Surface-treated kaolin

In another study, a highly impact-modified copolymer PP resin was extruded and then injection molded. The surface-treated kaolin doubled the flexural modulus... 

Kaolin also serves as functional filler in wire and cable insulation. As with other applications, surface-treated kaolin offers the best improvement in performance,... 

An additional evaluation [18] of the extension of rutile Ti02 by different fillers was conduded by assessing blister resistance in two types of liquid, thermosetting polyester resins (namely ortho- and ortho-neopentyl glycol (NPG). The performance of the filler/pigment portion of the cured polyester gel coat was compared after exposure to water at 65 °C for 1150 h (Table 13.12). Untreated kaolin provided better blister resistance than untreated talc or calcium carbonate. Vinylsilane surface-treated kaolin gave the best blister resistance, reducing the size and extent of blisters... 

Transbuk, Surface-treated kaolin, Engelhard Corp. 

Inks. Refined kaolin is a common ingredient in a large variety of printing inks (qv). In addition to extending the more expensive polymers present, ka olin also contributes to improved color strength, limits the penetration of the ink into the paper, controls rheology, and improves adhesion. Kaolin for this appHcation must usually be as white as possible and free from oversize particles. Surface treated clays are used to improve compatibiHty with oil-based ink. Clays can also be an ingredient in the newer water-based or uv-cured inks. 

Clays vary in price from only a few doUars per ton for common clay to > 0.25/kg for some of the specialty surface treated clays. For clays that are used in large quantities such as kaolins for paper coatings, transportation to the point of use may be the primary cost component. 

Surface-treating agent PVA as, 25 618 Surface treatment(s) kaolins, 6 679... 

Special surface modifications are available to further improve reinforcement. The objective of the surface treatment is to increase filler loading and/or improve physical properties without loss of rheological characteristics. A variety of surface-modified kaolins have been introduced including clays treated with silane, titanate, polyester, and metal hydroxide. Silane-treated kaolin is used in applications requiring maximum aging characteristics in the service environment. 

Thermo-optic grades - Optiwhite, Opti white MX, Optiwhite P, 30 P (see process discussion below) Burgess 2212, 2227 - calcinated kaolin surface treated with amino silane... 

Economic Aspects. The calcium carbonates (calcites, chalks, limestone powders, dolomites, precipitated calcium carbonates, and surface-treated carbonates) account for 80-90 % of the extenders used in Western Europe. In the Federal Republic of Germany calcium carbonates are more predominant than in the remainder of Western Europe (ca. 90%) calcites with a high degree of whiteness and a mean particle size of 2-5 pm are most widely used. Next follow talc, kaolins (with calcined kaolins), silica, barytes, and mica. 

Vlasova, N. N., Matkovskii, P. Y, Yenikolopyan, N. S., Papoyan, A. T, Vostorgov, B. Y, and Sergeyev, V. 1.1985. Effect of various factors on the kinetics of ethylene consumption during its polymerization on the surface of kaolin particles treated with organo-aluminum compounds. Polymer Science USSR 27 2380-2385. 

Clay n. Any naturally occurring sediment rich in hydrated silicates of aluminum, predominating in particles of colloidal or near-colloidal size. There are many types of clays and clay-like minerals. Those of particular interest to the plastics industry are varieties refined by nature and man to a state of good color and particle-size distribution, such as kaolin (China clay). They are used as fillers in epoxy and polyester resins, PVC compounds, and urethane foams. Calcined clays are those that have been heated to a high temperature to drive off the chemically bound water, sometimes also surface-treated to improve their chemical inertness and moisture resistance. They are used primarily in vinyl insulation. 

Kaolin deposits are cored and analyzed before mining to determine quality. Mined clays are then either wet or dry processed by air floatation or water fractionation. Surface-modified clays can be made by treating standard, delaminated, and calcinated grades with surface modifiers. The treatment can be performed by either the supplier or the end user. These surface modifiers include silane, titanate, polyester, and metal hydroxide. The objective of these surface treatments is to increase filler loadings and/or improve physical properties such as melt viscosity, thermal stability, and modulus without loss of physical characteristics. Electrical applications represent the largest use of surface-modified kaolin in plastics. 

Kaolin, surface treated Nylon Dimensional stabdity... 

US consumption of fine particle-sized calcium carbonates (which improve brightness and reduce absorption in a variety of polymer matrices) is expected to reach about 176 SOO tonnes by 2003. valued at US 38.6 million. Use of fine-particle kaolin and other clay-based fillers in plastics will total 57 600 tonnes, valued at US 21,7 million, and compounders and resin producers are expected to increase use of fine-particle and surface-treated alumina trihydrate by 6.2% per year, from about 30 800 tonnes in 1998 to 41 700 tonnes by 2003. 

FIGURE 8.9 (a) The normalized pore volume vs. pore diameter for composites subjected to slow heating from room temperature to 1000 °C during 2 h (b) Graph presents precisely differences in the characteristics for samples containing aluminum hydroxide (ALOH), surface treated montmorillonite (M-MMT) and calcined kaolin (C-KAO). 

Kaolin is primarily used in the rubber industry as a filler and is frequently used in the calcined form. It is being widely used in innerliner compound in the tubeless tire industry. Use of kaolin in glass fiber reinforced thermosets improves surface quality, reduces warpage, and lowers crack formation. Kaolin is used in polyvinyl chloride (PVC) wire coating because of its good electrical insulating properties. Surface-treated calcined kaolines are used for tire wheel cap made from polyamides (PA) and greenhouse films from LDPE [7[. 

Surface-treated clay - This is processed kaolin diat has been surface modified (e.g., with stearates or silanes) to improve compatibility with and performance in organic matrices. 

Data in Table 3 show that after high temperature treatment the alumina/kaolin base matrix retains, 32 % of its original surface area, while the silico-aluminate of reference retains 58 %. The experimental prototypes treated under the same conditions, in addition to having a considerably greater area, after being deactivated, appear to be more stable, since they retain 78% on the average of their original surface area. 

The effect of fillers on creep phenomena (essentially the inverse of stress relaxation) is also of interest a detailed study by Nielsen (1969b) of creep in filled polyethylene is illuminating. Kaolin and wollastonite were used as fillers, both treated with a silane coupling agent and untreated. A major aim was to discover whether the major effect of a filler is due to its effect on elastic modulus, or whether a filler also changes the viscoelastic nature of the system. As reported in previous work by others, the presence of a filler did in fact reduce the creep, the relative effect being nearly independent of the applied stress. The nature of the filler and the surface treatment were also found to be important. In experiments at a constant volume fraction (0.2), kaolin was more effective than wollastonite. Silane treatment of the filler surface tended to decrease creep, especially if the specimens had been soaked in water. 

Suzuki and Suga reported the use of clays as solid acids to support and activate metallocene catalysts for olefin polymerization. They were able to use much less alkylaluminmn cocatalyst relative to solution polymerization conditions. The clays were slurried with AlMeg in toluene, then treated with a solution containing zirconocene dichloride, II, and AIMeg. The metallocenium cation was presumed formed via abstraction of chloride and/or methyl ligands by acidic sites on the surface of the clay, and the low basicity of the clay smface was proposed to stabilize the coordinatively unsaturated cation. Propylene was copolymerized with 250 psi ethylene at 70°C. For acid-treated KIO montmorillonite, an activity of 3300 X 10 kg polymer/(g Zr h) was obtained. Catalysts based on vermiculite, kaolin, and synthetic hectorite all showed lower but still appreciable activities. In this brief report, the Al/Zr ratio was not specified, and the clay dispersion was not reported. 

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