THE EVOLUTION OF FLOOR FINISHES

In order to understand the importance of floor finish­es, one should know a little about their history and the changes that lead to the modern technology behind the floor finishes used today.  The first finishes were Carnauba waxes.  Carnauba is a natural wax emulsion blend combined with a resin. Car­nauba waxes were extremely buff-able.  They dried to a slight haze and left deep, rich swirls on the floor when buffed.  They were extremely abrasive-resistant.

Natural waxes have been used as a floor finish since the days of the Romans and the Egyptians. Even though, carnauba and other natural waxes reached their height of popularity in the U.S. in the 1920's and 1930's.

Synthetic wax/polymer finishes followed carnauba wax.  Synthetic waxes are blended with polymers, resins and plasticizers.  The improved result was a dry, bright finish.  The buff-ability of the finish depended on the type of synthetic wax and polymers that were put into them.  Synthetic wax/polymer finishes in liquid form are a milky white color.  Synthetic waxes were being used in conjunction with carnauba wax in the 1940's and 1950's.  But, in the 1950's, floor finish technology took a leap forward when acrylic polymers were used to make floor polishes.

Acrylic polymers or water-clear finishes brought with them the promise of instant shine without buffing. But, just like "no-wax" floors, they still weren't labor-free.  They looked like a gallon of water, but they did not hold up as well in the industrial and institutional fields. 

In the 1960's, the next major breakthrough occurred with the development of metal or zinc cross-linked acrylic polymer finishes.  These products were extremely deter­gent-resistant and could be scrubbed with normal clean­ers without having to worry about removal.  But they were hard and brittle and tended to powder when bur­nished with the new high-speed equipment introduced in the 1970's.

As polymer chemistry significantly improved, the next major step in floor finishes was the introduction of high-speed equipment. Initially, floor machine buffing was done at 175 rpm's. Then came 350-500 rpm's.  Now machines are available with 1000,1200,1500, 2000 and 2500 rpm's.  Due to the heat and abrasion generated by these high-speed machines, the older, metal crosslink finishes would fracture, shatter and powder off the floor.  As a result of high-speed machines, Polythermic floor finishes were introduced to withstand the heat and abrasion generated. The high-speed burnishers abrade the floor finish and smooth it into a "wet look" during the curing process.  Polythermic finishes rely on a new generation of poly­mers that don't powder because they form a film on the floor surface that has a high degree of flexibility.  Origi­nally, manufacturers were trying to develop finishes that were harder, so that they would stand up to the heat and friction of the higher speeds, but it was found that the real key was flexibility.

Another term used in conjunction with Polythermic finishes is thermoplastic.  A thermoplastic material is simply one that will become pliable, or "plastic," when it is heated.  All finish films on the market will soften with heat, and are therefore thermoplastic.  Of course, thermoplastic materials can differ in a lot of ways, in­cluding their toughness or hardness, and in the temper­ature at which they will soften, but high speed burnish­ing does not change the softening or thermoplastic characteristic of the film.

High Speed Floor Finish Chemistry – A modern high-speed floor finish is composed of three major ingredients and a number of less significant, al­though still important additives. The three major in­gredients are polymer,  "wax," and solvents called "coalescents" or plasticizers.

Polymers - The polymer, which is a relatively large chemical en­tity of the finish, is by far the major constituent of the finish formulation. The polymer is the main building block responsible for forming the floor polish film.  Consequently, the inherent properties of the polymer deter­mine to a large degree the performance of the floor fin­ish itself. The polymer will determine the ultimate finish gloss, hardness, toughness, scuff resistance, mark resistance, scratch resistance, soil resistance, water re­sistance, detergent resistance, removability, powder re­sistance and slip resistance. These film properties can be modified to some extent by the other ingredients in the finish formulation, but the maximum performance in each of these areas is determined by the polymer.

Wax - The second major component of high speed finishes, wax, is also a synthetic polymer, although of entirely different composition.  The name "wax," which is com­monly used to describe this material, has been held over from old technology.  Most formulations now contain polymeric substitutes with "waxy" characteristics.  This characteristic is the primary difference between tough polymeric binder and the much softer synthetic "wax."  The primary function of "wax" in the formulation is to provide a level of lubricity to the finish film.  This lubricity translates into buff-ability, as it used to be practiced with low speed machines and brushes. The higher the amount of the waxy ingredient in the formulation, the more buff-able is the finish.  On the other hand, wax makes the film softer and hence makes the floor polish film much more sus­ceptible to scuffing and dirt pickup.

Solvents - The third formulation component of high-speed finishes is actually a combination of a number of liquid ingre­dients to facilitate formation of a film during the dry­ing process.  In a sense, these materials could be regarded as solvents for the polymer.  There are two basic classes of these solvents, Coalescents and Plasticizers.  Coalescents are solvents that evaporate shortly after the film is formed on the floor.  Plasticizers, on the other hand, are much less volatile and stay in the film much longer.  In fact, many stay during most of the life of the finish on the floor.  Both ingredients soften the polish film, but for a dif­ferent period of time. A highly volatile coalescent will evaporate relatively quickly and leave the film hard, while a Plasticizer will stay in the film and keep the film soft.  The primary function of the other ingredients in the formulation of high-speed finishes is to promote applica­tion or wetting and leveling properties of the finish on the floor.

For more information on floor finishes, read IHM's guide to Choosing The Right Floor Finish