A folding carton quotation usually comes back with three or four words that quietly decide everything downstream: SBS, FBB, kraft, or a recycled-content board. Buyers approve a sheet they have not seen printed, for a carton they have not yet held, and the choice looks like taste rather than engineering. Na prática, grade selection sits on four lines. It is how colour lands, how the box feels in the hand, how the crease behaves on the press, and what the pack can be called afterwards.
This article compares those four grades where a buyer has to choose. It covers stiffness and bulk, print and surface behaviour, cost direction, and how to decode the grade name on a quote. It is a selection guide, not a paper reference: it covers the trade-offs between grades and structures, and the short list of questions that turns an abbreviation into a decision.
Why Does the Paperboard Grade Change Everything Downstream?
Board grade is the line item cheapest to settle early and most expensive to reopen once artwork is locked and a plate made. Four consequences run through it.
- Print and graphics: surface whiteness, coating absorbency and smoothness control how a solid colour or pale tint reads. The same artwork on a different sheet is unlikely to match the proof you signed.
- Hand feel and shelf presence: stiffness and bulk decide whether a carton feels considered or collapses when a shopper picks it up.
- Die-cutting and folding: scoring, crease recovery and cracking are properties of the sheet. A grade that runs cleanly on one structure can dust, crack or spring open on another.
- Recovery and description: fibre make-up, coatings and any lamination determine what the finished pack can be called.
One caution. A frase nota do conselho means something else entirely in corrugated, where a supplier quotes a flute with a liner and medium combination. That is a separate system, covered in our guide to classes de papelão ondulado, and the two should not be mixed in one specification. This article stays with solid paperboard for folding cartons.
Grade is also the second question, not the first. If the format is still open, our guide to what folding cartons are covers structure, closure types, and where the format fits before the sheet choice enters.
Why Is SBS the White-Side Workhorse?
Solid bleached sulfate is the default answer whenever the graphics carry the sale. Bleached throughout and clay-coated on both faces, a printed SBS carton looks the same front and back. That matters more than buyers expect: open display cartons, boxes turned over in the hand, and cartons whose inside flap shows when the lid lifts.
Where SBS is normally the right starting point:
- Cosmetic and personal care cartons with heavy ink coverage, pale gradients or tight colour matching.
- Caixas de comida where the back panel carries legal and nutrition copy at the same visual quality as the front.
- Small electronics retail cartons with a clean reverse, or where the carton is the shelf-facing object rather than a shipper.
The trade-off is bulk. For the same weight, SBS reads thinner and bends more easily than a layered white board. A carton that must feel rigid for its size can push you toward a heavier sheet, a different grade, or a structural change such as a laminated lid. Because the sheet is hard and closely knit, a dark solid printed across a tight score should be tested on the exact grade rather than assumed to behave. Perguntar, too, which mill grade sits behind the word SBS. Two quotations can both say SBS yet differ in coating and fold behaviour, because the abbreviation names a family rather than one product.
When Do You Need FBB for Bulk and Stiffness?
Foldable bleached board is the reach when a carton must feel substantial without becoming heavy. Built in layers — bright coated faces over a lighter core — it gives more apparent thickness and bending resistance for the same weight on the scale. Resumidamente, SBS vs FBB is a trade between two-sided graphic fidelity and stiffness per unit of weight.
| What you are weighing up | SBS | FBB |
|---|---|---|
| Construction as it affects performance | Single-ply, bleached and coated through the sheet | Layered, bright coated faces over a lighter core |
| Stiffness per unit of weight | Lower; bends more readily | Higher; resists bending and holds a panel |
| Feel and apparent thickness | Thinner and denser in the hand | Thicker and more substantial in the hand |
| Front and reverse colour | Bright white on both faces | Bright front; reverse can read duller or greyer by grade |
| Two-sided printing | Safer when both faces carry artwork | Confirm on a sample of the exact grade |
| Crease and fold behaviour | Coated faces carry print; the dense surface can crack where dark ink crosses a tight score | Rígido; coating and ink at the crease need testing on the chosen grade |
| Cost behaviour | Price moves with weight, so rigidity costs material | Buys thickness without added weight, so it holds cost where feel matters |
| Usual first call | Graphic-led cosmetic, food and electronics cartons | Cartons that must feel rigid or resist crushing in a stack |
Two consequences follow. Request a sample of the exact FBB grade if the reverse is visible or printed, since the difference shows on the back. Also remember that bulk buys a feeling, not strength: a tall carton carrying weight over a long shelf span can still need structural help.
What Are the Look and Limits of Kraft and Recycled Board?
Kraft is chosen for appearance before performance. Its unbleached brown surface, visible fibre and soft grain read as practical and unfussy, suiting brands with restrained artwork whose customers expect a shipping-looking box rather than a shop-facing card. The same properties set the limits.
- Process colour on a brown ground: CMYK sinks and warms, and bright whites disappear for want of a white layer to print on. Design against the ground colour rather than fighting it.
- Tinta branca: treat it as a separate printing pass where the press supports it, and test legibility on the real sheet before committing small type.
- Lot-to-lot variation: kraft moves in shade between reels more than bleached board, so keep a colour-approved sample as the reference for later runs.
- Stiffness and tear: kraft is typically denser and lower in bulk, so it feels thinner at the same weight while resisting tearing — a fit for boxes handled roughly.
Recycled-content board is a different proposition. The speckled grey sheet, sometimes clay-coated white on one face, is usually specified for cost or recycled fibre, and both are legitimate reasons. The constraints arrive in order: a duller printed face, lower whiteness, more lot-to-lot variation, and grey flecks showing through light solids. Where the core stays grey, a design that exposes the inside of the carton needs that colour drawn in from the start.
We keep the environmental discussion short here on purpose. What a carton can be described as depends on fibre, revestimentos, laminations and the facilities available to whoever disposes of it. That is the subject of our guide to embalagem de papel reciclável.
How Do You Match a Grade to Product, Shelf, and Budget?
Three inputs settle most of this: how much the product weighs for the carton size, what the carton must do on the shelf, and how cost-sensitive the programme is. Write them down and the grade talk stops being about preference and becomes a shortlist.
| Product weight for the size | Display requirement | Budget posture | Grade to price first | What to confirm |
|---|---|---|---|---|
| Light, small carton | Printed front and back, tight colour match | Cost-sensitive | SBS | Coating on both faces; whether the panel stays flat |
| Light to medium, feel matters | Single-face graphics, rigidity on shelf | Middle of the range | FBB | Reverse colour, crease behaviour, priced basis |
| Medium, several items in one box | Premium presentation, lids, inserts or a window | Higher per unit | FBB or a laminated construction | Load path through the base, lid alignment, window fit |
| Any weight, ships in this carton | Practical look, one or two colours | Lowest | Kraft | Ground-colour effect on artwork, lot-to-lot shade |
| Light, high-volume secondary carton | Informational graphics | Lowest, recycled fibre wanted | Recycled-content board | Whether one white face is enough; how the core reads |
Read the rows as a starting point. Structure often outranks the sheet: a hinged lid, window cut-out or deeper wall can change the answer more than the grade name does. As a physical anchor, nosso custom folding gift box uses a coated paper face laminated to a heavier core board. That is our route when a box must hold its shape around several products rather than fold flat around one. For the wider range of grades and structures we produce, o folding cartons page is the reference.
How Do You Read the Grade on a Quote?
The grade name on a quotation is shorthand; the useful work is in the follow-up questions. If a quote reads something like “SBS, 350 gsm” — a figure used here for illustration only, not a recommendation — several deciding details are still missing from that line.
- Which face is coated: C1S and C2S mean coated one side or two, and decide whether the reverse can carry print or shows a greyer core.
- What the number is measured on: some programmes specify by weight per unit area, others by caliper, so two sheets can share a weight figure yet behave differently.
- Which mill grade sits behind the label: ask for the mill grade name or datasheet reference rather than accepting the generic abbreviation.
- Grain direction relative to the fold: a crease runs cleaner with the grain and is more exposed across it, which matters for dark solids and hanging holes.
- Surface treatment as a separate line: varnish, laminação de toque suave, foil and window film are decisions on top of the grade, not part of its name.
- Documentation for that exact grade: on food-contact or chain-of-custody projects, confirm which papers exist for the specific board before artwork begins.
Then put six things on the purchase order itself:
- The mill grade name or datasheet reference.
- The measurement basis, weight per unit area or caliper.
- Coated face count and grain requirement.
- Printing and finishing scope.
- The approved sample reference number.
- Any document the market or retailer requires.
That short block of specification prevents more disputes than any amount of email back-and-forth. Our article on how folding cartons are made covers the making; this one stays on the selection decision.
Perguntas frequentes
Is SBS better than FBB for cosmetic cartons?
Not automatically. SBS is the cleaner choice when both faces are visible and colour matching is strict; FBB suits cartons that must feel rigid for their size. Decide which matters more, then sample both.
Can kraft board be printed in full colour?
It can run a full-colour process, but the brown ground changes the result: colours read muted and warmer, and light areas lose detail. Proof against a kraft sheet, and plan white ink as its own pass if the press supports it.
Which paperboard grade is cheapest for folding cartons?
Directionally, recycled-content boards sit lowest, then kraft, then the bleached white boards, with laminated constructions higher. Where a project lands depends on grade availability, peso, finishing and volume, so treat this as a sequencing question for a quotation rather than a fixed price list.
Does a thicker carton mean a stronger carton?
Não necessariamente. Thickness gives rigidity and a substantial feel, but strength in a loaded carton also depends on structure, panel size, grain direction, closures and how the pack stacks. A thicker sheet in a weak layout can still fail, which is why the approved sample should carry the real product.
Why did my dark ink crack along the fold?
Usually a heavy ink film crossing a tight score on a dense coated sheet, sometimes worsened by grain direction, creasing pressure, or board condition. It is grade- and layout-specific, so test the ink area on the chosen grade, then rework the score or move the solid off the crease.
Can I print a recyclable claim on the carton?
That depends on the board, its coatings and laminations, and on whether recovery facilities where your customer lives can process it, so qualify a broad claim rather than assume it. Nos Estados Unidos, o FTC Green Guides set out how environmental claims are expected to be substantiated, and are worth reading before artwork goes to plate.
Considerações Finais
Choose the grade from the product outward, not from the sheet upward. SBS is the first call when graphics and a clean reverse carry the sale. FBB earns its place when stiffness matters more than two-sided print. Kraft is a design decision built around a brown ground, and recycled-content board answers cost and recycled fibre while accepting a duller printed face.
Then hold two habits. Put the measurement basis and mill grade name in writing, so two quotations can be compared, and approve a sample made from the intended production board.
If you are choosing a paperboard grade for a specific product, send the product weight, print requirements, and shelf context to PK Paper Box. That way the quote is built around your operation instead of a general rule.
