The Bottom Line: Floor Squeegees and Linatex
1. Executive Summary
This document explains the importance of floor squeegees on floor scrubbing machines,
compares the materials used in making them, describes their characteristics, and shows
the relationship between material properties and total cost of ownership.
2. Introduction
Commercial and industrial floor scrubbers range from compact, battery-powered models
to full-sized, ride-on machines. Made and used around the world, they all operate on
similar principles. Each applies a surfactant and medium, usually detergent and water, to
the floor. It uses brushes or abrasive pads to loosen dirt and debris while skirts contain
the solution to the working width of the machine, then removes the suspended soils and
liquids with a vacuum. The last and most critical part in this system is the squeegee; it
determines how much is removed from the floor—and how much is left behind.
3. Purpose and Scope
To make informed choices, buyers must have basic knowledge about the product class.
Useful information about floor squeegees, however, is hard to find. An online search for
comparison of squeegee materials yields only price lists. A leading maker of manual
squeegees guards its formulation “with the same secrecy and security afforded soft drink
formulas.” And even though the international cleaning industry association website
www.issa.com offers scores of articles on floor care, not one of them focuses on the
selection, use, or care of squeegees.
This document is an attempt to provide accurate descriptions and comparisons of floor
squeegee materials, supported by industry experience and documented testing.
4. Approach
Midwest Rubber Service & Supply Company globally manufactures, fabricates, and
distributes high quality rubber products—including floor squeegee blades and skirts. The
company offers original and replacement parts, product development support, and
material testing for leading manufacturers of floor cleaning machines.
The Midwest Rubber testing facility near Shanghai helps researchers measure and
compare physical characteristics under controlled conditions for accurate and relevant
results. For this document, researchers evaluated multiple properties, such as resilience,
modulus, deflection, tear resistance, and wet abrasion, then related those properties to
performance in floor squeegees.
Disclaimer: As the patent holder for PRIMOthane®, an oil and chemical resistant
polyurethane, and as the exclusive global distributor for floor care squeegees made from
Linatex®, Midwest Rubber clearly has a commercial interest in the sale of those
products. And because Linatex and PRIMOthane are specifically made to provide
effective floor cleaning results, they do well in side-by-side comparisons with generic
commodity rubber products. This document reflects test results that assess each material
equally.
5. Discussion
Clean floors help make public and private shared spaces brighter, safer, and more
appealing. Cleaner floors improve occupant satisfaction, employee morale, guest safety,
and risk management. This creates a large global market for floor scrubbing machines.
With flexible power sources, innovative surfactants, and ergonomic controls, these
complex and capable machines clean large areas quickly. Every night, they scrub
countless square kilometers of retail stores, schools, hospitals, offices, airports, and other
buildings with heavy foot traffic. By keeping floors free of visible grime and unseen slipand-fall hazards, they help promote an image and fact of cleanliness and safety.
Manufacturers base their marketing claims on effectiveness and efficiency, emphasizing
proprietary features that set machines and makers apart from those of competitors. Yet all
the technology that loosens dirt and debris has little value if the squeegee fails to pick
everything up. A poorly made, incorrectly chosen, or badly worn squeegee can cancel out
the most successful scrubbing job. A squeegee blade that fails to seal against the floor
surface will leave behind water, soap, soils, oils, and more.
Safety and Health
Clean floors help create pleasant indoor environments. People are happier and more
productive when their facilities are clean. They are also safer and healthier:
“The services, wholesales and retail trade industries together accounted for the greatest
proportion of injuries (over 60%) that resulted from same level falls (over 60%), while
the manufacturing sector alone accounted for 16% of injuries that resulted from same
level falls.”—OSHA / ISSA Alliance Website: 2007 Liberty Mutual Workplace Safety
Index
“One of the greatest workers compensation and liability exposures confronting many
companies across the country is slip and fall incidents. A fall can result in the loss of a
valued employee or the filing of a third-party lawsuit. Many of these incidents can be
prevented.”—Loss Prevention Bulletin, Zurich North America
According to the National Floor Safety Institute, slip-and-fall accidents cost billions of
dollars each year in medical expenses, insurance payments and lost productivity.
“Surfaces are only considered hygienically clean when they have been wiped with a
cloth. Microorganisms can only be removed by being wiped away. This principle also
applies for the cleaning of floor coverings. Through correct cleaning alone, germs can be
reduced by up to 80 percent.”—European Cleaning Journal
Natural and Synthetic Rubber
Rubber can be made from natural or synthetic raw materials. The most common types are
natural latex, harvested from the rubber tree Hevea braziliensis, and man-made chemical
polyisoprene, most often created from butadiene and styrene gases. These are blended
with other ingredients to create a specified set of characteristics, then extruded, pressed,
or molded in sheets, bars, and other shapes.
Rubber and polyurethane are thermoset products, with chemical bonds that cannot be
reversed. Once the material is heated and formed, it will not change shape again. Even if
it is heated to a melting point, it will not have the same properties after it cools. For
common industry terms about rubber, please refer to ASTM Standard D1566.
Physical Properties
A. Resilience
In rubber, resilience can be defined as the ratio of return to impressed energy. In practical
terms, resiliency allows rubber to absorb impact from hard objects, then return the energy
to the object and regain its original shape. By contrast, rigid materials do not deform; the
same kinetic energy that is absorbed by a resilient material would create friction and
noise in a rigid one. This property makes rubber a preferable choice of material in many
abrasive environments. See Figure 1 below.
Figure 1. Resilience
B. Modulus
How easily a material can be deformed by weight or mechanical force is its measure of
modulus. The higher the modulus, the more energy is needed to create deflection—a term
that describes the relationship of a squeegee blade to a floor surface.
A modulus that is too high will result in excessive deflection, which creates noise,
vibration, and streaks of water where the rubber did not seal to the floor. Lower-modulus
materials require less downforce to create an effective seal with the floor, which reduces
machine effort and reduces squeegee blade wear.
This critical factor in performance is difficult or impossible to judge without test
equipment. As Figure 2 below shows, a comparison of eight squeegee materials revealed
significant differences. All the materials looked and felt about the same, but their
modulus characteristics varied significantly.
Figure 2. Modulus
C. Tear Resistance
The purpose of a floor squeegee is to create a seal with the floor surface, so that the
vacuum system can recover water and suspended soil from the floor. Any tearing will
break that seal and keep the squeegee from doing an effective job. As Figure 3 below
shows, this property does not correspond directly to modulus. Some materials are
relatively easy to deform but resist tearing.
Figure 3. Tear Resistance
D. Wet Abrasion
Not all rubber has the same characteristics; each type of rubber wears at a different rate,
and responds differently under dry and wet use. Rubber used in a floor squeegee endures
wear from both abrasion and wet conditions. As with a squeegee that has incorrect
deflection or tearing, one with excessive wear requires immediate adjustment and
eventual replacement. This means diminished machine performance, and higher costs for
both labor and materials. Figure 4 below shows the wear resistance of several materials.
Figure 4. Wet Abrasion
About Linatex
A. Brief History
The Linatex product, brand, and company were established in the 1920s. In Processing of
Natural Rubber, John Cecil and Peter Mitchell describe how the venture began:
In 1923, Bernard Wilkinson discovered a way to ‘cold-vulcanize’ rubber
in the liquid phase by adding vulcanizing chemicals to field latex. His
objective was to retain as much as possible of the original quality of the
latex, by minimizing the extent to which the polymer was damaged by
mechanical shear. As this was the first time that vulcanizing chemicals
had been added to field latex, he was able to obtain a patent.
B. Formulation
By vulcanizing field latex, Wilkinson was able to maintain higher integrity in the long
molecular chains of the natural polymer, resulting in a higher molecular weight. As latex
is subjected to mechanical shearing in handling and manufacturing, molecular chains are
disrupted, molecular weight declines, and important physical properties are diminished.
Figure 5 below shows how closely Linatex matches the original qualities of latex.
Figure 5. Molecular Weight Distribution
C. Applications
Its resistance to abrasion, impact, and corrosion has made Linatex a popular choice for
protective lining in pumps, valves, chutes, and containers. It was used to line the fuel
tanks of Spitfire fighter planes in World War II, re-sealing bullet holes and reducing the
risk of fire. According to Weir Minerals, which holds the global patent on Linatex, about
75 percent of the product made today is used in the mining industry.
While other materials have some of the desired properties for use in floor squeegees,
Linatex meets more of those criteria than any other rubber. Its characteristics are difficult
to reproduce with other materials. As a specialist at Linatex put it, “There are a number of
materials in the market that match some aspects but none that match all of them.”
Linatex v. Linatex
The name Linatex refers to the company, a part of Weir Minerals, and to more than one
grade of its products. The material used in mining applications is very similar to the one
used in floor squeegees. In testing, however, we found significant differences. Floor
care–grade Linatex is made to tighter tolerances for thickness, features a smooth finish on
both sides, and delivers measurably better performance when used in floor squeegees.
Using mining-grade Linatex for squeegees is both ineffective and cost-prohibitive.
D. Economic Concerns
Linatex contains 95 percent natural latex, so its cost reflects the market price for rubber.
For decades until 2005, the commodity price for rubber remained below US$1 per pound;
by the middle of 2011, the price reached nearly US$3. This has made Linatex more
expensive to produce.
In economic terms, the market for Linatex is inelastic, while the market for squeegee
rubber as a product class is highly elastic. Customers who see Linatex as a unique
material with valuable characteristics have been willing to pay more for it. Those who
view rubber as a generic commodity are more likely to use competing products.
E. Price, Cost, and Value
Floor squeegees made with inexpensive rubber have less natural latex than Linatex,
which means they have fewer of the physical properties that provide higher performance
in use. They contain fillers, from carbon black to silica to clay to chalk, that increase
hardness and tensile strength but reduce flexibility.
Floor squeegees made with lower-quality rubber are sold at lower prices than those made
from Linatex. They also deliver lower performance, require more frequent adjustment,
and wear out much sooner. Despite its higher initial price, the total cost of ownership
over time makes Linatex a more economical choice for many customers.
Environmental Advantages
According to the International Rubber Research and Development Board, a natural
rubber plantation can sequester up to 30 tonnes of CO2 per hectare per year—and natural
rubber is a renewal resource with infinite potential.
F. Competing Products
Between patent protection and material costs, no other manufacturer can make quite the
same thing as Linatex. Because they can match hardness and color, though, some make
look-alike products. But the pigment of a rubber has no bearing on its function, and
hardness is only one measure of likely performance.
Hardness is easy to check, and color is always apparent; these two factors are enough to
satisfy some customers that they are buying an equivalent product to Linatex. The less
customers know, the more effective this practice becomes. Unprincipled distributors even
sell generic rubber under the Linatex name. The simplest way to tell whether a floor
squeegee is made of Linatex is to identify the source. Midwest Rubber Service and
Supply is the exclusive distributor of floor care–grade Linatex worldwide.
Another method is less conclusive but more entertaining. Cut one or more slits in the
edge of a floor squeegee and try to tear it the rest of the way. Generic red rubber is
relatively easy to tear, while only the strongest and most determined people can get
through a piece of Linatex. Figure 6 below shows results from a recent trade event. Two
generic products appear in the left and center; the bin containing Linatex is on the right.
Figure 6. Tear Resistance Comparison
6. Conclusion
A floor squeegee represents a small fraction of the cost in any floor scrubber. It even
costs less than other consumables, such as soap or brush heads. But it makes all the
difference in how a floor looks and feels after the machine is put away. The machine’s
performance ultimately depends on the squeegee, just as a racing car depends on its tires.
For physical characteristics, performance, and total cost of ownership, floor care–grade
Linatex provides the greatest value available in floor squeegees. 