No long intro. Here's the bottom line: PET is resin code #1; polyethylene doesn't have one code; it's #2 for HDPE or #4 for LDPE; and Berry Plastics isn't Amcor yet. As of January 2025, Amcor had announced an all-stock combination with Berry Global, but regulatory approvals were still outstanding. If you're buying packaging, the logo matters less than the resin spec and the total delivered cost.
And before you click away to look up “resin sink”: in rigid packaging, that phrase usually means a molding defect—a small depression left where resin shrank as it cooled. It is not a new kitchen sink material. Fixing it starts with part design and process settings, not a more expensive resin.
Why I get to have an opinion
I manage procurement for a mid-sized consumer goods company. Over the past 6 years, I've tracked roughly $1.8 million in packaging spend, audited 30+ suppliers, and kept every quote in a cost system my finance team can verify.
I used to assume the cheapest per-unit price should win. It took three change orders in one quarter to teach me that total cost per usable part matters more: resin, tooling, freight, scrap, and the cost of a late delivery.
What is PET plastic? Only #1 if you're using the resin code
What is PET plastic? PET stands for polyethylene terephthalate. It's the clear, stiff polymer in soft-drink bottles, water bottles, and many clear clamshells. Its resin identification code is #1. Under ASTM D7611, that number identifies the polymer family for sorting. It does not say whether a product is recyclable in your area or whether it contains recycled content.
Per the FTC Green Guides (ftc.gov/green-guides), a resin code alone does not substantiate recyclable. A #1 code is not a sustainability badge. What most people don't realize is that resin codes were created to help recyclers sort materials, not to tell consumers which resin is “good.”
Polyethylene plastic number? There isn't one
The phrase “polyethylene plastic number” appears in search logs because people assume every plastic gets one number. Polyethylene is a family, not a single material. In the resin code system:
- #2 HDPE (high-density polyethylene): milk jugs, shampoo bottles, sturdy food jars.
- #4 LDPE (low-density polyethylene): bags, squeeze bottles, flexible films.
If you source containers, write the target code on the drawing. If a vendor says “it's polyethylene” without a resin code, ask for the ASTM D7611 code, a data sheet, and—for food contact—the relevant compliance document.
Is Berry Plastics now Amcor?
The short answer: no, not yet. Amcor and Berry Global announced a planned all-stock acquisition in late 2024. But until the deal clears regulatory and shareholder requirements, they remain two companies. If you have open purchase orders with Berry, do not move them to an Amcor portal based on a headline.
If you need the Amcor website, use amcor.com. I know the phrase “amcor website” sounds too obvious, but with lookalike domains and merger speculation, checking the official URL beats trusting a search snippet. Use the Amcor website's press or investor section to verify corporate changes before updating your vendor master.
Resin sink: what it actually means in packaging
When I first saw “resin sink” on a quality sheet, I imagined a resin kitchen sink. Our tooling engineer corrected me. A sink mark is a cosmetic defect on an injection-molded or thick-walled part. It happens because molten resin shrinks as it cools; thick sections can form a low spot after the outer skin has hardened.
My initial reaction was to upgrade the material. That's usually expensive and sometimes unnecessary. In our case, the processor added four seconds of cooling time and adjusted the rib thickness. The sink disappeared, and the annual material cost stayed flat. If a supplier tells you sink marks require a premium resin, ask to see their process data first.
Hidden fees are the real price risk
I still kick myself for choosing a quote that looked 12% lower until the tooling fee showed up on the invoice. That is why I now ask what's not included? before asking for a unit price. Transparent quotes—ones that list tooling, samples, freight, and validation—are easier to justify to management. Oh, and I've learned to verify the resin certificate too, because a quote is only as good as the material that shows up.
When Amcor appears in my RFQ list, we score it the same way as a regional converter. The supplier I keep is not necessarily the largest or the cheapest; it's the one whose quote lets me see the total cost. That's a form of trust I would rather buy.
Where this falls apart
My framework has limits. It works for food-grade rigid plastic packaging, not for medical devices, pressure vessels, or a resin sink in a bathroom. If your search for “resin sink” was about a kitchen sink, stop here: make the manufacturer name the resin family and the relevant ASTM test method. And for any part where safety depends on material properties, bring in an engineer; don't rely on a procurement blog.
I don't think Amcor—or any supplier—deserves a pass because it feels established. The same scrutiny applies in both directions: prove the resin, itemize the cost, and then I'm happy to sign.