Química Internacional para el Curtido S.L.

Theory

Information on the waterproofing process

Maeser Test

Maeser Penetrometer Test (ASTM 2099-70)

Determines the penetration and dynamic absorption of water. Standard primarily required in North America.

In this method, the leather sample is subjected to a bending process in a dilute solution of common salt and the number of bends (or flexures) required for the water to pass through the leather is determined. 15,000 flexures are the lowest standard value for good waterproofing. Frequently, the dynamic water absorption is also determined after 15,000 flexures or after penetration of the water.

If what we are looking for are type requirements of 40,000 cycles or flexures in the Maeser penetrometer with a water absorption less than or equal to 12%, a type 2 hydrophobic grease will be used: Emulsifier + dispersant polymer + neutral simple oil + Silicone.

To obtain superior results of 140,000 cycles or flexures with the Maeser penetrometer with a water absorption less than or equal to 10%, a type 3 hydrophobic grease will be used: Emulsifier + Reactive Polymer + Neutral Simple Oil + Silicone.

To obtain results similar to the previous ones but with a very high water vapor permeability (more than 8 mg / 50 cm2, for example), a type 4 hydrophobic grease will be used: Emulsifier + Reactive Polymer + Neutral Simple Oil + Reactive Silicone.

A good result in the water vapor permeability test is given by thin and slightly finished leathers; however, thick leathers with a very covering finish will give us markedly lower water vapor permeability values.

Unfortunately no correlation can be established between the Bally test method and the Maeser test. With the same leather, good results can be obtained with the Bally penetrometer and, under circumstances, bad with the Maeser test and vice versa. In general, the Maeser test can be considered the most severe test, since the intensity of the bending process is greater.

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Bally Test

Bally penetrometer test (DIN 53338 / EN 345 ​​4.45 / IUP 10)

It is used mainly in Europe. This method measures the time it takes for the water to pass through a test piece of leather as well as the dynamic absorption of the water from it. The specimen is fixed to two cylinders (one fixed and the other mobile in the direction of its axis and mounted with its axes in a horizontal position), so that it forms a channel with its ends closed by the cylinders. The test piece thus arranged is partially immersed in the water. Next, and by means of a motor, the movable cylinder is propelled back and forth with a harmonic movement. The amplitude of this movement can be varied according to the thickness and resistance of the leather to be tested. During the test, the dynamic water absorption of the test piece is additionally determined, for which the latter is weighed at defined intervals of time. Good water penetration times for a 1.8mm thick upper. for a reduction of the length of the free part of the specimen of 10% it is more than 6 hours. Very good times are more than 24 hours.

To obtain adequate results in the Bally penetrometer 4 hours before the penetration of the water, a type 1 hydrophobic grease will be used: Emulsifier + Neutral simple oil + Silicone.

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Hydrophobization theory

For a leather to be waterproofed, it is necessary that the surface of the fibers and, above all, the surface of the elemental fibers, be covered with elemental products. Most of these products are heterogeneous compounds and the hydrophilic fatty component can precipitate and deposit around the fiber without chemical bonding.

Document

You can download “Hydrophobization theory” in PDF format and in this way you can access the content without being connected to the internet.

Improvement of the homogeneity in the Nubuck Hidrofugado after the application of the fixative LT-36 of Codyeco

The application of the LT-36 fixative should logically bring us a reduction in the fastness values to both dry and wet rubbing. But we wanted to see how it affected in different proportions the waterproofing of articles manufactured to obtain waterproofed nubuck for safety footwear or other types of technical footwear.

Document

You can download “Improvement of the homogeneity in the Nubuck Hidrofugado after the application of the fixative LT-36 of Codyeco” in PDF format and in this way you can access the content without being connected to the internet.

The homogeneity in the waterproofing

During the years that we have been working to obtain waterproof articles, both the product supply houses and the tanneries themselves have always sought to obtain lower values of water absorption by the skin, longer passage times, reduce the penetration of water, etc.

Document

You can download “The homogeneity in the waterproofing” in PDF format and in this way you can access the content without being connected to the internet.