DE4036507A1 - Aq, polymer dispersion contg. antimicrobial agent - comprising 1,2,4-thiadiazole sulphoxide or sulphone deriv. - Google Patents

Abstract

Aq. polyvinyl acetate or polyacrylate dispersions, and paints based on them, contain an antimicrobial thiadiazole deriv. of formula (I): X = Br or Cl; n = 1 or 2; R = phenyl or 3-X-1,2,4-thiadiazol-5-ylthio. (I) are described in DD 222770 (as plant-protective fungicides). The dispersions contain 0.01-3 (esp. 0.05-0.5) wt.% (I) in finely divided form, e.g. as a wettable powder. USE/ADVANTAGE - (I) act as preservatives for the dispersions and protect the paint films from microbial attack. They have comparable activity to known microbicides, e.g. benzisothiazol-3-one, have good stability, have low toxicity and are ecologically safe at the concns. used. In an example, a polymer dispersion (unspecified) contg. 0.1% 3-chloro-5-benzylsulphonyl- 1,2,4-thiadiazole remained free of microbial contamination after storage in a dish at room temp. for 3 months.

Description

The invention relates to antimicrobial aqueous synthetic resin dispersions based on polyacrylate or polyvinyl acetate and paints made from them. It can be used both for preservation of the dispersions themselves as well as to protect them produced paint films applied before microbial attack will.

Aqueous dispersions of synthetic resins used as dispersion paints have great economic importance both to ensure stability during storage up to Application as well as to avoid microbial, especially fungal Attacks on the additive's generated paint films suitable antimicrobial agents. This affects during the Storage predominantly a bactericidal effect in the aqueous Phase and then predominantly a fungicidal effect in the solid paint film. Only a few meet these requirements Substances.

It is known for these purposes as an antimicrobial additive Benzisothiazolon- (3) to use. This substance is very good effective, but technically difficult to access and uneconomical. The use of dithiocarbamates and thiuram is also known. However, they are only sufficiently effective at high concentrations and affect the ability to be painted over with drying oils or alkyd resins negative.

Volatile substances such as aldehydes are not long-lasting, phenols are too toxic or smell intensive and organic tin compounds are not suitable for indoor use due to their high toxicity.

Attempts are also known to address these shortcomings by combinations to counteract active substances. (DD-PS 1 07 848 and DD-PS 2 33 941). However, one only achieves sufficient storage stability, however insufficient film stability.

It is also known that part of the invention antimicrobial additives based on active ingredients their fungicidal activity against phytopathogenic fungi as plant protection products has been proposed (e.g. DD-PS 2 22 770). Here  has an effect especially against harmful fungi from the group of Oomycetes, especially against Phytophthora infestans, detected.

The aim of the invention is to find a suitable antimicrobial and less toxic addition to aqueous synthetic resin dispersions and to find paints formulated with it both good preservation of the dispersions as well reliable protection of the paint films made therefrom microbial attack is to be achieved.

The object of the invention is to create new antimicrobial to develop equipped aqueous synthetic resin dispersions. This object is achieved in that aqueous Synthetic resin dispersions based on polyvinyl acetate or polyacrylate and paints made from them, which in themselves contain known additives (e.g. pigments) as antimicrobial Active component substituted thiadiazoles of the general formula

in which X = Br or Cl
n = 1 or 2
and R = phenyl or

mean inflicted will.

The active ingredients can be according to methods known from the literature by halogenation and subsequent oxidation of the corresponding Prepare cyanimidodithiocarbonic acid monoester salts (e.g. U.S. Patent 37 36 328; Z. Chem. 20, (1980), 370). They are the resin dispersions added and are already in concentrations of 0.01% by mass effective. For practical purposes of Preservation and equipment are concentrations of 0.05-0.5 Mass proportions in% depending on the load on the paint recommend.

To ensure storage stability, 0.05-  0.1 mass percent in%, while for film stabilization each according to the desired long-term effect and the presence of germs 0.1-0.5 mass fractions in% are used.

The active ingredients can be used to achieve optimal distribution in the medium finely ground, e.g. B. wet fine grinding, pasted with Water and be combined with surfactants.

The active ingredients are stable, less toxic and influence the Ecosphere not negative under the conditions of use.

Embodiments Example 1 Examination of the aqueous synthetic resin dispersion for sterility Experiment description

The technical dispersion is with the specified concentration of the active substances to be tested mixed. Then one Take a sample (1 ml) and place it in a flamed, with Sabourand Culture medium (I) and in parallel with thioglycolate culture medium (II) filled test tube.

The samples with culture medium I are incubated for 10 days at 22-24 ° C and those with culture medium II for 10 days at 30-32 ° C in the incubator. The assessment is then carried out. The results are summarized in Table 1. Here means
+ without microbial infestation
+/- hardly any microbial infestation
- microbial infestation

Table 1

Evaluation of the resin dispersion for sterility

Example 2 Storage test of the aqueous synthetic resin dispersion Experiment description

1 kg synthetic resin dispersion is with the specified concentration of the active substances to be tested and mixed in a test glass Stored at room temperature.

The assessment of microbial infestation is carried out monthly according to the following rating scheme
1 = no infection
2 = weak infestation
3 = severe infestation
The results are shown in Table 2.

Table 2

Microbial infestation of stored synthetic resin dispersions

Example 3 Testing the film stability of the paint film Experiment description

Paint carriers made of filter paper are coated with the synthetic resin dispersion to be tested. The dried films are placed in petri dishes made from mineral salt or nutrient agar and each sprayed with a spore suspension of Penicillium funiculosum (A) Pullularia pullulans (B) and Aspergillus niger (C). This is followed by a 6-week incubation in an incubator at 25 ° C with weekly assessment of growth according to the following rating scheme
1 = overgrown
2 = medium growth
3 = weak vegetation
4 = no vegetation
The test results are summarized in Table 3.

Table 3

Fungal growth of the paint film

Claims (2)

1. Antimicrobial aqueous synthetic resin dispersions and paints thus formulated based on polyvinyl acetate or polyacrylate, characterized in that, in addition to auxiliaries and additives known per se, substituted thiadiazoles of the general formula as antimicrobial active components in which X = Br or Cl
n = 1 or 2
and R = phenyl or means
contain. 2.Antimicrobially treated aqueous synthetic resin dispersions Claim 1 characterized in that the antimicrobial Active component in concentrations of 0.01-3 parts by mass is included in%.