HI STIFF
Stiffness that holds its shape.
HI STIFF is a high-stiffness kappa board engineered for book binding, hard covers, and luxury packaging applications where dimensional stability and rigidity are paramount.
Engineered for performance
HI STIFF is formulated to deliver superior bending stiffness — the critical property for book covers, case binding, and any application where the board must resist deformation under load or humidity.
Publishers, educational material manufacturers, and premium packaging converters rely on HI STIFF for its consistent stiffness values and excellent dimensional stability across varying humidity conditions.
The board is compatible with all standard case-binding adhesives and performs reliably on high-speed binding lines.
Key Features
- Superior bending stiffness for book covers and case binding
- Excellent dimensional stability in varying humidity
- Compatible with all standard case-binding adhesives
- Consistent caliper for reliable binding line performance
- Smooth surface for clean cloth and paper covering
- Available in custom sheet sizes and thicknesses
- ISO 9001 aligned quality management
- Manufactured from recycled fibre blends
Where HI STIFF performs best
Book Hard Covers
Case binding for textbooks, novels, and reference books.
Photo Albums
Hard cover boards for photo albums and memory books.
Luxury Rigid Boxes
Premium rigid boxes requiring high structural stiffness.
Stationery Covers
File covers, binders, and premium stationery products.
Technical Specifications
| Property | Value |
|---|---|
| Thickness Range (IS 1060 Cl. 5.1) | 1.0 mm – 4.0 mm |
| Base Grammage (IS 1060 / ISO 536) | 750 gsm/mm (stiff grade basis) |
| Caliper Tolerance (IS 1060 Cl. 5.1 / ISO 534) | ± 0.05 mm |
| Taber Stiffness — MD (ISO 2493) | ≥ 12 mN·m (1.0 mm); ≥ 30 mN·m (2.0 mm) |
| Taber Stiffness — CD (ISO 2493) | ≥ 8 mN·m (1.0 mm); ≥ 20 mN·m (2.0 mm) |
| Burst Factor (IS 1060 Cl. 5.3 / ISO 2758) | ≥ 14 kPa·m²/g |
| Moisture Content (IS 1060 Cl. 5.5) | 6% – 9% |
| Surface | Natural grey, uncoated — smooth for cloth/paper covering |
| Ash Content (IS 1060 Cl. 5.6) | ≤ 20% |
| Sheet Size | Custom cut to order |
| Packing | Shrink-wrapped pallets |
| MOQ | 1 MT |
All specifications are indicative. Contact our technical team for application-specific requirements.
HI STIFF — In Depth
Which board thickness do you need?
Select your box type and size — get an instant recommendation for the right Kappa Board grade, thickness, and GSM.
Step 1 — What are you making?
Step 2 — What size is the box?
Where HI STIFF performs best
Book Hard Covers
Case binding for textbooks, novels, and reference books.
Photo Albums
Hard cover boards for photo albums and memory books.
Luxury Rigid Boxes
Premium rigid boxes requiring high structural stiffness.
Stationery Covers
File covers, binders, and premium stationery products.
Sowji HI STIFF vs Generic Grey Board
How Sowji Papers' certified Kappa Board compares to unbranded commodity grey board from generic mills.
* Generic board data based on industry averages from unbranded commodity mills. Actual values vary by supplier.
Request Test ReportsEverything about HI STIFF
Interested in HI STIFF?
Request a sample pack or speak to our technical team about your specific requirements.
