Black MDPE sheath (MH) instructions

2023-07-25

Product introduction: The black medium density polyethylene sheath material (MH) produced by the company is processed by advanced technology with high-quality polyethylene resin, carbon black masterbatch and other processing aids and functional additives. Mainly used in communication cables, optical cables, submarine cables, power cables, the maximum working temperature is 90 °C. This product has good processing and extrusion performance, which can meet the customer's high-speed extrusion at the same time, but also ensure the smooth and bright surface of the extruded cable, and completely solve the defect of surface melt crack / sharkskin shape of linear polyethylene during processing. This product is of high quality in the industry in terms of technical indicators and processing performance.

Executive standard: This product meets the requirements of GB/T15065-2009 standard.

Processing technology: It is recommended to use L/D=25:1 extruder production, refer to the extrusion temperature as shown in the following table

Warm zone	Mouth mold	Head	Neck	Zone 6	Zone 5	Zone 4	Zone 3	Zone 2	Zone 1
Setpoint	235	230	225	220	195	185	175	165	160

Product quality indicators:

Number	Indicator items		Standard value	Measured value
1	Melt flow mass rate, g/10min		≤2.0	1.5
2	Density, g/cm³		0.940～0.955	0.946
3	Tensile strength, MPa		≥17.0	18.2
4	Elongation at break, %		≥600	710
5	Low temperature impact embrittlement temperature, -76℃		Pass	Pass
6	Resistant to environmental stress cracking F₀，h		≥500	Pass
7	200℃ oxidation induction period, min		≥30	42
8	Carbon black content,%		2.60±0.25	2.62
9	Carbon black dispersion, grade		≤3	2.7
10	Vicat softening point, ℃		≥110	115
11	Thermal aging of air ovens	Tensile strength, MPa	≥16.0	17.6
11	Thermal aging of air ovens	Elongation at break, %	≥500	682
12	Dielectric strength Ed, kV/mm		≥25	30
13	Volume resistivity ρ_V，Ω·mm		≥1×10¹⁴	3.6×10¹⁴
14	Dielectric constant ε_r，		≤2.75	2.65
15	Dielectric loss factor tanδ		≤0.005	0.003