Electrostatic Flocking of Rubber Gloves
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Solution Overview
Problem
Existing methods for flocking rubber-based articles, such as gloves, result in a random orientation of fibers, leading to a non-smooth feel and incompatibility with high temperature cure adhesives, which degrade rubber at elevated temperatures, limiting the production of elastic and smoothly flocked rubber-based gloves.
Innovation Solution
The use of precision-cut, perpendicularly oriented synthetic fibers electrostatically applied to a rubber-based article with a low-temperature self-cross-linking elastic adhesive system, ensuring a smooth, silky feel and maintaining elasticity, while avoiding high temperature damage to the rubber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high temperature cure adhesives are used to apply flock to rubber-based articles, then the adhesive bonding strength is improved, but the rubber material degrades at elevated temperatures
Solution Approach 1:
The patent changes the temperature parameter from high temperature (300°F or above) to low temperature (below 200°F) curing process. This parameter change allows the use of heat-curable adhesives without degrading the rubber substrate, as the curing is achieved at temperatures compatible with rubber material stability.
Solution Approach 2:
The patent replaces the thermal curing mechanism with a moisture-curing or chemical-curing mechanism. Instead of relying on high temperature to activate adhesive bonding, the system uses ambient or controlled low-temperature chemical reactions (such as moisture-cured polyurethanes or two-part epoxy systems) to achieve adequate bond strength without thermal degradation of the rubber.
2Ease of manufacture
If conventional pneumatic flock application is used, then the flock can be applied to the article surface, but the fibers are randomly oriented resulting in a non-smooth feel
Solution Approach 1:
The patent replaces the pneumatic (aerodynamic) flock application system with an electrostatic application system. In this system, fibers are charged and attracted to the grounded or oppositely charged article surface, allowing them to orient perpendicular to the surface during application. This electrostatic mechanism provides both application capability and controlled orientation, eliminating the random fiber arrangement problem.
Solution Approach 2:
The patent introduces a new dimension of control by applying electrostatic fields during the flocking process. This additional field dimension enables precise control over fiber orientation and distribution, transforming the random two-dimensional deposition into a controlled process where fibers stand perpendicular to the surface, creating a uniform smooth feel.
3Productivity
If electrostatic flock application is used on a continuous conveyer system, then manufacturing speed is maintained, but the spent flock must be collected and returned through the system
Solution Approach 1:
The patent extracts the spent flock collection function from the main continuous production line. Instead of integrating complex collection and return mechanisms within the conveyer system, the design separates these functions, allowing spent flock to be collected at convenient locations and returned through independent pathways, reducing the complexity of the main production system.
Solution Approach 2:
The patent introduces intermediary collection points and return mechanisms that act as mediators between the electrostatic flocking stations and the main conveyer system. These intermediaries handle the spent flock management, allowing the main production line to maintain continuous operation at high speed without being burdened by the complexity of integrated flock recovery systems.
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 provides a soft, elastic, and smoothly flocked rubber-based article with enhanced moisture absorption and retention of elasticity, achieving a silky feel and improved manufacturing efficiency by using precision-cut fibers and a compatible adhesive system.
Implementation Method 1
An electrostatic applicator is then used to charge synthetic fibers and attract them to the adhesive coated surface of the glove.
Data Source
AI summary
The present invention is directed to an article having at least one surface coated with electrostatically flocked material. The flock material used is one or more fibers, preferably synthetic fibers. When electrostatically flocked onto the article surface, the flock material is oriented, thus providing a silky smooth feel to the surface. The articles may include, for example, elastic articles such as rubber gloves, elastic medical drapes or wraps, elastic orthopedic supports/braces and clothing. The present invention also provides a process and apparatus for electrostatically flocking material onto an article.