Disposable Sanitary Napkins Explained: How to Read Sizes, Absorbency and Material Specs

Cover: automated disposable sanitary napkin lines — where the millimetres, grams and millilitres on a spec sheet are actually produced.

In short: a disposable sanitary napkin is a single-use absorbent pad built from a liquid-permeable top sheet, a distribution layer, an absorbent core and a liquid-blocking backsheet, held together with adhesive and released on a peel strip. In the Ecolivia range, pad length runs from 155 mm to 450 mm, and the millilitre figure printed as “absorbency” only means something when it is read next to the product category and the test behind it.

Ecolivia is the disposable sanitary napkin brand of Family Cares Group, an integrated hygiene and medical materials manufacturer headquartered in Xiamen, China, with production anchored in the hygiene cluster of Quanzhou and an annual output above 650 million pieces.

The real problem: a spec sheet is written for engineers, not for buyers

Most first-time importers, distributors and new brand owners receive a one-page product sheet and assume the numbers are directly comparable to what they already sell. They usually are not. A napkin spec sheet mixes four different kinds of information in the same table: physical dimensions (mm), material weight (gsm), absorbent capacity (ml) and compliance claims (certificate names). Each one is measured differently and each one can mislead if it is read alone.

Three confusions come up repeatedly in first-year sourcing conversations:

• Length treated as a quality grade. A 410 mm pad is not automatically “better” than a 285 mm pad; it is a different format aimed at heavier flow or overnight use, and it consumes more material.
• Millilitres compared across categories. A menstrual pant rated at 150–300 ml and an adult diaper rated at 1500 ml to 8000 ml+ are both described as “absorbency”, yet they are not on the same scale, are worn differently, and are tested under different conditions.
• Material names used as performance claims. Organic cotton, bamboo fibre, bio-based polymer and breathable bio-film describe what a layer is made of, not how much liquid the finished pad will hold.

The practical consequence is that a buyer cannot evaluate two quotations by comparing their headline numbers. The comparison only works when the same fields, the same units and the same category assumptions are applied to both.

How the category is actually structured

Commercial market research typically splits feminine hygiene into sanitary napkins and pads, panty liners, tampons and other formats, and then separates disposable from reusable products. That segmentation matters for sourcing because each segment has a different material stack, a different regulatory path and a different shelf position.

On the supply side, disposable sanitary napkins are assembled from a small set of industrial inputs: non-woven fabric for the top sheet and side gathers, fluff pulp and super absorbent polymer (SAP) for the core, and either a breathable bio-film or a polyethylene film for the backsheet. Raw non-woven is supplied on rolls across a 10–80 gsm band, and that single raw material stream feeds not only pads but also related hygiene products such as pants and adult care items. Buyers who understand that the raw material is shared across categories stop expecting the finished products to behave the same way.

Environmental questions around the category are now part of sourcing conversations rather than a marketing add-on. Peer-reviewed literature discusses the environmental impacts of manufactured single-use menstrual products, and published lifecycle inventory work covers representative sanitary pad samples. Neither of these establishes a biodegradability percentage for a specific product. That is why environmental positioning should be handled as a documentation request — bill of materials, material certificates, test method — rather than accepted from a catalogue headline.

The four layers, and what each material choice changes

Material converting area: the layers described below are combined in-line at high speed.

1. Top sheet — the layer that touches skin

The top sheet is a non-woven fabric engineered to let liquid pass through quickly while feeling dry afterwards. It is the layer most often linked to softness and skin comfort, and it is the first place where GSM selection changes the finished product: lighter non-woven generally supports a softer hand-feel, heavier grades support structure and strength. For sensitive-skin or hypoallergenic positioning, the top sheet and the absence of added fragrance or chlorine bleaching are the fields to specify, not the absorbency number.

2. Distribution layer — the part buyers forget

Between the top sheet and the core sits a transfer or acquisition layer that spreads liquid sideways so the core can absorb it instead of letting it pool in one spot. It is rarely printed on a retail pack, but it is the difference between a pad that feels dry in the first minutes and one that fails at the edges under a heavy flow.

3. Absorbent core — pulp, SAP, or a bio-based build

The core is where capacity is created. A conventional core combines fluff pulp with super absorbent polymer; the SAP locks liquid into a gel, while the pulp gives the core its shape and wicking structure. Material options that appear on modern spec sheets include FSC-certified wood pulp, chlorine-free organic cotton, bamboo fibre and bio-based polymer, all of which change the story told on pack rather than the physics of absorption.

Core architecture also changes performance. Family Cares Group compares its advanced bio-absorbent core against standard SAP and pulp cores and reports twice the liquid absorption speed, which in practice affects how quickly a heavy-flow pad clears the surface rather than how much total liquid it can hold.

4. Backsheet — breathable bio-film versus PE

The backsheet is the barrier that stops leakage and, in breathable constructions, allows moisture vapour to escape. A conventional polyethylene film blocks liquid and vapour; a plant-based bio-film is designed to block liquid while letting air move. Family Cares Group reports that its plant-based bio-film backsheet delivers a 40% increase in airflow compared with standard PE backsheet products. The trade-off is material cost, which is why bio-film is usually positioned in premium or eco-differentiated ranges rather than entry price points.

What raw-material GSM has to do with the finished pad

Non-woven is bought by weight per square metre, across a 10–80 gsm band, and the same supply base serves sanitary napkins, menstrual pants and adult care products. GSM is fixed long before assembly, so it constrains what a factory can promise later: you cannot ask for a visibly softer top sheet without moving within the non-woven band you have approved. This is why an experienced buyer locks the material specification at sampling stage and treats GSM as a controlled parameter, not a marketing detail.

Sizes: what 155 mm to 450 mm really describes

Pad length is a format decision tied to flow volume, garment fit and wearing occasion. In the Ecolivia-Bio Series, the size range spans 155 mm to 450 mm. The FC-Standard Series is built around four lengths: 240 mm, 285 mm, 330 mm and 410 mm.

A useful way to read the numbers:

• Shortest lengths in the range serve liner-style and light-flow use, where discretion and low profile matter more than capacity.
• 240 mm and 285 mm sit in the everyday regular zone, the volume drivers of most retail ranges.
• 330 mm and 410 mm move into heavy-flow and overnight territory, where length supports coverage at the front and back of the pad.
• Longer formats above 410 mm in the Ecolivia-Bio Series extend coverage further for overnight, postpartum and maternity care programmes.

Two practical rules follow. First, a longer pad is not a substitute for a stronger core; length solves coverage, not capacity. Second, range architecture usually needs two or three lengths rather than six, because shelf space and SKU management cost more than the additional millimetres.

Absorbency: why the number is category-specific

Absorbency is expressed in millilitres, but a millilitre rating is only meaningful inside one product category. In the FC-Pants Series, menstrual pants are rated at 150–300 ml. In the adjacent adult care category, FC-Care Pro adult diapers are rated from 1500 ml to 8000 ml+.

The gap is not a quality gap. It reflects different products: a menstrual pant is a body-fit garment worn for a defined period, while an adult brief is designed for incontinence care, where a single item may need to hold a much larger volume over a longer wearing window and under different test conditions. Family Cares Group’s long-running adult care work with a US medical and adult care brand, spanning more than ten years, includes high-absorbency cores in the 6500 ml+ class with a reported 0% major quality complaint rate — a figure that belongs to adult care and should never be transposed onto a sanitary napkin quotation.

For napkins themselves, the honest position is that capacity depends on the SAP loading, pulp ratio and core architecture per SKU, and should be confirmed by a lab report for the exact product rather than inferred from a family description. Buyers who ask for “the absorbency of the range” get an average; buyers who ask for the test report on the SKU they will actually order get a decision-grade number.

Step-by-step: how to read a sanitary napkin spec sheet

The method below works on any supplier’s document, not only on Ecolivia material, and it is the sequence a distributor can reuse for every new SKU.

1. Fix the category first. Decide whether the line is a sanitary napkin, a panty liner, a menstrual pant or an adult care product. Every later number depends on this.
2. Read dimensions before performance. Confirm length in mm, and check whether width, wing design and pad shape are stated. If wings are not mentioned, assume they are not included.
3. Translate the material stack into layers. Ask which non-woven GSM is used for the top sheet, whether the core is SAP plus pulp or a bio-based core, and whether the backsheet is PE or breathable bio-film.
4. Request the absorbency figure with its test method. A millilitre value without a method and a sample reference is marketing, not specification.
5. Check the pack and case configuration. Pads per pack, packs per case and case dimensions determine freight cost per unit as much as the FOB price does.
6. Match compliance documents to the exact site and SKU. A certificate covering a different factory or a different product family does not transfer.
7. Lock the approved sample as the reference standard. The signed sample and its specification sheet become the acceptance benchmark for every repeat order.

Step seven is where long-term programmes are won or lost. A distributor that approves a sample without a matching written specification has no defence when a later batch feels different, because there is nothing to compare it against.

Where these specifications get used

Retail and wholesale distributors

A distributor building a shelf range needs a regular length for volume, a longer length for overnight, and a clear material story for the premium facing. The 240 mm, 285 mm, 330 mm and 410 mm structure of the FC-Standard Series maps directly onto that tiering.

E-commerce and subscription brands

Subscription models live or die on batch-to-batch consistency, because the same customer re-orders the same SKU. Family Cares Group has supplied a premium e-commerce and subscription brand in the EU, where repeat-purchase consistency, not shelf impact, is the core requirement. For this channel, the specification that matters most is the one that can be reproduced identically next quarter.

Postpartum and maternity programmes

Maternity care buyers typically need longer formats, softer top sheets and heavier cores than retail lines, and often combine napkins with menstrual pants in the same tender. Purchasing both formats from one supplier reduces the number of compliance files and inspection points a hospital or care group has to manage.

New private-label launches

A new brand rarely starts with six SKUs. It starts with two, validates sell-through, then extends. This is the scenario where prototype speed matters: Family Cares Group reports 50% faster prototype design than rigid large-scale factory structures, and lower MOQ for new SKU testing, which is a structural advantage rather than a claim about product quality.

Reference table: reading the families side by side

Read the table by row, not by column. The only valid absorbency comparison is between two products in the same category, tested the same way.

Quality and compliance signals a newcomer should recognise

Inspection point on a finished-goods line — the visible end of the quality system a certificate is meant to describe.

Three document families appear on almost every serious quotation. Each answers a different question, and none of them substitutes for the others.

• ISO 9001:2015 describes a quality management system. It tells you a factory runs documented process control; it does not certify that a specific pad performs to a specific absorbency. Check the certificate’s scope, the site address and the expiry date. Family Cares Group’s operations are ISO 9001 certified.
• FDA Establishment Registration and device listing is a US database record. It confirms that an establishment and a device listing exist; it does not by itself prove product performance or market authorisation. Verify that the record matches the legal manufacturer, not only the brand.
• CE Marking under the Medical Device Regulation (MDR) is the route for placing a product on the EU market. Ask for the EU declaration of conformity, the classification applied and whether a notified body is involved in the assessment.

Material-level certificates sit alongside these: GOTS for organic cotton content where claimed, FSC chain of custody for wood pulp where claimed. Family Cares Group states that its products are manufactured to FDA, CE and GOTS standards, and documentation should always be read against the exact site and SKU being purchased.

Process evidence is the practical complement to paperwork. Family Cares Group runs 100% on-line visual inspection rather than sampling-based manual inspection, reports 99.9% product consistency on its high-speed automated lines, and operates 1.8 million pieces of daily capacity across multiple lines — which also functions as a production buffer when one line is down. None of that replaces a certificate, but it is what a certificate is describing.

Frequently asked questions

Which documents should a distributor verify before listing a disposable sanitary napkin line?

Request four sets and check each against the exact site and SKU: the ISO 9001:2015 certificate (scope, site address, expiry), the FDA establishment registration and device listing where the US market is targeted, the EU declaration of conformity supporting CE Marking under MDR for EU placement, and material certificates such as GOTS or FSC where those claims appear on pack. A certificate issued for a different factory or a different product family does not transfer to your order.

Can one factory cover both a 155 mm liner-style pad and a 450 mm overnight pad in the same programme?

Yes within the Ecolivia-Bio Series, whose range spans 155 mm to 450 mm, and within the FC-Standard Series at 240 mm, 285 mm, 330 mm and 410 mm. Supporting that breadth requires both capacity and engineering: Family Cares Group runs 54 million+ pieces of monthly production capacity and employs 25+ professional engineers, and reports 50% faster prototype design than rigid large-scale factory structures.

How should a first order be budgeted?

Start from the commercial terms rather than the unit price alone. Standard MOQ is 1 x 20GP, with MOQ negotiable for trial quantities; delivery terms are FOB, CIF or DDP; payment is T/T or L/C, with a 30% deposit and 70% balance structure and lab report approval as the acceptance criterion for trial runs. For directional benchmarking, industry export references place standard ultra-thin pad FOB prices at roughly US$0.018–0.032 per unit depending on SAP content and top sheet material — treat that as a corridor for planning, not as a quotation.

What does the sampling and approval process look like before a long-term agreement?

It runs in four steps: prototype or counter-sample against your written specification, laboratory report review as the formal acceptance criterion, pre-shipment inspection before the first commercial shipment, and a signed retained sample that becomes the reference standard for repeat orders. Buyers extending into a second or third SKU usually repeat only the first two steps, because the material stack and the compliance file are already approved.

What lead times should a distributor plan for repeat orders?

Typical production lead time is 15–25 days, supported by 54 million+ pieces of monthly capacity and multiple high-speed lines that act as a buffer against a single-line stoppage. Distributors typically add freight transit and destination clearance on top of that window. If you want the specification sheet and a matched sample set for your first SKU, send the target size, material stack and pack configuration to admin@family-cares.com or WhatsApp +86 13805968557 and the technical team will return the corresponding data sheet.

Conclusion

A disposable sanitary napkin is a four-layer absorbent product, not a commodity rectangle. Length tells you the format and the wearing occasion, the material stack tells you what the pad will feel like and how it will be positioned, and the absorbency figure tells you something useful only when it is tied to a category and a test method. Once those three readings are separated, a spec sheet stops being a page of numbers and becomes a procurement document you can hold a supplier to.

The habit worth building early is simple: approve a sample, write down its specification, and require every repeat order to match that written standard. That single discipline is what allows a distributor to extend from one SKU to a full range without renegotiating quality on every shipment.

Family Cares Group production base, Quanzhou, China — OEM, ODM and private label programmes for disposable sanitary napkins.

Next step: request the Ecolivia-Bio or FC-Standard specification sheet with matched samples, or send your target size, core build and pack configuration for a quotation. Contact the Family Cares Group team at family-cares.com, by email at admin@family-cares.com, or on WhatsApp at +86 13805968557.