ELASTOMERIC TERPOLYMERS WITH A HIGH SULFUR CONTENT AND PROCESS FOR THEIR PREPARATION

Abstract

Elastomeric terpolymer with a high sulfur content comprising:sulfur in a quantity higher than or equal to 40% by weight, preferably ranging from 55% by weight to 90% by weight, with respect to the total weight of said elastomeric terpolymer;a first monomer selected from aromatic vinyl compounds, preferably from styrene, divinylbenzene, vinyl toluene, tert-butylstyrene, p-methylstyrene, -methylstyrene, -methylstyrene, vinylnaphthalene;a second monomer selected from:aromatic vinyl compounds, preferably from styrene, divinylbenzene, vinyl toluene, tert-butylstyrene, p-methylstyrene, -methylstyrene, -methylstyrene, vinyl-naphthalene;monomers having general formula (I): CH.sub.2CH(CH.sub.2).sub.y(X).sub.n(X).sub.m(CH.sub.2).sub.xCHCH.sub.2, wherein:X represents a sulfur atom, a selenium atom, a tellurium atom, preferably a sulfur atom, a selenium atom;y and x, equal to or different from one another, are a whole number ranging from 0 to 4;n and m, equal to or different from one another, are a whole number ranging from 0 to 3, at least one of n and m being equal to 1; said first monomer and said second monomer being present in a quantity lower than or equal to 60% by weight, preferably ranging from 10% by weight to 45% by weight, with respect to the total weight of said elastomeric terpolymer; said first monomer and said second monomer being different from one another. Said elastomeric terpolymer with a high sulfur content may be advantageously used in various applications such as, for example, thermal insulation, conveyor belts, transmission belts, flexible hoses and, in particular, in elastomeric compositions for tyres.

Claims

1. Elastomeric terpolymer with a high sulfur content comprising: sulfur in a quantity higher than or equal to 40% by weight with respect to the total weight of said elastomeric terpolymer; a first monomer selected from an aromatic vinyl compound and a second monomer selected from: an aromatic vinyl compound and; a monomer having general formula (I):
CH.sub.2CH(CH.sub.2).sub.y(X).sub.n(X).sub.m(CH.sub.2).sub.xCHCH.sub.2 (I) wherein: X represents a sulfur atom, a selenium atom, or a tellurium atom; y and x, equal to or different from one another, are a whole number ranging from 0 to 4; and n and m, equal to or different from one another, are a whole number ranging from 0 to 3, at least one of n and m being equal to 1; wherein said first monomer and said second monomer are present in a quantity lower than or equal to 60% by weight with respect to the total weight of said elastomeric terpolymer; and wherein said first monomer and said second monomer are different from one another.

2. Elastomeric terpolymer with a high sulfur content according to claim 1, wherein said first monomer is selected from the group consisting of styrene and divinylbenzene.

3. Elastomeric terpolymer with a high sulfur content according to claim 1, wherein said second monomer is selected from the group consisting of styrene, divinylbenzene, allyl disulfide, diallyl disulfide, diallyl trisulfide, and divinyl disulfide.

4. Elastomeric terpolymer with a high sulfur content according to claim 1, wherein said elastomeric terpolymer with a high sulfur content comprises: sulfur in a quantity equal to 60% by weight with respect to the total weight of said elastomeric terpolymer; styrene in a quantity equal to 30% by weight with respect to the total weight of said elastomeric terpolymer; and allyl disulfide in a quantity equal to 10% by weight with respect to the total weight of said elastomeric terpolymer.

5. Elastomeric terpolymer with a high sulfur content according to claim 1, wherein said elastomeric terpolymer with a high sulfur content comprises: sulfur in a quantity equal to 60% by weight with respect to the total weight of said elastomeric terpolymer; styrene in a quantity equal to 10% by weight with respect to the total weight of said elastomeric terpolymer; and divinylbenzene in a quantity equal to 30% by weight with respect to the total weight of said elastomeric terpolymer.

6. Elastomeric terpolymer with a high sulfur content according to claim 1, wherein said elastomeric terpolymer with a high sulfur content has a glass transition temperature (T.sub.g) lower than or equal to +1 C.

7. Elastomeric terpolymer with a high sulfur content according to claim 1, wherein said elastomeric terpolymer with a high sulfur content has an elongation at break higher than or equal to 500%.

8. Process for the preparation of an elastomeric terpolymer with a high sulfur content comprising: (i) melting the sulfur at a temperature ranging from 110 C. to 190 C. for a time ranging from 1 minute to 15 minutes obtaining sulfur in liquid form; (ii) reacting the sulfur in liquid form obtained in stage (i) with a first monomer of an aromatic vinyl compound at a temperature ranging from 110 C. to 190 C. for a time ranging from 1 minute to 15 minutes and subsequently adding a second monomer of an aromatic vinyl compound or from monomers having general formula (I) at a temperature ranging from 110 C. to 190 C. for a time ranging from 1 minute to 15 minutes obtaining a liquid pre-polymer, wherein said first monomer and said second monomer are different from one another; (iii) pouring the liquid pre-polymer obtained in stage (ii) into a mould and maintaining said mould at a temperature ranging from 100 C. to 150 C. for a time ranging from 1 hour to 20 hours obtaining an elastomeric terpolymer with a high sulfur content.

9. Process for the preparation of an elastomeric terpolymer with a high sulfur content according to claim 8, wherein the sulfur used in said stage (i) is elemental sulfur.

10. A method, comprising incorporating the Use of art elastomeric terpolymer with a high sulfur content according to claim 1, in thermal insulation, a conveyor belt, a transmission belt, a flexible hose or a tyre.

11. Elastomeric terpolymer with a high sulfur content according to claim 1, wherein the sulfur is present in a quantity ranging from 55% by weight to 90% by weight with respect to the total weight of said elastomeric terpolymer.

12. Elastomeric terpolymer with a high sulfur content according to claim 1, wherein said first monomer is an aromatic vinyl compound selected from the group consisting of styrene, divinylbenzene, vinyl toluene, tert-butylstyrene, p-methylstyrene, -methylstyrene, -methylstyrene and vinylnaphthalene.

13. Elastomeric terpolymer with a high sulfur content according to claim 1, wherein said second monomer is an aromatic vinyl compound selected from the group consisting of styrene, divinylbenzene, vinyl toluene, tert-butylstyrene, p-methylstyrene, -methylstyrene, -methylstyrene and vinylnaphthalene.

14. Elastomeric terpolymer with a high sulfur content according to claim 1, wherein said first monomer and said second monomer are being present in a quantity ranging from 10% to 45% by weight with respect to the total weight of said elastomeric terpolymer.

15. Process for the preparation of an elastomeric terpolymer with a high sulfur content according to claim 8, wherein the sulfur is melted at a temperature ranging from 120 C. to 170 C. for a time ranging from 2 minutes to 10 minutes.

16. Process for the preparation of an elastomeric terpolymer with a high sulfur content according to claim 8, wherein said first monomer is an aromatic vinyl compound selected from the group consisting of styrene, divinylbenzene, vinyl toluene, tert-butylstyrene, p-methylstyrene, -methylstyrene, -methylstyrene and vinylnaphthalene.

17. Process for the preparation of an elastomeric terpolymer with a high sulfur content according to claim 8, wherein said second monomer is an aromatic vinyl compound selected from the group consisting of styrene, divinylbenzene, vinyl toluene, tert-butylstyrene, p-methylstyrene, -methylstyrene, -methylstyrene and vinylnaphthalene.

18. Process for the preparation of an elastomeric terpolymer with a high sulfur content according to claim 8, wherein the sulfur is reacted at a temperature ranging from 120 C. to 170 C. for a time ranging from 2 minutes to 10 minutes.

19. Process for the preparation of an elastomeric terpolymer with a high sulfur content according to claim 8, wherein the monomer having general formula (I) is selected from the group consisting of allyl disulfide, diallyl disulfide, diallyl trisulfide and divinyl disulfide.

20. Process for the preparation of an elastomeric terpolymer with a high sulfur content according to claim 8, wherein the liquid pre-polymer is poured a mould and maintained at a temperature ranging from 110 C. to 130 C. for a time ranging from 2 hours to 15 hours.

Description

EXAMPLES

Analysis and Characterization Methods

[0047] The analysis and characterization methods below reported have been used.

Thermal Analysis (DSC)

[0048] The DSC (Differential Scanning calorimetry) thermal analysis, for the purpose of determining the glass transition temperature (T.sub.g) of the elastomeric terpolymers obtained, was carried out by means of a Perkin Elmer Pyris differential scanning calorimeter, using the following thermal programme:

[0049] cooling from ambient temperature (T=25 C.) to 60 C. at a rate of 5 C./minute;

[0050] heating from 60 C. to +150 C. at a rate of +10 C./minute (first scan);

[0051] cooling from +150 C. to 60 C. at a rate of 5 C./minute;

[0052] heating from 60 C. to +150 C. at a rate of +10 C./minute (second scan); working under a nitrogen (N.sub.2) stream at 70 ml/minute.

Example 1 (Invention)

Synthesis of Elastomeric Terpolymer With Sulfur (60% by Weight), Styrene (30% by Weight) and Allyl Disulfide (10% by Weight)

[0053] 6 g of pure sulfur [elemental sulfur in orthorhombic crystalline form (S.sub.8) of Sigma-Aldrich] were charged into a 60 ml glass autoclave equipped with a magnetic stirrer: the autoclave was heated to 160 C. and maintained at said temperature for 10 minutes, obtaining the melting of the sulfur, which becomes a yellow liquid. 3 g of liquid styrene (Sigma-Aldrich) was then added, drop by drop, to said liquid: the whole was maintained, under stirring, at 160 C. for 3 minutes, obtaining a solution. 1 g of liquid allyl disulfide (Sigma-Aldrich) was then added, drop by drop, to said solution: the whole was maintained, under stirring, at 160 C. for a further 3 minutes, obtaining a solution which remains still fluid and takes on an intense red colour. The fluid solution thus obtained was poured into a Teflon mould that was closed and heated to 120 C. in an oven: said fluid solution was maintained at said temperature for 12 hours, obtaining an elastomeric terpolymer black in colour and with a translucent appearance.

[0054] Said elastomeric terpolymer was subjected to DSC (Differential Scanning calorimetry) thermal analysis, operating as described above, in order to measure the glass transition temperature (T.sub.g) which was found to be equal to 0.3 C.

[0055] Said elastomeric terpolymer was also subjected to elongation at break, determined according to the standard ISO 37:2017, which was found to be equal to 520%.

Example 2 (Invention)

Synthesis of Elastomeric Terpolymer With Sulfur (60% by Weight), Styrene (10% by Weight) and Divinylbenzene (30% by Weight)

[0056] 6 g of pure sulfur [elemental sulfur in orthorhombic crystalline form (S.sub.8) of Sigma-Aldrich] was charged into a 60 ml glass autoclave equipped with a magnetic stirrer: the autoclave was heated to 160 C. and maintained at said temperature for 10 minutes, obtaining the melting of the sulfur, which becomes a yellow liquid. 1 g of liquid styrene (Sigma-Aldrich) was then added, drop by drop, to said liquid: the whole was maintained, under stirring, at 160 C., for 3 minutes, obtaining a solution. 3 g of liquid divinylbenzene (Sigma-Aldrich) was then added, drop by drop, to said solution: the whole was maintained, under stirring, at 160 C., for a further 3 minutes, obtaining a solution which remains still fluid and takes on an intense red colour. The fluid solution thus obtained was poured into a Teflon mould that was closed and heated to 120 C. in an oven: said fluid solution was maintained at said temperature for 12 hours, obtaining an elastomeric terpolymer black in colour and with a translucent appearance.

[0057] Said elastomeric terpolymer was subjected to DSC (Differential Scanning calorimetry) thermal analysis, operating as described above, for the purpose of measuring the glass transition temperature (T.sub.g), which was found to be equal to +0.96 C.

[0058] Said elastomeric terpolymer was also subjected to elongation at break, determined according to the standard ISO 37:2017, which was found to be equal to 630%.

Example 3 (Comparative)

Synthesis of Elastomeric Copolymer With Sulfur (70% by Weight) and Diallyl Disulfide (30% by Weight)

[0059] 7 g of pure sulfur [elemental sulfur in orthorhombic crystalline form (S.sub.8) of Sigma-Aldrich] was charged into a 60 ml glass autoclave equipped with a magnetic stirrer: the autoclave was heated to 160 C. and maintained at said temperature for 10 minutes, obtaining the melting of the sulfur, which becomes a yellow liquid. 3 g of liquid diallyl disulfide (Sigma-Aldrich) was then added, drop by drop, to said liquid: the whole was maintained, under stirring, at 160 C. for 3 minutes, obtaining a solution which remains still fluid and takes on an intense red colour. The fluid solution thus obtained was poured into a Teflon mould that was closed and heated to 120 C. in an oven: said fluid solution was maintained at said temperature for 12 hours, obtaining an elastomeric copolymer black in colour and with a translucent appearance.

[0060] Said elastomeric copolymer was subjected to DSC (Differential Scanning calorimetry) thermal analysis, operating as described above, for the purpose of measuring the glass transition temperature (T.sub.g), which was found to be equal to 15 C.

[0061] Said elastomeric copolymer was also subjected to elongation at break, determined according to the standard ISO 37:2017, which was found to be equal to 56%.