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

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1 Translated English of Chinese Standard: GB/T GB NATIONAL STANDARD OF THE PEOPLE S REPUBLIC OF CHINA ICS G 17 GB/T Cellulose diacetate flake for industrial use 工业用二醋酸纤维素片 GB/T How to BUY & immediately GET a full-copy of this standard? Search --> Add to Cart --> Checkout (3-steps); 3. No action is required - Full-copy of this standard will be automatically & immediately delivered to your address in 0~60 minutes. 4. Support: Sales@ChineseStandard.net. Wayne, Sales manager Issued on: October 09, 2015 Implemented on: May 01, 2016 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 26

2 Table of Contents Foreword Scope Normative references Terms and definitions Classifications Requirements Test methods Inspection rules Marking, packaging, transportation and storage Shelf life... 9 Appendix A (Normative) Determination of acetyl value Appendix B (Normative) Determination of intrinsic viscosity Appendix C (Normative) Determination of moisture Appendix D (Normative) Determination of the plugging value Appendix E (Normative) Determination of free acid Appendix F (Normative) Determination of heat stability Appendix G (Normative) Determination of brightness L and color a and color b Page 2 of 26

3 Foreword This standard was drafted in accordance with the rules given GB/T This standard was proposed by the China Petrochemical Industry Federation. This standard shall be under the jurisdiction of the National Chemical Standardization Technical Committee (SAC/TC 63). The drafting organizations of this standard: Nantong Acetate Co., Ltd., China Chemical Economic and Technological Development Center, Ningbo Da an Chemical Industry Co., Ltd., Sichuan Pushi Acetate Co., Ltd. The main drafters of this standard: Yang Zhanping, Wei Jing, Yang Jianhai, Li Xiaodong, Huanghua, Xie Linjun, Shen Lin, Gao Chunhong, Si Youyin, Zhang Dejie, Yu Wenji, Yang Xiaobing. Page 3 of 26

4 Cellulose diacetate flake for industrial use 1 Scope This standard specifies the terms and definitions, categories, requirements, test methods, inspection rules, markings, packaging, transportation, storage and shelf life of cellulose diacetate flake for industrial use (abbreviated as diacetate flake). This standard applies to diacetate flake produced by the plant cellulose under the action of catalyst through such processes as acetylation. 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 601 Chemical reagent - Preparations of standard volumetric solutions GB/T 603 Chemical reagent - Preparations of reagent solutions for use in test methods GB/T 6678 General principles for sampling chemical products GB/T 6679 General rules for sampling solid chemical products GB/T 6682 Water for analytical laboratory use - Specification and test methods GB/T 8170 Rules of rounding off for numerical values & expression and judgement of limiting values 3 Terms and definitions The following terms and definitions apply to this document. 3.1 Acetyl value Page 4 of 26

5 GB/T An indicator characterizing the degree of acetylation of diacetate flake, expressed as the mass fraction of the acetyl (acetic acid) replacing the hydroxyl cellulose. Plugging value An indicator characterizing the filterability of diacetate flake pulp. Under specified conditions, it is calculated in accordance with the amount of filtration. Free acidity An indicator characterizing the free acid of diacetate flake, expressed as the mass fraction of the free acidity (by acetic acid) contained in the diacetate flake. Heat stability The stability of diacetate flake to heat. Under the specified high temperature conditions, the number of grains of the baked diacetate flake which change into black brown, AND free of black brown indicates that the heat stability of the diacetate flake is qualified. Brightness L The color brightness of the diacetate flake in the three-dimensional uniform color space color measurement system. The greater the brightness value, the more white the diacetate flake; AND the smaller the brightness value, the more dark the diacetate flake. Color a The red and green degree of the diacetate flake in the three-dimensional uniform color space color measurement system. The color a indicates reddish if it is positive, AND greenish if it is negative. Page 5 of 26

6 5.2.2 When the diacetate flakes are used in the manufacture of clothing tow, teeth and other skin or mouth contact products, they shall comply with the relevant industry practices. 6 Test methods Warning: Some test procedures and the acetone solution used in the test method may cause dangerous situations. The operator shall take appropriate safety and protective measures. 6.1 General provisions Unless otherwise specified, only water identified as analytical pure reagent and level III water or equivalent purity as specified in GB/T 6682 is used in the analysis. The standard solutions, reagents and products as required for analysis, unless otherwise specified, shall be prepared in accordance with the provisions of GB/T 601 and GB/T Sample Preparation At ambient temperature (23 ± 5) C and humidity relative humidity (60 ± 15) %, TAKE the laboratory sample of about 250 g; POUR it into a clean grinder (grinding speed shall not exceed 1000 r/min. If the grinder inside is not clean, after cleaning it, it is preferable to first place about 60 g of sample into the grinder to grinding it. TAKE out the ground sample and DISCARD it.) LET the thoroughly ground sample all pass the 20-mesh standard sieve to produce a powder with a particle size of less than 850 μm. Immediately CONTAIN the powder into the glass bottle; COVER the cap to seal it; PREPARE for analysis. 6.3 Determination of acetyl value MAKE determination in accordance with the provisions of Appendix A. 6.4 Determination of intrinsic viscosity MAKE determination in accordance with the provisions of Appendix B. 6.5 Determination of moisture MAKE determination in accordance with the provisions of Appendix C. 6.6 Determination of plugging value MAKE determination in accordance with the provisions of Appendix D. 6.7 Determination of free acidity Page 7 of 26

7 Appendix A (Normative) Determination of acetyl value A.1 Method summary Diacetate flakes has saponification reaction with excess alkali, AND then it is back titrated by sulfuric acid standard solution. AND the acetyl value is calculated in accordance with the sample and blank titration data. A.2 Reagents A.2.1 Acetone, chemically pure. A.2.2 Phenolphthalein indicator (1 g/l). A.2.3 Sulfuric acid standard titration solution, c (1/2H2SO4) = 1.0 mol/l. A.2.4 Sodium hydroxide standard solution, c (NaOH) = 1.0 mol/l. A.3 Instruments A.3.1 Analytical balance, with the sensitivity of 0.1 mg. A.3.2 Oven, accuracy of 1 C. A.3.3 Magnetic stirrer, 0 ~ 500 r/min. A.3.4 Weighing bottle, 50 mm 30 mm. A.3.5 Acid burette, 50 ml, the minimum scale value 0.1 ml. A.3.6 Alkali burette, 15 ml, the minimum scale value 0.1 ml. A.3.7 Conical flask, 500 ml (with ground plug). A.3.8 Dryer. A.4 Determination procedures A.4.1 USE the weighing bottle to weigh about 2.1 g of dry sample (accurate to 0.1 mg, and the drying method is as shown in Appendix C); TRANSFER it all into a conical flask. Page 10 of 26

8 A.4.2 USE 10 ml of water to rinse the bottle wall; ADD a magnetic stirrer; ADD 150 ml of acetone; PLUG it; PLACE it into a magnetic stirrer to stir it until it is completely dissolved. A.4.3 While stirring, USE an alkali burette to add ml of sodium hydroxide standard solution (dropping speed to not form floc is appropriate) into the conical flask; PLUG it; CONTINUE stirring for 30 min. A.4.4 Along the conical flask wall, ADD 100 ml of water at about 80 C; STIR it for another 15 min; ADD 4 ~ 5 drops of phenolphthalein indicator. A.4.5 While stirring, USE the sulfuric acid standard titration solution for titration until the solution is colorless; CONTINUE stirring for 2 min; AND it shall be considered as end point if there is no color change. RECORD the consumed sulfuric acid standard titration solution v1 (accurate to 0.01 ml). A.4.6 MEASURE 150 ml of acetone and 10 ml of water; PLACE it into the conical flask; PLUG it. PLACE the conical flask on the magnetic stirrer to stir it; REPEAT the procedures A.4.3 ~ A.4.5 to perform blank test. RECORD the consumed sulfuric acid standard titration solution v2 (accurate to 0.01 ml). A.4.7 MAKE burette volume correction and temperature volume correction for v1 and v2 to obtain V1 and V2. A.5 Result calculation The mass fraction of acetyl value J, expressed in percentage (%), is calculated in accordance with the formula (A.1): Where: V1 - Volume of the sulfuric acid standard titration solution consumed by the sample after calibration, in milliliters (ml); V2 - Volume of the sulfuric acid standard titration solution consumed by the blank after calibration, in milliliters (ml); c - Sulfuric acid standard titration solution concentration, in moles per liter (mol/l); M - Molar mass of acetic acid, in grams per mole (g/mol) (M = g/mol); Volume unit conversion factor; m - Dry sample mass, in grams (g). Page 11 of 26

9 Appendix C (Normative) Determination of moisture C.1 Method summary At a certain temperature, the diacetate flakes are dried in oven, AND the moisture is calculated in accordance with the ratio of the mass difference of the diacetate flake before and after drying to the original mass. C.2 Instruments C.2.1 Analytical balance, sensitivity of 0.1 mg. C.2.2 Oven, accuracy of 1 C. C.2.3 Dryer. C.2.4 Weighing bottle, 50 mm 30 mm. C.3 Determination procedures C.3.1 WEIGH about 5 g (accurate to 0.1 mg) of sample; PLACE it into a weighing bottle which had been dried to constant weight; PLACE it into the oven; OPEN the bottle cap; DRY it at (105 ± 3) C for 2 h. C.3.2 CAP the bottle; TRANSFER it into the drier; COOL it for 30 min; WEIGH it, accurate to 0.1 mg. C.4 Result calculation Moisture mass fraction W, expressed in percentage (%), is calculated in accordance with formula (C.1): Where: m1 - Mass of the weighing bottle with cap before being dried, in grams (g); m2 - Mass of the weighing bottle with cap and sample before being dried, in grams (g); Page 16 of 26

10 Appendix F (Normative) Determination of heat stability F.1 Method summary The diacetate flake is baked at high temperature, AND its heat stability is characterized by the color change. F.2 Instruments F.2.1 Culture dishes, d80 mm 30 mm. Quartz glass. F.2.2 Oven, accuracy of 1 C. F.3 Determination procedures F.3.1 CONTROL the oven temperature at (210 ± 2) C; ADD the sample into the culture dish to about 15 mm. PLACE the culture dish in the oven; F.3.2 After closing, the oven temperature shall reach the control temperature within 3 min; BAKE it for 10 min. F.3.3 TAKE out the culture dish; PERFORM visual observation. F.4 Result presentation If the sample has no dark brown or black particles, it represents that the heat stability is qualified. If the sample has dark brown or black particles, it represents that the heat stability is disqualified. Page 23 of 26

11 Appendix G (Normative) Determination of brightness L and color a and color b G.1 Method summary USE a standard whiteboard to calibrate the three-dimensional uniform color space colorimeter (referred to as a colorimeter), then USE the colorimeter to detect the tristimulus values X, Y, Z of the diacetate flakes, and CALCULATE the color coordinates of the diacetate flakes in the Hunter anti-coordinate system (color brightness, red and green degree, blue and yellow degree). G.2 Instruments G.2.1 Colorimeter, measuring window diameter: 20 mm ~ 25 mm, lighting observation conditions: d/0, lighting and field of view: D65/10. G.2.2 Die-cutting machine, including hydraulic press and mold body. The hydraulic press load is greater than 25 t; the mold is composed of the base, the mold and the upper pressing block, the material is stainless steel, mold inner diameter is 6.75 cm, AND the prepared mold piece thickness is about 0.5 cm. G.2.3 Analytical balance, sensitivity of 0.1 g. G.3 Mold piece preparation WEIGH (15.0 ± 0.1) g of sample on the analytical balance. INSTALL the mold on the base; POUR the sample into the mold and FLATTEN it; PLACE the upper pressing block into the mold; PLACE the assembled mold body under the hydraulic press and APPLY load, until reaching to the pressure of 25 t; MAINTAIN it for 2 min; RELEASE the pressure; TAKE off the mold piece; MARK the edge of the mold piece; USE the contact surface of the mold piece with the mold body base as the test surface; after marking, PLACE the mold piece in a clean plastic bag to prepare for test (the mold piece shall be preserved in dark if it is not tested within 5 h). G.4 Determination procedures G.4.1 In accordance with the instructions of the instrument, TURN on the machine to preheat it; USE standard whiteboard to calibrate the colorimeter. Page 24 of 26