DE1245132B - Process for the production of an elastomeric block copolymer - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

C08d

German: 39 c-25/05

Number: 1245 132

File number: S 90638 IV d / 39 c

Filing date: April 20, 1964

Opened on: July 20, 1967

The invention relates to a process for the production of an elastomeric block copolymer by means of multistage Polymerization, with an alkenyl-substituted aromatic hydrocarbon in the first stage in a hydrocarbon solvent in the presence of a lithium based catalyst to form of a block product A - Li, the A component of which has an average molecular weight between 2000 and 100000 has, is polymerized and in the second stage a conjugated diene hydrocarbon ίο added and the polymerization with the formation of an intermediate block copolymer of the configuration A - B-Li, whose B component has an average molecular weight between 5000 and 200000 has continued.

Rubbers and elastomers, both natural and synthetic, must be preserved of useful elastomeric properties are vulcanized, which, however, creates an insolubility in common hydrocarbon solvents. This property can be in certain In cases where solvents or oils can damage the rubber, an advantage be. In many cases, for example when applying paints and films made from such elastomers as well as in the recovery and reuse of waste materials, the insolubility in In reality, however, is a major disadvantage. As a result, in many cases it was necessary to To use vulcanized rubbers in the form of latices, which, however, because of the high, in such Latizes the amount of water present causes high transport costs. In the manufacture of many Molded articles have been found to show that the loss of vulcanized rubber is unusual can be high because most of the waste material from such operations cannot be recovered can be used, except as a filler or regeneration product for a new rubber formulation.

Most thermoplastics, such as polystyrene, do not have this latter drawback, as the at waste material from the manufacture of molded and shaped thermoplastic articles can easily be re-melted and reused. In many cases this would be a mean extremely valuable property of a rubber preparation.

According to German Auslegeschrift 1144 484, it is already known to use block copolymers of the general formula A - B - A in the presence of an organoalkali metal catalyst using a process for the production of an elastomeric one
Block copolymer

Applicant:

Shell Internationale Research Maatschappij N.V., The Hague

Representative:

Dr.-Ing. F. Wuesthoff, Dipl.-Ing. G. Pulse
and Dr. E. v. Pechmann, patent attorneys,
Munich 90, Schweigerstr. 2

Named as inventor:

Ralph Milkovich, Stow, Ohio (V. St. A.)

Claimed priority:

V. St. v. America April 22, 1963 (274 864)

Use the following three monomer groups to produce:

1. Butadiene (1,3), 2-methylbutadiene (1,3), pentadiene (1,3) and vinyl substituted aromatic Hydrocarbons which do not have any substituents on the a-carbon atom;

2. Vinylpyridines and

3. Vinyl halides, vinylidene halides, acrylonitrile, esters of acrylic acid and esters of homologues of acrylic acid.

The block copolymers prepared according to the invention, however, belong to the general one Structure type A - B - C - B - A and are due to this configuration the above Polymers A - B - A in their physical properties, especially in tensile strength and Elongation at break, far superior.

The inventive method is characterized in that in the third stage at least two of the A-B copolymer blocks by adding a dialkenyl-substituted aromatic hydrocarbon couples with each other and then the reaction by adding a chain terminator in ended in a known manner.

According to the invention, a block copolymer of the formula A - B - C - B - A is thus formed, in which A is a non-elastomeric polymer block,

709 617/557

3 4

B an elastomeric polymer block and C a condensate blocks in preferred block according to the invention

dialkenyl aromatic hydrocarbon. Copolymers continue to make 10 to 50 and

The molecular weight of the dialkenyl-substituted is preferably 15 to 40 weight percent of the total

aromatic hydrocarbon in the third stage polymer.

of the block copolymer does not seem to be critical 5 To achieve the highest possible cis content

Size. For economic reasons in the conjugated diene part of the block polymers and

However, this coupling material is preferably based on an economical production of less expensive

a relatively low molecular weight kept polymers, as well as for the simultaneous full-

and should therefore preferably no more than approximate control of the extent and type of

Have 10 monomer units. io polymerization, a relatively neutral carbon

In the polymerization process, all of the alkenyl-substituted lithium-based aroma catalysts are first polymerized in the hydrogen solvent in conjunction with substantially all of the polymeric hydrocarbon monomers. cation used, ie metallic lithium, lithium-The living block polymer is then added to at least alkyls or other organic lithium compounds, a conjugated diene monomer. In particular, lithium alkyl compounds are formed and an elastomeric block is formed, which is bound directly to the very particularly those with up to approximately 8 carbon-plastic, non-elastomeric block and prefers material atoms in the molecule. Suitable lithium carries a lithium ion at its end. The intermediate alkyl compounds include lithium butyls, and the block copolymer consequently has a double, in particular secondary, butyllithium.
block structure A-B-Li in which A is a plastic block, such as polystyrene, and B is an elastomeric, preferably α-olefin or lower alkane, block, such as polyisoprene or polybutadiene. although also aromatic hydrocarbons, such as

In the next third process stage, benzene can be used. The upcoming block copolymers of a dialkenyl-substituted hydrocarbon solvents include aromatic hydrocarbons, such as, for example, cyclic aliphatic hydrocarbons. Divinylbenzene, added. In the presence of the living The polymerization is usually a coupling of a temperature of the order of -20 to two, and sometimes more than two Blockmisch- then takes about 100 ⁰ C at a polymer, and preferably between about polymer molecules. The coupling section is carried out at 20 and 65 ° C. The concentration of at least one and preferably 30 initiators can vary over a relatively wide range from 1 to 25 condensed monomer units of about 1 to 200 ppm, based on the dialkenyl-substituted aromatic hydrocarbons weight of the monomers used, and depends on the substance. the desired molecular weight. When using

The polymerization conditions, catalysts, and dung of a catalyst based on lithium, in the monomers are selected such that an elastomeric 35 plots a solution of the neutral hydrocarbon block or blocks of the Blockmischpolymerisates with fabric and the alkenyl substituted aromatic a glass transition temperature of less than 10 ⁰ C, monomers produced, from which the terminal is preferably formed by less than 0 ° C and best of non-elastomeric polymer block. How less than -25 ° C, is (are) formed. As already stated above, the alkenyl radical is a preferred end product with highly elastomeric properties to 40 wise a vinyl group, the aromatic being preserved, the reaction must be carried out so that a hydrocarbon nucleus monocyclic or polycyclic cis content of at least 85% in the elastomeric and, inter alia, in particular benzene and naph blocks is achieved. The terminal non-elastothalin, but also an alkylated isomer thereof, can have a molecular weight in the range and an alkenyl substituent, preferably from about 200 to 100,000 and a glass transition group can have a vinyl radical. Then the temperature will show over 25 ° C. You should inject lithium initiator, and the reaction, however, preferably each an average molar conditions, such as the monomer content, kular weight of about 5000 to 50,000 and one set so that a terminal non-elastomeric glass transition temperature of over 30 ⁰ C and polymer block with an average molar better of more than 50 ° C. 50 kular weight between approximately 2000 and 100000

The elastomeric block (s) can (can) arise.

Although the initially formed polymer has an average molecular weight of about 10,000 to 1 million, it is preferred to form a single block from the polymer, but a molecular weight between about 25,000 and 500,000. Each elastomeric block in the block is hydrogen As polystyrene, a living polymer, copolymer has two elastomeric segments of the intermediate, which is composed of two parts because it has a lithium ion at the end of its chain. the units of the coupling agent linking these two blocks together with a sufficient amount of a conjugated diolefin can be increased. 60 to continue the polymerization, the intermediate, composed of two parts which are attached to the end of the living polymer copolymers should therefore add an elastomeric chain and the second essential polymer block with an average molecular weight block, namely those from the conjugated in the Of the order of 5,000 to 200,000. Diolefin. In this case should the amount of the difference between the 65 Glasübergangstempera- added conjugated diene to form a two door of the plastic block and that of the elasto-sections having Blockmischpolymerisates mers block should be at least 50 ⁰ C and preferential A - B - Li sufficient that a living block mixture be at least 100 ⁰ C. The terminal polymer is, which carries a lithium ion at the end.

5 6

At this point in the process, the block copolymer containing two hydrocarbons of the benzene series has sections of a block copolymer composed of, for example, styrene, methylstyrene, vinyltoluene, vinyl low molecular weight than it could be useful in most xylene, ethylvinylxylene, isopropylstyrene, ethylvinylelastomeric products, and toluene , tertiary butyl styrene or diethyl styrene, as required at the other end of the elastomeric section 5 and copolymers of at least 70 weight plus a second terminal non-elastomeric percent of one or more such monovinyl blocks. As can be seen from the comparative results of the further substituted aromatic hydrocarbons and the exemplary embodiments listed below, from not more than 30 percent by weight of methylstyrene, this polymer has relatively poor stress, acrylic or methacrylic acid esters.
Elongation properties. The next process - io The polymerization is carried out by removing the still step is consequently the coupling together of the lithium radical block copolymer molecules present on the polymer chain with the formation of polymerisation-coupled chains with at least approximately the break off (proton donors), such as an alcohol, twice the molecular weight of the two sections of water or oxygen, finished,
having mixed polymer. This is accomplished by using a suitable amount of alkenyl injecting a small amount of a dialkenyl substituted aromatic hydrocarbon and substituted aromatic hydrocarbon added to the conjugated diene monomers as well as that, the amount of which is preferably between about 0.5 and 0.5 domes required divinyl substituted aromatic The chains carrying a lithium ion end according to the invention have 20 equivalents per equivalent of their hydrocarbon. The 20 block copolymers produced, a unique reaction, is easily completed in 0.3 to 2 hours while maintaining self-curing properties and excellent elastomer properties at temperatures between approximately 40 and 65 ° C. This elongation measurements, by which they show the state of the time carried out viscosity measurements, enrich technology considerably. In this context, that a substantial increase in the intrinsic viscosity was achieved by almost all other Polymerides product, and clearly show that they sowed a coupling with cis content of the synthetic in addition to the high that between the chains Elastomers back-using the coupling agent has taken place. going physical properties self-curing

Have suitable dialkenyl substituted properties for this purpose.

aromatic hydrocarbons include: 30 Due to the characteristic solubility properties

properties of the self-curing polymers in certain

Divmylbenzene, _th hydrocarbon solvents, such as in

Divinyltoluene, aromatic hydrocarbons, are the same for

Divinylxylene, production of dispersions in oils or fats,

Divinylnaphthalene, _{35 to} increase their toughness or adhesive properties

Divmyläthylbenzol, shafts and to improve the adhesion of such

Divmylbiphenyl, preparations suitable for metallic surfaces,

Diisobutenylbenzene, which is protected and / or lubricated by them

Diisopropenylbenzene. They can also be used in adhesive

Dnsopropenylbiphenyl. _{4O do} g _en use what the ratio of the molecular

weights between the terminal and central

The amount of coupling agents, such as divinyl blocks, with a view to maintaining optimal benzene, is not particularly important as long as properties are matched. They leave them at a relatively low and preferential rate in asphalt while increasing the viscosity at less than about 1 percent by weight of the high temperature and the overall ductility and flexibility in forming the resulting block at low temperature in an amount between so polymerisates used monomer is kept. as little as 0.01 to 75 percent by weight based on As can be seen, ideally only 1 molecule of the entire formulation will disperse. Due to the dialkenyl-substituted aromatic hydrocarbons use of the block polymers in petroleum material to connect two polymer chains 50 grow in an amount of 0.1 to 50 percent by weight, so that a block polymer with terminal properties are the properties of the wax preparations, non-elastomeric blocks and an internal one their flexibility at low temperature results in the coupled elastomeric section. and in terms of their tensile strength over a wide range.
apparently so that branched or star-shaped poly- 55 The new elastomers can be formed with ordinary merisate. Rubber components are mixed, for example

The block coupled together as described above with carbon black, fillers and processing elastomer has an elastomeric polymer oil. The block copolymers are not only available as block of an aliphatic conjugated diene such as those for the formation of molded articles by Isoprene, methylisoprene, butadiene and mixed poly- 60 Injection molding, compression molding, extrusion molding, for the merisate of styrene butadiene. The final formation of films, for spraying on coatings, Blocks, which are the non-elastomeric blocks, are useful for making adhesives, but rather which the polymers the special self- also for the production of latices and improvement hardening properties are derived from alkenyl- the properties of other elastomeric products and Substituted aromatic hydrocarbons are suitable for 65 plastics. The block copolymers are forms. These are preferably vinyl-substituted ones, for example of particular use for aromatic purposes Polymer blocks and, even better, an improvement in the processability of certain synthetic or several monovinyl-substituted aromatic rubber rubbers, in particular of elastomers

7 8

Homopolymers and non-uniform olefinic and the polymerization continued until the complete VerMischpolmerisaten from including mono- and use of the monomeric isoprene. Afterwards diolefins, as well as of polymers of conjugated divinylbenzene was added and the Kupplungsten Serve responsive to special purpose of increasing at 5O ⁰ C. The response became its wet cast strength properties. This is finished from 5 by adding alcohol,
of particular importance when the block mixed poly-

merisate in an amount of 5 to 50 percent by weight, a e e l

based on the total rubber content. Production of symmetrical block polymers

The block polymers can be mixed with olefin resins such as * jy p _o i _vs tvrol 0193

Polyethylene, polystyrene, polypropylene or ethylene- io _M polystyrene 32 * 500

propylene mixed to increase their tensile _M ^ _existing "" _a Kiiver '' ion 'to'

strength and other properties are combined. Polymerization of isoprene 0.00206

The inventively Blockmischpoly- _{mol DVB} produced _{after the} p _o i _ymerisa tio _n

Merisate is not only characterized by a low _{yon Is for wasQ QmM}

Glass transition temperature of their middle elastomeric 15 Finally IV 1 63
Section and due to the relatively high glass transition temperature of their terminal non-elastomeric blocks * intrinsic viscosity.

but also by their intrinsic viscosity. In Table 2 below, the stress reliever will usually be in the range of about 0.7 to 5.0 elongation properties of the resulting coupled. The polymers have an average ao polymer shown.
Molecular weight of preferably about 75,000
up to 500000. Table 2

The glass transition temperature can be based on dilato-stress-strain properties

determine metric way. A treatise on these symmetrical block polymers

Rubber "(1954), pp. 356-360.

The production of coupled block copolymers and their use in rubber preparations is explained in more detail by the following examples.

example 1

In 1600g benzene at a temperature of 5O ⁰ C 100 g of styrene were dissolved, and then 0.003 mol of secondary butyl lithium added. The polymerization was carried out at approximately 50 ^° C. in a reaction vessel until all of the styrene had been converted into a polymer of an intrinsic viscosity according to Table 1. 300 g of isoprene were then added to the reaction mixture

at 140 C for 5 minutes

% Modulus, kg / cm ² 18.3

% Modulus, kg / cm ² 30.9

Elongation at break,% 900

Tensile strength, kg / cm ² 198

Set,% 5

Example 2

Under the conditions according to Example 1, two coupled block copolymers were produced, however, 0.0035 moles of secondary butyllithium and various amounts of divinylbenzene were used for the coupling stage. In table are the results related to these Block polymerizations compiled.

Table 3
Block polymers produced by coupling with divinylbenzene

sample IV ^a ) Styrene
(Mv IO- ⁵ ) IV Styrene-isoprene block
(% Sty) Mv ΙΟ- ⁵ Divinyl
benzene stoech. SI-IS-
IV block
MvIO- ⁶ A. 0.158
0.172 24
27.5 1.02
0.79 31.0
22.5 190
120 2
10 1.74
1.42 400
265 B.

^a ) IV = intrinsic viscosity.

Table 4 shows the stress-strain properties obtained with these block polymers were obtained.

Tabel

Physical properties of block copolymers coupled with divinylbenzene
5 minutes at 140 ⁰ C, pressed sheets, micro-punching blade, 23 ⁰ C, 1.2 "/ minute

PIN 176

A2

Bl

B2

300% modulus, kg / cm ² 2.95

500% modulus, kg / cm ² 5.20

Elongation at break

Tensile strength (%), kg / cm ² 15.8

Set

^x ) Refers to a styrene-isoprene block polymer before coupling. ^s ) Refers to coupled block polymers.

12.9
27.4

950

175.8
18th

1.48
1.97
1250
6.68

12.9 20.7 1080 263.6 10

ίο

Example 3

To maintain coupled block polymers of widely differing molecular weights Terminal (polystyrene) and central (polyisoprene) blocks underwent a series of block polymerizations carried out with inserted coupling stage. Furthermore, the solvents varied from benzene to Cyclohexane. Twice the stoichiometric amount of divinylbenzene was used. In Table 5 are the Results in connection with the molecular weight of the coupled block copolymers obtained compiled.

Tabel

Molecular Before the coupling Molecular τχτ After coupling solvent weight · ίο- ³ Block 1 weight · ίο- ³ JLV 61 167 1.2 JM ΟΠ. 34 56 0.57 2.1 benzene Sty 24 63 0.71 0.95 Cyclohexane Sty 21 46 0.85 1.38 benzene Sty 25th 127 1.0 1.34 Cyclohexane Sty 1.8 Cyclohexane Sty Mon ip I IP BD BD IP

Claims (1)

Claim: Process for the production of an elastomeric block copolymer by multistage polymerization, wherein in the first stage an alkenyl as substituted aromatic hydrocarbon in a hydrocarbon solvent in the presence of a lithium-based catalyst Formation of a block product A - Li, the Α component of which has an average molecular weight between 2000 and 100000 is polymerized and a conjugated in the second stage Added diene hydrocarbon and the polymerization with the formation of an intermediate block copolymer of configuration A - B - Li, whose B component has an average molecular weight has between 5000 and 200000 is continued, characterized in that that in the third stage at least two of the A-B copolymer blocks by adding one dialkenyl-substituted aromatic hydrocarbon couples together and then the reaction is terminated in a manner known per se by adding a chain terminator. Considered publications:
German interpretative document No. 1144 484. 709 617/557 7.67 © Bundesdruckerei Berlin