BTMS-50 CAS 81646-13-1 | Conditioning Emulsifier for Hair Care | Supplier — Onerchem
BTMS-50 (Behentrimonium Methosulfate & Cetyl Alcohol, 50%) — cationic conditioning emulsifier for hair conditioners, masks, and leave-in treatments. COA/MSDS available. B2B cosmetic ingredient
“Wholesale Pricing Available”
“Global Shipping – Technical Support Included”
Description
Onerchem · Hair Care & Emulsifiers · Cationic Conditioning
BTMS‑50
Conditioning Emulsifier
Behentrimonium Methosulfate & Cetyl Alcohol · CAS 81646-13-1 · 50% Active
A positively-charged conditioning emulsifier that builds stable oil-in-water emulsions while depositing a substantive lubricating film on hair and skin — combining emulsification and conditioning in a single raw material.
01
Specification Parameters
INCI Name
Behentrimonium Methosulfate (and) Cetyl Alcohol
CAS Number
81646-13-1
Active Content
50%
Behentrimonium Methosulfate
Appearance
White to off-white waxy solid / flakes
Melting Point
65 – 75 °C
pH (3% aq.)
4.0 – 6.0
Charge Type
Cationic (permanently positive)
HLB Value
~11 — O/W emulsification
Processing Phase
Oil phase at 70–75 °C
Use Level
2–4% rinse-off conditioner · 4–6% leave-in · 6–10% intensive mask · 4–7% body lotion
Compatibility
Compatible with oils, fatty alcohols, silicones, nonionic and amphoteric systems. Incompatible with anionic surfactants (SLS, SLES, ALS) — opposite charges form insoluble complexes that precipitate.
Storage
Below 30 °C, dry. Shelf life 24 months sealed.
Documentation
COA & MSDS available with every order. Cosmos-approved when sourced from certified supply chain.
02
Technical Profile
01
Primary Function
Oil-in-Water Emulsification
Provides reliable O/W emulsification across oil loadings up to 30%. The cetyl alcohol co-emulsifier builds a structured lamellar phase at the oil-water interface — a crystalline bilayer that resists separation without additional stabilisers. HLB ~11 positions it effectively for medium-polarity oils common in hair and skin formulations.
02
Conditioning
Substantive Cationic Film Deposition
Hair and skin surfaces carry a net negative charge at physiological pH. BTMS-50's permanently positive quaternary nitrogen adsorbs electrostatically to these surfaces, orienting the C22 behenic tail outward as a conditioning film. This bond is strong enough to resist rinsing — delivering wet slip, dry softness, and detangling performance that persists post-wash.
03
Texture
Rich, Cream Rheology
At 4–8%, BTMS-50 produces the characteristic thick, scoopable texture of rinse-off conditioners and masks without synthetic thickeners. The waxy cetyl alcohol component gives a semi-solid room-temperature body that melts on contact, ensuring even application and controlled distribution through the hair or across the skin surface.
04
Anti-Static
Flyaway & Frizz Reduction
Triboelectric charging builds excess negative charge on hair through friction or low humidity. The cationic charge of BTMS-50 partially neutralises this, reducing inter-fibre electrostatic repulsion — the cause of flyaway and frizz. Particularly effective in leave-in treatments for dry, chemically-processed, or fine hair in low-humidity climates.
05
Safety Profile
Milder Than Earlier Generation Quats
The long C22 chain significantly reduces aqueous free-ion concentration — the primary driver of quaternary ammonium-induced irritation — giving BTMS-50 a substantially lower irritation and sensitisation potential than cetrimonium chloride or benzalkonium chloride. Suitable for leave-on applications and sensitive skin formulations where older quats would be borderline.
BTMS-50 is a two-component blend. The 50% behentrimonium methosulfate delivers conditioning and charge; the 50% cetyl alcohol provides emulsification structure and texture. Each is indispensable — neither achieves the same result alone.
Behentrimonium methosulfate is a quaternary ammonium compound with a C22 (behenic) alkyl chain and a permanently quaternised nitrogen head group. The methosulfate counterion is notably milder than chloride or bromide counterions used in older quats — it does not form toxic halides and has better mucosal tolerance.
The electrostatic mechanism: hair cuticle surfaces carry a net negative charge from anionic sulfonate and carboxylate groups in keratin proteins — amplified in bleached, heat-damaged, or high-porosity hair. The positively-charged nitrogen adsorbs to these sites through coulombic attraction, orientating the C22 tail outward as a monomolecular lubricating film.
This film is substantive — ionic bonding strength resists rinsing. The C22 tail reduces fibre-to-fibre friction, improving wet and dry combing performance that persists post-rinse. Substantivity increases with hair damage level, making BTMS-50 more visibly effective on processed or damaged hair than on virgin cuticle.
Formulator note: Position end-products containing BTMS-50 for bleached, heat-styled, or chemically-processed hair for maximum visible performance differentiation.
Cetyl alcohol (C16 fatty alcohol) acts as co-emulsifier and rheology modifier. Combined with BTMS, it forms a lamellar liquid crystal phase at the oil-water interface — a structured bilayer arrangement that stabilises the emulsion mechanically by increasing interfacial film rigidity and building a gel network within the aqueous phase.
This lamellar architecture produces the characteristic heavy, creamy texture of BTMS-based conditioners — distinct from lighter nonionic emulsifier systems. It also provides long-term physical stability: the crystalline network resists coalescence and Ostwald ripening under thermal stress, the primary failure modes of simple emulsions in distribution and shelf storage.
Cetyl alcohol contributes secondary conditioning through its own lubricity and through occlusive film formation on the hair shaft, supplementing the electrostatic conditioning of the quat head group.
The permanent positive charge of BTMS-50 creates a fundamental electrostatic incompatibility with anionic surfactants. When cationic quaternary ammonium compounds meet anionic species, the charges attract to form an insoluble ion-pair complex that precipitates as a waxy, turbid mass — destabilising the emulsion.
BTMS-50 is therefore limited to surfactant-free systems (conditioners, masks, body butters) or systems where the surfactant is nonionic or amphoteric. If the formulation requires any cleansing action, use cocamidopropyl betaine at controlled ratios and test for clarity and absence of precipitation before scaling up.
Incompatible with: SLS, SLES, ALS, sodium cocoyl isethionate (anionic form), sodium methyl lauroyl taurate at high concentration. Safe with: nonionic emollients, silicones, fatty alcohols, polyquaterniums, behentrimonium chloride at low levels.
2–4%
use level
Rinse-Off Conditioner
Daily lightweight. Add 1% cetrimonium chloride for enhanced slip. Finish at pH 4.0–5.0.
4–6%
use level
Leave-In Treatment
Light emulsion for daily detangling. Lightweight oils only (camellia, argan). Total oil phase ≤ 15%.
6–10%
use level
Deep Conditioning Mask
Weekly intensive treatment. Penetrating oils (coconut, olive). Add Ceramide NP 0.5% for cuticle repair. pH 4.5–5.5.
4–7%
use level
Body Butter / Lotion
Skin conditioning emulsions with velvety feel. Cationic charge improves skin adhesion vs. nonionic systems.
3–5%
use level
Shaving Cream
Pre/post-shave conditioning emulsion. Reduces razor friction and post-shave irritation perception.
T1
Processing: Melt BTMS-50 in the oil phase at 70–75 °C. Add oil phase to water phase (also heated to 70–75 °C) with moderate agitation. Never add to cool water — it resolidifies into lumps before dispersing.
T2
pH: Finish hair formulations at pH 4.0–5.0 to mimic the hair's natural pH and keep the cuticle closed. For skin applications pH 5.0–6.0 is acceptable. Adjust with lactic acid or citric acid — avoid strong mineral acids.
T3
Anionic check: Never combine with SLS, SLES, or other anionic surfactants in the same phase. If the formula requires a cleanser, use nonionic or amphoteric types only. Always test for clarity and absence of precipitation at bench scale before scaling up.
T4
Texture tuning: For richer textures, increase oil phase up to 30% or add C20–22 fatty alcohols. In warm climates, reduce cetyl alcohol proportion slightly to prevent over-solidification at low ambient temperatures in finished product.
T5
Performance boosters: Polyquaternium-10 (0.1–0.5%) adds film deposition and shine. Hydrolysed keratin or silk peptides (1–2%) for protein-conditioning synergy. Panthenol (0.5–2%) adds humectancy. Dimethicone (0.5–1%) for slip and frizz control.
03
Frequently Asked Questions
Both contain behentrimonium methosulfate as the active conditioning compound. BTMS-50 has 50% active with 50% cetyl alcohol — producing a richer, heavier emulsion with more pronounced conditioning and creamier texture. BTMS-25 has 25% active, creating lighter, more fluid emulsions. BTMS-50 is standard for rinse-off conditioners and masks; BTMS-25 suits light leave-in sprays.
Not in standard shampoos using anionic surfactants. The cationic charge will complex with anionic surfactants (SLS, SLES), causing precipitation and formulation instability. For no-poo or co-wash formats with entirely nonionic or amphoteric surfactant systems, BTMS-50 can be included — but these produce minimal lather by design.
BTMS-50 is Cosmos-approved when sourced from certified sustainable supply chains (behenic acid typically from rapeseed or sustainable palm). It qualifies as a nature-derived ingredient under COSMOS standards. Not considered 100% natural due to the quaternisation chemistry, but widely accepted in certified-natural formulations. Onerchem provides full sourcing and certification documentation.
For penetrating conditioning: coconut oil, olive oil, avocado oil (low molecular weight, reach the cortex). For surface lubrication and shine: argan oil, camellia oil, marula oil. For scalp focus: jojoba (liquid wax, non-comedogenic), rosehip oil. Keep total oil phase ≤ 25% for rinse-off masks. Silicones (dimethicone, cyclomethicone) at 1–3% add slip and shine without weighing down the hair.
Most common causes: (1) Oil phase too high — reduce all oils and butters by 20–30%; (2) BTMS-50 concentration too high — try 3–4% and reassess; (3) Heavy oil selection — replace castor oil, shea butter, or beeswax with lighter alternatives like camellia or baobab; (4) pH too high — above pH 6.0, BTMS-50 emulsions can feel tackier; drop to pH 4.5–5.0. Adding isopropyl myristate (0.5–1%) improves spread and absorption without significantly affecting conditioning.
Reviews (0)
Shipping and Delivery
Onerchem B2B
✈ Ships from China
Shipping &
Delivery
All orders ship from our facility in mainland China. Samples are dispatched within 7 working days. Bulk orders follow a confirmed production schedule — with full documentation in every parcel.
≤7
Days · Sample dispatch
15–40
Days · Bulk lead time
Global
EU · GCC · ASEAN · NA
COA
Included every shipment
Dispatch Timeline
When does my order ship?
Dispatch timelines differ between sample and bulk orders. A confirmed dispatch date is always provided at order confirmation.
Sample Orders
≤7 working days
From order confirmation to dispatch
Samples are QC-checked, weighed, and packed individually. Your COA and MSDS are printed and included in the parcel before sealing. Most sample orders ship ahead of the 7-day window.
Tracking number provided on dispatch · Express courier available on request
Bulk Orders
15–40 working days
Varies by quantity and specification
Lead time is determined by order volume, packaging format, and whether custom labelling or documentation is required. A production and dispatch schedule is confirmed in writing at the time of order.
Schedule confirmed at order · Progress updates available on request
Process
From order to delivery
Four steps from confirmed order to goods in hand.
01
Order Confirmed
Written confirmation sent within 1 business day. Dispatch schedule and freight quote included for bulk orders.
02
QC & Packing
Batch is QC-checked against HPLC data. COA and MSDS are generated and packed with the shipment.
03
Dispatch
Shipment handed to carrier. Tracking number and commercial invoice sent to buyer by email on the same day.
04
Delivery
Goods arrive at destination. 7 working-day inspection window begins from the confirmed delivery date.
Transit Times by Region
Estimated time in transit
Transit estimates run from dispatch date and exclude customs clearance time, which varies by country and commodity.
| Region | Est. Transit | Notes |
|---|---|---|
| EU & UK | 7–14 days | Import duties and VAT assessed at customs — payable by buyer. REACH compliance documentation available on request. |
| GCC / Middle East | 5–10 days | Customs clearance handled by buyer or nominated freight agent. Certificate of Origin available on request. |
| ASEAN | 4–8 days | Country-specific import licences or permits may apply for certain actives. Buyer is responsible for pre-shipment compliance checks. |
| North America | 7–14 days | FDA Prior Notice may be required for cosmetic actives. Buyers are advised to confirm import classification before ordering. |
| Other Regions | 10–20 days | Contact us to confirm shipping availability and any documentation requirements specific to your country. |
All transit times are estimates only · Delays may occur due to customs inspection, public holidays, or carrier disruption
Freight & Documentation
Costs and paperwork
Freight is quoted individually based on weight, destination, and Incoterm. Full shipping documentation is prepared for every order.
Freight Policy
—Freight cost quoted at order confirmation
—Rates based on gross weight, destination, and selected Incoterm
—Express courier (DHL / FedEx / UPS) available on request
—Sea freight available for larger bulk orders
—Import duties and local taxes are the buyer's responsibility
Documents Included
✓Commercial Invoice
✓Packing List
✓Certificate of Analysis (batch-specific)
✓MSDS / Safety Data Sheet
✓Certificate of Origin — on request
Need a freight quote or shipping advice?
Email us with your destination, estimated order weight, and preferred Incoterm — we'll respond within 1 business day.
Global shipping
EU · GCC · ASEAN · Americas
Samples ≤7 working days
From order confirmation
Full documentation
COA · MSDS · Invoice · Packing list
Tamper-evident packing
UV-protected, sealed containers
Reviews
There are no reviews yet.