莱茵化学TK67_Rhenogran Na2Co3-70 CO F

for RCR, is well dispersed and protected in the selected epichlorohydrin polymer (CO)binder system. With this homogeneous,

fine filtered Rhenogran ?(150 micron), rub-ber parts with a high and constant quality level, can be produced at a low scrap rate.

Lead free curing of

ECO and CO compounds using Rhenogran ?Na 2CO 3-70/CO F

Harald Kleinknecht, Applications development [mailto: harald.kleinknecht@https://www.wendangku.net/doc/325613495.html, ]

Key words:automotive, hoses, hose manufacturers, ECO/CO, Rhenogran, Rhenogran Na 2CO 3-70/CO F , sodium carbonate powder, bisphenol curing system, lead-free 12-20

Abstract

Rhenogran ?Na 2CO 3-70/CO F is a substi-tute for lead derivatives. Main applications are ECO/CO compounds for the produc-tion of (multiply) gasoline hoses:

■Based on ECO/CO compounds in com-bination with FPM and ACM compound (multilayered hoses)

■Used in bisphenol curing systems as acid acceptor and activator ■Replacement for lead derivatives in such systems

■Replacement for ETU/lead derivative curing systems

Technical report No. 67

Automotive fuel hoses

T e c h n i c a l r e p o r t N o . 67 p a g e 2

There are various curing systems for curing polyepichlorohydrin compounds. In the curing systems usually used up to now for ECO/CO compounds, it is mainly lead compounds (Pb oxide, Pb-phosphite, Pb-phthalate etc.) that are used as activators/acid acceptors.Apart from the curing systems most fre-quently applied to date for vulcanising ECO/CO compounds using ETU (ethylene thiourea) and lead compounds, there are sys-tems that use other curing agents, e.g. com-pounds based on triazine or bisphenol. These systems were also often used in conjunction with lead compounds. Many different tests have shown that in the traditional systems, the lead compounds can be replaced by lead-free activators/acid acceptors. Added to this, is the fact that it is possible to replace the ETU/lead derivative systems in automotive applications completely.

The European directive on disposing of old vehicles has forbidden the use of heavy met-als for all new passenger cars and commercial vehicles since July 1, 2003. Departures from the maximum limit values are only permitted up to the June 30, 2005, where the use of lead

compounds appears to be unavoidable, for technical reasons. With effect from July 1,2005 the use of lead compounds in cars is, in general, no longer permitted in the EU. In the meantime, all the large car manufacturers worldwide have adjusted accordingly to these regulations and demand of their suppliers that they introduce lead-free car components.Rhenogran ?Na 2CO 3-70/CO F is an opti-mally predispersed polymer-bound product.The binder is an epichlorohydrin homopolymer (CO). The product is used as an acid acceptor in bisphenol curing systems for the manufac-ture of ECO/CO hoses, and in particular, for the manufacture of fuel hoses. In the case of these multi-ply special hoses, combinations of fluorocarbon polymer or fluorothermoplastics,ECO/CO compounds and in some cases even AEM and ACM compounds are used. This cur-ing system also improves the binding of the fluoropolymers to the ECO/CO compound.Typically, such a system consists of a curing agent (in this case bisphenol derivative), a phosphonium derivative as activator and an acid acceptor. Na 2CO 3has proved to be a particularly good acid acceptor.

New demands of ECO/CO compounds for automotive parts

1.

Examples of laboratory mixtures produced using Rhenogran ?Na 2CO 3-70/CO F are pre-sented below. The test values determined on pages 3-4, Table 1-3 and Fig. 1 and 2 show examples of a few mixing recipes. Characteris-tic values for describing the storage, pre-vul-canization and vulcanization behaviour were determined, as were the physical properties of vulcanized and tempered samples. The physi-cal properties were examined immediately after vulcanization and tempering as well as under various conditions of ageing.

Table 1 shows a recipe based on ECO and CO standard polymers, two typical types of carbon black (N 550, N 330), a special plasti-sizer (Rhenosin ?759), processing agents

(Aflux ?54 and stearic acid), anti-ageing agents (Vulkanox ?MB-2, Rhenofit ?CDA, Rhenogran ?NDBC-70 and Rhenogran ?Na 2CO 3-70/CO F as acid acceptor).

Examples of lead-free curing of ECO/CO using Rhenogran ?Na 2CO 3-70/CO F

2.

T e c h n i c a l r e p o r t N o . 67 p a g e 3

Table 2 and Figures 1 and 2 document the measured values of the rheological tests.

All mixtures show the anticipated good pre-vulcanization safety. Mixtures 1, 2 and 7 con-tain NDBC as anti-aging agent. They show the safest pre-vulcanization, but also slower curing

and a lower degree of curing compared with the compounds containing Rhenofit ?CDA and Vulkanox ?MB-2 as anti-aging agents.

T e c h n i c a l r e p o r t N o . 67 p a g e 4

The measured values and figures of the rheometer curves show the linear curing be-haviour typical of this curing system, a curing curve showing a constant gradient. In other words, curing always continues constantly under corresponding temperature conditions.A typical maximum or plateau, as with other

curing systems, does not occur. A comparison of the rheometer curves of the fresh com-pounds (Fig. 2) and after storage at room tem-perature for 56 days (Fig. 3) shows only slight changes and confirms the good storage stabil-ity of compounds with this curing system.

T e c h n i c a l r e p o r t N o . 67 p a g e 5

Table 3 summarizes the physical measured values determined in 2 mm and 6 mm test bodies. The 2 mm and 6 mm specimen were vulcanized, tempered and aged under the same conditions. The differences in the curing behaviour (which were already obvious during

the rheometer test) of the compounds with Rhenogran ?NBDC-70 (compounds 1, 2, 7)and the compounds with Rhenofit ?CDA and Vulkanox ?MB-2 are also apparent in the phys-ical test values established.

The delayed action of NDBC and the con-tinuous curing at higher temperatures de-scribed above lead to clear differences in the level of curing under the same curing and aging conditions. The compounds with NDBC are clearly less cured and also age at a lower rate or continue to vulcanize more slowly.These differences can be partially balanced out by adjusting the vulcanization conditions to the respective recipe.

T e c h n i c a l r e p o r t N o . 67 p a g e 6

Table 4 summarizes the test results in motor oil 5W-40 C20 after aging 72 h/100 °C, 72 h/150 °C and in water 72 h/70 °C. With these tests too, the differences in the level of curing described above are apparent in the physical test values. The test results at 100 °C in oil confirm the good stability of the ECO/CO com-pounds in mineral oils and other media com-pared to other rubbers. However, the test val-ues also show the limits of this type of rubber after 72 h/150 °C storage. The relatively strong swelling in water and continuous curing com-pared with other ECO/CO curing systems,should be noted.

T e c h n i c a l r e p o r t N o . 67 p a g e 7

High-value compounds of homogeneous quality can be produced by using Rhenogran ?Na 2CO 3-70/CO F in lead-free ECO/CO com-pounds. The very fine and at the same time hygroscopic active substance is protected by the polymer binder and is available in a form that is well dispersed and well tolerated by ECO/CO compounds. The laboratory test re-sults shown here illustrate typical data for the

types of compound described and the acti-vator/stabilizer systems used. Adapting the recipe, the processing and vulcanization con-ditions to the respective manufacturing

processes and applications, make optimization necessary in individual cases. According to applications, other curing systems (e.g. the triazine system) and additives should also be considered.

Summary

3.

Our technical advice - whether verbal, in writing or by way of trials - is given in good faith but with-out warranty, and this also applies where proprietary rights of third parties are involved. It does not release you from the obligation to test the products supplied by us as to their suitability for the in-tended processes and uses. The application, use and processing of the products are beyond our control and, therefore, entirely your own responsibility. Should, in spite of this, liability be estab-lished for any damage, it will be limited to the value of the goods delivered by us and used by you. We will, of course, provide products of consistent quality within the scope of our General Condi-tions of Sale and Delivery.

Aflux?, Rhenofit?, Rhenogran?, Rhenosin?und Vulkanox?are registered trademarks of Rhein Chemie Rheinau GmbH, Germany.

Vulkanox?is a registered trademark of Bayer AG, Germany.

Rhein Chemie Rheinau GmbH Duesseldorfer Strasse 23-27 68219 Mannheim, Germany Phone: +49(0)621-8907-0

Fax: +49(0)621-8907-594 rubber.rcr@https://www.wendangku.net/doc/325613495.html, Rhein Chemie Japan Ltd. Marunouchi Kitaguchi, Bldg. 23 F 1-6-5 Marunouchi, Chiyoda-ku Tokyo 100-0005, Japan

Phone: +81 (0)5293-8041

Fax: +81 (0)5293-8041

rubber.rcj@https://www.wendangku.net/doc/325613495.html, https://www.wendangku.net/doc/325613495.html, Rhein Chemie Corporation

145 Parker Court

Chardon, OH 44024, USA

Phone:+1-440-279

Fax:+1-440-285

rubber.rcc@https://www.wendangku.net/doc/325613495.html,

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Qingdao 266043, PR China

Phone: +86-532-482-1670

Fax:+86-532-482-5961

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