Here is some ingredient info:
Raw Materials
Conditioning agents
Early fabric softener formulas were relatively simple dispersions of fatty materials
that would deposit on the fabric fibers after washing. One of the most common
ingredients used was dihydrogenated tallow dimethyl ammonium chloride (DHTDMAC),
which belongs to a class of materials known as quaternary ammonium compounds,
or quats. This kind of ingredient is useful because part of the molecule has a positive
charge that attracts and binds it to negatively charged fabric fibers. This charge
interaction also helps disperse the electrical forces that are responsible for static cling.
The other part of the molecule is fatty in nature and it provides the slip and lubricity that
makes the fabric feel soft.
While these quats do soften fabrics very effectively, they also can make them less absorbent.
This is a problem for certain laundry items such as towels and diapers.
To overcome this problem, modern formulations use quats in combination
with other more effective ingredients. These newer compounds have somewhat
lower substantivity to fabric which makes them less likely to interfere with water absorption.
One of the new classes of materials employed in fabric softener formulations
today is polydimethylsiloxane (PDMS). Siloxane is a silicone based fluid that has
the ability to lubricate fibers to give improved softening and ease of ironing.
Other silicones used in softeners include amine-functional silicones,
amide-functional silicones and silicone gums. These silicone derivatives
are modified to be more substantive to fabric and can dramatically improve its feel.
Emulsifiers
The conditioning ingredients used in fabric softeners are not typically
soluble in water because of their oily nature. Therefore, another type of
chemical, known as an emulsifier, must be added to the formula to form
a stable mixture. Without emulsifiers the softener liquid would separate
into two phases, much like an oil and vinegar salad dressing does.
There are three types of emulsifiers used in fabric softener formulations:
micro-emulsions, macro-emulsions, and emulsion polymers.
Macro-emulsions are creamy dispersions of oil and water similar to
hand lotions or hair conditioners. The emulsifier molecules surround
the hydrophobic oil or silicone droplets and allow them to be dispersed in water.
A micro-emulsion is chemically similar, but it creates oil particles that are so
small that light will pass around them. Therefore, a micro-emulsion is characterized
by its clarity and transparency as opposed to being milky white. Furthermore,
one of the advantages of micro-emulsion is that the silicone particles are so tiny
that they will actually penetrate into the fibers, while macro-emulsions only deposit
on the fiber's surface. The third type, emulsion polymers, create dispersions that
look similar to a macro-emulsion. This system does not use true emulsifiers to
suspend and dissolve the oil phase. Instead, emulsion polymers create a stabilized
web of molecules that suspend the tiny silicone droplets like fish caught in a net.
The emulsifying system used in softeners must be chosen carefully to ensure the
appropriate level of deposition on the fabric. A blend of non-ionic
emulsifiers (those that have no charge) and cationic emulsifiers
(those that have a positive charge) are typically used. Anionic surfactants
(which have a negative charge) are rarely used because the fabric conditioning
agents have a positive charge which would tend to destabilize an anionic emulsion.
Other ingredients
In addition to conditioning agents and emulsifiers, fabric softeners contain
other ingredients to improve their aesthetic appeal and to ensure the product
will be shelf stable. For example, fragrance and color are added to make the
product more pleasing to consumers. In addition, emulsion stabilizers and
preservatives are used to ensure the product quality.
The rest of the article has more info on how it's manufactured.
http://www.enotes.com/how-products-encyclopedia/fabric-softener