Cooling Roller Condensate Control for Plastic Film Production
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Solution Overview
Problem
The production of plastic films, particularly battery separator films, often results in defects due to condensate formation when the pre-film is transferred from a slot die to a cooling roller, leading to uneven surface morphology, increased surface roughness, and reduced gloss, which affects the film's quality and functionality.
Innovation Solution
Implementing a cover device, such as a nonwoven fabric or solid cover wall, and/or using a heating element or air circulation/suction devices to prevent condensate formation by maintaining a controlled environment around the cooling roller, ensuring the film solidifies before contact and reducing temperature differences that lead to condensate formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the pre-film is transferred from slot die to cooling roller, then the film solidifies and can be processed further, but condensate forms causing surface defects and reduced quality
Solution Approach 1:
The patent applies preliminary action by pre-heating the cooling roller surface or controlling the temperature gradient before the pre-film contacts the roller. This prevents condensate formation at the contact line by ensuring the roller surface temperature is appropriate before film transfer, thereby avoiding surface defects while maintaining solidification functionality
Solution Approach 2:
The patent changes temperature parameters by controlling the cooling roller temperature, ambient temperature, or film temperature to prevent condensate formation. By optimizing these thermal parameters, the system achieves both film solidification and prevention of harmful condensation effects on surface quality
2Productivity
If cooling roller temperature is reduced to solidify the pre-film, then solidification speed increases, but temperature difference increases leading to more condensate formation
Solution Approach 1:
The patent applies local quality by creating different temperature zones on the cooling roller surface or in the cooling path. The region where the pre-film first contacts the roller is maintained at a higher temperature to prevent condensate, while downstream regions provide stronger cooling for efficient solidification, thus achieving both high productivity and low temperature difference
Solution Approach 2:
The system performs preliminary heating or temperature equalization in the contact region before the pre-film arrives, preventing excessive temperature difference and condensate formation while maintaining overall fast solidification through subsequent cooling zones
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 significantly improves the uniformity and quality of the plastic films by minimizing defects, enhancing their visual appearance and properties, and increasing productivity by reducing the occurrence of condensate-related issues during the film-stretching process.
Implementation Method 1
or the intermediate region between the melt film (5) and the cooling roller (1) is heated such that condensation is not formed or separates no more
Implementation Method 2
a melt or a melt film (5) output from a flat slot die (3), in particular an extruder die, is transferred onto a surface (9') of a cooling roller (1) and cooled by the cooling roller (1)
Implementation Method 3
a blowing device (41) is held at opposing end faces of the cooling roller (1) such that air or a gaseous medium can flow via outlet nozzles (43) at least across the entire width of the melt film (5) and/or at least across the intermediate region (Z)
Implementation Method 4
a suction device (45) is held at opposing end faces of the cooling roller (1) such that air or a gaseous medium can be suctioned via inlet nozzles (47) at least across the entire width of the melt film (5) and/or at least across the intermediate region (Z)
Data Source
AI summary
A method and device for producing a monoaxially or biaxially stretched plastic film are disclosed in which in the intermediate space (Z) tapering in a wedge shape to the contact line between the melt film or plastic film and the roller jacket spaced apart therefrom or the roller surface spaced apart therefrom of the cooling roller, at least one device for preventing precipitation of condensate (K) in the intermediate space (Z) is used and is designed such that precipitation of condensate (a) on the underside of the melt film or plastic film facing the roller jacket (9) or on the roller jacket of the cooling roller is prevented, and/or a condensate (K) which has precipitated there evaporates or vaporises, and/or condensate disposed in the intermediate space is transported away, suctioned off, or blown out and/or runs out to the side.