Overview
ISO 12636:2018 - Graphic technology - Blankets for offset printing defines vocabulary, test methods, characteristic requirements, and ordering/labelling information for ready-to-use blankets used in offset printing. The standard standardizes measurement and reporting so suppliers, printers and press designers can compare blanket properties reliably. It does not apply to un‑tensioned or unclamped blankets or to offset printing sleeves used on gapless presses.
Key topics and technical requirements
- Vocabulary and definitions for terms such as across‑cylinder, around‑the‑cylinder, compressibility (deflection and indentation), elongation, tensile strength, swelling and shrinkage.
- Test environment: measurements are specified to be made at (23 ± 2) °C and (50 ± 5) % RH.
- Thickness and dimensions
- Test method for thickness and mean thickness (measurement points specified).
- Nominal thickness guidance: for applications with packing, typical nominal thicknesses are 1.68 mm or 1.95 mm.
- Thickness variation tolerances: ±0.02 mm for blankets with area ≤ 1.5 m2; ±0.03 mm for larger blankets; no single reading may deviate more than 0.05 mm from ordered thickness.
- Width/length tolerances: ±3 mm if a side ≤ 1 m, otherwise ±4 mm. Planarity: sides must be right angles; diagonal/side differences ≤ 0.5 %.
- Mechanical properties
- Elongation in the around‑the‑cylinder direction: < 1.5 % (test method provided).
- Tensile strength: for blankets ≥ 1.68 mm, > 40 N/mm (test method provided).
- Compressibility: methods for deflection and indentation are specified; load at specific deflection may be used.
- Chemical compatibility
- Thickness change limits after exposure to ink ingredients: maximum +4 % swelling or −2 % shrinkage (test method specified).
- Blanket washes compatibility should be tested per the standard.
- Ordering and labelling
- Required reporting on cut blankets: average actual thickness, width, length (identify around‑the‑cylinder direction), batch control number, manufacturer and blanket trade name.
- Hardness and surface texture are manufacturer options; if supplied, the test method must be documented.
Applications and users
ISO 12636:2018 is used by:
- Blanket manufacturers to publish standardized product data.
- Commercial and packaging printers to select blankets compatible with press conditions and inks (conventional, dual‑use, UV).
- Press designers and OEMs to base mechanical design on unified blanket data.
- Quality control and testing laboratories for routine acceptance and compatibility testing.
- Procurement teams specifying dimensions, tolerances and compatibility requirements.
Keywords: ISO 12636:2018, blankets for offset printing, graphic technology, compressibility, thickness, tensile strength, swelling, shrinkage, test methods.
Related standards / committees
Prepared by ISO/TC 130 (Graphic technology). The document contains no normative references; users should consult other ISO graphic technology standards where applicable for broader press and ink specifications.
