GB/T Translated English of Chinese Standard: GB/T NATIONAL STANDARD

Transcription

1 Translated English of Chinese Standard: GB/T GB NATIONAL STANDARD OF THE PEOPLE S REPUBLIC OF CHINA ICS G 40 GB/T Replacing GB/T Rubber, vulcanized or thermoplastic Determination of the effect of liquids 硫化橡胶或热塑性橡胶耐液体试验方法 (ISO 1817:2005, Rubber, vulcanized Determination of the effect of liquids, MOD) Issued on: January 14, 2011 Implemented on: December 01, 2011 Issued by: General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China; Standardization Administration of the People's Republic of China. Page 1 of 28

2 Table of contents Foreword... 3 Introduction Scope Normative references Test device Test liquids Test pieces Temperature and duration of test liquid immersion Procedures Test report Appendix A (Normative) Reference liquid Appendix B (Normative) Reference liquid Page 2 of 28

3 Foreword This standard was drafted in accordance with the rules given in GB/T This standard replaces GB/T Rubber, vulcanized or thermoplastic - Determination of the effect of liquids. As compared with GB/T , the main technical differences of this standard are as follows: - ADD a test piece type of measuring of volume changes and mass changes, type II: 25 mm x 25 mm square (SEE 5.2); - CORRECT the equation (1) into - ADD an equation (SEE 7.3); (SEE 7.2); - ADD the Appendix B Reference liquid, in order to specify the main performance of domestic No.1, 2, and 3 standard oils. This standard, through the re-drafting method, modifies and adopts ISO 1817:2005 Rubber, vulcanized - Determination of the effects of liquids (English version). The technical differences between this standard and ISO 1817:2005 AND their causes are as follows: - CHANGE the standard name into Rubber, vulcanized or thermoplastic - Determination of the effect of liquids, because the standard scope had included the thermoplastic rubber. - On the normative references, this standard has made adjustments with technical differences, in order to adapt to the technical conditions in China, AND the adjustments are centrally reflected in Chapter 2 Normative references, which are detailed as below: USE the GB/T 262 which had modified and adopted international standard to replace ISO 2977 (SEE Table A.3 and Table B.1); USE the GB/T 528 which had equivalently adopted international standard to replace ISO 37 (SEE 5.2 and 7.7); Page 3 of 28

4 Introduction The action of a liquid on vulcanized or thermoplastic rubber can generally result in: a) Absorption of the liquid by the rubber; b) Extraction of soluble constituents from the rubber; c) A chemical reaction with the rubber. The amount of absorption a) is usually larger than that of extraction b), so that the net result is an increase in volume, commonly termed swelling. The absorption of liquid can profoundly alter physical and chemical properties and hence change tensile strength, extensibility and hardness of the rubber, so it is important to measure these properties after treatment of the rubber. The extraction of soluble constituents, especially plasticizers and anti-degradants, can likewise alter the rubber s physical properties and chemical resistance after drying (assuming the liquid to be volatile). Therefore, it is necessary to test these properties following immersion or drying of the rubber. This standard specifies the test methods necessary for determining the changes in the following properties: - Change in mass, volume, and dimensions; - Extractable matter; - Change in hardness and tensile stress-strain properties after immersion and after immersion and drying. Although in some respects these tests might simulate service conditions, no direct correction with service behavior is implied. Thus, the rubber giving the lowest change in volume is not necessarily the best one in service. The thickness of the rubber needs to be taken into account since the rate of penetration of liquid is time-dependent and the bulk of a very thick rubber product might remain unaffected for the whole of the projected service life, especially with viscous liquids. Moreover, it is known that the action of a liquid on rubber, especially at high temperature, can be affected by the presence of atmospheric oxygen. The tests described in this standard can, however, provide valuable information on the suitability of a rubber for use with a given liquid and, in particular, constitute a useful control when used for developing and studying the rubbers resistance to liquids. Page 6 of 28

5 Rubber, vulcanized or thermoplastic Determination of the effect of liquids WARNING: Personnel using this standard shall be familiar with normal laboratory practice. This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices AND to ensure compliance with any national regulatory conditions. 1 Scope This standard specifies the methods of evaluating the resistance of vulcanized and thermoplastic rubbers to the action of liquids by measurement of properties of the rubbers before and after immersion in test liquids. The liquids concerned include current service liquids, such as petroleum derivatives, organic solvents, and chemical reagents, etc. This standard applies to vulcanized rubber or thermoplastic rubber. 2 Normative references The following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) are applicable to this Standard. GB/T 262 Petroleum products and hydrocarbon solvents - Determination of aniline point and mixed aniline point (GB/T , ISO 2977:1997, MOD) GB/T 265 Petroleum products - Determination of kinematic viscosity and calculation of dynamic viscosity GB/T 267 Petroleum products - Determination of flash point and fire points - Open cup GB/T 388 Determination of sulfur content of petroleum products (oxygen bomb method) Page 8 of 28

6 GB/T 528 Rubber, vulcanized or thermoplastic - Determination of tensile stress-strain properties (GB/T , ISO 37:2005, IDT) GB/T 1884 Crude petroleum and liquid petroleum products - Laboratory determination of density - Hydrometer method (GB/T , eqv ISO 3675:1998) GB/T 2941 Rubber - General procedures for preparing and conditioning test pieces for physical test methods (GB/T , ISO 23529:2004, IDT) GB/T 3535 Petroleum products - Determination of pour point (GB/T , ISO 3016:1994, MOD) GB/T 3536 Petroleum products - Determination of flash and fire points - Cleveland open cup method (GB/T , ISO 2592:2000, MOD) GB/T 6031 Rubber, vulcanized or thermoplastic - Determination of hardness (10 ~ 100 IRHD) (GB/T , idt ISO 48:1994) GB/T Plastic - Method of test for determination of the effects of immersion in liquid chemicals (GB/T , ISO 175:1999, MOD) ISO 3104 Petroleum products - Transparent and opaque liquids - Determination of kinematic viscosity and calculation of dynamic viscosity ISO 5661 Petroleum products - Hydrocarbon liquids - Determination of refractive index 3 Test device 3.1 Total immersion device The design shall take into account the volatility of the test liquid and the immersion temperature to prevent and minimize evaporation of the test liquid and the ingress air. For tests at temperatures considerably below the boiling point of the test liquid, a stoppered glass vessel shall be used. For tests at temperatures near the boiling point of the test liquid, the vessel shall be fitted with a reflux condenser or other suitable means of minimizing the evaporation of liquid. The vessel shall be so dimensioned that the test pieces remain completely immersed and all surfaces are completely exposed to the liquid without any restriction. The volume of liquid shall be at least 15 times the combined volume Page 9 of 28

7 variations can have a large influence on the effect on rubber. Therefore, complete details of the composition of the fuel used shall be included in the test report. As commercial liquids do not always have a constant composition, a standard liquid consisting of well-defined chemical compounds or mixtures of compounds shall be used as reference liquid for the purpose of classification of vulcanized or thermoplastic rubbers or quality control. Some suitable liquids are listed in Appendix A. When testing to determine the effect of chemical solutions, the concentration of the solution shall be appropriate to the intended use. It shall ensure that the composition of the test liquid does not undergo excessive changes throughout the test. The ageing of the test liquid and any interaction with the test pieces shall be taken into account. If there are chemically active additives in the liquid, OR if there is a significant change in composition by extraction, absorption or reaction with the rubber, either the volume shall be increased OR the liquid shall be replaced with fresh liquid at specified intervals. 5 Test pieces 5.1 Preparation of test piece The test piece shall be prepared in accordance with the provisions of GB/T Dimensions The test piece thickness is 2.0 mm ± 0.2 mm. The test piece may also be cut from the product, AND if the thickness is less than 1.8 mm, the actual thickness of the test piece shall be used as the test thickness. If the test piece thickness is greater than 2.2 mm, the thickness shall be treated to 2.0 mm ± 0.2 mm. Test results for the test pieces of different thicknesses are not comparable. The sample used for the measurement of volume change and mass change is type I: 25 mm x 50 mm rectangle; type II: 25 mm x 25 mm square. Note: As for the test pieces of different specifications, the measured results cannot be compared. It is recommended to use type I samples first. The lateral dimension of the test piece for hardness change measurement is not less than 8 mm. Page 12 of 28

8 The test piece used for measuring dimensional change may be type I or type II, AND it may also select the round test piece of diameter 44.6 mm (Inner circle of the type A standard ring test piece in GB/T 528). The test piece used for measuring surface area change is a vertically cut parallelogram. This can be achieved by two consecutive cuts at approximately right angles to each other, with a cutter consisting of two parallel blades, suitably spaced. The length of the test piece sides shall be nominally 8 mm. Note: For the determination of the change in surface area, it might by convenient to use smaller or thinner test pieces, for example when cut from products OR fast detection test is required. However, the results might not be comparable with those obtained using the specified thickness. Smaller test pieces will reduce the precision of the results. Test pieces for the determination of tensile properties shall be in accordance with the provisions of GB/T 528. Type 2 dumb-bell like test pieces are preferred. AND this test piece may also be used for the determination of hardness change. For tests with liquid contact on one surface only, the test piece shall consist of a disc with a diameter of about 60 mm. 5.3 Time interval between vulcanization and testing Unless otherwise specified, the time interval between the vulcanization and test shall be as specified in GB/T 2941 as below. For all test purposes, the minimum time between vulcanization and testing shall be 16 h. For non-product tests, the maximum time interval between vulcanization and testing shall be 4 weeks AND, for evaluation intended to be comparable, the tests shall be carried out using, as far as possible, the same time interval. For product tests, whenever possible, the time interval between vulcanization and testing shall not exceed 3 months. In other cases, the tests shall be made within 2 months of the date of receipt of the product by the customer. 5.4 Test piece conditioning The test piece shall be conditioned for at least 3 hours at the standard laboratory temperature as specified in GB/T AND the same temperature shall be used throughout any test or any series of tests intended to be comparable. Page 13 of 28

9 USE 3 test pieces for each set of measurements and MAKE any identification marks required before immersion. IMMERSE the test piece in a device (3.1 or 3.2) containing the test liquid (4); PLACE the device a thermostatic chamber or a liquid heating thermostat which has reached the desired temperature (6.1). For full immersion tests, PLACE the test pieces at a distance of at least 5 mm from the sides of the vessel AND at least 10 mm from the bottom and top surfaces. If the density of the rubber is less than that of the liquid, means shall be provided for holding the test pieces completely below the surface of the liquid. The ingress of air shall be avoided. If the influence of air is to be tested, the degree of access of air shall be determined by agreement between the interested parties. After the soaking test, TAKE the test device out from the incubator or the liquid heating thermostat; CONDITION it at standard laboratory temperature for 30 min. Or otherwise quickly TRANSFER the test piece into a prepared new test liquid at this temperature and ALLOW it to stand for a period of 30 min. REMOVE surplus test liquid from the test piece surface. When volatile liquids are used, REMOVE and quickly WIPE the test pieces with a filter or a piece of lint-free fabric. Viscous non-volatile liquids can be removed by filter paper AND, if necessary, by quickly immersing the test pieces in a volatile liquid, such as methanol or petroleum ether, then quickly wiping them. And then PERFORM the performance tests. Following removal of the test pieces from volatile test liquids, it is important that each subsequent manipulation takes place as soon as possible. After wiping off the surface residual liquid from the test pieces, quickly PLACE the test pieces into the weighing bottles to determine the volume change and mass change of the rubber. After the determination, if the same test pieces are used for the measurement of other properties, IMMERSE the test piece in this volatile liquid again, with the immersion duration complying with the requirements of 6.2. AND the maximum time between removal from the test liquid and the completion of all properties determination shall be: - Change in dimensions: 1 min; - Change in hardness: 1 min; - Tensile test: 2 min. If the test is to be continued, quickly IMMERSE the test piece in the liquid again and RETURN them into the incubator or liquid temperature control device. Page 15 of 28

10 mi, liq - The mass of the immersed test piece in the newly prepared test liquid (with sinker), in grams (g); ms, liq - The mass of the sinker in the newly prepared test liquid, in grams (g). 7.4 Change in dimension At the standard laboratory temperature, MEASURE the test piece length (width) close to the centerline of the test piece, accurate to 0.5 mm; TAKE the mean value of the two measurement results at the upper surface and lower surface. USE the thickness gauge to measure the thicknesses at four different positions on the test piece; TAKE the mean value. The test pieces after immersion shall be carried out in accordance with the above provisions. USE the equation (5) to calculate the percentage change in length (ΔL100): Where: l0 - The initial length of the test piece, in millimeters (mm); li - The length of the test piece after immersion, in millimeters (mm). USE the same method to calculate the percentage change in width and the percentage change in thickness. REPORT the result as the median value for the three test pieces. The percentage change in surface area may also be calculated by determining the length change and width change. 7.5 Change in surface area At the standard laboratory temperature, MEASURE the length of the initial diagonal of the test piece, accurate to 0.01 mm. After immersion, MEASURE the diagonal length again as described above. If measured by an optical instrument, the test piece may not be removed from the liquid AND it can be measured directly through a suitable glass vessel. USE the equation (6) to calculate the percentage change in surface area (ΔA100): Page 18 of 28

11 USE the equation (9) to calculate the percentage change in tensile stress-strain properties (ΔX100): Where: X0 - The performance value of the test piece before immersion; Xi - The performance value of the test piece before immersion. 7.8 Testing with liquid on one surface only This test is applicable to relatively thin sheet materials, for example rubber diaphragms, which are exposed to liquid on one surface only during use. MEASURE the test piece thickness; WEIGH the mass of the test piece in the air (m0), accurate to 1 mg. PLACE the test piece into the device as shown in Figure 1; POUR the test liquid into the device, with the depth in about 15 mm; INSERT the plug (F). PLACE the device into a calibrated thermostatic chamber to the required test time; TAKE out the device; if necessary, ADJUST to the standard laboratory temperature. POUR out the test liquid; TAKE out the test piece; USE filter paper or lint-free fabric to wipe off the residual liquid from the test piece surface. Then at the standard laboratory temperature, WEIGH the test piece mass (mi), accurate to 1 mg; MEASURE the test piece thickness. If the test liquid is volatile at room temperature, the test piece shall be tested in 2 minutes after removal from the liquid. USE the equation (10) to calculate the mass change rate per unit area (Δma) in grams per square meter (g/m 2 ). Where: m0 - The initial mass of the test piece, in grams (g); mi - The mass of the test piece after immersion, in grams (g); A - The circular area of the test piece in contact with the test liquid, in square meters (m 2 ). Page 20 of 28

12 TAKE out the immersed test piece from the test liquid and USE 25 ml newly prepared same liquid to wash the test piece; COLLECT the washing liquid together with the test liquid into the same vessel. PLACE this vessel in a test chamber at an absolute atmospheric pressure of about 20 kpa AND at a temperature of about 40 C; EVAPORATE the liquid to constant weight. At the same time CONDUCT a blank test; TAKE the same test liquid at a volume equal to the total volume of the sample immersion test liquid and the sample washing test liquid; EVAPORATE it to constant weight at the same conditions. The amount of the extractable matter is the percentage of the difference between the mass of the remaining matter produced after drying the test liquid used to immerse test piece and to wash test piece to constant weight and the remaining matter produced after drying the blank test liquid to constant weight AND the initial mass of the test piece. 8 Test report The test report shall include the following information: a) This standard number; b) Test piece description 1) A detailed description of the test piece and its origin; 2) Detailed description of the material, including: vulcanization temperature, vulcanization time, and the time interval between vulcanization and testing; 3) Test piece preparation method: molding or cutting; 4) Test liquid description: If it is mineral oil (except for ASTM No.1, IRM902, IRM903, and domestic No.1, 2, 3 standard oil), it shall also include density, viscosity, refractive index, aniline point or aromatic hydrocarbon content (if necessary). c) Test and test method description 1) Method of use; 2) Test piece type; 3) The standard laboratory temperature used; Page 22 of 28

13 The 102 service liquid is intended to simulate certain high-pressure hydraulic oils. It is a mixture consisting of 95% (by mass fraction) of ASTM No.1 oil and 5% (by mass fraction) of a hydrocarbon-compound oil additive which contains 29.5% to 33% (by mass fraction) of sulfur, 1.5% to 2% (by mass fraction) of phosphorus, and 0.7% (by mass fraction) of nitrogen and other desired additives. A service liquid The 103 service liquid is intended to simulate phosphate-ester hydraulic oils (tri-n-butyl phosphate) used in aircraft. A.4 Chemical reagents The chemical reagents used shall be the same as the actual reagents used in the product. If not specified, the chemical reagents used shall comply with the provisions of GB/T Page 27 of 28