Flocked Substrate Injection Molding Without Adhesive
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for producing articles with flocked surfaces, such as 3D flocking, insert molding, and heat-forming, face issues like unpleasant texture, uniformity, reproducibility problems, and high costs due to the need for adhesive fibers that may not withstand injection pressures and temperatures, leading to irreversible crushing and loss of feel.
Innovation Solution
A process where a flocked substrate with temporary adhesive is positioned in an injection mold with fibers oriented inward, allowing them to be embedded in the injected polymer without an additional adhesive, using thermosetting polymers like silicone rubbers and substrates like polyester terephthalate films that can withstand injection conditions, enabling permanent attachment and easy peeling post-injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive fibers are used to attach flock to the injected article, then the flock can be attached to the article surface, but the fibers may not withstand injection pressures and temperatures, leading to irreversible crushing and loss of feel
Solution Approach 1:
The patent removes the adhesive fiber component entirely from the system. Instead of using adhesive-coated fibers that are injected with the polymer, the invention uses a separate flocked substrate that is positioned in the mold before injection. The flock transfers from the substrate to the article surface through the injection process itself, eliminating the need for adhesive fibers that would be subjected to crushing pressures and temperatures.
Solution Approach 2:
The patent introduces a flocked substrate as an intermediary carrier. This substrate holds the flock fibers in place during handling and positioning, then transfers them to the final article surface during injection. The substrate acts as a temporary medium that protects the fibers until they are ready to be applied, avoiding direct exposure to damaging injection conditions during the fiber attachment phase.
2Ease of manufacture
If a flocked substrate is positioned in the injection mold with fibers oriented inward, then the flock fibers can be embedded in the injected polymer without additional adhesive, but the temporary adhesive must withstand high injection temperatures and pressures while allowing subsequent peeling
Solution Approach 1:
The patent changes the thermal and adhesive parameters of the temporary substrate system. The temporary adhesive is specifically selected to have a glass transition temperature below the injection temperature, allowing it to become sufficiently pliable during injection to permit fiber transfer and substrate peeling, while maintaining enough integrity before injection to hold the fibers in place. This parameter optimization enables the dual function of holding and releasing.
Solution Approach 2:
The patent utilizes phase transition behavior of the temporary adhesive material. The adhesive transitions from a rigid, fiber-holding state at room temperature to a pliable, fiber-releasing state during injection due to temperature-induced changes in its physical properties. This phase transition enables the adhesive to perform both holding and releasing functions without requiring separate adhesive applications.
3Ease of manufacture
If traditional flocking processes are used, then articles can be produced with flocked surfaces, but the texture is generally disagreeable and the appearance is uniform and monochromatic with reduced reproducibility
Solution Approach 1:
The patent performs preliminary flocking onto a substrate before the injection molding process. The flock is applied to the substrate in advance under controlled conditions, allowing for consistent density, orientation, and distribution to be achieved before the fibers are subjected to the variable conditions of injection molding. This preliminary action ensures texture quality and appearance consistency are established before the final forming process.
Solution Approach 2:
The patent separates the flocking operation from the injection molding operation. Instead of attempting to do both simultaneously or in sequence with adhesive fibers, the invention divides the process into: (1) flocking the substrate under controlled conditions, (2) positioning the flocked substrate in the mold, and (3) injecting the polymer to transfer and permanently attach the flock. This segmentation allows each process to be optimized independently for quality and consistency.
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 produces articles with enhanced texture and reproducibility, reduces material costs by eliminating the need for separate adhesives, and facilitates recycling by using fibers and polymers from the same material, ensuring durability and ease of recycling.
Implementation Method 1
injection of a polymer being melted in said closed mold through an injection opening
Implementation Method 2
a temporary substrate covered by a temporary adhesive that keeps the flock fibers in place
Implementation Method 3
a thermosetting polymer. Preferably, the temporary adhesive is chosen in the family of silicone rubbers. Such a temporary adhesive makes it possible to obtain attachment sufficient for holding the fibers during production of the injected article, without preventing the subsequent peeling, while resisting conditions of injection temperature and pressure
Implementation Method 4
the temporary substrate is a polyester terephthalate film. Such a temporary substrate allows resistance to conditions of temperature and pressure of injection
Data Source
AI summary
Process for producing an injected article to which a flocked decoration is applied that includes the production of a flocked substrate (11) based on a temporary substrate (1) covered by a temporary adhesive (2) that keeps the flock fibers (3) in place, positioning of the flocked substrate in an injection mold of the article to be produced, injection of a polymer (12) being melted in the closed mold through an injection opening (4), removal of the injected article from the mold and the peeling off of the temporary substrate (1) and the temporary adhesive (2) from the injected article, characterized in that the flocked substrate (11) is positioned in the mold so that the flock fibers (3) are oriented toward the interior of the mold.