DE1595170C - Method for preventing the cold flow of cis-polybutadiene elastomers - Google Patents

Description

In the last few years, research was done considerable efforts aimed at producing improved rubber-like polymers. Here acquired polybutadiene in a high percentage, i.e. H. at least 85% cis-1,4 addition, due to its superior properties received widespread attention. As such, this polymer is particularly suitable for Manufacture of automobile and truck tires and other items suitable for previously the usual synthetic polymers and natural rubbers were preferred. In the preparation of and processing of eis-polybutadiene occurred due to its tendency to cold flow (3 in unvulcanized state presents considerable difficulties. For example, if there are cracks in the packaging or holes occurred, the polymer flowed out, resulting in contamination or loss of product, Gluing the packs together and the like.

The process for preventing the cold flow of cis-polybutadiene elastomers, which have been prepared by polymerizing 1,3-butadiene by known processes in the presence of known stereospecific organometallic mixed catalysts, is characterized in that a halogenated olefin is added to the polymerization mixture before the catalyst is inactivated or a halogenated ether which carries at least two active halogen atoms in the position to the double bond or to the ether oxygen atom and where the olefin or the ether contain up to 20 carbon atoms per molecule, and the mixture is added for 5 minutes to 5 hours at a temperature in the range holds from about -7 to about 12O ⁰ C.

The obtained cis-polybutadiene retains its desirable physical properties and also has better resistance to cold flow in the unvulcanized state.

A group of organic reactive substances which can be used according to the invention are halogen-containing olefins which contain at least two active halogen atoms, d. H. at least 2 | Ia | ogen atoms, the are bonded to carbon atoms which are in -position to a doubly bonded carbon atom. The active halogen atoms can be bonded to the same or to different carbon atoms in the molecule. the Compounds can contain up to 20 carbon atoms per molecule and can be partial or be fully halogenated. "Olefins", which can also be cyclic in nature, are not intended here only monoolefins but also diolefins are understood. The active halogen containing compounds can contain fluorine, chlorine, bromine or iodine or mixtures of these halogens. However chlorine, bromine and iodine are preferred, especially compounds containing chlorine. The halogen-containing Compounds can have various hydrocarbon substituents, such as alkyl, cycloalkyl, Contain aryl, aralkyl or alkaryl groups. Such active halogen-containing compounds to consist of carbon, hydrogen and halogen atoms.

Specific active halogen-containing compounds of the group indicated which can be used in the execution of the invention ^(> 5 are, for example, the following:
Hexaehlorpropene,
3,3-1) ibromo-1-chloro-1 -propene,

I ^ -Difluor ^ -bulcn,

1,4-diiodo-2-pentene,

1 ^ -Dichlor ^ -hcxen,

4,4-dichloro-2-heptene,

lJJ ^ X-hexachloro-iri-octadiene,

2.5: dibromo-l, 6-diphenyl-3-hexene,

1J, 1 A ^ Pcntachlor-.Vüthyl ^ -pentcn,

Hexachlorocyclopentadiene,

.l ^ Ao-tetrabromo-M-cyclohexadicn,

3,6-difluoro-1-cyclohexene,

Octachlorocyclopentene.

In practicing the invention, the active halogen-containing compound is used either as such or added as a solution to the unquenched solution of the polymer. Under “not deterred Polymer "is understood to mean a polymer that has not yet been used with any type of reagent Inactivation of the catalyst treated '. Suitable solvents for the active halogen containing compound are e.g. B. the substances used as diluents in the manufacture of cis-polybutadiene be used. Such solvents are well known to those skilled in the art. After completion The treatment agent is added to the polymerization and agitating the mixture to facilitate contact of the reagents. The temperature can either before or after the treatment agent has been added, as required.

The reaction of the halogenated olelin with the unsquenched ice-polybutadiene solution can be carried out at a temperature between about -7 and about 120.degree. C., preferably between about 15 and 80.degree 'will. The treatment time depends on both the temperature and the one used halogen-containing compound. In general, it ranges from 5 minutes to 5 hours.

Another group of suitable devices organic reactive substances consists of ethers, the at least two active I lalogenatome which are bound to carbon slolf atoms which are in -position to the ether oxygen stand.

The ethers added according to the invention have the following general formula:

C O

wherein X is hydrogen or halogen amines, saturated aliphatic hydrocarbon radicals, saturated cycloaliphatic Hydrocarbon residues, aromatic hydrocarbon residues, halogen-substituted saturated ones aliphatic radicals, halogen-substituted saturated ones cycloaliphatic radicals and halogen-substituted aromatic radicals and R saturated aliphatic hydrocarbon radicals, saturated cycloaliphatic hydrocarbon residues, aromatic hydrocarbon residues, halogen-substituted saturated aliphatic radicals, halogen-substituted saturated cycloaliphatic radicals, halogen-substituted aromatic radicals and radicals of the formula

mean and which contain at least 2 halogen atoms, the carbon atoms that are close to the ethereal oxygen. The wire connection can Contain up to a total of 20 carbon atoms per molecule and can be partially or fully halogenated being. Mixtures of the various halogenated ether compounds can also be used will. The active halogen-containing compounds can be fluorine, chlorine, bromine or iodine or Contain mixtures of these halogens. However, chlorine, bromine and iodine compounds are preferred, especially chlorine-containing compounds. Since the ether compounds contain at least 2 halogen atoms must, which are located on carbon atoms in the -position to the ether oxygen, they are in the hereinafter referred to as «-halogenierle ether.

Specific examples of α-halogenated ethers used in the practice of the invention can be the following:

Bis (chloromethyl) ether,

Bis (l -bromüthyOether,

Methyl dichloromethyl ether,

Bis (1 -nuorpropyOüther,

Chloromiethyl-1-chloropropylate.

Bis (l-iodopentyl) ether,

Bisil-chlordecyOälher,

Hexyl-U-dichloroheptyl ether

1 -Chlor-n-Bul} 1-1,1 -dichlor-n-butylether,

Bis (1,1-clibromdecyDäther,

1, I -Difltioräthyl-1 -fluorheptyläther,

Bis [I-bromo (2-iühyi) butyl weed ether,

Dillion methyl l-fluoropropyl ether,

, l-dibromohexyl-lJ-dichlorodecyl ether.

, l-dichloropropylcyclohexyl ether.

-Chlor-1 -bromobutylphenyl ether,

, l-diiodopentyl-4-chlorobenzyl ether,

,!,. VTiichlorhexyl .Vchiorcyclohexylether.
Bis (trichloromethyl) ether,
Bis (dichlorophenylmethyl) ether,
Bis [difluoro (4-lolyl) methyl] ether,
, l-chloro-l-bromo-.Vphenylpropylhexachlor-

phenyl ether, <..

U-dichlorobutyl-KM-lrichlor-.Vn-propyl-7-phenylheptyl ether.

The implementation of the -halogenated ether with the solution of the non-quenched ice-polybutadiene can be at a temperature in the range from about -7 to about 120 C, preferably -7 to 80 C, be performed. The treatment time depends on both the temperature and the one used «-Halogenated ether. It is in the range of 5 minutes for mixing the -halogenated Ether treatment agents with the polymer solution are required up to 5 hours. If the polymerization temperature is above about -7 C, you can often get satisfactory results with A treatment time of 5 minutes when the temperature is at that used for the polymerization Height is maintained. In other cases, depending on the desired results, a longer treatment time at higher temperature is preferred.

The amount of halogenated olefin or halogenated Ether used to reduce the cold flow of cis-polybutadiene, is based on the organometallic component of the catalyst. It is generally in the range from 0.05 to 10 mmoles per mole of organometallic compound.

The polybutadienes can be prepared by polymerizing butadiene with a catalyst system which is formed by mixing substances which contain an organometallic compound and iodine, the latter being added in the free or bound state. Such a polymerization system provides a cis-polybutadiene which has superior physical properties in the vulcanized state, but in the unvulcanized state has a tendency to cold-flow if the treating agent is not added. The term "cis-polybutadiene" is used here in the sense that it is understood to mean _{a polybutadiene with at least 85 "/ (} > cis-1,4 addition, ie between 85 to 98 ¹ V _{1, and more} Examples of preferred catalyst systems which can be used for the polymerization of 1,3-butadiene to form an cis-1,4-polybutadiene are given:

Triisobutylaluminum and titanium tetraiodide, triisobutylaluminum, titanium tetrachloride and titanium tetraiodide,
Zinc diethyl and titanium tetraiodide, triisobutyl aluminum, titanium tetrachloride and iodine, triisobutyl aluminum, titanium tetrachloride and 1,4-diiodo-2-butene.

The polymerization process for the production of ίο cis-polybutadiene is generally carried out in the presence run of a hydrocarbon diluent, which is harmless to the catalyst system is. Examples of suitable diluents are /. B. aromatic, paraffinic and cycloparaffinic Hydrocarbons.

In the polymerization of 1,3-butadiene to one

cis-polybutadiene is the amount of organometallic .nischer Compound used for the preparation of the catalyst composition in general in the range from 0.75 to 20 mol per mole of halogen-containing catalyst component, d. H. one Metal halide with or without a second metal halide or elemental iodine. The concentration of the total catalyst composition, i.e. H. from organometallic compound and halogen-containing catalyst component is usually in the range from 0.01 to K) percent by weight, preferably in the range from 0.01 to 5 percent by weight, based on the total amount of 1,3-butadiene charged to the reactor system.

After completion of the polymerization reaction, the organic compound, the at least two contains active halogen atoms which are attached to carbon atoms are bonded in the «position to a doubly bonded carbon atom or a Stand ether oxygen atom, added to the polymerization mixture. The mixture is then thorough moved to ensure contact of the reagents. After completing this stage, the reaction mixture is then treated to inactivate the catalyst and recover the polymer. The inactivation step can be carried out in any of the known ways. A suitable one One method of inactivating the catalyst is to add an alcohol.

For a better understanding of the invention, two preferred embodiments are given in the following examples explained.

B c i s ρ i c 1 I

The following approach was used to produce ice-polybutadiene uses:

Toluene, parts by weight KK) O

1,3-butadiene, parts by weight ..... 100

Triisobutylaluminum, mhm ¹ ) ... 3.76

Iodine, mhm ¹ ) 0.9

Titarite trachloride, mhm ¹ ) 0.447

Temperature, C .. 5

Duration, hours 3

') Millimoles per 100 grams of 1,3-butadiene.

The toluene was added first, then the reactor was purged with nitrogen *. Butadiene and then triisobutylaluminum. Iodine and titanium tetrachloride were added. A series of five Approaches was carried out. After 3 hours of polymerization, each of two batches was used with 2 mmol of a different halogenated organic Treated compound, one with hexachlorocyclopentadiene and the other with Hexachloropropane. One batch was saved for comparison; i.e. no halogenated c organic reagent compound added. All three polymerization mixtures were then brought to 70 ° C heated, and stirred at this temperature for 15 minutes. Then were hexachlorocyclopentadiene and Hexachloropropene added in amounts of 2 mmol each to each of the other two approaches, and the mixtures were stirred for 30 minutes, the temperature being lowered to 5 ° C. Then became a solution of 2,2'-methylene-bis (4-methyl-6-tert.-butylphenol) in isopropyl alcohol is added to each of the batches in an amount sufficient to about 1 part by weight of antipxydant per 100 parts by weight Supply rubber. Then the polymers were coagulated in isopropyl alcohol, separated off, dried and the cold flow determined. The following results were obtained:

Treatment of the polymer

approach

Halogenated organic Reagent compound

none

Hexachlorocyclopentadiene

Hexachloropropene

Hexachlorocyclopentadiene

Hexachloropropene

Temperature C

7 «

70

70

Treatment duucr
Minutes

15th
15th
15th
30th
30th

Monomer conversion ')

88.3
81.6
78.3
84.2
90.3

Cold flow ² )
mg / min

8.31
■ 2.96

4.97
2.13

¹ I Calculated from the weight of the product obtained.

^:) The flow rate is determined by extrusion of the rubber through a nozzle (> .. 15 mm diameter at 0.25 kg under pressure and a temperature of 50 C. After waiting 10 minutes until the equilibrium has been reached the

Strangpreßgcschvindigkeil determined and given in mg min.

B e i s ρ i c I 2

The following approach was used to produce eis-polybutadiene:

Toluene, parts by weight KKK)

1,3-butadiene. Parts by weight 100

Triisobutyl aluminum. mhm ¹ ) 2.3

Iodine. mhm ¹ ) 0.8

Titanium tetrachloride, mhm ¹ ) 0.4

Temperature. C 5

Duration. Hours 0.5

¹ liter millimoles per 100 grams of butadiene. _so

First the toluene was stirred in, then the reactor was purged with nitrogen and butadiene and then triisobutylaluminum, iodine and titanium tetrachloride were added. Two approaches were taken. In each run, a sample was prepared by a $> polymerization time of 0.5 hours, removed, and cold flow, and conversion were determined. 8 mmol per KK) g of butadiene bischloromethyl ether used were added to the remainder of batch 1, and the mixture was stirred for 30 minutes while the temperature was kept at 30 ° C. One part by weight of 2.2'-meth \ enebis (4-methyl -6-tert-butylphenol) dissolved in a mixture of equal volumes of isopropyl alcohol and toluene per KK) parts by weight of polymer are added. <· 5 whereupon the polymer is coagulated in isopropyl alcohol, separated off and dried: the cold flow and conversion were then determined again. The final conversion was calculated from the weight of the product recovered. After the first part of batch 2 was removed. the remainder was heated to 30 ° C. for 30 minutes with stirring. The polymer was then obtained as in batch I. and cold flow and final conversion were determined. The following results were obtained:

4--

Conversion. "". 0.5 hours ...! 51

Cold flow. mg min

originally

after treatment with

Bis (chloromethyl) ether

after 3 () minutes of heating at
30 C

Final conversion

2.8
0.04

85

50
2.3

0.83 97

These results show that through help treatment only a reduction in the cold flow was obtained, but this effect not even close was as pronounced as in the seed / in which the solution of the non-quenched polymer with BislchloromethyDether has been treated.

Claims (2)

Patent claims: 1. Procedure / ur prevention of cold flow \ tin cis-polybutadiene elastomers. do through PoIv- merization of 1,3-butadiene by known processes produced in the presence of known stereospecific organometallic mixed catalysts have been, characterized in that the polymerization mixture prior to inactivation of the catalyst, a halogenated olefin or a halogenated one Ether, the at least two active halogen atoms in α-position to the double bond or to the ether oxygen atom carry and wherein the olefin or the ether has up to 20 carbon atoms per molecule contain, adds and the mixture 5 minutes to 5 hours at a temperature in the range from about -7 to about 120''C. 2. The method according to claim 1, characterized in that the reaction mixture 0.05 to 10 mmoles of the olefin or ether per mole of that used to form the polymerization catalyst organometallic compound used.