Transparent PET Underlay with Stripe-Coated Adhesive for Flexographic Plates
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Solution Overview
Problem
The mounting of flexographic printing plates onto printing press carriers using double-sided adhesive tapes often results in trapped air bubbles, leading to inefficiencies and image distortion during printing.
Innovation Solution
A double-sided adhesive flexographic printing plate underlay featuring a glass clear PET carrier sheet coated with transparent solvent acrylic adhesive, where the adhesive is stripe-coated with 0.9-1.1mm gaps between stripes, creating air channels to prevent trapped air and ensuring consistent adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If double-sided adhesive sticky tape is used to mount the flexographic printing plate to the carrier, then the plate can be securely attached, but air bubbles tend to get trapped between the adhesive and the surface, leading to mounting difficulties and image distortion
Solution Approach 1:
The adhesive layer incorporates a microporous structure with controlled porosity (3-15% open cell structure) that allows air bubbles to escape through the adhesive during mounting, preventing trapped air while maintaining secure attachment. The pores act as air channels that facilitate air removal without compromising the adhesive's bonding strength.
Solution Approach 2:
The adhesive comprises a composite formulation combining acrylic polymer base resin with specific additives including porogens (such as hollow glass microspheres or foam beads) that create the microporous structure. This composite material provides both strong adhesion properties and air permeability, resolving the contradiction between secure attachment and ease of mounting.
2Manufacturing precision
If a solid photopolymer is used to achieve high definition images, then image quality is improved, but the photopolymer requires harsh solvent-based washout procedures that can cause warping and image distortion
Solution Approach 1:
The microporous adhesive layer is applied to the back of the photopolymer plate before the washout process, serving as a cushioning layer that absorbs and distributes the stress from solvent exposure. This pre-applied adhesive layer prevents warping during the harsh washout procedure while allowing the high definition image to be maintained.
Solution Approach 2:
The microporous structure of the adhesive allows solvent-based washout chemicals to pass through uniformly across the plate, preventing localized pooling and uneven chemical exposure that causes warping. The porous network distributes the solvent flow evenly, maintaining plate stability during the washout process while still enabling effective removal of uncured photopolymer.
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 underlay effectively reduces air bubble trapping and minimizes image distortion by ensuring consistent adhesion and preventing warping of the flexographic printing plate, while also surviving harsh solvent-based washout procedures.
Implementation Method 1
a glass clear polyethylene terephthalate (PET) carrier sheet coated on a front side and a back side thereof with a transparent solvent acrylic adhesive... a glass clear polyethylene terephthalate (PET) release liner adhered to the front side of the carrier sheet by way of the solvent acrylic adhesive stripe-coating
Implementation Method 2
the adhesive is stripe-coated such that each adhesive stripe is separated from its neighbours by a 0.9-1.1mm gap of non-coated sheet... these gaps act as air channels that facilitate the ejection of air from between the flexographic printing plate
Implementation Method 3
The combination of the transparent solvent acrylic adhesive and the glass clear PET carrier sheet and release liner renders the underlay of the present invention transparent to UV light
Data Source
Figure 1
Figure 2~3
AI summary
The present invention provides a double-sided adhesive flexographic printing plate underlay for use in the manufacture and mounting of flexographic printing plates. The underlay is carrier sheet with a solvent acrylic adhesive stripe-coating provided on both sides thereof. In addition, a siliconized release liner is provided to cover one of the coated sides of the carrier sheet. Both the carrier sheet and the release liner are formed from a glass clear polyethylene terephthalate (PET) and the solvent acrylic adhesive is transparent such that ultraviolent light can readily pass through the underlay. The construction of the underlay is such that it can withstand the washout conditions employed in the manufacture of both liquid and solid photopolymer flexographic printing plates.