Shrink sleeve ink additives must survive printing, seaming and rapid dimensional change on a specific film. Separate substrate wetting from process foam and post-print blocking. Then test the selected route on the actual PETG, PVC, OPS or other film, in the intended print orientation, through the real shrink curve. No additive can correct a binder/film mismatch.
Resin, treatment and shrink curve
Wetting, air and drying
Block, seam, rewind
Image, adhesion and rub
Define the film and print construction
Record film chemistry, gauge, machine/transverse orientation, surface treatment level and age, primer, print side, reverse- or surface-print construction, ink binder, color sequence, white ink, overprint varnish, seam chemistry, rewind tension and storage. PETG, PVC and OPS do not share one shrink curve or solvent tolerance. A candidate must be approved on the purchased film grade, not on a generic plastic panel.
Measure surface treatment before printing and after realistic storage. If treatment decay or contamination causes the wetting failure, adding more surfactant may hide the problem briefly while leaving weak adhesion.
Choose among supported and gated routes
| Route | Public evidence | First-screen use | Boundary |
|---|---|---|---|
| 2100 wetting grade (confirm current brand) | Two live Longchang records use different brand-family names for a similar 2100 wetting grade; confirm the exact product, TDS and COA before using the published dose and system claims | Film wetting, spread and adhesion-related surface entry | Public data do not prove a specific shrink percentage, seam compatibility or post-shrink adhesion |
| CHLUMIAF® 3062 | 100% active defoamer; water/solvent/UV; printing-ink dose 0.1–0.5% | Circulation/grinding foam and air-linked pinholes | Solvent dilution needs stability and performance testing |
| CHLUMIAG® 3501 | 100% active acrylic-modified silicone oil; printing, overprint varnish and release/anti-sticking applications | Only a supplier-supported blocking or release study | No public dose or quantified block/rub result |
Use 2100 for a film-wetting screen
2100 is the better-supported first route when the ink beads, retracts, leaves wetting-related voids or cannot enter a treated packaging film consistently. The public page supports spreading and wetting on polyethylene, polypropylene, polyester and high-smoothness packaging materials, plus waterborne, UV, solvent and high-solids use. It does not specify PETG, PVC or OPS performance, so treat those materials as test variables.
Screen low/mid/high within 0.1–1.0% of total formulation. Keep color strength, viscosity, application volume, drying and treatment level constant. Measure wetting, print density, adhesion before shrink, blocking, seam and post-shrink appearance. Do not select the dose from wetting alone.
Use 3062 only when air is the root cause
3062 is supported as a printing-ink defoamer at 0.1–0.5% total formula and across waterborne, solvent and UV systems. Establish whether foam comes from pigment grinding, pump shear, chamber circulation or transfer. Use a repeatable aeration test and inspect the print for pinholes at equal delivery volume.
If the product is diluted with solvent, its page requires a stability and defoaming test first. Record solvent, dilution ratio, order of addition, shear and aging. Reject a candidate that reduces foam but causes craters, density loss, poor redissolution, intercoat failure or post-shrink cracking.
Keep 3501 out of the first blind trial
3501’s public applications include release and anti-sticking, but the page does not provide a recommended dose or a quantified blocking method. Ask for a current TDS, compatible ink/varnish system, dose and test protocol before screening. First check drying energy, retained solvent or water, rewind temperature, web tension, roll hardness and storage pressure; these frequently drive blocking.
A release improvement may also change coefficient of friction, seam, overprint adhesion or rub. Those downstream effects must be included in the same trial.
Map the shrink window before adding chemistry
ASTM D2732 measures unrestrained linear thermal shrinkage of thin plastic film at selected temperatures. ASTM D2838 addresses shrink tension and orientation release stress. Use the film supplier’s approved curve and production tunnel as the primary specification, while these standards provide disciplined film characterization.
Record shrink in machine and transverse directions, onset temperature, dwell and maximum target shrink. Ink approval must include the full profile, not one convenient temperature. High-shrink areas around shoulders and contours are normally the most revealing.
Run a pre- and post-shrink matrix
| Stage | Controlled variables | Readout | Reject when |
|---|---|---|---|
| Flat print | Film lot, treatment, viscosity, deposit and drying | Wetting, density, pinholes and adhesion | Retraction, voids or weak bond |
| Rewind/age | Tension, temperature, pressure and time | Block, set-off and redissolution | Transfer or surface damage appears |
| Seam | Seam chemistry, width, cure and dwell | Seam integrity and print interference | Additive or ink contaminates the bond zone |
| Shrink ladder | Temperature, dwell, steam/hot-air condition and shrink % | Image, opacity, cracking, adhesion and rub | Failure occurs at any specified profile |
| Filled pack | Container geometry, transport and condensation | Scuff, color transfer and legibility | Graphics fail in realistic distribution |
Test adhesion at the failure locations
Use the converter’s agreed film-ink adhesion method before and after shrink, including the highest-deformation area. Record whether failure is film/ink, ink/ink, ink/white, ink/varnish or cohesive. Tape choice, dwell, removal angle and film support must be fixed. A flat central area can pass while a shoulder or seam area fails.
Measure rub on flat and formed sleeves
ASTM D5264 provides a comparative Sutherland rub practice for printed materials. Agree receptor, load, cycles, conditioning and rating. Add bottle-line and distribution contacts: guide rails, conveyors, adjacent packs, condensation and consumer handling. For reverse print, test the exposed film surface and internal printed construction as appropriate.
Protect seam and overprint compatibility
Keep ink and surface-active additives out of the seam zone when the converting specification requires a clean overlap. Compare seam strength and appearance across the candidate ladder. If an overprint varnish or white backing is used, test intercoat adhesion, trap, drying and blocking as a complete stack. A wetting benefit in the color ink cannot justify failure elsewhere.
Selection rules
- Screen 2100 for a measured film-wetting problem on the exact treated film.
- Screen 3062 for quantified process foam or air-linked pinholes.
- Do not screen 3501 until a dose and blocking/release protocol are supplied.
- Reject any candidate that fails adhesion, rub, seam or image integrity at any required shrink point.
- Fix film treatment, binder compatibility, drying or tunnel conditions before asking an additive to compensate.
Information to send with an inquiry
Provide film resin/grade/gauge, treatment and age, reverse or surface print, ink/white/varnish chemistry, printing process, current additives, application volume, drying, rewind/storage, seam method, shrink curve, container geometry and photographs before and after shrink. Identify whether the root problem is wetting, foam, block, seam, adhesion, rub or image distortion.
Ask Longchang for a shrink sleeve ink test ladder tied to your film and tunnel profile.