Confirm the Exact Packaging Project

An inquiry stating “PET resin for Coca-Cola preforms” does not provide enough information to select a grade.

The buyer should first identify the receiving customer, destination market, preform specification, and intended bottle format. A material that has performed successfully in another carbonated beverage application should still be assessed against the requirements of the new project.

Start by confirming:

• The receiving bottler or packaging customer.
• Bottle capacity, preform weight, and neck finish.
• The applicable material and preform specifications.
• Whether virgin PET, rPET, or a specified blend is required.
• Any restrictions on resin producers, manufacturing sites, or grades.
• Who is responsible for approving a new material or supply source.

Verify What Any Approval Claim Actually Covers

Statements such as “Coca-Cola approved,” “used for Coca-Cola bottles,” or “suitable for Coca-Cola preforms” should lead to further questions rather than immediate acceptance.

Ask the supplier to explain the claim and provide evidence that can be checked through the appropriate customer contact. Establish whether the evidence relates to the supplier, resin producer, manufacturing facility, material grade, or a particular packaging project.

Useful verification questions include:

• Which legal entity and manufacturing site does the evidence identify?
• Does it name the exact resin grade being offered?
• Is the evidence current and relevant to the intended receiving operation?
• Are there conditions, limitations, or additional qualification steps?
• Does the proposed purchasing route comply with the customer’s sourcing requirements?

Identify the Producer, Manufacturing Site, and Supply Route

A PET resin distributor may offer material from several producers, while a producer may operate multiple manufacturing facilities. Procurement records should therefore identify the actual material source rather than relying only on a brand name.

Before ordering, confirm:

• Resin producer and exact grade designation.
• Manufacturing facility or source identification.
• Original packaging and label information.
• Production batch or lot number.
• The seller’s role in the supply chain.
• Whether any repacking, relabeling, or intermediate storage is involved.

If the customer specifies a particular source, make that source part of the purchase order. Avoid leaving room for an unreviewed substitution under descriptions such as “equivalent grade” or “same IV material.”

Review the Documentation as a Complete Package

A technical data sheet is useful for initial screening, but it is only one part of a purchasing decision. Buyers should organize the documents by purpose and check that they refer to the material actually being offered.

Check consistency across documents. The grade on the quotation should match the purchase order, bag label, batch certificate, and shipping records.

Compare More Than the Nominal IV

Intrinsic viscosity is an important PET property, but matching IV values do not establish that two grades will behave identically.

Buyers should compare the full material specification and processing guidance. Relevant review points may include IV, color, acetaldehyde, pellet condition, contamination controls, and reheat characteristics, according to the project requirements.

Alpek’s technical information for one commercial CSD resin, for example, discusses reheat behavior, temperature distribution in thick-wall preforms, crystallization behavior, and acetaldehyde performance.

The comparison should answer three separate questions:

1. Does the PET resin grade meet the agreed incoming-material specification?
2. Can it be processed consistently on the intended injection equipment?
3. Do the resulting preforms produce bottles that meet the customer’s requirements?

Confirm Virgin PET and Recycled-Content Requirements

The material composition needs to be established before comparing quotations.

Ask whether the project requires virgin PET, a specified recycled-content percentage, or a particular recycled material. Also confirm how that requirement is documented and controlled.

For a project using a blend, buyers should clarify who supplies each component and who controls blending. The PET resin supplier, preform manufacturer, and receiving customer need a consistent understanding of the specified formulation.

Where rPET is involved, request the relevant source, traceability, food-contact, and quality documentation. Do not assume that a recycled material accepted in another application is automatically acceptable for this project.

Likewise, a virgin CSD bottle grade PET resin should not be proposed as a direct replacement when the packaging specification requires recycled content. The offered material must match both the technical and composition requirements.

Agree on the Trial Plan Before Ordering Trial Material

A useful trial has predefined acceptance criteria. Without them, a supplier and buyer may interpret the same production results differently. Before the trial, agree on the material quantity, reference grade, equipment, operating conditions, sampling plan, and evaluation responsibilities.

Record Injection Molding Performance

The trial record should document the actual drying and molding conditions rather than simply state that the resin “processed well.”

Depending on the agreed plan, useful observations may include process stability, cycle time, reject rate, preform appearance, weight consistency, and dimensional results.

Drying deserves particular attention. PET absorbs moisture, and inadequate drying can cause hydrolytic degradation during melt processing.

Evaluate the Preforms

Inspect the trial preforms against the applicable drawing and quality requirements.

Potential evaluation items include neck dimensions, weight, visual defects, color, clarity, gate condition, and other customer-specified characteristics.

Retain labeled samples and connect them to the resin lot and processing record. This makes subsequent bottle testing and investigation easier.

Complete the Required Bottle Evaluation

The agreed validation plan should cover blowing and any finished-package tests required by the customer. Depending on the application, these may include material distribution, pressure performance, stress cracking, dimensional stability, carbonation retention, and storage evaluation.

These are possible evaluation categories, not a universal Coca-Cola test protocol. The customer should define the required methods, conditions, and acceptance limits.

Check Shipment Integrity and Incoming Release

Material verification continues after the order is placed.

Before dispatch, confirm the agreed packaging, lot identification, document package, shipment quantity, and transport arrangements. On arrival, inspect packaging condition and reconcile the received lots with the supplied records.

The buyer’s incoming-control process should address damaged bags, unclear labels, missing certificates, or discrepancies between ordered and delivered material.

Store and handle the resin according to the supplier’s guidance and the plant’s procedures. Preserve lot identification through storage, drying, and production so finished preforms remain traceable to the original material.

Compare the Cost of Qualified Supply

Once eligibility and technical requirements are established, compare commercial offers on the same basis.

A lower price per ton may offer little benefit if the material requires additional qualification, produces more rejects, arrives with incomplete records, or cannot be supplied consistently.

Consider:

• Material price and freight.
• Trial and qualification costs.
• Observed production yield and processing performance.
• Lead time and supply continuity.
• Documentation and technical support.
• Payment terms and complaint-resolution arrangements.

The strongest purchasing comparison uses verified production and delivery information. Avoid assuming that an alternative will reduce manufacturing costs solely because its quoted resin price is lower.

Frequently Asked Questions

This article provides a general procurement framework, not a Coca-Cola technical specification or approval guide. Chemate Group is an independent PET resin supplier. References to Coca-Cola do not imply affiliation, endorsement, or authorized-supplier status.