Fengfan CAS 2495-39-8 Sodium Allyl Sulphonate (ALS 25%) C3H5O3NaS

Product Overview

Sodium allyl sulphonate 25%, usually shortened to ALS 25%, is a clear, colourless to yellowish liquid supplied at a minimum concentration of 25.0%, with a density of 1.20–1.26 g/cm³ and a pH between 6.5 and 9.0. It goes into a nickel plating bath as the base brightener: the component that gives the deposit its general brightness and smoothness before the top brighteners and levelers do their work.

In a bright nickel plating bath the additives work in layers. The base brightener sets brightness and smoothness across the whole current density range. The top brightener sharpens gloss at the high current density end. The leveler works on the low current density areas and on fine structure. Sodium allyl sulphonate is the first of those three, and it is the layer most often missing when a panel comes out bright in the middle and dull at the edges.

The liquid form matters at the tank. It pumps and measures without dust, disperses quickly into the bath, and can be pre-diluted before it goes in. The specification is easy to work to on the shop floor.

Typical users are shops that run the process of electroplating nickel over steel, brass or zinc die-cast parts, and formulators who buy sodium allyl sulphonate as a component of their own additive packages. Both come for the same reason: they need the bottom layer of the bath to behave the same way every time it is made up.

One boundary is worth stating early. This is an additive for baths that deposit nickel under current. Electroless nickel plating works by chemical reduction from the bath itself and runs its own additive set, so this product has no part to play there.

Specifications

Product Advantages

• Consistent active content, drum after drum — supplied at ≥25.0% with density held between 1.20 and 1.26 g/cm³, so a measured volume gives the same addition from one delivery to the next.
• The foundation of a bright nickel plating system — brightness and adhesion across the current density range start here; a top brightener only has something to build on when this layer is right.
• A small addition that goes a long way — the working level is a few grams per litre, so the base layer is rarely the biggest item in a bath make-up and one drum covers a long run of top-ups.
• Fits the package you already run — made to sit alongside the top brighteners, levelers and wetting agents in an electro nickel plating bath rather than to replace them; the other components are adjusted around it.
• Same behaviour on repeat work — shops that sell nickel plating services on a standing order book get the same result from a fresh drum as from one opened months ago, which is what protects a quoted finish.
• No dissolving step at the tank — a true liquid that pre-dilutes in water, pumps cleanly and adds without dust or lumps.
• Less rework afterwards — with the base layer right, fewer parts come off the line needing a buff, a strip or a second pass.

Dosing and Bath Control

1. Measure the bath before you touch the brightener. Nickel content, pH and temperature first; if the bath is outside its normal window, correct that first, or you will not be able to tell what the addition did.
2. Work the addition out on bath volume, not drum size. The product goes into the working solution at 3–5 g/L. On a fresh make-up, add it before the tank is brought to final volume so it mixes through the whole body of solution.
3. Pre-dilute and add slowly under agitation. Pour into the working edge of the tank rather than over a rack of parts, so the concentrate disperses instead of landing on a component.
4. Check the result on a Hull cell panel across the full current density range. The panel tells you whether the change is brightness, coverage at low current density or burning at the high end, and therefore whether the base layer was what needed topping up.
5. Replenish on evidence, not on a calendar. A slow fall-off in brightness over a week usually points at the base layer; a sudden drop points at contamination or a top brightener out of balance.
6. Keep a dose log: volume added, date, panel result and any other component changed at the same time. On a metal plating process that runs the same parts for months, that log is what turns the next addition into a decision instead of a guess.
7. Do not push the base brightener to cure a high-current-density problem. If the panel burns at the high end while the low end is clean, the answer is usually in the top brightener or in the current density, not in more of this product.

Use Scenarios

• Decorative bright nickel on steel and brass — tapware, sanitary fittings, furniture hardware. The metal plating process for a cosmetic part is only as even as its base layer, and a weak one shows as a grey, patchy look under the chrome or the lacquer.
• Automotive trim and hardware — badges, brackets, trim and under-bonnet parts. On a rack carrying parts of different sizes, the base layer is what keeps the low current density areas from going dull while the high end stays bright.
• Electronics and connector hardware — shells, cans and contact bodies plated on barrel or rack lines, where the finish is inspected visually and the deposit still has to survive a crimp or a bend without cracking.
• Job shops selling nickel plating services — a shop that changes parts every week needs a brightener that behaves the same in a fresh make-up and in a three-month-old bath, and that repeatability is the usual reason for standardising on one base brightener.
• Brightener formulators and blenders — companies that build their own additive packages buy sodium allyl sulphonate as a component and dose it into their own concentrate alongside their top brighteners and levelers.
• Captive lines inside a plant — where plating is one station in a larger production flow and a stalled tank costs the whole schedule, a base layer that does not drift is worth more than a marginally brighter one.
• Where it is not the answer — electroless nickel plating deposits nickel by chemical reduction and runs a different additive set; if that is your process, tell us and we will point you to the right product instead.

Lot Testing and Changeover

1. Do not drain the bath to try a new lot. On an electro nickel plating line the bath is the asset, so keep it running on what you have while the delivery is evaluated; a changeover made on paperwork alone is how a balanced bath ends up chasing its own tail.
2. Check the delivery against the specification first: clear, colourless to yellowish liquid, density 1.20–1.26 g/cm³, pH 6.5–9.0. Anything outside that range should be raised with us before the drum goes anywhere near a tank.
3. Run a Hull cell panel with the new lot beside a retained sample of the lot you are running now: same bath, same current, same time. Two panels side by side are the only comparison that means anything.
4. Make a working trial on real parts. Bring up a pilot volume, add the product at your normal working level, and plate a rack of production components rather than coupons.
5. Judge it on what a customer sees: brightness across the rack, coverage in the recesses, adhesion after a bend, and whether the next step still takes evenly over the new deposit.
6. Release to production only when panels and parts match, and keep a retained sample of the new lot next to your log so a question months later has something to be checked against.
7. If it does not match, tell us what you saw: panel appearance, bath numbers, and anything else that changed at the same time. That is what our technical team needs to work out whether the cause sits in the lot, the bath or something else in your metal plating process.

Ordering and Delivery

Related Plating Lines

Most plants that buy sodium allyl sulphonate run more than one finishing line. Fengfan covers the zinc side with Brightener for SZ-30B Sulfate Zinc Plating, Bright Zinc Alkaline for Rack and Barrel Plating ZN 50 and Brightener for Cyanide Free Alkaline Zinc Plating ZN-500. The tin side is served by Phoenix EB 204A-204B Divalent Tin Salt Electrolytic Coloring Additive, and the aluminium side by Phoenix Seal 149-L Middle Temperature Sealing Agent for Aluminum Anodizing and Phoenix Seal 149-T Medium Temperature Sealing Agent. On the copper side there is the FI-970 Bright Acid Copper Plating Process.

Nickel has its own line-up: Nickel Purify P3 for bath purification, and the Environmentally Friendly Chrome Mist Inhibitor FF-116 for the chrome line next door. For electroless nickel plating the equivalents are the EN 6786 high-phosphorus process, FF-607 medium phosphorus and FI-E300 for plastic substrates.

FF-4219, the wood, stone and concrete nano-protective, rounds out the range for shops that also do architectural work. Shops offering nickel plating services usually buy across two or three of these lines at once, because the additive logic repeats from one bath to the next.

Batch Documentation

• Every drum is supplied with an inspection certificate issued after delivery, stating the batch number and the warranty period for that batch. Keep it with the receiving record so the material in the tank can be traced back to the drum it came from.
• The specification sheet lists the values a customer or inspector can check: chemical name sodium allyl sulphonate, CAS 2495-39-8, molecular formula C3H5O3NaS, molecular weight 144.12, concentration ≥25.0%, pH 6.5–9.0 and density 1.20–1.26 g/cm³.
• A safety data sheet is prepared for the destination market. Tell us the delivery country when you order so the correct language and format version travels with the shipment.
• If a customer cites a specific regulation or asks for a particular declaration, send us the exact wording they need. We will confirm what can be documented for the grade and batch you receive, and what cannot.
• We do not put a compliance mark or declaration on this grade unless the paperwork for that shipment supports it. A document we cannot stand behind is worse for your customer relationship than no document at all.
• For incoming inspection, the drum label, the batch number on the certificate and the retained sample should match. Store them together so a question raised months later can be answered from the same batch.
• Ask for any additional paperwork before the order is released. Extra documents take time and may depend on the destination, so they are better arranged with the order than after the drum has arrived.

Technical Support & Model Matching

Choosing the right match is where most sourcing decisions stall. As a trading supplier, we keep one point of contact from first enquiry to after-sales: tell us what you are making and the conditions you work under, and we shortlist the closest matches from our supplier network, compare specifications and arrange samples before you commit to a bulk order. If something does not behave as expected, we work with the supplying partner on the cause and a practical fix, and stay with the case until it is settled. Email, WeChat or WhatsApp enquiries get a reply within 24 hours.

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