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Monday, January 27, 2014

Active packaging

The terms active packaging, intelligent packaging, and smart packaging refer to packaging systems used with foods, pharmaceuticals, and several other types of products. They help extend shelf life, monitor freshness, display information on quality, improve safety, and improve convenience.
The terms are closely related. Active packaging usually means having active functions beyond the inert passive containment and protection of the product. Intelligent and smart packaging usually involve the ability to sense or measure an attribute of the product, the inner atmosphere of the package, or the shipping environment. This information can be communicated to users or can trigger active packaging functions.
Depending on the working definitions, some traditional types of packaging might be considered as "active" or "intelligent". More often, the terms are used with new technologically advanced systems.
For many years, desiccants have been used to actively control the water vapor in a closed package. A desiccant is a hygroscopic substance usually in a porous pouch or sachet which is placed inside a sealed package. They have been used to reduce corrosion of machinery and electronics and to extend the shelf life of moisture sensitive foods and drugs.
Corrosion inhibitors can be applied to items to help prevent rust and corrosion. Volatile corrosion inhibitors (VCI) or vapor phase corrosion inhibitors can be provided inside a package in a pouch or can be incorporated in a saturated over wrap of special paper. Many of these are organic salts that condense on the metal to resist corrosion. Some films also have VCI emitting capability.
Films are available with copper ions in the polymer structure; these neutralize the corrosive gas in a package and deter rust.
VCI create a neutral environment in the packaging. It works on the principle of difference in vapour pressure and causes reaction with Metals and Non metals and also with Moisture to render it active to corrosion. There are different forms of VCI's available like Papers, Plastics, HDPE Papers, Oils, Foams, Bubble, and Emitters etc. that can prevent corrosion at many stages.

Friday, January 24, 2014

Poly Shrink Film Manufacturing Process


Shrink packaging has been well established for over three decades. Due to it's practical and cost related advantages, it has found its use in many industries at various stages of packaging process.
Shrink Packaging can be divided into following groups:
a)Primary- where the product is totally enclosed for protection from abrasion, dust, moisture and for improved appeal.
b)Secondary- where a group of items is wrapped together to form a Sales unit, (Six-packs of Beer, Juice etc)
c)Distribution packaging-Where product is wrapped into a distribution unit which may stacked directly on the pallet ready for transportation. When walking through supermarket one only has to look on top of the shelves to see the extent of use of this packaging method.Most grocery and high volume beverage products will use cardboard trays for added rigidity of the pack. While the use tray is not always necessary, it does provide improved handling in automated warehouses.


Shrink Packaging Process
Shrink wrapping, bundle wrapping, etc, is a process during which a product item or a group of items in wrapped in a loose sleeve or envelope of plastic film, which upon application of heat shrinks and tightly conforms to the shape of enclosed contents. The key element of this process is Shrink Film.Shrink Film can be made from a variety of materials each having different strength, shrink characteristics transparency and lustre.


Polyvinylchloride (PVC), Polypropylene (PP) and Polyethylene (PE) are the three most commonly available materials.PVC, being one of the first materials used, is now being phased out due to its toxic properties, although still used abundantly in underdeveloped countries. Low Density Polyethylene (LDPE) is best suited for general packaging applications due to its relatively high strength and low cost.

Polyethylene Shrink film is manufactured in a vertical extrusion process where ethylene granules are heated under pressure to produce Polyethylene polymer.The polymer is forced upwards through a circular extrusion die to produce a very thin walled continuous tube of material, still in a semi-molten state as it emerges from the die. A controlled supply of air is fed up through the centre of the die to stretch the tube in the radial direction, thus forming a bubble. At the same time the tube is stretched in length by winding the film at a faster than it is extruded. As the film cools, the induced stretch is "memorized" in the film. Upon reheating the film, if unrestrained, will shrink a certain percentage in the width, referred to as % Shrink in TD (transverse direction), and in the length, % shrink in MD (machine direction).At the top end of the bubble the film tube is cool enough to be flattened and wound off as Lay-flat tubing, alternatively, it can be slit at one edge to produce Centre-folded material or slit at both edges to produce Flat sheet.




Tuesday, January 21, 2014

Plastic embossed films manufacturer

Plastics extrusion is a high volume manufacturing process in which raw plastic material is melted and formed into a continuous profile. Extrusion produces items such as pipe/tubing, weather stripping, fence, deck railing, window frames, plastic films and sheet, thermoplastic coatings, and wire insulation.
In the extrusion of plastics, raw thermoplastic compound material in the form of nurdles (small beads, often called resin in the industry) is gravity fed from a top mounted hopper into the barrel of the extrudes. Additives such as colorants and UV inhibitors (in either liquid or pellet form) are often used and can be mixed into the resin prior to arriving at the hopper. The process has much in common with plastic injection moulding from the point of the ext ruder technology though it differs in that it is usually a continuous process. While pultrusion can offer many similar profiles in continuous lengths, usually with added reinforcing, this is achieved by pulling the finished product out of a die instead of extruding the fluid raw material through a die.
The material enters through the feed throat (an opening near the rear of the barrel) and comes into contact with the screw. The rotating screw (normally turning at up to 120 rpm) forces the plastic beads forward into the barrel which is heated to the desired melt temperature of the molten plastic (which can range from 200 °C (392 °F) to 275 °C (527 °F) depending on the polymer). In most processes, a heating profile is set for the barrel in which three or more independent PID controlled heater zones gradually increase the temperature of the barrel from the rear (where the plastic enters) to the front. This allows the plastic beads to melt gradually as they are pushed through the barrel and lowers the risk of overheating which may cause degradation in the polymer.
Extra heat is contributed by the intense pressure and friction taking place inside the barrel. In fact, if an extrusion line is running certain materials fast enough, the heaters can be shut off and the melt temperature maintained by pressure and friction alone inside the barrel. In most extruders, cooling fans are present to keep the temperature below a set value if too much heat is generated. If forced air cooling proves insufficient then cast-in heater jackets are employed, and they generally use a closed loop of distilled water in heat exchange with tower or city water

Friday, January 17, 2014

Flexography

Frequently used for printing on plastic, foil, acetate film, brown paper, and other materials used in packaging, flexography or flexographic printing uses flexible printing plates made of rubber or plastic. The inked plates with aslightly raised image are rotated on a cylinder which transfers the image to the substrate. Flexography uses fast-drying inks, is a high-speed print process, can print on many types of absorbent and non-absorbent materials, and can print continuous patterns (such as for giftwrap and wallpaper).Some typical applications for flexography are paper and plastic bags, milk cartons, disposable cups, and candy bar wrappers. Flexography printing may also be used for envelopes, labels, and newspapers.Originally, flexographic printing was rudimentary in quality. Labels requiring high quality have generally been printed using the offset process until recently
The greatest advances in flexographic printing have been in the area of photopolymer printing plates, including improvements to the plate material and the method of plate creation.Digital direct to plate systems have been a good improvement in the industry recently. Laser-etched ceramic anilox rolls also play a part in the improvement of print quality. Full-color picture printing is now possible, and some of the finer presses available today, in combination with a skilled operator, allow quality that rivals the lithographic process. One ongoing improvement has been the increasing ability to reproduce highlight tonal values, thereby providing a workaround for the very high dot gain associated with flexographic printing.

Monday, January 13, 2014

Film Embossing Process

Film embossing is a mechanical process in which a flat film is transformed into an embossed product. During the process, thermal and stress fields are applied to the polymer, causing changes in the microstructure and physical dimensions of the material. The engineering analysis of the process requires the study of various aspects relating to the characterization of the microstructure before and after embossing, A variety of techniques were employed to characterize the properties and microstructure of the embossed film in relation to crystallinity, orientation, mechanical properties, and dimensions of the embossed films. The thermal treatment of the polymer film was shown to be the most significant factor in the process. By controlling the thermal treatment of the film, it is possible to manipulate the properties and dimensions of the embossed film. The important aspects: influencing thermal treatment include the radiation heater temperature, preheat roll temperature, line velocity, and film thickness. The initial film orientation and embossing pressure have a minor effect on the final properties of the embossed film. The main effect of the embossing pressure is on the bulk thickness of the embossed film.

Tuesday, January 7, 2014

Poly shrink film manufacturers

Shrink wrap, also shrink film, is a material made up of polymer plastic film. When heat is applied, it shrinks tightly over whatever it is covering.Heat can be applied with a hand held heat gun (electric or gas) or the product and film can pass through a heat tunnel on a conveyor.The most commonly used shrink wrap is polyolefin. It is available in a variety of thicknesses, clarities, strengths and shrink ratios. The two primary films can be either crosslinked, or non crosslinked. Other shrink films include PVC and several other compositions.Coextrusions and laminations are available for specific mechanical and barrier properties for shrink wrapping food. For example, five layers might be configuration as EP/EVA/copolyester/EVA/EP, where EP is ethylene-propylene and EVA is ethylene-vinyl acetate copolymer.A shrink film can be made to shrink in one direction (unidirectional or mono-directional) or in both directions (bidirectional).
Films are stretched when they are warm to orient the molecules from their initial random pattern. Cooling the film sets the film's characteristics until it is reheated: this causes it to shrink back toward its initial dimensions.
Prior to orientation, the molecules of a sheet or tube are randomly intertwined like a bowl of spaghetti. The molecules are coiled and twisted and have no particular alignment. However when a draw force is imposed, the amorphous regions of the chains are straightened and aligned to the direction of orientation. By applying proper cooling, the molecules will be frozen in this state until sufficient heat energy is applied to allow the chains to shrink back. One can visualize this phenomenon by stretching a rubber band and dipping it into liquid nitrogen so as to freeze in the stretched state. The band will remain in this state as long as it is kept at sufficiently cold temperatures. However, when enough heat energy is applied, the rubber band will shrink back to its original relaxed state.