Vulcanizing latex

Vulcanizing latex adhesives are used in the manufacture of textiles, rugs and carpets. The vulcanizing ingredients are sulphur, zinc oxide and accelerators (for example, zinc dibutyldithiocarbamate and zinc mercaptobenzothiazole to produce vulcanization at room temperature). 

Figure 15.7 Results demonstrating that much more polymeric material can be extract by suitable organic solvents bom vulcanizates derived from polystyrene-polybutadie blends than from vulcanizates from styrene-butadiene copolymers (Shundo et al. [19 ( ) peroxide-vulcanized copolymers (O) sulfur-vulcanized copolymers (O) radi don-vulcanized copolymers (A) peroxide-vulcanized latex blends (A) sulfiir-vulcaniz< latex blends (A) radiation-vulcanized latex blends ( ) peroxide-vulcanized roll blenr ( ) sulfur-vulcanized roll blends (Qf) radiation-vulcanized roll blends. The compoun for peroxide vulcanizates and sulfur vulcanizates were as given in the cation Figure 15.6. The compound for radiation vulcanization was (parts by mass) polymer 10 calcium caibonate ICIO. Roll blending was done at 110°C. Peroxide and sulfur vulca-izatkxis were carried out at 150°C. Radiation vulcanization was achieved using 10 n from a cobaIt-60 source in air at normal ambient temperature...

Eastman C-11 Ketone Eastman EB Eastman PM Acetate retarder, ttimeis Eastman PM Acetate retarder, vulcanization latex Benzoic add... 

Vulcanizing latex adhesives are used in the manufacture of textiles, rugs and carpets. 

Apart from pre-vulcanized latex where the rubber molecules have been chemically crosslinked by sulfur, the chemical nature of the rubber molecules of the other latices described above remain chemically intact during and after the process. There are several other latexes available on the market in which the rubber molecules of the latex have been chemically modified. The chemical reactivity of the rubber molecules arises from the olefinic structure of the cis-1,4-isoprene unit within the molecule, which can undergo rapid reactions with, for example, halogens, ozone and hydrogen chloride. Some of these will be described in this section. They are prepared to serve niche applications. 

After the pre-vulcanized latex compound has been prepared, the next step is to obtain the shape to be made set the shape and then vulcanize. The dilferent latex processes classified according to the method of shaping are ... 

There are four forms in which natural rubber can be used as unvulcanized latex, unvulcanized dry rubber compound, vulcanized latex, or vulcanized dry rubber compound. 

Journal of Applied Polymer Science 64, No.3, 18th April 1997, p.553-66 PERMEABILITY AND MATERIAL CHARACTERISTICS OF VULCANIZED LATEX FILM DURING AND FOLLOWING CYCLIC FATIGUE IN A SALINE ENVIRONMENT Dillon J G Schroeder L W US, Food Drug Administration... 

The major use of vulcanizing latex adhesives is in the manufacture of textiles, rugs and carpets, and closely allied products such as rubberized hair. As in many other latex applications, ultraaccelerators are used to effect vulcanization. The materials used must be stable in alkaline dispersions, although they need not be active, since if the alkali is ammonia it will normally be removed early in the drying/vulcanization process. The vulcanization ingredients, sulfur, zinc oxide, and the insoluble accelerators must be added as dispersions in water, and these are conveniently prepared at 50% solids and stabilized by an anionic surfactant. Such dispersions may be made by ball-milling or may be easily purchased premade from specialist suppliers. Soluble accelerators can be added as solutions directly to stabilized latex, but the solutions have a much more limited life than do dispersions. 

Unlike vulcanizing latex adhesives, which have a storage life measured in weeks, vulcanizing solution adhesives have a limited pot life and are stored as two-component mixtures. The two parts are mixed immediately before use and the solution will then have a workable life of perhaps 2-4 hours before gelation occurs. It is usual to formulate the two parts with the sulfur... 

Recently a ntmber of works have been published in which the peculiarities of the structure of vulcanized latex films are described in detail. By means of a number of different methods, it was determined that these films have a microheterogeneous structure which represents the combination of a highly vulcanized polymer on the surface layer of latex globules and an unvulcanized polymer inside the globules. The relation between the topology of the vulcanizing network of latex films and their properties has been described ". The present work is devoted to an investigation of the kinetics of vulcanization process of latex films. 

The results of mechanical tests, presented in Figure 5, show that the tensile strength of vulcanized latex films surpasses considerably that of analogous vulcanized rubbers (30-35 kg/cm ). This fact, already determined repeatedly for other types of rubber, can be explained in terms of the peculiarity of network of latex films distribution. 

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