Plastic to metal

The CLTE is an important consideration if dissimilar materials like one plastic to another or a plastic to metal and so forth that are to be assembled where material expansion or contraction is restricted. The CLTE is influenced by the type of plastic (liquid crystal, for example) and RP (particularly the glass fiber content and its orientation). It is especially important if the temperature range includes a thermal transition such as Tg. Normally, all this activity with dimensional changes is available from material suppliers. 

Adding or changing a child-resistant closure, changing from a metal to plastic screw cap, or changing from a plastic to metal screw cap. 

Use Ester exchange reactions heat-resistant paints (up to 500C) improving adhesion of paints, rubber, and plastics to metal surfaces cross-linking agent condensation catalyst. 

The diffusion bonding method described in Section 9.2.5 cannot be applied to the bonding of plastics to metals, since the metal surfaces are not swellable by means of organic solvents. Bonded joints are only possible after an adequate surface treatment with the known reactive adhesives. 

Urethane structural adhesives have been very popular for bonding of plastics to plastics and plastics to metal by the transportation industry. As an example, more than 90% of the bonds in Fords experimental graphite car were urethane adhesives rather than rivets or welds. Urethane structural adhesives have been used by the transportation industry since 1969. It is estimated that 5 million pounds of urethane structural adhesives were used in the transportation industry in the United States in 1979. Some of the advantages of urethane adhesives as used by the transportation industry are shown in Table IX. 

Versatility is a valuable asset. Urethanes can be used to bond a variety of plastics to plastics and plastics to metal. 

Adding or changing a child-resistant closure, changing from a metal to plastic screw cap, or changing from a plastic to metal screw cap Changing from one plastic container to another of the same type of plastic (e.g., high-density polyethylene container to another high-den-sity polyethylene container)... 

The interfacial energy Si>2 rises with increasing dissimilarity of materials 1 and 2 with regard to the type of atom, atomic spacing and bonding character. Consequently, S >2 and therefore the specific adhesive force fad decreases in the following sequence a) same materials, b) solid-solution formers, c) immiscible materials with different types of bonding. A plastic to metal contact provides an example of this last combination. 

Haberer, C., Adhesive Bonding of Plastics to Metal in the Automotive Industry, Science and Technology, Industry-University Short Course Program, CEI Europe, 1984, Chap. 11. 

These can be either (a) common film structures (which can be either in the common monolayer or in series of multilayered-coextruded film types) or, (b) hybrids (hybrid structures can be of plastic-to-metal or plastic-to-paper type, i.e., multilayer films with paper and with metal foils, protective coating for metals, and so on). 

Storage Readily hydrolyzed handle and store under nitrogen Uses Catalyst for esterification and olefin polymerization adhesion of paints, rubber, and plastics to metals condensation catalyst surf, modifier for coatings, cosmetics, electronics, films, glass, graphic arts, metals, petrol, prods., plastics in food-pkg. adhesives Regulatory FDA 21CFR 175.105... 

Bonding Plastic to Metal for High Strength at Low Temperatures (4) 123... 

Calculating stress is done by multiplying the strain by the tensile modulus of the material at its operating temperature. With a plastic-to-metal attachment, a temperature change causes both to expand. A plastic will usually apply an insignificant load to a metal, but considerable stress will occur in the plastic. (Remember that there are plastics with a CLTE equal to or less than that of steel and aluminum and other such materials.) In this particular metal-to-plastic attachment example, the approximate thermal stress, ar, in the plastic is ut = oim oip)Ep T... 

In many assemblies the clearances around fasteners, the degrees of failure or yield in adhesives, and warpage or creep will tend to relieve the thermal stress. As with metal-to-metal attachments having different CLTEs, proper design allows for such temperature changes, especially with large parts that might be subject to wide temperature variations (see Fig. 5-57). The relative motion, A rel, between two attachment points of joined plastic-to-metal parts in which motion is allowed results in... 

Dorn, L., et al. Design of Plastics to Metal Adhesive Joints. Kunststoffe, pp. 3-6, July... 

The ability to join different materials such as plastic to metal, glass, or mbber. 

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