What Is Stone Paper? Composition, Structure, and How It Fundamentally Differs from Wood-Pulp Paper

What Is Stone Paper? Composition, Structure, and How It Fundamentally Differs from Wood-Pulp Paper

Direct answer: Stone paper in the Flexstone® range is a printable sheet or film with no wood-pulp fibre. Calcium carbonate is 60–80% by weight and thermoplastic resin is 20–40%. It is fully waterproof and tear-resistant, and it does not shrink or swell with humidity. It is a candidate for fibre-free print, labels, wallcovering substrates and pellets. Outdoor durability is below PVC, and it is the wrong material for fire-rated assemblies, clear film, high-temperature retort, or any job that needs a biodegradable or compostable claim. Print, optical, temperature, working-environment and storage figures are not family-wide: they apply only to the named grade group and spec sheet.

In Stone Paper, 60–80% Calcium Carbonate Is Bound by 20–40% Resin, and There Is No Wood-Pulp Fibre

Flexstone® stone paper from Guangzhou Newlife New Material Co., Ltd. (Newlife) is 60–80% calcium carbonate bound by 20–40% thermoplastic resin, with no wood-pulp fibre in the published composition. The same ratio is 600–800 kg of calcium carbonate and 200–400 kg of resin per tonne; that is the published percentage applied to one tonne, not a second specification. Catalogue density series are FS at 1.0 g/cm³, FM at 1.2 g/cm³ and FG at 1.4 g/cm³, with single-layer thickness from 0.08 mm to 0.4 mm. Sheets can be die-cut to size where that supply form is offered. Production consumes no trees and uses no process water — only circulating cooling water. That is Newlife published product data, not a third-party life-cycle assessment.

Wood-pulp paper is a different construction: a web of cellulose fibres. Those fibres take up water, so a fibre sheet can swell, lose strength and break down when wet, and it tears along the fibre network. That sentence is general paper behaviour, not a Newlife test of a named paper grade. Stone paper contains no fibres: it is fully waterproof and tear-resistant, and in humid conditions it is dimensionally stable — it does not shrink or swell with humidity. At equal thickness it is heavier than most paper. Because it contains thermoplastic resin, its heat limit is lower than paper; published temperature numbers exist only for named grade groups, not as a Flexstone-wide heat limit. It does not absorb the ink vehicle; ink anchorage relies on the surface coating. In the Flexstone label brochure, coated paper and Flexstone are both rated excellent for printability. Coating, adhesive, density series and the spec sheet still decide the job. The construction summary is the stone paper fundamentals page.

Wood-Pulp Paper and Stone Paper Diverge at the Structure Level, and Grade Limits Still Apply Downstream

Process behaviour follows from the published construction and from grade-group data. It does not follow from the name “stone paper” alone.

Side-by-side comparisons of the published baselines sit on the compare page. Do not describe one density series as the high-opacity series. Opacity is published by grade group, not by FS, FM or FG: FS-2K20–30 and the FS wall-fabric composite grades are ≥95%; FM wall-fabric composite grades are ≥92%; FG-2K15 is ≥85%; other spec-sheet grades are ≥90%. Whiteness is ≥82 on spec-sheet grades that publish optical data. A general colour description is only “warm white and opaque.”

The Three Density Series — FS at 1.0, FM at 1.2 and FG at 1.4 g/cm³ — Are a Stiffness Choice, Not an Opacity Ranking

FS at 1.0 g/cm³ is the soft, light, paper-like series; FM at 1.2 g/cm³ is the balanced middle; FG at 1.4 g/cm³ is the rigid series. The choice is hand-feel, stiffness and weight, not a quality ranking. The same coating code can appear on more than one density series, but not every code exists on every density. Read the grade, not the density letter alone.

Moving up a density series at the same thickness increases nominal mass per square metre. It does not raise a published opacity band, and it does not create a heat rating. Opacity bands are the grade-group figures above. Heat figures, where they exist, are in the spec-sheet section below.

Nominal Basis Weight of Non-Adhesive Grades Follows Thickness × Density × 1000

For non-adhesive grades, nominal basis weight (g/m²) ≈ thickness (mm) × density (g/cm³) × 1000. Newlife publishes this as a nominal identity, not as a measured basis weight for every SKU. Listed models publish their own basis weight, and those figures stand as published: FS-S22, shelf life 12 months, 220±22 g/m²; FS-S32, shelf life 12 months, 320±32 g/m²; wall-fabric composites FM-S27-FAB5 420±42, FS-K20-FAB5 300±30, FS-K25-FAB5 350±35, FM-K20-FAB5 340±34, FM-K25-FAB5 400±40, FM-S22-FAB5 360±36. Do not replace those figures with the nominal identity. Not every thickness is offered in every density series. The 12-month shelf life in that list is the published figure for FS-S22 and FS-S32 only. It is not a Flexstone-wide shelf life, and it is not stated here for the wall-fabric composites.

These areas are arithmetic from the nominal identity, not published yield specs. Freight and yield should use the nominal basis weight of the grade ordered. Moving from a 0.15 mm FS sheet (150 g/m²) to a 0.20 mm FG sheet (280 g/m²) changes mass per square metre by 280 ÷ 150, not by the thickness ratio 0.20 ÷ 0.15.

The identity does not apply to adhesive constructions. Total thickness is not face thickness, and it differs by grade. For a 0.15 mm face, wide-format K-PSA (NMEQS-MACO 294) publishes a total thickness of 0.25 mm, and narrow-web label stock (NMEQS-MACO 295) publishes a total thickness of 0.23 mm. Do not quote 0.25 mm for the narrow-web grade, do not quote 0.23 mm for wide-format K-PSA, and do not treat 0.15 mm as the total. Other face thicknesses are not given those two totals.

Specifying a Humidity-Exposed Label Starts from the Narrow-Web Grade Group, Not from “Stone Paper”

This is a decision sequence using published grade rules, not a reported installation and not a customer result. A fibre label that changes size as indoor humidity rises is a reason to look at a fibre-free face. Stone paper contains no fibres: it is fully waterproof and tear-resistant, and it does not shrink or swell with humidity. It is not a reason to skip the spec sheet.

Stop at the published use window before choosing a coating. For spec-sheet grades, the use environment — the finished item in service, not a process ceiling — is −20 °C to 60 °C and 20–80% RH, with temperature change under 15 °C within 30 minutes. Condensing steam, standing water, or a hotter surface is outside that window. High-temperature retort is outside it as well; those jobs stay with PET. Brochure-only grades do not publish this use window.

If the window fits, the matching family for a label press is narrow-web label stock on the label-stock series page, spec sheet NMEQS-MACO 295. On that sheet the K coating is offset, flexo and UV-curing ink on label presses. It is not a wide-format inkjet medium. If the face is 0.15 mm, order the total thickness published for that grade on NMEQS-MACO 295, which is 0.23 mm, not “0.15 mm total,” and not the 0.25 mm total of wide-format K-PSA on NMEQS-MACO 294.

Adhesive follows the published description, then a test on the real surface:

- PSA is a medium-tack permanent adhesive. - WRA is a water-based removable adhesive. - DPA is the dot-pattern air-release construction, published for clean removal within six months on smooth indoor surfaces.

Published shear for these adhesives is 0.5 kg hung on a 25 × 25 mm area for 24 hours without slip. That shear note is not a fire rating and not a wet-service approval. DPA’s six-month removal note is for smooth indoor surfaces, not for a condensing wall.

Match the press to the grade group, and do not borrow numbers from another sheet:

- HP Indigo uses I / 2I grades. Unqualified, “2I” means HP Indigo only. - Dry toner uses the FG digital-press grades FG-2I, FG-I15-PSA and FG-I20-PSA (NMEQS-MACO 298), which also list UV-curing, offset and screen. - 2K grades on NMEQS-MACO 293 are not compatible with HP Indigo. Dry toner on that sheet needs a test first. - NMEQS-MACO 295 has no published temperature figure in this source set. Do not copy 80 °C, 100 °C or 120 °C from NMEQS-MACO 293 or 298.

Engineering suggestion, not a published parameter: run a press trial on the shop’s own ink set and check ink adhesion, edge curl and dimensional change after humidity cycling inside the use window. Lamination, foil stamping, heat transfer, sewing and a named ink brand are not published processes; the same trial list applies, and no set-up values are implied.

Specifications and Process Windows Are Published per Grade Group and Spec Sheet, Not for Stone Paper as a Whole

Optical, temperature, storage and supply figures belong to a grade group and a spec sheet. They are not Flexstone-wide limits. Spec sheets NMEQS-MACO 293, 294, 295, 296, 298, 299 and 303 are on the downloads page. Grades that appear only in the brochure publish nominal basis weight, and none of the windows below.

“UV” is two processes. Wide-format UV inkjet is not the same thing as UV-curing ink on a press. Do not write that S, K and 2K are all “UV grades.”

Do not write “Flexstone is rated to 120 °C,” and do not give the FG short-term figure to an FS grade. Grades without a published figure should be tested before any heated process, and they are not for retort or other extreme-heat work.

A combined working-environment band, or a combined storage band, is not a fact about any one Flexstone grade. Those lines are printed on the individual spec sheet and are not restated here as one interval. Read them on the sheet of the grade being ordered. Brochure-only grades do not publish working, storage or shelf-life conditions. The 12-month shelf life named for FS-S22 and FS-S32 is not copied onto any other grade in this article.

Published supply forms, confirmed on the grade’s own sheet, are: wide-format inkjet rolls of 50 m at 1270 / 1370 / 1524 mm, except wide-format FS-K15-PSA-80G and FS-K20-PSA-80G, which are 1270 / 1370 mm; wall-fabric composite rolls of 50 m × 1500 mm; narrow label stock slit to 210 / 310 / 410 / 510 mm; and FG digital-press sheets at 460 × 320 mm and 480 × 330 mm. The product one-pager lists a material web width of 1600 mm; that figure is not a substitute for the catalogue roll widths. Brochure-only grades do not publish this supply list.

Outdoor Durability Is Below PVC, and Stone Paper Is the Wrong Choice for Fire-Rated Assemblies, Transparency and Very-High-Temperature Work

Outdoor durability is below PVC. No weathering or outdoor-UV durability claim is published.

Applications that require a strict fire rating still need flame-retardant PVC. Flexstone is not specified for that requirement.

Catalogue grades are warm white and opaque. They cannot replace a clear film. At equal thickness it is heavier than most paper.

The composition contains thermoplastic resin, so its heat limit is lower than paper. It is not for high-temperature retort or other extreme-heat processes; PET remains the appropriate choice there. No food-contact or medical claim is published.

No biodegradable or compostable claim is made. Published end-of-life routes are only the two in the product data: regrind and remanufacture, and energy recovery.

The Composition and Grade Data in This Article Come from Newlife Spec Sheets, the Brochure and the Pellet Brief

Composition, density series, opacity bands, temperature figures and the use-environment window above are Newlife published product data from spec sheets NMEQS-MACO 293, 294, 295, 296, 298, 299 and 303, the Flexstone brochure and product one-pagers, and the Flexstone Pellet product brief. Working-environment and storage temperature and relative humidity are not given here, because they are not one published interval. They are not a customer case study. Check the grade sheet before treating a figure as ordered material.

The same manufacturer supplies Flexstone pellets (PP / PE series). The pellet brief, not the sheet spec sheets, states inorganic content above 60%, density about 1.5 g/cm³, and processing on existing injection, blow-moulding, extrusion and thermoforming equipment. Pellets can be mechanically recycled as a single material, and offcuts can be regranulated. Shrinkage, a moulding-temperature window and mechanical curves are not published here and are not derived from the sheet grades. Sheet composition at 60–80% calcium carbonate is not the pellet figure.

Sustainability figures below are Newlife published product data, not a third-party LCA. They stay with their own baselines and are not one combined percentage.

Those baselines are stated on the sustainability page. The production note — no trees, no process water, only circulating cooling water — is a separate published statement. It is not a restatement of the 20–35 tonne water range.

Frequently Asked Questions About Stone Paper Composition and Structure

Is stone paper simply plastic filled with chalk? It is a mineral-filled sheet: 60–80% calcium carbonate bound by 20–40% thermoplastic resin, with no wood-pulp fibre. Neither “paper” nor “plastic film” is a complete description. Handling and print route still depend on the grade group.

Does stone paper absorb water the way paper does? It contains no fibres. It is fully waterproof and tear-resistant, and it does not shrink or swell with humidity. That is not a numerical water-absorption rating. Adhesion, ink anchorage and the use window of −20 °C to 60 °C and 20–80% RH, for spec-sheet grades, still have to be checked on the job.

Why is it heavier at the same thickness? Published density is 1.0, 1.2 or 1.4 g/cm³ by series. For a non-adhesive grade, nominal basis weight (g/m²) ≈ thickness (mm) × density (g/cm³) × 1000. At equal thickness it is heavier than most paper. Adhesive total thickness is a separate, grade-specific figure: 0.25 mm for a 0.15 mm face on wide-format K-PSA (NMEQS-MACO 294), and 0.23 mm for a 0.15 mm face on narrow-web label stock (NMEQS-MACO 295).

Can I run it on my existing press? Only if the coating and spec sheet match the press. Wide-format UV inkjet and on-press UV-curing ink are different notes. NMEQS-MACO 293 2K grades are not compatible with HP Indigo, and dry toner on that sheet needs a test. HP Indigo uses I / 2I grades. Dry toner equipment should use the FG digital-press grades FG-2I, FG-I15-PSA and FG-I20-PSA. Processes and ink brands that are not listed need a small trial.

Is it biodegradable? No biodegradable or compostable claim is made. Published end-of-life routes are regrind and remanufacture, and energy recovery.

Next Step:

Send Your Press, Thickness and Use-Environment Data to Get a Sample and a Spec Sheet

A useful match needs the job data, not a family name. Include printing equipment and ink type; web width or sheet size; thickness and density series (FS, FM or FG); whether an adhesive is needed and what surface it will meet; and the use environment and duration, including whether the job is short-term indoor, short-term outdoor, or outside the published window.

Contact the Flexstone application engineering team for samples and the matching spec sheet: https://www.stonepapers.net/en/contact. Confirm the grade group against that sheet, and run a small press trial before a production commitment.

References

1. Newlife spec sheets NMEQS-MACO 293, 294, 295, 296, 298, 299 and 303 — coatings, optical values, temperature, use environment and supply formats. Adhesive total thickness for a 0.15 mm face is 0.25 mm on NMEQS-MACO 294 and 0.23 mm on NMEQS-MACO 295. https://www.stonepapers.net/en/downloads 2. Newlife knowledge base, stone paper fundamentals — composition and the contrast with a wood-pulp fibre web. https://www.stonepapers.net/en/knowledge-base/stone-paper-fundamentals 3. Flexstone brochure and product one-pagers — brochure-only grades (including FM-2K, 0.35 mm 2K, FS-2I and FM-2I) publish nominal basis weight only; catalogue roll widths and the 1600 mm one-pager web width are separate figures. Product range: https://www.stonepapers.net/en/products 4. Flexstone Pellet product brief — inorganic content, density, existing equipment and mechanical recycling of pellets. https://www.stonepapers.net/en/products/pellet 5. Newlife published sustainability product data, with baselines kept separate (coated paper; BOPP pearl synthetic paper). Not a third-party LCA. https://www.stonepapers.net/en/sustainability