Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Coating of fillers

Fig. 3 a,b. Coating of filler particles a desired uniform surface layer b incomplete layer due to undesirable formation of a separate phase (either the neat coating agent or a product ol reaction with the filler material)... [Pg.80]

Flat coat n. Coat of filler (British) also incorrectly used when meaning prime coat under enamel. The preferred term is enamel un-dercoater. An intermediate coat of paint used as a base for a topcoat. [Pg.415]

Stearic acid. The effect of coating on crystallization depends on the number of layers deposited on the filler surface. Figure 7.2 shows the effect of excessive coating of filler surface. The nucleation of the PP lamellae is accomplished by the deposition of the first stem of lamellae on a smooth surface of the monolayer coating. The nucleation efficiency is diminished if there is an excess amount of stearic acid (absence of the smooth surface). It should be also noted that agglomeration of particles will diminish the nmnber of nuclei. Agglomeration can be caused by the lack of coating or the excessive amoimt of coated filler in formulation. [Pg.90]

In elastomers the effects of stearic acid coating of fillers appear mnch more dramatic in solution polymerised polymers than in emnlsion ones. As shown by Rothon, this is dne to the presence of large amounts of residnal snrfactants in the emulsion polymerised polymer [29]. These probably adsorb on the filler snrface, prodncing effects similar to stearic acid. In the absence of these competing effects, stearic acid reduces viscosity but also reduces the filler polymer interaction, resnlting in decreased bound rubber and... [Pg.172]

Coatings of filler between polymer and metal surfaces prevented the melting polymer from wetting the barrel and screw surfaces. [Pg.232]

Vulcanization accelerator systems, based on rub-ber-sulfur-organic accelerator, need activators, e.g., ZnO and ->stearic acid or Zn-stearate (- metallic soaps). - Fatty acids also improve processability. They may be already contained in synthetic rubbers, where their salts are used as - polymerization additive similar to the use of the salts of dis-proportionated rosin acid (- rosin), > ch impart improved tackiness to the rubber compound. Another example of product combination is the coating of fillers with - stearic acid to improve distribution. [Pg.247]

Deposition rates using this process are limited by the fact that each electrode contains a finite amount of filler metal. The time required both to change electrodes and to remove the slag coating between each weld pass lowers the overall productivity of the process. [Pg.342]

Although the use of simple diluents and adulterants almost certainly predates recorded history, the use of fillers to modify the properties of a composition can be traced as far back as eady Roman times, when artisans used ground marble in lime plaster, frescoes, and po22olanic mortar. The use of fillers in paper and paper coatings made its appearance in the mid-nineteenth century. Functional fillers, which introduce new properties into a composition rather than modify pre-existing properties, were commercially developed eady in the twentieth century when Goodrich added carbon black to mbber and Baekeland formulated phenol— formaldehyde plastics with wood dour. [Pg.366]

For wear resistance and low friction, coatings of PTFE or M0S2 generally have been satisfactory. Use of low thermal expansion filler in PTFE helps minimise cracking and loss of adhesion from metal substrates with their lower coefficients of expansion. [Pg.253]

One way of improving the adhesion between polymer and filler is to improve the level of wetting of the filler by the polymer. One approach, which has been used for many years, is to coat the filler with an additive that may be considered to have two active parts. One part is compatible with the filler, the other with the polymer. Probably the best known example is the coating of calcium carbonate with stearic acid. Such coated or activated whitings have been used particularly with hydrocarbon rubbers. It is generally believed that the polar end attaches itself to the filler particle whilst the aliphatic hydrocarbon end is compatible with the rubbery matrix. In a similar manner clays have been treated with amines. [Pg.128]

For electrical insulation china clay is commonly employed whilst various calcium carbonates (whiting, ground limestone, precipitated calcium carbonate, and coated calcium carbonate) are used for general purpose work. Also occasionally employed are talc, light magnesium carbonate, barytes (barium sulphate) and the silicas and silicates. For flooring applications asbestos has been an important filler. The effect of fillers on some properties of plasticised PVC are shown in Figure 12.21 (a-d). [Pg.338]

Solutions of the two recipes were blended in varying proportions to provide tie coats of continuously varying composition. The patent shows an example of eight plies or layers of graded composition between the rubber and the metal substrate. Because of the high fraction of reactive filler, the material closest to the metal substrate would be the most rigid and polar. The stiffness and polarity... [Pg.451]

The PVC is simply P /Vf and is determined by the volume of filler added to the formulation. The CPVC occurs when the binder particles are close packed and Vv = 0. At the CPVC, there is Just enough binder to coat all of the filler particles and the substrate with at least monomolecular layer of binder, and fill the interstices between particles. [Pg.456]

In the coating of continuous metal coils, reverse roller coating is often used. In this technique the web is moving counter to the application roller direction, so that the paint is partly wiped off by the moving coil. Shear leads to better flowout. Another type of reverse roller coating is used for the application of stiff paste fillers to chipboard. Application is by forward roller, but this is immediately followed by a reverse roller, which presses the filler into the board and doctors it smooth. [Pg.624]

It must be appreciated that there is an optimum percentage of filler which imparts to a coating the required melting point and toughness beyond this point application becomes more difficult and watertightness may be impaired. [Pg.662]

The authors of [317] investigated compositions based on PS, PMMA and styrene-acrylonitrile copolymer grafted to various fillers and found that it was possible, in this manner, to obtain particles with a grafted polymeric coating of sufficiently homogeneous thickness. [Pg.46]

The authors of [210] used the measured enthalpy values (AH) to compare the compatibility of fillers coated with different materials with the base PVC by the procedure described elsewhere [99]. The results are given in Table 14. [Pg.51]

From the table it is seen that the enhanced energy interactions between the polymeric coat of the filler and the matrix does not always entail an upgraded complex of physico-mechanical characteristics of the composite. The authors of [210] have advanced an opinion that the enhanced filler-matrix interaction prevents formation of labile bonds between the two and hinders the relaxation processes at the interphases. [Pg.51]

Note that the variation of the enthalpy of filler interaction with the coat (dH) is fully determined by dH since AHj and AH2 remain practically constant. [Pg.52]


See other pages where Coating of fillers is mentioned: [Pg.523]    [Pg.397]    [Pg.591]    [Pg.404]    [Pg.231]    [Pg.285]    [Pg.523]    [Pg.397]    [Pg.591]    [Pg.404]    [Pg.231]    [Pg.285]    [Pg.370]    [Pg.449]    [Pg.289]    [Pg.519]    [Pg.11]    [Pg.305]    [Pg.6]    [Pg.8]    [Pg.38]    [Pg.338]    [Pg.322]    [Pg.356]    [Pg.356]    [Pg.357]    [Pg.154]    [Pg.632]    [Pg.820]    [Pg.934]    [Pg.40]    [Pg.43]    [Pg.43]    [Pg.127]    [Pg.20]   
See also in sourсe #XX -- [ Pg.31 ]




SEARCH



Fillers coating

© 2024 chempedia.info