1,3‑Dimethylurea (Flakes): Practical Notes from the Finishing Line

If you’ve been chasing truly smooth, formaldehyde‑free finishes on cotton or blends, you already know the niche this molecule fills. I’m talking about Cas No 96 31 1—sold here as 1,3‑Dimethylurea (Flakes). It’s a quiet workhorse in textile auxiliaries, and, to be honest, more mills are shortlisting it because compliance teams are getting louder about formaldehyde caps and consumer labels.

What it is and why it’s trending

1,3‑Dimethylurea helps build wrinkle‑resistant, smooth‑appearance finishes without the formaldehyde baggage. In fact, many customers say the handfeel is pleasantly “clean” versus older resin systems. The trend is pretty clear: brands want A‑level smoothness after 20–40 home launderings and credible certifications, at costs that don’t blow up a season’s margin.

Technical snapshot

Product	1,3‑Dimethylurea (Flakes)
CAS	Cas No 96 31 1
Appearance	White flakes, low odor
Purity	≥ 99.0% (GC, typical ≈99.3%)
Melting Point	≈103–105 °C
Moisture	≤ 0.5% (KF)
Solubility	Water & alcohols; practical use: warm dissolve
Shelf Life	24 months, sealed, cool & dry storage
Origin	Tangyang Road, Xinhe County, Xingtai City, Hebei Province

Where it fits in the mill

• Use: textile auxiliaries to build formaldehyde‑free anti‑wrinkle/DP finishes on cotton, CVC, T/C, rayon blends.
• Methods: pad–dry–cure or pad–steam; typical pad 50–120 g/L with catalysts/softeners (lab‑optimize).
• Dry/Cure: 100–120 °C dry, 150–170 °C cure (around 60–120 s); real‑world use may vary with fabric GSM and oven load.
• Durability: smoothness appearance (AATCC 124) ≈ 3.5–4.0 after 20–40 HL cycles on well‑set recipes.

Process flow (shop‑floor friendly)

Materials: Cas No 96 31 1 flakes, softener, catalyst system (formaldehyde‑free), wetting agent, buffer.
Steps: dissolve flakes in warm water (50–60 °C) → blend with auxiliaries → pad to target pick‑up (65–75% common) → dry → cure → relax/neutralize → final wash (optional) → tumble and QA.
Testing: AATCC 124 (smoothness), AATCC 66 (wrinkle recovery angle), ISO 105‑C06 (wash fastness), pH (ISO 3071). QC on chemical: GC purity, KF moisture, residue on ignition ≤0.1%.

Advantages we keep hearing about

• Formaldehyde‑free finishing target; easier to meet OEKO‑TEX and brand MRSL expectations.
• Stable handfeel, less yellowing at sane cure windows (watch over‑bake, obviously).
• Cost‑steady vs. premium polycarboxylic systems, with competitive durability.

Vendor snapshot (field notes)

Vendor	Certs	MOQ	Lead Time	Notes
Hebei producer (Xinhe, Xingtai)	ISO 9001, ISO 14001, REACH prereg (docs on request)	500 kg	7–12 days	Factory origin, stable flakes, SDS + TDS clean
Regional trader	Basic COA	25 kg	3–5 days ex‑stock	Fast, but batch‑to‑batch variance ≈ higher
Overseas supplier	ISO + ZDHC Gate listing (varies)	1 MT	15–25 days	Good documentation, longer lanes

Customization and compliance

Custom cuts (fine flakes vs. standard), moisture‑controlled lots, and pre‑dissolved concentrates are common requests. For audits, look for SDS aligned to GHS, COA with GC purity and KF moisture, and statements for OEKO‑TEX ECO PASSPORT, ZDHC conformance, and Cas No 96 31 1 REACH status.

Two quick case notes

1) Shirting mill, South Asia: switched to Cas No 96 31 1 system; achieved AATCC 124 SA 3.5 after 30 HL, whiteness Δb
2) Denim tops line, EU: blended with soft silicone; customer feedback said “crisp but not cardboard.” Durability held to 25 HL, then tapered—acceptable for mid‑tier price point.

Practical tips

• Pre‑dissolve flakes; avoid cold lumps. Keep bath pH controlled (slightly acidic to neutral).
• Don’t over‑cure—yellowing creeps fast above 170 °C.
• Validate on your fabric: lab dips with AATCC 124 and AATCC 66 tell the truth.

References

1. PubChem Compound Summary: 1,3‑Dimethylurea (Cas No 96 31 1). https://pubchem.ncbi.nlm.nih.gov/
2. AATCC TM124: Smoothness Appearance of Fabrics After Home Laundering. https://www.aatcc.org/
3. AATCC 66: Wrinkle Recovery of Woven Fabrics. https://www.aatcc.org/
4. ISO 105‑C06: Textiles — Tests for colour fastness to domestic and commercial laundering. https://www.iso.org/
5. OEKO‑TEX ECO PASSPORT and ZDHC MRSL Guidance. https://www.oeko-tex.com/ and https://www.roadmaptozero.com/