PVC Resin for Pipes: Grades, Figures and What to Send
Pressure pipe, drainage, electrical conduit and fittings are the most common end products leaving this warehouse, and they run almost entirely on SG-5. This page covers three things: which grade fits which pipe, what the GB/T 5761-2018 figures decide on a pipe line, and what an enquiry needs. The figures are standard ranges; for any specific lot, the COA is the document that carries the measured numbers.
Which grade for which pipe
Water pressure pipe, drainage, electrical conduit and fittings all sit in this band. The chains are long enough for the long-term hydrostatic strength a pressure pipe is rated on, with enough flow to hold production speed on a normal twin-screw line. When a mill says "PVC resin", this is usually the grade it means.
Higher flow than SG-5, which suits rigid sheet, panels and part of the profile range. In pipe plants it covers companion sheet parts rather than the pressure pipe itself.
The lowest K value of the four and the best flow: injection-moulded fittings and rigid sheet. Load-bearing sections still run on SG-5.
The highest polymerisation and the lowest flow of the four: films, artificial leather and cable compound. Pipe is not what it is bought for.
The SG-5 grade page carries the full data sheet and FAQ; all four grades sit side by side on the specifications page; the full application map is on the applications page; packing formats and export documents are on the packing page.
What the K value decides on a pipe line
The SG-5 viscosity band is 107-118 mL/g, which is the same property expressed as a K value of 66-68. A resin at 107 and a resin at 118 are both "SG-5", but they are not the same material in an extruder: the lower end fuses faster and gives a wider processing window; the upper end carries longer chains, more strength and better long-term hydrostatic performance, and asks more of torque and stabiliser.
Pressure pipe is rated on long-term hydrostatic strength, and mills usually validate a formulation in the upper half of the band. If a formulation was validated on a resin near 112, a delivery at 107 will run, but weld strength and reject rate will not match the validation run. The position in the band belongs in the enquiry; it is the one thing that changes which lot is offered.
About choosing a grade for pipe
Which grade for pressure pipe?
SG-5, K 66-68 per GB/T 5761-2018. What moves long-term hydrostatic performance is the position inside the band, and mills usually validate in the upper half; write that position into the enquiry and the offered lot follows it.
Can SG-5 be used for drainage and conduit?
Yes. Drainage and conduit carry less pressure than a pressure pipe, and the same SG-5 band covers them. The difference sits in the formulation and the wall thickness more than in the resin grade.
Are the figures on this page measured values?
No. They are the standard GB/T 5761-2018 ranges, used to choose a grade. The measured values for a shipment are on its COA, which comes from the producing plant; we do not issue reports on the producer's behalf.
Enquire against the pipe line
The pipe type, the position in the K-value band, the quantity and the discharge port produce a dated FOB offer and the COA for the lot being offered.