Latex Products

Latex Products


rubberlike products made from aqueous dispersions of natural rubbers, or latices.

The industrial process for the manufacture of latex products includes the following steps: (1) preparation of the latex mixture, which contains (in addition to the usual ingredients of a rubber stock) surface-active materials (used to facilitate the dispersion of the ingredients in the latex and to impart storage stability to the mixture), thickeners, antiseptics, and antifoaming agents; (2) production of the semifinished latex product, or gel; and (3) contraction (syneresis) of the gel, drying, and vulcanization of the latex product.

Most methods for the production of gels are based on the interaction of latex globules with astabilizing additives, such as electrolytes, which lower the stability of the colloidal system and thereby accelerate the coagulation of the latex. In the production of dipped latex products, the gel may be produced by immersing the mold, or former, which has the shape of the product, first in an electrolyte solution (for example, CaCl2) and then in the latex mixture (ionic deposition). Another method involves immersing the former, preheated to 60°-100°C, in a latex mixture containing an additive that astabilizes the system at elevated temperatures (for example, polyvinyl methyl ether); this process is called thermal sensitization. A third method involves the multiple immersion of the former in the latex mixture, drying each layer of gel between immersions (multiple dip).

The ionic deposition and thermal sensitization methods show high productivity. For example, a semifinished product with a wall thickness of about 1 mm may be produced in several minutes by the first method and in less than 1 min by the second. Dipped latex products include radiosonde and weather balloon cover envelopes, surgical and household gloves, sanitary products, toys, and football bladders. The wall thickness of these products as a rule does not exceed 2–3 mm.

Products with irregular shapes and thick walls, such as the working elements, or fingers, of tea harvesters and light sponge-rubber, or foam rubber, articles (for example, automobile seats), are produced by a method based on gelation of the latex mixture. A mixture containing a gelating agent, such as sodium silicofluoride, charged into a mold; this quickly astabilizes the entire system (for foam rubber, the mixture is foamed before gelation). Certain products, such as latex threads, are produced by extruding the latex mixture through spinnerets into baths filled with an astabilizing agent, such as acetic acid solution.

Syneresis, which is required not only to contract the gel (that is, for “squeezing out” the aqueous phase, or serum) but also to accelerate the subsequent drying of the latex product, is performed in water at room temperature. The latex products are dried in air chambers for as long as 15 hours at 40°-80°C. The drying time may be significantly reduced by combined heating with industrial-frequency currents and infrared radiation. The products are usually vulcanized in hot-air ovens at 100°-140°C.

The possibility for the great variety of latex products has to do with the relatively simple production technology, the high productivity of the process, and the possibility of mechanizing and automating all stages of the process. In addition to articles that can be produced only from latices, such as foam rubber and thin-walled seamless meteorological casings, there are articles that can be produced either from solutions of solid natural rubbers (rubber adhesives) or from latices (gloves and threads). Latex technology precludes the use of toxic and flammable solvents.


References in periodicals archive ?
Among his topics are raw materials, the degradation of elastomers, the reinforcement of latex systems by the use of fillers, finishing operations for dipped latex products, some analytical methods used in latex dripping operations, and potential future trends in the latex dipping industry.
*Currently, latex products have a higher market share as these can be used with lubricants and sex toys, which makes them the preferred choice of customers
Revising entries for Disulfiram, Thiuram, Thiuram disulfides, and Thiuram monosulfides to combine under a single entry for Thiurams (CAS 97-77-8; 137-26-8) with a maximum use of 14% in latex products
Further, application segment of the the market is sub-divided to industrial, gloves, consumer goods, automotive, general rubber goods, foot wear, auto-tire sector, latex products, medical and other applications.
Then the awareness of AIDS resulted in increased usage of various latex products, including surgical and medical gloves and condoms, leading to a sharp increase in NR consumption.
By Kim Jae-heun Hana Tour and Mode Tour, the country's top two travel companies, have been found to have conspired with subcontractors in Thailand to draw tourists from Korea to buy latex products containing radioactive materials, according to industry insiders.
OMNOVA Solutions (NYSE: OMN), a company involved in performance-enhancing chemistries and surfaces used in products for a variety of commercial, industrial and residential applications, has increased the global price of nitrile elastomers and styrene-acrylic polymers, styrene-butadiene latex products and acrylic polymers.
M2 EQUITYBITES-January 11, 2017-OMNOVA Solutions introduces higher prices for nitrile elastomers, styrene-acrylic polymers, styrene-butadiene latex products and acrylic polymers
The business is reported to have a global customer base and production facilities in both the UK and at its Sri Lanken subsidiary, Quality Latex Products Ltd.
Eka manufactures and sells styrene-butadiene latex products for the paper and board industry mainly in Nordic countries.
Apart from dry rubber products, latex products manufacturing industry also has expanded over the years to meet the world demand for examination gloves, condoms, latex thread, etc.
Reichhold introduced new waterborne resins such as BECKOSOLAQ[R] 400 alkyd latex products designed for the formulation of non-highway striping coatings.