Matching MFI and Density Is Not Enough
Two polyethylene grades can show similar melt-flow and density values while processing differently or producing different finished-product performance. A proper substitution review must compare the exact producer grade, test conditions, molecular and additive characteristics, process behavior, compliance and customer qualification requirements.
Jiuting Polymers uses the buyer’s current producer TDS, application and specification as the starting point. We can screen relevant China-origin options, but final suitability must be established through buyer document review, sampling, production trials and approval.
1. Confirm the Material Identity
- Polymer family: HDPE, LDPE, LLDPE or another PE type
- Current producer and complete grade designation
- Country of origin if restricted by the buyer or project
- Natural, colored or pre-compounded material
- Virgin, recycled or defined blend requirement
- Intended processing method and finished application
2. Compare Melt Flow Correctly
MFI or MFR must include the test temperature and load. Values measured under different conditions cannot be compared directly. The required flow also depends on the process: a blow-molding container, blown film, coating line, pipe extrusion and injection-molded part may require very different melt strength and flow behavior even when the numerical value appears close.
3. Check Density and Resin Structure
Density influences stiffness and other performance, but it does not fully describe the resin. Depending on the PE family and application, the comonomer, molecular-weight distribution, branching, melt strength and crystallization behavior may affect processing and finished properties.
4. Review Application-Critical Properties
Film
- Bubble stability and output
- Dart impact, tensile, tear and puncture
- Seal initiation, seal window and hot tack
- Clarity, haze, gloss and film feel
- Shrink response where applicable
Blow Molding
- Parison control and swell
- Container weight and wall distribution
- ESCR for the filled product
- Drop, impact and stacking tests
Pipe
- Defined material classification
- Applicable standard and compound form
- Long-term and crack-resistance documentation
- Project, utility or country approval
5. Compare Additive Packages
Confirm slip, antiblock, processing aid, antioxidants, UV stabilizer, antistatic agent, color and other additives. A buyer using separate masterbatch may require an additive-free base resin. A change in additive package can affect film opening, printing, winding, odor, color, processing and compliance.
6. Check Regulatory and Customer Approval
- Food-contact requirements
- Drinking-water or gas-pipe requirements
- Medical, hygiene or chemical-packaging requirements
- Destination-country regulations
- Customer-specific approved producer or grade lists
- Required TDS, COA, MSDS and producer reports
An approval or test report for one producer and grade cannot automatically be transferred to another grade.
7. Review the Production Line
Provide the machine type, screw and die information where relevant, number of layers, line speed, output, processing temperature, pressure, blend ratio and current operating window. A material can look acceptable on paper but require unacceptable processing changes on the actual line.
8. Define the Trial and Acceptance Criteria
Before a sample is tested, agree on what success means. Record the reference material, production conditions, sample quantity, finished-product tests and acceptable limits. Compare both processing stability and final performance. Do not approve a material only because the first few minutes of the trial run smoothly.
9. Confirm Commercial and Supply Requirements
- Required monthly or annual quantity
- Minimum acceptable lot consistency
- Packing and pallet requirement
- Destination port
- FOB, CFR or CIF term
- Required delivery window and document set
A technically acceptable material may still be unsuitable if its supply continuity, lot size, documentation or logistics do not fit the buyer’s production plan.
Recommended Substitution Workflow
- Send the current producer grade and complete TDS.
- Identify the mandatory process, performance and compliance items.
- Compare exact candidate producer documents.
- Review sample COA and current MSDS when available.
- Conduct a controlled trial using recorded conditions.
- Test the finished product against agreed acceptance criteria.
- Approve commercially only after technical and supply requirements pass.
Request a PE Grade Comparison
Email the current producer and grade or TDS, application, critical parameters, additive and compliance requirements, quantity and destination port to sales@jiutingpolymers.com. We will determine whether a technically relevant China-origin option can be screened. No substitution is considered confirmed until the buyer completes its own qualification.