Academic literature on the topic 'Resorcinol Formaldehyde Latex'

Abstract In this study, the chemical reactions of the epoxy silane subcoat with resorcinol formaldehyde latex (RFL) topcoat were studied using model compounds. The experimental evidence indicated that various reactions took place between the γ-GPS and RFL. The epoxy group may react with the resorcinolic alcohol, methylol, and the residual silanol. Some reactions are catalyzed by NaOH or pyridine derivatives. Among the reactants, resorcinolic alcohol is the most active component in the presence of alkaline materials. It also has the highest concentration in an ordinary application. Thus, the resorcinolic alcohol opening the epoxy ring can be considered as the major reaction between the epoxy coupling agent and RFL. The 2-alkylpyridine component of the latex acts as a catalyst for the reaction. The residual silanol may consume the epoxy group upon heating during the processing. Since the reaction rate constant is low as compared to the silanol self-condensation and the interfacial reaction, and, furthermore, the concentration of the residual silanol is low, it will not influence the bonding at the silane/matrix interface.

Abstract The last comprehensive review of tire-cord adhesion to rubber was reported by T. Takeyama and J. Matsui in Rubber Reviews for 1969. They covered this subject in depth from its scientific beginnings and dealt mostly with rayon, nylon, and polyester tire-cord adhesion. The objective of this present review will be to up-date the 1969 review. The resorcinol-formaldehyde-latex (RFL) adhesive system developed as a fiber adhesive in the early 1940's is still in use throughout the rubber industry at the present time. No other resin has replaced the resorcinol-formaldehyde resin and no other latex has replaced 2-vinylpyridine-butadiene-styrene latex as components in adhesive dip recipes. This will probably be true into the foreseeable future. There was really no need to improve the adhesion of rayon and nylon to rubber, so very little development work was done with the adhesion of these two fibers. However, a considerable amount of work was done with polyester adhesion and this coincided with the expanded use of poly(ethylene terephthalate) fibers in passenger tires. Much of this effort was concerned with single-step adhesive dips where the adhesion activating ingredients were added to a standard RFL mixture.

A Plasma-Enhanced Chemical Vapor Deposition was chosen in order to deposit an organic thin film on polyethylene terephthalate monofilament to increase its adhesion with the rubber compound in a tire. The aim of the work is to find an alternative “green” method to the classical chemical dipping with Resorcinol Formaldehyde Latex: plasma treatments are environmentally friendly and easy to use. 2-isoprepenyl-2-oxazoline (2-iox) was employed as precursor and the treatments were performed in a vacuum system, both in a continuous regime and a pulsed regime. Initially, the coatings were deposited on polyethylene terephthalate sheets to study the wettability (by the measurement of contact angle) and the thickness (by profilometer) of the plasma polymer. The chemical characterization was investigated by Infrared and X-ray Photoelectron spectroscopies. Finally, the adhesion of the polyethylene terephthalate sheets was measured by Peel Test, using the coating as adhesive and as a pre-dip. The measurement of the peel force made it possible to optimize the plasma parameters that were applied on the monofilament. The adhesion was estimated by the measure of the extraction force and the evaluation of the coverage compared with those of the classical chemical treatment Resorcinol Formaldehyde Latex.

Waste resorcinol – formaldehyde – latex (RFL) dip solid was collected from the suction chamber of a typical tyre industry dip unit. The cure acceleration effect of the waste material was studied in a natural rubber (NR) based filled compound. The effect of the waste material was examined in a natural rubber (NR) based ply skim compound of a bias tyre with cure package modification. Rheological, tack index, stress-strain properties, swell index, dynamic mechanical properties, H-adhesion before and after anaerobic aging was also studied.

Adhesion of cords to elastomers is crucial for many elastomeric products, such as tires and V-belts. The best adhesion system so far is based on a combination of resorcinol, formaldehyde, and a latex (RFL). However, this cord treatment has serious disadvantages in terms of processing and toxicity. A promising alternative is a plasma treatment of the cords prior to be embedded in the elastomer. For rayon cords, a plasma polymerization of sulfur-containing precursors results in adhesion levels close to RFL treatment. However, for polyethylene terephthalate (PET) cords, this treatment is not satisfactory. For this type of cords, a water-plasma activation followed by a silane dip is more promising, as 72% of the adhesion level of RFL treatment could be achieved. For rayon, an even higher adhesion level was realized.

Abstract Resorcinol Formaldehyde Latex (RFL) adhesive systems have been used for over forty years to bond synthetic fibers to rubber compounds. The original RFL formulation was developed by Charch and Maney. The adhesive was applied primarily to rayon fibers and later extended to nylon and glass fibers. At the same time, the formulation evolved with the introduction of synthetic latexes and preformed resorcinol formaldehyde resin solutions. The RFL treated fibers are used to reinforce rubber products (e.g., tires, conveyor belts, hoses, V-belts). With the commercialization of polyester fibers, it was found that the RFL system did not satisfactorily adhere polyester to rubber compounds. The difficulty in bonding to polyester fibers has been attributed to the lack of reactive sites in the polymer structure, as well as its hydrophobic nature. New adhesive systems were developed which consisted of free isocyanates in solvent solutions. These systems were undesirable due to the associated health and fire risks. As a result, the use of aqueous dispersions of blocked isocyanates was investigated. Blocked isocyanates consist of isocyanate molecules which are chemically reacted with a blocking agent to prevent reactions with other materials at room temperature conditions. At higher temperatures, the blocking materials dissociate to free the reactive isocyanate groups. The blocked isocyanates are generally available in solid form and are chemically stable in water. Common blocking materials include phenols, oximes, and lactams. Shoaf developed a two-step, water based, adhesive system that effectively bonded polyester to rubber. This system consists of a first-step dip application which contains a polyepoxide and blocked aromatic polyisocyanate. In the second step, the treated fiber is overcoated with an RFL mixture. The reaction product of the polyepoxide and polyisocyanate has been identified as a polyurethane structure which physically adheres to polyester. Iyengar attributed this physical interaction to the similarity between the cohesive energy density values for the polyester and polyurethane structures.

The Waste (England and Wales) Regulations encourage business to recycle their waste, as an alternative to landfill. This study has evaluated a number of processing techniques with respect to a difficult to recycle, technical textile, in order to develop recycling opportunities. Resorcinol formaldehyde latex (RFL) coated nylon 66 is a high performance fabric used as an interface to reinforce rubber products such as timing belts. The characteristics of the RFL coated woven fabric, assessed in comparison to equivalent uncoated fabrics, showed increased stiffness and decreased tear resistance. This was followed by the evaluation of three reduction processes:1) The Laroche Cadette shredder;2) The Hollander beater;3) The Intimus disintegrator. The fibre length, coating integrity and degradation properties were assessed for each of the reduction techniques. The longest fibres were produced by the Laroche Cadette shredder, this method proved most suitable for textile processing. The coating was unaffected and little degradation occurred. The Hollander beater produced mid-length fibres; however, fibres as short as 2mm could also be achieved. The material did not degrade, as water used within the process reduced heat build up, the coating remained adhered to the fibre. The Intimus Disintegrator produced the smallest fibre length and produced the greatest processing problem due to heat build up and degradation. Particles in addition to fibres were formed but were not crystalline in nature, and were difficult to process further. Processing using paper, textile, plastic and rubber technology were trialled with varying success. The recommended recycling route was found to be through reduction using the Hollander beater followed by incorporation of the waste as filler in rubber composites. RFL coated fibres gave additional strength to the rubber at high filler contents of 37.5% in comparison to uncoated waste filler also trialled. This was due to the surface chemistry of the RFL coated nylon fibre. The RFL coated nylon 66 filler also enabled the composites to exceed tear specifications required for hardwearing footwear. Fibres were effectively separated by length using forward flow and reverse flow hydrocyclones, separating 10mm and 3mm length fibres, which would prove useful for obtaining optimum particle size for reinforcement during the reduction process. Alternate processed trialled enabled the RFL fibres to be formed into a paper sheet using 50% cellulose pulp but textile processes proved unsuccessful. Moulded pieces formed though compression moulding were able to be produced from coated and uncoated fabric pieces, however many voids were present, limiting the usability.

Dissertação de mestrado integrado em Engenharia de Materiais
Reinforcements are an important part of the tire construction, helping to give good stability, ensuring wellfunctioning and safety to the drivers. In order to achieve such conditions, high-performance textile reinforcement materials are being investigated for industry purpose, especially where higher velocities are needed. Currently, hybrid Aramid/Nylon cords have been the most studied and used material for the referred application, but not yet satisfactory in some areas, as for example racing vehicles and aerospace industry. Poly(p-phenylene-2,6-benzobisoxazole) is a high-strength material with better mechanical properties and reaching higher degradation temperatures (650ºC) than Aramid, being considered as a promising candidate. However, little information is available regarding the application of Poly(p-phenylene- 2,6-benzobisoxazole) as tire reinforcement, due to the difficulty of surface treatment on these inert fibers. The aim of the following thesis is to obtain a hybrid reinforcement with improved mechanical properties compared to the one existing in the market, while the adhesion between the textile and rubber parts must be acceptable for industrialization. For this purpose, different surface treatments were used based on conventional treatment or a more environmental friendly one. The referred treatments were either composed by epoxy or atmospheric plasma activation, while the main coating is due to a resorcinolformaldehyde-latex (RFL) solution. In order to perform such optimization, a numerous of equipment’s were used, starting from Laboratory Twist and Dip Unit up to characterization methods based on tensile, shrinkage and peel tests. The analysis done during the optimization process show a high difficulty to obtain a commitment between both, good tensile curve behavior and good adhesion to rubber. Thus, from the best results obtained an improvement of mechanical properties was reached compared to the reference cord existent in the company, while the adhesion properties came close to the minimum acceptable for industrialization. In conclusion, it can be said that the adhesion properties have the need of improvement in order to achieve a reinforcing material able to be used in the tire industry.
Reforços são uma parte importante da construção de um pneu, que ajudam a promover boa estabilidade, garantindo o bom funcionamento e segurança aos condutores. De modo a alcançar tais condições, têxteis de alta performance estão a ser investigados na industria, especialmente para casos em que altas velocidades são necessárias. Na atualidade cordas hibridas de Aramida/Nylon tem sido as mais estudadas e utilizadas para a aplicação referida, mas ainda não são satisfatórias em algumas áreas, tais como carros de corrida e industria aerospacial. Poli(p-phenileno-2,6-benzobisoxasol) é um material de elevada resistência com melhores propriedades mecânicas e atingindo maior temperaturas de degradação (650ºC) comparado a Aramida, sendo assim considerado uma aposta promissora. Contudo pouca informação se encontra disponível em relação a aplicação deste material em reforços para pneus, devido a dificuldade de tratamento superficial nestas fibras inertes. O objetivo desta tese é de obter um reforço hibrido com propriedades mecânicas melhoradas comparativamente aos existentes no mercado, enquanto que a adesão entre a parte têxtil e borracha tem de ser adequada para industrialização. Para estre propósito, diferentes tratamentos superficiais foram usados baseando-se em tratamentos convencionais e outros mais amigos do ambiente. Os tratamentos referidos são compostos por uma ativação de com solução de epóxido ou através de um plasma atmosférico, enquanto que a revestimento principal é baseado numa solução de resorcinol-formaldaído-latex (RFL). Para realizar tal otimização, diversos equipamentos foram usados, iniciando com a unidade de laboratório de torção e imersão seguido de técnicas de caracterização baseados em ensaios de tração, encolhimento e testes de adesão. As analises efetuadas demonstram uma elevada dificuldade de obter boas propriedades mecânicas e de adesão a borracha em simultâneo. Dos resultados foi possível obter um melhoramento das propriedades mecânicas relativamente ao material de referência existente na empresa, enquanto que a adesão se encontra próximo de limite inferior aceitável para industrialização. Em conclusão é possível afirmar que as propriedades de adesão têm a necessidade de serem melhoradas de modo a obter um reforço capaz de ser usado na industria.