Stretch Laminate TEM Film Relaxation and Bonding
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Solution Overview
Problem
The existing methods for manufacturing elastic laminates using Thermoplastic Elastomeric Material (TEM) films bonded to non-woven webs do not achieve the desired level of retraction upon stress removal, limiting the elasticity and flexibility of the laminate.
Innovation Solution
A method involving the extrusion of TEM film onto a carrier web, stretching in the machine direction, and subsequent relaxation for a predetermined time before bonding with envelope webs, allowing for controlled tension winding to form the elastic laminate, which enhances retraction and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the TEM film is stretched in machine direction to achieve flexibility and elasticity, then the laminate gains elastic properties, but the film exhibits neck-down effect and does not fully retract to original dimensions
Solution Approach 1:
The patent applies preliminary stretching to the TEM film before bonding to the nonwoven webs. By pre-stretching the film to a controlled elongation (e.g., 5-50%) and then bonding it to the envelope webs in this stretched state, the film's elastic properties are enhanced while the envelope webs constrain the film's retraction, preventing excessive neck-down and maintaining dimensional stability during subsequent processing and use.
2Ease of operation
If the TEM film is stretched to increase flexibility, then the laminate becomes more flexible, but the retraction speed and extent are limited
Solution Approach 1:
The patent creates a composite laminate structure by bonding the stretched TEM film between two nonwoven envelope webs. This composite structure combines the elastic properties of the TEM film with the structural support and constraint of the envelope webs, achieving enhanced flexibility while the envelope webs prevent excessive deformation and control the retraction behavior, thereby maintaining both flexibility and retraction performance.
3Adaptability or versatility
If the TEM film is stretched to achieve desired elastic behavior, then the laminate gains stretch properties, but permanent set elongation remains
Solution Approach 1:
The patent applies preliminary stretching to the TEM film before bonding to establish the desired elastic behavior. By controlling the pre-stretch amount and bonding the film in this state to constrained envelope webs, the laminate achieves the required stretch properties while the envelope webs limit excessive retraction, thereby reducing permanent set and improving dimensional stability over time.
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 method ensures the elastic laminate achieves the desired elasticity and flexibility by allowing the TEM film to relax and retract fully, mitigating neck-down effects and improving the laminate's properties during further processing.
Implementation Method 1
stretching the delaminated TEM layer in its machine direction in a stretching station via a plurality of web guide means
Implementation Method 2
the elastic laminate may upon release of mechanical stress or strain quickly retract to a certain degree
Implementation Method 3
storing the unstretched second laminate in a second storage for at least 6 hours... allowing the TEM film to relax and retract fully
Data Source
AI summary
A method to manufacture an elastic laminate is disclosed. Thermoplastic Elastomeric Material (TEM) is selected from a polymer supply and fed into an extruder. The TEM film is extruded by the extruder by passing the TEM polymer through an extrusion die head to form a TEM film layer on a carrier web provided by a carrier supply. The TEM film layer is allowed to solidify on the carrier web, thereby forming a first laminate. The first laminate is stored in a first storage prior to being delivered to a delamination unit, which delaminates the first laminate by separating the TEM layer from the carrier web. The delaminated TEM layer is stretched at least in its Machine Direction (MD) in a stretching station via a plurality of web guide means. The stretched TEM layer is positioned between a first envelope web and optionally a second envelope web prior to being delivered to a bonding unit, which connects them to form a second bonded laminate. The second bonded laminate is unstretched and stored in a second storage for a predetermined time. The stored second bonded laminate is wound under controlled tension to form a roll or spool, thereby forming the elastic laminate.