Multi-Layer Liner Web with Bleached Printing Layer
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Solution Overview
Problem
Current methods for producing printable packaging papers fail to achieve high color density, color brilliance, and contrast while being cost-effective and sustainable, particularly in the production of White Top Kraftliners and Testliners, which compromise on mechanical strength and resource efficiency.
Innovation Solution
A method involving the production of a multi-layer liner web using a bleached fresh pulp as the printing layer and recycled pulp as the carrier layer, with a composition of 20-60% bleached pulp and 40-80% recycled pulp, incorporating multi-stage dewatering and drying, and optional addition of auxiliary substances like starch and sizing agents to enhance printability and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If 100% virgin pulp is used for the printing layer, then print quality and strength are improved, but production costs and environmental impact increase
Solution Approach 1:
The patent applies different pulp qualities to different layers: bleached virgin pulp for the printing layer (where high quality is needed) and unbleached recycled pulp for the carrier layer (where lower quality is acceptable). This local differentiation maintains print quality while reducing overall virgin pulp consumption and production costs.
Solution Approach 2:
The patent creates a composite multi-layer structure combining bleached pulp and unbleached recycled pulp in specific configurations. The printing layer uses bleached pulp for quality, while the carrier layer uses recycled pulp for sustainability, achieving a balance between performance and environmental requirements.
2Quantity of substance
If 100% recycled pulp is used for the printing layer, then sustainability is improved, but mechanical strength and print quality deteriorate
Solution Approach 1:
The patent assigns unbleached recycled pulp specifically to the carrier layer where mechanical strength is less critical for printing, while reserving bleached pulp for the printing layer. This local quality assignment allows high recycled pulp usage (40-80% of total weight) while maintaining adequate mechanical properties.
Solution Approach 2:
The multi-layer composite structure combines the advantages of both bleached and unbleached pulps in appropriate layers, achieving both sustainability goals and mechanical strength requirements through strategic material placement.
3Manufacturing precision
If a smoothing roller is added to improve printability, then surface properties are improved, but machine speed decreases and operating costs increase
Solution Approach 1:
The patent performs surface smoothing and impurity removal during the paper formation process itself, before the paper leaves the paper machine. By integrating these functions into the forming section rather than adding post-processing equipment, the patent maintains high machine speed while achieving good printability.
Solution Approach 2:
The patent combines multiple functions (smoothing, impurity removal, surface preparation) into the paper formation process itself, eliminating the need for separate smoothing roller equipment and maintaining production efficiency.
4Quantity of substance
If the carrier layer is made translucent, then recycled pulp visibility is improved, but print quality deteriorates due to color correction
Solution Approach 1:
The patent makes only the printing layer opaque through bleaching while keeping the carrier layer as unbleached recycled pulp. This local opacity treatment prevents color correction issues in the printing layer while still utilizing recycled fibers in the carrier layer for sustainability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach results in a paper with excellent printability, mechanical robustness, and reduced chemical usage, achieving high-quality print images while minimizing production costs and environmental impact.
Implementation Method 1
multi-stage dewatering/drying of the multi-layer paper web to form a multi-layer liner web
Implementation Method 2
multi-stage dewatering/drying of the multi-layer paper web to form a multi-layer liner web
Implementation Method 3
joining the first paper layer and the second paper layer to form a multi-layer paper web
Data Source
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AI summary
The invention relates to a method for producing a printable, multi-layer liner web (1) for packaging. In the method, a first paper layer (4) is produced from a first pulp (2) comprising a bleached first pulp (3) containing cellulose fibers. A second paper layer (7) is then produced from a second pulp (5) comprising an unbleached second pulp (6) containing cellulose fibers. The first paper layer (4) and the second paper layer (7) are bonded together to form a multi-layer paper web (8) and processed into a multi-layer liner web (1) in a multi-stage dewatering/drying process. The first paper layer (4) forms a printing layer (9), and the second paper layer (7) forms a support layer (10) directly bonded to this printing layer (9).The process stipulates that the first pulp (3) is a bleached, virgin short-fiber material, and the second pulp (6) is a recycled fiber material. The multilayer liner web (1) is produced, based on 100 wt.% of the total mass of the multilayer liner web (1), with 20 wt.% to 60 wt.% of the first pulp (3) and 40 wt.% to 80 wt.% of the second pulp (6).