Chemistry : a 40% aqueous solution of sodium dimethyldithiocarbamate.

Typical use :  As a temporary preservative for green hides and skins.

How to use : Ideally, skins should be treated as soon as possible after flaying, to prevent staling damage before further processing begins.

For very short term preservation (up to 36 hours) a brief or momentary immersion of hides or skins in treatment solution is enough.  For longer term treatment, load hides or skins into processing vessel with treatment solution and rotate for one hour.

If holding times are increased, then :

• increase the Tecmate 100 dose rate
• add boric acid to the solution
• increase treatment time to one hour minimum, with agitation.

Dose rates are in the table below. Amounts are percentages.
Important  : These recommendations are based on total weight of hides or skins plus float.

Use the following minimum doses.
 

Preservation Time in days	Tecmate 100 Summer dose	Boric acid Summer dose	Tecmate 100 Winter dose	Boric acid Winter dose
1	0.2	0.2	0.2	-
2	0.2	0.4	0.4	-
3	0.3	0.5	0.25	0.5
4	0.4	0.7	0.3	0.6

For example :
1. To hold freshly flayed hides for 24 hours under winter conditions, make up a solution of 2 kilograms of Tecmate 100 per tonne of float and hides together.  Immerse the hides in this solution to fully wet them.
2. To hold hides for three days under summer conditions, load them into a processor. Add 3 kilograms of Tecmate 100 plus 5 kilograms of boric acid for each tonne of hides and float together.  Rotate processor for one hour.

After treatment, hides or skins may be left in the processor, with or without the treatment liquor, or dumped.  However, do not permit them to dry out.  Since the pH of the treatment liquor is high, they may go straight to liming without further treatment.

Tecmate 100 may be used as a soaking additive to prevent serious staling damage during wet back of salted stock. Minimum dose based on total hide or skin weight plus float is 0.03%.  More should be added for extended soaking times, or when temperatures are higher than normal.

Observe the details on the material safety data sheet (AU) and (NZ) for safe handling practice.

Chemistry :  96% dichlorophene in the form of a powder.

Typical use: This is used as a salting additive to replace napthalein, or to add extra power against red heat and purple heat bacteria.

How to Use : Mix with salt (sodium chloride) and boric acid before applying to skins or hides.  The minimum dose is 500 grams per tonne of skin/hide weight.

Observe precautions as detailed on the material safety data sheet.

Chemistry : a 50% active solution of sodium mercaptobenzothiazole, also called MBT. Traces of sodium hydroxide are also present.

Typical use :  Mercostop is a fungicide for pickled skins, and tanned leather, such as wet blues, wet browns and wet whites.

How to Use : Recommended addition point is with salt and before acid addition at the beginning of pickle. Mercostop prefers high pH.

For manual addition, pre-dilute with water, at least 10 to 1, and slowly add into the tanning vessel, over a five minute period.
For automatic addition, pump into the recirculating line over a five minute period.

Minimum recommended doses. (Sometimes local conditions, or longer protection periods require higher doses).
 

Pickled sheep or lamb pelts:  Wet blue ovine:  Wet blue bovine:  Vege tan bovine:

0.1% 0.35% 0.25% 0.4%

Note: these levels can be reduced significantly if a supplement such as Combigard is also used. It is vital that all doses be confirmed by full scale plant trials. Tantec staff will help with these. Tantec offers a tropical chamber service to evaluate trial results.

Advantages of MBT:

1. MBT is cost effective
2. Very effective at recommended doses against a wide range of fungi.
3. Good fixation to hides and skins. Resistant to leaching.
4. Low odour.
5. Low in toxicity.
6. Though corrosive in concentrate, produces low irritancy at use rates.
7. Biodegradable.
8. MBT will work well where some other fungicides fail due to incompatible chemical conditions. MBT works well even in greasy liquors.
9. Penetrates well, giving some protection of split surfaces.

1. Not as potent as TCMTB
2. Has some gaps in its spectrum of activity. See notes on Combigard below.
3. The concentrate contains small amounts of sodium hydroxide which means it is legally classified as dangerous goods - corrosive. The concentrate can irritate sensitive tissues if mishandled or swallowed.
4. If added in a region of low pH, Mercostop can cause white marks to appear on wet blue. If added as recommended, this is unusual. If this problem arises anyway, it is advised that dose levels be lowered. This can be accomplished with no loss of performance by also adding Combigard in the post-tan rinse. Check with your Tantec representative.

Please note the correct safe handling practice detailed on the material safety data sheet: Mercostop(AU), Mercostop (NZ).

Chemistry
A 30% active water based liquid containing  2-(thiocyanomethylthio)benzothiazole -also known as TCMTB.   Dermagard disperses readily in water to form an emulsion.  The special feature of Dermagard is that all solvents other than water have been replaced by a modified vegetable oil, rendering it odourless: a major advance over other TCMTB products, with their characteristic unpleasant pungent smell.

In addition, some reports indicate substantially reduced skin irritation compared to other water based or solvent based formulations.

Care needs to be taken with Dermagard in colder conditions.  Exposure to low temperatures may cause the formulation to thicken, making handling more difficult.

Use
Dermagard is a fungicide for pickled skins, and tanned leather in the wet state, such as wet blues, wet browns, and wet whites.

How to Use
Dermagard must be added at a stage when pH levels are low. It should be added very slowly.  Typical addition points are :

• In the pickle at least 30 minutes after acid addition
• In chrome tannage at least 30 minutes after chrome addition.  (Avoid addition 30 minutes before or after addition of Magnesium oxide)
• In the post tan rinse
• Any combination of the three points shown above.

For automatic addition, add the concentrate by slowly pumping it into a recirculating line over 10 to 20 minutes.

The following recommended doses are minimums.  Often, due to local conditions, or variable protection times, higher doses are required.

• Pickled sheep or lamb pelts.  0.035%
• Wet blue ovine    0.1%
• Wet blue bovine   0.075%
• Vege tan bovine   0.2%

TCMTB fixes mainly to the surface of hides and skins.  If these are later split, we recommend a separate treatment of split surfaces.

Advantages of TCMTB

• TCMTB is very potent. Quite low doses can be used.
• Reasonably cost effective. Superb performance at low pH.
• Tried and true.  Used for a long time, and proven.
• Rapidly and firmly fixes to hides and skins.
• Broad spectrum.  With a few exceptions, it controls most moulds.
• Not very toxic if swallowed.
• Biodegradable (Rapid in soil or water. Very slow if fixed to leather.)

Disadvantages of TCMTB

• TCMTB is broken down by a number of chemical agents. The presence of  sulphides, alkalis, oxidisers or reducing agents may make it less effective. This is a common cause of failure.
• Grease loving.  Liquors with high grease contents (eg. Recycled liquors) may remove TCMTB before it fixes to hides.
• Irritant.  TCMTB can cause rashes, and even burns on workers skin if handled carelessly, though this problem may be reduced with the Dermagard formula.
• Toxic if TCMTB aerosol is inhaled.
• A couple of serious gaps in its spectrum, especially Trichoderma - a mould that grows on wood, and is often brought into tanneries on wet pallets.

Use of Supplement
We strongly recommend the use of a supplement to increase performance.  Carbostop and Carbostop WB are  Tantec products based on carbendazim that work very well in conjunction with Thiostop WB.  In particular, Carbostop will prevent Trichoderma infection.

Please note the correct safe handling practice detailed on the material safety data sheet: Dermagard (NZ) and Dermagard (Aust).

Combigard is a new fungicide from Tantec.  It combines the well known and highly effective active ingredients : TCMTB and carbendazim.   While there is nothing new about this combination, Combigard is the first such product to use only solvents with ultra-low toxicity and irritancy.  The result is a water based formulation that lacks the unpleasant odour of most TCMTB products, and has a reduced skin irritancy.   Our aim is to offer a much more worker friendly fungicide, which is still able to control the widest range of moulds.

Advantages of Combigard

• Less irritant than other TCMTB products
• Can be used in post-tan rinse without serious worker problem
• Broad spectrum of activity
• Highly potent and effective
• Water based to minimize harmful environmental impact
• Very low odour
• Cost effective
• Like all water based products, it is non flammable.

• The product may thicken in cold weather, becoming difficult to pump and handle. This problem will be overcome by proper handling methods, as advised by Tantec.
• Like all other TCMTB products, even though Combigard is less irritant and corrosive, care needs to be exercised in handling.

Addition points may be :

• All added with pickle.
• All added in chrome tannage.  However, not within 30 minutes of the MgO addition.
• Two thirds added in either pickle or chrome tannage, and the final one third in post tan rinse.

The advantages of combining several fungicide actives are well known.  The combination of Mercostop and Combigard means three potent and effective fungicides combine to control a wide range of moulds. 

Many tanneries cannot use TCMTB in the normal way, since these fungicides interact with tannery chemicals (like sulphides) to cause TCMTB to break down.  The ability to add in the post tan rinse without serious worker irritancy problems is a major advantage.  Combigard will work very well in this situation, with a high concentration of both actives fixing to the surface of wet blues.  In combination with MBT as described above, the treatment leaves few, if any openings for mould attack.

Please note the correct safe handling practice detailed on the material safety data sheet: Combigard (AU) and Combigard (NZ).

Typical use: Fungicide enhancer for the leather industry.  This product increases the anti-mould potency of your fungicide treatment and also increases the spectrum of activity; permitting protection against mould species otherwise difficult to control.

How to use: This product should not be used by itself, but only in conjunction with another fungicide, such as Mercostop or Thiostop.

For production of wet blue leather, use at least 300 grams of Carbostop for each tonne of green hide or skin weight.  For pickled lamb or sheep skins, use at least 100 grams for each tonne slat weight.

Add the powder to pickle or tan liquors, at least two hours before the end of processing.

Please note the correct safe handling practice detailed on the material safety data sheet: Carbostop(AU) , Carbostop (NZ).