Antimicrobial carpet and carpet tile

A carpet and carpet tile resistant to the growth of Gram negative, Gram positive and fungal organisms which contains a polymeric non-plasticized PVC tuftlock precoat, fusion bonding adhesive, or secondary backing which has incorporated in it a phosphoric acid ester or its salt of the general formula: ##STR1## wherein R and R' are alkyl, oxyalkyl, polyoxyalkyl, aryl, aralkyl or alkaryl groups of C.sub.1 to C.sub.24, and one of R or R' can be H; X is a Group I metal ion, Group II metal ion, transition metal ion, or NY.sub.1 Y.sub.2 Y.sub.3 Y.sub.4, where Y.sub.1-4 are hydrogen, a hydrocarbon of C.sub.1 to C.sub.24, or a hydroxyalkyl group of C.sub.1 to C.sub.24 ; and there is at least one free hydroxyl group; and when X is NY.sub.1 Y.sub.2 Y.sub.3 Y.sub.4 or a Group I metal ion, n is 1, when X is a Group II metal ion, n is 2; and when X is a transition metal, n is equal to the valence of the metal.

BACKGROUND OF THE INVENTION 
This invention is in the field of carpet manufacture, and in particular 
relates to carpet and carpet tile prepared with a biocidal tuftlock 
precoat or fusion bonding adhesive. 
Bacteria, fungi, viruses, algae and other microorganisms are always present 
in our environment. Such microorganisms are frequently an essential part 
of ecological systems, industrial processes, and healthy human and animal 
bodily functions, such as digestion. In other instances, however, 
microorganisms are highly undesirable as a cause of illness, odors, and 
damage or destruction of a wide variety of materials. 
The species and numbers of microorganisms present in the environment are 
dependent on the nutrients and the moisture available for growth, as well 
as on the humidity and temperature. Nutrients for microorganisms generally 
abound in the normal environment. 
A particularly good environment for the growth of microorganisms is found 
in carpet and carpet tile. Bacteria and fungi are deposited on the carpet 
through the everyday traffic of people and animals, food and beverages 
spilled on the carpet, and animal and infant waste. Further, airborne 
microorganisms carried in from outside or carried through the heating or 
cooling system can accumulate on carpet. Soil and moisture in carpet 
provide nutrients for the growth of the microbes. Moreover, certain 
bacteria are capable of remaining viable in a dormant state on carpet for 
long periods of time until they are provided adequate sustenance. 
Organic materials used in the construction of carpet and carpet tile can be 
a source of nutrition for certain microorganisms. Carpet fibers are 
typically made from polyamides, such as nylon and wool, or from polyester, 
which are biodegradable. Tuftlock precoat or fusion bonding adhesives 
typically contain organic polymers in combination with fillers and other 
additives. Microbial digestion of these organic materials can result in 
the deterioration as well as the discoloration of the carpet over time. 
Further, the unhealthy accumulation of bacterial or fungal growth can 
create a foul odor. 
It has proved difficult, however, to develop a microbiocidal composition 
that is effective in controlling the growth of the wide variety of 
unwanted microorganisms and is, at the same time, safe for use around 
human beings and animals. Another difficulty is the extreme variability of 
response of various microorganisms to conventional microbiocidal agents. 
Even within bacteria, Gram-negative and Gram-positive bacteria respond 
differently to antibiotics. Further, antibiotics that are effective 
against procaryotic organisms are usually ineffective against eucaryotic 
microorganisms such as fungi and yeasts. 
U.S. patent application Ser. No. 047,561 entitled "Microbiocidal 
Composition and Method of Preparation" filed Apr. 27, 1987, by Robert H. 
McIntosh disclosed a broad spectrum, safe, biocidal composition having the 
following general formula: 
##STR2## 
wherein R and R' are an alkyl, aryl, aralkyl or alkaryl group, one of R or 
R' can be H, X is a Group I metal ion, Group II metal ion, transition 
metal ion, or an organic ion such as an ammonium ion, and there is at 
least one free hydroxyl group. The biocide can be effectively incorporated 
into a large variety of substrates, such as detergents, coatings, 
plastics, wood and wood products. 
U.S. Pat. No. 4,608,289 to McIntosh discloses a carpet which contains a 
dialkylalkoxyammonium dialkylphosphate in the backing coat of the carpet 
as a sanitizing agent against Gram Negative, Gram Positive and fungal 
organisms. 
Antimicrobial agents now being marketed for use in carpet fibers include 
Dow Corning.TM. 5700 Antimicrobial Agent for textile fibers and OBPA 
(10,10-oxybisphenozarsine), marketed by Morton Thiokol, Inc. Dow 
Corning.TM. 5700 Antimicrobial Agent, marketed under the tradename 
SYLGARD, is a silicone quaternary amine of the general formula [CH.sub.3 
(CH.sub.2).sub.17 N(CH.sub.3).sub.2 (CH.sub.2).sub.3 Si(OCH3).sub.3 
].sup.+ Cl.sup.-. It is applied to the carpet fiber and is activated in 
the presence of moisture. It does not kill microorganisms in the absence 
of moisture. Further, it is only active against Gram positive organisms. 
OBPA is highly toxic. 
In addition to hygenic aspects of carpet construction, consideration must 
also be given to carpet durability and manufacturing versatility. The type 
of adhesive used for the tuftlock precoat or fusion bonding adhesive is 
important to these considerations. 
The most widely used method of manufacture of fusion bonded carpet 
presently involves the use of a nonlatex PVC (polyvinyl chloride) 
plastisol formulation as the bonding adhesive. Typically, PVC plastisol is 
dispensed over a support layer to form an adhesive layer that penetrates 
into the support layer. The adhesive layer is then contacted with pile 
forming yarn. The PVC plastisol is cured, creating a product in which the 
yarn fibers are secured in the PVC layer and thereby bonded to the support 
layer. Increased strength may be obtained by bonding a secondary backing 
to the support layer. 
Alternatively, pile yarn can be woven or tufted through a primary backing. 
The yarn is then adhered to the backing with a tuftlock precoat. This type 
of carpet, in which the yarn is mechanically as well as adhesively 
attached to the backing, is generally termed "woven" or "tufted" carpet. 
PVC plastisol formulations are commonly used as the polymeric base 
material in the tuftlock adhesive precoats. 
In order to make a durable carpet in which the support layer does not peel 
away from the secondary backing, the adhesive which has permeated into the 
support layer must contact and bond with the material forming or adhering 
the secondary backing. The use of a nonlatex plasticized PVC as the yarn 
locking adhesive limits the variety of backing structures that may be 
applied to the carpet. This is true because nonlatex PVC plastisol does 
not bond strongly to common carpet backing materials such as bitumen, EVA 
(ethylene-vinylacetate), APP (atactic polypropylene), hot melts, 
urethanes, and SBR (styrene-butadiene). Furthermore, PVC plastisol is 
relatively expensive. 
A carpet and carpet tile is needed for industry and the home that is not 
only resistant to the attack and growth of microorganisms, but that can be 
made with a variety of secondary adhesives and backings compatible with 
its assorted uses. 
It is therefore an object of the present invention to provide carpet and 
carpet tile which is resistant to the growth of Gram negative bacteria, 
Gram positive bacteria, and fungi. 
It is a further object of the present invention to provide carpet and 
carpet tile which maintains its resistance to microbial growth after 
cleaning or processing. 
It is another object of the present invention to provide carpet and carpet 
tile which is rendered resistant to microbial growth without substantially 
adding to the cost of the product. 
It is a still further object of the present invention to provide a method 
to prepare antimicrobial carpet and carpet tile. 
It is yet another object of the present invention to provide a carpet and 
carpet tile which has a yarn locking adhesive which is compatible with a 
wide variety of adhesives and secondary backings. 
It is a further object of the present invention to provide a carpet which 
is durable and economical. 
SUMMARY OF THE INVENTION 
The present invention is carpet and carpet tile which is resistant to the 
attack and growth of Gram positive bacteria, Gram negative bacteria and 
fungal organisms. The carpet contains a tuftlock precoat or fusion bonding 
adhesive which has incorporated in it a phosphoric acid ester of the 
general formula: 
##STR3## 
wherein R and R' are independently alkyl, oxyalkyl, polyoxyalkyl, aryl, 
aralkyl or alkaryl groups of C.sub.1 to C.sub.24, and one of R or R' can 
be H; X is a Group I metal ion, Group II metal ion, transition metal ion, 
or NY.sub.1 Y.sub.2 Y.sub.3 Y.sub.4, where Y.sub.1-4 are hydrogen, a 
hydrocarbon of C.sub.1 to C.sub.24, or a hydroxyalkyl group of C.sub.1 to 
C.sub.24 ; and there is at least one free hydroxyl group. When X is 
NY.sub.1 Y.sub.2 Y.sub.3 Y.sub.4 or a Group I metal ion, n is 1. When X is 
a Group II metal ion, n is 2. When X is a transition metal, n is equal to 
the valence of the metal. 
The tuftlock precoat or the fusion bonding adhesive includes a non-PVC 
plastisol polymer or copolymer. A preferred embodiment is carpet and 
carpet tile product with the phosphoric acid ester in a latex adhesive. An 
especially preferred embodiment is carpet prepared with a precoat or 
adhesive of the biocidal phosphoric acid derivative in a vinyl 
acetate-ethylene copolymer. 
It has been discovered that the biocidal phosphoric acid ester diffuse from 
the primary adhesive to the upper end of the carpet fibers, providing 
protection from bacterial and fungal growth to the carpet base as well as 
throughout the fiber. The continuous migration of the phosphoric acid 
ester from the precoat or adhesive to the fiber imparts long term 
effective microbial protection to the carpet. 
In another embodiment of the present invention, the phosphoric acid 
derivative is added to the secondary backing of the carpet to provide 
protection from microbial growth between the floor and the carpet.

DETAILED DESCRIPTION OF THE INVENTION 
The present invention is carpet and carpet tile which is resistant to the 
growth of Gram negative bacteria, Gram positive bacteria, and fungal 
organisms over an extended period. The carpet represents a significant 
advancement over the prior art, in that it does not lose its antimicrobial 
effect when the carpet is cleaned or processed. The carpet or carpet tile 
includes a tuftlock precoat or a fusion bonding adhesive which contains a 
biocidal mono- or di-substituted phosphoric acid of the general formula: 
##STR4## 
wherein R and R' are independently alkyl, oxyalkyl, polyoxyalkyl, aryl, 
aralkyl or alkaryl groups of C.sub.1 to C.sub.24, and one of R or R' can 
be H; X is a Group I metal ion, Group II metal ion, transition metal ion, 
or NY.sub.1 Y.sub.2 Y.sub.3 Y.sub.4, where Y.sub.1-4 are hydrogen, a 
hydrocarbon of C.sub.1 to C.sub.24, or a hydroxyalkyl group of C.sub.1 to 
C.sub.24 ; and there is at least one free hydroxyl group. When X is 
NY.sub.1 Y.sub.2 Y.sub.3 Y.sub.4 or a Group I metal ion, n is 1. When X is 
a Group II metal ion, n is 2. When X is a transition metal, n is equal to 
the valence of the metal. 
Examples of the alkyl, oxyalkyl, polyoxyalkyl, aralkyl and alkaryl R or R' 
groups include straight chain, branched chain or cyclic alkyl groups, 
polyoxyethylene having from 1 to 12 ethylene oxide units, polyoxypropylene 
having 1 to 8 propylene oxide units, phenyl, alkylphenyl, and 
alkoxyphenyl. 
In a preferred embodiment, the biocidal phosphoric acid derivative is 
present as a trisubstituted ammonium salt. A preferred derivative is the 
di-(2-hydroxyethyl)cocoamine salt of a monoalkylphosphoric acid. The 
phosphoric acid derivative can also be a metal salt which includes, for 
example, sodium or potassium (Group IA metals), magnesium (Group IIA 
metal), or zinc (transition metal). Selection of the positive ion does 
affect biocidal activity, principally the anti-Gram negative bactericidal 
activity, although the phosphoric acid moiety appears to be the primary 
source of biocidal activity. 
The tuftlock precoat for tufted or woven carpet and the fusion bonding 
adhesive for fusion bonded carpet are collectively referred to below as 
"primary adhesives". The term carpet as used herein includes carpet and 
carpet tile. 
PREATION OF THE BIOCIDAL PHOSPHORIC ACID ESTER 
The biocidal phosphoric acid ester can be prepared by methods known to 
those skilled in the art. The majority of such methods provide a product 
mixture of mono- and di-substituted phosphoric acids which is hard to 
separate. It has been discovered that phosphoric acid esters with at least 
one free hydroxyl group are more biocidally active than phosphoric acid 
derivatives with n free hydroxyl groups. If a synthetic method is used 
which results in a mixture of mono- and di-substituted phosphoric acids, 
and the phosphoric acid mixture is reacted with a base to form a salt, the 
product mixture will contain a biocidally active salt of a monosubstituted 
phosphoric acid and a biocidally less active salt of a disubstituted 
phosphoric acid. For economy of time and expense in commercial 
manufacturing, this mixture of substituted phosphoric acid salts may be 
used without further purification in the preparation of the primary 
adhesive. 
The following example describes one method for the preparation of 
phosphoric acid esters. This example, as well as all other examples 
provided herein, are illustrative only and are not intended to limit the 
scope of the invention. 
EXAMPLE 1 
Preparation of Biocidal Phosphoric Acid Ester 
The phosphoric acid ester can be prepared by reacting 1 mole of phosphorus 
pentoxide with 3 moles of alcohol, such as 2-ethylhexanol, at a 
temperature of between about 60.degree. C. and 120.degree. C. Phosphorus 
pentoxide is slowly added to the alcohol while the mixture is agitated. 
Completion of the reaction is determined by titration of a sample of the 
resulting acid with a solution of potassium or sodium hydroxide. The 
reaction products include dialkyl phosphoric acid and monoalkyl phosphoric 
acid. 
Microbiocidal activity is tested by plating a microorganism onto Trypticase 
Soy Nutrient Agar, or other appropriate media, punching 11 mm diameter, 5 
mm deep holes into the agar, and applying 0.05 ml of each of the undiluted 
test compounds into the holes. The petri dish is examined for growth of 
the microorganism after incubation for 24 hours at 30.degree. C. The 
diameter of the clear area surrounding the hole containing the compound 
being tested is indicative of the degree of antimicrobiocidal activity. 
EXAMPLE 2 
Preparation of Ammonium Salt of Phosphoric Acid Ester 
A preferred method to form the ammonium salt of the phosphoric acid ester 
is by the neutralization of two moles of the reaction product of Example 1 
with 1.3 moles of an amine such as bis(hydroxyethyl)cocoamine, by heating 
the mixture at a temperature of between 60.degree. C. and 120.degree. C. 
until the reaction is complete. Since disubstituted phosphoric acid is a 
stronger acid than monosubstituted phosphoric acid, the disubstituted 
phosphoric acid bonds preferentially with the amine, forming (assuming 50% 
monoalkyl and 50% dialkyl phosphoric acid in the Example 1 product 
mixture) approximately 1.0 mole of the ammonium salt of the disubstituted 
phosphoric acid, 0.3 mole of the ammonium salt of the monosubstituted 
phosphoric acid, and 0.7 mole of free monosubstituted phosphoric acid. 
EXAMPLE 3 
Preparation of Metal Salts of Phosphoric Acid Ester 
Metal salts of phosphoric acid esters can be prepared by mixing a metal 
salt such as magnesium acetate or zinc acetate with the phosphoric acid 
ester, warming to dissolve, and then vacuum stripping off the acetic acid. 
Specifically, salts of 2-ethylhexylphosphoric acid were prepared by mixing 
the acid with either magnesium (Group I metal), or zinc (transition 
metal), as follows. 
______________________________________ 
1. Magnesium (acetate) 2.4 H.sub.2 O 
20 gram 
2-Ethylhexyl phosphoric acid 
53 gram 
2. Zinc (acetate) 2.2 H.sub.2 O 
15 gram 
2-Ethylhexyl phosphoric acid 
53 gram 
______________________________________ 
The metal salt was first mixed with the 2-ethylhexyl phosphoric acid, the 
solution warmed to dissolve the metal acetate, and then after dissolution, 
the acetic acid was stripped off. The resulting products were clear, 
colorless, viscous liquids. The magnesium and zinc salts of the phosphoric 
acid derivatives were washed, and then evaluated for biocidal activity 
using the following standard cup method test procedure. 
A sterile nutrient agar solution was prepared. The nutrient agar was 
inoculated with a 24 hour culture of either Staphylococcus aureus (Gram 
positive) or Pseudomonas aeruginosa (Gram negative) organism. The 
inoculated agar was poured into 100.times.15 mm sterile petri dishes and 
allowed to solidify at room temperature. After solidification, small 
reservoirs were punched for the compounds to be tested. Magnesium 
2-ethylhexylphosphoric acid was added to one well and zinc 
2-ethylhexylphosphoric acid was added to another. The plates were then 
incubated 24 hours at 30.degree. C. and examined for zones of inhibition. 
The zone of inhibition of Staphylococcus was 15 mm for the magnesium 
2-ethylhexylphosphoric acid and 19 mm for the zinc 2-ethylhexylphosphoric 
acid. No inhibition of the Pseudomonas was observed, however, the results 
clearly demonstrate that Group II and transition metal salts of the alkyl 
phosphoric acid have bactericidal activity. 
PREATION OF BIOCIDAL TUFTLOCK PRECOAT OR FUSION BONDING ADHESIVE 
The primary adhesive in the antimicrobial carpet of the present invention 
includes a polymer or copolymer other than a plasticized polyvinyl 
chloride which has suitable adhesive strength to bind the carpet fibers to 
the primary backing. A preferred embodiment is carpet and carpet tile 
product with a latex adhesive. Examples are polymers and copolymers of 
vinyl acetate-ethylene, styrene-butadiene, vinylidene chloride, vinyl 
chloride, cellulose acetate butyrate, vinyl chloride-acrylonitrile, vinyl 
acetate-acrylic acid, vinylidene chloride-acrylonitrile, acrylic 
acid-methacrylic acid, butadiene-acrylonitrile, acrylic acid-styrene, 
acrylonitrile-styrene, acrylonitrile-acrylic acid, acrylonitrile-alkyl 
acrylate, vinyl acetate acrylate ester, and acrylonitrile butadiene 
styrene. 
A preferred embodiment is carpet prepared with a vinyl acetate-ethylene 
(VAE) copolymer. A VAE primary adhesive which contains a high vinyl 
acetate content, for example greater than 50% vinyl acetate, provides 
superior fiber lock performance and wear durability. U.S. Ser. No. 
224,057, entitled "Latex Fusion Bonded Pile Carpets and Carpet Tile", 
filed July 25, 1988, by Lawrence W. Blakely and Michael A. Howe, and 
incorporated herein by reference, describes a fusion bonded carpet in 
which the pile yarn is secured in a latex adhesive base which includes a 
latex polymer such as vinyl acetate-ethylene. 
The biocidal phosphoric acid ester can be mixed with the polymeric adhesive 
in a ratio of 0.2 to 10 parts by weight of the phosphoric acid ester or 
its salt to 100 parts by weight of polymeric solids. A preferred ratio is 
2.5 to 3 parts by weight of the phosphoric acid ester to 100 parts by 
weight of polymeric solids. If more than 10 parts by weight of the 
phosphoric acid ester or its salt is used in latex compositions, the 
compound can act as a plasticizer, softening the adhesive, and decreasing 
carpet durability. 
When the phosphoric acid ester or its salt is added to commercially 
prepared solutions of latex polymeric solids, a problem of precipitation 
or insolubility sometimes occurs. It is thought that the acidic phosphoric 
acid moiety may cause premature polymerization or coagulation of the 
latex. This problem is especially acute when the pH of the latex solution 
is greater than 7.0. 
It has been discovered that this problem can be avoided by adding the 
phosphoric acid ester to the polymeric latex solution in an ammoniated 
form. For example, a solution of phosphoric acid ester or its salt, water 
and ammonia can be prepared which converts approximately all of the free 
hydroxyl groups in the phosphoric acid solution to the corresponding 
ammonium salts. This ammoniated solution is then added to the polymeric 
latex solution. 
The following is an example of a method to prepare an ammoniated solution 
of the biocidal phosphoric acid ester or its salt which is compatible with 
many commercial latex preparations. 
EXAMPLE 4 
Preparation of Ammoniated Solution of Phosphoric Acid Ester 
An ammoniated solution of the di-(2-hydroxyethyl)cocoamine salt of 
2-ethylhexylphosphoric acid is prepared by: 
i) mixing 9.24 parts by weight of water with 16.65 parts by weight of a 
28-30% solution of ammonium hydroxide; and then 
ii) slowly adding the solution from step i) to 74.10 parts by weight of the 
product of Example 3, keeping the temperature at or below 120.degree. F. 
EXAMPLE 5 
Preparation of Solution of Latex Polymer and Ammoniated Phosphoric Acid 
Ester 
The product of Example 4 can be added to a polymeric solution of latex 
solids in a range of 0.3 to 13.50 parts by weight of solution in Example 4 
(corresponding to 0.2 to 10 parts by weight of substituted phosphoric 
acid) to 100 parts by weight of polymeric solids. 
When a latex primary adhesive prepared with an ammoniated phosphoric acid 
derivative is cured during carpet manufacture, the ammonia is expelled, 
leaving the biocidal phosphoric acid ester or its salt in the cured latex. 
The biocidal tuftlock precoat or fusion bonding adhesive can be formulated 
with other compounds to increase its suitability as an adhesive and to 
impart added beneficial properties to the carpet. For example, a flame 
retardant can be added such as alumina trihydrate, which at high 
temperature generates steam instead of smoke. Other flame retardant 
compounds which can be used include inorganic carbonates, such as 
CaCO.sub.3, MgCO.sub.3, BaCO.sub.3, metal oxides, borates, sulfonates, 
phosphates, and halogenated organic compounds such as pentabromophenyl 
ether. 
A dispersing agent can be added to the formulation to insure that the flame 
retardant is sufficiently evenly distributed. An example is Narlex-LD 45 
by National Starch and Chemical Corporation. 
A defoamer can be added to increase the density of the adhesive on curing. 
An example of a defoaming agent is Foammaster VF from Henkel Corporation. 
The viscosity of the adhesive or precoat can be adjusted as necessary with 
a thickener such as Natrosol 250HR by Hercules, Inc. or Paragum 141 by 
Parachem Southern, Inc. Natrosol 250 HR is activated at a pH of greater 
than 7.0. If necessary, a base such as ammonia can be added to the 
polymeric formulation to increase the pH when Natrosol is used. 
Catalysts can be added to crosslink latex adhesives. For example, ammonium 
chloride acts as a catalyst to crosslink vinyl acetate ethylene 
copolymers. Crosslinking of a latex adhesive with the aid of compounds 
such as melamine is beneficial to prevent softening and degradation of the 
adhesive layer on exposure to water. 
In general, a fusion bonding adhesive must have stronger adhering 
properties than a tuftlock precoat, because a fusion bonding adhesive 
bonds fibers to a base layer, whereas a precoat merely secures fibers 
which are woven or tufted through a primary backing. Fusion bonding 
adhesives, therefore, must have less filler and a higher relative 
proportion of polymer than tuftlock precoats. 
Tables 1-7 below provide examples of formulations for tuftlock precoats and 
fusion bonding adhesives for antimicrobial carpet and carpet tile. The 
ingredients are expressed in parts by weight. Variations of these 
formulations can be prepared within the scope of this invention. 
EXAMPLE 6 
Antimicrobial Fusion Bonding Adhesive Prepared with a Latex Polymer 
TABLE 1 
______________________________________ 
Ingredient Parts By Weight 
______________________________________ 
Latex 180-250 
Alumina Tri-Hydrate 
50-250 
Ammonium Chloride 0-10 
Ammonia as required to raise pH 
above 7.0 if Natrosol 250 
HR is used 
Narlex-LD 45 0-3 
(Dispersing Agent for ATH) 
Defoamer 0-3 
Natrosol 250HR as required to acheive 
(Thickener) desired viscosity 
Cymel 373 (Crosslinking Agent) 
0-10 
Ammoniated Phosphoric 
0.3-13.50 
Acid Ester or its Salt 
______________________________________ 
EXAMPLE 7 
Antimicrobial Fusion Bonding Adhesive Prepared with a Vinyl Acetate 
Ethylene Copolymer 
TABLE 2 
______________________________________ 
Ingredient Parts By Weight 
______________________________________ 
VAE Latex 192 
Aluminum Tri-Hydrate 
100 
Ammonium Chloride 
3.9 
DeFoamer 0.1 
Ammonia as needed to give pH 
of 7.5 
Natrosol 250 HR as needed to achieve 
desired viscosity 
Ammoniated Phosphoric 
0.3-13.50 
Acid Ester or its Salt 
______________________________________ 
EXAMPLE 8 
Antimicrobial Fusion Bonding Adhesive Prepared with a Styrene Butadiene 
Polymer 
TABLE 3 
______________________________________ 
Ingredient Parts By Weight 
______________________________________ 
SBR latex 200 
Alumina Trihydrate 100 
defoamer 0.1 
dispersant 0.1 
Paragum 141 as needed to acheive 
desired viscosity 
Ammoniated Phosphoric Acid 
0.3-13.50 
Ester or its Salt 
______________________________________ 
EXAMPLE 9 
Antimicrobial Fusion Bonding Adhesive Prepared with a Vinyl Acetate 
Acrylate Ester Copolymer 
TABLE 4 
______________________________________ 
Ingredient Parts By Weight 
______________________________________ 
Vinyl acetate acrylate ester 
217 
Alumina Trihydrate 
100 
defoamer 0.1 
dispersant 0.1 
Paragum 141 as needed to achieve 
desired viscosity 
Ammoniated Phosphoric 
0.3-13.50 
Acid Ester or its Salt 
______________________________________ 
EXAMPLE 10 
Antimicrobial Tuftlock Precoat Prepared with a Vinyl Acetate Ethylene 
Copolymer 
TABLE 5 
______________________________________ 
Ingredient Parts By Weight 
______________________________________ 
VAE Latex 192 
Alumina Trihydrate 
150 
Ammonia as required to raise pH 
above 7.0 if Natrosol 250 
HR is used 
Narlex-LD 45 0-3 
(Dispersing Agent for ATH) 
Defoamer 0-3 
Natrosol 250HR as required to achieve 
(Thickener) required viscosity 
Cymel 373 0-10 
Ammoniated Phosphoric 
0.3-13.50 
Acid Ester or its Salt 
______________________________________ 
EXAMPLE 11 
Antimicrobial Tuftlock Precoat Prepared with a Styrene Butadiene Polymer 
TABLE 6 
______________________________________ 
Ingredient Parts By Weight 
______________________________________ 
SBR latex 200 
Alumina Trihydrate 
150 
defoamer 0.1 
dispersant 0.1 
Paragum 141 as needed to achieve 
desired viscosity 
Ammoniated Phosphoric 
0.3-13.50 
Acid Ester or its Salt 
______________________________________ 
EXAMPLE 12 
Antimicrobial Tuftlock Precoat Prepared with a Vinyl Acetate Acrylate Ester 
Copolymer 
TABLE 7 
______________________________________ 
Ingredient Parts By Weight 
______________________________________ 
Vinyl acetate acrylate ester 
217 
Alumina Trihydrate 
150 
defoamer 0.1 
dispersant 0.1 
Paragum 141 as needed to achieve 
desired viscosity 
Ammoniated Phosphoric 
0.3-13.50 
Acid Ester or its Salt 
______________________________________ 
BIOCIDAL EFFECT OF ANTIMICROBIAL CARPET AND CARPET TILE 
Carpet and carpet tile prepared according to the present invention is 
protected from microbial growth both at the primary backing and on the 
fibers, because the phosphoric acid ester migrates from the adhesive up 
the fibers over time. Further, the continuous migration of the phosphoric 
acid ester serves to replenish to biocide to the fibers, providing long 
term effectiveness. 
Fusion bonded and tufted carpet prepared with biocidal vinyl acetate 
ethylene primary adhesives were tested for their ability to inhibit the 
growth of a Gram positive organism (S. aureus), a Gram negative organism 
(P. aeruginosa), and a fungal organism (A. niger). 
The following procedure was used for both fusion bonded and tufted carpet. 
An 18 hour nutrient broth culture of S. aureus was adjusted with sterile 
nutrient broth to an absorbency of 0.044 at 600 nm, representing a 
concentration of approximately 10.sup.9 cells/mL. An 18 hour nutrient 
broth culture of P. aeruginosa was adjusted with sterile nutrient broth to 
an absorbency of 0.042 at 600 nm, also representing a concentration of 
approximately 10.sup.9 cells/mL. 
One 200 mL aliquot of nutrient agar was inoculated with 2 mL of 10.sup.6 
cells/mL nutrient broth of S. aureus, and a second 200 mL aliquot of 
nutrient agar was inoculated with 2 mL of 10.sup.6 nutrient broth of P. 
aeruginosa, to yield final concentrations of 10.sup.4 cells per mL in each 
solution. Potato dextrose agar was inoculated with 2 mL of A. niger in a 
saline suspension. The inoculated agars were swirled until mixed. 
Test and control carpet samples were cut into 1".times.11/2" pieces. Half 
of each piece was shaved to the backing/base layer. Each sample was placed 
in a separate 100.times.15 mm sterile petri dish. 
Sufficient inoculated agar was poured onto the carpet samples in the 
sterile petri dishes to cover the shaved base layer of the carpet. Sterile 
agar was used to cover the control sample. Sterile tongs were used to 
manipulate the carpet pieces in order to force the air out of the pieces 
and to insure that each piece was completely saturated. The dishes were 
then covered and the agar left to solidify at room temperature. 
The dishes were placed in a 20.degree. C. incubator for approximately 48 
hours. The samples were then visually inspected for zones of inhibition 
against Gram-positive and fungal organisms at the backing and fiber 
layers. A stereomicroscope was used to evaluate surface inhibition of 
Gram-negative bacteria. 
EXAMPLE 13 
Inhibition of Microbial Growth on Fusion Bonded Carpet Tile Prepared With a 
VAE Adhesive 
Fusion bonded I-tuft carpet tile was prepared with nylon fibers adhered to 
a fiberglass primary backing with a vinyl acetate ethylene biocidal 
adhesive prepared as in Example 7, with 3.5 parts by weight of ammoniated 
phosphoric acid ester as prepared in Example 4. A secondary backing of 
plasticized polyvinyl chloride was applied. 
During the course of manufacture, the top layer of I-tufted carpet fusion 
bonded carpet is given two heat treatments while the bottom layer is given 
one heat treatment. In order to test the effect of additional cure on the 
biocidal effect of the carpet, the carpet samples were labeled "top" or 
"bottom", on the basis of whether they exited the carpet tile production 
line as the top or bottom layer of the I-tuft precursor carpet. 
The results of Experiment One and Two are presented in Tables 8-9. Both 
"top" and "bottom" carpet samples exhibited good zones of inhibition 
against Gram positive and fungal organisms, and either a zone of 
inhibition or good surface inhibition against Gram negative organisms. 
TABLE 8 
______________________________________ 
Experiment One 
S. P. aeru- 
Tile Run aureus ginosa A. niger 
Position B F B F B F 
______________________________________ 
Top - - - - - - 
Bottom - -* - - - .+-. 
(5 colonies) 
Top - -* - - - .+-. 
(1 colony) 
Bottom - - - - .+-. 
.+-. 
Control + + + + + + 
______________________________________ 
+ "Growth" -- no bacterial inhibition. 
- No growth -- good bacterial inhibition. 
.+-. Spotty inhibition with some colonies on carpet. 
*These samples produced larger zones of inhibition against the 
Grampositive bacteria. 
TABLE 9 
______________________________________ 
Experiment Two 
S. P. aeru- 
Tile Run aureus ginosa A. niger 
Position B F B F B F 
______________________________________ 
Top - - + + - - 
Bottom - - SI SI - - 
Top - - SI SI - - 
Bottom - - SI SI - - 
Control + + + + + + 
______________________________________ 
EXAMPLE 14 
Inhibition of Microbial Growth on Tufted Carpet Tile Prepared With a VAE 
Adhesive 
Tufted carpet tile was prepared with nylon fibers tufted into a woven 
polypropylene primary backing and adhered with a vinyl acetate ethylene 
biocidal precoat prepared as in Example 10, with 0.5-3 parts per weight of 
VAE polymer solids of ammoniated phosphoric acid ester as prepared in 
Example 4. 
In Experiment Three, one tufted sample was tested without a secondary 
backing, and a second sample was tested with a thick polyvinyl chloride 
plastisol secondary backing as used in carpet tile. The results of 
Experiment Three are presented in Table 10. Both the unbacked and the PVC 
backed carpet tile exhibited good zones of inhibition against Gram 
positive and fungal organisms. There was good surface inhibition of the 
Gram negative organism at the primary backing. 
TABLE 10 
______________________________________ 
Experiment Three 
S. P. aeru- 
Tufted aureus ginosa A. niger 
Carpet Sample B F B F B F 
______________________________________ 
No secondary backing 
- - SI + - - 
PVC Plastisol - - SI + - - 
secondary backing 
Control + + + + + + 
______________________________________ 
Key: 
+ "Growth" -- No inhibition 
- "No Growth" -- Good inhibition 
SI Good surface inhibition (fewer colonies, but not zone of inhibition) 
In Experiment Four, Quantum Plus II and Basics Plus carpet products, which 
are tufted loop pile nylon carpet tiles with VAE primary backings and 
plasticized PVC secondary backings, were tested for inhibition of Gram 
positive, Gram negative and fungal organisms. The results are presented in 
Table 11. 
TABLE 11 
______________________________________ 
Experiment Four 
Carpet Sample 
Description S. aureus P. aeruginosa 
A. niger 
______________________________________ 
3 Quantum Plus II 
- SI - 
Samples - SI - 
- SI - 
1 Basics Plus - SI - 
Sample 
______________________________________ 
As shown, all four samples exhibited a zone of inhibition against Gram 
positive and fungal organisms and good surface inhibition of Gram negative 
organisms. 
In Experiment Five, two samples of tufted carpet with a vinyl acetate 
ethylene precoat, nylon fibers, and a plasticized polyvinyl chloride 
secondary backing were tested for their biocidal properties against Gram 
positive and Gram negative organisms, with AATCC Antibacterial Test 
Methods 100 and 147. Sample 1 had 1.1% of ammoniated 
di-(2-hydroxyethyl)cocoamine salt of 2-ethylhexylphosphoric acid in the 
precoat, and sample 2 had 1.5% of the same compound in the precoat. The 
results are provided in Tables 12 and 13. The results of both AATCC tests 
147 and 100 indicate good performance of the carpet tile against Gram 
positive and Gram negative organisms. 
TABLE 12 
______________________________________ 
AATCC Method 100 
S. aureus P. aeruginosa 
1 100% Reduction 100% Reduction 
2 100% Reduction 99.9% Reduction 
AATCC Method 100 
S. aureus P. aeruginosa 
1 100% Reduction 99.9% Reduction 
2 86% Reduction 97.1% Reduction 
______________________________________ 
TABLE 13 
______________________________________ 
AATCC Method 147 (Shaved Backing in Contact with Acar) 
S. aureus 
K. pneumonia 
______________________________________ 
Control 0 mm 0 mm 
1 3-5 mm 1-3 mm 
2 3-5 mm 1-3 mm 
______________________________________ 
CARPET TILE WITH BIOCIDAL SECONDARY BACKING 
Microorganisms can accumulate not only in carpet fibers and at the primary 
backing, but also between the floor and the secondary backing of carpet or 
carpet tile, causing a foul odor and creating an unsanitary condition. 
In an additional embodiment of the present invention, a biocidally 
effective amount of the phosphoric acid ester is added to the secondary 
backing of carpet to impart resistance to microbiocidal growth between the 
carpet and the floor. 
The phosphoric acid ester or its salt is added to the secondary backing in 
a range of 0.2-10 parts per 100 parts by weight of base material solids. 
If the base material is a water based system, and especially one with a pH 
of greater than 7.0, the phosphoric acid ester should be added in an 
ammoniated form. Any base material suitable as a secondary backing can be 
used, for example polyvinyl chloride, ethylene vinyl acetate, 
polycarbonate, styrene butadiene rubber, ethylene propylene 
dicyclopentadiene (EPDM or EPTR), neoprene (poly(1,4-chloroprene)), 
acrylonitrile copolymers, bitumen or urethane. Fillers and additives used 
in the art, including those described for use in the biocidal primary 
adhesive, can be added to the secondary backing along with the phosphoric 
acid ester. Table 14 provides an example of an antimicrobial secondary 
backing composition. 
TABLE 14 
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PVC Resin 100 parts 
Plasticizer 30-70 parts 
(Dioctylphthalate) 
CaCO.sub.3 filler 0-250 parts 
Heat Stabilizer 0-0.5 parts 
Phosphoric Acid Ester 0.2-10 parts 
or its salt 
______________________________________ 
Modifications and variations of the present invention, antimicrobial carpet 
and carpet tile and to method of preparing it, will be obvious to those 
skilled in the art from the foregoing description. Such modifications and 
variations are intended to come within the scope of the appended claims.