CH628069A5 - Process for crosslinking halogenated polymers - Google Patents

Description

The invention is illustrated by the following nonlimiting examples. Example 1:

This example illustrates the preparation of a concentrate of 2,5-dimercapto thiadiazole-1,3,4 in stearic acid.

The concentrate is prepared by dry mixing the ingredients indicated above, heating the concentrated mixture to the melting point of stearic acid, extruding the molten concentrate and dividing the extruded element into rods or pellets.

Ingredients

Parts dimercapto-2,5 thiadiazole-1,3,4 stearic acid clay type kaolin plasticizer polymer form

66.6

16.7 7.5 9.2

soft white meatballs

We can suggest the use of this concentrate for the crosslinking of an epichlorohydrin copolymer.

5

10

15

20

25

30

35

40

45

50

55

60

65

628069

4

In the following examples, a Banbury ingredients blender is used in the blender in the order shown in each

Farrel, model B, to form the compositions. We introduce the examples.

Example 2:

Ingredients

Copolymer parts of epichlorohydrin and ethylene oxide (26% chlorine)

100

DS-207 (non-commercial mixture of dibasic lead salts of C16- fatty acids

"l8>

marketed by National Lead Co.) (processing aid)

1

carbon black (reinforcing filler)

40

nickel dimethyldithiocarbamate (antioxidant)

1

magnesium oxide

4

dimercapto-2,5 thiadiazole-1,3,4

1.5

Samples of the mixture are crosslinked by heating for 30 min at a temperature of 160 ° C. in a compression mold. The physical properties of the crosslinked product are shown below:

After 70 h

At the origin of aging in the oven

in air at 150 ° C

tensile strength (bars)

123.3

123.0

elongation (%)

58.2

13.4

100% module (bars)

12,420

12,450

Shore A hardness

77

79

permanent compression deformation (according to ASTM D-395,

method B)

-

46

Example 3:

Ingredients

Copolymer parts of epichlorohydrin and ethylene oxide (26% chlorine)

100

Hydrex 440 (trade name of hydrogenated fatty acids and glycerides marketed by Wallace and

Tiernan Inc., Harchem Div.) (Processing aid)

1

carbon black

40

nickel dibutyldithiocarbamate (antioxidant)

1

calcium hydroxide

3.5

malic acid (anti-crawler)

0.27

N-acetylanthranilic acid (anti-screen)

2.5

dimercapto-2,5 thiadiazole-1,3,4

1.5

The composition is crosslinked by heating for 30 min at 160 ° C. in a compression mold. The crosslinked product has the following physical properties:

After 70 h

At the origin of aging in the oven

in air at 150 ° C

tensile strength (bars)

119.5

119.5

elongation (%)

290

185

100% module (bars)

63.7

72.3

Shore A hardness

77

77

permanent compression deformation (ASTM D-395, method B)

-

58.5

Mooney roasting (at 121 ° C) (ASTM D-1646-68)

minimum viscosity

30

time (min) for a viscosity increase of 3 points

7.7

time (min) for a viscosity increase of 5 points

8.7

time (min) for a 10 point increase in viscosity

10.3

5

628069

Examples 4 and 5:

Ingredients

Parts

Example 4

Example 5

epichlorohydrin homopolymer (38% chlorine)

100

100

DS-207 (trade name of a mixture of dibasic lead salts of fatty acids

in Cie-Cj 8, marketed by National Lead Co.) (processing aid)

1

1

carbon black (reinforcing filler)

50

50

nickel dimethyldithiocarbamate (antioxidant)

1

1

calcium oxide

3

3

tetramethylammonium bromide

2.0

tetrabutylammonium bromide

-

0.1

dimercapto-2,5 thiadiazole-1,3,4

1.0

1.0

The above compositions are crosslinked by heating for 30 min at 160 ° C in a compression mold. Crosslinked products have the following physical properties:

Originally

After 70 hours of aging in an oven in air at 150 ° C

Originally

After 70 hours of aging in an oven in air at 150 ° C

tensile strength (bars)

127.5

146.4

106.1

130.9

elongation (%)

290

200

300

200

100% module (bars)

62.0

95.4

48.2

81.0

Shore A hardness

77

83

72

81

permanent compression deformation (ASTM D-395, method B)

70

58

Mooney roasting (at 121 ° C) (ASTM D-1646-68) minimum viscosity

38

34

time (min) for a viscosity increase of 3 points

5.3

4.6

time (min) for a viscosity increase of 5 points

6.1

5.2

time (min) for a 10 point increase in viscosity

7.2

6.2

Examples 6 and 7:

Ingredients

Parts

Example 6

Example 7

chlorinated polyethylene (36% by weight of chlorine)

100

-

chlorinated polyethylene (48% by weight of chlorine)

-

100

carbon black (reinforcing filler)

85

85

magnesium oxide

4

4

dioctyl adipate (plasticizer and peptizer)

15

15

1,2-dihydro-2,2,4-trimethyl quinoline polymerized (antioxidant)

0.1

0.1

di-o-tolylguanidine

1

1

dimercapto-2,5 thiadiazole-1,3,4

1.25

1.25

The above compositions are crosslinked by heating for 30 min at 160 ° C. in a steam autoclave. Crosslinked products have the following physical properties:

628069

6

Example 6

Example 7

tensile strength (bars)

138.5

170.5

elongation (%)

200

170

100% module (bars)

112.7

159.5

Shore A hardness

86

91

permanent compression deformation (ASTM D-395, method B)

66

82

Mooney roasting (at 121 ° C) (ASTM D-1646-68)

minimum viscosity

69

56

time (min) for a viscosity increase of 3 points

14.0

12.3

time (min) for a viscosity increase of 5 points

20.0

15.2

time (min) for a 10 point increase in viscosity

25.0

21.0

Example 8:

Ingredients

Homopolymer parts of epichlorohydrin

50

Hycar 1053 (copolymer of acrylonitrile and

low molecular weight butadiene,

made by B. F. Goodrich)

50

DS-207 (trade name of a

mixture of dibasic lead salts

of Ci6-C18 fatty acids marketed by

National Lead Co.) (implementation aid

artwork)

0.5

zinc stearate (processing aid)

0.5

carbon black (reinforcing filler)

45

magnesium oxide

1.5

zinc oxide*

5

octylated diphenylamine (antioxidant)

1

benzothiazyl disulfide *

0.5

sulfur*

1.25

dimercapto-2,5 thiadiazole-1,3,4

0.625

tetramethylammonium bromide

1.0

* Hycar 1053 curing agents.

Examples 10 and 11:

To crosslink the composition, it is heated for 30 min at a temperature of 160 ° C. in a compression mold. The crosslinked product has the following physical properties:

tensile strength (bars) 217.0

elongation (%) 400 module at 100% (bars) 40.3 Shore A hardness 67

Example 9:

Ingredients

Copolymer parts of epichlorohydrin and oxide

ethylene (26% chlorine)

100

stearic acid (processing aid)

1

dimercapto-2,5 thiadiazole-1,3,4

1.5

tributylamine

5

To crosslink the above composition, it is heated at 160 ° C for 30 min in an oscillating disc rheometer (ASTM D 2705-68T). The properties measured are as follows:

minimum torque (J) 0.68

torque after 30 min (D) 3.95

torque after 60 min (D) 4.52

Ingredients

Parts

Example 10

Example 11

chlorinated polyethylene (36% by weight of chlorine)

100

100

carbon black (reinforcing filler)

85

85

dioctyl phthalate (plasticizer and peptizer)

20

20

magnesium oxide

5

5

dimercapto-2,5 thiadiazole-1,3,4

1.5

1.5

diphenylguanidine

1.5

-

butyraldehyde and aniline reaction product

-

1.5

To crosslink the above compositions, they are heated at 160 ° C for 30 min in a compression mold. The physical properties of the crosslinked products are as follows:

Example 10

Example 11

tensile strength

(bars)

142.6

146.1

elongation (%)

250

240

100% module (bars)

75.8

86.1

Shore A hardness

80

81

7 628069

Example 12: Example 13:

io

Ingredients

Poly (vinyl chloride) parts

100

Santocizer 160 (phthalic ester plasticizer

marketed by Monsanto)

40

Ba-Cd 1203 (stabilizer consisting of

barium and cadmium soap co-precipitated

marketed by Ferro Corp.)

1.2

calcium carbonate

20

dimercapto-2,5 thiadiazole-1,3,4

1.2

butyraldehyde reaction product and

aniline

1

Ingredients

Copolymer parts of vinylidene fluoride and

hexafluoropropylene

100

calcium oxide

5

di-o-tolylguanidine

3

dimercapto-2,5 thiadiazole-1,3,4

2

The above composition is heated at 135 ° C for 30 min in an oscillating disc rheometer (according to the ASTM D 2705-68T method). Satisfactory crosslinking is obtained without significant change in color.

The above composition is heated at 160 ° C for 30 min in an oscillating disc rheometer (ASTM D 2705-68T). Satisfactory crosslinking is obtained.

Examples 14 and 15:

These examples illustrate the preaction of dimercapto-2,5 thiadiazole-1,3,4 with an organic basic material. The reaction product is then used to crosslink a saturated halogenated polymer.

Heated to 45 ° C for 20 min a mixture of 15 g (0.1 mol) under a pressure of about 18 mmHg. Analysis of the product indicates that dimercapto-2,5 thiadiazole-1,3,4 and 37 g (0.2 mol) of tributylamine are a bis-salt.

in 200 ml of tetrahydrofuran. A yellow precipitate crystallizes in. The reaction product obtained above is used to crosslink the solution, it is filtered and washed with methylene chloride. A copolymer of epichlorohydrin and ethylene oxide is used to dry the product overnight in a vacuum oven at 50 ° C, following composition:

Ingredients

Parts

Example 14

Example 15

copolymer of epichlorohydrin and ethylene oxide (26% chlorine)

stearic acid (processing aid)

barium carbonate product of the reaction of 2,5-dimercapto-1,3,4-thiadiazole and tributylamine

100 1

5.2

100 1

7.5 5.2

The above compositions are crosslinked by heating at 160 ° C for 30 min in an oscillating disc rheometer (ASTM D 2705-68T). The properties measured are as follows:

Example 14

Example 15

minimum torque (J)

0.79

1.13

couple after 30 min (J)

5.42

9.04

couple after 60 min (J)

4.52

9.15

Claims (3)

628069 1. Process for crosslinking a saturated halogenated polymer, characterized in that it consists in heating this polymer in the presence of a basic material and of 2,5-dimercapto-1,3,4-thiadiazole or in the presence of a salt which results from the reaction of a basic material with dimercapto-2,5-thiadiazole-1,3,4. 2. Method according to claim 1, characterized in that the basic material is a basic metal oxide. 3. Process according to claim 2, characterized in that the basic metal oxide is magnesium oxide. 4. Method according to claim 2, characterized in that the basic metal oxide is calcium oxide. 5. Method according to claim 1, characterized in that the basic material is a basic metal salt. 6. Method according to claim 5, characterized in that the basic metal salt is a basic metal carbonate. 7. Method according to claim 6, characterized in that the basic metal carbonate is barium carbonate. 8. Method according to claim 6, characterized in that the basic metal carbonate is calcium carbonate. 9. Method according to claim 6, characterized in that the basic metal carbonate is magnesium carbonate. 10. Method according to claim 6, characterized in that the basic metal carbonate is strontium carbonate. 11. Method according to claim 1, characterized in that the basic material is a basic metal hydroxide. 12. Method according to claim 11, characterized in that the basic metal hydroxide is calcium hydroxide. 13. Method according to claim 1, characterized in that the saturated halogenated polymer is a homopolymer of epichlorohydrin. 14. Method according to claim 1, characterized in that the saturated halogenated polymer is a copolymer of epichlorohydrin and ethylene oxide. 15. Method according to claim 1, characterized in that the saturated halogenated polymer is a chlorinated polyethylene. 16. Method according to claim 1, characterized in that the saturated halogenated polymer is a poly (vinyl chloride). 17. Method according to claim 1, characterized in that the basic material is a combination of an inorganic basic material and an organic basic material. 18. The method of claim 17, characterized in that the organic basic material is di-o-tolylguanidine. 19. The method of claim 17, characterized in that the organic basic material is the product of the reaction of butyral-dehyde and aniline. 20. The method of claim 17, characterized in that the organic basic material is diphenylguanidine. 21. Method according to claim 1, characterized in that the basic material is an organic basic material. 22. The method of claim 21, characterized in that the organic basic material is chosen from primary, secondary and tertiary amines, amine salts and quarternary ammonium compounds. 23. The method of claim 21, characterized in that the organic basic material is dicyclohexylamine. 24. The method of claim 4, characterized in that at least one adds an organic carboxylic acid to the polymer before heating. 25. The method of claim 12, characterized in that at least one organic carboxylic acid is added to the polymer before heating. 26. Concentrate for the implementation of the method according to claim 1, characterized in that it consists of a binder containing at least 15% by weight of 2,5-dimercapto-1,3,4-thiadiazole. Dimercapto-2,5 thiadiazole-1,3,4 is a known compound and GB patent No. 974915 reported it as a curing agent for certain halogenated unsaturated polymers (for example chlorobutyl rubber or polychloroprene elastomers) . However, GB Patent No. 974915 does not suggest crosslinking of saturated halogenated polymers. The licensee has discovered that saturated halogenated polymers can be crosslinked hot to obtain stable vulcanizates with good aging behavior, good resistance to permanent compression deformation and insoluble in organic solvents when used as an agent. crosslinking agent, either 2,5-dimercapto-1,3,4-thiadiazole in the presence of a basic material, or a salt resulting from the reaction of this thiol with a basic material. In the invention, the term “basic materials” is intended to mean bases and materials which become basic when they are heated to crosslinking temperature. The starting saturated halogenated polymers may contain at least about 2% and preferably about 5% by weight of halogen. In general, saturated halogenated polymers are homopolymers of epichlorohydrin, copolymers of epichlorohydrin and ethylene oxide or propylene oxide, high density chlorinated polyethylene, chlorosulfonated polyethylene, poly (vinyl chloride) , poly (vinyl fluoride), poly (chloroalkyl acrylates), poly (vinylidene chloride) and copolymers of vinylidene fluoride and hexafluoropropylene. In addition, the process of the invention can be used to crosslink mixtures of saturated halogenated polymers, or of saturated halogenated polymers and other polymers. The only condition is that the mixture contains sufficient halogenated saturated polymers for crosslinking to take place. As previously indicated, it is possible to use, as hardening activators, various bases or materials which become basic when they are heated to the crosslinking temperature, that is to say basic materials. Typical mineral basic materials are oxides, hydroxides and weak acid salts of basic metals, for example lead oxides, zinc oxide, magnesium oxide, calcium oxide, calcium hydroxide , barium oxide, zinc carbonate, lead acetate, barium carbonate, strontium carbonate, sodium phenolate and sodium acetate. The preferred basic mineral materials are calcium oxide, calcium hydroxide, magnesium oxide and barium carbonate. Organic basic materials can be used instead of or in combination with mineral basic materials. As typical examples of these basic organic materials, primary, secondary and tertiary amines, amine salts and quaternary ammonium compounds can be cited. The preferred organic basic materials are tetramethylammonium bromide, tetrabutylammonium bromide, tetraethylammonium benzoate, tetraethylammonium acetate, tetraethylammonium nitrate, benzyltrimethylam-monium bromide, 2-famino-2 thiazoline, diazabicyclooctane, hexamethylenetetramine, hexamethylenediamine carbamate, N, N'-dicinn-amylidenehexanediamine-1,6, dicyclohexylamine, di-o-tolylguanidine, diphenylguanidine and butyraldehyde reaction products aniline. It is also possible to use, as crosslinking agents, separately or in combination with an additional basic material, the thiolates formed by reacting 2,5-dimercapto-1,3,4-thiadiazole with a basic mineral oxide or hydroxide. The products of the reaction of organic amines and 2,5-dimercapto-thiadiazole-1,3,4 can also be used as crosslinking agents, separately or in combination with a basic mineral material. In the case of many saturated halogenated polymers in which 2,5-dimercapto-1,3-thiadiazole or its aforementioned reaction products formed with basic materials are relatively insoluble, such as poly (vinyl chloride), poly (vinyl fluoride), poly (chloroalkyl acrylates), chlorinated polyethylene, homopolymers of epichlorohydrin, poly (vinylidene fluoride), 5 10 15 20 25 30 35 40 45 50 55 60 65 2 3 628069 copolymers of vinylidene fluoride and hexafluoropropylene, chlorosulfonated polyethylene and poly (vinylidene chloride), it may be desirable to use a combination of mineral and organic basic materials. The organic basic materials which are particularly preferred to be used in combination with the mineral basic materials are dicyclohexylamine, di-o-tolylguanidine, diphenylguanidine or their salts, and the reaction product of butyraldehyde and aniline. In some cases it may be undesirable to use zinc oxide or zinc salts as basic materials, for example with chlorosulfonated polyethylene, chlorinated polyethylene, poly (vinyl chloride) or poly (chloride vinylidene), since zinc chloride formed in situ during the vulcanization process can cause undesirable degradation by breaking the polymer chains. Various amounts of the crosslinking agent and basic material can be added, and the optimal amount depends on the degree of crosslinking desired. Generally, the amounts added (relative to the weight of the polymer) are included in the following ranges: 2,5-dimercapto-1,3,4-thiadiazole, from approximately 0.1 to approximately 20%, preferably from approximately 0 , 25 to about 5.0%; basic material (organic or inorganic), from about 0.25 to about 50%, better still, from about 0.5 to about 50% and, more particularly, from about 1.0 to about 20%; and in the case where an organic basic material is used in combination with the mineral basic material, the amount of organic basic material can be between approximately 0.01 and approximately 5% and, better still, between approximately 0.05 and approximately 5% , especially between about 0.1 and about 2%. In addition to the crosslinking agent and the basic material, other ingredients can also be incorporated. The types of additives commonly used in the vulcanization of rubber, such as, for example, diluents, fillers, pigments, plasticizers, peptizers, etc., can be used. The presence of a filler and in particular of carbon black is useful and it leads to very advantageous results in the compositions of hydrocarbon rubber. There are, however, many cases where such a filler is unnecessary or undesirable and where excellent results are obtained when only the crosslinking agent and the basic materials are added. Also, most of the saturated halogenated polymers contain a small amount (about 0.1 to about 2% by weight) of an antioxidant that was added to them during preparation. It may be desirable in some cases to add a small amount of antioxidant before or during crosslinking of the polymer. Examples of preferred antioxidants that may be mentioned include phenyl ß-naphthyl amine, di-ß-naphthyl p-phenylenediamine, sym-di-ß-naphthyl p-phenylenediamine, N-isooctyl p-aminophenol, the product of reaction of diphenylamine and acetone, polymerized trimethyldihydroquinoline, thio-4,4 'bis (tert-butyl-6 m-cresol), the reaction product of crotonaldehyde and 3-methyl-tert-butyl-6 phenol, nickel dibutyldithiocarbamate, the zinc salt of 2-mercapto-benzimidazole and nickel dimethyldithiocarbamate. In particular, when epichlorohydrin polymers are used, it may be advantageous to add at least one carboxylic acid to the crosslinkable composition so that it behaves like an anti-grist during the composition stage when it is used as material basic calcium oxide or calcium hydroxide. Malic acid and N-acetylanthranilic acid are particularly useful. Any crosslinking agent, basic material and optional additives can be incorporated into or mixed with the polymer. One can for example, to obtain a uniform mixture with a polymer, use a simple rubber mixer or a Banbury mixer. The crosslinking agent and the basic material are thus distributed uniformly throughout the polymer and uniform crosslinking is obtained when the mixture is heated. It is generally preferred to knead at temperatures in the range of about 20 to about 95 ° C. However, the mixtures generally resist roasting below 120 ° C when a significant amount of organic basic material has not been incorporated into them. Other methods of mixing the crosslinking agent and. of the polymer are obvious to those skilled in the art. The conditions under which crosslinking is carried out can vary over a wide range. Crosslinking can be done in minutes at elevated temperatures, or in days at temperatures slightly above room temperature. In general, the crosslinking temperature is in the range of from about 30 to about 280 ° C, more preferably from about 135 to about 235 ° C and most particularly from about 150 to about 205 ° C. The time varies inversely with temperature and is in the range of from about 30 s to 70 h and preferably from about 30 s to about 120 min. Although crosslinking can be carried out in air under normal atmospheric pressure, it is generally carried out in a metal mold under a pressure of at least about 3.4 bars or in an autoclave under the vapor pressure corresponding to the desired temperature. To facilitate the incorporation of 2,5-dimercapto-1,3,4-thiadiazole into the crosslinkable polymer and to avoid using powders in the composition stage, it may be desirable to prepare 2,5-dimercapto-thiadiazole-1, 3,4 in the form of a concentrate in a binder or a support which can be added, with the basic materials in small amounts to the polymer composition, without harming the properties of the crosslinked composition. In particular, advantageous binders or supports are polymers which may or may not be crosslinkable by the crosslinking agent. Suitable materials, in addition to crosslinkable polymers, are, for example, ethylene propylene rubber, ethylene propylene terpolymers, butadiene and styrene rubber, natural rubber, low density polyethylene, polypropylene amorphous and a polyisobutylene. The concentrations of dimercapto-2,5 thiadiazole-1,3,4 in the binders can vary between approximately 15 and approximately 90%, preferably between approximately 30 and approximately 75%. Other materials which can be advantageously incorporated into the concentrates are anti-screeners, antioxidants and non-basic fillers. It is generally undesirable to incorporate the basic material into the concentrate. These polymer concentrates are normally stored and used in the form of sheets, pellets or extruded stems. Other binders or carriers that can be used to prepare these easy-to-handle concentrates are waxes, resins, or other low-melting solids. Typical useful materials are paraffin wax, stearic acid, microcrystalline wax, rosin, rosin esters and hydrocarbon resins. The crosslinked products of the invention can be used to manufacture flexible or other tubes, useful for the transport of hydrocarbon fuels.