Fluorine-based adhesives

Since it was observed that fluorine contamination was a possibility and had potentially detrimental effects as described in Chapter 10, the excellent primer adhesion achieved with Tfs/(Ar) and Tcs/(Ar), shown in Table 31.3, has significant importance in the practical application of the plasma technique without any of the potentially deleterious effects of fluorine-based systems. Argon plasma treatments on both flow system TMS (Tfs) and closed system TMS (Tcs) polymers were then investigated as an additional system modification that could provide strong adhesion without the incorporation of fluorine-containing monomers in the quest to produce chromate-free coatings systems. 

Fluorine-based adhesive with low Young s modulus and high gasoline resistance to be used to bond the glass base to the case. 

Today it is claimed that the surface fluorination of polymers using F2 gas mixtures enhances a wide range of properties, e.g., low permeability to nonpolar liquids4 improved permselectivity,5-6 excellent wettability and adhesion,7 low friction coefficient (especially for elastomers),8 and chemical inertness.9 Obviously, these properties depend on the chemical composition ofthe fluorinated layer, which in turn is determined by the chemical structure ofthe base polymer, the composition of the F2 gas mixture, and the fluorination parameters. 

It is known that fluorinated HDPE containers are highly suitable for the packaging of numerous other products such as adhesive systems, oil-based paints, polishes, hand cleaners, and hydrocarbon solvents.12... 

Another benefit of the fluorinated layer is its excellent adhesion properties. Printing (including water-based inks) and labels will normally adhere tenanciously to a fluorinated layer. In some cases it is even possible to fluorinate printed containers without discoloration ofthe printing. In these cases the printing will be far more insoluble to a large spectrum of solvents and will then only be removed with difficulty. 

The conclusion that might be drawn from published results,7,29 that adhesive/coating systems adhere just as well to fluorinated and oxfluorinated surfaces, is not supported by our experience based on activation conditions normally encountered in commercial postfluorination plants. 

Adhesive strength may possibly be predicted by using the acid-base theory.39 We have already found linear relationships between adhesive strength and either the acid or base component of the fluorinated surface.40... 

If a single metal film is deposited on an oxide, the sheet resistance measurement results can by easily interpreted and converted to the thickness. In practice, however, this is not usually the case. For example, in W CVD, the tungsten is not directly deposited on oxide due to high residual stress and unreliable adhesion. A titanium (Ti) layer must be first deposited as a glue layer. In addition, to prevent the fluorine in the CVD-precursor WFg from directly reacting with Ti (a strong catalytic reaction will occur), a barrier layer of titanium nitride (TiN) must be deposited on top of the Ti. As a result, we have a trilayer film of W on TiN on Ti on oxide, as shown schematically in Fig. 21. This poses some problems in accuracy in the four-point probe measurements. Based on the resistivities in Table VI, the... 

In optical applications, in addition to optical liber claddings, special optical adhesives matching refractive indexes of optical glass components based on fluorinated epoxyacrylates and epoxymethacrylates are used.29 Fluoroalkyl methacrylates are frequently incorporated as comonomers with siloxanyl methacrylates into contact lenses for the improvement of oxygen permeability.31... 

Fluorinated surfactants (or fluorosurfactants, i.e., surfactants with hydrophobic tails comprising a fluorocarbon moiety) provide an alternative means of achieving extremely stable PFC emulsions, as they can provide very low PFC/water interfacial tensions [cr , another factor in Eq. (2)]. d s yet, this option has not been developed, in part because of the added cost involved in the evaluation for approval of a novel active excipient. A further means of effectively increasing the stability of EYP-based PFC emulsion consists of supplementing standard phospholipids with mixed fluorocarbon-hydrocarbon diblock compounds, such as 14 or 15. Such diblocks, which have fluorophilic-lipophilic amphiphilic properties, are expected to improve the adhesion of the phospholipid film onto the PFC droplet. 

The good properties of poly(ester-imide) based varnishes led to patents where this type of product is claimed for use as industrial coatings. Formulated with fluorinated resins, films with good adhesion and low friction coefficients were obtained [227-229]. Good adhesion [230] and good corrosion resistance combined with excellent long term temperature resistance were also claimed [231],... 

The article, which is usually in the form of an impregnated fabric, is laid-up on a mold or a base plate (Figure 6.65 and 6.66) which defines the surface shape of the article. A release agent is applied to the mold surface to prevent adhesion of the part to the mold. A release film, such as a fluoropol5mier typically a fluorinated ethylene propylene copol5mier or a glass fabric coated with polytetrafluoroethylene is often the next layer. Other films such as nylon or polyester can be used where release is less demanding such as lower cure temperature resins. 

PAI with a higher refractive index than conventional fluorinated PI consist of chlorinated monomers. When using such a PAI type as a material for the core of an optical fiber, the selection range on the material for cladding becomes more wide. In addition, the coating performance and the adhesiveness to a substrate are improved compared to a conventional PI. Imide containing monomers based on 3,5,6-trichloro-4-chloroformyl phthalic acid anhydride have been proposed for optical applications, since the refractive index is sufficiently high. ... 

The addition of surfactant to the adhesive changes the surface properties of the polymers, and consequently changes the wetting of the solid surface. As Fig. 5.1 shows, the addition of 1% OP-10 or of the fluorinated alcohol CF3(CF2)CH20H to an adhesive based on a 40% solution of PBMA in MMA decreases the interfadal angle for wetting of the steel siuface by the adhesive from 72° to 30-50°. 

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