Heat-Sealing Barrier Paper Inline Coating Process
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Solution Overview
Problem
Current methods for manufacturing water vapor barrier and heat-sealable papers are costly due to offline processing steps, which limit productivity and increase waste, and existing papers fail to maintain effective barrier properties under tropical conditions.
Innovation Solution
An online manufacturing process for water vapor barrier and heat-sealable paper involves applying a thermoplastic film-forming polymer covering layer with a precoat containing lamellar and finer fillers, allowing for in-line coating and drying, even at high speeds, to achieve low water vapor permeability and heat-sealability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If offline coating and drying processes are used to achieve water vapor barrier and heat-sealable properties, then coating quality and barrier properties are improved, but production cost increases and productivity decreases
Solution Approach 1:
The patent combines the coating and drying operations into a single integrated inline process. The coating head applies the thermoplastic polymer coating while the paper simultaneously passes through a drying section with heating elements, eliminating the need for separate offline coating and drying stages. This integration maintains coating quality while dramatically increasing production speed and reducing costs.
2Ease of operation
If a coating layer of thermoplastic polymer is applied to provide heat-sealable properties, then heat-sealability is achieved, but the coating layer may penetrate too deeply into the fibrous substrate if the paper is not at ambient temperature
Solution Approach 1:
The patent pre-cools the paper substrate to ambient temperature before the coating is applied. This preliminary temperature adjustment prevents excessive penetration of the thermoplastic polymer coating into the fibrous substrate, ensuring proper coating depth and quality while maintaining heat-sealable properties.
3Productivity
If the coating layer is not completely dry before rolling, then the paper can be processed continuously, but the individual turns of the roll will stick together
Solution Approach 1:
The patent integrates the drying function directly into the inline coating process. Heating elements are positioned within the drying section immediately after the coating head, allowing the thermoplastic polymer coating to be completely dried before the paper enters the rolling section. This ensures roll integrity while maintaining continuous high-speed production.
4Reliability
If paper-based composite with barrier properties is manufactured using coating or lamination processes, then water vapor barrier properties are achieved, but production cost becomes expensive
Solution Approach 1:
The patent combines coating, drying, and barrier property achievement into a single integrated inline process. By applying the thermoplastic polymer coating and immediately drying it in-line, the process eliminates multiple separate manufacturing steps, reducing operational costs while achieving reliable water vapor barrier properties of at most 150 g/m2/24h under tropical conditions.
5Productivity
If in-line coating is performed at high paper feed speed, then productivity increases, but the coating layer may not be sufficiently dried before winding
Solution Approach 1:
The patent implements a preliminary drying action within the inline coating process. The drying section with heating elements is positioned immediately after the coating head, providing sufficient drying time and temperature even at high paper feed speeds of 400 m/min or more. This ensures the thermoplastic polymer coating is completely dried before the paper enters the winding section, preventing roll sticking while maintaining high productivity.
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 process reduces production costs, eliminates offline handling, and enhances barrier properties, enabling papers to maintain low water vapor permeability and heat-sealability, suitable for tropical conditions, while increasing manufacturing efficiency.
Implementation Method 1
water vapor barrier properties necessary for the proper preservation of perishable products
Implementation Method 2
The paper is then passed over an infrared heating device, which dries the coating layer
Implementation Method 3
applying a coating layer of a heat-sealable polymer to a cellulosic substrate
Data Source
AI summary
The invention relates to a method for the production of a heat-sealable paper that forms a barrier to water vapour, in particular having a water vapour permeability of at most 150 g/m²/24h measured according to ASTM F1249 under so-called tropical conditions of 38° C and 90% relative humidity, in which at least one coating layer comprising at least one thermoplastic film-forming polymer is applied in-line on the paper-making machine to the fibrous substrate.