Patent Issued for Sulphur Cement Pre-Composition and Process for Preparing Such Sulphur Cement Pre-Composition

By a News Reporter-Staff News Editor at Journal of Engineering -- A patent by the inventors Verbist, Guy Lode Magda Maria (Amsterdam, NL); Van Trier, Rob Aloysius Maria (Eindhoven, NL); Lankshear, Michael David (Amsterdam, NL), filed on June 11, 2008, was cleared and issued on December 4, 2012, according to news reporting originating from Alexandria, Virginia, by VerticalNews correspondents.

Patent number 8323395 is assigned to Shell Oil Company (Houston, TX).

The following quote was obtained by the news editors from the background information supplied by the inventors: "Sulphur cement generally refers to a product comprising at least sulphur and a filler. To improve the properties of the sulphur cement, the sulphur may be modified using a sulphur modifier. Such modifiers are known in the art.

"Usual sulphur cement fillers are particulate inorganic materials.

"Sulphur cement-aggregate composites generally refer to a composite comprising both sulphur cement and aggregate. Examples of sulphur cement-aggregate composites are sulphur mortar, sulphur concrete and sulphur-extended asphalt. Sulphur-extended asphalt is asphalt, i.e. typically aggregate with a binder that contains filler and a residual hydrocarbon fraction, wherein part of the binder has been replaced by sulphur, usually modified sulphur.

"It is known to use organosilane compounds as a stabilising agent in sulphur cement or sulphur cement-aggregate compositions to improve water stability. In U.S. Pat. No. 4,164,428 for example, a modified sulphur composition (often referred to a plasticized sulphur composition) comprising at least 50% by weight of sulphur, a sulphur modifier (often referred to a sulphur plasticizer), a finely divided particulate mineral suspending agent, and an organosilane stabilising agent is disclosed. It is mentioned that suitable organosilanes have the general molecular formula R--Si(OR').sub.3, wherein R' is a low molecular weight alkyl group and R is an organic radical having at least one functional group, usually bonded to the silicon atom by a short alkyl chain. Gamma-mercaptopropyltrimethoxysilane is mentioned as a preferred organosilane.

"In U.S. Pat. No. 4,376,830 a sulphur cement-aggregate composition comprising a sulphur cement and an aggregate containing an expansive clay and processes for preparing such compositions are disclosed. The processes, and resulting compositions, are characterised by the addition of certain organosilane compounds in the composition prior to solidifying (cooling) the composition. It is mentioned that suitable organosilanes have the formula Z--Si(R.sup.1R.sup.2R.sup.3), wherein R.sup.1, R.sup.2 and R.sup.3 may be lower alkoxy groups and Z is an organic radical attached to Si via a carbon atom and has at least one molten-sulphur reactive group. Z may for example be mercaptoalkyl. Gamma-mercaptopropyltrimethoxysilane is mentioned as a preferred organosilane. Gamma-mercaptopropyltrimethoxysilane is very toxic and has a very unpleasant smell. There is a need in the art for further stabilizing agents, which improve the water stability of sulphur cement products."

In addition to the background information obtained for this patent, VerticalNews journalists also obtained the inventors' summary information for this patent: "It has now been found that a stabilizing agent chosen from a group of organotitanates can be used to prepare sulphur cement products.

"Accordingly, the present invention provides a sulphur cement pre-composition, comprising sulphur and at least an organotitanate, which organotitanate is of the general molecular formula:

"##STR00001## wherein

"R.sub.1 is C.sub.nH.sub.(2n)--S.sub.aR.sub.4 or C.sub.mH.sub.(2m+1) and n is an integer in the range of from 1 to 4, m is an integer in the range of from 1 to 30 and a is an integer in the range of from 2 to 8, R.sub.4 is S, H, or C.sub.pH.sub.(2p+1) and p is an integer in the range of from 1 to 8,

"XO is an alkoxy or neoalkoxy group, and

"R.sub.2 and R.sub.3 are, independently, a C.sub.nH.sub.(2n)--S.sub.aR.sub.4, alkyl, neoalkyl, acyl or aryl group.

"The invention in a further aspect provides a sulphur cement pre-composition, comprising sulphur and at least an organotitanate, which organotitanate is of the general molecular formula:

"##STR00002## wherein

"R.sub.5 is C.sub.nH.sub.(2n)--S.sub.a--C.sub.n'H.sub.(2n') and n and n' each are, independently, an integer in the range of from 1 to 4 and a is an integer in the range of from 2 to 8,

"XO and X'O each are, independently, an alkoxy or neoalkoxy group, and

"R.sub.2, R.sub.3, R.sub.6, and R.sub.7 each are, independently, a C.sub.nH.sub.(2n)--S.sub.aR.sub.4, alkyl, neoalkyl, acyl or aryl group wherein R.sub.4 is S, H, or C.sub.pH.sub.(2p+1) and p is an integer in the range of from 1 to 8.

"The invention in a further aspect provides a process for the preparation of a sulphur cement pre-composition according to the invention, comprising admixing sulphur with at least an organotitanate in an amount of at least 0.05 wt % based on the weight of the total composition to obtain a sulphur cement pre-composition, in which process the organotitanate is of the general molecular formula as defined hereinabove.

"The invention in an even further aspect provides a process for the preparation of a sulphur cement product comprising the following steps: (a) admixing at least sulphur, and organotitanate as defined hereinabove and 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.

"The invention in a yet further aspect provides a process for the preparation of sulphur cement product comprising the following steps: (a) admixing at least a particulate inorganic material and organotitanate as defined hereinabove and allowing the organotitanate to react with the particulate inorganic material; (b) admixing, after step (a), elemental sulphur with the particulate inorganic material at a temperature at which sulphur is liquid to obtain an admixture comprising molten sulphur and particulate inorganic material; and solidifying the admixture to obtain a sulphur cement product.

"The invention in a still further aspect provides a sulphur cement product obtainable by a process for the preparation of a sulphur cement product according to the invention.

"The invention in another aspect provides the use of an organotitanate as defined hereinabove as stabilizing agent in sulphur cement, sulphur mortar, sulphur concrete or sulphur-extended asphalt.

"The invention in even another aspect provides the use of a sulphur cement pre-composition according to the invention in sulphur cement, sulphur mortar, sulphur concrete or sulphur-extended asphalt.

"Reference herein to a sulphur cement pre-composition is to a composition, which after addition of at least one of sulphur or a particulate inorganic material forms a sulphur cement product, e.g. a sulphur cement, a sulphur mortar, sulphur concrete and sulphur-extended asphalt."

URL and more information on this patent, see: Verbist, Guy Lode Magda Maria; Van Trier, Rob Aloysius Maria; Lankshear, Michael David. Sulphur Cement Pre-Composition and Process for Preparing Such Sulphur Cement Pre-Composition. U.S. Patent Number 8323395, filed June 11, 2008, and issued December 4, 2012. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=90&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=4475&f=G&l=50&co1=AND&d=PTXT&s1=20121204.PD.&OS=ISD/20121204&RS=ISD/20121204

Keywords for this news article include: Shell Oil Company.

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