Process for preparing a sulphur cement product
A process for the preparation of a sulphur cement product is disclosed. Sulphur is mixed with a coupling agent and with a particulate inorganic material at a temperature at which sulphur is molten to obtain a molten sulphur cement product, which is solidified. The coupling agent is supplied as a solid composition comprising the coupling agent and at least 10 wt %, based upon the weight of the solid composition, of carrier material selected from one or more of wax, inorganic filler and polymer. The coupling agent is chosen from the group of organosilanes and organotitanates.
1. A process for the preparation of a sulphur cement product comprising the steps of:
(a) mixing sulphur with a solid composition, comprising at least 10 wt %, based on the weight of the solid composition, a coupling agent and at least 10 wt %, based upon the weight of the solid composition, wax and an inorganic filler, and with a particulate inorganic material at a temperature at which sulphur is molten to obtain a molten sulphur cement product; and
(b) solidifying the molten sulphur cement product;
wherein the coupling agent is chosen from the group of organosilanes and organotitanates.
2. A process according to claim 1 , wherein the sulphur is supplied to step (a) in the form of sulphur pellets.
3. A process according to claim 1 , wherein the coupling agent is an organosilane having the general molecular formula (I):
(P 1 ) 3 Si-A-Si(P 2 ) 3 (I)
Wherein P 1 and P 2 are independently alkoxy, acyloxy, aryloxy, alkyl, aryl and halogen and A is a divalent functional group comprising one or more groups chosen from thiol, sulphide, amine or alkenyl groups or an organosilane having the general molecular formula (III):
(P 3 ) 3 Si-A′ (III)
Wherein P 1 and P 2 are independently alkoxy, acyloxy, aryloxy, alkyl, aryl and halogen and A′ is an univalent functional group comprising one or more groups chosen from thiol, sulphide, amine or alkenyl groups.
4. A process for preparing a solid composition for use in a process as claimed in claim 3 which comprises
(a) providing an aqueous solution of an oligosulphide by reacting a compound of formula (VII):
M m S n (VII)
wherein M is a nitrogen-containing cation, a phosphorus-containing cation or a metal atom, m is 1 or 2 and n is from 1 to 8, or M is hydrogen, m is 2 and n is 1 with molten sulphur;
(b) providing a compound of formula (VIII):
wherein R 1 , R 2 and R 3 are independently chosen from alkoxy, acyloxy, aryloxy, alkyl, aryl and halogen, preferably C1-C6 alkoxy, wherein R 4 is alkylene and wherein X is a leaving group chosen from the group consisting of halogen, carboxylate, nitro, azide, thiocyanate, ammonium, phosphonium and sulfonate, dissolved in a molten hydrophobic wax;
(c) reacting the aqueous solution of step (a) with the molten wax solution of step (b) by mixing the two solutions in the presence of a phase transfer catalyst;
(d) separating the aqueous solution from the molten wax solution and cooling the molten wax solution to a temperature at which the molten wax solidifies to obtain the solid composition.
5. A process according to claim 1 , wherein the coupling agent is an organosilane having the general molecular formula (II):
(R 1 O) 3 Si-A-Si(OR 2 ) 3 (II)
wherein R 1 and R 2 are independently C 1-6 alkyl and A is a divalent functional group comprising one or more groups chosen from thiol, sulphide, amine or alkenyl groups.
6. A process according to claim 5 , wherein A is a polysulphide group of formula —(CH 2 ) x —S y —(CH 2 ) z — wherein x is an integer from 1 to 4, y is an integer from 2 to 8, and z is an integer from 1 to 4.
7. A process according to claim 1 , wherein the solid composition is supplied to step (a) in the form of pellets.
8. A process according to claim 1 , wherein the solid composition comprises from 20 to 70 wt % of the coupling agent, from 20 to 60 wt % of the wax, and from 10 to 50 wt % of the inorganic filler.
9. A process according to claim 8 , wherein the inorganic filler is selected from the group consisting of carbon black, silica, calcium carbonate and calcium silicate.
10. A process according to claim 9 , wherein the inorganic filler comprises particles of average particle size in the range of from 0.1 μm to 0.1 mm.
11. A process for the preparation of a sulphur cement product comprising the steps of:
(a) mixing sulphur with a coupling agent and with a particulate inorganic material at a temperature at which sulphur is molten to obtain a molten sulphur cement product; and
(b) solidifying the molten sulphur cement product;
wherein the coupling agent is chosen from the group of organosilanes and organotitanates, and wherein the coupling agent is supplied as a solid composition comprising the coupling agent and at least 10 wt %, based upon the weight of the solid composition, of carrier material selected from one or more of wax, inorganic filler and polymer, wherein the coupling agent is an organosilane having the general molecular formula (I), and wherein the solid composition comprises wax as carrier material and the coupling agent is prepared by
(a) providing an aqueous solution of an oligosulphide by reacting a compound of formula (VII):
M m S n (VII)
wherein M is a nitrogen-containing cation, a phosphorus-containing cation or a metal atom, m is 1 or 2 and n is from 1 to 8, or M is hydrogen, m is 2 and n is 1 with molten sulphur;
(b) providing a compound of formula (VIII):
wherein R 1 , R 2 and R 3 are independently chosen from alkoxy, acyloxy, aryloxy, alkyl, aryl and halogen, preferably C1-C6 alkoxy, wherein R 4 is alkylene and wherein X is a leaving group chosen from the group consisting of halogen, carboxylate, nitro, azide, thiocyanate, ammonium, phosphonium and sulfonate, dissolved in a molten hydrophobic wax;
(c) reacting the aqueous solution of step (a) with the molten wax solution of step (b) by mixing the two solutions in the presence of a phase transfer catalyst;
(d) separating the aqueous solution from the molten wax solution and cooling the molten wax solution to a temperature at which the molten wax solidifies to obtain the solid composition.
12. A solid composition comprising from 20 to 70 wt % of a coupling agent chosen from the group of organosilanes and organotitanates, from 20 to 60 wt % of wax or polymer, and from 10 to 50 wt % of inorganic filler, wherein the weight percentages are based upon the weight of the solid composition.
13. A solid composition according to claim 12 , comprising from 20 to 50 wt % coupling agent, from 30 to 50 wt % wax and from 15 to 30 wt % inorganic filler.
14. A solid composition according to claim 12 , wherein the coupling agent is an organosilane having the general molecular formula (II):
(R 1 O) 3 Si-A-Si(OR 2 ) 3 (II)
wherein R 1 and R 2 are independently C 1-6 alkyl, and A is a divalent functional group comprising one or more groups chosen from thiol, sulphide, amine or alkenyl groups; wherein the wax is a paraffin wax having a melting point of from 70 to 120° C.; and the inorganic filler is carbon black, calcium carbonate, calcium silicate or titania.
15. A mixture of sulphur pellets and solid composition pellets, wherein the solid composition comprises a at least 10 wt. %, based on the weight of the solid composition, of a coupling agent chosen from the group of organosilanes and organotitanates, and at least 10 wt %, based upon the weight of the solid composition, of carrier material selected from one or more of wax, inorganic filler and polymer.
16. A mixture according to claim 15 , wherein the solid composition pellets consist of a solid composition comprising from 20 to 70 wt % of a coupling agent chosen from the group of organosilanes and organotitanates, from 20 to 60 wt % of wax or polymer, and from 10 to 50 wt % of inorganic filler, wherein the weight percentages are based upon the weight of the solid composition.