{"id":657,"date":"2026-04-27T06:59:36","date_gmt":"2026-04-27T06:59:36","guid":{"rendered":"https:\/\/isbm-blow-molding.com\/?p=657"},"modified":"2026-04-27T06:59:36","modified_gmt":"2026-04-27T06:59:36","slug":"pet-vs-petg-for-isbm-which-resin-fits-your-bottle-application","status":"publish","type":"post","link":"https:\/\/isbm-blow-molding.com\/th\/pet-vs-petg-for-isbm-which-resin-fits-your-bottle-application\/","title":{"rendered":"PET \u0e01\u0e31\u0e1a PETG \u0e2a\u0e33\u0e2b\u0e23\u0e31\u0e1a ISBM: \u0e40\u0e23\u0e0b\u0e34\u0e19\u0e0a\u0e19\u0e34\u0e14\u0e43\u0e14\u0e40\u0e2b\u0e21\u0e32\u0e30\u0e2a\u0e21\u0e01\u0e31\u0e1a\u0e01\u0e32\u0e23\u0e43\u0e0a\u0e49\u0e07\u0e32\u0e19\u0e43\u0e19\u0e02\u0e27\u0e14\u0e02\u0e2d\u0e07\u0e04\u0e38\u0e13"},"content":{"rendered":"
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MATERIAL SELECTION GUIDE<\/p>\n

PET \u0e01\u0e31\u0e1a PETG \u0e2a\u0e33\u0e2b\u0e23\u0e31\u0e1a ISBM: \u0e40\u0e23\u0e0b\u0e34\u0e19\u0e0a\u0e19\u0e34\u0e14\u0e43\u0e14\u0e40\u0e2b\u0e21\u0e32\u0e30\u0e2a\u0e21\u0e01\u0e31\u0e1a\u0e01\u0e32\u0e23\u0e43\u0e0a\u0e49\u0e07\u0e32\u0e19\u0e43\u0e19\u0e02\u0e27\u0e14\u0e02\u0e2d\u0e07\u0e04\u0e38\u0e13<\/h1>\n

PET and PETG share a similar chemistry but produce structurally different bottles. Choosing the wrong resin costs Korean manufacturers 15-30% in scrap rate, missed premium positioning, or over-spent material budget. This guide compares molecular structure, ISBM processing parameters, bottle performance, cost economics, and applications to match resin selection to Korean production requirements.<\/p>\n

Request Resin Compatibility Check \u2192<\/a><\/p>\n<\/div>\n<\/section>\n

<\/p>\n
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TL;DR \u2014 \u0e2a\u0e23\u0e38\u0e1b\u0e42\u0e14\u0e22\u0e22\u0e48\u0e2d<\/p>\n

PET is the semi-crystalline workhorse for beverage, water, and everyday cosmetic bottles at approximately 1,200 KRW\/kg. PETG is the amorphous glycol-modified copolyester for premium cosmetic, thick-wall jars, and high-clarity applications at approximately 2,500 KRW\/kg. Choose PET for high-volume commodity production and gas-barrier requirements. Choose PETG for premium visual quality, thick walls over 5mm, and impact-resistance applications. Both materials run on the same Ever-Power ISBM platforms but require different temperature profiles and cooling strategies.<\/p>\n<\/div>\n

<\/p>\n

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\u0e43\u0e19\u0e04\u0e39\u0e48\u0e21\u0e37\u0e2d\u0e19\u0e35\u0e49<\/h3>\n
    \n
  1. Why PET and PETG Are Often Confused<\/a><\/li>\n
  2. Molecular Structure & Material Chemistry<\/a><\/li>\n
  3. ISBM Processing Parameters Comparison<\/a><\/li>\n
  4. Bottle Performance Properties<\/a><\/li>\n
  5. Application Decision Matrix<\/a><\/li>\n
  6. Cost & Supply Chain Analysis<\/a><\/li>\n
  7. \u0e01\u0e32\u0e23\u0e08\u0e31\u0e1a\u0e04\u0e39\u0e48\u0e41\u0e1e\u0e25\u0e15\u0e1f\u0e2d\u0e23\u0e4c\u0e21 Ever-Power<\/a><\/li>\n
  8. Recycling & Sustainability<\/a><\/li>\n
  9. Korean Market Applications<\/a><\/li>\n
  10. \u0e04\u0e33\u0e16\u0e32\u0e21\u0e17\u0e35\u0e48\u0e1e\u0e1a\u0e1a\u0e48\u0e2d\u0e22<\/a><\/li>\n
  11. \u0e1a\u0e17\u0e2a\u0e23\u0e38\u0e1b<\/a><\/li>\n<\/ol>\n<\/div>\n

    <\/p>\n

    1. Why PET and PETG Are Often Confused<\/h2>\n

    PET and PETG share an almost identical chemical foundation. Both are polyethylene terephthalate based polyesters. Both exhibit excellent transparency. Both carry FDA and KFDA approval for food contact applications. Both recycle under the universal resin identification code 1 or 7 respectively. To a procurement manager reading spec sheets, the two materials appear interchangeable.<\/p>\n

    This similarity produces expensive selection mistakes. Korean manufacturers routinely specify PET for applications that require PETG’s impact resistance, then absorb 15-30% scrap rate from brittle bottle failures. Others specify PETG for commodity beverage applications, then carry a 200-400 KRW per bottle material premium that destroys the pricing position.<\/p>\n

    \"\u0e01\u0e32\u0e23\u0e43\u0e0a\u0e49\u0e07\u0e32\u0e19\u0e01\u0e32\u0e23\u0e09\u0e35\u0e14\u0e02\u0e36\u0e49\u0e19\u0e23\u0e39\u0e1b\u0e22\u0e37\u0e14\u0e40\u0e1b\u0e48\u0e32-5\"<\/p>\n

     <\/p>\n

    The technical reality is that one small molecular modification, the addition of cyclohexanedimethanol glycol to the polyester backbone, produces substantially different processing behavior, bottle performance characteristics, and commercial positioning. Understanding this modification is the foundation of resin selection discipline.<\/p>\n

    <\/p>\n

    2. Molecular Structure & Material Chemistry<\/h2>\n

    PET: Semi-Crystalline Homopolymer<\/h3>\n

    Polyethylene terephthalate (PET) is a semi-crystalline thermoplastic polymer produced through polycondensation of terephthalic acid (TPA) and ethylene glycol (EG). The resulting polymer chain is regular and symmetric, which allows polymer chains to align into crystalline regions during cooling below the glass transition temperature.<\/p>\n

    This crystallization behavior is simultaneously PET’s greatest strength and its processing challenge. Biaxial orientation during ISBM stretching organizes polymer chains into oriented crystalline structures that deliver exceptional bottle strength, gas barrier properties, and dimensional stability. However, uncontrolled crystallization during cooling produces opacity and haze that ruins bottle appearance.<\/p>\n

    \"\u0e01\u0e32\u0e23\u0e09\u0e35\u0e14\u0e02\u0e36\u0e49\u0e19\u0e23\u0e39\u0e1b\u0e22\u0e37\u0e14\u0e40\u0e1b\u0e48\u0e32\u0e2a\u0e33\u0e2b\u0e23\u0e31\u0e1a<\/p>\n

    PETG: Amorphous Glycol-Modified Copolyester<\/h3>\n

    PETG is produced by substituting approximately 30% of the ethylene glycol in the PET polymerization with cyclohexanedimethanol (CHDM). This substitution disrupts the regular polymer chain geometry and prevents crystalline alignment during cooling. The resulting material is amorphous, meaning it does not form crystalline regions regardless of cooling rate.<\/p>\n

    The amorphous structure produces exceptional optical clarity in thick-wall applications where PET would haze. It also produces superior impact resistance because amorphous polymer chains absorb energy through chain slippage rather than crystalline crack propagation. The trade-off is reduced barrier properties (no crystalline structure to impede gas permeation) and lower service temperature (no crystalline melt transition to resist deformation).<\/p>\n

    \n\n\n\n\n\n\n\n\n\n\n
    Molecular Property<\/th>\n\u0e2a\u0e31\u0e15\u0e27\u0e4c\u0e40\u0e25\u0e35\u0e49\u0e22\u0e07<\/th>\n\u0e1e\u0e35\u0e17\u0e35\u0e08\u0e35<\/th>\n<\/tr>\n<\/thead>\n
    Polymer structure<\/td>\nSemi-crystalline homopolymer<\/td>\nAmorphous copolyester<\/td>\n<\/tr>\n
    Glycol composition<\/td>\n100% ethylene glycol<\/td>\n70% EG + 30% CHDM<\/td>\n<\/tr>\n
    Glass transition temp (Tg)<\/td>\n75-80\u00b0C<\/td>\n80-85\u00b0C<\/td>\n<\/tr>\n
    Melting point<\/td>\n245-260\u00b0C (crystalline)<\/td>\nNo discrete melt (amorphous)<\/td>\n<\/tr>\n
    Crystallinity behavior<\/td>\nForms crystals on slow cooling<\/td>\nStays amorphous<\/td>\n<\/tr>\n
    Density<\/td>\n1.38-1.40 g\/cm\u00b3<\/td>\n1.27-1.30 g\/cm\u00b3<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

    <\/p>\n

    3. ISBM Processing Parameters Comparison<\/h2>\n

    The molecular differences translate directly to measurably different ISBM processing windows. Operators switching between PET and PETG on the same platform must adjust five parameter groups.<\/p>\n

    \n\n\n\n\n\n\n\n\n\n\n\n\n
    \u0e1e\u0e32\u0e23\u0e32\u0e21\u0e34\u0e40\u0e15\u0e2d\u0e23\u0e4c\u0e01\u0e32\u0e23\u0e1b\u0e23\u0e30\u0e21\u0e27\u0e25\u0e1c\u0e25<\/th>\n\u0e2a\u0e31\u0e15\u0e27\u0e4c\u0e40\u0e25\u0e35\u0e49\u0e22\u0e07<\/th>\n\u0e1e\u0e35\u0e17\u0e35\u0e08\u0e35<\/th>\n<\/tr>\n<\/thead>\n
    Pre-drying temperature<\/td>\n165-170\u00b0C<\/td>\n65-70\u00b0C<\/td>\n<\/tr>\n
    Pre-drying time<\/td>\n4-6 \u0e0a\u0e31\u0e48\u0e27\u0e42\u0e21\u0e07<\/td>\n4-6 \u0e0a\u0e31\u0e48\u0e27\u0e42\u0e21\u0e07<\/td>\n<\/tr>\n
    \u0e1b\u0e23\u0e34\u0e21\u0e32\u0e13\u0e04\u0e27\u0e32\u0e21\u0e0a\u0e37\u0e49\u0e19\u0e40\u0e1b\u0e49\u0e32\u0e2b\u0e21\u0e32\u0e22<\/td>\n<50 ppm<\/td>\n<40 ppm<\/td>\n<\/tr>\n
    Melt temperature<\/td>\n260-280\u00b0C<\/td>\n220-250\u00b0C<\/td>\n<\/tr>\n
    \u0e2d\u0e38\u0e13\u0e2b\u0e20\u0e39\u0e21\u0e34\u0e41\u0e21\u0e48\u0e1e\u0e34\u0e21\u0e1e\u0e4c<\/td>\n15-20\u00b0C (rapid quench)<\/td>\n20-30\u00b0C (moderate)<\/td>\n<\/tr>\n
    Stretch temperature window<\/td>\n90-110\u00b0C<\/td>\n85-100\u00b0C<\/td>\n<\/tr>\n
    Typical cycle time (250ml)<\/td>\n9-11 \u0e27\u0e34\u0e19\u0e32\u0e17\u0e35<\/td>\n10-13 seconds<\/td>\n<\/tr>\n
    Processing window forgiveness<\/td>\nNarrow (requires tight control)<\/td>\nWider (more forgiving)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

    The single most important processing difference is the drying temperature. PET absorbs moisture aggressively and requires high-temperature desiccant drying at 165-170\u00b0C to reach <50 ppm residual moisture. PETG handles moisture more gracefully and only requires 65-70\u00b0C drying. Operators switching from PET to PETG must reset drying profiles or risk polymer degradation.<\/p>\n

    The second key difference is stretch temperature tolerance. PET requires precise preform temperature control in a narrow 90-110\u00b0C window for optimal biaxial orientation without overheating into crystallization. PETG offers a wider forgiving window because it does not crystallize regardless of stretch conditions. This makes PETG significantly easier to process reliably, particularly for operators new to ISBM.<\/p>\n

    <\/p>\n

    4. Bottle Performance Properties<\/h2>\n

    The finished bottle performance differences are substantial and drive most application decisions.<\/p>\n

    \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
    Performance Property<\/th>\nPET Bottle<\/th>\nPETG Bottle<\/th>\n<\/tr>\n<\/thead>\n
    Optical clarity (thin wall)<\/td>\n\u0e22\u0e2d\u0e14\u0e40\u0e22\u0e35\u0e48\u0e22\u0e21<\/td>\n\u0e22\u0e2d\u0e14\u0e40\u0e22\u0e35\u0e48\u0e22\u0e21<\/td>\n<\/tr>\n
    Optical clarity (thick wall >5mm)<\/td>\nHaze risk<\/td>\nGlass-like clarity<\/td>\n<\/tr>\n
    Impact resistance<\/td>\nModerate (brittle when cold)<\/td>\nHigh (ductile down to -40\u00b0C)<\/td>\n<\/tr>\n
    Rigidity \/ stiffness<\/td>\n\u0e2a\u0e39\u0e07<\/td>\n\u0e1b\u0e32\u0e19\u0e01\u0e25\u0e32\u0e07<\/td>\n<\/tr>\n
    Gas barrier (CO2, O2)<\/td>\n\u0e22\u0e2d\u0e14\u0e40\u0e22\u0e35\u0e48\u0e22\u0e21<\/td>\n\u0e1b\u0e32\u0e19\u0e01\u0e25\u0e32\u0e07<\/td>\n<\/tr>\n
    Chemical resistance<\/td>\n\u0e14\u0e35<\/td>\nBetter (alcohols, detergents)<\/td>\n<\/tr>\n
    Stress crack resistance<\/td>\n\u0e1b\u0e32\u0e19\u0e01\u0e25\u0e32\u0e07<\/td>\n\u0e22\u0e2d\u0e14\u0e40\u0e22\u0e35\u0e48\u0e22\u0e21<\/td>\n<\/tr>\n
    Maximum service temperature<\/td>\n60-65\u00b0C (standard)<\/td>\n65-70\u00b0C<\/td>\n<\/tr>\n
    Gamma sterilization<\/td>\nLimited compatibility<\/td>\nFully compatible<\/td>\n<\/tr>\n
    UV resistance<\/td>\n\u0e14\u0e35<\/td>\nBetter<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

    Three performance dimensions drive most Korean selection decisions:<\/p>\n