The present invention relates to a rubber stock for bead wire compounds comprising

xe2x80x9cBeadxe2x80x9d as used herein means that part of a tire comprising an annular tensile member wrapped by ply cords and shaped, with or without other reinforcement elements such as flippers, chippers, apexes, toe guards and chafers, to fit the design rim.
A frequent problem in making a tire having a bead is maintaining good adhesion between the rubber and the bead. A conventional method in promoting the adhesion between the rubber and the reinforcement in the bead is to pre-treat the reinforcing wire with a mixture of a rubber latex and a phenol-formaldehyde condensation product wherein the phenol is almost always resorcinol. This is the so-called xe2x80x9cRFLxe2x80x9d (resorcinol-formaldehyde-latex) method. An alternative method of promoting such adhesion is to generate the resin in-situ (in the vulcanized rubber/textile matrix) by compounding a phenol-formaldehyde condensation product (hereinafter referred to as the xe2x80x9cin-situ methodxe2x80x9d). The components of the condensation product consist of a methylene acceptor and a methylene donor. The most common methylene donors include N-(substituted oxymethyl) melamine, hexamethylene tetramine or hexamethoxy methyl melamine. A common methylene acceptor is a dihydroxy benzene compound such as resorcinol. The in-situ method has been found to be fairly effective where the reinforcing material is steel wire since pre-treatment of the wire with the RFL system has been observed as being largely ineffective. Unfortunately, the products using the in-situ method has still fallen short of the demands of the consumer.
The purpose of the present invention is to further improve the adhesion between the wire reinforcement in the bead and its rubber environment to satisfy this shortcoming in the existing technology.
The present invention relates to rubber stocks particularly suited for bead wire compounds for use in tires. The rubber stock of the present invention is characterized by having two or more diene rubbers. At least one of the diene rubbers is a carboxylated acrylonitrile-diene rubber having an acrylonitrile content ranging from about 15 to 45 percent by weight. The rubber stock also contains a methylene acceptor and methylene donor.
In addition, there is disclosed a pneumatic tire having a pair of beads where the beads are coated with the bead wire compound of the present invention.
There is disclosed a rubber stock for bead wire compounds comprising
(A) based on 100 parts by weight of rubber
(1) from about 5 to about 40 weight percent of a carboxylated acrylonitrile-diene rubber having an acrylonitrile content ranging from about 15 to 45 percent by weight; and
(2) from about 60 to about 95 weight percent of a non-carboxylated rubber selected from the group consisting of natural rubber, polyisoprene, polybutadiene, styrene-butadiene rubber, styrene-isoprene-butadiene rubber, styrene-isoprene rubber, isoprene-butadiene rubber and mixtures thereof;
(B) from about 0.1 to about 10 phr of a methylene acceptor; and
(C) from about 0.1 to about 10 phr of a methylene donor.
One essential component contained in the present invention is a carboxylated acrylonitrile rubber. Based on 100 parts by weight of the total rubber in the rubber composition, from 5 to 40 parts by weight, is the carboxylated acrylonitrile rubber. Preferably, from 10 to 20 parts by weight is the carboxylated acrylonitrile rubber.
The present invention involves the use of a carboxylated acrylonitrile rubber or carboxylated acrylonitrile/diene polymer having an acrylonitrile content ranging from about 15 to about 45 percent by weight. Preferably, the acrylonitrile (ACN) content ranges from 18 to 35 percent by weight. The acrylonitrile/diene copolymers are intended to include acrylonitrile/butadiene copolymers and acrylonitrile/isoprene copolymers.
The carboxylated nitrile rubbers contain chain linkages derived from unsaturated carboxylic acids of the acrylic acid type (unsaturated carboxylic acid monomers). Some representative examples of unsaturated carboxylic acids of the acrylic acid type include acrylic acid, methacrylic acid, sorbic acid, xcex2-acryloxypropanoic acid, ethacrylic acid, 2-ethyl-3-propyl acrylic acid, vinyl acrylic acid, cinnamic acid, maleic acid, fumaric acid and the like. Carboxylated nitrile rubbers generally contain from about 0.75 percent to 15 percent by weight chain linkages (repeat units) which are derived from unsaturated carboxylic acid monomers.
The carboxylic nitrile rubbers can be synthesized using any conventional polymerization technique. Emulsion polymerization of carboxylated nitrile elastomers is generally preferred and is used almost exclusively in industrial production. This type of a synthesis generally utilizes a charge composition comprising water, monomers, an initiator and an emulsifier (soap). Such polymerizations can be run over a very wide temperature range from about 0xc2x0 C. to as high as 100xc2x0 C. It is more preferred for these polymerizations to be run at a temperature from about 5xc2x0 C. to 60xc2x0 C.
The amount of carboxylic acid monomer (unsaturated carboxylic acid of the acrylic acid type) incorporated in a carboxylated nitrile rubber may be varied over a wide range. The monomer charge ratio between the carboxylic monomer and the comonomers employed in a polymerization may also be varied over a very wide range. Generally, the charge composition used in the synthesis of carboxylated nitrile rubbers will contain 60 percent to 75 percent by weight butadiene, 15 percent to 40 percent by weight of acrylonitrile and 1 percent to 15 percent by weight methacrylic acid, based upon the total monomer charge. A typical charge composition for a carboxylated nitrile rubber will contain 65 to 69 weight butadiene, 24 to 28 weight percent acrylonitrile and 5 to 9 weight percent methacrylic acid.
The emulsifiers used in the polymerization of such polymers may be charged at the outset of the polymerization or may be added incrementally or by proportioning as the reaction proceeds. Generally, anionic emulsifier systems provide good results; however, any of the general types of anionic, cationic or nonionic emulsifiers may be employed in the polymerization.
Among the anionic emulsifiers that can be employed in emulsion polymerizations are fatty acids and their alkali metal soaps such as caprylic acid, capric acid, pelargonic acid, lauric acid, undecylic acid, myristic acid, palmitic acid, margaric acid, stearic acid, arachidic acid and the like; amine soaps of fatty acids such as those formed from ammonia, mono- and dialkyl amines, substituted hydrazines, guanidine and various low molecular weight diamines; chain-substituted derivatives of fatty acids such as those having alkyl substituents; naphthenic acids and their soaps and the like; sulfuric esters and their salts, such as the tallow alcohol sulfates, coconut alcohol sulfates, fatty alcohol sulfates, such as oleyl sulfate, sodium lauryl sulfate and the like; sterol sulfates; sulfates of alkylcyclohexanols, sulfation products of lower polymers of ethylene as C10 to C20 straight chain olefins, and other hydrocarbon mixtures, sulfuric esters of aliphatic and aromatic alcohols having intermediate linkages, such as ether, ester or amide groups such as alkylbenzyl (polyethyleneoxy) alcohols, the sodium salt or tridecyl ether sulfate; alkane sulfonates, esters and salts, such as alkylchlorosulfonates with the general formula RSO2Cl, wherein R is an alkyl group having from 1 to 20 carbon atoms, and alkylsulfonates with the general formula RSO2xe2x80x94OH, wherein R is an alkyl group having from 1 to 20 carbon atoms; sulfonates with intermediate linkages such as ester and ester-linked sulfonates such as those having the formula RCOOC2H4SO3H and ROOCxe2x80x94CH2xe2x80x94SO3H, wherein R is an alkyl group having from 1 to 20 carbon atoms such as dialkyl sulfosuccinates; ester salts with the general formula:
wherein Rxe2x80x2 is an alkyl group having from 1 to 20 carbon atoms; alkaryl sulfonates in which the alkyl groups contain preferably from 10 to 20 carbon atoms, e.g. dodecylbenzenesulfonates, such as sodium dodecylbenzenesulfonate; alkyl phenol sulfonates; sulfonic acids and their salts such as acids with the formula R6SO3Na, wherein Rxe2x80x2 is an alkyl and the like; sulfonamides, sulfamido methylenesulfonic acids; rosin acids and their soaps; sulfonated derivatives of rosin and rosin oil; and lignin sulfonates and the like.
Rosin acid soap has been used with good success at a concentration of about 5 percent by weight in the initial charge composition used in the synthesis of carboxylated elastomers. Of rosin acids, about 90 percent are isomeric with abietic acid and the other 10 percent is a mixture of dehydro abietic acid and dihydro abietic acid.
The polymerization of these carboxylated nitrile rubbers may be initiated using free radical catalysts, ultraviolet light or radiation. To ensure a satisfactory polymerization rate, uniformity and a controllable polymerization, free radical initiators are generally used with good results. Free radical initiators which are commonly used include the various peroxygen compounds such as potassium persulfate, ammonium persulfate, benzoyl peroxide, hydrogen peroxide, di-t-butyl peroxide, dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, decanoyl peroxide, lauroyl peroxide, cumene hydroperoxide, p-menthane hydroperoxide, t-butylhydroperoxide, acetyl acetone peroxide, methyl ethyl ketone peroxide, succinic acid peroxide, dicetyl peroxydicarbonate, t-butyl peroxyacetate, t-butyl peroxymaleic acid, t-butyl peroxybenzoate, acetyl cyclohexyl sulfonyl peroxide and the like; the various azo compounds such as 2-t-butylazo-2-cyanopropane, dimethyl azodiisobutyrate, azodiisobutyronitrile, 2-t-butylazo-1-cyanocyclohexane, 1-t-amylazo-1-cyanocyclohexane and the like; the various alkyl perketals, such as 2,2-bis-(t-butylperoxy)butane, ethyl 3,3-bis(t-butylperoxy)butyrate, 1,1-di-(t-butylperoxy)cyclohexane and the like. Cumene hydroperoxide can be used as an initiator to obtain very good results in the polymerization of carboxylated nitrile rubber.
The emulsion polymerization system used in the synthesis of carboxylated nitrile rubbers can be treated at the desired degree of conversion with shortstopping agents, such as hydroquinone. Typical shortstopping agents will not interfere with the action of the succinic acid derivative salts as scorch inhibitors. Typical stabilizing agents and standard antioxidants can also be added to the emulsion of a carboxylated nitrile rubber.
After the emulsion polymerization has been completed, most conventional coagulating techniques for carboxylated nitrile rubbers can be employed. A review of coagulation techniques for nitrile rubbers is presented in Hofmann, Werner xe2x80x9cNitrile Rubber,xe2x80x9d Rubber Chemistry and Technology, Vol. 37, No. 2, Part 2 (April to June 1964), Pages 94 through 96, which is incorporated herein by reference. Normally such latexes are coagulated with reagents which ensure the preservation of the carboxyl groups of the elastomers as acidic moieties. Coagulation with acid or blends of salts with acids is usually very satisfactory. For example, sulfuric acid, hydrochloric acid, blends of sodium chloride with sulfuric acid and blends of hydrochloric acids with methanol are very effective as coagulating agents for carboxylated rubber emulsions. Calcium chloride solutions which are free of calcium hydroxide have also been used as coagulants with great success.
After coagulation, washing may be employed to remove excess soap and/or electrolyte from the carboxylated rubber. Sometimes washing is also useful in adjusting the pH of the carboxylated elastomer that has been synthesized. After washing, if it is desired, the elastomer can be dewatered. If it is desirable to do so, the carboxylated rubber can also be dried and baled after dewatering using conventional techniques.
An example of commercially available carboxylated nitrile rubber is CHEMIGUM(copyright) NX-775 (Bd/ACN-67/26 with 7 percent carboxylic acid) marketed by Nippon Zeon. This carboxylated copolymer contains approximately 0.5 to 10 percent by weight terminal carboxyl groups relative to the total amount of carboxylic acid.
From about 60 to about 95 weight percent of the total rubber in the rubber stock is a non-carboxylated rubber. Preferably, from 80 to 90 percent by weight of the total rubber is a non-carboxylated rubber.
Representative examples of non-carboxylated rubber which may be used include natural rubber, polyisoprene, polybutadiene, styrene-butadiene rubber, styrene-isoprene-butadiene rubber, styrene-isoprene rubber, isoprene-butadiene rubber and mixtures thereof. Preferably, the rubbers are natural rubber, styrene-butadiene rubber and polybutadiene.
According to an embodiment of the present invention, the rubber stock contains a xe2x80x9cmethylene donorxe2x80x9d and a xe2x80x9cmethylene acceptorxe2x80x9d. The term xe2x80x9cmethylene acceptorxe2x80x9d is known to those skilled in the art and is used to describe the reactant to which the methylene donor reacts to form what is believed to be a methylol monomer. The condensation of the methylol monomer by the formation of a methylene bridge produces the resin. The initial reaction that contributes the moiety that later forms into the methylene bridge is the methylene donor wherein the other reactant is the methylene acceptor. Representative compounds which may be used as a methylene acceptor are resorcinol, unmodified phenol novolak resins, modified phenol novolak resin, resorcinol novolak resins and mixtures thereof. Examples of modified phenol novolak resins include cashew nut oil modified phenol novolak resin, tall oil modified phenol novolak resin and alkyl modified phenol novolak resin.
The amount of methylene acceptor that is included in the rubber stock may vary depending on the type of rubber, the particular methylene acceptor, the particular methylene donor and the desired physical properties, i.e., adhesion and tear. Generally speaking, the amount of methylene acceptor may range from about 0.1 to about 10 phr. Preferably, the amount of methylene acceptor ranges from about 0.5 to about 5.0 phr.
The rubber stock of the present invention contains a methylene donor which is suitable for reaction with the methylene acceptor. Examples of methylene donors which are suitable for use in the present invention include hexamethylenetetramine, hexaethoxymethylmelamine, hexamethoxymethylmelamine, lauryloxymethoxypyridinium chloride, ethoxymethylpyridinium chloride, trioxan hexamethoxymethylmelamine, the hydroxy groups of which may be esterified or partially esterified, and polymers of the methylene donors may be N-substituted oxymethylmelamines of the formula:
wherein X is an alkyl having from 1 to 8 carbon atoms, R, R1, R2, R3, and R4 are individually selected from the group consisting of hydrogen, an alkyl having from 1 to 8 carbon atoms, the group xe2x80x94CH2OX or their condensation products. Specific methylene donors include hexakis-(methoxymethyl)melamine, N,Nxe2x80x2,Nxe2x80x3-trimethyl/N,Nxe2x80x2,Nxe2x80x3-trimethylolmelamine, hexamethylolmelamine, N,Nxe2x80x2,Nxe2x80x3-dimethylolmelamine, N-methylolmelamine, N,Nxe2x80x2-dimethylolmelamine, N,Nxe2x80x2,Nxe2x80x3-tris(methoxymethyl)melamine and N,Nxe2x80x2Nxe2x80x3-tributyl-N,Nxe2x80x2,Nxe2x80x3-trimethylol-melamine. The N-methylol derivatives of melamine are prepared by known methods.
The amount of methylene acceptor that is present in the rubber stock may vary depending on the type of rubber, the particular methylene acceptor, the particular methylene donor and the desired physical properties, i.e., adhesion and tear. Generally speaking, the amount of methylene donor may range from about 0.1 to about 10 phr. Preferably, the amount of methylene donor ranges from about 0.5 to about 5.0 phr.
The weight ratio of methylene donor to methylene acceptor can vary. Generally speaking, the weight ratio will range from about 1:10 to about 10:1. Preferably, the weight ratio ranges from about 1:3 to 3:1.
The term xe2x80x9cphrxe2x80x9d as used herein, and according to conventional practice, refers to xe2x80x9cparts by weight of a respective material per 100 parts by weight of rubber, or elastomer.xe2x80x9d
The bead wire compound should contain a sufficient amount of filler to contribute a reasonably high modulus and high resistance to tear. The filler may be added in amounts ranging from 50 to 250 phr. Preferably, the filler is present in an amount ranging from 90 to 160 phr. Fillers include silica, carbon black, clays, calcium silicate and titanium dioxide. If carbon black is present, the amount of carbon black may vary. It is to be appreciated that a silica coupler may be used in conjunction with a carbon black, namely pre-mixed with a carbon black prior to addition to the rubber composition, and such carbon black is to be included in the aforesaid amount of carbon black for the rubber composition formulation.
The commonly employed siliceous pigments used in rubber compounding applications can be used as the silica in this invention, including pyrogenic and precipitated siliceous pigments (silica) and aluminosilicates, although precipitated silicas are preferred. The siliceous pigments preferably employed in this invention are precipitated silicas such as, for example, those obtained by the acidification of a soluble silicate, e.g., sodium silicate.
Such silicas might be characterized, for example, by having a BET surface area, as measured using nitrogen gas, preferably in the range of about 40 to about 600, and more usually in a range of about 50 to about 300 square meters per gram. The BET method of measuring surface area is described in the Journal of the American Chemical Society, Volume 60, page 304 (1930).
The silica may also be typically characterized by having a dibutylphthalate (DBP) absorption value in a range of about 100 to about 400, and more usually about 150 to about 300.
Further, the silica, as well as the aforesaid alumina and aluminosilicate may be expected to have a CTAB surface area in a range of about 100 to about 220. The CTAB surface area is the external surface area as evaluated by cetyl trimethylammonium bromide with a pH of 9. The method is described in ASTM D 3849 for set up and evaluation. The CTAB surface area is a well known means for characterization of silica.
Mercury surface area/porosity is the specific surface area determined by Mercury porosimetry. For such technique, mercury is penetrated into the pores of the sample after a thermal treatment to remove volatiles. Set-up conditions may be suitably described as using a 100 mg sample; removing volatiles during 2 hours at 105xc2x0 C. and ambient atmospheric pressure; ambient to 2000 bars pressure measuring range. Such evaluation may be performed according to the method described in Winslow, Shapiro in ASTM bulletin, p.39 (1959) or according to DIN 66133. For such an evaluation, a CARLO-ERBA Porosimeter 2000 might be used.
The average mercury porosity specific surface area for the silica should be in a range of about 100 to 300 m2/g.
A suitable pore-size distribution for the silica, alumina and aluminosilicate according to such mercury porosity evaluation is considered herein to be five percent or less of its pores have a diameter of less than about 10 nm; 60 to 90 percent of its pores have a diameter of about 10 to about 100 nm; 10 to 30 percent of its pores have a diameter of about 100 to about 1000 nm; and 5 to 20 percent of its pores have a diameter of greater than about 1000 nm.
The silica might be expected to have an average ultimate particle size, for example, in the range of 0.01 to 0.05 micron as determined by the electron microscope, although the silica particles may be even smaller, or possibly larger, in size.
Various commercially available silicas may be considered for use in this invention such as, only for example herein, and without limitation, silicas commercially available from PPG Industries under the Hi-Sil trademark with designations 210, 243, etc; silicas available from Rhone-Poulenc, with, for example, designations of Z1165MP and Z165GR and silicas available from Degussa AG with, for example, designations VN2, VN3, BV3380GR, etc, and silicas available from Huber, for example Huber Sil 8745.
The silica fillers are used with sulfur containing organosilicon compounds. Examples of suitable sulfur containing organosilicon compounds are of the formula:
Zxe2x80x94Alkxe2x80x94Snxe2x80x94Alkxe2x80x94Zxe2x80x83xe2x80x83III
in which Z is selected from the group consisting of
where R5 is an alkyl group of 1 to 4 carbon atoms, cyclohexyl or phenyl; R6 is alkoxy of 1 to 8 carbon atoms, or cycloalkoxy of 5 to 8 carbon atoms; Alk is a divalent hydrocarbon of 1 to 18 carbon atoms and n is from 2 to 8.
Specific examples of sulfur containing organosilicon compounds which may be used in accordance with the present invention include: 3,3xe2x80x3-bis(triethoxysilylpropl) disulfide, 3,3xe2x80x2-bis(triethoxysilylpropyl) tetrasulfide, 3,3xe2x80x2-bis(triethoxysilylpropyl) octasulfide, 3,3xe2x80x2-bis(trimethoxysilylpropyl) tetrasulfide, 2,2xe2x80x2-bis(triethoxysilylethyl) tetrasulfide, 3,3xe2x80x2-bis(trimethoxysilylpropyl) trisulfide, 3,3xe2x80x2-bis(tethoxysilylpropyl) trisulfide, 3,3xe2x80x2-bis(trimethoxysilylpropyl) hexasulfide, 3,3xe2x80x2-bis(trimethoxysilylpropyl) octasulfide, 3,3xe2x80x2-bis(trioctoxysilylpropyl) tetrasulfide, 3,3xe2x80x2-bis(tri-2xe2x80x3-ethylhexoxysilylpropyl) trisulfide, 3,3xe2x80x2-bis(triisooctoxysilylpropyl) tetrasulfide, 2,2xe2x80x2-bis(methoxy diethoxy silyl ethyl) tetrasulfide, 2,2xe2x80x2-bis(tripropoxysilylethyl) pentasulfide, 3,3xe2x80x2-bis(tricyclonexoxysilylpropyl) tetrasulfide, 3,3xe2x80x2-bis(tricyclopentoxysilylpropyl) trisulfide, 2,2xe2x80x2-bis(tri-2xe2x80x3-methylcyclohexoxysilylethyl) tetrasulfide, bis(trimethoxysilylmethyl) tetrasulfide, 3-methoxy ethoxy propoxysilyl 3xe2x80x2-diethoxybutoxy-silylpropyltetrasulfide, 2,2xe2x80x2-bis(dimethyl sec.butoxysilylethyl) trisulfide, 3,3xe2x80x2-bis(methyl butylethoxysilylpropyl) tetrasulfide, 3,3xe2x80x2-bis(di t-butylmethoxysilylpropyl) tetrasulfide, 2,2xe2x80x2-bis(phenyl methyl methoxysilylethyl) trisulfide, 3,3xe2x80x2-bis(diphenyl isopropoxysilylpropyl) tetrasulfide, 3,3xe2x80x2-bis(dimethyl ethylmercaptosilylpropyl) tetrasulfide, 2,2xe2x80x2-bis(methyl dimethoxysilylethyl) trisulfide, 2,2xe2x80x2-bis(methyl ethoxypropoxysilylethyl) tetrasulfide, 3,3xe2x80x2-bis(diethyl methoxysilylpropyl) tetrasulfide, 3,3xe2x80x2-bis(butyl dimethoxysilylpropyl) trisulfide, 3,3xe2x80x2-bis(phenyl dimethoxysilylpropyl) tetrasulfide, 3-phenyl ethoxybutoxysilyl 3xe2x80x2-trimethoxysilylpropyl tetrasulfide, 4,4xe2x80x2-bis(trimethoxysilylbutyl) tetrasulfide, 6,6xe2x80x2-bis(triethoxysilylhexyl) tetrasulfide, 18,18xe2x80x2-bis(trimethoxysilyloctadecyl) tetrasulfide, 18,18xe2x80x2-bis(tripropoxysilyloctadecenyl) tetrasulfide, 4,4xe2x80x2-bis(trimethoxysilyl-buten-2-yl) tetrasulfide, 4,4xe2x80x2-bis(trimethoxysilylcyclohexylene) tetrasulfide, 5,5xe2x80x2-bis(dimethoxymethylsilylpentyl) trisulfide, and 3,3xe2x80x2-bis(trimethoxysilyl-2-methylpropyl) tetrasulfide.
The preferred sulfur containing organosilicon compounds are the 3,3xe2x80x2-bis(trimethoxy or triethoxy silylpropyl) sulfides. The most preferred compound is 3,3xe2x80x2-bis(triethoxysilylpropyl) tetrasulfide. Preferably Z is
where R6 is an alkoxy of 2 to 4 carbon atoms, with 2 carbon atoms being particularly preferred; Alk is a divalent hydrocarbon of 2 to 4 carbon atoms with 3 carbon atoms being particularly preferred; and n is an integer of from 2 to 5.
The amount of the above sulfur containing organosilicon compound in a rubber composition will vary depending on the level of silica that is used. Generally speaking, the amount of the compound of formula III will range from 0.01 to 0.1 parts by weight per part by weight of the silica. Preferably, the amount will range from 0.04 to 0.08 parts by weight per part by weight of the silica.
Representative examples of reinforcing type carbon blacks(s), for this invention, include N326, N330, N332, N339, N343, N347, N351, N358, N375, N539, N550, N582, N650, N660, N683, N754, N762, N765, N774, and N787. Such types of carbon black are characterized through Iodine absorption ranging from 9 to 100 g/kg and DBP number ranging from 34 to 140 cm3/100 g.
As known to one skilled in the art, in order to cure a rubber stock, one needs to have a sulfur vulcanizing agent. Examples of suitable sulfur vulcanizing agents include elemental sulfur (free sulfur) or sulfur donating vulcanizing agents, for example, an amine disulfide, polymeric polysulfide or sulfur olefin adducts. Preferably, the sulfur vulcanizing agent is elemental sulfur. The amount of sulfur vulcanizing agent will vary depending on the components of the rubber stock and the particular type of sulfur vulcanizing agent that is used. Generally speaking, the amount of sulfur vulcanizing agent ranges from about 0.1 to about 8 phr with a range of from about 1.5 to about 6 being preferred.
Conventional rubber additives may be incorporated in the rubber stock of the present invention. The additives commonly used in rubber stocks include plasticizers, curatives, processing oils, retarders, antiozonants, antioxidants and the like. Plasticizers are conventionally used in amounts ranging from about 2 to about 50 phr with a range of about 5 to about 30 phr being preferred. The amount of plasticizer used will depend upon the softening effect desired. Examples of suitable plasticizers include aromatic extract oils, petroleum softeners including asphaltenes, naphthenic oil, saturated and unsaturated hydrocarbons and nitrogen bases, coal tar products, cumarone-indene resins and esters such as dibutylphthalate and tricresyl phosphate. Materials used in compounding which function as an accelerator-activator includes metal oxides such as zinc oxide, magnesium oxide and litharge which are used in conjunction with acidic materials such as fatty acid, for example, stearic acid, oleic acid, murastic acid, and the like. The amount of the metal oxide may range from about 1 to about 10 phr with a range of from about 2 to about 8 phr being preferred. The amount of fatty acid which may be used may range from about 0.25 phr to about 5.0 phr with a range of from about 0.5 phr to about 2 phr being preferred.
Accelerators may be used to control the time and/or temperature required for vulcanization of the rubber stock. As known to those skilled in the art, a single accelerator may be used which is present in amounts ranging from about 0.2 to about 2.0 phr. In the alternative, combinations of two or more accelerators may be used which consist of a primary accelerator which is generally used in a larger amount (0.3 to about 2.0 phr), and a secondary accelerator which is generally used in smaller amounts (0.05 to about 0.50 phr) in order to activate and improve the properties of the rubber stock. Combinations of these accelerators have been known to produce synergistic effects on the final properties and are somewhat better than those produced by use of either accelerator alone. Delayed action accelerators also are known to be used which are not affected by normal processing temperatures and produce satisfactory cures at ordinary vulcanization temperatures. Suitable types of accelerators include amines, disulfides, guanidines, thioureas, thiazoles, thiurams, sulfenamides, dithiocarbamates and the xanthates. Examples of specific compounds which are suitable include zinc diethyl-dithiocarbamate, 4,4xe2x80x2-dithiodimorpholine, N,N-di-methyl-S-tert-butylsulfenyldithiocarbamate, tetramethylthiuram disulfide, 2,2xe2x80x2-dibenzothiazyl disulfide, butyraldehydeaniline mercaptobenzothiazole, N-oxydiethylene-2-benzothiazolesulfenamide and N-cyclohexyl-2-benzothiazolesulfenamide. Preferably, the accelerator is a sulfenamide.
A class of compounding materials known as scorch retarders are commonly used. Phthalic anhydride, salicyclic acid, sodium acetate and N-cyclohexyl thiophthalimide are known retarders. Retarders are generally used in an amount ranging from about 0.1 to 0.5 phr.
Preformed phenol-formaldehyde type resins may be used in the rubber stock and are generally present in an amount ranging from about 1.0 to about 5.0 phr, with a range of from about 1.5 to about 3.5 phr being preferred.
Conventionally, antioxidants and some times antiozonants, hereinafter referred to as antidegradants, are added to rubber stocks. Representative antidegradants include monophenols, bisphenols, thiobisphenols, polyphenols, hydroquinone derivatives, phosphites, thioesters, naphthyl amines, diphenyl-p-phenylenediamines, diphenylamines and other diaryl amine derivatives, para-phenylenediamines, quinolines and mixtures thereof. Specific examples of such antidegradants are disclosed in The Vanderbilt Rubber Handbook (1990), Pages 282 through 286. Antidegradants are generally used in amounts from about 0.25 to about 5.0 phr with a range of from about 1.0 to about 3.0 phr being preferred.
The rubber stock of the present invention has a particular utility in a composite with reinforcing material as a wire coat stock or ply coat stock. Examples of such composites include tires, belts or hoses. In particular, the rubber stock of the present invention has utility as a wire coat stock or ply coat stock for use in tires.
The present invention may be better understood by reference to the following example in which the parts or percentages are by weight unless otherwise indicated.


Storable compositions and slurries for cementing oil and gas wells are described which comprise blast-furnace slag besides other additives which are usual in the cementing technique. The compositions and slurries are insufficiently activated (or are activated immediately before introducing them into the well), so that they can be stored for at least 72 hours (alternatively they may be stored indefinitely) without the setting of the composition and dispense with the addition of activation inhibitors. The use of the compositions and slurries in the cementing of oil and gas wells is also described.

The present invention relates to compositions and slurries for cementing oil and gas wells as well as to the use of such slurries in those wells, and specifically to compositions and slurries containing blast furnace slag to be used in water-based fluids as hydraulic material, in the absence of set inhibitors, such slurries being storable at ambient temperature.
The usual procedure for drilling an oil and gas well comprises drilling the well using a drilling fluid. Then, a casing is introduced in the well and a cementitious slurry is placed in the annulus between the outer portion of the casing and the borehole wall. The purpose of the cementitious slurry is to harden and provide efficient sealing between the casing and the well. The outer shell of hardened cement impedes or inhibits the fluid communication among the various formations penetrated by the well. Besides providing isolation among zones, the cement contacts the casing and provides mechanical support and strength to axial movement through the adherence developed between the interfaces of cement and casing as well as between the interfaces of the cement and the formation.
Besides the proper features of adherence between the cement and the casing and between the cement and the formation, of compatibility between the cementitious slurry and the drilling fluid, of the compressive strength and of the rheological parameters, another important feature is the set time (or hardening time) of the slurry compositions. Normally, slurries contain additives for the control of set time (accelerators and retarders) and rheology-modifying additives.
The set activating additives are used in the cementitious slurries aiming at avoiding long waiting times (up to ca. 24 hours) until the slurry hardens, after the slurry being placed in the desired site of the annulus of the well.
The patent literature is abundant in publications dealing with applications of blast furnace slag together with water based drilling fluids.
Thus, U.S. Pat. No. 5,058,679 teaches the in situ solidification of water based fluids by adding blast furnace slag, additives for controlling the set time, as well as rheology modifiers. After addition for example 50 to 400 lb/bbl slag, the drilling fluid is displaced to the annulus and left to harden. The setting time of the drilling fluid treated with slag may be varied according to the temperature conditions of the well and the requirements for the displacing time. Set times are controlled between around one hour and up to several days for temperatures between 40 and 400xc2x0 F. (4 and 204xc2x0 C.).
U.S. Pat. No. 5,409,064 teaches a composition and method for cementing a well by combining ingredients which comprise water and blast furnace slag of particle size between 2,000 cm2/g and 15,000 cm2/g (200 m2/kg and 1,500 m2/kg), preferably between 4,000 cm2/g and 6,500 cm2/g (400 m2/kg and 650 m2/kg) and an activator which comprises sodium pyrophosphate to form a cementitious slurry; displacing the cement slurry to the well, and allow the cementitious slurry to set.
U.S. Pat. No. 5,447,197 teaches storable cementitious slurries made from cementing hydraulically active material, which may be stored in the liquid state. The slurry is activated when needed for cementing. After pumping the activated slurry to the interior of the well, the properties of the hardened cement are suitable for well cementing. The composition contains a set retarder aiming at maintaining the slurry in the liquid state while stored, and an activator to revert the retardation caused by the retarder.
U.S. Pat. No. 5,547,506 teaches liquid storable cementitious slurries made from hydraulically active cementitious material, a set inhibitor to allow storage of the slurry and an activator to activate the slurry.
A paper published by the Society of the Petroleum Engineers (SPE) no. 36973, of October 1996, teaches a new technology for cementing of slim wells with the aid of Liquid Cement Premix (LCP), such technology having the advantage of providing slurries having a more uniform density while dispensing with the use of expensive mixers in the field.
Conceptually, LCP is a storable cement slurry which may be indefinitely kept in the liquid state so that the set is determined as required. The slurry is a pre-mix of Portland cement or any other hydraulic material containing set inhibitors and other additives. Such system requires the use of an activator, which is added immediately before pumping the slurry to the well. The activator resumes hydration and allows that the slurry sets and develops compressive strength. The LCP properties may be adjusted with the aid of the additives used in conventional cementing operations. The slurry is compatible with all the usual cementing additives. LCP attains the usual densities. Values of compressive strength developed after around 3 hours are suitable for well cementing. The range of useful temperatures extends from ambient temperatures to 450xc2x0 F. (230xc2x0 C.).
Thus, the literature teaches cementing slurries which use water based drilling fluids and blast furnace slag as hydraulic material, the slurries being pumped to the well soon after being made. The cementing slurries of the state-of-the-art technique necessarily comprise the use of retarders/activators, this representing the presence of more reagents in the composition, besides higher cost. So, the technique is still in need of compositions and storable cementitious slurries for well cementing which may be stored at ambient temperature, dispensing with the use of inhibitors/activators, such compositions and slurries being provided for by the present invention.
The storable compositions of cementitious slurries for oil and gas wells of the present invention are based on the presence of blast furnace slag as the hydraulic material as well as on specific amounts of other components of the composition, the compositions and slurries being free of set retarders.
The storable compositions of cementitious slurries according to the present invention comprise:
Of from 200 to 500 lb of blast furnace slag/bbl of slurry (570 to 1428 kg of blast furnace slag/m3 of slurry);
Of from 0.01 to 13 weight % of activators, based on the weight of blast furnace slag;
The balance being made up of water based fluid,
The composition may still contain other usual additives for cementing and drilling fluid for oil and gas wells.
Contrary to the storable compositions of cementitious slurry of the state-of-the-art technique, the storable compositions of the present invention are formulated in the absence of any amount of set retarders.
In terms of concentration, the compositions are defined as: blast furnace slag, kg/m3, the activators, weight % based on the weight of blast furnace slag and the possible additives, weight % based on the weight of blast furnace slag or kg/m3.
Water or a water-based drilling fluid or a mixture of same constitute the continuous medium.
Another composition of cementitious slurry according to the invention contains zero percent activators at the time of the preparation, the activators being added immediately before pumping the slurry to the wellbore.
Still another composition of cementitious slurry according to the invention contains a portion of the activators at the moment it is prepared the remaining of the activators being added immediately before pumping the slurry to the wellbore.
In view of the three parameters which control the setting time of the slag-containing cementitious slurries:
physical and chemical properties (surface area, vitrification degree and chemical composition) and concentration of the blast furnace slag;
kind and concentration of chemical activators;
wellbore temperature,
The principle on which are based the compositions of the invention storable at ambient temperature in the absence of set retarders relates to the control of the blast furnace slag and the chemical activators.
It should be understood that the temperature of the wellbore where the slurries will be utilized varies within broad limits, and that such parameter cannot be controlled.
Still under another point of view, the compositions and storable slurries of the present invention may be considered as insufficiently activated, so that the set does not occur at the surface (out of the well). Activation will only occur when the compositions and cementitious slurries are chemically and thermally activated this occurring through addition of activators and by the inner temperature of the wellbore. Thus, without the need of the set retarders of the state-of-the-art, liquid slurries are obtained which are storable at ambient temperatures during prolonged periods, for example, 72 hours or more.
Thus, the present invention provides compositions and cementitious slurries storable at ambient temperature to be utilized in oil and gas wells, vertical, deviated and horizontal wells, said slurries being formulated based on blast furnace slag as hydraulic material, activators, water-based drilling fluid or water, or a mixture of same, as well as usual additives for drilling fluid and cementing slurries.
The present invention provides further compositions and cementitious slurries storable at ambient temperature where the slurry is completely free of activator, the activator being added immediately before the slurry is pumped to the wellbore.
The present invention provides still compositions and cementitious slurries storable at ambient temperature where the slurry contains a portion of the activator required for the set while another portion of the activator is added immediately before the slurry is pumped to the well.
The present invention provides further compositions and cementitious slurries storable at ambient temperature where the proper amount of the activation parameters allows that the slurry be kept in the liquid state for prolonged periods of 72 hours or more, dispensing with retarders specifically designed to retard the setting of the slurry compositions as well as activators for reversing the effect of the retarder.
Still, the present invention provides an improvement in the operation of oil and gas well cementing through the homogeneity of the slag-containing slurry, which is obtained without the risk of setting at the surface, as well as by the simplicity in the operation, this yielding less risk of operation failure and lower operation period.
The preferred modes described below together with the attached Examples illustrate the principles of the invention.
For the purposes of the present specification and claims, set retarder, or retarder, is every additive utilized in the slurry aiming at preventing the hardening or setting of the slurry before said slurry is pumped to the well annulus, and set inhibitor or inhibitor is every additive utilized in the slurry aiming at allowing the storage of same in the liquid state for prolonged periods, for example 72 hours or more.
Advantageously, the present invention provides compositions and storable slurries aiming at the well cementing which may be prepared in advance, stored, moved and taken to the site of utilization at the most convenient time, without the need of immediate use common to the state-of-the-art slurries. Such advantage is obtained exclusively by adjusting the relative amounts of the slurry constituents, dispensing with set inhibitors and activators to revert the action of the inhibitors, such as is well known for the conventional slurries.
The state-of-the-art cementing operation requires that the slurry is displaced to the wellbore as soon as the hydraulic material is mixed to the mixing water (water plus additives), in order to prevent setting in the tanks and cementing lines or still within the casing. Any of these situations constitute an operation drawback, besides damages for loss of material, working hours and waste of rig time, and even ultimately loss of the well. This way of conducting the cementing operation, by mixing hydraulic material and mixing water, followed by displacement to the wellbore causes a variation in the concentration of hydraulic material in the slurry, this in turn entraining a variation in physical properties (density, compressive strength, etc.) which possibly leads to low quality cementing to be corrected by squeezing, with the consequent increased costs.
One way to avoid the oscillation in the concentration of hydraulic material is to utilize a mixer able to prepare the entire required amount for the cementing operation in one single batch (a so-called batch-mixer). However the slurry prepared using this type of mixer increases the cost of the cementing operation of oil and gas wells.
Typically, cementitious slurries comprise cement, fresh or salted water and various other additives such as extenders, strength retrogression controllers, accelerators and retarders, fluid loss additives, dispersants and weighting agents.
In order that the cementitious slurries show the desired properties, various additives are being used. Non-limiting examples are bentonite, silica, calcium chloride, lignosulfonate and related products, boric acid, hydroxy ethyl cellulose, carboxy methyl cellulose and other cellulose derivatives, tartaric acid, citric acid and other carboxylic acids, naphthalene sulfonic acid salt, barite and hematite.
In the present specification and claims, the term xe2x80x9cwater base fluidxe2x80x9d means a fluid wherein the continuous phase is water. Non-limiting examples are fresh water, brine, sea water or other aqueous fluids isolated or combined, such as water-based drilling fluids.
Water-based drilling fluids typically comprise water and various other additives such as viscosifiers, fluid loss additives, dispersants, dissolved salts, alkaline agents, solids from the perforated formation, weighting agents, formation stabilizers, lubricants for the drilling fluid and anti-foaming agents.
In order that the drilling fluids show the desired properties, various additives have been used. Non-limiting examples are bentonite, polyacrilamide, guar gum, xanthan gum, carboxy methyl cellulose, starch, tannin compounds, lignosulfonate, polyacrylate, sodium chloride, potassium chloride, calcium chloride, sodium hydroxide, potassium hydroxide, calcium hydroxide, clays, barium sulfate or barite, iron oxide, calcium carbonate, lubricating oil, octylic alcohol and aluminum stearate
The solidification of a drilling fluid may be obtained by adding blast furnace slag as hydraulic material together with additives for the control of set time and rheological properties of the fluid, which has been slag-treated.
Blast furnace slag is a non-metallic product, which consists essentially of calcium silicates and calcium aluminosilicates, and other bases, and is produced in the melt state simultaneously with iron in a blast-furnace. Blast-furnace slag is therefore a by-product of the manufacture of iron and results from the combination of minerals from the residuum of the iron ore, the coke ashes and from the lime used as smelter. As the density of slag is lower than that of iron, the slag is poured in the melt as the upper phase at temperatures usually between 2250xc2x0 C. and 2900xc2x0 C. Such mixture is then quickly cooled aiming at obtaining glassy and powdery material, able to develop hydraulic activity.
Blast furnace slag (or slag) shows the same compounds as cement, however, at different concentrations. TABLE 1 below illustrates the typical chemical composition of blast furnace slag and Portland Cement Class G, both Brazilian made.
The hydration process of slag involves the dissolution of the anhydrous compounds, followed by the precipitation of the hydrated compounds. The agglomerating properties of the slag depend on proper activation.
Thus, slag is considered a latent hydraulic compound, since it needs activation to set. The required activation may be provided by thermal energy, chemical activators or through mechanical energy. The activation increases the solubility of slag and/or favors the precipitation of the hydrated compounds.
The mechanical activation is obtained by milling slag: the higher the surface area, the larger the dissolution of slag. The particle reduction in size increases surface area, and therefore the contact area, this increasing the hydration rates.
Thermal activation is obtained by increasing the temperature of the slag, this also increasing the solubility of the slag in solution.
Chemical activation occurs through the combination of two parameters: increase in the rate of dissolution of slag caused by an increase in pH, and anticipation of precipitation of the hydrated compounds through increase in the concentration of ions in solution or by altering the solubility of the slag compounds.
The high pH of the slag-containing solution increases the slag solubility, and consequently its hydration, since the dissolution of same is effected through a hydroxyl attack (that is, attack by OHxe2x88x92 ions), while the dissolution of the cement clinker occurs through a hydrolytic attack (that is, the action of water molecules). Hydroxyl ions may be provided either by strong bases, such as sodium hydroxide, sodium silicate of low SiO2/Na2O ratio or by weak bases, such as sodium carbonate, or sodium silicate of high SiO2/Na2O ratio.
The reactivity of the slag depends on various parameters, such as degree of vitrification, chemical and mineralogical composition and fineness.
The degree of vitrification dramatically increases reactivity: crystalline slag, obtained by slow cooling, does not hydrate. The fastest the cooling, the higher the vitrification degree of the slag, and therefore the larger the hydraulic potential of the slag. Experimental data indicate the presence of 3 to 5 weight percent of crystals in the slag in order to improve their reactivity.
The chemical composition of slag is related to the quality of the iron ore, as well as to the nature of the smelter, to the utilization of coke or charcoal as fuel, reduction activator, etc. Broadly speaking, a basic slag is more reactive than acidic ones.
Regarding to the fineness, which may be evaluated by determining the surface area, the higher the surface area, the larger the reactivity. Analogously, the higher the temperature, the greater the reactivity of a sample of slag.
In spite of the fact that several kinds of slag may be useful for the purposes of the present invention, a preferred slag is a blast furnace slag, a by-product of the manufacture of blast iron, having a vitrification degree higher than 90 weight % and surface area between 200 and 600 m2/Kg.
The rheological properties of the drilling fluid compounded with slag may be modified with the aid of conventional chemical dispersing agents for water-based drilling fluids, such as lignosulfonates, naphthalene sulfonates, phenol sulfonates, phosphates, phosphonates, sulphonated styrene-maleic anhydride, polyacrylate, polymethacrylates, mixtures of polyacrylate and polymethacrylates, acrylic acid-acrylamide copolymers, or mixtures of any of these classes provided the compounds are chemically compatible so as to mix while retaining the ability of dispersing particles in the drilling fluid.
In view of the fact that slag is a latent hydraulic material, activation is required in order to obtain a slurry of useful features. The activation of slag-containing drilling fluid usually requires the use of chemical activators besides the thermal activation. In the compositions taught in the open literature, chemical activators are used in such amounts as to effect the set in relatively short times, from a few minutes to a few hours.
As chemical activators, acids and bases may be used, such compounds increasing the pH of the liquid portion of a mixture of water-based fluid/blast furnace slag. In view of the fact that the thermal energy contributes to the overall activation energy, the kind of chemical activators and the amount of same may vary. Strong bases are usually employed at low temperatures while weak bases may be used when the temperature is higher.
The activator constituents may be a mixture of bases or bases combined to chelating, complexing or sequestering agents.
At low temperatures it is advisable to use hydroxides of alkaline and earth alkaline metals such as lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide and barium hydroxide. The more soluble hydroxides are more adequate activators for low temperatures. It is believed that the higher solubility in water at low temperatures is the main reason for the better performance of these activators at low temperatures. That is why more commonly used hydroxides at low temperatures are sodium hydroxide, potassium hydroxide, lithium hydroxide and barium hydroxide. Those hydroxides have a more pronounced effect on the setting time of the slag-containing cementitious slurry.
The usual concentrations of such hydroxides are between 0.01 and 5 weight % based on the weight of slag in the composition. Preferred concentrations are between 0.5 and 4 weight % based on the weight of slag, and the more preferred concentration is between 1 and 2 weight % based on the weight of slag of the composition of cementitious slurry.
Further, the compositions of the present invention may also contain a weaker alkaline metal base as part of the activator agent, for example, a carbonate or phosphate group-containing weaker base.
Specifically, the carbonate ion exerts a beneficial effect on the development of compressive strength and final compressive strength of the slag-containing mixture. A few anionic species may partly replace the carbonate of the activator, this causing a huge effect on the compressive strength. Alkaline metals and alkaline earth metal carbonates more commonly applied as a component of the overall activator comprise lithium carbonate, sodium carbonate, potassium carbonate, calcium carbonate, magnesium carbonate, barium carbonate, and sodium and potassium carbonate. Similarly to the alkali-containing hydroxyl groups, higher solubility provides stronger effects. More commonly used compounds, employed in the inventive compositions comprise sodium carbonate, potassium carbonate and sodium and potassium carbonate. The concentrations of those compounds used in the compositions of the invention comprise 0.01 and 8 weight % based on the weight of slag in the composition, the preferred composition being between 0.5 and 6 weight % based on the weight of slag in the composition, the optimum content being between 1.5 and 2.5 weight % based on the weight of slag present in the composition.
Therefore a typical composition of the invention comprises a total amount of activators between 0.01 weight % and 13 weight % based on the weight of slag, a strong base such as NaOH comprising between 0.01 and 5 weight % based on the weight of slag in the composition, while the weak base such as Na2CO3 is present in an amount between 0.01 and 8 weight % based on the weight of slag.
Analogously to the carbonate ion, the phosphate ion is an anionic chemical species, which may contribute to the compressive strength. However, the phosphate ion-containing compounds tend to retard the hydration of slag more strongly than does the carbonate ion. Basic phosphates such as sodium pyrophosphate, sodium hexamethaphosphate and tetrasodium polyphosphate find use in formulations for the control of setting time and aid in the development of the compressive strength. Among those, the sodium pyrophosphate shows the best potential. Typical concentrations are between 0.01% and 15 weight % based on the weight of slag, preferably between 0.5 and 8 weight % based on the weight of slag.
Citrate ion may also contribute to the compressive strength. Alkaline and alkaline earth metal salts of citric acid such as sodium citrate, calcium citrate, and potassium citrate are well known.
As for the rheological properties of the slurry, citrate and phosphate-containing compounds are advantageous when compared to carbonate or hydroxyl compounds. Citrate and phosphate-containing compounds are effectively dispersing agents for slag and clays in formulations of drilling fluids. Thus, said compounds make possible slurry compositions of lower water content or of better rheological properties.
Other components of the activator comprise a chelating, complexing or sequestering agent. Such compounds comprise the phosphate and citrate ion described hereinbefore. Other components are ethylene diamine tetracetic acid (EDTA) and their salts, phosphonic acids and their salts, glutamic acid and its salts, etc. It is preferable to use salts since the acidic forms react with added bases for the chemical activation. Soluble salts are preferred, such as sodium and potassium salts.
Concentration of activators is usually selected so as to provide maximum compressive strength for a given concentration in slag. The overall optimum concentration is referred based on the weight of slag used in the composition. This is how is selected the optimum ratio of activators to slag. The optimum weight ratio of activators to slag is reduced with the increase in temperature. Those optimum ratios may also vary with the compounds used as activators.
In the present invention, in the embodiment where the compositions are incompletely activated, the ratio of activators based on the slag is chosen so as to incompletely activate the slag so that the slag slurries be kept liquid at ambient temperature for prolonged periods, for example, 72 hours or more. Thus, this ratio is comprised, for example, for sodium hydroxide (NaOH) and sodium carbonate (Na2CO3) between 0.01% and 13 weight % based on the weight of slag present in the composition, preferably between 1.0 and 10 weight % and more preferably between 1.5% and 4.5 weight %.
As for the embodiment where the composition is kept free of the addition of activators up to immediately before the composition is pumped into the wellbore, the ratio of activators may be any, provided the amount of activators make the set after placing the slurry in the wellbore. It is well known, for example, that the excess of activators prevents the setting of the slurry.
In the embodiment of the invention where a portion of the required amount of activators is added in the amount of 0.01% to 13 weight % based on the weight of slag in the composition of slurry, and immediately before pumping the slurry to the wellbore, another portion of the activators is added, such amount may be any provided the slurry is set within the wellbore.
For the purposes of the present invention, ambient temperature means that one since which the slurry may be processed up to usual ambient temperatures, for example, 25 to 30xc2x0 C. For countries with ambient temperatures higher than 30xc2x0 C., the amount of activators should be adapted to lower limits, since there will be a certain surface activation due to higher ambient temperatures.
Contrary to the publications of the literature and in a way not cited nor suggested, which renders the present invention patentably distinguishable from all published matters, the invention does not make use of set inhibitors (retarders). On its turn, as is thoroughly explained in the referred to publications, the use of inhibitors requires, in order that the slurry composition be activated, the additional use of activators to neutralize the effect of inhibitors. It is evident that such additional chemical reagents and the consequent operations of mixture and human labor increase the costs of the cementing operation as reported in the state-of-the-art publications.
On the contrary, in one of the preferred modes of the invention, the slurry is insufficiently activated with chemical activators so that the set does not quickly occur at ambient temperature, however sufficiently activated so that the set quickly occurs within the wellbore.
In another mode, the slurry is not activated so that the set does not occur at ambient temperature, however, chemical activators are added immediately before the slurry is pumped into the wellbore, so that the slurry is quickly set at the temperature of the wellbore. This feature makes possible that the slurry may be prepared in advance, improving the quality as a result of the composition being uniform and also reducing the time of operation, since it is only necessary to displace the slurry to the wellbore.
For two formulations of the inventive slurries having optimized slag ratios and activators, the more dispersed formulation will develop as a whole better compressive strength after setting. Several complexing, sequestering or chelating agents mentioned above are good dispersing agents for slag containing drilling fluids.
Generally, in the laboratory the storable compositions of the invention may be prepared by mixing blast furnace slag, the additives in the right amount and the aqueous continuous phase The order of addition of the constituents is not critical, however it is preferred to add first the water based fluids, followed by cementing and drilling additives, activators and slag.
The mixture is prepared in an agitator with controlled rotating speed such as a Waring blender. Constituents are weighed in a scale having a precision of 0.01 g. After weighing, the water-based fluids (water based drilling fluid, fresh water, brine, etc) are added to the cup of the blender and agitated under a rotation of 4,000 rpm, during around 15 seconds. The solid constituents are added over that liquid mixture one after the other, under a rotation of 4,000 rpm, for a period of time sufficient so that all constituents are dispersed or dissolve in the slurry being prepared. During the addition of slag, at the end of the mixture, the rotation is generally increased to 12,000 rpm in order to improve and facilitate its dispersion in the slurry. Mixing time may take from a few seconds to a few minutes. Generally, additives and activators are agitated for around 50 seconds, while the slag may be agitated for a few minutes.
In the laboratory, the assessment of the properties of the slurry is effected through tests such as compressive strength, thickening time, rheology, filtrate (fluid loss), density and free water. Those tests are effected according to SPECIFICATIONS 10 of the American Petroleum Institute (API).
Before storing the slurry for assessing the storage time, the properties of the composition are measured so as to ascertain its suitability to oil and gas wells. Once the suitability of the slurry is assessed, the slurry is prepared, the rheological parameters (plastic viscosity, yield point and gels) are measured and then the slurry is stored in capped flasks in order to avoid loss of water. The rheological parameters are periodically measured at 27xc2x0 C. in order to monitor how the properties of the slurries have been modified. Whenever the slurry is too viscous and gelled, it is difficult to pump and therefore its properties are no longer suitable, the set is reached in a few hours. On stating the hardening of the slurry (set), the test is put to an end and the storage time is counted as the number of days between the preparation of the slurry and the day before the setting.
In the field, the storable compositions of the invention are prepared in a mixing tank of the rig or of the cementing unit (this is a tank provided with mechanical agitators and/or hydraulic recirculation). The constituents are weighed in a scale of 1-kg precision. After weighing, the water-based fluids (water based drilling fluid, plain water, brine, etc.) are added to the mixing tank and agitated for a few minutes. The solid constituents are added on that liquid mixture one after the other, in a period of time such that such constituents disperse or dissolve in the slurry, which is being prepared. Normally a few hours are needed to prepare a slurry.
The present invention will now be illustrated by the following examples, which should not be construed as limiting same.

Storable composition and slurries and use of same for cementing oil and gas wells


A product merchandising display unit capable of being both vertically and horizontally arranged to achieve a wide variety of different modular configurations includes plurality of substantially similar shelf members, a plurality of support members, and a plurality of full sockets and partial sockets associated with the upper and lower portions of each of the shelf members for cooperatively engaging the support members. Any number of shelf members can be vertically stackably arranged one above the other by attaching the support members to the full sockets associated with each respective shelf member. In the case where two shelf members are positioned in side-by-side relationship one adjacent the other, such adjacent shelf members can be joined along their abutting edge portions by attaching the support members to aligned pairs of the partial sockets associated with the respective shelf members. In another embodiment, sockets having split channels associated therewith are used instead of separate full and partial sockets in order to achieve the vertical and horizontal arrangements of adjacent shelf members, each split socket combining the features of a full and partial socket into a single socket.

This invention relates generally to storage and display devices for use in storing and merchandising shelved products and, more particularly, to a display unit which can be arranged to achieve almost any desired number of vertically disposed shelf members and which can likewise be horizontally arranged to achieve substantially any side-by-side configuration.
In our modern culture, the diversity and complexity of consumer goods have become extensive, and this increased diversity and complexity have created a need for more versatile display units which permit the addition and removal of shelves and the joining of adjacent display units. Known display units for storing and merchandising multiple products utilize upright support members to vertically stack shelves in spaced relationships one above the other, and a wide variety of connection mechanisms are used to attach the shelves to the upright members. Some connection mechanisms, such as those disclosed in U.S. Pat. No. 4,930,643, which is hereby fully incorporated herein by reference, permit adjacent units to be arranged and joined in a multitude of desired side-by-side modular configurations. While the connection mechanisms of U.S. Pat. No. 4,930,643 permit side-by-side arrangement of display units, these connection mechanisms require the production of unique connection members in addition to the standard elongated support members associated with a particular display unit, which connection members are complex and costly to manufacture. Further, the unique connection members are not used unless adjacent units are, in fact, joined together in a particular side-by-side configuration. Thus, the cost of manufacturing the unique connection members may be wasted if two units are not horizontally joined together. There is therefore a need for a display unit which is attachable to adjacent display units using standard support members thereby reducing cost and complexity.
There is, therefore, provided in the practice of the present invention a novel display unit which uses standard upright support members for joining both vertically spaced shelf members and horizontally arranged side-by-side shelf members. In one embodiment of the present invention, each shelf member broadly includes a floor portion, a plurality of upper full sockets, a plurality of lower full sockets, and a plurality of upper and lower partial sockets, each partial socket configured to receive a portion of one end portion of a standard elongated support member or other attachment member for attaching one shelf member to an adjacent shelf member having similar upper and lower partial sockets associated therewith. In another embodiment, the upper and lower full and partial sockets may be eliminated and each shelf member may simply include a plurality of upper and lower split sockets as will be hereinafter explained.
The partial sockets of the present invention are each configured to receive a portion of one end of an elongated support member that is normally used with the display unit, the elongated support member serving as the attachment member. Each of the partial sockets includes an outer wall and an inner wall spaced from the outer wall, the inner and outer walls forming an insert and defining a channel for receiving a portion of the elongated support member. The channel is preferably U-shaped and opens at the perimeter edge and top or bottom of the shelf member side wall. Each shelf member may also optionally include mating securement tabs and slots. The securement tabs and slots are preferably T-shaped and further secure the connection between adjacent shelf members. Alternatively, tapered keeper members may also be used to further secure adjacent shelf members. The full sockets, partial sockets, securement tabs, and securement slots are preferably all integrally formed with the shelf members.
It is further contemplated in the practice of the present invention that a plurality of the described shelf members are interconnected to form a display unit according to the teachings of the present invention. A plurality of substantially identical elongated support members are provided to connect the shelf members of discrete display units in vertically spaced arrangements and to connect adjacent shelf members in a multiplicity of side-by-side modular configurations. The support members include hollow end portions to receive the inserts of the partial sockets.
It is still further contemplated in the practice of the present invention that a plurality of the described shelf members and a plurality of the described support members are used in a method of assembling the display unit according to one embodiment of the present invention. For example, two bottom shelf members are aligned horizontally in substantially the same plane in a side-by-side relationship with the upper partial sockets on one side wall of each shelf member being positioned in an aligned and abutting relationship with each other. Elongated support members are then attached to the aligned pairs of the upper partial sockets and to the outer full sockets associated with the horizontally arranged shelf members. Two top shelf members are then attached to the upper ends of the elongated support members in a stacked vertically spaced relationship relative to the two bottom shelf members.
To attach another horizontally arranged shelf member or previously assembled display unit to the exemplary unit described above, the elongated support members are detached from the full sockets along a common edge adjacent the third display unit or other shelf member. The third display unit or other horizontally arranged shelf member is then aligned in abutting relationship with the existing unit to form pairs of upper and lower partial sockets, and the detached elongated support members are then reattached to the aligned pairs of partial sockets associated with the adjacent common edge portions of the horizontally arranged units. Additional support members are then attached to the outer full sockets of the third display unit or other horizontally arranged shelf member.

Double socket product merchandising display unit


A gamercard associated with an integrated gamer profile to identify a gamer is provided to the gamer and other PC/console users who also participate in other online gaming community activities such as game-related web sites. The gamercard is also provided to the user from the central database through a gamercard server by a user providing a single URL from any device connected to the web. The URL is uniform for each gamer's gamercard, except for the part of the URL that includes the name associated with the particular gamer.

In online gaming a multimedia console gamer has a garner profile that was unique to the console they play on. When they play games on the console, the user profile information for those games is stored in locally on a memory unit or hard drive. When that same user surfs the web and specifically, participates in any sort of forum on the web, they can not view, access, or contribute to that locally stored profile. There is no ability for users to view, access, and/or contribute to their console gamer profile using the game-related web sites or other servers than the online gaming service.
Also, garners who first participate in game-related forums on the internet and the web before participating in online gaming, have no way to easily connect their game-related identity and profile on the internet and the web to the online gaming identity and profile created once they choose to participate in online gaming. Additionally, there is no ability for garners to integrate into one identity the profile information particular to that created during the online gaming participation (such as game achievements, for example) to other user profile information particular to that created when participating in the game-related forums within web sites (such as reputation ratings, for example).
Furthermore, the console game-related identity of a user, which may include a subset of the gamer profile information selected for public viewing, is not available to the user or other users outside the online gaming service. It is not able to be moved and embedded easily into the user's or other user's web sites, PC desktops, or other devices such as PDA's or cellular phones, nor be brought up in a web browser or other networked device directly by typing a single network address such as a uniform resource locator (URL).
In view of the foregoing, there is a need for a system that overcomes the drawbacks of the prior art.

Viewing a gamer card across multiple devices and networks


The present invention relates to a process of treating contaminated water containing microorganisms comprising feeding a contaminated water stream at a volumetric flow of about 1 to about 1000 m3/h through an electrolyser zone, said water stream having a conductivity from about 0.0001 to about 100 S/m, electrolysing said water stream in said electrolyser zone defined by at least one electrode pair enabling treatment of microorganisms, said at least one electrode pair comprising an anode and a cathode without separator means, said water stream being guided substantially perpendicularly through said at least one anode and cathode while imposing a voltage across said anode and cathode and supplying a direct current to said anode and cathode, withdrawing from the electrolyser zone a treated water stream. The invention also relates to an electrolytic cell in which said process can be performed, and to the use of the electrolytic cell.

Treatment of waste water containing microorganisms has been performed for a fairly long period of time. However, treatment processes based on electrolysis have hitherto not been completely problem-free. Inefficient processes as well as expensive equipment or high energy consumption have previously prevented improved handling of microorganisms occurring in e.g. waste water, cooling water, ballast water, and recirculated washing water. U.S. Pat. No. 5,419,824 discloses an electrolytic cell for destroying contaminants. However, this process is very expensive and inefficient for applications where large volumes of water are treated due to extensive pressure drop, low flow rates, and low current efficiency.
In WO 02/26635, it has been further tried out embodiments for reducing contaminants and microorganisms in which alternating current is supplied to a cell. This has, however, not always been seen to be a successful way of performing the chemical reactions in the cell.
It has been further seen in the prior art that cleaning systems involving reduction of contaminants often have been provided with a reactor tank arranged to the pipings through which the medium to be cleaned passes. This configuration, however, often results in pressure drops and lower throughput of the medium to be cleaned. The retention time may also be prolonged which is not always satisfying, particularly if large volumes of contaminated water needs rapid treatment.
The present invention intends to provide an efficient process and a cell solving the problems of the prior art. A further object of the present invention is to provide an improved control of the hydrogen and chlorine formation in the electrolytic cell.


A method comprising the following steps: preparing in a vacuum a dry form (18) of an active principle, as well as a liquid (22), and drawing this liquid into the dry form, by the action of the vacuum to obtain an injectable preparation. The device comprises a gastight syringe (19) to condition under vacuum the dry form, a reservoir (12) containing the liquid (22) and a cap (29) forming a connector between the syringe and the liquid reservoir, the injection needle (25) of the syringe being driven into the septum (24) of the cap (29). The invention enables a preparation which is directly injectable by an automatic rehydration step to be obtained; indeed, after activation, the extemporaneous preparation is automatic since the device elements move by themselves under the action of the liquid which is drawn by suction into the volume under vacuum containing the solid formulation (18).

This is the 35 USC 371 national stage of international application PCT/FR97/00989 filed on Jun. 4, 1997, which designated the United States of America.
The present invention provides a process for preparing an injectable pharmaceutical preparation, a device for implementing said process and the product obtained by implementing the process by means of the device.
It is known that injectable forms are immediately bioavailable and constitute a potential passive mode of administration for the patient and an ideal treatment in urgent cases.
Another important reason for the development of parenteral forms is the use of active principles (AP) which are degraded and/or not significantly absorbed by the oral route.
Of all these AP which, for various reasons, require an injectable form, many of them are unstable in aqueous media, whether in solution, suspension or dispersion.
In order to avoid hydrolysis and all the physico-chemical problems associated with a liquid presentation (precipitation, aggregation, adsorption, crystallisation), a presentation is often used in which the AP is preserved in a solid, dried or freeze-dried form.
The preparation of the liquid form required for injection then takes place extemporaneously, just prior to injection.
This preparation consists in hydrating the solid form with the liquid medium for solubilisation or suspension of the AP.
Traditionally, this operation is carried out in a sealed bottle which contains the solid form. The liquid is introduced into the bottle by a syringe, the needle of which is capable of piercing a stopper-septum.
The liquid form is then recovered in the syringe so that it can be injected.
The time required for this delicate operation and the risks of contamination it involves led experts in medical technology to devise devices for making extemporaneous preparation simpler and more reliable, and for using the fewest possible components.
Along such lines, the patents EP-A-0 664 136, DAIKYO SEIKO, EP-0 599 649 PHARMACIA, WO-95 11051 disclose a bicompartmental or xe2x80x9cby-passxe2x80x9d syringe which combines in the same syringe the liquid medium and the solid form which will be directly rehydrated in the syringe before injection.
Similarly, certain producers propose devices which combine the bottle with the syringe and control the satisfactory execution of the preparation (French patents DEBIOTECH 2 705 898, 2 715 311, 2 717 086).
Certain faults in the traditional systems are not, however, solved by said new devices, which pose problems of loss of preparation in their dead volumes, which do not render rehydration automatic and static but keep it manual and dynamic, that is, the flow of liquid and the transfers after hydration displace the solid form and, in particular, the AP. The injectable form does not, therefore, necessarily have the same distribution or homogeneity as the dry form. This constitutes a problem, particularly in the case of suspensions.
The fact that preparation is dynamic and carried out manually may lead to important differences depending on the operator, the speed with which he acts, the manner in which he loads the liquid and controls the evacuation of the air. Finally, the force with which the solid AP is hydrated is likely to lead to a relatively substantial emulsion of microbubbles of air.
The time allowed for solubilisation or suspension and agitation of the liquid medium determines the homogeneity of the preparation.
In the case of suspensions, poor homogeneity or the onset of sedimentation may lead to dose and administration problems.
The object of the invention is to propose a process for overcoming these various disadvantages.
According to the invention, the process for preparing an injectable preparation is characterised in that a dry form of an active principle under vacuum and a liquid are prepared, and said liquid is introduced into the dry form by suction by virtue of the action of the vacuum in order to form the said injectable preparation.
The process of preparation and packing under vacuum according to the invention avoids the above-mentioned problems (dead volume, manual activation, injectability) and at the same time the problems of injected liquid formulation (homogeneity, degassing).
According to a characteristic of the process, the dry form under vacuum occupies the same volume as the final form obtained after automatic hydration by a corresponding, exactly pre-determined volume of liquid.
According to an embodiment of the process of the invention, a layer of excipient is added to the dry form, said layer being used subsequent to the injectable preparation as a liquid piston in order to push the other layers and to reduce the losses of active principle during injection.
According to another embodiment of the process of the invention, the dry form is packed in a syringe fixed to an automatic rehydration device; in order to prepare the dry form, a liquid containing the active principle is frozen, a specific quantity of excipient solution is added to the surface of the frozen liquid, this excipient solution is frozen, the whole unit is freeze-dried so as to obtain, between the piston of the syringe and the solid of active principle under vacuum, a volume of freeze-dried product containing only the excipient which, after automatic rehydration and movement of the piston in order to empty the syringe, occupies a dead volume at the bottom of the syringe and of the injection needle at the end of injection.
This process of preparation and packing leads to automatic rehydration: it is sufficient for the user to activate the device for the liquid to restore the solid form to the state it was in prior to drying or freeze-drying. Activation of the device consists in bringing into contact the liquid volume and the solid volume under vacuum. After activation, extemporaneous preparation is automatic, that is, the components of the device move solely under the action of the liquid which is drawn by suction by the vacuum under which the solid formulation is placed.
This property of vacuum packing is independent of the operator, and hydration leads to an immediate return to the situation of the liquid form prior to drying or freeze-drying.
The solid form and active principle remain static during this hydration, that is, they are not displaced by the liquid.
This immediate preparation is thus directly injectable without the need to agitate it, transfer it or expel the air before injection.
This process of preparation and packing may use certain devices or containers currently available, provided that they ensure that the form under vacuum is kept under vacuum until rehydration. The component(s) of the device must allow this rehydration whilst avoiding contact with the ambient air.
This feature also leads to certain specific devices or components for this process of preparation and packing. These devices and components will be described below.
The techniques for vacuum packing the solid form in the device and the packaging are derived from existing techniques (blood sampling tube, packing under a plastic film). This vacuum packing of the solid form and of the AP is, moreover, capable of replacing inert gas blanketing (nitrogen) and improving the stability of the preparation particularly at high temperatures (thermal insulation) and the compatibility with the container (contact insulation).
The above-mentioned advantages of the process and of the devices of the invention, which will be explained below, are particularly important for certain preparations:
For a solid, readily solubilised preparation, the advantage is that of obtaining immediately a degassed liquid preparation without air bubbles.
For a solid preparation which is more difficult to solubilise, either due to its viscosity or due to the time required for solution, the formulation under vacuum avoids the emulsion of air in the liquid, simplifies and accelerates solubilisation.
For a suspension and, more especially, for a sustained-release suspension of microspheres (Decapeptyl 3.75 B.1), the formulation under vacuum avoids the problems of dehomogenisation and the risks of precipitation, hence blocking off whilst reducing the time required for reconstitution.
The pharmaceutical preparation under vacuum and the preloaded device make it possible to reduce considerably the dead volume and hence the losses of active principle.
Finally, for a dispersion and more particularly for semi-solid forms, the very high viscosity of the hydrated form makes it practically indispensable to use a process of preparation and packing under vacuum for the dry form.
The non-liquid or semi-solid aqueous form obtained after hydration under vacuum is, moreover, likely to have salting out properties which are different to and better than those of a form hydrated in air. The fact of not having trapped air in the dispersion makes it possible to reduce the volume for the same quantity (which improves salting out) and avoids rupture of the in situ depot structure which may also modify salting out.
The process, packing and devices are described here for aqueous liquid forms. It goes without saying that the whole of the invention applies with the same advantages to liquid forms (solution, suspension or dispersion) which are reconstituted from a mixture of water-organic solvent, from an organic solvent, or from other liquids such as injectable oils.
The speed of the process of preparation and its realisation in a hermetic packing compensates for the viscosity or the risks of evaporation of certain liquids.
The device for implementing the process according to the invention is characterised in that it comprises means of vacuum packing a dry form, means of packing an extemporaneous rehydration liquid, and of connection between these means in order to add, by suction, the liquid to the dry form.
According to a preferred embodiment, the means of vacuum packing the dry form are a gastight syringe and the means of packing liquid are a reservoir containing a piston.
The syringe is preloaded with the solid form under vacuum, the packing of which allows immediate injection after hydration without agitation, and avoiding the transfer of the solution or suspension through a needle from the preparation reservoir of the liquid to the syringe.
Another advantage of the vacuum-packed devices is that it is thus possible to reduce the volumes of the reservoirs of the liquid and solid whilst increasing the precision of the volume injected.
In fact, the absence of air makes it possible to fill completely the compartment containing the solid. The volume contained in the liquid compartment may be calculated exactly in order to occupy the volume left empty in the preparation plus losses of the device. But this volume may also be in excess because it is the volume of the empty space in the solid that will determine exactly the quantity of liquid required for rehydration.
The device containing the rehydration liquid is advantageously contained in an leakproof reservoir, the volume of which may fall freely as the liquid is transferred to the reservoir of the solid form under vacuum.
This may be obtained easily, in particular, with a cartridge or with a pre-filled syringe, the piston of which moves with the movement of the liquid.
The reservoir may also be composed of a pre-filled flexible plastic bag, the flexible walls of which will follow the movement of the liquid.
The connecting element of the liquid and the vacuum shielded from the ambient air may be composed of a septum, a gate, valve or tap.
One of the characteristics of the method and of the devices is to reduce the dead volumes. This is achieved not only by reducing the volume of the connecting components (liquid-vacuum) or injection components (needle-syringe) but also by virtue of the static rehydration process which makes it possible to occupy the dead volumes with liquid without active principle, and hence without loss of injection.
Thus, the connecting component and/or the needle may be loaded with liquid without active principle in order to eliminate losses.
Moreover, it is possible, by virtue of the same static process, to provide the xe2x80x9cliquid pistonxe2x80x9d without active principle mentioned above, which will occupy the dead volumes of the injection syringe and of the needle after administration, thus making it possible to reduce even further the losses of active principle. This is simply obtained by adding, after freezing the liquid formulation containing the active principle, a calculated volume of a solution of excipient such as mannitol, which will be frozen and freeze-dried at the same time as the formulation. By virtue of static and rapid rehydration, the two liquids, once re-formed, will hardly mix at all and the liquid without active principle will be able to push all the liquid with active principle out of the syringe and the needle (like a xe2x80x9cliquid pistonxe2x80x9d), which will avoid losses.
In all cases (solution, suspension or dispersion), once the solid form has dried or freeze-dried, if the syringe is closed on the injection side by the connecting component, the needle or a septum, the piston is placed under vacuum with or without a blocking system, for example, inside the freeze-dryer. If the syringe is open, it can be vacuum-packed at the time of packaging under plastic film.
Even if the packing of the closed syringe is carried out beforehand under vacuum, it will be best then to pack this syringe under vacuum in such a way that the packaging, and not the syringe, ensures air-tightness during storage. This constitutes a double safety mechanism and also facilitates monitoring of the integrity of the packaging prior to use (opening).
The product or final form obtained after hydration of the solid may take one of the three forms below:
1) Solutions
The active principle combined, for example, with mannitol, is solubilised in water for injectable preparation; the solution is distributed by volume inside the syringes; the syringes are frozen and freeze-dried according to a conventional process and the solid freeze-dried product is vacuum-packed with the syringe, whether or not the syringe has been fixed beforehand to the other components of the extemporaneous rehydration device.
2) Suspensions
In the case of sustained-release microspheres, for example, the dose of microspheres is weighed into the syringe. The volume of dispersion liquid is added. The microspheres are then dispersed mechanically in the liquid. Ultrasonics are preferably used for this dispersion operation. The dispersion is then frozen rapidly, preferably in liquid nitrogen to obtain a homogeneous dispersion of the microspheres in the frozen liquid. The liquid contains the matrix of the freeze-dried product, for example, mannitol. Freeze-drying is carried out to obtain a solid in which the microspheres are suspended by the matrix in the ideal state of homogeneous dispersion of the liquid.
This solid, whether or not it is combined with the components of the automatic device for extemporaneous rehydration, is then vacuum-packed.
3) Dispersion
In the case of a semi-solid implant, for example, the semi-solid Autogel BIM 23014C, the active principle is weighed out inside a gastight metered-dose syringe.
The product obtained by implementing the process and device according to the invention comprises a dry form for parenteral administration and vacuum-packed inside an injection device also containing a liquid volume, ready to be mixed by suction with the dry form in order to reconstitute the injectable preparation.
The dry form may be a freeze-dried form or a powder obtained after removal of a solvent.

Method for preparing an injectable preparation and device for implementing same

Societe de Conseils de Recherches et D""Applications Scientifiques SCRAS


A system and process for producing tissue webs is disclosed. The tissue webs are formed from an aqueous suspension of fibers and dried using a through-air dryer. During formation of the web, the web is transferred from a transfer fabric to a throughdrying fabric and then conveyed around a drying cylinder of a through-air dryer. In accordance with the present invention, a pressurized roll emits a gaseous stream through a pressurized zone that pushes and transfers a wet web from a transfer fabric to the throughdrying fabric. The amount of pressure used during the transfer can vary depending upon the particular application and may be used to control the bulk of the web. By using a pressurized transfer roll, the amount the throughdrying fabric is wrapped around the drying cylinder of the through-air dryer can be maximized for increasing the efficiency of the system and the process.

In the manufacture of high-bulk tissue products, such as facial tissue, bath tissue, paper towels, and the like, it is common to use one or more throughdryers for partially drying the web or to bring the tissue web to a final dryness or near-final dryness. Generally speaking, throughdryers typically include a rotating cylinder having an upper deck that supports a drying fabric which, in turn, supports the web being dried. In one embodiment, heated air is provided by a hood above the drying cylinder and is passed through the web while the web is supported by the drying fabric. In an alternative embodiment, heated air is fed to the drying cylinder, passed through a web traveling around the drying cylinder, and is then fed to and collected in a hood.
When incorporated into a papermaking system, throughdryers offer many and various benefits and advantages. For example, throughdryers are capable of drying tissue webs without compressing the webs. Thus, moisture is removed from the webs, without the webs losing a substantial amount of bulk or caliper. In fact, throughdryers, in some applications, may even serve to increase the bulk of a web. Throughdryers are also known to contribute to various other important properties and characteristics of the webs.
The use of throughdryers, however, can be expensive. For instance, in addition to the capital costs associated with the equipment, throughdryers have relatively high-energy requirements. Therefore, a need currently exists for a system and process for reducing the energy costs associated with throughdryers, while still retaining all the benefits and advantages to using throughdryers.

System and process for throughdrying tissue products