DE4036506A1 - Antimicrobial compsn. for protecting leather and synthetic leather - contg. di:halo-bis:thiadiazolyl:sulphoxide, providing long lasting effect without discolouration - Google Patents

Abstract

Antimicrobial compsn. for preservation of leather and synthetic leather contains, apart from auxiliaries and/or pigments, a bis-thiadiazolyl cpd. of formula (I) as active ingredients. In (I), X = Cl or Br. (I) is pref. present at 0.05-3 wt.%. USE/ADVANTAGE - (I) provide long lasting and reliable protection against bacterial and fungal attack. They do not discolour the material being protected, are safe to use (low toxicity, non-irritating to the skin); are absorbed/incorporated readily and are compatible with all methods of (synthetic) leather prodn. (I) are incorporated as solns. or finely-divided dispersions.

Description

The invention relates to antimicrobial agents for Preservation of leather and synthetic leather. You can in the leather and synthetic leather industry can be applied.

Microorganisms such as fungi (Ascomycetes, especially Protoascomycetes and Euascomycetes) and bacteria (e.g. Pseudomonads) Able to process leather especially during processing to attack the raw hide to the rawhide as well as in the finished state and due to permanent discoloration or so-called foul spots to diminish in quality or completely useless do. Fungi occurring on leather (e.g. Penicillium, Aspergillus) are also strong spore-formers and are therefore able to release a large number of spores into the air. These can be both trigger fungal attack on other materials as well be hazardous to human health.

For this reason, it is essential to use leather through appropriate Protect preservatives from microbial contamination (K.H. Rampart; Practice of sterilization, disinfection, preservation; Georg Thieme Verlag Stuttgart, New York, 3rd edition 1984, p. 352). In practice, this is done by adding more suitable ones antimicrobial agent in the production process of leather production. Depending on the spectrum of activity, these are either during the soft, the vegetable tanning liquor, but especially at the beginning chrome tanning, possibly also in several sub-batches, or added during the rinsing process.

So far, antimicrobial agents for leather conservation have been used mainly used products containing pentachlorophenol (PCP) what but not today for toxicological and ecological reasons is more possible. These funds are through modern microbicides such as B. 4-chloro-3-methylphenol, quaternary ammonium salts, dithio carbamates, thiocyanates (e.g. 2-thiocyanatomethylthio-benzothiazole- TCMTB), benzimidazole compounds (e.g. benzimidazole carbamic acid) methyl ester BCM), but especially through S, N compounds such as Octylisothiazolin-3-one and dichlorofluoride have been replaced (Das Leather, 4/88, 66-73).

These preservatives also have various disadvantages. So they either have only a limited spectrum of activity,  pull badly on the leather and burden it over theirs Residual content in the fleet the environment, require relatively high Use concentrations are incompatible with system parts of the Leather production (substrate, liquors, containers), too little stable, relatively toxic, discolor the leather or tax the cost of leather production due to its high active ingredient price. Other highly effective antimicrobial agents are high Gas phase effect, which is a great occupational hygiene burden which means people who work with leather.

Similar to leather, synthetic leather is also subject to a microbial Attack by fungi and bacteria, from mold infestation to leads to rotting. Those are particularly affected Materials that are under heavy stress with both spores and Germination as well as with additional nutrients for the micro organisms are exposed. This applies, for example, to Parts contaminated with skin perspiration covered with synthetic leather Upholstered furniture too.

In practice, therefore, synthetic leather is also increasingly being added Preserved antimicrobial.

The preservative and coating solution of the Top coat (skin coat) or the adhesive coat (tie coat) introduced. As a preservative for this purpose, that is Fungicide N- (fluorodichloromethylthio) phthalimide (fluorfolpet) known.

This active ingredient requires a technical preparation complex process and is therefore economically ineffective. It also hydrolyzes in aqueous solution and is therefore under the moisture promoting microbial growth relatively quickly degraded to ineffective secondary products.

The aim of the invention is to develop new antimicrobial preservatives to develop leather and synthetic leather that are effective, user-friendly and non-discoloring.

The invention has for its object new antimicrobial To provide agents with good compatibility with leather and synthetic leather. According to the invention, this object is achieved by  that the new agents as active ingredients thiadiazolyl sulfoxide general formula

in which X = Cl or Br. The antimicrobial Active ingredients are in addition to usual excipients and carriers Concentrations of 0.05 to 3 parts by mass in% in preparation forms contain a good mounting on leather or allow incorporation in synthetic leather. Such forms of preparation solutions (e.g. in organic solvents such as Dimethylformamide and / or toluene) or the finely ground active ingredients as dispersions in the liquors alone or in a mixture with known auxiliary, carrier and / or color pigments. The Active substances on which the agents according to the invention are based according to methods known from the literature [Z. Chem. 20, (1980), 370] Halogenation and subsequent oxidation of methylene bis (potassium cyanimidodithiocarbonate) can be produced. You are less toxic, skin-friendly, possess excellent complex bactericidal and fungicidal activity spectrum only a small gas phase effect, draw well on the leather or can be easily in Incorporate artificial leather and are compatible with all system parts of leather and synthetic leather production.

Embodiments

The invention is explained below using examples. In this the tested antimicrobial agents with the following Abbreviations:

B1 = 2-thiocyanatomethylthio-benzothiazole
B2 = combination of phenolic substances without pentachlorophenol
B3 = N- (fluorodichloromethylthio) phthalimide
B4 = p-chloro-m-cresol
E1 = (3-bromo-1,2,4-thiadiazol-5-yl) - (3'-bromo-1 ', 2', 4'-thiadiazole-5'-ylthiomethyl) sulfoxide
E2 = (3-chloro-1,2,4-thiadiazol-5-yl) - (3'-chloro-1 ', 2', 4'-thiadiazol-5'-ylthiomethyl) sulfoxide

The following bacteria and fungi were used as test germs:
I = Staphylococcuc aureus
II = Escherichia coli
III = Candida albicans
IV = Trichophyton mentagrophytes
V = Penicillium spp.
VI = Aspergillus niger
VII = mixed spore suspension of infected leather

Example 1 Testing the agents according to the invention against bacteria, Yeast and fungi in the agar diffusion test

Filter papers with a diameter of 20 mm were used for the test impregnated with 0.05 ml of the drug solution to be tested, then dried and on plane cast agar media (test germs I-II on nutrient storage, test germs III-VI on malt spice agar) hung up. Thereafter, the test sheets with 5 ml agar medium overlaid. After the agar medium had solidified, 0.1 ml was added the germ suspension was dropped and spatulated. After incubation cultures (test germs I-II for 24 hours at 37 ° C, Test germ III for 5 days at 22 ° C, test germ IV for 4 weeks at 22 ° C and test germs V-VI for 1 week at 22 ° C) the evaluation was carried out. The zones of inhibition were measured in mm. The results are shown in Table 1.

Table 1

Inhibition zone (in mm) of the tested active ingredients in the agar diffusion test

Example 2 Testing the agents according to the invention against leather destructive microorganisms

Of those heavily infested with microorganisms (fungi and bacteria) A mixed spore suspension (VII) was produced in leather. The further testing was carried out in the agar plate test.

On the one hand, the agents according to the invention were in concentrations of 0.05% and 0.1%, based on the active substance content, in the agar incorporated, after the agar has solidified with 0.1 ml of the Mixed spore suspension (VII) was inoculated. On the other hand the agents applied to filter paper, which is in the lid of the Petri dish was positioned. The infection also occurred using 0.1 ml mixed spore suspension (VII) on the agar. Means this experiment, the effect in the gas phase was determined. In addition to the natural microorganisms found on leather isolated strains of Penicillium spp. (V) as well Aspergillus niger (VI) included in the test.

The classification of the effect was based on the following guided schemes

1 = unhindered growth
2 = growth inhibited only slightly
3 = individual colonies pronounced
4 = no microorganism growth

Table 2 below shows the results of this Exam shown.

Table 2

Effect of the tested active ingredients on leather-destroying microorganisms

Example 3 Testing the agents according to the invention for antimicrobial Effectiveness in synthetic leather

For testing, 2 × 2 cm polyurethane compact synthetic leather samples were used used that according to Table 3 with antimicrobial Active ingredients had been equipped. These leatherette samples were used in analogy to Example 1 and with Germ suspensions inoculated with agar media and left there. The samples were then, as described in Example 1, incubated. The evaluation was carried out immediately after incubation and after 3, 6 and 9 months. Were measured the zones of inhibition in mm. The results are in Tables 4-7 shown.

Table 3

Antimicrobial synthetic leather samples

Table 4

Inhibition zones (in mm) of antimicrobial synthetic leather samples shortly after incubation

Table 5

Inhibition zones (in mm) of antimicrobial treated artificial leather samples after 3 months

Table 6

Inhibition zones (in mm) of antimicrobial synthetic leather samples after 6 months

Table 7

Inhibition zones (in mm) of antimicrobial synthetic leather samples after 9 months

Claims (2)

1. Antimicrobial agent for the preservation of leather and synthetic leather, characterized in that, in addition to known auxiliaries and / or color pigments, the compounds of the general formula as active ingredients in which X = Cl or Br is included. 2. Antimicrobial agents for preserving leather and synthetic leather according to claim 1, characterized in that the Active substances in concentrations of 0.05 to 3 parts by mass are included in%.