WhatsApp : (+86) 19058080181 Email : info@vi-tex.com
Proban Process for Cotton: Flame Retardant Finishing and Testing
The Proban process for cotton adds durable flame resistance to cotton fabric through a licensed finishing route. The treatment forms a cross-linked polymer within the cotton fibre structure. Untreated cotton remains combustible, so buyers need to assess the finished fabric and its test records against the intended garment and end use.
A process name on a quotation does not confirm how a fabric will perform. Construction, weight, shade, washing conditions and the required flame test all affect approval. We check the sample after finishing and after the agreed wash cycle, because the fabric may change in handle or strength during processing.
What the Proban process does to cotton
PROBAN® uses SNF-licensed chemistry to form an insoluble polymer within cotton fibres. When flame reaches the fabric, the phosphorus-based system helps form an insulating char that slows heat transfer and flame spread. The treatment becomes part of the finished fibre structure rather than sitting as a film on the fabric surface.
Some technical descriptions of the route refer to a THPC-based precondensate followed by ammonia treatment. The authorised finishing plant must confirm the actual formulation and process window. Buyers should ask which plant carries out the treatment and what current approval applies to the order.
Terminology can cause confusion when buyers compare treated cotton with inherently flame-resistant fibres. Untreated cotton is combustible. SNF describes the polymer in PROBAN-treated cotton as permanently bound within the fibre and explains its classification on that basis. The useful comparison is the finished fabric’s test record, care instructions and suitability for the hazard.
How the Proban finishing route works
The production route includes several controlled stages. Each finishing plant must use the settings and safety procedures that apply to its licensed process and equipment.
- Fabric preparation. The plant checks fibre content, construction, weight, width and pretreatment. Uneven absorbency or residues can affect treatment coverage.
- Padding. The fabric passes through the treatment bath and padding rollers. Operators monitor wet pick-up across the width and along the roll.
- Pre-drying. The line removes moisture before the curing stage. Uneven drying can affect the reaction and create differences between the fabric edges and centre.
- Ammonia curing. The fabric enters the controlled ammonia stage, where the licensed chemistry forms the cross-linked polymer. This step requires suitable equipment and trained operators.
- Oxidation and washing. The plant follows its approved sequence to stabilise the finish and remove residual chemicals.
- Final finishing and inspection. The plant controls the fabric’s dimensions and checks its appearance, weight, handle, strength and flame performance.
A setting from one line should not be copied to another. A lightweight jersey and a dense twill absorb and release moisture differently. Fabric width, line speed, construction and equipment also affect the result. Ask the finishing plant to identify the source and operating basis for any process figure it shares.
What buyers should test before bulk production
Agree on the test method and acceptance limits before approving a sample. “Passes a flame test” is incomplete unless the supplier identifies the method, specimen condition and whether the lab tested the fabric before or after laundering.
- Flame spread: Name the required test and ignition procedure. ISO 15025:2016 covers limited flame-spread testing on vertically oriented flexible materials. It does not assess every thermal hazard or replace the relevant protective garment standard.
- Wash durability: Record the wash count, temperature, detergent, bleach policy, drying method and conditioning period. Domestic washing and industrial laundering do not produce interchangeable results.
- Strength: Compare tensile strength and, where relevant, tear strength before and after treatment and laundering. If a project sets a maximum strength loss, such as 10%, state the test method and sample condition beside that limit.
- Handle and weight: Check stiffness, drape, surface feel and fabric mass. A result from one fabric weight does not predict the handle of another construction.
- Dimensional stability: Measure length, width, skew and shrinkage after the agreed care cycle. Pre-shrinking can help with garment dimensions, but the buyer should still measure the finished fabric.
- Colour: Check the dye class, shade reference and finishing order. For a critical shade, approve a lab dip and a trial roll after finishing.
Link every result to the fabric construction and production lot. A report for a different weight, shade or finish route cannot confirm the sample under review.
How we review samples in our sample room
We place an untreated control beside a treated swatch and a treated swatch after the wash cycle specified for the project. That side-by-side check makes changes in appearance and handle easier to see. The untreated piece gives us a reference, while the washed piece shows what happened during the agreed care test.
We keep the fabric reference with its construction, shade, finishing route and test condition. When a trial roll is needed, its report should identify the roll and lot that the lab tested. This detail helps the buyer compare the approved sample with later bulk production.
A softer-hand target or a strength-loss limit should have a clear basis. If the buyer asks for no more than 10% strength loss, the specification should name the test direction, wash conditions and acceptance rule. We do not present that figure as a universal result for every Proban-treated fabric.
What a 50-wash claim means
A wash count only has meaning when the writer identifies the laundering method and the fabric under test. SNF describes a PROBAN label process in which samples from production batches undergo at least 50 industrial washes and 50 dries before flame-spread testing. The result applies to that specified process and certification route.
Buyers should ask whether the fabric they are evaluating has a current report for the relevant construction and intended use. They should also follow the garment maker’s care instructions. A number by itself does not show whether the sample passed the required test.
For more detail on the licensed route and its batch-testing process, see SNF’s PROBAN process information.
Check chemical compliance separately
Flame performance and restricted-substance testing answer different questions. A fabric can pass its flame test and still need chemical testing for the destination market. A chemical certificate does not establish protection against a flame hazard.
If formaldehyde is a buyer requirement, ask for a current laboratory result that identifies the tested material, method and limit. General descriptions such as “low formaldehyde” do not replace a report linked to the product being purchased.
Keep the chemical documents with the approved fabric specification and test report. This gives the sourcing team one record to check when the buyer reviews a repeat order or a new production lot.
When treated cotton fits the project
Proban-treated cotton may suit projects that need cotton’s familiar handle and moisture absorption alongside flame-resistant performance. The buyer still needs to test the actual fabric and confirm that the result meets the garment’s requirements.
The route has trade-offs. A finishing change can affect handle, shade, strength and cost. The process also depends on authorised equipment and controlled operation. Ask which plant performs the treatment and which report supports the order before comparing prices.
Some applications call for a flame-resistant fibre rather than a finish on cotton. The two choices suit different fabric constructions and should not be treated as interchangeable. For programmes starting from the yarn stage, buyers can compare 100% meta-aramid dyed yarn for protective fabrics with the required fabric structure and product-specific test evidence.
Details to confirm before requesting a sample
Send the information that defines the sample and its approval test:
- End use, garment type and the hazard the material must address.
- Fibre content, knit or weave construction, fabric weight, width and target shade.
- Required flame test, wash method, cycle count and drying conditions.
- Strength, dimensional stability, handle and colour limits.
- Destination market and chemical documentation requirements.
- Sample quantity, trial-roll size, expected order volume and timing.
- Authorised finishing route and the report required for final approval.
These details let the buyer compare like with like. An unfinished fabric price is different from the cost of a finished fabric that has passed the specified tests and shade approval. Share the construction and test method with the VI-TEX team before requesting a bulk quotation.
Questions about the Proban process for cotton
Does the finish sit on the fabric surface?
No. SNF describes PROBAN as a cross-linked polymer formed within the cotton fibre structure. Buyers should confirm that the supplier’s test report covers the fabric under review.
Does untreated cotton become flame resistant?
No. Untreated cotton remains combustible. The flame-resistant performance comes from the finish in the treated fabric, so approval must refer to the finished material and its test results.
Does “50 washes” guarantee that every fabric will pass?
No. The wash count must match a stated laundering method, drying condition, fabric construction and flame test. SNF’s PROBAN label process specifies at least 50 industrial washes and 50 dries for production samples before flame testing.