ISO 12636:2018

INTERNATIONAL ISO
STANDARD 12636
Second edition
2018-01
Graphic technology — Blankets for
offset printing
Technologie graphique — Blanchets pour impression offset
Reference number
©
ISO 2018
© ISO 2018
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ii © ISO 2018 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Requirements . 2
4.1 Information . 2
4.2 Dimension . 3
4.2.1 Thickness . 3
4.2.2 Mean thickness . 3
4.2.3 Accuracy of width and length . 3
4.2.4 Plan view . 4
4.3 Elongation . 4
4.4 Tensile strength . 4
4.5 Compressibility . 4
4.6 Thickness change . 4
4.6.1 Swelling and/or shrinkage due to printing ink component . 4
4.6.2 Swelling and/or shrinkage due to blanket washes . 4
4.7 Cut blanket markings . 4
5 Test methods . 4
5.1 General . 4
5.2 Thickness . 4
5.3 Elongation . 5
5.4 Tensile strength . 5
5.5 Load at specific deflection . 5
5.6 Compressibility – Deflection . 6
5.7 Compressibility – Indentation . 6
5.8 Surface texture . 8
5.9 Thickness change . 9
5.9.1 Swelling or shrinkage after exposure to a test liquid . 9
5.9.2 Swelling or shrinkage after recovery from exposure to a test liquid . 9
5.9.3 Exposure conditions for printing ink ingredients .10
5.9.4 Exposure conditions for washes .10
5.9.5 Report .10
Bibliography .11
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
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URL: www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 130, Graphic technology.
This second edition cancels and replaces the first edition (ISO 12636:1998), which has been technically
revised.
iv © ISO 2018 – All rights reserved

Introduction
The blanket is an essential part of every offset printing press. Its properties exert a profound influence
on the mechanical conditions within the press and the visual characteristics of the prints produced. It
is therefore useful to provide test methods, unified data, and tolerances for some essential properties
of the blankets. This permits the suppliers to state properties of blanket types in a standardized and
universally understood manner. It also helps the printer to select the appropriate blanket type for a
particular press type or press condition. A further benefit is that the design of printing presses can be
based on blanket data resulting from unified test methods.
INTERNATIONAL STANDARD ISO 12636:2018(E)
Graphic technology — Blankets for offset printing
1 Scope
This document defines vocabulary and specifies test methods, characteristics, ordering and labelling
information for blankets for offset printing. This document does not apply to un-tensioned or unclamped
blankets for offset printing, nor offset printing sleeves used on gapless presses.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at http://www.electropedia.org/
3.1
across cylinder direction
direction of the side of the blanket (3.4) as intended to be applied perpendicular to the direction of
rotation
3.2
around-the-cylinder direction
direction of the side of the blanket (3.4) as intended to be applied in the direction of the rotation
3.3
average thickness
mean of thickness measurements
3.4
blanket
composite body, consisting of coated carrier material, e.g. fabric, used for transfer of the printing ink
from the form onto the material to be printed on, e.g. for offset printing
3.5
load at specific deflection
average stress of a blanket (3.4) under compressive force
Note 1 to entry: It is expressed in kPa.
3.6
compressibility–deflection
average thickness reduction of a blanket (3.4) measured under a specific pressure
Note 1 to entry: It is expressed in millimetres.
3.7
compressibility–indentation
average depth of impression, I, in a blanket (3.4) measured under a specific pressure
Note 1 to entry: It is expressed in millimetres or as percentage indentation, I .
p
3.8
elongation
increase of the dimension in the around-the-cylinder direction (3.2) of a blanket (3.4) under
longitudinal stress
Note 1 to entry: It is expressed in percentage of the length at a specified force per width.
3.9
packing
underlay material placed under the blanket (3.4)
3.10
printing surface
side of the blanket (3.4) that is used for the transfer of printing ink
3.11
shrinkage
decrease in thickness due to mechanical forces and decrease in all dimensions due to exposure of the
blanket printing surface to a liquid
Note 1 to entry: It is expressed as a percentage of the original blanket thickness, or as an absolute thickness
decrease in millimetres.
3.12
sizes
dimensions (thickness, width and length) of a cut ready-to-use blanket (3.4)
3.13
swelling
increase in thickness due to exposure of the blanket printing surface to a liquid
Note 1 to entry: It is expressed as a percentage of the original blanket thickness or as an absolute thickness
increase in millimetres.
3.14
tensile strength
force per unit width required for breaking a blanket (3.4) under longitudinal stress in the around-the-
cylinder direction (3.2)
3.15
thickness variation
difference between the greatest and the smallest thickness value in millimetres
3.16
surface texture
average roughness of blanket surface, R
a
Note 1 to entry: It is expressed in micrometres.
4 Requirements
4.1 Information
The compatibility of the blankets to either conventional, dual use or ultraviolet (UV) inks shall be
documented.
2 © ISO 2018 – All rights reserved

The overall hardness and the microhardness are not specified in this document. They are the choice
of the manufacturer. If the manufacturer provides such information, the test method shall also be
documented and mentioned with the results.
The printing surface material formulation and surface texture are the choice of the manufacturer and
may be stated in technical descriptions by the supplier. The surface texture may vary, e.g. cas
...