System solution for diaper manufacturer – CareMelt
Innovations can sometimes solve one problem and create two new ones for the customer. That is why, whether working alone or with carefully selected partners, Pulcra Chemicals is striving more and more to offer integrated system concepts – such as this one in the textile technology field.
If some babies feel more comfy in their diapers than others, this may well have something to do with the skin-friendly finish applied to the fiber web. In developing suitable lotions, Pulcra Chemicals has been able to combine both Cognis’ know-how from the body care sector with that of its own textile technologists – an ideal synergy which led to a successful new product launch in the diaper market in 2000.
CareMelt – manufactured in accordance with the requirements of the German Cosmetics Ordinance – is part of an overall concept implemented by the Pulcra Chemicals Textile Technology unit in cooperation with Cognis Care Chemicals and dermatologists of the skin biochemistry unit. With this concept, customers are provided a chemically and technically fine-tuned system offering maximum dermatological compatibility.
Introducing caremelts
A major issue with active cosmetic ingredients in finishes is the transfer onto the wearer's skin. It is obvious that at least part of the rather costly substances will either stay on the surface or the coverstock or even be transported into the absorbent core where it is wasted. This point, combined with our earlier considerations about the limited opportunity of a very small amount of finish to have a strong impact on the skin has recently lead to a new approach: The application of a large amount of a skin care wax on the top of the coverstock. Such waxes are designated with the term "lotion" in a number of patents. We prefer to use the word "caremelt" because it is a much more accurate description of what such materials actually are and look like.
Caremelts
- are compositions of cosmetic waxes which melt at least partially at body temperature and transfer onto the skin
- are applied at levels 10 to 50 times higher than finishes and are actually visible with the naked eye
- are applied as hot melts at temperatures ranging from 50°C to 80°C using specially optimized spray or slot applicators like the ones available for example from Nordson or ITW Dynatec
- are applied in a discontinuous way in order not to disturb the liquid aquisition functionality of diapers or other hygiene products. Stripes, or spirals, or spots are some of the possible forms of application.
Pulcra Chemicals Textile Technology's CareMelts (Belsoft® Care) are largely based on derivatives of natural oils and fats which are solid at room temperature, but are selected in such a way that they partially melt at temperatures around 35°C. Triglycerides, partial glycerides, fatty alcohols, fatty esters, ethers, or carbonates and fatty acids are some of the prefered building blocs for caremelts. They represent a very versatile class of molecules which can be tailored to exhibit a favorable melting profile (see Fig. below): Caremelts should stay solid and not migrate in the hygiene product during storage but melt and transfer readily onto the skin when the hygiene product is used.
Finishes have a prime function as hydrophilic/hydrophobic surfactants. Caremelts are added on the top of the finish coating and do not need to be formulated to promote liquid acquisition although they do have a certain influence. They can be optimized with a prime focus on the enhancement of the skin barrier. Additionally they are an obvious and better second potential vehicle for active ingredients. The compatibility and stability issues we have discussed in relation with finishes do of course still need to be considered.
Another issue is becoming important with the introduction of caremelts: interaction with the hotmelt adhesives used to laminate the coverstock onto the absorbent core or the underlying acquisition layer. The fatty nature of most caremelts and their sheer amount exacerbate the risk of losing adhesion and may jeopardize the hygiene product integrity. This was the incentive for our active cooperation with Henkel Adhesives. The aim is to offer a high performance combination of caremelts and caremelt resistant hotmelts (Carebonds).
Outlook
It's just the beginning! As time passes, a growing number of sophisticated hygiene products including caremelt technology will be appearing on the market place. It is quite likely that the usage of caremelts will become a standard. Their distribution on the topsheet or other construction parts of hygiene products will become increasingly sophisticated. Their efficiency against diaper rash will be continuously enhanced. More advanced screening approaches will improve the differentiation capability between the good and the better. They will allow the development of optimized packages of care waxes and active ingredients. And you will see Pulcra Chemicals Textile Technology playing a very active role.
