Tolerances Normally, plastic bags/film in Great Britain should be within the tolerances according to British Standard – see BS7344, 1990 Width: Plus or minus 3mm (0.125”) or 2% whichever is greater Length: Plus or minus 6mm (0.25”) or 2% whichever is greater Gauge: Plus or minus 10%  

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Standards for plastic bags/film to use for food contact and medical application 1.Food Contact – To use Polythene film or bags inside European Union, in contact with food should comply with the relevant legislation on food contact including Great Britain. Great Britain: Statutory Instrument, 1998 No. 1376 and BPF-BIBRA (1995), Polymer Specification 4, Polyethylene EU: Commission Directive 90/128/EEC, 92/39/EEC, 93/9/EEC, 95/3/EEC and 96/11/EC, Section A. Example of a company comply with food contact: Polybags Limited 2.Medical use – Similarly, to use Polythene film or bags inside European Union, to produce containers for preparations for medico-pharmaceutical purposes should comply with the following regulation: European Pharmacopoeia - Monograph 3.1.3 "Polyolefin's" for medico-pharmaceutical purposes. The final responsibility for the decision of whether a material is fit for a particular application lies with the pharmaceutical firm. Example of a company comply with medical use: Polybags Limited

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Special options available in plastic bags or polythene film Clear or Coloured Polythene bag/film – Standard plastic bag either clear or coloured (tint, opaque) Plain or Printed Polythene bag/film – Standard plastic bag either plain or printed (1, 2 or multicoloured) Flat Polybags – Standard plastic bag often called by flat polybags Gusseted Poly bags – Plastic bags with fitted bottom and expandable sides (gusset) form to the shape of your product. Zipper/Zip lock bags – Bags with simple slide zipper which back and forth to open and close the bag. Seal seal/Reclosable bags - Grip seal bags have a simple plastic ridge that clicks shut and pulls open for continual re-use. Shrink film or bags - Bag/film which shrinks fit with the contents. Stretch film or bags – Stretch film also called a stretch wrap. Stretch film can stretch up to 100%. Drawstring bags – A bag that is closed at the top with a drawstring. Merchandise bags – A bag usually coloured and printed with logo, design or slogan which can be used for presentation. Single wound sheeting – Lay flat polythene tubing slit on both sides, creating 2 sheets on top of each other and wound separately called SWS(single wound sheeting) Centrefold sheeting – Lay flat tubing slit on one side before winding so that a long sheet is formed, that opens out to twice the film width Lay flat tubing – Polythene bubble collapsed and wound up forming a tube. Can be Gusseted at sides (so the bubble opens out to a larger width). Ideal for packaging long 'difficult to wrap' items. Insert into tubing and cut to required length then heat seal both ends to create made-to-measure bags. Double wound sheeting - Lay flat polythene tubing slit on both sides, creating 2 sheets on top of each other but wound together known as DWS (double wound sheeting) J-fold – A strip of material is removed from the polythene film before winding. Centre slit tubing – A polythene film slited from the centre and wounded on two different cores. Bags on roll - Bags attached by perforation and rolled up on a core Polythene or Polybags individually cut Carrier bags with Cut handle, Loop handle, Clip Close or Vest style

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Common resins used to make plastic bags are: Low density polythene (LDPE): Ethylene polymer with densities ranging from about 0.916 to 0.925 grams per cubic centimeter High density polythene (HDPE): Ethylene polymer with densities ranging from 0.941 to 0.965 grams per cubic centimeter Liner low density polythene (LLDPE): Ethylene polymer with densities ranging from 0.900 to 0.939 grams per cubic centimeter Medium density polyethylene (MDPE): Ethylene polymer with densities ranging from 0.926 to 0.940 grams per cubic centimeter Polypropylene (PP): A thermoplastic resin made by the polymerization of high-purity propylene gas in the presence of catalyst at relatively low pressures and temperatures. It is used to make film, fibers, rope and moulded articles Ethylene Vinyl Acetate (EVA): EVA compounded with LDPE is widely used to prevent plastic film/bags from cracking down to -30 degrees centigrade Polyvinyl chloride (PVC): Thermoplastic resin produced by the polymerization of the gas vinyl chloride [CH2CHCl]. Used in soft, flexible films for food packing. Also used in rigid products such as pipes or window profile.  

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How plastic bags is made? Most Plastic bags are made from polyethylene – more commonly known as polythene, which is made from crude oil and natural gas, non-renewable resources. The most common way to produce polythene bags is by blown film extrusion, also called the “tubular film process.” In Blown film production process - polythene melt is extruded through an annular slit die, usually vertically, to form a thin walled tube. Air is introduced via a hole in the centre of the die to blow up the tube like a balloon. into the tube causing it to expand and form a bubble. Mounted on top of the die, a high-speed air ring blows onto the hot film to cool it. The tube of film then continues upwards, continually cooling, until it passes through nip rolls where the tube is flattened to create what is known as a ' lay-flat' tube of film. This lay-flat or collapsed tube is then taken back down the extrusion ' tower' via more rollers. The lay-flat film is then either kept as such or the edges of the lay-flat are slit off to produce two flat film sheets and wound up onto reels. If kept as lay-flat, the tube of film is made into bags by sealing across the width of film and cutting or perforating to make each bag. This is done either in line with the blown film process or at a later stage.

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Food safety in China Chinese proverb says "Food doesn't harm you but careless words may." However, you can no longer say "food doesn't harm you". Nowadays, people choose food with exceptional caution. They buy vegetables with bugs and soak them for half an hour to avoid pesticides. They won't choose white noodles because artificial pigment has been added, and the same with chilli sauces. However, no matter how smart you are, there is no way you can stay away from unsafe foods. Over the past year there have been a number of food safety stories from China. The stories below demonstrate the risk to consumers, but also to investors in an industry that is now under enormous pressure to clean up its act. With a new food law on the drawing board for 2009, the question remains whether the 'Made in China' brand can claw its way back into export (and even domestic) markets. Sodium cyclamate in jujubes: The Urumqi Health Authority reported the discovery of illegally produced "red jujube" in the Toutunhe District on 18 August. Authorities found 10 tons of raw materials and finished products at the manufactory site. They also uncovered 14 bags of sodium cyclamate, 11 bags of saccharin-sodium, as well as a bag of alum. Workers turned "green jujubes" (raw jujubes) to "red jujubes" (ripe jujubes) by adding soy sauce, and then used saccharin-sodium and sodium cyclamate to make them sweet and tasty. Some of the products made it to market before the authorities could halt sales. "Do not eat oranges": So said a text message that spread rapidly by mobile phone in Guangyuan, Sichuan, around 20 October. The message said that "there are maggots in Guangyuan oranges" and that people shouldn't eat them. The government tried to hose down what was eventually reported as a rumour, but the case triggered panic among some consumers. People in China are worried about food safety; and with good reason. In response, China's top legislature approved the Food Safety Law on 28 February 2009, providing a legal basis for the government to strengthen food safety control "from the production line to the dining table." The law, which goes into effect later this year on 1 June will enhance monitoring and supervision, toughen safety standards, recall substandard products and severely punish offenders. A blue paper issued by the Chinese Academy of Social Sciences on 2 March states China should strengthen risk management to ensure food safety. The system, it says, should focus on evaluating the biological, chemical and physical dangers existent in food and food additives. An important component of the Food Safety Law is that it prohibits the Food Safety Supervision and Management Department from giving companies or products an exemption for food tests. This would seem vital now to resuscitate trust in 'Made in China' food products. Food safety is synonymous with a healthy life, so it is essential now that China (including food growers, manufacturers, retailers and various monitoring department) build trust.

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The business of packaging: Coca Cola in China (Thursday,19 March 2009)Today is a sad day for free trade as the Chinese government blocks Coca Cola's acquisition of China Huiyan Juice Group Ltd.  This acquisition would have promoted trade and investment in packaging at a time when the sector could use a boost.    A Double standard?  Yes, I think so.

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Flexible Packaging Trends for 2009 • Are you looking to make your food packaging a feature, not an added complication? • Are your marketeers telling you that they want something more from your packaging? • Are your retailer customers demanding that you met THEIR Cortauld commitment? Why don't you stay one step ahead of the marketplace, with my insights from what I have seen on the marketplace, compacted into a brief summary of the top 5 packaging trends for 2009: 1. Home compostable materials: to reduce packaging weight to landfill 2. Materials of % recycled content: to reduce content of virgin oil-based feedstock 3. Polypropylene reduction: there is limited opportunity to recycle PP at this moment in time 4. Pack weight reduction: to reduce tonnes of packaging to landfill 5. Convenience (reclosable, on-the-go packs, portion control): to add value whilst everyone else is downgauging I have heard a few decisions be made in 2008 that I think will be reversed. For example, I struggle to find agree with a move to a "recyclable" flexible, when we are still using depletable resources and sending to landfill. I think that carbon footprinting will become big in 2009 - so watch this space for advice on carbon footprinting your packaged product...  

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A Plastics Explosion - Polyethylene, Polypropylene, and Others Other plastics emerged in the prewar period, though some wouldn't come into widespread use until after the war. By 1936, American, British, and German companies were producing "polymethyl methacrylate" (PMMA), better known as "acrylic."  Although acrylics are now well-known for the use in paints and synthetic fibers, such as "fake furs," in their bulk form they are actually very hard and more transparent than glass, and are sold as glass replacements under trade names such as "plexiglas" and "lucite."  Plexiglas was used to build aircraft canopies during the war, and it is also now used as a marble replacement for countertops. Another important plastic, polyethylene (sometimes known as "polythene") was discovered in 1933 by Reginald Gibson and Eric Fawcett at the British industrial giant Imperial Chemical Industries (ICI).  This material evolved into two forms, low density polyethylene (LDPE) and high density polyethylene (HDPE). Polyethylene is cheap, flexible, durable, and chemically resistant.  LDPE is used to make films and packaging materials, including plastic bags, while HDPE is used more often to make containers, plumbing, and automotive fittings.  While PE has low resistance to chemical attack, it was found later that a PE container could be made much more robust by exposing it to fluorine gas, which modified the surface layer of the container into the much tougher "polyfluoroethylene." Polyethylene would lead, after the war, to another material, "polypropylene" (PP), which was discovered in the early 1950s.  It is common in modern science and technology that the growth of the general body of knowledge can lead to the same inventions in different places at about the same time, but polypropylene was an extreme case of this phenomenon, being separately invented about nine times.  It was a patent attorney's dream scenario, and litigation wasn't resolved until 1989. Polypropylene managed to survive the legal process, and two American chemists working for Phillips Petroleum of the Netherlands, Paul Hogan and Robert Banks, are now generally credited as the "official" inventors of the material.  Polypropylene is similar to its ancestor, polyethylene, and shares polyethylene's low cost, but it is much more robust.  It is used in everything from plastic bottles to carpets to plastic furniture, and is very heavily used in automobiles. Polyurethane was invented by Friedrich Bayer & Company of Germany in 1937.  It would come into use, after the war, in blown form for mattresses, furniture padding, and thermal insulation.  It is also used in non-blown form for sports wear such as "lycra." In 1939, I.G. Farben Industrie of Germany filed a patent for "polyepoxide" or "epoxy."  Epoxies are a class of thermoset plastics that form cross-links and "cure" when a catalyzing agent, or "hardener," is added.  After the war, they would come into wide use for coatings, "super glues," and composite materials. Composites using epoxy as a matrix include "fiberglass," where the structural element is glass fiber, and "carbon-epoxy composites," in which the structural element is carbon fiber.  Fiberglass is now often used to build sport boats, and carbon-epoxy composites are an increasingly important structural element in aircraft, as they are lightweight, strong, and heat-resistant. Two chemists named Rex Whinfield and James Dickson, working at a small English company with the quaint name of the "Calico Printer's Association" in Manchester, developed "polyethylene terephthalate" (PET or PETE) in 1941.  It would be used for synthetic fibers in the postwar era, with names such as "polyester," "dacron," and "terylene." PET is more impermeable than other low-cost plastics and so is a popular material for making bottles for Coke and other "fizzy drinks," since carbonation tends to attack other plastics, and for acidic drinks such as fruit or vegetable juices.  PET is also strong and abrasion resistant, and is used for making mechanical parts, food trays, and other items that have to endure abuse. PET films, trade-named "mylar," are used to make recording tape. One of the most impressive plastics used in the war, and a top secret, was "polytetrafluoroethylene" (PTFE), better known as "teflon," which could be deposited on metal surfaces as a scratchproof and corrosion-resistant, low-friction protective coating.  The polyfluoroethylene surface layer created by exposing a polyethylene container to fluorine gas is very similar to teflon. A Du Pont chemist name Roy Plunkett discovered teflon by accident in 1938.  During the war, it was used in gaseous-diffusion processes to refine uranium for the atomic bomb, as the process was highly corrosive.  By the early 1960s, teflon "non-stick" frying pans were a hot consumer item. Teflon was later used to synthesize the miracle fabric "GoreTex," which can be used to build raingear that in principle "breathes" to keep the wearer's moisture from building up.  GoreTex is also used for surgical implants; teflon strand is used to make dental floss; and teflon mixed with fluorine compounds is used to make "decoy" flares dropped by aircraft to distract heat-seeking missiles. After the war, the new plastics that had been developed entered the consumer mainstream in a flood.  New manufacturing was developed, using various forming, molding, casting, and extrusion processes, to churn out plastic products in vast quantities.  American consumers enthusiastically adopted the endless range of colorful, cheap, and durable plastic gimmicks being produced for new suburban home life. One of the most visible parts of this plastics invasion was Earl Tupper's "tupperware," a complete line of sealable polyethylene food containers that Tupper cleverly promoted through a network of housewives who sold Tupperware as a means of bringing in some money.  The Tupperware line of products was well thought out and highly effective, greatly reducing spoilage of foods in storage.  Thin-film "plastic wrap" that could be purchased in rolls also helped keep food fresh. Another prominent element in 1950s homes was "formica," a plastic laminate that was used to surface furniture and cabinetry.  Formica was durable and attractive.  It was particularly useful in kitchens, as it did not absorb, and could be easily cleaned of stains from food preparation, such as blood or grease.  With formica, a very attractive and well-built table could be built using low-cost and lightweight plywood with formica covering, rather than expensive and heavy hardwoods like oak or mahogany. Composite materials like fiberglass came into use for building boats and, in some cases, cars.  Polyurethane foam was used to fill mattresses, and styrofoam was used to line ice coolers and make float toys. Plastics continue to be improved.  General Electric introduced "lexan," a high-impact "polycarbonate" plastic, in the 1970s.  Du Pont developed "kevlar," an extremely strong synthetic fiber that was best-known for its use in bullet-proof vests and combat helmets.  Kevlar was so remarkable that Du Pont officials actually had to release statements to deny rumors that the company had received the recipe for it from space aliens. One of the most potentially important new developments in plastics is circuits made out of plastics called conductive polymers.  Electronic circuitry fabricated using plastics or other materials that could be simply printed on a substrate could be incredibly cheap, opening the door to throwaway electronic devices that would cost pennies, or to applications hardly dreamed of now. So far, electronic devices made with such materials have not been acceptable for production but, in 2001, prototypes of flat-panel displays based on such technologies were being publicly demonstrated, with predictions of commercial introduction in two or three years.

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An Introduction to the History of Plastics Plastic Polymers Plastics are polymers - long-chain carbon-based or "organic" molecules.  These chains are made up of repeating fundamental molecular elements, or "monomers." The term plastics covers a range of mostly synthetic or semi-synthetic organic condensation or polymerization products that can be molded or extruded into objects or films or filaments.  The name is derived from the fact the properties are in a semi-liquid state that is malleable, or has the property of plasticity.  Plastics vary immensely in temperature tolerance, hardness, resiliency.  Combined with this adaptability, the general uniformity of composition and lightness of plastics ensures their use in almost all industrial applications today. Natural Polymers People have been using artificial organic polymers for centuries in the form of waxes and shellacs.  A plant polymer named "cellulose" provides the structural strength for natural fibers and ropes, and by the early 19th century natural rubber, tapped from rubber trees, was in widespread use. Eventually, inventors learned to improve the properties of natural polymers.  Natural rubber was sensitive to temperature, becoming sticky and smelly in hot weather and brittle in cold weather.  In 1834, two inventors, Friedrich Ludersdorf of Germany and Nathaniel Hayward of the US, independently discovered that adding sulfur to raw rubber helped prevent the material from becoming sticky. In 1839, the American inventor Charles Goodyear was experimenting with the sulfur treatment of natural rubber when, according to legend, he dropped a piece of sulfur-treated rubber on a stove.  The rubber seemed to have improved properties, and Goodyear followed up with further experiments, and developed a process known as "vulcanization" that involved cooking the rubber with sulfur.  Compared to untreated natural rubber, Goodyear's vulcanized rubber was stronger, more resistant to abrasion, more elastic, much less sensitive to temperature, impermeable to gases, and highly resistant to chemicals and electric current. Vulcanization remains an important industrial process for the manufacture of rubber in both natural and artificial forms.  Natural rubber is composed of an organic polymer named "isoprene."  Vulcanization creates sulfur bonds that link separate isoprene polymers together, improving the material's structural integrity and its other properties. Some interesting polymers sites: Plastics, Yahoo

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