Complements Industry Standard Workflow

AATCC TM22 Spray Test Method for Water Repellency in Textile

Quantify the wetting signals behind your spray grade to speed QC decisions and reduce failed TM22 runs

Who this is for

QA/QC teams, fabric finishing engineers (stenter/coating lines), and R&D chemists responsible for DWR performance.

Positioning

Dropometer does not replace TM22. It adds quantitative wetting data that anticipates and explains the spray grade, so you run fewer, more successful full tests.

Last updated

June 4, 2026

Request Dropometer Quote View AATCC TM22 Official Method

TM22 Apparatus

Écrit par

Gurdeep Singh Saini

Holds a BASc in Mechanical Engineering (Ryerson) and an MASc from York University. He focuses on the custom AI behind the instrument.

COO at Droplet Lab

Technical Review by

L’équipe du laboratoire Droplet

Droplet Lab builds precision instruments and software for surface science measurement, specialising in contact angle analysis and surface tension characterisation. Used by researchers across materials science, pharmaceuticals, coatings, and advanced manufacturing, Droplet Lab's Dropometer has contributed to studies published in peer-reviewed journals including Advanced Functional Materials (Impact Factor 19). The team combines instrument engineering with deep domain knowledge in wettability science with a focus on practical accuracy.

Verified against AATCC TM22 (Revision: 2024)

Evidence Box

Standard:

AATCC TM22 (Spray Test) is the final pass/fail grade for water repellency.

Dropometer role in workflow:

Providing quantitative upstream wetting signals to anticipate/interpret TM22 outcomes; it does not replace TM22.

Primary outputs:

● CA @ 2.0 s (median across ≥5 spots)
● ΔCA (2→10 s) optional (wicking/time-dependence, penetration)
● Variability (IQR) (heterogeneity / non-uniform finish)

Calibration requirement:

Thresholds must be calibrated per fabric family by correlating Dropometer outputs to TM22 grades (10–20 swatches spanning grades). Recalibrate if weave/fiber/finish/cure/conditioning changes.

Protocol defaults (starting point):

10–15 µL DI water; capture at 2.0 s ± 0.2 s (optional 10.0 s ± 0.5 s); ≥5 spots; report median + IQR

Known limitations:

Porous/rough textiles can show strong time dependence; hysteresis (θₐ/θᵣ) is optional when stable; always report capture time because CA can change after deposition.

Controls & Data Quality:

Measure a known-good control swatch every batch/run. Reject and re-run a spot if droplet edge/fit QC fails (e.g., unstable baseline, irregular edge).”

Executive Summary

AATCC test • spray test • test method for water repellency

This page helps you answer one practical question: Is this fabric lot likely to pass AATCC TM22 and, if not, what should we adjust first (finish chemistry, cure, or fabric structure) before we waste time running the spray test?

Those outputs enable immediate action: you can gate lots into Green/Yellow/Red (send to TM22 now, re-check/adjust, or hold and triage), and you can use the same numbers with a known-good control swatch to detect drift early and target corrections upstream instead of “spray-and-guess.”

How Dropometer Fits the Workflow

We recommend using TM22 as your final pass/fail gate, and adding Dropometer upstream as a pre-screen and a triage tool.

Pre-screening (upstream “go/no-go” before TM22 spray)

Immediately after finishing (or incoming QC), measure:

CA @ 2.0 s (repellency signal)
CA @ 10.0 s (porous/wicking sensitivity)

Textile wetting is often time-dependent, so a fixed capture time is essential for comparability. A large time drop often indicates absorption dynamics and penetration pathways that can later show up as poorer spray grades.

Root-cause triage (fast, practical but not overly binary)

Use a “most likely cause + rule-out check” approach:

Time-dependence dominant (wicking/penetration): Big drop from CA@2s to CA@10s or strong spot-to-spot variability suggests absorption dynamics; standardize capture time and consider two timepoints for that fabric family. This is often where penetration effects show up first on open structures.
Adhesion/pinning tendency (optional): High hysteresis (if stable to measure) commonly reflects roughness/heterogeneity and contact-line pinning—useful diagnostically, not uniquely “texture-only.”
Chemistry drift (optional): SFE trends from Neumann / Fowkes / Oss & Good can support a “finish chemistry changed/patchy” hypothesis when run with consistent probe liquids and compared against a known-good control swatch.

Validated measurement approach

Independent benchmarking and publication-based validation references.

Benchmark Validation

Our Contact angle and pendant‑drop surface tension methods have been benchmarked against KRÜSS DSA100E reference measurements.

See peer‑reviewed validation

Publication Evidence

Our instruments are referenced in peer‑reviewed journals, theses, and conference publications

Browse the full citations list

Calibration first

AATCC TM22 • aatcc test

TM22 is commonly used for screening, but your numeric gates must be calibrated per fabric family (weave, fiber blend, finish, cure line).

Build your TM22 correlation in one shift

Select 10–20 swatches spanning known TM22 grades (or intentionally varied add-on/cure).

Measure on each swatch (and the control swatch each run):
• CA @ 2.0 s
• CA @ 10.0 s
• Spot-to-spot spread (IQR)
• Optional: θₐ, θᵣ (only if stable)

Run TM22 on the same swatches.

Output: a simple Green / Yellow / Red rule set for that fabric family.

Re-calibrate when: weave spec changes, finish chemistry changes, cure recipe changes, or major conditioning changes.

Example output

Below is an example of what your calibrated "gates" might look like for one fabric family. Treat these as placeholders not universal thresholds.

Gate	Typical TM22 outcome	CA @ 2.0s (median)	ΔCA = CA(2s) − CA(10s)	Optional: hysteresis Δθ	What to do
Green	90–100	≥ 135°	≤ 10° drop	≤ 15° (if stable)	Send to TM22 confirm
Yellow	80–90	125–135°	10–25° drop	15–30°	Check cure/add-on; re-test 1–2 swatches
Red	≤ 70	< 125°	> 25° drop	> 25° drop	Hold lot; triage root cause before TM22

Why the timepoints matter: contact angles on fibrous/cellulosic/porous surfaces can decrease with time as wetting/penetration proceeds, so "CA without a timestamp" is not comparable.

A scatter plot of TM22 grade vs CA@2s, colored by Green/Yellow/Red bands

A second plot of ΔCA(2→10s) to visualize wicking sensitivity

Business impact — Before/After Dropometer

Metric	Before Dropometer	With Dropometer
Lab Cycles	TM22 loops to discover failure	Fewer TM22 runs wasted on “dead-on-arrival” lots; faster screening.
Root Cause	Chemistry vs structure unclear	CA@time + ΔCA + variability
Scrap Rate	Failures discovered late	Drift detection during the run using control swatch + numeric gates.
Supplier Disputes	“Looks wet” arguments	Timestamped numeric QC targets improve traceability.

Instant ROI Snapshot

Calculate your savings in real time.

Monthly tests

Labor rate per hour ($)

Run time per test (Minute)

Result

≈0

hrs/month saved

≈$0

/month ROI

Where do these numbers come from? i You enter your current total time per test (dispense + record + analyze + save). The calculator assumes that our Dropometer reduces that workflow to ~1.1 minutes per test (dispense + capture + automated fit + export). Time saved per test = max(0, your time − 1.1 min). Monthly hours saved = (monthly tests × minutes saved per test) ÷ 60, and monthly savings = hours saved × labor rate.

QC-ready quick protocol (SOP card)

AATCC • spray • water repellency

Goal: Repeatable numbers that correlate with TM22 trends.

Sample handling

• Condition swatches to your lab standard (define RH/temp).
• Use consistent coupon size and orientation.

Setup

• Clamp coupon with defined tension (consistent slack removal).
• Always include one control swatch (known good) every batch/run.

Measurement (baseline method)

• Dispense 10–15 µL DI water drop (starting point; tune per weave).
• Capture CA @ 2.0s ± 0.2s, and optionally CA @ 10.0s ± 0.5s.
• Replicates: ≥5 spots per swatch; record median + IQR.

If advancing/receding is unstable on your textile (common on open weaves)

Advancing/receding angles can be difficult on rough/porous fabrics. If θᵣ is noisy or fails QC, use an adhesion proxy instead:

• ΔCA(2→10s) (bigger drop = more wicking/penetration)
• Spot-to-spot variability (IQR) (bigger spread = heterogeneity/nonuniform finish)

keep Δθ as "optional when stable." This still aligns with known drivers of hysteresis/pinning without forcing a fragile measurement.

Method Settings (SOP-Ready)

Parameter	Recommended Setting	Technical Rationale
Geometry	Sessile Drop (Static) + Optional advancing (θₐ) and receding (θᵣ) where stable	Static CA provides a fast repellency screen. Hysteresis is diagnostic but can be difficult on porous/rough textiles.
Timepoints	2.0s (primary), optional 10.0s	Textiles can show strong time dependence due to penetration/wicking; timestamping improves comparability.
Optional Δθ	θₐ and θᵣ when stable	Diagnostic for pinning/heterogeneity; optional only.
Droplet Volume	10–15 µL (starting point; calibrate per fabric family)	Validate during correlation building so gates match your TM22 program.
Liquids	DI water (baseline). For SFE modeling, select liquids based on the model used.	Neumann: 1 liquid; Fowkes: multiple liquids; Oss & Good: ≥3 liquids (e.g., water + diiodomethane + glycerol often used in practice).
Replicates	≥5 spots + median/IQR	Fabric heterogeneity is real; spread improves correlation to TM22 outcomes.

Decision tree (probabilistic) — triage + rule-out checks

spray • textile

Start: TM22 grade trending down OR pre-screen hits Yellow/Red.

A) Chemistry drift suspected

Signals:

CA@2s down + control swatch stable; optional Fowkes may show polar component increasing, or Oss & Good may show Lewis acid/base terms shifting—treat as a trend vs control, not a stand-alone verdict

Rule-out:

verify add-on %, cure profile; compare to control swatch and a retained “golden” sample

B) Structure/heterogeneity suspected

Signals:

CA@2s acceptable but variability high; optional Δθ high (if stable).

Rule-out:

confirm weave/roughness spec and coating uniformity; compare face/back sides if relevant.

C) Wicking/time-dependence dominates

Signals:

CA@2s high but CA@10s collapses; strong sensitivity to time/placement.

Rule-out:

enforce capture times; consider reporting both timepoints for that family

A flowchart version of above process

Interpretation

(AATCC test method • spray)

Contact angle at a fixed time (e.g., CA @ 2.0 s): primary upstream screen for whether a lot is trending toward a TM22 miss; calibrate thresholds per fabric family.

Time dependence (e.g., CA @ 2.0 s vs CA @ 10.0 s): a large drop indicates wetting/penetration dynamics dominating on that fabric.

Hysteresis (Δθ), when stable: higher hysteresis often reflects stronger pinning from roughness/heterogeneity; triage signal only.

SFE trends (Neumann / Fowkes / Oss & Good): supporting evidence for finish drift relative to control swatch; keep liquids/timepoint/volume/conditioning fixed.

Common pitfalls & limits

(spray • water repellency)

On open weaves or bouncy knits, the droplet may settle into the fabric structure over time. Always report the capture time (e.g., “measured at 2.0s”). Do not compare a 2-second reading with a 10-second reading.

Hysteresis isn’t single-cause proof: roughness/heterogeneity/pinning dominate; use as a diagnostic with rule-outs.

Replicates matter: spot-to-spot spread is meaningful on textiles—keep it.

Legal note (AATCC test method)

This page summarizes how Dropometer supports TM22 programs and does not reproduce AATCC text or confer third-party certification. Always consult the official AATCC method for full requirements and the official evaluation scale.

View AATCC TM22 Official Method Request Dropometer Quote

How this page was created

Editorial and technical transparency notes for this page.

Transparency Details 4 checklist items

Drafting assistance

An initial draft was created with AI assistance (ChatGPT 5.2 Pro).

Technical review

Reviewed and edited for technical accuracy by Droplet Lab Team.

Verification steps

Standard identifiers, units, thresholds, and key procedural claims are checked against cited sources before publication.

Updates

Reviewed every 12 months or when the underlying standard changes.

Report a correction

Spotted an issue in this summary? Send a correction request and our team will review it.

Correction Request

We work hard to keep this standards summary accurate and up to date. If you spot an error (wrong revision/year, missing requirement, incorrect interpretation, or broken link), tell us and we'll review it.

Références

1. AATCC TM22 — Test Method for Water Repellency: Spray Test

2. AATCC article — "The Art of Testing: Water Repellency"

3. AATCC RA63 — Water Resistance Test Methods committee page

4. Owens, D.K.; Wendt, R.C. (1969) — "Estimation of the surface free energy of polymers." J. Appl. Polym. Sci.

5. Fowkes, F.M. (1964) — "Attractive Forces at Interfaces." Ind. Eng. Chem.

6. Hejda, F., Solař, P., Kousal, J. (2010) — "Surface Free Energy Determination by Contact Angle Measurements" WDS Proceedings

AATCC TM22 Spray Test Method for Water Repellency in Textile

Gurdeep Singh Saini

L’équipe du laboratoire Droplet

Featured Studies & Publications

Evidence Box

Executive Summary

How Dropometer Fits the Workflow

Pre-screening (upstream “go/no-go” before TM22 spray)

Root-cause triage (fast, practical but not overly binary)

Validated measurement approach

Calibration first

Example output

Business impact — Before/After Dropometer

Calculate your savings in real time.

QC-ready quick protocol (SOP card)

Sample handling

Setup

Measurement (baseline method)

Method Settings (SOP-Ready)

Decision tree (probabilistic) — triage + rule-out checks

A) Chemistry drift suspected

Signals:

Rule-out:

B) Structure/heterogeneity suspected

Signals:

Rule-out:

C) Wicking/time-dependence dominates

Signals:

Rule-out:

A flowchart version of above process

Interpretation

Common pitfalls & limits

Legal note (AATCC test method)

How this page was created

Drafting assistance

Technical review

Verification steps

Updates

Report a correction

Références