Precipitated silica and its manufacturing method

Abstract

The present disclosure provides a method for producing a granular material having an average primary particle size of more than 80 nm and an average primary particle size of 10 to 40 nm. 2 / g, a total mercury intrusion volume of 0.75-2.00 cc / g, and an oil absorption of 60-120 cc / 100 g. The silica of the present invention is produced by a process comprising the steps of: (a) continuously feeding acid and alkali metal silicate or alkaline earth metal into a liquid medium with stirring at a silicate addition rate V1 and a temperature of 70-96°C to form silica particles; (b) stopping the feeding of alkali metal silicate or alkaline earth metal silicate and acid, and then raising the temperature to 90-100°C with stirring; (c) adding alkali metal silicate or alkaline earth metal silicate and acid with stirring, the silicate addition rate being 1-40% of the silicate addition rate V1, and adjusting the acid rate to keep the pH value constant at 9.0-10.0 during the addition of the alkali metal silicate or alkaline earth metal silicate; and (d) stopping the addition of alkali metal silicate or alkaline earth metal silicate and adding acid with stirring until the pH is 5.0-7.0. The precipitated silica of the present invention is used in cosmetics, anti-caking flow agents, foods, carrier applications, dentifrices and mouthwashes.

Description

[Technical field]

[0001] The present disclosure relates generally to precipitated silica and methods of making and using same.

[0002] background Porous precipitated silicas are usually produced by the reaction of an alkaline silicate solution (e.g. sodium silicate) with a mineral acid. Commercially, sulfuric acid is mostly used, but other acids such as hydrochloric acid can also be applied. The acid and sodium silicate solution are added simultaneously to water with stirring. Precipitated silica results when the silica precipitates from this dispersion by a neutralization reaction, producing a by-product sodium salt (sodium sulfate). Precipitated silica consists of aggregates (secondary particles) of primary (or ultimate) colloidal silica particles. The primary particles are approximately spherical and usually have a diameter in the range of 5-50 nm. The primary particles in the aggregates are covalently bonded to each other by the formation of siloxane bonds. Aggregates are three-dimensional clusters of these primary particles. The diameter of the aggregates is up to 500 nm. The aggregates are not chemically bonded into a huge gel network during the production process. The aggregates themselves may be physically bonded by the formation of hydrogen bonds between the surface silanol groups before milling to produce large agglomerates up to 100 μm in diameter. The median size of the agglomerates is about 20-50 μm in diameter (before grinding). The porosity and surface area of ​​these precipitated silica particles depend on the size of the primary particles and how they are aggregated and agglomerated. The pores are formed by the spaces between the primary particles and between the aggregates. Typical surface areas of commercially available precipitated silicas are between 5 and 800 m. 2 / g. They are sold as powders. The tap density, which is an index of the weight of these porous powders, is 50 to 500 kg / m 3 These have a high absorption capacity of about 175-320g / 100g.

[0003] In the specification of U.S. Pat. No. 8,597,425, it is reported that porous precipitated silica having a primary particle size of 10 to 80 nm is useful for applications such as rubber and tires, battery separators, antiblocking agents, matting agents for inks and paints, carriers for agricultural products and feed, coating materials, printing inks, fire extinguishing powders, plastics, non-impact printing fields, paper pulp, and personal care items.

[0004] J. Soc Cosmet. Chem August 1978, 29, 497-521 reports that precipitated silica with a primary particle size of 12 to 51 nm is useful for cosmetic applications such as toothpaste.

[0005] The commercial product SIPERNAT 22, useful as a carrier and anti-caking free-flow additive in food and feed applications, has a reported primary particle size of 18 nm (Degussa literature No. 64, Physiological Behavior of highly dispersed Oxides of Silicon, Aluminum and Titanium 1978, page 26-27).

[0006] In the specification of U.S. Pat. No. 6,946,119, a precipitated silica product containing silica fine particles is described, in which the silica fine particles have a concentration of 1 to 50 μm. 2 Disclosed is a precipitated silica product comprising silica particles having a median diameter of 1 to 100 micrometers supporting a surface deposit thereon comprising an active precipitated amorphous silica material present in an amount effective to provide a BET specific surface area of ​​100 μm / g. The precipitated silica is used in oral care applications.

[0007] U.S. Pat. No. 7,255,852 discloses a precipitated silica comprising silica product particles having a porous surface, the silica particles having a cumulative surface area of ​​all pores having a diameter greater than 500 Å of 8 m2 as measured by mercury intrusion porosimetry. 2 / g and the BET specific surface area is about 20 m 2 / g and a cetylpyridinium chloride compatibility (% CPC) of greater than 55% are described. The precipitated silicas are used in oral care applications.

[0008] U.S. Patent No. 7,438,895 describes an abrasive precipitated silica material having a coating of precipitated silica that is denser than the material to which it is applied, the coated precipitated silica material having a median particle size of 5.5 to 8 microns and a pore area of ​​up to about 2.4 m for pores having a diameter greater than 500 Å. 2 / g and having at least 90% cetylpyridinium chloride compatibility after aging the material at 140° F. for 7 days.

[0009] US Patent Publication No. 20080160053 describes a method for producing an abrasive silica material comprising the successive steps of: reacting together under high shear mixing conditions a first amount of silicate and a first amount of acid in the presence of at least one electrolyte, optionally present in an amount of 5-25% by weight relative to the dry weight of the first amount of said silicate, to form a first silica material; and reacting together in the presence of the first silica material a second amount of silicate and a second amount of acid, optionally present in the presence of at least one electrolyte, optionally present in an amount of 5-25% by weight relative to the dry weight of the second amount of said silicate, to form a dense phase coating on a surface of the first silica material, thereby forming a silica-coated silica material, wherein the at least one electrolyte is present during either or both steps "a" or "b", and wherein step "b" is optionally performed under high shear mixing conditions.

[0010] U.S. Pat. No. 10,328,002 describes a dentifrice composition containing an abrasive, the abrasive having a BET surface area of ​​about 0.1 to about 9 m. 2 / g and has a compacted bulk density of about 35 to about 55 lb / ft 3A dentifrice composition is disclosed that comprises precipitated silica particles characterized by a mercury abrasion value in the range of about 8 to about 25 mg loss / 100,000 revolutions, a total mercury intrusion pore volume in the range of about 0.4 to 1.2 cc / g, and a stannous compatibility in the range of about 70 to about 99%, wherein the abrasive comprises large pores having a size of about 1000 angstroms or greater and does not comprise small pores having a size of less than about 500 to 1000 angstroms.

[0011] WO 2018114280 describes silica particles having a BET surface area of ​​about 0.1 to about 7 m 2 / g and has a compacted bulk density of about 35 to about 55 lb / ft 3 in the range of about 8 to about 25 mg loss / 100,000 revolutions, a total mercury intrusion pore volume in the range of about 0.7 to about 1.2 cc / g, and (v) a stannous compatibility in the range of about 70 to about 99%.

[0012] US Patent Publication No. 20190374448 describes a dentifrice composition comprising a binder, a surfactant, and silica particles, the silica particles having a d50 median particle size in the range of about 4 to about 25 μm and a d50 median particle size in the range of 0 to about 10 μm. 2 Dentifrice compositions are disclosed that include a BET surface area in the range of about 0.2 to about 1.5 cc / g and a total mercury intrusion pore volume in the range of about 0.2 to about 1.5 cc / g.

[0013] WO 2019238777 describes silica particles having the following characteristics: (i) a d50 median particle size in the range of about 8 to about 20 μm, (ii) a sphericity coefficient (S80) of about 0.9 or greater, (iii) a sphericity coefficient (S80) of about 0.1 to about 8 μm. 2 / g range, (iv) a total mercury intrusion pore volume in the range of about 0.35 to about 0.8 cc / g, and (v) a loss on ignition (LOI) in the range of about 3 to about 7 wt.%.

[0014] The ability of precipitated silica to provide the right balance of cleaning and abrasion while providing compatibility with each ingredient is important in toothpaste formulations. None of the prior art addresses the lack of compatibility with other ingredients such as CPC and BAC, or compatibility with flavors, while simultaneously achieving PCR (80-110) and RDA (100-220) values ​​in the normal range.

[0015] overview We have now found that silica with a large primary particle size can provide high compatibility with CPC, BAC and / or flavors in oral care applications while having acceptable PCR / RDA values ​​within the range of current silica detergents.

[0016] The subject of the present invention is therefore a method for producing granular granular particles having a mean primary particle size of more than 80 nm, preferably more than 90 nm, more preferably more than 100 nm, still more preferably more than 110 nm, most preferably between 120 nm and 500 nm, a mean primary particle size of 10 to 40 nm, 2 / g, preferably 10 to 26 m 2 / g, more preferably 10 to 23 m 2 / g, most preferably 10 to 20m 2 / g, a total mercury intrusion volume of 0.75-2.00 cc / g, preferably 0.80-1.80 cc / g, more preferably 0.85-1.65 cc / g, more preferably 0.90-1.50 cc / g, and an oil absorption of 60-120 cc / 100g, preferably 60-110 cc / 100g, more preferably 60-100 cc / 100g, and most preferably 60-90 cc / 100g.

[0017] The subject of the present invention is also (a) continuously feeding an acid and an alkali metal silicate or an alkaline earth metal silicate into a liquid medium with stirring at a silicate addition rate V1 and at a temperature of 70-96°C to form silica particles; (b) stopping the supply of alkali metal silicate or alkaline earth metal silicate and acid, and then increasing the temperature with stirring to 90 to 100°C, preferably 94 to 96°C; (c) adding an alkali metal or alkaline earth metal silicate and an acid with stirring, the silicate addition rate being 1-40%, preferably 1-30%, more preferably 2-10%, even more preferably 3-5% of the silicate addition rate V1, and by adjusting the acid rate the pH value is kept constant during the addition of the alkali metal or alkaline earth metal silicate at 9.0-10.0, preferably 9.5-9.9, more preferably 9.6-9.8; (d) stopping the addition of the alkali metal silicate or alkaline earth metal silicate and adding acid with stirring until the pH is 5.0 to 7.0, preferably 5.5 to 6.5. The method includes:

[0018] A further subject of the present invention is the use of the silicas according to the invention in cosmetics, anti-caking flow agents, food, carrier applications, dentifrices and mouthwashes.

[0019] Detailed Description of the Invention The precipitated silica of the present invention has an average primary particle size of more than 80 nm, preferably more than 90 nm, more preferably more than 100 nm, even more preferably more than 110 nm, and most preferably between 120 nm and 500 nm, a mean particle size of 10 to 40 nm, 2 / g, preferably 10 to 26 m 2 / g, more preferably 10 to 23 m 2 / g, most preferably 10 to 20m 2 / g, a total mercury intrusion volume of 0.75 to 2.00 cc / g, preferably 0.80 to 1.80 cc / g, more preferably 0.85 to 1.65 cc / g, more preferably 0.90 to 1.50 cc / g, and an oil absorption of 60 to 120 cc / 100g, preferably 60 to 110 cc / 100g, more preferably 60 to 100 cc / 100g, and most preferably 60 to 90 cc / 100g.

[0020] The silica of the present invention has a high primary particle size.

[0021] The precipitated silica according to the present invention has a particle size of 10 to 35 m 2 / g, preferably 20 to 30m 2 / g of CTAB surface area.

[0022] The precipitated silica according to the present invention has a density of 0.40 to 0.80 g / cm 3 , preferably 0.48 to 0.75 g / cm 3 The composition may have a firm bulk density of 0.01 to 0.01 mm.

[0023] The precipitated silica according to the invention may have an Einlehner value of less than 18 mg loss / 100k revolutions, preferably between 3 and 18 mg loss / 100k revolutions.

[0024] The C content of the silica according to the present invention may be less than 3%, preferably less than 1%, more preferably between 0% and 0.5%, and most preferably between 0% and 0.1%.

[0025] The precipitated silica according to the present invention has a primary particle size average of more than 90 nm and a particle size average of 10 to 26 nm. 2 / g BET surface area, a total mercury intrusion volume of 0.75 to 2.00 cc / g, and an oil absorption of 60 to 120 cc / 100 g.

[0026] The precipitated silica according to the present invention has a primary particle size average of more than 80 nm and a mean particle size of 10 to 30 nm. 2 / g BET surface area, 0.80-1.80 cc / g total mercury intrusion volume, and 70-110 cc / 100 g oil absorption.

[0027] The precipitated silica according to the present invention has a primary particle size average of more than 90 nm and a particle size average of 10 to 26 nm. 2 / g BET surface area, 0.80-1.80 cc / g total mercury intrusion volume, and 70-110 cc / 100 g oil absorption.

[0028] The precipitated silica according to the present invention has a primary particle size average of more than 100 nm and a particle size average of 10 to 23 nm. 2 / g BET surface area, a total mercury intrusion volume of 0.75 to 2.00 cc / g, and an oil absorption of 60 to 120 cc / 100 g.

[0029] The precipitated silica according to the present invention has a primary particle size average of more than 80 nm and a mean particle size of 10 to 30 nm. 2 / g BET surface area, a total mercury intrusion volume of 0.85 to 1.65 cc / g, and an oil absorption of 60 to 100 cc / 100 g.

[0030] The precipitated silica according to the present invention has a primary particle size average of more than 100 nm and a particle size average of 10 to 23 nm. 2 / g BET surface area, a total mercury intrusion volume of 0.85 to 1.65 cc / g, and an oil absorption of 60 to 100 cc / 100 g.

[0031] The precipitated silica according to the present invention has a primary particle size average of 120 to 500 nm and a particle size average of 10 to 20 nm. 2 / g BET surface area, a total mercury intrusion volume of 0.75 to 2.00 cc / g, and an oil absorption of 60 to 120 cc / 100 g.

[0032] The precipitated silica according to the present invention has a primary particle size average of more than 80 nm and a mean particle size of 10 to 30 nm. 2 / g BET surface area, 0.90-1.50 cc / g total mercury intrusion volume, and 60-90 cc / 100 g oil absorption.

[0033] The precipitated silica according to the present invention has a primary particle size average of 120 to 500 nm and a particle size average of 10 to 20 nm. 2 / g BET surface area, 0.90-1.50 cc / g total mercury intrusion volume, and 60-90 cc / 100 g oil absorption.

[0034] The method according to the invention comprises at least four steps: (a) continuously feeding an acid and an alkali metal silicate or an alkaline earth metal silicate into a liquid medium with stirring at a silicate addition rate V1 and at a temperature of 70-96°C to form silica particles; (b) stopping the supply of alkali metal silicate or alkaline earth metal silicate and acid, and then increasing the temperature with stirring to 90 to 100°C, preferably 94 to 96°C; (c) adding an alkali metal silicate or alkaline earth metal silicate and an acid with stirring, the silicate addition rate being 1-40%, preferably 5-30%, more preferably 7-25%, even more preferably 10-20% of the silicate addition rate V1, and by adjusting the acid rate the pH value is kept constant at 9.0-10.0, preferably 9.5-9.9, more preferably 9.6-9.8 during the addition of the alkali metal silicate or alkaline earth metal silicate; (d) stopping the addition of the alkali metal silicate or alkaline earth metal silicate and adding acid with stirring until the pH is 5.0 to 7.0, preferably 5.5 to 6.5. Includes.

[0035] The silica from step (d) may be filtered (step (e)), for example with a filter press.

[0036] The silica from step (e) may be dried (step (f)), for example in a spray dryer.

[0037] The silica of step (f) may be ground.

[0038] Preferably, 35 to 65% of the total volume of the alkali metal silicate or alkaline earth metal silicate is added during step (a).

[0039] The liquid medium in step (a) is an alkali metal silicate or an alkaline earth metal silicate and water.

[0040] The temperature range in step (a) may be 70 to 95°C, preferably 70 to 90°C, and more preferably 80 to 90°C.

[0041] The acid rate in step (a) may be sufficient to maintain a pH between 8.5 and 10.5, more preferably between 9.5 and 10.2.

[0042] The silicate rate in step (c) may be slowed to 5-30%, more preferably 10-20%, of the rate in step (a).

[0043] The alkali metal silicate in steps (a) and (c) may preferably be sodium silicate.

[0044] The rate of silicate addition in step (c) can be adjusted so that the % / hr of silicate added in this step relative to the total amount of silicate added in the batch is less than 30% / hr, preferably 15-25% / hr. The % / hr of silicate added is calculated as: volume of silicate used in step (c) / time of step (c) / volume of silicate used in steps (a) and (c)×100.

[0045] The acid in steps (a), (c) and (d) may preferably be sulfuric acid.

[0046] The duration of step (c) may be from 100 to 500 minutes, preferably from 150 to 300 minutes.

[0047] The precipitated silica of the present invention can be produced by the process of the present invention.

[0048] The precipitated silica of the present invention can be used in cosmetics, anti-caking flow agents, food, carrier applications, dentifrices and mouthwashes.

[0049] The precipitated silica of the present invention has improved compatibility with cetylpyridinium chloride (CPC), benzalkonium chloride (BAC) and flavors in oral care applications. EXAMPLES

[0050] · Primary particle size average by SEM Images were taken at 50,000x magnification using scanning electron microscopy. Images were sputtered with platinum, taking care not to introduce texture into the particle surface due to the sputtering, as this could be mistaken for a primary structure. Images should be representative of the entire sample and contain a minimum of 30 particles. Primary particles were then measured. If particles were not perfectly round, the smallest diameter across each particle was used. Particles at the edge of the image that could not be completely viewed should not be used. Mean and median values ​​were then calculated based on the data set.

[0051] Carbon content Carbon content was measured with a LECO SC832 carbon / sulfur analyzer.

[0052] Brightness Silica samples were pressed into pellets with a smooth surface and analyzed using a Technidyne Brightmeter S-5 / BC. The instrument is equipped with dual beam optics, illuminating the sample at a 45° angle and viewing the reflected light at 0°. This is in accordance with TAPPI test methods T452 and T646, and ASTM standard D985. The powder material is pressed into pellets of approximately 1 cm with sufficient pressure to obtain a pellet surface that is smooth, free of loose particles and gloss.

[0053] ·moisture Moisture was measured by heating the silica at 105°C for 2 hours.

[0054] ·BET surface area The BET surface area of ​​the silica of the present invention was measured using a Micromeritics TriStar 3020 instrument by the BET nitrogen adsorption method of Brunaur et al., J. Am. Chem. Soc., 60, 309 (1938), known in the art of particulate materials such as silica and silicate materials.

[0055] ·Oil absorption amount Oil absorption values ​​were measured (cc of oil absorbed per 100 g of particles) using linseed oil by the rubbing out method described in ASTM D281. Generally, higher oil absorption levels indicate particles with higher structure, while lower values ​​indicate particles with lower structure.

[0056] Total mercury injection volume The intruded mercury volume or total pore volume (Hg) was measured by mercury porosimetry using a Micromeritics AutoPore IV 9520 (or Micromeritics AutoPore V9620) instrument. Pore size was calculated using the Washburn equation with a contact angle theta (θ) of 130° and a surface tension γ of 484 dynes / cm. Mercury was forced into the voids of the particles as a function of pressure, and the volume of intruded mercury per gram of sample at each pressure setting was calculated. The total pore volume reported herein represents the cumulative volume of intruded mercury at pressures from vacuum to 60,000 psi. The increase in volume (cm) at each pressure setting was calculated using the Washburn equation. 3 The indentation volume (p / g) was plotted against the pore radius or diameter corresponding to the increment of pressure setting. The peak of the indentation volume vs. pore radius or diameter curve corresponds to the mode of the pore size distribution and identifies the most common pore size in the sample. Specifically, the sample size was adjusted to give 25-90% stem volume in a powder penetrometer with a 5 mL valve and stem volume of approximately 1.1 mL. The sample was evacuated to a pressure of 50 μmHg and held for 5 min. Mercury filled the pores at 4.0-60,000 psi, with an equilibration time of 10 s at each data collection point. The total pore volume mentioned above captures the volume due to intraparticle porosity resulting from the pore structure within individual particles and interparticle porosity formed from the gaps between packed particles under pressure. To better separate and measure and test the actual intraparticle porosity of the produced amorphous silica, the pore volume of pores smaller than 0.11 μm can be used.

[0057] Einlehner An Einlehner AT-1000 Abrader is used as follows: (1) a previously cleaned and dried Fourdrinier brass wire screen is then weighed and exposed for a certain period of time to the action of a 10% aqueous silica suspension, specifically a 100 g sample applied to 900 g deionized water; (2) the abrasion is then determined as the number of milligrams of brass lost from the Fourdrinier wire screen per 100,000 revolutions. The results, measured in mg loss, are characterized as the 10% brass Einlehner (BE) abrasion value.

[0058] ·CTAB surface area The CTAB surface area disclosed herein was determined by absorption of CTAB (cetyltrimethylammonium bromide) on the silica surface, separation of the excess by centrifugation, and quantification by titration with sodium lauryl sulfate using a surfactant electrode. Specifically, approximately 0.5 g of silica particles were placed in a 250 mL beaker containing 100 mL of CTAB solution (5.5 g / L), mixed on an electric stir plate for 1 hour, and then centrifuged at 10,000 RPM for 30 minutes. 1 mL of 10% TritonX-100 was added to 5 mL of the clear supernatant in the 100 mL beaker. The pH was adjusted to 3-3.5 with 0.1 N HCl and titrated with 0.01 M sodium lauryl sulfate using a surfactant electrode (Brinkmann SUR1501-DL) to determine the endpoint.

[0059] Particle size The particle size of the silica of the present invention was measured based on the angle of scattered laser light using a HORIBA Laser Scattering Dry Particle Size Distribution Analyzer LA-960.

[0060] - Moisture-corrected AbC value Water absorption values ​​were determined using an Absorptometer "C" torque rheometer manufactured by CW Brabender Instruments, Inc. Approximately 1 / 3 cup of the silica sample was transferred to the mixing chamber of the Absorptometer and mixed at 150 RPM. Water was then added at a rate of 6 mL / min and the torque required to mix the powder was recorded. As the water was absorbed into the powder, the torque reached a maximum as the powder changed from a flowable to a paste-like form. The total volume of water added when the maximum torque was reached is then normalized to the amount of water that 100 g of powder can absorb. Since the powder was used in its as-received (wet) state, the free moisture value of the powder was used to calculate the "moisture corrected water AbC value" using the following formula:

[0061]

number

[0062] ·5wt% pH 5.0 g of the sample was weighed out to the nearest 0.1 g, and the weighed sample was transferred to a 250 mL beaker to measure the 5% pH. 95 mL of deionized water was added and the sample was stirred for 5 minutes. The pH was then measured with a pH meter while stirring the sample.

[0063] Tight and loose bulk density The compacted and loose bulk densities were measured by placing 20.0 g of sample in a 250 mL graduated cylinder with a flat rubber base. The initial volume was recorded and divided by the weight of the sample used to calculate the loose bulk density. The cylinder was then placed in a tapped density measuring device and a cam was rotated at a constant rate. The cam was designed to raise and lower the cylinder a distance of 5.715 cm per second for a period of typically 15 minutes until the sample volume was constant. The final volume was recorded and divided by the weight of the sample used to calculate the compacted bulk density.

[0064] [Example 1A (Example according to the present invention)] 383 mL of sodium silicate (2.65 MR, 1.193 g / mL) and 957 mL of water were added to a 7 L laboratory size reactor and heated to 85° C. with stirring at 350 RPM with an overhead stirrer equipped with a propeller blade. Once 85° C. was reached, sodium silicate (2.65 MR, 1.193 g / mL) and sulfuric acid (1.121 g / mL) were added simultaneously at rates of 39.0 mL / min and 16.4 mL / min, respectively, over a period of 38 minutes. After 38 minutes, the flows of sodium silicate and sulfuric acid were stopped and the reaction mixture was heated to 95° C. Once 95° C. was reached, sodium silicate (2.65 MR, 1.193 g / mL) was added at 10.2 mL / min and sulfuric acid (1.121 g / mL) was added at a rate sufficient to maintain a pH of 9.6 (±0.1) over an additional 150 minutes. After this additional 150 minutes, the sodium silicate flow was stopped and sulfuric acid (1.121 g / mL) was continued at a rate of 5.1 mL / min to adjust the pH to 6.0. Once the pH stabilized at 6.0, the batch was filtered, washed with 14 L of water, and dried at 105° C. overnight.

[0065] [Example 1B (Example according to the present invention)] 273 mL of sodium silicate (2.65 MR, 1.193 g / mL) and 681 mL of water were added to a 7 L laboratory size reactor and heated to 85° C. with stirring at 350 RPM with an overhead stirrer equipped with a propeller blade. Once 85° C. was reached, sodium silicate (2.65 MR, 1.193 g / mL) and sulfuric acid (1.121 g / mL) were added simultaneously at rates of 27.7 mL / min and 11.7 mL / min, respectively, over a period of 38 minutes. After 38 minutes, the flows of sodium silicate and sulfuric acid were stopped and the reaction mixture was heated to 95° C. Once 95° C. was reached, sodium silicate (2.65 MR, 1.193 g / mL) was added at 10.7 mL / min and sulfuric acid (1.121 g / mL) was added at a rate sufficient to maintain a pH of 9.6 (±0.1) over an additional 210 minutes. After this additional 210 minutes, the sodium silicate flow was stopped and sulfuric acid (1.121 g / mL) was continued at a rate of 5.1 mL / min to adjust the pH to 6.0. Once the pH stabilized at 6.0, the batch was filtered, washed with 14 L of water, and dried at 105° C. overnight.

[0066] [Example 1C (Example according to the present invention)] 273 mL of sodium silicate (2.65 MR, 1.193 g / mL) and 681 mL of water were added to a 7 L laboratory size reactor and heated to 85° C. with stirring at 350 RPM with an overhead stirrer equipped with a propeller blade. Once 85° C. was reached, sodium silicate (2.65 MR, 1.193 g / mL) and sulfuric acid (1.121 g / mL) were added simultaneously at rates of 43.8 mL / min and 18.4 mL / min, respectively, over a period of 38 minutes. After 38 minutes, the flows of sodium silicate and sulfuric acid were stopped and the reaction mixture was heated to 95° C. Once 95° C. was reached, sodium silicate (2.65 MR, 1.193 g / mL) was added at 9.8 mL / min and sulfuric acid (1.121 g / mL) was added at a rate sufficient to maintain a pH of 9.6 (±0.1) over an additional 120 minutes. After this additional 120 minutes, the sodium silicate flow was stopped and sulfuric acid (1.121 g / mL) was continued at a rate of 4.7 mL / min to adjust the pH to 6.0. Once the pH stabilized at 6.0, the batch was filtered, washed with 14 L of water, and dried at 105° C. overnight.

[0067] [Example 2A (Example according to the present invention)] 320 mL of sodium silicate (2.65 MR, 1.193 g / mL) and 824 mL of water were added to a 7 L laboratory size reactor and heated to 85° C. with stirring at 350 RPM with an overhead stirrer equipped with a propeller blade. Once 85° C. was reached, sodium silicate (2.65 MR, 1.193 g / mL) and sulfuric acid (1.121 g / mL) were added simultaneously at rates of 33.8 mL / min and 15.1 mL / min, respectively, over a period of 47 minutes. After 47 minutes, the flows of sodium silicate and sulfuric acid were stopped and the reaction mixture was heated to 95° C. Once 95° C. was reached, sodium silicate (2.65 MR, 1.193 g / mL) was added at 10.4 mL / min and sulfuric acid (1.121 g / mL) was added at a rate sufficient to maintain a pH of 9.6 (±0.1) over an additional 150 minutes. After this additional 150 minutes, the sodium silicate flow was stopped and sulfuric acid (1.121 g / mL) was continued at a rate of 5.0 mL / min to adjust the pH to 6.0. Once the pH stabilized at 6.0, the batch was filtered, washed with 14 L of water, and dried at 105° C. overnight.

[0068] Table 1 shows the analytical values ​​for each example.

[0069] [Table 1]

[0070] [Comparative example 5A] 594 mL of sodium silicate (2.65 MR, 1.193 g / mL, heated to 80° C.) and 1483 mL of water were added to a 7 L reactor and heated to 85° C. with 350 RPM stirring. Once 85° C. was reached, sodium silicate (2.65 MR, 1.193 g / ml, heated to 80° C.) and sulfuric acid (1.121 g / mL) were added simultaneously at rates of 60.4 mL / min and 25.3 mL / min, respectively, over a period of 38 minutes. After 38 minutes, the sodium silicate flow was stopped and sulfuric acid (1.121 g / mL) was continued at a rate of 25.3 mL / min to adjust the pH to 6.0. Once the pH stabilized at 6.0, the batch was filtered, washed with 14 L of water, and dried in an oven overnight.

[0071] [Comparative Example 5B] 594 mL of sodium silicate (2.65 MR, 1.193 g / mL, heated to 80° C.) and 1483 mL of water were added to a 7 L reactor and heated to 85° C. with 350 RPM stirring. Once 85° C. was reached, sodium silicate (2.65 MR, 1.193 g / ml, heated to 80° C.) and sulfuric acid (1.121 g / mL) were added simultaneously at rates of 60.4 mL / min and 21.6 mL / min, respectively, over a period of 38 minutes. After 38 minutes, the sodium silicate flow was stopped and sulfuric acid (1.121 g / mL) was continued at a rate of 21.6 mL / min to adjust the pH to 6.0. Once the pH stabilized at 6.0, the batch was filtered, washed with 14 L of water, and dried in an oven overnight.

[0072] [Comparative Example 5C] 594 mL of sodium silicate (2.65 MR, 1.193 g / mL, heated to 80° C.) and 1483 mL of water were added to a 7 L reactor and heated to 85° C. with 350 RPM stirring. Once 85° C. was reached, sodium silicate (2.65 MR, 1.193 g / ml, heated to 80° C.) and sulfuric acid (1.121 g / mL) were added simultaneously at rates of 60.4 mL / min and 29.2 mL / min, respectively, over a period of 38 minutes. After 38 minutes, the sodium silicate flow was stopped and sulfuric acid (1.121 g / mL) was continued at a rate of 29.2 mL / min to adjust the pH to 6.0. Once the pH stabilized at 6.0, the batch was filtered, washed with 14 L of water, and dried in an oven overnight.

[0073] [Comparative Example 5D] 594 mL of sodium silicate (2.65 MR, 1.193 g / mL, heated to 80° C.) and 1483 mL of water were added to a 7 L reactor and heated to 85° C. with 350 RPM stirring. Once 85° C. was reached, sodium silicate (2.65 MR, 1.193 g / ml, heated to 80° C.) and sulfuric acid (1.121 g / mL) were added simultaneously at rates of 60.4 mL / min and 29.2 mL / min, respectively, over a period of 38 minutes. After 38 minutes, the sodium silicate flow was stopped and sulfuric acid (1.121 g / mL) was continued at a rate of 29.2 mL / min to adjust the pH to 6.0. Once the pH stabilized at 6.0, the batch was filtered, washed with 14 L of water, and dried in an oven overnight.

[0074] [Comparative Example 5E] 594 mL of sodium silicate (2.65 MR, 1.193 g / mL, heated to 80° C.) and 1483 mL of water were added to a 7 L reactor and heated to 85° C. with 350 RPM stirring. Once 85° C. was reached, sodium silicate (2.65 MR, 1.193 g / mL, heated to 80° C.) and sulfuric acid (1.121 g / mL) were added simultaneously at rates of 60.4 mL / min and 19.1 mL / min, respectively, over a period of 38 minutes. After 38 minutes, the sodium silicate flow was stopped and sulfuric acid (1.121 g / mL) was continued at a rate of 19.1 mL / min to adjust the pH to 6.0. Once the pH stabilized at 6.0, the batch was filtered, washed with 14 L of water, and dried in an oven overnight.

[0075] Table 2 shows the analytical values ​​for each example.

[0076] [Table 2]

[0077] [Comparative Example 6A] 594 mL of sodium silicate (2.65 MR, 1.193 g / mL, heated to 80° C.) and 1483 mL of water were added to a 7 L reactor and heated to 80° C. with 350 RPM stirring. Once 85° C. was reached, sodium silicate (2.65 MR, 1.193 g / mL, heated to 80° C.) and sulfuric acid (1.121 g / mL) were added simultaneously at rates of 60.4 mL / min and 21.6 mL / min, respectively, over a period of 38 minutes. After 38 minutes, the sodium silicate flow was stopped and sulfuric acid (1.121 g / mL) was continued at a rate of 21.6 mL / min to adjust the pH to 6.0. Once the pH stabilized at 6.0, the batch was filtered, washed with 14 L of water, and dried in an oven overnight.

[0078] [Comparative Example 6B] 594 mL of sodium silicate (2.65 MR, 1.193 g / mL, heated to 85° C.) and 1483 mL of water were added to a 7 L reactor and heated to 90° C. with 350 RPM stirring. Once 85° C. was reached, sodium silicate (2.65 MR, 1.193 g / mL, heated to 85° C.) and sulfuric acid (1.121 g / mL) were added simultaneously at rates of 60.4 mL / min and 21.6 mL / min, respectively, over a period of 38 minutes. After 38 minutes, the sodium silicate flow was stopped and sulfuric acid (1.121 g / mL) was continued at a rate of 21.6 mL / min to adjust the pH to 6.0. Once the pH stabilized at 6.0, the batch was filtered, washed with 14 L of water, and dried in an oven overnight.

[0079] [Comparative Example 6C] 594 mL of sodium silicate (2.65 MR, 1.193 g / mL, heated to 90° C.) and 1483 mL of water were added to a 7 L reactor and heated to 95° C. with stirring at 350 RPM. Once 85° C. was reached, sodium silicate (2.65 MR, 1.193 g / ml, heated to 90° C.) and sulfuric acid (1.121 g / mL) were added simultaneously at rates of 60.4 mL / min and 21.6 mL / min, respectively, over a period of 38 minutes. After 38 minutes, the sodium silicate flow was stopped and sulfuric acid (1.121 g / mL) was continued at a rate of 21.6 mL / min to adjust the pH to 6.0. Once the pH stabilized at 6.0, the batch was filtered, washed with 14 L of water, and dried in an oven overnight.

[0080] Table 3 shows the analytical values ​​for each example.

[0081] [Table 3]

[0082] [Comparative Example 7A] 594 mL of sodium silicate (2.65 MR, 1.193 g / mL, heated to 80° C.) and 1483 mL of water were added to a 7 L reactor and heated to 85° C. with stirring at 650 RPM. Once 85° C. was reached, sodium silicate (2.65 MR, 1.193 g / mL, heated to 80° C.) and sulfuric acid (1.121 g / mL) were added simultaneously at rates of 60.4 mL / min and 25.4 mL / min, respectively, over a period of 38 minutes. After 38 minutes, the sodium silicate flow was stopped and sulfuric acid (1.121 g / mL) was continued at a rate of 25.4 mL / min to adjust the pH to 6.0. Once the pH stabilized at 6.0, the batch was filtered, washed with 14 L of water, and dried in an oven overnight.

[0083] Table 4 shows the analytical values ​​in this example.

[0084] [Table 4]

[0085] [Comparative Example 8A] 510 mL of sodium silicate (2.65 MR, 1.193 g / mL, heated to 80° C.) and 1310 mL of water were added to a 7 L reactor and heated to 80° C. with 350 RPM stirring. Once 85° C. was reached, sodium silicate (2.65 MR, 1.193 g / mL, heated to 80° C.) and sulfuric acid (1.121 g / mL) were added simultaneously at rates of 53.7 mL / min and 24.0 mL / min, respectively, over a period of 38 minutes. After 38 minutes, the sodium silicate flow was stopped and sulfuric acid (1.121 g / mL) was continued at a rate of 24.0 mL / min to adjust the pH to 6.0. Once the pH stabilized at 6.0, the batch was filtered, washed with 14 L of water, and dried in an oven overnight.

[0086] [Comparative Example 8B] 510 mL of sodium silicate (2.65 MR, 1.193 g / mL, heated to 80° C.) and 1310 mL of water were added to a 7 L reactor and heated to 80° C. with 350 RPM stirring. Once 85° C. was reached, sodium silicate (2.65 MR, 1.193 g / ml, heated to 80° C.) and sulfuric acid (1.121 g / mL) were added simultaneously at rates of 53.7 mL / min and 27.5 mL / min, respectively, over a period of 38 minutes. After 38 minutes, the sodium silicate flow was stopped and sulfuric acid (1.121 g / mL) was continued at a rate of 27.5 mL / min to adjust the pH to 6.0. Once the pH stabilized at 6.0, the batch was filtered, washed with 14 L of water, and dried in an oven overnight.

[0087] [Comparative Example 8C] 510 mL of sodium silicate (2.65 MR, 1.193 g / mL, heated to 80° C.) and 1310 mL of water were added to a 7 L reactor and heated to 80° C. with 350 RPM stirring. Once 85° C. was reached, sodium silicate (2.65 MR, 1.193 g / ml, heated to 80° C.) and sulfuric acid (1.121 g / mL) were added simultaneously at rates of 53.7 mL / min and 20.4 mL / min, respectively, over a period of 38 minutes. After 38 minutes, the sodium silicate flow was stopped and sulfuric acid (1.121 g / mL) was continued at a rate of 20.4 mL / min to adjust the pH to 6.0. Once the pH stabilized at 6.0, the batch was filtered, washed with 14 L of water, and dried in an oven overnight.

[0088] [Comparative Example 8D] 510 mL of sodium silicate (2.65 MR, 1.193 g / mL, heated to 80° C.) and 1310 mL of water were added to a 7 L reactor and heated to 80° C. with 350 RPM stirring. Once 85° C. was reached, sodium silicate (2.65 MR, 1.193 g / mL, heated to 80° C.) and sulfuric acid (1.121 g / mL) were added simultaneously at rates of 53.7 mL / min and 19.2 mL / min, respectively, over a period of 38 minutes. After 38 minutes, the sodium silicate flow was stopped and sulfuric acid (1.121 g / mL) was continued at a rate of 19.2 mL / min to adjust the pH to 6.0. Once the pH stabilized at 6.0, the batch was filtered, washed with 14 L of water, and dried in an oven overnight.

[0089] [Comparative Example 8E] 510 mL of sodium silicate (2.65 MR, 1.193 g / mL, heated to 80° C.) and 1310 mL of water were added to a 7 L reactor and heated to 80° C. with 350 RPM stirring. Once 85° C. was reached, sodium silicate (2.65 MR, 1.193 g / mL, heated to 80° C.) and sulfuric acid (1.121 g / mL) were added simultaneously at rates of 53.7 mL / min and 18.0 mL / min, respectively, over a period of 38 minutes. After 38 minutes, the sodium silicate flow was stopped and sulfuric acid (1.121 g / mL) was continued at a rate of 18.0 mL / min to adjust the pH to 6.0. Once the pH stabilized at 6.0, the batch was filtered, washed with 14 L of water, and dried in an oven overnight.

[0090] Table 5 shows the analytical values ​​for each example.

[0091] [Table 5]

[0092] [Example 10A (Example according to the present invention)] 62 L of sodium silicate (2.65 MR, 1.193 g / mL, heated to 80° C.) and 154 L of water were added to a 1200 L reactor and heated to 85° C. with stirring at 80 RPM and recirculation at 80 L / min. Once at 85° C., sodium silicate (2.65 MR, 1.193 g / mL, heated to 80° C.) and sulfuric acid (1.121 g / mL) were added simultaneously at rates of 6.27 L / min and 2.24 L / min, respectively, over a period of 38 minutes. After the 38 minutes had elapsed, the sodium silicate and sulfuric acid flows were stopped and the reaction mixture was heated to 95° C. Once 95°C was reached, sodium silicate (2.65 MR, 1.193 g / mL, heated to 80°C) was added at 1.63 L / min over an additional 150 minutes, and sulfuric acid (1.121 g / mL) was added at a rate sufficient to maintain a pH of 9.6 (±0.1). After this additional 150 minutes, the sodium silicate flow was stopped and sulfuric acid (1.121 g / mL) was continued at a rate of 0.82 mL / min to adjust the pH to 6.0. Once the pH was stable at 6.0, the batch was filtered, washed to a conductivity of <1500 μS, spray dried to a target moisture of 5%, and milled to a particle size of approximately 10 μm.

[0093] [Example 10B (Example according to the present invention)] 53 L of sodium silicate (2.65 MR, 1.193 g / mL, heated to 80° C.) and 133 L of water were added to a 1200 L reactor and heated to 85° C. with stirring at 80 RPM and recirculation at 80 L / min. Once 85° C. was reached, sodium silicate (2.65 MR, 1.193 g / ml, heated to 80° C.) and sulfuric acid (1.121 g / mL) were added simultaneously at rates of 5.42 L / min and 1.82 L / min, respectively, over a period of 38 minutes. After the 38 minutes had elapsed, the sodium silicate and sulfuric acid flows were stopped and the reaction mixture was heated to 95° C. Once 95°C was reached, sodium silicate (2.65 MR, 1.193 g / mL, heated to 80°C) was added at 1.63 L / min over an additional 180 minutes, and sulfuric acid (1.121 g / mL) was added at a rate sufficient to maintain a pH of 9.6 (±0.1). After this additional 180 minutes, the sodium silicate flow was stopped and sulfuric acid (1.121 g / mL) was continued at a rate of 0.82 mL / min to adjust the pH to 6.0. Once the pH was stable at 6.0, the batch was filtered, washed to a conductivity of less than 1500 μS, spray dried to a target moisture of 5%, and milled to a particle size of approximately 10 μm.

[0094] [Example 10C (Example according to the present invention)] 44 L of sodium silicate (2.65 MR, 1.193 g / mL, heated to 80° C.) and 115 L of water were added to a 1200 L reactor and heated to 85° C. with stirring at 80 RPM and recirculation at 80 L / min. Once 85° C. was reached, sodium silicate (2.65 MR, 1.193 g / ml, heated to 80° C.) and sulfuric acid (1.121 g / mL) were added simultaneously at rates of 4.48 L / min and 1.51 L / min, respectively, over a period of 38 minutes. After the 38 minutes had elapsed, the sodium silicate and sulfuric acid flows were stopped and the reaction mixture was heated to 95° C. Once 95°C was reached, sodium silicate (2.65 MR, 1.193 g / mL, heated to 80°C) was added at 1.73 L / min over an additional 210 minutes, and sulfuric acid (1.121 g / mL) was added at a rate sufficient to maintain a pH of 9.6 (±0.1). After this additional 210 minutes, the sodium silicate flow was stopped and sulfuric acid (1.121 g / mL) was continued at a rate of 0.82 mL / min to adjust the pH to 6.0. Once the pH was stable at 6.0, the batch was filtered, washed to a conductivity of less than 1500 μS, spray dried to a target moisture of 5%, and milled to a particle size of approximately 10 μm.

[0095] Tables 6a and 6b show the analytical values ​​for each example.

[0096] [Table 6]

[0097] [Table 7]

[0098] Example 11: Toothpaste formulation The silica of the present invention described above was formulated into toothpaste and rheology and PCR / RDA measurements were performed. The formulations and results (Table 7a) are shown below. The stannous and fluoride compatibility of the examples according to the present invention is shown in Table 7b.

[0099] [Table 8]

[0100] [Table 9]

[0101] The data in Table 7a show that toothpastes containing silica of the present invention achieve PCR and RDA values ​​within the normal range.

[0102] Stannous compatibility (%) The stannous compatibility of the above samples was determined as follows: A stock solution was prepared containing 431.11 g of 70% sorbitol, 63.62 g of deoxygenated deionized water, 2.27 g of stannous chloride dihydrate, and 3 g of sodium gluconate. 34 g of this stock solution was added to a 50 mL centrifuge tube containing 6 g of the silica sample to be tested. The tube was placed on a wheel rotating at 5 RPM and aged at 40°C for one week. After aging, the tube was centrifuged at 12,000 RPM for 10 minutes and the stannous concentration in the supernatant was measured by ICP-OES (inductively coupled plasma optical emission spectroscopy). Stannous compatibility was determined by expressing the stannous concentration of the sample as a percentage of the stannous concentration of a solution prepared by the same procedure but without the addition of silica.

[0103] Fluoride compatibility (%) The fluoride compatibility of the above samples was determined as follows: A 1624 ppm fluoride stock solution was prepared. 30.0 g of this stock solution was added to a 50 mL centrifuge tube containing 7.0 g of silica sample to be tested. The tube was placed on a wheel (or equivalent stirring means) rotating at 5 RPM and aged at 60°C for 1 hour. After aging, the tube was centrifuged at 12,000 RPM for 10 minutes (or until the supernatant was clear). The fluoride concentration in the supernatant was determined by first taking an aliquot and transferring it to a plastic vial containing a magnetic stir bar and an equal volume of TISAB II buffer. The concentration was then measured using a pre-calibrated fluoride specific ion electrode (Orion model 96-09BN or equivalent). Fluoride compatibility was determined by expressing the fluoride concentration of the sample as a percentage of the fluoride concentration of the stock solution.

[0104] Relative Dentin Abrasion Value (RDA) The RDA values ​​of the dentifrice compositions of Examples DC1-DC14 containing silica of the present invention were determined according to the method described in Hefferen, Journal of Dental Res., July-August 1976, 55 (4), pp. 563-573, and described in U.S. Pat. Nos. 4,340,583, 4,420,312 and 4,421,527 to Wason, the contents of which are incorporated herein by reference in their entireties.

[0105] Pellicle cleaning rate (PCR) The cleaning ability of a dentifrice composition is commonly expressed in terms of a Pellicle Cleaning Rate ("PCR") value. The PCR test measures the ability of a dentifrice composition to remove pellicle film from teeth under certain brushing conditions. The PCR test is described in "In Vitro Removal of Stain with Dentifrice" GK Stookey, et al., J. Dental Res., 61, 12-36-9, 1982. Both PCR and RDA results depend on the nature and concentrations of the components of the dentifrice composition. PCR and RDA values ​​are dimensionless.

[0106] Example 12: Compatibility of CPC and BAC Zeta potential titrations were performed to determine the capacity of a given silica for quaternary ammonium compounds. For the titrations, the desired amount of dry silica was taken and diluted to 160 g with deionized water to prepare the desired 5 wt% suspension of silica. To approximate the desired 5 wt% (8 g) silica in the 160 g suspension, the amount of as-received silica used was adjusted to account for free moisture (loss on drying) and the amount of sodium sulfate present. The suspension was magnetically stirred at 500 rpm for 10 minutes to fully wet the silica, after which the suspension was adjusted to pH ≈8.5 with 0.5 M NaOH or 0.5 M HCl to aid in consistency and more direct comparison of the initial surface chemistry.

[0107] The suspension was then titrated with 0.25 ml increments of 5 wt% cetylpyridinium chloride (CPC) or 5 wt% benzalkonium chloride (BAC) and the capacity of each silica determined by the volume of CPC or BAC required to reach a zeta potential of 0 mV. Since most tests showed artifacts approaching the 0 mV crossover, the capacity was defined as the first point at which the zeta potential became positive. The capacity at this point was then used to determine the mass of CPC or BAC per gram of silica in mg / g.

[0108] Examples 10A, 10B and 10C according to the invention show lower CPC and BAC values ​​and therefore improved CPC / BAC compatibility (Table 8).

[0109] [Table 10]

[0110] [Example 13: Flavor] Method: 500 mg of silica was placed in a headspace vial. 10 μl of flavor (lime oil, lot MKCF9356 flavor matrix) was added and the vial was allowed to equilibrate overnight. Before sampling the headspace, the sample was incubated at 60°C for 60 min with gentle shaking. 1 mL of headspace was analyzed on a GC / MS equipped with a Stabilwax column (0.25 mm x 60 m) with a column flow rate of 1.606 mL / min and a temperature gradient of 6°C / min over the temperature range 40°C to 230°C (HS sampling: 1 ml of headspace was sampled into a gas-tight syringe at 65°C). Peak areas were normalized to the peak intensity of ZEODENT® 113.

[0111] Examples 10A, 10B and 10C according to the invention show higher values ​​and therefore improved flavour compatibility (Table 9).

[0112] [Table 11]

Claims

1. Average primary particle size of over 80 nm, 10 to 40 nm ２ / g BET surface area, a total mercury intrusion volume of 0.75-2.00 cc / g, and an oil absorption of 60-120 cc / 100g.

2. The precipitated silica is 10 to 35 m ２ 2. The precipitated silica of claim 1 having a CTAB surface area of ​​1 / g.

3. 2. The precipitated silica of claim 1, wherein said precipitated silica has a bulk density of 0.40 to 0.80 g / cm 3 .

4. 2. The precipitated silica of claim 1, wherein said precipitated silica has an Einlehner value of less than 18 mg loss / 100 k revolutions.

5. 2. The precipitated silica of claim 1, wherein the precipitated silica has a C content of less than 3%.

6. The precipitated silica has an average primary particle size of more than 90 nm and an average primary particle size of 10 to 26 nm. ２ 2. The precipitated silica of claim 1, having a BET surface area of ​​0.75 to 2.00 cc / 100 g, a total mercury intrusion volume of 0.75 to 2.00 cc / 100 g, and an oil absorption of 60 to 120 cc / 100 g.

7. The precipitated silica has an average primary particle size of more than 80 nm and an average primary particle size of 10 to 30 nm. ２ 2. The precipitated silica of claim 1, having a BET surface area of ​​0.80 to 1.80 cc / 100 g, a total mercury intrusion volume of 0.80 to 1.80 cc / 100 g, and an oil absorption of 70 to 110 cc / 100 g.

8. The precipitated silica has an average primary particle size of more than 90 nm and an average primary particle size of 10 to 26 nm. ２ 2. The precipitated silica of claim 1, having a BET surface area of ​​0.80 to 1.80 cc / 100 g, a total mercury intrusion volume of 0.80 to 1.80 cc / 100 g, and an oil absorption of 70 to 110 cc / 100 g.

9. The precipitated silica has an average primary particle size of more than 100 nm and an average primary particle size of 10 to 23 nm. ２ 2. The precipitated silica of claim 1, having a BET surface area of ​​0.75 to 2.00 cc / 100 g, a total mercury intrusion volume of 0.75 to 2.00 cc / 100 g, and an oil absorption of 60 to 120 cc / 100 g.

10. The precipitated silica has an average primary particle size of more than 80 nm and an average primary particle size of 10 to 30 nm. ２ 2. The precipitated silica of claim 1, having a BET surface area of ​​0.85 to 1.65 cc / 100 g, a total mercury intrusion volume of 0.85 to 1.65 cc / 100 g, and an oil absorption of 60 to 100 cc / 100 g.

11. The precipitated silica has an average primary particle size of more than 100 nm and an average primary particle size of 10 to 23 nm. ２ 2. The precipitated silica of claim 1, having a BET surface area of ​​0.85 to 1.65 cc / 100 g, a total mercury intrusion volume of 0.85 to 1.65 cc / 100 g, and an oil absorption of 60 to 100 cc / 100 g.

12. 1. A method for producing precipitated silica, comprising: (a) continuously feeding an acid and an alkali metal silicate or alkaline earth metal silicate into a liquid medium with stirring at a silicate addition rate V1 and at a temperature of 70-96°C to form silica particles; (b) stopping the supply of alkali metal silicate or alkaline earth metal silicate and acid, and then increasing the temperature to 90-100°C with stirring; (c) adding an alkali metal silicate or alkaline earth metal silicate and an acid with stirring, wherein the silicate addition rate is 1-40% of the silicate addition rate V1 and the acid rate is adjusted to keep the pH value constant at 9.0-10.0 during the addition of the alkali metal silicate or alkaline earth metal silicate; (d) stopping the addition of the alkali metal silicate or alkaline earth metal silicate and adding acid with stirring until the pH is 5.0 to 7.0; A method comprising:

13. (e) filtering the silica of step (d); (f) drying in a spray dryer; 13. A method for producing the precipitated silica of claim 12.

14. 14. The method of claim 13, wherein the silica of step (f) is ground.

15. 13. The method of claim 12, wherein the liquid medium in step (a) is an alkali metal silicate or alkaline earth metal silicate and water.

16. 13. The method for producing precipitated silica according to claim 12, wherein the temperature range of step (a) is from 70 to 95°C.

17. 13. The method for producing precipitated silica according to claim 12, wherein the duration of step (c) is from 100 to 500 minutes.

18. 10. Use of the precipitated silica according to claim 1 in cosmetics, anti-caking flow agents, foods, carrier applications, dentifrices and mouthwashes.

19. A dentifrice composition comprising a precipitated silica according to any one of claims 1 to 11.