Bonding to plastic

Spray 0.1 ohm per square foot hard, dense coating. mechanical bonding to plastic special applications equipment required requires special applicator safety procedures for dust and fumes warps thermoplastics not suitable for thin-walled designs not field repairable. 

Acrylics offer some unique capabilities to bond to plastics without surface priming. They are also very good gap filling materials which makes their use preferable to solvent welding in many cases. The markets served include the recreational and industrial areas. Uses in the area of plastic appliances and other plastic molded devices are also known to exist. 

Sintered silicon carbide bonded to plastic laminate substrates reinforced with glass or Kevlar fabrics can be used as ceramic armor to defeat armor piercing projectiles [287]. 

The basic requirements for a good bond to plastic substrates are surface cleanliness, wetting of the surface by the adhesive, solidification of the adhesive, and proper selection of adhesive and joint design. These requirements are briefly defined here and then more thoroughly discussed in following sections. 

It is estimated that about one and a half million tonnes of filler undergoes smface treatment with a coupling agent to improve bonding to plastics. Some are coated for a different reason, i.e., to improve dispersion. 

A two component room temperature curing methacrylate adhesive offering an excellent bond to plastics, composites and certain metals. 

Table 1.12 Rubbers, vulcanisation bonded to plastics - systems and techniques ...

A further topic not mentioned here is the bonding of silicone on plastic inserts or monlded preforms, the snrface of which has been plasma treated. Another less important technology is the necessity of priming the mould with a release coating, e.g.. Teflon. These two techniques imply additional production steps and are therefore less relevant for the fntnre of silicone bonding to plastics. 

Aqueous emulsions of polymeric compounds, e.g., homopolymers of vinyl acetate and vinyl propionate, vinyl acetate copoljmiers with ethylene or maleic esters polyacrylic esters, styrene copolymers. Uses paper, wood, also bonding to plastics. 

The sandwich construction method mentioned above involves joining metals to other materials by bonding. Further examples include the bonding of brake linings (phenolic adhesives) and compound materials in ski manufacture, where aluminum is bonded to plastics, wood, etc. (phenolic and epoxy adhesives). Highly alloyed steels, beryllium and titanium alloys, and other special metals can be bonded with adhesives (e.g., polyi-mides, polybenzimidazoles) that have comparable high-temperature resistance. 

VMF415 Flexible, tough, noncrystalline adhesive. Excellent bonds to plastic films, PET (Mylar), vinyl. 180 220 2,360 Slow 5 C 160X... 

There are three basic forms of abrasives grit (loose, granular, or powdered particles) bonded materials (particles are bonded iato wheels, segments, or stick shapes) and coated materials (particles are bonded to paper, plastic, cloth, or metal). 

In coextmsion, two or more plastic melts from different extmders are combined into a single die in which the melts are joined. Coextmsion permits precise, small quantities of plastic materials to be intimately bonded to each other. 

In a variant of the horizontal form/fill/seal operation, the material, moving in a horizontal direction, is folded on itself vertically. Vertical sections of the two faces are heat-sealed to each other to form a pouch, which may then be filled. The pouch, usually made from film or paper bonded to aluminum foil plus a plastic laminant and heat sealant, is closed by a heat seal. This type of pouch gives high moisture and oxygen protection and is used for moisture-and flavor-sensitive condiments and beverage mixes. 

Covers for the battery designs in Figures 1 and 2 are typically molded from materials identical to that of the respective case, and vent plugs are frequentiy made of molded polypropylene. Other combinations are possible, eg, containers molded of polyethylene or polypropylene may be mated with covers of high impact mbber for use in industrial batteries. After the cover is fitted over the terminal post, it is sealed onto the case. The cover is heat bonded to the case, if it is plastic it is sealed with an epoxy resin or other adhesive, if it is vulcanized mbber. Vent caps are usually inserted into the cover s acid fiU holes to faciHtate water addition and safety vent gasses, except for nonaccessible maintenance-free or recombinant batteries. In nonaccessible batteries, the vent is fabricated as part of the cover. 

Plastic laminated sheets produced in 1913 led to the formation of the Formica Products Company and the commercial introduction, in 1931, of decorative laminates consisting of a urea—formaldehyde surface on an unrefined (kraft) paper core impregnated with phenoHc resin and compressed and heated between poHshed steel platens (8,10). The decorative surface laminates are usually about 1.6 mm thick and bonded to wood (a natural composite), plywood (another laminate), or particle board (a particulate composite). Since 1937, the surface layer of most decorative laminates has been fabricated with melamine—formaldehyde, which can be prepared with mineral fiUers, thus offering improved heat and moisture resistance and allowing a wide range of decorative effects (10,11). 

ABS plastic, a polymer consisting of polybutadiene spheroids is dispersed in a continuous phase of poly(styrene—acrylonitrile). The chromic acid attacks the polybutadiene at a much higher rate than the continuous phase. This gives an excellent microroughened surface with superior metal-to-plastic bond strength. A typical recommended formulation consists of 20 vol % sulfuric acid, 420 g/L chromic acid, and 0.1—1.0% of a fluorocarbon wetting agent. The plastic is treated with this formulation for 6—10 min at 60—65°C. 

Current usage is almost entirely associated with the good adhesion to aluminium. Specific applications include the bonding of aluminium foil to plastics films, as the adhesive layer between aluminium foil and polyethylene in multilayer extrusion-laminated non-lead toothpaste tubes and in coated aluminium foil pouches. Grades have more recently become available for manufacture by blown film processes designed for use in skin packaging applications. Such materials are said to comply with FDA regulations. 

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