Page 163 - Handbook of Adhesion Promoters

156 Selection of Adhesion Promoters for Different

8.14 POLYETHYLENE

A good selection of commercial additives is available for adhesion promotion of polyeth-
ylene, including Amplify GR 204 & 205, Dow Corning Z-6518, Dynasylan 1198, 6490,
and VTEO, Eastman CP 153-2, Fusabond (six different grades), Geniosil XL 12, Resalloy
060, and Tyzor TPT & AA-105.
The performance of polyethylene/clay/silver nanocomposites depends on the proper-
1
ties of the filler-matrix interface. Maleic anhydride, itaconic acid, and 2-[2-(dimethylam-
ine)-ethoxy] ethanol were used to functionalize polyethylene by grafting during melt
1
mixing, followed by wet coating with silver. The silver-coated compatibilizers were
mixed with polyethylene and modified clay. All the 2-[2-(dimethylamine)-ethoxy] ethanol
1
compatibilized nanocomposites had better clay and silver dispersion and exfoliation.
Low free surface energy of polyethylene prevents good wettability of by adhesives
2
or paints. Blending with thermoplastic polyurethane (25-35 wt%) significantly improves
2
adhesion between blend and polyurethane paint. During painting and drying step, poly-
urethane chains from the paint diffuse into the blend and entangle with TPU in the blend
2
(see Figure 7.4 and discussion). The entanglements generate a physical link that provides
adhesion. 2
Sawdust-reinforced linear low-density polyethylene composites were prepared by
using ethylene-vinyl alcohol copolymer as an adhesion promoter to improve mechanical
3
3
strength. The optimum vinyl alcohol content was evaluated. The sawdust-LLDPE com-
posites prepared with EVAl containing 15 mol% VA showed the maximum yield stress
3
and modulus due to a good adhesion between sawdust and the matrix polymer. Hydrogen
3
bonding interaction between sawdust and EVAl was detected by FTIR spectra.
Vinyltrimethoxysilane was used for grafting silane functionality on polyethylene to
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be used later for moisture crosslinking with substrates.
15% LLDPE modified with 10% maleic acid anhydride was found to be optimal
addition to LLDPE composites containing 20% phlogopite to improve adhesion between
5
filler and matrix and thus improve the mechanical performance of the composite.
The adhesion promoter (an olefin-based polymer having at least one amine-contain-
ing compound) was used in a curable coating composition that was applied to olefinic sub-
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strates such as thermoplastic polyolefin. Adhesion additives are often used as
components in primer surfacers, or other intermediate coating compositions, to promote
adhesion between a substrate and a topcoat system for an automobile, such as a topcoat
6
system including a flexible basecoat and flexible clearcoat. The applied adhesion pro-
moter may be either coated “wet on wet” with one or more coating compositions and then
all layers cured together, or the adhesion promoter layer may be partially or fully cured
6
before being coated with any additional coating layers. Curing under any of these condi-
6
tions allows subsequent coating layer(s) to be applied electrostatically. Adhesion pro-
moter with 1-2 wt% dimethylaminoethanol or aminomethylpropanol lower paint
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resistivity below 1.5 Mohms.
The adhesion promoter for digital printing on polyethylene is selected from the
group consisting of an aliphatic polyurethane dispersion, a hydrogenated hydrocarbon
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rosin or rosin ester dispersion, and an amorphous acrylic polymer dispersion.