As a bottling solution it is undeniable that PET (Polyethylene terephthalate) plastic has the upper hand over all other alternatives such as glass and metal.
Plastic has an array of qualities that make it an irresistible option for many brand owners, and which include light weight, minimal wastage, versatility, ability to take attractive and unique designs, and a carbon neutral footprint.
Taking all this into perspective, things can only be expected to get better for the growing PET plastic bottle manufacturing industry, and indeed the wider plastics industry.
There are lots of numbers in support of this position.
A study by Research and Markets found that the 2014 global production of plastic containers stood at 50.1 Million Metric Tons (MMT). By 2020 this is expected to rise to 67.9 MMT. That 2014 figure was worth $273.15 billion; the 2020 figure is expected to be $388.35 billion.
As a sector, the plastic bottle manufacturing gross output has been showing steady growth over the years as can be seen in the chart below:
The growth pattern is still on the up in 2017.
Research shows that plastic bottles and jars constitute an estimated 75% of all plastic containers by weight. Also, PET and HDPE (high-density polyethylene) make up 86% of the plastic container market.
The same report also indicates that PET is currently a favorite for bottlers as its use results in cost savings for raw polymers, energy and transportation. Their PET bottle designs are a hit with their customers considering their attractive packaging and sustainability qualities.
Of note is that PET plastic bottles are increasingly being used for beer bottling.
All these details make for exciting prospects but there is a caveat for anyone intent on launching a PET plastic bottle manufacturing small business: there is a lot of competition. As such, you’ll have to do all you can to make every aspect of your business competitive.
Here’s some of what you must know when getting started:
1. What exactly is PET?
PET, also abbreviated as PETE, stands for Polyethylene Terephthalate, commonly known as polyester.
For the chemistry-inclined the structure for a PET molecule looks like this:
PET was first synthesized in the mid-1940s by the chemists at DuPont who were seeking to create a new synthetic fiber. They named the fiber they produced “Dacron”; this is what we now know as “Polyester”. Where the same molecule is used for making containers it is known as PET or PET resin.
The PET bottle was patented in 1973 by chemist Nathaniel Wyeth; four years later the first PET bottle was recycled and converted into a bottle base cup. Thereafter, more recycling uses have been developed. PET bottles are now recycled into carpets, textiles and non-wovens.
Lots of research has gone into ensuring that PET bottle manufacturing reflects today’s environmental concerns. The effort is definitely very promising.
For example, just 35 grams of raw material is used to create a 1.5 liter PET bottle.
This PET raw material, aka PET resin, is supplied by resin manufacturers in the form of tiny pellets, with each pellet weighing approximately 0.05 g.
2. Qualities and reasons why PET is preferred for making bottles
Some of the reasons why PET is an ideal packaging material include:
- Excellent clarity thus making it ideal for product presentation
- It does not alter product taste — thereby complying with international food contact regulations
- Structural toughness which prevents breakage during production, warehousing and transportation
- It is shatter-proof. In the event of failure a container will split but not shatter
- It has high impact and tensile strength and therefore ideal for carbonated products which exert high pressure inside containers
- It has low permeability to oxygen, carbon dioxide and water thus ably protecting product and assuring shelf life
- Good chemical resistance
- It’s lightweight. This allows for cheaper shipping, excellent shelf utilization and sufficient stacking
- Zero-leakage of PET bottles. This is as a result of having an injection-molded neck finish and a base that doesn’t feature a weld line
- It allows for a wide range of design flexibility in terms of size, shape, color, neck finish, etc
- It is completely recyclable
3. Understand what customers look for in a plastic bottle manufacturer
Anyone in the market for a PET plastic bottle manufacturing service approaches the matter with a view to getting a solution that will work best in helping them to achieve their overall objective.
Knowing what customers require, therefore, will, from the onset, enable you to optimally position yourself as a go-to PET bottle manufacturer, in effect giving your business a fighting chance in a crowded market.
Customers want to know:
- Whether to source PET bottles locally or from overseas. While bottles can be much cheaper overseas one will still need to factor in substantial shipping costs
- What types of plastics a manufacturer uses to produce bottles. This is informed by the intended use of the bottle
- Whether or not a manufacturer will provide closures for the bottles. If so, what types of closures are available? If not, where will closures be acquired?
- What to go for i.e. readymade or custom-designed bottles
- What the minimum order level of bottles is
- Whether or not a manufacturer is capable of printing and/or labeling the bottles as per a customer’s requirements
- Whether or not a manufacturer is capable of meeting the legal requirements and industry standards for the production of certain type of bottles
- The options available to them in case the bottles fail to meet quality requirements or if batches are not delivered on time
- What track record and reputation a manufacturer has in the market
4. The two PET bottle manufacturing techniques
There are two methods of producing PET plastic bottles:
- One-step aka “hot perform” method
- Two-step aka “cold perform” method
For both techniques the production process can be illustrated as follows:
The only difference between the two processes is that the one-step technique machine makes its own preforms (the orange test tube-like object shown in step 1) but the two-step technique utilizes readymade preforms previously created via injection molding.
5. More details about the one-step method
The one-step method involves a single integrated machine that performs all the 3 or 4 required steps involved in creating a PET bottle as follows:
- (Conditioning / temperature adjusting)
- Container ejection
Seeing as the PET raw material has to remain in elastic form for the entire process, temperatures inside the machine are constantly high. However, the one-step method results in higher energy savings, compared to the two-step method, because heating is only done once i.e. when the raw material is being converted into a preform.
Also, because individual preforms don’t come into contact with foreign objects during the process, the resulting bottle almost always has a glossy and unblemished surface.
Importantly, the one-step process results in lower output than the two-step process but the cost of the machine used is substantially cheaper than the investment required to acquire the two machines used in the two-step process.
This is the process to use in case you want to easily mold other material types, in addition to PET. Some of these other materials include Polypropylene (PP), Polyethylene Napthalate (PEN), Polycarbonate (PC) and Recycled PET.
Note that for PET production the one-step machine requires a number of support equipment including:
- Dehumidifying resin dryer
- Mold Chiller (8°C to 14°C range)
- Cooling Tower to provide water for non-critical cooling at 25°C to 30°C
- Compressors supplying air for operation (0.9MPa) and for blowing (up to 3.4MPa)
- Mold Dehumidifier (depends on local ambient conditions)
- Mold Temperature Controller unit (depends on container design)
Just to recap, the one-step process is characterized by the following:
- Lower electricity consumption
- Lower resource requirements because preforms don’t have to be packed, stored and transported
- A cycle speed of roughly 43 seconds
- Suitability for the production of all container types, regardless of weight and neck design, as one isn’t only restricted to the preforms currently available in the market
- Superior bottle gloss and clarity; surface deterioration due to preform storage and transport is out of the question
- The need for peripheral equipment
- Difficulty in assessing preform quality before blow molding — this requires the equipment operator to be seasoned enough and thus able to determine when and where defects are occurring
6. More details about the two-step method
For the two-step process, also known as re-heat stretch blow molding, two separate machines are used:
- An injection molding machine to produce preforms
- A reheat blowing machine (RHB) to convert the preforms into bottles as shown below
This requirement allows companies to either acquire both machines to do everything in-house OR just purchase preforms for in-house processing.
The option of doing everything in-house results in energy losses because heat is lost during the transfer of the preforms to the RHB where they have to be reheated.
Note that the RHB machine is relatively expensive.
There are some noteworthy concerns about the two-step process:
- Due to preform transfer the resulting PET bottles and containers will typically have blemished surfaces
- During the reheating of preforms the difference in internal and external temperatures limits the scope of blow molding. As a result there is difficulty in producing square bottles, flat bottles, and bottles with handles
- It’s impossible to orient necks unless you put a notch into the preform transfer bead
- The preforms must have a neck bead in order to be transferred into the RHB
- Molding alternative materials isn’t as easy as when using the one-step process
7. Which of the two will suit your business model best?
In choosing between the one-step and two-step production processes for your plastic PET bottle small business you have to consider your potential products’ specific circumstances and requirements.
You also have to think about factors such as capital costs, preform availability, container volumes and technical difficulty.
Issues including productivity, product application, energy consumption, efficiency, machine footprint and environmental concerns must also be weighed.
Nevertheless, the comparison given above is quite telling.
For a new PET bottle manufacturer seeking to make headway in a crowded industry, it is rather obvious that one-step PET bottle production is the way to go.
This will give you much more versatility unlike in the two-step production scenario where you’ll be contending against bigger players who are better suited for higher output production, stiff competition and low profit margins.
For the purpose of this guide, therefore, the assumption is that your business will employ one-step PET bottle production.
8. About new bottle designs and obtaining molds
As has been observed previously, one-step production is ideal for producing non-standard bottle shapes. It’s also suitable for low outputs.
These two qualities will combine to give your PET bottle manufacturing business a measure of versatility and flexibility that’ll allow you to find and serve customers who have markedly different product requirements.
Catering to such customers will of course entail the production of completely new bottle designs as determined by individual specifications.
This will in turn require you to procure new molds designed to create the required bottles and preforms designs.
9. Issues to be considered when designing a new PET bottle, corresponding preform, and mold
In designing a new PET bottle, structural qualities are given priority over aesthetics.
The following illustrations will help to clarify why this is so and why it’s vital to consult experienced bottle designers:
- A bottle intended to store a carbonated drink must be able to withstand the carbon dioxide pressure (typically 4 atmospheres) and maintain shape during storage (which involves stacking). Such a bottle must therefore have the required wall thickness, base design and adequate top load strength.
- A bottle intended for packaging juice or other perishable should be able to withstand hot-filling conditions that would cause a standard PET bottle to shrink and deform.
- Where a bottle is designed to be lightweight with an aim to lower production costs, provisions must be made to assure its rigidity. Ribs/ridges can be added in this case to prevent collapsing.
For the preform, it’s important to select the most appropriate design in order to assure the success of the new bottle design. Some of the factors that come into play here include:
- Having preform dimensions that will complement bottle dimensions and resin stretch ratios
- Required neck finish and part weight
- Preform length as determined by bottle height and axial stretch ratio
- Preform core (inside) diameter as determined by bottle diameter and hoop stretch ratio
- Design of preform transition region (between its neck straight and body) as determined by factors such as bottle shoulder shape and preform mold stack design
Having arrived at a workable bottle design, a model of the same is created by means of computer-aided design (CAD). This document illustrates how a 1 Lt. PET bottle can be designed by this means.
Using the new bottle design a mold will be produced.
The procedure will involve the following:
- Selection of appropriate material followed by surface grinding
- Computer programming and preparation for CNC machine production
- Production of the mold followed by heat treatment and hand-polishing of its components
- Mold assembling and then installation on the one-step machine
10. Production of PET plastic bottles, possible defects, and possible production challenges and risks
The graphic in point no.4 is but a representation of how a blow molding machine converts a preform into a bottle.
The process is not so straight-forward in reality. Various factors and practices must be correctly applied to ensure successful PET bottle production.
Your operation will therefore have to prioritize the following blow molding requirements:
- Insisting on accurate preform and bottle designs
- Using the right grade of PET resin pellets
- Making high-quality preforms using excellent injection molding technique
- Ensuring that the preform has the required temperature profile before it’s transferred to the blow molding stage
- Ensuring that all stages (stretch, pre-blow and blow) are perfectly timed
- Ensuring that the equipment and molds are in good condition and in compliance with GMP and OSHA requirements
- Ensuring that peripheral services including chilled water and compressed air are adequately supplied
Some of the defects you may encounter during production include:
- Production of Acetaldehyde (AA) in which case an acidic taste (similar to citrus fruits) is imparted to the liquid in the bottle. This can have disastrous consequences especially where the liquid concerned, e.g. water, cannot mask this taste. AA production occurs alongside PET production when the temperature of the preforms injection molding exceeds 260°
- This and other technical defects are explained here.
- Defects that can result from production negligence e.g. leakage, poor tensile strength, undesired shapes and sizes, uneven thickness, etc.
The following can interfere with your otherwise efficient production schedule:
- Electricity outages
- Equipment breakdown, more so the peripheral machines
- Equipment servicing routine visit
- Industrial action and other situations affecting labor availability
- Bank holidays
The risks involved in running a PET plastic manufacturing outfit can generally be placed under four categories i.e.:
- Health and safety — Exposures that can result in injury or illness
- Property exposures — These are related to fire (equipment malfunction, flammable materials, etc.) and damage to key components e.g. molds
- Product safety and the complications/legalities that arise from doing business globally e.g. product standards and regulations, third-party transfers, etc.
- Risks involving transactions and online information transfer
Any underwriter willing to insure your PET manufacturing small business will most likely refer to a checklist like this which highlights various physical damage and time element exposures.
11. How to run a profitable PET plastic bottle manufacturing small business
Perhaps the best way to approach this would be to calculate how much you will use to manufacture a single PET plastic bottle.
Having obtained this figure you will be able to set a price that will offset your production costs and give you a healthy profit margin.
With the help of such a bottle cost estimator that takes into account factors like capital machinery, leasehold improvements, production calculations, labor assumptions, resin cost, electrical operating cost, depreciation and interest rate, you can actually have a pricing strategy that is based on a well informed standpoint.
Profitability will of course require you to minimize production defects and uphold blow molding good practices.
12. Marketing your PET plastic bottle manufacturing small business
Whatever marketing strategy you plan on employing there is one inescapable fact about the plastics manufacturing industry: It is highly competitive and features big players with massive brand recognition and small players with aggressive pricing strategies.
Strategies for breaking into the PET plastic bottle market will obviously differ.
Nevertheless, in as far as your digital marketing strategy will be concerned, knowing the following will be helpful:
- The two top channels that industry B2B marketers use to generate revenue and drive leads are email and organic search
- Industry B2B buying habits reveal that substantial online research precedes offline work-related purchases. This is therefore your cue to have an online presence and omni-channel capacity
- The top five website requirements that industry B2B buyers check for are pricing information, technical support details, helpful content, shipping information and a testimonials/client list
- The top content marketing tactics that manufacturers use to connect with their target audiences are illustrations/photos, video, in-person events, social media content (excluding blogs) and e-Newsletters