Rubbers, additives Processing oils

At Goodyear laser-desorption MS has been used for direct analysis of rubber additives (e.g. antioxidants, antiozonants, vulcanising agents, processing oils, silica fillers, etc.), in situ at the surface of an elastomeric vulcanisate [74,75]. 

FD-MS is also an effective analytical method for direct analysis of many rubber and plastic additives. Lattimer and Welch [113,114] showed that FD-MS gives excellent molecular ion spectra for a variety of polymer additives, including rubber accelerators (dithiocar-bamates, guanidines, benzothiazyl, and thiuram derivatives), antioxidants (hindered phenols, aromatic amines), p-phcnylenediamine-based antiozonants, processing oils and phthalate plasticisers. Alkylphenol ethoxylate surfactants have been characterised by FD-MS [115]. Jack-son et al. [116] analysed some plastic additives (hindered phenol AOs and benzotriazole UVA) by FD-MS. Reaction products of a p-phenylenediaminc antiozonant and d.v-9-lricoscnc (a model olefin) were assessed by FD-MS [117],... 

Facilitate pre-vulcanisation processing, increase softness, extensibility and flexibility of the vulcanised end-product. The rubber processing industry consumes large quantities of materials which have a plasticising function complex mixtures (paraffinic, naphthenic, aromatic) of mineral hydrocarbon additives, used with the large tonnage natural and synthetic hydrocarbon rubbers, are termed process oils. Because of the complexity of these products, precise chemical definition is usually not attempted. If the inclusion of an oil results in cost reduction it is functioning as an extender. The term plasticiser is commonly reserved for synthetic liquids used with the polar synthetic rubber. 

In rubber compounding, the addition of a high proportion (40-50 phr) of a rubber processing oil to an elastomer with the object of improving the processibility of a tough polymer and/or cheapening the compound. 

Petroleum oils are offered to the rubber industry to meet two basic processing and compound requirements to act as a processing additive, or to act as a rubber extender and softener. The classification depends upon the oil volume added to the rubber compound. As processing additives, the oil addition level is usually no more than 5-10 phr for additions in excess of this the oils are regarded as extenders. 

Oils of the three types are offered in a range of viscosities and this will influence their processing character to some extent, although there is little evidence that it will have much influence on the ultimate compound physical properties, at least in natural rubber compounds. The small additions of oil to a compound help with filler dispersion by lubricating the polymer molecular chains and thus increasing their mobility. There will also be some wetting out of the filler particles which enables them to achieve earlier compatibility with the rubber and improve their distribution and dispersion speed. 

The majority of plasticiser consumption is in CR and NBR. Plasticisers are also technically important in chlorosulphonated polyethylene, hydrogenated nitrile, ethyl acrylate copolymer, epichlorohydrin copolymer and ethylene-acrylic terpolymer. At around 10 kt/annum (Europe), total consumption of plasticisers is on a much smaller scale than the process oils used in hydrocarbon rubbers. Typical addition levels are below 20 phr. 

Processing oil is a well-known additive for rubbers and is commonly employed in PP/EPDM TPVs [10-12]. It lowers the hardness and improves the processability. The oil, in most cases paraffinic oil, can be considered as a low molecular weight olefin. The difference in polarity between the three components is small, and the oil is present in both the PP and in the elastomer phases [67]. In order to understand the mechanical and the rheological properties of olefinic thermoplastic elastomers (OTPEs), the concentration of oil in each phase must be known. 

For the investigation of a butadiene-styrene rubber, a set of three SEC columns in series was used 500 x 8 mm, d0 = 150 nm 500 x mm, d0 = 25 nm 800 x 8 mm, d0 = 4 nm, all three with dP = 10 pm. The flow rate was 1 ml/min. The injection amounted to 200 pi of a 2 % solution from which the carbon black had been removed. Although the additives of interest were separated from the polymer, they were still covered by an intense band from process oil. Hence, coupled-column chromatography with reversed-phase separation of SEC eluates became neccessary. 10 pi of the latter were injected into a C 8 column (250 x 2.2 mm dP = 10 pm) and analyzed at 0.5 ml/min flow rate through a water/acetonitrile gradient (rising from 20% B by 6%/ml). Here, UV detection was performed at 254 nm. The peaks of the additives could be clearly separated from the process oil band. The technique also proved useful for checking... 

Crude oil is used both directly as a fuel and as a feedstuff for the petrochemical factories to produce commercial fuels, synthetic rubbers, plastics, and additional chemicals. Oil refineries were originally placed near the oil fields partly because natural gas, which could not then be economically transported long distances, was available to fuel the highly energy-intensive refining process. But since 1950, crude oil has bwn transported by tankers and oleoducts to local refineries for strategic reasons. 

The synthetic rubber industry uses a number of hydrocarbon additives, specifically called process oils (to act as a plasticiser, used below 20 phr) or extenders (used to keep the costs down). There are a wide range of mineral oils used as process oils, produced by blending of crude oil distillates and these may be either paraffinic, naphthenic or aromatic. Process oils containing polycyclic aromatic hydrocarbons, are classified as potential carcinogens (and their use is decreasing considerably). 

Uses Chemical intermediate for oxidation, ethoxylation, sulfation, amination, esterification coemulsifier and direct additive in coatings plastics additive (processing aid, lubricant, dispersant, antioxidant) antiblocking agent in rubbers thickener, moisturizer, pigment dispersant, oil binder, stabilizer in cosmetic creams, lotions, lipsticks, antiperspirants, and soaps in adhesives for food pkg. 

Chem. Descrip. French process zinc oxide from recycled zinc metal CAS 1314-13-2 EINECS/ELINCS 215-222-5 Uses Pigment, filler for rubber, zinc chems., oil additive, tape/adhesives, paint, glass, wire insulation, agric., electrogalvanizing, and brake lining industries... 

Hayes and Altenau [34] were the first to report the use of MS to directly characterise antioxidants and processing oil additives in synthetic rubbers. Since then, various MS techniques have been applied to the analysis of rubber and polymer additives either as extracts or on the sample surface by laser techniques as reviewed by Lattimer and Harris [35]. Lattimer reviewed the present situation regarding MS in polymer analysis [36]. Analysis of polymer extracts by MS has proved challenging. Electron impact mass spectra (EI-MS) are often difficult to interpret due to the high concentration of processing oils and the additives in the extract, and excessive fragmentation of the molecular ions. Desorption/ionisation techniques such as field desorption (ED) and fast atom bombardment (FAB) have been found to be the most effective means for analysing polymer and rubber extracts [37, 38]. 

LD-MS has proven a uniquely useful technique for the direct characterisation of ruhher-compound surface species. Mass spectra were obtained for intact molecular ions (M+) of organic chemical rubber additives such as the aromatic processing oil, and the aromatic antiozonant and antioxidants incorporated to protect the rubber. MW information from... 

The autohesion of rubber compounds is found to marginally decrease with increasing amounts of plasticiser/processing oils such as aromatic, naphthenic or paraffinic [5]. Since plasticiser/processing oil improves the chain mobility of the rubbers this behaviour shows that interdiffusion alone cannot explain all the factors associated with tack or autohesion. But if the modulus is maintained at a constant by the addition of carbon black, oil essentially has no effect on adhesion [9]. 

It is possible to increase significantly the concentration of plasticizers, anti flammable agents, and oleophilic additives by adding oleogels to rubber or plastic. Figure 5 shows the increased amount of processed oil... 

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