DE1031969B - Process for the bromination of solid, plastic isoolefin-polyolefin copolymers - Google Patents

Description

The invention relates to a novel improvement in the process for producing brominated isoolefin-polyolefin copolymer derivatives and especially the bromination of isoolene-polyolefin copolymers with bromohydantoins.

US Pat. No. 2,631,984 describes brominated isoolefin-polyolefin copolymers and processes for their preparation. Among the processes described in this patent is a "dry process " in which a solid brominating agent, such as N-bromoacetamide, is mixed with the appropriate copolymer in a roller mill and heated. Although the process is suitable for producing the desired brominated derivative, it has been found that the process is very disadvantageous because of scratching and corrosion of the surfaces of the mixing rolls, so that it cannot be used on an industrial scale. Furthermore, high temperatures and longer heating times are required in order to fully develop the brominated derivative, which aggravates the corrosion of the roll surfaces.

It has been found that significant improvements can be achieved by using the bromohydantoins known as brominating agents for the bromination of isoolefin-polyolefin copolymers by the "dry process". The improvement of the " dry process" consists in adding a bromohydantoin to the desired isoolefin-polyolefin copolymer in a mill or an internal mixer, intimately mixing the two and then heating the resulting mass in a device other than the mixing apparatus so that the copolymer derivative after initial mixing process is developed. It has also been found that the bromohydantoins among the solid brominating agents for this type of bromination have unique properties in terms of ease and uniformity of distribution and in that they do not corrode the surfaces of the mixing equipment when mixed with the appropriate isoolefin copolymer at normal mixing temperatures cause in the range of 38 to 57 ° C or even higher temperatures. If N-bromoacetamide or N-bromosuccinimide is mixed with butyl rubber at this normal mixing temperature or even at lower temperatures in a mill, the surfaces of the rolls will be corroded after only a short time, even if the rolls are kept cool by suitable cooling devices. Another unexpected advantage that arises from the use of bromohydantoins as solid brominating agents for isoolefin-polyolefin copolymers is the high speed with which the brominated copolymer is developed at higher temperatures, these agents here being faster than N-bromoacetamide

for bromination stronger, more plastic
Isoolefin-polyolefin copolymers

Applicant:

The BF Goodrich Company,
New York, NY (V. St. A.)

Representative: Dr.-Ing. H. Ruschke, Berlin-Friedenau,

and Dipl.-Ing. K. Grentzenberg, Munich 27,

Pienzenauerstr. 2, patent attorneys

Claimed priority:
V. St. v. America May 3, 1954

Richard Thurl Morrissey, Cuyahoga Falls, Ohio

(V. St. A.),
has been named as the inventor

act and thereby the process can be effected at lower temperatures. Since the bromination of the Isoolefm-polyolefin copolymer mixed with bromohydantoins obviously does not occur at ordinary mixing temperatures, the mixture can are produced in a single operation at a temperature below 77 ° C and preferably below 66 ° C, and at a later time the brominated derivative is developed as desired. This improvement is very advantageous in the production on a large scale, since there are processes that are more economical and one better control of the manufacture, planning and use of equipment and a uniform product enable. It can e.g. B. the stable mixture of bromohydantoins and copolymer in one Operation mixed and stored or delivered as a permanent mixture, with the brominated derivative as needed or desired is developed. A main persistent approach can similarly be made which contains a large proportion of the bromohydantoin in the copolymer, and it can be used up to stored and then more effectively with an

809 530/447

3 4

'sufficient amount of the copolymer mixed. Any N-bromohydantoin can be used in the process of this

so as to obtain an end product which can be used according to the invention. The N-bromohydantoins

Heating has the desired bromine content. The following formula is used for verbs:

use of the usual solid brominating agents

the bromination of the copolymer begins in the 5R

Grinder and apparently sits down during storage

continued, resulting in a deterioration of the product an O = C C R

occurs. -! '■

Unexpectedly, it was found that the bro- χ - ^ ₃ ^ ^

mation process with bromohydantoin in the presence of io 2

Carbon black can be caused. That is most beneficial, C

as it is difficult to obtain panels of uniform thickness from the! ■

Obtain bromohydantoin copolymer mixture; O the thin parts of the board receive too much heat, and
the thicker ones are not heated effectively enough, and 15

is not a uniform derivative with reproducible In this R are hydrogen and alkyl radicals and '

Properties obtained when the panels do not contain an X hydrogen and bromine. Mono- and dibromo-

have uniform strength. When using carbon black (1,3-bromine) alkylhydantoins, in which the water

this will ease this problem. It represents amounts of substance or alkyl radicals that are about 1 to 8 carbons 5 to 100 parts by weight used, amounts containing 20 material atoms and at least one R being alkyl.

from about 10 to 50 parts are preferred. 1,3-Dibromo-5,5-dimethylhydantoin is particularly popular

Any type of carbon black is suitable, including the preferred. N-bromo-5,5-dimethyl-

called furnace and sewer soot. If large amounts of carbon black hydantoin, N-bromo-5-methyl-5-ethylhydantoin, 1,3-di-

Are present in the mixture, it may be desirable to bromo-5-methyl-S-ethyl-hydantoin, 1,3-dibromohydantoin be the amount of bromohydantoin up to about 25% 25 and 1,3-dibromo ~ 5-methylhydantoin. Dibromohydantoins

the increase normally applied. A fine and low molecular weight are preferred,

Particulate silicon oxide, such as any by heating The amount of bromine that is formed during the heating

(Electric arc or combustion) that the silicon stage that is created reacts with the copolymer depends on the

oxide, and dried, finely divided silica gel low amount of the bromohydantoin present and in one In place of a part or the whole, lesser amounts of the heating time and temperature can be suggested

amount of soot to be applied. It'll be starting. With the same other factors, an appropriate

finely divided silica and mixtures of silicon approximates rectilinear relationship between the original

and silica preferred. Concentration of the convertible bromine and the amount

During the bromination of the isoolefin-polyolefin mixture, the one present in the brominated copolymer

polymerisates will consist of new substances with unexpectedly excess bromine. The bromine content of the brominated

superior properties compared to bromine-free mixed poly copolymers can be quite precisely controlled by regulating

received merisats. This brominated, rubbery controls the concentration of the brominating agent

Isoolefin-polyolefin copolymers harden or become vulcanized.

Canize quite a bit even with vulcanizing agents. The brominated copolymers can be 0.5 fast, which is completely ineffective 40 percent by weight or 1 to 4, 8, 10 or 20 percent by weight with non-brominated substances, with the formation of vulcanized pro up to 50 percent by weight of bound bromine deducts, which hold those obtained from non-brominated materials, depending on the extent of which by far exceed. In addition, the unsaturation sticks, which in turn depends on the proportion of the polybrominated copolymer, in contrast to the non-olefins in the copolymer. The percentage of brominated substances, good in a wide variety of substances, 45 content of the bound bromine is lower than that of theory, including natural and synthetic rubber, and table for the bromination of all olefinic double bonds are valuable as adhesives. The required amount of bromine containing bromine; For the production of high-molar copolymers, natural rubber isoolefin-polyolefin copolymers with or the various synthetic rubbers with rubber-like properties, the iodine numbers of any desired ratio together - 5 ° less than 50 of the type of butyl rubber, can be mixed. To form the resulting mixtures, one prefers to set the percentage of bound post-vulcanization products with excellent bromine on the order of 20 to 80 ⁰ Z _{0 of} the properties. that would be present if all of the olefinic bonds were fully brominated on all of the isoolefinic double bonds. It is believed that polyolefin copolymers are used which are in the order of 1 to 8% ^and the percentage of bound bromine in these mixtures of the above-mentioned US Pat. No. 2,631,984. , for use as adhesives on the order of

In addition, any of the other known 1.5 to 4 ° / _0th

Isoolefin-polyolefin copolymers in this The time and the temperature that are necessary to

improved process for the production of brominated 60 the brominated copolymer from the isoolefin-poly-

Derivatives are used; so result e.g. according to olefin - copolymer - bromohydantoin - mixture to

This invention develops resinous copolymers with, depend on one another and can vary

low molecular weight, which may be with. The temperature must and can be above 77 ° C

Sulfur are not easily vulcanizable, reach suitable for short periods of time 150 ⁰ C and more. It

brominated derivatives. Similarly, it has been found to be more advantageous that a polymerizate is light in color

wise isoolefin-polyolefin copolymers, the other by developing the brominated derivative in a

copolymerized monomers, such as styrene, chlorostyrenes, as low a temperature as possible is produced. the

Alkyl styrenes, acrylic chloride, methallyl chloride, and other optimal heating times and temperatures

contain monoolefinic monomers, for the production of thin materials with a thickness of about 3.2 mm,

brominated derivatives. 70 from the copolymer and 1,3-dibromo-5,5-di-

methylhydantoin exist in an oven 60 to 30 minutes at temperatures between about 99 and 113 ° C. By heating for 60 min at 100 ° C for 30 minutes or heating at 113 ⁰ C a mixture of 6 parts of 1,3-dibromo-5,5-dimethylhydantoin and the copolymer is z. B. made a preferred material.

The time and temperature of the heating of the mixed polymer / bromohydantoin mixtures can be varied considerably. As stated above, it was found that a temperature above 77 ^° C. is necessary in order to develop a brominated product. Useful products are e.g. B. by 20-, 30, - 60-, 90- and even 120-minute heating at 100 ⁰ C and also z. B. obtained by 5-, 10-, 20-, and even 40 minute heating at 138 ⁰ C. Although the optimal product is developed at the desired lower temperature, if the product is developed in shorter times and at higher temperatures, e.g. B. at temperatures above 150 ° C in times of less than 5 minutes, also obtained suitable products. Usually, heating times of about 120 minutes or less at temperatures of about 98 to 150 ^° C. cause useful products to be formed. The combination of the lowest temperature and the shortest heating time is desirable. Usually this will be at 20 to 90 minutes and at about 98 to 12O ⁰ C, with longer times for thick materials and shorter times are required at higher temperatures. Mixtures that are briefly ^{heated above 150 °} C. must be monitored more closely; the products obtained at a lower temperature are more pliable and give more uniform products. Continuous processes in which the material is quickly ^{heated to over 150, 180 °} C. for short times are particularly valuable.

Of course, if appropriate, the brominated derivative can be added to the mixing apparatus after mixing also be developed by heating; however, this is preferably carried out as a separate step.

Practice and certain preferred embodiments of the invention are shown in the following Examples shown. Unless otherwise noted, parts are parts by weight.

Example I.

100 parts of an isobutylene-isoprene copolymer consisting of about 97.5% isobutylene and about 2.5% isoprene are placed on a mixing roll mill and processed until a uniform sheet is formed on the roll. 5.4 parts of 1,3-dibromo-5,5-dimethylhydantoin are then added to the copolymer and the brominating agent is thoroughly incorporated into the copolymer. During the mixing time, cooling water is passed through the rollers to keep the processed mixture cool. The mass normally has a temperature between 40 and 50 ^° C. during mixing. After mixing, the mass is removed from the mixing mill. There is no noticeable attack by the brominating agent on the rolls, neither by discoloration nor by corrosion. This should be compared with a corresponding amount of N-bromoacetamide in a larger amount of the same copolymer under the same conditions. In this case, when the mass is removed from the mixing mill, corrosion is observed due to a brown rust-like discoloration of the mill rolls. If the mixing with N-bromoacetamide is continued, the rollers will be severely corroded, and scratches and scoring will occur. As has been observed, this is not the case when bromohydantoins are used as brominating agents.

Examples II to IV

In order to illustrate the valuable products according to the invention, brominated derivatives are prepared according to the method of Example I. Varying amounts of 1,3-dibromo-5,5-dimethylhydantoin are rolled into the copolymer of Example I, whereupon the product is placed in an oven at 138 ° C. for 10 minutes in order to develop the brominated copolymer derivative. The brominated copolymers are then mixed according to the following procedure and ^{cured at 150 °} C. for the specified time.

Material parts

_1S brominated copolymer 100.0

Carbon black 50.0

Zinc oxide 5.0

Stearic acid 3.0

Mercaptobenzothiazole 0.5

Tetramethylthiuram disulfide ·. 1.5

Sulfur 2.0

Example II

1.35 parts 1,3-dibromo-5,5-dimethylhydantoin (0.75% bromine in the copolymer)

Time 300 ° / ₀ module Tear
strength strain 30 10 Minutes 19.6 kg / cm ² 173.6 kg / cm ^a 840% 20th Minutes 35.0 kg / cm ² 197.8 kg / cm ² 775% 30th Minutes 35.0 kg / cm ² 189.0 kg / cm ² 725% 45 Minutes 45.5 kg / cm ² 196.0 kg / cm ² 650% 75 Minutes 61.5 kg / cm ² 196.0 kg / cm ² 600% 35 90 Minutes 61.5 kg / cm ² 196.0 kg / cm ² 560%

Example III

2.70 parts of 1,3-dibromo-5,5-dimethylhydantoin (1.50% bromine in the copolymer)

Time 300 ° / "module Tear
strength strain 45 10 minutes
20 minutes
30 minutes
45 minutes
75 minutes
50 90 minutes 21.0 kg / cm ²
24.5 kg / cm ²
31.5 kg / cm ²
31.5 kg / cm ²
38.5 kg / cm ²
45.5 kg / cm ² 151.5 kg / cm ²
162.5 kg / cm ^e
182.0 kg / cm ²
164.0 kg / cm ²
192.5 kg / cm ²
196.0 kg / cm ² 840%
800%
750%
700%
715%
625%

Example IV

5.40 parts 1,3-dibromo-5,5-dimethylhydantoin (3.0% bromine in the copolymer)

Time 300% modulus Tear
strength strain 6o 10 Minutes 56.0 kg / cm ² 183.5 kg / cm ² 650 o / _o 20th Minutes 50.5 kg / cm ² 178.5 kg / cm ² 600% 30th Minutes 50.5 kg / cm ² 178.5 kg / cm ² 650% 45 Minutes 50.5 kg / cm ² 180.5 kg / cm ² 600% 75 Minutes 35.0 kg / cm ² 180.5 kg / cm ² 600% 65 90 Minutes 50.5 kg / cm ² 182.0 kg / cm ² 625 o / _o

Within a wide concentration range of

Bromhydantoins are useful products.

If these examples are repeated with other N-bromodialkylhydantoins, z. B. 1, S-dibromo-S-methyl-S-isobu-

tylhydantoin, excellent results are obtained in the same way.

Examples V and VI

To explain the use of the process at lower temperatures, 100 parts of a copolymer of 97.5 o / _o isobutylene and 2.5% isoprene are intimately mixed with 4, 6, 8 and 10 parts of 1,3-dibromo-5,5- dimethylhydantoin mixed in a mixer at a temperature of 38 to 50 ° C, after which the mixture 60 minutes, heated in an oven to a temperature of 100 ⁰ C long. Parts of the products prepared with 6 and 10 parts bromohydantoin are mixed according to the following protocol and cured at 153 ⁰ C.

Fabric parts

Brominated copolymer 70.0

Natural rubber 30.0

Epoxidized fatty acid ester 1,4

Heptylated Diphenylamines 1.0

Carbon black 35.0

■ zinc oxide 5.0

Plasticizer oil 10.0

Stearic acid 1.5

Di-o-tolylguanidine 0.1

Benzothiazyl disulfide 1.0

Sulfur 2.0

Prescription mixed with natural rubber and the mixture ^{cured at 153 0} C in the specified period of time.

Push parts

Brominated copolymer 70.0

Natural rubber 30.0

Epoxidized fatty acid ester 1,4

Heptylated Diphenylamines 1.0

Carbon black 35.0

Zinc oxide 5.0

Plasticizer oil 10.0

Stearic acid 1.5

Mercaptobenzothiazyl sulfide 1.0

Di-o-tolylguanidine 0.1

Sulfur 2.0

Time

10 mins
20 minutes
30 minutes
45 minutes
75 minutes

300% modulus

40.2 kg / cm ²
56.0 kg / cm ²
59.5 kg / cm ²
61.2 kg / cm ²
56.0 kg / cm ²

Tensile strength

115.5 kg / cm ² 141.5 kg / cm ² 147.0 kg / cm ² 138.0 kg / cm ² 127.0 kg / cm ²

strain

575 o _{/ o} 800% 850 o / _o 875 o / _o 800 o / _o

Example VIII

Example V 6 parts of bromohydantoin

Time 300% modulus Tear
strength strain 5 minutes
10 mins
30 minutes
45 minutes 21.0 kg / cm ²
57.5 kg / cm ²
67.5 kg / cm ²
73.5 kg / cm ² 48.0 kg / cm ²
141.5 kg / cm ²
149.5 kg / cm ²
146.5 kg / cm ² 625 Oj ₀
595 o / "
525 o / _o
495 o / _o

Example VI 10 parts of bromohydantoin To take advantage of the permanent blend of a bromohydantoin to show with the copolymer, will

The following results of the exposure test 30, a main batch of 42 parts of N-bromoacetamide with are obtained in the vulcanizates of the derivatives brominated with 6 and 10 parts of 58 parts of a copolymer of 97.5% isobutylene bromohydantoin. and 2.5% isoprene at 38 ⁰ C on a mixing roll mill

mixed, the temperature of the mass being about 58 ° C amounts to. During the mixing process, the mill rollers are severely corroded and small depressions are formed in the rollers and they will be discolored. On the other hand, if you mix 1,3-dibromo-5,5-dimethylhydantoin, the surfaces of the mill rollers do not corrode. The mixed raw materials are placed in polyethylene bags brought and left to age in the dark for 2 weeks. After that, the main approaches are with as much copolymer mixed to give a product having a content of about 3% bound bromine; it is heated to develop the brominated derivatives. The derivatives are made in accordance with regulations that apply to the given above are mixed. It turns out that the N-bromoacetamide approach itself within this short storage time a more than 10% loss of tensile strength suffers, while the bromohydantoin material does not lose its good properties during this aging period. It is believed that the N-bromoacetamide approach is brominated to a certain extent during the storage period and that the polymer in the absence a stabilizer added after the brominated derivative has been developed deteriorates shows leading to a general decrease in good physical properties in the final product contribute.

Example IX

100 parts of a copolymer composed of 97.5% isobutylene and 2.5% isoprene are applied to the rolling mill at 38 ° C brought and with 15 parts of an easily processable carbon black and 8 parts of 1,3-dibromo-5,5-dimethylhydantoin offset and intimately mixed. This creates a smooth, permanent plate of the raw materials of of uniform strength that can be stored and, when heated, a uniform, reproducible, provides brominated derivative with excellent physical properties. This procedure can be shared with others

Time 300% modulus Tear
strength strain 5 minutes
10 mins
30 minutes
45 minutes 22.4 kg / cm ²
54.3 kg / cm ²
75.5 kg / cm ²
79.8 kg / cm ² 55.5 kg / cm ²
127.5 kg / cm ²
123.0 kg / cm ²
124.5 kg / cm ² 620 o / _o
530 o / _o
435 o / _o
415%

This method of heating at lower temperatures can be applied and at temperatures as low as 93 ° C or 20 to 30 minutes at 113 ⁰ C, or shorter times at higher temperatures results in useful products to those described above with 4 and 8 parts bromohydantoin are equivalent.

Example VII

In order to explain the use of a monobromohydantoin in the process according to the invention, a brominated derivative prepared according to the method of Example I with 10 parts of N-bromodimethylhydantoin. Parts of the derivative are then according to the following

Amounts of soot or other types of soot, other amounts and bromohydantoins and other copolymers can be repeated in an internal mixer with the same excellent results.

From the foregoing description of the invention, it can be seen that the improved method of manufacture brominated isoolefin-polyolefin copolymers is a very useful and valuable process.

Claims (7)

PATENT CLAIMS: 1. A process for the bromination of solid, plastic isoolene-polyolefin copolymers by treating the copolymer with a bromine-releasing compound in an amount sufficient to bromine the copolymer up to a content of at least 0.5 percent by weight of bromine bound by addition, characterized in that the copolymer intimately mixed initially at a temperature below 77 ⁰ C temperature with N-Br omhydantoin as the brominating agent and then the mixture is heated in a different from the mixer apparatus so long to a temperature above 77 ° C temperature, as necessary for the development of the bromine-containing Mischpolymerisatderivates is . 2. The method according to claim 1, characterized in that the mixture is brought to a temperature for a time which is at least equivalent to ^{heating for 30 to 90 minutes at approximately 100 ° C.} 3. The method according to claim 1, characterized in that initially 2 to 10 parts by weight of a 1,3-dibromo-5,5-dialkylhydantoin with a rubber-like copolymer of 70 to 90 percent by weight isobutylene and 10 to 30 percent by weight isoprene at a temperature ^{below 77 ° C} lying temperature are intimately mixed and that the mixture is then ^{heated to a temperature of 93 to ISO 0} C for 120 to 5 minutes. 4. The method according to claim 1, characterized in that initially 2 to 10 parts by weight of 1,3-dibromo-5,5-dimethylhydantoin are intimately mixed ^{with a rubber-like copolymer of 90 to 99 percent by weight isobutylene and 1 to 10 percent by weight isoprene below 77 ° C} and that the mixture is then brought to a temperature and heated for a time equivalent to heating at 113 ° C for 30 minutes. 5. The method according to claim 1, characterized in that first 5 to 8 parts by weight of 1,3-dibromo-5,5-dimethylhydantoin with 100 parts by weight of a rubber-like copolymer of 97.5 ° / ₀ isobutylene and 2.5% isoprene at one temperature are intimately mixed below 65.5 ° C and that the mixture is then brought to a temperature of 99 to 121 ° C and heated for 60 to 20 minutes. 6. The method according to any one of the preceding claims, characterized in that the mixture is heated in the presence of carbon black or a finely divided silicon dioxide. 7. The method according to claim 6, characterized in that 5 to 100 parts by weight of carbon black are intimately mixed with the copolymer. References considered: U.S. Patent No. 2,631,984; Chemical Abstracts, Vol. 44, p. 4423h (1950), Vol. 47, .2708h (1953). © 809 530/447 6.