PBT composition, preparation method therefor and use thereof

Abstract

Disclosed in the present invention are a PBT composition, a preparation method therefor, and a use thereof. The PBT composition comprises the following components in parts by weight: 45-55 parts of a PBT resin, 1.5-6 parts of an SAN resin, 1.5-4 parts of a toughening agent, 8-12 parts of a brominated flame retardant, 1.5-3 parts of a flame-retardant synergist, and 0.25-2 parts of a silicone lubricant. By means of the synergistic effect of the SAN resin and the silicone lubricant, the rate of carbon formation when an electrolyte drips onto the material surface can be greatly reduced, so that the prepared PBT composition has relatively high CTI and relatively good mechanical properties and flame retardant properties.

Description

A PBT composition, its preparation method and application Technical Field

[0001] This invention relates to the field of engineering plastics technology, and more specifically, to a PBT composition, its preparation method, and its application. Background Technology

[0002] Polybutylene terephthalate (PBT resin) is widely used in home appliances, automobiles, and electronics due to its excellent mechanical, electrical, aging, and solvent resistance properties. Flame-retardant reinforced PBT materials are often used in electronic components (such as relays, connectors, and power switches) and new energy components. These fields have high requirements for the electrical properties of materials, typically requiring a high relative tracking index (CTI).

[0003] For flame-retardant reinforced PBT materials, there are significant differences between halogenated and halogen-free systems. Halogen-free flame-retardant reinforced PBT products generally have a CTI (Critical Impact Test) above 500V, but their overall mechanical properties are generally inferior to those of halogenated systems. Halogenated flame-retardant reinforced products typically have a CTI of 200–225V, often failing to meet application requirements. Existing technology CN 106084686A provides a high-CTI flame-retardant reinforced PBT material, but its halogenated system only achieves a maximum CTI of 250V, and its impact strength is low. To improve impact strength, existing technologies often add ABS resin; however, ABS resin further degrades the CTI performance of the halogenated PBT system. Therefore, there is a need in this field to develop a halogenated flame-retardant reinforced PBT material with an even higher CTI. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects or problems of insufficient CTI and impact strength of halogenated flame-retardant reinforced PBT materials in the prior art, and to provide a PBT composition.

[0005] Another object of the present invention is to provide a method for preparing the PBT composition.

[0006] Another object of the present invention is to provide the application of the PBT composition.

[0007] To achieve the above objectives, the present invention employs the following technical solution:

[0008] A PBT composition comprising the following components in parts by weight:

[0009] In this invention, SAN resin is combined with silicone lubricant to improve the CTI value and mechanical properties of brominated flame retardant PBT. The synergistic effect of SAN resin and silicone lubricant significantly reduces the carbonization rate of electrolyte droplets on the material surface, thereby improving the CTI value.

[0010] Furthermore, preparing SAN resin, toughening agent, lubricant, brominated flame retardant and flame retardant synergist into flame retardant masterbatch can further improve CTI value. The inventors speculate that this may be because after being prepared into masterbatch, it helps to inhibit the formation of conductive pathways in the char layer by brominated flame retardant, thus weakening the charring ability and thereby improving CTI value.

[0011] It should be noted that the silicone lubricant may be silicone or silicone masterbatch, wherein the silicone content of the silicone masterbatch is 40-65 wt%, and the carrier may be linear low-density polyethylene and / or polypropylene.

[0012] Further, the PBT resin comprises 48-52 parts; SAN resin comprises 2.5-5 parts; toughening agent comprises 2-3.5 parts; and silicone lubricant comprises 0.5-1.5 parts.

[0013] Furthermore, the melt flow rate of the SAN resin at 220°C and a 10kg load is 10–60 g / 10 min, specifically 10 g / 10 min, 12 g / 10 min, 15 g / 10 min, 18 g / 10 min, 20 g / 10 min, 22 g / 10 min, 25 g / 10 min, 28 g / 10 min, 30 g / 10 min, 32 g / 10 min, 35 g / 10 min, 38 g / 10 min, 40 g / 10 min, 42 g / 10 min, 45 g / 10 min, 48 g / 10 min, 50 g / 10 min, 52 g / 10 min, 55 g / 10 min, 58 g / 0 min, or 60 g / 10 min, etc.

[0014] Furthermore, the melt flow rate of the silicone lubricant at 230°C and 2.16 kg load is ≥5 g / 10 min, preferably ≥8 g / 10 min; more preferably ≥10 g / 10 min.

[0015] Specifically, the melt flow rate of the silicone lubricant at 230°C and a load of 2.16 kg is 5–20 g / 10 min.

[0016] Furthermore, the test standard for the melt flow rate is ISO 1133-2011.

[0017] Furthermore, the toughening agent is one or more of ethylene-acrylate, ethylene-acrylate-glycidyl ester, ethylene-octene copolymer, ethylene-octene copolymer-glycidyl ester, or ethylene-vinyl acetate copolymer.

[0018] Further, the brominated flame retardant is one or more of brominated epoxy resin, brominated polystyrene, decabromodiphenyl ethane, pentabromobenzyl polyacrylate, brominated imine, brominated polycarbonate, or brominated triazine; preferably, the brominated flame retardant is one or more of brominated epoxy resin, brominated polystyrene, pentabromobenzyl polyacrylate, or brominated polycarbonate.

[0019] Furthermore, the flame retardant synergist is an antimony-containing flame retardant, such as antimony white or sodium antimonate.

[0020] Furthermore, the PBT composition further includes 0.1 to 5 parts of additives.

[0021] Furthermore, the additives include one or more of antioxidants, anti-hydrolysis agents, nucleating agents, or anti-dripping agents.

[0022] Specifically, in this invention, commonly used antioxidants can be selected according to existing technology, such as, but not limited to, one or more of phosphite antioxidants, thioether antioxidants, hindered phenolic antioxidants, or diphenylamine antioxidants.

[0023] In specific embodiments, the phosphite antioxidant is one or more of tris(2,4-di-tert-butylphenyl) phosphite (Irganox 168), bis(2,6-di-tert-butyl-4-tolyl) pentaerythritol phosphite (PEP-36), or 627A; the thioether antioxidant is one or more of distearate thiodipropionate, dilaurate thiodipropionate, or pentaerythritol-based dodecathiopropyl ester; the hindered phenolic antioxidant is N,N'-hexamethylene bis(3,5-di-tert-butyl-4-hydroxyphenylpropionamide) (Irganox 1098), pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (Irganox 1098). The diphenylamine antioxidant is one or more of 1,6-hexanediol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (Irganox 259), β-(4-hydroxy-3,5-di-tert-butylphenyl)propionate n-octadecyl ester (Irganox 1076), or 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)acrylic acid]-1,1-dimethyl}-2,4,8,10-tetraoxaspirocycloundecane (ADK AO-80); the diphenylamine antioxidant is one of butyl / octyl diphenylamine or dioctyl diphenylamine.

[0024] Specifically, the anti-dripping agent is polytetrafluoroethylene or polyvinylidene fluoride.

[0025] Specifically, the anti-hydrolysis agent is carbodiimide or polycarbodiimide.

[0026] Furthermore, the content of PBT resin in the PBT composition is not less than 40 wt%.

[0027] More preferably, the PBT composition contains essentially no ABS resin, specifically, the ABS resin content is less than 5wt%, 4.5wt%, 4wt%, 3.5wt%, 3wt%, 2.5wt%, 2wt%, 1.5wt%, 1wt%, 0.9wt%, 0.8wt%, 0.7wt%, 0.6wt%, 0.5wt%, 0.4wt%, 0.3wt%, 0.2wt%, or 0.1wt%.

[0028] Furthermore, the ABS resin content in the PBT composition is less than 2 wt%.

[0029] Furthermore, the intrinsic viscosity of the PBT resin is 0.8–1.1 dL / g.

[0030] Specifically, the intrinsic viscosity was tested according to the ISO 1628-5-2015 standard method.

[0031] Furthermore, the PBT composition further includes 25 to 35 parts of glass fiber.

[0032] Specifically, the glass fiber is alkali-free chopped E glass fiber with a diameter of 7μm to 15μm and a length of 3mm to 5mm.

[0033] This invention also protects a method for preparing the above-mentioned PBT composition, comprising the following steps:

[0034] After the components are mixed evenly, the PBT composition is obtained by melt blending and extrusion granulation.

[0035] Furthermore, the mixing speed is 200-400 rpm.

[0036] Furthermore, the mixing time is 2 to 4 minutes.

[0037] Furthermore, the extrusion granulation is carried out in a twin-screw extruder.

[0038] Furthermore, the temperature of the twin-screw extruder is 200-230℃ in zone 1, 240-260℃ in zone 2, 235-255℃ in zone 3, 235-255℃ in zone 4, 235-255℃ in zone 5, 240-260℃ in zone 6, 240-260℃ in zone 8, 240-260℃ in zone 9, and 240-260℃ in zone 10. The screw speed of the twin-screw extruder is 200-450 rpm.

[0039] Furthermore, the preparation method involves preparing SAN resin, toughening agent, brominated flame retardant, flame retardant synergist, silicone lubricant and additives into flame retardant masterbatch, which is then mixed uniformly with other components.

[0040] It should be noted that the flame retardant masterbatch can be prepared using conventional methods.

[0041] In a specific embodiment, the preparation method of the flame retardant masterbatch includes the following steps:

[0042] S1. Mix SAN resin, toughening agent, lubricant and additives evenly to obtain premix A; mix a portion of brominated flame retardant and flame retardant synergist evenly to obtain premix B;

[0043] S2. The premix A and premix B from step S1 are fed into the twin-screw extruder through the main feed port, and the remaining bromine-based flame retardant is fed in through the side feed port. The flame retardant masterbatch is obtained by melt blending and extrusion granulation.

[0044] Specifically, in step S2, the temperature of the extrusion granulation zone 1 is 190-210℃, the temperature of the second zone is 190-210℃, the temperature of the third zone is 200-220℃, the temperature of the fourth zone is 200-220℃, the temperature of the fifth zone is 200-220℃, the temperature of the sixth zone is 200-220℃, the temperature of the seventh zone is 200-220℃, the temperature of the eighth zone is 200-220℃, the temperature of the ninth zone is 200-220℃, and the temperature of the tenth zone is 200-220℃. The screw speed of the twin-screw extruder is 200-450 rpm.

[0045] This invention also protects the use of the above-mentioned PBT composition in the preparation of materials for household appliance components, new energy batteries, relays, or meters.

[0046] Compared with the prior art, the beneficial effects of the present invention are:

[0047] This invention provides a PBT material, which mainly improves the CTI by synergistically reducing the carbonization rate of electrolyte droplets on the material surface through SAN resin and silicone lubricant; and the silicone lubricant can be uniformly distributed on the material surface to form a dense hydrophobic layer, which can significantly reduce the carbonization rate of electrolyte droplets on the material surface when energized, thereby improving the CTI. The resulting PBT composition has a higher CTI value and better mechanical properties. Detailed Implementation

[0048] 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.

[0049] Raw materials used in the various embodiments and comparative examples of this invention:

[0050] SAN resin:

[0051] SAN resin 1: SAN NF2200, with a melt flow rate of 35 g / 10 min at 220°C and a load of 10 kg, was purchased from Taiwan Chemical Fiber Co., Ltd.

[0052] SAN resin 2: KFA-130H, with a melt flow rate of 55 g / 10 min at 220℃ and 10 kg load, was purchased from Liaoning Kingfa Science & Technology Co., Ltd.

[0053] SAN resin 3: KFA-180, with a melt flow rate of 10 g / 10 min at 220℃ and 10 kg load, was purchased from Liaoning Kingfa Science & Technology Co., Ltd.

[0054] ABS resin: ABSD-120A, with a melt flow rate of 10g / 10min at 220℃ and 10kg load, purchased from Guoqiao Petrochemical Co., Ltd.

[0055] Toughening agent: ethylene-methyl acrylate copolymer, AC 1125, purchased from DuPont;

[0056] Lubricant:

[0057] Lubricant 1: Silicone lubricant, GT-300, with a melt flow rate of 20g / 10min at 230℃ and 2.16kg load, purchased from Zhejiang Jiahua Fine Chemicals Co., Ltd.

[0058] Lubricant 2: Silicone lubricant, GT-600, with a melt flow rate of 9 g / 10 min at 230℃ and 2.16 kg load, purchased from Zhejiang Jiahua Fine Chemicals Co., Ltd.

[0059] Lubricant 3: Silicone lubricant, GT-800, with a melt flow rate of 5 g / 10 min at 230℃ and 2.16 kg load, purchased from Zhejiang Jiahua Fine Chemicals Co., Ltd.

[0060] Lubricant 4: Stearate lubricant, PETS-AP, purchased from Italian brand FARK;

[0061] Brominated flame retardants:

[0062] Brominated flame retardant 1: Brominated epoxy resin, F-2100, purchased from ICL, Israel;

[0063] Brominated flame retardant 2: Brominated polystyrene, SAYTEX 621, purchased from Albemarle, USA;

[0064] Bromine-based flame retardant 3: Decabromodiphenyl ethane, SAYTEX 8010, purchased from Albemarle, USA;

[0065] Flame retardant synergist: Antimony White, SN-05, purchased from Foshan Chenti Trade Co., Ltd.;

[0066] PBT resin:

[0067] PBT resin 1: PBT 1200-211M, intrinsic viscosity of 0.83 dL / g, purchased from Changchun Chemical (Jiangsu) Co., Ltd.

[0068] PBT resin 2: PBT 1100-211M, intrinsic viscosity of 1.0 dL / g, purchased from Changchun Chemical (Jiangsu) Co., Ltd.

[0069] Fiberglass: HMG436S-10-4.0, purchased from Taishan Fiberglass Co., Ltd.;

[0070] Additives:

[0071] Antioxidant: Hindered phenolic antioxidant, commercially available; Anti-dripping agent: Polytetrafluoroethylene, commercially available;

[0072] The same raw materials were used in the parallel experiments of each embodiment and comparative example.

[0073] According to the formulations in Tables 1-2, flame retardant masterbatches were prepared using the following preparation method:

[0074] S1. Mix SAN resin, toughening agent, silicone lubricant and additives at 700-900 rpm for 3 minutes to obtain premix A; mix a portion of brominated flame retardant and flame retardant synergist at 600-800 rpm for 3 minutes to obtain premix B.

[0075] S2. Premix A and premix B from step S1 are fed into a twin-screw extruder through the main feed port, and the remaining bromine-based flame retardant is fed in through the side feed port. After melt blending and extrusion granulation, flame retardant masterbatch is obtained. The temperature of the extrusion granulation zone 1 is 200℃, zone 2 is 200℃, zone 3 is 210℃, zone 4 is 210℃, zone 5 is 210℃, zone 6 is 210℃, zone 7 is 210℃, zone 8 is 210℃, zone 9 is 210℃, and zone 10 is 210℃. The screw speed of the twin-screw extruder is 300 rpm.

[0076] Table 1. Dosage of each component in each flame retardant masterbatch (unit: parts by weight)

[0077] Table 2. Dosage of each component in each flame retardant masterbatch (unit: parts by weight)

[0078] Examples 1-11 and Comparative Examples 1-4

[0079] PBT compositions were prepared according to the formulations in Tables 3-5, Examples 1-10 and Comparative Examples 1-3, by the following preparation method:

[0080] PBT resin, glass fiber, and flame-retardant masterbatch are mixed at 200–400 rpm for 2–4 minutes until homogeneous. The mixture is then melt-blended and extruded using a twin-screw extruder to obtain the PBT composition. The temperatures of the twin-screw extruder are as follows: Zone 1: 200–230℃; Zone 2: 240–260℃; Zone 3: 235–255℃; Zone 4: 235–255℃; Zone 5: 235–255℃; Zone 6: 240–260℃; Zone 7: 240–260℃; Zone 8: 240–260℃; Zone 9: 240–260℃; Zone 10: 240–260℃; and the screw speed of the twin-screw extruder is 200–450 rpm.

[0081] The preparation method of the PBT composition described in Example 11 is as follows:

[0082] The components are mixed at 200–400 rpm for 2–4 minutes until homogeneous, and then melt-blended and extruded using a twin-screw extruder to obtain the PBT composition. The temperatures of the twin-screw extruder are as follows: Zone 1: 200–230℃; Zone 2: 240–260℃; Zone 3: 235–255℃; Zone 4: 235–255℃; Zone 5: 235–255℃; Zone 6: 240–260℃; Zone 7: 240–260℃; Zone 8: 240–260℃; Zone 9: 240–260℃; Zone 10: 240–260℃; and the screw speed of the twin-screw extruder is 200–450 rpm.

[0083] The preparation method of the PBT composition described in Comparative Example 4 is as follows:

[0084] PBT resin, ABS resin, glass fiber, and flame retardant masterbatch are mixed at a speed of 200-400 rpm for 2-4 minutes until homogeneous. The mixture is then melt-blended and extruded using a twin-screw extruder to obtain a PBT composition. The temperatures of the twin-screw extruder are as follows: Zone 1: 200-230℃; Zone 2: 240-260℃; Zone 3: 235-255℃; Zone 4: 235-255℃; Zone 5: 235-255℃; Zone 6: 240-260℃; Zone 7: 240-260℃; Zone 8: 240-260℃; Zone 9: 240-260℃; Zone 10: 240-260℃; and the screw speed of the twin-screw extruder is 200-450 rpm.

[0085] Table 3. Amounts of each component in the PBT compositions of Examples 1-6 (unit: parts by weight)

[0086] Table 4. Amounts of each component in the PBT compositions of Examples 7-11 (unit: parts by weight)

[0087] Table 5. Amounts of each component in the PBT compositions of Comparative Examples 1–4 (unit: parts by weight)

[0088] Performance testing

[0089] 1. Testing Method

[0090] The PBT compositions prepared in the above examples and comparative examples were subjected to performance tests:

[0091] (1) Notched impact strength of cantilever beam: The PBT compositions prepared in the above examples and comparative examples were tested according to the standard ISO 180-2019.

[0092] (2) Flame retardant performance test: The PBT compositions prepared in the above examples and comparative examples were tested according to the UL94-2013 vertical burning standard, and the sample thickness was 1.5 mm.

[0093] (3) CTI performance test: The PBT compositions prepared in the above examples and comparative examples were prepared according to IEC 60112 standard, and ammonium chloride and distilled water were used to prepare solution A with a conductivity of 395±5Ω·m. The maximum voltage value that did not ignite or the current did not exceed 0.5A after 50 drops of solution A were tested using a CTI test instrument. A 100*100*3.0mm square plate was used for the test.

[0094] 2. Test Results

[0095] The performance test results of the PBT composition prepared by the above method are shown in Table 6.

[0096] Table 6 Performance test results of each embodiment and comparative example

[0097] As can be seen from Table 6, the PBT composition prepared in the embodiments of the present invention has a high CTI, and also exhibits good flame retardant and mechanical properties, specifically: a notched impact strength of not less than 8 kJ / m. 2 All of them can achieve a flame retardant rating of 1.5mm V-0, and a CTI value of over 275V.

[0098] As can be seen from Comparative Example 1, if other resins are used instead of SAN resin in the masterbatch, the CTI of the obtained PBT composition is only 225V, which is significantly worse than that of the example.

[0099] As can be seen from Comparative Example 2, if too much SAN resin is used in the masterbatch, the resulting PBT composition, although having a high CTI, will have reduced toughness and flame retardant properties.

[0100] As can be seen from Comparative Example 3, if other types of lubricants are used instead of silicone lubricants to prepare the masterbatch, the CTI of the PBT composition prepared by applying it to PBT resin is not significantly improved.

[0101] As can be seen from Comparative Example 4, although the impact strength is improved to a certain extent when ABS resin is introduced into the PBT composition, the CTI value decreases significantly.

[0102] 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 PBT composition, characterized in that, Includes the following components, calculated in parts by weight:

2. The PBT composition according to claim 1, characterized in that, The SAN resin has a melt flow rate of 10-60 g / 10 min at 220°C and a load of 10 kg.

3. The PBT composition according to claim 1, characterized in that, The silicone lubricant has a melt flow rate of ≥5g / 10min at 230℃ and 2.16kg load.

4. The PBT composition according to claim 1, characterized in that, The ABS resin content in the PBT composition is less than 5 wt%, preferably less than 2 wt%.

5. The PBT composition according to claim 1, characterized in that, The brominated flame retardant is one or more of brominated epoxy resin, brominated polystyrene, decabromodiphenyl ethane, pentabromobenzyl polyacrylate, brominated imine, brominated polycarbonate, or brominated triazine; preferably, the brominated flame retardant is one or more of brominated epoxy resin, brominated polystyrene, pentabromobenzyl polyacrylate, or brominated polycarbonate.

6. The PBT composition according to claim 1, characterized in that, The silicone lubricant is silicone or silicone masterbatch.

7. The PBT composition according to claim 1, characterized in that, It also includes 0.1 to 5 parts of additives and 25 to 35 parts of glass fiber.

8. A method for preparing the PBT composition according to any one of claims 1 to 7, characterized in that, Includes the following steps: After the components are mixed evenly, the PBT composition is obtained by melt blending and extrusion granulation.

9. The preparation method according to claim 8, characterized in that, A flame-retardant masterbatch is prepared by combining SAN resin, toughening agent, brominated flame retardant, flame retardant synergist, lubricant and additives, and then mixed evenly with other components.

10. The use of the PBT composition according to claims 1 to 7 in the preparation of materials for household appliance components, new energy batteries, relays, or meters.

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