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

Abstract

The present invention provides a decrosslinked polyolefin resin having a gel fraction of less than or equal to 2 wt% and a uniformity (U) of greater than or equal to 30, wherein the uniformity (U) is defined as Equation 1: U = 2E / (C×D) --- (1) where E is the elongation of the decrosslinked polyolefin resin (in %), C is the gel fraction of the decrosslinked polyolefin resin (in wt%), and D is the polymer dispersion index (PDI) of the decrosslinked polyolefin resin.

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 (having low gel fraction and good uniformity) obtained from the recovery of crosslinked polyolefin resins, 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 low gel fraction and a high elongation, a composition comprising the same, 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 gel fraction of less than or equal to 2 wt% and a uniformity (U) of greater than or equal to 30, wherein the uniformity (U) is defined as Equation 1:

[0013] U = 2E / (C×D) ---(1)

[0014] Where E is the elongation of the decrosslinked polyolefin resin (in %), C is the gel fraction of the decrosslinked polyolefin resin, and D is the polymer dispersion index (PDI) of the decrosslinked polyolefin resin.

[0015] 2. In Example 1, the polymer dispersion index (PDI) of the decrosslinked polyolefin may be less than or equal to about 5.

[0016] 3. In Examples 1 and 2, the elongation of the decrosslinked polyolefin resin may be greater than or equal to 100%.

[0017] 4. In Examples 1 to 3, the weight-average molecular weight (Mw) of the decrosslinked polyolefin resin may be greater than or equal to 50,000 g / mol.

[0018] 5. In Examples 1 to 4, the content (Wa) of the resin component with a weight-average molecular weight (Mw) less than or equal to 10,000 g / mol in the decrosslinked polyolefin resin may be about 1 wt% to about 10 wt%.

[0019] 6. In Examples 1 to 5, the content (Wb) of the resin component with a weight-average molecular weight (Mw) greater than or equal to 500,000 g / mol in the decrosslinked polyolefin resin may be from about 0.5 wt% to about 15 wt%.

[0020] 7. In Examples 1 to 6, the content of resin components with a weight-average molecular weight (Mw) greater than or equal to 100,000 in the decrosslinked polyolefin resin may be greater than or equal to about 15 wt.

[0021] 8. Another embodiment of the invention relates to a composition. The resin composition comprises the decrosslinked polyolefin resin described in any of Examples 1 to 7.

[0022] 9. In Example 8, the composition further comprises a cross-linked polyolefin resin.

[0023] 10. 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 give the decrosslinked polyolefin resin a uniformity (U) greater than or equal to 30, and the uniformity (U) is defined as Equation 1:

[0024] U = 2E / (C×D) ---(1)

[0025] Where E is the elongation of the decrosslinked polyolefin resin (in %), C is the gel fraction of the decrosslinked polyolefin resin (in wt%), and D is the polymer dispersion index (PDI) of the decrosslinked polyolefin resin.

[0026] 11. In Example 10, the temperature at which the crosslinked polyolefin resin is extruded by a twin-screw extruder can be from about 220°C to about 350°C.

[0027] 12. In Examples 10 and 11, the cross-linked polyolefin resin includes peroxide cross-linked polyolefin resin, electron beam cross-linked polyolefin resin, or silane cross-linked polyolefin resin.

[0028] 13. In claims 10 to 12, 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%.

[0029] 14. In Examples 10 to 13, the weight-average molecular weight of the decrosslinked polyolefin resin may be greater than or equal to about 50,000 g / mol.

[0030] [Invention Benefits]

[0031] Embodiments of the present invention provide a decrosslinked polyolefin resin having low gel fraction, high elongation and uniform molecular weight distribution, a composition containing the same, and a method for preparing the same.

Implementation Method

[0033] 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.

[0034] 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.

[0035] Here, a 3D-GPC (refractive index, viscosity and light scattering detector, HT-GPC 1260, Agilent Technologies) is used to measure the weight-average molecular weight (Mw), number-average molecular weight (Mn), and polymer dispersion index (PDI).

[0036] The decrosslinked polyolefin resin and its preparation method according to embodiments of the present invention will be described in detail here.

[0037] This invention relates to decrosslinked polyolefin resin obtained from the recovery of crosslinked polyolefin resin, resin compositions containing the same, and methods for preparing the same.

[0038] 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.

[0039] 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.

[0040] The uniformity (U) of the decrosslinked polyolefin resin of the present invention is greater than or equal to 30, as defined in Formula 1.

[0041] U = 2E / (C×D) ---(1)

[0042] where E is the elongation of the decrosslinked polyolefin resin (in %), C is the gel fraction of the decrosslinked polyolefin resin (in wt%), and D is the polymer dispersion index (PDI) of the decrosslinked polyolefin resin.

[0043] In some embodiments, the uniformity (U) of the decrosslinked polyolefin resin may be greater than or equal to about 40, for example, about 50 to about 3,000, specifically about 50 to about 2,500. The uniformity (U) of the decrosslinked polyolefin resin is preferably about 80 to about 2,500, specifically about 200 to about 2,500, and more preferably about 300 to about 2,000. Decrosslinked polyolefin resins in this range have good decrosslinking characteristics and ensure that their physical properties are close to those of the polyolefin before crosslinking, thereby exhibiting good recyclability. In some embodiments, the uniformity (U) of the decrosslinked polyolefin resin may be 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1,000, 1,050, 1,100, 1,150, 1,200, 1,250, 1,300, or 1,350.

[0044] 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 from about 0.001 wt% to about 0.5 wt%. Decrosslinked polyolefin resins in this range may have good processability, rigidity, and recyclability.

[0045] The elongation of the decrosslinked polyolefin resin can be greater than or equal to about 100%, for example, greater than or equal to about 200%, specifically about 300% to about 650%.

[0046] 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. In some embodiments, the weight-average molecular weight (Mw) of the decrosslinked polyolefin resin may be 60,000 g / mol, 70,000 g / mol, 80,000 g / mol, 90,000 g / mol, 100,000 g / mol, 110,000 g / mol, 120,000 g / mol, 130,000 g / mol, 140,000 g / mol, 150,000 g / mol, 160,000 g / mol, 170,000 g / mol, 180,000 g / mol, 190,000 g / mol, or 200,000 g / mol.

[0047] The polymer dispersion index (PDI) of the decrosslinked polyolefin resin is less than or equal to about 5, for example, about 1 to about 4.8, specifically about 1.5 to about 4.7. Decrosslinked polyolefin resins in this range can have good uniformity.

[0048] In some embodiments, the content (Wa) of resin components with a weight-average molecular weight (Mw) less than or equal to 10,000 g / mol in the decrosslinked polyolefin resin can be from about 1 wt% to about 10 wt%, for example, from about 1.5 wt% to about 6 wt%, specifically from about 2 wt% to about 5.7 wt%. Decrosslinked polyolefin resins within this range have good mechanical properties. For example, the content (Wa) of resin components with a weight-average molecular weight (Mw) less than or equal to 10,000 g / mol in the decrosslinked polyolefin resin can be about 2.0 wt%, 2.5 wt%, 3.0 wt%, 3.5 wt%, 4.0 wt%, 4.5 wt%, 5.0 wt%, 5.5 wt%, 6.0 wt%, 6.5 wt%, 7.0 wt%, 7.5 wt%, or 8.0 wt%.

[0049] The content (Wb) of the resin component with a weight-average molecular weight (Mw) greater than or equal to 500,000 g / mol in the decrosslinked polyolefin resin may be from about 0.5 wt% to about 15 wt%, for example from about 1 wt% to about 12 wt%, specifically from about 1.1 wt% to about 10 wt%. Decrosslinked polyolefin resins in this range may have good mechanical properties. In some embodiments, the content (Wb) of the resin component with a weight-average molecular weight (Mw) greater than or equal to 500,000 g / mol in the decrosslinked polyolefin resin may be about 1.0 wt%, 1.5 wt%, 2.0 wt%, 2.5 wt%, 3.0 wt%, 3.5 wt%, 4.0 wt%, 4.5 wt%, 5.0 wt%, 5.5 wt%, 6.0 wt%, 6.5 wt%, 7.0 wt%, or 7.5 wt%.

[0050] In some embodiments, the content of resin components with a weight-average molecular weight (Mw) greater than or equal to 100,000 g / mol in the decrosslinked polyolefin resin may be greater than or equal to about 15 wt%, specifically greater than or equal to about 20 wt%, for example, about 20 wt% to about 50 wt%. Decrosslinked polyolefin resins in this range may have good mechanical properties. In some embodiments, the content of resin components with a weight-average molecular weight (Mw) greater than or equal to 100,000 g / mol in the decrosslinked polyolefin resin may be 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, or 50 wt%.

[0051] Decrosslinked polyolefin resins can have good processability and mechanical properties.

[0052] In some embodiments, the decrosslinked polyolefin resin may be a decrosslinked product of peroxide-crosslinked polyolefin resin, electron beam-crosslinked polyolefin resin, or silane-crosslinked polyolefin resin. The polyolefin resin 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. The polyolefin may include ultra-low density polyethylene, low density polyethylene, linear low density polyethylene, intermediate 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 described above.

[0053] In some embodiments, the decrosslinked polyolefin resin may conform to Formula 2.

[0054] Approximately 45 ≤ G0' / G' ≤ Approximately 2,000 ---(2)

[0055] 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.

[0056] In some embodiments, G0' / G' may 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. Decrosslinked polyolefin resins in this range may have good decrosslinking properties.

[0057] In some embodiments, the decrosslinked polyolefin resin may conform to Formula 3.

[0058] 35 ≤ V0 / V ≤ 3,000 ---(3)

[0059] 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.

[0060] Here, the sample can be 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 to confirm the complex viscosity (unit: Pa·s) before and after decrosslinking.

[0061] 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. Decrosslinked polyolefin resins in this range may have good decrosslinking properties.

[0062] In some embodiments, the tensile strength of the decrosslinked polyolefin resin is greater than or equal to about 200 kgf / cm2, preferably about 250 kgf / cm2 to about 500 kgf / cm2, and is measured according to ASTM D638.

[0063] In some embodiments, the melt index of the decrosslinked polyolefin resin is from about 0.005 g / 10 min to about 10 g / 10 min, preferably from about 0.01 g / 10 min to about 5 g / 10 min. The melt index can be measured according to ASTM D1238 at a temperature of 190°C and a load of 2.16 kg. In some embodiments, the melt index of the decrosslinked polyolefin resin is 0.1 g / 10 min, 0.5 g / 10 min, 1.0 g / 10 min, 1.5 g / 10 min, 2.0 g / 10 min, 2.5 g / 10 min, 3.0 g / 10 min, 3.5 g / 10 min, or 4.0 g / 10 min.

[0064] 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.

[0065] Another embodiment of the present invention relates to a method for preparing decrosslinked polyolefin resin. The method includes twin-screw extrusion of crosslinked polyolefin resin to achieve a uniformity (U) of the decrosslinked polyolefin resin greater than or equal to 30, defined as in Formula 1:

[0066] U = 2E / (C×D) ---(1)

[0067] Where E is the elongation of the decrosslinked polyolefin resin (in %), C is the gel fraction of the decrosslinked polyolefin resin (in wt%), and D is the polymer dispersion index (PDI) of the decrosslinked polyolefin resin.

[0068] In some embodiments, the uniformity (U) of the decrosslinked polyethylene hydrocarbon is greater than or equal to 40, for example, about 50 to about 3,000, preferably about 80 to about 2,500, specifically about 200 to about 2,500, and more preferably about 300 to about 2,000. Within this range, the decrosslinked polyolefin resin can have good decrosslinking characteristics and can ensure that its physical properties are similar to those of the polyolefin before decrosslinking, thereby having good recyclability.

[0069] The temperature at which the crosslinked polyolefin resin is extruded by a twin-screw extruder can be from about 220°C to about 350°C, preferably from about 250°C to about 330°C. Within this temperature range, the degree of molecular weight reduction can be minimized, and the decrosslinked polyolefin resin can be ensured to have good mechanical properties and a low gel fraction.

[0070] In some embodiments, the crosslinked polyolefin resin may include, but is not limited to, peroxide crosslinked polyolefin resin, electron beam crosslinked polyolefin resin, or silane crosslinked polyolefin resin. For example, the polyolefin resin 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 described above.

[0071] 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]

[0072] Example 1 Cross-linked polyethylene resin (XLPE) was decrosslinked and extruded at 330°C using a twin-screw extruder (Φ: 30 mm, SM Platek Co., Ltd.) with the extruder die temperature at 300°C to prepare decrosslinked polyethylene resin with a uniformity (U) of 88, as defined in Formula 1.

[0073] Example 2 Decrosslinked polyethylene resin was prepared in the same manner as in Example 1, except that the decrosslinking extrusion temperature was 330°C and the extruder die temperature was 270°C, so that the uniformity of the decrosslinked polyethylene resin was 551, as defined in Formula 1.

[0074] Example 3 Decrosslinked polyethylene resin was prepared in the same manner as in Example 1, except that the decrosslinking extrusion temperature was 250°C and the extruder die temperature was 250°C.

[0075] Example 4 Decrosslinked polyethylene resin was prepared in the same manner as in Example 1, except that the decrosslinking extrusion temperature was 330°C and the extruder die temperature was 330°C.

[0076] Comparative Example 1 uses cross-linked polyethylene resin (XLPE), which has not been decrosslinked and extruded.

[0077] 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.

[0078] Comparative Example 3: 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.

[0079] Comparative Example 4: Decrosslinked polyethylene resin was prepared in the same manner as in Example 1, except that a twin-screw extruder was used to perform the decrosslinking extrusion at a temperature of 230°C, so that the uniformity of the decrosslinked polyethylene resin was 28, as defined in Formula 1.

[0080] The properties of the decrosslinked polyethylene resins prepared in the Examples and Comparative Examples were evaluated, and the results are shown in Table 1.

[0081] (1) Gel fraction (in wt%)

[0082] 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.

[0083] (2) Uniformity (U)

[0084] The gel fraction (in wt%) and elongation (in %) obtained by the above method can be used to evaluate the uniformity according to Equation 1.

[0085] U = 2E / (C×D) ---(1)

[0086] Where E is the elongation of the decrosslinked polyolefin resin (in %), C is the gel fraction of the decrosslinked polyolefin resin (in wt%), and D is the polymer dispersion index (PDI) of the decrosslinked polyolefin resin.

[0087] (3) Polymer Dispersion Index (PDI) and Molecular Weight

[0088] The weight-average molecular weight (Mw) and number-average molecular weight (Mn) can be confirmed using 3D-GPC (refractive index, viscosity, and light scattering detector, HT-GPC, Agilent Technologies), and the Mw / Mn ratio can be calculated to obtain the polymer dispersion index (PDI). 2,4-Trichlorobenzene (TCB) is used as the solvent here. Specifically, a 10 mg / 10 mL decrosslinked polyethylene resin was pretreated at 160°C for 2 hours and then filtered to measure the molecular weight of each of the prepared decrosslinked polyethylene resins. Furthermore, a molecular weight distribution curve was plotted based on the measurement results to obtain the content (wt%) of the resin component corresponding to a specific molecular weight range.

[0089] (4) Melt index (unit: g / 10 min)

[0090] The melt flow index was measured according to ASTM D1238 at a temperature of 190°C and a load of 2.16 kg.

[0091] Table 1 Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 gel fraction (wt%) 0.2 0.2 0.2 0.2 >80 wt% 0.2 2.5 1.7 Uniformity (U) 88 551 1332 31 0.6> 15 27 28 Elongation (%) 28 149 626 15 112 3 390 120 Melt Flow Index 3.5 3.1 0.3 3.9 Unmeasurable Greater than or equal to 100 1.1 0.003 Mw 79,567 83,609 172,437 78,382 Unmeasurable 56,865 111,834 214,320 PDI 3.2 2.7 4.7 4.6 Unmeasurable 2.0 11.4 5 Content (wt%) (Wb) of resin components with Mw greater than or equal to 500,000 g / mol 1.0 1.2 7.1 1.2 Unmeasurable 0.4 3 10.3 Content (wt%) (Wa) of resin components with Mw less than or equal to 10,000 g / mol 5.6 4.4 3.9 8.0 Unmeasurable 4.5 twenty one 2.5 Content (wt%) of resin components with Mw greater than or equal to 10,000 g / mol 22.8 23.5 41.1 20.8 Unmeasurable 7.1 34.2 46.5

[0092] As shown in Table 1, the decrosslinked polyethylene resins prepared in Examples 1 to 3 exhibit good uniformity (decrosslinking characteristics) and significantly low gel fraction. Conversely, the gel fraction of the crosslinked polyethylene resin prepared in Comparative Example 1 and the decrosslinked polyethylene resins prepared in Comparative Examples 3 and 4 is higher than that of the decrosslinked polyethylene resins in the examples, and the polyethylene resins prepared in Comparative Examples 1 to 4 exhibit low uniformity. The decrosslinked polyethylene resin prepared in Comparative Example 3 has a high PDI, such as greater than 10. Although the decrosslinked polyethylene resin prepared in Comparative Example 2 has a low gel fraction, it also exhibits significantly low elongation.

[0093] 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.

[0094] Although this disclosure has been disclosed above with reference to several embodiments, it is not intended to limit this disclosure. Anyone with ordinary knowledge in the art can make any modifications and alterations without departing from the spirit and scope of this disclosure. Therefore, the scope of protection of this disclosure shall be determined by the appended claims. [Simplified Explanation of the Diagram]

[0032] None

Claims

1. A decrosslinked polyolefin resin having a gel fraction of less than or equal to 2 wt% and a uniformity (U) of greater than or equal to 30, wherein the uniformity (U) is defined as Equation 1: U = 2E / (C×D) --- (1) where E is the elongation of the decrosslinked polyolefin resin (in %), C is the gel fraction of the decrosslinked polyolefin resin, and D is the polymer dispersion index (PDI) of the decrosslinked polyolefin resin, wherein the polymer dispersion index (PDI) of the decrosslinked polyolefin is from 1 to 4.

8.

2. The decrosslinked polyolefin resin as claimed in claim 1, wherein the elongation of the decrosslinked polyolefin resin is greater than or equal to 100%.

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

4. The decrosslinked polyolefin resin as claimed in claim 1, wherein the content (Wa) of the resin component with a weight-average molecular weight (Mw) less than or equal to 10,000 g / mol in the decrosslinked polyolefin resin is from 1 wt% to 10 wt%.

5. The decrosslinked polyolefin resin as claimed in claim 1, wherein the content (Wb) of the resin component with a weight-average molecular weight (Mw) greater than or equal to 500,000 g / mol in the decrosslinked polyolefin resin is from 0.5 wt% to 15 wt%.

6. The decrosslinked polyolefin resin as claimed in claim 1, wherein the content of the resin component with a weight-average molecular weight (Mw) greater than or equal to 100,000 in the decrosslinked polyolefin resin is greater than or equal to 15 wt.

7. A composition comprising the decrosslinked polyolefin resin as described in any one of claims 1 to 6.

8. The composition as claimed in claim 7 further comprises a cross-linked polyolefin resin.

9. A method for preparing a decrosslinked polyolefin resin, comprising: A cross-linked polyolefin resin is extruded by a twin-screw extruder to give the decross-linked polyolefin resin a uniformity (U) greater than or equal to 30, and the uniformity (U) is defined as Equation 1: U = 2E / (C×D) --- (1) where E is the elongation of the decross-linked polyolefin resin (in %), C is the gel fraction of the decross-linked polyolefin resin (in wt%), and D is the polymer dispersion index (PDI) of the decross-linked polyolefin resin, wherein the polymer dispersion index (PDI) of the decross-linked polyolefin is from 1 to 4.

8.

10. The method for preparing the decrosslinked polyolefin resin as described in claim 9, wherein the temperature at which the crosslinked polyolefin resin is extruded by a twin-screw extruder is 220°C to 350°C.

11. A method for preparing a decrosslinked polyolefin resin as described in claim 9, wherein the crosslinked polyolefin resin includes a peroxide crosslinked polyolefin resin, an electron beam crosslinked polyolefin resin, or a silane crosslinked polyolefin resin.

12. The method for preparing the decrosslinked polyolefin resin as claimed in claim 9, wherein the decrosslinked polyolefin resin has a gel fraction of less than or equal to 2 wt% and an elongation of greater than or equal to 100%.

13. The method for preparing the decrosslinked polyolefin resin as described in claim 9, wherein the weight-average molecular weight of the decrosslinked polyolefin resin is greater than or equal to 50,000 g / mol.