DE1189718B - Process for preventing the cold flow of unvulcanized cis-1,4-polybutadiene - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

C08d

German class: 39 c -25/05

Number: 1189 718

File number: P 30011IV d / 39 c

Filing date: August 14, 1962

Opening day: March 25, 1965

In recent years, significant research has been devoted to the preparation of improved rubbery polymers. As a result of the discovery of new catalyst systems, great strides have recently been made in this area. These catalyst systems are often referred to as "stereospecific" because they can polymerize monomers, especially conjugated dienes, into a certain geometric configuration. One of these products, which has received widespread attention due to its outstanding and excellent properties, is a polybutadiene which contains a high proportion, ie at least 85%, of cis-1,4-addition product. This high cis polybutadiene has physical properties that make it particularly useful in the manufacture of heavy duty tires and other articles for which conventional synthetic rubbers have been relatively unsatisfactory. In the processing of this polybutadiene with a high cis content, in particular in packaging, shipping and storage, considerable difficulties have been encountered, based on the fact that the polymer has a tendency to cold flow in the unvulcanized state. If z. If, for example, cracks or damage occur in the packaging used for storing the polymer, the polymer flows out of the packaging, and impurities and waste are obtained and the stacked packaging sticks together. The procedure for prevention Procedure for the prevention of cold heat
of unvulcanized cis-1,4-polybutadiene

Applicant:

Phillips Petroleum Company, Bartlesville,

OkIa. (V. St. A.)

Representative:

Dr. F. Zumstein,

Dipl.-Chem. Dr. rer. nat. E. Assmann

and Dipl.-Chem. Dr. R. Koenigsberger,

Patent Attorneys, Munich 2, Bräuhausstr. 4th

Named as inventor:

Gerard Kraus, Bartlesville, OkIa. (V. St. A.)

Claimed priority:

V. St. v. America August 21, 1961 (132538)

a Banbury mixer or similar kneading device. The mixing process is specified in the above Temperature and time range executed. Of course, the heating during the mixing pre-

the cold flow of unvulcanized cis-1,4-polygang take place, on the other hand, the substances can also Butadiene is characterized in that 100 g each are mixed and then heated in a separate step cis-1,4-polybutadiene with 0.075 to 1.75 mmol of one. After the treatment according to the invention organic peroxide or organic hydroper- the polymer is packaged and stored or used for oxyds, optionally in the presence of 0.015 to 1.2 g otherwise applied. The polymer Maleic acid or maleic anhydride and from 1 to 35 can be prepared by methods known to any person skilled in the art

, Heated for 10 g of zinc oxide, magnesium oxide or lead oxide at 120 to 18O ⁰ C.

This gives a product whose tendency to cold flow is significantly reduced and which has good processing properties having.

The heating is preferably at 150 to 160 ° C carried out. The heating time is short and depends on the temperature, although at higher temperatures shorter times are used. Which are mixed, processed and hardened.

As stated above, the peroxides used according to the invention are organic peroxides and organic hydroperoxides. The organic peroxides and hydroperoxides preferably contain between 4 and 40 carbon atoms per molecule and have one or more peroxide groups. aside from that the peroxides preferably used in carrying out the invention decompose at a

Heating time can range from 1 to 20 minutes at a moderately low temperature, i. H. at a temperature

There are, however, generally in the range of 5 to temperature in the range of 120 ° to 180 ⁰ C. for encryption

Be 10 minutes. The heating is applied in such a way that suitable peroxides can also pass through

controls that it reduces the cold flow, but each represent the formula R - O - O - R while

prevents substantial gel formation in the polymer. One of the hydroperoxides by the formula H - O - O - R

convenient method of treating the polymer in such a way that R is an acyl radical, a saturated one

your, consists in the incorporation of the additives in acyclic residue, an olefinically unsaturated acyclic

the rubber-like polymer on a calender, remainder, a saturated cyclic residue, an olefinically uns

509 520/445

can be a saturated cyclic radical or an aromatic radical , and this radical R can be substituted by a halogen, a hydroxyl group or an R'O group , where R 'has the meaning of R above . In addition, mixed compounds can also be used, ie organic peroxides in which one oxygen of the peroxide group is combined with a hydrocarbon group, e.g. B. an alkyl or cycloalkyl radical, while the other oxygen is connected to an acyl group . Peroxy compounds that represent half esters or diesters of dicarboxylic acids are just as applicable as monoperoxy compounds that are derived from dicarboxylic acids. Examples of suitable peroxides are: methyl-n-propyl peroxide, diethyl peroxide, ethylisopropyl peroxide, di-tert-butyl peroxide , dibenzoyl peroxide, dicrotonyl peroxide, dibenzyl peroxide, dicumyl peroxide, tert-butyl hydroperoxide and the tert-butyl hydroperoxide of peroxymaleic acid

ZO

[HOOC - CH = CH - CO - O ₂ - C (CH _{3) 3].}

In addition, peroxides can also be used which have been formed by the oxidation of terpene hydrocarbons such as pinane, α-pinine, p-menthane and turpentine .

The amounts of peroxide and maleic acid or maleic anhydride used are generally quite small. The amount of peroxide is preferably in the range from 0.15 to 1.00 mmol per 100 g of rubber. The amount of maleic acid or maleic anhydride is preferably in the range of 0.025 to 0.90 parts by weight per 100 parts of rubber. As stated above, in one embodiment of the invention, a third treatment substance, namely a metal oxide, is added to the cis-polybutadiene. This metal oxide can be incorporated into the rubber together with the peroxide and maleic acid or maleic anhydride , and the resulting composition can be heated as described above.

The amount of metal oxide used is preferably in the range from 2 to 8 parts by weight per 100 parts of rubber.

In addition to reducing the tendency of cis-polybutadiene to cold flow, the metal oxide also acts as a mild treatment agent when it is used together with a peroxide and maleic acid or maleic anhydride . It has been found that a cis-polybutadiene having a Mooney (ML-4 at 100 ⁰ C) over 30, that has in the range of about 35 to 60 excellent physical properties. However, such a cis-polybutadiene also exhibits considerable processing difficulties. If you z. If, for example, an attempt is made to extrude a cis-polybutadiene with a Mooney value of more than 30, which has been mixed according to the usual recipes, the extrusion speed is often unsatisfactorily low and the sides of the extrusion are rough. The usually applied in such polymers rolling temperature is around 110 ⁰ C, at which temperature the polymer tends to hang down also from the roll and is immovable. In addition , it is often difficult to mix carbon black into the polymer. A cis-polybutadiene has a low Mooney value (ML-4 at 100 ⁰ C) up, that is under 30, can be processed very easily. However, because of its excessive tendency to cold flow, the polymer is not entirely satisfactory. Treatment of this polymer with a peroxide or a peroxide and maleic acid or maleic anhydride reduces the cold flow, but has a disadvantageous effect on the processing properties compared to those of the starting polymer. It has now been found that the addition of metal oxide to the cis-polybutadiene of high or low Mooney values improves the processing properties of the polymer, e.g. B. good carbon black incorporation, rollability, extrudability and the like.

The invention is concerned with reducing cold flow in all types of cis-polybutadiene, i.e. H. cis-polybutadienes, which vary from low to high Mooney grades. While trying to solve this Other methods have been suggested to solve the problem, but discolor many of the agents used the polymer to an undesirable extent. One of the important advantages of the method according to the invention is that the treated polymer is light in color.

The invention can generally be applied to polybutadienes which contain a high proportion of cis-1,4-addition product. Here, a cis-polybutadiene is generally preferred that at least 85% cis-1,4-addition product, ie 85 to 98% ^{un £} i contains more. A process for the preparation of such a cis-polybutadiene is the subject of the earlier patent 1,162,089.

It has been proposed to reduce or reduce the tendency of cis-polybutadiene to cold flow essentially eliminated by using a compound that is a cis-polybutadiene of less Contains inherent viscosity and a polybutadiene with high inherent viscosity. A suitable mass consists of

A is a polybutadiene which is cis-1,4-addition product, trans-1,4-addition product and 1,2-addition product contains, wherein at least 85% of the polymer is formed by cis-1,4-addition and which has an inherent viscosity in the range of 0.75 to 3.0, and off

B a polybutadiene having an inherent viscosity in the range from 7 to 20, the amount from B to 40% of the weight A plus B.

This high inherent viscosity polymer can be a cis polybutadiene or it can be a polybutadiene with a low cis content, such as B. use an emulsion polybutadiene. This mass can be easily by mixing two polybutadienes of the type mentioned. Instead, this mass can also by a single polymerization reaction using any of those commonly used Catalysts added in a polymerization zone, so that initially the polymer with high inherent viscosity is formed, followed by the formation of a low viscosity polymer.

A more complete understanding is provided by the following illustrative examples which, however, cover the invention shouldn't limit.

The microstructure of each of the cis-polybutadienes referred to in the examples was by dissolving a sample of the polymer in carbon disulfide and forming a solution containing 25 g Contains polymer per liter of solution. The infrared spectrum of the solution (% transmittance) was then determined on a commercially available infrared spectrophotometer.

5 6

The percentage of the total product obtained had the following microstructure: trans-1,4 unsaturation was calculated according to the following equation. Micro structure, ° /

and units calculated: ε = -, where ε = extink-

^tc eis, (by difference) 95.7

cation coefficient (L · mol- ¹ · cm- ¹ ); .E = absorbance 5 trans 1.7

(log -y-); t = layer thickness (cm); c = concentration ^Vm y ^{1 2} > ⁶

(Moles of double bonds per liter). The extinction was I _n different samples of the cis polybutadiene were

determined at the 10.35 ^ band, and the extinction variable amounts of benzoyl peroxide and maleic anhydride

coefficient was 146 (L- mol- ¹ · cm " ¹ ). IO or maleic acid on a two-roll calender.

The percentage of total present mixes. This mixture was then 5 to 10 minutes

1,2 (or vinyl) unsaturation was observed at a temperature between 152 and 166 ° C in a

above equation using the 11.0 µ band press. The treated samples were

and an extinction coefficient of 209 (L x mole " ¹ x inherent viscosity, gel, cold flow and Mooney value

cm " ¹ ) determined. 15. Determined. The cold flow was determined in this and the

The percentage of all of the following examples present by extrusion of the rubber

cis-1,4 unsaturation was determined by subtracting the schuks at 0.245 kg / cm ² pressure and at a temperature

the above process, certain trans-1,4- and 1,2- (Vi temperature of 5O ⁰ C through a 0.635 mm mouthpiece overall

Measure nyl) unsaturation from the theoretical unsaturation. 10 minutes was waited for the

assuming one double bond per C ₄ unit in the 20 equilibrium state was reached, and then the

Polymers determined. Extrusion speed measured and the values in

". -Ii milligrams recorded per minute. This was done

Example 1 _e j _n control run made in which no treatment

A butadiene was added in the presence of a catalyst. The sets of loading

Sators made from aluminum triisobutyl, titanium tetra- 25 and the results obtained are in

chloride and titanium tetraiodide, polymerized. Table I shown below.

Table I.

Composition, parts by weight

cis-polybutadiene

Benzoyl peroxide

Maleic anhydride

Maleic acid

Time, minutes

Temperature, ⁰ C

Inherent viscosity

Gd, ° / o

Cold flow, mg / min

Mooney ( ² ) (ML-4 at 100 ⁰ C) ...

C ¹ ) 0.21 millimoles per 100 grams of rubber. (*) ASTM D-297-55 T.

These data show that the treatment of cis-polybutadiene of a Mooney value of 47 with benzoyl peroxide and maleic anhydride caused a substantial reduction in cold flow. Next became found that there was only a slight change in Mooney value.

The products of batches 1, 2, 6, 7 and 8 were mixed according to the following recipe:

cis polybutadiene 100

Highly abrasion-resistant furnace black 50

Zinc oxide 3

100 100 100 100 100 100 100 0.050) 0.05 0.05 0.05 0.05 0.05 0.05 0.15 0.60 0.15 0.30 0.60 - - - - - - - 0.15 0.60

Treatment conditions

10 10 5 5 5 10 10 152 152 166 166 166 152 152

Physical Properties

2.67 2.81 2.49 2.60 2.66 2.58 2.67 0 4th 0 0 0 0 0 0.4 0.4 0.9 0.5 0 0.4 0.5 52 51 - - - 53 52

60

65

Stearic acid 1

Disproportionate light rosin 5

Aromatic oil 5

Sulfur 1.75

N-Cyclohexyl-2-benzothiazole sulfenamide different

The masses were cured at 152 ° C. for 30 minutes and then determine the physical properties.

The results are shown in Table II. Table II

20)

v · 10 «( ⁸ ), mol / cm ³ ^) ... 300 ^e / ₀ module («), kg / cm »tensile strength ^), kg / cm *.

Strain("), %

Shore A hardness ( ⁵ )

Heat build-up (»), ΔΤ, ⁰ C .. elasticity), %

2.22

105

188.5

500 63 32.5 71.5 2.28

107

178

470
62
29.1
74.5

2.20

104

193

510
63
30.8
73.0

2.39

118

175.8

460 64 32.5 71.1

2.17 99.5

191

530 62 29.0 73.1

(*) Sulphonamide, 1.1 parts per 100 parts rubber.

(·) Sulphonamide 1.0 part per 100 parts of rubber.

(*) Determined using the Kraus swelling method, described in Rubber World, October 1946. This value indicates the number of actual cross-linking chains per unit of volume of rubber. The higher the number, the more the rubber is cross-linked (vulcanized).

( ⁴ ) ASTM D 412-71 T. Scott stretch machine L-6. The tests were carried out at 26.7 ⁰ C.

C) ASTM D 676-55 T. Shore hardness meter, type A.

(·) ASTM D 623-52 T. Method A, Goodrich Flexometer, 10.1 kg / cm ² load, 0.444 cm impact height. A circular cylinder 1.78 cm in diameter and 2.54 cm in height served as the test sample.

O ASTM D 945-55 (modified). Yerzley oscilloscope. A circular cylinder 1.78 cm in diameter and 2.54 cm in height served as the test sample.

The values show that the physical properties of the vulcanizates are similar to those of untreated cis-polybutadiene.

Example 2

Butadiene was polymerized with a catalyst consisting of aluminum triisobutyl and titanium tetraiodide. Table III shows the recipe used, the working conditions and certain properties of the product .

Table III

Parts by weight

1,3-butadiene 100

Toluene 1200

Aluminum triisobutyl 0.78 Titanium tetraiodide 0.56 Temperature, ⁰ C

Beginning -12

Control 4.5

Time, hours 5.3 Conversion,% 93 MooneyO (ML-4 at 100 ⁰ C) 17 Intrinsic viscosity 1.64

Gel, "/" 0

Cold flow, mg / min 13.5

( ^x ) See footnote ( ^! ) from Table I.

The polymer produced as described above had the following microstructure:

ice cream 92.8%

trans 4.2%

Vinyl 3.0%

Samples of the polymer were treated with benzoyl peroxide (0.1 part by weight per 100 parts of rubber) and variable amounts of maleic anhydride. The active ingredients were mixed on a two-roll calender and heated in a press at 152 ° C. for 10 minutes. Gel content, intrinsic viscosity, cold flow and Mooney value were determined for each sample.

Table IV below shows a compilation of the approaches.

Table IV

Composition, parts by weight cis-polybutadiene
Benzoyl peroxide,
Maleic anhydride.

100 100 0.10 0.1 0.1

Physical Properties

Gel, ο / «0

Inherent viscosity 1.76

Cold flow, mg / min 5.2

Mooney ( ² ), (ML-Φ at

100 ° C) 24.3

C) 0.41 millimoles per 100 grams of rubber. ( ² ) See footnote ( ² ) of Table I.

1.85 3.3

25.0

100 0.1 0.2

A number of approaches were made similar to Approaches 2 and 3 above, but were followed by the initial one Heat treatment 3 parts by weight of zinc oxide per 100 parts of rubber added. From these masses the following cold flow values were obtained:

Cold flow mg / min.

approaches

3.0

1.4

These values show that treatment with zinc oxide resulted in a further reduction in cold flow resulted.

Example 3

The cis-polybutadiene from Example 2 was treated with variable amounts of benzoyl peroxide, maleic anhydride and zinc oxide. After incorporation of the active ingredients on a two-roll calender, the polymers in a press were 10 minutes at 152 ⁰ C.

heated and the properties determined as in Example 2. The polymers were then using the recipe given in Example 1 mixed up. When mixing were the masses that a zinc compound added before the heat treatment

10

oxide, no additional zinc oxide was added. For those approaches where there is no zinc oxide before the heat treatment was added, 3 parts were used as indicated in the mixing recipe. the The amount of sulfenamide used was 1.0 part.

Table V

approach Before heating
added amounts Malein- _{7 AD}
anhydride | ^nu
phr Π; phrO) Properties after heating Own
viscosity gel
° / o Cold
flow
mg / min. Observations on the masses soot
incorporation Mooney
value
MS-1 ¹ W ² ) No. Benzoyl
peroxide
phrO 0.35 ML-4 ( ² ) 1.75 0 10.9 Knead hot excellent 28 1 0.35 17th 1.90 0 2.0 excellent Well 32 2 0.1 (·) 7.5 24 difficult 0.35 3 1.66 0 11.7 somewhat limp excellent 29 3 - 0.35 19th 2.06 0 1.4 excellent excellent - 4th 0.1 28 Well

Parts by weight per 100 parts of rubber. ( ² ) See footnote ( ² ) of Table I. ( ³ ) 0.41 millimoles per 100 grams of rubber.

These values show that maleic anhydride alone or together with zinc oxide has little effect had on cold flow (the cold flow of the original polymer was 13.5) when no benzoyl peroxide was added. As can be seen from Run 2, the cold flow was greatly reduced if only maleic anhydride and benzoyl peroxide were used. If, as in approach 4, all three active ingredients were used, then was the tendency of the polymer with the low Mooney degree to cold flow is substantially reduced and the polymer had good processing properties.

Example 4

The cis-polybutadiene of Example 2 was without Active ingredients, with zinc oxide alone and with benzoyl peroxide, maleic anhydride and zinc oxide together Subjected to heat treatment. The active ingredients were mixed up according to the recipe. So much for the masses already contained zinc oxide, none was added during mixing. The others got 3 parts Zinc oxide along with the other additives

with the polymer added for 10 minutes in a Banbury-4 °. A control batch was run with a mixer at a jacket temperature of 163 ^° C. using the cis-polybutadiene from example 1. One mixed. The masses were made according to the batches summarized in Example 1, Table VI below

Table VI

cis-PBd
control

cis-polybutadiene

Benzoyl peroxide, phr

Maleic anhydride, phr

Zinc oxide, phr

Cold flow, mg / min

Mooney ^(a), (ML-4 at 10O ⁰ C).

Mooney ( ² ) (MS-I ¹ J ₂ at 100 ^° C). Extrusion ( ³ )

cm / min

g / min

valuation

Appearance when cut off

*) Notes at the end of the table.

100

18 18

106.4 96

12-

smooth

Recipes, parts by weight

100

100 100 0.1 (4) 0.12 0.35 0.42 3 3

Properties in the raw state

8.6 18

18th

114.3

102.2

12-

smooth 3.4
21

1.6
26th

100

0.15 («)
0.53
3

0.7
36

Properties compounded
21 25 33

124.3
115
10

smooth

102
105
9-

smooth

82
89.5
8th-

a bit rough

100

2.9

47

rough

509 520/448

11

Table VI (continued)

12th

cis-PBd control

Properties of the vulcanizate (cured for 30 minutes at 152 ° C)

Sulfenamide

ν · 10 ⁴ , mol / cm ⁸ .... 300% modulus kg / cm ^a tensile strength kg / cm *.

Elongation, ° / ₀

Shore A hardness

Δ T, ⁰ C

elasticity

1.1 1.1 1.05 1.15 1.79 1.72 1.60 1.70 85.8 83.7 80.8 95.6 177.9 185.3 176.2 199.4 610 610 630 610 56 56 56 56 30th 28.8 30th 31.7 75 75 74 72

1.25
2.02
120.2
172.6
440
61

26.7
77

Aged for hours at 100 ° C

ν · 10 ⁴ , mol / cm ³

300% modulus, kg / cm ^a tensile strength, kg / cm ² .

Strain, %

AT, ⁰ C

Elasticity,%

2.71 132.2 140.6 320

23.9

81

2.77 138.5 148.3 320

23.9

79

2.64
146.9
153.3
310

22.2

78

2.77 3.0 158.9 158.9 169.4 300 270 22.2 21.7 82 82

1.0 2.17 99.8 190.9 530 62 28.8 73

3.08 159.3 178.3 340

26.1

C) Slightly reduced cold flow as a result of high shear conditions.

(·) See footnote (*) of Table I. For the other properties, see footnote of Table II.

C) The extrusion was carried out at 121 ° C by essentially the same procedure as in G a r ν e y et al, Ind. & Eng., Chem., 34, p. 1309 (1942). In the "Rating" column, 12 means an extrusion that is perfectly shaped

accepted, while lower numbers indicate a less perfect product. C) 0.41 millimoles per 100 grams of rubber.
(·) 0.50 millimoles per 100 grams of rubber.
(·) 0.62 millimoles per 100 grams of rubber.

The values of Table VI show that it is possible to add properties of Runs 3, 4 and 5 which to reduce the cold flow and still good that of the 47-Mooney-cis-polybutadiene similar Retain processing properties. At the same time 35 are and also show better processing properties The volcanic shafts have reduced cold flow.

Example 5

The cis-polybutadiene of Example 2 was made with benzoyl peroxide, maleic anhydride and various Metal oxides heat-treated. The active ingredients were kneaded on a calender and then kneaded for 10 minutes

Masses were mixed according to the recipe given in Example 1, only the amounts of metal oxides, des Sulfur and sulfenamide were, as Table VII shows has been changed. The one in this series of approaches

heated to 152 ° C. After the heat treatment of the 45 results obtained, Table VII also shows.

Table VII

cis-polybutadiene

Benzoyl peroxide

Maleic anhydride

Zinc oxide

Metallic lead (PbO)

Magnesia

Red lead (Pb ₃ O ₄ )

Gd, 7.

Inherent viscosity

Cold flow, m / min

Mooney (*) (ML-4 at 100 ° Q

') See footnote (*) of table «) 0.45 millimoles per 100 g of rubber.

Recipes, parts by weight

100
0.11
0.4

100
0.11
0.4

Properties in the raw state

0 0 0 0 1.95 1.98 1.83 1.97 1.0 0.9 1.1 0.8 30.2 31 28.4 32

100
0.11 0.4

Table VII (continued)

Properties of the mixture

Sulfur, phr

Sulfenamide, phr

Mooney (*) (Ms-I% at 100 ⁰ C)

Observations while kneading

( ¹ ) See footnote ( ² ) of Table I.

( ² ) 0.45 millimoles per 100 grams of rubber.

Example 6

The cis-polybutadiene from Example 2 was subjected to a heat treatment with benzoyl peroxide, maleic anhydride and magnesium oxide. For this purpose, the reactants were mixed for 10 minutes in a Banbury mixer dwarf at a jacket temperature of 163 ⁰ C and a speed of 45 rpm. After the heat treatment, the compositions were cobaltnitrite in a midget Banbury within 8 minutes at a jacket temperature of 121 ⁰ C and a speed of 45 rpm. For this purpose, a control approach was run using a

1.75 1.2

47

quite

bad

a little flabby 1.75
U
47

quite

bad

somewhat limp

2.0 1.3 44

bad a little limp

1.75

1.1

50

quite

bad

somewhat limp

cis-polybutadiene with higher Mooney degrees, which had the following properties:

Mooney (*) (ML-4 at 100 ⁰ C)

Intrinsic viscosity 2.48

Gel, "A,

Micro structure,%

ice 95.3

trans 1.8

Vinyl 2.9

C ¹ ) See footnote ( ² ) of Table I.

The results of these runs are shown in Table VIII below.

Table VIII

Recipes, parts by weight

cis-polybutadiene 45 ML-4

cis-polybutadiene 17 ML-4

Magnesia

Benzoyl peroxide

Maleic anhydride

Storage temperature (*), ° C

Mooney ( ² ), (ML-4 at 100 ⁰ C)

Cold flow, mg / min

Heat-treated matrix or polymer

Highly abrasion-resistant furnace soot

Magnesia

Stearic acid

Amine mixture ( ³ )

disprop. rosin

Aromatic oil

Storage temperature ( ¹ X ⁰ C

Total energy watt-hours

Mooney, ( ² ) (MS-I V ₂ at 100 ° C)

Extrusion at 121 ^° C

cm / min

g / min

valuation

C ¹ ) The temperature at which the polymer comes out of the rolling mill.

( ^a ) See footnote ( ² ) of Table I.
( ³ ) A physical mixture containing 65 percent by weight of a complex diarylaminoketone reaction product and 35 ge

100 100
3

0.11 (*)
0.4

0.13 (0.473

After the heat treatment

154 38.8 2.9

100 50 3 1 1 5 5

138 549 40.5

79.7 86.5 160
21.1
4.6

160 24.0 2.5

0.15 C 0.545

154 26.0 1.8

Mixing recipes, parts by weight

103 103.51 50 50

1 1

1 1

5 5

5 5

Machining values

138
465

23.5

120.5
112.5
■ 12—

143 495 25.0

116 112.0 11-

103.695 50

1 1

146 504 26.5

107 106.5 10

contains weight percent of Ν, Ν'-diphenyl-p-phenylenediamine.

( ⁴ ) 0.45 millimoles per 100 grams of rubber.

( ⁵ ) 0.54 millimoles per 100 grams of rubber.

( ⁶ ) 0.62 millimoles per 100 grams of rubber.

15th

These values show that the result of treatment with magnesium oxide, benzoyl peroxide and maleic anhydride results in a reduction in cold flow in the low Mooney grade polymer.

The treated polymer samples had much lower Mooney values after mixing than the control, and the machining properties were better than the control.

Example 7

The polymer described in Example 2 was the active ingredients on a polymer

mixed only once with the various peroxides and two-roll calenders, and then

once with the same peroxides, combined with the samples in a press for 10 minutes at 152 ⁰ C.

Maleic anhydride. Heated io during this treatment.

The results of these runs are shown in Table IX below.

Table IX

Peroxide phr mmol Painting
anhydride Own
viscosity gel ML-4 at
100 ⁰ C Cold flow 0.14 0.58 phr ° / o mg / min. 0.09 0.37 _ 2.24 2 32 3.6 0.14 0.96 0.32 2.18 0 32 2.9 0.09 0.62 - 2.19 0 33 2.7 0.14 0.52 0.32 2.32 0 38 1.0 0.09 0.33 - 2.78 0 74 0 0.14 0.49 0.32 2.94 4th 78 0 0.09 0.31 - 2.18 0 33 2.4 0.14 0.92 0.32 2.34 0 43 1.1 0.09 0.59 - 2.20 0 33 2.6 0.14 0.45 0.32 2.38 traces 42 1.0 0.09 0.29 - 2.19 traces 30th 7.0 0.14 0.72 0.32 2.21 0 31 4.6 0.09 0.46 - 2.18 0 32 2.7 0.14 1.56 0.32 2.29 0 38 1.4 0.09 1.00 - 2.41 0 31 4.5 0.32 2.20 0 33 2.6

Dibenzoyl peroxide

Dibenzoyl peroxide

Di-tert-butyl peroxide

Di-tert-butyl peroxide

Dicumyl peroxide

Dicumyl peroxide

Peroxide mixture (*)

Peroxide mixture (*)

Cumene hydroperoxide

Cumene hydroperoxide

p-chlorobenzoyl peroxide

p-chlorobenzoyl peroxide

Diisopropylbenzene hydroperoxide Diisopropylbenzene hydroperoxide

tert-butyl hydroperoxide

tert-butyl hydroperoxide

0) A 50% active material containing equal parts of 2,5-bis- (tert-butylperoxy) -2,5-dimethylhexane in an inert free-flowing mineral carrier.

The untreated polymer used in these runs had a cold flow of 13.5 mg / min. on. The data in Table IX show that there was a reduction in cold flow in all cases. the However, effect was better with the combination of peroxides and maleic anhydride than with the Peroxides alone.

Example 8

45

Two approaches have been carried out, with the polymerization of butadiene in the presence of one Aluminum triisobutyl titanium tetrachloride iodine catalyst system using toluene as the diluent a cis-polybutadiene was produced.

These polymers have Mooney values (ML-4 at 100 ⁰ C) was added by 45 and 19. Before the diluent was removed by steam, various amounts of benzoyl peroxide to samples of the two polymer solutions. The sample containing the polymer with the higher Mooney value was treated with benzoyl peroxide and maleic anhydride. After the toluene had been removed by steam, the polymers were ^{dried in vacuo at a temperature of approximately 143 °} C. in the extruder. The polymers were stabilized with 0.25 phr of 2,2'-methylene-bis- (4-methyl-6-tert-butylphenol). The results obtained with the untreated as well as with the treated polymers are shown in Table X.

Table X

Approach no.

cis-polybutadiene starting ML-4

100 ⁰ C

Benzoyl peroxide,

phr

mmol

Maleic anhydride, phr

End-ML-4 at 100 ⁰ C

Cold flow, mg / min.

Inherent viscosity

Gel,"·/,

45

45 2.9 2.52 0

45

0.05 0.21 0.10 48 1.2 2.67 0 45

0.10
0.41

55
0.2
2.70
0

19th

19th
12.1

1.91

19th

0.14
0.58

33
0.8
2.35
0

19th

0.18
0.74

49
0

2.53
0

17th

The values in Table X show that by treating the polymers with benzoyl peroxide or a mixture of the peroxide and maleic anhydride the cold flow was reduced.

The polymer from run 5, which after treatment had a Mooney value of 33, as well as a Untreated cis-polybutadiene with a Mooney value of 43 were mixed, 30 minutes at 152 ° C hardened and the physical properties determined. Table XI shows the values obtained.

Table XI

Table XI (continued)

ML-4 at 10O ⁰ C ... cold flow, mg / min.

Polymer

Highly abrasion-resistant furnace soot

Zinc oxide

Stearic acid

Amine mixture (*)

Disprop. Rosin...

Aromatic oil

sulfur

Sulfenamide ( ² )

MS IV ₂ at 100 ^° C

Extrusion at 121 ^° C

cm / min

g / min

Mouthpiece evaluation according to G a r ν e y

*) Notes at the end of the table.

approach

Treated polymer

Untreated polymer

Unmixed polymers

33 0.8

43 3.6

Mixing recipe, parts by weight

100 50 3 1 1 5 5

1.75 1.1

100 50

1.75

1.1

Machining values 35.5

30 92.5

12th

38.2 105

8+

v · 10 ⁴ , mol / cm ³

300% module, kg / cm ⁸ ....

Tensile strength kg / cm ²

Strain %

AT, ⁰ C

elasticity

Shore A hardness

Approach 5

Treated
Polymer

Untreated
Polymer

Physical
Properties of the
hardened masses

1.89
83.0

170.8

475
27.6
71.7
59

1.90

78.7
184.2
520

27.4

72.7

60

0) A physical mixture containing 65 ⁰ I _{0 of} a complex diarylamine ketone reaction product and 35% N, N'-diphenylp-phenylenediamine.
( ² ) N-oxydiethylen-2-benzothiazylsulfenamide.

The data in Table XI show that the low Mooney grade polymer after treatment with a organic peroxide to reduce cold flow

«5 delivered a rubber that after extrusion a smoother appearance (mouthpiece rating according to G a r ν e y) than the untreated polymer had a higher Mooney grade. In addition, the treated polymer had a low Mooney grade physical properties not significantly different from those of the higher Mooney grade polymer differentiated.

Claims (1)

Claim: Process for preventing the cold flow of unvulcanized cis-1,4-polybutadiene, characterized in that per 100 g of cis-1,4-polybutadiene with 0.075 to 1.75 mmol of an organic peroxide or organic hydroperoxide, optionally in the presence of 0.015 to 1.2 g of maleic acid or maleic anhydride and heated from 1 to 10 g zinc oxide, magnesium oxide or lead oxide at 120 to 180 ⁰ C.