Moisture ≤0.4% Good Processing Performance PET Resin for Flavoring Containers

Moisture ≤0.4% Good Processing Performance PET Resin for Flavoring Containers

Problem

Flavoring and condiment containers require precise, repeatable molding, yet moisture in the resin causes bubbles, silver streaks and weak weld lines.

Those defects show up as reject rates of 3-8% and cause leaks in sauce and seasoning packaging.

Because flavoring containers are often thick-walled, moisture defects are more visible and more damaging than in thin bottles, and each bubble or streak is a potential leak point.

Sauce and seasoning packs that leak in transit are rejected at the warehouse, so a small moisture problem becomes a full-shipment loss.

Cause

PET is hygroscopic; water absorbed into the pellet hydrolyzes the melt, breaking polymer chains and releasing AA.

Each 100 ppm of excess moisture can cost several percent of IV, and trapped vapor forms voids in thick container walls.

Because flavoring containers are often thick-walled, moisture defects are more visible and more damaging than in thin bottles.

PET is hygroscopic and absorbs water from air; that water hydrolyzes the melt, breaking polymer chains and releasing acetaldehyde while trapped vapor forms voids.

Each 100 ppm of excess moisture can cost several percent of intrinsic viscosity, weakening the wall exactly where thick containers need strength.

In thick walls the vapor has farther to travel and more time to form voids before the part sets, so the defect rate scales with wall thickness.

Solution

This grade is supplied at moisture ≤0.4% and with low dust for clean, stable feeding.

The dry pellets reduce hydrolysis, so melt strength holds and thick walls fill without bubbles or streaks.

Good processing performance means consistent cycle times and fewer rejects on sauce and seasoning lines.

Supplying the resin at moisture 0.4% or below and with low dust reduces hydrolysis, so melt strength holds and thick walls fill cleanly without bubbles or silver streaks.

Good processing performance translates into stable cycle times and fewer rejects on sauce and seasoning lines, improving both yield and delivery reliability. Cleaner molding also reduces maintenance on hot runners and molds.

Selection Guide

• Choose this grade for thick-wall condiment and flavoring containers.
• Always dry to below 50 ppm before molding, regardless of incoming moisture.
• For deep-draw or heavy containers, use the upper IV end for melt strength.
• Pair with a low-dust grade to protect feeding systems and reduce contamination.

Application Scenarios

• Flavoring, sauce and condiment containers.
• Food seasoning and edible-oil bottles.
• Thick-wall food packaging requiring defect-free walls.

FAQ

Why does moisture cause bubbles?
Trapped water turns to vapor in the melt, forming voids; it also hydrolyzes PET and lowers IV.

Do I still need to dry the resin?
Yes, dry to below 50 ppm at 160-170°C; supplied low moisture is not a substitute for line drying.

Is it safe for food contact?
Yes, it is FDA and EU REACH compliant.

What IV suits thick containers?
Use 0.80-0.82 dl/g for the melt strength needed in heavy walls.

IV Viscosity Differences & Bottle Type Matching

The main difference between the PET grades is the IV viscosity of PET, which decides the type of bottle each grade is used for:

Low IV (0.780–0.800 dL/g) suits thin-wall still water and hot fill bottles; medium IV (0.830 dL/g) suits oil, cosmetics and APET sheet / roll; high IV (0.855–0.875 dL/g) builds the wall strength and stress-crack resistance needed by CSD, fast-reheat and gallon bottles.