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A release liner or release paper is a paper or plastic-based film sheet (usually applied during the manufacturing process) used to prevent a sticky surface from prematurely adhering. It is coated on one or both sides with a release agent, which provides a release effect against any type of a sticky material such as an adhesive or a mastic. Release liners are available in different colors, with or without printing under the low surface energy coating or on the backside of the liner. Release is separation of the liner from a sticky material; liner is the carrier for the release agent.
Globally there are between 400 and 500 companies involved in making or dealing with release liner products on an industrial scale. In general there are two types of companies which are manufacturing release liner.
Commercial coating companies deal with a lot of different end uses of this industry. They provide unique solutions to their customers, based on a wide variety of substrates and an endless combination of release agents with specialized properties. Commercial coaters usually do not make finished products, just the release liner itself and then their customers will coat a sticky material on this liner and then apply the end product to it.
An in-house producer makes the release liner and uses it internally to manufacture the final product. In-house producers are typically focused on a very narrow range of products e.g. labels or tapes. They use a limited amount of substrates and release materials, which are specialized for their end applications.
As liner material, the industry is using a wide variety of so-called substrates, which are the carrier materials of the release agent and which is needed to transport a sticky material from the manufacturer to an industrial or private end user. Typical liner materials are:
Plastic films in general are made out of plastic resins by a plastics extrusion process and can be made out of one single type of plastic material, a blend of different plastic materials or multilayered coextrusions. Providing them with unique and adjusted features for the application that they are targeted for.
Commonly used release agents for release liner can be crosslinkable silicone, other coatings, and materials that have a low surface energy. [1]
There are probably hundreds of different applications, where release liner materials are being used. Such as
Adhesive, also known as glue, cement, mucilage, or paste, is any non-metallic substance applied to one or both surfaces of two separate items that binds them together and resists their separation.
Cellophane is a thin, transparent sheet made of regenerated cellulose. Its low permeability to air, oils, greases, bacteria, and liquid water makes it useful for food packaging. Cellophane is highly permeable to water vapour, but may be coated with nitrocellulose lacquer to prevent this.
BoPET is a polyester film made from stretched polyethylene terephthalate (PET) and is used for its high tensile strength, chemical stability, dimensional stability, transparency, reflectivity when metallized, gas and moisture barrier properties, and electrical insulation. The film is "biaxially oriented", which means that the polymer chains are oriented parallel to the plane of the film, and therefore oriented in two axes. A variety of companies manufacture boPET and other polyester films under different brand names. In the UK and US, the best-known trade names are Mylar, Melinex, Lumirror and Hostaphan. It was the first biaxially oriented polymer to be manufactured on a mass commercial scale.
Epoxy is the family of basic components or cured end products of epoxy resins. Epoxy resins, also known as polyepoxides, are a class of reactive prepolymers and polymers which contain epoxide groups. The epoxide functional group is also collectively called epoxy. The IUPAC name for an epoxide group is an oxirane.
In materials science, a thermosetting polymer, often called a thermoset, is a polymer that is obtained by irreversibly hardening ("curing") a soft solid or viscous liquid prepolymer (resin). Curing is induced by heat or suitable radiation and may be promoted by high pressure or mixing with a catalyst. Heat is not necessarily applied externally, and is often generated by the reaction of the resin with a curing agent. Curing results in chemical reactions that create extensive cross-linking between polymer chains to produce an infusible and insoluble polymer network.
Lamination is the technique/process of manufacturing a material in multiple layers, so that the composite material achieves improved strength, stability, sound insulation, appearance, or other properties from the use of the differing materials, such as plastic. A laminate is a layered object or material assembled using heat, pressure, welding, or adhesives. Various coating machines, machine presses and calendering equipment are used.
A label is a piece of paper, plastic film, cloth, metal, or other material affixed to a container or product, on which is written or printed information or symbols about the product or item. Information printed directly on a container or article can also be considered labelling.
Powder coating is a type of coating that is applied as a free-flowing, dry powder. Unlike conventional liquid paint, which is delivered via an evaporating solvent, powder coating is typically applied electrostatically and then cured under heat or with ultraviolet light. The powder may be a thermoplastic or a thermosetting polymer. It is usually used to create a thick, tough finish that is more durable than conventional paint. Powder coating is mainly used for coating of metal objects, particularly those subject to rough use. Advancements in powder coating technology like UV-curable powder coatings allow for other materials such as plastics, composites, carbon fiber, and medium-density fibreboard (MDF) to be powder coated, as little heat or oven dwell time is required to process them.
Hot-melt adhesive (HMA), also known as hot glue, is a form of thermoplastic adhesive that is commonly sold as solid cylindrical sticks of various diameters designed to be applied using a hot glue gun. The gun uses a continuous-duty heating element to melt the plastic glue, which the user pushes through the gun either with a mechanical trigger mechanism on the gun, or with direct finger pressure. The glue squeezed out of the heated nozzle is initially hot enough to burn and even blister skin. The glue is sticky when hot, and solidifies in a few seconds to one minute. Hot-melt adhesives can also be applied by dipping or spraying, and are popular with hobbyists and crafters both for affixing and as an inexpensive alternative to resin casting.
A laminator is a device which laminates pieces or rolls of paper or card stock.
A countertop, also counter top, counter, benchtop, worktop or kitchen bench, bunker is a raised, firm, flat, and horizontal surface. They are built for work in kitchens or other food preparation areas, bathrooms or lavatories, and workrooms in general. The surface is frequently installed upon and supported by cabinets, positioned at an ergonomic height for the user and the particular task for which it is designed. A countertop may be constructed of various materials with different attributes of functionality, durability and aesthetics, and may have built-in appliances, or accessory items relative to the intended application.
In-mould labelling is the use of paper or plastic labels during the manufacturing of containers by blow molding, injection molding, or thermoforming processes. The label serves as the integral part of the final product, which is then delivered as pre-decorated item. Combining the decoration process with the moulding process cuts the total cost, but can increase the manufacturing time. The technology was first developed by Owens-Illinois in cooperation with Procter & Gamble to supply pre-labelled bottles that could be filled on the product filling line. This was first applied to Head & Shoulders shampoo bottles.
Pressure-sensitive adhesive is a type of nonreactive adhesive which forms a bond when pressure is applied to bond the adhesive with a surface. No solvent, water, or heat is needed to activate the adhesive. It is used in pressure-sensitive tapes, labels, glue dots, stickers, sticky note pads, automobile trim, and a wide variety of other products.
Coated paper is paper that has been coated by a mixture of materials or a polymer to impart certain qualities to the paper, including weight, surface gloss, smoothness, or reduced ink absorbency. Various materials, including kaolinite, calcium carbonate, bentonite, and talc, can be used to coat paper for high-quality printing used in the packaging industry and in magazines.
A release agent is a chemical used to prevent other materials from bonding to surfaces. Release agents aid in processes involving mold release, die-cast release, plastic release, adhesive release, and tire and web release. Release agents are one of many additives used in the production of plastics.
Adhesive tape is one of many varieties of backing materials coated with an adhesive. Several types of adhesives can be used.
Plastic film is a thin continuous polymeric material. Thicker plastic material is often called a "sheet". These thin plastic membranes are used to separate areas or volumes, to hold items, to act as barriers, or as printable surfaces.
Pressure-sensitive tape or pressure-sensitive adhesive tape is an adhesive tape that will stick with application of pressure, without the need for a solvent or heat for activation. It is known also in various countries as self-stick tape, sticky tape, or just adhesive tape and tape, as well as genericized trademarks, such as Sellotape, Durex (tape), Scotch tape, etc.
The chemistry of pressure-sensitive adhesives describes the chemical science associated with pressure-sensitive adhesives (PSA). PSA tapes and labels have become an important part of everyday life. These rely on adhesive material affixed to a backing such as paper or plastic film.
Self-adhesive plastic sheet, known in the United Kingdom as sticky-backed plastic, is wide plastic sheet or film with an adhesive layer on one side, used as a surface coating for decorative purposes. It is typically smooth and shiny, but can also come in textured varieties, in which case it can sometimes be used as a cheap alternative to veneer. The plastic is often PVC. The sheeting is typically sold with a removable paper release liner to prevent it from adhering prematurely.