WO2002018459A1

WO2002018459A1 - Process for the production of copolymers or terpolymers with functionalized pendant groups

Info

Publication number: WO2002018459A1
Application number: PCT/US2001/023338
Authority: WO
Inventors: Gregory G. Hendrickson; Alphonzo G. Nelson; Ronald G. Abbott; Anne M. Balinsky
Original assignee: Chevron Phillips Chemical Company Lp
Priority date: 2000-08-29
Filing date: 2001-07-24
Publication date: 2002-03-07
Also published as: AU2001277149A1

Abstract

The present invention relates to a method of synthesizing a copolymer, comprising: providing a monomer, a comonomer, and a catalyst; reacting the monomer and the comonomer in the presence of the catalyst in a reactor, under conditions wherein the monomer is a liquid in which the comonomer is soluble, to yield a polymer comprising the monomer; and separating unreacted monomer and unreacted comonomer from the polymer, to yield the purified polymer. Preferably, the monomer is vinyl cyclopentene, 4-vinyl-1-cyclohexene, vinyl cycloheptene, or vinyl cyclooctene, and the comonomer is ethylene or styrene. The separating step can comprise heating the polymer; subjecting the polymer to vacuum flashing; passing the polymer through a thin film evaporator; stripping the polymer with N2 or steam; or any combination thereof. Further, the separated monomer and comonomer can be recycled to the providing step.

Description

PROCESSFORTHEPRODUCTIONOF COPOLYMERS ORTERPOLYMERS WITH

FUNCTIONALIZED PENDANT GROUPS

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to the field of polymer synthesis. More particularly, it concerns the solution polymerization of a monomer and a comonomer, followed by sequential devolatilization to remove unreacted monomer, comonomer, or other reactants from the product.

2. Description of Related Art

The polymerization of a monomer and a comonomer can be performed by combining the monomer and the comonomer under appropriate reaction conditions in any one of a number of phases. Commercially relevant polymerization is often performed in solution or in the gas phase. Solution polymerization involves dissolving the monomer and the comonomer in a mutual solvent. However, the solvent must later be removed from the polymer, and, if the solvent is an organic compound, such as toluene, extensive solvent removal is required. This is especially true if the polymer is intended for a food packaging use, such as an oxygen scavenging polymer in an oxygen scavenging packaging article.

Other forms of solution polymerization include emulsion polymerization (in wliich the monomer and the comonomer are present in an oil phase emulsified in an aqueous external phase) and suspension polymerization (in which the monomer and the comonomer are suspended in an aqueous solution by a suspending agent, such as poly vinyl alcohol). However, these latter forms of solution polymerization require more components, such as an oil and an emulsifier, or a suspending agent, which also must be removed from the polymer.

Therefore, it is desirable to have a solution polymerization method involving the addition of a minimal amount of solvent or other components.

Welborn et al., WO 88/04674, discloses a method for the synthesis of copolymers of ethylene and 4-vinyl-l-cyclohexene by solution polymerization. The solution polymerization process disclosed by Welborn et al. involves the use of hexane or toluene as the solvent (i.e. at least about 50 vol% of the reactor contents). Vidal, U.S. Patent No. 5,504,167, discloses a method for the free radical synthesis of copolymers of ethylene with a carboxylic acid, an ester, an anhydride, or a nitrilo derivative, by a continuous process involving 2-25 wt% of solvent comprising methanol.

Marshall et al., U.S. Patent No. 5,057,593, discloses a method for the free radical copolymerization of ethylene, carbon monoxide, and a carboxylic acid, an ester, an anhydride, or a nitrilo derivative, by a continuous process involving 2-20 wt% of solvent comprising acetone.

Hatch et al., U.S. Patent No. 5,028,674, discloses a method for the free radical synthesis of copolymers of ethylene with a carboxylic acid, an ester, or an anhydride, by a continuous process involving 2-25 wt%, preferably 5-20 wt%, of solvent comprising methanol.

Kawata et al., U.S. Patent No. 5,272,235, discloses a method for the synthesis of copolymers of ethylene and a cycloolefin, involving copolymerizing the ethylene and the cycloolefin in a hydrocarbon solvent or a liquid phase comprising the cycloolefin. The method also generates solid polyethylene as an impurity.

Echte et al., EP 54148, discloses a method for the free radical synthesis of copolymers of vinyl-aromatic compounds and ethylenically-unsaturated monomers.

Shimokawa et al., U.S. Patent No. 4,314,041 discloses a method for the graft copolymerization of a rubber with a mixture of vinyl-aromatic and vinyl cyanide compounds, wherein the mixture may be used to form a solution of the rubber.

Asada et al., JP 51140983 discloses a method for the polymerization of propylene, or the copolymerization of propylene with ethylene, in the liquid phase of propylene.

SUMMARY OF THE INVENTION

In one embodiment, the present invention relates to a method of synthesizing a copolymer, comprising: providing a monomer, a comonomer, and a catalyst; reacting the monomer and the comonomer in the presence of the catalyst in a reactor, under conditions wherein the monomer is a liquid in which the comonomer is soluble, to yield a polymer comprising the monomer and comonomer; and separating unreacted monomer and unreacted comonomer from the polymer, to yield the purified polymer.

The separating step can comprise heating the polymer to a temperature appropriate for degassing; subjecting the polymer to vacuum flashing; passing the polymer through a thin film evaporator; stripping the polymer with N₂ or steam; or any combination thereof. Further, the separated monomer and comonomer can be recycled to the providing step. The method has the advantage of not requiring the addition of a solvent. The monomer functions as a solvent for the other reactants. This provides cost savings, in that no further solvent is required and a solvent recovery step need not be performed. Environmental benefits may also be seen by not requiring a further solvent.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The monomer and comonomer can be any molecules from which it is desired to synthesize a polymer. Preferably, the monomer and comonomer each comprises an ethylenic group (defined as two carbon atoms covalently linked by a double bond) which, under the conditions described below, undergoes polymerization with the ethylenic group of another monomer molecule or comonomer molecule, to yield a polymer with a polyethylenic backbone.

It is also preferred that the monomer or comonomer comprises a pendant group comprising a benzylic or a cyclic olefinic group ("pendant group" is defined as a group that does not substantially participate in polymerization of the monomer or comonomer under the conditions described below). Such a group can be substituted or unsubstituted, and can be polycyclic. More preferably, the monomer or comonomer comprises a cyclic olefinic pendant group having the structure I:

wherein q_1? q₂, q₃, q₄, and r are independently selected from hydrogen, methyl, or ethyl; m is -(CH )_n-, wherein n is an integer from 0 to 4, inclusive.

Most preferably, n is 1 and qi, q₂, q , q₄, and r are each hydrogen; i.e. the cyclic olefinic group is a cyclohexenyl group. Also, the monomer is a compound that is liquid under conditions in which the reaction will take place. The monomer is chosen such that the comonomer is soluble in the monomer under reaction conditions. In other words, the reaction is a solution polymerization in which the monomer also functions as the solvent. This will be described in more detail below.

If an additional compound is present wliich is liquid under the reaction conditions and in which the comonomer is soluble, such as possibly toluene or benzene, among others, the additional compound can be present at any concentration. Such an additional compound can be a solvent for the catalyst or some other additive. However, such additional compound is not required in the present invention.

Preferred monomers include vinyl cycloolefins, such as vinyl cyclopentene, 4-vinyl-l- cyclohexene, vinyl cycloheptene, or vinyl cyclooctene. More preferably, the monomer is 4- vinyl-1-cyclohexene. Preferably, the comonomer is a vinyl compound, such as ethylene or styrene. More preferably, the comonomer is ethylene.

The catalyst can be any compound useful in catalyzing the polymerization of the monomer and the comonomer, and will vary depending on the monomer and comonomer, the mechanism of polymerization, and other parameters known to one of skill in the art. The catalyst can also comprise a cocatalyst. Catalyst systems that can be used include metallocenes, such as those disclosed by U.S. Patent Nos. 6,043,180; 5,863,853; 5,770,663; and Ziegler-Natta catalysts, such as those disclosed by U.S. Patent Nos. 5,488,022 and 5,994,256. The listed patents are hereby incorporated by reference. Exemplary Ziegler-Natta catalysts include TiCb and A1(C₂H5) Q; TiCk and A1(C₂H5)3; Ti salt/organomagnesium compound/silane systems supported on silica, alumina, or both; Examplary metallocenes include cyclopentadienylide catalyst systems using a metallocene complex, e.g. titanocene or zirconocene, and an alumoxane, such as methyl alumoxane (MAO) or modified methaluminoxane (MMAO). The alumoxane can be supported or unsupported. Metallocene catalyst systems, such as røc-en(Ind)₂ZrCl /MMAO (Ethylenebis(l-indenyl)zirconium dichloride/MMAO, CAS Registry No. 112243-78-4), r c-en(THInd)₂ZrCl₂/MMAO (Ethylenebis(tetrahydroindenyl)zircom^'um dichloride/MMAO, CAS Registry No. 112243-79- 5), or (C₅Me₄SiMe₂NBu^t)TiCl₂/MMAO (2,3,4,5-tetramethylcycloρentadienyl-l-dimethylsilyl- t-butylamido)titanium dichloride/MMAO, CAS Registry No. 135072-61-6) are preferred. Other catalysts known in the art may also prove effective and can be used. The catalyst may be made up with a solvent, if desired, which could be either the monomer or a separate solvent. Also, free radical initiators, such as benzoyl peroxide, can be used, and are within the scope of "catalyst" as that term is used in the claims. In addition to the monomer, the comonomer, and the catalyst, other compounds can be provided, such as process gases, e.g., hydrogen, nitrogen, or ethylene, among others. Other compounds that one of ordinary skill in the art would recognize to be useful in the method of the present invention can also be included.

If desired, the monomer, the comonomer, and the process gases, can be purified before the reacting step. Typical impurities that may be present in the monomer, comonomer, or process gas include water, oxygen, alcohols, ketones, polymerization inhibitors, oxidation inhibitors, CO, CO₂, acetylene, and H₂S, among others. Removal of impurities can be brought about by passing the monomer, the comonomer, or the process gas through or over a molecular sieve, alumina, a deoxo column, or a combination of the above, among other purification apparatus. The deoxo column can comprise a CuO or CuO/ZnO system (such as are commercially available as R 3-11 (BASF) or G-66B (Girdler)) for removal of O₂ and CO from ethylene or nitrogen. Oxygen and CO can be removed from hydrogen by a deoxo column comprising a noble metal catalyst.

Also, catalyst, unreacted monomer, or unreacted comonomer derived from the effluent of the reactor as will be described below can be returned to the providing step, if desired, and can be subjected to purification as described above, if desired.

Once the monomer, the comonomer, and the catalyst, as well as any further additives are provided and, if desired, purified, the monomer and comonomer are fed to a reactor. The catalyst and any further additives are also fed to the reactor. The feeds into the reactor can be added through separate lines or a single line. If one of the compounds is added in a gas phase, it is preferably sparged through the liquid phase. The order and rate of addition, and the concentration, of the various compounds are generally routine parameters, although variations in the order or rate may have an impact on the rate of the polymerization reaction or the yield thereof.

The reactor used can be any known in the art. By "reactor" is meant any vessel or vessels into which reactants can be introduced, from which products and unreacted reactants can be withdrawn, and in which the temperature, pressure, and composition (reactants and inerts) can be controlled. Any such vessel or vessels known in the art can be used. Multiple vessels can be arranged in series, in parallel, or a combination thereof. The layout of the reactor is a manner of routine experimentation to the skilled artisan. Preferably, the reactor is capable of continuous operation, although batch operation can also be undertaken. Preferably, the contents of the reactor can be agitated, such as by the use of a paddle rotor, sonication, or other techniques known in the art. It is also desirable that the reactor have temperature control capabilities, such as a jacket through which is circulated cold water or refrigerant, in order to remove heat generated by exothermic polymerization reactions.

The polymerization can occur by any technique known in the art, such as Ziegler-Natta polymerization or metallocene polymerization, among others. The copolymer formed from the reaction of the monomer and the comonomer will typically be a random copolymer, although a block copolymer may also be generated by the method of the present invention. The proportions of monomer and comonomer units in the copolymer will roughly depend on the proportions of the monomer and the comonomer added to the reactor, and the relative reactivity of the monomer and the comonomer in polymerization.

The reaction conditions can be selected to generate a polymer having a desired molecular weight range, a desired proportion of linearity or branched status, or other parameters known to one of ordinary skill in the art.

For a given pressure, the temperature can be any temperature at which the monomer is liquid and the monomer, comonomer, or polymer produced by the reaction do not degrade. Preferably, the temperature is between about 38°C (100°F) and about 93 °C (200°F), more preferably between about 60°C (140°F) and about 83°C (180°F). In one preferred embodiment, if the monomer is 4-vinyl-l-cyclohexene, the temperature can be about 60°C (140°F).

Preferably, the pressure is ambient pressure or higher, up to about 300 psi. For example, in one embodiment of the present invention, using a Zr-based catalyst and ethylene as comonomer in conjunction with hydrogen as a process gas, the partial pressure of the ethylene can be about 18 psig, and the hydrogen partial pressure can be about 5 psig. In one preferred embodiment, if the catalyst is Ti-based, the partial pressure of the ethylene can be about 100 psig, and the partial pressure of the hydrogen can be about 18 psig.

The present invention can also be used to produce a terpolymer of the monomer, the comonomer, and a second comonomer. The second comonomer can be within the definitions of "monomer" or "comonomer" given above. If a terpolymer is to be made according to the present invention, all references herein to "monomer" or "comonomer" should be construed to also refer to the second comonomer, as appropriate.

Once polymerization has progressed to a desired endpoint, or has been allowed to occur for a desired length of time, some or all of the polymer and some or all of any unreacted monomer or unreacted comonomer, is passed from the reactor as effluent. This can occur during either a continuous polymerization or a batch polymerization. After removal of the effluent from the reactor, monomer or comonomer is separated from the polymer. Separation can occur by any technique that can discriminate between the polymer and any monomer or comonomer that may be present. In one embodiment, the separating step comprises heating the polymer to a temperature below the boiling point or thermal decomposition point of the polymer but above the boiling point of the monomer or the comonomer. This will cause at least some of the monomer or comonomer present in the effluent to flash off into the overhead gas stream. One of ordinary skill in the art will recognize the boiling point is dependent on the pressure of the gas stream overhead, and that lowering the overhead pressure will reduce the temperature required to flash off the monomer or the comonomer. In one embodiment, wherein 4-vinyl-l-cyclohexene and ethylene are the monomer and the comonomer, maintaining an overhead pressure at or below 2 psia, while heating the mixture to at least about 50°C, is adequate.

In another embodiment, monomer or comonomer can be separated from the polymer by subjecting the polymer to vacuum flashing. One of ordinary skill in the art will recognize that volatile molecules will more readily leave the liquid phase under vacuum flashing than will less volatile molecules, such as the polymer. Vacuum flashing can be performed using an appropriate apparatus, including one or more vacuum flash separators.

The above embodiments can be performed together, either simultaneously or in sequence, preferably simultaneously.

In still another embodiment, the polymer can be passed through an evaporator, such as a wiped film evaporator, in order to remove monomer or comonomer. A wiped film evaporator is preferred over other forms of evaporators because it provides better temperature control and also the turning action of the wiped blades refreshes the polymer surface to maximize removal of monomer or comonomer. Any appropriate apparatus can be used.

Additionally, the polymer can be stripped with N₂ or steam, preferably under vacuum. Gas stripping can be performed using any appropriate apparatus.

Preferably, passing the polymer through an evaporator and gas stripping the polymer are performed together. Even more preferably, all four techniques of heating the polymer, vacuum flashing, passing through an evaporator, and gas stripping are performed. In all cases, the order of steps and the structure of the apparatus used can be varied as a matter of routine experimentation.

Alternatively, or in addition, the separating step can comprise solvent extraction, such as by the use of methanol, or supercritical fluid extraction, such as by the use of CO₂ or isobutane, following techniques known in the art. After the monomer and the comonomer have been separated from the polymer, the monomer, the comonomer, or both can be recycled to the reactor. By "recycled to the reactor" is meant that unreacted monomer or unreacted comonomer is fed from the separating apparatus to the reactor, either directly or through intermediate processing apparatus (e.g. to purify the monomer or comonomer, to add process gas, or for other reasons). Further purification can be performed during the recycling process, if desired.

After the separating step, the polymer can be used in the formation of a finished article, such as a packaging article, or can be stored in a form such as a film or pellets for eventual use.

The following examples are included to demonstrate preferred embodiments of the invention. It should be appreciated by those of skill in the art that the techniques disclosed in the examples which follow represent techniques discovered by the inventor to function well in the practice of the invention, and thus can be considered to constitute preferred modes for its practice. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the invention.

Example 1. Copolymerization of Ethylene and 4-vinyl-l-cyclohexene

Feed Purification Area

In the feed purification area, the monomer, 4-vinyl-l-cyclohexene (VCH), is unloaded from tank trucks to storage tanks where it is stored under nitrogen. VCH must be purified before it can be used in the reaction. This is accomplished using a single stage process where VCH passes over beds of molecular sieves and alumina to remove any water and polar impurities present such as alcohols. Upon completion of the purification, VCH is stored in a day tank, under nitrogen, before being fed to the reactor.

The process gases (ethylene, hydrogen and nitrogen) undergo a similar two-stage pretreatment process for oxygen and moisture removal. In the first stage, oxygen is removed in a deoxo reactor. For ethylene and nitrogen gases, a catalyst such as CuO/ZnO (Girdler G-66B) or CuO (BASF R 3-11) catalyst is used in the deoxo reactor for oxygen and carbon monoxide removal. The catalyst used in the hydrogen reactor is a noble metal catalyst for oxygen removal. In all three cases, the second step in the pretreatment involves drying the individual streams by passing over beds of molecular sieves and alumina before entering the polymerization reactor or other process areas. Catalyst Preparation Area

The catalyst preparation system consists of two vessels, one containing the catalyst and the second for the optional co-catalyst. Two chemical metering pumps regulate the flow of catalyst and, if applicable, co-catalyst from their respective vessels to a static mixer, where the two streams mix and form the active catalyst species immediately before entering the reactor.

Polymerization Reaction

In the proposed process, the co-polymerization of ethylene and VCH takes place in the solution phase using a continuous stirred tank reactor equipped with jacketed cooling. The polymerization reaction is very exothermic; heat removal is essential to control the reaction. Feeds to the reactor are a combination of both fresh and recycle ethylene, hydrogen, and VCH. For this reaction, a large excess of VCH is utilized in order to encourage higher levels of VCH incorporation into the polymer.

A mixture of ethylene and hydrogen feed in the mole ratio of approximately 4 to 1 is sparged through the liquid phase in the presence of the cocatalyst and catalyst, in this case MMAO and rαc-en(THInd)₂ZrCl₂, respectively, in a 2000:1 molar ratio Polymerization with this catalyst is achieved at the fairly mild conditions of 131°F (55°C) with an ethylene partial pressure of 18 psig, and 5 psig hydrogen. Concentration of the polymer in VCH effluent from the reactor is assumed not to exceed 10%, which is the approximate solubility limit of EVCH in VCH under these conditions.

Immediately after leaving the reactor, the effluent is heated to 93 °C (200°F) before entering a vacuum flash separator. Pressure in this vessel operated under vacuum is approximately 2 psia, causing ethylene and a large portion of the VCH to flash from the polymer and leave with the overhead gas stream. This overhead gas stream is then sent to the reactant recovery area for recovery of unreacted ethylene and VCH. The polymer bottom fraction leaves the flash vessel and is sent to the polymer purification and compounding area for further clean-up before pelletizing the EVCH.

Devolatilization and Polymer Isolation

The polymer leaving the flash separator is fed to a two-stage thin film wiped film evaporator (TFE) where VCH incorporated in the polymer is reduced to low residual levels. A thin film evaporator was chosen for this application for several reasons. First, the TFE provides good temperature control because heat is added to the device through the cylindrical walls to the thin polymer film. Tight control of the heat history of the polymer is crucial to minimize thermal degradation. Second, the turning action by the wiped blades in the TFE continuously renews or refreshes the polymer surface to maximize removal of the VCH. Third, the TFE operates under vacuum using N₂ as the stripping gas to further enhance removal of unreacted VCH and result in low VCH residuals in the final product. (Steam may also be used as the stripping gas).

After leaving the TFE, the polymer passes through a gear pump to an extruder. This extruder may be operated under vacuum to improve devolatilization of any remaining monomer or comonomer. The extruder is equipped with an underwater pelletizer. The pellets are then dried and sent to storage silos for later boxing or loading onto railcars or trucks.

Reactant Recovery Area

VCH and other volatile compounds present in the overhead stream from the TFE are condensed for separation from the N₂ stripping gas. With the exception of a small purge, the N₂ is recycled. VCH recovered from this stream, along with any condensable volatile compounds are sent to the distillation tower for separation.

The overhead stream from the flash separator is rich in VCH as well as ethylene. This stream passes through several condensers to separate the VCH and other condensable byproducts from the ethylene before entering the vacuum pump. Removal of the condensable materials from this stream is necessary to reduce the size of the vacuum pump required. The. gas stream leaving the vacuum pump still contains a significant quantity of ethylene and hydrogen. These gases, together with the VCH vapors and VCH liquid from the condenser, are sent to the distillation column for further separation.

In the distillation tower, VCH is recovered from the process streams and recycled back to the polymerization reactor. This area can consist of only one distillation column. Reactant gases are recovered from the top of the column and VCH from the bottom. However, depending on the purity level required of the recycle VCH, a second column may be necessary for separation of the heavier reaction byproducts from the recovered VCH.

In this example, the overhead gas stream from the column is sent to a series of deoxo vessels and driers to remove trace quantities of oxygen incorporated into the system by vacuum leaks, before recycling to the reactor.

The method disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the method of this invention have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations may be applied to the method and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit and scope of the invention. More specifically, it will be apparent that certain agents which are chemically related may be substituted for the agents described herein while the same or similar results would be achieved. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the invention as defined by the appended claims.

REFERENCES

The following references, to the extent that they provide exemplary procedural or other details supplementary to those set forth herein, are specifically incorporated herein by reference.

US 5,981,676 WO 09916824 Al US 5,049,624

Claims

WHAT IS CLAIMED IS:

1. A method of synthesizing a polymer, comprising: providing a monomer, a comonomer, and a catalyst; reacting the monomer and the comonomer in the presence of the catalyst in a reactor, under conditions wherein the monomer is a liquid in which the comonomer is soluble, to yield a polymer comprising the monomer and comonomer; and separating unreacted monomer and unreacted comonomer from the polymer, to yield the purified polymer.

2. The method of claim 1 , wherein the monomer comprises an ethylenic group and a pendant group comprising a cyclic olefinic group.

3. The method of claim 2, wherein the pendant group comprises a polycyclic group.

4. The method of claim 2, wherein the monomer comprises a cyclic olefinic pendant group having the structure I:

wherein qi, q₂, q₃, q₄, and r are independently selected from hydrogen, methyl, or ethyl; m is -(CH₂)_n-, wherein n is an integer from 0 to 4, inclusive.

5. The method of claim 4, wherein the monomer is selected from vinyl cyclopentene, 4- vinyl-1-cyclohexene, vinyl cycloheptene, or vinyl cyclooctene.

6. The method of claim 1 , wherein the comonomer comprises an ethylenic group.

7. The method of claim 6, wherein the comonomer is selected from ethylene or styrene.

8. The method of claim 1, wherein the catalyst is a supported or an unsupported Ziegler- Natta catalyst or a supported or an unsupported metallocene catalyst.

9. The method of claim 8, wherein the catalyst is selected from rαc-en(Ind)₂ZrCl₂/MMAO, røc-en(THInd)₂ZrCl₂/MMAO, or (C₅Me₄SiMe₂NBu^t)TiCl₂/MMAO.

10. The method of claim 9, wherein the catalyst is (C₅Me₄SiMe₂NBu^t)TiCl₂ MMAO.

11. The method of claim 1, wherein the providing step comprises providing a second comonomer; the reacting step comprises reacting the monomer, the comonomer, and the second comonomer; and the separating step comprises separating unreacted second comonomer.

12. The method of claim 1 , further comprising purifying the monomer and the comonomer before the reacting step.

13. The method of claim 11, further comprising purifying the second comonomer before the reacting step.

14. The method of claim 1 , further comprising recycling unreacted monomer to the reactor.

15. The method of claim 1, furtlier comprising recycling unreacted comonomer to the reactor.

16. The method of claim 11 , further comprising recycling unreacted second comonomer to the reactor.

17. The method of claim 1 , wherein the reacting step further comprises reacting the monomer and the comonomer in the presence of a process gas.

18. The method of claim 11 , wherein the reacting step further comprises reacting the monomer, the comonomer, and the second comonomer in the presence of a process gas.

19. The method of claim 1 , wherein the reactor is a continuously agitated reactor.

20. The method of claim 1, wherein the reactor is at a temperature between about 38°C (100°F) and about 93°C (200°F).

21. The method of claim 20, wherein the reactor is at a temperature between about 60°C (140°F) and about 82°C (180°F).

22. The method of claim 1 , wherein the reactor is at a pressure between about ambient and about 300 psi.

23. The method of claim 1 , wherein the separating step comprises heating the polymer to about 38°C (100°F) to about 149°C (300°F).

24. The method of claim 1, wherein the separating step comprises subjecting the polymer to vacuum flashing.

25. The method of claim 1, wherein the separating step comprises passing the polymer through a wiped film evaporator.

26. The method of claim 1, wherein the separating step comprises solvent extraction.

27. The method of claim 26, wherein the solvent in the solvent extraction is methanol.

28. The method of claim 1, wherein the separating step comprises supercritical fluid extraction.

29. The method of claim 28, wherein the supercritical fluid is CO₂ or isobutane.

30. The method of claim 1, wherein the separating step comprises stripping the polymer with a stripping gas.

31. The method of claim 30, wherein the stripping gas is selected from N or steam.

32. The method of claim 1, wherein the separating step comprises heating the polymer to less than about 149°C (300°F), subjecting the polymer to vacuum flashing, passing the polymer through a thin film evaporator, and stripping the polymer with N₂ or steam.

INTERNATIONAL SEARCH REPORT Intel nal Application No

PCT/US 01/23338

A. CLASSIFICATION OF SUBJECT MATTER ,

IPC 7 C08F210/02 C08F2/06 //(C08F210/02,232:06)

According to International Patent Classification (IPC) or to both national classification and IPC

B. FIELDS SEARCHED

Minimum documentation searched (classification system followed by classification symbols)

IPC 7 C08F

Documentation searched other than minimum documentation to the extent that such documents are included in the fields searched

Electronic data base consulted during the international search (name of data base and, where practical, search terms used)

EPO-Internal , PI Data

c DOCUMENTS CONSIDERED TO BE RELEVANT

Category ⁰ Citation of document with indication where appropriate of the relevant passages Relevant to claim No

WO 8804674 A (EXXON CHEMICAL PATENTS INC) 1-9 ,

30 June 1988 (1988-06-30) 11-23, cited in the appl ication 25,30,31 page 17, l i ne 38 -page 21 , l i ne 19 ; cl aims

1 , 31-35; examples

W099 45047 A (EXXON CHEMICAL PATENTS INC) 1-4, 10 September 1999 ( 1999-09-10) 6-25, 30-32 page 3 , l i ne 5 -page 6 , l i ne 26 1,28,29 page 10, l i ne 5 - l i ne 26 page 14, l i ne 25 -page 15 , l i ne 13 page 21 , l i ne 1 - l i ne 18; cl aims ; exampl es

US 4902780 A (BOURRAIN PAUL ET AL) 1,28,29 20 February 1990 (1990-02-20) cl aims ; examples

-/--

Further documents are listed in the continuation of box C |χ I Patent family members are listed in annex

¹ Special categories of cited documents

"T" later document published after the international filing date or pnoπty date and not in conflict with the application but

'A" document defining the general state of the art which is not cited to understand the principle or theory underlying the considered to be of particular relevance invention

Ε" earlier document but published on or after the international "X" document of particular relevance, the claimed invention filing date cannot be considered novel or cannot be considered to

"L" document which may throw doubts on prioπty clalm(s) or involve an inventive step when the document is taken alone which is cited to establish the publication date of another "Y" document of particular relevance, the claimed invention citation or other special reason (as specified) cannot be considered to involve an inventive step when the

"θ" document referring to an oral disclosure, use exhibition or document is combined with one or more other such docuother means ments, such combination being obvious to a person skilled

^■P- document published prior to the international filing date bul in the art later than the prioπty date claimed "&" document member of the same patent family

Date of the actual completion of the international search Date of mailing of the international search report

23 January 2002 31/01/2002

Name and mailing address of the ISA Authorized officer

European Patent Office P B 5818 Patentlaan 2 NL- 2280 HV Rιjswijk Tel (+31-70) 340-2040, Tx 31 651 epo nl, Fax (+31-70) 340-3016 Kaumann , E

Form PCT/ISA 210 (second sheet) (July 1992) page 1 of 2 INTERNATIONAL SEARCH REPORT Inte >nal Application No

PCT/US 01/23338

C(Contlnuation) DOCUMENTS CONSIDERED TO BE RELEVANT

Category ° Citation of document, with indication.where appropriate, of the relevant passages Relevant to claim No

WO 99 16799 A (GAUTHIER WILLIAM JOHN 1-9 , ;M0FFITT RONALD DEAN (US); CRYOVAC INC 11-23, (US);) 8 April 1999 (1999-04-08) 25-27, 30 , 31 claims; example 18

WO 9726287 A (DOW CHEMICAL CO ;FINLAYS0N 1-19 MALCOLM F (US); GARRISON CRAIG C (US);) 24 July 1997 (1997-07-24) page 16, line 33 -page 17, line 18 page 17, line 32 -page 21, line 9 page 34, line 12 - line 30; claims

US 5866 704 A (NICKIAS PETER N ET AL) 1-9 , 2 February 1999 (1999-02-02) 11-20 ,

23-25 column 3, line 12 - line 35 column 14, line 21 - line 25; claims

WO 93 21242 A (EXXON CHEMICAL PATENTS INC) 1-19,24 ,

28 October 1993 (1993-10-28) 25 page 11, line 26 page 34, line 6 -page 36, line 6; claims; examples

US 5837791 A (ISHIDA TATSUY0SHI ET AL) 1-11 17 November 1998 (1998-11-17) column 30, line 31 - line 64 column 50, line 64; claims

EP 0 707 014 A (IDEMITSU KOSAN CO) 1-8

17 April 1996 (1996-04-17) col umn 13, l i ne 6 - l i ne 30; cl aims

Form PCT/ISA 210 (continuation of second sheet) (July 1992) page 2 of 2 Intel tal Application No

■Information on patent family me oers

PCT/US 01/23338

Patent document Publication Patent family Publication cited in search report date member(s) date

WO 8804674 A 30-06-1988 AT 101861 T 15-03-1994

AU 614505 B2 05-09-1991

AU 1085588 A 15-07-1988

BR 8707598 A 03-10-1989

CA 1327864 Al 15-03-1994

DE 3789147 Dl 31-03-1994

DE 3789147 T2 26-05-1994

DK 466288 A 19-10-1988

EP 0273654 A2 06-07-1988

ES 2050669 T3 01-06-1994

FI 883825 A 18-08-1988

IL 84641 A 25-05-1992

IN 172045 Al 20-03-1993

JP 2711403 B2 10-02-1998

JP 1501556 T 01-06-1989

KR 9508721 Bl 04-08-1995

NO 883654 A 16-08-1988

NZ 222851 A 26-07-1990

PT 86409 A , B 01-01-1988 O 8804674 Al 30-06-1988

YU 230487 Al 30-06-1989

WO 9945047 A 10-09-1999 AU 2801899 A 20-09-1999

AU 2886199 A 20-09-1999

AU 2894299 A 20-09-1999

AU 3067899 A 20-09-1999

BR 9907754 A 17-10-2000

BR 9907924 A 28-11-2000

BR 9907954 A 24-10-2000

CN 1291204 T 11-04-2001

CN 1292004 T 18-04-2001

CN 1291999 T 18-04-2001

EP 1060198 Al 20-12-2000

EP 1060199 Al 20-12-2000

EP 1064311 Al 03-01-2001

EP 1062254 Al 27-12-2000 O 9945047 Al 10-09-1999

WO 9945040 Al 10-09-1999

WO 9945041 Al 10-09-1999

WO 9945042 Al 10-09-1999

US 6329477 Bl 11-12-2001

US 6262202 Bl 17-07-2001 us 6291609 Bl 18-09-2001 us 6218488 Bl 17-04-2001

US 4902780 A 20-02-1990 FR 2611207 Al 26-08-1988

AU 1191288 A 25-08-1988

EP 0281464 Al 07-09-1988

HU 46345 A2 28-10-1988 P 63205309 A 24-08-1988

NZ 223545 A 28-06-1989

ZA 8801147 A 15-08-1988

WO 9916799 A 08-04-1999 US 6313241 Bl 06-11-2001

AU 9775598 A 23-04-1999

BR 9812705 A 22-08-2000

EP 1023344 Al 02-08-2000 P 2001522894 T 20-11-2001

Form PCT/ISA/210 (patent family annex) (July 1992) page 1 of 3 -—-

Inte tal Application No information on patent family memoers

PCT/US 01/23338

WO 9916799 A WO 9916799 Al 08-04-1999

WO 9726287 A 24-07-1997 AU 735241 B2 05-07-2001

AU 1754597 A 11-08-1997

BR 9707015 A 20-07-1999

CA 2242144 Al 24-07-1997

CZ 9802309 A3 12-05-1999

EP 0876411 Al 11-11-1998 P 2000503333 T 21-03-2000

NO 983355 A 22-09-1998

PL 327991 Al 04-01-1999

WO 9726287 Al 24-07-1997

US 6335410 Bl 01-01-2002

US 6054544 A 25-04-2000

ZA 9700485 A 21-07-1998

CN 1209816 A 03-03-1999

US 5866704 A 02-02-1999 US 5959047 A 28-09-1999

AU 719500 B2 11-05-2000

AU 4145697 A 06-03-1998

AU 726123 B2 02-11-2000

AU 5152198 A 15-07-1998

BR 9711124 A 28-09-1999

BR 9712535 A 19-10-1999

CN 1230190 A 29-09-1999

CN 1233253 A 27-10-1999

CZ 9900423 A3 14-07-1999

EP 0923589 Al 23-06-1999

EP 0946574 Al 06-10-1999

HU 9902581 A2 29-11-1999

JP 2000516228 T 05-12-2000

JP 2001506260 T 15-05-2001

NO 990545 A 26-03-1999

NO 991816 A 16-04-1999

SK 15399 A3 10-04-2000

TR 9900487 T2 21-06-1999

TR 9900841 T2 21-06-1999

TW 397845 B 11-07-2000

WO 9806727 Al 19-02-1998 O 9827102 Al 25-06-1998

US 6268444 Bl 31-07-2001

WO 9321242 A 28-10-1993 CA 2129540 Al 28-10-1993

DE 69322082 Dl 17-12-1998

DE 69322082 T2 17-06-1999

EP 0641362 Al 08-03-1995

ES 2126647 T3 01-04-1999 P 2888639 B2 10-05-1999 P 7505912 T 29-06-1995

US 5444145 A 22-08-1995 O 9321242 Al 28-10-1993

US 5844055 A 01-12-1998

US 5837791 A 17-11-1998 CA 2153374 Al 07-01-1996

CA 2153384 Al 07-01-1996

CN 1135491 A 13-11-1996

CN 1119179 A 27-03-1996

DE 69500978 Dl 11-12-1997

Form PCT/ISA 210 (patent family annex) (July 1902) page 2 of 3 Inte nal Application No

■^formation on patent family members

PC l /US 01/23338

US 5837791 DE 69500978 T2 26-03- 1998 DE 69516216 Dl 18-05- 2000 DE 69516216 T2 19-10- 2000 EP 0691319 Al 10-01- 1996 EP 0691354 Al 10-01- 1996 P 8325170 A 10-12- 1996 P 8325334 A 10-12- 1996 SG 32396 Al 13-08- 1996 US 5698751 A 16-12- 1997

EP 0707014 17-04-1996 JP 3189175 B2 16-07-2001 JP 7018023 A 20-01-1995 DE 69416589 Dl 25-03-1999 DE 69416589 T2 24-06-1999 EP 0707014 Al 17-04-1996 US 5747613 A 05-05-1998 WO 9501379 Al 12-01-1995

Form PCT/ISA 210 (patent family annex) (July 1GS2) page 3 of 3