Small portion flexible packaging

18 February 2021

Most consumers will at one time or another have come across those single serve sachets of Ketchup or brown sauce or those mini-tubs of margarine, butter or jam that are typically associated with a decision to eat out and at low cost. Sold in catering multi-packs to burger bar retailer chains, and to whoever heads up those family run cafés: these sachets, containing tiny tasters of mayonnaise, of mustard or of vinegar - liven up the driest, dullest and unhealthiest of café fare. But look around, more and more foods are appearing in individualised sized sachets or increasingly in composite pouches or single use containers.

More substantial than the taster sachets of table sauces or single serve sticks of instant coffee the newer single serve composite pouches, tubs and containers are ideal for those people seeking on the go convenience or who live on their own and don’t want the throwaway waste that normally occurs when buying larger portion/pack sizes. A printed portion-controlled pouch can be an aid for those seeking to lose weight or control weight for health reasons. A portion-controlled singe serve pouch or container that clearly displays calorific values and other health related information does away with the need for a weight concerned consumer to weigh food or guess how much a serving meets requirements.

For consumers on a tight budget or if you are the sole occupier of a property or even if you’re part of a family with widely differing tastes in food: buying food in large quantities can be wasteful with food left uneaten and food going to spoil. In circumstances such as just described single serve packaging makes sense.

One of the major growth sectors for portion-controlled foods is for retort pouches that can be popped into the microwave. While demographics and convenience drives demand to some extent, i.e., people living on their own, etc., food manufacturers, marketers and social scientists attribute year on year growth to other reasons the most important of which is that an increasing number of households don’t have a cooker. According to the Office of National Statistics and research undertaken by social scientists on behalf of universities - 11 percent of homes in the UK rely on a microwave for heating food – and the UK is not alone, the use of microwaves in place of conventional ovens is even more prevalent in the US. The reasons posited include the fact that many apartments simply don’t have the space for a cooker, others simply don’t have the time or inclination to cook.

Microwaveable pouches differ from other pouch products in that they do not have a foil layer. The vast majority of pouches incorporate either three or four layers of laminated material with an inner layer, often of polypropylene in contact with the food serving as a heat-sealing layer. To provide a barrier and to ensure the pouch and products contained within is at its best, a pouch may include: aluminium, ethylene vinyl alcohol (EVOH), silicon oxide or aluminium oxide. A pouch can be engineered to meet the specific requirements of the customer and application and may include for example a nylon layer and an outer layer of polyester. The former when used adds strength to the pouch and provides for puncture and tear resistance. An outer layer of polyester is heat resistant and is often reverse printed.

For microwaveable products silicone oxide and aluminium oxide coatings is used in place of foil. The silicate material in effect is a fine layer of flexible glass which provides for moisture resistance and a barrier to gases. For many products, polyurethane-based adhesives coated between various laminate layers hold the structure together. Pouches for products other than food may be manufactured using a combination of materials and processes, they may be gusseted, pillow configured or configured in some other way.

But it’s not just food that’s available in handy sized pouches and clear sealed bags or sachets. In high-street pharmacies and in the men’s toiletries and hair grooming section of supermarkets disposable razors, hair colour touch-up products, antiseptics and mini-travel packs can be found. In the well-being aisle, the cosmetic and make up aisle and in other sectors of interest to women: anti-bacterial wipes in mini-packs as well as try out sample sized sachets or pouches of shampoo, skin care and beauty products are on display. Other items on sale at leading stationers, office suppliers, airport outlets and many other retail points include memory cards/sticks and spare or replacements leads for laptops, smart phones and tablets, etc.

Retailing is not always about selling BIG: small does have its place, which is good news for narrow web printers and converters who are well placed to take advantage of that fact. Most narrow web presses are able to support and process a wide range of materials cost effectively and with quick turnarounds. Many of the flexible materials that go into the making of a composite pouch paper/poly/ foil or a cosmetic/sample: a poly/foil/poly sealant will generally run well without major modification to equipment, though as with everything there is a learning curve. Thinner gauge flexible materials can be more difficult, requiring converting equipment and presses optimised for filmic materials.

The development of any product doesn’t occur in isolation. Processing practicalities surface very quickly. Will the material readily convert? Is it easily printable? Am I using the most efficient method of coating/laminating or printing? How will the ink, the substrate/laminate interact over time? Are there different filmic or other materials that could be used? How do I find all of this out?

It takes time to ensure products perform seamlessly and if we broaden our view to look at the wider picture, we can see that it involves many different types of operation and many links that make up the supply chain. It involves R & D personnel and laboratories; film and other substrate providers; coating technologists and ink formulators as well as the printer/converter. When it comes to product development, trialling and monitoring it is useful to employ systems capable of undertaking the small-scale production of materials and consumables so that any issues that arise can be resolved prior to commercial commitment.

One such system is the VCML-Lab/Pilot Coater, which enables operators to print, coat and laminate on all types of flexible substrates and on a reel-to-reel basis. The VCML-Lab/Pilot Coater has a web width of up to 300mm, is touch screen-controlled and is equipped with a cantilevered unwind rewind, head mounting station with tray lift and trough and a laminator station with pneumatic nip.

The VCML-Lab/Pilot Coater can be used to apply various inks, varnishes, adhesives and even paint using environmentally acceptable formulations as well as, when necessary solvent-based materials. Short run production capability and the ability to experiment to determine the most suitable coating or other technology for a specific product or application is of great benefit. It is ideal for speedily bringing a product to market, trialling different formulae and materials, monitoring quality and for carrying out many types of tests and procedures.

Flexo, gravure, offset gravure/direct gravure, knife-over-roll, reverse coating, meter bar, slot-die coating and many other selectable technological processes are available. The VCML-Lab/Pilot Coater

can be configured for hot air drying, for infrared (IR) for UV curing and for corona treater. Edge guide and heated laminator and ATEX explosion proofing coating zone can also be integrated in with the system.

The coating of inks and other materials is all about being able to deliver a product with the optimum mix of aesthetic and performance properties. Application requirements differ often from day to day and those engaged in producing or using coatings must ensure customer expectations are met. Processing requirements and product sectors covered and the increasingly individualised nature of processing does mean that a single -quality control/ product development tool probably will never meet the needs of every customer.

RK Print Coat Instruments have designed and developed various pilot/production printing, coating and laminating systems as well as compact colour communication/sample preparation or coating and proofing devices so as to provide the widest choice for customers engaged in serving different industries.

The K Control Coater is a compact bench top system that enables users to quickly produce accurate and repeatable samples that can be used for quality control and presentation purposes, for research and development, for computer colour matching, etc. It is available in two versions, the 102 and model 202. The former offers a coated area of up to 170mm x 250mm and the model 202 has a coating area of 325 x 250mm – when fitted with meter bar coating and with a standard three-part bed.

The K Control Coater offers infinitely variable coating speeds of 2 to 15 m/min and controlled speed and pressure ensure repeatable results. Vacuum, magnetic, heated and glass beds are available, each of which can be easily added to the base machine.

Two types of vacuum beds are available, a type-A is recommended when coating onto delicate or extensible substrates such as polyethylene or aluminium foil. A type-B vacuum bed is a smooth aluminium faced bed with vacuum applied via multiple holes and which is suitable for more rigid materials.

A magnetic bed, type-C is suitable for use when coating onto magnetic substrates such as tin plate. A heated type-D is for applications that require heating, for example: hot melts. The smooth aluminium faced bed can be heated up to 200 degrees.

The gap applicator that can be supplied with the Control Coater is widely used for higher viscosity and thixotropic flows and for high coat weights; the micrometre adjustable applicator on the other hand is a versatile tool giving a coating width of 100mm or 200mm, producing a wet film thickness equal to the gap setting.

Spiral and close wound meter bars to suit standard and bespoke requirements are available. Close wound bars will produce coating thicknesses from 4 to 120 microns. Higher weights, up to 500 microns can be obtained using spiral wound bars.

In addition to the comprehensive line up of applicator technology – bird applicators providing a coating width of 100mm with gap sizes on up to 200 microns are available along with a 4-sided applicator device that enables the user to coat four separate film thicknesses with a single unit. Cube and K wedge bar extends applications possibilities still further.

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