Back-Coated Opacifying Label for Wet Condition Durability
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Solution Overview
Problem
Paper labels used in wet applications tend to lose opacity and become fragile, making them unsuitable for conditions involving moisture or humidity, as they deteriorate and become difficult to read.
Innovation Solution
A paper label with a polymeric opacifying layer on its backside, composed of water-dispersible aliphatic polyether-polyurethane and wax, along with optional silica particles, which prevents opacity loss when exposed to moisture, humidity, or wet conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polymeric film or coating is applied to prevent opacity loss, then opacity retention is improved, but the natural appearance of the paper label is lost
Solution Approach 1:
The patent applies a polymeric coating only on the back side of the paper label, leaving the front print surface uncoated and maintaining its natural appearance. This localized application resolves the contradiction by providing opacity retention where needed (back side) while preserving the aesthetic quality where visible (front side).
Solution Approach 2:
The label is divided into two functional zones: the front surface maintains natural paper properties for appearance and printing, while the back surface receives the polymeric coating for moisture resistance and opacity retention. This segmentation allows each surface to optimize its specific function without compromising the other.
2Reliability
If a polymeric film or coating is applied to prevent saturation, then durability in wet conditions is improved, but the label complexity increases
Solution Approach 1:
The polymeric coating is applied selectively only to the back side of the label where moisture exposure occurs, rather than coating the entire label. This reduces the overall material complexity and processing requirements while still providing the necessary durability enhancement.
3Ease of manufacture
If the paper facestock is left uncoated to maintain appearance, then natural look is preserved, but opacity is lost in wet conditions
Solution Approach 1:
The label structure separates the aesthetic function (front surface) from the protective function (back surface). The front remains uncoated for natural appearance while the back receives the polymeric coating to maintain opacity in wet conditions, resolving the contradiction through functional segmentation.
Solution Approach 2:
The polymeric coating acts as an intermediary layer on the back side that prevents moisture penetration to the paper facestock, thereby preserving opacity without interfering with the natural appearance of the front surface.
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
The opacifying layer maintains the label's opacity and durability in wet conditions, ensuring it remains readable and attractive on items like wine bottles even when submerged in water.
Implementation Method 1
an opacifying layer covering the lower surface of the paper substrate, the opacifying layer formed from a coating composition including (a) at least one water-dispersible aliphatic polyether-polyurethane; and (b) at least one wax
Implementation Method 2
The opacifying layer prevents the uncoated paper facestock from losing opacity when the label is subjected to moisture, humidity or wet conditions
Data Source
AI summary
A multilayer label having an opacifying layer coated onto the back side of a paper facestock is provided. The opacifying layer prevents the paper from losing opacity when the label is subjected to wet conditions.