Heat shrink terminal sleeve material, method of making same, and heat shrink terminal

Abstract

The application discloses a sleeve material for heat-shrinkable terminals, which is prepared from the following raw materials in parts by weight: 100 parts of polyetherimide, 10-30 parts of polycarbonate, 20-40 parts of trizinc trimellitate, and 2-8 parts of nano-zinc stannate. The application also discloses a preparation method of the sleeve material for heat-shrinkable terminals and heat-shrinkable terminals prepared therefrom. The sleeve material for heat-shrinkable terminals has the characteristics of high strength and transparency, low water absorption, excellent high-temperature resistance and flame resistance, and good processability, and has better comprehensive performance.

Description

Technical Field

[0001] This invention relates to the field of heat-shrinkable terminal technology, specifically to a sleeve material for heat-shrinkable terminals, its preparation method, and heat-shrinkable terminals. Background Technology

[0002] With the rapid development of industries such as power, transportation, new energy vehicles, and communications, the application of cables has permeated all aspects of society. Cable connection protection has also evolved from the initial wrapping with insulating tape to the use of connectors. Among connectors, heat-shrinkable terminals are increasingly favored by various industries due to their excellent waterproof performance and simple and convenient usage. Heat-shrinkable terminals mainly consist of an internal metal component and an outer heat-shrinkable tubing. The performance of the outer heat-shrinkable tubing determines the operating environment and conditions of the heat-shrinkable terminal; therefore, the tubing material used for heat-shrinkable terminals is a topic worthy of research.

[0003] Currently, commonly used insulating sleeves for heat-shrinkable terminals are mainly made of polyolefin materials, which have various problems such as poor transparency, insufficient temperature resistance, low flame retardancy, and low strength, limiting the application of the products. Chinese patent application number CN201911007232.9 discloses a method for manufacturing heat-shrinkable tubing for heat-shrinkable terminals. The composition of the terminal tube body is as follows: 65 to 75 parts of perfluoropropylene, 10 to 20 parts of ethylene glycol-modified polyethylene terephthalate, 3 to 6 parts of polybutylene terephthalate, 10 to 20 parts of phosphate ester flame retardant, and 0.05 to 0.09 parts of lubricant. This heat-shrinkable terminal tube has good flame retardant properties, but the transparency of the heat-shrinkable terminals is still relatively poor, and the presence of halogens in the material also has a certain impact on environmental performance.

[0004] Polyetherimide (PEI) is a specialty engineering plastic, an amber-colored transparent solid with excellent mechanical strength, resistance to high and low temperatures, electrical insulation properties, and radiation resistance. It has an oxygen index of 47%, a UL94-V-0 flammability rating, and a heat distortion temperature of 198–208°C. It can be used continuously at 160–180°C, with a maximum permissible intermittent use temperature of 200°C, making it an ideal material for manufacturing heat-shrink tubing. However, PEI has high processing temperatures, poor processing flowability, high water absorption, insufficient transparency, and high cost, limiting its application in heat-shrinkable terminal tubing materials.

[0005] Chinese patent CN105778092A discloses a polyetherimide high-temperature heat shrink tubing. This tubing is prepared from a mixture of 1,3-bis(3-aminophenoxy)benzene, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, and 4,4-oxophthalic anhydride, comprising the following steps: 1. Preparing a diamine solution; 2. Preparing a dianhydride solution; 3. Preparing a polyamic acid solution; 4. Preparing a glass plate containing a polyetherimide film; 5. Preparing a dried polyetherimide film; 6. Preparing a glass tube containing a polyetherimide tube; 7. Preparing the polyetherimide high-temperature heat shrink tubing. While this patent avoids the drawbacks of high processing temperature and poor flowability of PEI (polyetherimide), it still suffers from complex manufacturing processes, insufficient product transparency, and inadequate water resistance and flame retardancy. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a sleeve material for heat shrink terminals. The sleeve material has high strength and transparency, low water absorption, excellent high temperature resistance and flame retardancy, and good processing performance, and has better overall performance.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0008] The present invention provides a heat-shrinkable terminal sleeve material, which is prepared from the following raw materials in parts by weight: 100 parts of polyetherimide (PEI), 10-30 parts of polycarbonate (PC), 20-40 parts of zinc trimellitate (TOTM), and 2-8 parts of nano zinc stannate (ZS).

[0009] PEI possesses good high-temperature resistance and flame retardant properties, but its high processing temperature and poor processing fluidity make it unsuitable as a heat-shrinkable terminal sleeve material due to its high water absorption, insufficient transparency, and excessive cost. To overcome these shortcomings, the inventors discovered that using PC and TOTM as multifunctional composite modifiers with plasticizing and water-resistant properties can solve these technical problems. Firstly, since both PC and TOTM contain benzene rings, and PEI also contains benzene rings, the composite modifier exhibits good compatibility with PEI. Secondly, PC is a polymer material with excellent transparency; adding it to PEI significantly improves its transparency. TOTM, being a small-molecule liquid, can penetrate the intermolecular space of PEI, surrounding the hydrophilic imide groups and reducing its water absorption. Thirdly, the composite modifiers PC and TOTM have low melting points and good processing fluidity. TOTM, being a small-molecule liquid, increases the intermolecular distance of PEI, lowering its melting temperature, increasing processing fluidity, and improving toughness.

[0010] To further improve the flame retardant properties of PEI, the inventors selected ZS as a flame retardant and added it to PEI. ZS is a highly efficient and environmentally friendly flame retardant. By controlling its particle size within the range of 50-100nm, ZS not only has flame retardant properties, but also enhances and improves heat resistance due to its nano-size effect and heterogeneous nucleation effect.

[0011] Since composite modification can lower the melting point of PEI and improve its processing fluidity, impact resistance, transparency and water absorption, while nano ZS has flame retardant and reinforcing effects, introducing composite modifiers and ZS into PEI can produce heat shrinkable terminal sleeve materials with improved processing fluidity, increased toughness, improved transparency, high temperature resistance and high flame retardancy.

[0012] Furthermore, the particle size of the nano-zinc stannate is 50-100 nm.

[0013] The present invention also provides a method for preparing a heat-shrinkable terminal sleeve material, comprising the following steps:

[0014] Zinc stannate and zinc trimellitate were ball-milled to obtain a mixture of nano zinc stannate and zinc trimellitate.

[0015] The mixture of nano-zinc stannate and zinc trimellitate is mixed with polyetherimide and polycarbonate to obtain a precursor; and

[0016] The precursor is extruded and granulated using an extruder to obtain the heat-shrinkable terminal sleeve material.

[0017] In this invention, ZS and TOTM are ball-milled together. During the ball milling process, ZS is fully wetted and coated by TOTM and forms coordination bonds, thereby making ZS uniformly dispersed in PEI, which is beneficial to improving the flame retardant properties of PEI.

[0018] Furthermore, the ball milling time for zinc stannate and zinc trimellitate is 12-24 hours, and the ball milling speed is 100-500 rpm.

[0019] Furthermore, the nano-zinc stannate obtained after ball milling has a particle size of 50-100 nm.

[0020] Further, the preparation method of the precursor is as follows: at room temperature, the mixture of nano zinc stannate and trizinc trimellitate is mixed with dry polyetherimide and polycarbonate at a speed of 450-650 rpm for 1-5 minutes, then mixed at a speed of 950-1200 rpm for 1-3 minutes, then the mixing is stopped and the mixture is allowed to stand for 3-10 minutes to obtain the precursor.

[0021] Furthermore, the drying conditions for the polyetherimide are: 160°C under vacuum for 3 hours; and the drying conditions for the polycarbonate are: 105°C under vacuum for 4 hours.

[0022] Furthermore, the temperature parameters of the extruder are as follows: Zone 1 180℃-200℃, Zone 2 230℃-260℃, Zone 3 270℃-300℃, Zone 4 310℃-330℃, Zone 5 340℃-350℃, Zone 6 360℃-370℃, and die head 355℃-365℃; the screw speed of the extruder is 100rpm-200rpm.

[0023] The present invention also provides a heat-shrinkable terminal, including a bare terminal tube and a heat-shrinkable insulating sleeve, wherein the heat-shrinkable insulating sleeve is prepared from the sleeve material for heat-shrinkable terminals.

[0024] Furthermore, the heat-shrinkable insulating sleeve has an overall dumbbell-shaped structure that is thinner in the middle and thicker at both ends. The bare terminal tube is located inside the heat-shrinkable insulating sleeve and in the middle section. It is sealed and connected to the heat-shrinkable insulating sleeve by polyamide (PA) hot melt adhesive.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. The heat-shrinkable terminal tubing material of the present invention has the characteristics of high strength and transparency, low water absorption, excellent high temperature resistance and flame retardancy, and good processing performance. Compared with other heat-shrinkable tubing materials, the tubing material of the present invention has better overall performance.

[0027] 2. The ZS used in this invention is a high-temperature flame retardant, and the TOTM used is a high-boiling-point plasticizer, so both have stable performance during processing. Detailed Implementation

[0028] The present invention will be further described below with reference to specific embodiments, so that those skilled in the art can better understand and implement the present invention, but the embodiments are not intended to limit the present invention.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0030] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the materials and reagents used are commercially available.

[0031] Example 1

[0032] Five parts of ZS and 30 parts of TOTM were ball-milled in a planetary ball mill for 24 hours to obtain a mixture of ZS and TOTM with a particle size of 53 nanometers. PEI was dried in a vacuum drying oven at 160℃ for 3 hours. PC was dried in a vacuum drying oven at 105℃ for 4 hours. Then, the mixture of nano-ZS and TOTM was mixed with 100 parts of dried PEI and 20 parts of dried PC in a high-speed mixer at room temperature, first at 450 rpm for 2 minutes, then at 1000 rpm for 1 minute. Mixing was then stopped and the mixture was allowed to stand for 5 minutes to obtain the precursor. The precursor was then extruded and granulated using a twin-screw extruder to obtain the heat-shrinkable terminal sleeve material. The extruder temperature parameters were: Zone 1 190℃, Zone 2 240℃, Zone 3 280℃, Zone 4 320℃, Zone 5 345℃, Zone 6 365℃, and the die head 360℃; the extruder screw speed was 150 rpm.

[0033] Example 2

[0034] Two parts ZS and 20 parts TOTM were ball-milled in a planetary ball mill for 12 hours to obtain a mixture of ZS and TOTM with a particle size of 85 nanometers. PEI was dried in a vacuum drying oven at 160℃ for 3 hours. PC was dried in a vacuum drying oven at 105℃ for 4 hours. Then, the mixture of nano-ZS and TOTM was mixed with 100 parts of dried PEI and 30 parts of dried PC in a high-speed mixer at room temperature, first at 550 rpm for 3 minutes, then at 1100 rpm for 1 minute. Mixing was then stopped and the mixture was allowed to stand for 10 minutes to obtain the precursor. The precursor was then extruded and granulated using a twin-screw extruder to obtain the heat-shrinkable terminal sleeve material. The extruder temperature parameters were: Zone 1 180℃, Zone 2 240℃, Zone 3 270℃, Zone 4 310℃, Zone 5 340℃, Zone 6 360℃, and die head 355℃; the extruder screw speed was 200 rpm.

[0035] Example 3

[0036] Eight parts of ZS and 40 parts of TOTM were ball-milled in a planetary ball mill for 24 hours to obtain a mixture of ZS and TOTM with a particle size of 72 nanometers. PEI was dried in a vacuum drying oven at 160℃ for 3 hours. PC was dried in a vacuum drying oven at 105℃ for 4 hours. Then, the mixture of nano-ZS and TOTM was mixed with 100 parts of dried PEI and 10 parts of dried PC in a high-speed mixer at room temperature, first at 650 rpm for 4 minutes, then at 1100 rpm for 2 minutes. Mixing was then stopped and the mixture was allowed to stand for 8 minutes to obtain the precursor. The precursor was then extruded and granulated using a twin-screw extruder to obtain the heat-shrinkable terminal sleeve material. The extruder temperature parameters were: Zone 1 200℃, Zone 2 260℃, Zone 3 300℃, Zone 4 330℃, Zone 5 350℃, Zone 6 370℃, and die head 365℃; the extruder screw speed was 100 rpm.

[0037] Comparative Example 1

[0038] PEI was dried in a vacuum drying oven at 160℃ for 3 hours, and then extruded and granulated using a twin-screw extruder to obtain the tubing material for heat-shrinkable terminals. The extruder temperature parameters were: Zone 1 200℃, Zone 2 260℃, Zone 3 300℃, Zone 4 330℃, Zone 5 360℃, Zone 6 380℃, and die head 360℃; the extruder screw speed was 120 rpm.

[0039] Comparative Example 2

[0040] Five parts of ZS and 25 parts of TOTM were ball-milled in a planetary ball mill for 20 hours to obtain a mixture of ZS and TOTM with a particle size of 64 nanometers. PEI was dried in a vacuum drying oven at 160℃ for 3 hours. Then, the mixture of nano-ZS and TOTM was mixed with 100 parts of dried PEI in a high-speed mixer at room temperature, first at 450 rpm for 2 minutes, then at 1000 rpm for 1 minute. Mixing was then stopped and the mixture was allowed to stand for 5 minutes to obtain the precursor. The precursor was then extruded and granulated using a twin-screw extruder to obtain the tubing material for heat-shrinkable terminals. The extruder temperature parameters were: Zone 1 200℃, Zone 2 250℃, Zone 3 290℃, Zone 4 330℃, Zone 5 360℃, Zone 6 380℃, and die head 370℃; the extruder screw speed was 180 rpm.

[0041] Comparative Example 3

[0042] PEI was dried in a vacuum drying oven at 160℃ for 3 hours; PC was dried in a vacuum drying oven at 105℃ for 4 hours; then 23 parts of TOTM, 100 parts of dried PEI, and 26 parts of dried PC were mixed in a high-speed mixer at room temperature at 550 rpm for 3 minutes, then at 1100 rpm for 1 minute, and then the mixing was stopped and allowed to stand for 10 minutes to obtain the precursor; the precursor was then extruded and granulated by a twin-screw extruder to obtain the heat-shrinkable terminal sleeve material. The temperature parameters of the extruder were: Zone 1 180℃, Zone 2 250℃, Zone 3 280℃, Zone 4 310℃, Zone 5 340℃, Zone 6 360℃, and the die head 355℃; the screw speed of the extruder was 130 rpm.

[0043] Comparative Example 4

[0044] Six parts of ZS and 30 parts of anhydrous ethanol were ball-milled in a planetary ball mill for 15 hours, filtered, and dried to obtain ZS with a particle size of 81 nanometers. PEI was dried in a vacuum drying oven at 160℃ for 3 hours. PC was dried in a vacuum drying oven at 105℃ for 4 hours. Then, nano ZS was mixed with 100 parts of dried PEI and 22 parts of dried PC in a high-speed mixer at room temperature, first at 650 rpm for 2 minutes, then at 1100 rpm for 2 minutes. Mixing was then stopped and the mixture was allowed to stand for 5 minutes to obtain the precursor. The precursor was then extruded and granulated using a twin-screw extruder to obtain the heat-shrinkable terminal sleeve material. The extruder temperature parameters were: Zone 1 200℃, Zone 2 260℃, Zone 3 300℃, Zone 4 330℃, Zone 5 350℃, Zone 6 370℃, and die head 365℃; the extruder screw speed was 160 rpm.

[0045] Comparative Example 5

[0046] PEI was dried in a vacuum drying oven at 160℃ for 3 hours; PC was dried in a vacuum drying oven at 105℃ for 4 hours; then 4 parts ZS, 32 parts TOTM, 100 parts dried PEI, and 28 parts dried PC were mixed in a high-speed mixer at room temperature at 600 rpm for 3 minutes, then at 1100 rpm for 2 minutes, and then the mixing was stopped and allowed to stand for 8 minutes to obtain the precursor; the precursor was then extruded and granulated by a twin-screw extruder to obtain the heat-shrinkable terminal sleeve material. The temperature parameters of the extruder were: Zone 1 180℃, Zone 2 230℃, Zone 3 270℃, Zone 4 310℃, Zone 5 340℃, Zone 6 365℃, and the die head 360℃; the screw speed of the extruder was 170 rpm.

[0047] Performance testing

[0048] The oxygen index (according to GB / T2406), heat distortion temperature (1.8 MPa), light transmittance (sample thickness 5 mm), impact resistance (pendulum energy 22 J), melt flow rate (340℃ / 6.6 kg), and water absorption (according to ASTM D570, 24 hours) of the heat shrinkable terminal sleeve materials prepared in the examples and comparative examples were tested, and the results are shown in Table 1.

[0049] Table 1 Performance test results of heat-shrinkable terminal sleeve materials in the examples and comparative examples

[0050]

[0051]

[0052] As can be seen from the results in Table 1, compared with the sleeve material of the comparative example, the sleeve material of the embodiment has better high temperature resistance and flame retardancy, higher strength and transparency, lower water absorption, higher melt flow rate, better processing performance, and better overall performance.

[0053] The above-described embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. A sleeve material for heat-shrinkable terminals, characterized in that, It is prepared from the following raw materials in parts by weight: 100 parts of polyetherimide, 10-30 parts of polycarbonate, 20-40 parts of trioctyl trimellitate, and 2-8 parts of nano zinc stannate. The method for preparing a heat-shrinkable terminal sleeve material includes the following steps: Zinc stannate and trioctyl trimellitate were ball-milled to obtain a mixture of nano-zinc stannate and trioctyl trimellitate; the particle size of the nano-zinc stannate obtained after ball milling was 50-100 nm. The mixture of the nano-zinc stannate and trioctyl trimellitate was mixed with polyetherimide and polycarbonate to obtain the precursor; and The precursor is extruded and granulated using an extruder to obtain the heat-shrinkable terminal sleeve material.

2. The method for preparing a heat-shrinkable terminal sleeve material according to claim 1, characterized in that, Includes the following steps: Zinc stannate and trioctyl trimellitate were ball-milled to obtain a mixture of nano zinc stannate and trioctyl trimellitate. The mixture of the nano-zinc stannate and trioctyl trimellitate was mixed with polyetherimide and polycarbonate to obtain the precursor; and The precursor is extruded and granulated using an extruder to obtain the heat-shrinkable terminal sleeve material.

3. The method for preparing a heat-shrinkable terminal sleeve material according to claim 2, characterized in that, The ball milling time for zinc stannate and trioctyl trimellitate is 12-24 hours, and the ball milling speed is 100-500 rpm.

4. The method for preparing a heat-shrinkable terminal sleeve material according to claim 2, characterized in that, The precursor is prepared as follows: at room temperature, a mixture of nano zinc stannate and trioctyl trimellitate is mixed with dry polyetherimide and polycarbonate at a speed of 450-650 rpm for 1-5 minutes, then mixed at a speed of 950-1200 rpm for 1-3 minutes, and then the mixing is stopped and allowed to stand for 3-10 minutes to obtain the precursor.

5. The method for preparing a heat-shrinkable terminal sleeve material according to claim 4, characterized in that, The drying conditions for the polyetherimide are: 160°C under vacuum for 3 hours; the drying conditions for the polycarbonate are: 105°C under vacuum for 4 hours.

6. The method for preparing a heat-shrinkable terminal sleeve material according to claim 2, characterized in that, The temperature parameters of the extruder are as follows: Zone 1 180℃-200℃, Zone 2 230℃-260℃, Zone 3 270℃-300℃, Zone 4 310℃-330℃, Zone 5 340℃-350℃, Zone 6 360℃-370℃, and Die head 355℃-365℃; the screw speed of the extruder is 100rpm-200rpm.

7. A heat-shrinkable terminal, comprising a bare terminal tube and a heat-shrinkable insulating sleeve, characterized in that, The heat-shrinkable insulating sleeve is prepared from the heat-shrinkable terminal sleeve material as described in claim 1.

8. A heat-shrinkable terminal according to claim 7, characterized in that, The heat-shrinkable insulating sleeve has a dumbbell-shaped structure that is thinner in the middle and thicker at both ends. The bare terminal tube is located inside the heat-shrinkable insulating sleeve and in the middle section. It is sealed and connected to the heat-shrinkable insulating sleeve by polyamide hot melt adhesive.

Images