Heat sealing property

Oriented polypropylene film has exceUent water-vapor barrier but poor gas barrier properties exceUent clarity, or opacity in newer forms and good heat-seal properties in packagiag appHcations. 

LLDPE with narrow molecular weight distribution exhibits a lower, a sharper melting point [3], better hot tack and heat seal properties as well as higher clarity and better impact resistance (Fig. 3), tensile strength (Fig. 4) [11], and lower levels of alkane-soluble components. The most distinguishing characteristic of metallocene-based LLDPEs is that they are not restricted by the current immutable property relationships that are... 

Packaging of meat, poultry and ice Good heat sealing properties... 

Low density poly(ethylene) (LDPE) may have unsatisfactory heat seal properties, as they often do not provide sufficient adhesion between the sealing layers to result in a good adhesive seal for a package. Efforts to improve the heat seal characteristics of LDPE by blending them with other materials, such as ethylene copolymers with methacrylic acid or acrylic acid, have not had universal success. 

The fact that foil has no heat seal properties initially limited expansion of foil usage (until plastic heat sealants became more readily available). Early heat sealants included waxes and microcrystalline waxes, either on their own or as coated or... 

Polyolefine films, mostly manufactured from polyethylene (PE), are most extensively used in anticorrosion techniques [8,12-20]. They are characterized by elasticity, low water and vapor permeability, mechanical strength, frost-resistance, inertness, perfect heat-sealing properties and non-toxicity. 

The introduction of metallocene catalysts has permitted new variants of LLDPE to be produced, with much improved ability to tailor properties to end-use requirements. LLDPEs that incorporate higher a-olefins as co-monomers have much improved heat seal properties, for instance. These new polymers are likely to further displace LDPE and result in even greater ability to downgauge films in both LDPE and LLDPE applications. These same catalyst systems are likely to also permit source reduction through downgauging in HDPE, PP, and other applications. 

Cellophane is used as a general protective wrapping material. Because of its good electrical properties, it is used in wire and cable construction and other electrical products. It also functions as a separator, barrier, or release film in plastic molding and lamination. To make it moisture proof, most of the cellophane film is coated with a lacquer composed of nitrocellulose, plasticizers, resins, and waxes. This coating can also give the cellophane film a heat-sealing property. 

May be used in cellophane coatings to improve heat-seal properties, without affecting color and clarity of the film. 

Common resins in use are rosin esters, such as ester gum, which is used for its low cost maleic resin, used in wood finishes for its good sanding properties and alkyds, employed for their good resistance and durability. Alkyds modified with coconut oil are often used these may be ftirther modified with other resins, such as terpenes, for good heat-sealing properties and phenolics, for good water resistance. 

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