HG/T 2821-1996 Dipped polyester cords for V-belts and multi-ribbed belts
Some standard content:
HG/T 2821-1996
The superior and qualified products of this standard are formulated by adopting the technical requirements of companies in two advanced foreign countries. The main technical indicators and test methods are the same as those of the requirements, but the writing rules are different. Some test methods and rubber compound formulas in the appendix are formulated according to the current domestic situation.
Appendix A, Appendix B, Appendix C, Appendix D and Appendix E of this standard are all appendices of the standard. This standard is proposed by the Technical Supervision Department of the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of Qingdao Rubber Industry Research Institute. The drafting units of this standard are: Qingdao Rubber Industry Research Institute, Wujiang Fuda Industrial Cord Co., Ltd., Qingdao Xinfei Rubber Factory, Jiangsu Taicang Rubber Skeleton Factory,
The main drafters of this standard are: Li Jian, Han Deshen, Hui Kangnan, Li Konghong, Wang Guangjian, 67
1 Scope
Chemical Industry Standard of the People's Republic of China
Dipped Polyester Cord for V-Belts and Multi-V Belts
HG/T2821 +—1996
This standard specifies the product classification, requirements, test methods, inspection rules and marking, packaging and storage rules of dipped polyester cords (referred to as polyester cords) for V-belts and multi-V belt cores. This standard is applicable to dipped polyester cords used as core materials for V-belts and multi-V belt products such as automotive belts, narrow V-belts, wide V-belts:
2 Classification
2.1 Type
The dipped polyester cords for V-belts and multi-mode belts are divided into the following two types: Hard ester cords: used for cut-type V-belts. Multi-V belt, a)
Soft polyester cord: hand-wrapped cloth belt
2.2 models
According to the fineness of the cord fiber and the cord structure, it is divided into eight models: diex1100×2×3, dtex1100×2×5, dtex1100×3×3dtex 1100x 4× 3, dtex 1100× 3× 5, dtex 1100 × 6 × 3, dtex 1100× 9x 3, and dtex 1100× 12× 3.
2.3 Marking
The specification marking content and order of polyester cord are soft and hard cord code, fineness code, cord structure, and standard number. The marking example is as follows:
dtex 1 100 × 6 × 3 ××××××F
Standard number
Cord structure, indicating that the number of initial strands is 6 and the number of strands is 3. Fineness code, indicating that the soft cord code is produced with 1100dtex raw yarn (the hard cord code is S) 3 Requirements
3.1 Materials and structure
Polyester cord is made of polyester filaments, corded into ropes, surface dipped in glue, and heat treated to shape. The finished product should be rolled into a drum. The fineness should be uniform.
3.2 Size
The diameter of the polyester cord should comply with the provisions of Table 1. dtex 1 100 × 2 × 3
dtex 1 100 × 3 × 3
dtex 1 100 × 2 × 5
dtex 1 100 × 3 × 4
dtex 1 100 × 3 × 5
dtex 1 100 × 6 × 3
dtex 1 100 × 9 × 3
dtex 1 100 × 12 × 3
33Physical and mechanical properties
HG/T 2821 —1996
Diameter of soft cord
1. 00 ± 0. 10
1.15±0.10
1.25±0.10
1.35±0.10
1. 50 ± 0. 10
1.65±0.10
2. 10± 0. 10
2. 40±0. 10
3.3.1 The physical and mechanical properties of high-quality soft polycool cords shall conform to the requirements of Table 2. Table 2
Breaking strength. N
Elongation at break, %
Elongation at 200N fixed load, %
Elongation at 300N fixed load, %
Elongation at 500N fixed load, %
Mass at fixed length, denominator/100m
Dry heat shrinkage (150C×3mi), %
Adhesion strength, N/cm
Diameter of hard cord
0.95±0.10
1. 15 ±0. 10
1. 22 ± 0. 10
1. 30± 0. t0
1. 62 ±0. [0
11.3±1.511.7±1.511.0±2.011.0±1.51.0±2.011.0±2.012.0±2.013.0±2.04. 0±0.7
28±05
74± 3. 0
3. 5± 0. 5||t t||110±4. 0
3.3±0, 5
3.3±0.822±0.8
145± 5.0 | 3±0. 5
332 The physical and mechanical properties of high-quality hard polyester cords shall conform to the requirements of Table 3, 70
2. 9±0. 5
2 3±0. 5
Breaking strength, N
Elongation at break%
100 N fixed load elongation. %
250N fixed load elongation. %
400N fixed load elongation, %
Fixed length mass, g/100m
Dry heat shrinkage (150c×3min), %
Adhesion strength. N/cm
HG/ T 2821—1996
1.3± 0.8
74.0±4.0
3.33 The physical and mechanical properties of qualified soft polyester cords shall conform to the requirements of Table 4. Table 4
Breaking strength, N
Elongation at break, %
178N Elongation at fixed load, %
198N Elongation at fixed load, %
296 N Elongation at fixed load, %
395 N Elongation at fixed load. %
494N Elongation at fixed load, %
Dry heat recovery (150c×30min), %
Adhesion strength, N/cm
t0. 9± 2. 0
3. 0±0. 7
11.6±1. 5
3. 0± 0.5
3. 0±0.#
122±20
334The physical and mechanical properties of qualified hard polyester cords shall conform to the requirements of Table 5. 瑰
110.0±4.0
12 8± 1. 5
4. 0± 0.5
30±07
13. 0± 1. 5
3. 5±0. 5
3.0±0. 7
11.0±1.5
196.0±4.0
13. 6± 1.5
12 8±1. 5
Break strength, N
Elongation at break, %
17NElongation at fixed load, %
198NElongation at fixed load, %www.bzxz.net
296NElongation at fixed load, %
395NElongation at fixed load %
Dry heat shrinkage increase (150C ×30 mm), %Adhesion strength, N/ cm
34Appearance quality
HG / T 2821 —1996
9. 1±1. 3
9. B± 1. 5
2.9±0. 5
4.5±0. 5
9.8± 1.5
3.7± 0. 5
34.1 The polyester cord should be free of defects such as bends, backlash, extra (few) strands, oversized joints, loose joints, and back strands that may hinder its use. 34.2 The adhesive of the polyester cord should be evenly connected and free of impurities, lack of adhesive, etc. 34.3 The winding of polyester cord drum should be flat and of appropriate tightness. The size of the cord should be suitable for V-belt molding. 4 Sampling
41 The appearance quality of polyester cord should be visually inspected according to the provisions of 3.4 of this standard. 6×3
9.2± 1. 5
4. 0± 0.5
4.3± 0.5
4.2 The size and physical and mechanical properties of polyester cord shall be inspected by batch sampling. The same batch of polyester cords with the same specifications and not more than 1000kg produced in the same dipping and heat treatment with the same batch of raw materials shall be considered as a batch. When the monthly output is less than 1000kg, at least one inspection shall be carried out every month. 43 Five cords shall be drawn from each batch of polyester cords as inspection samples and packed in black vinyl film bags (to prevent light exposure) for inspection. After packing, they are only allowed to be taken out of the bag for a short time during inspection. 44 Gloves must be worn when sampling and preparing samples, and the cords shall be prevented from untwisting. 4.5 Before testing the performance of the cord samples, they must be conditioned for at least 2 hours at a temperature of 23±2℃ and a relative humidity of 60% to 75%.
46 When the basic test results are unqualified, double the number of samples should be taken from the batch of cords to test the unqualified items. If one of the re-inspection items still fails, the batch of products is unqualified. 5 Test methods
51 Diameter of polyester cord: use a platen diameter measuring instrument to measure according to Appendix A. 52 Fixed length quality of polyester cord: use a length measuring device and an analytical balance to test according to Appendix B. 53 Breaking strength and breaking elongation of polyester cord: use a tensile testing machine to test according to Appendix ℃. 5 4 Dry heat shrinkage of polyester cord: use a dry heat shrinkage tester or an automatic constant temperature oven to test according to Appendix D. 55 Adhesive strength of polyester cord: use a vulcanizer, a thickness gauge and a tensile testing machine to test according to Appendix E. 72
6 Marking, labeling, packaging, storage and transportation
61 Marking
HG/ T 2821 - 1996
The outer packaging box must have obvious signs, which should include the following:) Product name:
Product specification mark;
Manufacturing unit:
Trademark;
Date of production.
62 Label
The following items should be stated on the label:
Product name;
Specification mark;
Number of cords in the box;
Manufacturing unit:
Date of production;
Precautions for use and storage,
According to the length, diameter, quantity, volume and quality of the polyester cord, appropriate packaging materials should be used for outer packaging. The inner packaging must be a black polyvinyl chloride bag. The packaging box should be accompanied by a label and a certificate of conformity. 64 Storage and Transportation
64.1 During storage and transportation, polyester cords should be kept away from direct sunlight and should not come into contact with acids, oils or harmful solvents. 6.4.2 During storage, the warehouse humidity should be maintained at 20±500 million and the relative humidity should be maintained at 60% to 70%. The storage period should not exceed six months from the date of production.
64.3 During storage, the polyester cord should be kept at least 1 meter away from heat sources and should not be deformed due to excessive pressure or bends. It is best to place the polyester cord upright in the packaging box and then place the packaging box on the shelf. Appendix A (Appendix to the standard)
A1 Measuring device
Method for measuring the diameter of polyester cord
The diameter of polyester cord is measured by a platen diameter measuring instrument with a measuring range of 0.01 to 10 mm. The diameter of the upper platen is 25.22 mm, the drop height is 4 m, and it should be able to apply a pressure of 1.7 N to the cord sample. A2 Specimen
Take one specimen with a length of more than 0.5 m from each of the five polyester cord samples, for a total of 5 specimens. A3 Test procedure
Measure the diameter of each specimen at two locations more than 100 mm apart in the following manner. Adjust the pointer of the diameter measuring instrument to indicate zero, place the cord flat on the lower platen of the measuring instrument, and then slowly drop the upper platen from a height of about 4 m. Read the value after the pointer is still, rotate the cord 90 degrees at the same location and measure again. Keep each measured value until the smallest value is reached. The second digit after the dot
A4 Expression of test results
Record the 20 measured values and their arithmetic mean, 4
Appendix B (Standard Appendix)
B1 Measuring device
Measuring method of fixed length quality of polyaldehyde wire
Use the fixed tension length measuring device and analytical balance shown in Figure B1 for measurement, E
1—Pulley; 2—Slider; 3—Wire rope screw; 4—Frame 5—Drum measuring wire: 6—Handwheel (for slider lifting); 1 yard (tensioning force) Figure B1 Schematic diagram of fixed tension length measuring device
B2 Test specimen
From five simple polyaldehyde wire rope samples, cut one specimen with a length of more than 2m, a total of 5 specimens, B3 Test procedure
B3.1 Clamp the specimen in the slider, use the base weight to apply tension to the specimen, and the magnitude of the tension is calculated according to formula (B1): F- 0.05 x f.
Where: F tension, cN;
f cord fiber fineness, dtcx
V-total number of cord fibers,
B3.2 After the cord is tightened, cut the cord at the mark below the length meter, lower the movable sliding block and cut the cord at the mark above the length meter, prepare 5 2m samples according to the above procedure, B3.3 Weigh the 5 samples separately and record the values. Each measured value is retained to one decimal place. B4 Expression of test results
Calculate the fixed length mass according to formula (B2):
Gro = G, × 50
Wherein: G10o--fixed length mass, g/100m; G—measured value in B3.3, g/2m,
Record the 5 measured fixed length mass values and their arithmetic mean, (B2)
Appendix C (Standard Appendix)
C1 Measuring device
Method for measuring breaking strength and elongation of polyester thread
Use a tensile testing machine and a test tool with suitable measuring range, C2 Test
From five simple polyester cord samples: take 2 cord specimens of each length that can ensure the clamping length between the two clamps is 802mm (800mm for hard cord), a total of 10 specimens: apply the pretension calculated according to formula (C1) and make marks at both ends of the clamping length.
-center. 05 × f
Where: F-
-pretension. cN
-cord fiber fineness: dtex;
total number of cord fibers,
C3 Test procedure
C3.1 Adjust the moving speed of the testing machine to 200mmmin. Adjust the pointer of the testing machine to make its indication value zero, (c1)
C3.2 Clamp the cord sample along the arc of the clamp. In the lower clamp, the clamping length is the marked spacing. When using the pneumatic clamp, the pressure on the barometer should be controlled at 0.5~0.62 MPa. C3.3 If an electronic tensile testing machine is used, the automatic test can be started after setting the load value of the fixed load elongation. If a testing machine that cannot automatically record the test results is used, the test shall be carried out in the following manner: Install recording paper on the testing machine, and place the drawing pin at the zero point of the recording paper and start the test. At the same time, the tension-strain curve shown in Figure C1 is automatically drawn until the rope breaks. Tension N
Number of breaking points
Strain%,
Figure C 1 Tension-strain
C3.4 If the rope breaks near the clamp (within 10mm), the test shall be repeated: and this phenomenon shall be recorded in the original record of the inspection report. This value should not be taken into account when calculating the average. C4 Expression of test results
According to the tension-strain curve, record: the measured values of breaking strength, breaking elongation and negative elongation of 10 specimens and their arithmetic mean, with the significant figures rounded to one decimal place. 76
Appendix D (Appendix to the standard)
Measurement method of thermal shrinkage of polyester cord
D 1 Measuring device
Measurement is carried out using a dry heat shrinkage tester or an automatic constant temperature oven and auxiliary tools. D2 Specimens
From the five-tube polyester cord samples, two specimens with a length of more than 400 mm are taken from each of them, for a total of 10 specimens. D 3 Test procedure
D3.1 Dry heat shrinkage tester method
When using a dry heat shrinkage tester for testing, the test is carried out according to the following procedure: D3.1.1 Open the instrument at least 30 minutes before the test. Adjust the test temperature to 150±1C and the heating time to 3min (30min for qualified products),
D3.1.2 Clamp one end of the sample in the fixture on the bracket, and apply tension calculated by formula (D1) to the other end of the sample, F - 0.02 × f-n
Wherein: F--pretension, cN;
-cord fiber fineness, dtex;
-total number of fibers in a cord,
D3.1.3 Adjust the pointer on the instrument to zero, and place the bracket with the sample into the heating box. When it is pushed into place, the heating switch and timer will be automatically started, and the heating will automatically stop after the set time is reached. Read the shrinkage rate (%) at this time. D3.2 Automatic constant temperature oven method
When using an automatic constant temperature oven and auxiliary tools for the test, the test shall be carried out according to the following procedures. D3.2.1 Clamp one end of the sample into a fixture with a length mark, and apply pre-tension to the other end according to D3.1, and mark it 200mm away from the clamp.
D3.2.2 Put the sample into a drying oven at 150±3℃ and heat it at a constant temperature for 3min (30min for qualified products) while keeping the pre-tension unchanged.
D3.2.3 While continuing to heat, measure the length L of the sample. The cord should not be untwisted during the entire test process. D4 Expression of test results
D4.1 When using a dry heat shrinkage tester, the dry heat shrinkage of 10 samples and their arithmetic mean can be directly read out. D4.2 When using a dynamic constant temperature drying oven, first calculate the dry heat shrinkage of 10 specimens according to formula (D2): S-
Where: S—dry heat shrinkage, %;
200 L
—length of the measuring plate after the specimen is heated, mm.
Calculate the arithmetic mean of the dry heat shrinkage of 10 samples, D4.3 The effective figures in the calculation are all taken to one decimal place, ×100
Appendix E (Standard Appendix)
E1 Test equipment
Polyester cord bond strength measurement method (T extraction method) The test equipment includes a flat plate sulfidation machine, a tensile testing machine and a thickness tester, E2 Specimens
From the five-simple polyester cord samples, 4 specimens with a length of more than 1m are cut, a total of 20 specimens, E 3 Test procedure
E3.1 Prepare the mixed rubber according to the formula 1 (see Table E1) or formula 2 (see Table E2) for the cord bond strength test. The two formulas are selected according to the use of the cord. After mixing, the rubber compound is left for 4 hours and then re-mixed before use. The rubber compound stored for 24 hours must be re-refined before use. The re-refining roller temperature should be 30~60℃. Table E1 Formula 1 for cord bonding strength test
No. 20 natural raw rubber
Styrene-butadiene rubber SBR 1 500
Zinc oxide
Stearic acid
Vulcanization accelerator DM
Vegetarian accelerator TMTD
Precipitation hydrated diammonium silicon
N762 carbon black
N330 carbon black
Pine tar
Adhesive A
Adhesive RS
Table E2 Formula 2 for cord bonding strength test
Hydrogen-butadiene rubber CR1212
Titanium diene rubber BR 9 000
Light magnesium oxide
Stearic acid
N 762 Light black
N330 Carbon black
Precipitated hydrated silica
Binder A
Binder RS
Zinc oxide
E3. 2 Use scissors to cut the rubber into strips according to the mold's height. The required number of strips is just enough to make the total height reach 11±0.5m. Use a thickness tester to check whether the strips meet the above requirements. E3.3 Fill half of the strips into the lower mold, put the wire rope sample with a tension of 2.0±0.2N into the groove in the mold, and then fill the remaining strips into the upper mold. E3.4 Put the mold into the preheated flat vulcanizer for vulcanization. For formula 1, the vulcanization condition is (143±1)C×30min; for formula 2, the vulcanization condition is (151±1)c×30min. E3.5 After vulcanization, cool the mold, take out the bonded sample in the mold, and place it under the laboratory conditions described in 4.6 for more than 2 hours, and then process it into the specified T shape (see Figure E1). The excess rubber around the cord should be cut off. Then, use a thickness tester to measure the thickness d of the rubber block in the direction where the cord is pulled out. The thickness of the rubber block is about 10 μm, and the test value is accurate to one decimal place. 79
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