Erasable Writable Surface with Low-Energy Superstrate
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Solution Overview
Problem
Erasable writable materials and films are susceptible to staining and ghosting when used with permanent and non-permanent marking substances, especially over extended periods, limiting their durability and appearance in large format applications.
Innovation Solution
The development of an improved erasable writable material featuring a flexible vinyl or polyvinylchloride substrate with an etched receiver surface and a transparent polyester film, incorporating a superstrate with reduced surface energy and increased hardness, along with a pressure and heat-activated adhesive system, to enhance graphic element adherence and prevent staining and ghosting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional erasable writable materials are used with permanent and non-permanent marking substances, then the material can be written upon and erased, but the material becomes susceptible to staining and ghosting over extended periods
Solution Approach 1:
The patent applies parameter changes by modifying the surface energy of the polyester film through the superstrate coating. The superstrate reduces surface energy to approximately 15-30 mN/m, which prevents marking substances from adhering to the surface, thereby eliminating staining and ghosting while maintaining the film's erasable writable functionality over extended periods
Solution Approach 2:
The patent uses a composite material structure consisting of a polyester film substrate combined with a superstrate coating layer. This composite provides both the mechanical properties of the polyester film (flexibility, durability) and the surface properties of the superstrate (low surface energy, stain resistance), resolving the contradiction between erasability and stain resistance
2Reliability
If the marking side surface energy is reduced to prevent staining, then resistance to marking substances improves, but graphic element adherence may be compromised
Solution Approach 1:
The patent applies local quality by creating different surface energy characteristics on different sides of the polyester film. The marking side has reduced surface energy (15-30 mN/m) to prevent staining, while the seal side maintains high surface energy (>45 mN/m) for strong adhesive bonding of graphic elements, thus resolving the contradiction between stain resistance and graphic adherence
3Strength
If the polyester film hardness is increased to improve durability, then resistance to marking substances improves, but the film may become less flexible
Solution Approach 1:
The patent applies parameter changes by increasing the durometer hardness of the polyester film marking side to exceed Shore D 79 (and preferably exceed Shore D 90) while maintaining the film's flexibility through controlled thickness (approximately 50 microns). This resolves the contradiction between hardness for durability and flexibility for adaptability
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 effectively prevents staining and ghosting, ensuring improved resilience and longevity of the material, even when exposed to marking substances for extended periods, while maintaining high optical clarity and durability.
Implementation Method 1
The receiver surface is configured, treated, and/or adjusted to be etched or micro-etched and to increase a surface energy thereof to exceed about 38 to about 45 millinewtons per meter (mN/m), which improves the surface receptivity and capability to receive, mount, adhere, and/or carry printable, printed, and preformed graphic elements
Implementation Method 2
The seal side includes and/or may include an adhesive and is and/or may treated, adjusted, and/or configured to have a surface energy that exceeds approximately or about 45 millinewtons per meter (mN/m)... The adhesive applied to the seal side to also be at least one of heat and pressure activated, which enables lamination and joining to the receiver surface utilizing one or more of a predetermined heat, pressure, and rolling lamination speed
Implementation Method 3
The superstrate is applied to the marking side of the polyester and/or PET film, and when so applied lowers a surface energy of the marking side to be approximately between 15 and 30 mN/m, and/or below about 24 mN/m... configured, selected, adjusted, modified, and/or formulated to have a maximum optical light transmission and minimum optical haze
Implementation Method 4
The superstrate includes at least one of and/or one or more of a perfluoropolyether, a polyurethane, an acrylated polyurethane, and/or an acrylate resin that is hardenable and/or may be hardened, as well as a photoinitiator that is responsive to ultraviolet radiation to enable curing and hardening of the superstrate after application
Data Source
AI summary
An erasable writable material for large format applications is disclosed, and includes a cast polyvinylchloride film with a mount surface opposite an etched receiver surface. Also incorporated is a transparent polyester film that has a marking side with a hardness exceeding approximately shore D 79 and an opposite seal side, hermetically laminated to the receiver surface. The marking side includes a clear superstrate that has a hardness exceeding approximately shore D 90, which is applied to the marking side of the polyester film to lower surface energy below about 24 millinewtons per meter. The receiver surface is treated to have a surface energy exceeding about 45 millinewtons per meter, to enable improved adherence of printed and preformed graphic elements, which are encapsulated when laminated between the PET film and receiver surface. The superstrate includes a perfluoropolyether, a polyurethane, an acrylated polyurethane, and/or an acrylate resin to harden the material.