Working with Moulders
As a materials manufacturer, Broadway adopts the ethos that we must be a valued partner to the plastic moulders we supply. We manufacture materials for use in a multitude of plastic manufacturing processes and our experience means we can offer reliable information and expert advice. We’ve been supplying injection moulders in the UK for 25 years, and rotational moulders have benefitted from our high-quality powders for the past decade.
Injecting our expertise
Broadway develops customised materials – including speciality compounds, to suit a number of niche requirements. Our technical knowledge and passion for innovation helps us support our customers in developing new products, embracing new ways of working and improving sustainability.
We’ve recently expanded our production capacity in response to increasing demand for large lot masterbatch orders and custom compounds. Whatever your requirement may be, you can be sure that Broadway will take the time to understand your processes, challenges and needs in order to deliver the right solution. Our products are relied upon for their colour accuracy and consistency in production and are always backed up by reliable and attentive customer service. We value each and every order – big or small.
If you simply need a colour quickly, then give us a call now. With next day deliveries achievable, our stocked universal masterbatch and roto powder range can ensure your production lines keep running. Below is a small selection of the manufacturers who have put their faith in Broadway.
We supply materials for use in the following production methods
Injection moulding is a batch process, normally used in the production of automotive components, bottle caps and other packaging items. A very similar process to Blow moulding, whereby a screw will mix and convey polymer and masterbatch through a heat barrel. The molten polymer mixture is pushed forward and eventually injected to fill the void in the mould. Once cooled the mould will open and eject the moulded component.
This is the most effective way to make storage containers, bottles, plastic drums and tubs. These are usually produced in a batch process. The cycle time is defined as the time it takes to complete one cycle of the process: from injection of the molten polymer to the release of the final moulded product.
The blow moulding machine consists of a heated barrel with a single screw element inside. The feed polymer is fed through the heated barrel, being conveyed by the screw. Eventually the softened polymer is pushed through and out of a die hole to form a tube shape.
The softened polymer tube is pushed into 2 halves of a mould which closes tight around the molten polymer tube. Once squeezed and sealed, it is inflated with air to form the desired shape according to the mould. The cooling process will harden the resulting polymer mould which will be ejected.
Injection stretch blow moulding (ISBM) is best known for producing PET bottles commonly used for water, juice and a variety of other products. One of the major advantages of stretch blow moulding is the ability to stretch the preform in both the hoop direction and the axial direction. This biaxial stretching of material increases the tensile strength, barrier properties, drop impact, clarity, and top load in the container. With these increases it is usually possible to reduce the overall weight in a container by up to 15% compared to other methods.
Single-stage stretch blow moulding uses the extruder to inject the polymer into a preform mould where the plastic is rapidly cooled to form the preform. The preform is then reheated and placed in the bottle mould. The then softened polymer stretches to about twice its original length. Compressed air is then blown into the stretched parison to expand to the bottle’s mould. Once the bottle is cooled the mould is opened and the finished bottle is emptied from the mould cavity. This technique is most effective in specialty applications, such as wide-mouthed jars, where very high production rates are not a requirement.
Two-stage stretch blow moulding is the same as single-stage, except the preforms are already made. The single-stage process is usually done using one machine, where the two-stage process uses preforms that have already been made and cooled. This allows companies to either make or buy their own preforms. Because of the relatively high cost of moulding, this is the best technique for producing high volume items such as carbonated beverage bottles. In this process, the machinery injection moulds a preform, which is then transferred within the machine to another station where it is blown and then ejected from the machine. This type of machinery is generally called injection stretch blow moulding (ISBM) and usually requires large runs to justify the very large expense for the injection moulds to create the preform and then the blow moulds to finish the blowing of the container. This process is used for extremely high-volume runs of items such as drinks bottles.
Film & Sheet Extrusion
There is a clear difference in definition between a sheet and film. To say ‘film’ to a polymer product, the thickness of the products must be below 0.5mm. A product between 0.5mm and 12.5mm, it is called a sheet. LDPE is generally used in film production.
In a similar way to other moulding processes, a screw will transport polymer through a heated barrel. The molten polymer will enter the die, and through the calendaring (cooling rollers) process in order to perfect the gauge and form the film or sheet. The calendaring process slowly cools the sheet until it is finished by either cutting to the desired size sheets or forming into roll stock.
Rotaional moulding provides a means of producing PE articles of a size and shape that cannot be manufactured economically in any other way. It is particularly suited for large, hollow, seamless parts such as industrial and agricultural tanks, kayaks, traffic bollards and marine floats – in fact anything that is hollow, enclosed or open-ended.
In this process a hollow mould is filled with a powdered polymer (typically LLDPE). The mould is slowly rotated around 2 perpendicular axis with heating, which encourages the polymer to melt and adhere to the inside of the mould. Mould rotation is constant and continuous throughout the heating and cooling phases to ensure an even wall thickness and to avoid deformation such as sagging, warpage and shrinkage.
3D printing is becoming increasingly popular. It’s ideal for low volume production runs, developing prototypes and intricate mouldings. Typically it uses CAD to create three-dimensional objects through a layering method. Usually using PA, ABS or PLA as the base resin, when heated the resins become pliable, they are deposited as layers according to the design and the process. This process extrudes the polymer, in filament form through a heated extruder to form layers and create the predetermined shape.
Because parts can be printed directly, it is possible to produce very detailed and intricate objects, often with functionality built in and negating the need for assembly.
Compatibility with your polymer of choice
Our custom masterbatches are polymer specific. This means they’re formulated for high performance when dosed into your chosen material. We can manufacture masterbatches for use with all the polymers outlined below, amongst others. If you’re running a material not listed here, please do get in contact with our expert technical team to see if we can meet your requirements.
Low Density Polyethylene – Slightly clearer than HDPE and far more flexible, mostly used for flexible packaging, carrier bags, flexible tubes, film applications etc. Like HDPE it has restricted transparent properties.
High Density Polyethylene – Slightly opaque white appearance used extensively in rigid bottle packaging, injection moulded caps and closures, crates etc. Its inherent whiteness can restrict the level of transparency achievable.
PPHO / PPCO
Polypropylene (Homopolymer, Block Copolymer, Random Copolymer)
PPCO Random & PPHO – Fairly clear polymer used in caps and closures. Also used to manufacture houseware products, buckets toys and storage boxes. Polypropylene is flexible with no real restrictions to colour or effects. Random copolymer is clearer than homopolymer and more suitable for translucent colours.
PPCO Block – PPCO but modified for greater impact strength. The additive turns the polymer white giving it a high level of opacity. This can restrict the transparency achievable.
Polyethylene-terephthalate – Polyesters are mechanically very strong and have good chemical resistance and barrier properties. PET is commonly used for making carbonated drinks bottles. In addition polyester can be spun and used to make textiles for clothes. PET is very clear which makes it good for translucent packaging, although a slight ‘yellowness’ can affect very light tints.
Polybutylene terephthalate – a thermoplastic crystalline engineering polymer that is often used as an insulator in electronics industries. It is a type of polyester with an excellent balance of properties and processing characteristics.
General Purpose Polystyrene – Glass clear but with very little impact strength it is most commonly used in CD cases. Its high level of clarity makes it good for translucent colours although an occasional violet tint can be visible.
High Impact Polystyrene – GPPS with the addition of an impact modifier to give greater impact strength. This additive turns the polymer white, various grades give different levels of opacity. Generally used for games pieces, toys etc. Its high level of whiteness makes translucent colours difficult to achieve. Specialist versions such as K-Resin and Styrolux are available on the market to give the same translucency as GPPS.
Acrylonitrile Butadiene Styrene – A tougher version of HIPS used in components with a higher added value. ABS is more durable than components manufactured in HIPS although it shares its difficulties in matching translucent colours. Like HIPS specialist translucent grades are available. Due to its durability, ABS is utilised in the manufacture of casings for power tools.
PA66 / PA6
Polyamide (6, 66) – Nylon is a general purpose grade which is widely used for mechanical construction and maintenance. This is due to its optimal combination of mechanical strength, stiffness and mechanical damping properties, together with a good electrical insulating ability. This is why electrical housing is made from nylon. PA66 is commonly used as a replacement to metal in various applications, the chemical and physical properties of PA6 are very similar to PA66. PA6 has better impact resistance and solubility resistance than PA66, but its moisture absorption is also stronger.
Styrene acrylonitrile copolymer – Transparent and with excellent chemical resistance, heat resistance and gloss, SAN also has good rigidity, tensile and flexural strength. Due to its high gloss appearance, SAN tends to be used in cosmetic packaging applications. SAN can cause problems when colouring in light tints due to the violet dyestuffs present in it. These are used to visually ‘clean it up’ when manufactured.
Polyethylene terephthalate Glyco – PET with glycol added. The Glycol is added to give better flow properties but decreases the strength. PETG can be extruded to form bottles and into sheets to make ‘blister’ type packaging.
TPE / TPU
Thermoplastic Elastomer/Thermoplastic polyurethane – TPU has many applications including automotive instrument panels, caster wheels, power tools, medical devices, and a variety of extruded film, sheet, and profile applications. TPEs are used in a variety of applications in the automotive, medical, construction, electrical, appliance, packaging, and industrial markets.