Лако-красочные материалы — производство

Recent advances have resulted in chemical modification of conventional liquid polysulfide polymers in a one-step reaction with dithiol, as follows: HS-[CH2CH2OCH2OCH2CH2—S—S|nCH2CH2OCH2OCH2CH2SH + HSRSH Liquid polysulfide polymer Dithiol catalyst Segmented lowermolecular-weight liquid polysulfide Dithiol-modified liquid polysulfide polymer These new dithiol-modified liquid polysulfide polymers have lower viscosity and improved compatibility with formulating ingredients (e. g., plasticizers, pigments, […]

Preparation of liquid polysulfide polymers has been discussed extensively [1-4]. The polymer is synthesized by reacting aqueous sodium polysulfide with bis(2-chloroethyl) formal. Cross-linking is introduced by including a small amount of 1,2,3-tri-chloropro — pane. The reactions of polymerization done at 100°C produce a mixture of chain lengths in which sulfur is present as — C-S2-C- […]

Naim Akmal[14] University of Cincinnati, Cincinnati, Ohio, U. S.A. A. M. Usmani Firestone, Carmel, Indiana, U. S.A. I. INTRODUCTION High-sulfur-containing polymers known as polysulfides were introduced by Thiokol in 1928. The solid polysulfide polymers contain 37 to 82% bound sulfur, but the more important liquid polymers containing about 37% sulfur find application in high- performance […]

Elastomeric adhesives are formulated from one or more of the many synthetic rubber polymers (or natural rubber) to provide highly flexible, resilient bonds to a variety of substrates. These compounds are based on several basic polymer types and are available in a wide selection of forms for processing by a variety of assembly methods. The […]

There are numerous market studies of the adhesive and sealant industry. Some even evaluate subsections of the marketplace, covering, for example, only pressure sensitive products and/or applications, only structural or high performance materials, major end use markets such as packaging or construction, and the raw materials used in making adhesives and sealants. For the most […]

EPDM was also introduced in the 1960s. This is a relatively saturated polymer structure with a diene, or double bond carbon monomer, added to provide functionality to the polymer chain. EPDM performs in many respects like butyl rubber in that it has excellent resistance to ozone and oxygen degradation, and has superior UV and weathering […]

A true synthetic natural rubber was introduced in the mid-1960s with the exact same chemical structure as latex tapped from a tree. The difference is that natural rubber comes with a variety of other ingredients in the latex that can both add and detract from performance, while polyisoprene is considered relatively ‘‘pure.’’ In addition, there […]

A small, but ultimately very important, part of the elastomer-based adhesive and sealant market is devoted to fluoropolymers. Most often processed as a solvent-based fluoro­carbon rubber mixture, these products are often used as sealants for applications requir­ing a high degree of chemical resistance, particularly where temperatures may rise above 210°C. These polymers exhibit excellent retention […]

Even before World War II, reclaim rubber was a popular material for many adhesive and sealant applications. At that time, virtually all rubber was natural rubber, which allowed material that had been de-vulcanized to be processed simultaneously with and to extend the new raw materials. Reclaim rubber has the advantage of already containing a selection […]

As was noted earlier, virtually any elastomeric material can be, and probably is cur­rently, made into an adhesive or sealant. All elastomers are soluble in one or more organic solvents which allows the production of a solvent-based adhesive. Many elasto­mers are polymerized in an emulsion process, which yields a latex. And a number of elastomers […]