Textile Sizing Agent

PAM for Textile Sizing

Acrylamide-based polymers appear twice in a weaving mill, and the two roles are easy to confuse because both get called "PAM". In the size box, an acrylic co-binder blended with PVA or starch improves adhesion to synthetic and blended warps. In the effluent plant, high molecular weight PAM flocculates the desizing liquor that the same mill later has to treat. The second role is where most textile mills actually spend money on polymer, and the two use completely different grades.

One correction before the specifications, because it shapes every expectation downstream. Size does not strengthen fibre. It forms a film on the yarn surface that resists abrasion from the reed, heald eyes and drop wires during weaving. Yarn tensile strength is set by the spinning process and is unchanged by sizing. A supplier claiming a polymer improves fibre strength is describing a mechanism that does not exist, and the practical consequence is that a mill with a genuine yarn quality problem cannot size its way out of it. We supply both the acrylic co-binder grades and the effluent flocculants from our own plant in Xinxiang, Henan, with 100,000 tons/year of PAM capacity.

Two Different Products, Two Different Duties

The two also fail in ways that look nothing alike, which is the fastest way to tell which one you are dealing with. A size box problem shows up on the loom and in the weaving shed data — breaks, stops, size shedding as dust around the reed, tack on the drying cylinders. An effluent problem shows up in the discharge monitoring — turbidity, colour, chemical oxygen demand, sludge tonnage leaving site. If the symptom is in the weaving shed, no flocculant will help it; if the symptom is at the outfall, no size recipe will fix it quickly, because the load is already in the water.

Mills enquiring about "PAM for textile" usually want the second column and describe it as the first. Decide which problem you are solving before comparing quotes, because a price per tonne means nothing across two products consumed at doses three orders of magnitude apart. The effluent side is covered in depth in PAM for textile wastewater.

Where PAM Fits in a Size Recipe

A warp size is a formulation, not a single chemical. Starch is cheap and sizes cotton well but adheres poorly to polyester. PVA adheres well to synthetics and gives a tough film but costs more and is harder to treat in effluent. Acrylic copolymers sit between them: good adhesion to hydrophobic fibre, a flexible film that resists shedding, and easier removal in desizing than PVA.

The practical role is 5-15% of total size solids, blended with starch or PVA rather than used alone. At that level the acrylic component fixes the specific defects the base size has — brittleness on a starch-heavy recipe, poor polyester adhesion on a blend — without carrying the whole film-forming load. Going much above 15% raises cost faster than it raises performance and can make the film tacky at the drying cylinders.

The unit basis matters. Size dosing is a percentage of size solids in the recipe, and the size add-on itself is typically 8-14% on yarn weight for cotton warps and 6-10% for polyester blends. Anyone quoting a textile size dose as kilograms per tonne of fibre has conflated the recipe fraction with the add-on and the resulting number will be wrong by a wide margin in either direction. Confirm which basis a quotation uses before you compare two of them.

Grade Selection

The first row is deliberate. If you weave coarse cotton on a well-set loom with a sound starch recipe, an acrylic co-binder is a cost with little return, and we would rather say so than sell into it. The case is strongest on polyester-rich warps, where starch simply does not adhere and the alternative is a higher PVA load that costs more upstream and more downstream in effluent treatment. Full specifications for the effluent grades are on our anionic polyacrylamide and cationic polyacrylamide pages, and the choice between them is set out in anionic vs cationic polyacrylamide.

Desizing Is the Downstream Cost Nobody Budgets For

Every kilogram of size applied to warp yarn is removed again before dyeing, and it leaves in the water. Desizing liquor is one of the highest chemical oxygen demand streams in a textile mill — often the single largest contributor to plant load — because it contains essentially all the size solids the mill paid for, now dissolved or dispersed. Nothing is consumed in weaving; the size is simply relocated from the yarn to the effluent plant, which is why desizing load tracks size add-on almost one for one.

That connects the size box decision to the effluent budget in a way that quotations rarely show. A recipe change that reduces size add-on by two percentage points on yarn weight cuts both the size purchase and the desizing load. A recipe change that swaps easily-removed starch for a tough PVA film improves weaving and makes desizing harder, needing hotter water, more enzyme or oxidative treatment, and leaving a load the biology handles less readily. Neither direction is automatically right; the point is to cost both ends before deciding.

On the treatment side, desizing liquor responds to coagulation followed by high molecular weight PAM. Because much of the load is dissolved rather than suspended, flocculation clarifies the water while removing less COD than the improvement in appearance suggests — the same distinction that governs starch recovery in paper mills. Run a filtered COD test to establish the split before sizing equipment, and treat polymer as the polishing step on the particulate fraction rather than the answer to the whole load. Dose selection arithmetic for that duty is in our dosage calculation guide, and bench screening follows the jar test procedure.

Worked Example: Where the Loom Efficiency Gain Comes From

Modelled from process arithmetic, not a delivered project. A loom running at 85% efficiency on a polyester-cotton warp with 2.5 warp breaks per hundred thousand picks is losing most of the gap to stop time — every break costs the stop, the mend and the restart. Efficiency is arithmetic on break frequency, not a separate variable.

If poor polyester adhesion is what is causing those breaks, adding an acrylic co-binder at 10% of size solids addresses the actual mechanism, and bringing breaks toward 0.8 per hundred thousand picks moves efficiency into the low to mid nineties. That is where a figure around 10-12% more output comes from.

The conditional is the whole point. If your breaks come from loom setting, reed condition, shed timing, humidity in the weaving shed or upstream yarn irregularity, changing the size recipe will not move them, and the polymer will look like it failed. Before budgeting a size change, classify a shift of stops by cause. A mill that finds its breaks are mechanical has just saved the cost of a chemical trial and identified a cheaper fix.

Preparation and Application Practice

1. Cook the base size first, then add the acrylic component. Starch needs full gelatinisation at 90-95°C; adding the co-binder into an incompletely cooked starch paste gives uneven film.
2. Hold the size box at 60-70°C and control solids, not just temperature. Add-on drifts with both. Check refractometer solids every shift rather than trusting the make-down recipe.
3. Avoid high shear in transfer. Chain scission reduces film strength invisibly. Use gentle circulation rather than a high-speed centrifugal loop on a size mix containing high molecular weight polymer.
4. Watch the drying cylinders for tack. Excess acrylic content shows up as size picking up on the cylinder surface before it shows up in weaving data. That is the signal to reduce the share, not to raise cylinder temperature.
5. Test desizing before committing a recipe. A film that weaves beautifully and will not desize at your existing wash temperature has moved cost, not removed it.
6. Hold your supplier to batch consistency. We test every batch for molecular weight to a ±0.5M tolerance and retain samples for 24 months, so when film behaviour shifts we can compare your drum against the retained sample and establish whether the polymer or the process changed. Why chain length matters is set out in our molecular weight guide.

Standards and Test Methods We Work To

Size performance and effluent compliance are judged against published methods rather than supplier claims. For yarn and fabric testing, ASTM International and ISO both publish the tensile, abrasion and size add-on methods used across the industry, and AATCC publishes the wet processing and desizing evaluation methods most mills reference. For the effluent side, chemical oxygen demand, suspended solids and colour follow the methods in Standard Methods for the Examination of Water and Wastewater, published jointly by the American Public Health Association, the American Water Works Association and the Water Environment Federation. Mills supplying brands with chemical restrictions are usually working to the ZDHC Manufacturing Restricted Substances List, and we supply batch documentation that lets you demonstrate conformance rather than assert it.

We do not print method designations on this page. Numbers get revised, and a stale designation quoted with false precision is worse than a named body you can verify. Tell us the specific test in your specification and we will confirm the current designation in writing.

Frequently Asked Questions

Does PAM increase yarn strength?

No. Size forms a protective film on the yarn surface that resists abrasion during weaving; it does not change the tensile strength of the fibre, which is set in spinning. If your problem is genuinely weak yarn, sizing will not fix it. If your problem is breakage from abrasion at the reed and healds, sizing is exactly the right lever.

Can I use PAM as the only sizing agent?

Not economically. Acrylic and acrylamide copolymers work as a co-binder at 5-15% of size solids alongside starch or PVA, fixing adhesion to synthetics and film brittleness. Used as the whole recipe the cost rises faster than performance and the film can become tacky at the drying cylinders.

Is the dose quoted per tonne of fibre or as a percentage?

As a percentage of size solids in the recipe, with size add-on itself typically 8-14% on yarn weight for cotton and 6-10% for polyester blends. A quotation expressed as kilograms per tonne of fibre has confused the recipe fraction with the add-on, and the number will be badly wrong. Check the basis before comparing prices.

Will switching to an acrylic co-binder make desizing harder?

Generally easier than a high PVA load and harder than pure starch. Acrylic films are removed with warm water and standard desizing chemistry, whereas PVA needs hotter water and more aggressive treatment. Test desizing at your existing wash temperature before committing, because a film that weaves well and will not come off has moved your cost downstream rather than removed it.

Which product do I need for my dyeing and desizing effluent?

A completely different one — high molecular weight APAM or CPAM at 1-8 g/m³ behind a coagulant, not a size-box grade. Run a 0.45 micron filtered COD test first: flocculation removes the particulate fraction, and if most of your load is dissolved the water will look much better while COD moves little. Size that expectation before buying equipment.