US3915734A — Modified precipitated alumino silicate pigments a…

Claim 1

Independent Claim 136 words

A METHOD FOR PRODUCING FINELY-DIVIDED PRECIPITATED ALUMINO-SILICATE PARTICULATES SAID METHOD COMPRISING THE STEPS OF INTRODUCING DILUTE AQUEOUS SOLUTIONS OF AN ALKALI SILICATE AND A WATER SOLUBLE ACID SALT OF ALUMINUM INTO AN AGITATED AQUEOUS RECEIVING MEDIUM CONTAINING AN ALKALINE EARTH SALT OR HYDROXIDE AND SODIUM SULFATE SAID SULFATE BEING PRESENT IN AN AMOUNT WITHIN THE RANGE OF FROM ABOUT 2 TO 15% BY WEIGHT, BASED ON THE WEIGHT OF THE WATER FORMING SAID AQUEOUS REACTION MEDIUM MAINTAINING THE RESULTING REACTION MASS AT A PH IN THE RANGE OF ABOUT 8 TO 12 DURING THE REACTION TO THEREBY PRODUCE IN SAID FLUID REACTION MEDIUM VERY FINE WHITE PRECIPITATE PARTICULATES COMPOSED PRINCIPALLY OF OXIDES OF AN ALKLINE EARTH METAL AN ALKALI METAL ALUMINUM AND SILICON SAID FINELY DIVIDED PRECIPITATED PARTICULATES ALL BEING LESS THAN 1 MICRON IN DIAMETER.

Claim 2

Independent Claim 136 words

A METHOD FOR PRODUCING FINELY-DIVIDED PRECIPITATED ALUMINO-SILICATE PARTICULATES SAID METHOD COMPRISING THE STEPS OF INTRODUCING DILUTE AQUEOUS SOLUTIONS OF AN ALKALI SILICATE AND A WATER SOLUBLE ACID SALT OF ALUMINUM INTO AN AGITATED AQUEOUS RECEIVING MEDIUM CONTAINING AN ALKALINE EARTH SALT OR HYDROXIDE AND SODIUM SULFATE SAID SULFATE BEING PRESENT IN AN AMOUNT WITHIN THE RANGE OF FROM ABOUT 2 TO 15% BY WEIGHT, BASED ON THE WEIGHT OF THE WATER FORMING SAID AQUEOUS REACTION MEDIUM MAINTAINING THE RESULTING REACTION MASS AT A PH IN THE RANGE OF ABOUT 8 TO 12 DURING THE REACTION TO THEREBY PRODUCE IN SAID FLUID REACTION MEDIUM VERY FINE WHITE PRECIPITATE PARTICULATES COMPOSED PRINCIPALLY OF OXIDES OF AN ALKLINE EARTH METAL AN ALKALI METAL ALUMINUM AND SILICON SAID FINELY DIVIDED PRECIPITATED PARTICULATES ALL BEING LESS THAN 1 MICRON IN DIAMETER.

Claim 3

Dependent Claim 73 words

The method in accordance with claim 1 wherein the initial volume of said aqueous receiving medium is at least half the combined volume of said solutions of the alkali metal silicate and the aluminum salt and wherein said alkaline earth salt or hydroxide is present in said receiving medium in an amount such that the alkaline earth metal comprises from about 0.1 to 8.0% based on the dry weight of the precipitated particulate.

Claim 4

Dependent Claim 95 words

The method in accordance with claim 1 wherein the aqueous reaction mass is maintained at a pH in the range of about 8 to 12 while combining said solutions of the alkali silicate and the aluminum salt; said method further comprising reducing the pH of the fluid reaction medium to a pH of between about 8 to 9.5 at the end of the reaction period and thereafter further reducing the pH of the reaction medium by the addition of an excess of said aluminum salt to from about 5-6 to thereby obtain a neutral pigment.

Claim 5

Dependent Claim 22 words

The method in accordance with claim 1 wherein the alkaline earth salt is a water soluble salt of calcium, magnesium, or barium.

Claim 6

Dependent Claim 24 words

The method in accordance with claim 1 wherein said aluminum salt includes a finely divided precipitated silica suspended in an aqueous dilute solution thereof.

Claim 7

Independent Claim 269 words

A method for producing finely-divided, precipitated alkaline earth alkali metal alumino-silicates having particular utility for use in paper, said method comprising the steps of introducing a dilute aqueous solution of an alkali silicate selected from the group consisting of sodium and potassium silicates into an agitated aqueous receiving medium containing an alkaline earth salt selected from the group consisting of the water soluble salts of magnesium, calcium, and barium or mixtures thereof and as a promoter or catalyst, sodium sulfate; said sulfate being present in an amount within the range of from about 2 to 15% by weight, based on the weight of the water forming said aqueous receiving medium; continuing the addition of said alkali silicate to said receiving medium until the pH of said receiving medium is at least 8 and for a period of time to effect an initial reaction between said alkali silicate and said alkaline earth salt; introducing a dilute solution of a water soluble acid salt of aluminum into said receiving medium while continuing the addition of said alkali silicate; said simultaneous addition of the alkali silicate and aluminum salt being controlled such that the pH of the fluid reaction medium is in the range of 8 to 12 to thereby produce in said medium a very fine white precipitated particulates composed principally of oxides of said alkaline earth metal, said alkali metal, aluminum and silicon; adjusting the pH of the fluid reaction medium to between about 8 to 10, and separating, drying, and disintegrating said precipitates to obtain a pigment having a particle size of not greater than 1 micron in diameter.

Claim 8

Independent Claim 269 words

A method for producing finely-divided, precipitated alkaline earth alkali metal alumino-silicates having particular utility for use in paper, said method comprising the steps of introducing a dilute aqueous solution of an alkali silicate selected from the group consisting of sodium and potassium silicates into an agitated aqueous receiving medium containing an alkaline earth salt selected from the group consisting of the water soluble salts of magnesium, calcium, and barium or mixtures thereof and as a promoter or catalyst, sodium sulfate; said sulfate being present in an amount within the range of from about 2 to 15% by weight, based on the weight of the water forming said aqueous receiving medium; continuing the addition of said alkali silicate to said receiving medium until the pH of said receiving medium is at least 8 and for a period of time to effect an initial reaction between said alkali silicate and said alkaline earth salt; introducing a dilute solution of a water soluble acid salt of aluminum into said receiving medium while continuing the addition of said alkali silicate; said simultaneous addition of the alkali silicate and aluminum salt being controlled such that the pH of the fluid reaction medium is in the range of 8 to 12 to thereby produce in said medium a very fine white precipitated particulates composed principally of oxides of said alkaline earth metal, said alkali metal, aluminum and silicon; adjusting the pH of the fluid reaction medium to between about 8 to 10, and separating, drying, and disintegrating said precipitates to obtain a pigment having a particle size of not greater than 1 micron in diameter.

Claim 9

Dependent Claim 22 words

The method in accordance with claim 6 wherein said dilute solution of the aluminum salt includes finely divided precipitated silica suspended therein.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1978-10-27	1979-04-28	1979-10-28	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1982-10-27	1983-04-28	1983-10-28	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1986-10-27	1987-04-28	1987-10-28	$7700.00	Window Closed / Lapsed

Modified precipitated alumino silicate pigments and method for preparing same

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