Decrosslinked polyolefin resin, composition comprising the same, and method of preparing the same

Abstract

The decrosslinked polyolefin resin disclosed herein has a tan δ greater than or equal to 0.9 at 0.1 radians / second and a decrosslinking index (DI) greater than or equal to 100. The decrosslinked polyolefin resin of this invention exhibits improved properties such as durability, thermal stability, and chemical resistance.

Description

[Technical Field]

[0001] This invention relates to decrosslinked polyolefin resins, compositions comprising the same, and methods for preparing the same. More particularly, this invention relates to decrosslinked polyolefin resins obtained from the recovery of crosslinked polyolefin resins (having a tan δ greater than or equal to 0.9, low gel fraction, and high elongation), compositions comprising the same, and methods for preparing the same. [Previous Technology]

[0002] Due to their excellent insulation properties and heat / chemical resistance, cross-linked polyolefin resins can be used in cables and the like. Although various plastic recycling schemes have been studied to achieve resource recovery, the effective recycling of most cross-linked polyolefin resins has not yet been achieved. To address this issue, methods for removing the cross-linking structure of polyolefins to decrosslinked polyolefins are needed.

[0003] Decrosslinking processes are typically performed at high extruder temperatures to obtain decrosslinked polyolefin resins in order to maintain a low gel fraction. However, this decrosslinked polyolefin resin may suffer from a significant decrease in molecular weight and deterioration in mechanical properties such as tensile strength and elongation. Furthermore, decrosslinking processes optimized to maintain mechanical properties may lead to problems such as high gel fraction and uneven molecular weight distribution.

[0004] Therefore, there is a need to develop recyclable crosslinked polyolefin resins with low gel fraction, uniform molecular weight distribution and good elongation, resin compositions containing the same, and methods for their preparation.

[0005] The background technology of this invention is disclosed in Korean Patent No. 10-2290806. [Summary of the Invention]

[0006] [The technical problem to be solved]

[0007] One object of the present invention is to provide a decrosslinked polyolefin resin having a tan δ greater than or equal to 0.9, a low gel fraction, and a high elongation, a composition comprising the thereof, and a method thereof for preparation thereof.

[0008] Another object of the present invention is to provide a decrosslinked polyolefin resin with uniform molecular weight distribution and low gel fraction, a composition comprising the same, and a method thereof for preparation thereof.

[0009] Another object of the present invention is to provide a method for preparing decrosslinked polyolefins, which can achieve a uniform decrosslinking reaction.

[0010] The above and other objects of the present invention can be easily understood from the detailed description of the following embodiments.

[0011] [Technical Means]

[0012] 1. An embodiment of the present invention relates to a decrosslinked polyolefin resin. The decrosslinked polyolefin resin has a tan δ greater than or equal to about 0.9 at 0.1 radians / second, and its decrosslinking index (DI) is greater than or equal to 100. Tan δ is defined as Equation 1, and DI is defined as Equation 2:

[0013] tan δ = G'' / G' ---(1)

[0014] Where G” is the loss modulus of the decrosslinked polyolefin resin at 0.1 radians / second, and G' is the storage modulus of the decrosslinked polyolefin resin at 0.1 radians / second, and

[0015] DI = (E×tan δ) / C ---(2)

[0016] where E is the elongation of the decrosslinked polyolefin resin (in %), tan δ is the value calculated according to Equation 1, and C is the gel fraction of the decrosslinked polyolefin resin (in wt%).

[0017] 2. In Example 1, the gel fraction of the decrosslinked polyolefin resin may be less than or equal to about 2 wt%, and the elongation may be greater than or equal to about 100%.

[0018] 3. In Examples 1 and 2, the weight-average molecular weight of the decrosslinked polyolefin resin may be greater than or equal to about 50,000 g / mol.

[0019] 4. In Examples 1 to 3, the decrosslinked polyolefin resin may include the decrosslinked product of peroxide crosslinked polyolefin resin, electron beam crosslinked polyolefin resin, or silane crosslinked polyolefin resin.

[0020] 5. In Examples 1 to 4, the decrosslinked polyolefin resin may conform to Formula 3:

[0021] Approximately 45 ≤ G0' / G' ≤ Approximately 2,000 ---(3)

[0022] where G0' is the storage modulus of the cross-linked polyolefin resin at 0.1 radians / second, and G' is the storage modulus of the decross-linked polyolefin resin at 0.1 radians / second.

[0023] 6. In Examples 1 to 5, the decrosslinked polyolefin resin may conform to Formula 4:

[0024] Approximately 35 ≤ V0 / V ≤ Approximately 3,000 ---(4)

[0025] Where V0 is the complex viscosity of the cross-linked polyolefin resin at 0.1 radians / second, and V is the complex viscosity of the decross-linked polyolefin resin at 0.1 radians / second.

[0026] 7. Another embodiment of the invention relates to a composition. The composition comprises the decrosslinked polyolefin resin described in any one of Examples 1 to 6.

[0027] 8. In Example 8, the composition may further comprise a cross-linked polyolefin resin.

[0028] 9. Another embodiment of the present invention relates to a method for preparing a decrosslinked polyolefin resin. The method includes extruding a crosslinked polyolefin resin using a twin-screw extruder to obtain a decrosslinked polyolefin resin conforming to formula 3:

[0029] Approximately 45 ≤ G0' / G' ≤ Approximately 2,000 ---(3)

[0030] Where G0' is the storage modulus of the cross-linked polyolefin resin at 0.1 radians / second, and G' is the storage modulus of the decross-linked polyolefin resin at 0.1 radians / second.

[0031] 10. In Example 9, the temperature at which the crosslinked polyolefin resin is extruded by twin screws can be greater than or equal to about 230°C and less than about 350°C.

[0032] 11. In Examples 9 and 10, the tan δ of the crosslinked polyolefin resin at 0.1 radians / second can be about 0.1 to about 0.7.

[0033] 12. In Examples 9 to 11, the crosslinked polyolefin resin may include peroxide crosslinked polyolefin resin, electron beam crosslinked polyolefin resin, or silane crosslinked polyolefin resin.

[0034] 13. In Examples 9 to 12, the decrosslinked polyolefin resin may conform to Formula 4:

[0035] Approximately 35 ≤ V0 / V ≤ Approximately 3,000 ---(4)

[0036] Where V0 is the complex viscosity of the cross-linked polyolefin resin at 0.1 radians / second, and V is the complex viscosity of the decross-linked polyolefin resin at 0.1 radians / second.

[0037] 14. In Examples 9 to 13, the tan δ of the decrosslinked polyolefin resin at 0.1 radians / second can be greater than or equal to 0.9, and tan δ is defined as Equation 1:

[0038] tan δ = G'' / G', ---(1)

[0039] where G” is the loss modulus of the decrosslinked polyolefin resin at 0.1 radians / second, and G' is the storage modulus of the decrosslinked polyolefin resin at 0.1 radians / second.

[0040] 15. In Examples 9 to 14, the decrosslinking index (DI) of the decrosslinked polyolefin resin may be greater than or equal to about 100, and DI is defined as Equation 2:

[0041] DI = (E×tan δ) / C ---(2)

[0042] where E is the elongation of the decrosslinked polyolefin resin (in %), tan δ is the value calculated according to Equation 1, and C is the gel fraction of the decrosslinked polyolefin resin (in wt%).

[0043] 16. In Examples 9 to 15, the gel fraction of the decrosslinked polyolefin resin may be less than or equal to about 2 wt%, while the elongation may be greater than or equal to about 100%.

[0044] 17. In Examples 9 to 16, the weight-average molecular weight of the decrosslinked polyolefin resin may be greater than or equal to about 50,000 g / mol.

[0045] [Invention Benefits]

[0046] Embodiments of the present invention provide a decrosslinked polyolefin resin with tan δ greater than or equal to 0.9, low gel fraction, and high elongation, a composition containing the same, and a method for preparing the same.

Implementation Method

[0048] Embodiments of the present invention will be described in detail below. It should be understood that the terms "comprising," "having," and "including" used in the specification indicate the presence of the stated structures, steps, operations, units, and / or components, but do not exclude the presence or addition of one or more other structures, steps, operations, units, and / or components, unless the term "only" is explicitly used for limitation. The singular forms "a," "an," and "the" used herein also include the plural forms, unless otherwise explicitly stated.

[0049] When interpreting components, values ​​related to a particular component will be interpreted as including tolerance ranges, unless otherwise explicitly stated. The term "about" as used herein means within ±5% of the value, unless otherwise explicitly stated.

[0050] The embodiments of the present invention will be described here with reference to the accompanying drawings.

[0051] This invention relates to decrosslinked polyolefin resins, resin compositions containing the same, and methods for preparing the same.

[0052] Generally speaking, crosslinking refers to the bond that connects a polymer chain (which is a polymer containing repeating units linked together) to another polymer chain, while decrosslinking refers to the process of removing or weakening crosslinking bonds.

[0053] The method for preparing the decrosslinked polyolefin resin of the present invention can be a decrosslinking reaction of the crosslinked polyolefin resin. The decrosslinking reaction can be carried out to control the physical properties of the polymer or improve its recyclability.

[0054] The decrosslinked polyolefin resin of the present invention has a tan δ of 0.1 radians / second that is greater than or equal to 0.9, as defined in Formula 1.

[0055] tan δ = G'' / G' ---(1)

[0056] where G” is the loss modulus of the decrosslinked polyolefin resin at 0.1 radians / second, and G' is the storage modulus of the decrosslinked polyolefin resin at 0.1 radians / second.

[0057] When the tan δ of the decrosslinked polyolefin resin at 0.1 radians / second is greater than or equal to about 0.9, the decrosslinked polyolefin resin can have good decrosslinking characteristics, and its physical properties can be similar to those of the polyolefin before crosslinking, thus having good recyclability. In some embodiments, the tan δ of the decrosslinked polyolefin resin at 0.1 radians / second can be greater than or equal to about 0.92, for example, about 0.93 to about 10, specifically about 0.93 to about 5. In some embodiments, the tan δ of the decrosslinked polyolefin resin at 0.1 radians / second can be 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3.0.

[0058] In addition, the decrosslinking index (DI) of the decrosslinked polyolefin resin is greater than or equal to about 100, which is defined by Equation 2.

[0059] DI = (E×tan δ) / C ---(2)

[0060] Where E is the elongation of the decrosslinked polyolefin resin (in %), tan δ is the value calculated according to Equation 1, and C is the gel fraction of the decrosslinked polyolefin resin (in wt%).

[0061] In some embodiments, the decrosslinking index (DI) of the decrosslinked polyolefin resin can be from about 100 to about 3,000, specifically from about 250 to about 2,500, for example from about 400 to about 2,000. Decrosslinked polyolefin resins in this range not only have good decrosslinking properties, but also good mechanical properties.

[0062] The gel fraction of the decrosslinked polyolefin resin may be less than or equal to about 2 wt%, for example less than or equal to about 1.5 wt%, preferably less than or equal to about 1.0 wt%, more preferably less than or equal to about 0.75 wt%, and even more preferably about 0.001 wt% to about 0.5 wt%.

[0063] The elongation of the decrosslinked polyolefin resin can be greater than or equal to 100%, for example, greater than or equal to about 200%, specifically about 300% to about 600%.

[0064] The weight-average molecular weight (Mw) of the decrosslinked polyolefin resin can be greater than or equal to about 50,000 g / mol, preferably about 80,000 g / mol to about 300,000 g / mol. Decrosslinked polyolefin resins in this range can have good mechanical properties.

[0065] The decrosslinked polyolefin resin may be a decrosslinked product of peroxide-crosslinked polyolefin resin, electron beam-crosslinked polyolefin resin, or silane-crosslinked polyolefin resin, preferably a decrosslinked product of peroxide-crosslinked polyolefin resin. However, it should be understood that the types of crosslinked polyolefin resins used are not limited to the examples above. Polyolefin resins may include olefin-based homopolymers such as polyethylene or polypropylene, or olefin-based random or bulk copolymers obtained by polymerizing two or more olefin monomers. Polyolefins may include ultra-low density polyethylene, low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, or combinations thereof. However, it should be understood that the types of polyethylene used are not limited to the examples above.

[0066] In some embodiments, the decrosslinked polyolefin resin may conform to Formula 3.

[0067] Approximately 45 ≤ G0' / G' ≤ Approximately 2,000 ---(3)

[0068] where G0' is the storage modulus of the cross-linked polyolefin resin at 0.1 radians / second, and G' is the storage modulus of the decross-linked polyolefin resin at 0.1 radians / second.

[0069] In some embodiments, G0' / G' can be from about 55 to about 1,900, specifically from about 65 to about 1,800, and more preferably from about 75 to about 1,700. This ratio range allows the decrosslinked polyolefin resin to have good decrosslinking properties.

[0070] In some embodiments, the decrosslinked polyolefin resin may conform to Formula 4.

[0071] Approximately 35 ≤ V0 / V ≤ Approximately 3,000 ---(4)

[0072] Where V0 is the complex viscosity of the cross-linked polyolefin resin at 0.1 radians / second, and V is the complex viscosity of the decross-linked polyolefin resin at 0.1 radians / second.

[0073] In some embodiments, V0 / V may be from about 40 to about 2,000, preferably from about 45 to about 1,000, such as from about 55 to about 950. This range of ratios allows the decrosslinked polyolefin resin to have good decrosslinking properties.

[0074] Another embodiment of the present invention relates to a composition containing the above-described decrosslinked polyolefin resin. In some embodiments, the composition may include a decrosslinked polyolefin resin and a crosslinked polyolefin resin. In this way, the combination of decrosslinked and crosslinked polyolefins can compensate for the reduction in mechanical properties (such as tensile strength and elongation) associated with using decrosslinked polyolefin resin alone, and can further reduce the color or odor intensity of the resin. In some embodiments, relative to 100 parts by weight of decrosslinked polyolefin resin, the composition may include about 0.01 parts by weight to about 80 parts by weight of crosslinked polyolefin.

[0075] Other embodiments of the present invention relate to a method for preparing decrosslinked polyolefin resin. The method includes twin-screw extrusion of crosslinked polyolefin resin to make the decrosslinked polyolefin resin conform to Formula 3.

[0076] Approximately 45 ≤ G0' / G' ≤ Approximately 2,000 ---(3)

[0077] where G0' is the storage modulus of the cross-linked polyolefin resin at 0.1 radians / second, and G' is the storage modulus of the decross-linked polyolefin resin at 0.1 radians / second.

[0078] In some embodiments, G0' / G' can be from about 55 to about 1,900, specifically from about 65 to about 1,800, and more preferably from about 75 to about 1,500. This ratio range allows the decrosslinked polyolefin resin to have good decrosslinking properties.

[0079] The temperature at which the crosslinked polyolefin resin is extruded by a twin-screw extruder can be greater than or equal to about 230°C and less than about 350°C, preferably about 250°C to about 330°C. This temperature range minimizes the reduction in molecular weight and ensures that the decrosslinked polyolefin resin has good mechanical properties and a low gel fraction.

[0080] In some embodiments, the tan δ of the crosslinked polyolefin resin at 0.1 radians / second may be about 0.1 to about 0.7, for example about 0.11 to about 0.6.

[0081] In some embodiments, the crosslinked polyolefin resin may include peroxide crosslinked polyolefin resin, electron beam crosslinked polyolefin resin, or silane crosslinked polyolefin resin, preferably peroxide crosslinked polyolefin resin. However, it should be understood that the types of crosslinked polyolefin resins used are not limited to the examples above.

[0082] For example, polyolefin resins may include olefin-based homopolymers such as polyethylene or polypropylene, or olefin-based random or bulk copolymers obtained by polymerizing two or more olefin monomers. Polyolefins may include ultra-low density polyethylene, low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, or combinations thereof. However, it should be understood that the types of polyethylene used herein are not limited to the examples above.

[0083] The present invention will now be described in detail with reference to some embodiments. However, it should be noted that these embodiments are for illustrative purposes only and are not intended to limit the invention in any way. [Examples]

[0084] Example 1 Cross-linked polyethylene resin (XLPE) was decrosslinked and extruded at 300°C using a twin-screw extruder (Φ: 30 mm, SM Platek Co., Ltd.) at an extrusion rate of 8 kg / hour to prepare decrosslinked polyethylene resin. The storage modulus ratio (G0' / G') before and after decrosslinking was 135.

[0085] Example 2 Decrosslinked polyethylene resin was prepared in the same manner as in Example 1, except that the extrusion temperature for decrosslinking was 280°C, so that the storage modulus ratio (G0' / G') before and after decrosslinking was 49.

[0086] Example 3 Decrosslinked polyethylene resin was prepared in the same manner as in Example 1, except that a screw unit combination different from that in Example 1 was used, and decrosslinking was performed at a temperature of 250°C and an extrusion rate of 4 kg / hour, so that the storage modulus ratio (G0' / G') before and after decrosslinking was 278.

[0087] Example 4 Decrosslinked polyethylene resin was prepared in the same manner as in Example 1, except that the extrusion temperature for decrosslinking was 250°C, so that the storage modulus ratio (G0' / G') before and after decrosslinking was 430.

[0088] Comparative Example 1 uses cross-linked polyethylene resin (XLPE), which has not been decrosslinked and extruded.

[0089] Comparative Example 2: Decrosslinked polyethylene resin was prepared in the same manner as in Example 1, except that the decrosslinking extrusion temperature was 400°C using a single screw extruder, so that the storage modulus ratio (G0' / G') before and after decrosslinking was 2,159,680.

[0090] Comparative Example 3: Decrosslinked polyethylene resin was prepared in the same manner as in Example 1, except that the temperature of the decrosslinking extrusion was 220°C using a twin-screw extruder, so that the storage modulus ratio (G0' / G') before and after decrosslinking was 21.

[0091] Comparative Example 4: Cross-linked polyethylene resin was decrosslinked by extruding at 300°C using a single screw extruder in the presence of supercritical fluid ethanol as a reaction solvent to prepare decrosslinked polyethylene resin.

[0092] The properties of the decrosslinked polyethylene resins prepared in the Examples and Comparative Examples were evaluated, and the results are shown in Table 1.

[0093] (1) Gel fraction (in wt%)

[0094] According to ASTM D2765, the gel fraction was analyzed using xylene. #120 stainless steel mesh was used here. Specifically, the gel content of the prepared decrosslinked polyethylene resin was measured by extraction with xylene at a temperature greater than or equal to 140°C followed by drying, and the gel fraction was confirmed as the percentage of the weight of the insoluble component relative to the weight of the original sample.

[0095] (2) tan δ (loss factor)

[0096] The sample was subjected to frequency scanning test using a rheometer (modular compact rheometer 301 (MCR 301), Anton Paar GmbH) at a temperature of 190°C, a shear strain of 1%, and a frequency of 0.1 radians / second to 500 radians / second.

[0097] A sheet-like sample with a diameter of 25 mm and a thickness of 1 mm was prepared by hot pressing.

[0098] Here, the storage modulus (G') and loss modulus (G”) of the sample are measured at a temperature of 190°C and a frequency of 0.1 radians / second, and tan δ (loss factor) depends on the ratio of G” to G' (G” / G'), which is defined as Equation 1.

[0099] tan δ = G'' / G' ---(1)

[0100] where G” is the loss modulus of the decrosslinked polyolefin resin at 0.1 radians / second, and G' is the storage modulus of the decrosslinked polyolefin resin at 0.1 radians / second.

[0101] In addition, the storage modulus of the samples before and after decrosslinking was measured at a frequency of 0.1 radians / second, and the storage modulus ratio (G0' / G') was calculated according to Equation 3.

[0102] 45 ≤ G0' / G' ≤ 2,000 ---(3)

[0103] where G0' is the storage modulus of the cross-linked polyolefin resin at 0.1 radians / second, and G' is the storage modulus of the decross-linked polyolefin resin at 0.1 radians / second.

[0104] (3) Elongation (in %)

[0105] The elongation of the Type IV specimen was measured at a tensile rate of 50 mm / min in accordance with ASTM D638.

[0106] (4) Decrosslinking index (DI)

[0107] After obtaining tan δ of 0.1 radians / second, the decrosslinking index is calculated according to Equation 2.

[0108] DI = (E×tan δ) / C ---(2)

[0109] Where E is the elongation of the decrosslinked polyolefin resin (in %), and C is the gel fraction of the decrosslinked polyolefin resin (in wt%).

[0110] (5) Complex viscosity (in Pa·s)

[0111] The samples were subjected to frequency scanning tests using a rheometer (modular compact rheometer 301 (MCR 301), Anton Paar GmbH) at a temperature of 190°C, a shear strain of 1%, and a frequency of 0.1 radians / second to 500 radians / second.

[0112] Here, the complex viscosity of the sample before and after decrosslinking is measured, and then the complex viscosity ratio is obtained according to Equation 4.

[0113] 35 ≤ V0 / V ≤ 3,000 ---(4)

[0114] Where V0 is the complex viscosity of the cross-linked polyolefin resin at 0.1 radians / second, and V is the complex viscosity of the decross-linked polyolefin resin at 0.1 radians / second.

[0115] Table 1 Gel fraction (wt%) tan δ Elongation (%) Decrosslinking index (DI) G0' / G' V0 / V Example 1 0.3 1.3 310 1343.3 135 83 Example 2 0.6 0.93 450 697.5 49 36 Example 3 0.2 2.01 1,012 10170.6 278 125 Example 4 1.1 1.02 176 160 430 303 Comparative Example 1 >80 0.12 112 < 0.2 1 1 Comparative Example 2 0.2 4.32 3 64.8 2,159,680 490,471 Comparative Example 3 1.7 0.66 120 46.6 twenty one 17 Comparative Example 4 2.5 0.8 390 124.8 - -

[0116] As shown in Table 1, the decrosslinked polyolefin resins prepared in Examples 1 to 3 exhibit high elongation, significantly low gel fraction, and good decrosslinking properties. Conversely, the gel fraction of the crosslinked polyolefin resin prepared in Comparative Example 1 and the decrosslinked polyolefin resins prepared in Comparative Examples 3 and 4 is higher than that of the decrosslinked polyolefin resins prepared in the examples. Although the decrosslinked polyolefin resin prepared in Example 2 has a low gel fraction, its elongation is significantly lower.

[0117] Figure 1 shows a comparison of the frequency-related composite viscosity profiles of Example 1, Comparative Example 1, and Comparative Example 3. The composite viscosity profiles were measured here to evaluate the properties of the corresponding polymers, such as their physical state, degree of crosslinking, and processability.

[0118] As shown in Figure 1, it can be seen that the degree of crosslinking of the decrosslinked polyolefin resin prepared in Example 1 is lower than that of the crosslinked polyolefin resin prepared in Comparative Example 1 and the decrosslinked polyolefin resin prepared in Comparative Example 3. Therefore, the decrosslinked polyolefin resin prepared in Example 1 has a lower complex viscosity. In addition, the calculated results of the complex viscosity ratio (V0 / V) before and after decrosslinking show that the complex viscosity ratio of the decrosslinked polyolefin resin prepared in Example 1 is higher than that of the decrosslinked polyolefin resin prepared in Comparative Example 3.

[0119] Figure 2 shows a comparison of the profiles of the frequency-dependent storage modulus (G') and loss modulus (G”) in Example 1, Comparative Example 1, and Comparative Example 3. Here, G' > G” at low frequencies such as 0.1 radians / second indicates that crosslinking has occurred.

[0120] As shown in Figure 2, compared to the crosslinked polyolefin resin prepared in Comparative Example 1 and the decrosslinked polyolefin resin prepared in Comparative Example 3, the decrosslinked polyolefin resin prepared in Example 1 exhibits different rheological properties. The decrosslinked polyolefin resin prepared in Comparative Example 3 is a decrosslinked product with a high gel fraction, and its tan δ at 0.1 radians / second is less than 0.9. Conversely, the decrosslinked polyolefin resin prepared in Example 1 has a tan δ greater than or equal to 0.9, while G' and G” are approximately the same. Furthermore, the decrosslinked polyolefin resin prepared in Comparative Example 3 has a tan δ of only 0.66, despite having a low gel fraction such as 1.7 wt%. Thus, for decrosslinked products with similar gel fractions, the degree of decrosslinking can be more accurately determined by the measurement results of rheological properties such as tan δ.

[0121] It should be understood that those skilled in the art can make various adjustments, changes, modifications and equivalent embodiments without departing from the spirit and scope of the embodiments of the present invention. [Simplified Explanation of the Diagram]

[0047] Figure 1 shows a comparison of the profiles of the frequency-dependent composite viscosity of Example 1, Comparative Example 1, and Comparative Example 3. Figure 2 shows a comparison of the profiles of the frequency-dependent storage modulus (G') and loss modulus (G”) of Example 1, Comparative Example 1, and Comparative Example 3.

Claims

1. A decrosslinked polyolefin resin, wherein the tan δ at 0.1 radians / second is greater than or equal to 0.9, and the decrosslinking index (DI) is greater than or equal to 100, wherein tan δ is defined as Equation 1, and DI is defined as Equation 2: tan δ = G'' / G' --- (1) where G' is the loss modulus of the decrosslinked polyolefin resin at 0.1 radians / second, and G' is the storage modulus of the decrosslinked polyolefin resin at 0.1 radians / second, and DI = (E×tan δ) / C --- (2) where E is the elongation of the decrosslinked polyolefin resin (in %), tan δ is the value calculated according to Equation 1, and C is the gel fraction of the decrosslinked polyolefin resin (in wt%), wherein the gel fraction of the decrosslinked polyolefin resin is less than or equal to 2 wt%, and the elongation is greater than or equal to 100%.

2. The decrosslinked polyolefin resin as claimed in claim 1, wherein the weight-average molecular weight of the decrosslinked polyolefin resin is greater than or equal to 50,000 g / mol.

3. The decrosslinked polyolefin resin as claimed in claim 1, wherein the decrosslinked polyolefin resin comprises a decrosslinked product of a peroxide-crosslinked polyolefin resin, an electron beam-crosslinked polyolefin resin, or a silane-crosslinked polyolefin resin.

4. The decrosslinked polyolefin resin as claimed in claim 3, wherein the decrosslinked polyolefin resin conforms to formula 3: 45 ≤ G0' / G' ≤ 2,000 --- (3) where G0' is the storage modulus of the crosslinked polyolefin resin at 0.1 radians / second, and G' is the storage modulus of the decrosslinked polyolefin resin at 0.1 radians / second.

5. The decrosslinked polyolefin resin as claimed in claim 3, wherein the decrosslinked polyolefin resin conforms to formula 4: 35 ≤ V0 / V ≤ 3,000 --- (4) where V0 is the complex viscosity of the crosslinked polyolefin resin at 0.1 radians / second, and V is the complex viscosity of the decrosslinked polyolefin resin at 0.1 radians / second.

6. A composition comprising: The decrosslinked polyolefin resin as described in any one of claims 1 to 5; And a cross-linked polyolefin resin.

7. A method for preparing a decrosslinked polyolefin resin, comprising: A cross-linked polyolefin resin is subjected to twin-screw extrusion to obtain a decross-linked polyolefin resin, which conforms to formula 3: 45 ≤ G0' / G' ≤ 2,000 --- (3) where G0' is the storage modulus of the cross-linked polyolefin resin at 0.1 radians / second, and G' is the storage modulus of the decross-linked polyolefin resin at 0.1 radians / second, wherein the temperature of the cross-linked polyolefin resin being subjected to twin-screw extrusion is greater than or equal to 230°C and less than 350°C.

8. A method for preparing a decrosslinked polyolefin resin as described in claim 7, wherein the crosslinked polyolefin resin has a tan δ of 0.1 to 0.7 at 0.1 radians / second.

9. A method for preparing a decrosslinked polyolefin resin as described in claim 7, wherein the decrosslinked polyolefin resin conforms to formula 4: 35 ≤ V0 / V ≤ 3,000 --- (4) where V0 is the complex viscosity of the crosslinked polyolefin resin at 0.1 radians / second, and V is the complex viscosity of the decrosslinked polyolefin resin at 0.1 radians / second.

10. A method for preparing a decrosslinked polyolefin resin as claimed in claim 7, wherein the decrosslinked polyolefin resin has a tan δ greater than or equal to 0.9 at 0.1 radians / second, and tan δ is defined as Equation 1: tan δ = G'' / G', ---(1) where G' is the loss modulus of the decrosslinked polyolefin resin at 0.1 radians / second, and G' is the storage modulus of the decrosslinked polyolefin resin at 0.1 radians / second.

11. The method for preparing the decrosslinked polyolefin resin as described in claim 7, wherein the decrosslinking index (DI) of the decrosslinked polyolefin resin is greater than or equal to 100, and DI is defined as Equation 2: DI = (E×tan δ) / C --- (2) where E is the elongation of the decrosslinked polyolefin resin (in %), tan δ is the value calculated according to Equation 1, and C is the gel fraction of the decrosslinked polyolefin resin (in wt%).

12. The method for preparing the decrosslinked polyolefin resin as described in claim 7, wherein the gel fraction of the decrosslinked polyolefin resin is less than or equal to 2 wt%, and the elongation is greater than or equal to 100%.

13. The method for preparing the decrosslinked polyolefin resin as described in claim 7, wherein the weight-average molecular weight of the decrosslinked polyolefin resin is greater than or equal to 50,000 g / mol.

Images