Prepared by Relanet New Materials (Guangzhou) Co., Ltd. · Content updated
- Define the stack
- Record the process
- Run separate tests
- Review the evidence
1. Define representative specimens
Map the fabric, foam, supporting layer and each adhesive interface. Identify material grades, suppliers, batches, thicknesses and existing surface treatments. Omit a foam layer if the real assembly has none.
Specify sampling location, direction, dimensions, replicates and conditioning. Strip specimens help compare interfaces; curved, edge or assembly samples examine holding and deformation in representative geometry. Neither replaces the other.
- Keep unaged controls and separate trial groups when changing materials, cleaning or surface treatment.
2. Record the process before comparing adhesives
Record the adhesive and curing-agent names and batches. Add the document version, weighing method and mixing start time. Record how the adhesive was applied and its coat weight. Follow the current technical data for mixing and use conditions.
Document the environment, drying, activation, pressing and release. Separate equipment settings from measured adhesive-layer or substrate temperatures. Distinguish water removal from heat activation. Mark unknown settings for confirmation.
- Link the operation sequence, unusual observations and photographs to each sample group.
3. Separate the three strength stages
Initial tack is the immediate grab under stated contact conditions. Early holding shows whether a sample can stay in place during a handling task. It is sometimes called green strength. To measure initial bond strength, state the early test time and method. Tack is not a peel-force result. For final bond strength, state the cure, conditioning and test time.
For a peel test, record the angle, speed and strip width. State whether the result is a peak or an average. Record where the sample failed. Keep the original units when comparing results. Note whether the foam or fabric tore. A one-minute peel result from another material stack cannot replace this project’s final-strength test.
4. Schedule five evaluation checkpoints
Agree the requirements and methods before testing. Some checks need separate samples. Use the customer specification or project agreement to set acceptance values. Keep each result marked “Pending test” until its records are available.
| Checkpoint | Evaluation | Conditions to record | Result |
|---|---|---|---|
| Initial tack, early holding and initial bond strength | Observe immediate grab and transfer or release hold separately; measure initial peel at a defined early time | Material stack, contact and pressing, elapsed time, early measurement time and method | Pending test |
| Coating sag resistance | Movement, pooling or coverage change in the wet coating | Coat weight, viscosity method, orientation, environment and observation time | Pending test |
| Heat resistance and assembly creep | Displacement, sag and bond retention under defined heat and load | Temperature, duration, load, orientation, geometry and failure criteria | Pending test |
| Humidity aging and hydrolysis risk | Bond changes after conditioning; hydrolysis needs relevant evidence | Cure, humidity/water exposure, temperature, duration and controls | Pending test |
| Final bond strength | Strength and failure mode after specified cure, conditioning and required aging | Cure/conditioning, peel geometry, speed, width and failure location | Pending test |
5. Compare aging results and failure locations
Wet-coating sag occurs before bonding. Assembly sag or creep occurs after the part is bonded. A viscosity result alone cannot show whether the headliner will hold its shape under heat and load. Record these checks separately.
After humidity aging, compare strength, appearance, displacement and failure mode. Water uptake, material changes and interface conditions can affect results. Humidity aging alone does not prove a hydrolysis mechanism; define the question and evidence needed.
- Classify interface, adhesive, foam or fabric failure and link photographs.
- Keep anomalous results; do not pool trials with incompatible conditions.
6. Decide the next trial or project step
Link each result to a requirement and its test record. Leave missing results or limits pending. Decide whether to screen more materials, retest one changed factor or move to the next sample stage.
Before releasing a report for technical review, link each result to its specimen identifier, process sheet, conditioning history, raw curve or observation, and the applicable requirement. Mark missing fields explicitly. The R-5670/R-60C peel article illustrates a separate published material-pair record; its values are not acceptance limits for this headliner plan.
Send RELANET the material stack, process, failure photos, test requirements and project stage. Request the current TDS/SDS and sample details for R-5670 with R-60C. A sample trial and production approval are separate steps.
Does bonded foam or a passed peel test prove NVH noise reduction?
No. A bonding result is not an acoustic result for the actual assembly. If the project includes NVH requirements, arrange a separate acoustic evaluation of the actual assembly and retain its material stack, assembly state and test conditions. Do not infer noise reduction from foam failure or a peel reading.
How should specimen and assembly results support a project review?
Keep separate evidence records for specimen bonding, assembly durability and acoustic evaluation. Link each to its own project requirements and decision basis, then list what remains unverified. The headliner application guide is a starting point for discussion, not a substitute for these tests or proof of acoustic acceptance.
Questions and answers
Is this plan a headliner acceptance standard?
No. It organizes specimen, process and result records. Confirm methods, sampling, limits and decisions against the customer specification or project agreement.
Does a non-sagging wet coating prevent assembly sag?
Not necessarily. Wet coating behavior and bonded-assembly creep occur at different stages and need separate coating and assembly evaluations.
Has R-5670 passed the headliner tests described here?
This article makes no such claim. R-5670 with R-60C is a candidate for discussion; suitability needs current technical data and traceable project results.