Heat treatment of paper products having starch additives

• US 4,919,758 A
• Filed: 09/30/1987
• Issued: 04/24/1990
• Est. Priority Date: 08/23/1985
• Status: Expired due to Fees

• Current Assignee: International Paper Company Purchase New York
• Original Assignee: International Paper Company
• Inventors: Yasnovsky, Vacheslav M., Wagle, Dinkar G.
• Primary Examiner(s): Chin, Peter
• Application Number:
  US07/102,699
• Time in Patent Office: 937 Days
• Field of Search: 162/204, 162/206, 162/207, 162/175, 162/174, 162/135, 162/202, 162/168.1
• US Class Current: 162/175
• CPC Class Codes: D21F 11/00 Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines
• CPC Class Codes: D21H 25/06 of impregnated or coated paper D21H25/08 takes precedence
• CPC Class Codes: D21H 5/129 by thermal treatment

Abstract

A paper product having high stiffness, wet strength, and opacity, and good folding endurance is produced by subjecting a paper web containing a starch additive to high temperature heat treatment.

Claims

1. A method of improving the stiffness and wet strength of a kraft paper product comprising steps of:

incorporating a starch preparation consisting essentially of starch in aqueous solution into the paper product, the amount of starch added being in the range of 0.2% to 10% the weight of the paper product,

adjusting the moisture content of the paper product to within the range of 1% to 20% by weight,

heat treating said paper product at a temperature in the range of 284°

F. to 482°

F. for a period of time in the range of 0.5 to 120 seconds, and then

applying water to the product while the product remains at a temperature above 212°

F., immediately after the heat treating step, to produce a final moisture content in the range of 1% to 20% by weight of the paper product.

2. The method of claim 1 wherein the amount of starch preparation added is in the range of 1 to 3% of the weight of the paper product.