MATERIAL SELECTION GUIDE
Product Performance & Suitable Substrates
Start with the substrate, then compare performance. Explore applications, indicative resistance and process requirements for organic low-temperature waterslide decal inks, direct-to-glass inks and water-soluble glass coatings.
How to use these figures
The immersion times below are conservative average reference values drawn from our laboratory and market experience. They are not guaranteed results for every substrate and process combination, nor a statement of certification or compliance with a particular test standard. Agree on test conditions and acceptance criteria before sampling, then validate the specific material and complete decoration system.
The same ink can behave differently on different surfaces
Adhesion must be discussed in relation to the actual surface. The substrate, any existing coating and the final curing conditions all affect the finished decoration.
Bare glass
Room-temperature water immersion performance of organic low-temperature waterslide decals on bare glass can be inconsistent. Do not assume that results on coated glass also apply. Direct-to-glass inks use a separate curing system.
Coated glass
In general, applying decals or directly printing glass inks onto glass bottles with an existing surface coating greatly improves adhesion. However, some coatings lack recoatability; these surfaces can be more difficult to work with than uncoated clear glass bottles.
Ceramic & metal
Adhesion can usually be achieved on ceramic and metal, but commercial applications are uncommon. Metal products typically do not use such a costly decoration process. Ceramics are mostly used for durable tableware and therefore generally use high-temperature fired decals. A small number of spirits bottles are made of ceramic, but these are also usually spray-coated for colour.
Plastic
Most plastics cannot withstand baking at temperatures above 80°C, which prevents the decals from curing fully. We therefore recommend using air-drying waterslide decal inks. Alternatively, we can spray a layer of clear air-drying varnish directly over the decals.
Organic Low-Temperature waterslide decal inks
The design is printed on decal paper and then transferred to the substrate. UV LED curing takes place during printing; it does not replace the final bake after application. For suitable glass, ceramic and metal systems: a reference bake of 160°C for 30 minutes. For plastics, we recommend air-drying waterslide decal inks, or spraying a layer of clear air-drying varnish over the decals.
“52% ABV spirits” means spirits with approximately 52% alcohol by volume. These results should not be assumed to apply to all industrial alcohols or other solvents.
| Material | Immersion in 52% ABV spirits | Room-temperature tap-water immersion | Selection & process notes |
|---|---|---|---|
| Solvent-based clear varnish | Over 3 hours | Over 4 hours | An environmentally friendly ink. Solvent-based waterslide decal inks generally provide more consistent adhesion and appearance; for example, they are less prone to yellowing at high temperatures. The drawbacks are lower production efficiency and higher VOC emissions from organic solvents. They are a very suitable choice when high output is not a priority. |
| UV LED clear varnish | Over 1 hour | Over 2 hours | Contains BPA. Suitable for high-volume spirits and perfume bottle decals. Hard and soft versions allow hardness adjustment for climate and process conditions; does not corrode the underlying ink layer. Suitable for projects that prioritise high output, high gloss and high transparency. |
| UV LED clear relief varnish | Over 3 hours | Over 1 hour | Contains BPA. It can be printed in very thick layers, creating an uneven, raised texture that can be felt by hand and a more pronounced three-dimensional appearance. The drawback is that increasing the thickness inevitably makes yellowing more likely. The effect needs to be evaluated when applied over white. |
| UV LED decal hot-stamping primer | No separate resistance target | No separate resistance target | Available in BPA-containing and BPA-free versions. Primarily used with metallised hot-stamping foil to create a metallic effect. It provides initial adhesion only, without resistance properties, and therefore needs a protective varnish. |
| Solvent-based / UV LED colour inks | Confirm by colour and system | Confirm by colour and system | Solvent-based colour inks are environmentally friendly, while UV LED colour inks contain BPA. Common colours such as black, white and red are available. Solvent-based colour inks offer higher colour strength. For dark colours, UV LED inks have noticeably lower colour strength than solvent-based inks, so we recommend solvent-based colour inks. |
Direct-to-glass inks
These inks are printed directly onto glass, without a decal transfer. The current direct-print series uses UV LED curing, followed by a reference final bake of 160°C for 30 minutes.
| Material | Immersion in 52% ABV spirits | Room-temperature tap-water immersion | Selection & process notes |
|---|---|---|---|
| Glass hot-stamping primer | Over 6 hours | Over 6 hours | Contains BPA. Pair with a suitable foil; reference hot-stamping temperature: 160–180°C, to be confirmed for the foil and equipment. |
| Direct-to-glass clear varnish | Over 6 hours | Over 6 hours | Contains BPA. Can be used with colour inks to adjust colour concentration. |
| Direct-to-glass colour inks | Over 2 hours | Over 2 hours | Contains BPA. Black, white, red, yellow and other common colours are available. Pigment type and loading affect resistance; confirm each colour. |
Direct-to-glass systems typically use more reactive curing agents. Mix the amount needed shortly before use to reduce leftover material. Their curing mechanism differs from waterslide systems, so resistance figures should not be transferred between the two.
Water-soluble glass coatings
For spray coating glass surfaces. Established options include clear, opaque-colour and transparent-colour coatings, with colour matching or custom formulations available for project requirements.
Suitable substrates
Glass bottles, flat glass, and glass packaging for perfume, cosmetics and spirits. Provide the actual glass and information on any existing surface treatment.
Dilution & curing
Only water is needed as the diluent. Water-soluble does not mean solvent-free. Use the matching curing agent and ratio where required by the specific product. The current glass system uses a reference final bake of 160°C for 30 minutes.
Performance & customisation
Confirm alcohol resistance, water resistance, adhesion and appearance requirements for the specific formulation and application. No single immersion duration is assigned here to every glass coating; material selection can be based on the intended finish and requirements.
China has a mature, high-volume market for water-soluble glass coatings, allowing us to offer competitive material costs and a range of established options.