claim 4, characterized in that, The mass ratio of the stabilizer to the modifier is (0.6-1.8):

1.

6. The polybutylene terephthalate resin composition according to claim 1, characterized in that, The halogen-free flame retardant comprises aluminum diethyl phosphinate and / or aluminum hypophosphite.

7. The polybutylene terephthalate resin composition according to claim 1, characterized in that, The halogen-free synergist comprises melamine polyphosphate and / or melamine cyanurate.

8. The polybutylene terephthalate resin composition according to claim 1, characterized by, The metal hydroxide comprises any one of magnesium hydroxide, calcium hydroxide, sodium hydroxide, aluminum hydroxide, zinc hydroxide or iron hydroxide or a combination of at least two thereof.

9. The polybutylene terephthalate resin composition according to claim 1, characterized by, The mass ratio of the first stabilizer to calcium stearate in the stabilizer is 1:(0.5-5).

10. The polybutylene terephthalate resin composition according to claim 9, characterized in that, The mass ratio of the first stabilizer to calcium stearate in the stabilizer is 1:(2-3).

11. The polybutylene terephthalate resin composition according to claim 1, characterized in that, The components of the polybutylene terephthalate resin composition further comprise a lubricant.

12. The polybutylene terephthalate resin composition according to claim 11, characterized in that, The lubricant comprises any one of ester lubricant, hydrocarbon lubricant or silicone lubricant or a combination of at least two thereof.

13. The polybutylene terephthalate resin composition according to claim 11, wherein The lubricant in the polybutylene terephthalate resin composition is 0.2-1 weight parts.

14. The polybutylene terephthalate resin composition according to claim 1, characterized in that, The components of the polybutylene terephthalate resin composition further comprise an antioxidant.

15. The polybutylene terephthalate resin composition according to claim 14, characterized in that, The antioxidant comprises any one of hindered phenol antioxidant, semi-hindered phenol antioxidant, phosphite antioxidant or sulfur fat antioxidant or a combination of at least two thereof.

16. The polybutylene terephthalate resin composition according to claim 14, characterized in that, The antioxidant in the polybutylene terephthalate resin composition is 0.1-0.5 weight parts.

17. A method of producing the polybutylene terephthalate resin composition according to any one of claims 1 to 16, characterized by, The preparation method comprises: Polybutylene terephthalate, halogen-free flame retardant, halogen-free synergist, stabilizer, modifier and glass fiber are melt blended and then extruded to obtain the polybutylene terephthalate resin composition.

18. The method of claim 17, wherein, The melt blended material further comprises a lubricant and / or an antioxidant.

19. The method of claim 17, wherein, The preparation method specifically comprises 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, optionally the lubricant and optionally the antioxidant 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.

20. The method of claim 19, wherein, The rotation speed of the first mixing is 700-900 rpm.

21. The method of claim 19, wherein, The time of the first mixing is 2-4 min.

22. The preparation method according to claim 19, characterized in that, The rotation speed of the second mixing is 600-800 rpm.

23. The preparation method according to claim 19, characterized in that, The time of the second mixing is 2-4 min.

24. The method of claim 17, wherein, The melt blending is carried out in a screw extruder.

25. The method of claim 24, wherein, The temperature of each temperature zone of the screw extruder is independently 200-260℃.

26. The method of claim 24, wherein, The screw rotation speed of the screw extruder is 200-450 rpm.

27. The method of claim 17, wherein, The extrusion is followed by a step of pelletization.

28. Use of the polybutylene terephthalate resin composition according to any one of claims 1 to 16 in electronic components, low voltage electrical apparatus and heat dissipating parts.

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