support 713

 

Faq(Frequently Asked Questions)

 

What precautions are advisable when using crosslinkers?

In general, all chemical crosslinkers are to be used following important safety precautions. Avoid direct contact with skin when using. Use impermeable rubber gloves. Do not breathe vapors. Use the product only in well-ventilated areas, possibly using respiratory protection.

 

How are leathers to be dried after a crosslinked mixture?
The drying of the leathers after topcoat application must be very accurate, because the crosslinker incorporated in the film and then applied on the leather is sensitive to air humidity. If the leathers are dried well with a hairdryer after fixing, all the crosslinker is used for increasing the physical characteristics of the leathers. On the other hand, if dried naturally, the leathers will have slightly reduced performances because part of the crosslinker is neutralized by the humidity in the air. However, the performances will be better than any fixing agent without crosslinkers.

 

How long does it take for the crosslinking process to complete?
Once the topcoat with the crosslinker has been applied to the leather and dried, the action of Crosslinker 86 will gradually increase general resistances (in particular the wet and rub resistance). This is normally completed within 48-72 hours.

 

How are crosslinkers be added to the mixture?
The dosage and the way the crosslinker is added to the fixing agent needs very careful attention, it should be added slowly and while stirring to avoid a too fast reaction with the topcoat. A very efficient and easy to use crosslinker is Crosslinker 86. This is particularly appreciated for its crosslinking with water-based topcoats. For correct use, we suggest the following simple rules: - Crosslinker 86 is added to the topcoat at the moment to be used in a ratio of about 10% in weight. - Add slowly whilst stirring to be sure of a perfect dispersion of the crosslinker in the fixing agent. Crosslinker 86 is formulated with suitable solvents for a rapid and efficient homogenization of the mixture ready for use. Therefore, no pre-dilution is required, when it is added to fixing agents, whereas it is diluted if used with Adhesion Promoter. 

 

Why must a mixture containing crosslinkers be used within 8 hours?
This involves highly reactive molecules, dissolved in inert solvents that start to react as soon as they are added to the topcoat: thus obtaining better results in a quicker time. On the other hand, it also means that the topcoat with crosslinker must be used within a short time, usually 8 hours, otherwise this creating of 'bridges' increases viscosity until it is unusable.

 

Why use crosslinkers?
The actual requirements for the fastness of finished leather, such as its rub resistance and wet or abrasion resistance, impose the use of 'crosslinking' chemicals, that when added to either water- or solvent-borne topcoats, incredibly increase performances.

 

What are crosslinkers?
Crosslinkers are complex organic molecules able to set up chemical links between the molecular chains of the polymers that make up the topcoat film deposited on the leather. We add the crosslinkers to our products before spraying them, this froms 'bridges' that anchor the product's molecules between themselves and the leather, very much increasing the rub resistance properties. In more correct terms, this reaction starts a tri-dimensional complex that dramatically increases the mechanical properties of the film, such as surface hardness, toughness, flex resistance. Furthermore, crosslinking reaction reduces and even removes the presence of water sensitive hydrophilic functional groups in the polymeric structure which results in a significant reduction in water sensitivity, therefore a greater improvement in wet rub fastness.

 

When is good adhesion necessary?
This problem can arise even during the touch-up of a leather article. This is particularly so when working on a leather that has already been finished; it is always necessary to check that the products adheres well to the previous finishing. Older finished leathers can present various problems of adhesion due to dirt, grease or poor finishings. To avoid inconveniences it is necessary to check adhesion after application of each product, especially after the first coat and after having cleaned the leather.

 

How can I check the adhesion?
To check adhesion, all you need is transparent adhesive tape (the wide version is best). Stick it well to the top surface of the leather, once completely dry from at least 4 hours. Remove it quickly and look to see if any color has been removed. In this case, adhesion is too poor, so it is necessary to start again from the beginning.

 

How can I obtain good adhesion?
If the adhesion of the leather is not sufficient, it is necessary to use a specific product on the leather as a first step. One coat of Adhesion Promoter diluted, and crosslinked is normally sufficient enough to proceed with good results.

 

 

S5 Box

Login

Register

*
*
*
*
*
*

Fields marked with an asterisk (*) are required.

Search

Fenice Care System site use cookies to improve and personalize your experience and to display advertisements. The site may also include cookies from third parties. By using this site, you consent to the use of cookies.