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

Abstract

The invention relates to 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 55 parts by weight of polybutylene terephthalate, 8 to 15 parts by weight of halogen-free flame retardant, 1 to 6 parts by weight of halogen-free synergist, 25 to 35 parts by weight of glass fiber, 1 to 3 parts by weight of physical covering agent, 0.1 to 0.6 part by weight of main antioxidant and 0.1 to 0.6 part by weight of auxiliary antioxidant, the polybutylene terephthalate resin composition also contains free organic silicon; the total content of silicon elements in free organic silicon in the polybutylene terephthalate resin composition is 1 to 500 ppm. The polybutylene terephthalate resin composition provided by the invention has excellent injection molding processing color stability, flame retardant property and mechanical property through the design of each component and dosage.

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 insulation 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. When the waste of brominated flame retardant products is incinerated, toxic substances will be produced, causing lasting damage to the environment and human health, so the entire industry is showing a trend of developing in the direction of halogen-free and environmentally friendly.

[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, electrical insulation performance and short molding cycle. It is widely used in many fields such as electronic appliances, automobiles, textiles, and precision instrument components. At present, with the rapid development of energy storage and new energy industries, the requirements for high temperature resistance and aging resistance of circuit connections and protective devices are getting higher and higher; and with the improvement of people's living standards, the requirements for materials are no longer limited to use, but also require sensory experience. However, polymer materials will have different degrees of discoloration during high-temperature processing, and the discoloration problem of thin-walled products that require harsh injection molding processes is more serious. The current halogen-free flame-retardant reinforced PBT material has a color difference of more than 2.0 between the color plates of the first mold and the second mold during the injection molding process, and there is a problem of poor color stability. In this context, higher requirements are put forward for the color stability of PBT materials during injection molding, which is essentially to control the appearance of the product when it leaves the factory and the quality stability of the product during use.

[0004] At present, there is little research on the color stability of halogen-free flame-retardant reinforced PBT materials under injection molding, and the focus is mainly on halogen-containing flame-retardant PBT materials. For example, CN114517004A discloses a good-appearance glass fiber reinforced flame-retardant PBT composition and its preparation method and application. Through the reasonable combination of flame retardant, titanium dioxide, antimony white and glass fiber, the brominated flame-retardant reinforced PBT composition has good fluidity and small color difference during processing, and at the same time has good mechanical properties and flame retardant properties.

[0005] In order to comply with the trend of PBT compositions developing towards halogen-free and environmentally friendly, it is necessary to design a halogen-free flame-retardant reinforced PBT composition with small color difference during processing and excellent tensile strength and flame retardant properties. Summary of the invention

[0006] 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 color stability during injection molding, and at the same time has good mechanical properties and flame retardant properties, and can be used in many fields such as motors, new energy, and kitchen appliances.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] 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:

[0009]

[0010] The polybutylene terephthalate resin composition further contains free silicone; the total silicon content of the free silicone in the polybutylene terephthalate resin composition is 1-500 ppm.

[0011] In the present invention, the free silicone can be derived from silicone compounds and / or polymer silicone. When the free silicone is derived from silicone compounds, all of the silicone compounds serve as free silicone in the polybutylene terephthalate resin composition; when the free silicone is derived from polymer silicone, the small molecular silicon-containing substances (molecular weight ≤ 800 g / mol) contained in the polymer silicone serve as free silicone.

[0012] When the free silicone is derived from an organosilicon compound, the total silicon content of the free silicone in the polybutylene terephthalate resin composition is lower than its theoretical value due to the loss of the organosilicon compound during the processing.

[0013] In the present invention, the detection method of free silicone is: using acetone solvent to extract the polybutylene terephthalate resin composition at 120° C. and 3 MPa for 2 hours to separate the free silicone, and using an electric blast drying oven to heat and evaporate the organic solvent, adding 5 mL of nitric acid + 2 mL of hydrogen peroxide solution, and using a microwave digester to perform wet digestion, the extracted free silicone is converted into inorganic silicon and fixed to 50 mL with ultrapure water, and then using the ICP-OES method to test the content of silicon element in the free silicone, each group of samples is tested twice, and the average value is taken as the final result.

[0014] The polybutylene terephthalate resin composition provided by the present invention is a halogen-free flame retardant reinforced PBT composition, in which the polybutylene terephthalate in the polybutylene terephthalate resin composition is 45-55 parts by weight, for example, 46 parts by weight, 47 parts by weight, 48 parts by weight, 49 parts by weight, 50 parts by weight, 51 parts by weight, 52 parts by weight, 53 parts by weight, 54 parts by weight, etc.

[0015] The halogen-free flame retardant is 8-15 parts by weight, for example, it can be 8.5 parts by weight, 9 parts by weight, 9.5 parts by weight, 10 parts by weight, 10.5 parts by weight, 11 parts by weight, 11.5 parts by weight, 12 parts by weight, 12.5 parts by weight, 13 parts by weight, 13.5 parts by weight, 14 parts by weight, 14.5 parts by weight, etc.

[0016] The halogen-free synergist is 1-6 parts by weight, for example, 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight, 3 parts by weight, 3.5 parts by weight, 4 parts by weight, 4.5 parts by weight, 5 parts by weight, 5.5 parts by weight, etc.

[0017] The glass fiber accounts for 25-35 parts by weight, for example, 26 parts by weight, 27 parts by weight, 28 parts by weight, 29 parts by weight, 30 parts by weight, 31 parts by weight, 32 parts by weight, 33 parts by weight, 34 parts by weight, etc.

[0018] The physical covering agent is 1-3 parts by weight, for example, 1.2 parts by weight, 1.4 parts by weight, 1.6 parts by weight, 1.8 parts by weight, 2 parts by weight, 2.2 parts by weight, 2.4 parts by weight, 2.6 parts by weight, 2.8 parts by weight, etc.

[0019] The total silicon content of the free silicone is 1-500ppm, for example, it can be 1ppm, 20ppm, 50ppm, 80ppm, 100ppm, 120ppm, 150ppm, 180ppm, 200ppm, 220ppm, 250ppm, 280ppm, 300ppm, 320ppm, 350ppm, 380ppm, 400ppm, 420ppm, 450ppm, 480ppm, 500ppm and the like.

[0020] The primary antioxidant is 0.1-0.6 parts by weight, for example, 0.15 parts by weight, 0.2 parts by weight, 0.25 parts by weight, 0.3 parts by weight, 0.35 parts by weight, 0.4 parts by weight, 0.45 parts by weight, 0.5 parts by weight, 0.55 parts by weight, etc.

[0021] The auxiliary antioxidant is 0.1-0.6 parts by weight, for example, 0.15 parts by weight, 0.2 parts by weight, 0.25 parts by weight, 0.3 parts by weight, 0.35 parts by weight, 0.4 parts by weight, 0.45 parts by weight, 0.5 parts by weight, 0.55 parts by weight, etc.

[0022] In the present invention, the main antioxidant and the auxiliary antioxidant are of different types and have different effects. The combination of the two has a synergistic effect. In addition, increasing the addition amount of the main antioxidant and the auxiliary antioxidant can improve the color stability of the polybutylene terephthalate resin composition.

[0023] 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.

[0024] As a preferred technical solution, the total silicon content of free silicone in the polybutylene terephthalate resin composition is 50-250 ppm, for example, it can be 60 ppm, 80 ppm, 100 ppm, 120 ppm, 140 ppm, 160 ppm, 180 ppm, 200 ppm, 220 ppm, 240 ppm, etc.

[0025] Preferably, the intrinsic viscosity of the polybutylene terephthalate at 25° C. is 0.7-1.3 dL / g, for example, 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 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.

[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 physical covering agent includes any one of titanium dioxide, zinc sulfide, calcium carbonate or antimony trioxide or a combination of at least two thereof, further preferably any one of titanium dioxide, zinc sulfide or antimony trioxide or a combination of at least two thereof, and more preferably titanium dioxide.

[0032] In the present invention, titanium dioxide, zinc sulfide, calcium carbonate and antimony trioxide are white fillers, which play a role in physically covering the color of the polybutylene terephthalate resin composition. Among them, the effect of titanium dioxide is better, and the more it is added, the smaller the color difference. However, adding too much will lead to a decrease in the mechanical properties of the polybutylene terephthalate resin composition.

[0033] Preferably, the free silicone is derived from silicone, and the silicone includes any one or a combination of at least two of silane, siloxane, functional masterbatch, polysiloxane, silicone rubber or organosilicate derivatives.

[0034] Preferably, the silane includes any one of tetraphenylsilane, trimethylphenylsilane or methyltriphenylsilane, or a combination of at least two thereof.

[0035] Preferably, the siloxane includes any one of dodecamethylcyclohexasiloxane, decamethylcyclopentasiloxane or octamethylcyclotetrasiloxane, or a combination of at least two thereof.

[0036] Preferably, the functional masterbatch is a silicone masterbatch.

[0037] Preferably, the polysiloxane comprises dimethicone and / or polymethylphenylsiloxane.

[0038] Preferably, the silicone rubber includes methyl vinyl silicone rubber and / or room temperature vulcanized silicone rubber.

[0039] Preferably, the organic silicate derivative comprises organic montmorillonite and / or organic vermiculite.

[0040] Preferably, the primary antioxidant comprises any one of a hindered amine antioxidant, a hindered phenol antioxidant or a semi-hindered phenol antioxidant, or a combination of at least two thereof, preferably a semi-hindered phenol antioxidant.

[0041] Preferably, the hindered amine antioxidant comprises poly[[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imino]-1,6-hexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino]] and / or bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate.

[0042] In the present invention, the hindered amine antioxidant is exemplarily purchased from, but not limited to, BASF CHIMASSORB944FDL and Tianjin Li'anlong New Materials Co., Ltd. RIASORB UV-770DF.

[0043] Preferably, the hindered phenol antioxidant includes any one of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] pentaerythritol ester, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl ester, (3,5-di-tert-butyl-4-hydroxyphenyl)propionate oxalyl(diimino-2,1-ethylene ester) or N,N'-(hexane-1,6-diyl)bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide] or a combination of at least two thereof, and further preferably any one of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] pentaerythritol ester, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl ester or N,N'-(hexane-1,6-diyl)bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide] or a combination of at least two thereof.

[0044] In the present invention, the hindered phenol antioxidant is exemplarily purchased from, but not limited to, SONOX 1010, SONOX 1076, SONOX 1098, and SONOX 1027 from Sanfeng Chemical Co., Ltd., Linyi City, Shandong Province.

[0045] Preferably, the semi-hindered phenol antioxidant includes tri(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanuric acid and / or triethylene glycol ether-di(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate, and triethylene glycol ether-di(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate is further preferred.

[0046] In the present invention, the semi-hindered phenol antioxidant is exemplarily purchased from, but not limited to, Antioxidant 1790 from Tianjin Lianlong New Materials Co., Ltd. and IRGANOX 245 from BASF.

[0047] Preferably, the auxiliary antioxidant includes any one of an aryl phosphite antioxidant, an alkyl phosphite antioxidant or a thioester antioxidant, or a combination of at least two thereof, and an aryl phosphite antioxidant is further preferred.

[0048] Preferably, the aromatic phosphite antioxidant includes tris(2,4-di-tert-butylphenyl) phosphite.

[0049] In the present invention, the aryl phosphite antioxidant is exemplarily purchased from, but not limited to, SONOX168 from Sanfeng Chemical.

[0050] Preferably, the alkyl phosphite antioxidant includes any one or a combination of at least two of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphate, bis(2,4-dicumylphenyl)pentaerythritol-diphosphite or 3,9-bis(octadecyl)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane.

[0051] In the present invention, the alkyl phosphite antioxidant is exemplarily purchased from, but not limited to, ADEKA PEP-36, Dover S-9228, and Foshan Yuansheng Chemical Co., Ltd. AP-618.

[0052] Preferably, the thioester antioxidant includes pentaerythritol tetrakis(3-lauryl thiopropionate) and / or distearyl thiodipropionate, and pentaerythritol tetrakis(3-lauryl thiopropionate) is further preferred.

[0053] In the present invention, the thioester antioxidant is exemplarily purchased from, but not limited to, RIANOX 412S and DSTDP from Tianjin Li'anlong New Materials Co., Ltd.

[0054] Preferably, the mass ratio of the primary antioxidant to the auxiliary antioxidant is 1:(0.3-3) (for example, 1:0.33, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8, 1:2, 1:2.2, 1:2.4, 1:2.6, 1:2.8, etc.), and more preferably 1:(1.5-2.5).

[0055] Preferably, the total mass of the primary antioxidant and the auxiliary antioxidant in the polybutylene terephthalate resin composition is 0.3-0.9 parts by weight (for example, 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, etc.), and further preferably 0.5-0.8 parts by weight (for example, 0.52 parts by weight, 0.55 parts by weight, 0.58 parts by weight, 0.6 parts by weight, 0.62 parts by weight, 0.65 parts by weight, 0.68 parts by weight, 0.7 parts by weight, 0.72 parts by weight, 0.75 parts by weight, 0.78 parts by weight, etc.).

[0056] Preferably, the components of the polybutylene terephthalate resin composition further include a toughening agent.

[0057] Preferably, the amount of toughening agent in the polybutylene terephthalate resin composition is ≤5 parts by weight, for example, it can be 0.2 parts by weight, 0.5 parts by weight, 0.8 parts by weight, 1 part by weight, 1.2 parts by weight, 1.5 parts by weight, 1.8 parts by weight, 2 parts by weight, 2.5 parts by weight, 2.8 parts by weight, 3 parts by weight, 3.2 parts by weight, 3.5 parts by weight, 3.8 parts by weight, 4 parts by weight, 4.2 parts by weight, 4.5 parts by weight, 4.8 parts by weight, etc.

[0058] Preferably, the toughening agent includes any one of ethylene-acrylate copolymer, ethylene-acrylate-glycidyl methacrylate copolymer or ethylene-octene-glycidyl methacrylate copolymer, or a combination of at least two thereof.

[0059] Preferably, the components of the polybutylene terephthalate resin composition further include a lubricant.

[0060] Preferably, the amount of lubricant in the polybutylene terephthalate resin composition is ≤1 part by weight, for example, it can be 0.1 part by weight, 0.15 part by weight, 0.2 part by weight, 0.25 part by weight, 0.3 part by weight, 0.35 part by weight, 0.4 part by weight, 0.45 part by weight, 0.5 part by weight, 0.55 part by weight, 0.6 part by weight, 0.65 part by weight, 0.7 part by weight, 0.8 part by weight, 0.9 part by weight, etc.

[0061] Preferably, the lubricant includes any one of pentaerythritol stearate lubricants, oxidized polyethylene wax or montan ester lubricants, or a combination of at least two thereof.

[0062] 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:

[0063] The polybutylene terephthalate resin composition is obtained by melt-blending polybutylene terephthalate, a halogen-free flame retardant, a halogen-free synergist, glass fiber, a physical covering agent, silicone, a primary antioxidant and an auxiliary antioxidant and then extruding the mixture.

[0064] Preferably, the melt-blended material further comprises a lubricant and / or a toughening agent.

[0065] Preferably, the preparation method specifically comprises the following steps:

[0066] (1) the halogen-free flame retardant and the halogen-free synergist are first mixed to obtain a first mixture; the polybutylene terephthalate, the physical covering agent, the silicone, the primary antioxidant, the auxiliary antioxidant, optionally the lubricant and optionally the toughening agent are second mixed to obtain a second mixture;

[0067] (2) The first mixture, the second mixture and the glass fiber are melt-blended and then extruded to obtain the polybutylene terephthalate resin composition.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] Preferably, the melt blending is carried out in a screw extruder.

[0073] 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.

[0074] 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.

[0075] Preferably, the extrusion further includes a granulation step.

[0076] In a third aspect, the present invention provides a use of the polybutylene terephthalate resin composition as described in the first aspect in low-voltage electrical appliances, household appliances, new energy batteries or heat dissipation components.

[0077] Preferably, the polybutylene terephthalate resin composition is used in an electric motor stator, an energy storage connector, a junction box or a battery cover.

[0078] Compared with the prior art, the present invention has the following beneficial effects:

[0079] The polybutylene terephthalate resin composition provided by the present invention has excellent color stability, flame retardant properties and mechanical properties during injection molding through the synergistic effect of a physical covering agent, free silicone, a primary antioxidant and an auxiliary antioxidant, and through the coordination with other components of the polybutylene terephthalate resin composition. The polybutylene terephthalate resin composition provided by the present invention has a flame retardant grade of V-0, a tensile strength of ≥90MPa, and a color stability of injection molding △E≤1.40. DETAILED DESCRIPTION

[0080] For the convenience of understanding the present invention, the present invention lists the following embodiments. 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.

[0081] The sources of some components in the embodiments and comparative examples are as follows:

[0082] (1) PBT resin: purchased from Lanshan Tunhe, PBT TH6082, intrinsic viscosity 0.82 dL / g (25°C);

[0083] (2) Aluminum diethylphosphinate: purchased from Clariant, Germany, Exolit OP 1230;

[0084] (3) Melamine polyphosphate: purchased from Budenheim, Germany, BUDIT 3141;

[0085] (4) Glass fiber: single filament diameter 10 μm, length 4 mm, purchased from Taishan Glass Fiber Co., Ltd., HMG436S-10-4.0;

[0086] (5) Ethylene-methyl acrylate copolymer: purchased from DuPont, ELVALOYAC RESIN 1125;

[0087] (6) Lubricant (pentaerythritol stearate): purchased from Italy, PETS-AP;

[0088] (7) Physical covering agent:

[0089] Titanium dioxide, purchased from DuPont, R104;

[0090] Zinc sulfide, purchased from Guangdong Xinda New Materials Technology Co., Ltd., MX622;

[0091] Antimony white, purchased from Changde Chenzhou Antimony Products Co., Ltd., S-05N;

[0092] (8) Silicone:

[0093] Silicone masterbatch, purchased from Dow Corning, MB50-002;

[0094] Tetraphenylsilane, purchased from Beijing Solebow Technology Co., Ltd., YS156779;

[0095] Dodecamethylcyclohexasiloxane, purchased from Hubei Jusheng Technology Co., Ltd., JS2114;

[0096] Dimethyl silicone oil, purchased from Guangzhou Huisi Composite Materials Co., Ltd., O-SO4;

[0097] Methyl vinyl silicone rubber, purchased from Dongguan Shuangao Plastic Co., Ltd., 110-1;

[0098] Organic montmorillonite, purchased from Beijing Yiwei Special Chemical Technology Development Co., Ltd., I.3PS;

[0099] (9) Primary antioxidant:

[0100] Semi-hindered phenol antioxidant, purchased from BASF, IRGANOX 245;

[0101] Hindered phenol antioxidant, purchased from Sanfeng Chemical, SONOX 1010;

[0102] Hindered phenol antioxidant, purchased from Sanfeng Chemical, SONOX 1027;

[0103] (10) Auxiliary antioxidants:

[0104] Aryl phosphite antioxidant, purchased from Sanfeng Chemical, SONOX 168;

[0105] Alkyl phosphite antioxidant, purchased from ADEKA, PEP-36;

[0106] Thioester antioxidant, purchased from Lianlong, DSTDP.

[0107] In the following embodiments and comparative examples, the detection method of free silicone is as follows: using acetone solvent to extract the polybutylene terephthalate resin composition at 120°C and 3MPa for 2h to separate the free silicone, and using an electric blast drying oven to heat and evaporate the organic solvent, adding 5mL nitric acid + 2mL hydrogen peroxide solution, and using a microwave digester to perform wet digestion, the extracted free silicone is converted into inorganic silicon and fixed to 50mL with ultrapure water, and then using the ICP-OES method to accurately test the content of silicon element in the free silicone brought by the silicone, and each group of samples is tested twice, and the average value is taken as the final result.

[0108] Example 1

[0109] A polybutylene terephthalate resin composition, comprising the following components in parts by weight:

[0110]

[0111]

[0112] The preparation method of the polybutylene terephthalate resin composition comprises the following steps:

[0113] (1) mixing aluminum diethylphosphinate and melamine polyphosphate at a rotation speed of 800 rpm for 3 min to obtain a first mixture; mixing polybutylene terephthalate, ethylene-methyl acrylate copolymer, pentaerythritol stearate, titanium dioxide, tetraphenylsilane, primary antioxidant IRGANOX 245 and auxiliary antioxidant SONOX 168 at a rotation speed of 700 rpm for 3 min to obtain a second mixture;

[0114] (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.

[0115] Examples 2-18, Comparative Examples 1-6

[0116] A polybutylene terephthalate resin composition, which differs from Example 1 only in the types and / or amounts (parts by weight) of components, as shown in Tables 1, 2 and 3. The silicon content of free silicone in the polybutylene terephthalate resin composition is shown in the table below; the preparation method of the polybutylene terephthalate resin composition is the same as that of Example 1.

[0117] Table 1

[0118]

[0119]

[0120] Table 2

[0121]

[0122]

[0123] Table 3

[0124]

[0125] Performance Testing

[0126] (1) Flame retardant properties: The polybutylene terephthalate resin composition was tested according to the UL94 vertical burning standard;

[0127] (2) 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;

[0128] (3) Color stability of injection molding: The polybutylene terephthalate resin composition was placed in an injection molding machine at an injection molding temperature of 270°C. 200 color plates were continuously injection molded. The color difference between the first and 200th color plates was measured using a colorimeter (X-rite Color-Eye 7000A, X-Rite (Shanghai) Color Technology Co., Ltd.) and recorded as △E.

[0129] The polybutylene terephthalate resin compositions provided in Examples 1-18 and Comparative Examples 1-6 were tested according to the above method. The test results are shown in Table 4:

[0130] Table 4

[0131]

[0132]

[0133] It can be seen from the data in Table 4 that the present invention, through the compounding of physical covering agent, free silicone, primary antioxidant and auxiliary antioxidant, and the cooperation with halogen-free flame retardant and halogen-free synergist, makes the polybutylene terephthalate resin composition have excellent color stability during injection molding, and also has excellent flame retardant properties and tensile strength.

[0134] As can be seen from Examples 1-6, using silicone to increase the content of free silicone in the polybutylene terephthalate resin composition is more conducive to improving the color stability of the injection molding of the polybutylene terephthalate resin composition. When the free silicone is derived from silicone compounds, the total silicon content of the free silicone in the polybutylene terephthalate resin composition is lower than its theoretical value due to the loss of the silicone compounds during the processing.

[0135] It can be seen from Example 1, Example 7 and Example 8 that titanium dioxide can better improve the color stability of the injection molding of the polybutylene terephthalate resin composition compared with other physical covering agents.

[0136] It can be seen from Examples 1, 9 and 10 that when the dosage ratio of the primary antioxidant to the auxiliary antioxidant is within an appropriate range, the color stability of the polybutylene terephthalate resin composition during injection molding can be improved. When the dosage ratio of the two is within a preferred range, the color stability of the polybutylene terephthalate resin composition during injection molding can be further improved.

[0137] It can be seen from Examples 1, 11 and 12 that the total amount of the primary antioxidant and the auxiliary antioxidant is controlled within a preferred range, which can maintain the color stability of the polybutylene terephthalate resin composition during injection molding at a high level; if the total amount of the two is too small (Example 11) or too large (Example 12), the color stability of the polybutylene terephthalate resin composition during injection molding will be deteriorated; in addition, if the total amount of the primary antioxidant and the auxiliary antioxidant is too large, the risk of precipitation will increase during the injection molding process.

[0138] It can be seen from Example 1 and Examples 13-16 that selecting appropriate primary antioxidants and auxiliary antioxidants is more conducive to improving the color stability of the injection molding process of the polybutylene terephthalate resin composition.

[0139] It can be seen from Example 1 and Examples 17-18 that by controlling the silicon content of the free silicone in the polybutylene terephthalate resin composition within a suitable range, the color stability of the polybutylene terephthalate resin composition during injection molding can be further improved.

[0140] From the comparison between Example 1 and Comparative Examples 1-5, it can be seen that the color stability of the injection molding of the polybutylene terephthalate resin composition can be improved through the combined effect of the physical covering agent, free silicone, primary antioxidant and auxiliary antioxidant, and none of the four is dispensable.

[0141] From the comparison between Example 1 and Comparative Example 6, it can be seen that if the amount of the physical covering agent is too much, the mechanical properties of the polybutylene terephthalate resin composition will be seriously deteriorated.

[0142] 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: The polybutylene terephthalate resin composition also contains free silicone; The total silicon content of free organic silicon in the polybutylene terephthalate resin composition is 1-500 ppm.

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

3. The polybutylene terephthalate resin composition according to claim 1, 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 physical covering agent includes any one or a combination of at least two of titanium dioxide, zinc sulfide, calcium carbonate or antimony trioxide, more preferably any one or a combination of at least two of titanium dioxide, zinc sulfide or antimony trioxide, and more preferably titanium dioxide; Preferably, the free silicone is derived from silicone, and the silicone includes any one or a combination of at least two of silane, siloxane, functional masterbatch, polysiloxane, silicone rubber or organosilicate derivatives; Preferably, the silane includes any one of tetraphenylsilane, trimethylphenylsilane or methyltriphenylsilane, or a combination of at least two thereof; Preferably, the siloxane includes any one of dodecamethylcyclohexasiloxane, decamethylcyclopentasiloxane or octamethylcyclotetrasiloxane, or a combination of at least two thereof; Preferably, the functional masterbatch is a silicone masterbatch; Preferably, the polysiloxane comprises dimethyl silicone oil and / or polymethylphenylsiloxane; Preferably, the silicone rubber comprises methyl vinyl silicone rubber and / or room temperature vulcanized silicone rubber; Preferably, the organic silicate derivative comprises organic montmorillonite and / or organic vermiculite.

5. The polybutylene terephthalate resin composition according to claim 1, characterized in that: The primary antioxidant comprises any one of a hindered amine antioxidant, a hindered phenol antioxidant or a semi-hindered phenol antioxidant or a combination of at least two thereof, preferably a semi-hindered phenol antioxidant; Preferably, the hindered amine antioxidant comprises poly[[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imino]-1,6-hexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino]] and / or bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate; Preferably, the hindered phenol antioxidant includes any one of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] pentaerythritol ester, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl ester, (3,5-di-tert-butyl-4-hydroxyphenyl)propionate oxalyl(diimino-2,1-ethylene ester) or N,N'-(hexane-1,6-diyl)bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide] or a combination of at least two thereof, and further preferably any one of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] pentaerythritol ester, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl ester or N,N'-(hexane-1,6-diyl)bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide] or a combination of at least two thereof; Preferably, the semi-hindered phenol antioxidant includes tri(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanuric acid and / or triethylene glycol ether-di(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate, and triethylene glycol ether-di(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate is further preferred.

6. The polybutylene terephthalate resin composition according to claim 1, characterized in that: The auxiliary antioxidant includes any one of an aryl phosphite antioxidant, an alkyl phosphite antioxidant or a thioester antioxidant, or a combination of at least two thereof, and an aryl phosphite antioxidant is further preferred; Preferably, the aromatic phosphite antioxidant comprises tris(2,4-di-tert-butylphenyl) phosphite; Preferably, the alkyl phosphite antioxidant includes any one or a combination of at least two of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphate, bis(2,4-dicumylphenyl)pentaerythritol-diphosphite or 3,9-bis(octadecyl)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane; Preferably, the thioester antioxidant includes pentaerythritol tetrakis (3-lauryl thiopropionate) and / or distearyl thiodipropionate, and pentaerythritol tetrakis (3-lauryl thiopropionate) is further preferred; Preferably, the mass ratio of the primary antioxidant to the auxiliary antioxidant is 1:(0.3-3), more preferably 1:(1.5-2.5); Preferably, the total weight of the primary antioxidant and the auxiliary antioxidant in the polybutylene terephthalate resin composition is 0.3-0.9 parts by weight, and more preferably 0.5-0.8 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 a toughening agent; Preferably, the toughening agent in the polybutylene terephthalate resin composition is ≤ 5 parts by weight; Preferably, the toughening agent comprises any one of ethylene-acrylate copolymer, ethylene-acrylate-glycidyl methacrylate copolymer or ethylene-octene-glycidyl methacrylate copolymer or a combination of at least two thereof; Preferably, the components of the polybutylene terephthalate resin composition further include a lubricant; Preferably, the lubricant in the polybutylene terephthalate resin composition is ≤ 1 part by weight; Preferably, the lubricant includes any one of pentaerythritol stearate lubricants, oxidized polyethylene wax or montan ester lubricants, or a combination of at least two thereof.

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, glass fiber, a physical covering agent, silicone, a primary antioxidant and an auxiliary antioxidant and then extruding the mixture.

9. The preparation method according to claim 8, characterized in that: The melt-blended material also includes a lubricant and / or a toughening agent; 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 physical covering agent, the silicone, the primary antioxidant, the auxiliary antioxidant, optionally the lubricant and optionally the toughening agent 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 low-voltage electrical appliances, household appliances, new energy batteries or heat dissipation components.

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