Showing papers on "Precipitated silica published in 1999"

Bonding between precipitated silica and epoxidized natural rubber in the presence of silane coupling agent

Abstract: Results of Monsanto rheometic studies and measurements of physical properties reveal that precipitated silica interacts chemically with epoxidized natural rubber (ENR) during high temperature (180°C) molding and the extent of chemical interaction increases in the presence of silane coupling agent, namely N-3(N-vinyl benzyl amino) ethyl-γ-amino propyl trimethoxy silane monohydrogen chloride. Fourier transform infrared spectroscopic studies show that silica is bonded to ENR through formation of Si—O—C bond, whereas in the presence of silane coupling agent, silica is bonded to the coupling agent through Si—O—Si bond, and ENR is bonded to the coupling agent through C—N—C bond formation. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 389–398, 1999

Effects of fillers on mechanical properties of a water‐swellable rubber

Abstract: The mechanical properties of the water-swellable rubber prepared by blending polychloroprene with precipitated silica, crosslinked sodium polyacrylate, polyethylene oxide, and vulcanizing agents—such as stress at break, strain at break, modulus, energy at break, and hardness—were studied before and after swelling with water. The results showed that the addition of the reinforcing filler (precipitated silica) increased the mechanical properties, while adding crosslinked sodium polyacrylate decreased the mechanical properties, although it could improve water-absorbent properties of the water-swellable rubber. If some polyethylene oxide was included in the rubber formulation, the water-absorbent properties and the mechanical properties of the rubber both increased; but, with the increase of more polyethylene oxide, the mechanical properties decreased. Wide-angle X-ray diffracting analysis was conducted to study the crystalline behavior of the rubber, which showed that the crystallinity of the vulcanized polychloroprene increased first and then decreased with an increase in the amount of polyethylene oxide. The crosslink density of the rubber was calculated by the Flory–Rehner equation. The mechanical strength of the rubber significantly decreased after swelling with water, compared with that before swelling with water. The morphology of blends was shown by scanning electron microscopy graphs. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 577–584, 1999

Hydrophobic precipitated silica

Abstract: Hydrophobic precipitated silica having the physical/chemical parameters: Drying loass [%] 2.0-10 DIN ISO 787/2 Ignition loss [%] 2-25 DIN ISO 3262/11 Methanol wettability [%] 20-80 titrated Carbon content [%] 1-30 — is produced by mixing a precipitated silica suspension with a silane emulsion and drying it. The hydrophobic precipitated silica may be used for the production of defoamers and in papermaking.

Liquid compositions which reversibly viscosify or gel under the effect of shear

Abstract: The present invention provides a water-based fluid, in particular for drilling, completion or for any other intervention in a well such as a hydrocarbon well, in which the viscosity is controlled by a system constituted by precipitated silica nanoparticles (A) associated with a water-soluble copolymer (B) comprising one or more water-soluble co-monomers (I) having little or no affinity for silica and one or more co-monomers (II) which adsorb onto the silica. The invention is of particular application to the secondary recovery of hydrocarbons.

Precipitated silicic acid

Abstract: Precipitated silica having the following parameters: BET surface area 80-180 m 2 /g CTAB surface area 80-139 m 2 /g BET/CTAB ratio 1.0-1.6 Sears No. (consumption of 5-25 ml 0.1 N NaOH) DBP No. 200-300 ml/100 g Al 2 O 3 content <5% wk coefficient <3.4 Degraded particles <1.0 μm Non-degradable particles 1.0-100 μm is prepared by reacting alkali silicate with mineral acids and aluminum sulfate solution at temperatures of 60-95° C. at a pH of 7.0-10.0 while stirring constantly, wherein the reaction is continued to a solids concentration of 40-110 g/l, the pH is adjusted to a value between 3 and 5, and the precipitated silica is filtered off, washed and then dried, and optionally ground or granulated.

Rubber composition containing silica having first and second aggregates each containing different particle sizes

Abstract: The present application relates to a rubber composition containing a precipitated silica filler having first and second aggregates. The first aggregates are from 10 to 90 weight percent of the overall weight of the silica having first and second aggregates. The second aggregates range from 90 to 10 weight percent of the overall weight of the silica having first and second aggregates. The first aggregates consist essentially of particles ranging in size of from 5 to 15 nanometers in diameter. The second aggregates consist essentially of particles ranging in size of from 17 to 30 nanometers in diameter. The pore size distribution of the silica, as measured by mercury porosimetry is monomodal.

Tire with epdm-based component

Abstract: The invention relates to a tire having a sidewall component of an EPDM-based rubber composition prepared with specified precipitated silica reinforcement and an organosilane disulfide material. In one aspect, such rubber composition may be exclusive of carbon black and may thereby be of color other than black.

Precipitated silica granules

Abstract: Low-dusting precipitated silica granules have the following dusting parameters (measured with a Cassella dust meter): maximum ≤ 5.0 wt.%; dust number (maximum plus value after 30 seconds) ≤ 10.0 wt.%; settling time to 5% dust ≤ 5 seconds; settling time to 2% dust ≤ 50 seconds. An Independent claim is also included for the production of granules as above by adjusting a suspension of precipitated silica to a pH of 2-3.9 and spray drying the suspension.

Dispersible free flowing particulate silica composition

Abstract: Described is a free flowing particulate composition comprising, in combination, particulate amorphous precipitated silica, e.g., in the form of granules, hydrocarbon process oil, e.g., an aromatic process oil, and organic carboxylic acid having from 2 to 30 carbon atoms, e.g., stearic acid. The hydrocarbon process oil and organic carboxylic acid are sorbed on the silica and are present in amounts sufficient to measurably improve the dispersibility of the particulate amorphous precipitated silica into an elastomer as measured by percent white area. Optionally, an organosilane coupling agent may also be present in said composition. The free flowing particulate composition of the present invention is useful in reinforcing elastomers, e.g., rubbers used in vehicle tires and the soles of athletic foot wear.

Alumina doped silica prepared pyrogenically using an aerosol

Abstract: Pyrogenic silica doped with alumina by means of aerosol is based on pyrogenic silica produced by flame oxidation or flame hydrolysis and contains 1 x 10 to 20 wt.% dopant. Pyrogenic silica doped with alumina by means of aerosol is based on pyrogenic silica produced by flame oxidation or flame hydrolysis and contains 1 x 10 to 20 wt.% dopant. The amount of dopant (preferably) is in the 1-10,000 ppm range and the dopant is aluminum (Al) salt(s), a suspension of an Al compound and/or Al. The doped oxide has a BET surface area of 5-600 m /g. Independent claims are also included for (a) the production of the doped pyrogenic silica; (b) mixtures of 0.01-100% of this product and other pyrogenic or precipitated silica, bentonite and/or other fillers normally used in the paper industry.

Fine spherical silica powder and its production and use

Abstract: PROBLEM TO BE SOLVED: To obtain fine spherical silica powder which has a specific average particle diameter, a specified specific surface area, a specified silanol group concentration, improved dispersibility and improved chargeability, by spraying siliceous raw material powder into a high temperature flame, maintaining a dew point to a specific value from the body of a furnace to a collector, and classifying the obtained spherical silica fine powder. SOLUTION: This fine spherical silica powder having an average particle diameter of 0.10 to 1.0 μm, a specific surface area of 5 to 40 m2/g and a silanol group concentration of 0.5 to 5.0 groups/mm2 is obtained by supplying a flammable gas such as propane and a supporting gas such as oxygen into a spherical burner 2 in a vertical furnace 4 to generate a high temperature flame 3, spraying a siliceous raw material powder, such as natural silica powder, quartz powder or precipitated silica powder, into the flame by the use of a carrier gas to melt the siliceous raw material powder, guiding the obtained spherical silica fine powder from a water-cooled exhaustion connection pipe 5 to a cyclone 6 to collect and classify the spherical silica fine powder by the operation of a suction blower 8, and further collecting the fine powder with a bag filter 7. Therein, a furnace top outer air control valve 12 and a furnace bottom outer air control valve 13 are adjusted to maintain the dew point of the gas to 30 to 75°C from the body of the furnace 4 to the collectors 6, 7. COPYRIGHT: (C)2001,JPO

Properties of precipitated silicas, modified with 3‐amino‐propyltriethoxysilane as semi‐finished product for preparation of pigments

Abstract: Surface of precipitated silica was modified with 3‐aminopropyltriethoxysilane. The optimum solvent was selected, in which the silane coupling agent was deposited on silica surface. Basic physicochemical properties of the modified silica were estimated. Methods of evaluating silica surface modification extent were presented, taking advantage first of all of its altered hydrophilicity and of differences in condensation extent of surface silanol groups. The modified silica was used as adsorbent capable of trapping water soluble organic amines.

Composition containing calcium carbonate and tire having tread

Abstract: PROBLEM TO BE SOLVED: To obtain a rubber composition for a tire tread containing a carbon black and/or silica reinforcing material in a reduced addition level, and having a large impact resilience value at a high temperature while substantially keeping an acceptable friction resistant properties and an acceptable static friction characteristics of the tire tread. SOLUTION: This rubber composition comprises (A) 100 pts.wt. elastomer of at least one kind of a dienic rubber or a combination of the dienic rubber with an epoxydized dienic rubber, (B) 15-45 phr fine-grain reinforcing material selected from carbon black and/or precipitated silica, (C) 5-50 phr fine-grain calcium carbonate and (D) at least one kind of modifiers selected from dithiodipropionic acid, nicotinic acid amide and bis-3-(trialkoxysilylalkyl) polysulfide containing a polysulfide bridge having average 2.1-4 sulfur atoms therein and an alkyl group having 2-4 carbon atoms. The rubber composition is especially suitable for the tire tread. COPYRIGHT: (C)1999,JPO

Tear Strengths of Poly(Dimethylsiloxane) Networks Reinforced with in-Situ Precipitated Silica

Abstract: The tear strengths of in-situ filled poly(dimethylsiloxane) (PDMS) networks were investigated using “trouser-tear” tests. The filled PDMS networks were prepared by the simultaneous curing and in-situ precipitation technique, the silica reinforcing phase being obtained by the hydrolysis and condensation of tetraethoxysilane present in excess of that required for the chain end-linking process. Transmission electron micrographs showed well-dispersed and unagglomerated silica particles, and thermogravimetric analysis indicated that the silica particles gave some improvements in thermal stability. In the tearing tests, “stick-slip” tearing was observed at higher rates, especially for the filled networks. The tear strengths were found to increase with increase in the amount of silica incorporated, with the largest increases occurring at the low silica contents.

Effect of Fillers on the Properties of Prevulcanized Natural Rubber Latex Film

Abstract: Precipitated silica, china clay and whiting were incorporated in NR latex compounds up to 20 phr and prevulcanized at 70°C for 2 h. Cast films were prepared and the effect of leaching in water on mechanical properties evaluated. Rubber-filler interaction, ageing resistance, stress relaxation and morphology of the leached films were also studied. Presence of precipitated silica, china clay and whiting decreased tensile strength and elongation at break but increased the modulus of the prevulcanized latex film. Leaching of the films improved the properties. The presence of precipitated silica and china clay improved the tear strength of the films. Ageing resistance was also increased by the presence, of up to 10 phr, of precipitated silica. The rate of stress relaxation was slightly higher for the film containing precipitated silica followed by those containing china clay and whiting. Morphology of the films revealed uniform distribution of fillers in the rubber matrix.

Elastomeric matrix reinforced with precipitated silicas

Abstract: A mechanically strong, vulcanized elastomeric matrix having an effective amount of a reinforcing filler material homogeneously dispersed and distributed therethrough, the reinforcing filler material comprising finely divided precipitated silica particulates and the precipitated silica particulates deriving from a powder having a CTAB specific surface ranging from 100 to 140 m 2 /g, a median diameter φ 50 , after ultrasonic disintegration, less than 2.8 μm, exhibiting an ultrasonic disintegration factor F D greater than 3 ml, having a BET specific surface ranging from 100 to 200 m 2 /g, having a mean particle size greater than 15 μm, a packing density in the tamped state of at least 0.17, and a DOP oil uptake ranging from 150 to 400 ml/100 g.

Precipitated silica and its production

Abstract: PROBLEM TO BE SOLVED: To produce precipitated silica manifesting a reinforcing effect with good balance, when it is filled in elastomer or resin. SOLUTION: In the precipitated silica, a specific surface area measured by cetyltrimethylammonium bromide(CTAB) adsorption is 180-270 m /g, and on a fine pore distribution measured by mercury penetration method, a proportion of a volume of fine pores having >=50 Å and =70 Å and =100 Åand <=150 Å fine pore diameter is 10-30%.

Silica microbeads having sensory properties in the mouth, their method of production and toothpaste products containing same

Abstract: The invention relates to precipitated silica microbeads having sensory properties in the mouth and a specific surface CTAB of at least 100 m2/g, an oil absorption DOP of at least 200 ml/g, a mean particle diameter of between 50 and 600 νm, at the surface between 0.5 and 2 parts by weight (expressed as zinc metal) of a zinc derivative with a degree of oxidation of 2 per 100 parts by weight of silica, a pH of between 7 and 9, and possibly between 0.2 and 5 parts by weight of a white pigment for 100 parts by weight of silica. The invention also relates to a method for producing said microbeads by precipitation, treatment of the silica slurry with a soluble zinc compound, mechanical thinning of the cake resulting from the separation of the treated silica slurry, and drying by atomisation. The invention further relates to their use in toothpaste preparations as sensory agents acting in the mouth.

Rubber composition containing silica having the first and the second aggregates having different particle sizes from each other

Abstract: PROBLEM TO BE SOLVED: To provide a rubber composition that is useful as tires. SOLUTION: This rubber composition is characterized by including a precipitated silica including the first aggregate and the second aggregate. The first aggregate amounts to 10-90 wt.% based on the whole weight of the silica including the first and second aggregates, while the second aggregate amounts to 90-10 wt.%. The first aggregate substantially comprises particles of 5-15 nm diameter, while the second one has 17-30 nm particle sizes. The pore size distribution is in the single mode according to the mercury porosimetry. COPYRIGHT: (C)1999,JPO

Precipitated silica particulates with improved dispersability

Abstract: The present invention provides a particulate dispersible silica, comprising on its surface an adsorbed material such that the volume of pores of diameter smaller than 175 A is preferentially reduced, and a process for preparing such silica.

Process for the precipitated silica new precipitated silicas containing zinc and their use for the reinforcement of elastomers

Abstract: The invention relates to a new process for the preparation of precipitated silica which has a good dispersibility and very satisfactory reinforcing properties. It also relates to new precipitated silicas which are in the form of powder, of substantially spherical beads or of granules, these silicas being characterized by the fact that they have a CTAB specific surface of between 90 and 250 m 2 /g, a BET specific surface of between 90 and 250 m 2 /g, a DOP oil uptake lower than 300 ml/100 g, a zinc content of between 1 and 5% by weight, and by the fact that the number N of stearic acid molecules consumed per nm 2 of silica surface, when stearic acid is reacted with this silica in xylene for 2 hours at 120° C., is at least 1. The invention also relates to the use of the said silicas as reinforcing fillers for elastomers, especially for improving their rheological properties.

Asymmetric siloxy compound

Abstract: PROBLEM TO BE SOLVED: To provide a sulfur-containing organic silicon compound useful as a reactive coupling agent between rubber and a filter material of silica, in a rubber composition filled with silica. SOLUTION: This compound is expressed by the formula [wherein, R 1 to R 3 are each a 1-8C alkoxy; R 4 is a 1-15C alkylene, a 6-10C arylene or an arylene substituted with an alkyl; (n) is an integer of 1-8]. When (A) 100 pts.wt. conjugated diene-based elastomer incorporated with 10-250 phr finely divided particle-like precipitated silica and (B) 0.05-15 phr of the asymmetric siloxy compound are mixed, the siloxy compound acts as a silica coupler and, after curing, produces cured rubber having improved physical properties and useful as tire tread. COPYRIGHT: (C)1999,JPO

Silica-reinforced rubber composition and tire with tread prepared therefrom

Abstract: PROBLEM TO BE SOLVED: To obtain a rubber compsn. reduced in vol. resistivity by compounding a diene elastomer, reinforcing fillers comprising precipitated silica and a carbon black, and a composite material comprising a rubber compounding ingredient or a silica coupling agent and a carbon black. SOLUTION: This compsn. contains 100 phr diene elastomer (e.g. cis-1,4- polyisoprene), 35-110 phr reinforcing fillers comprising 25-100 phr precipitated silica and 10-25 phr carbon black, and 2-20 phr composite material comprising a liq. or solid rubber compounding ingredient (e.g. an antidecomposition agent, a vulcanization accelerator, or an activator) or a liq. silica coupling agent and a carbon black. Pref., the composite material is obtd. by preforming a sulfur-contg. organosilicon compd. [e.g. 3,3'-bis(trimethoxysilylpropyl)disulfide]- based silica coupling agent and a carbon black having a DBP absorption of 280-600 cm3/100 g and a BET value of 550-1,200 m2/g. COPYRIGHT: (C)2000,JPO

Hydrophobe precipitated silicic acid

Abstract: Hydrophobic precipitated silica (I) with a drying loss of 2.0-10% (DIN ISO 787/2), calcination loss of 2-25% (DIN ISO 3262/11), methanol wettability of 20-80% (titrated); and carbon content of 1-30% is claimed. An Independent claim is also included for the preparation of (I).

Improvement of hardening adhesion of pre-cured rubber compound with uncured rubber compound

Abstract: PROBLEM TO BE SOLVED: To improve hardening adhesion between a pre-hardened rubber compound and an unhardened rubber compound by using said pre-hardened rubber compound which includes a natural rubber or an emulsion-polymerized styrene- butadiene rubber, a precipitated silica, a hardening accelerator, a sulfur and a zinc oxide but does not include a fatty acid other than a fatty acid from the rubber. SOLUTION: A pre-hardened rubber compound comprises six components, that is, 40-100wt.pt., per 100 pt.wt. of total rubber, of a natural rubber and/or an emulsion-polymerized styrene-butadiene rubber which may contain 0.5-3 phr of a fatty acid included in the natural rubber or coming from the emulsion polymerization process of the styrene-butadiene rubber, 3-80 phr of a precipitated silica, 0.8-3.5 phr of a hardening accelerator, 1.0-3.5 phr of a sulfur (a weight ratio of the hardening accelerator to sulfur = 0.5:1 to 1-3.5:1), 1-10 phr of a zinc oxide and 0.5-3 phr of any fatty acid other than a fatty acid existing in the rubber component.

Filled slurry for wrapping frame, particullarly reinforced frame

Abstract: The material for injection to shroud a framework, and especially prestressed cables, is composed of 1.3-3.0 wt.% of inert hydrophilic particles in the cement mixture. They have a specific surface of more than 200 m /g, to give a fraction during mixing and/or injection into numerous fragments as small as 5 nanometres and as large as 300 nanometres. The particles are of precipitated silica.

“attrition-resistant iron-based fischer-tropsch catalysts”

Abstract: Operation of a Fischer-Tropsch (F-T) slurry bubble column reactors (SBCR) with an Fe catalyst is seriously limited due to attrition of the iron catalysts. The objective of this work is to develop a better understanding of the parameters affecting attrition resistance of Fe F-T catalysts suitable for use in SBCRs and to incorporate this understanding into the design of novel Fe catalyst having superior attrition resistance, activity, and selectivity. The effect of silica addition via coprecipitation and as a binder to a doubly promoted Fischer-Tropsch synthesis iron catalyst (100 Fe/5 Cu/4.2 K) was studied. The catalysts were prepared by coprecipitation, followed by binder silica addition and spray drying. A number of attrition methods including fluidized-bed, jet-cup, and ultrasound were developed for small quantities of catalysts and their results were compared with a standard ASTM method (D-5757-95). Binder silica addition up to a level of 10-12 wt % resulted in increased attrition resistance. Addition of precipitated silica, however, was found to be detrimental to attrition resistance and resulted in increased methane and reduced wax formation. An attrition resistant, active and selective catalyst was prepared that gave 95% CO conversion through 100 hours of testing in a fixed-bed at 250 C, 1.5 MPa and 1800 per hour space velocity with C selectivity of >78% and CH 0 + 5 4 selectivity of less than 5%.