Abstracts of the VKRT meetings of Plastic and Rubber sector      


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  Meeting Abstracts: Select & Consult

Abstract of Nieuwe Technologie     2000

The Future Quality Control of Modern Factory Mixing Process.
Polymer to Finished compound characterisation using dynamic mechanical analysis as unique source of data

Polymer manufacturing process is inherently variable, principally due to the variability of the major raw material components, synthetic and natural rubber and polymers, and to a lesser extent, other key raw materials (filler, accelerators etc.).
The equipment used in factory mixing also contributes its share of variables, caused by the type of equipment used (age, efficiency, size) and in control (temperature, power, time). A given formulation with a mixing and processing schedule set to achieve optimum throughput and performance, may not process successfully in different production sites or even in different lines at the same site.

Dynamic mechanical analysis is an excellent tool to monitor incoming polymers, masterbatches and uncured fully mixed compound quality. It provides reliable results correlating closely to compound processing characteristics, such as extrudate swell and extruder output enabling detailed characterisation and selection of polymer sources, grades and batches.
In the thermoplastic area, compounding and mixing have shown an increasing importance to offer material with optimum properties for used processing tools. Dynamic testing has largely supplemented traditional testing techniques to assure product consistency and processing quality assurance.
Optimum mixing and processing conditions can thus be established and mixed compound characteristics verified, thus reducing variability, process down time and eventual scrap.
Conventional testing by Mooney and rheometer is neither capable nor sensitive enough for fully detailed characterisation, particularly for polymer microstructure, and with masterbatches, to ensure optimum throughput of high quality compounds.
Dynamic mechanical analysis can now be fully automated. This technique has the potential for real, online quality control. This capability has been demonstrated at a tyre manufacturer during extended testing of production masterbatches, final mixes and raw polymers. Large compound property variations were found. These variations may be due to variations in the polymers but also to variations in the mixing process. Variations in mixing behaviour were successfully correlated to key polymer properties.
Dynamic mechanical testing provides in a single test, the key parameters that relate to compound properties on the factory floor thus ensuring the control necessary to achieve high quality and efficient production.

New Radial Tyre Technology and its effect on Quality and the Environment

Since the mid-1980s, compounds based on silica reinforcement have partially displaced those based on carbon black to give improvements in tire performance parameters such as rolling resistance and traction. A reduction in rolling resistance can also reduce fuel consumption and therefore the emission of "greenhouse gases" such as CO2. These compounds also use Silica and silane and increasing quantities of solution SBR and BR.

New methods of tyre manufacture also reduce the energy consumption and improve tyre quality.
This paper discusses these developments.

Ontwikkelingen in high-performance bandengarens

In radiaal autobanden is het karkas verstevigd met een of meer koordlagen uit synthetisch garen. Het standaardmateriaal is polyester dat sterk en goedkoop is. Rayon (cellulose) blijft echter populair hoewel de sterkte lager is. De reden is dat cellulose bandengaren lagere krimp en hogere modulus heeft, en niet smelt. Er waren twee doelstellingen die bij de ontwikkeling van nieuwe high-performance garens een rol speelden. (1) Een materiaal dat veel sterker is dan polyester, waarmee twee lagen koord vervangen kunnen worden door

Reactief mengen van Silica met Rubber

Gedurende de laatste jaren bestaat er een sterk toegenomen belangstelling voor het gebruik van silica als versterkende vulstof voor bandentoepassingen. Het voordeel van het gebruik van silica in plaats van roet is een verlaging van de hysteretische verliezen gedurende het dynamisch vervormen van de rubber. De silica-versterkte "Green Tyre" heeft derhalve een ca. 30% lagere rol-weerstand, hetgeen zich laat vertalen naar ca. 5% brandstofbesparing.

De verdraagzaamheid van silica met de rubber matrix is laag. Silica is een polaire substantie, terwijl rubber polymeren zich vooral a-polair gedragen. Daardoor is het verkrijgen van een goede silica-dispersie in een rubber mengsel een moeilijke opgave. Om de verdraagzaamheid tussen silica en rubber matrix te bevorderen voegt men bi-functionele coupling agents toe aan het mengsel. De meest gebruikte coupling agent is bis(3-triethoxysilylpropyl)-tetrasulfide, gewoonlijk aangeduid met TESPT, Si-69 (Degussa) of Silquest A1289 (OSI Specialties Group, Crompton Corp.). Het vergemakklijkt de vulstof-verdeling gedurende het meng-proces. Daarnaast neemt men aan, dat er chemische reacties plaatsvinden tussen de silica en de coupling agent enerzijds en de coupling agent en rubber matrix anderzijds.

Het mengen en vulcaniseren van rubber, gecombineerd met de verschillende mogelijkheden om de coupling agent aan het mengsel te doseren, geeft aanleiding tot verschillen in de uiteindelijk verkregen vulcanisaten. De presentatie gaat in op de invloed van meng-variabelen voor een S-SBR/BR Green Tyre compound - vulgraad, rotor snelheid, volgorde van toediening van de ingredienten en mogelijkheden om de ontwikkeling van de batch-temperatuur te be

The petro-chemical cycle & the chemical (Elastomers) industry into the new millennium

The paper was made in a co-operation between EniChem and the Belgian PRI.
The Elastomers market is becoming more sensitive to offer & demand, to global trade and feedstock scenarios. The Petro-chemical business is a cyclic business and divestment in commodity products goes faster than investments.
This paper gives an overview of the last 3 years and tries to give a possible scenario for the next years in to the new millennium.

The presentation will cover the commodity Elastomers like SBR & BR, specialities like CR, NBR, EPR SBC, and feedstock's like Nafta, Butadiene, Styrene, Ethylene and others.
This paper has no commercial objectives but makes an effort in making people more alert to changes that take place in this sector and the influences on product pricing.