Re: Quaternary ammonium salt - Didecyldimethyl ammonium chloride

[Kathy Francis <Franciskathy@xxxxxxx>]

In a message dated 6/11/07 8:15:42 AM, karin.vonlerber@xxxxxxxxxx writes:

> Dear Colleagues,
> together with a team of 5 textile conservators we will have to treat all
> church textiles from an important baroque church in Switzerland, amongst
> others 45 antependia. Due to bad air circulation, the annex in which the
> textiles have been kept fostered a quite serious mold outbreak in some
> cupboards and on some of the objects. The building shell and cupboards
> will be changed (this is not part of my question). We have been asked to
> do an interventive conservation treatment on all 45 antependia, all of
> them still mounted on their wooden strainers, all of them very dirty.
> The mold expert contracted by the monument preservation department has
> been working in the field of heritage preservation for a very long time.
> When discussing possible treatment options with regard to their effect
> of promoting a future mold outbreak, we were told to use a quaternary
> ammonium salt (didecyl dimethyl ammonium chloride) in a last rinsing
> bath. This specific quaternary ammonium salt - we were told - was the
> most pure form of the group and therefore used in heritage preservation.
> As this biocide is similar to a detergent, will bond like a substantive
> dye to the surface of a textile, and - just by my non-specialist
> guessing from the chemical description on the data sheet - seems to be
> very reactive, I am a bit hesitating. Even more so when - in spite of
> the suggested widespread use - we could find hardly any published
> research on the long term effect of quaternary ammounium salts on wool,
> silk, linnen etc. In CAMEO we did find a descriptive entry, but nothing
> in regard to the effect on objects. The only article I found (on AATA) is
> "Johnson, D.G. and Reagan, B.M.
> Influence of antimicrobial agents on dye fading and fiber yellowing in
> nylon.
> Textile chemist and colorist 22, no. 4 (1990 Apr), pp. 2124 [English]".
> In the abstract they state that: "The quaternary ammonium
> salt/organo-tin and phenol mixture caused the greatest color change in
> the dyed and undyed nylon."
> This does not make me less hesitant, to be honest.
>
> Does anybody have unpublished research on the effect of quaternary
> ammonium salt or could direct us to further published research? What
> other options could you suggest?
>
> The original intent of the conservator in charge of this project was:
> thorouhly surface clean with aspirator (HEPA-filtered)
> take off the wooden strainer
> wetclean
> Remount. (This originial proposual is under review and will most
> probably be modified; this is not the aspect of the treatment I would
> like to discuss here.).
>
> During this suggested treatment, the amount of spores is expected to be
> reduced by exponentials as well by vacuuming as by wet cleaning with a
> detergent. However, I am worried that during wet cleaning and while
> drying, remaining, dormant spores might be activated (it can take days
> until the fibre has really reached moisture equilibrium content again,
> even though the textile seems "dry"; and traces of remaining detergent
> may act as activator as well). I therefore suggested drying the object
> between two layers of blotting paper, the lower one being sprayed with
> 70% Ethanol, which would seep through the textile. 70% Ethanol is not
> *really* a biocide, as it is not 100% effective, however the amount of
> living spores can again be reduced quite drastically. (this I conclude
> from "Mary-Lou Florian: Fungal Facts, London 2002.)
> This suggestion of Ethanol then lead to the mold specialist's proposal
> of quaternary ammonium salt treatment, as in his view, Ethanol is not a
> biocide.
>
>
> Any ideas, reflections, and especially experience you could share is
> most welcome.
> Is there maybe an alternative to quaternary ammonium salt providing the
> same biocidal effect?
>
> Sincerely,
> Karin
> --
> Karin von Lerber
> Prevart GmbH
> Oberseenerstr. 93
> CH-8405 Winterthur
> Tel. +41 (0)52-233 12 54
> Fax. +41 (0)52-233 12 57
> e-mail: karin.vonlerber@xxxxxxxxxx
> www.prevart.ch


Karin

I have no experience with the question about quaternary ammonium salt but have a treatment experience with ethanol that may be of interest. Some years ago I treated a textile that had very active fungal growth using a 70% Ethanol solution in the final step before drying.

A roof leak had gone unnoticed and the textile had been wet for some time. It was Indian embroidery, with silk embroidery stitches covering cotton ground fabric almost completely. There was flourishing fungal growth— white, green, and black colored types with velvety texture.   Because there were numerous related problems (much dye bleed and stiffened stains) and positive response to cleaning tests the treatment plan included wet cleaning.

Just a partial sketch of the treatment from memory:   The types of fungi were not identified but testing before treatment was done to assess fungal activity.   This was done with simple biologic-type sterile nutrient pads (wort medium). The pad with sample from the object showed very significant growth (all 3 colors mentioned) on the pad after about 4-5 days, while the control pad had none.   

The textile was vacuum cleaned repeatedly then washed (deionized water, Orvus WA Paste, probably 3-4 rinses). I know that it is sometimes said that it is possible that the cleaning alone may have been enough to rid the textile of the fungi (Unfortunately I did not take a sample at this point to test growth).   After draining and blotting, a solution of 70% ethanol was repeatedly sprayed over the textile to saturate it.   Drying w/ cloth covering. After drying the fungal activity was again assessed using the wort nutrient pads—Nothing grew on the pads. 
My references for this were a short instructional sheet, “Assessing the Activity of Fungal Growth on Art Objects with A View To Possible Fumigation”, by paper conservator Hanna Szczepanowska and CCI Technical Bulletin #12,   “Controlling Museum Fungal Problems” by Thomas J. K. Strang and John Dawson.

Sincerely,
Kathy Francis
Francis Textile Conservation
FrancisConservation@xxxxxxxxxxx


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