Effect of zinc stearate

The effect of zinc stearate concentration on the melt flow of zinc, magnesium, and barium sulfonate-containing CR-2504 is shown in Figure 4. These results parallel those obtained with stearic acid plasticizer (cf. Table I). The zinc sulfonate EPDM responded most readily to zinc stearate plasticization. Although the melt flows of the magnesium and... 

Figure 4. Effect of zinc stearate on the melt index of metal sulfonate CR-2504 (base polymer—CR-2504 sulfonate content—33 meq/100...

The effect of zinc stearate concentration on the room temperature tensile properties of the zinc, barium, and magnesium ionomers is illustrated in Figure 5. Whereas stearic acid showed little or modest improve-... 

According to some authors, the ZnO and the stearic acid react with each other within the rubber compound during the vulcanization process and generate zinc stearate. The effect of zinc stearate as an activator for black filled SBR compounds with the sulphenamide accelerator TBBS has already been studied [52]. The authors of this work did not cite any other references on the topic. They examined the Zn stearate as an activator of the sulfur... 

Melt viscosity g s (c) Effect of zinc stearate on melt (xl0 ) viscosity (base polymer sulfo- Viscosity as melt index (3)... 

Solutions of different carboxylic acids (fiimaric acid [FA], maleic acid, acrylic acid, succinic acid, and malonic acid) in ethanol have been effectively used as primers to increase the adhesion of synthetic vulcanized SBRs. The increase in the adhesion properties of SBR treated with carboxylic acid is attributed to the elimination of zinc stearate moieties and the deposition of acid on the rubber which migrates into the solvent-borne polyurethane adhesive layer once the adhesive joint is formed. The nature of the carboxylic acid determines the rate of diffusion into the adhesive and the extent of rubber-adhesive interfacial interaction. 

Zhang and Xu [1993] blended EVAc and CPE (chlorinated-polyethylene) with PE (Table 11.9), because crosslinked PE has low flexibility for use as cable insulation. They mixed 30-70% HDPE with 70-30% EVAc or CPE, along with 0.5-1.0% of the antioxidant 1010 and 0.5-1.0% of zinc stearate in a SK-160B double roller mixer at 130-140°C. The blends so made were either hot-pressed into sheets or extruded into tubes, and irradiated with 1.5-MeV electrons to a dose of 100 kGy. Some properties of the irradiated blends and PE are compared in Table 11.21. As the data in this Table show, the flexibility and the elongation of the HDPE/EVAc and HDPE/CPE blends are better than those of the PE but their hardness and softening points are lower. The two blends also show the memory effect better than that shown by the PE. Moreover, the heat-shrunk tubes of the PE/EVAc and PE/CPE blends were more flexible than those of the heat-shmnk PE. 

It is typical for the mbber industry that the important inventions are manifested firstly in technologies with a practical aspect and only after that the research on their theoretical explanation gets developed. It is clear for each specialist from the field of mbber products that the content of the stearic acid and/or zinc stearate within the mbber compound contributes to easily release the article from the mold and the final product has a better appearance. With changes in the amounts of stearic acid or of zinc stearate a decrease of the pollution of the mold wotking surface is achieved which has a substantial economic effect. 

A New Blood Alcohol Breath Analyzer with Piezoelectric Detector. II. Effect of Composition on n-Octa-decanol Solvolysis of Zinc Stearate by Gas Chromatography Univ. Microfilms Int., Order No. 77-17,392, 221 pp. Diss. Abstr. Int. 38B(2) 629 (1977) CA 87 162299c... 

Pastor-Sempere [45] treated two styrene-butadiene rubbers with fumaric acid in a butan-2-ol/ethanol mixture. This resulted in improved adhesion in both cases, but the improvement with one formulation was significantly greater than the other. The lower peel strength was attributed to the presence of paraffin wax and zinc stearate. Roughening prior to treatment with fumaric acid resulted in additional improvements with both rubbers. Infrared analysis indicated that the fumaric acid was effective by introducing C=0 bonds and by reducing the concentration of zinc stearate. In addition, the fumaric acid caused a roughening of both rubbers. 

As indicated in Section 4.5 the zinc complexes catalyze two of the three modes of decomposition of dialkenyl monosulfides, one of which proceeds rapidly with B-type sulfides (Scheme 4), the other with A-type sulfides (reaction 5). In each case, the effect was very substantial (Table 6), but in each the effect could be completely nullified by the addition of zinc stearate. The mechanism of this protective effect is not known, but it is consistent with observations made in efficiently vulcanized NR at high temperatures. ... 

Dry lubricants are usually added to the powder in order to decrease the friction effects. The more common lubricants include zinc stearate [557-05-17, lithium stearate [4485-12-5] calcium stearate [1592-23-0] stearic acid [57-11-4] paraffin, graphite, and molybdenum disulfide [1317-33-5]. Lubricants are generally added to the powder in a dry state in amounts of 0.25—1.0 wt % of the metal powder. Some lubricants are added by drying and screening a slurry of powder and lubricant. In some instances, lubricants are appHed in Hquid form to the die wall. 

Accelerated sulphur systems also require the use of an activator comprising a metal oxide, usually zinc oxide, and a fatty acid, commonly stearic acid. For some purposes, for example where a high degree of transparency is required, the activator may be a fatty acid salt such as zinc stearate. Thus a basic curing system has four components sulphur vulcanising agent, accelerator (sometimes combinations of accelerators), metal oxide and fatty acid. In addition, in order to improve the resistance to scorching, a prevulcanisation inhibitor such as A -cyclohexylthiophthalimide may be incorporated without adverse effects on either cure rate or physical properties. 

The layers in the plate-like structure of talc are Joined by very weak van der Waals forces, and therefore delamination at low shear stress is produced. The plate-like structure provides high resistivity, and low gas permeability to talc-filled polymers. Furthermore, talc has several other structure-related unique properties low abrasiveness, lubricating effect, and hydrophobic character. Hydrophobicity can be increased by surface coating with zinc stearate. 

This chapter reports the results of studies on the physical, dynamic mechanical, and rheological behavior of zinc oxide neutralized m-EPDM, particularly in the presence of stearic acid and zinc stearate, with special reference to the effects of precipitated silica filler. 

Since the system is processed as thermoplastics are processed, its reprocessability was studied under repeated cycles of extrusion in the MPT. Results of reprocessability studies are shown in Table 5. It is evident that after the first cycle viscosity increased slightly, which may be due to the orientation effect. In the subsequent cycles viscosity remained almost constant. Therefore, it is concluded that the zinc stearate plasticized zinc salt of m-EPDM is melt processable just as thermoplastics. 

Solvent wiping. Rubbers tend to swell by application of solvents and the mechanical interlocking of the adhesive is favored. Although chlorinated hydrocarbon solvents are the most effective, they are toxic and cannot be used toluene and ketones are currently the most common solvents. The treatment with solvents is effective in the removal of processing oils and plasticizers in vulcanized mbbers, but zinc stearate is not completely removed and antiozonant wax gradually migrates to the mbber/polyurethane adhesive interface. Table 27.1 shows the moderate increase in adhesion produced in SBR by MEK wiping. 

ADCA is activated by zinc oxide, zinc stearate (strongly) and urea (slowly). Barium stearate, calcium stearate and triethanolamine, when added at 10 phr, moderately activate gas evolution from ADCA. They do not have very much effect on decomposition rate when the cure temperature is at 170 °C, but a marked effect above 180 °C. The rate of decomposition of ADCA is significantly influenced by the particle size of the additive. Effective dispersion and heat transfer through the particle can be a means of controlling the cell quality and the manufacturing method for the product. The correct particle size is selected to achieve the optimum balance between cure and cell development. 

Zinc soaps, which are complexes of long chain fatty acids, find similar applications in the curing and hardening of coatings to other transition metal soaps. A summary is available.123 The more important anions are 2-ethylhexanoate, naphthenate and stearate. Mixtures of zinc and calcium soaps are also effective stabilizers for poly(vinyl chloride).124 The complexes [Zn 0P(0)-(OBun)2 2] and [Zn SP(S)(OBun)2 2] both promote antiwear properties of lubricating oils.125... 

Effect of Varying Both the Zinc Stearate and Barium Chromate Content on the Burning Rate and Temperature Coefficient of a Tungsten Delay Composition... 

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