CN110066365B

CN110066365B - Preparation method of functionalized polyethylene

Info

Publication number: CN110066365B
Application number: CN201810058405.9A
Authority: CN
Inventors: 吴文清; 王靖岱; 韩国栋; 戴进成; 李海涛; 胡晓波; 王晓飞; 蒋斌波; 王建斌; 孙婧元; 王晓丽; 黄正梁; 李孝博; 刘焕毅; 崔宇辉; 王静; 冯冠男; 杨遥
Original assignee: China Petroleum and Chemical Corp; Zhejiang University ZJU
Current assignee: China Petroleum and Chemical Corp; Zhejiang University ZJU
Priority date: 2018-01-22
Filing date: 2018-01-22
Publication date: 2021-11-16
Anticipated expiration: 2038-01-22
Also published as: CN110066365A

Abstract

The invention discloses a preparation method of functionalized polyethylene. The method comprises the following steps: introducing a first ethylene feed and a polar monomer into a first reactor, and carrying out a first polymerization reaction on the first ethylene feed and the polar monomer under the action of a catalyst to obtain a polar modified polyethylene; and introducing the material in the first reactor, a second ethylene feed and a nonpolar monomer into a second reactor to perform a second polymerization reaction to obtain the functionalized polyethylene. The finally obtained polyethylene has good basic mechanical properties and good performances such as adhesion and the like endowed by polar groups, and can meet the requirements in the application field of 3D printing materials.

Description

Preparation method of functionalized polyethylene

Technical Field

The invention relates to the field of polyethylene preparation, and in particular relates to a preparation method of functionalized polyethylene.

Background

The polyethylene material is one of the most used high molecular materials at present, and can improve the structural performance of the polyethylene, increase the variety and enlarge the application range by copolymerizing with non-polar monomers such as alpha-olefin, conjugated olefin and the like. However, with the progress of technology, because of the characteristics of non-polarity and low surface energy, the traditional polyethylene can not meet the use requirements in the fields of industry, agriculture, medical treatment, construction, civil life and the like, so that the polyethylene functionalization becomes a hot spot of academic research. In addition, polar groups have obvious influence on the performance of polyethylene materials, and the polyethylene can be functionalized by directly introducing the polar groups into the main chain of the polyethylene through the copolymerization reaction of ethylene and polar monomers, so that the polyethylene is endowed with good cohesiveness, wettability, printing property, compatibility with other polar polymers and the like.

The polyethylene functionalization method mainly comprises the following steps: ethylene and polar monomer are directly copolymerized, and the graft modification of the existing polyolefin product is realized. The direct copolymerization method is to directly introduce functional groups into the main chain of the polymer, and the method is completed in one step and has ideal efficiency. But the lewis acid component of the catalyst is easily complexed with N, O in the polar monomer and the lone electron pair of the halogen, affecting the electronic reaction of these components with the double bond, thereby reducing the activity of the active polymerization site of the complex formed by the catalyst and the functional group on the polar monomer. The graft modification method has low requirements on process conditions, simple equipment and mature technology. However, compared with the direct copolymerization method, the monomer utilization rate of the graft polymerization is low, and the defects of more side reactions, complex structure, difficult characterization and the like exist.

In order to ensure that the polyethylene realizes functionalization on the basis of having good basic mechanical properties, different reaction environments can be constructed in a reactor by utilizing conditions of different forms and the like of reaction materials, and polyethylene products with different structures are obtained. For example, polyethylene having various properties can be obtained by subjecting a catalyst or a polymer having an active site to two or more different reaction conditions in a double or multiple reactors connected in series to allow the reaction to proceed continuously. The series reaction method is a method mainly used for producing high-performance polyethylene in industry at present. However, the process of these reactors in series is limited to the production of polyethylene with both high molecular weight and low molecular weight, and cannot meet the requirements of the field of 3D printing materials for functionalized polyethylene.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a preparation method of functionalized polyethylene, wherein different gas composition conditions and reaction conditions are constructed through a serial polymerization reaction system formed by connecting two reactors in series, a first ethylene feed material is copolymerized with a polar monomer in a first reactor to realize the polar modification of polyethylene, and a second ethylene feed material is copolymerized with non-polar monomers such as alpha-olefin, conjugated olefin and the like in a second reactor to ensure that the polyethylene has basic mechanical properties such as toughness, mechanical strength and the like.

Accordingly, the object of the present invention is to provide a process for the preparation of a functionalized polyethylene, which process comprises:

introducing a first ethylene feed and a polar monomer into a first reactor, and carrying out a first polymerization reaction on the first ethylene feed and the polar monomer under the action of a catalyst to obtain a polar modified polyethylene; and

and introducing the material in the first reactor, a second ethylene feed and a nonpolar monomer into a second reactor to perform a second polymerization reaction to obtain the functionalized polyethylene.

The inventor of the application finds that the polyethylene product can be endowed with good adhesiveness, wettability, compatibility and the like by singly using the polar monomer to modify the polyethylene, but the strength of the product is insufficient, and the mechanical property is poor; when the nonpolar monomer is used alone to modify polyethylene, a polyethylene product with good mechanical strength and poor adhesive property can be obtained. One way to make the product have two excellent properties is to mechanically blend the polar modified polyethylene and the non-polar monomer modified polyethylene, but the blending effect is not ideal because the compatibility of the two modified polyethylenes is poor. The technical problem is effectively solved by the in-situ blending mode, and the functionalized polyethylene with excellent adhesive property and mechanical property can be obtained, so that the functionalized polyethylene can be suitably applied to 3D printing materials.

In a preferred embodiment of the present invention, the polar monomer is pretreated with a protecting agent and then passed into the first reactor.

According to the present invention, the polar monomer can be pretreated with a protecting agent before copolymerization, and the heteroatom N, O in the polar monomer, the halogen and the protecting agent are bonded to each other, whereby the coordination ability of the heteroatom can be reduced, and the copolymerization reaction can be performed more efficiently.

According to the invention, the protective agent is selected from one of triethylaluminum, trimethylchlorosilane, methyldiphenylchlorosilane and methylaluminoxane.

In another preferred embodiment of the present invention, the polar monomer comprises a double bond functional group and at least one hetero atom selected from oxygen, nitrogen and halogen, preferably comprises a double bond functional group and an oxygen hetero atom, and more preferably comprises maleic anhydride and at least one of methyl 5-norbornene-2-carboxylate and 2, 2-dimethyl-4-pentenol. Generally, oxygen-containing polar monomers > nitrogen-containing polar monomers > halogen-containing polar monomers with respect to their effect on the molecular orbital energy production of the olefin monomers. Therefore, the polar monomer is more preferably an oxygen-containing polar monomer, and still more preferably maleic anhydride.

In another preferred embodiment of the present invention, the non-polar monomer is selected from alpha-olefins and/or conjugated olefins, preferably at least one of butadiene, butene and hexene.

In another preferred embodiment of the present invention, the catalyst is selected from one of ziegler-natta catalyst, metallocene catalyst and late transition metal catalyst, preferably late transition metal catalyst.

The late transition metal catalyst is a metal complex olefin polymerization catalyst which takes late transition metal atoms such as nickel (II), palladium (II), iron (II), cobalt (II), ruthenium (II) and the like as active centers. The late transition metal catalyst has relatively weak oxygen affinity, is less sensitive to air and moisture, and has high activity of catalyzing olefin and cycloolefin polymerization. Compared with metallocene catalyst, post-transition metal catalyst has the advantages of good stability, low production cost, capability of producing new species of polyolefin, capability of synthesizing novel polymer with functional groups and the like, and the post-transition metal catalyst is relatively simple to synthesize and has higher yield, so the cost of the post-transition metal catalyst is far lower than that of the metallocene catalyst. Therefore, in the present invention, a late transition metal catalyst is preferably used, and a nickel (ii) late transition metal catalyst is more preferably used.

In another preferred embodiment of the invention, the molar ratio of the polar monomer to the first ethylene feed in the first reactor is between 0.01 and 0.3 and the molar ratio of the non-polar monomer to the second ethylene feed in the second reactor is between 0.01 and 0.15.

In another preferred embodiment of the present invention, the reaction pressure of the first polymerization reaction is from 1.5MPa to 10MPa, preferably from 6MPa to 8 MPa; the reaction temperature is 70-120 ℃, and preferably 90-100 ℃; the reaction pressure of the second polymerization reaction is 1.0MPa-10MPa, preferably 6MPa-8 MPa; the reaction temperature is 80-130 deg.C, preferably 90-100 deg.C.

The inventor of the present application has found that under the above temperature and pressure conditions, the efficiency and the product quality can be both considered, and the reaction conditions adopted in the first polymerization reaction and the second polymerization reaction are mild, so that the operation and the control are convenient.

In another preferred embodiment of the present invention, the polar modified polyethylene has a melt index of 90g/10min or less, preferably 40g/10min to 60g/10min, and a density of 0.9g/cm³-0.95g/cm³(ii) a The melt index of the functionalized polyethylene is below 120g/10min, preferably 20g/10min-40g/10 min; the density is 0.95g/cm³Below, it is preferably 0.94g/cm³-0.95g/cm³。

In another preferred embodiment of the present invention, the functionalized polyethylene has a tensile strength of 18MPa or more, preferably 18MPa to 30MPa, more preferably 18MPa to 25 MPa; the elongation at break is more than 48%, preferably 48% -60%, more preferably 48% -52%; the adhesive strength is 0.350N/mm or more, preferably 0.350N/mm to 0.450N/mm, more preferably 0.350N/mm to 0.400N/mm.

In another preferred embodiment of the present invention, the first reactor is a gas phase fluidized bed reactor and the second reactor is a gas phase fluidized bed or slurry or bulk polymerization reactor.

According to the invention, the gas-phase fluidized bed reactor can realize the continuous input and output of materials, so that the bed layer has good heat transfer performance, the temperature in the bed layer is uniform, and the gas-phase fluidized bed reactor is easy to control and is convenient for the continuous regeneration and the cyclic operation of the catalyst. Thus, preferably, the first reactor and the second reactor of the present invention are both gas phase fluidized bed reactors.

The process is simple, and the first reactor and the second reactor are directly connected through a pipeline without any degassing equipment. Preferably, the first reactor and the second reactor are connected in series to form a series polymerization system.

In another preferred embodiment of the present invention, a chain transfer agent and/or an antistatic agent is used in the first polymerization reaction and/or the second polymerization reaction. The molecular weight of the product can be suitably adjusted by using a chain transfer agent; the use of the antistatic agent can prevent the occurrence of explosion accidents due to the accumulation of static electricity in the polymerization apparatus.

According to the present invention, as the chain transfer agent, a chain transfer agent known to those skilled in the art may be used, and preferably at least one of hydrogen and a metal alkyl, and more preferably hydrogen is used. The antistatic agent may be one known to those skilled in the art, and is preferably at least one of aluminum distearate, ethoxylated amine, polysulfone copolymer, polymeric polyamine, and oil-soluble sulfonic acid.

In one embodiment of the present invention, the preparation method of the functionalized polyethylene comprises the following steps:

1) replacing the first reactor (R1) and the second reactor (R2) with nitrogen for a plurality of times, and then replacing for more than 2h by industrial ethylene;

2) introducing a first ethylene feed and polar monomer pretreated by a protective agent into a first reactor (R1) through a first feed pipeline (L1), carrying a catalyst and an antistatic agent into the first reactor (R1) through a second feed pipeline (L2) by using high-pressure (more than 20MPa) ethylene, and carrying out a first polymerization reaction on the first ethylene feed and the polar monomer in the first reactor (R1) under the action of the catalyst to obtain a polarized modified polyethylene;

3) intermittently introducing the solid material containing the polarized modified polyethylene and the material in the first reactor (R1) carrying the gas of the catalyst into a second reactor (R2) through a first discharge pipeline (L3);

4) feeding a second ethylene feed and a nonpolar monomer into a second reactor (R2) through a third feed pipeline (L4), and carrying out a second polymerization reaction on the polarized modified polyethylene, the second ethylene feed and the nonpolar monomer under the action of a catalyst to obtain a functionalized polyethylene;

5) the functionalized polyethylene produced was continuously discharged through a second discharge line (L5).

Preferably, in the step 2), the reaction pressure of the first polymerization reaction is 1.5MPa to 10.0 MPa; the reaction temperature is 70-120 ℃, and preferably 90-100 ℃; the molar ratio of the polar monomer to the first ethylene feed is from 0.01 to 0.3.

Preferably, in step 3), the volume ratio of the solid material containing the polar modified polyethylene and the gas carrying the catalyst is 10:1 to 1:1, preferably 3:1, and the discharge is performed 10 to 50 times per hour, preferably 30 times. Each discharge can be controlled manually or automatically, preferably automatically. When discharging, the valve (V1) is closed, the valves (V2) and (V3) are opened, and the solid material containing the polarized modified polyethylene is discharged into the first discharge pipeline (L3) by the driving force of the high-pressure ethylene and is introduced into the second reactor (R2).

Preferably, in step 4), the reaction pressure of the second polymerization reaction is 1.0MPa to 10.0MPa, preferably 8.0 MPa; the reaction temperature is 80-130 ℃, and preferably 90-100 ℃; the molar ratio of non-polar monomer to the second ethylene feed is from 0.01 to 0.15.

Preferably, in step 5), the functionalized polyethylene can be discharged to a post-processing treatment by using an existing method, such as one of a gravity discharge method, a rotary discharge method and a pressure blow-off method, preferably a gravity discharge method.

According to the invention, ethylene is sequentially copolymerized with polar monomers and nonpolar monomers, so that the generated functional polyethylene has good basic mechanical properties and good performances such as adhesion and the like endowed by polar groups, and can meet the requirements in the application field of 3D printing materials.

Drawings

FIG. 1 is a process flow diagram for the preparation of functionalized polyethylene in one embodiment of the present invention.

Description of reference numerals: r1 is the first reactor; r2 is the second reactor; l1 is a first feed line; l2 is a second feed line; l3 is a first discharge line; l4 is a third feed line; l5 is a second discharge line; v1, V2 and V3 are valves.

Detailed Description

The present invention is further described in the following examples, which should be construed as merely illustrative and not a limitation of the spirit and scope of the present invention.

The properties of the polyethylene were tested by the following methods:

the density of the polyethylene was tested according to ASTM D1928;

melt index (MFI) of polyethylene₂Tested according to ASTM D1238 at 190 ℃ under a load of 2.16 kg;

the adhesive strength of polyethylene was tested according to GB 2791-93;

the tensile strength and elongation at break of polyethylene were tested according to GB 1040-90.

Preparation example 1 preparation of catalyst

At 60 ℃,2, 6-dimethylaniline and hexanedione (the molar ratio is 3: l) react in a methanol solvent for 2.5h, and the product is frozen and crystallized to prepare the bis- (2, 6-dimethylphenyl) hexanediimine ligand. Stirring the solution under the nitrogen atmosphere, heating the anhydrous nickel bromide to 45 ℃ in ethanol, continuously stirring for 1h until the anhydrous nickel bromide is completely dissolved to obtain an ethanol solution of the anhydrous nickel bromide, dissolving the obtained ligand in dichloromethane, then adding the dichloromethane into the ethanol solution (the molar ratio of the ligand to the anhydrous nickel bromide is 1:1), and reacting for 6h at 45 ℃. The reaction solution was concentrated, and the concentrate was washed with n-hexane and then subjected to decantation. Removing the solvent in vacuum at 80 ℃ to prepare the catalyst of bis- (2, 6-dimethylphenyl) hexamethylene diimine nickel bromide [ C ]₆H₅N＝C(CH₃)C(C₃H₇)＝NC₆HS]NiBr₂。

Preparation example 2 preparation of polar monomer

10g of imidazole and 25g of maleic anhydride were dissolved in 250mL of dichloromethane to obtain a solution A, 11g of methylaluminoxane was added to 100mL of dichloromethane to obtain a solution B, and the solution B was slowly added to the solution A with continuous stirring at 40-60 ℃. After 2h stirring was stopped, water was added for layering, and the organic layer was rotary evaporated using a rotary evaporator to remove the solvent dichloromethane to give pretreated maleic anhydride.

Example 1

The preparation of functionalized polyethylene was carried out according to FIG. 1, in particular,

after replacing the first reactor (R1) and the second reactor (R2) (both reactors are the same size) of 80X 800mm with nitrogen several times, the reactors were replaced with a flow of ethylene for 4 h.

Feeding a first ethylene feed (with a feed pressure of 20.0MPa) and 50g of the pretreated maleic anhydride prepared in preparation example 2 into a first reactor (R1) through a first feed line (L1) (the molar ratio of the maleic anhydride to the first ethylene feed is 1:10), carrying 0.2g of the catalyst prepared in preparation example 1 into the first reactor (R1) through a second feed line (L2) by using 25MPa of high-pressure ethylene, controlling the reaction temperature to be 90 ℃ and the reaction pressure to be 8MPa, and carrying out a first polymerization reaction on the first ethylene feed and the maleic anhydride under the action of the catalyst to obtain a polarized modified polyethylene with a melt index of 47g/10 min; the density is 0.941g/cm³。

The solid material containing the poled modified polyethylene and the material in the first reactor (R1) carrying the gas of the catalyst are discharged 10 times per hour, and when the material is discharged, the valve (V1) is closed, the valves (V2) and (V3) are opened, the material is discharged by the driving force of the high-pressure ethylene, and the material enters the second reactor (R2) through the first discharge pipeline (L3).

And continuously feeding a second ethylene feed (with the feed pressure of 20.0MPa) and a nonpolar monomer butadiene (with the feed pressure of 20.0MPa) into a second reactor (R2) (the molar ratio of the butadiene to the second ethylene feed is 1:10) through a third feed pipeline (L4), controlling the reaction temperature to be 90 ℃ and the reaction pressure to be 8MPa, and carrying out a second polymerization reaction on the polarized modified polyethylene, the second ethylene feed and the butadiene under the action of a catalyst to obtain the functionalized polyethylene.

The functionalized polyethylene produced in the second reactor (R2) was continuously discharged through a second discharge line (L5), a buffer tank was used to collect the material, and the reaction was stopped after 2 hours. The resulting reaction product was a functionalized polyethylene product, and the results of the relevant performance tests are shown in table 1.

Example 2

A functionalized polyethylene was prepared in the same manner as in example 1, except that the amount of pretreated maleic anhydride was 80g (molar ratio of maleic anhydride to first ethylene feed was 1.6: 10); the melt index of the polar modified polyethylene obtained by the first polymerization reaction is 45g/10 min; the density is 0.943g/cm³(ii) a The results of the relevant performance tests on the finally obtained functionalized polyethylene products are shown in table 1.

Example 3

A functionalized polyethylene was prepared in the same manner as in example 1, except that the amount of maleic anhydride used was 120g (molar ratio of maleic anhydride to ethylene: 2.4: 10); the melt index of the polar modified polyethylene obtained by the first polymerization reaction is 41g/10 min; the density is 0.941g/cm³(ii) a The results of the relevant performance tests on the finally obtained functionalized polyethylene products are shown in table 1.

Example 4

Functionalized polyethylene was prepared in the same manner as in example 1, except that the molar ratio of butadiene to the second ethylene feed was 1.2: 10. The results of the relevant performance tests on the finally obtained functionalized polyethylene products are shown in table 1.

Example 5

Functionalized polyethylene was prepared in the same manner as in example 1, except that the molar ratio of butadiene to the second ethylene feed was 0.5: 10. The results of the relevant performance tests on the finally obtained functionalized polyethylene products are shown in table 1.

Comparative example 1

After several replacements of the second reactor (. PHI.80X 800 mm) (R2) with nitrogen, it was replaced by a flow of ethylene for 4 h.

Continuously feeding ethylene feed (with the feed pressure of 20MPa) and nonpolar monomer butadiene (with the feed pressure of 20MPa) into a reactor through a feed pipeline (the molar ratio of the butadiene to the ethylene feed is 1:10), controlling the reaction temperature at 90 ℃ and the reaction pressure at 8MPa, and carrying out polymerization reaction on the ethylene feed and the butadiene under the action of a catalyst to obtain polyethylene; continuously discharging the mixture through a discharge pipeline, collecting the materials by using a buffer tank, and stopping the reaction after 2 hours. The results of the relevant performance tests on the resulting polyethylene products are shown in table 1.

Comparative example 2

The first reactor (. PHI.80 X.800 mm) (R1) was purged several times with nitrogen and then purged with ethylene for 4 hours.

Feeding ethylene feed (with the feed pressure of 20.0MPa) and 50g of the pretreated maleic anhydride prepared in preparation example 2 into a reactor (R1) through a feed pipeline (the molar ratio of the maleic anhydride to the ethylene feed is 1:10), carrying 0.2g of the catalyst prepared in preparation example 1 into a first reactor (R1) through another feed pipeline by using 25MPa high-pressure ethylene, controlling the reaction temperature to be 90 ℃ and the reaction pressure to be 8MPa, and carrying out polymerization reaction on the ethylene feed and the maleic anhydride under the action of the catalyst to obtain polyethylene; continuously discharging the mixture through a discharge pipeline, collecting the materials by using a buffer tank, and stopping the reaction after 2 hours. The results of the relevant performance tests on the resulting polyethylene products are shown in table 1.

Comparative example 3

The polyethylene product obtained in comparative example 1 and the polyethylene product obtained in comparative example 2 were mechanically blended. The blending conditions were: melt blending was carried out at 180 ℃ using a micro mixer.

The results of the related property tests of the product obtained by mechanical blending are shown in table 1.

TABLE 1 results of the Performance test of the polyethylene products obtained in the examples and comparative examples

As can be seen from the data in Table 1, the functionalized polyethylene products prepared by the present invention have good basic mechanical properties and adhesive properties, while the polyethylene products of comparative examples 1-3 do not have good balance. Therefore, the functionalized polyethylene product can better meet the requirements of the application field of 3D printing materials.

Although the present invention has been described in detail, modifications within the spirit and scope of the invention will be apparent to those skilled in the art. Further, it should be understood that the various aspects recited herein, portions of different embodiments, and various features recited may be combined or interchanged either in whole or in part. In the various embodiments described above, those embodiments that refer to another embodiment may be combined with other embodiments as appropriate, as will be appreciated by those skilled in the art. Furthermore, those skilled in the art will appreciate that the foregoing description is by way of example only, and is not intended to limit the invention.

Claims

1. A method of preparing a functionalized polyethylene, comprising:

2. The method of claim 1, wherein the polar monomer is pretreated with a protecting agent and then introduced into the first reactor.

3. The method according to claim 2, wherein the protective agent is at least one selected from the group consisting of triethylaluminum, trimethylchlorosilane, methyldiphenylchlorosilane, and methylaluminoxane.

4. The production method according to any one of claims 1 to 3, wherein the polar monomer comprises a double bond functional group and at least one hetero atom selected from oxygen, nitrogen and halogen; the non-polar monomer is an alpha-olefin and/or a conjugated olefin.

5. The method of claim 4, wherein the polar monomer comprises a double bond functional group and an oxygen heteroatom.

6. The production method according to claim 4, wherein the polar monomer is at least one of maleic anhydride and methyl 5-norbornene-2-carboxylate and 2, 2-dimethyl-4-pentenol.

7. The method according to claim 4, wherein the nonpolar monomer is selected from at least one of butadiene, butene and hexene.

8. The method according to any one of claims 1 to 3, wherein the catalyst is one selected from the group consisting of Ziegler-Natta catalysts, metallocene catalysts and late transition metal catalysts.

9. The method of claim 8, wherein the catalyst is a late transition metal catalyst.

10. The process of any one of claims 1-3, wherein the molar ratio of the polar monomer to the first ethylene feed in the first reactor is from 0.01 to 0.3, and the molar ratio of the non-polar monomer to the second ethylene feed in the second reactor is from 0.01 to 0.15.

11. The production method according to any one of claims 1 to 3, wherein the reaction pressure of the first polymerization reaction is 1.5MPa to 10 MPa; the reaction temperature is 70-120 ℃; the reaction pressure of the second polymerization reaction is 1.0MPa-10 MPa; the reaction temperature is 80-130 ℃.

12. The production method according to claim 11, wherein the reaction pressure of the first polymerization reaction is 6MPa to 8 MPa; the reaction temperature is 90-100 ℃; the reaction pressure of the second polymerization reaction is 6MPa-8 MPa; the reaction temperature is 90-100 ℃.

13. The production method according to any one of claims 1 to 3, wherein the melt index of the polar modified polyethylene is 90g/10min or less; the density was 0.9g/cm³-0.95g/cm³(ii) a The melt index of the functionalized polyethylene is below 120g/10 min; the density is 0.95g/cm³The following.

14. The production method according to claim 13, wherein the melt index of the polar modified polyethylene is 40g/10min to 60g/10 min; the melt index of the functionalized polyethylene is 20g/10min-40g/10 min; the density was 0.94g/cm³-0.95g/cm³。

15. The production method according to any one of claims 1 to 3, wherein the functionalized polyethylene has a tensile strength of 18MPa or more, an elongation at break of 48% or more, and an adhesive strength of 0.350N/mm or more.

16. The method of any one of claims 1-3, wherein the first reactor is a gas phase fluidized bed reactor and the second reactor is a gas phase fluidized bed or slurry or bulk polymerization reactor.

17. The method of claim 16, wherein the first reactor and the second reactor are directly connected by piping.

18. The production method according to any one of claims 1 to 3, characterized in that a chain transfer agent and/or an antistatic agent is used in the first polymerization reaction and/or the second polymerization reaction.