PET Preforms

1. What is a PET Preform?

A PET preform is a precursor to a plastic bottle that is made from polyethylene terephthalate (PET) and looks like a test tube with a molded neck suitable for receiving a cap or closure. PET preforms are converted into plastic bottles through a manufacturing process called blowmolding.

2. What type of plastic are PET preforms made from?

Preforms are made from polyethylene terephthalate (PET), the most widely recycled form of plastic in the world. PET plastic is a versatile material that is suitable for a wide variety of bottles and containers, especially those used in the beverage industry. Although most PET preforms are made from 100% virgin PET resin, they may also be made from up to 100% post-consumer recycled (PCR) content.

3. What is blow-molding?

Blow-molding is the manufacturing process used to convert PET preforms into plastic bottles or containers. The process consists of (a) heating the body of the preform so the plastic becomes soft and then (b) blowing air into the neck of the preform so the heated plastic expands to take the shape of the bottle or container mold surrounding the preform.

4. How are PET preforms produced?

PET preforms are produced through a manufacturing process called injection molding. The injection molding process consists of injecting molten PET into a preform mold. The preform mold features an open end in the shape of a bottle or container neck and a closed end in the shape of a cylindrical tube. The shape of the bottle or container neck is designed to receive a corresponding cap or closure that screws or snaps on to the neck.

5. Do PET preforms come in different colors?

Yes. Although PET preforms are typically produced in natural-colored plastic, yielding clear, translucent bottles or containers, they may be colored or tinted by adding a colorant, also known as masterbatch, to the PET resin used in the injection molding process. The most common color tints are blue and green, yielding translucent bottles or containers of the same tint. Preforms can also be colored to produce opaque bottles.

6. What are the most important specifications or parameters for purchasing a PET preforms?

There are three important specifications for purchasing PET preforms. The most important specification is the neck finish, or shape of the preform neck designed to receive a particular cap or closure. A neck finish will typically identify the desired diameter of the bottle neck, as well as the particular type of neck threading, which will determine what types of caps or closures will work with the neck. Common neck finish categories include tamper-evident, which feature numerous subcategories like 28mm PCO 1810 and 28mm PCO 1881, and continuous thread, such as 28-400, 28-410 and 28-415. The preform weight, measured in grams, is another important specification because it will determine the size of the bottle or container that will be blow-molded using the PET preform. As a general rule, the heavier the preform, the larger the bottle or container it can produce. Finally, the preform color or tint is another important specification because it will determine whether the bottle is clear or tinted a certain color. Generally, there is an upcharge for colored/tinted preforms.

7. How are PET preforms priced?

PET preforms are typically priced by the thousand (i.e., per one-thousand units). PET preform pricing is highly dependent on and driven by the global market price of PET resin. As PET preforms increase in gram weight so too will their cost.

8. How are PET preforms packed?

PET preforms are generally packed in two different ways, namely in gaylords or in cases. Gaylords are large, heavy-duty cardboard boxes that sit on a standard pallet (48” x 40”) and will typically hold thousands of preforms depending on their neck diameter and gram weight. Cases are smaller corrugated cardboard boxes that typically hold hundreds of preforms. Gaylords are the preferred method of packing PET preforms because they are efficient to handle and may be double-stacked during transport, such as in truck or shipping container. Whether ultimately packed in gaylords or cases, PET preforms will be supplied in plastic bags that are sealed at the factory for safety, security, and sanitation.

9. How can I get PET preform samples?

You can obtain PET preform samples by contacting your KGI representative. Samples are typically available free of charge.

10. Do you supply PET preforms made with Post-Consumer Recycled (PCR) content?

Yes, we supply PET preforms with up to 100% post-consumer recycled, or PCR, PET resin on a made-to-order basis. Oftentimes, a preform made from PCR resin will feature a certain percentage of PCR, such as 50% PCR resin (and 50% virgin resin), depending on the desired attributes of the bottle to be blown. Bottles made from PCR resin generally have a darker tint compared to bottles made from 100% virgin PET resin.

11. What are the most common types of PET preforms?

The most common types of PET preform feature a tamper-evident neck finish for beverage applications, such as for bottled water or carbonated soft drinks.

Examples of tamper-evident neck finishes include 28mm PCO 1810 (or 1816), 28mm PCO 1881, 29/25, 38mm, 48mm, and 55mm.

12. What are common problems when purchasing preforms?

Purchasing preforms can present a buyer with a number of different challenges. First, a particular preform manufacturer may not produce all of a buyer's preform requirements. This will prompt the buyer to source and purchase from different factories, thereby increasing complexity. Next, a buyer may face long lead times from a given factory they are working with. The lead time is a function of the time to produce the preforms and subsequently transport them to the buyer's location, such as by ocean or road, or a combination of these two common modes of transport. Finally, a buyer may face high minimum order quantities, or MOQs, from a given manufacturer they are working with. High MOQs may make it impractical or even financially impossible to work with a given manufacturer. KGI helps to solve these common problems by representing a wide range of manufacturers across four continents, thereby providing us with the world's largest PET preform portfolio. Additionally, KGI stocks millions of the most common preforms throughout its network of warehouse locations, thereby shortening lead times for its customers, not to mention eliminating high MOQs.

13. Can PET preforms help “lightweight” my bottles?

Yes. Certain PET preforms are designed for the specific purpose of reducing the amount of plastic in the resulting bottle. For instance, 28mm PCO 1881 preforms feature a shorter neck compared to its predecessors, namely 28mm PCO 1810 or 28mm PCO 1816 preforms, which feature a longer neck. The shorter the neck, the lower the weight of the resulting bottle. Additionally, 29/25 and 26mm preforms provide other new and exciting opportunities for lightweighting plastic bottles and reducing plastic waste.