PBT (Polybutylene Terephthalate) composite material with low-temperature impact resistance and damp-heat aging resistance and preparation method of PBT composite material

Abstract

The invention belongs to the technical field of high polymer materials, and relates to a PBT (Polybutylene Terephthalate) composite material with low-temperature impact resistance and damp-heat aging resistance and a preparation method of the PBT composite material. The preparation method comprises the following steps: adding PBT, a styrene-acrylonitrile-organic silicon copolymer, silicone master batches, an organic silicon flexibilizer and other raw materials into a double-screw extruder through a main feeding port A, and carrying out melt extrusion granulation to obtain the PBT composite material with low-temperature impact resistance and damp-heat aging resistance. According to the invention, the low-temperature impact resistance and damp-heat aging resistance of the PBT composite material are remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials and relates to a PBT composite material resistant to low-temperature impact and moisture-heat aging and a preparation method thereof. Background Art

[0002] New energy vehicles offer advantages such as energy conservation, environmental friendliness, and low noise levels. With strong national support for the development of the new energy vehicle industry, the number of new energy vehicles on the road is rapidly increasing. As an essential component of the new energy vehicle industry, the charging gun sector holds enormous potential for development. Due to my country's vast territory, charging guns are often exposed to extremely harsh environments, placing extremely stringent demands on the materials used. The gun tip, in particular, must withstand both low-temperature and high-temperature, high-humidity environments.

[0003] Polybutylene terephthalate (PBT), a semi-crystalline engineering plastic, possesses excellent mechanical properties, electrical insulation, and chemical resistance, and holds great potential for application in charging gun tips. However, the presence of PBT's benzene ring structure can easily lead to stress concentration, resulting in poor low-temperature impact resistance. Furthermore, the presence of ester groups significantly limits PBT's resistance to wet-heat aging, significantly limiting its application in charging gun tips. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems existing in the prior art and provide a PBT composite material that is resistant to low-temperature impact and resistant to moist heat aging and a preparation method thereof.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A PBT composite material with low-temperature impact resistance and heat and humidity aging resistance contains, by weight, 100 parts of PBT, 8-20 parts of SAS (styrene-acrylonitrile-organic silicon copolymer), 1-2 parts of silicone masterbatch, 5-8 parts of silicone toughening agent, 15-20 parts of polypentabromobenzyl acrylate, 4-6 parts of phosphazene flame retardant, and 10-30 parts of glass fiber, wherein the carrier resin of the silicone masterbatch is PC.

[0007] In the styrene-acrylonitrile-silicone copolymer, the styrene component and the acrylonitrile component are polar, while the silicone component is non-polar. The polar styrene component and acrylonitrile component have good compatibility with polar PBT, while the non-polar silicone component has poor compatibility with polar PBT. This results in the styrene component and acrylonitrile component entering the interior of the composite material during the melt blending process, while the silicone component floats on the surface of the composite material. The silicone component can significantly improve the hydrophobicity of the composite material, thereby improving the composite material's resistance to moisture and heat aging.

[0008] In the prior art, styrene-acrylonitrile-silicone copolymers are introduced into composite materials mainly to improve the heat resistance (the material's tolerance to heat at a macroscopic level, specifically, it focuses on the temperature at which the material reaches a certain deformation under load conditions, i.e., the heat deformation temperature) and antibacterial properties of the composite materials. The present invention is the first to introduce styrene-acrylonitrile-silicone copolymers into composite materials based on the motivation of improving the composite material's resistance to wet heat aging (used to evaluate the degree to which the material retains its mechanical properties after a certain period of time under high temperature and high humidity environmental conditions).

[0009] During the melt blending process, the carrier resin PC of the silicone masterbatch and silicone will both migrate to the surface of the composite material. The hydrolysis reaction activity of PC is higher than that of PBT and it is easier to hydrolyze. PC acts as a sacrificial protective substance to protect PBT from the influence of high temperature moisture. At the same time, silicone can also significantly improve the hydrophobicity of the composite material, further improving the composite material's resistance to moisture and heat aging.

[0010] In the prior art, silicone masterbatch is introduced into composite materials mainly for dispersion and lubrication, such as aiding dispersion, facilitating demoulding, and increasing scratch resistance. The present invention is the first to introduce silicone masterbatch into composite materials based on the motivation of improving the moisture and heat aging resistance of composite materials.

[0011] The addition of organosilicon toughening agents can effectively improve the low-temperature impact resistance of the composite material, while further increasing the silicon content on the surface of the composite material, thereby further improving the moisture-heat aging resistance of the composite material.

[0012] Pentabromobenzyl acrylate has good compatibility with PBT. Compared with other halogen flame retardants, it achieves the same flame retardant effect with a small addition amount and has little effect on the mechanical properties of the material, thereby improving the material's impact resistance, especially low-temperature impact resistance.

[0013] Phosphazene flame retardant can be fully integrated with PBT, increasing the mobility of PBT molecular chains, thereby reducing the internal stress of PBT. The reduction of internal stress not only ensures excellent low-temperature impact resistance, but also has some beneficial effects on improving the resistance to wet and hot aging.

[0014] The glass fiber can be made of hydrolysis-resistant glass fiber to further improve the hydrolysis resistance of the composite material.

[0015] As the preferred technical solution:

[0016] The PBT composite material having low-temperature impact resistance and heat and humidity aging resistance as described above has an intrinsic viscosity of 0.8-1.3.

[0017] The melt flow rate of the PBT composite material resistant to low temperature impact and moisture and heat aging at 220°C and 10 kg load is 3-21 cm 3 / 10min.

[0018] In the above-mentioned PBT composite material that is resistant to low-temperature impact and resistant to heat and humidity aging, the organosilicon-based toughening agent is a silicone-acrylic acid type high weathering and impact-resistant modifier.

[0019] In the above-mentioned PBT composite material that is resistant to low-temperature impact and resistant to moist heat aging, the phosphazene flame retardant is hexaphenoxycyclotriphosphazene.

[0020] The PBT composite material resistant to low temperature impact and moisture-heat aging as described above has a CTI (Comparative Tracking Index) value of 300-350V and a notched impact strength of 8.5-10.6 kJ / m at 23°C. 2 , notched impact strength at -40℃ is 7.5-8.9kJ / m 2 , UL94 reaches V0 grade. After being placed under the conditions of relative humidity of 85% and temperature of 85℃ for 240h, the notched impact strength retention rate at 23℃ is more than 79%, and the notched impact strength retention rate at -40℃ is more than 76%. UL94 still reaches V0 grade.

[0021] The present invention also provides a method for preparing a PBT composite material that is resistant to low-temperature impact and moisture-heat aging as described in any of the above items, comprising adding glass fiber to a twin-screw extruder through a main feed port B, and adding other components to the twin-screw extruder through a main feed port A, and melt-extruding and granulating, wherein the speed of the twin-screw extruder is 450-600 rpm and the temperature is 220-230°C; in order to ensure that the composite material has an excellent appearance, the glass fiber is added through the main feed port, the retained length of the glass fiber is reduced, the exposure of the glass fiber is improved, the appearance texture is enhanced, and the composite material has a good appearance to meet the aesthetic requirements of the public.

[0022] Beneficial effects:

[0023] The present invention significantly improves the low-temperature impact resistance and moisture-heat aging resistance of the PBT composite material, broadens the application field of the PBT material, and also provides more reliable material support for the development of the new energy vehicle industry. DETAILED DESCRIPTION

[0024] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0025] The following are the test methods for the relevant performance indicators in each embodiment:

[0026] CTI value: Cut the sample to be tested into discs with a thickness of 3 mm and a diameter of 100 mm and test according to the IEC 60112 standard.

[0027] Notched impact strength and notched impact strength retention: According to ISO 179, the sample to be tested was dried in a forced air oven at 110°C for 4 hours, then injection molded into a standard specimen for testing. The notched impact strength retention was calculated as follows:

[0028] Notched impact strength retention rate = a c1 / a c0 ×100%;

[0029] Where a c0 It is the notched impact strength of the original specimen at a specific temperature (23°C or -40°C), in kJ / m 2 ;a c1 It is the notched impact strength of the original specimen at the same specific temperature after being subjected to heat and humidity aging treatment (placed at a relative humidity of 85% and a temperature of 85°C for 240 hours), in kJ / m 2 .

[0030] UL94: Tested in accordance with UL94 standard, with a sample thickness of 1.6 mm.

[0031] Example 1

[0032] A method for preparing a PBT composite material that is resistant to low-temperature impact and resistant to moist heat aging, comprising the following steps:

[0033] (1) Preparation of raw materials;

[0034] Glass fiber: The manufacturer is Chongqing International Composite Materials Co., Ltd., the brand is ECS303HK-3-K;

[0035] Pentabromobenzyl polyacrylate: manufacturer is ICL Dead Sea Industries, brand name FR1025;

[0036] Hexaphenoxycyclotriphosphazene;

[0037] PBT: manufacturer is Xinjiang Lanshan Tunhe Co., Ltd., brand TH6100, intrinsic viscosity is 1.0;

[0038] SAS: The manufacturer is UMG, the brand is S351, the melt flow rate at 220℃ and 10kg load is 21cm 3 / 10min;

[0039] Silicone masterbatch: manufacturer is Dow Corning, brand name is HMB-1903, carrier resin is PC;

[0040] Silicone-acrylic acid type high weathering and impact modifier: manufacturer is Mitsubishi Rayon Co., Ltd., brand name is SX-006;

[0041] (2) adding glass fiber into a twin-screw extruder through a main feed port B, and simultaneously adding polypentabromobenzyl acrylate, hexaphenoxycyclotriphosphazene, PBT, SAS, silicone masterbatch and silicone-acrylic type high weather resistance and impact modifier into the twin-screw extruder through a main feed port A, and melt-extruded and granulated to obtain a PBT composite material that is resistant to low-temperature impact and resistant to wet and hot aging; wherein the speed of the twin-screw extruder is 450-600 rpm, and the temperature is 220-230°C.

[0042] The final prepared PBT composite material with low-temperature impact resistance and heat and humidity aging resistance is composed of 10 parts of glass fiber, 15 parts of polypentabromobenzyl acrylate, 4 parts of hexaphenoxycyclotriphosphazene, 100 parts of PBT, 8 parts of SAS, 1 part of silicone masterbatch and 5 parts of silicone-acrylic acid type high weather resistance and impact modifier by weight.

[0043] The CTI value of the PBT composite material that is resistant to low temperature impact and heat and humidity aging is 350V, and the notched impact strength at 23°C is 10.3kJ / m 2 , notched impact strength at -40℃ is 8kJ / m 2 , UL94 reaches V0 grade; after the PBT composite material with resistance to low temperature impact and heat and humidity aging is placed under the conditions of relative humidity of 85% and temperature of 85℃ for 240h, the notched impact strength retention rate at 23℃ is 80%, and the notched impact strength retention rate at -40℃ is 82%, and UL94 still reaches V0 grade.

[0044] Comparative Example 1

[0045] A method for preparing a PBT composite material is different from that of Example 1 in that hexaphenoxycyclotriphosphazene is replaced by an equal mass of polypentabromobenzyl acrylate (same as Example 1).

[0046] The final PBT composite material has a notched impact strength of 9.2 kJ / m at 23 °C. 2, notched impact strength at -40℃ is 5.4kJ / m 2 After the PBT composite material was placed under the conditions of relative humidity of 85% and temperature of 85℃ for 240h, the notched impact strength retention rate at 23℃ was 74% and the notched impact strength retention rate at -40℃ was 70%.

[0047] Compared with Example 1, the mechanical properties, low-temperature impact resistance, and moist heat aging resistance of the PBT composite material of Comparative Example 1 are significantly deteriorated. This is because although pentabromobenzyl polyacrylate has good compatibility with PBT, its excessive addition affects the continuity of PBT.

[0048] Comparative Example 2

[0049] A method for preparing a PBT composite material is different from Example 1 only in that polypentabromobenzyl acrylate is replaced by an equal mass of hexaphenoxycyclotriphosphazene.

[0050] The final PBT composite material has a notched impact strength of 6.5 kJ / m at 23 °C. 2 , notched impact strength at -40℃ is 4.5kJ / m 2 After the PBT composite material was placed under the conditions of relative humidity of 85% and temperature of 85℃ for 240h, the notched impact strength retention rate at 23℃ was 55%, and the notched impact strength retention rate at -40℃ was 45%.

[0051] Compared with Example 1, the mechanical properties, low-temperature impact resistance, and moist heat aging resistance of the PBT composite material of Comparative Example 2 are significantly deteriorated. This is because the carbon formation and flame retardant efficiency of hexaphenoxycyclotriphosphazene as a halogen-free flame retardant are far inferior to those of polypentabromobenzyl acrylate, and its compatibility with PBT is also far inferior to that of polypentabromobenzyl acrylate. Ultimately, the mechanical properties of the PBT composite material are deteriorated, and precipitation occurs under high temperature and high humidity conditions, thereby affecting the moist heat aging resistance of the PBT composite material.

[0052] Comparative Example 3

[0053] A method for preparing a PBT composite material is different from Example 1 only in that polypentabromobenzyl acrylate is replaced with an equal mass of brominated epoxy resin (manufacturer: Jiangsu Xingsheng Chemical Co., Ltd., brand EP-25K).

[0054] The final PBT composite material has a notched impact strength of 10.1 kJ / m at 23°C. 2 , notched impact strength at -40℃ is 6.2kJ / m 2After the PBT composite material was placed under the conditions of relative humidity of 85% and temperature of 85℃ for 240h, the notched impact strength retention rate at 23℃ was 73%, and the notched impact strength retention rate at -40℃ was 68%.

[0055] Compared with Example 1, the low-temperature impact resistance and moisture-heat aging resistance of the PBT composite material of Comparative Example 3 are significantly deteriorated. This is because brominated epoxy resin, as the most common halogen flame retardant, has a high cost-effectiveness. However, compared with polypentabromobenzyl acrylate, its compatibility with PBT is significantly poorer, resulting in a significant decrease in the mechanical properties of the composite material, especially the mechanical properties at low temperatures. In addition, the halogen group strength in the brominated epoxy resin is insufficient, and chain scission reactions are very likely to occur under high temperature and high humidity conditions, resulting in poor moisture-heat aging resistance of the composite material.

[0056] Example 2

[0057] A method for preparing a PBT composite material that is resistant to low-temperature impact and resistant to moist heat aging, comprising the following steps:

[0058] (1) Preparation of raw materials;

[0059] Glass fiber: The manufacturer is Chongqing International Composite Materials Co., Ltd., the brand is ECS303HK-3-K;

[0060] Pentabromobenzyl polyacrylate: manufacturer is ICL Dead Sea Industries, brand name FR1025;

[0061] Hexaphenoxycyclotriphosphazene;

[0062] PBT: manufacturer: Changchun Chemical (Jiangsu) Jiangsu Co., Ltd., brand: 1100-211X, intrinsic viscosity: 1.3;

[0063] SAS: The manufacturer is UMG, the brand is TW-15G, and the melt flow rate at 220℃ and 10kg load is 3cm 3 / 10min;

[0064] Silicone masterbatch: manufacturer is Dow Corning, brand name is HMB-1903, carrier resin is PC;

[0065] Silicone-acrylic acid type high weathering and impact modifier: manufacturer is Mitsubishi Rayon Co., Ltd., brand name is SX-006;

[0066] (2) adding glass fiber into a twin-screw extruder through a main feed port B, and simultaneously adding polypentabromobenzyl acrylate, hexaphenoxycyclotriphosphazene, PBT, SAS, silicone masterbatch and silicone-acrylic type high weather resistance and impact modifier into the twin-screw extruder through a main feed port A, and melt-extruded and granulated to obtain a PBT composite material that is resistant to low-temperature impact and resistant to wet and hot aging; wherein the speed of the twin-screw extruder is 450-600 rpm, and the temperature is 220-230°C.

[0067] The final prepared PBT composite material with low-temperature impact resistance and heat and humidity aging resistance is composed of 20 parts of glass fiber, 17 parts of polypentabromobenzyl acrylate, 5 parts of hexaphenoxycyclotriphosphazene, 100 parts of PBT, 10 parts of SAS, 1.5 parts of silicone masterbatch and 8 parts of silicone-acrylic acid type high weather resistance and impact modifier by weight.

[0068] The CTI value of PBT composite materials with low temperature impact resistance and heat and humidity aging resistance is 300V, and the notched impact strength at 23°C is 10.6kJ / m 2 , notched impact strength at -40℃ is 8.9kJ / m 2 , UL94 reaches V0 grade; after the PBT composite material with resistance to low temperature impact and moisture and heat aging was placed under the conditions of relative humidity of 85% and temperature of 85℃ for 240h, the notched impact strength retention rate at 23℃ was 79%, and the notched impact strength retention rate at -40℃ was 76%, and UL94 still reached V0 grade.

[0069] Example 3

[0070] A method for preparing a PBT composite material that is resistant to low-temperature impact and resistant to moist heat aging, comprising the following steps:

[0071] (1) Preparation of raw materials;

[0072] Glass fiber: The manufacturer is Chongqing International Composite Materials Co., Ltd., the brand is ECS303HK-3-K;

[0073] Pentabromobenzyl polyacrylate: manufacturer is ICL Dead Sea Industries, brand name FR1025;

[0074] Hexaphenoxycyclotriphosphazene;

[0075] PBT: manufacturer: Changchun Chemical (Jiangsu) Jiangsu Co., Ltd., brand: 1200-211D, intrinsic viscosity: 0.75;

[0076] SAS: The manufacturer is UMG, the brand is E259B, the melt flow rate at 220℃ and 10kg load is 15cm 3 / 10min;

[0077] Silicone masterbatch: manufacturer is Dow Corning, brand name is HMB-1903, carrier resin is PC;

[0078] Silicone-acrylic acid type high weathering and impact modifier: manufacturer is Mitsubishi Rayon Co., Ltd., brand name is SX-006;

[0079] (2) adding glass fiber into a twin-screw extruder through a main feed port B, and simultaneously adding polypentabromobenzyl acrylate, hexaphenoxycyclotriphosphazene, PBT, SAS, silicone masterbatch and silicone-acrylic type high weather resistance and impact modifier into the twin-screw extruder through a main feed port A, and melt-extruded and granulated to obtain a PBT composite material that is resistant to low-temperature impact and resistant to wet and hot aging; wherein the speed of the twin-screw extruder is 450-600 rpm, and the temperature is 220-230°C.

[0080] The final prepared PBT composite material with low-temperature impact resistance and heat and humidity aging resistance consists of 30 parts of glass fiber, 18 parts of polypentabromobenzyl acrylate, 6 parts of hexaphenoxycyclotriphosphazene, 100 parts of PBT, 20 parts of SAS, 1 part of silicone masterbatch and 5 parts of silicone-acrylic acid type high weather resistance and impact modifier, calculated by weight.

[0081] The CTI value of PBT composite materials with low temperature impact resistance and heat and humidity aging resistance is 350V, and the notched impact strength at 23°C is 9kJ / m 2 , notched impact strength at -40℃ is 7.5kJ / m 2 , UL94 reaches V0 grade; after the PBT composite material with resistance to low temperature impact and moisture and heat aging is placed under the conditions of relative humidity of 85% and temperature of 85℃ for 240h, the notched impact strength retention rate at 23℃ is 82%, and the notched impact strength retention rate at -40℃ is 85%, and UL94 still reaches V0 grade.

[0082] Example 4

[0083] A method for preparing a PBT composite material that is resistant to low-temperature impact and resistant to moist heat aging, comprising the following steps:

[0084] (1) Preparation of raw materials;

[0085] Glass fiber: The manufacturer is Chongqing International Composite Materials Co., Ltd., the brand is ECS303HK-3-K;

[0086] Pentabromobenzyl polyacrylate: manufacturer is ICL Dead Sea Industries, brand name FR1025;

[0087] Hexaphenoxycyclotriphosphazene;

[0088] PBT: Manufacturer: Sinopec Yizheng Chemical Fiber, brand: GX112, intrinsic viscosity: 0.82;

[0089] SAS: The manufacturer is UMG, the brand is TW-15G, and the melt flow rate at 220℃ and 10kg load is 3cm 3 / 10min;

[0090] Silicone masterbatch: The manufacturer is Dow Corning, the brand is HMB-1903, and the carrier resin is PC;

[0091] Silicone-acrylic acid type high weathering and impact modifier: manufacturer is Mitsubishi Rayon Co., Ltd., brand name is SX-006;

[0092] (2) adding glass fiber into a twin-screw extruder through a main feed port B, and simultaneously adding polypentabromobenzyl acrylate, hexaphenoxycyclotriphosphazene, PBT, SAS, silicone masterbatch and silicone-acrylic type high weather resistance and impact modifier into the twin-screw extruder through a main feed port A, and melt-extruded and granulated to obtain a PBT composite material that is resistant to low-temperature impact and resistant to wet and hot aging; wherein the speed of the twin-screw extruder is 450-600 rpm, and the temperature is 220-230°C.

[0093] The final prepared PBT composite material with low-temperature impact resistance and heat and humidity aging resistance is composed of 10 parts of glass fiber, 20 parts of polypentabromobenzyl acrylate, 5 parts of hexaphenoxycyclotriphosphazene, 100 parts of PBT, 10 parts of SAS, 2 parts of silicone masterbatch and 6 parts of silicone-acrylic acid type high weather resistance and impact modifier, by weight.

[0094] The CTI value of PBT composite materials with low temperature impact resistance and heat and humidity aging resistance is 300V, and the notched impact strength at 23°C is 9.5kJ / m 2 , notched impact strength at -40℃ is 7.7kJ / m 2 , UL94 reaches V0 grade; after the PBT composite material with resistance to low temperature impact and moisture and heat aging is placed under the conditions of relative humidity of 85% and temperature of 85℃ for 240h, the notched impact strength retention rate at 23℃ is 80%, and the notched impact strength retention rate at -40℃ is 77%, and UL94 still reaches V0 grade.

[0095] Example 5

[0096] A method for preparing a PBT composite material that is resistant to low-temperature impact and resistant to moist heat aging, comprising the following steps:

[0097] (1) Preparation of raw materials;

[0098] Glass fiber: The manufacturer is Chongqing International Composite Materials Co., Ltd., the brand is ECS303HK-3-K;

[0099] Pentabromobenzyl polyacrylate: manufacturer is ICL Dead Sea Industries, brand name FR1025;

[0100] Hexaphenoxycyclotriphosphazene;

[0101] PBT: Manufacturer: Nantong Xingchen Synthetic Materials Co., Ltd., brand: 1120, intrinsic viscosity: 1.2;

[0102] SAS: The manufacturer is UMG, the brand is E259B, the melt flow rate at 220℃ and 10kg load is 15cm 3 / 10min;

[0103] Silicone masterbatch: manufacturer is Dow Corning, brand name is HMB-1903, carrier resin is PC;

[0104] Silicone-acrylic acid type high weathering and impact modifier: manufacturer is Mitsubishi Rayon Co., Ltd., brand name is SX-006;

[0105] (2) adding glass fiber into a twin-screw extruder through a main feed port B, and simultaneously adding polypentabromobenzyl acrylate, hexaphenoxycyclotriphosphazene, PBT, SAS, silicone masterbatch and silicone-acrylic type high weather resistance and impact modifier into the twin-screw extruder through a main feed port A, and melt-extruded and granulated to obtain a PBT composite material that is resistant to low-temperature impact and resistant to wet and hot aging; wherein the speed of the twin-screw extruder is 450-600 rpm, and the temperature is 220-230°C.

[0106] The final prepared PBT composite material with low-temperature impact resistance and heat and humidity aging resistance is composed of 30 parts of glass fiber, 15 parts of polypentabromobenzyl acrylate, 6 parts of hexaphenoxycyclotriphosphazene, 100 parts of PBT, 15 parts of SAS, 1.5 parts of silicone masterbatch and 7 parts of silicone-acrylic acid type high weather resistance and impact modifier by weight.

[0107] The CTI value of PBT composite materials with low temperature impact resistance and heat and humidity aging resistance is 300V, and the notched impact strength at 23°C is 8.5kJ / m 2 , notched impact strength at -40℃ is 7.5kJ / m 2 , UL94 reaches V0 grade; after the PBT composite material with resistance to low temperature impact and heat and humidity aging was placed under the conditions of relative humidity of 85% and temperature of 85℃ for 240h, the notched impact strength retention rate at 23℃ was 83%, and the notched impact strength retention rate at -40℃ was 78%, and UL94 still reached V0 grade.

Claims

1. A PBT composite material resistant to low temperature impact and moisture and heat aging, characterized in that: The invention comprises, by weight, 100 parts of PBT, 8-20 parts of SAS, 1-2 parts of silicone masterbatch, 5-8 parts of silicone toughening agent, 15-20 parts of polypentabromobenzyl acrylate, 4-6 parts of phosphazene flame retardant and 10-30 parts of glass fiber, wherein the carrier resin of the silicone masterbatch is PC.

2. A PBT composite material resistant to low temperature impact and moisture and heat aging according to claim 1, characterized in that: The intrinsic viscosity of PBT is 0.8-1.

3.

3. The PBT composite material resistant to low temperature impact and moisture and heat aging according to claim 1, characterized in that: The melt flow rate of SAS at 220°C and 10kg load is 3-21cm 3 / 10min.

4. The PBT composite material resistant to low temperature impact and moisture and heat aging according to claim 1, characterized in that: The silicone-based toughening agent is a silicone-acrylic type highly weather-resistant and impact-resistant modifier.

5. The PBT composite material resistant to low temperature impact and moisture and heat aging according to claim 1, characterized in that: The phosphazene flame retardant is hexaphenoxy cyclotriphosphazene.

6. A PBT composite material resistant to low temperature impact and moisture and heat aging according to any one of claims 1 to 5, characterized in that: The CTI value of PBT composite materials resistant to low temperature impact and heat and humidity aging is 300-350V, and the notched impact strength at 23°C is 8.5-10.6kJ / m 2 , notched impact strength at -40°C is 7.5-8.9 kJ / m 2 , UL94 reaches V0 grade. After being placed under the conditions of relative humidity of 85% and temperature of 85℃ for 240h, the notched impact strength retention rate at 23℃ is more than 79%, and the notched impact strength retention rate at -40℃ is more than 76%. UL94 still reaches V0 grade.

7. A method for preparing a PBT composite material resistant to low temperature impact and resistant to moist heat aging as claimed in any one of claims 1 to 6, characterized in that: The glass fiber is added into the twin-screw extruder through the main feed port B, and the other components are added into the twin-screw extruder through the main feed port A, and melt-extruded into granules, wherein the speed of the twin-screw extruder is 450-600 rpm and the temperature is 220-230°C.