High-temperature low-attenuation polypropylene insulating material and preparation method thereof

Abstract

The invention provides a high-temperature low-attenuation polypropylene insulating material and a preparation method thereof, and belongs to the field of high-molecular polymers. The polypropylene composite material comprises polypropylene and concentrated master batch, the concentrated master batch contains polypropylene, an antioxidant, a nucleating agent and white mineral oil. The antioxidant comprises a semi-hindered phenol (capturing free radicals), sulfur (decomposing hydroperoxide) and copper damage prevention (inhibiting catalytic oxidation of copper ions) composite system, the three antioxidants form a synergistic effect, and the thermal oxidation resistance of the material can be remarkably improved. According to the invention, the high-temperature low-attenuation polypropylene insulation material with high temperature resistance grade, low attenuation at high temperature and good extrusion moldability is prepared through a composite antioxidant system, nucleating agent regulation and control and a step-by-step granulation process; the cable especially meets the requirements for new energy automobile cables at present.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of high molecular polymers, and particularly relates to a high-temperature low-attenuation polypropylene insulating material and a preparation method thereof. BACKGROUND

[0002] With the rapid development of 5G and new energy vehicles, the communication cable industry has higher and higher requirements for wires, mainly in terms of heat resistance and signal transmission. Automobile cables are specially designed and produced according to the needs of automobiles. With the development of intelligent networked vehicles and autonomous driving technology, the automobile communication system needs to continuously improve the transmission rate. High-speed cables are cables that connect communication equipment, using silver-plated conductors and foamed insulating core wires as materials. In order to realize high-speed, stable, reliable and low-latency data transmission between so many newly added modules, high-speed data transmission systems have become more important than ever.

[0003] In almost all cases, the heat resistance temperature requirement of the cable on the automobile is above B-T100 level, and at least polypropylene (PP) or crosslinked polyethylene (XLPE) can meet this temperature requirement, and polyethylene (PE) is generally not allowed to be applied to automobile cables.

[0004] Recently, the International Organization for Standardization (ISO) published the ISO 19642-11:2023 standard for vehicle radio frequency coaxial cables for the first time. The standard covers 22 types of coaxial cables to meet the needs of different locations and functions in vehicles. Foaming is an effective means to reduce the dielectric constant and ring loss of the medium material, thereby reducing the product size, reducing the attenuation, improving the effective transmission distance, and improving the propagation rate.

[0005] However, some domestic customers have significantly stricter requirements for the high-temperature attenuation of the wire than the ISO 19642-11:2023 standard, which puts higher requirements on the room temperature dielectric properties and high-temperature dielectric properties of the material.

[0006] In summary, in order to achieve high temperature resistance, high temperature low attenuation, and good extrusion molding, the existing system needs to be redeveloped, and impurity components, especially polar substances, in the material composition need to be reduced as much as possible. High-purity PP substrate is selected as the core, and attention needs to be paid to the combination and collocation of nucleating agents and antioxidant systems to achieve good compatibility. SUMMARY

[0007] The purpose of the present application is to provide a high-temperature low-attenuation polypropylene insulating material, which contains the following components by mass fraction:

[0008] Polypropylene 80-95

[0009] Concentrated master batch 5-20;

[0010] The concentrated master batch is composed of the following components:

[0011]

[0012] Preferably, the antioxidant is at least one of a semi-hindered phenolic antioxidant, a sulfur-based antioxidant, and a copper poison prevention antioxidant.

[0013] Preferably, the antioxidant consists of

[0014] semi-hindered phenolic antioxidant 2-2.5

[0015] sulfur-based antioxidant 2-2.5

[0016] copper poison prevention antioxidant 1.5-2.

[0017] Preferably, the polypropylene is a homopolymer polypropylene.

[0018] Another object of the present application is to provide a method for preparing the aforementioned high-temperature low-attenuation polypropylene insulation material, comprising the following steps:

[0019] S1: uniformly mix the polypropylene in the concentrated master batch with white mineral oil for use, to obtain granules;

[0020] S2: premix the antioxidant and the nucleating agent into a powder;

[0021] S3: uniformly mix the granules and the powder, and then extrude and granulate, to obtain a concentrated master batch;

[0022] S4: uniformly mix the concentrated master batch with the remaining portion of the polypropylene, and then extrude and granulate again, to obtain a high-temperature low-attenuation polypropylene insulation material.

[0023] Preferably, in the step S3, the extrusion temperature during the extrusion and granulation is controlled between 190-210°C, and the main motor speed of the extruder is 300-500 rpm / min.

[0024] Preferably, in the step S4, the extrusion temperature during the extrusion and granulation is controlled between 190-210°C, and the main motor speed of the extruder is 300-500 rpm / min.

[0025] The present application selects a PP base material with higher purity and lower ash content. Compared with PE materials, PP materials have better rigidity and high-temperature resistance, and can exhibit better mechanical properties and durability in automotive applications. The presence of ash can cause the ionization of impurities inside the PP material, thereby increasing the dielectric loss of the PP. In high-frequency applications, dielectric loss is an important factor affecting cable attenuation, and a significant increase in dielectric loss at high frequencies can significantly reduce signal transmission quality. A PP base material with higher purity and lower ash content can better maintain the transmission quality of the signal.

[0026] The present application adds nucleating agent. The nucleating agent can improve the crystal structure of PP, especially beta nucleating agent. After adding, the medium loss of PP can be further reduced, and the wire extrusion performance of the material is improved. PP is prone to flatness during direct high-temperature extrusion. After adding the nucleating agent, the wire ovality is obviously improved.

[0027] The present application preferably uses an antioxidant combination system. The long-term aging performance of PP is improved to meet the requirements of 125 degree automobile wire temperature grade.

[0028] Overall, the present application uses polypropylene as the base material (80-95%), which meets the basic requirements of insulation materials for the insulation and mechanical properties of the base material. By using the composite system of "main polypropylene and concentrated masterbatch", the antioxidant, nucleating agent and other functional additives are concentrated in the masterbatch, which can improve the uniformity of the additives and avoid the problem of local high concentration or poor dispersion caused by direct addition. This is a common and effective method to improve the effect of additives in plastic processing.

[0029] The antioxidant used in the present application is a composite system of semi-hindered phenolic (free radical trapping), sulfur (hydrogen peroxide decomposition), and copper resistance (copper ion catalytic oxidation inhibition). The three types of antioxidants form a synergistic effect, which can significantly improve the thermal oxidation resistance of the material. The "copper resistance" design takes into account the actual scenario where the insulation material may come into contact with copper wires, and has strong practicality.

[0030] The addition of nucleating agent can optimize the crystalline structure of polypropylene (such as refining the grain size and increasing the crystallinity), which helps to improve the heat resistance (such as heat distortion temperature) and mechanical stability of the material, and matches the "high temperature" performance requirements.

[0031] White mineral oil as a dispersing agent can reduce the interfacial tension between the additive and polypropylene, and assist the uniform dispersion of the antioxidant and nucleating agent in the masterbatch. Low addition amount avoids negative impact on the performance of the base material.

[0032] In terms of process, the present application uses a "two-step granulation" process: first, prepare a concentrated masterbatch (concentrate the dispersing agent), then mix and granulate with the remaining polypropylene. By dispersing step by step, the additive is uniformly distributed in the final product, solving the dispersion problem when mixing high proportion of base material with low proportion of additive. The process parameters of the present application are suitable for the characteristics of polypropylene: the melting temperature of polypropylene is about 160-170℃, and 190-210℃ can ensure complete melting and avoid high temperature degradation; the rotation speed of 300-500rpm can provide sufficient shear force to promote uniform mixing of materials. The parameter setting has practicality.

[0033] The present application prepares a high-temperature low-attenuation polypropylene insulation material with high temperature resistance, low attenuation at high temperature and good extrusion molding property through the composite antioxidant system, nucleating agent regulation and step-by-step granulation process. It particularly meets the current requirements for new energy vehicle cables. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 DSC graph of Comparative Example 1;

[0035] Figure 2 DSC graph of Comparative Example 2. DETAILED DESCRIPTION

[0036] For a better understanding of the present application, a further description will be made below in connection with specific examples, in which the terms used in the examples are used to describe specific embodiments and do not constitute a limitation on the scope of protection of the present application.

[0037] In the detailed description, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are commercially available unless otherwise specified.

[0038] Unless otherwise specified, the percentages, % and the like in the detailed description are mass percentages.

[0039] In the following examples, T03 and 7633 refer to the model numbers of polypropylenes; wherein T03 is a homopolymer polypropylene; and 7633 is a block copolymer polypropylene.

[0040] In the following examples, 245 refers to the model number of a semi-hindered phenolic antioxidant.

[0041] In the following examples, 300 refers to the model number of a sulfur-based antioxidant.

[0042] In the following examples, 1024 refers to the model number of a copper resistance antioxidant.

[0043] In the following examples, NAB-82 and RB-510 refer to the model numbers of nucleating agents, also known as No. 82 in β nucleating agents (β-NA).

[0044] In the following examples, 500N refers to the model number of white mineral oil.

[0045] Example 1 Preparation of polypropylene insulation material, comprising the following steps:

[0046] S1: The following raw materials are weighed according to the mass percentage:

[0047] Polypropylene T03 93.7%

[0048] Concentrated masterbatch 6.3%

[0049] The concentrated masterbatch contains the following ingredients:

[0050]

[0051]

[0052] S2: mix the polypropylene in the concentrated masterbatch with white mineral oil uniformly for use, to obtain granules;

[0053] S3: premix the antioxidant and nucleating agent into powder;

[0054] S4: mix the granules and powder uniformly, and then add them into a double-screw extruder for extrusion granulation; the extrusion temperature is controlled between 190-210°C during the extrusion granulation, and the main motor speed of the extruder is 300-500 rpm / min.

[0055] to obtain the concentrated masterbatch;

[0056] S5: mix the concentrated masterbatch with the remaining polypropylene uniformly, and then add them into a double-screw extruder for extrusion granulation; the extrusion temperature is controlled between 190-210°C during the extrusion granulation, and the main motor speed of the extruder is 300-500 rpm / min, to obtain the polypropylene insulation material.

[0057] Preparation of the polypropylene insulation material in Example 2 includes the following steps:

[0058] S1: weigh the following raw materials according to the mass percentage:

[0059] Polypropylene T03 93.7%

[0060] Concentrated masterbatch 6.3%

[0061] The concentrated masterbatch contains the following components:

[0062]

[0063] S2: mix the polypropylene in the concentrated masterbatch with white mineral oil uniformly for use, to obtain granules;

[0064] S3: premix the antioxidant and nucleating agent into powder;

[0065] S4: mix the granules and powder uniformly, and then add them into a double-screw extruder for extrusion granulation; the extrusion temperature is controlled between 190-210°C during the extrusion granulation, and the main motor speed of the extruder is 300-500 rpm / min.

[0066] to obtain the concentrated masterbatch;

[0067] S5: mix the concentrated masterbatch with the remaining polypropylene uniformly, and then add them into a double-screw extruder for extrusion granulation; the extrusion temperature is controlled between 190-210°C during the extrusion granulation, and the main motor speed of the extruder is 300-500 rpm / min, to obtain the polypropylene insulation material.

[0068] Preparation of the polypropylene insulation material in Example 3 includes the following steps:

[0069] S1: Take the following raw materials by mass percentage:

[0070] Polypropylene T03 92.7%

[0071] Concentrated master batch 7.3%

[0072] The concentrated master batch contains the following ingredients:

[0073]

[0074] S2: Mix the polypropylene in the concentrated master batch with white mineral oil uniformly for use, obtaining granules;

[0075] S3: Premix the antioxidant and nucleating agent into powder;

[0076] S4: Mix the granules and powder uniformly, then add them into a double-screw extruder for extrusion granulation. The extrusion temperature is controlled between 190-210°C during extrusion granulation, and the main motor speed of the extruder is 300-500 rpm / min.

[0077] Concentrated master batch is obtained;

[0078] S5: Mix the concentrated master batch with the remaining part of polypropylene uniformly, then add them into a double-screw extruder for extrusion granulation. The extrusion temperature is controlled between 190-210°C during extrusion granulation, and the main motor speed of the extruder is 300-500 rpm / min, obtaining polypropylene insulation material.

[0079] Example 4: Preparation of polypropylene insulation material, including the following steps:

[0080] S1: Take the following raw materials by mass percentage:

[0081] Polypropylene T03 80%

[0082] Concentrated master batch 20%

[0083] The concentrated master batch contains the following ingredients:

[0084]

[0085] Nucleating agent NAB-82 0.4%

[0086] White mineral oil 500N 0.2%

[0087] S2: Mix the polypropylene in the concentrated master batch with white mineral oil uniformly for use, obtaining granules;

[0088] S3: Premix the antioxidant and nucleating agent into powder;

[0089] S4: The granules and the powder are mixed uniformly, and then are added into a twin-screw extruder for extrusion granulation. The extrusion temperature is controlled between 190-210°C, and the main motor speed of the extruder is 300-500 rpm / min.

[0090] The concentrated master batch is obtained.

[0091] S5: The concentrated master batch and the remaining part of the polypropylene are mixed uniformly, and then are added into a twin-screw extruder for extrusion granulation. The extrusion temperature is controlled between 190-210°C, and the main motor speed of the extruder is 300-500 rpm / min. The polypropylene insulation material is obtained.

[0092] Example 5: Preparation of the polypropylene insulation material, comprising the following steps:

[0093] S1: The following raw materials are weighed according to the mass percentage:

[0094] Polypropylene T03 95%

[0095] Concentrated master batch 5%

[0096] The concentrated master batch contains the following components:

[0097] Polypropylene T03 3.35%

[0098] Antioxidant 245 0.125%

[0099] Antioxidant 300 0.125%

[0100] Antioxidant 1024 0.2%

[0101] Nucleating agent NAB-82 1.25%

[0102] White mineral oil 500N 0.2%

[0103] S2: The polypropylene in the concentrated master batch is mixed uniformly with the white mineral oil for standby, and the granules are obtained.

[0104] S3: The antioxidant and the nucleating agent are premixed into a powder.

[0105] S4: The granules and the powder are mixed uniformly, and then are added into a twin-screw extruder for extrusion granulation. The extrusion temperature is controlled between 190-210°C, and the main motor speed of the extruder is 300-500 rpm / min.

[0106] The concentrated master batch is obtained.

[0107] S5: mix the concentrated masterbatch with the rest of the polypropylene, then add into the twin-screw extruder for extrusion granulation, the extrusion temperature is controlled between 190-210°C, the main motor speed of the extruder is 300-500rpm / min, and polypropylene insulation material is obtained.

[0108] Preparation of polypropylene insulation material of Comparative Example 1, including the following steps:

[0109] S1: weigh the following raw materials according to the mass percentage:

[0110] Polypropylene 7633 93.7%

[0111] Concentrated masterbatch 6.3%

[0112] The concentrated masterbatch contains the following ingredients:

[0113]

[0114] S2: mix the polypropylene in the concentrated masterbatch with white mineral oil uniformly for standby, and granules are obtained;

[0115] S3: mix the antioxidant and nucleating agent into powder;

[0116] S4: mix the granules and powder uniformly, then add into the twin-screw extruder for extrusion granulation, the extrusion temperature is controlled between 190-210°C, and the main motor speed of the extruder is 300-500rpm / min.

[0117] Concentrated masterbatch is obtained;

[0118] S5: mix the concentrated masterbatch with the rest of the polypropylene, then add into the twin-screw extruder for extrusion granulation, the extrusion temperature is controlled between 190-210°C, the main motor speed of the extruder is 300-500rpm / min, and polypropylene insulation material is obtained.

[0119] Preparation of polypropylene insulation material of Comparative Example 2, including the following steps:

[0120] S1: weigh the following raw materials according to the mass percentage:

[0121] Polypropylene 7633 94.2%

[0122] Concentrated masterbatch 5.8%

[0123] The concentrated masterbatch contains the following ingredients:

[0124]

[0125] S2: mix the polypropylene in the concentrated masterbatch with white mineral oil uniformly for standby, and granules are obtained;

[0126] S3: antioxidant premixing into powder;

[0127] S4: mixing the granules and powder uniformly, and then adding into a twin-screw extruder for extrusion granulation, the extrusion temperature being controlled between 190-210°C, and the main motor speed of the extruder being 300-500 rpm / min.

[0128] concentrated master batch is obtained;

[0129] S5: mixing the concentrated master batch with the remaining portion of polypropylene uniformly, and then adding into a twin-screw extruder for extrusion granulation, the extrusion temperature being controlled between 190-210°C, and the main motor speed of the extruder being 300-500 rpm / min, to obtain polypropylene insulation material.

[0130] The polypropylene insulation material prepared in the foregoing Examples 1, 2, 3, 4, 5 and Comparative Examples 1, 2 is subjected to performance testing, specifically:

[0131] 1) tensile strength and elongation at break test: performed according to GB / T 1040.1 and GB / T 1040.3, with a tensile speed of 50 mm / min;

[0132] 2) dielectric transmission and dielectric loss test: performed according to GB / T 1409, with a sample thickness of 1.5 mm and a test frequency of 1 MHz;

[0133] 3) 150°C / 240h short-term heat aging test: the rubber compound is made into RG174 specification wire according to requirements, and the 150°C / 240h short-term heat aging test is performed according to the requirements of ISO19642 standard.

[0134] The results are shown in Table 1 below.

[0135] Table 1: polypropylene insulation material

[0136]

[0137] From the data in Table 1, it can be seen that the strength of Examples 1-5 is obviously improved compared with Comparative Example 1, mainly because the tensile strength of homopolymer PP is higher than that of block copolymer PP;

[0138] Comparative Example 1 has slightly higher strength than Comparative Example 2, indicating that the addition of nucleating agent can improve the crystal structure of PP;

[0139] The dielectric loss of homopolymer PP at room temperature and high temperature is obviously improved compared with copolymer PP, as shown in Example 1 compared with Comparative Example 1;

[0140] The addition of nucleating agent can improve the dielectric loss performance of the material, as shown in Comparative Example 1 compared with Comparative Example 2;

[0141] Examples 1-5 show that different nucleating agents have different effects and that the optimum amount of addition should be <1.5%.

[0142] The above detailed description is a specific description of one of the possible embodiments of the present application, which is not intended to limit the patent scope of the present application, and any equivalent implementation or change that does not deviate from the present application shall be included in the scope of the technical solutions of the present application.

Claims

1. A high-temperature, low-attenuation polypropylene insulation material, characterized in that: By mass parts contain the following components: Polypropylene 80-95 Concentrated master batch 5-20 The concentrated master batch consists of the following components:

2. The high temperature and low attenuation polypropylene insulation material according to claim 1, characterized in that: The antioxidant is at least one of the semi-hindered phenolic antioxidant, sulfur antioxidant, copper resistance antioxidant.

3. The high temperature low loss polypropylene insulating compound of claim 2, wherein, The antioxidant consists of the following components Semi-hindered phenolic antioxidant 2-2.5 Sulfur antioxidant 2-2.5 Copper resistance antioxidant 1.5-2.

4. The high temperature low loss polypropylene insulating compound of claim 1, wherein, The polypropylene is homopolymer polypropylene.

5. The process for the preparation of high temperature low loss polypropylene insulating material according to any one of claims 1 to 4, characterized in that, Including the following steps: S1: the polypropylene in the concentrated master batch is mixed with white mineral oil uniformly for use, and granules are obtained; S2: the antioxidant, nucleating agent are premixed into powder; S3: the granules and powder are mixed uniformly, and then extruded and granulated; the concentrated master batch is obtained; S4: the concentrated master batch is mixed with the remaining polypropylene, and then extruded and granulated again; the high-temperature low-decay polypropylene insulation material is obtained.

6. The process for the preparation of high temperature low loss polypropylene insulating compound as claimed in claim 5, wherein, In the step S3, the extrusion temperature is controlled between 190-210℃ during extrusion and granulation, and the main machine speed of the extruder is 300-500rpm / min.

7. The process for the preparation of high temperature low loss polypropylene insulating compound as claimed in claim 5, wherein, In the step S4, the extrusion temperature is controlled between 190-210℃ during extrusion and granulation, and the main machine speed of the extruder is 300-500rpm / min.

Images