Multilayer Propylene Facestock for Label Conformability
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Solution Overview
Problem
Current label facestocks are not environmentally friendly and lack adequate properties for labeling applications, such as conformability and mechanical strength, which are essential for efficient labeling and printing processes.
Innovation Solution
A machine direction oriented multilayer facestock is developed, comprising a core layer with propylene homopolymer, low density polyethylene, hydrocarbon resin, and styrene block copolymer, with skin layers made of propylene homopolymer and linear low density polyethylene, and an adhesive layer, optimized for stretching and printing, to provide enhanced mechanical properties and environmental sustainability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional label facestocks are used, then manufacturing simplicity is maintained, but environmental friendliness and adequate mechanical properties are insufficient
Solution Approach 1:
The patent employs a multilayer composite structure consisting of a core layer and skin layers with specific polymer compositions. The core layer contains propylene homopolymer, low density polyethylene, hydrocarbon resin, and styrene block copolymer, while skin layers contain propylene homopolymer and linear low density polyethylene. This composite structure provides enhanced mechanical strength, conformability, and environmental sustainability compared to conventional single-layer facestocks.
Solution Approach 2:
The facestock is divided into distinct functional layers: a core layer providing structural integrity and mechanical properties, and skin layers providing surface functionality for printing and adhesive bonding. This segmentation allows each layer to be optimized for its specific function, with the core layer containing 40-90% propylene homopolymer for strength and the skin layers containing 30-80% propylene homopolymer for surface performance.
2Strength
If the facestock is stretched in machine direction by a high stretch ratio, then mechanical strength and conformability are improved, but manufacturing complexity increases
Solution Approach 1:
The patent specifies a machine direction stretch ratio of 4:1 to 8:1 as an optimal parameter range that achieves the desired mechanical strength and conformability. The core layer contains 40-90% propylene homopolymer and the skin layers contain 30-80% propylene homopolymer, with these compositional parameters working together with the stretch ratio to produce the required mechanical properties without excessive manufacturing complexity.
3Reliability
If the facestock composition is optimized for mechanical properties, then labeling performance is improved, but printability may be affected
Solution Approach 1:
The patent creates different local compositions within the multilayer structure to satisfy different functional requirements. The skin layers contain 30-80% propylene homopolymer and 10-50% linear low density polyethylene to provide good printability and surface properties, while the core layer contains 40-90% propylene homopolymer with additional polymers and resins to provide mechanical strength. This local quality differentiation ensures both printability and labeling performance are optimized.
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 solution offers a conformable, mechanically strong, and environmentally friendly label facestock that reduces haze after printing, supports efficient labeling, and maintains printability, while being cost-effective and suitable for various labeling applications.
Implementation Method 1
stretching the facestock in machine direction by a longitudinal force by a first roll and a second roll at a stretch ratio of 4:1 to 8:1
Data Source
Figure 1a~1c
Figure 1d~1e
Figure 1f
AI summary
The invention relates to a machine direction oriented multilayer facestock (100) of a label and a label, wherein the facestock (100) comprises a core layer (101) and a first skin layer(110). The core layer (101) comprises propylene homopolymer, low density polyethylene, hydrocarbon resin and styrene block copolymer. The invention also relates to use of the facestock (100) for self-adhesive labels. The invention further relates to a method for manufacturing the facestock(100).