Oligomeric Oxolanyl Alkanes As Randomizers for Copolymerization

Europaisches Patentamt J European Patent Office Publication number: 0 215 256 Office europeen des brevets A1

EUROPEAN PATENT APPLICATION

0 Designated Contracting States: © Inventor: Hall, James E. BE DE FR GB IT NL 2940 Mayfair Road Akron OH 4431 2(US) Inventor: Malani, Shrikant R. 460 Treeside Drive AKron OH 4431 3(US)

0 Representative: Kraus, Walter, Dr. et al Patentanwalte Kraus, Weisert & Partner Thomas-Wimmer-Ring 15 D-8000 Miinchen 22(DE)

0 Oligomeric oxolanyl alkanes as randomizers for copolymerization.

© A process is disclosed herein for preparing randomized copolymers of conjugated dienes and vinyl aromatic hydrocarbons by utilizing oligomeric oxolanyl alkanes in amounts which effectively promote the randomization of the copolymers so produced.

CO in e>i in

Ol w

Xerox Copy Centre 0 215 256

OL1GOMERIC OXOLANYL ALKANES AS RANDOMIZERS FOR COPOLYMERIZATION

pound and an oligomeric oxolanyl alkane. At least BACKGROUND OF THE INVENTION one of the two monomers is selected from the group consisting of conjugated dienes having from The use of oligomeric oxolanyl alkanes and four to 12 carbon atoms per molecule. The other hydrocarbyl alkali metal compounds such as butyl- 5 monomer is selected from the group consisting of lithium as co-initiators in the copolymerizations of vinyl aromatic hydrocarbons having from eight to dienes such as butadiene with styrene is well 20 carbon atoms per molecule. known as disclosed in U.S. 4,429,090 and U.S. The oligomeric oxolanyl alkane randomizing 4,429,091, to James E. Hall. agents of the present invention are extremely sta- Styrene and 1,3-butadiene form block w ble at high polymerization temperatures such as copolymers when polymerized anionically in non- temperatures exceeding 90 °C thus allowing poly- polar solvents. Modifiers for anionic polymerization merizations to be run in an economical low cost are known which will randomize 1,3- manner while eliminating detrimental side reac- butadiene/styrene copolymerizations however tions. many of these modifiers are not suitable for use at 75 The oiigomeric oxolanyl alkane is present in higher temperatures. the polymerization reaction in a quantity sufficient This invention relates to the use of oligomeric to promote formation of random copolymers, it oxolanyl alkanes as randomizers for being considered that in the absence of the butadiene/styrene copolymerizations. oiigomeric oxolanyl alkane or other randomizers, 20 substantially no random copolymers are produced but that block polymers are formed. The oligomeric SUMMARY OF THE INVENTION oxolanyl alkane randomizers reduce or eliminate both terminal and branch blocking of the conju- A process is disclosed herein for preparing gated diene and vinyl aromatic hydrocarbons used randomized copolymers of conjugated dienes and 25 to prepare the copolymers of the present invention. vinyl aromatic hydrocarbons by utilizing oligomeric In the preferred embodiment of this invention oxolanyl alkanes in amounts which effectively pro- the two monomers, the conjugated dienes and the mote the randomization of the copolymers so pro- vinyl aromatic hydrocarbons, are present in a mon- duced. omer ratio of from about 90 to 10 to about 40 to 60. 30 The oligomeric oxolanyl alkanes hereinafter alternatively referred to as oxoianyl alkanes which DESCRIPTION OF THE INVENTION are used as randomizers in the present invention are represented by the structural formulas I and II: According to this invention there is provided a process for preparing randomized copolymers 35 which comprises contacting at least two different monomeric materials with an organolithium com-

so 0 215 256

(I) O | »

" «r S, ^ k«, -»/

(II)

wherein R, and R2 independently are hydrogen or The cyclic oxolanyl oligomer randomizer pre- an alkyl group and the total number of carbon 20 cursors are formed only by the reaction of a furan atoms in -CR,Rj-is between one and nine inclusive; compound which is unsubstituted in the 2,5-posi- y is an integer of I to 5 inclusive, y1 is an integer of tion with one or more aldehydes, or one or more 3 to 5 inclusive, Rr, R3, R, and R5 independently ketones, or a mixture thereof. are -H or -CnH2n+1 wherein n = l to 6. Suitable oligomeric randomizers for use in the While the randomizers of structural formula I 25 catalyst system include but are not limited to: bis- linear are oligomers and the modifiers represented (2-oxolanyl) methane; 2,2-bis(2-oxolanyl) propane; by structural formula II are cyclic oligomers, l,l-bis(2-oxolanyl) ethane; 2,2-bis(2-oxolanyl) bu- hereinafter the term oxolanyl randomizers is con- tane; 2,2-bis(5-methyl-2-oxolanyl) propane; 2,2-bis- templated to encompass the randomizers of both (3,4,5-trimethyl-2-oxolanyl) propane. These ran- structural formulas. 30 domizer compounds represent a few of the dimer The oxolanyl randomizers are prepared by compounds represented by structural formula I and methods known to those skilled in the art. Typically other linear and cyclic oligomer randomizers are the modifiers are prepared by reacting furan, which apparent from their structural formulas. is unsubstituted in either or both of the 2-or 5- The preferred oxolanyl randomizers for use in positions, with either an aldehyde or a ketone, such 35 the present invention are the dimeric 2,2-bis(2- as acetone, in the presence of an acid such as oxolanyl) propane and the trimeric 2,5-bis(2- hydrochloric acid. Careful control of the reaction oxolanyl-2-propyl) oxolane. parameters allows for the production of a product The oligomeric oxolanyl alkane can be intro- containing up to 95 percent of dimers, trimers, and duced into the polymerization in any manner. It can tetramers. Once the linear oligomers or cyclic 40 be introduced together with hydrocarbyllithium in- structures are formed these reaction products are itiator into the polymerization reaction or the hydrogenated in the presence of suitable hydroge- oligomeric oxolanyl alkane can be introduced into nation catalysts such as nickel based catalysts. the polymerization reaction mixture into which the Any suitable hydrogenation process known in the hydrocarbyllithium has been introduced as an in- art be may employed to produce the randomizer 45 itiator. In either embodiment, the oligomeric ox- compounds of structural formulas I or II. olanyl alkanes can be employed individually or as While unsubstituted furans are the preferred mixtures with other oxolanyl alkanes. reactant, 2-alkyl-furans containing up to six carbon The oligomeric oxolanyl alkanes employed in atoms in the alkyl group can be employed in the accordance with the method of this invention in of production the oxolanyl oligomers of structural 50 polymerization reactions which are conducted un- formula I. When 2-alkyl-furans are employed in the der any of those reaction conditions conventionally production of randomizers furfuryl dimers are the employed in solution polymerization with hydrocar- main reaction product. The 2-alkyl-furan also may byllithium initiators which involve the copolymeriza- end cap any oligomers formed if furan is used as a tion of two monomeric materials, i.e., conjugated coreactant. 55 diolefins, including butadiene and isoprene and vinyl aromatic hydrocarbons such as styrene and related hydrocarbons. If the polymerization mixtures into which an oligomeric oxolanyl alkane has 0 215 256 been introduced are to be treated with polymer dimethyl-l-vinylnaphthalene; 2,4,6-trivinyltoluene; coupling agents or other reagents which depend and 2,4,6-triisopropenyl-toluene. Again reference is upon the presence of terminal polymer-lithium made to U.S. Patent No. 3,377,404 for disclosures groups, the coupling agent or other reagent should of additional vinyl-substituted aromatic compounds be added as soon as practicable, for example, 5 which are incorporated herein by reference. within 15 minutes, after the desired monomer con- In the process of the present invention the version has been attained. randomization of the conjugated dienes and vinyl- Regardless of the method of their employment, substituted aromatic monomers is effective in mon- that is, whether they are reacted with the hydrocar- omer ratios ranging from 10-50% vinyl-substituted byllithium and introduced in the form of the reac- to aromatic hydrocarbons to 90-50% conjugated tion product or whether they are introduced, as diene. The randomization process is especially ef- such, into the reaction mixture, the oligomer ox- fective when the monomer ratio is from 30-40% olanyl alkanes will be employed in quantities suffi- vinyl-substituted aromatic hydrocarbon to 70-60% cient to provide from about 0.004 to about 2.0, conjugated diene. preferably 0.006 to I.5, parts per I00 parts of mon- 75 Any organolithium catalyst which are known in omers for polymers of 1,000 to 500,000 M n. the art as being useful in the polymerization of If introduced into the reaction mixture as such, vinyl aromatic hydrocarbons and conjugated dienes the oligomeric oxolanyl alkane is conveniently intro- can be employed in the present invention . Suitable duced in a hydrocarbon, e.g., hexane, solution. catalysts which initiate polymerization of the mon- As previously discussed at least one of the two 20 omer system include organolithium catalysts which monomers which is to be randomized in the have the formula R(Li)X" wherein R represents a present invention is selected from the group con- hydrocarbyl radical of I to 20, preferably 2-8, car- sisting of one or more conjugated dienes having bon atoms per R group, and x" is an integer of 1-4. from four to 12 carbon atoms per molecule. Exam- Typical R groups include aliphatic radicals and ples thereof include the following: 1,3-butadiene; 25 cycloaliphatic radicals, such as alkyl, cycloalkyl, isoprene; 2,3-dimethyl-l,3-butadiene; 1,3-pen- cycloalkylalkyl, alkylcycloalkyl, aryl and alkylaryl tadiene (piperylene);2-methyl-3-ethyl-l,3-butadiene; radicals. 3-methyl-l,3-pentadiene; 1,3-hexadiene; 2-methyl- Specific examples of R groups for substitution 1,3-hexadiene; 3-butyl-l,3-octadiene, and the like. in the above formula include primary, secondary Among the dialkylbutadienes, it is preferred that 30 and tertiary groups such as methyl, ethyl, n-propyl, the alkyl groups contain from one to three carbon isopropyl, n-butyl, isobutyl, t-butyl, n-amyl, isoamyl, atoms. Numerous others are disclosed, for instance n-hexyl, n-octyl, n-dedyl, cyclopentyl-methyl, in U.S. Patent No. 3,377,404, the disclosure with cyclohexyi-ethyl, cyclopentyl-ethyl, methyl- respect to which is incorporated herein by refer- cyclopentylethyl, cyclopentyl, cyclohexyl, 2,2,1- ence. The preferred 1,3-diene monomer for use in 35 bicycloheptyl, methylcyclopentyl, dimethyl- the present invention is butadiene. cyclopentyl, ethylcyclopentyl, methylcyclohexyl, In addition to the above described conjugated dimethylcyclohexyl, ethylcyclohexyl, isopropyl- dienes, one or more suitable copolymerizable mon- cyclohexyl, and the like. omers such as vinyl-substituted aromatic mon- Specific examples of other suitable lithium omers are incorporated into the polymerization 40 catalysts include: mixture. Examples of suitable copolymerizable monomers for use in the preparation of copolymers phenyllithium, naphthyllithium, 4-butylphenyllithium, in the present invention include: styrene; alpha- p-tolyllithium, 4-phenylbutyllithium; 4-butyl- methylstyrene; l-vinylnaphthalene; 2-vinyinaph- cyclohexyllithium, 4-cyclohexylbutyllithium, 1,4- thalene; l-alpha-methylvinyl-naphthalene; 2-alpha- 45 dilithiobutane, 1,10-dilithiodecane, 1,20- methylvinylnaphthalene; l,2-diphenyl-4- dilithioeicosane, 1,4-dilithiobenzene, 1,4-dilithionaph- methylhexene-l; l,6-diphenyl-hexadiene-l,5; 1,3- thalene, 1,10-dilithioanthracene, l,2-dilithio-l,2- divinylbenzene; 1,3,5-trivinylbenzene; 1,3,5- diphenylethane, 1,3,5-trilithiopentane, 1,5,15- triisopropenylbenzene; 1,4-divinylbenzene; 1,3-dis- trilithioeicosane, 1,3,5-trilithiocycIohexane, 1,3,5,8- tyrylbenzene; 1,4-distyrylbenzene; 1,2-distyrylben- 50 tetralithiodecane, 1,5,10,20-tetralithioeicosane, zene; and mixtures of these as well as alkyl, 1,2,4,6-tetralithiocyclohexane, 4,4'-dilithiobiphenyl, cycloalkyl, aryl alkaryl and aralkyl derivatives there- and the like. of in which the total number of carbon atoms in the Mixtures of different lithium catalysts can also combined hydrocarbon constitutes generally not be employed, preferably containing one or more greater than 12. Examples of these latter com- 55 lithium compounds such as R(Li)x-. The preferred pounds include: 4-methylstyrene; vinyl toluene; 3,5- lithium catalyst for use in the present invention is diethylstyrene; 2-ethyl-4-benzylstyrene; 4-phenyl- n-butyllithium. styrene; 4-p-tolylstyrene; 2,4-divinyltoluene; 4,5- 0 215 256

Other lithium catalysts which can be employed ployed, such as IOO°C. to I2O°C, and it is preferred are lithium dialkyl amines, lithium dialkyl that the polymerization process be maintained in a phosphines, lithium alkyl aryl phosphines and lith- range of from 70 °C. to 200 °C, most preferably ium diaryl phosphines. 100 °C. to 140 °C. Oxygen equivalents as herein discussed are 5 The polymerization reaction can be performed the moles in equivalents of oxygen contained in the at any pressure convenient up to 100 atmospheres. oxolanyl alkane randomizer rather than the moles When the desired degree of polymerization has of the randomizer compounds. Randomizer dimers been reached, the copolymer can be isolated by contain two equivalents of oxygen per mole while precipitation with a non-solvent such as methanol, trimers contain three equivalents of oxygen per 10 isopropanol or water and an appropriate antioxidant mole. can be added at this stage of polymerization. Alter- The oxygen equivalent ratios of the present natively, the solution can be injected into a slurry invention represents the ratio of the oxygen equiv- tank containing a hot non-solvent whereupon the alents of the oxolanyl alkane randomizers to the solvent is flashed off and the copolymer remains as mole equivalents of organolithium catalyst initiators. 75 a slurry with the non-solvent. Alternatively, the sol- The oxygen equivalent ratios utilized in the instant vent can be removed directly by the application of invention can vary from 0.2/I.0 to 2.0/I.0, preferably heat and/or flashing to a lower pressure. The num- from 0.5/I.0 to I.5/I.0. ber average molecular weight of the final The amount of oxolanyl alkane randomizer as copolymer produced can range from 1,000 to well as its ratio to the organolithium catalyst deter- 20 500,000. These copolymers depending on their mines the vinyl content (l,2-microstructure) of the molecular weight and composition can be used for conjugated diene contributed units in the a variety of applications ranging from molding ma- copolymer finally produced. It has been determined terials, rubber goods such as tires, and various that the conjugated diene vinyl aromatic hydrocar- adhesive applications. bon copolymers produced according to the pro- 25 It is believed that one skilled in the art can, cess of the present invention should have a vinyl using the preceding description, utilize the present content ranging between about ten (10) to thirty - invention to its fullest extent. The following pre- (30) percent, preferably 10 to 20 percent vinyl con- ferred specific embodiments are therefore to be tent. construed as merely illustrative of the randomiza- The present polymerization system is applica- 30 tion system and the polymerization process of the ble to solution polymerization techniques which are present invention. conducted at temperatures above 0°C, preferably 90° to I6O°C. Reaction temperature below 90°C. temperature range normally produce copolymers EXAMPLE I containing high l,2-microstructure. Reaction tern- 35 peratures between 70°C. and I4O°C. generally pro- The following polymerization batch reactions duce copolymers containing between 10 and 30 utilized 21.9 percent monomer (35% styrene and percent of a l,2-microstructure. Any temperature in 65% 1,3-butadiene) in hexane in a bottle. The ox- this of 0°C. range to 160° C. which gives a conve- olanyl randomizer 2,2-bis(2-oxolanyl) propane - nient polymerization rate while producing a 40 (OOPS) was introduced into the reaction mixture in copolymer having a 1,2-microstructure ranging be- the amount indicated and butyllithium was added in tween 10 and 30 percent is acceptable. If the opera- the amount of 1.0 millimole per 100 grams of mon- tion is to be conducted as a batch operation, initi- omer. The reaction was conducted at the tempera- ation temperatures of less than 90°C. are pre- ture or inclining temperature range indicated. After ferred. If the operation is to be a continuous opera- 45 polymerization was completed the resultant product tion higher initiation temperatures can be em- was tested for vinyl content, bound styrene and block styrene.

55 0 215 256 10

Approx. Oxygen "OOPS" Equiv. Monomer Vinyl Bound Block(a' Demand Ratio Conversion Temp. Content Styrene Styrene (Calculated)

OOPS/ lbs./lOOO n-BuLi % 'F. % lbs. Rubber

0 91.6 170 10.1 31.3 9.2 0 1 93.2 170 58.0 31.0 0 0.7 2 93.9 170 64.6 31.9 0 1.4

(a) Determined by chemical block analysis (ASTM D 3314-74 Part

37).

EXAMPLE II

In 20 the following polymerization reactions, the butadiene/styrene copolymerizations were identical to those of Example I except that the reactions were carried out in a one gallon batch reactor

Oxygen Equiv. Vinyl Bound Block Ratio Temp. Content Stvrene Styrene

OOPS/ Chem^b> NMR(c) n-BuLi °F. % % Block Block

ONE GALLON BATCH

0 245-275 11.9 50.0 16.0 28.4 0 207-255 11.0 41.6 9.2 27.0 0.25 208-256 14.0 43.1 4.3 23.6 0.50 208-253 17.2 41.2 10.9 18.8 0.75 208-249 19.7 43.8 6.1 12.1 1.0 208-243 24.7 35,0 0.6 1.3 1.0 210-242 21.3 43.2 0.0 2.8 1.0 245-275 18.3 42.1 0.2 3.4 2.0 209-232 30.2 46,0 0.0 0.0 2.0 245-275 16.1 33.7 0.0 0,0

(b) Determined by chemical block analysis.

EXAMPLE III

In the following polymerization reactions, the 55 1,3-butadiene/styrene monomer ratio was 60/40 to 50/50 and the reactions were conducted at a temperature of 210-275 °F. in a one gallon batch reactor in accordance with the procedure of Example I: 11 0 215 256 12

Oxygen Equiv. Monomer Vinyl Bound Block Ratio Conversion Content Styrene Styrene

OOPS/ Chem NM.R n-3uLi % % % Block Block

0 89 11.9 50.0 16.0 28.0 0-5 95 17.2 41.2 10.9 18.8 0-75 94 19.7 43.8 6.1 12.1 1-0 93 21.3 43.2 0.0 3.0 2.0 94 30.2 46.0 0.0 0 0

The above data demonstrates the high effi- Example IV ciency of oiigomeric oxolanyl alkanes as a copolymerizing randomizing agent. In the following polymerization reactions, the It will be evident that various modifications can 20 butadiene/styrene copolymerizations were identical be made to the process of this invention. These to those of Example I except that the reactions modifications, however, are considered as being were carried out in a 50 gallon continuous reactor: within the scope of the invention.

Oxygen E<3^iv. Vinyl Bound Block Ratio Temperature Content Styrene Stvrene

°ops/ chem NMR n-BuLi °f. % % Block Block

0 200-250 14.0 27.1 8.7 0.64 200-250 17.0 33.7 0.2 1.40 200-250 23.9 25.8 0.8 1.51 200-250 28.6 31.6 1.0 2.0 200-244 25.9 31.5 0.0

molecule and at least one monomer of a vinyl- substituted aromatic hydrocarbon having from eight Claims to 20 carbon atoms per molecule with a randomiz- 45 ing initiation system comprising an organolithium I. A process for preparing copolymers which compound and an oxolanyl alkane selected from comprises contacting at least one monomer of a the group consisting of: conjugated diene having four to 12 carbons per

55 13 0 215 256 14

(•) I" T •Rj Ri Rs ■R)

(">

wherein R, and R2 independently are hydrogen or 4. The process as in claim I wherein the con- an alkyl group and the total number of carbon 1S jugated diene is l,3-butadiene. atoms in -CR,R2-ranges between one and nine in- 5. The process as in claim I wherein the vinyl clusive; y is an integer of I to 5 inclusive, y' is an substituted aromatic hydrocarbon is styrene. integer of 3 to 5 inclusive Rr, R3, R« and R5 6. The process as in claim I wherein the ox- independently are -H or -CnH2n+1 wherein n = l to 6, olanyl alkane is 2,2-bis(2-oxolanyl) propane. the oxolanyl alkane being present in a quantity 20 7. The process as in claim I wherein the or- sufficient to promote formation of random ganolithium compound is n-butyllithium. copolymers containing a l,2-vinyl content ranging 8. The process as in claim I wherein the ox- between 10 and 30 percent and recovering the olanyl alkane and the organolithium compounds are copolymers. present in an oxygen equivalent ratio ranging from 2. The process as in claim I wherein the 2S 0.2/I.0 to 2.0/I.0. copoiymer is formed from a ratio of monomers of 9. The process as in claim I wherein the ox- the vinyl substituted aromatic hydrocarbon to the olanyl alkane and the organolithium compounds are conjugated dienes from 10-50/90-50. present in an oxygen equivalent ratio ranging from 3. The process as in claim I wherein the 0.5/I.0 to I.5/I.0. copoiymer contains a l,2-vinyl content ranging be- 30 tween 10 and 20 percent.

55 European Patent Application numDer J) EUROPEAN SEARCH REPORT Office

EP 86 11 0619 DOCUMENTS CONSIDERED TO BE RELEVANT Citation of document with indication, where appropriate, Relevant CLASSIFICATION OF THE Category of relevant passages to claim APPLICATION (Int Cl •»)

D,X US-A-4 429 091 (J.E. HALL) 1-9 C 08 F 236/10 * Claims 1,4,6 * C 08 F 4/48

TECHNICAL FIELDS SEARCHED (Int CM,

C 08 F

The present search report has been drawn up for all claims Place of search Date of completion of the search Examiner THE HAGUE 09-12-1986 VAN HUMBEECK F.W.C. CATEGORY OF CITED DOCUMENTS T : theory or principle underlying the invention E earlier patent document, but published on or X particularly relevant if taken alone after the filing date Y : particularly relevant if combined with another D: document cited in the application document of the same category L ■ document cited for other reasons A technological background 0 : non-written disclosure & : member of the same patent family, corresponding P intermediate document document