Liquid Delamination and Seam Failure
Executive summary
Read the broken join before you add more latex. Adhesive failure leaves glue on one side only. Cohesive failure splits the glue layer. On a multi-dip piece, layers can come apart from each other even when there was no separate cement: that is a ply split, usually timing or humidity, not a missing extra coat.
ASTM peel methods are lab classes. Use this with Liquid adhesives and Liquid reinforcement.
Peel modes
What is adhesive vs cohesive failure?
Adhesive failure: the glue let go from one surface. That face looks clean. Cohesive failure: the glue itself tore. Both sides show residue.
| Mode | What you see | Likely class |
|---|---|---|
| Adhesive | Glue on one piece only | Prep, contamination, polarity, never wetted |
| Cohesive | Glue split through its thickness | Weak film, slow dry, restricted coalescence, water |
| Fiber-pull | Textile fibers stuck in the glue | Textile side lost |
| Rubber-tear | Film tears away from the join | Film weaker than the bond |
| Ply split | Dip layers separate from each other | Underlayer dried or leached; low humidity |
Peel rate can flip cohesive and adhesive in the pressure-sensitive-adhesive study cited for this series. A slow hand peel is not a fast wear yank.
Multi-dip ply split
Bond strength between dips drops when the first layer is dried and leached before the next dip. Fresh wet gel is the window that maximizes adhesion. Fatty soaps (handbook example: potassium caprylate) hurt inter-ply adhesion. Low relative humidity can impair second-dip lamination.
If the hood or glove peels between coats, that is this class. See Liquid reinforcement.
Decision flow
text
1. Split the join — look at both faces
2. Classify mode (adhesive / cohesive / fiber / rubber / ply split)
3. Location? edge vs mid-panel
4. Age? fresh vs months
5. Fix class: re-prep vs wet-gel timing vs redesign the lap vs retireGlue family: Liquid adhesives. Textile face: Liquid latex–textile bonding. Rim coats: Liquid edge finishing.
Aged aqueous adhesive
Latex adhesives can be slow drying. Crosslinking improves temperature, ageing, water, and solvent resistance of the bond, and it cuts tack. In water-based PSA, a sulfur-donor cure aged better than colloidal free sulfur. Heat and oxidation can soften or embrittle films.
NR latex adhesive retains a high molecular-weight fraction that solvent-milled NR does not. That tape study is not a garment bake-off; it only says the two families are not the same film.
Deep dives (optional)
Deep dive: ASTM peel method classes
ASTM D903: peel/stripping of flexible bonds. ASTM D1876: T-peel, flexible-to-flexible. Report failure mode with force. Lab classes, not a garment grade.
Deep dive: Multi-dip window
Inter-ply bond drops when the first layer is dried and leached; fresh wet gel maximizes adhesion. Remedies in that industrial account: minimize underlayer drying and leaching; avoid excess fatty soaps.