JP4879451B2 - Olefin polymer and process for producing the same - Google Patents

Description

【図面の簡単な説明】
【図１】重合工程を単段で行う場合を示す説明図である。
【図２】重合工程を２段で行う場合を示す説明図である。
【図３】配位子除去工程の一例を表す説明図である。
【図４】配位子除去工程の他の例を表す説明図である。
【符号の説明】
１０、４０ … 抜出ライン
１１、２１ … 流動層反応器
１２、２２ … 供給ライン
１８、２８ … 流動層
５１、５４ … サイロ
５２ … 押出機
５７ … 乾燥器[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an olefin polymer and a method for producing the same, and more specifically, an olefin polymer having a low content of components that generate odor and components that change taste, and such olefin polymers. The present invention relates to a method for producing an olefin polymer that can be produced efficiently.
[0002]
[Prior art]
Olefin polymers such as polyethylene, polypropylene, ethylene / α-olefin copolymers, and propylene / α-olefin copolymers are widely used as various molding materials. The required properties of olefin polymers differ depending on the application. For example, in food applications, subtle smells and tastes are important, and it is required not to impair the flavor of food.
[0003]
By the way, when the olefin polymer is produced by vapor phase polymerization in the presence of a solid catalyst, the polymer can be obtained in the form of particles, and after the polymerization, a polymer precipitation step or a solvent separation step, etc. Is no longer necessary. Therefore, it is known that the manufacturing process can be simplified and the manufacturing cost can be reduced. However, an olefin polymer produced by a gas phase polymerization method may generate an odor during heat processing, and may affect the flavor and the like particularly in food applications that place an emphasis on subtle odor or taste. In such applications, use has been limited.
[0004]
As a method of reducing the odor of the olefin polymer obtained by the gas phase polymerization method and the influence on the taste when used in food applications, for example, in Japanese Patent Laid-Open No. 10-45824, a metallocene catalyst is used. A method is described in which the olefin polymer obtained is brought into contact with water vapor or the like to decompose the cyclopentadienyl ligand in the polymer, thereby reducing the odor generated from the olefin polymer during molding. Yes.
[0005]
By such a method, the odor of the olefin polymer can be considerably reduced, but in recent years, further odor reduction has been desired for food applications and the like.
Under such circumstances, as a result of the study by the present inventors, when producing an olefin polymer by a gas phase polymerization method, a polymerization reaction is performed in the presence of a saturated aliphatic hydrocarbon in a fluidized bed reactor, And it came to complete this invention, discovering that an odor was reduced greatly by contacting the obtained polymer with water vapor | steam etc. FIG.
[0006]
[Problems to be solved by the invention]
That is, an object of the present invention is to provide an olefin polymer having a low content of a component that generates odor and a component that changes taste, and a method for producing the same.
[0007]
[Means for Solving the Problems]
The olefin polymer according to the present invention is an olefinic (co) polymer obtained by polymerizing at least one olefin selected from ethylene and an α-olefin having 3 to 20 carbon atoms in the presence of a metallocene catalyst. The polymer is characterized in that the n-decane soluble content is 10 wt% or less, and the content of the ligand having a cyclopentadienyl skeleton is 5 wt ppb or less.
[0008]
The olefin polymer is preferably a copolymer of ethylene and at least one α-olefin selected from α-olefins having 3 to 20 carbon atoms.
The olefin polymer has a density of 0.930 g / cm.^ThreeThe following is preferable.
[0009]
Furthermore, the said olefin polymer polymerizes (co) polymerizes the 1 type (s) or 2 or more types of olefin chosen from ethylene and a C3-C20 alpha olefin using a fluidized bed reactor. It is preferable that it is obtained by this.
Furthermore, the olefin polymer has ethylene and carbon atoms of 3 to 20 while a saturated aliphatic hydrocarbon having 2 to 10 carbon atoms is present in the fluidized bed reactor at a concentration of 2 to 30 mol%. One or more olefins selected from α-olefins are (co) polymerized, and then the obtained (co) polymer is contacted with a ligand decomposing agent, and then contacted with a ligand decomposing agent. In addition, it is preferable to be obtained by heating the (co) polymer.
[0010]
The method for producing an olefin polymer according to the present invention uses a fluidized bed reactor to convert one or more olefins selected from ethylene and an α-olefin having 3 to 20 carbon atoms into a metallocene catalyst. A method for producing an olefin polymer by (co) polymerization in the gas phase in the presence of
A polymerization step of (co) polymerizing the olefin while allowing the saturated aliphatic hydrocarbon to be present in the fluidized bed reactor at a concentration of 2 to 30 mol%;
A step of bringing the obtained (co) polymer into contact with a ligand decomposing agent, and a ligand removing step comprising a step of heating the (co) polymer brought into contact with the ligand decomposing agent.
It is characterized by having.
[0011]
In the present invention, the saturated aliphatic hydrocarbon is preferably supplied into the fluidized bed reactor in a gas-liquid two-phase coexistence state.
By the method for producing an olefin polymer, an olefin polymer having an n-decane soluble content of 10 wt% or less and a content of a ligand having a cyclopentadienyl skeleton of 5 wt ppb or less is produced. can do.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the olefin polymer and the production method thereof according to the present invention will be specifically described.
In the present invention, the term “polymerization” may be used to mean not only homopolymerization but also copolymerization, and the term “polymer” includes not only homopolymers but also copolymers. Sometimes used in meaning.
[0013]
[Olefin polymer]
The olefin polymer according to the present invention is a (co) polymer of at least one or two or more olefins selected from ethylene and an α-olefin having 3 to 20 carbon atoms.
Specific examples of the α-olefin having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1 -Dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicocene and the like. Among these, α-olefins having 3 to 10 carbon atoms, particularly 5 to 8 carbon atoms are preferably used.
[0014]
These olefins selected from ethylene and α-olefins having 3 to 20 carbon atoms can be used singly or in combination of two or more.
In the present invention, the olefin polymer is preferably a copolymer of ethylene and at least one α-olefin selected from α-olefins having 3 to 20 carbon atoms, more preferably ethylene and the number of carbon atoms. It is a copolymer with at least one α-olefin selected from 3 to 10 α-olefins.
[0015]
When the olefin polymer according to the present invention is a copolymer of at least two monomers selected from ethylene and an α-olefin having 3 to 20 carbon atoms, the content of each constituent unit is not particularly limited. For example, when the copolymer is a copolymer of ethylene and an α-olefin, the structural unit derived from ethylene is 80 to 99.6 mol%, preferably 93.8 to 98 mol%, α -It is desirable to contain the structural unit derived from an olefin in the ratio of 0.4-20 mol%, preferably 2-6.2 mol%.
[0016]
Further, in the present invention, a structural unit derived from ethylene and an α-olefin having 3 to 20 carbon atoms and a structural unit derived from polyenes as necessary may be contained, for example, a conjugate such as butadiene or isoprene. It may contain structural units derived from non-conjugated dienes such as dienes, 1,4-hexadiene, dicyclopentadiene, and 5-vinyl-2-norbornene.
[0017]
The olefin polymer according to the present invention has an n-decane soluble content of 10% by weight or less, preferably 5% by weight or less, more preferably 3% by weight or less. The lower limit of the n-decane soluble content is preferably 0% by weight, but is practically 0.1% by weight of the measurement limit.
An olefin polymer having an n-decane soluble content in the above range has a low content of low molecular weight components such as oligomers, so that odor is less likely to occur during molding, and the olefin polymer is used for food applications. When used, there is little loss of subtle smell or taste.
[0018]
The amount of n-decane soluble component is measured as follows. That is, 3 g of a polymer sample, 20 mg of 2,6-di-tert-butyl-4-methylphenol, and 500 ml of n-decane are placed in a 1 liter flask equipped with a stirrer, and dissolved by heating in an oil bath at 145 ° C. After the polymer sample has dissolved, it is cooled to room temperature over about 8 hours and then held on a 23 ° C. water bath for 8 hours. The precipitated polymer (n-decane insoluble part) and the n-decane solution containing the dissolved polymer are separated by filtration with a G-4 (or G-2) glass filter. The solution thus obtained is heated under the conditions of 10 mmHg and 150 ° C., and the polymer dissolved in the n-decane solution is dried until it becomes quantitative, and its weight is defined as the amount of n-decane soluble component.
[0019]
In the olefin polymer according to the present invention, the content of the ligand having a cyclopentadienyl skeleton is 5 wt ppb or less, preferably 2 wt ppb or less, more preferably 1 wt ppb or less. The lower limit of the content of the ligand having a cyclopentadienyl skeleton is preferably 0 weight ppb, but is substantially 1 weight ppb at the measurement limit.
[0020]
When the content of the ligand having a cyclopentadienyl skeleton is within the above range, odor is hardly generated at the time of molding, and when the olefin polymer is used for food, a subtle odor or taste is generated. There is little damage.
The content of the ligand having a cyclopentadienyl skeleton is measured as follows. That is, a ligand having a cyclopentadienyl skeleton is extracted using toluene, and identification and quantification are performed by gas mass using a calibration curve method.
[0021]
The olefin polymer according to the present invention has a number average molecular weight measured by gel permeation chromatography (GPC) usually in the range of 1,250 to 8,500, and Mw / Mn is usually 1.8 to 3.5. The density measured by the density gradient tube method is usually 0.930 g / cm.^ThreeOr less, preferably 0.880 to 0.930 g / cm^ThreeIt is in the range.
[0022]
As described above, the olefin polymer according to the present invention uses, for example, a fluidized bed reactor to gasify one or two or more olefins selected from ethylene and an α-olefin having 3 to 20 carbon atoms. It can be obtained by (co) polymerization.
More specifically, as will be described later, one or more olefins selected from ethylene and an α-olefin having 3 to 20 carbon atoms in the presence of a saturated aliphatic hydrocarbon in the fluidized bed reactor. Obtained by (co) polymerizing, then contacting the resulting (co) polymer with a ligand decomposing agent and then heating the (co) polymer contacted with the ligand decomposing agent. .
[0023]
[Method for producing olefin polymer]
The method for producing an olefin polymer according to the present invention includes a polymerization step of (co) polymerizing an olefin while a saturated aliphatic hydrocarbon is present in a fluidized bed reactor,
The obtained (co) polymer is brought into contact with a ligand decomposing agent, and then the ligand removing step of heating the (co) polymer brought into contact with the ligand decomposing agent is included.
[0024]
(Polymerization process)
In the polymerization step, in a fluidized bed in which solid particles containing a catalyst are maintained in a fluidized state by a gas stream containing a polymerized monomer flowing through the fluidized bed reactor, ethylene and carbon atoms of 3 as a polymerization monomer are present in the presence of the catalyst. When producing an olefin polymer by polymerizing in the gas phase with at least one olefin (polymerization monomer) selected from -20 α-olefins, a saturated aliphatic hydrocarbon in a gas-liquid mixed state together with the polymerization monomer Are introduced from the bottom of the fluidized bed reactor to carry out the polymerization reaction.
[0025]
Here, the polymerization process will be described in detail with reference to FIG. FIG. 1 shows the polymerization step, and the ligand decomposition step is omitted.
In the polymerization step, the catalyst is supplied from the line 15 in the fluidized bed reactor 11, and the polymerization monomer and saturated aliphatic hydrocarbon supplied from the supply line 12 are supplied from the supply port 9 at the bottom of the reactor to the bottom of the reactor. The dispersion plate 17 such as a perforated plate is blown into the fluidized bed 18 and discharged from the line 16 at the top of the reactor to be circulated in the reactor, and this gas flow (fluidized gas) causes solid particles (solid catalyst). In addition, the fluidized bed (reaction system) 18 is formed by maintaining the polymer in the fluidized state.
[0026]
In such a fluidized bed 18, polymer particles produced by polymerization of at least one olefin selected from ethylene and olefins having 3 to 20 carbon atoms are continuously or intermittently discharged from the reactor via the extraction line 10. And is supplied to the ligand decomposition step described later.
On the other hand, the gas discharged from the reactor 11 via the line 16 contains unreacted polymerization monomers, saturated aliphatic hydrocarbons, and the like. Usually, after being cooled, the reactor is supplied via the supply port 9 as a circulating gas. 11 is circulated.
[0027]
As described above, the fluidizing gas composed of the polymerization monomer and the circulating gas is introduced into the reactor 11 from the supply port 9 and is usually circulated at such a flow rate that the fluidized bed 18 can be maintained in a fluid state by the gas. However, the amount of gas introduced from the supply port 9 specifically determines the minimum fluidization speed of the fluidized bed U_mfWhen about 3U_mf~ 50U_mfDegree, preferably about 5U_mf~ 30U_mfIt is desirable that the flow rate be of the order. The fluidized bed 18 can also be stirred mechanically, for example, by using various types of stirrers such as a squid type stirrer, a screw type stirrer, and a ribbon stirrer.
[0028]
In the polymerization step, the polymerization can be performed in two or more stages by changing reaction conditions. Next, the polymerization process in the case where the polymerization is performed in two or more stages will be specifically described with reference to FIG. FIG. 2 shows only the polymerization step, and the ligand decomposition step is omitted.
When the polymerization is performed in two or more stages, for example, when the polymerization is performed in a multistage gas phase polymerization apparatus having two gas phase fluidized bed reactors connected in series, the polymerization is performed as follows.
[0029]
In the multistage gas phase polymerization apparatus, for example, as shown in FIG. 2, a first fluidized bed reactor 11 and a second fluidized bed reactor 21 are connected in series.
That is, the catalyst is supplied from the supply line 15 to the first fluidized bed reactor 11, and the gas containing the gaseous olefin (polymerization monomer) and saturated aliphatic hydrocarbon (fluidized gas) is supplied to the supply line 12. From the bottom of the first fluidized bed reactor 11 through the blower 13. The supplied fluidized gas is blown into the fluidized bed 18 through the dispersion plate 17 made of a porous plate or the like disposed in the vicinity of the bottom of the first fluidized bed reactor 11, and from above the fluidized bed reactor 11. It passes through the fluidized bed reactor 11 by being discharged. The solid particles (solid catalyst and produced polymer) are maintained in a fluidized state by the gas flow of the gas passing through the fluidized bed reactor 11 to form a fluidized bed 18.
[0030]
The produced polymer particles are extracted continuously or intermittently, and are solid-gas separated in the solid-gas separation containers 31 and 32. At this time, the valves 33 and 34 are appropriately controlled to open and close. The polymer particles extracted in this way are discharged to the transport line 25 by the operation of the valve 35 and sent to the second fluidized bed reactor 21 through the transport line 25.
[0031]
In addition, the unreacted gaseous olefin, saturated aliphatic hydrocarbon, and the like that have passed through the fluidized bed 18 are reduced in flow rate in the deceleration region 19 provided in the upper part of the first fluidized bed reactor 11. The gas is provided outside the first fluidized bed reactor 11 through a gas outlet provided in the upper part of the first fluidized bed reactor 11.
Unreacted gaseous olefin, saturated aliphatic hydrocarbon, and the like discharged from the first fluidized bed reactor 11 are cooled by a heat exchanger (cooling device) 14 through a circulation line 16 and supplied to a supply line. 12 and is continuously supplied again into the fluidized bed 18 in the first fluidized bed reactor 11 by the blower 13. In the heat exchanger 14, the circulating gas is usually cooled to a temperature near the dew point of the gas. The dew point is the temperature at which liquid condensate begins to form in the gas. When the circulating gas is cooled to a temperature below the dew point and supplied into the fluidized bed 18, the heat of reaction can be removed by the latent heat of vaporization of the liquid condensate, and the heat removal efficiency in the fluidized bed 18 can be improved. When circulating the circulating gas to the first fluidized bed reactor 11, a part of the circulating gas may be purged from any place in the circulation line 16.
[0032]
On the other hand, in the second fluidized bed reactor 21, the polymer particles extracted from the first fluidized bed reactor 11 from the extraction line 30 through the solid-gas separation vessels 31 and 32 are transferred to the transport line 25. Sent through. The transfer line 25 branches from the supply line 22, and the other end is connected to the upper side of the second fluidized bed reactor 21, and the gas containing olefin and saturated aliphatic hydrocarbon sent from the supply line 22 is received. The pressure is raised by a pressure raising means such as a centrifugal blower 41, and the polymer particles extracted from the first fluidized bed reactor 11 are transported along with the gas and introduced into the second fluidized bed reactor 21. It is supposed to be. Further, new gaseous olefin (polymerization monomer) and saturated aliphatic hydrocarbon are supplied from the supply line 22 through the blower 23 to the second fluidized bed reactor 21 by the transfer line 25, and as fluidized gas. It is supplied from the bottom of the second fluidized bed reactor 21. The second fluidized bed reactor 21 is not usually supplied with a new solid catalyst, but if necessary, a new solid catalyst is supplied via an arbitrary place of the fluidized bed reactor, for example, the transport line 25. May be.
[0033]
The fluidized gas supplied from the bottom of the second fluidized bed reactor 21 passes through a dispersion plate 27 made of a porous plate or the like disposed in the vicinity of the bottom of the second fluidized bed reactor 21 to the fluidized bed 28. It blows in and passes through the fluidized bed reactor 21 by being discharged from the upper part of the fluidized bed reactor 21. The solid particles (the polymer particles and the produced polymer) are maintained in a fluidized state by the gas flow of the gas passing through the fluidized bed reactor 21 to form a fluidized bed 28. At this time, a copolymerization reaction is performed in the fluidized bed 28.
[0034]
And the polymer particle obtained in the 2nd fluidized bed reactor 21 is continuously or intermittently extracted from the extraction line 40, and is supplied to the ligand decomposition process mentioned later.
Further, the unreacted gaseous olefin, saturated aliphatic hydrocarbon, and the like that have passed through the fluidized bed 28 are reduced in flow rate in the deceleration region 29 provided in the upper part of the second fluidized bed reactor 21. The gas is provided outside the second fluidized bed reactor 21 through a gas outlet provided at the top of the second fluidized bed reactor 21.
[0035]
Unreacted gaseous olefin, saturated aliphatic hydrocarbon, etc. discharged from the second fluidized bed reactor 21 are cooled by a heat exchanger (cooling device) 24 through a circulation line 26 and supplied to a supply line. 22, and continuously supplied again into the fluidized bed 28 in the second fluidized bed reactor 21 by the blower 23. In the heat exchanger 24, the circulating gas is usually cooled to a temperature near the dew point of the gas. When the circulating gas is cooled to a temperature below the dew point and supplied into the fluidized bed 28, the heat of reaction can be removed by the latent heat of vaporization of the liquid condensate, and the heat removal efficiency in the fluidized bed 28 can be improved. When circulating the circulating gas to the second fluidized bed reactor 21, a part of the circulating gas may be purged from any place in the circulation line 26.
[0036]
As described above, in the first fluidized bed reactor 11, the fluidized gas is circulated at a flow rate that can maintain the fluidized bed 18 in a fluidized state, and in the second fluidized bed reactor 21, the fluidized gas flows. The gasified gas is circulated at a flow rate that can maintain the fluidized bed 28 in a fluidized state.
Specifically, the amount of fluidized gas introduced from the bottom of the reactor from the supply lines 12 and 22 is about 3 Umf to about 50 Umf, preferably about 5 Umf, when the minimum fluidization rate of the fluidized bed is Umf. A flow rate of about 30 Umf is desirable. The fluidized bed can also be stirred mechanically, for example, by using various types of stirrers such as a squid type stirrer, a screw type stirrer, and a ribbon type stirrer.
[0037]
The multi-stage gas phase polymerization apparatus in which two fluidized bed reactors, that is, the first fluidized bed reactor 11 and the second fluidized bed reactor 21 are connected in series has been described. A multi-stage gas phase polymerization apparatus having a vessel can be similarly configured.
In the present invention, in the fluidized bed maintained in a fluidized state as described above, the polymerization monomer supplied into the reactor, that is, at least one olefin selected from ethylene and an α-olefin having 3 to 20 carbon atoms is polymerized. I am letting.
[0038]
In the present invention, polyenes and the like may be copolymerized with the olefin as necessary, for example, conjugated dienes such as butadiene and isoprene, 1,4-hexadiene, dicyclopentadiene, 5-vinyl-2-norbornene. Non-conjugated dienes such as can be copolymerized.
In the polymerization step, the supply amount of each monomer when copolymerizing two or more monomers selected from ethylene and an α-olefin having 3 to 20 carbon atoms is not particularly limited, but for example, ethylene and 2 to 2 carbon atoms. When 20 α-olefins are copolymerized, they are usually supplied in an amount of 0.015 to 0.15 mol, preferably 0.02 to 0.08 mol, per mol of ethylene.
[0039]
In the present invention, the polymerization reaction is carried out by introducing a saturated aliphatic hydrocarbon in a gas-liquid mixed state together with the polymerization monomer from the bottom of the reactor. Specific examples of such saturated aliphatic hydrocarbons include ethane, propane, n-butane, i-butane, n-pentane, i-pentane, hexane, heptane, octane, nonane, decane and 2,2-dimethyl. Propane, 2,2-dimethylbutane, 2,3-dimethylbutane, 2,2,3-trimethylbutane, 2-methylpentane, 3-methylpentane, 2,2-dimethylpentane, 3,3-dimethylpentane, 2 , 3-dimethylpentane, 2,4-dimethylpentane, 2-methylhexane, 3-methylhexane, 4-methylhexane, 2,3-dimethylhexane, cyclopentane, cyclohexane, methylcyclopentane, dimethylcyclopentane, etc. A C2-C10 saturated aliphatic hydrocarbon is mentioned. Among these, those having 3 to 8 carbon atoms are preferable.
[0040]
In the present invention, two or more kinds of saturated aliphatic hydrocarbons are used, at least one kind of saturated aliphatic hydrocarbon is introduced into the polymerizer in a gas-liquid mixed state, and the other saturated aliphatic hydrocarbons are gaseous. It may be introduced into the polymerization vessel. In this case, ethane, propane, n-butane, i-butane, i-pentane, n-pentane, hexane and the like are preferable as the saturated aliphatic hydrocarbon introduced into the reactor in a gaseous state, and these are used in combination. May be.
[0041]
Here, the gaseous saturated aliphatic hydrocarbon is a substance in which substantially all of the saturated aliphatic hydrocarbon is present as a gas phase. Specifically, 99% or more of 100% of all saturated aliphatic hydrocarbons are present. What exists as a gas phase, that is, a vapor fraction of 0.99 or more. This gas phase is present in the vapor-liquid equilibrium constant K according to the Soave-Redlich-Kwong method shown in Chem. Eng. Sci., 27, 1197 (1972)._iCan be obtained from
[0042]
Further, the saturated aliphatic hydrocarbon introduced into the reactor in a gas-liquid mixed state has a boiling point higher than that of the saturated aliphatic hydrocarbon introduced into the reactor in a gaseous state, and is cooled by a heat exchanger or the like. One that is easy to condense is selected. As the saturated aliphatic hydrocarbon, for example, i-pentane, n-pentane, hexane, heptane and the like are preferable, and these may be used in combination.
[0043]
In the present invention, when a saturated aliphatic hydrocarbon introduced in a gas-liquid mixed state and a saturated aliphatic hydrocarbon introduced in a gaseous state are used in combination, ethane and i-pentane are combined, or ethane and It is preferable to use hexane in combination.
The composition of the gas discharged from the reactor (that is, the gas composition of the fluidized bed reaction system) varies depending on the number of carbon atoms of the saturated aliphatic hydrocarbon, the polymerization temperature, the flow rate of the fluidizing gas, etc. It is desirable that the concentration of the saturated aliphatic hydrocarbon is usually 2 to 30 mol%, preferably about 5 to 20 mol%.
[0044]
When a saturated aliphatic hydrocarbon introduced in a gas-liquid mixed state and a saturated aliphatic hydrocarbon introduced in a gaseous state are used in combination, the concentration in the exhaust gas (saturated fat introduced in a gaseous state) Group hydrocarbon) / (saturated aliphatic hydrocarbon introduced in a gas-liquid mixed state) is preferably 60 to 100% by weight.
Saturated aliphatic hydrocarbons are usually introduced into the reactor from the feed line through the feed port at the bottom of the reactor together with the polymerization monomer as described above, but are replenished from any one place in the reactor or from different places. May be.
[0045]
In the fluidized bed, the polymerization of at least one olefin selected from ethylene and an α-olefin having 3 to 20 carbon atoms performed in the presence of a saturated aliphatic hydrocarbon is carried out by the type and ratio of the olefin to be polymerized, saturated fat The polymerization pressure is usually 0.1 to 10 MPa, preferably 0.2 to 4 MPa, and the polymerization temperature is usually 20 to 130 ° C., preferably 50 It is desirable that the reaction be performed at ˜120 ° C., more preferably at 70 to 110 ° C.
[0046]
The copolymerization can be carried out in the presence of a molecular weight regulator such as hydrogen, if necessary, and can be supplied from any place in the reactor.
The saturated aliphatic hydrocarbon as described above is a non-polymerizable hydrocarbon, and is not consumed by polymerization once supplied to the reactor, and is usually extracted from the discharge line together with unreacted polymerization monomers, It is circulated to the reactor as a fluidizing gas.
[0047]
Specifically, this exhaust gas may contain a saturated aliphatic hydrocarbon in a total amount of 0.8 to 80 mol%, but it varies depending on the number of carbon atoms of the saturated aliphatic hydrocarbon. The gas discharged from the reactor is usually led to a heat exchanger and cooled, and after the heat of polymerization is removed, it is circulated from the supply port to the reactor as a circulating gas. At this time, the saturated aliphatic hydrocarbon cooled in the heat exchanger is circulated to the reaction system in a gas-liquid mixed state. When the exhaust gas is circulated through the reactor in this way, a part of the exhaust gas may be purged.
[0048]
In the present invention, the molecular weight of the resulting olefin polymer can be adjusted by changing the polymerization conditions such as the polymerization temperature, or can be adjusted by controlling the amount of hydrogen (molecular weight regulator) used. it can.
At least one selected from ethylene and an α-olefin having 3 to 20 carbon atoms by introducing a gaseous saturated aliphatic hydrocarbon and a saturated aliphatic hydrocarbon in a gas-liquid mixed state into the reactor as described above. A kind of olefin is polymerized, and a low molecular weight component in the produced polymer is removed by a saturated aliphatic hydrocarbon, so that a polymer having very few n-decane soluble components can be obtained. Further, the polymerization heat of the fluidized bed can be removed by the latent heat of evaporation of the saturated aliphatic hydrocarbon introduced in the gas-liquid mixed state.
[0049]
In the present invention, the polymerization as described above can be carried out using a wide variety of known catalysts for ethylene polymerization such as Ziegler type titanium catalyst, Philip type chromium oxide catalyst, metallocene catalyst, etc. The olefin polymer is obtained when a metallocene catalyst is used. Specifically, the metallocene catalyst preferably used in the present invention is, for example,
(A) a metallocene compound of a transition metal selected from Group IVB of the periodic table,
and
(B) (B-1) Organoaluminum oxy compound,
(B-2) an organoaluminum compound, and
(B-3) Is it a compound that reacts with the metallocene compound (A) to form an ion pair?
At least one compound selected from the group consisting of:
[0050]
((A) metallocene compound)
The metallocene compound (A) of a transition metal selected from Group IVB of the periodic table is specifically represented by the following formula (i).
ML_x      ... (i)
Wherein M is a transition metal selected from Zr, Ti, Hf, V, Nb, Ta and Cr, L is a ligand coordinated to the transition metal, and at least one L is cyclopentadi L is a ligand having an enyl skeleton, and L other than the ligand having a cyclopentadienyl skeleton is a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group, an aryloxy group, a trialkylsilyl group Group or SO_ThreeR is a R group (where R is a hydrocarbon group having 1 to 8 carbon atoms which may have a substituent such as halogen), and x is a valence of the transition metal. )
Examples of the ligand having a cyclopentadienyl skeleton include cyclopentadienyl group, methylcyclopentadienyl group, dimethylcyclopentadienyl group, trimethylcyclopentadienyl group, tetramethylcyclopentadienyl group, penta Methylcyclopentadienyl group, ethylcyclopentadienyl group, methylethylcyclopentadienyl group, propylcyclopentadienyl group, methylpropylcyclopentadienyl group, butylcyclopentadienyl group, methylbutylcyclopentadienyl And an alkyl-substituted cyclopentadienyl group such as hexylcyclopentadienyl group or indenyl group, 4,5,6,7-tetrahydroindenyl group, fluorenyl group and the like. These groups may be substituted with a halogen atom, a trialkylsilyl group or the like.
[0051]
Of these, an alkyl-substituted cyclopentadienyl group is particularly preferable.
Specific examples of the ligand other than the ligand having a cyclopentadienyl skeleton include halogen, fluorine, chlorine, bromine, iodine and the like, and the hydrocarbon group having 1 to 12 carbon atoms is a methyl group. Alkyl groups such as ethyl group, propyl group, isopropyl group and butyl group, cycloalkyl groups such as cyclopentyl group and cyclohexyl group, aryl groups such as phenyl group and tolyl group, aralkyl groups such as benzyl group and neophyll group, etc. Examples of the alkoxy group include a methoxy group, an ethoxy group, and a butoxy group. Examples of the aryloxy group include a phenoxy group._ThreeExamples of the R group include a p-toluenesulfonate group, a methanesulfonate group, and a trifluoromethanesulfonate group.
[0052]
When the compound represented by the above general formula contains two or more groups having a cyclopentadienyl skeleton, the two groups having a cyclopentadienyl skeleton are alkylene groups such as ethylene and propylene, isopropyl It may be bonded via a substituted alkylene group such as lidene or diphenylmethylene, a silylene group or a dimethylsilylene group, a substituted silylene group such as a diphenylsilylene group or a methylphenylsilylene group.
[0053]
The metallocene compound containing a ligand having such a cyclopentadienyl skeleton is more specifically represented by the following formula (ii) when the valence of the transition metal is 4, for example.
R² _kR^Three _lR^Four _mR^Five _nM (ii)
Wherein M is the transition metal and R²Is a group (ligand) having a cyclopentadienyl skeleton, and R^Three, R^FourAnd R^FiveIs a group having a cyclopentadienyl skeleton or another group as described above, k is an integer of 1 or more, and k + l + m + n = 4. )
In the present invention, this formula R² _kR^Three _lR^Four _mR^Five _nIn M, R², R^Three, R^FourAnd R^FiveAt least two of them, eg R²And R^ThreeHowever, a metallocene compound which is a group (ligand) having a cyclopentadienyl skeleton is preferably used. These groups having a cyclopentadienyl skeleton may be bonded via an alkylene group, a substituted alkylene group, a silylene group, a substituted silylene group, or the like.
[0054]
Specific examples of the metallocene compounds as described above include, when M is zirconium, bis (cyclopentadienyl) zirconium dichloride, bis (cyclopentadienyl) zirconium dibromide, bis (cyclopentadienyl) dimethylzirconium, Bis (cyclopentadienyl) diphenylzirconium, bis (cyclopentadienyl) dibenzylzirconium, bis (cyclopentadienyl) zirconium bis (methanesulfonate), bis (cyclopentadienyl) zirconium bis (p-toluenesulfo Nate), bis (cyclopentadienyl) zirconium bis (trifluoromethanesulfonate), bis (methylcyclopentadienyl) zirconium dichloride, bis (dimethylcyclopentadienyl) zirconium dichloride Bis (ethylcyclopentadienyl) zirconium dichloride, bis (methylethylcyclopentadienyl) zirconium dichloride, bis (propylcyclopentadienyl) zirconium dichloride, bis (methylpropylcyclopentadienyl) zirconium dichloride, bis (butyl Cyclopentadienyl) zirconium dichloride, bis (methylbutylcyclopentadienyl) zirconium dichloride, bis (trimethylcyclopentadienyl) zirconium dichloride, bis (indenyl) zirconium dichloride, bis (indenyl) zirconium dibromide, bis (4, 5,6,7-tetrahydroindenyl) zirconium dichloride, bis (fluorenyl) zirconium dichloride, ethylenebis (indenyl) zirconium dichloride , Ethylenebis (indenyl) zirconium dibromide, ethylenebis (indenyl) dimethylzirconium, isopropylidene (cyclopentadienyl-fluorenyl) zirconium dichloride, isopropylidene (cyclopentadienyl-methylcyclopentadienyl) zirconium dichloride, dimethyl Silylenebis (cyclopentadienyl) zirconium dichloride, dimethylsilylenebis (methylcyclopentadienyl) zirconium dichloride, dimethylsilylenebis (dimethylcyclopentadienyl) zirconium dichloride, dimethylsilylenebis (indenyl) zirconium dichloride, dimethylsilylenebis ( 2-methylindenyl) zirconium dichloride, dimethylsilylenebis (2-methyl-4-isopropylindenyl) Zirconium dichloride, dimethylsilylene (cyclopentadienyl - fluorenyl) zirconium dichloride, diphenylsilylene bis (indenyl) zirconium dichloride, and the like methylphenyl (indenyl) zirconium dichloride.
[0055]
In the above examples, the disubstituted product of the cyclopentadienyl ring includes 1,2- and 1,3-substituted products, and the trisubstituted product includes 1,2,3- and 1,2,4-substituted products. . Alkyl groups such as propyl and butyl include isomers such as n-, i-, sec- and tert-.
Further, in the zirconium metallocene compound as described above, a compound in which zirconium is replaced with titanium, hafnium, vanadium, niobium, tantalum, or chromium can also be exemplified.
[0056]
In the present invention, a zirconium metallocene compound having a ligand containing at least two cyclopentadienyl skeletons is preferably used as the metallocene compound (A).
These metallocene compounds (A) can be used singly or in combination of two or more.
[0057]
((B-1) Organoaluminum oxy compound)
(B-1) The organoaluminum oxy compound may be a conventionally known benzene-soluble aluminoxane, or a benzene-insoluble organoaluminum oxy compound as disclosed in JP-A-2-276807. Good.
[0058]
The aluminoxane may contain a small amount of an organometallic component. Further, after removing the solvent or the unreacted organoaluminum compound from the recovered aluminoxane solution by distillation, it may be used by re-dissolving in the solvent.
Specific examples of the organoaluminum compound used in the production of aluminoxane include those described later as the organoaluminum compound (B-2), and these can be used in combination of two or more.
[0059]
Of these, trialkylaluminum and tricycloalkylaluminum are particularly preferred.
The benzene-insoluble organoaluminum oxy compound has an Al component dissolved in benzene at 60 ° C. of 10% or less, preferably 5% or less, particularly preferably 2% or less in terms of Al atom, and is insoluble or difficult to benzene. It is soluble.
[0060]
The solubility of such an organoaluminum oxy compound in benzene is determined by suspending the organoaluminum oxy compound corresponding to 100 milligrams of Al in 100 ml of benzene, mixing at 60 ° C. for 6 hours with stirring, and then attaching a jacket. Using a G-5 glass filter, hot filtration was performed at 60 ° C., and the solid portion separated on the filter was washed four times with 50 ml of benzene at 60 ° C., and the Al atoms present in the total filtrate were removed. It is determined by measuring the abundance (x mmol) (x%).
[0061]
The organoaluminum oxy compound (B-1) can be used alone or in combination of two or more.
((B-2) Organoaluminum compound)
The organoaluminum compound (B-2) is represented by the following general formula (iii), for example.
R¹ _nAlX_3-n      ... (iii)
(In formula (iii), R¹Is a C1-C12 hydrocarbon group, X is a halogen atom or a hydrogen atom, and n is 1-3. )
In the general formula (iii), R¹Is a hydrocarbon group having 1 to 12 carbon atoms, such as an alkyl group, a cycloalkyl group, or an aryl group. Specifically, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an isobutyl group, a pentyl group, Hexyl group, octyl group, cyclopentyl group, cyclohexyl group, phenyl group, tolyl group and the like.
[0062]
Specific examples of the organoaluminum compound (B-2) include trialkylaluminum such as trimethylaluminum, triethylaluminum, triisopropylaluminum, and triisobutylaluminum; alkenylaluminum such as isoprenylaluminum; dimethylaluminum chloride, Dialkylaluminum halides such as diethylaluminum chloride, diisopropylaluminum chloride, diisobutylaluminum chloride; alkylaluminum sesquichlorides such as methylaluminum sesquichloride, ethylaluminum sesquichloride, isopropylaluminum sesquichloride; methylaluminum dichloride, ethylaluminum dichloride, isopropylaluminum dichloride, etc. No al Kill aluminum dihalide; alkylaluminum hydrides such as diethylaluminum hydride and diisobutylaluminum hydride.
[0063]
As the organoaluminum compound (B-2), a compound represented by the following general formula (iv) can also be used.
R¹ _nAlY_3-n      … (Iv)
(In formula (iv), R¹Is the same as above, and Y is -OR.²Group, -OSiR^Three _ThreeGroup, -OAlR^Four ₂Group, -NR^Five ₂Group, -SiR⁶ _ThreeGroup or -N (R⁷AlR⁸ ₂A group, n is 1-2, R², R^Three, R^FourAnd R⁸Is a methyl group, an ethyl group, an isopropyl group, an isobutyl group, a cyclohexyl group, a phenyl group, and the like;^FiveIs a hydrogen atom, a methyl group, an ethyl group, an isopropyl group, a phenyl group, a trimethylsilyl group, etc., and R⁶And R⁷Is a methyl group, an ethyl group or the like. )
[0064]
Of these, trialkylaluminum is preferable, and triisobutylaluminum is particularly preferable.
The organoaluminum compound (B-2) can be used alone or in combination of two or more.
((B-3) Compound that reacts with metallocene compound (A) to form an ion pair)
Examples of the compound (B-3) that reacts with the metallocene compound (A) to form an ion pair include JP-A-1-501950, JP-A-1-502036, JP-A-3-179005, and JP-A-3. Examples include Lewis acids, ionic compounds, and carborane compounds described in JP-A Nos. -179006, JP-A-3-207703, JP-A-3-207704, and US-547718.
[0065]
Lewis acids include triphenylboron, tris (4-fluorophenyl) boron, tris (p-tolyl) boron, tris (o-tolyl) boron, tris (3,5-dimethylphenyl) boron, tris (pentafluorophenyl) ) Boron, MgCl₂, Al₂O_Three, SiO₂-Al₂O_ThreeEtc.
Examples of ionic compounds include triphenylcarbenium tetrakis (pentafluorophenyl) borate, tri-n-butylammonium tetrakis (pentafluorophenyl) borate, N, N-dimethylanilinium tetrakis (pentafluorophenyl) borate, ferrocenium tetra (Pentafluorophenyl) borate and the like.
[0066]
The carborane compounds include dodecaborane, 1-carbaundecaborane, bis n-butylammonium (1-carbedodeca) borate, tri-n-butylammonium (7,8-dicarboundeca) borate, tri-n-butylammonium (trideca Hydride-7-carbaoundeca) borate and the like.
These can be used alone or in combination of two or more.
[0067]
In the present invention, as the cocatalyst component (B), at least one compound selected from the above components (B-1), (B-2) and (B-3) is used, and these are appropriately combined. Can also be used. Among these, it is desirable to use at least (B-1) or (B-3) as the cocatalyst component (B).
In the present invention, it is preferable to use a catalyst containing the metallocene catalyst component and the cocatalyst component as described above, but these catalyst components are usually used as a carrier-supported catalyst (solid catalyst) by contacting with a particulate carrier compound. Is preferred.
[0068]
As the carrier compound, a granular or fine particle solid having a particle size of 10 to 300 μm, preferably 20 to 200 μm is used. The specific surface area of this carrier is usually 50 to 1000 m.²/ G, and the pore volume is 0.3 to 2.5 cm.^Three/ G is desirable.
As such a carrier, a porous inorganic oxide is preferably used, specifically, SiO.₂, Al₂O_Three, MgO, ZrO₂TiO₂, B₂O_Three, CaO, ZnO, BaO, ThO₂Or mixtures thereof, such as SiO₂-MgO, SiO₂-Al₂O_Three, SiO₂-TiO₂, SiO₂-V₂O_Five, SiO₂-Cr₂O_Three, SiO₂-TiO₂-MgO or the like is used. Among these, SiO₂And / or Al₂O_ThreeThe main component is preferred.
[0069]
The inorganic oxide contains a small amount of Na₂CO_Three, K₂CO_Three, CaCO_Three, MgCO_Three, Na₂SO_Four, Al₂(SO_Four)_Three, BaSO_Four, KNO_Three, Mg (NO_Three)₂, Al (NO_Three)_Three, Na₂O, K₂O, Li₂Carbonate such as O, sulfate, nitrate, and oxide component may be contained.
An organic compound can also be used as the carrier. For example, a (co) polymer produced mainly from an olefin having 2 to 14 carbon atoms such as ethylene, propylene, 1-butene, 4-methyl-1-pentene, etc. Alternatively, a polymer or copolymer produced mainly with vinylcyclohexane or styrene can be used.
[0070]
The contact between the carrier and each of the above components is usually carried out at a temperature of -50 to 150 ° C, preferably -20 to 120 ° C for 1 minute to 50 hours, preferably 10 minutes to 25 hours.
The solid catalyst prepared as described above has 5 × 10 5 metallocene compounds (A) as transition metal atoms per gram of support.^-6~ 5x10^-FourGram atoms, preferably 10^-Five~ 2x10^-FourIn an amount of gram atoms, component (B) is 10 as aluminum or boron atoms per gram of support.^-3~ 5x10^-2Gram atoms, preferably 2 × 10^-3~ 2x10^-2It is preferably supported in the amount of gram atoms.
[0071]
Furthermore, in the present invention, the solid catalyst as described above can be used in the polymerization as it is, but it can also be used after preliminarily polymerizing the olefin with this solid catalyst to form a prepolymerized catalyst.
In the present invention, the solid catalyst or the prepolymerized catalyst is transition metal / liter (polymerization volume), usually 10^-8-10^-3Gram atom / liter or even 10^-7-10^-FourIt is desirable to be used in an amount of gram atoms / liter.
[0072]
When using a prepolymerization catalyst, component (B) may or may not be used, but the atomic ratio of aluminum or boron in component (B) to transition metal in the polymerization system (Al or B / transition metal) 5 to 300, preferably 10 to 200, and more preferably 15 to 150.
The density (ASTM D 150 E) of the olefin polymer obtained as described above is preferably 0.865 to 0.930 g / cm.^Three, More preferably 0.880-0.930 g / cm^ThreeIt is.
[0073]
When the olefin polymer is an ethylene / α-olefin copolymer, the structural unit derived from ethylene is 87.0-97.6 mol%, preferably 90.0-96.8 mol%. Thus, it is desirable to contain a structural unit derived from an α-olefin having 3 to 10 carbon atoms in an amount of 13.0 to 2.4 mol%, preferably 10.0 to 3.2 mol%.
[0074]
The olefin polymer may contain units derived from polyenes in an amount of 10% by weight or less, preferably 5% by weight or less, particularly preferably 3% by weight or less.
(Ligand removal step)
The polymer particles ((co) polymer) extracted from the extraction line (10, 40) in the polymerization step as described above are sent to the ligand removal step, and the polymer particles in the polymer particle are removed in the ligand removal step. The ligand is removed.
[0075]
The ligand removal step (1) decomposes the ligand in the (co) polymer by bringing the (co) polymer obtained in the polymerization step as described above into contact with a ligand decomposing agent. A step (ligand decomposition step) and (2) a step of heating the (co) polymer brought into contact with the ligand decomposing agent to remove the decomposed ligand from the (co) polymer ( Decomposition ligand removal step).
[0076]
(Ligand decomposition agent)
Examples of the ligand decomposing agent used in the ligand decomposing step include water, oxygen, alcohol, alkylene oxide, peroxide and the like. Specifically, methanol, ethanol, propanol, isopropanol, butanol, pentanol, Monoalcohols such as hexanol, heptanol, octanol, cyclopentanol and cyclohexanol, alcohols having 10 or less carbon atoms such as dialcohols such as ethylene glycol; alkylenes such as ethylene oxide, propylene oxide, trimethylene oxide, tetrahydrofuran and tetrahydropyran Oxides; peroxides such as propylene peroxide and butene peroxide.
[0077]
Among these, water or an alcohol having 5 or less carbon atoms is preferable, and water is particularly preferable.
As a method of bringing the (co) polymer and the ligand decomposing agent into contact, for example, there is a method of bringing the (co) polymer and a gas stream containing the ligand decomposing agent into contact. In this case, for example, the (co) polymer powder is passed through the container while introducing a gas containing a ligand decomposing agent into the container.
[0078]
The average particle size of the (co) polymer powder when contacting with the ligand decomposing agent is usually in the range of 50 to 5,000 μm, preferably 80 to 3,000 μm, more preferably 100 to 2,000 μm. .
Examples of the gas containing the ligand decomposing agent include inert gases such as nitrogen gas and argon gas. The gas containing the ligand decomposing agent usually contains a vapor of the ligand decomposing agent. The content of the ligand decomposing agent in the ligand decomposing agent-containing gas is usually 0.1% by weight to 40% by weight, preferably 0.5% by weight to 20% by weight, particularly preferably 1% by weight to 10% by weight. % Range.
[0079]
The superficial velocity of the ligand decomposing agent-containing gas is usually 0.01 to 20 cm / second, preferably 0.1 to 10 cm / second, and particularly preferably 0.5 to 5 cm / second. The superficial velocity depends on the temperature and pressure of the gas containing the ligand decomposing agent at the gas outlet in the apparatus used when the (co) polymer and the ligand decomposing agent are brought into contact with each other. Calculated based on area.
[0080]
When the (co) polymer and the ligand decomposing agent are brought into contact with each other, the temperature when the crystallinity of the (co) polymer is 40% or more is usually higher than the crystallization temperature of the (co) polymer. And below the decomposition temperature of the (co) polymer, specifically in the range of 100 to 300 ° C, preferably 100 to 280 ° C. When the crystallinity of the (co) polymer is less than 40%, the melting point of the (co) polymer is −15 ° C. or more and less than the decomposition temperature of the (co) polymer. It is 300 degreeC, Preferably it is the range of 90-280 degreeC.
[0081]
The crystallinity of the (co) polymer (X_c) Is measured by the following method. That is, after preheating the (co) polymer at 190 ° C. for 7 minutes, pressurizing at 9.8 MPa for 2 minutes and then cooling under the conditions of 20 ° C. and 9.8 MPa to produce a 5 mm thick press sheet. About 5 mg of a test piece (sample) cut out from the press sheet is inserted into an aluminum pan. Using a DSC-II manufactured by PerkinElmer, an endothermic curve is obtained by measuring from room temperature to 150 ° C. at a heating rate of 10 ° C./min. Separately, the endothermic curve area of the sample is used to convert the endothermic curve of the sample into the heat of fusion. The point of 35 ° C. on the endothermic curve of the sample and the point at which the endothermic peak is not completely generated are connected to form a baseline. The value obtained by dividing the heat of fusion (A (J / g)) obtained by measurement by the heat of fusion (260 (J / g)) of 100% polyethylene crystal (X_c= A / 260) is the crystallinity.
[0082]
The pressure for contacting the (co) polymer with the ligand decomposing agent is usually 0.0001 to 0.6 MPa, preferably 0.001 to 0.35 MPa, and particularly preferably 0.01 to 0.25 MPa. It is a range. The contact time (residence time) is usually 1 minute to 3 hours, preferably 2 minutes to 2 hours, particularly preferably 5 minutes to 1 hour.
By contacting the (co) polymer and the ligand decomposing agent as described above, the ligand can be decomposed, and the ligand having a high boiling point can be converted into a low boiling point compound. . Further, depending on the type of ligand, it may be brominated without decomposition.
[0083]
Next, the (co) polymer brought into contact with the ligand decomposing agent is heated to remove the decomposed ligand in the (co) polymer. Examples of a method for removing the decomposed ligand by heating the (co) polymer brought into contact with the ligand decomposing agent include the following methods.
(1) A method of heating a (co) polymer under an inert gas flow using a dryer such as a rotary dryer, belt dryer, flash dryer, spray dryer or paddle dryer.
(2) A method of heating and melting a (co) polymer using a single-screw or twin-screw extruder.
[0084]
When the method (2) is employed, the heated and melted (co) polymer may be pelletized and further subjected to any one of the following steps (2-1) to (2-3).
(2-1) The step of bringing the pellet into contact with hot water
(2-2) Contacting the pellet with water vapor
(2-3) A step of heating the pellets under a pressure of 0.001 to 0.098 MPa.
In carrying out the method (1), the heating temperature of the (co) polymer is usually the crystallization temperature of the (co) polymer when the crystallinity of the (co) polymer is 40% or more. Above and below the decomposition temperature of the (co) polymer, or above the crystallization temperature of the (co) polymer and below the melting point of the (co) polymer, specifically 100 to 300 ° C., preferably 100 to The range is 280 ° C.
[0085]
When the crystallinity of the (co) polymer is less than 40%, the melting point of the (co) polymer is -15 ° C. or more and less than the decomposition temperature of the (co) polymer, or the melting point of the (co) polymer. It is −15 ° C. or higher and below the melting point of the (co) polymer, specifically 85 to 300 ° C., preferably 90 to 280 ° C.
The pressure is usually in the range of 0.0001 to 0.6 MPa, preferably 0.001 to 0.35 MPa, particularly preferably 0.01 to 0.25 MPa. The heating time (residence time) is usually 1 minute to 3 hours, preferably 2 minutes to 2 hours, particularly preferably 5 minutes to 1 hour.
[0086]
Examples of the inert gas include nitrogen gas, helium gas, and argon gas. The gas flow rate in the dryer is usually in the range of 0.01 to 20 cm / second, preferably 0.1 to 10 cm / second, particularly preferably 0.5 to 5 cm / second.
In carrying out the method (2), the heating temperature of the (co) polymer is the same as the method (1). In the present invention, in the decomposition ligand removal step, when heating at a temperature equal to or higher than the melting point of the (co) polymer and lower than the decomposition temperature, it is preferable to heat the (co) polymer while applying a shearing force, As a method for applying a shear force to the (co) polymer, there is a method using a paddle dryer, a single screw or a twin screw extruder, or the like.
[0087]
In the present invention, when the method (2) is adopted, the heat-melted (co) polymer is pelletized, and then any one of the following steps (2-1) to (2-3) is performed. May be.
The apparatus that can be used for carrying out the process (2-1) includes a countercurrent extraction tower, a storage tank having a stirring device, a multistage horizontal extraction tank, etc., and the processes (2-2) and (2-3). Examples of devices that can be used when performing the above are silos and hoppers.
[0088]
In performing the step (2-1), the temperature of the hot water is 35 to 200 ° C., preferably 40 to 180 ° C., particularly preferably 45 to 150 ° C., and the contact time is 1 to 900 minutes, preferably Is in the range of 5 to 600 minutes, particularly preferably 10 to 360 minutes.
In the step (2-2), the water vapor-containing gas and the (co) polymer are brought into contact in the same manner as in the ligand decomposition step. Examples of the gas containing water vapor include the same inert gas and air as described above.
[0089]
The temperature at which the (co) polymer is brought into contact with the water vapor-containing gas is usually equal to or higher than the crystallization temperature of the (co) polymer when the crystallinity of the (co) polymer is 40% or more, and It is below the decomposition temperature of the (co) polymer, or above the crystallization temperature of the (co) polymer and below the melting point of the (co) polymer, specifically 100 to 300 ° C., preferably 100 to 280 ° C. Range.
[0090]
When the crystallinity of the (co) polymer is less than 40%, the melting point of the (co) polymer is -15 ° C. or more and less than the decomposition temperature of the (co) polymer, or the melting point of the (co) polymer. It is −15 ° C. or higher and below the melting point of the (co) polymer, specifically 85 to 300 ° C., preferably 90 to 280 ° C.
The pressure is usually in the range of 0.0001 to 0.6 MPa, preferably 0.001 to 0.35 MPa, particularly preferably 0.01 to 0.25 MPa. The water vapor content in the water vapor-containing gas is usually in the range of 0.1 wt% to 40 wt%, preferably 0.5 wt% to 20 wt%, particularly preferably 1 wt% to 10 wt%.
[0091]
The superficial velocity of the water vapor-containing gas is usually 0.01 to 20 cm / second, preferably 0.1 to 10 cm / second, particularly preferably 0.5 to 5 cm / second. The contact time (residence time) is usually 0.5 to 30 hours, preferably 1 to 24 hours, particularly preferably 2 to 20 hours.
In carrying out the step (2-3), the pressure is in the range of 0.001 to 0.100 MPa, preferably 0.007 to 0.098 MPa, particularly preferably 0.01 to 0.07 MPa, and the temperature is 35. It is -200 degreeC, Preferably it is 40-180 degreeC, Most preferably, it is 45-150 degreeC. The heating time is 0.5 to 30 hours, preferably 1 to 24 hours, particularly preferably 2 to 20 hours.
[0092]
The average particle diameter of the (co) polymer pellets when the steps (2-1) to (2-3) are performed is usually in the range of 1 to 30 mm, preferably 3 to 20 mm, more preferably 5 to 15 mm. It is desirable to be.
More specifically, the ligand removal step of the (co) polymer can be performed by a step as shown in FIG. 3 or FIG. 4, for example. FIG. 3 is an explanatory diagram showing an example of the ligand removing step, and FIG. 4 is an explanatory diagram showing another example of the ligand removing step. The ligand decomposition step is performed in the silo indicated by 51 in the drawing, and the decomposition ligand removal step is performed in the extruder indicated by 52, the silo indicated by 54, and the dryer indicated by 57 in the drawing.
[0093]
Hereinafter, an example in which water (water vapor) is used as a coordination decomposition agent will be described. In the step shown in FIG. 3, the (co) polymer powder is continuously supplied from the powder supply pipe 61 to the silo 51. In the silo 51, an inert gas containing water vapor is supplied to the silo 51 from a gas supply pipe 62 disposed in the lower part. As a result, the powder of the (co) polymer comes into contact with water vapor, and the ligand contained in the (co) polymer is decomposed. The inert gas containing water vapor supplied to the silo 51 is discharged out of the silo 51 from the gas discharge pipe 64.
[0094]
The (co) polymer powder in contact with the water vapor is discharged out of the silo 51 from the powder discharge pipe 63 and then supplied to the extruder 52. The (co) polymer heated and melted by the extruder 52 is cooled with water and pelletized. Thereby, a part of the decomposed ligand contained in the (co) polymer is removed. The obtained (co) polymer pellets are supplied together with water through the line 65 to the dehydrator 53, and the dehydrated (co) polymer pellets are supplied to the silo 54 through the pellet supply pipe 67. The water separated by the dehydrator 53 passes through the circulation line 66 and is reused as cooling water. In the figure, 55 is a water storage tank and 56 is a pump.
[0095]
In the silo 54, an inert gas containing water vapor is supplied to the silo 54 from a gas supply pipe 68 disposed in the lower part. As a result, the (co) polymer pellets and water vapor come into contact with each other, and the decomposed ligand contained in the (co) polymer is further removed. The inert gas containing water vapor supplied to the silo 54 is discharged out of the silo 54 from the gas discharge pipe 70. The pellet of the (co) polymer from which the decomposed ligand has been removed is discharged from the pellet discharge pipe 69.
[0096]
In the step shown in FIG. 4, as in the step shown in FIG. 3, the (co) polymer powder and the inert gas containing water vapor contact in the silo 51, and the coordination contained in the (co) polymer. Child is disassembled. The (co) polymer powder in contact with the water vapor is discharged out of the silo 51 from the powder discharge pipe 63 and then supplied to the dryer 57. In FIG. 4, the dryer 57 is a belt dryer, but is not limited to this.
[0097]
In the dryer 57, the heated inert gas is supplied from the gas supply pipe 71, and the (co) polymer powder is heated and contacts the inert gas. Thereby, the decomposed ligand contained in the (co) polymer is removed. The inert gas supplied to the dryer 57 is discharged from the gas discharge pipe 72.
The (co) polymer powder from which the decomposed ligand has been removed is supplied to the crusher 58 through the line 73, crushed and then discharged from the discharge pipe 74.
[0098]
In the ligand removal step, the ligand having the cyclopentadienyl skeleton remaining in the (co) polymer is decomposed and removed from the (co) polymer obtained in the polymerization step, so that molding is performed. Sometimes polyolefins with less odor generation can be obtained.
[0099]
【The invention's effect】
The olefin polymer of the present invention has a low content of low molecular weight components such as oligomers and ligands having a cyclopentadienyl skeleton, which are components that generate odors and components that change taste. When used in food applications, the content of components that generate odors and components that change the taste is small, so that the flavor of the food is rarely impaired.
[0100]
The method for producing an olefin polymer of the present invention comprises a component that generates odor, a component that changes taste, a low molecular weight component such as an oligomer, and a ligand content having a cyclopentadienyl skeleton. Can produce an olefin polymer with a low cost and high productivity.
[0101]
【Example】
EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.
[0102]
[Example 1]
(Preparation of solid catalyst component)
Silica (SiO2) dried at 250 ° C. for 10 hours₂) 10 kg was suspended in 154 liters of toluene and then cooled to 0 ° C. To this suspension, 50.5 liters of a toluene solution of methylaluminoxane (Al = 1.52 mol / liter) was added dropwise over 1 hour while maintaining the temperature of the suspension at 0 to 5 ° C. After maintaining at 0 ° C. for 30 minutes, the temperature was raised to 95 ° C. over 1.5 hours and maintained at 95 ° C. for 4 hours.
[0103]
Thereafter, the temperature was lowered to 60 ° C., and the supernatant was removed by decantation. The solid catalyst component thus obtained was washed twice with toluene and then resuspended in 100 liters of toluene to a total volume of 160 liters.
To the obtained suspension, 22.0 liters of a toluene solution of bis (1,3-n-butylmethylcyclopentadienyl) zirconium dichloride (Zr = 25.7 mmol / liter) was added at 80 ° C. over 30 minutes. The solution was added dropwise and kept at 80 ° C. for 2 hours. Thereafter, the supernatant was removed and washed twice with hexane to obtain a solid catalyst component containing 3.2 mg of zirconium per 1 g of silica.
[0104]
(Preliminary polymerization of solid catalyst components)
Into a 350 liter reactor sufficiently purged with nitrogen, 7.0 kg of the above solid catalyst component was charged, and hexane was charged to obtain a hexane suspension having a total volume of 285 liters. After cooling the system to 10 ° C, ethylene was flowed at 8 Nm.^Three/ Hr for 5 minutes into a solid catalyst component hexane suspension. During this time, the temperature in the system was maintained at 10 to 15 ° C.
[0105]
After the supply of ethylene was temporarily stopped, 2.4 mol of triisobutylaluminum and 1.2 kg of 1-hexene were supplied to make the inside of the system a sealed system, and then the supply of ethylene was resumed, with a flow rate of 8 Nm3 / hr. After supplying for 1 minute, the flow rate is 2Nm^Three/ Hr, the pressure in the system is 0.8 kg / cm²-G. During this time, the system temperature rose to 35 ° C.
[0106]
Then, while controlling the temperature in the system to 32 to 35 ° C., ethylene was reduced to 4 Nm.^Three/ Hr was supplied for 3.5 hours. During this time, the pressure in the system is 0.7 to 0.8 kg / cm.²-Hold on G. Next, the system was purged with nitrogen, the supernatant was removed, and then washed twice with hexane. The supernatant liquid after preliminary polymerization was colorless and transparent.
As described above, a prepolymerized catalyst containing 3 g of the prepolymer per 1 g of the solid catalyst component was obtained. This prepolymerized catalyst (prepolymer) had an intrinsic viscosity [η] measured in decalin at 135 ° C. of 2.1 dl / g and a 1-hexene unit content of 4.8% by weight. The shape of the prepolymerized catalyst is good and the bulk density is 0.4 g / cm.^ThreeMet.
[0107]
(Gas phase polymerization)
Gas phase polymerization was performed using a continuous fluidized bed reactor as shown in FIG.
That is, the prepolymerized catalyst obtained as described above was continuously supplied in an amount of 54 g / hr, and ethylene and 1-hexene were continuously polymerized in the presence of isopentane. LLDPE).
[0108]
The polymerization conditions were a polymerization temperature of 70 ° C., a polymerization pressure of 1.7 MPa-G (gauge pressure), an ethylene partial pressure of 1.1 MPa, a superficial velocity of 0.80 m / s, and a gas in the reactor deceleration region (TOP gas). The test was performed under the condition of an isopentane concentration of 5 mol%. During this polymerization, the TOP gas has an average molecular weight of 31.4 g / mol and a density of 20.7 kg / m.^ThreeMet. The dew point of the TOP gas was 40.1 ° C., the temperature on the circulating gas outlet side of the heat exchanger was 62.3 ° C., and the condensate ratio on the circulating gas outlet side was 0% by weight.
[0109]
The TOP gas is a mixture of ethylene, nitrogen, hydrogen, 1-hexene and isopentane.
The LLDPE obtained as described above has a density (ASTM D1505) of 903 kg / m.^ThreeThe MFR (ASTM D1238) was 3.8 g / 10 min.
[0110]
(Ligand decomposition step)
Steam-containing nitrogen gas was introduced, and the LLDPE powder was passed through a silo having a pressure of 0.5 kPa-G and a temperature of 80 ° C. with a residence time of 5 minutes.
The weight ratio (water / PE) of water and polyethylene powder (PE) at this time is 0.001, and nitrogen gas (N₂) And polyethylene powder (PE) ratio (N₂(Nm^Three) / PE (kg)) was 0.004.
[0111]
(Decomposing ligand removal step)
The LLDPE powder that had undergone the ligand decomposition step was pelletized at an outlet temperature of 205 ° C. using a twin screw extruder. Thereafter, steam-containing air was introduced, and the LLDPE powder that had undergone the ligand decomposition step was passed through a silo that had a pressure of 0.5 kPa-G and a temperature of 80 ° C. in a residence time of 6 hours.
[0112]
At this time, the weight ratio (water / PE) of water vapor (water) and polyethylene pellets (PE) is 0.09, and the ratio of air (Air) to polyethylene pellets (PE) (Air (N-m^Three) / PE (kg)) was 0.14.
(Evaluation)
The LLDPE after the treatment as described above was evaluated for the residual ligand amount, the n-decane soluble content, and the odor. The results are shown in Table 1.
[0113]
In addition, evaluation of the odor of LLDPE after the said process was performed as follows.
A: None of the three evaluators felt odor.
○: One of the three evaluators felt odor. However, I did not feel a strong smell.
Δ: Among the three evaluators, there were a few who felt odor. However, I did not feel a strong smell.
[0114]
X: All three evaluators felt a strong odor.
[0115]
[Examples 2 to 4 and Comparative Examples 1 to 6]
In Example 1, the isopentane concentration in the polymerizer TOP gas, the average molecular weight in the polymerizer TOP gas, the density of the polymerizer gas, the gas temperature at the outlet side of the heat exchanger circulation gas, etc. were changed to the conditions shown in Table 1. Except that, LLDPE was obtained in the same manner as in Example 1.
[0116]
Table 1 shows the results of evaluating the ligand residual amount, n-decane soluble content and odor of the obtained LLDPE in the same manner as in Example 1.
[0117]
[Table 1]

[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a case where a polymerization process is performed in a single stage.
FIG. 2 is an explanatory diagram showing a case where a polymerization process is performed in two stages.
FIG. 3 is an explanatory diagram showing an example of a ligand removal step.
FIG. 4 is an explanatory diagram illustrating another example of a ligand removal step.
[Explanation of symbols]
10, 40 ... Extraction line
11, 21 ... Fluidized bed reactor
12, 22 ... Supply line
18, 28 ... Fluidized bed
51, 54 ... silos
52 ... Extruder
57… dryer

Claims (5)

Using a fluidized bed reactor, one or more olefins selected from ethylene and an α-olefin having 3 to 20 carbon atoms are (co) polymerized in the gas phase in the presence of a metallocene catalyst. A method for producing an olefin polymer, comprising:
A polymerization step of (co) polymerizing the olefin while allowing the saturated aliphatic hydrocarbon to be present in the fluidized bed reactor at a concentration of 5 to 30 mol%;
The obtained (co) polymer is brought into contact with a ligand decomposing agent which is water or an alcohol having 5 or less carbon atoms, and then the (co) polymer brought into contact with the ligand decomposing agent is heated. A method for producing an olefin polymer, comprising a ligand removal step.   An olefin having an n-decane soluble content of 10% by weight or less and a content of a ligand having a cyclopentadienyl skeleton of 5% by weight or less by the method for producing an olefin polymer according to claim 1. A method for producing an olefin polymer, comprising producing a polymer.   The olefin polymer according to claim 1 or 2, wherein the olefin polymer is a copolymer of ethylene and at least one α-olefin selected from α-olefins having 3 to 20 carbon atoms. A method for producing a polymer. The method for producing an olefin polymer according to any one of claims 1 to 3, wherein the density of the olefin polymer is 0.930 g / cm ³ or less. Metallocene catalyst
(A) a metallocene compound of a transition metal selected from Group IVB of the periodic table,
And (B) (B-1) an organoaluminum oxy compound,
2. (B-2) An organoaluminum compound and (B-3) at least one compound selected from compounds that react with the metallocene compound (A) to form an ion pair. The manufacturing method of the olefin polymer in any one of -4.

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