In plastic and rubber industry various additives like stabilizer, modifiers, dyes etc are added to the primary resin or rubber, a process called compounding. These additives generally aid in processing of the polymer and improve the quality of the finished products. For example, polyvinyl chloride based products (PVC) require plasticizer to make it flexible, stabilizers to improve the heat stability and colorants/dyes to enhance visual appeal of the finished product. Thus, compounding/formulation plays a vital role in polymer and rubber industries.
The amount of these additives to be added are expressed in parts per hundred resin/rubber (PHR). PHR provides the quantity of additives per 100 units of base polymer. Let’s understand it with the following example. If a stabilizer is added to PVC homopolymer resin at 20 PHR, then the feed mix will have 20 Kg of stabilizer for every 100 kg of PVC resin.
Note that PHR is an indicator of concentration of various additives added to the feed mixture. The total price of the compounding mixture is derived from weighted average of price of individual components. For further reading please go through the post “How to calculate feed mix cost“. To convert parts per hundred resin/rubber values to Feed Mixture mass, utilize the following PHR to Total Feed Mix table.
Check out the video below for brief description on PHR followed by tutorial on using the PHR to Kg conversion sheet.
1) Start with entering the “Total Compounding mixture mass” required. The default PHR value of base resin/rubber is set to 100.
2) Add the PHR values for other additives.
An example is pre-loaded, edit it according to your process. The units of mass/weight are same as that of the “Total Compounding mixture mass”.
(Note : Calculation sheet may not open in AMP format. Open search result link in new tab to use the sheet or click here )
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