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T1 · Definition / IdentityAdditives & Compounding TechnologyGATE 2027 Syllabus (XE5)Shop-Floor Standard
Parts Per Hundred Resin (PHR) to Weight Percentage Conversion
Converts rubber and plastics recipe formulations written in Parts Per Hundred Resin (PHR) into exact weight percentage (wt%) for gravimetric feeder calibration.
Mathematical Canonical Relation
Plain Formula: wi = [ PHR_i / (100 + Sum(PHR_j)) ] * 100
Live Engineering Parameter Solver
Input your production or test values below for instant, verified output.
Verified Engine
target_phr
Range: 0.5 – 150 PHR
total_additive_phr
Range: 1 – 250 PHR
Calculated Engineering Result:
25 wt% (Resin is 62.5 wt%)
Engineering Verification:Total batch mass is 160 parts per 100 parts resin.
When & Where to Apply
Use when preparing twin-screw extruder loss-in-weight gravimetric feeder setpoints from laboratory rubber/PVC master formulation recipes.
Common Engineering Pitfalls
- Assuming PHR is identical to percentage (e.g., 40 PHR plasticizer is NOT 40% of the formulation)
- Forgetting to sum all additives in the denominator (plasticizer, stabilizer, filler, lubricant)
Physical Assumptions & Validity Limits
- Resin base is fixed at exactly 100 parts by definition
- All liquid and solid components summed in mass units
- Zero volatile solvent loss during weighing
Variable Symbols, SI Units & Dimensional Specifications
| Symbol | Variable Meaning | SI Unit | Typical Industrial Range |
|---|---|---|---|
| w_i | Weight percentage of ingredient i | wt% | — |
| \text{PHR}_i | Parts per hundred resin of component i | PHR | 40.0 |
| \sum \text{PHR}_j | Sum of all additives in formulation | PHR | 60.0 |
Worked Industrial Numerical Example: Flexible PVC Cable Compound DOP Plasticizer Conversion
Problem Statement:
A flexible PVC formulation contains: 100 PHR PVC resin, 40 PHR DOP plasticizer, 15 PHR CaCO3 filler, 3 PHR Ca-Zn stabilizer, 2 PHR lubricants. Total additives = 60 PHR. Convert 40 PHR DOP into wt%.
Step-by-Step Numerical Solution:
- Total batch weight = 100 (PVC) + 60 (Additives) = 160 parts
- Calculate wt% DOP = (40 / 160) * 100 = 25.0 wt%
- Calculate wt% PVC = (100 / 160) * 100 = 62.5 wt%
Final Answer: 25.0 wt% DOP (PVC = 62.5 wt%)
💡 Engineering Interpretation: 40 PHR DOP equals exactly 25.0% by weight of the final compound. A twin-screw loss-in-weight feeder must dose DOP liquid at 25.0% of total plant throughput rate.
Authoritative Technical Reference & Source Provenance
Plastics Additives Handbook by Hans Zweifel (Hanser, 2001), 5th Edition, Page 427-435.
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