CN114702747B

CN114702747B - High-temperature-resistant high-oxygen-aging polyolefin material and preparation method and application thereof

Info

Publication number: CN114702747B
Application number: CN202210253642.7A
Authority: CN
Inventors: 王道娟; 陈平绪; 叶南飚; 刘乐文; 付晓; 李计彪
Original assignee: Kingfa Science and Technology Co Ltd
Current assignee: Kingfa Science and Technology Co Ltd
Priority date: 2022-03-15
Filing date: 2022-03-15
Publication date: 2023-09-26
Anticipated expiration: 2042-03-15
Also published as: CN114702747A

Abstract

The invention provides a high-temperature-resistant thermo-oxidative aging-resistant polyolefin material, and a preparation method and application thereof. The polyolefin material comprises the following components in parts by weight: 15-20 parts of LLDPE; 25-30 parts of EBA; 5-10 parts of POE; 40-50 parts of halogen-free flame retardant; 0.1 to 1 part of hindered phenol main antioxidant; 0.1 to 0.3 part of auxiliary antioxidant; 0-8 parts of other auxiliary agents; wherein the average particle size of the hindered phenol main antioxidant and the auxiliary antioxidant is independently 3-10 mu m, and the minimum value of the particle size of the hindered phenol main antioxidant is larger than the maximum value of the particle size of the auxiliary antioxidant. The invention can obviously improve the ageing resistance of the polyolefin material at high temperature through a large number of screening of the antioxidant combinations. Wherein, the prepared polyolefin material still has good flame retardant property after being subjected to thermal oxidative aging treatment at 180 ℃ for 168 hours; the retention rate of tensile strength is above 80 percent and can reach 85 percent; the elongation at break is above 80% and can reach 86%.

Description

High-temperature-resistant high-oxygen-aging polyolefin material and preparation method and application thereof

Technical Field

The invention belongs to the technical field of engineering plastics, and particularly relates to a high-temperature-resistant high-oxygen aging polyolefin material, and a preparation method and application thereof.

Background

With the development of electronic information technology, the development of the wire and cable industry is driven. Cables are used to protect metal circuits therein, often in harsh environmental conditions, such as high and low temperatures, intense ultraviolet radiation, high ozone concentrations, chemical corrosion, and the like. Under severe environment, the cable protection material is easy to age and become brittle and even be decomposed, so that the cable material is exposed, and serious disasters such as short circuit and fire disaster are easy to occur.

Polyolefin is a common cable protective sleeve material, and the flame retardant property and ageing property of the polyolefin can be improved by modifying a matrix or adding functional auxiliary agents such as a flame retardant, an antioxidant, a light stabilizer and the like into the matrix, but the temperature of the cable protective material can reach 100 ℃ or higher under the irradiation of high-strength sunlight due to the severe outdoor environment, so that the heat-resistant and oxygen-ageing-resistant property of the polyolefin material at high temperature is needed to be improved, and the service life of the material at high temperature is prolonged. Patent CN113621187A improves the insulation property and the thermal oxidative aging property of polyethylene by the mutual matching of a sulfur-containing auxiliary agent and a peroxide crosslinking agent, and can resist the high temperature of 135 ℃. However, some cable materials are used at temperatures up to 150 ℃ and even 180 ℃, so that the improvement of the high temperature thermo-oxidative aging resistance (especially the higher temperature resistance) is still a difficulty in the industry.

Accordingly, there is a need to develop a polyolefin cable protective material that can be used for a long period of time in more severe environments.

Disclosure of Invention

The object of the present invention is to provide a high temperature thermo-oxidative ageing resistant polyolefin material which can be used at higher temperatures (> 150 ℃).

It is another object of the present invention to provide a method for preparing the high temperature heat and oxygen aging resistant polyolefin material.

It is another object of the present invention to provide the use of said polyolefin material resistant to high temperature thermal oxidative aging for the preparation of cable protection materials.

In order to achieve the above purpose, the invention adopts the following technical scheme:

the high-temperature-resistant thermo-oxidative aging polyolefin material comprises the following components in parts by weight:

wherein the average particle size of the hindered phenol main antioxidant and the auxiliary antioxidant is independently 3-10 mu m, and the minimum value of the particle size of the hindered phenol main antioxidant is larger than the maximum value of the particle size of the auxiliary antioxidant.

The antioxidant is added into the resin matrix to improve the antioxidant performance of the material, but the aging speed of the material obtained by the conventional antioxidant combination at high temperature (especially at the high temperature of more than 150 ℃) is accelerated, and the service life is shortened.

The inventors of the present invention creatively found, through a large number of screening of antioxidant combinations: in the conventional antioxidant combination, if the particle size of the antioxidant is screened, the aging performance of the prepared material at high temperature (> 150 ℃) is improved; based on the above, further researches show that in a specific particle size range, a specific type of main antioxidant is selected, and the particle size of the main antioxidant is controlled to be larger than that of the auxiliary antioxidant, so that the oxidation resistance of the prepared material at high temperature is obviously improved, and the long-term use of the material at high temperature can be met.

In addition, the inventor also found that if ethylene-butyl acrylate copolymer (EBA) with larger polarity is added into a matrix, the mechanical property (such as tensile property) of the material can be improved under the condition that no compatilizer is added; and the EBA with larger polarity also has a certain adsorption effect on the antioxidant, and because the particle sizes of the antioxidants are different, the adsorption effect of the EBA on the antioxidants with different particle sizes is also different, so that the main antioxidant and the auxiliary antioxidant can form an antioxidant network structure with a specific distribution sequence in the matrix, and the specific antioxidant distribution can obviously improve the ageing performance of the material at high temperature.

The term "high-temperature thermal oxidative aging resistance" (or "thermal oxidative aging resistance") as used herein refers to the retention of mechanical properties of a material after long-term aging compared to the initial mechanical properties before aging.

The particle size of the antioxidant is particularly described, and since the particle size of the antioxidant is small enough, the antioxidant raw material does not change significantly during processing, and therefore, the particle size of the antioxidant is not only the particle size of the raw material, but also the particle size of the antioxidant in the product. In the invention, the particle size of the antioxidant can be controlled in a grinding mode, and the particle size is tested by an electron microscope.

Preferably, the hindered phenol antioxidant is one or a combination of more of an antioxidant 1010 or an antioxidant AO 330; further preferred is the antioxidant AO330.

Optionally, the auxiliary antioxidant is one or a combination of more of phosphite antioxidants or thioester antioxidants.

Preferably, the Linear Low Density Polyethylene (LLDPE) has a melt index of 1 to 3.5g/10min at 190℃under 2.16 kg.

Preferably, the ethylene-butyl acrylate copolymer (EBA) has a melt index of 5 to 10g/10min at 190 ℃ under 2.16 kg.

Preferably, the polyolefin elastomer (POE) has a melt index of 1 to 5g/10min at 190℃and 2.16 kg.

In the invention, LLDPE, EBA and POE are used as composite matrix resins, and the melt index of each resin is detected according to the ISO 1133-1:2011 standard method.

The melt index of the matrix resin is an important index for measuring the melt fluidity, and the melt indexes of the three resins are in the range, so that the composite resin matrix which is uniformly mixed and has no phase separation can be prepared, and the processing performance is good.

Optionally, the polyolefin elastomer is one or a combination of two of an ethylene-butene copolymer or an ethylene-octene copolymer.

Optionally, the halogen-free flame retardant includes, but is not limited to, one or a combination of several of aluminum hydroxide or magnesium hydroxide.

In the present invention, other additives may also be added, including but not limited to one or a combination of several of lubricants or mold release agents, depending on the processing requirements.

Optionally, the lubricant is one or a combination of pentaerythritol stearate, distearamide type lubricant, or PE wax.

Optionally, the release agent includes, but is not limited to, one or a combination of several of erucamide or oleamide.

The preparation method of the high-temperature-resistant thermo-oxidative aging polyolefin material comprises the following steps:

the flame retardant is prepared by uniformly mixing linear low density polyethylene, ethylene-vinyl acetate copolymer, polyolefin elastomer, halogen-free flame retardant, compatilizer, hindered phenol main antioxidant AO330, auxiliary antioxidant and other additives in proportion, extruding at 180-200 ℃ and granulating.

Preferably, the mixing is performed in a high speed mixer.

Preferably, the extrusion is performed in a twin screw extruder.

Preferably, in the double-screw extruder, the plasticizing section temperature is 180-200 ℃ and the die head temperature is 180-200 ℃.

Preferably, the rotation speed of the double screw extruder is 350-450 rpm.

The high-temperature-resistant high-oxygen-aging-resistant polyolefin material is used for preparing cables the use of protective materials is also within the scope of the present invention.

Compared with the prior art, the invention has the beneficial effects that:

according to the invention, through a large number of screening of antioxidant combinations, a specific type of main antioxidant is selected in a specific particle size range, and the particle size of the main antioxidant is controlled to be larger than that of the auxiliary antioxidant, so that the oxidation resistance of the prepared material at high temperature is obviously improved, and the long-term use of the material at high temperature can be satisfied. Wherein, the prepared polyolefin material still has good flame retardant property after being subjected to thermal oxidative aging treatment at 180 ℃ for 168 hours; the retention rate of the tensile strength is above 80%, and the long-term use at high temperature can be satisfied, which can reach 85%; the elongation at break is above 80% and can reach 86%.

Detailed Description

The present invention is further illustrated below with reference to specific examples, which are not intended to limit the invention in any way. Unless specifically stated otherwise, the reagents, methods and apparatus employed in the present invention are those conventional in the art. The reagents and materials used in the present invention are commercially available unless otherwise specified.

The embodiment of the invention adopts the following raw materials:

linear low density polyethylene:

LLDPE-1: ENABLE 2010PA, available from Exxon Mobil, having a melt index of 1g/10min at 190℃and 2.16 kg;

LLDPE-2: EXCEED 3518PA, available from Exxon Mobil at 190℃and 2.16kg with a melt index of 3.5g/10 min;

ethylene-butyl acrylate copolymer:

EBA-1: EBA 1400, melt index 6g/10min at 190℃and 2.16kg, purchased from Akema France;

EBA-2: EBA 3107, a melt index of 10g/10min at 190℃and 2.16kg, available from DuPont, U.S.A.;

polyolefin elastomer:

POE-1: ethylene-octene copolymer, SOLUMER 891, melt index 1g/10min at 190℃and 2.16kg, available from Korea SK chemistry;

POE-2: ethylene-octene copolymer, POE 58750, melt index 0.5g/10min at 190℃and 2.16kg, available from DOW;

POE-3: ethylene-butene copolymer, ENGAGE 8200, melt index 5g/10min at 190℃and 2.16kg, available from DOW;

halogen-free flame retardant:

magnesium hydroxide: aitemag 10FD, available from Jiangsu Ai Teke flame retardant materials Co., ltd;

hindered phenols primary antioxidant:

1# -antioxidant 1010: grinding to a particle size of 7-9 mu m (average particle size of 8 mu m), and purchasing from Yingkou wind-solar chemical industry Co., ltd;

2# -antioxidant 1010: grinding to a particle size of 5-7 mu m (average particle size of 6 mu m), and purchasing from Yingkou wind-solar chemical industry Co., ltd;

3# -antioxidant AO330: grinding to a particle size of 7-9 μm (average particle size of 8 μm), available from BASF;

4#: antioxidant 1010: grinding to a particle size of 2-4 mu m (average particle size of 3 mu m), and purchasing from Yingkou city wind-solar chemical industry Co., ltd;

5# -antioxidant 1010: grinding to a particle size of 12-16 μm (average particle size of 14 μm), and purchasing from Yingkou wind-solar chemical Co., ltd;

hindered amine antioxidant:

antioxidant CHISORB 519: grinding to a particle size of 5-7 mu m (average particle size of 6 mu m), and purchasing from Taiwan double bond chemical group;

auxiliary antioxidant:

1#: phosphite antioxidant LXR 568, ground to a particle size of 2-4 μm (average particle size of 3 μm), purchased from Craien;

2#: phosphite antioxidant RIANOX 168, ground to a particle size of 2-4 μm (average particle size of 3 μm), available from Tianjin An Long New Material Co., ltd;

3#: phosphite antioxidant RIANOX 168, ground to a particle size of 3-4 μm (average particle size of 3.5 μm), available from Tianjin An Long New Material Co., ltd;

4#: phosphite antioxidant RIANOX 168, ground to a particle size of 7-9 μm (average particle size of 8 μm), available from Tianjin An Long New Material Co., ltd;

5#: phosphite antioxidant weston 618, grinding to a particle size of 1-3 μm (average particle size of 2 μm), purchased from holly;

other auxiliaries:

and (3) a lubricant: pentaerythritol stearate, commercially available;

and (3) a release agent: erucamide, commercially available.

Unless otherwise specified, both the parallel examples and comparative examples of the present invention are commercially available products in which one component (e.g., lubricant, mold release agent) is the same.

Examples 1 to 14

The present example provides a series of high temperature thermal oxidative aging resistant polyolefin materials prepared according to the formulations in tables 1-2 according to a preparation method comprising the steps of:

adding linear low-density polyethylene, ethylene-butyl acrylate copolymer, polyolefin elastomer, halogen-free flame retardant, hindered phenol main antioxidant, auxiliary antioxidant and other auxiliary agents into a high-speed mixer according to the proportion shown in tables 1-2, mixing for 5min, wherein the rotating speed of the high-speed mixer is 2000-3000 rpm, and uniformly mixing to obtain a mixture; then added to a twin-screw extruder (screw aspect ratio L/d=48:1), the temperature of the double screw extruder from the feeding section to ten sections of the machine head is 180 ℃,190 ℃ and the like in turn at 180-200℃ the melt extrusion and granulation are carried out at 190 ℃, 200 ℃ and 350-450 rpm.

Table 1 the contents (parts by weight) of the respective components in the high temperature heat and oxygen aging resistant polyolefin materials of examples 1 to 6

Table 2 the contents (parts by weight) of the respective components in the high temperature heat and oxygen aging resistant polyolefin materials of examples 7 to 14

Comparative example 1

This comparative example produces a polyolefin material that differs from example 3 in that the secondary antioxidant is replaced with a # 1 antioxidant 1010.

Comparative example 2

This comparative example produces a polyolefin material that differs from example 3 in that the # 1 antioxidant 1010 is replaced with a # 1 secondary antioxidant.

Comparative example 3

This comparative example produces a polyolefin material that differs from example 3 in that the # 1 secondary antioxidant is replaced with a smaller particle size # 5 secondary antioxidant.

Comparative example 4

This comparative example produces a polyolefin material that differs from example 3 in that the primary antioxidant # 1 is replaced with a primary antioxidant # 5 having a larger particle size.

Comparative example 5

This comparative example produces a polyolefin material that differs from example 3 in that the primary hindered phenol antioxidant # 1 is replaced with the hindered amine antioxidant CHISORB 519.

Comparative example 6

This comparative example produces a polyolefin material that differs from example 3 in that the # 1 secondary antioxidant is replaced with a # 4 secondary antioxidant having the same particle size as the primary antioxidant.

Comparative example 7

This comparative example produces a polyolefin material that differs from example 3 in that the primary antioxidant # 1 is replaced with a primary antioxidant # 4 having the same particle size as the secondary antioxidant.

Comparative example 8

This comparative example produces a polyolefin material that differs from example 3 in that the primary antioxidant # 1 is replaced with a primary antioxidant # 4, while the secondary antioxidant # 1 is replaced with a secondary antioxidant # 4 (i.e., the secondary antioxidant has a particle size greater than the primary antioxidant).

Comparative example 9

This comparative example was made of a polyolefin material, differing from example 3 in that EBA was replaced with EVA (7350M, available from taiwan platform).

Performance testing

The properties of the polyolefin materials prepared in the above examples and comparative examples were tested, and the test items and test methods are as follows:

1. tensile strength and elongation at break: preparing dumbbell-shaped bars from the polyolefin materials prepared in the examples and the comparative examples, and measuring according to a measuring method of GB/T1040.3-2006, wherein the measuring temperature is 25 ℃, and the stretching rate is 250mm/min;

2. high temperature thermo-oxidative aging resistance: the method is measured according to GB/T2951.12-2008, specifically, polyolefin materials prepared in examples and comparative examples are prepared into dumbbell-shaped bars, the dumbbell-shaped bars are placed into a thermal oxidation aging box, treated for 168 hours under the condition of 180 ℃ and 100-200 times/h of ventilation times, and the tensile strength and the elongation at break of the treated bars are tested;

the test results are shown in Table 3.

TABLE 3 Performance test results

As can be seen from table 3:

the high-temperature-resistant and high-oxygen aging-resistant polyolefin material prepared in each embodiment of the invention can still have good mechanical properties after being subjected to 180 ℃ thermal oxidation aging treatment for 168 hours; the retention of tensile strength is above 80% and can be as high as 85% (example 3); the retention rate of elongation at break is above 80% and can reach 86% (example 3).

From the results of example 3, examples 7 to 10 and comparative examples 1 to 8, it can be seen that the aging performance of the material at high temperature can be significantly improved by selecting the combination of the primary antioxidant and the secondary antioxidant within the specific particle size range of the present invention. In comparative examples 1 and 2, only the primary antioxidant or the secondary antioxidant is selected, and the obtained material has poor aging performance at high temperature; the antioxidants with smaller particle size and larger particle size are respectively selected in comparative examples 3 and 4, and the aging performance of the obtained material at high Wen Xia is also poor; the primary antioxidant and the secondary antioxidant in comparative examples 6 and 7 have the same particle size, and the primary antioxidant in comparative example 8 has a particle size smaller than that of the secondary antioxidant, so that the high-temperature aging resistance of the material cannot be improved; other ethylene copolymers were selected in the matrix of comparative example 9, and the initial mechanical properties of the obtained material were poor, and the aging phenomenon of the material at high temperature was also serious.

The results of example 3 and examples 11 to 14 show that the mechanical properties and the high-temperature thermal oxidative aging resistance of the prepared polyolefin material can be remarkably improved by selecting LLDPE, EVA and POE resin matrixes with specific melt fingers.

The results of example 3 and comparative example 5 show that the polyolefin materials with good mechanical properties and high-temperature thermo-oxidative aging resistance can be prepared by selecting the specific hindered phenol antioxidant.

The foregoing description of the embodiments has been provided for the purpose of illustrating the general principles of the invention, and is not meant to limit the scope of the invention, but to limit the invention to the particular embodiments, and any modifications, equivalents, improvements, etc. that fall within the spirit and principles of the invention are intended to be included within the scope of the invention.

Claims

1. The high-temperature-resistant thermo-oxidative aging polyolefin material is characterized by comprising the following components in parts by weight:

wherein the average particle size of the hindered phenol main antioxidant and the auxiliary antioxidant is independently 3-8 mu m, and the minimum value of the particle size of the hindered phenol main antioxidant is larger than the maximum value of the particle size of the auxiliary antioxidant; the hindered phenol main antioxidant is one or a combination of more of an antioxidant 1010 and an antioxidant AO 330; the auxiliary antioxidant is phosphite antioxidant.

2. The high temperature resistant thermo-oxidative aging polyolefin material according to claim 1, wherein the hindered phenol based primary antioxidant is antioxidant AO330.

3. The high temperature thermo-oxidative aging resistant polyolefin material according to claim 1, wherein the linear low density polyethylene has a melt index of 1 to 3.5g/10min at 190 ℃ under 2.16 kg.

4. The high temperature resistant thermo-oxidative aging polyolefin material according to claim 1, wherein the ethylene-butyl acrylate copolymer has a melt index of 5 to 10g/10min at 190 ℃ under 2.16kg conditions.

5. The high temperature thermo-oxidative aging resistant polyolefin material according to claim 1, wherein the polyolefin elastomer has a melt index of 1 to 5g/10min at 190 ℃ under 2.16 kg.

6. The high temperature resistant thermo-oxidative aging polyolefin material according to claim 1, wherein the polyolefin elastomer is one or a combination of two of an ethylene-butene copolymer or an ethylene-octene copolymer.

7. The method for preparing the high-temperature-resistant thermo-oxidative aging-resistant polyolefin material according to claim 1 to 6, comprising the steps of:

the preparation method comprises the steps of uniformly mixing linear low-density polyethylene, ethylene-butyl acrylate copolymer, polyolefin elastomer, halogen-free flame retardant, hindered phenol main antioxidant, auxiliary antioxidant and other additives in proportion, extruding at 180-200 ℃, and granulating.

8. Use of the high temperature resistant thermo-oxidative ageing resistant polyolefin material according to claims 1-6 for the preparation of cable protection materials.