Diapers designed using wood pulp without the technology of Super Absorbent cores become sodden with urine and stool enzymes causing bulkly swollen diapers which create a friction rash on baby's skin...the most common cause of baby rash.
Diapers that utilize a Super Absorbent Core rapidly absorbe Urine and stool enzymes safely locking these harmful by-products away inside the Super absorbent core. When urine is locked away inside the core of your baby's diapers it is rendered harmless, saving your baby's skin from exposure to these rash and infectous fluids reducing infection of baby's skin and bladder (urinary tract infection).

Read more about Super absorbent Core press Science behind baby's diapers

Two most common causes for rash

Friction rash from Bulky Diapers. This is the most common form of diaper rash, and affects almost all babies at some time. It is most common on areas where friction is most pronounced, such as the inner thighs, bulky cotton & wood pulp stuffed diapers, or under the elastic of diapers that are too tight. It comes and goes quickly, and responds well to frequent diaper changes, airing out, protective barriers and using slimmer diapers by diapersite.com Ultra Baby Diapers.

Irritant rash. This is most conspicuous on the exposed areas, such as the round part of the buttocks. It tends to spare skin folds and creases. It's generally the result of contact with stool enzymes or irritants such as harsh soaps, baby wipes, detergents, or topical medicines.
More about baby skin rash press here: What Causes Skin Rash
Read what the FDA has to say about using Sodium Polyacrolates (Super absorbent core) in your baby's diapers, press here: FDA Study Salt base Polymers