UV-Curable Ink Projections for Decorative Resin Molding
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Solution Overview
Problem
Existing methods for imparting a concave and convex impression on synthetic resin molded articles, particularly on curved surfaces, face challenges such as difficulty in mold extraction and synchronization of color and pattern, leading to suboptimal decorative outcomes.
Innovation Solution
A decorative resin molded article is produced by forming convex projections made of UV-curable resin and colorant on one side of a resin sheet, which are then integrated with a resin injection-molded body using sheet-insert molding, ensuring synchronization of color and concave and convex patterns, even on curved surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If concave and convex patterns are formed on the cavity surface of an injection mold, then the concave and convex pattern can be given to the planar section of the molded article, but the concave and convex pattern cannot be imparted to the side section including curved surface shape parts
Solution Approach 1:
The concave and convex pattern is formed on a resin sheet before injection molding. The patterned resin sheet is then used as a decorative layer in sheet insert molding, allowing the pre-formed pattern to be transferred to the final molded article including curved surfaces without requiring complex mold cavity modifications
Solution Approach 2:
The invention transitions from forming patterns directly on the mold cavity surface (2D mold surface) to forming patterns on a separate resin sheet (independent substrate) that can then be conformally applied to 3D molded articles including curved surfaces, adding a dimensional layer of pattern formation
2Ease of manufacture
If a decorated resin sheet is insert-molded with the decorative layer facing the resin to be injected, then the design can be expressed outside via the resin sheet, but the design is influenced by the transmittance and other properties of the resin sheet
Solution Approach 1:
Instead of placing the decorative layer facing the injected resin (which would be hidden inside), the invention inverts the arrangement by placing the concave and convex patterned surface facing the cavity surface, so the decorative pattern is exposed outward on the final molded article, eliminating dependence on resin sheet transmittance for visual appearance
3Ease of manufacture
If the resin injection-molded body is laminated on the decorative layer, then the decorative layer is provided on the inner face of the resin sheet, but the concave and convex pattern cannot be synchronized with the color pattern
Solution Approach 1:
The invention merges the color pattern and concave and convex pattern formation into a single integrated process by applying both the colorant and forming the relief pattern simultaneously on the resin sheet using inkjet printing with UV-curable ink, ensuring perfect synchronization between color and texture features
Solution Approach 2:
The invention uses a composite ink material containing both colorant and UV-curable resin components. This composite material allows simultaneous deposition of color and formation of convex projections, creating a synchronized color-pattern system that maintains alignment during the injection molding process
4Manufacturing precision
If convex projections are formed using ink containing UV-curable resin and colorant, then the color pattern and concave and convex pattern can be synchronized, but the process requires UV irradiation and inkjet printing equipment
Solution Approach 1:
The invention changes the physical-chemical parameters of the ink material by using UV-curable resin that transitions from liquid to solid upon UV irradiation. This parameter change enables the ink to form stable convex projections with synchronized color patterns, and the curing process integrates seamlessly with the subsequent injection molding operation
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 allows for an excellent concave and convex impression on both planar and curved surfaces, enhancing the decorative appearance and preventing deformation of the convex projections during injection molding.
Implementation Method 1
forming convex projections made of an ink containing a UV-curable resin and a colorant on one side of a resin sheet
Data Source
AI summary
A decorative resin molded article includes a resin sheet having, as formed on one side thereof, convex projections made of an ink containing a UV-curable resin and a colorant, and therefore having, on that one side thereof, a design of a color pattern and a concave and convex pattern synchronizing with each other, and a resin injection-molded body as laminated and integrated on the other side of the resin sheet through injection molding of a synthetic resin thereon.