Polyethylene film lamination

Lamination Inks. This class of ink is a specialized group. In addition to conforming to the constraints described for flexo and gravure inks, these inks must not interfere with the bond formed when two or more films, eg, polypropylene and polyethylene, are joined with the use of an adhesive in order to obtain a stmcture that provides resistance properties not found in a single film. Laminations are commonly used for food applications such as candy and food wrappers. Resins used to make this type of ink caimot, therefore, exhibit any tendency to retain solvent vapor after the print has dried. Residual solvent would contaminate the packaged product making the product unsalable. 

Self-curing butyl adhesives can be used for laminating polyethylene film and for flocking adhesives. One of the most important applications is the use of BR as curing, solvent-dispersed and contact-grade for roof manufacturing on industrial buildings. 

Laminated tapes In more general use now than pressure sensitive tapes are tapes consisting of polyvinyl chloride or polyethylene films in conjunction with butyl rubber. These tapes are applied with an adhesive butyl rubber primer. Thicknesses of up to 0-75 mm are in use and loose protective outer wraps of p.v.c. or polyethylene sheet are commonly applied. Tape quality control is exercised with reference to ASTM standard test methods and may include water vapour transmission rate and elongation. 

Lower-density E-plastomers have found alternate use in cast film processes to make elastic film laminates with good breathability which contain laminates of liquid impermeable extensible polymeric films with extensible-thermoplastic-polymer-fiber nonwovens and nonwoven webs of polyethylene-elastomer fibers as the intermediate layers. The development relates to a breathable film including an E-plastomer and filler that contributes to pore formation after fabrication and distension of the film. The method and extent of distension is designed to produce a breathable film by stretching the film to form micropores by separation of the film of the E-plastomer from the particulate solids. This film is useful for manufacture of absorbent personal-care articles, such as disposable diapers and sanitary napkins and medical garments. In detail, these constructions comprise a liquid impermeable extensible film comprising polyolefins. The outer layer contains extensible-thermoplastic-polymer-fiber nonwovens, and an elastic intermediate layer contains nonwoven webs of fiber E-plastomers. The intermediate layer is bonded to the film layer and the outer... 

Subramaniam, 1988]. Hydrochlorination, usually carried out at about 10°C, proceeds by electrophilic addition to give the Markownikoff product with chlorine on the tertiary carbon (Eq. 9-33) [Golub and Heller, 1964 Tran and Prud homme, 1977]. Some cyclization of the intermediate carbocation (XXVI) also takes place (Sec. 9-7). The product, referred to as rubber hydrochloride, has low permeability to water vapor and is resistant to many aqueous solutions (hut not bases or oxidizing acids). Applications include packaging film laminates with metal foils, paper, and cellulose films, although it has been largely replaced by cheaper packaging materials such as polyethylene. 

So far, emphasis has been placed on the treatment of polyolefins to improve printability, but the same treatments affect also other processes. As an example, while an untreated polyethylene surface will not retain an adhesive the treated and modified surfaces are receptive to adhesives. A field of increasing importance for packaging is the production of laminates of film with other materials and, as examples, suitably pre-treated polyethylene film can be bonded securely to substrates such as cellulose or polyester films and aluminium foil, using standard adhesives, whereas this cannot be achieved without pre-treatment. 

Corrugated boxboard is made by gluing sheets of linerboard to each side of a fluted sheet of the corrugating medium. Papers for packing may be laminated to polyethylene film or aluminum foil, or coated with waxes and hot-melt resins. The printing and bag- and box-making industries depend on the production of many mills that produce the several hundred grades of paper used in the United States, and each user may require special paper characteristics to match its process. 

Lamination Shop. This shop has four restorers who keep an Arbee machine in constant use, laminating material that does not lend itself to other methods of repair. Polyethylene film and Japanese tissue are used to make a sandwich for the damaged artifact in a process that uses application of heat, then pressure with metal rollers, to complete the cycle. 

Coated or laminated paper products represent a significant potential market for biodegradable polymers. At present, packaging such as hamburger wrapping and disposable cups, are extrusion coated with low density polyethylene film that is resistant to biodegradation. This also restricts the biodegradation of the paper substrate since it acts as an impervious barrier. 

Films made with barrier polymers, e.g., polyamide (PA)/polyethylene (PE) laminates, ethylene vinyl acetate (EVA) copolymer/polyvinyl chloride (PVC)-polyvinylidene chloride (PVDC) copolymer laminates, and ionomer/ PA/EVA laminate films are used for vacuum packaging, particularly products like red meat. 

Nuts Polyethylene/aluminium/printing inks/polyester film laminate Polyethylene/aluminium/cartonboard container laminate printed on the external surface Polyethylene/aluminium/paper laminate with an uncoated metal base... 

Mitsubishi Polyethylene. [Mitsubishi Kasei] HOPE, LDPE, LLDPE resins for inj. and blow molding, extrusion, mondfilament stretched tape, pipe, film and oriented film, lamination. 

Sample Preparation. Polyethylene pellets were processed on a two-roll mill followed by pressing between clean aluminum sheets at 110°-125 °C for one minute. The resultant films were preoxidized to varying extents by initially exposing them in air to 5 Mrads of y-radiation from a C060 source followed by exposure to one atmosphere of oxygen gas in sealed vessels at 90°-100°C. The extent of oxidation was monitored by ir spectroscopy (see below). Two types of laminates were formed from 1.5 cm X 1.0 cm polyethylene films about 0.025 cm in thickness (a) a... 

Another interesting development of the wash-out imaging technique is Che photoresist film. This film is sandwiched between a polyethylene film as protective cover sheet and a polyester support. A machine is used for laminating Co copper, cooper-board materials, or other supports after the polyethylene film has been stripped off. After exposure the cover sheet is eliminated and... 

Natural rubber adhesive, or latex, is used in self-seal applications, where it makes use of its unique ability to bond only to itself with pressure. Applications include selfseal envelopes, press-to-seal cases, and cold-seal candy wraps. Natural rubber latex is also used in adhesives for lamination of polyethylene film to paper, such as in multiwall hags. 

Resin lamination should not be carried out at a temperature of less than 20C (68F). A catalyzed/promoted resin is heat-sensitive and catalyst levels should be adjusted to varying temperature as recommended by the manufacturer. With resin laminating, where space is limited, mold preparation such as releasing and gelcoating can be done in a tent made of polyethylene film (which can also be used as a warm area for curing resins in cold weather). 

A fairly recent development is the manufacture of cross-laminated unidirectionally oriented films which can be used for the manufacture of sacks. Rasmussen " invented this process in which films are spirally cut from unidirectionally stretched tubes and laminated by means of an adhesive. The orientation directions of both layers are perpendicular to each other and at an angle of approx. 45° to the longitudinal direction of the laminate. Sacks manufactured from cross-laminated high-density polyethylene film have very high strength, tear strength and puncture resistance and are sold under the trade name Valeron . 

---