Kev faib khoom tseem ceeb thiab qhov txawv ntawm zaj duab xis nplawm

Hauv kev ntim khoom lag luam, cov khoom siv tseem ceeb uas siv rau zaj yeeb yaj kiab nplawm feem ntau yog raws li Linear Low-Density Polyethylene (LLDPE). Los ntawm kev siv comonomers sib txawv, cov khoom ntxiv, thiab thev naus laus zis co-extrusion ntau txheej, muaj ntau hom kev faib khoom me me.

hauv qab no yog cov kev faib khoom tseem ceeb uas tam sim no muaj nyob hauv kev lag luam thiab lawv qhov txawv tseem ceeb:

1. Kev faib khoom siv tseem ceeb

Raws li cov khoom siv tseem ceeb (comonomers) thiab kev hloov kho tshwj xeeb, cov zaj duab xis nthuav dav hauv kev lag luam raug faib ua plaub pawg tseem ceeb:

C4-LLDPE (Butene Copolymer Film)

• Cov yam ntxwv ntawm cov khoom: Siv Butene ua comonomer. Qhov no yog cov khoom siv niaj hnub tshaj plaws, siv dav tshaj plaws, thiab txuag nqi tshaj plaws cov ntaub ntawv zaj duab xis nthuav dav ib txwm muaj hauv khw.
• Applications: Haum rau cov qauv niaj hnub, general cargo wrapping and lightweight packaging that does not require high stretch ratios or puncture resistance.

C6 / C8-LLDPE (Hexene / Octene Copolymer Film)

• Cov yam ntxwv ntawm cov khoom: Incorporates longer carbon-chain monomers—Hexene or Octene. The long-chain branching structure gives the molecular chains much better entanglement capabilities.
• Performance Upgrades: Compared to C4, it delivers a massive step up in stretch ratio, tear strength, and puncture resistance.
• Applications: Ideal for heavy-duty pallet wrapping, cargo with sharp corners or edges, and high-speed pre-stretch automatic wrapping machines.

mLLDPE (Metallocene Stretch Film)

• Cov yam ntxwv ntawm cov khoom: Produced using metallocene catalysts. It features a narrow molecular weight distribution and a highly regular chemical structure.
• Performance Upgrades: The absolute “gold standard” of stretch film. It boasts extreme toughness, superior puncture resistance, excellent optical clarity (transparency), and outstanding holding force—allowing it to be downgauged (made thinner) without sacrificing strength.
• Applications: High-end packaging requirements, high-speed fully automated wrapper lines, and export products targeting source-reduction and ultra-thin packaging specifications.

PCR / Biodegradable Eco-Friendly Film (Emerging Mainstream)

• Cov yam ntxwv ntawm cov khoom:
  • PCR (Post-Consumer Recycled): Reclaimed plastic is repelletized and blended with virgin resins at specific ratios (e.g., 30% rau 50%).
  • Biodegradable: Biodegradable masterbatches are added to traditional LLDPE, or bio-based materials are used to comply with stringent environmental and low-carbon import regulations in European and North American markets.
• Applications: Perfect for multinational supply chains with strict compliance targets for sustainability, carbon reduction, and green initiatives.

2. Core Performance Comparison

For a direct comparison, we can evaluate these four materials across five key dimensions—stretch ratio, puncture resistance, cling property, clarity, and cost:

Key Metric	C4 Conventional Film	C6 / C8 High-Performance Film	mLLDPE Metallocene Film	PCR Recycled Eco-Film
Theoretical Pre-Stretch Ratio	100% – 150%	200% – 300%	300% – 400%+	Varies by blend (slightly lower than virgin material)
Puncture & Tear Resistance	Standard (prone to sharp-edge piercing)	Excellent (highly resistant to tearing)	Superior (extremely difficult to puncture)	Moderate (slightly reduced due to recycled impurities)
Clarity & Gloss	Average	Good	Outstanding (crystal clear)	Slight haze or minor yellowish tint
Load-Holding Force	Moderate (prone to loosening)	High	Superb (retains tight tension long-term)	High
Comprehensive Cost	Highly Economical (Lowest)	Moderate	Higher (but offset by downgauging potential)	Involves technology or certification premiums

3. Manufacturing Process Dimension: Cast vs. Blown Film

Beyond raw materials, the manufacturing process also fundamentally dictates film performance and application scenarios:

• Cast Stretch Film:
  • Features: Dominates the market, accounting for over 80% of total production. It typically utilizes 3-layer, 5-layer, or even 7-layer co-extrusion technology.
  • Pros: Exceptional clarity, highly uniform thickness gauge, extremely low unwind noise (silent film), and excellent double-sided cling.
  • Cons: Excellent longitudinal (machine direction) stretch, but transverse (cross-direction) tear resistance is slightly inferior to blown film.
• Blown Stretch Film:
  • Features: Produced via a blown film die, where the resin is inflated into a bubble and cooled by an air ring.
  • Pros: Molecules are oriented in both machine and cross directions, yielding unmatched puncture and tear resistance in all directions.
  • Cons: Lower clarity compared to cast film, less uniform thickness, and due to the nature of the tackifier additives, it produces high noise levels during unwind.

💡 Sourcing & Application Recommendations

1. Manual Wrapping / Light Loads: Opt for C4 Cast Film to achieve the best cost efficiency.
2. Semi-Automatic / Standard Machine Wrapping (Stretch Ratio < 250%): Choose C6/C8 Cast Film to perfectly balance strength and cost-effectiveness.
3. High-Speed, Fully Automated Unmanned Lines (Pre-Stretch > 300%): High-spec composite films rich in mLLDPE (Metallocene) are mandatory to ensure smooth operations without film breaks, optimizing overall throughput.
4. Exporting to North American / European Markets with Green Barriers: Prioritize PCR Recycled Stretch Films with proper certifications to meet local plastic tax exemptions and environmental compliance requirements.