EP0041056A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Papermaking
Assignee: Nouryon Pulp and Performance Chemicals AB
•
Filing: 1981-05-18
•
Granted: —
•
Expires: 2001-05-18
Abstract
Abstract In making paper from an aqueous papermaking stock, a binder comprising colloidal silicic acid and cationic starch is added to the stock for improving the paper or the retention of the stock components, or is added to the white water for reducing the pollution problems or recovering values from the white water. The cationic starch of the binder has a degree of substitution of not less than 0.01, and the weight ratio of cationic starch to Si0 2 is between 1:1 and 25:1.
Inventors
- 👤 Per Gunnar Bätelson
- 👤 Hans Erik Johansson
- 👤 Hans Magnus Larsson
- 👤 Olof Sundén
- 👤 Per Johan Svending
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 01:35
CPC Classifications
D; D21; D21H; D21H17/00; D21H17/63; D21H17/67; D21H17/68; D21F; D21F1/00; D21F1/66; D21F1/82; D21H17/20; D21H17/21; D21H17/24; D21H17/28; D21H17/29; D21H21/00; D21H21/50; D21H21/52; D21H23/00; D21H23/76; D21H23/765
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
91 words
A papermaking process in which an aqueous papermaking stock containing a cellulosic pulp is formed and dried, characterized by incorporating into the stock prior to the, formation of the sheet a binder comprising colloidal silicic acid, and cationic starch having a degree of substitution of not less than 0.01, preferably from about 0.01 to about 0.05 and most preferably from about 0.02 to about 0.04, the weight ratio of cationic starch to SiO 2 being between 1:1 and 25:1, preferably between 1.5:1 and 10:1, and most preferably between 1.5:1 and 4.5:1.
Claim 2
Dependent Claim
91 words
A papermaking process in which an aqueous papermaking stock containing a cellulosic pulp is formed and dried, characterized by incorporating into the stock prior to the, formation of the sheet a binder comprising colloidal silicic acid, and cationic starch having a degree of substitution of not less than 0.01, preferably from about 0.01 to about 0.05 and most preferably from about 0.02 to about 0.04, the weight ratio of cationic starch to SiO 2 being between 1:1 and 25:1, preferably between 1.5:1 and 10:1, and most preferably between 1.5:1 and 4.5:1.
Claim 3
Dependent Claim
46 words
The process of claim 1,. characterized in that the colloidal silicic acid is provided as a colloidal silicic acid sol having silica particles with a surface area of about 50 to about 1000 m 2 /g, preferably from about 300 to about 700 m 2 /g.
Claim 4
Dependent Claim
23 words
The process of claim 1 or 2, characterized in that the pH of the stock is maintained between about 4 and about 9.
Claim 5
Dependent Claim
26 words
The process of claim 1, 2 or 3, characterized in that the solids in the binder amount to 0.1-15%, preferably 1.0-15% of the weight of pulp.
Claim 6
Dependent Claim
24 words
The process of any one of claims 1-4, characterized in that the aqueous papermaking stock contains a cellulosic pulp and a mineral filler material.
Claim 7
Dependent Claim
32 words
The process of claim 5, characterized in that the amount of cellulosic pulp in the stock is adjusted to give a finished paper containing at least 50% by weight of cellulosic fibers.
Claim 8
Dependent Claim
38 words
The process of claim 5 or 6, characterized in that the solids in the binder amount to from about 0.5 to 25%, preferably from about 2.5 to 15% by weight based upon the weight of the mineral filler.
Claim 9
Dependent Claim
48 words
The process of claim 5, 6 or 7, characterized in that the colloidal silicic acid is added to and mixed with the mineral filler prior to incorporating the mineral filler into the stock and the cationic starch is mixed with the pulp and filler colloidal silicic acid mixture.
Claim 10
Dependent Claim
64 words
The process of any of claims 1 to 7, characterized in intermixing in the stock a portion of the colloidal silicic acid, thereafter intermixing the cationic starch in the stock containing the initial portion of colloidal silicic acid, and, after an agglomerate has formed, adding and intermixing the remainder of the colloidal silicic acid in the stock prior to the formation of the sheet.
Claim 11
Dependent Claim
52 words
The process of claim 9 wherein between about 20 and about 90 percent, preferably between about 30 and about 80 percent of the colloidal silicic acid is added to the stock to form an agglomerate and the remaining portion of the colloidal silicic acid is added after the formation of the agglomerate.
Claim 12
Dependent Claim
103 words
An improved paper product containing cellulosic fibers, preferably in a content of at least 50% by weight of the paper product and characterized by enhanced strength characteristics, wherein the bond between the cellulosic fibers is enhanced by a binder comprising a complex of a colloidal silicic acid and cationic starch having a degree of substitution of not less than 0.01, preferably from about 0.01 to about 0.05 and most preferably from about 0.02 to about 0.04, and wherein the ratio of cationic starch to sio 2 is between 1:1 and 25:1, preferably between 1.5:1 and 10:1, and most preferably between 1.5:1 and 4.5:1.
Claim 13
Dependent Claim
103 words
An improved paper product containing cellulosic fibers, preferably in a content of at least 50% by weight of the paper product and characterized by enhanced strength characteristics, wherein the bond between the cellulosic fibers is enhanced by a binder comprising a complex of a colloidal silicic acid and cationic starch having a degree of substitution of not less than 0.01, preferably from about 0.01 to about 0.05 and most preferably from about 0.02 to about 0.04, and wherein the ratio of cationic starch to sio 2 is between 1:1 and 25:1, preferably between 1.5:1 and 10:1, and most preferably between 1.5:1 and 4.5:1.
Claim 14
Dependent Claim
139 words
A papermaking process in which an aqueous papermaking stock containing cellulosic pulp is formed and dried, characterized in that the white water from the papermaking process is treated with a binder comprising colloidal silicic acid, and cationic starch having a degree of substitution of not less than 0.01, preferably from about 0.01 to about 0.05,and most preferably from about 0.02 to about 0.04, the weight ratio of cationic starch to SiO 2 being between 1:1 and 25:1, preferably between 1.5:1 and 10:1, and most preferably between 1.5:1 and 4.5:1 and the amount of said binder added to the white water for treating same being from about 1 to about 20% by weight, preferably from about 2 to about 10% by weight, based upon the dry weight of solids in the white water and the dry weight of said binder.
Claim 15
Dependent Claim
139 words
A papermaking process in which an aqueous papermaking stock containing cellulosic pulp is formed and dried, characterized in that the white water from the papermaking process is treated with a binder comprising colloidal silicic acid, and cationic starch having a degree of substitution of not less than 0.01, preferably from about 0.01 to about 0.05,and most preferably from about 0.02 to about 0.04, the weight ratio of cationic starch to SiO 2 being between 1:1 and 25:1, preferably between 1.5:1 and 10:1, and most preferably between 1.5:1 and 4.5:1 and the amount of said binder added to the white water for treating same being from about 1 to about 20% by weight, preferably from about 2 to about 10% by weight, based upon the dry weight of solids in the white water and the dry weight of said binder.
Claim 16
Dependent Claim
33 words
A papermaking process in which an aqueous papermaking stock containing a cellulosic pulp is formed and dried, to be performed substantially as hereinbefore described and claimed with particular reference to the accompanying drawings.
Claim 17
Dependent Claim
20 words
An improved paper product containing cellulosic fibers, substantially as hereinbefore described and claimed with particular reference to the accompanying drawings.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.