Functional finishes are chemical finishing treatments that add a performance property to base knitted fabric without altering its fibres. Antibacterial/antimicrobial, UV protection and water-repellent finishes are the three most requested members of this family. This guide explains how each one works, the durability to expect and the selection of certified chemistry; rather than numerical commitments, it highlights the right questions to ask. For the wider context, see the functional finishing guide, and for moisture management see the moisture management and wicking page.
How does antimicrobial finish control odour, does it sterilise the fabric?
Odour does not come from sweat itself but from the metabolic products of micro-organisms that feed on sweat and sebum. Antimicrobial finish delays this process by limiting the growth of the microbial population on the fibre surface. In practice this creates a perception of "two-days-in-a-row wearability", particularly in activewear and frequently worn t-shirts/underwear. An important distinction: the finish provides antibacterial odour control; a claim of disinfection or disease prevention in the medical sense is a separate regulatory domain and requires care in labelling.
The chemistries fall roughly into two groups. Leaching systems slowly release the active agent; bound (non-leaching) systems bond covalently to the fibre and stay in place. The silane-based quaternary ammonium chemistries widely used in textiles are an example of the second group and generally offer better wash durability with a low migration profile. Zinc pyrithione and silver-based systems are also used; each has a different certification and ecological profile. The choice of active agent should always be made on the basis of ZDHC MRSL and OEKO-TEX compliance; biocidal active substances must additionally be on the approved list under the EU Biocidal Products Regulation (BPR).
Efficacy is measured by standard methods: AATCC 100 (quantitative bacterial reduction), AATCC 147 and ISO 20743 are common. As a buyer, ask the supplier which standard, against which micro-organism and after how many washes the test was carried out; "antibacterial" on its own is not a complete specification.
How does UV protection finish work, what does the UPF value mean?
A fabric's UV protection comes largely from its physical structure: high weight, tight construction, dark colours and fibres such as polyester that absorb more UV naturally provide higher protection. A light-coloured, thin, loosely knitted single jersey gives lower protection than the dark/high-weight version of the same fabric. UV finish raises this base barrier by adding UV-absorbing/scattering molecules to the fabric, making a particular difference in light-coloured or thin fabrics.
The UPF value is determined by standard test; the most common are AS/NZS 4399 and AATCC 183. The critical point here is the numerical commitment: the UPF value changes with the fabric's colour, weight, stretch (extension), wetting and wash state. Fabrics with elastane, such as leggings, open up when stretched and the effective protection can fall; wet fabric can also behave differently. For this reason, before committing to a particular UPF figure on the product, the correct approach is to have it tested on the final fabric and colour. Let us clarify together the target UPF class and test conditions.
What is the difference between a water-repellent (hydrophobic) finish and waterproof?
A water-repellent finish coats the fibre surface with a low-surface-energy layer so that water forms beads instead of spreading; this effect is known as DWR (Durable Water Repellent). Because the fabric pores remain open, breathability is preserved, which is important in knitted activewear. Waterproofing, in contrast, is a much higher performance level that withstands a specific water-column pressure (hydrostatic head) and usually requires a membrane/lamination. Confusing the two is a common purchasing mistake; whether the need is "light rain/splash resistance" or "full sealing" should be established from the outset.
On the chemistry side, the most important current issue is the fluorocarbon question. Traditional long-chain C8 fluoropolymers fall into the PFAS group and are being rapidly abandoned due to REACH restrictions and brand policies. The preferred direction today is PFAS-free (non-fluorinated) chemistries; these are generally dendrimer, paraffin/hydrocarbon or silicone-based systems. PFAS-free systems may fall short of fluorocarbons in oil repellency performance; for pure water-repellency needs, however, they are sufficient in most applications. The choice of chemical must comply with ZDHC MRSL and the brand restricted substances list (RSL).
Water-repellent performance is generally graded by spray test (AATCC 22 / ISO 4920); additional methods such as rain test and absorption time also exist. Here too, the final fabric must be tested before giving a figure, because performance is sensitive to the construction type, pre-treatment residues and curing conditions.
How should the comparison of finish, function and wash durability be read?
The table below summarises the three finish families in terms of function, typical chemical orientation and durability logic. The durability statements in the table are relative; exact wash durability must always be verified by the final recipe and testing.
| Finish | Function | Durability note |
|---|---|---|
| Antimicrobial (odour control) | Suppresses the growth of odour-causing bacteria; odour comfort over repeated wear | Bound (non-leaching) chemistries are generally more durable; leaching systems weaken faster with washing |
| UV protection (UPF) | Reduces UV transmission; reinforces the natural barrier in light-coloured/thin fabrics | Colour, weight and construction are the primary protectors; the finish contribution can decrease with washing and stretch |
| Water-repellent (DWR / hydrophobic) | Water beads, absorption is delayed; breathability is preserved | Decreases with mechanical abrasion and washing; can be partly restored by reactivation (ironing/heat) |
There are common factors that determine durability. The first is the quality of curing: the right temperature-time combination is needed to fix the finish chemistry to the fibre; insufficient curing leads to early wash-out. The second is pre-treatment cleanliness; if size, oil or residual finish remains on the surface, the new finish cannot adhere. The third is the active-agent chemistry; systems that bond covalently to the fibre last longer than systems that merely sit mechanically on the surface. For the quality testing framework, see the quality and testing guide and the colour fastness pages.
Which certifications are mandatory for functional finish chemicals?
On the certification side, three layers are assessed together. Process input layer: the chemicals used must be ZDHC MRSL (manufacturing restricted substances list) compliant; where possible, products registered on the ZDHC Gateway with a higher conformance level should be preferred. Product output layer: the finished fabric meeting OEKO-TEX Standard 100 limit values is the basic reference for consumer safety. Active-substance layer: for antimicrobial biocides, EU BPR and the relevant market legislation, and for water-repellents the PFAS/REACH-SVHC status, should be tracked especially closely.
The table below summarises the certification and compliance focus points for the three finishes.
| Finish family | Process / chemical compliance | Product / regulatory focus |
|---|---|---|
| Antimicrobial | ZDHC MRSL compliant active agent; bound-type preferred | OEKO-TEX 100; BPR-approved list for biocidal active; efficacy test (AATCC 100 / ISO 20743) |
| UV protection (UPF) | ZDHC MRSL compliant UV-absorbing chemistry | OEKO-TEX 100; UPF test (AS/NZS 4399 / AATCC 183) on final colour-fabric |
| Water-repellent (DWR) | PFAS-free (dendrimer/paraffin/silicone) preferred; ZDHC MRSL compliance | OEKO-TEX 100; REACH PFAS restriction and brand RSL; spray test (AATCC 22 / ISO 4920) |
A practical checklist for a B2B buyer: (1) At which conformance level is the active agent on the ZDHC MRSL? (2) Is there an OEKO-TEX or equivalent report for the finished fabric? (3) Is the water-repellent PFAS-free, and is it compliant with the brand RSL? (4) Under which standard and after how many washes was the function test carried out? (5) Has the numerical target for UPF/odour/water-repellency been verified on the final fabric? These five questions close off most functional finish supply risks at the outset. Our certification scope and our knit-dye-print processes are aligned with this framework.
Which finish is the right choice for which product?
Priority changes according to the product scenario. In legging and activewear fabrics, antimicrobial odour control and moisture management are often required together; in that case compatibility with the wicking finish must be considered. In outer layers such as sweatshirt/hoodie, a water-repellent finish is meaningful for splash resistance. In light-coloured summer t-shirts and sportswear, a UPF contribution adds value where the natural barrier is weak.
Multiple finishes (for example antimicrobial + water-repellent) are possible in a single bath, but the compatibility of the chemicals with each other and with the base fabric's pre-treatment must be tested; some combinations can adversely affect adhesion or handle. In addition, since every extra finish can have an effect on fastness, dimensional stability and handle, the basic quality parameters must be re-verified when adding a function. The right recipe is determined by assessing the target performance together with the commercial constraints (colour, fabric, certification expectation).
Frequently asked questions
Does an antimicrobial finish sterilize the fabric, or does it only control odor?
It does not sterilize. An antimicrobial finish suppresses the growth of odor-causing bacteria that feed on sweat and sebum at the fiber surface, thereby delaying odor formation; the goal is odor comfort over repeated wear. This is odor control. Disinfection in the medical sense or any disease-prevention claim falls under a separate regulatory domain and requires care in labeling.
By which test standards is antimicrobial efficacy measured, and what should I request from the supplier?
Common methods are AATCC 100 (quantitative bacterial reduction), AATCC 147 and ISO 20743. "Antibacterial" on its own is not a complete specification. Ask the supplier which standard was used, against which microorganism, and after how many wash cycles the test was run. The active agent should also be ZDHC MRSL and OEKO-TEX compliant, and biocides must appear on the approved EU BPR list.
What does the UPF value indicate, and can we commit to a specific UPF figure on the product?
UPF indicates how much UV radiation the fabric blocks; UPF 50 roughly means that only 1/50 of the UV passes through. Protection varies with color, weight, stretch, wetting and washing; when elastane fabric is stretched the knit opens up and protection can drop. For this reason, before committing to a figure, testing on the final fabric and color per AS/NZS 4399 or AATCC 183 is required.
Is a water-repellent (hydrophobic) finish the same as waterproof?
No, they are different performance levels. A water-repellent (DWR) finish lowers surface energy so that water beads up and rolls off instead of being absorbed; the fabric remains breathable. Waterproofing, on the other hand, is a far higher performance that withstands a defined hydrostatic pressure and usually requires a membrane or lamination. Confusing the two is a common purchasing mistake; the requirement should be clarified at the outset.
Why must a water-repellent finish now be PFAS-free?
Traditional long-chain C8 fluoropolymers fall within the PFAS group and are being rapidly phased out due to REACH restrictions and brand policies. The preferred direction is PFAS-free chemistries; these are typically dendrimer, paraffin/hydrocarbon or silicone-based. PFAS-free systems may be limited in oil repellency, but for pure water repellency they are sufficient in most applications. The choice must comply with ZDHC MRSL and the brand RSL.
What determines the wash durability of a finish's performance?
All three finishes weaken with washing; durability depends on cure quality, pre-treatment cleanliness and the chemistry of the active agent. Systems cured at the correct temperature and time, with surfaces free of size and oil residue, and covalently bonded to the fiber (bound/non-leaching) last longer. A DWR finish can be partially reactivated with ironing or heat. Before committing to a specific number of washes, post-wash testing on the final fabric is required.