Polybutylene terephthalate resin composition as well as preparation method and application thereof

Abstract

The invention provides a polybutylene terephthalate resin composition as well as a preparation method and application thereof. The polybutylene terephthalate resin composition is prepared from the following components in parts by weight: 45 to 56 parts by weight of polybutylene terephthalate, 10 to 16 parts by weight of halogen-free flame retardant, 2 to 6 parts by weight of halogen-free synergist, 25 to 35 parts by weight of glass fiber, 0.4 to 1.5 parts by weight of stabilizer and 0.3 to 2 parts by weight of modifier. According to the polybutylene terephthalate resin composition provided by the invention, through screening of all the components and synergistic compounding of the components, the polybutylene terephthalate resin composition has excellent glowing filament performance and tensile strength and good injection molding appearance, and can be applied to the field of electronics and electricity.

Description

Technical Field

[0001] The invention belongs to the technical field of engineering plastics, and in particular relates to a polybutylene terephthalate resin composition and a preparation method and application thereof. Background Art

[0002] In modern electronic and electrical equipment, more than 40% of the weight of the components are made of flammable plastic insulating materials. Due to overheating, leakage, sparks and aging, these devices may ignite materials and cause fires, causing great damage to people's lives and property safety. According to the IEC60695 standard, for unattended electrical appliances, if the rated current is greater than 0.2A, it must meet the following requirements: reaching UL94V-0 level, and no fire will occur within 30s when the 750℃ glow wire contacts the material or the burning time is less than 5s, that is, the glow wire ignition temperature (GWIT) is higher than 775℃. The purpose of the glow wire test is to simulate the thermal stress effect of heat sources such as overheated components or overload resistors on surrounding parts in a short period of time, so as to reflect the stability of electronic and electrical products during operation.

[0003] As one of the five commonly used engineering plastics, polybutylene terephthalate (PBT) has outstanding advantages such as high temperature resistance, oil resistance, chemical corrosion resistance, good electrical properties and short molding cycle. It is widely used in many fields such as electronics and electrical appliances, and home appliances. For this reason, the demand for high glow-wire performance of products is increasing. In addition, when solid waste containing brominated flame retardants is incinerated, toxic substances will be produced, causing lasting damage to the environment and human health, so PBT compositions are showing a trend of developing in the direction of halogen-free and environmentally friendly. However, due to the acidic environment of the halogen-free system and the catalytic degradation of PBT, the halogen-free flame retardant reinforced PBT composition has poor tensile strength and is prone to whitening during the injection molding process and other usage problems.

[0004] At present, the research on improving the glow-wire performance of halogen-free flame-retardant reinforced PBT compositions is relatively limited. The research focus is mainly on the compounding of bromine-based and halogen-free flame retardants to obtain high glow-wire performance. In addition, the existing halogen-free flame-retardant reinforced PBT compositions are more focused on the research of functional properties such as mechanics, flame retardancy, precipitation, and warpage. There is a blank in the research on making PBT compositions have good tensile strength, no injection whitening problem, and good glow-wire performance. Therefore, it is urgent to design a halogen-free flame-retardant reinforced PBT composition with excellent tensile strength, glow-wire performance, and injection appearance. Summary of the invention

[0005] In view of the deficiencies in the prior art, the object of the present invention is to provide a polybutylene terephthalate resin composition and a preparation method and application thereof. By screening the various components and synergistic compounding between the components, the polybutylene terephthalate resin composition has excellent glow-wire performance and tensile strength, as well as good injection molding appearance, and can be applied to the electronic and electrical fields.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a polybutylene terephthalate resin composition, wherein the polybutylene terephthalate resin composition comprises the following components in parts by weight:

[0008]

[0009] The reason why polybutylene terephthalate (PBT) fails due to glow-wire ignition is the generation of flammable gas. When PBT is thermally degraded, it will produce a large amount of flammable butadiene gas. Because its ignition concentration is low, it is very easy to fail due to ignition. For the thermal degradation process of PBT, there is a degradation pathway that is a molecular degradation process dominated by the β-H transfer mechanism. In this process, PBT will degrade to form terminal carboxyl and terminal vinyl molecular chains. The terminal carboxyl will further attack the ester group, thereby catalyzing the depolymerization reaction of the molecular chain; in addition, the acidic environment created by the halogen-free flame retardant will further accelerate this depolymerization process, which makes the thermal stability of the halogen-free flame retardant enhanced PBT composition itself poor, thereby generating a large amount of butadiene gas in a short time, which ultimately leads to material ignition failure and unsatisfactory glow-wire performance.

[0010] Usually, the tensile strength of 30% glass fiber reinforced bromine flame retardant PBT composition is 120-140MPa, while the tensile strength of 30% glass fiber reinforced halogen-free flame retardant PBT composition is 90-100MPa. The main reason behind this phenomenon is the acidic environment created by halogen-free flame retardants: under high temperature extrusion processing conditions, the ester bond of PBT will break, forming more terminal carboxyl molecular chains, which will further attack the ester group. At the same time, the acidic environment provides a large number of hydrogen ions. Since the ester bond is a weak part in the PBT molecular structure, it is very susceptible to electrophilic attack by hydrogen ions, which catalyzes and accelerates the degradation process of PBT, resulting in a low tensile strength of halogen-free flame retardant reinforced PBT resin.

[0011] Burning and whitening of injection molding is related to many factors, including materials, injection molding process, mold design and molding equipment. In terms of materials, if the thermal stability of the material matrix itself is poor, it is easy to decompose during the injection molding process, producing a large amount of gas, which will be compressed during the injection molding process to produce high temperatures, causing the product to burn and whiten. For halogen-free flame retardant reinforced PBT compositions, acidic halogen-free flame retardants have a catalytic degradation effect on PBT.

[0012] In summary, PBT will produce terminal carboxyl molecular chains during the pyrolysis / hydrolysis process, and the acidic environment provided by the terminal carboxyl and halogen-free flame retardant will further accelerate the degradation process. This leads to problems in the short-term performance (glowing wire, tensile strength) and injection molding performance (burning and whitening) of the halogen-free flame retardant reinforced PBT composition. In view of this, the present invention uses a stabilizer to reduce the acidity of the terminal carboxyl and halogen-free flame retardant to reduce the degradation of PBT and reduce the content of the initial terminal carboxyl molecular chain in the system; and for those molecular chains that have already degraded, a reactive modifier is used to quench the activity of the terminal carboxyl molecular chain in the PBT composition, or the terminal carboxyl molecular chains are connected to each other to play a "bridging" role. In this way, the pyrolysis / hydrolysis process caused by acid catalysis in the PBT composition can be slowed down, so that the product has excellent glowing wire performance, good tensile strength and excellent injection molding appearance.

[0013] The polybutylene terephthalate resin composition provided by the present invention is a high glow-wire halogen-free flame-retardant reinforced PBT composition, wherein the weight parts of polybutylene terephthalate in the polybutylene terephthalate resin composition are 45-56 weight parts, for example, 45 weight parts, 45.5 weight parts, 46 weight parts, 46.5 weight parts, 47 weight parts, 47.5 weight parts, 48 ​​weight parts, 48.5 weight parts, 49 weight parts, 49.5 weight parts, 50 weight parts, 50.5 weight parts, 51 weight parts, 51.5 weight parts, 52 weight parts, 52.5 weight parts, 53 weight parts, 53.5 weight parts, 54 weight parts, 54.5 weight parts, 55 weight parts, 55.5 weight parts, 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, 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 accounts for 25-35 parts by weight, for example, it 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, 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.

[0018] 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.

[0019] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0020] As a preferred technical solution, the intrinsic viscosity of the polybutylene terephthalate at 25°C is 0.7-1.3dL / g, for example, it can be 0.7dL / g, 0.75dL / g, 0.8dL / g, 0.85dL / g, 0.9dL / g, 0.95dL / g, 1dL / g, 1.05dL / g, 1.1dL / g, 1.15dL / g, 1.2dL / g, 1.25dL / g, etc.

[0021] In the present invention, 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.

[0022] Preferably, the halogen-free flame retardant comprises aluminum diethylphosphinate and / or aluminum hypophosphite.

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

[0024] 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.

[0025] 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.

[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 of magnesium hydroxide, calcium hydroxide, sodium hydroxide, aluminum hydroxide, zinc hydroxide or iron hydroxide, or a combination of at least two thereof.

[0028] Preferably, the stabilizer comprises 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), 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 further 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.

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

[0031] Preferably, the modifier comprises carbodiimide monomer and / or polycarbodiimide, more preferably polycarbodiimide.

[0032] 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.

[0033] Preferably, the mass ratio of the stabilizer to the modifier is (0.3-3):1, for example, 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 preferably (0.6-1.8):1, for example, it 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 include a lubricant.

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

[0036] Preferably, the ester lubricant includes pentaerythritol stearate; illustratively, the pentaerythritol stearate can be purchased from, but not limited to, Shandong Ruijie New Materials PETS, Italy Faji PETS-AP, Emory Oil Chemical Company LOXIOL P 861 / 3.5, etc.

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

[0038] Preferably, the silicone lubricant can be purchased, for example, GT-300 from Zhejiang Jiahua Jinghua Co., Ltd. but not limited to.

[0039] Preferably, the lubricant in the polybutylene terephthalate resin composition is 0.2-1 parts by weight, for example, it 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 include an antioxidant.

[0041] Preferably, the antioxidant comprises any one of a hindered phenol antioxidant, a semi-hindered phenol antioxidant, a phosphite antioxidant or a thiolipin antioxidant, or a combination of at least two thereof.

[0042] Preferably, the antioxidant in the polybutylene terephthalate resin composition is 0.1-0.5 parts by weight, for example, it 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 invention provides a method for preparing the polybutylene terephthalate resin composition as described in the first aspect, the preparation method comprising:

[0044] The polybutylene terephthalate resin composition is obtained by melt-blending polybutylene terephthalate, a halogen-free flame retardant, a halogen-free synergist, a stabilizer, a modifier and glass fiber and then extruding the mixture.

[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 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;

[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 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.

[0051] Preferably, the second mixing speed is 600-800 rpm, for example, 620 rpm, 640 rpm, 660 rpm, 680 rpm, 700 rpm, 720 rpm, 740 rpm, 760 rpm, 780 rpm, etc.

[0052] 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.

[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°C, for example, it can be 205°C, 210°C, 215°C, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C, 250°C, 255°C, etc.

[0055] 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.

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

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

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

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

[0060] Figure 1 This is a standard diagram for judging the whitening grade of the polybutylene terephthalate resin composition as grade 0;

[0061] Figure 2 This is a standard diagram for judging the whitening grade of the polybutylene terephthalate resin composition as Grade 1;

[0062] Figure 3 This is a standard diagram for judging the whitening grade of the polybutylene terephthalate resin composition as Grade 2;

[0063] Figure 4 This is a standard diagram for judging the whitening level of the polybutylene terephthalate resin composition as level 3. DETAILED DESCRIPTION

[0064] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0065] The sources of some components in the following examples and comparative examples are as follows:

[0066] (1) Polybutylene terephthalate: purchased from Lanshan Tunhe, PBT TH6082, intrinsic viscosity 0.82 dL / g (25°C);

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

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

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

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

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

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

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

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

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

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

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

[0078] Example 1

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

[0080]

[0081]

[0082] The preparation method of the polybutylene terephthalate resin composition comprises the following steps:

[0083] (1) mixing aluminum diethylphosphinate and melamine polyphosphate at a speed of 800 rpm for 3 min to obtain a first mixture; mixing polybutylene terephthalate, magnesium oxide, polycarbodiimide, lubricant PETS-AP and antioxidant SONOX1010 at a speed of 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, wherein the screw speed of the twin-screw extruder is 300 rpm, the temperature of zone 1 is 215°C, the temperature of zone 2 is 250°C, the temperature of zone 3 is 245°C, the temperature of zone 4 is 245°C, the temperature of zone 5 is 245°C, the temperature of zone 6 is 250°C, the temperature of zone 7 is 250°C, the temperature of zone 8 is 230°C, the temperature of zone 9 is 230°C, and the temperature of zone 10 is 250°C; the above components are melt-blended and then extruded, and granulated to obtain the polybutylene terephthalate resin composition.

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

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

[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 Fiberglass 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 SONOX1010 0.3 0.3 0.3 0.3 0.3

[0089] Table 2

[0090]

[0091] Table 3

[0092]

[0093]

[0094] Performance Testing

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

[0096] (2) Glow Wire Test (GWIT): The polybutylene terephthalate resin composition was tested at different temperatures according to 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 condition was 10 mm / min;

[0098] (4) Whitening evaluation method: Use a KraussMaffei machine (model CX 160-750), injection molding process: material temperature 275°C, medium-high speed injection, continuous injection of 50 molds, visually observe the whitening phenomenon of the last 5 molds, according to Figure 1 , Figure 2 , Figure 3 and Figure 4 The appearance of the polybutylene terephthalate resin composition was evaluated; if the appearance was Figure 1 , the whitening level is 0, indicating no whitening; if the appearance is Figure 2 , the whitening level is 1, indicating slight whitening; if the appearance is Figure 3 , the whitening level is 2, indicating medium whitening; if the appearance is Figure 4 , the whitening level is level 3, indicating severe whitening.

[0099] Table 4

[0100]

[0101]

[0102] According to the performance test data in Table 4, the present invention, through the design and compounding of stabilizers and modifiers, and the synergistic effect with halogen-free flame retardants and halogen-free synergists, makes the GWIT of the polybutylene terephthalate resin composition ≥ 775°C, and has excellent injection molding appearance and tensile strength. The present invention is a high-performance polybutylene terephthalate resin composition with high tensile strength, high GWIT and good injection molding appearance.

[0103] From the comparison between Example 2 and Example 4, it can be seen that the GWIT of the polybutylene terephthalate resin composition can be further improved by using magnesium oxide and calcium stearate together as stabilizers.

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

[0105] The present invention controls the mass ratio of the stabilizer to the modifier within a suitable range and compounding with other components to make the polybutylene terephthalate resin composition have excellent GWIT, tensile strength and injection molding appearance. In Example 6, the mass ratio of the stabilizer to the modifier is less than 0.6:1, and in Example 7, the mass ratio of the stabilizer to the modifier is greater than 1.8:1, and the injection molding appearance of the polybutylene terephthalate resin composition deteriorates.

[0106] The present invention controls the mass ratio of the first stabilizer to calcium stearate within a suitable range and compounding with other components to make the polybutylene terephthalate resin composition have excellent GWIT, tensile strength and injection molding appearance. 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 composition are worse than those of Example 4.

[0107] The present invention can make the polybutylene terephthalate resin composition have high tensile strength, high GWIT and good injection molding appearance by screening specific types of stabilizers. However, in Example 10, calcium oxide is used as a stabilizer. Due to its relatively weak reaction activity, the GWIT of the polybutylene terephthalate resin composition is poor.

[0108] The present invention makes the polybutylene terephthalate resin composition have excellent GWIT, tensile strength and injection molding appearance through the design of the modifier and the stabilizer, and compounding with other components. Comparative Example 1 does not use the modifier and the stabilizer, and its GWIT is only 750°C, and the injection molding appearance is poor. Comparative Examples 2, 3 and 6 use stabilizers or modifiers alone. Compared with Comparative Example 1, the GWIT of the polybutylene terephthalate resin composition is not significantly improved, and the injection molding appearance is improved. 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 under acid catalysis and reducing the generation of small molecule gases; the modifier can reconnect the cracked small molecule chains in the polybutylene terephthalate resin composition, which can reverse the degradation process of polybutylene terephthalate to a certain extent, reduce the generation of small molecule gases, and thus is more beneficial to improving the injection molding appearance. In Comparative Example 4, the amount of the modifier used was too much, and the GWIT, tensile strength and injection molding appearance of the polybutylene terephthalate resin composition were deteriorated. In Comparative Example 5, the amount of the stabilizer used was too much, and the GWIT, tensile strength and injection molding appearance of the polybutylene terephthalate resin composition were deteriorated.

[0109] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the polybutylene terephthalate resin composition of the present invention and its preparation method and application, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A polybutylene terephthalate resin composition, characterized in that The polybutylene terephthalate resin composition comprises the following components in parts by weight:

2. The polybutylene terephthalate resin composition according to claim 1, characterized in that The modifier includes carbodiimide monomer and / or polycarbodiimide, and polycarbodiimide is further preferred; Preferably, the mass ratio of the stabilizer to the modifier is (0.3-3):1, more preferably (0.6-1.8):

1.

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

4. The polybutylene terephthalate resin composition according to claim 1, characterized in that The stabilizer includes a first stabilizer and / or calcium stearate; the first stabilizer includes any one of magnesium oxide, calcium oxide or metal hydroxide; Preferably, the metal hydroxide includes any one of magnesium hydroxide, calcium hydroxide, sodium hydroxide, aluminum hydroxide, zinc hydroxide or iron hydroxide, or a combination of at least two thereof.

5. The polybutylene terephthalate resin composition according to claim 4, characterized in that: 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), more preferably 1:(2-3).

6. The polybutylene terephthalate resin composition according to claim 1, characterized in that: The components of the polybutylene terephthalate resin composition also include a lubricant; Preferably, the lubricant comprises any one of an ester lubricant, a hydrocarbon lubricant or a silicone lubricant, or a combination of at least two thereof; Preferably, the lubricant in the polybutylene terephthalate resin composition is 0.2-1 parts by weight.

7. The polybutylene terephthalate resin composition according to claim 1, characterized in that: The components of the polybutylene terephthalate resin composition also include an antioxidant; Preferably, the antioxidant comprises any one or a combination of at least two of a hindered phenol antioxidant, a semi-hindered phenol antioxidant, a phosphite antioxidant or a thiolipid antioxidant; Preferably, the antioxidant in the polybutylene terephthalate resin composition is 0.1-0.5 parts by weight.

8. A method for preparing the polybutylene terephthalate resin composition according to any one of claims 1 to 7, characterized in that: The preparation method comprises: The polybutylene terephthalate resin composition is obtained by melt-blending polybutylene terephthalate, a halogen-free flame retardant, a halogen-free synergist, a stabilizer, a modifier and glass fiber and then extruding the mixture.

9. The preparation method according to claim 8, characterized in that: The melt-blended material further comprises a lubricant and / or an antioxidant; Preferably, 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) melt-blending the first mixture, the second mixture and the glass fiber and then extruding them to obtain the polybutylene terephthalate resin composition; Preferably, the first mixing speed is 700-900 rpm; Preferably, the first mixing time is 2-4 min; Preferably, the second mixing speed is 600-800 rpm; Preferably, the second mixing time is 2-4 min; 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 further includes a granulation step.

10. Use of the polybutylene terephthalate resin composition according to any one of claims 1 to 7 in electronic components, low-voltage electrical appliances and heat dissipation parts.

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