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Germicidal varnish

for better hygienic properties

In order to meet the hygienic demands in medically sensitive areas our VARIO models are equipped with a special varnish.

Contained in the varnish are micro particles of silver which deposit at the surface after apllying the varnish. Thereby germs can hardly spread out on the surface. The metabolism of bacteria is disturbed by exchange of potassic ions. They die off. Microbes are additionally killed by the exchange of sulfureous amino acids.

These hygienic characteristics were examined and confirmed by an independent institute.

Lacquer properties

1. Material description

The material used to produce the surface of the Viewmedic OP solutions is a two-component, polyurethane-based material resistant to chemicals, light and weather. Once cured, the surface exhibits no indications of yellowing or chalking even when exposed to severe weather conditions. It is also abrasion-resistant, elastic, insensitive to scratching and resistant to chemicals, brighteners, synthetic coolants, hydraulic oils and detergents.

2. Fields of application

The coating is used primarily for the final coating if the lacquer has to meet stringent requirements with regard to chemical and corrosion damage (see No. 5) or is exposed to severe weather conditions.

3. Colouring

RAL 7035 Light grey

4. Luster

Satin-finished

5. Chemical resistance to disinfectants

Procedure:

A piece of soaked cotton wool is placed on a dried, cleaned surface and covered with a Ø 80 mm watch glass. The test is performed over 72 hours at room temperature.
If readily volatile media, e.g. FREKADERM or FREKANOL are used, the cotton wool needs to be re-moistened.

The surface is assessed after being washed off with water.

Test criteria:

  • Does the coat of lacquer peel away? Do blisters form?
  • Is the surface matt or discoloured?
  • Is the surface cracked or porous/attacked?


Providing the aforementioned criteria are satisfied, especially with regard to peeling, attack or severe discolouration of the surface, the coating is to be categorised as "non-resistant".

If there is "no change" or only a "slight change" of two media in one group of active agents or of one medium in different groups, the coating or imprint is to be categorised as "resistant".

Wipe test:

In addition to the chemical spot test, the wipe test is carried out.
This involves using a paper tissue soaked in petrol or ethanol to make circular movements over the coloured surface or imprint for 15 seconds, normal pressure being applied.

No peeling, discolouration or turbidity of the lacquer and/or imprint may be evident after this period.

On using only surface disinfectants, the media group
Alcohol-containing FREKANOL(40%) undiluted
FREKADERM (80%) undiluted
MELISEPTOL undiluted
Tenside-containing Teta-S 1%-ig
Teta-clean undiluted
Aldehyde-containing Ultrasol F 1%-ig
Incidin perfekt 1%-ig
On using the aforementioned media and the disinfectants
Active chlorine-containing Sporotal 100 (4%) undiluted
Bleach (NaOCl 12%) undiluted 20 : 1
Active oxygen-containing Puristeril 340 undiluted
Peracetic acid 40% undiluted 10 : 1
Other Caustic soda 10 % undiluted 10 : 1
glycerine/water undiluted 1 : 1
Citrosteril (24%) undiluted 10 : 1

6 Hygiene report


The antimicrobial characteristics of the surface were verified in the suspension test in accordance with standard JIS Z 2801:2000.

6.1. Suspension test method

The test involves applying defined test bacteria suspensions of gram-negative and gram-positive bacteria species and yeasts. In order to bypass the influence caused by general material properties, the test is conducted in accordance with standard JIS Z 2801:2000. Bacteria and yeasts from the logarithmic growth phase are incorporated into a mineral-based solution with low peptone medium concentration and applied to the surface being tested. Following injection, the inoculum is covered with a sterile film, which distributes the micro-biological suspensions into a thin layer on the specimen. This guarantees a realistic test.

As a zero control, the bacterial count from one section of the samples is determined after 30 seconds of residence time.
The anti-microbial effect of the surface coating is determined from the bacterial count after the test preparations have bred at 37°C for 18 hours. If the initial bacterial count reduces by > 2 Iog10 stages taking into account the zero value, the anti-microbial property of the surface is categorised as a bacteriacide or fungicide when tested with fungi. If the bacterial count remains consistent, the surface is considered bacteriostatic or fungistatic when tested with fungi.

6.2. Test organisms and test bacteria concentration

Gram-negative bacteria:

  • Klebsiella pneumoniae MR-605971 1,0 x 104 cfu/ml

 

Gram-positive bacteria:

  • Staphylococcus aureus DSM 346 1,0 x 104 cfu/ml
  • Enterococcus faecium ATCC 6057 1,0 x 104 cfu/ml

 

Yeasts:

  • Candida albicans ATCC 10231 1.0 x 104 cfu/ml

6.3. Results

6.3.1. JIS Z 2801:2000, actual values (30 second residence time)
Klebsiella pneumoniae 1,4 x 104 cfu/ml
Staphylococus aureus 2,0 x 104 cfu/ml
Enterococcus faecium 1,1 x 104 cfu/ml
Candida albicans 1,0 x 104 cfu/ml
6.3.2. JIS Z 2801:2000, actual values (18h, 37°C)
Klebsiella pneumoniae0,5 x 107 cfu/ml
0,5 x 107 cfu/ml
1,3 x 106 cfu/ml
1,8 x 106 cfu/ml
Mean 0.3 x 107 cfu/ml
Log reduction: >2 Iog10-stage growth
Staphylococus aureus



steril
steril
steril
steril
Log reduction: 4 Iog10 levels

Enterococcus faeciumsteril
steril
steril
steril
Log reduction: 4 Iog10-Stufen
Candida albicans1,8 x 105 cfu/ml
1,9 x 105 cfu/ml
0,6 x 105 cfu/ml
1,8 x 105 cfu/ml

Mean 0,5 x 106 cfu/ml
Log reduction: 2 Iog10 level growth

Summary

  • The coating has an antibacterial, bactericide effect towards gram-positive exciters.
  • The coating exhibits no antifungal effect. Disinfection is still needed.

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 |  Last Update: 18.07.2016 08:21