Fusible interlining — also called thermal interlining or simply interlining — is the invisible layer that decides a garment's shape: whether the collar holds, whether the placket blisters, whether the garment distorts after washing. It comes down to three base fabrics, four common coatings and three fusing parameters, and every one of them has to match the shell fabric. This guide covers base fabric selection, coatings and wash resistance, fusing parameters, matching rules, common defects and the acceptance checklist.
The conclusion first: nine out of ten interlining problems come from mismatching, not from the grade of the interlining itself.
1. Choosing Between Three Base Fabrics
| Base fabric | Characteristics | Typical positions |
|---|---|---|
| Woven | Dimensionally stable, good body, resists distortion in the wash, and the most expensive | Plackets, collars, cuffs, waistbands |
| Non-woven | Low cost, easy to cut, no fraying edges, but prone to blistering on large panels or with frequent washing | Small reinforcements, local support, pocket mouths |
| Knitted | Elastic with recovery, stretching with the fabric instead of restricting it | Knit collars, stretch wovens, activewear |
2. Four Coatings and Their Wash Resistance
| Coating (adhesive dots) | Melting range | Behaviour and use |
|---|---|---|
| PA, polyamide | about 110–130°C | Soft hand, good dry-clean resistance, best below 40°C in water — the general-purpose workhorse |
| PES, polyester | about 120–140°C | Strong wash resistance, tolerating 60°C, for shirts, workwear and anything washed hard |
| PE, polyethylene | about 90–110°C | Low-temperature fusing for heat-sensitive and coated fabrics; generally not dry-clean resistant |
| Other special adhesives | Depends on the supplier | For difficult fabrics such as coated or water-repellent finishes, or special wash requirements — always confirm by sampling |
3. Three Fusing Parameters: Temperature, Pressure, Time
A typical window is 130–150°C, 1.5–3 bar and 10–15 seconds, but the real ceiling is set by the fabric: too hot and synthetics glaze or melt at the edge, too much pressure and the adhesive dots strike through to the face — neither is reversible.
- Temperature: start from the fabric's tolerance ceiling and go 10–20°C lower for dark shades, coated fabrics and recycled fibres
- Pressure: too high strikes through, too low gives poor peel strength — test separately for thick and thin fabric and for each position
- Time: flat-bed and continuous fusing machines transfer heat differently, so test on your own equipment instead of copying a generic table
- Cooling: let the panel cool fully before moving or sewing it — pulling while still hot causes the worst delamination and creasing
4. Matching Rules: Where Blistering Really Comes From
- Shrinkage: keep the wash shrinkage gap between interlining and shell within 0.5–1%; the wider the gap, the finer and more numerous the blisters after washing
- Weight and body: choose per position and err on the firm side rather than the soft one; using one stiff grade throughout makes the whole garment feel boardy after washing
- Recovery: stretch fabric needs a knitted interlining or a low-melt adhesive, otherwise the shell recovers in the wash while the interlining does not and the seams go slack and creased
- Fabric state: pre-shrinking, silicone or softener content and water-repellent finishes all affect bond strength — find out the finishing route before ordering
5. Common Defects and Fixes
| Symptom | Usual cause | What to do |
|---|---|---|
| Blistering, delamination | Fusing temperature or time too low, or shrinkage mismatch | Re-confirm the three parameters and test interlining and shell shrinkage side by side |
| Adhesive strike-through | Excessive pressure or too high a coating weight | Lower the pressure and move to a lower coating weight or fine-dot interlining, testing thick and thin fabric separately |
| Boardy hand | Interlining weight or base density is too high | Switch to a lighter interlining or confine the reinforcement to a small area |
| Yellowing | Fusing too hot, or yellowing driven by phenolic compounds | Lower the temperature and shorten the time, or move to a non-yellowing formulation |
| Failure after dry cleaning | A coating that is not dry-clean resistant was chosen | Move to a dry-clean resistant coating such as PA and re-specify against the care conditions |
6. Enquiry and Acceptance Checklist
| Item | What to fill in |
|---|---|
| Fabric details | Fibre content, weight, colour, stretch or not, pre-shrunk and water-repellent finishes |
| Positions and area | Placket, collar, cuffs, waistband; area per piece and consumption ratio |
| Base and coating | Woven, non-woven or knitted; PA, PES or PE; weight and dot pattern |
| Care conditions | Wash temperature, tumble drying, dry cleaning and bleaching |
| Acceptance criteria | Peel strength, appearance after washing, shrinkage, hand and body requirements |
| Quantity and lead time | Roll or piece form, length per roll, and sampling plus bulk lead time |
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Choosing interlining for a shirt or knit line? Send the fibre content, weight and care conditions — we match the interlining per position and supply woven labels, care labels and tags to the destination rules, with test documents and fusing parameters, shipping physical samples in 3–7 days.
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