Modal Underwear Manufacturer

Renrui makes private label modal underwear from 100 pieces per colour, with sizes split freely inside that quantity. Most modal boxer brief specs we are asked for use a 92/8 micromodal or 91/9 modal jersey at around 180 gsm. Samples take 7–10 days, bulk takes 25–35 days after sample approval, and reorders ship in 10–15 days.

Fabric is pre-shrunk to within 3% before cutting, and quotes go out within 8–12 hours of a complete inquiry.

This page covers modal-specific production. For our full underwear range, styles and construction, see our custom underwear manufacturer page.

Modal, micromodal, lyocell and bamboo viscose are all regenerated cellulose fibres, and on a quote they can look interchangeable. On the cutting table they’re not. Fineness, hand feel, weight and the finishing each one needs before cutting are all different.

Sources: fibre fineness — Tomljenović & Živičnjak, Nanomaterials (2025); moisture regain — Morton & Hearle, Physical Properties of Textile Fibres (2008). A dash means we haven’t found a reliable published figure.

Yes. It is one of the things modal buyers ask us about most. Modal drapes instead of bunching, which is exactly what a pouch wants. We build three.

The catch: modal is light and slippery, and if you cut and sew it like cotton, the pouch seams pucker. We cut pouch panels in low ply heights, sew the pouch with a stretch stitch at a shorter stitch length, and line 3D and U-pouches with self fabric so they keep their shape after washing.

More panels means more sewing time: a separated U-pouch usually adds 10–20% to the unit price over a contour front.

This is the spec sheet for a modal underwear order. Everything below is standard for us — pick what you want and it goes into the same quote.

If you would rather not decide, copy the spec most first orders arrive on: a 5–6″ boxer brief in 92/8 micromodal, no fly, a 3.5 cm exposed waistband with a heat-transfer logo, sizes S–XXL. It sells, and it is cheap to reorder — which is the whole point of a first drop.

Most modal underwear isn’t 100% modal. The elastane is what pulls it back into shape after it’s stretched, and a couple of points either way changes the feel more than most people expect.

Brands that ask us for modal underwear most often specify 92/8 micromodal or 91/9 modal at around 180 gsm. Go past about 10% elastane and it stops feeling like modal and starts feeling like gym kit.

Yes. They run on the same lines as the boxer briefs, on the same pre-shrunk, wash-tested fabric, at the same 100 pieces per colour.

• Styles: briefs, bikinis, hipsters and high-waist briefs, in full or moderate coverage.
• Edges: picot elastic, covered elastic or raw-edge finishing.
• Gusset: lined to your spec; a 100% cotton gusset lining is the most common request.
• Lace: lace trim or lace waistbands where the design calls for it.

A typical women’s spec we are asked to quote: 92/8 modal/elastane at about 180 gsm, mid or high rise, cotton gusset, woven main label and care label, three colours, sizes XS–XXL. If you only have a reference garment, our pattern room can draft the block from it.

Modal is a high wet modulus rayon. It holds its shape better than ordinary viscose, but an untreated modal knit still shrinks badly in its first wash. How badly comes down to one thing: how the fabric was finished before anyone cut it.

So the same modal yarn can lose almost a fifth of its length or almost nothing, depending on whether the fabric was relaxed and compacted before cutting. That’s why a “modal” spec on its own tells you very little, and why we test every production roll.

Here’s what we actually do on every modal order: a swatch is cut from the actual roll your order will be cut from, washed and dried on a repeated domestic cycle following ISO 6330, and dimensional change is read the AATCC 135 way. You get the length and width figures before we cut your bulk. If the roll drifts from what your approved sample did, we change the roll, not your spec.

Figures from published studies are for reference and vary with knit structure, weight and finishing. Your order’s own results are sent to you before bulk.

This is the next thing buyers ask about after shrinkage, and they are right to ask. Modal is a fine, smooth fibre. Where fabric rubs on fabric — the inner thigh, the seat — loose fibre ends work up into pills. Hot tumble drying makes it far worse.

Four things decide how long a modal boxer brief lasts.

• Yarn and weight. Compact-spun micromodal at the heavier end of its range, 170 gsm and up, holds up far better than open, light jersey under 150 gsm. If a quote looks cheap, check the fabric weight first.
• The gusset. We sew a double-layer gusset on briefs and boxer briefs as standard, so the area that wears through first has two layers.
• Pilling test on request. We can have your fabric tested to ISO 12945-2 (Martindale). A well-made micromodal jersey typically rates grade 3–4 on the 1–5 scale after 2,000 rubs. Below grade 3 we would not recommend it for underwear.
• The care label. We print “machine wash cold, tumble dry low or hang dry” by default, because most of the pilling customers complain about starts in the dryer.

For a first run of 100–300 pieces per colour, most brands start with stock elastic and a printed or woven logo, then move to a custom jacquard waistband once reorders justify the elastic minimum.

Whichever you choose, the waistband is joined with a four-thread overlock and bar-tacked at the side seams, so it doesn’t split at the join after the first wash. Elastic minimums are set by the elastic mill; we confirm the exact figure for your design when we quote.

Custom packaging starts at 100 per design, same as the garments. So yes, a first drop of 100 boxer briefs can go out in your own branded box. We print it while your bulk is being sewn and pack it on the same line, and the cartons leave here retail-ready.

Send your dieline and artwork, or tell us the size and finish you want and we set up the dieline for you. We send a photo of the packed sample before bulk, so you see the folded garment in the box, and the barcode or SKU stickers you send us go on every unit before cartoning.

Five questions, all specific to modal. You can ask every one of them in a single email — of us, or of anyone else you are quoting.

1. Ask what “modal” means on the quote. It can mean branded fibre (such as Lenzing™ Modal) or generic modal. Generic modal is what most private-label programmes use. What matters is that the quote says which, and that you get the blend ratio and fabric weight in writing.

2. Ask for wash results on the actual roll. Modal and micromodal behave well in a showroom sample and then shrink in a customer’s dryer when the fabric was never pre-shrunk. A factory that can’t show you a number hasn’t tested.

3. Check the waistband, not only the body fabric. Most modal underwear complaints are about a waistband that relaxes after a month, not the modal itself. Ask how the elastic is attached and what its recovery is after washing.

4. Ask how they cut a light, slippery fabric. Micromodal moves on the cutting table. Ask whether they cut it in lower ply heights or under weights. Uneven cutting shows up later as twisted side seams.

5. Ask what the minimum is per colour, and whether that colour is dyed for you. Modal is dyed in fabric lots, and some low minimums only work because the factory is cutting stock fabric in whatever colours already exist. Ask which it is. With us, the 100 pieces per colour are dyed to your Pantone reference, not picked from a stock colour card.

• TENCEL™ and LENZING™ are Lenzing AG trademarks. Using fabric made from the fibre doesn’t by itself let you print the name on your hangtag or packaging; brands apply through Lenzing’s licensing programme. The lyocell we stock is generic lyocell, so it is labelled “lyocell” on care labels and product copy, not TENCEL™.
• Bamboo has to be labelled as rayon or viscose in the US. Under FTC rules, underwear made from bamboo-based viscose must be described as “rayon made from bamboo” or “viscose from bamboo”, not as “bamboo fabric”. We label it that way on care labels by default. The same rules apply to our bamboo sleepwear.
• Fibre content goes on the care label by percentage, for example “92% Modal, 8% Spandex”, with country of origin “Made in China”.
• OEKO-TEX® Standard 100: our modal, micromodal, lyocell and bamboo-viscose fabrics are certified, and certificate copies travel with every shipment.

A few real specs from recent inquiries (brand names left out):

• Men’s boxer briefs, 91/9 modal at 180 gsm, quoted at 300, 500, 1,000 and 1,500 pieces
• 5-inch boxer briefs in 92/8 micromodal, 300 pieces, with retail packaging
• Men’s boxers in modal or lyocell, 300–400 pieces, three-packs in a magnetic gift box
• Cotton/modal/spandex boxer briefs at 190 gsm with a jacquard waistband

If your spec looks like one of these, include the fabric ratio, weight, waistband type and quantity per colour in your inquiry, and we can quote without a back-and-forth.

Send the style, fabric and blend ratio, weight, waistband type and quantity per colour. We quote within 8–12 hours and flag anything outside our standard range in the first reply.

We confirm the fabric lot, pre-shrink it to within 3%, and run the ISO 6330 wash test on a swatch from the roll your order will use. You see the figures before cutting.

One sample per style, sewn in-house by the same line that runs bulk. Turnaround 7–10 days; the sample fee is credited against your bulk order in proportion to the bulk quantity.

25–35 days after sample approval and deposit. Finished garments are measured against your size chart within ±1 cm on body measurements and ±0.5 cm on the waistband. AQL 2.5 final inspection; bulk that drifts from your approved sample is remade, not shipped. FOB Shanghai or Ningbo, or DDP door-to-door.

Everything up front, so you don’t have to email three times to find it.

What the 100-piece minimum does and doesn’t cover:

Which brands we fit best:

• New brands on a first drop: 100–300 pcs per colour, stock elastic with a printed or woven logo, one colour in a full size range.
• Subscription and 3-pack brands: reorders in 10–15 days off a held spec, so the second shipment matches the first.
• Premium and pouch lines: 92/8 micromodal, 3D or U-pouch construction, and a custom jacquard waistband once reorders justify it.

Names are withheld at the clients’ request.