DD291343A5 - ANTIMICROBIAL MEANS FOR PRESERVING LEATHER AND LEATHER - Google Patents

Abstract

The invention relates to novel antimicrobial agents for preserving leather and artificial leather, which contain thiadiazolylsulfoxides substituted as active ingredients. By means of the present invention, a reliable and long-lasting protection of the leather and synthetic leather goods equipped therewith against microbial infestation is achieved. bactericidal and fungicidal action; preservatives; Leather; Leatherette; substituted thiadiazolyl sulfoxide}

Description

Field of application of the invention

The invention relates to antimicrobial agents for preserving leather and artificial leather. It can be used in the leather and art loader industry.

Characteristic of the known technical solutions

Microorganisms such as fungi (Ascomycetes, especially Protoascomyceten and Euascomyceten) and bacteria (eg · Pseudomonas) are able to attack leather both during processing, especially from the rawhide to the rawhide and in the finished state and by permanent discoloration or so-called fouling in to degrade the quality or render it completely useless. Leather fungi (eg, Penicillium, Aspergillus) are also strong spore formers and thus able to release a large number of spores into the air. These can cause a fungal attack on other materials as well as being harmful to human health.

For this reason, it is indispensable to protect leather from microbial attack by suitable preservatives (K.H.

Wallhäußer; Practice of sterilization, disinfection, preservation; Georg Thieme Verlag Stuttgart, New York, 3rd edition 1984, p.352). In practice, this is done by adding suitable antimicrobial agents in the production process of leather production.

Depending on the spectrum of action, these are added either ntweder during the turnout, the vegetable tanning liquor, but above all at the beginning of the chrome tanning, optionally also in several part lots, or during the rinsing process.

Up to now pentachlorophenol-containing products (PCP) have mainly been used as antimicrobial agents for leather preservation, but this is no longer possible today due to toxicological and ecological green tones. These agents are enhanced by more modern microbiocides, e.g. 4-chloro-3-methylphenol, quaternary ammonium salts, dithiocarbamates, thiocyanates (ζ. Β.

2-thiocyanatomethylthio-benzothiazole-TCMTB), benzimidazole compounds (eg Benzimidazolcarbaminsäuremethylester BCM), but especially by S, N-Verbirrdungen such as octylisothiazolin-3-one and Dichlofluanid been replaced (Das Leder, 4/88,

These preservatives also have various disadvantages. So they either have only a limited spectrum of activity, bad on the leather and thus burden on the residual content in the fleet the environment, require relatively high Ensatzkonzentrationen, are incompatible with system parts of leather production (substrate, fleets, containers), too little stable, relatively toxic discolor the leather or increase the cost of leather production by their high drug price. Other highly effective antimicrobials have a high gas phase effect, which represents a major occupational hygiene burden on those working in leather processing.

Similar to leather, synthetic leather is also subject to microbial attack by fungi and bacteria, which leads from mildew to rotting. Of particular concern are those materials that are subject to heavy exposure to both spores and germs as well as additional nutrients for the microorganisms. This is the case, for example, for parts of leatherette-covered upholstered furniture contaminated with skin sweat.

In practice, artificial leather is therefore increasingly conserved by the addition of antimicrobial agents.

The preservative is incorporated into the coating solution of the topcoat (skincoat) or the tie coat (Tiecoat). As a preservative for this purpose, the fungicide N- (fluorodichloromethylthio) phthalimide (Fluorfolpet) has become known.

This active ingredient requires a technically complicated process for its preparation and is thus economically ineffective.

In addition, it hydrolyzes in aqueous solution and is therefore degraded under the microbe growth promoting moisture relatively quickly to ineffective secondary products.

Object of the invention

The aim of the invention is to develop new antimicrobial agents for preserving leather and artificial leather, which are effective, user-friendly and non-discoloring.

Explanation of the essence of the invention

The invention has for its object to provide new antimicrobial agent with good leather and Kunstlederverträglichkeit. This problem is solved eiflndu.igsgemäß that the new MiUeI as active ingredients Thiadiazolylsulfoxide the general formula

where X = Cl or Br means. The antimicrobial agents are in addition to conventional excipients and carriers in concentrations of 0.05 to 3 parts by mass in% contained in preparation forms that allow a good mounting on leather or incorporation into synthetic leather. Such forms of preparation may be solutions (e.g., in organic solvents such as dimethylformamide and / or toluene) or the finely-milled actives as dispersions in the liquors alone or in admixture with known auxiliary, carrier and / or color pigments. The active substances on which the agents according to the invention are based can be prepared by literature methods (Z. Chem. 20, [1980], 370) by halogenation and subsequent oxidation of methylene bis (potassium cyanimidodithiocarbonate). They have low toxicity, are tolerated by the skin, have a low gas phase effect with an excellent complex bactericidal and fungicidal spectrum of action, absorb well on the leather or can be easily incorporated into artificial leather and are compatible with all parts of the leather and artificial leather production system.

exemplary

The invention will be explained below by way of examples. Therein the tested antimicrobial agents are designated with the following abbreviations:

B1 = 2-thiocyanatomethylthio-benzothiazole

B2 = combination of phenolic drugs 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'-thiadiazol-5'-ylthiomethyl) -sulfoxide E2 = O-chloro I ^ Athiadiazol B y D-O'-chloro-V ^ '^' - thiadiazole-B 'ylthiomethyD sulfoxide

The following bacteria and fungi were used as test germs:

I = Staphylococcus aureus

II = Escherichia coli IiI = Candida albicans

IV = Trichophyton mentagrophytes

V = Penicillium spp.

VI = aspergillus niger

VII = mixed spore suspension of infested leather

EXAMPLE 1 Testing of the Antibacterial Agents Against Bacteria, Yeasts and Fungi in the Agar Diffusion Test For the test, 20 mm diameter filter discs were impregnated with 0.05 ml of the active substance solution to be tested, then dried and poured onto flat-cast agar media (test organisms Ml on nutrient agar, test organisms Ill -Vl auff Malzwürzagar). Thereafter, the test papers were overlaid with 5 ml of agar medium. After solidification of the agar medium in each case 0.1 ml of the germ suspension was added dropwise and spatulated. After incubation of the cultures (test germs l-ll for 24 hrs. At 37 ⁰ C, test germ III for 5 days at 22 ° C, test germ IV for 4 weeks at 22 ⁰ C and test bacteria V-Vl for 1 week at 22 ⁰ C. ) was the evaluation. The homosexual zones were measured in mm. The results are shown in Table 1.

Table 1

Inhibition zones (in mm) of the tested materials in the agar diffusion test

active substance Conc. (%) I Il III test organisms V Vl IV According to the invention: 20 1 6 2 1 E1 0.1 18 1 7 10 2 2 E2 0.1 8th known: 14 2 7 2 4 B3 0.1 1

EXAMPLE 2 Testing of the Agents According to the Invention Against Leather-Destroying Microorganisms A mixed-spore suspension (VII) was prepared from leather heavily infested with microorganisms (fungi and bacteria).

The further examination was carried out in the agar plate test.

The compositions according to the invention were incorporated into the agar in concentrations of 0.05% and 0.1%, based on the active substance content, and 0.1 ml of the mixed spore suspension (VII) was inoculated after the agar solidified. On the other hand, the funds were applied to filter paper, which was positioned in the lid of the Petri dish. The infection took place

also by means of 0.1 ml Mischsporensuspensiori (VII) on the agar. By means of this experiment the effect in the gas phase was determined. In addition to the natural microorganisms found on leather, isolating strains of Peniciiiium spp. (V) and Aspergiiius niger (V) were included in the audit. The classification of the effect was based on the following scheme

1 = unhindered growth

2 = growth only slightly inhibited

3 = single colonies pronounced

4 = no microorganism growth

Table 2 below shows the results from this test. Table 2 Effect of the tested active ingredients on leather-destroying microorganisms

medium Konz.AS (%) Contact action V Vl rating V Vl VII 4 4 4 4 known: 4 4 4 Gas phase effect 4 4 B1 0.1 4 4 4 VII 4 4 0.05 4 4 4 4 4 B2 0.1 4 4 0.05 4 4 4 3 2 According to the invention: 4 4 4 4 2 2 E1 0.1 3 4 4 4 2 3 0.05 4 4 4 2 2 E2 0.1 4 2 0.05 1 2 1

Example 3: Testing of the agents according to the invention for antimicrobial effectiveness in artificial leather For the test, 2 cm × 2 cm polyurethane compact synthetic leather samples were used which had been equipped with antimicrobial active substances in accordance with Table 3. These synthetic leather samples were applied to the agar media used as in Example 1 and inoculated with germ suspensions and left there. Subsequently, the samples were incubated as described in Example 1. The evaluation was performed immediately after incubation and at 3.6 and 9 months. The zones of inhibition were measured in mm. The results are shown in Tables 4-7.

Table 3 Antimicrobially finished artificial leather samples Sample drug conc. (%) Equipment

a without - - b B3 0,125 in the top coat C B3 0.25 in the top coat d B3 0.25 in the adhesive line θ E1 0.25 in the top coat f E1 0,125 in the top coat G E1 0.25 in the adhesive line H E2 0.25 in the adhesive line i E2 0.25 in the top coat

Table 4 Retention zones (in mm) of antimicrobially treated artificial leather samples shortly after incubation

Sample Test Germs I U JII IV V Vl_

a 0 0 0 0 0 0

b '2 0 1 10 0

c 3 0 110 2

d 2 0 110 1

e 9 13 3 13

f 4 0 12 11

g 6 0 2 10 1

h 7 0 2 111

i 8 13 2 13

Table 5 Inhibition zones (in mm) of antimicrobially treated artificial leather samples after 3 months

sample I Il III test organisms V Vl 0 0 0 IV 0 0 a 2 0 1 0 0 0 b 3 0 2 1 0 0 C 2 0 1 1 0 1 , d 10 1 3 1 2 2 e 4 0 1 3 1 2 f β 0 2 1 0 1 G β 0 2 2 0 1 H 9 1 3 1 2 2 i 2

Table β

Retention zones (in mm) of antimicrobially treated artificial leather samples after 6 months

sample I Il III test organisms V Vl 0 0 0 IV 0 0 a 2 0 1 0 0 0 b 3 0 1 0 0 1 C 1 0 1 1 0 1 d 8th 1 2 0 1 2 e 3 0 1 2 1 1 f 5 0 1 0 0 1 G 6 0 1 1 1 1 H 8th 1 2 1 1 2 i 1

Table 7 Retention zones (in mm) of antimicrobially finished artificial leather samples after 9 months

sample I 0 Il III test organisms V Vl 1 0 0 IV 0 0. a 3 0 0 0 0 0 b 1 0 1 0 0 2 C 7 0 0 0 0 0 d 3 0 2 1 1 2 e 2 0 1 2 1 1 f 3 0 1 1 0 1 G 8th 0 1 1 1 1 H 0 2 0 1 1 i 2

Claims (1)

1. Antimicrobial agents for preserving leather and artificial leather, characterized in that sieneben known excipients and / or color pigments as active compounds of the general formula • ¹ ^ S ' ¹ ' - SOGH ₂ S where X = Cl or Br is included.
2. Antimicrobial agents for preserving leather and artificial leather according to claim 1, characterized in that the active ingredients are contained in concentrations of 0.05 to 3 parts by mass in%.