Novel rubber crosslinking agent and method for preparing the same

Abstract

The present invention relates to novel sulfur-olefin adducts, which are useful as rubber crosslinking agents with superior rubber mixing performance and provide vulcanized rubber composites with improved dynamic properties. The present invention further relates to a method for preparing novel sulfur-olefin adducts by reacting sulfur with an olefin compound in the presence of a catalyst.

Claims

1. A sulfur-olefin adduct, The adduct contains sulfur and high molecular weight sulfur in a ratio of 1.5:1 to 9:

1. The aforementioned sulfur-olefin adduct is characterized by being completely soluble in carbon disulfide, The sulfur adduct is characterized in that its differential scanning calorimetry (DSC) melting onset temperature is between approximately 90°C and approximately 100°C, and its final melting temperature is less than 110°C.

2. A sulfur-olefin adduct according to claim 1, The aforementioned polymeric sulfur is obtained by reacting sulfur with an olefin(s), The sulfur and olefin(s) in the reaction are in a weight ratio of 5:1 to 9.5:0.5, resulting in a sulfur-olefin adduct.

3. A sulfur-olefin adduct according to claim 1, The sulfur-olefin adduct is a sulfur-olefin adduct in which the toluene-soluble component is in the range of 25 to 99%, depending on the process parameters and the molar ratio of the reactants.

4. A sulfur-olefin adduct according to claim 1, The olefin is a sulfur-olefin adduct selected from isobutylene, isopentene, diisobutylene, triisobutylene; cycloalkenes such as cyclopentene and cyclohexene; unsaturated terpenes such as dipentene, pinene, camphene, and myrcene; aralkenes such as styrene, divinylbenzene, dihydronaphthalene, indene, and α-methylstyrene; polyolefins such as butadiene, isoprene, chloroprene, cyclopentadiene, dicyclopentadiene, cyclohexadiene, vinylcyclohexene, 1,7-octadiene, and cyclooctadiene, or mixtures thereof.

5. A sulfur-olefin adduct according to claim 1, The olefin compounds are sulfur-olefin adducts, which are aromatic olefins selected from styrene and α-methylstyrene, and aliphatic olefins selected from cyclopentadiene, dipentene, and dicyclopentadiene, or mixtures thereof.

6. A sulfur-olefin adduct according to claim 5, A sulfur-olefin adduct in which the weight ratio of the aromatic olefin to the aliphatic olefin is in the range of 1:1 to 10:1, preferably 1:1 to 4:

1.

7. A sulfur-olefin adduct according to claim 5, A sulfur-olefin adduct in which the aliphatic olefin is dicyclopentadiene and the aromatic olefin is styrene.

8. A catalytically controlled suspension polymerization method for preparing a sulfur-olefin adduct, comprising reacting sulfur with an aliphatic olefin and / or aromatic olefin, or a mixture of olefins, in a stirred reactor system in the presence of water, a base, a dispersant, and a catalyst, wherein the weight ratio of sulfur to olefin(es) at the start of the reaction is 5:1 to 9.5:0.5, and the weight ratio of water to the mixture of sulfur and olefin(es) is 1.5:1 to 10:

1.

9. A catalytically controlled suspension polymerization method for preparing the sulfur-olefin adduct described in claim 8, A method wherein the weight ratio of aromatic olefin to aliphatic olefin is in the range of 1:1 to 10:1, preferably 1:1 to 4:

1.

10. A catalytically controlled suspension polymerization method for preparing a sulfur-olefin adduct according to claim 8, comprising the following steps: a. Adding sulfur together with an olefin or a mixture of olefins in a stirred reactor system in the presence of water, a base, a dispersant, and a catalyst; b. Heat the reaction mixture at 120°C to 200°C for at least 2 hours while stirring; c. Cooling the sulfur-olefin adduct and isolating it in powder / granular form; d. Optionally, wash the powder / granular product with a suitable solvent to remove impurities; e. Optionally, dry the product; f. Optionally, form pastilles by pastilation or granules by granulation using appropriate equipment.

11. The method according to claim 8, The method wherein the base is selected from the group consisting of inorganic bases and organic bases, including alkali metal carbonates, alkaline earth metal carbonates, alkali metal hydroxides, tetraalkylammonium hydroxides, tertiary amines, primary amines, and secondary amines.

12. The method according to claim 11, The method wherein the base is selected from the group consisting of calcium carbonate, sodium carbonate, sodium hydroxide, triethylamine, and / or mixtures thereof.

13. The method according to claim 8, The method wherein the dispersant is selected from the group consisting of fatty alcohol ethoxylates, carboxymethylcellulose, polysorbates, anionic tristyrylphenol phosphates, or mixtures thereof.

14. The method according to claim 8, The catalyst is selected from the group consisting of metal salts of dialkyldithiocarbamates, thiuram disulfide, or mixtures thereof.

15. The method according to claim 14, A method wherein the amount of catalyst or a mixture of catalysts is 500 ppm to 5000 ppm relative to sulfur.

16. The method according to claim 8, A method comprising heating the aqueous suspension at a temperature of about 125°C to about 180°C for about 1 to 24 hours, more preferably 1 to 8 hours, and most preferably 5 to 6 hours for a reaction time.

17. The method according to claim 16, A method comprising heating the aqueous suspension at a temperature of approximately 150°C to 170°C for a reaction time of 5 to 6 hours.

18. The method according to claim 8, A method in which the mother liquor obtained after solid-liquid separation is reused in the main reaction between sulfur and olefin after undergoing an appropriate purification process.

19. A catalytically controlled suspension polymerization method for preparing powdered / granular sulfur-olefin adducts as crosslinking agents for rubber, comprising the following steps: (a) Reacting sulfur, olefin or mixture of olefins, water, base, dispersant and catalyst in a suitable stirred reactor system under conditions that, at the end of the reaction, high molecular weight sulfur and a mixture of sulfur are produced in powder / granular form and can be easily isolated from the reactor, wherein the weight ratio of sulfur to olefin or mixture of olefins at the start of the reaction is 5:1 to 9:1, and the weight ratio of water to sulfur and olefin or mixture of olefins is 2:1 to 10:1; (b) Heat the reaction mixture at 150°C to 180°C for 4 to 6 hours while stirring to form the powder / granular crosslinking agent; (c) Cooling the powdered / granular sulfur-olefin adduct and isolating it by filtration; (d) optionally wash the powder / granular product with water to remove impurities; (e) Dry the product; (f) Forming pastilles by pastillation or granules by granulation using appropriate equipment; (g) The obtained product is used in the rubber compounding of various rubber products.

20. A sulfur-olefin adduct according to claim 1, A sulfur-olefin adduct used for rubber compounding, either as is or on a support such as carbon black, silica, or a mixture thereof.

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