SIST EN ISO 306:2023
(Main)Plastics - Thermoplastic materials - Determination of Vicat softening temperature (VST) (ISO 306:2022)
Plastics - Thermoplastic materials - Determination of Vicat softening temperature (VST) (ISO 306:2022)
This document specifies four methods for the determination of the Vicat softening temperature (VST) of thermoplastic materials:
— Method A50 using a force of 10 N and a heating rate of 50 °C/h;
— Method B50 using a force of 50 N and a heating rate of 50 °C/h;
— Method A120 using a force of 10 N and a heating rate of 120 °C/h;
— Method B120 using a force of 50 N and a heating rate of 120 °C/h.
The methods specified are applicable only to thermoplastics, for which they give a measure of the temperature at which the thermoplastics start to soften rapidly.
Kunststoffe - Thermoplaste - Bestimmung der Vicat-Erweichungstemperatur (VST) (ISO 306:2022)
1.1 Diese Internationale Norm legt vier Verfahren zur Bestimmung der Vicat-Erweichungstemperatur (VST) von Thermoplasten fest:
- Verfahren A50 mit einer Kraft von 10 N und einer Heizrate von 50 °C/h;
- Verfahren B50 mit einer Kraft von 50 N und einer Heizrate von 50 °C/h;
- Verfahren A120 mit einer Kraft von 10 N und einer Heizrate von 120 °C/h;
- Verfahren B120 mit einer Kraft von 50 N und einer Heizrate von 120 °C/h.
1.2 Die festgelegten Verfahren sind nur auf Thermoplaste anwendbar, für die sie eine Kennzahl der Temperatur liefern, bei der die Thermoplaste beginnen schnell zu erweichen.
Plastiques - Matières thermoplastiques - Détermination de la température de ramollissement Vicat (VST) (ISO 306:2022)
Le présent document spécifie quatre méthodes de détermination de la température de ramollissement Vicat (VST) des matières thermoplastiques:
— méthode A50 utilisant une force de 10 N et une vitesse d’élévation de la température de 50 °C/h;
— méthode B50 utilisant une force de 50 N et une vitesse d’élévation de la température de 50 °C/h;
— méthode A120 utilisant une force de 10 N et une vitesse d’élévation de la température de 120 °C/h;
— méthode B120 utilisant une force de 50 N et une vitesse d’élévation de la température de 120 °C/h.
Les méthodes spécifiées sont uniquement applicables aux thermoplastiques. Elles permettent de mesurer la température à laquelle le ramollissement de ces matières devient rapide.
Polimerni materiali - Plastomeri - Ugotavljanje temperature zmehčišča po Vicatu (VST) (ISO 306:2022)
Ta dokument določa štiri metode za ugotavljanje temperature zmehčišča plastomerov po Vicatu (VST):
– metoda A50 z uporabo sile 10 N in hitrosti segrevanja 50 °C/h;
– metoda B50 z uporabo sile 50 N in hitrosti segrevanja 50 °C/h;
– metoda A120 z uporabo sile 10 N in hitrosti segrevanja 120 °C/h;
– metoda B120 z uporabo sile 50 N in hitrosti segrevanja 120 °C/h.
Opisane metode se uporabljajo za polimerne materiale, za katere podajajo temperaturno meritev, pri kateri se plastomeri začnejo hitro mehčati.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 306:2023
01-februar-2023
Nadomešča:
SIST EN ISO 306:2014
Polimerni materiali - Plastomeri - Ugotavljanje temperature zmehčišča po Vicatu
(VST) (ISO 306:2022)
Plastics - Thermoplastic materials - Determination of Vicat softening temperature (VST)
(ISO 306:2022)
Kunststoffe - Thermoplaste - Bestimmung der Vicat-Erweichungstemperatur (VST) (ISO
306:2022)
Plastiques - Matières thermoplastiques - Détermination de la température de
ramollissement Vicat (VST) (ISO 306:2022)
Ta slovenski standard je istoveten z: EN ISO 306:2022
ICS:
83.080.20 Plastomeri Thermoplastic materials
SIST EN ISO 306:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 306:2023
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SIST EN ISO 306:2023
EN ISO 306
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2022
EUROPÄISCHE NORM
ICS 83.080.20 Supersedes EN ISO 306:2013
English Version
Plastics - Thermoplastic materials - Determination of Vicat
softening temperature (VST) (ISO 306:2022)
Plastiques - Matières thermoplastiques - Kunststoffe - Thermoplaste - Bestimmung der Vicat-
Détermination de la température de ramollissement Erweichungstemperatur (VST) (ISO 306:2022)
Vicat (VST) (ISO 306:2022)
This European Standard was approved by CEN on 20 October 2022.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 306:2022 E
worldwide for CEN national Members.
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SIST EN ISO 306:2023
EN ISO 306:2022 (E)
Contents Page
European foreword . 3
2
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SIST EN ISO 306:2023
EN ISO 306:2022 (E)
European foreword
This document (EN ISO 306:2022) has been prepared by Technical Committee ISO/TC 61 "Plastics" in
collaboration with Technical Committee CEN/TC 249 “Plastics” the secretariat of which is held by NBN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by May 2023, and conflicting national standards shall be
withdrawn at the latest by May 2023.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 306:2013.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 306:2022 has been approved by CEN as EN ISO 306:2022 without any modification.
3
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SIST EN ISO 306:2023
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SIST EN ISO 306:2023
INTERNATIONAL ISO
STANDARD 306
Sixth edition
2022-11
Plastics — Thermoplastic materials
— Determination of Vicat softening
temperature (VST)
Plastiques — Matières thermoplastiques — Détermination de la
température de ramollissement Vicat (VST)
Reference number
ISO 306:2022(E)
© ISO 2022
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SIST EN ISO 306:2023
ISO 306:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
© ISO 2022 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 306:2023
ISO 306:2022(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Principle . 2
5 Apparatus . 2
5.1 Means of producing penetration . 2
5.2 Indenter . . . 3
5.3 Heating equipment . 3
5.4 Weights . 3
5.5 Temperature-measuring device . 3
5.6 Penetration-measuring device . 5
5.7 Micrometers and gauges . 6
6 Test specimens . 6
7 Conditioning . 6
8 Procedure .7
9 Precision . 7
10 Test report . 7
Annex A (informative) Comparison of VST results obtained with liquid-filled heating bath
and direct-contact heating unit . 9
Annex B (informative) Comparison of VST results obtained with liquid-filled heating bath
and fluidized bed .11
Annex C (informative) Repeatability and precision .13
Bibliography .16
iii
© ISO 2022 – All rights reserved
---------------------- Page: 9 ----------------------
SIST EN ISO 306:2023
ISO 306:2022(E)
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
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
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).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee TC 61, Plastics, Subcommittee SC 2, Mechanical
behavior, in collaboration with the European Committee for Standardization (CEN) Technical Committee
CEN/TC 249, Plastics, in accordance with the Agreement on technical cooperation between ISO and CEN
(Vienna Agreement).
This sixth edition cancels and replaces the fifth edition (ISO 306:2013), which has been technically
revised.
The main changes are as follows.
— The document has been updated to allow for the use of commercial universal equipment (i.e.
covering both ISO 75 and ISO 306) and modern testing practices.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
© ISO 2022 – All rights reserved
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SIST EN ISO 306:2023
INTERNATIONAL STANDARD ISO 306:2022(E)
Plastics — Thermoplastic materials — Determination of
Vicat softening temperature (VST)
1 Scope
1.1 This document specifies four methods for the determination of the Vicat softening temperature
(VST) of thermoplastic materials:
— Method A50 using a force of 10 N and a heating rate of 50 °C/h;
— Method B50 using a force of 50 N and a heating rate of 50 °C/h;
— Method A120 using a force of 10 N and a heating rate of 120 °C/h;
— Method B120 using a force of 50 N and a heating rate of 120 °C/h.
1.2 The methods specified are applicable only to thermoplastics, for which they give a measure of the
temperature at which the thermoplastics start to soften rapidly.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 291, Plastics — Standard atmospheres for conditioning and testing
ISO 293, Plastics — Compression moulding of test specimens of thermoplastic materials
ISO 294-1, Plastics — Injection moulding of test specimens of thermoplastic materials — Part 1: General
principles, and moulding of multipurpose and bar test specimens
ISO 294-2, Plastics — Injection moulding of test specimens of thermoplastic materials — Part 2: Small
tensile bars
ISO 294-3, Plastics — Injection moulding of test specimens of thermoplastic materials — Part 3: Small
plates
ISO 472, Plastics — Vocabulary
ISO 2818, Plastics — Preparation of test specimens by machining
ISO 16012, Plastics — Determination of linear dimensions of test specimens
ISO 20753, Plastics — Test specimens
IEC 60584-1, Thermocouples — Part 1: EMF specifications and tolerances
IEC 60584-3, Thermocouples — Part 3: Extension and compensating cables — Tolerances and identification
system
IEC 60751, Industrial platinum resistance thermometers and platinum temperature sensors
1
© ISO 2022 – All rights reserved
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SIST EN ISO 306:2023
ISO 306:2022(E)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 472 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
penetration
distance over which the indenting tip has to penetrate into the specimen under test
Note 1 to entry: It is expressed in millimetres (mm).
3.2
load
force applied to test specimen by means of the indenting tip
Note 1 to entry: It is expressed in Newtons (N).
3.3
Vicat softening temperature
VST
temperature at which a flat-ended indenter will penetrate the specimen to a depth of 1 mm under a
specified load (3.2) using a selected uniform rate of temperature rise
Note 1 to entry: It is expressed in degrees Celsius (°C).
4 Principle
The temperature at which a standard indenting tip with a flat point, under a standardized load,
penetrates 1 mm into the surface of a plastic test specimen is determined. The indenting tip exerts
a specified force perpendicular to the test specimen, while the specimen is heated at a specified and
uniform rate.
The temperature, in degree Celsius (°C), of the specimen, measured as close as possible to the indented
area at 1 mm penetration, is quoted as the VST.
5 Apparatus
5.1 Means of producing penetration
The apparatus shall be constructed essentially as shown in Figure 1 (or Figure 2). It consists of a rigid
metal frame in which a rod moves freely in the vertical direction. One end of the rod is fitted with a
weight-carrying plate and the other end is equipped with an indenting tip. The base of the frame is
fitted with a support plate or other suitable load-application device.
It is recommended that the rod and frame(s) be constructed of low thermal expansion material. Unless
vertical parts of the apparatus have the same coefficient of linear thermal expansion, the difference
in change of length of these parts during the test introduces an error in the reading of the apparent
penetration of the test specimen.
At the time of manufacture, or after repair or replacement of test frame, a blank test shall be made on
each apparatus using a test specimen made of rigid material having a low coefficient of expansion and
a thickness comparable to that of the specimen under test. The blank test shall cover the temperature
ranges to be used in the actual determination, and a correction term shall be determined for each
temperature. If the correction term is 0,02 mm or greater, its value and algebraic sign shall be recorded;
2
© ISO 2022 – All rights reserved
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SIST EN ISO 306:2023
ISO 306:2022(E)
and the term applied to each test result by adding it algebraically to the reading of the apparent
penetration of the test specimen.
NOTE Invar and borosilicate glass have been found suitable as materials for the test specimen in the blank
test.
5.2 Indenter
It shall be made of hardened steel, at least 2 mm long, of circular cross-section and of area
2
(1,000 ± 0,015) mm (corresponding to an indenting tip diameter of (1,128 ± 0,008) mm) and fixed at
the bottom of the rod. The indenter, when in contact with the specimen, shall be perpendicular to the
rod. The tip shall be free from burrs or other imperfections.
5.3 Heating equipment
The heating equipment shall be a heating bath containing a suitable liquid, a fluidized bed, or a direct
contact heating unit, see Figure 2. For heat transfer media other than gas (air) the test specimen shall
be immersed to a depth of at least 35 mm.
An efficient stirrer or means to fluidize the solid heat transfer medium shall be provided. If liquids are
used for heat transfer, it shall be established that the liquid chosen is stable over the temperature range
used and does not affect the material under test, for example causing it to swell or crack.
The method using a liquid heat transfer medium shall be considered a reference method in case of
doubts or conflicts, if possible, in the temperature range under consideration.
The heating equipment shall be provided with a control unit so that the temperature is raised at a
uniform rate of (50 ± 5) °C/h or (120 ± 10) °C/h.
The heating rate shall be verified periodically either by checking the automatic temperature reading, or
manually checking the temperature. The requirement for the heating rate shall be considered satisfied
if, over every 6 min interval during the test, the temperature change is (5,0 ± 0,5) °C or (12,0 ± 1,0) °C.
It is allowable for the first 10 min or up to 40 °C of the ram
...
SLOVENSKI STANDARD
oSIST prEN ISO 306:2022
01-januar-2022
Polimerni materiali - Plastomeri - Ugotavljanje temperature zmehčišča po Vicatu
(VST) (ISO/DIS 306:2021)
Plastics - Thermoplastic materials - Determination of Vicat softening temperature (VST)
(ISO/DIS 306:2021)
Kunststoffe - Thermoplaste - Bestimmung der Vicat-Erweichungstemperatur (VST)
(ISO/DIS 306:2021)
Plastiques - Matières thermoplastiques - Détermination de la température de
ramollissement Vicat (VST) (ISO/DIS 306:2021)
Ta slovenski standard je istoveten z: prEN ISO 306
ICS:
83.080.20 Plastomeri Thermoplastic materials
oSIST prEN ISO 306:2022 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
oSIST prEN ISO 306:2022
---------------------- Page: 2 ----------------------
oSIST prEN ISO 306:2022
DRAFT INTERNATIONAL STANDARD
ISO/DIS 306
ISO/TC 61/SC 2 Secretariat: SAC
Voting begins on: Voting terminates on:
2021-11-18 2022-02-10
Plastics — Thermoplastic materials — Determination of
Vicat softening temperature (VST)
Plastiques — Matières thermoplastiques — Détermination de la température de ramollissement Vicat
(VST)
ICS: 83.080.20
This document is circulated as received from the committee secretariat.
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
ISO/CEN PARALLEL PROCESSING
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 306:2021(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. © ISO 2021
---------------------- Page: 3 ----------------------
oSIST prEN ISO 306:2022
ISO/DIS 306:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
© ISO 2021 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 306:2022
ISO/DIS 306:2021(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 2
6 Test specimens . 6
7 Conditioning . 6
8 Procedure .7
9 Precision . 7
10 Test report . 7
Annex A (Informative) Comparison of VST results obtained with Liquid-filled Heating Bath
and Direct-contact heating unit .9
Annex B (Informative) Comparison of VST results obtained with Liquid-filled Heating Bath
and Fluidized Bed .11
Annex C (Informative) Repeatability and Precision .13
Bibliography .16
iii
© ISO 2021 – All rights reserved
---------------------- Page: 5 ----------------------
oSIST prEN ISO 306:2022
ISO/DIS 306:2021(E)
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
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
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).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee [or Project Committee] ISO/TC [or ISO/PC] 61,
Plastics, Subcommittee SC 2, Mechanical behaviour.
This sixth edition cancels and replaces the fifth edition (ISO 306:2013), several clauses have been edited.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
© ISO 2021 – All rights reserved
---------------------- Page: 6 ----------------------
oSIST prEN ISO 306:2022
ISO/DIS 306:2021(E)
Introduction
The main changes introduced with this revision of ISO 306 can be summarized as follows:
The document format and text are updated to allow for the use of commercial universal equipment (i.e.
covering both ISO 75 and ISO 306) and modern testing practices.
v
© ISO 2021 – All rights reserved
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oSIST prEN ISO 306:2022
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oSIST prEN ISO 306:2022
DRAFT INTERNATIONAL STANDARD ISO/DIS 306:2021(E)
Plastics — Thermoplastic materials — Determination of
Vicat softening temperature (VST)
1 Scope
1.1 This International Standard specifies four methods for the determination of the Vicat softening
temperature (VST) of thermoplastic materials:
— Method A50 using a force of 10 N and a heating rate of 50 °C/h
— Method B50 using a force of 50 N and a heating rate of 50 °C/h
— Method A120 using a force of 10 N and a heating rate of 120 °C/h
— Method B120 using a force of 50 N and a heating rate of 120 °C/h
1.2 The methods specified are applicable only to thermoplastics, for which they give a measure of the
temperature at which the thermoplastics start to soften rapidly.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 291, Plastics — Standard atmospheres for conditioning and testing
ISO 293, Plastics — Compression moulding of test specimens of thermoplastic materials
ISO 294-1, Plastics — Injection moulding of test specimens of thermoplastic materials — Part 1: General
principles, and moulding of multipurpose and bar test specimens
ISO 294-2, Plastics — Injection moulding of test specimens of thermoplastic materials — Part 2: Small
tensile bars
ISO 294-3, Plastics — Injection moulding of test specimens of thermoplastic materials — Part 3: Small
plates
ISO 472, Plastics — Vocabulary
ISO 2818, Plastics — Preparation of test specimens by machining
ISO 16012, Plastics — Determination of linear dimensions of test specimens
ISO 20753, Plastics — Test specimens
IEC 60584, Thermocouples (Parts 1 and 3)
IEC 60751, Industrial platinum resistance thermometers and platinum temperature sensors
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 472 and the following apply.
1
© ISO 2021 – All rights reserved
---------------------- Page: 9 ----------------------
oSIST prEN ISO 306:2022
ISO/DIS 306:2021(E)
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 https:// www .electropedia .org/
3.1
penetration
Distance over which the indention tip has to penetrate into the specimen under test
Note 1 to entry: It is expressed in millimetres (mm).
3.2
load
Force applied to test specimen by means of the indention tip
Note 1 to entry: It is expressed in Newtons (N).
3.3
Vicat softening temperature
VST
Temperature at which a flat-ended indenter will penetrate the specimen to a depth of 1 mm under a
specified load using a selected uniform rate of temperature rise
Note 1 to entry: It is expressed in degrees Celsius (°C).
4 Principle
The temperature at which a standard indenting tip with a flat point, under a standardized load,
penetrates 1 mm into the surface of a plastic test specimen is determined. The indenting tip exerts
a specified force perpendicular to the test specimen, while the specimen is heated at a specified and
uniform rate.
The temperature, in degree Celsius, of the specimen, measured as close as possible to the indented area
at 1 mm penetration, is quoted as the VST.
5 Apparatus
5.1 Means of producing penetration
The apparatus shall be constructed essentially as shown in Figure 1 (or Figure 2). It consists of a rigid
metal frame in which a rod can move freely in the vertical direction. One end of the rod is fitted with
a weight-carrying plate and the other end is equipped with an indenting tip. The base of the frame is
fitted with a support plate or other suitable load-application device.
Note 1 to entry It is recommended that the rod and frame(s) be constructed of low thermal expansion material.
Unless vertical parts of the apparatus have the same coefficient of linear thermal expansion, the difference in
change of length of these parts during the test introduces an error in the reading of the apparent penetration of
the test specimen.
A At calibration, a blank test shall be made on each-apparatus using a test specimen made of rigid
material having a low coefficient of expansion and a thickness comparable to that of the specimen
under test. The blank test shall cover the temperature ranges to be used in the actual determination,
and a correction term shall be determined for each temperature. If the correction term is 0,02 mm or
greater, its value and algebraic sign shall be recorded; and the term applied to each test result by adding
it algebraically to the reading of the apparent penetration of the test specimen.
Note 2 to entry Invar and borosilicate glass have been found suitable as materials for the test specimen in the
blank test.
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oSIST prEN ISO 306:2022
ISO/DIS 306:2021(E)
5.1.1 Indenter
It shall be made of hardened steel, at least 2 mm long, of circular cross-section and of area (1,000 ± 0,015)
2
mm (corresponding to an indenting tip diameter of (1,128 ± 0,008) mm) and fixed at the bottom of the
rod. The indenter, when in contact with the specimen, shall be perpendicular to the rod. The tip shall be
free from burrs or other imperfections.
5.2 Heating equipment
The heating equipment shall be a heating bath containing a suitable liquid, a fluidized bed, or a direct
contact heating unit, see Figure 2. For heat transfer media other than gas (air) the test specimen shall
be immersed to a depth of at least 35 mm.
An efficient stirrer or means to fluidize the solid heat transfer medium shall be provided. If liquids are
used for heat transfer, it shall be established that the liquid chosen is stable over the temperature range
used and does not affect the material under test, for example causing it to swell or crack.
The method using a liquid heat transfer medium shall be considered a reference method in case of
doubts or conflicts, if possible, in the temperature range under consideration.
The heating equipment shall be provided with a control unit so that the temperature can be raised at a
uniform rate of (50 ± 5) °C/h or (120 ± 10) °C/h.
The heating rate shall be verified periodically either by checking the automatic temperature reading, or
manually checking the temperature at least every 6 min. The requirement for the heating rate shall be
considered satisfied if, over every 6 min interval during the test, the temperature change is (5,0 ± 0,5)
°C/h or (12,0 ± 1,0) °C/h.
It is allowable for the first 10 min or up to 40°C of the ramp to be outside of the prescribed tolerances as
many instruments use a PID control for the heating, and it is normal for the controller to tune itself to
the correct power and interval requirements to perform the required ramp rate.
Note 1 to entry A means of accelerating the cooling rate of the heating equipment has been found to be desirable
Note 2 to entry Liquid paraffin, transformer oil, glycerol and silicone oils are suitable liquids, but others may be
used. For fluidized beds, aluminium oxide powder has been found suitable.
5.3 Weights
A set of weights shall be provided so that the total load applied to the test specimen is (10 ± 0,2) N for
methods A50 and A120 or (50 ± 1,0) N for methods B50 and B120.
5.4 Temperature-measuring instrument
Use a suitable temperature-measuring instrument of appropriate range and maximum error limit
of ± 1 °C. The temperature-measuring instruments shall be calibrated at the depth of immersion
particular to the apparatus in use and in a temperature range that comprises the Vicat softening
temperatures to be measured. The temperature-sensing part of the instrument shall be located not
farther than 20 mm from the point where the indenting tip contacts the specimen. The temperature
sensing part of the instrument shall not touch the specimen or be in contact with any part of the frame.
Note 1 to entry Calibration of the temperature-measuring instrument can be performed by static calibration
(at one or more constant temperatures) or by dynamic calibration (using a constant heating-rate). Dynamic
calibration is capable of measuring temperature lag of the build-in temperature measuring device but requires a
reference temperature measuring device with suitable dynamic properties.
Thermocouples shall comply with the requirements of IEC 60584. Resistance thermometers shall
comply with the requirements of IEC 60751.
It is recommended that the heating bath is equipped with a separate temperature-measuring
instrument at each test station if there are several.
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oSIST prEN ISO 306:2022
ISO/DIS 306:2021(E)
Key
1 penetration-measuring device 5 approximate level of liquid or fluidized
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