Claims
- 1. A method for sizing paper products comprising the steps of
- (a) providing a paper stock system;
- (b) forming, in the absence of high shearing forces and under normal pressures, a sizing emulsion consisting essentially of from 85 to 99 parts of a substituted cyclic dicarboxylic acid anhydride containing hydrophobic substitution; from 1 to 15 parts of an ethoxylated castor oil containing at least 5 moles ethylene oxide per mole castor oil; and water;
- (c) forming a web from the paper stock system;
- (d) dispersing said emulsion within the paper stock either before or after formation of said web but prior to passing said web through the drying stage of the paper making operation in an amount sufficient to provide a concentration of the substituted cyclic dicarboxylic acid anhydride of from 0.01 to 2.0%, based on dry fiber weight.
- 2. The method of claim 1, wherein the sizing emulsion is formed in situ within the paper stock system.
- 3. The method of claim 1, wherein the sizing emulsion is formed prior to introduction into the paper stock system.
- 4. The method of claim 3, wherein the size mixture is emulsified with water in a sufficient quantity to yield an emulsion containing the substituted cyclic dicarboxylic acid anhydride in a concentration of from 0.1 to 20%, by weight of the total emulsion, prior to addition to the paper stock system.
- 5. The method of claim 4 wherein the size mixture is emulsified in an aqueous dispersion of a cationic or amphoteric retention agent.
- 6. The method of claim 3, wherein the size mixture in the form of an aqueous emulsion is sprayed onto the formed web prior to the drying operation.
- 7. The method of claim 1, wherein there is dispersed within the paper stock prior to the conversion of the paper stock into a dry web, at least 0.01% based on dry fiber weight, of a cationic retention agent.
- 8. The method of claim 1 wherein the cyclic dicarboxylic acid anhydride is represented by the formula: ##STR5## wherein R represents a dimethylene or trimethylene radical and wherein R' is a hydrophobic group containing more than 4 carbon atoms which may be selected from the class consisting of alkyl, alkenyl, aralkyl, or aralkenyl groups.
- 9. The method of claim 8 wherein the cyclic dicarboxylic acid anhydride is selected from the group consisting of: ##STR6## wherein R.sub.x is an alkyl radical containing at least 4 carbon atoms and R.sub.y is an alkyl radical containing at least 4 carbon atoms, and R.sub.x and R.sub.y are interchangeable; ##STR7## wherein R.sub.x is an alkyl radical containing at least 4 carbon atoms and R.sub.y is an alkyl radical containing at least 4 carbon atoms and R.sub.x and R.sub.y are interchangeable.
- 10. The method of claim 1 wherein the ethoxylated castor oil contains 25 to 200 moles ethylene oxide per mole castor oil.
- 11. The method of claim 1 wherein wherein the ethoxylated castor oil is present in an amount less than 10 parts by weight of the mixture.
- 12. Paper or paperboard prepared by the method of claim 1.
- 13. Paper or paperboard prepared by the method of claim 2.
Parent Case Info
This application is a division of application Ser. No. 049,032, filed Apr. 27, 1987, now U.S. Pat. No. 4,728,366, which is a continuation of application Ser. No. 783,903 filed Oct. 3,1985, now abandoned,
US Referenced Citations (10)
Non-Patent Literature Citations (1)
Entry |
Chem. Abst., 92:24660r. |
Divisions (1)
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Number |
Date |
Country |
Parent |
49032 |
Apr 1987 |
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Continuations (1)
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Number |
Date |
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Parent |
783903 |
Oct 1985 |
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