Liquid hot-melt adhesives, also known as liquid modified hot-melt adhesives, exist as a homogeneous, flowable liquid at room temperature. They can be applied via coating, screen printing, or spray coating processes; after the solvents or moisture in the adhesive are removed using a tunnel-type drying oven, a thermoplastic adhesive film is formed. Subsequent thermal pressing then enables the achievement of high-strength adhesion. These adhesives are widely used in industrial roll-to-roll lamination and the fabrication of functional films. They exhibit broad substrate compatibility, and their applications can be broadly categorized into four main classes.
I. Plastic Film Category (Core Compatible Substrates)
This is the scenario in which liquid hot-melt adhesive is most widely used and where its performance characteristics best match the requirements.
General-purpose plastic films: Conventional plastic films—including PET, PVC, PU, and TPU—are all compatible. After heat pressing, the bonded interface becomes dense, providing excellent bend resistance and stable aging performance. These films are widely used in the lamination processing of decorative films, packaging composite films, and fabric substrates for bags and cases.
High-performance engineering films: High-temperature-resistant engineering films, such as PI (polyimide) and PEI, are key suitable materials for electronic-grade liquid hot-melt adhesives. These films offer high film-forming precision and excellent temperature resistance, enabling them to meet the composite requirements of high-end electronic devices, including flexible circuit boards and electromagnetic shielding films.
II. Metal Foil and Thin Metal Substrates
The liquid hot-melt adhesive formulated with modified components exhibits excellent wettability and interfacial adhesion to metal surfaces, enabling composite bonding between metal and plastic substrates.
It is compatible with materials such as aluminum foil, aluminum-coated film, copper foil, and stainless steel; certain high-temperature-resistant models, once cured, can withstand short-duration high-temperature shocks, making them suitable for short-duration soldering processes in electronic manufacturing.
III. Flexible Substrates for Fabrics and Leather
Water-based liquid hot-melt adhesives offer distinct advantages in this field; once cured, the adhesive layer exhibits flexibility and elasticity, preventing the substrate from becoming rigid or developing brittle cracks.
It can be bonded to a wide variety of fabrics, non-woven fabrics, genuine leather, and synthetic leather; it is resistant to repeated bending and machine washing. It is widely used in applications such as garment fabric lamination, automotive interior leather bonding, and footwear material lamination, offering superior environmental performance compared to traditional solvent-based adhesives.
IV. Other Industrial Substrates
In addition to the aforementioned mainstream categories, liquid hot-melt adhesives can also be used to bond materials such as glass fiber sheets, paper substrates, wood, rubber, and foam, making them suitable for diverse application scenarios—including insulating materials, food packaging, and industrial products—thereby offering high versatility.
The surface energy and temperature resistance thresholds of different substrates vary significantly; therefore, it is necessary to select the appropriate liquid hot-melt adhesive formulation based on the specific material. For electronic devices or high-temperature operating environments, it is recommended to prioritize specialized formulations with high temperature resistance and high bonding strength.
product recommendation
Product Name: JOMP1518K Hot-Melt Adhesive
Product Introduction: A single-component solvent-based modified hot-melt adhesive that can be applied to substrates such as PET and PI. It exhibits low initial adhesion at room temperature; upon high-temperature curing, it enables robust bonding across multiple material types, making it ideal for roller-coating mass production processes.
Product Features: Strong bonding strength, wide range of applications, uniform and stable film formation, and excellent bonding performance under high-temperature activation.
Application Fields: High-temperature bonding of coatings on various materials, including PET and PI, making it suitable for electronic functional films, industrial composite films, and other related applications.
Liquid Hot-Melt Adhesives: Check the Actual Bonding Surface
Using liquid hot-melt adhesives successfully requires more detail than identifying a sheet as plastic or metal. The adhesive contacts a surface finish, not the material name on a drawing. A coated film, a metallized face and the untreated reverse of the same web can behave differently during wetting and joining. Record which face is coated and which face receives the second substrate. Check for release agents, handling contamination and treatments applied earlier in production. Where surface treatment is part of the process, evaluate bonding on material that has followed the intended treatment and storage route. A freshly prepared sample may not represent a web that has waited before coating. For the liquid coating route described in this article, drying and later heat activation serve different purposes. Drying forms the coating and removes its carrier; activation allows the prepared film to participate in the subsequent bond. A coating that feels dry at the surface may still need investigation if the joined laminate develops bubbles or odor. Closing off the escape path too early can make a drying problem difficult to distinguish from an adhesion problem. Choose the process with both substrates in mind. Thin foils and heat-sensitive films can wrinkle, shrink or distort during heating, while porous textiles can absorb coating and leave less material at the joining surface. On a rough fabric, excessive penetration may produce a stiff region without establishing continuous contact with the mating layer. Why assume that a good bond to a smooth film predicts the result on a porous backing? It’s better to compare representative substrate pairs under the intended coating and pressing conditions. The JOME adhesive material catalogue can support a discussion of candidate formulations, with the coated face, carrier-removal route and activation method stated clearly. Include whether the laminate must remain flexible, retain a particular appearance or tolerate later manufacturing steps. Those constraints help define compatibility as a complete process question rather than a simple list of materials that might accept adhesive.
Find whether failure originates in drying, contact or service exposure
During lamination trials, liquid hot-melt adhesives should be judged on both bond continuity and the location of failure. Prepare specimens that include the same surface finish and coating method as the production laminate. Inspect the dried coating before closing the joint, since streaks, pinholes and areas of retreat become harder to see once another layer covers them. After activation and joining, check for wrinkles, bubbles and unbonded edges. A bend or peel evaluation can reveal weak contact that is not obvious in a flat specimen. Observe whether the adhesive remains on one substrate, separates within its own layer or pulls fibers or coating from the adherend. A torn surface coating is a different problem from poor adhesion to a clean metal face. Document that distinction before changing the adhesive formulation. Review heating and pressure distribution when defects cluster around an edge or appear in a repeated pattern. A platen or roller can establish uneven contact even when the coating itself is uniform. Cooling and handling also belong in the trial: moving the laminate before the bond has adequate stability can disturb an otherwise workable process. Use the selected material’s processing guidance and verify the result on the actual geometry rather than prescribing a universal pressing schedule. Service conditioning should reflect the finished article. Flexible fabric laminates may need repeated bending and exposure to the intended cleaning method. Electronic film laminates may need evaluation after subsequent assembly heating, with attention to dimensional movement and electrical function where relevant. Packaging or other contact-sensitive uses require their own suitability assessment; general bond strength does not establish that suitability. Compare conditioned and unconditioned specimens using the same separation method so that a change in testing does not disguise a change in behavior. If a coating remains intact but the bond loses strength, inspect both interfaces and the substrate surfaces again. Engineers can send these observations through JOME technical adhesive enquiries, alongside the material pair and process sequence. A useful trial record identifies what was coated, how it was joined and where it failed, making the next adjustment specific enough to evaluate.
The full JOME product catalogue named above is one part of the JOME production line. For the earlier discussion of What kind of adhesive is used in, follow the link, or browse the the full JOME bonding solutions line; specifications and samples go through the send drawings to the JOME team.