Iec 60763 2 2007

The test specimens shall be conditioned in accordance with Clause 3 and the thickness of each measured at a point near the centre of each test specimen.. The set of test specimens giving

Method A (preferable)

Test specimens must be dried in an oven with forced air circulation at 105 °C ± 2 K for 24 ± 1 hours, followed by drying in a vacuum chamber at the same temperature for 48 ± 2 hours, maintaining a residual pressure of no more than 1 kPa After drying, the specimens should be cooled in a desiccator before testing.

Method B

Test specimens shall be dried in a ventilated oven at 105 °C ± 2 K for (168 ± 8) h at atmospheric pressure When test pieces of the specified size are dried according to method

B, test results similar to the test results obtained after drying according to method A may be expected

Thickness

An external screw-type micrometer with measuring faces ranging from 6 mm to 8 mm in diameter will be utilized for testing The measuring faces must be flat within 0.001 mm and parallel within 0.003 mm This micrometer should be graduated in 0.01 mm divisions and possess an accuracy of ± 0.005 mm The pressure applied to the specimens will be set at 0.1 MPa.

The thickness of the laminated pressboard sheet must be measured to the nearest 0.01 mm in its as-received condition, with measurements taken at eight points—two along each edge, ensuring that they are at least 20 mm away from the edge.

In the event of a dispute, a strip measuring 40 ± 1 mm in width will be cut from the full width of the sheet From this strip, eight test specimens, each at least 40 mm long and cut from equally spaced positions, will be prepared These specimens must be conditioned as per Clause 3, and their thickness will be measured near the center of each specimen.

The central value of the eight measurements shall be taken as the result, and the minimum and maximum values obtained shall be reported

LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU.

When a laminated pressboard sheet is positioned concave side up on a flat surface without restraint, the deviation of the upper surface from a straight edge measuring (1000 ± 10) mm or (500 ± 5) mm, placed in any direction, must not exceed the limits specified in IEC 60763-3, which are determined by the material, thickness, and length of the straight edge.

The mass of the straight edge shall not exceed (500 ± 5) g

Flexural strength and load to produce a standard deflection

The test shall be carried out with the load applied perpendicular to the laminations

Rectangular strips measuring 20 ± 1 mm in width and at least 20 times the measured thickness in length should be utilized The thickness corresponds to that of the board being tested; however, if the measured thickness of a test piece exceeds 20 mm, the thickness must be adjusted accordingly.

(20 ± 1) mm, one face of the test piece being left intact

Five tests shall be carried out on specimens cut in machine direction (direction A) and five in cross-machine direction (direction B) (See definitions of directions A and B given in Figure 1.)

To determine the machine direction of a sheet, cut five specimens with their length parallel to one edge and five specimens at a right angle The set of specimens that exhibits the highest flexural strength is considered to be aligned with the machine direction.

The universal testing apparatus is engineered to bend a test specimen of specified dimensions at a consistent rate, while accurately measuring the force and deflection at the midpoint This test rig is essential for determining the three-point bending strength of materials.

Test specimens shall be dried in accordance with Clause 4

After cooling in a desiccator, the test specimen's width must be measured immediately with an accuracy of ± 0.1 mm, while the thickness should be measured with an accuracy of ± 0.02 mm Subsequently, the specimen should be positioned lengthwise and symmetrically across two parallel supports.

Where one surface has been removed, the original, intact surface shall rest on the two supports

The surfaces of the supports in contact with the test specimen must have a radius of (5 ± 0.2) mm The distance between the supports should be 16 times the nominal thickness of the test specimen, measured with an accuracy of ± 0.5% A loading member, parallel to and positioned midway between the supports, will apply the load across the width of the test specimen, with the end radius of the loading member also being (5 ± 0.2) mm.

The load will be gradually increased from zero to failure through the relative movement of the loading member and supports at a consistent rate This movement rate, corresponding to the deflection of the midpoint of the test specimen, shall be maintained at (5 ± 0.5) mm/min.

The load at a standard deflection of 0,4 mm shall be noted

The maximum load shall be noted

The flexural strength σ f in MPa of the test specimen shall be calculated as follows: ²

F is the maximum load (in N);

L is the distance between the supports (in mm); b is the width of the test specimen (in mm); h is the thickness of the test specimen (mm)

The flexural strength and the load required to achieve standard deflection in both the machine and cross-machine directions should be reported as the average of results obtained from five test specimens cut in each direction.

Apparent modulus of elasticity in flexure

The apparent modulus of elasticity in flexure E in MPa can be calculated from the load at

0,4 mm deflection according to 6.1.4 using the following formula:

L is the distance between the supports (in mm); b is the width of the test specimen (in mm); h is the thickness of the test specimen (in mm);

F is the load at deflection of 0,4 mm (in N)

The apparent modulus of elasticity in flexure must be reported for both the machine and cross-machine directions, reflecting the central value derived from five test specimens cut in each direction.

Principle

To assess the compressibility of laminated pressboard, a series of test samples will be exposed to an initial low pressure, known as bedding pressure, before being subjected to a specified final pressure The compressibility of the material is quantified by measuring the percentage change in the thickness of the pad.

The pressure will be reduced back to the bedding pressure, and the percentage changes in the pad's thickness will enable the calculation of the material's reversible and residual compressibility.

Test apparatus

The universal testing apparatus is engineered to compress a test specimen of specified dimensions at a consistent rate, while accurately measuring both the compressive force and the deflection of the specimen This test rig features parallel steel plates, aligned within 0.2 mm, and has a surface area larger than that of the test piece.

Test pieces

A sufficient number of square test pieces with an edge length of (25 ± 0,5) mm shall be cut

The selection of test pieces must allow for the creation of three stacks with heights ranging from 25 mm to 85 mm For materials exceeding 85 mm in thickness, specimens should be machined on one face to achieve a thickness of (85 ± 0.25) mm It is essential that all edges of the test specimens are free from burrs, and the test pieces must be dried according to Clause 4.

Procedure

A stack of test pieces shall be placed between the plates of the test rig A bedding pressure of

(1 ± 0,1) MPa shall be applied for at least 5 min and then the height h 0 of the stack shall be measured with an accuracy of ± 0,1 mm

The pressure will be set to (20 ± 0.1) MPa, with the moving plate displaced at a rate of (5 ± 1) mm per minute This pressure must be sustained for a minimum duration of 5 minutes.

The difference in height Δh 1 from h 0 of the stack shall be measured with an accuracy of ±0,01 mm

The pressure shall be reduced to (1 ± 0,1) MPa and kept for not less than 5 min

The difference in height Δh 2 from h 0 of the stack shall be measured with an accuracy of ± 0,01 mm after the bedding pressure has been restored.

Results

The following calculated values shall be reported

Residual amount of the compressibility (in %):

Reversible amount of the compressibility (in %):

All three values shall be reported The central value shall be taken as the result

General and conditioning

Electric strength is determined according to IEC 60243-1, with testing conducted in mineral oil Class II at a temperature of 23 °C ± 2 K Specimens must be dried and oil-impregnated as per the oil absorption test, requiring a vacuum drying time of (48 ± 4) hours This process occurs after machining, and it is crucial that specimens remain protected from atmospheric exposure between impregnation and testing.

Electric strength along laminate (edgewise electric strength)

8.2.1 Method 1 for materials with a thickness of more than 25 mm

Five specimens shall be tested The size of the test specimens and the arrangements of the electrodes shall be as shown in Figure 2

The cylindrical electrodes shall be (6 ± 0,1) mm in diameter and have hemispherical ends

Each hole shall be not more than 0,1 mm greater in diameter than each electrode diameter

Alternative forms of vented electrodes are shown in Figure 3 When electrodes with slots are used, these slots shall be diametrically opposed to the gap between the electrodes

The holes shall be pre-drilled by a normal point-ground drill down to the outermost glue-layer

The final drilling must be performed using a specially ground, well-sharpened drill with a radius of (3 ± 0.1) mm to ensure the outermost glue layer is penetrated without causing mechanical or thermal stress to the test specimen Care must be taken to prevent the drill from breaking through this outer layer Voltage application should follow section 9.1 of IEC 60243-1, with the breakdown voltage recorded as the result The report should include the central value from five tests as well as the lowest value obtained.

8.2.2 Method 2 for materials with a thickness between 10 mm and 25 mm

Five specimens will be tested, each cut to full thickness with dimensions of (10 ± 0.2) mm in width and (50 ± 1) mm in length, ensuring that the planes are parallel and perpendicular to the material's surface The electrodes used will conform to Figure 6 of IEC 60243-1, and the voltage application will follow the guidelines outlined in section 9.1 of IEC 60243-1.

The breakdown voltage shall be taken as the result The central value of the five tests and the lowest value shall be reported

9 Internal ply strength, thermal resistance and oil compatibility

Principle

The test consists of determining the change of flexural strength of the material at room temperature and at 120 °C and before and after ageing in oil.

Test specimens

Rectangular strips measuring (10 ± 1) mm in width and (10 ± 0.5) times the measured thickness will be utilized The thickness of these strips will match that of the board being tested; however, if the measured thickness of a test piece exceeds 15 mm, the thickness will be adjusted accordingly.

(15 ± 0,5) mm, one face of the test piece being left intact

Twenty test specimens cut in machine direction and 20 test specimens cut in cross- machine direction shall be prepared.

Test apparatus

The universal testing apparatus is engineered to bend a test specimen of specified dimensions at a consistent rate, while accurately measuring the force and deflection at the midpoint This test rig is essential for determining the three-point bending strength of materials.

Procedure

All the specimens shall be dried according to Clause 4, Method A Twenty of the dried specimens shall be tested as indicated in Table 1

The rest of the specimens shall be oil-impregnated according to 13.2 Ten oil-impregnated specimens shall be tested according to Table 1

The oil vessel containing 10 test specimens will be placed in a forced air circulation oven set at 120 °C ± 2 K and covered with aluminum foil After approximately 168 hours, the heating will be turned off, allowing the oil to cool to ambient temperature Subsequently, the ten aged samples will be tested as outlined in Table 1.

Table 1 – Number of test specimens

Orientation of the board Dried Oil-impregnated Oil-impregnated and aged

Determination of the flexural strength

The test will be conducted with the load applied perpendicular to the laminations After cooling in a desiccator, the width of the test specimen will be measured with an accuracy of ± 0.1 mm, and the thickness will be measured with an accuracy of ± 0.02 mm The specimen must then be placed symmetrically across two parallel supports, ensuring that the original, intact surface rests on the supports if one surface has been removed.

The supports in contact with the test specimen must have a radius of (5 ± 0.2) mm The distance between the supports should be (6.6 ± 0.2) times the nominal thickness of the test specimen, measured with an accuracy of 0.5% A uniform load is to be applied across the width of the test specimen using a loading member that is parallel to and positioned midway between the supports, with the radius of the loading member's end being (5 ± 0.1) mm.

The load must be gradually increased from zero through the relative movement of the loading member and supports at a consistent rate This movement rate, corresponding to the deflection of the midpoint of the test specimen, should be maintained at (5 ± 0.5) mm/min.

The maximum load shall be noted

The location of the rupture – within pressboard, within glue line, interface board/glue – shall be noted.

Results

The flexural strength σf in MPa of the test specimen shall be calculated as follows:

LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU. ² bh

F is the maximum load (in N);

L is the distance between the supports (in mm); b is the width of the test specimen (in mm); h is the thickness of the test specimen (in mm)

The internal ply adhesion is indicated by the location of the rupture

The thermal resistance is expressed in terms of percentage retention of the measured flexural strength of the dry samples tested at 120 °C relative to the strength at 23 °C

Oil compatibility is quantified by the percentage retention of the properties of oil-impregnated samples at 23 °C compared to the properties of dry samples tested under the same conditions.

The resistance of oil to aging is quantified by the percentage retention of its properties when samples are aged at 120 °C, compared to the properties of non-aged, oil-impregnated samples.

The central values of the thermal resistance, the oil compatibility and the resistance to ageing shall be taken as the results

Test specimens

The test shall be carried out on three conditioned test pieces; one determination shall be made on each of the three test pieces

Rectangular test pieces of an area not less than 100 cm 2 shall be used.

Procedure

The mass of the test specimen shall be measured to an accuracy of 10 –4 × the mass of the test piece

Two measurements of the length and two of the width of each test piece to an accuracy of

0,1 mm shall be made at points at least 12 mm from the corners

The thickness shall be determined by making eight measurements as indicated in 5.1 and the mean value of the measurements calculated.

Results

The apparent density ρ (the mass to volume ratio) shall be expressed as g/cm3

= × w l s ρ m where m is the mass, in g;

This document is licensed to MECON Limited for internal use at the Ranchi and Bangalore locations, and it has been supplied by the Book Supply Bureau The mean thickness is represented by $ s $ (in mm), while $ l $ denotes the mean of the two length measurements (in mm), and $ w $ indicates the mean of the two width measurements (in mm).

All three values shall be reported The central value shall be taken as the result

The moisture content in the as-received condition shall be measured according to a method based on ISO 287

Three test specimens, each with a minimum mass of 50 g and ideally sized at 100 mm × 25 mm × original thickness, should be accurately weighed to ±1 mg After drying and cooling as per Clause 3, they must be reweighed with the same precision The moisture content is calculated as the mass loss expressed as a percentage of the original mass The average of the three measurements will be reported as the result, along with the other two values.

12 Shrinkage in air after drying

Test specimens

Six specimens measuring approximatly 50 mm × 300 mm shall be cut, three being in machine direction A and three in cross-direction B (see Figure 1).

Procedure

After conditioning the specimens as per Clause 3, measure the length and thickness of each specimen The thickness measurement should be taken at least 20 mm from the edge.

The specimens shall then be dried in accordance with Clause 4

After allowing the sample to cool to room temperature in a desiccator, it is essential to measure its length and thickness once more The length should be recorded with an accuracy of ± 0.05 mm, while the thickness must be measured with an accuracy of ± 0.01 mm.

Results

Shrinkage in length for directions A and B will be determined by calculating the percentage change in the dimensions of the original measurements of the conditioned test specimens The central value for each direction will be reported as the result, along with the other two values For thickness shrinkage, the central value will be the result, while the highest and lowest values will also be documented.

Test specimens

The test shall be carried out on three specimens each 100 mm × 25 mm and of the same thickness as the material under test.

Procedure

The specimens shall be dried in accordance with Clause 4, Method A, and the mass then determined to the nearest milligram

The specimens shall be placed in a vacuum chamber, the temperature raised to 90 °C ± 2 K and the pressure reduced to not more than 1 kPa

The temperature and pressure must be sustained for one hour Subsequently, oil that meets Class II standards in IEC 60296, preheated to 90 °C ± 2 K, should be introduced at a controlled rate to prevent the pressure from exceeding 2.5 kPa.

To ensure accurate measurements, fully submerge the specimens, using sinkers if needed, and allow the pressure to gradually return to atmospheric levels before turning off the heating Leave the specimens in oil for a duration of (24 ± 1) hours After this period, remove the specimens from the oil and use blotting paper to eliminate any excess oil Finally, weigh the clean specimens with the same precision as before to determine the mass of the absorbed oil.

Results

The results will be presented as the percentage of oil mass absorbed compared to the original mass of the dried samples The average of the three measurements will be considered the final result, while the other two measurements will also be documented.

Procedure

The residue remaining after incineration of the material in its as-received condition must be measured following the ISO 2144 method A minimum specimen mass of 5 g is required, and the sample should accurately reflect the glue/cellulose ratio of the board being tested A total of three determinations should be conducted.

Results

The central value obtained shall be taken as the result, based on oven-dry material

(calculated from determination of moisture content according to 9.3); the highest and lowest values are reported

Apparatus

– A conductivity cell according to IEC 60247

– A cell for the determination of the dissipation factor of liquids according to IEC 60250

– A vessel to contain oil, of neutral or borosilicate glass with a volume of at least 1 l in which an atmosphere of dry nitrogen may be maintained above the oil

– An oven with forced air circulation, controllable to 100 °C ± 1 K

– Dry oil (Class II of IEC 60296) whose neutralization value and dissipation factor at 90 °C and 48 Hz to 62 Hz have been determined

NOTE Cells of Figures 2 and 3 of IEC 60250 are also usable for resistivity measurement and accordingly described in IEC 60247.

Test specimens

For optimal results, ensure that the material is finely cut into pieces smaller than 1 mm, with a surface area of approximately 1 cm², and dried at 105 °C ± 2 K for at least 16 hours Handle the specimens using clean metal tongs to maintain their integrity.

Procedure

In a controlled environment, immerse (75 ± 0.1) g of specimens in (750 ± 5) cm³ of oil, ensuring the vessel's cleanliness Maintain a dry nitrogen atmosphere above the oil Heat both the specimen-containing vessel and an identical blank vessel with the same oil at 100 °C ± 1 K for (168 ± 4) hours.

After this period, the neutralization value according to IEC 62021-1, the sludge content according to IEC 61125 and the dissipation factor according to IEC 60247 at 90 °C ±1 K and

48 Hz to 62 Hz shall be measured for both the test oil and the blank.

Results

The difference between the two values obtained shall be taken as the result

Procedure

The test will be conducted according to IEC 60641-2, ensuring that the glue/cellulose ratio accurately represents the entire thickness of the board If strips are utilized, they should not exceed dimensions of 20 mm × 3 mm, although smaller subdivisions may be employed as long as the glue/cellulose ratio is preserved.

Results

The conductivity shall be expressed in millisiemens per metre (mS/m)

The test shall be carried out as described in IEC 60641-2 but using an extract prepared as in

Figure 1 – Position of test specimen in relation to length, width and thickness of sheet

Figure 2 – Size of the test specimens and arrangement of the electrodes for testing the electric strength along laminae (edgewise electric strength)

Figures 3 and 4 – Alternative forms of vented electrodes

6.1 Résistance à la flexion et contrainte produisant une flèche conventionnelle 27

6.2 Module d'élasticité apparent à la flexion 28

8.2 Rigidité diélectrique le long des lignes de colle (rigidité diélectrique sur l’arête) 30

8.2.1 Méthode 1 pour matériaux d'épaisseur supérieure à 25 mm 30

8.2.2 Méthode 2 pour matériaux d'épaisseur comprise entre 10 mm et 25 mm 30

9 Résistance à la traction des couches internes, résistance thermique et compatibilité avec l’huile 30

9.5 Détermination de la résistance à la flexion 31

12 Retrait dans l'air après séchage 33

Figure 1 – Position de l’éprouvette d’essai en fonction de la longueur, de la largeur et de l’épaisseur de la feuille 36

Figure 2 – Taille des éprouvettes d’essai et disposition des électrodes pour l’essai de rigidité diélectrique le long des lignes de colle (rigidité diélectrique sur l’arête) 36

Figures 3 et 4 – Autres formes d'électrodes munies d'un orifice de sortie 37

SPÉCIFICATION POUR CARTONS COMPRIMÉS ET CONTRECOLLÉS –

The International Electrotechnical Commission (IEC) is a global standardization organization comprising national electrotechnical committees Its primary goal is to promote international cooperation on standardization issues in the fields of electricity and electronics To achieve this, the IEC publishes international standards, technical specifications, technical reports, publicly accessible specifications (PAS), and guides, collectively referred to as "IEC Publications." The development of these publications is entrusted to study committees, which allow participation from any interested national committee Additionally, international, governmental, and non-governmental organizations collaborate with the IEC in its work The IEC also works closely with the International Organization for Standardization (ISO) under conditions established by an agreement between the two organizations.

Official decisions or agreements of the IEC on technical matters aim to establish an international consensus on the topics under consideration, as the national committees of the IEC involved are represented in each study committee.

The IEC publications are issued as international recommendations and are approved by the national committees of the IEC The IEC makes every reasonable effort to ensure the technical accuracy of its publications; however, it cannot be held responsible for any misuse or misinterpretation by end users.

To promote international consistency, the national committees of the IEC commit to transparently applying IEC publications in their national and regional documents as much as possible Any discrepancies between IEC publications and corresponding national or regional publications must be clearly stated in the latter.

5) La CEI n’a prévu aucune procédure de marquage valant indication d’approbation et n'engage pas sa responsabilité pour les équipements déclarés conformes à une de ses Publications

6) Tous les utilisateurs doivent s'assurer qu'ils sont en possession de la dernière édition de cette publication

The IEC and its administrators, employees, agents, including external experts and members of its study committees and national committees, shall not be held liable for any injuries, damages, or any other type of loss, whether direct or indirect This includes any costs or expenses, such as legal fees, arising from the publication or use of this IEC Publication or any other IEC Publication, or from the credit attributed to it.

8) L'attention est attirée sur les références normatives citées dans cette publication L'utilisation de publications référencées est obligatoire pour une application correcte de la présente publication

Attention is drawn to the fact that some elements of this IEC publication may be subject to intellectual property rights or similar rights The IEC cannot be held responsible for failing to identify such property rights or for not indicating their existence.

La Norme internationale CEI 60763-2 a été établie par le comité d’études 15 de la CEI:

Cette deuxième édition annule et remplace la première édition publiée en 1991 et constitue une révision technique

La présente édition comporte les modifications techniques significatives suivantes par rapport à l’édition précédente a) D’une manière générale, la norme a été révisée et mise en conformité avec la

The CEI 60641-2 standard has undergone revisions, including the replacement of the testing method for determining the tensile strength of internal layers with a new approach Additionally, the scope of the testing method for assessing thermal resistance has been expanded.

La présente version bilingue, publiée en 2009-06, correspond à la version anglaise

Le texte anglais de cette norme est issu des documents 15/360/FDIS et 15/373/RVD

Le rapport de vote 15/373/RVD donne toute information sur le vote ayant abouti à l'approbation de cette norme

La version franỗaise de cette norme n’a pas ộtộ soumise au vote

La liste de toutes les parties de la CEI 60763, sous le titre général Spécification pour cartons comprimés et contrecollés, est disponible sur le site web de la CEI

The committee has determined that the content of this publication will remain unchanged until the maintenance date specified on the IEC website at "http://webstore.iec.ch" in the data related to the publication in question At that time, the publication will be updated.

• remplacée par une édition révisée, ou

La présente Norme internationale traite des cartons comprimés et contrecollés définis à l’Article 2 de la CEI 60763-1

La CEI 60641 est applicable aux cartons comprimés non contrecollés; le matériau couvert par la présente Norme internationale est constitué de feuilles conformes aux exigences de cette publication

SPÉCIFICATION POUR CARTONS COMPRIMÉS ET CONTRECOLLÉS –

La présente partie de la CEI 60763 expose les méthodes d'essai applicables aux matériaux classés dans la CEI 60763-1

Les documents référencés suivants sont indispensables à l’application du présent document

Pour les références datées, seule l’édition citée s’applique Pour les références non datées, la dernière édition du document référencé (y compris ses amendements) s’applique

CEI 60243-1:1998, Rigidité diélectrique des matériaux isolants – Méthodes d’essai – Partie 1:

CEI 60247:2004, Liquides isolants – Mesure de la permittivité relative, du facteur de dissipation diélectrique (tan δ) et de la résistivité en courant continu

CEI 60250:1969, Méthodes recommandées pour la détermination de la permittivité et du facteur de dissipation diélectrique des isolants électriques aux fréquences industrielles, audibles et radioélectriques (ondes métriques comprises)

CEI 60296:2003, Fluides pour applications électrotechniques – Huiles minérales isolantes neuves pour transformateurs et appareillages de connexion

CEI 60641-2:2004, Carton comprimé et papier comprimé à usages électriques – Partie 2:

CEI 60763-1:1983, Spécification pour cartons comprimés et contrecollés – Partie 1:

Définitions, classification et prescriptions générales

CEI 61125:1992, Isolants liquides neufs à base d’hydrocarbures – Méthodes d’essai pour évaluer la stabilité à l’oxydation

CEI 62021-1:2003, Liquides isolants – Détermination de l’acidité – Partie 1: Titrage potentiométrique automatique

ISO 287:1985, Papier et carton – Détermination de l’humidité – Méthode par séchage à l’étuve

ISO 2144:1997, Papier, carton et pâtes – Détermination du résidu (cendres) après incinération à 900 degrés C

Given that the packaging of compressed and laminated cartons is time-consuming, the material is tested in its delivery state or dried The material must be packaged according to the following procedure only in the event of a dispute.

Conditioning should be performed at a temperature of 23 °C ± 2 K and a relative humidity of (50 ± 5) % until the moisture content of the sample is between 5.5 % and 8 % After drying at 70 °C ± 5 K, the conditioning process should lean towards the dry side to ensure that the conditioning atmosphere results in an increase in the mass of the sample.

Test specimens must be dried at 105 °C ± 2 K for (24 ± 1) hours in a forced ventilation oven, followed by drying at the same temperature for (48 ± 2) hours in a vacuum chamber with a residual pressure of 1 kPa or less After this process, the specimens should be removed and allowed to cool in a desiccator before testing.

Les éprouvettes d’essai doivent être séchées dans une étude à ventilation forcée à 105 °C ±

The 2 K pendant is tested for 168 ± 8 hours at atmospheric pressure When specimens of the specified size are dried using method B, the test results are expected to be similar to those obtained after drying with method A.

A micrometer with an external screw and contact points measuring 6 mm to 8 mm in diameter should be utilized for testing These contact points must be flat within 0.001 mm and parallel within 0.003 mm The micrometer should be graduated in divisions of 0.01 mm and have a precision of ±.

0,005 mm La pression exercée sur les éprouvettes doit être de 0,1 MPa à 0,3 MPa

The thickness of the compressed and laminated cardboard must be measured to an accuracy of 0.01 mm upon delivery Measurements should be taken at eight points, with two points along each edge, ensuring that they are no less than 20 mm from the edge.

In the event of a dispute, a strip measuring 40 ± 1 mm in width must be cut across the entire width of the sheet, from which eight specimens should be evenly cut, each with a minimum length of 40 mm The specimens must be prepared in accordance with Article 3, and the thickness of each specimen should be measured at a point close to its center.

Le résultat doit être la valeur médiane des huit mesures, les valeurs minimale et maximale obtenues devant également être consignées

Mode opératoire

La masse de l’éprouvette doit être déterminée avec une précision de 10 –4 × la masse de l’éprouvette

Deux mesures de la longueur et de la largeur de chaque éprouvette doivent être réalisées à

0,1 mm près en des points distants d’au moins 12 mm des coins

L’épaisseur doit être déterminée par huit mesures (voir 5.1) et la valeur moyenne des mesures calculée.

Résultats

La masse volumique apparente ρ (masse sur volume) doit être exprimée en g/cm3

The formula for mass, denoted as \$m\$, is calculated using the average thickness (\$s\$ in mm), the average length (\$l\$ in mm), and the average width (\$w\$ in mm), with the density represented by \$\rho\$ Specifically, the mass in grams is determined by the equation \$m = w \times l \times s \times \rho\$.

Les trois valeurs doivent être reportées Le résultat doit être la valeur médiane

La teneur en humidité du matériau en l'état de réception doit être mesurée conformément à l’ISO 287

Three test tubes, each with a mass of at least 50 g and dimensions preferably measuring 100 mm × 25 mm with original thickness upon receipt, must be weighed with a precision of ± 1 mg They should then be dried and cooled according to the guidelines in Article 3, followed by a reweighing with the same precision The moisture content is defined as the mass loss expressed as a percentage of the original mass The median value of the three measurements should be recorded as the result, while the other two values must also be documented.

12 Retrait dans l'air après séchage

Eprouvettes d’essai

L'essai porte sur six éprouvettes d’environ 50 mm × 300 mm, trois devant être prélevées dans le sens machine A et trois dans le sens transversal B (voir Figure 1).

Mode opératoire

The test tubes, having been prepared according to the specifications of Article 3, must have their length and thickness measured with a single measurement for each dimension, ensuring that the thickness is taken at least 20 mm from the edges.

Les éprouvettes doivent alors être séchées conformément aux indications de l'Article 4

After cooling in a desiccator to room temperature, the length and thickness must be measured again The length before and after drying should be measured with an accuracy of ± 0.05 mm, and the thickness should be measured with an accuracy of ± 0.01 mm.

Résultats

The length shrinkage should be calculated in both directions A and B as the percentage variation of the dimensions compared to the original measurements taken on the conditioned samples For each direction, the median value should be recorded as the result, while the other two values must be documented In terms of thickness shrinkage, the median value should represent the desired result, with the minimum and maximum values also being noted.

L’essai doit être réalisé sur trois éprouvettes de 100 mm × 25 mm et dont l’épaisseur est celle du matériau soumis à essai.

Mode opératoire

Les éprouvettes doivent être séchées conformément à l’Article 4, Méthode A, et la masse déterminée au milligramme près

Les éprouvettes doivent être placées dans une enceinte à vide, la température élevée à 90 °C ± 2 K et la pression inférieure ou égale à 1 kPa

The temperature and pressure must be maintained for one hour An oil that meets the requirements of Class II of IEC 60296, preheated to 90 °C ± 2 K, should then be introduced slowly enough to keep the pressure at or below the specified limit.

When the specimen is fully submerged, using a weight if necessary, the pressure should be gradually increased to atmospheric pressure, and heating should be stopped The specimens must be left in the oil for (24 ± 1) hours After this period, the specimens should be removed from the oil, and any excess oil should be absorbed with blotting paper The clean specimens should then be weighed with the same precision as before to determine the mass of the absorbed oil.

Résultats

The results should be expressed as a percentage of the oil mass absorbed relative to the original mass of the dried samples The final result must be the median value of the three measurements, with the other two values recorded.

Mode opératoire

La quantité du résidu subsistant après incinération du matériau à l'état de livraison doit être déterminée selon la méthode décrite dans l'ISO 2144 La masse des éprouvettes doit être de

5 g au moins Elles doivent être choisies de manière à obtenir un rapport colle/cellulose représentatif du carton soumis à essai L'essai doit porter sur trois mesures.

Résultats

The result should be the median value derived from the mass of the material dried in the oven, calculated based on the moisture content determination as outlined in section 9.3 Both the highest and lowest values are recorded.

Appareillage

– Une cellule de conductivité selon les exigences de la CEI 60247

– Une cellule pour la détermination du facteur de dissipation diélectrique des liquides conformément à la CEI 60250

– Un récipient en verre neutre ou borosilicaté pour contenir l'huile, d'un volume d'au moins

1 l dans lequel une atmosphère d'azote sec peut être maintenue au-dessus de l'huile

– Une étuve à ventilation forcée pouvant être régulée à 100 °C ± 1 K

– De l'huile sèche (classe II de la CEI 60296) dont la valeur de neutralisation et le facteur de dissipation à 90 °C entre 48 Hz à 62 Hz ont été déterminés

NOTE Les cellules représentées aux Figures 2 et 3 de la CEI 60250 sont également utilisables pour les mesures de résistivité et sont décrites comme telles dans la CEI 60247.

Une quantité suffisante de matériau découpé en morceaux d'épaisseur inférieure à 1 mm, dont la surface est voisine de 1 cm 2 et qui a été séchée à 105 °C ± 2 K pendant au moins

16 h Les éprouvettes doivent être manipulées avec des pinces métalliques propres.

Mode opératoire

(75 ± 0,1) g d’éprouvette doivent être immergés dans le récipient dans (750 ± 5) cm 3 d’huile

It is advisable to first check the cleanliness of the specified container A dry nitrogen atmosphere should be maintained above the oil The container holding the oil, along with a test tube and an identical container serving as a control with only oil, must be heated to 100 °C ± 1 K for a duration of (168 ± 4) hours.

At the end of the heating period, the neutralization index value must comply with IEC 62021-1, the sludge content should meet the standards of IEC 61125, and the dissipation factor must align with IEC 60247 for both the test oil and the reference oil at a temperature of 90 °C ±.

1 K entre 48 Hz et 62 Hz doivent être mesurés.

Résultats

Le résultat doit être la différence entre les deux valeurs obtenues

Mode opératoire

This test must be conducted in accordance with IEC 60641-2 standards, ensuring that the samples are taken to achieve a representative adhesive to cellulose ratio relative to the total thickness of the cardboard If strips are utilized, they should not exceed dimensions of 20 mm.

3 mm, mais il est possible de prendre des morceaux plus petits à condition que le rapport colle/cellulose soit conservé.

Résultats

La conductivité doit être exprimée en millisiemens par mètre (mS/m)

Cet essai doit être effectué selon les dispositions de la CEI 60641-2 sur un extrait préparé comme indiqué en 16.1

LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU. b h h b

Figure 1 – Position de l’éprouvette d’essai en fonction de la longueur, de la largeur et de l’épaisseur de la feuille

Figure 2 – Taille des éprouvettes d’essai et disposition des électrodes pour l’essai de rigidité diélectrique le long des lignes de colle (rigidité diélectrique sur l’arête)

Figures 3 et 4 – Autres formes d'électrodes munies d'un orifice de sortie

Tiêu đề	Specification for Laminated Pressboard – Part 2: Methods of Test
Trường học	Not specified
Chuyên ngành	Electrical Standards and Testing Methods
Thể loại	International Standard
Năm xuất bản	2007
Thành phố	Geneva

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Số trang	42
Dung lượng	1,04 MB