A polybutylene terephthalate composition, its preparation method and application

Abstract

This invention discloses a polybutylene terephthalate (PET) composition, its preparation method, and its applications, belonging to the field of polymer materials technology. The PET composition, by weight, comprises the following components: 50-65 parts PET resin; 2-6 parts toughening agent; 12-25 parts brominated flame retardant; 2-8 parts inorganic aluminum hypophosphite; 2-5 parts phenyl phosphate; and 0-2 parts processing aid. The PET composition of this invention exhibits high flame retardancy, a high glow wire ignition temperature, and high toughness, while not significantly reducing rigidity.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and more specifically, to a polybutylene terephthalate composition, its preparation method, and its application. Background Technology

[0002] Polybutylene terephthalate (PBT) can be widely used in home appliances, electronic and electrical components, and medical products. These products all require materials with high glow wire ignition temperature and good toughness.

[0003] Currently, PBT solutions with high glow wire ignition temperatures (GWITs) typically employ a bromine-based system with a small amount of antimony white, along with a large amount of halogen-free flame retardant to enhance both flame retardancy and glow wire performance. However, the addition of halogen-free flame retardant significantly reduces the mechanical properties of the flame-retardant material. Therefore, a certain amount of toughening agent is added to improve the toughness of the PBT material. While the addition of toughening agent significantly improves the toughness, it negatively impacts the glow wire ignition temperature (GWIT). The IEC 60695 standard stipulates that for plastic parts used in electrical appliances that have long been unregulated, the GWIT must meet a requirement of ≥775℃. However, with the increasing functionality of electronic devices, specific components such as connectors, relay housings, and circuit breaker housings now require a GWIT of 850℃ or higher. Simultaneously, the plastic should not excessively sacrifice its toughness for the sake of higher GWIT, thus meeting the actual usage requirements.

[0004] Furthermore, existing technologies improve toughness by adding a large amount of toughening agent. However, the large amount of toughening agent added causes a significant decrease in the rigidity of flame-retardant materials, making it difficult to meet the functional testing requirements of plastic products used for connection or support in the electronics and electrical industry. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defects and shortcomings of existing polybutylene terephthalate compositions that cannot simultaneously achieve high glow wire ignition temperature, toughness and rigidity, and to provide a polybutylene terephthalate composition that has high flame retardancy, high glow wire ignition temperature and high toughness, while not significantly reducing rigidity.

[0006] Another object of the present invention is to provide a method for preparing a polybutylene terephthalate composition.

[0007] Another object of the present invention is to provide an application of a polybutylene terephthalate composition in the preparation of household appliances, electronic and electrical products, and medical products.

[0008] The above-mentioned objective of this invention is achieved through the following technical solution:

[0009] A polybutylene terephthalate composition, comprising the following components in parts by weight:

[0010] 50-65 parts of polybutylene terephthalate resin;

[0011] Toughening agent 2-6 parts;

[0012] 12-25 parts of brominated flame retardant;

[0013] 2-8 parts of inorganic aluminum hypophosphite;

[0014] 2-5 parts of phenyl phosphate;

[0015] Processing aids: 0-2 parts.

[0016] In the polybutylene terephthalate composition of the present invention, in a system containing a small amount of toughening agent and brominated flame retardant, the glow wire ignition temperature of the material is increased through the synergistic effect of inorganic aluminum hypophosphite and phenyl phosphate. In addition, the toughness of the material is simultaneously improved without causing significant negative impact on rigidity, thus realizing the preparation of flame-retardant PBT material with high toughness and high glow wire ignition temperature.

[0017] The addition of phenyl phosphate can effectively stabilize the P=O double bond of inorganic aluminum hypophosphite, improve the flame retardant effect and the glow wire ignition temperature.

[0018] Preferably, the mass percentage of polybutylene terephthalate resin in the composition is greater than 55%.

[0019] Preferably, the product comprises the following components by weight:

[0020] 50-65 parts of polybutylene terephthalate resin;

[0021] Toughening agent 2-6 parts;

[0022] 15-22 parts of brominated flame retardant;

[0023] 3-7 parts of inorganic aluminum hypophosphite;

[0024] 2.5 to 4 parts of phenyl phosphate;

[0025] Processing aids: 0-2 parts.

[0026] More preferably, by weight, it comprises the following components:

[0027] 50-65 parts of polybutylene terephthalate resin;

[0028] Toughening agent 2-6 parts;

[0029] 16-19 parts of brominated flame retardant;

[0030] Inorganic aluminum hypophosphite, 4.5–6.5 parts;

[0031] 2.5 to 3.5 parts of phenyl phosphate;

[0032] Processing aids: 0-2 parts.

[0033] Optionally, the toughening agent in the composition has a mass percentage of less than 8.5%.

[0034] Preferably, the toughening agent in the composition is 1.8%-6% by mass.

[0035] More preferably, the toughening agent in the composition is 2%-5.5% by mass.

[0036] Preferably, the composition contains less than 39% by mass of a brominated flame retardant.

[0037] More preferably, the composition contains less than 29% by mass of a brominated flame retardant.

[0038] The compositions of the present invention may not contain antimony-based flame retardants and / or antimony-based synergistic flame retardants, and preferably do not contain antimony white, antimony pentoxide and sodium antimonate, and may also have excellent flame retardant properties.

[0039] The inorganic aluminum hypophosphite has the molecular formula Al(H2PO2)3 and the CAS number 7784-22-7.

[0040] Preferably, the weight ratio of inorganic aluminum hypophosphite to phenyl phosphate is (0.7-4):1.

[0041] More preferably, the weight ratio of inorganic aluminum hypophosphite to phenyl phosphate is (2.5 to 3.5):1.

[0042] More preferably, the weight ratio of inorganic aluminum hypophosphite to phenyl phosphate is (2.6-2.8):1.

[0043] Optionally, the phenyl phosphate is at least one of triphenyl phosphate, resorcinol bis(diphenyl phosphate), bisphenol A bis(diphenyl phosphate), trimethylbenzene phosphate, cresol diphenyl phosphate, dicresol phenyl phosphate, hydroxyphenyl diphenyl phosphate, isopropylphenyl phenyl phosphate, or resorcinol bis[di(2,6-dimethylphenyl) phosphate].

[0044] Preferably, the phenyl phosphate is triphenyl phosphate.

[0045] Optionally, the toughening agent is at least one of ethylene-butyl acrylate-glycidyl methacrylate, ethylene-butyl acrylate copolymer, ethylene-methyl acrylate copolymer, or thermoplastic polyester elastomer.

[0046] Preferably, the toughening agent is ethylene-butyl acrylate-glycidyl methacrylate.

[0047] Optionally, the brominated flame retardant is at least one of brominated epoxy, brominated polystyrene, brominated polycarbonate, decabromodiphenyl ethane, pentabromobenzyl polyacrylate, or bromotriazine.

[0048] Preferably, the brominated flame retardant is brominated epoxy and / or decabromodiphenyl ethane.

[0049] More preferably, the brominated flame retardant is decabromodiphenyl ethane. This is because decabromodiphenyl ethane has a low molecular weight, thus having a smaller impact on the toughness of the material.

[0050] Optionally, the intrinsic viscosity of the polybutylene terephthalate resin is 0.73 to 1.3 dl / g, and the test standard is GB / T 14190-2017.

[0051] Optionally, the processing aid is an antioxidant or a lubricant. By weight, the aid may be 0-2 parts, and the aid is selected from one or more of antioxidants and lubricants.

[0052] Optionally, the antioxidant is one or more of hindered phenolic antioxidants, phosphite antioxidants, and organosulfur antioxidants.

[0053] Optionally, the lubricant is one or more of aliphatic carboxylic acid esters, erucamide, ethylene bis-stearamide, montan esters, polyethylene wax, and oxidized polyethylene wax.

[0054] The present invention also protects a method for preparing the polybutylene terephthalate composition according to any one of the above claims, comprising the following steps: mixing the components and adding them to an extruder, then melting, mixing, extruding and granulating to obtain the polybutylene terephthalate composition.

[0055] The melting and mixing temperature range is 180–260℃.

[0056] The twin-screw extruder has the following temperature zones: Zone 1: 30-200℃; Zone 2: 220-240℃; Zone 3: 230-250℃; Zone 4: 230-240℃; Zone 5: 180-240℃; Zone 6: 180-240℃; Zone 7: 180-240℃; Zone 8: 180-240℃; Zone 9: 180-240℃; Die head temperature: 210-250℃; and main extruder speed: 300-500 rpm.

[0057] This invention also protects the use of the polybutylene terephthalate composition described in any one of the above claims in the preparation of household appliances, electronic and electrical products, and medical products.

[0058] Home appliances can be electric motors.

[0059] Electronic and electrical products can include connectors, relays, etc.

[0060] Medical products can include medical devices, etc.

[0061] Compared with the prior art, the beneficial effects of the present invention are:

[0062] In the polybutylene terephthalate composition of the present invention, by introducing inorganic aluminum hypophosphite and phenyl phosphate into a flame retardant system mainly composed of bromine-based flame retardants, excellent thin-wall flame retardancy is achieved, which increases the glow wire ignition temperature of the material. In addition, the toughness of the material can be improved simultaneously by adding a small amount of toughening agent without causing significant negative impact on rigidity. This realizes the preparation of flame-retardant PBT materials with high toughness and high glow wire ignition temperature.

[0063] The polybutylene terephthalate composition of the present invention exhibits excellent toughness. With the addition of a small amount of toughening agent, the tensile strength can reach over 50.2 MPa, with a maximum of 58.8 MPa, and the notched impact strength can reach 5.0 KJ / mm². 2 The highest value can reach 6.6 KJ / mm. 2 It also has a high glow wire ignition temperature characteristic, with a GWIT of up to 800°C and up to 850°C, while the flame retardant rating can reach V0. Detailed Implementation

[0064] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise stated, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0065] The PBT resin, model PBT GX121, has a relative density of 1.31 and an intrinsic viscosity of 1.02 dl / g, and was purchased from the Yizheng Branch of China Petrochemical Corporation Asset Management Co., Ltd.

[0066] Toughening agent 1, ethylene-butyl acrylate-glycidyl methacrylate, brand name PTW, purchased from DuPont;

[0067] Toughening agent 2, ethylene-butyl acrylate copolymer, brand name ELVALOY AC 34035, purchased from DuPont;

[0068] Decabromodiphenyl ethane: Brand name SAYTEX 4010, purchased from Albemarle, USA;

[0069] Brominated epoxy: Grade F-2100, purchased from ICL in Israel;

[0070] Brominated polystyrene: brand name SAYTEX 621, purchased from Albemarle, USA;

[0071] Brominated polycarbonate: grade FG8500, purchased from Teijin, Japan;

[0072] Inorganic aluminum hypophosphite: grade M-116, purchased from Shanghai Meilaipo Chemical Materials Technology Co., Ltd.;

[0073] Aluminum diethylphosphinate: grade OP1230, purchased from Clariant, Germany;

[0074] Melamine cyanurate: Brand MCA-01, purchased from Sichuan Fine Chemicals Co., Ltd.

[0075] Tripropyl phosphate: Molecular formula: C9H 21 O4P, purchased from Aladdin Chemicals;

[0076] Phenylacetyl phosphate 1: Triphenyl phosphate, brand name TPP, purchased from Shanghai Zhuhui New Material Technology Co., Ltd.;

[0077] Phenylated phosphate 2: Resorcinol (diphenyl phosphate), brand name WSFR-RDP, purchased from Wansheng;

[0078] Antioxidant, pentaerythritol ester antioxidant, commercially available and the same type used in the parallel examples and comparative examples;

[0079] The lubricant, a polyethylene wax lubricant, is commercially available and the same type was used in the parallel examples and comparative examples.

[0080] Examples 1-11

[0081] A polybutylene terephthalate composition, comprising the following components in parts by weight:

[0082] Polybutylene terephthalate resin; toughening agent; brominated flame retardant; inorganic aluminum phosphonate; phenyl phosphate; processing aids; the processing aids are antioxidants and lubricants.

[0083] Table 1. Composition of the polybutylene terephthalate compositions in each embodiment (parts by weight)

[0084]

[0085]

[0086] The specific method for preparing the above-mentioned polybutylene terephthalate composition is as follows:

[0087] The dried polybutylene terephthalate resin and other components were uniformly mixed and then fed into a twin-screw extruder. The mixture was added in the first zone of the twin-screw extruder. The temperatures of the twin-screw extruder were as follows: zone 1: 180℃; zone 2: 220℃; zone 3: 230℃; zone 4: 240℃; zone 5: 240℃; zone 6: 230℃; zone 7: 230℃; zone 8: 220℃; zone 9: 220℃; die head temperature: 230℃; main extruder speed: 400 rpm. After extrusion, the mixture was cooled, pelletized, and dried to obtain the polybutylene terephthalate composition.

[0088] Comparative Examples 1-10

[0089] A polybutylene terephthalate composition, comprising the following components in parts by weight:

[0090] Polybutylene terephthalate resin; toughening agent; brominated flame retardant; inorganic aluminum hypophosphite; phenyl phosphate; processing aids; the processing aids are antioxidants and lubricants.

[0091] Table 2. Composition of polybutylene terephthalate compositions in each comparative example (parts by weight)

[0092]

[0093]

[0094] The preparation method of the above-mentioned polybutylene terephthalate composition is the same as that in the examples.

[0095] Result detection

[0096] The polybutylene terephthalate compositions of the above embodiments and comparative examples were all tested using the following performance test methods:

[0097] (1) Tensile strength: Tested according to standard ISO 527-2-2012, with a sample size of 150*10*4mm and a tensile speed of 10mm / min;

[0098] (2) Notched impact strength: Refer to standard ISO 180-11-2019, the specimen size is 80*10*3.2mm;

[0099] (3) Deflection: Refer to standard ISO 178-2010, the sample size is 80*10*4mm;

[0100] Notched impact strength and deflection are indicators for evaluating the toughness of materials. The greater the notched impact strength and deflection, the better the toughness of the material.

[0101] (4) Flame retardancy: The UL94-2013 flammability standard is used. The standard strip sample size is 125±5mm in length, 13.0±0.5mm in width, and 0.8±0.15mm in thickness.

[0102] The above mechanical spline molding conditions are: injection temperature 280℃, injection pressure 65%, injection speed 50%, and mold temperature 60℃.

[0103] (5) Glow Wire Ignition Temperature (GWIT): Tested according to IEC 60695-2-10:2013 standard. The test sample size is a 100*100*1.0mm square plate. The judgment criterion is: the highest temperature of the top of the glow wire that does not ignite in three consecutive tests of the specified thickness (30℃ higher for samples between 900℃ and 960℃). That is, as long as it does not ignite at the test temperature (for three consecutive samples), it passes the GWIT test. When calculating the actual GWIT, 25℃ needs to be added to this temperature, and 30℃ needs to be added for tests between 900℃ and 960℃. Note: Ignition means that the burning time exceeds 5 seconds.

[0104] The specific detection results for each embodiment are shown in Table 3 below:

[0105]

[0106]

[0107] The specific test results for each comparative example are shown in Table 4 below:

[0108]

[0109] As can be seen from the above data, the polybutylene terephthalate composition of the present invention has excellent toughness, with a tensile strength of over 50.2 MPa, reaching a maximum of 58.8 MPa, and a notched impact strength of up to 5.0 KJ / mm². 2 The highest value can reach 6.6 KJ / mm. 2 It also has the characteristic of resisting high glow wire ignition temperature. The GWIT of this composition can reach over 800°C, and can even reach 850°C. At the same time, the flame retardant rating can reach V0.

[0110] As can be seen from the examples and Comparative Example 1, in Comparative Example 1, the composition does not contain phenyl phosphate, which has poor flame retardancy and a low glow wire ignition temperature.

[0111] As can be seen from Examples and Comparative Example 2, the composition does not include inorganic aluminum hypophosphite, which has poor flame retardancy and a low glow wire ignition temperature.

[0112] As can be seen from Examples and Comparative Example 3, replacing inorganic aluminum hypophosphite with organic aluminum diethylphosphite, while achieving the required GWIT temperature and flame retardant properties, significantly reduces the toughness of the composition. This is likely because aluminum diethylphosphite catalyzes the degradation of the resin, thus leading to a decline in material performance, particularly a significant decrease in toughness.

[0113] As can be seen from Examples and Comparative Example 4, replacing phenyl phosphate with non-phenyl phosphate results in poor flame retardancy and an excessively low ignition temperature of the glow wire.

[0114] As can be seen from the examples and Comparative Example 5, in Comparative Example 5, the excessive addition of toughening agent significantly reduced the GWIT temperature, flame retardant properties, and rigidity of the material.

[0115] As can be seen from the examples and Comparative Example 6, in Comparative Example 6, the amount of phenyl phosphate was too small, which could not achieve good flame retardancy, especially since the GWIT temperature was too low.

[0116] As can be seen from the examples and Comparative Example 7, in Comparative Example 7, the amount of phenyl phosphate was too large. Although it had good flame retardancy and GWIT, the toughness of the material was too poor.

[0117] As can be seen from the examples and comparative examples 8 and 9, in comparative example 8, the amount of inorganic aluminum hypophosphite was too small, resulting in poor flame retardant performance and an inability to meet the requirements for glow wire ignition temperature. In comparative example 9, the amount of inorganic aluminum hypophosphite was too large; although the GWIT temperature and flame retardant performance met the requirements, the toughness of the material was significantly reduced.

[0118] As can be seen from Examples and Comparative Example 10, replacing phenyl phosphate with melamine cyanurate, a commonly used synergistic flame retardant in the art, while achieving the required GWIT temperature and flame retardant properties, results in a significant reduction in the toughness of the composition. This is likely because melamine cyanurate has a layered structure, which significantly affects the toughness of the material.

[0119] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A polybutylene terephthalate composition, characterized in that, By weight, it includes the following components: 50-65 parts of polybutylene terephthalate resin; Toughening agent 2-6 parts; 12-25 parts of brominated flame retardant; 2-8 parts of inorganic aluminum hypophosphite; 2-5 parts of phenyl phosphate; Processing aids: 0-2 parts.

2. The polybutylene terephthalate composition according to claim 1, characterized in that, By weight, it includes the following components: 50-65 parts of polybutylene terephthalate resin; Toughening agent 2-6 parts; 15-22 parts of brominated flame retardant; 3-7 parts of inorganic aluminum hypophosphite; 2.5 to 4 parts of phenyl phosphate; Processing aids: 0-2 parts.

3. The polybutylene terephthalate composition according to claim 1, characterized in that, In the composition, the toughening agent has a mass percentage of less than 8.5%.

4. The polybutylene terephthalate composition according to claim 1, characterized in that, The weight ratio of inorganic aluminum hypophosphite to phenyl phosphate is (0.7–4):

1.

5. The polybutylene terephthalate composition according to claim 1, characterized in that, The phenyl phosphate is at least one of triphenyl phosphate, resorcinol bis(diphenyl phosphate), bisphenol A bis(diphenyl phosphate), trimethylbenzene phosphate, cresol diphenyl phosphate, dicresol phenyl phosphate, hydroxyphenyl diphenyl phosphate, isopropylphenyl phenyl phosphate, or resorcinol bis[di(2,6-dimethylphenyl) phosphate].

6. The polybutylene terephthalate composition according to claim 1, characterized in that, The toughening agent is one or more of ethylene-butyl acrylate-glycidyl methacrylate, ethylene-butyl acrylate copolymer, ethylene-methyl acrylate copolymer, or thermoplastic polyester elastomer.

7. The polybutylene terephthalate composition according to claim 1, characterized in that, The brominated flame retardant is at least one of brominated epoxy, brominated polystyrene, brominated polycarbonate, decabromodiphenyl ethane, pentabromobenzyl polyacrylate, or bromotriazine.

8. The polybutylene terephthalate composition according to claim 1, characterized in that, Includes at least one of the following (a) to (b): (a) the relative viscosity of the polybutylene terephthalate resin is 0.73 to 1.3 dl / g, and the test standard is GB / T 14190-2017; (b) the processing aid is one or more combinations of antioxidants and lubricants.

9. A method for preparing the polybutylene terephthalate composition according to any one of claims 1 to 8, characterized in that, The process includes the following steps: mixing the components, adding them to an extruder, melting and mixing them, and then extruding and granulating them to obtain the polybutylene terephthalate composition.

10. The use of the polybutylene terephthalate composition according to any one of claims 1 to 8 in the preparation of household appliances, electronic and electrical products, and medical products.

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