QB/T 2888-2007Polyurethane fascicular microfibre synthetic leather (English PDF)

5.3.3 Length

Use a measuring tool, which has an accuracy of 1 cm, to measure the length of each roll, accurate to 1 cm.

5.4 Appearance

Carry out visual inspection under natural light. The color difference shall be carried out, according to the provisions of GB/T 250-1995.

5.5 Determination of apparent density

5.5.1 Cut 3 pieces of specimen. Measure the thickness of 4 points, along the periphery of each piece. Take the average value, accurate to 0.01 mm.

5.5.2 Weigh the mass of the specimen, accurate to 0.1 mg.

5.5.3 The results are calculated according to formula (1). Take the arithmetic mean of the test results of three specimens, with an accuracy of 0.01 g/cm3.

Where:

rho - The apparent density, in grams per cubic centimeter (g/cm3);

m - The mass of specimen, in grams (g);

A - The area of specimen, in square millimeters (mm2);

b - The thickness of specimen, in millimeters (mm).

5.6 Tensile load and elongation at break

Make measurements, according to the provisions of QB/T 2710-2005. Test speed is (100 ± 10) mm/min. Record the maximum load during stretching. Take the arithmetic mean of the test results of three specimens, accurate to 1 N.

5.7 Tear load

5.7.1 The tensile testing machine shall meet the requirements of QB/T 2710-2005. Self- tightening clamps are available.

5.7.2 Test procedure: Cut 3 specimens of 100 mm x 5 mm along the longitudinal and lateral directions, respectively. Cut the specimen from the center of the short side of each specimen, along the direction parallel to the long side; the cut length is 70 mm.

Clamp the two cut ends on the tensile testing machine in opposite directions. Carry out the test, at a tensile speed of (100 ± 10) mm/min. Record the maximum load when the specimen is torn.

5.7.3 The test results are represented by the arithmetic mean of the test results of each group of specimens, accurate to 1 N.

5.8 Peeling load

The peeling load shall be tested, according to the provisions in 5.9 of GB/T 8949-1995.

The size of the specimen is 100 mm x 20 mm; the bonding length is 70 mm; the adhesive can be polyurethane resin; the specimen shall be firmly bonded; the drying temperature shall be such that the adhesive can be dried. The specimen is peeled off about 20 mm;

the speed of the stretching machine is (100 ± 10) mm/min.

5.9 Burst

The bursting test shall be carried out according to the provisions of QB/T 2712-2005.

When the specimen is placed, the surface layer is upward; the base layer is in contact with the steel ball. Record the load, when the specimen is stretched to a height of 7.0 mm.

5.10 Folding fastness

The folding fastness is tested, according to the provisions of QB/T 2714-2005. Cut two groups of specimens, along the lateral direction, each group has 2 pieces. The surface layer of the specimens is folded inward. The two groups of specimens are folded, for

200000 times at (23 ± 2) °C and 25000 times (-10 ± 1) °C, respectively. Then observe the changes of the outer and inner parts of the folded part.

5.11 Surface color fastness

5.11.1 Method

The test bench of the rubbing testing machine is a semi-circular plate, which has a radius of 20 cm. The rubbing element is a curved surface, which has a surface radius of 45 mm; the test load is 1.96 N; the reciprocating speed is 30 times/min; the number of rubbings is 100. It is respectively expressed in the lowest level of the test results of each group of specimens.

5.11.2 Dry rubbing

Cut 2 specimens of 220 mm x 25 mm. Conduct the test according to 5.11.1. Judge the grade according to GB/T 251-1995.

5.11.3 Wet rubbing

After immersing the white cotton cloth in distilled water for 10 minutes, the water content shall be carried out according to the provisions of GB/T 3920-1997; the test

P - Moisture permeability, in milligrams per square centimeter per hour (mg/cm2·h);

m0 - The mass of the first weighing cup and specimen, in milligrams (mg);

m1 - The mass of the second weighing cup and specimen, in milligrams (mg);

m2 - The mass of the third weighing cup and specimen, in milligrams (mg);

m3 - The mass of the fourth weighing cup and specimen, in milligrams (mg);

A - The moisture permeability area of the specimen, in square centimeters (cm2).

5.13 Water absorption

5.13.1 Water absorption shall be measured according to GB/T 4689.21-1996.

5.13.2 Calculate the water absorption, according to the formula (3). Take the arithmetic

mean of the test results of two test pieces. Keep the calculation results as integers.

Where:

Q - Water absorption, expressed in percentage (%);

V - The water absorption of the specimen after soaking for a specified time, in milliliters (mL);

d - The density of water, 1 gram per milliliter (1 g/mL);

m - The mass of the specimen before immersion, in grams (g).

5.14 Water resistance

Water resistance is tested, according to the provisions of GB/T 4744-1997. According to Table 11, cut two pieces of specimens of Phi60 mm. The surface layer of the specimen is immersed in water; the immersion surface is a circle of Phi50 mm. The water temperature is (20 ± 2) °C. Inject water at a speed of 10 mm/s. Stop water injection, when the water pressure reaches 14.7 kPa. Visually test whether there are water droplets on the upper surface of the specimen, after 1 min.

5.15 Heat-resistant adhesion

5.15.1 Test procedure

Superpose the surface layers of the two specimens together. Put them between two pieces of 60 mm x 60 mm x 3 mm glass. Then press the glass by a weight of 3 kg. Place it in an air blast incubator at (100 ± 2) °C. Take it out after 1 h. Remove the weight.

Place it at room temperature for 1 h. Then gently uncover the superposed specimens by hand.

5.15.2 Result judgment

Grade 5: No change in the surface layer;

Grade 4: Gloss and surface shape slightly changed;

Grade 3: Gloss and surface shape changes;

Grade 2: Damage to the surface layer;

Grade 1: Damage below the surface layer.

6.1 Group-batching

Products are inspected and accepted in units of batches. The products of not more than

10000 m, which are continuously manufactured using the same raw material, formula, process, form a batch.

6.2 Exit-factory inspection

The exit-factory inspection items are all items in Table 3, Table 4, Table 5, as well as the items 1, 2, 3, 4 in Table 6.

6.3 Type inspection

Type inspection items are all technical requirements in Chapter 4. In one of the following situations, type inspection shall also be carried out.

a) Appraisal of trial production of new products or old products after trans-plant production;

b) After formal production, when there are major changes in structure, raw materials, processes, which may affect product performance;

c) Every six months during normal production;

d) When the product resumes production half a year after the product has been discontinued;

e) When there is a large difference between the exit-factory inspection result and the previous type inspection;

f) When the national quality supervision agency requests type inspection.

7.1 Marking

Each roll of product packaging shall have the following signs:

a) The name and address of the manufacturer;

b) Product name and adopted standard number;

c) Product specifications (thickness, width, length, color, pattern, etc.);

d) Trademarks;

e) Inspector code;

f) Production date and production batch number;

g) Anti-pressure, moisture-proof and other marks.

7.2 Packaging

The inner packaging is soft-packed by plastic bags or foam cloth; the outer packaging is in the form of corrugated boxes, heat-shrinkable films or according to user requirements. Instructions for use shall be attached to the outer packaging. The instructions for use shall include usage, precautions for use, storage period, etc.

7.3 Transportation

During the transportation of the product, it shall be handled lightly; do not expose to the sun and rain; keep the packaging intact.

7.4 Storage

The product is stored in a well-ventilated warehouse, which shall be protected from moisture, extrusion, mildew, away from heat sources. The storage period of the product shall not exceed two years from the date of production.

Appendix A (Normative)

Hydrolysis resistance test

A.1 Test method 1 - Jungle weathering test

A.1.1 Test sample size

150 mm x 150 mm.

A.1.2 Test procedure

A.1.2.1 Hang the sample in a constant temperature and humidity device, for damp heat aging, at a constant temperature and humidity of (70 ± 2) °C and a relative humidity of

95% or more.

A.1.2.2 After damp heat treatment for 168 h ~ 528 h (the cycle time error is within ±2 h), take out the test piece. Place it for 2 h, at a temperature of (23 ± 2) °C and a relative humidity of 45% ~ 55%. Observe the surface changes. Test the peeling load or folding fastness of the specimen.

Note: The damp heat treatment time and hydrolysis resistance index are subject to agreement, between the supplier and the buyer.

A.2 Test method 2 - Alkali resistance test

A.2.1 Test sample size

100 mm x 20 mm.

A.2.2 Test procedure

Under the conditions of temperature (23 ± 2) °C and relative humidity of 45% ~ 55%, soak the specimen in 10%NaOH and leave it for 24 h. Dosage of test solution, soaking and rinsing and wiping shall comply with the provisions in 3.7.1, 3.7.2, 3.7.3 of GB/T

11547-1989. Take out the specimen and rinse it with water. Dry it completely in an oven at (102 ± 2) °C. Then observe the erosion and cracking on the surface of the test piece

OR the peeling load of the test sample.

......