Multi-Ply Paperboard Core Selective Sizing
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Solution Overview
Problem
Existing core stock paper manufacturing processes are limited in incorporating size uniformly across multiple plies, leading to inefficiencies in glue usage and bonding strength, particularly in forming strong and rigid tubes for high-speed rewinders and packaging applications.
Innovation Solution
The method involves forming multi-ply paperboard cores by layering paperboard furnishes where the outermost plies contain no size and adjacent plies contain size, allowing for reduced glue usage while maintaining bonding strength, through a process that includes pressing, calendering, and adhesive application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If size is incorporated uniformly across all plies in multi-ply core stock paper, then bonding strength between plies is improved, but glue absorption efficiency deteriorates and manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by incorporating size only in the inner plies (second and third plies in a four-ply structure) rather than uniformly across all plies. This localized approach provides bonding strength where needed at the ply interfaces while leaving the outer plies free of size to maintain optimal glue absorption characteristics for tube formation.
2Strength
If size is added to all plies in multi-ply paper, then ply bonding is enhanced, but glue usage quantity increases
Solution Approach 1:
The invention reduces glue usage by applying size locally only to inner plies rather than all plies. The outer plies remain free of size, maintaining their natural glue absorption properties and enabling more efficient glue application during tube formation, thereby reducing overall glue consumption.
Solution Approach 2:
The patent segments the multi-ply structure into different functional zones: outer plies without size for optimal glue absorption and tube formation, and inner plies with size for ply bonding. This segmentation allows each layer to perform its specific function efficiently without the compromises of uniform sizing.
3Reliability
If size is incorporated in outer plies, then surface properties are improved, but glue absorption and tube formation efficiency deteriorate
Solution Approach 1:
The patent strategically places size in inner plies rather than outer plies, preserving the outer plies' natural surface properties and glue absorption characteristics. This local differentiation ensures that the outer surfaces remain optimal for glue application and tube formation while inner layers provide necessary bonding.
4Quantity of substance
If multi-ply paper is made with selective sizing, then glue usage is reduced, but manufacturing process complexity increases
Solution Approach 1:
The manufacturing process is segmented into separate furnish preparation streams: one for outer plies without size and another for inner plies with size. This segmentation enables selective sizing that reduces glue usage while maintaining a manageable manufacturing process through organized, modular furnish handling and layering.
Data Source
AI summary
Methods of making a multi-ply paperboard core include providing a number of paperboard furnishes and layering the furnishes to form a multi-ply paperboard web, wherein the two outermost plies are formed of furnish containing no size and the two plies adjacent the outermost plies are formed of furnish containing size. Apparatus for making a multi-ply paperboard core include two or more furnish sources configured to provide a number of paperboard furnishes, wherein at least one furnish source provides furnish containing no size and at least one furnish source provides furnish containing size, and a paperboard forming section wherein the furnishes are layered to form a multi-ply paperboard web in which the two outermost plies are formed of furnish containing no size and the two plies adjacent the two outermost plies are formed of furnish containing size.