2. Outline of durable, hydrophilic SR agent

Figure 1 Example of durable, water absorbent SR agent structure

Some proposals are indicated in Figure 1. First of all, for the skeletal, principal chain structure of polymer, a selection should be made from the vinyl group, water-absorbent silicone, isocyanate (urethane), polyester polymer, polyamide, fluorocarbon polymer and the epoxy group in order to attain hydrophilicity to the fullest extent possible. The structure then is bound, combined, or reacts with another hydrophilic group, for which the incorporation of a cross-linking group or a hydrophilic moisture-retentive component will work effectively.

In general, as hydrophilic groups there are ethylene glycol, diethylene glycol, triethylene glycol, alkylene oxide polymer, PEG, PPG, PEG block polymer, polyether, glycerin, sorbitol etc.
For uses also as a cross-link, both end-terminal groups of chemical compounds should take the form of the vinyl, glycidyl or allyl groups before application.
Squalane, chitosan, hyaluronic acid, collagen, sericin, natural protein, cellulosic substances and thickeners are regularly used as moisture-retentive components.

- Hydrophilic vinyl-polymer in Figure 1 Various devices will be possible based on Figure 2-1, which shows an example of incorporating an acrylic acid copolymer to each hydrophilic group. Durability will be added and stains can be removed easily. Chemicals listed have been long used as bases for practising anti-staining techniques.

- Water-absorbent silicone which carries reactive groups already possesses in its structure cross-linking and hydrophilic properties and is also capable of producing soft hand. Since it can cross-link with other hydrophilic groups, it is highly valued for use in a durable, water-absorbent finishing agent or as an SR agent (see Figure 1 and Figure 2-2).

Figure 2 Examples of durable, water-absorbent SR agent

- By incorporating an etherizing compound, a polyether, alkoxylating compound to diisocyanate, polyurethane with high hydrophilic properties can be obtained. It is a very interesting cross-linking polymer which allows the formation of a highly durable polymer by cross-linkage between hydrophilic groups and polyurethane, binding of fluorine alcohol, as shown in Figure 2-3, or copolymerizing of hydrophilic vinyl groups.

- Since a hydrophilic polyester resin polymer skeleton is one that displays highest affinity to polyester, it is used as a base in a wash-fast & water-absorbent SR agent for polyester in the form of polymer such as PEG with improved hydrophilic properties. Nowadays, it is often used as a high function compound, bound or mixed with melamines, cationic silicones, block isocyanates, and hydrophilic group compounds as shown in Figures 1 and 2-4.

- As fluorine groups are fundamentally based on acryl or methacrylic acid type vinyl groups, they are often copolymerized, as shown in Figures 1 and 2-5, with:

• diisocyanates (urethane adducts)
  
• hydrophilic groups (PEG with cross-linking group)
  
• acrylates, vinyliden chlorides etc

or, their adhesive properties can be strengthened with fluorine alcohol, amide and PEG, or cross-linking resin polymer, their use is highly valued as oil-release properties can be attained from a hydrophilic group, and oil-repellency from a fluorine-group chain.

- Polyamide polymer and epoxy polymer are convenient polymer groups that allow a wide range of applications such as below.

• Incorporation of a hydrophilic group using carboxylic acid
  
• Use of an epoxy grouop as a cross-linking agent
  
• opolymerization with a functional polymer
  
• Use as an interactive cross-linking

Although the above is an overview that would only scratch the surface, crucial basics have been included.

In the following chapters 3 and 4, a description of the products, developed based on our long-accumulated research data, will be given with references to Figures 1 and 2.