GB/T 37881-2019Plastics-Long glass fiber reinforced polypropylene (PP) compound for automotive (English PDF)

3.1 Long Glass Fiber Reinforced Polypropylene Compound

Long glass fiber reinforced polypropylene compound refers to glass fiber reinforced polypropylene granules and mixture with polypropylene resin, which is prepared by taking polypropylene as the matrix, adding continuous glass fiber and other additives, and adopting extrusion traction process. In the granules, the average length of glass fiber shall be not less than 6 mm.

3.2 Tensile Strength Retention

Tensile strength retention refers to the ratio of tensile strength after the aging of sample to tensile strength before the aging of sample, expressed in “%”.

3.3 Izod Notched Impact Strength Retention

Izod notched impact strength retention refers to the ratio of Izod notched impact strength after the aging of sample to Izod notched impact strength before the aging of sample, expressed in “%”.

4.1 General Rules

Long glass fiber reinforced polypropylene (PP) compound for automotive shall comply

6.1.2 In accordance with different requirements, respectively prepare the following

samples:

a) In accordance with Type-A mold in GB/T 17037.1-2019, prepare samples that comply with Type-1A in GB/T 1040.2-2006;

b) In accordance with Type-B mold in GB/T 17037.1-2019, prepare 80 mm x 10 mm x 4 mm samples;

c) In accordance with the requirements in 4.3.1 in GB 8410-2006, prepare 356 mm x 100 mm x 3 mm samples.

6.2 State Conditioning of Sample and Standard Environment of Test

6.2.1 Unless it is otherwise stipulated, state conditioning of sample shall comply with the stipulations in GB/T 2918-2018. In state conditioning, the temperature shall be

23 °C ± 2 °C; relative humidity shall be 50% ± 10%; time shall be not less than 40 h and not more than 96 h.

6.2.2 Tests shall be conducted under the standard environment stipulated in GB/T

2918-2018. Ambient temperature shall be 23 °C ± 2 °C; relative humidity shall be 50%

± 10%.

6.3 Appearance

Appearance test shall be conducted in accordance with the stipulations in SH/T 1541-

2006.

6.4 Ash Content

Ash content test shall be conducted in accordance with the stipulations in GB/T 9345.1-

2008. Adopt direct calcination method (Method-A); burning temperature shall be

750 °C ± 50 °C.

6.5 Tensile Strength

Tensile strength test shall be conducted in accordance with the stipulations in GB/T

1040.2-2006. Adopt Type-1A samples. Test rate shall be 5 mm/min.

6.6 Bending Strength and Bending Modulus

The test of bending strength and bending modulus shall be conducted in accordance with the stipulations in GB/T 9341-2008. Test rate shall be 2 mm/min.

6.7 Izod Notched Impact Strength

The test of Izod notched impact strength shall comply with the stipulations in GB/T

1843-2008. Specifically speaking:

Exit-factory inspection shall at least include granule appearance, ash content, tensile strength, bending strength, bending modulus and Izod notched impact strength retention.

7.3 Group Batch Rules and Sampling Plan

7.3.1 Group batch rules

A group batch shall be constituted of products which have the same designation, and are produced through the same line of production, the same raw materials and the same production process. Manufacturers may also build a group batch of products in accordance with a certain production cycle or storage bin.

7.3.2 Sampling plan

Samples may be taken among products that are already packed. Or, a specific sampling plan may be determined in accordance with the practical situation, for example, the production cycle.

The sampling of products that are already packed shall comply with the stipulations in

GB/T 2547-2008.

7.4 Determination Rules and Re-inspection Rules

7.4.1 Determination rules

The test result shall adopt round-off comparison method and comply with the stipulations in GB/T 8170-2008.

Products shall be inspected by manufacturer’s quality inspection department in accordance with the test methods stipulated in this Standard. In accordance with the inspection result and the requirements in this Standard, product quality shall be determined, and a certificate shall be proposed.

When products exit factory, each batch of products shall be attached with a product quality inspection certificate, which shall indicate product name, designation, batch No., and implemented standard.

7.4.2 Re-inspection rules

In the inspection result, when a certain indicator does not comply with the requirements in this Standard, re-take samples and conduct a re-inspection of the item in accordance with GB/T 2547-2008. The re-inspection result shall be a basis for quality determination of this batch of products.