U.S. patent application number 14/678183 was filed with the patent office on 2016-10-06 for scratch resistant coating composition with a combination of hard particles.
The applicant listed for this patent is ARMSTRONG WORLD INDUSTRIES, INC.. Invention is credited to JEFFREY S. ROSS, DONG TIAN.
Application Number | 20160289979 14/678183 |
Document ID | / |
Family ID | 55861146 |
Filed Date | 2016-10-06 |
United States Patent
Application |
20160289979 |
Kind Code |
A1 |
TIAN; DONG ; et al. |
October 6, 2016 |
SCRATCH RESISTANT COATING COMPOSITION WITH A COMBINATION OF HARD
PARTICLES
Abstract
An abrasion resistant flooring covering formed from a UV curable
coating composition having binder and diamond particles--the
abrasion resistant flooring covering used to overcoat the surface
of flooring products or various abrasion heavy surfaces to protect
such a products or surfaces from damage by abrasion or scratch.
Inventors: |
TIAN; DONG; (Lancaster,
PA) ; ROSS; JEFFREY S.; (Lancaster, PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ARMSTRONG WORLD INDUSTRIES, INC. |
Lancaster |
PA |
US |
|
|
Family ID: |
55861146 |
Appl. No.: |
14/678183 |
Filed: |
April 3, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08K 2003/2227 20130101;
C09D 7/69 20180101; C08K 2201/005 20130101; C08K 3/04 20130101;
E04B 1/66 20130101; E04F 15/107 20130101; C09D 7/61 20180101; C08K
3/34 20130101 |
International
Class: |
E04F 15/10 20060101
E04F015/10; E04B 1/66 20060101 E04B001/66 |
Claims
1. A floor covering comprising a substrate, and a coating layer
comprising: a coating matrix formed from a curable coating
composition comprising a binder, wherein the coating matrix has an
average coating matrix thickness; and an abrasion resistant
particle comprising: a mixture of first abrasion resistant
particles and second abrasion particles, the first abrasion
resistant particles having an average primary particle size and a
narrow distribution of primary particle sizes, the narrow
distribution of primary particle sizes having a standard deviation
less than 35% of the primary average particle size; and wherein the
first abrasion resistant particles are diamond particle and the
second abrasion resistant particles are particles other than
diamond particles and have a Mohs hardness value of at least 6 and
the second abrasion resistant particles are present relative to the
first abrasion resistant particles in a weight ratio ranging from
1:1 to 8:1.
2. The floor covering of claim 1 wherein the coating layer
comprises less than 12 wt. % of abrasion resistant particles based
on the weight of the coating layer.
3. The floor covering of claim 2 wherein the coating layer
comprises at least 6 wt. % of the abrasion resistant particles
based on the weight of the coating layer.
4. The floor covering of claim 1 wherein the average coating matrix
thickness ranges from about 4 .mu.m to about 40 .mu.m.
5. The floor covering of claim 4 wherein the average coating matrix
thickness ranges from about 6 .mu.m to about 20 .mu.m.
5. The floor covering of claim 1 wherein the second abrasion
resistant particles are aluminum oxide and the weight ratio ranges
from about 1:1 to about 4:1.
6. The floor covering of claim 5 wherein the abrasion resistant
particles are present in the coating layer by an amount ranging
from about 6 wt. % to about 10 wt. %.
7. The floor covering of claim 1 wherein the average coating matrix
thickness is measured from a top surface of the coating matrix to a
bottom surface of the coating matrix and the abrasion resistant
particles protrude from the top surface of the coating matrix at a
distance ranging from about 1% to about 50% of the coating matrix
thickness.
8. The floor covering of claim 1 wherein the average coating matrix
thickness is measured from a top surface of the coating matrix to a
bottom surface of the coating matrix and the abrasion resistant
particles are submerged beneath the top surface of the coating
matrix at a distance that is about 1% to about 50% of the coating
matrix thickness.
9. The floor covering of claim 1 wherein the average coating matrix
thickness is measured from a top surface of the coating matrix to a
bottom surface of the coating matrix and the abrasion resistant
particles are submerged beneath the top surface of the coating
matrix at a first distance that is about 1% to about 25% of the
coating matrix thickness and the abrasion resistant particles are
vertically offset from the bottom surface of the coating matrix by
a second distance that is about 1% to about 25% of the coating
matrix thickness.
10. The floor covering of claim 1 wherein the coating matrix
thickness to the first particle size form a ratio ranges from 0.6:1
to 2:1.
11. A floor covering comprising a substrate, and a coating layer
comprising a coating matrix formed from a curable coating
composition comprising a binder, the coating matrix comprising an
average coating matrix thickness: and abrasion resistant particles
comprising: first abrasion resistant particles having an average
particle size ranging from 2 .mu.m to 50 .mu.m, and second abrasion
resistant particles that have a Mohs hardness value of at least 6;
wherein the first abrasion resistant particles are diamond
particles and the second abrasion resistant particles are particles
other than diamond, and wherein an average distance between two
adjacently placed first abrasion resistant particles ranges of from
20 .mu.m to 75 .mu.m.
12. The floor covering of claim 11 wherein the coating layer
comprises 6 wt. % to 12 wt. % of abrasion resistant particles based
on the weight of the coating layer.
13. The floor covering of claim 11 wherein the a ratio of the
average coating matrix thickness to the average particle size
ranges from about 0.6:1 to about 2:1.
14. The floor covering of claim 11 wherein the average coating
matrix thickness ranges from 4 .mu.m to 40 .mu.m.
15. The floor covering of claim 14 wherein the average coating
matrix thickness ranges from 6 .mu.m to 20 .mu.m.
116. The floor covering of claim 11 wherein the second abrasion
resistant particles are aluminum oxide.
17. The floor covering of claim 11 wherein the second abrasion
resistant particles are feldspar.
18. A method of forming a multi-layer floor covering comprising: a)
Providing a first coating composition comprising a first curable
binder and a first curing initiator and a second coating
composition comprising a second curable binder and a second curing
initiator b) applying a first layer of the first coating
composition on a substrate, the first layer applied such that the
first coating composition exhibits a first average coating
thickness as measured from a top surface and a bottom surface of
the first layer; c) partially or fully curing the first coating
composition; d) applying a second layer of the second coating
composition on the top surface of the first layer, the second layer
applied such that the second coating composition exhibits a second
average coating thickness as measured from a top surface and a
bottom surface of the second layer; e) partially or fully curing
the second coating composition; wherein at least one of the first
and the second coating compositions comprise abrasion resistant
particles that include diamond particles and second abrasion
resistant particle having a Mohs hardness value of at least 6, the
diamond particle having an average particle size and being present
relative to the second abrasion resistant particles are particles
other than diamond particles, wherein the first abrasion resistant
particles and the second abrasion resistant particles are in a
weight ratio ranging from about 1:1 to about 1:8; wherein for each
of the first and second coating compositions that contain the
abrasion resistant particles, a ratio for each of the first average
coating thickness and the second average coating thickness to the
average particle size of the diamond particle ranges from 0.6:1 to
2:1; and wherein for each of the first and the second coating
compositions that contain the abrasion resistant particles, the
curing of the first and the second coating compositions results in
the diamond particle being vertically offset from at least one of
the respective bottom surfaces of the first and the second coating
compositions by a length greater than zero.
Description
FIELD OF INVENTION
[0001] Embodiments of the present invention relate to an abrasion
resistant coating for flooring tiles and panels, methods for
preparing and applying the abrasion resistant coating, and flooring
systems comprising the abrasion resistant coating.
BACKGROUND
[0002] Heretofore, curable coating compositions have been used as
overcoat materials to cover the surface of flooring products or
various abrasion heavy surfaces to protect such a products or
surfaces from damage by abrasion or scratch. However, previous
attempts at creating abrasion resistant coatings have required
large amounts of abrasion resistant particle--namely only aluminum
oxide--and have failed to appreciate a combination of hard
particles as well as the size distribution of abrasion resistant
particles, thereby leading to inefficient usage of abrasion
resistant filler in coatings.
SUMMARY
[0003] Some embodiments of the present invention are directed to a
floor covering comprising a substrate and a coating layer. The
coating layer may comprise a coating matrix and a mixture of
abrasion resistant particles. The coating matrix may be formed from
a curable coating composition comprising a binder. The coating
matrix has an average coating matrix thickness. The mixture of
abrasion resistant particles may comprise first abrasion resistant
particles and second abrasion resistant particles. The first
abrasion resistant particles have an average first particle size
and a narrow distribution of first particle sizes. According to
some embodiments, the narrow distribution of first particle sizes
having a standard deviation less than 35% of the first average
particle size. The first abrasion resistant particle is diamond
particle. According to some embodiments, the second abrasion
resistant particles are other than diamond particles and have a
Mohs hardness value of at least (equal to or higher than) 6. The
second abrasion resistant particle may be present relative to the
first abrasion resistant particle in a weight ratio ranging from
1:1 to 8:1. According to some embodiments, a ratio of the average
coating matrix thickness to first average particle size may range
from 0.6:1 to 2:1.
[0004] According to some embodiments, the present invention is
directed to a floor covering comprising a substrate and a coating
layer. The coating layer may comprise a coating matrix and abrasion
resistant particles. The coating matrix may be formed from a
curable coating composition comprising a binder. The coating matrix
comprising an average coating matrix thickness. The abrasion
resistant particles may comprise first abrasion resistant particles
and second abrasion resistant particles. The first abrasion
resistant particles may have an average particle size ranging from
2 .mu.m to 50 .mu.m and may be diamond particle. The second
abrasion resistant particles may have a Mohs hardness value of at
least 6. An average distance between two adjacently placed first
abrasion resistant particles may range from 20 .mu.m to 75 .mu.m,
which is measured between the centers of the adjacent
particles.
[0005] According to some embodiments, the present invention is
directed to a method of forming a multi-layer floor covering. The
method first comprises providing a first coating composition and a
second coating composition. The first coating composition comprises
a first curable binder and a first curing initiator and the second
coating composition comprises a second curable binder and a second
curing initiator. The method may further comprise applying a first
layer of the first coating composition on a substrate. The first
layer may be applied such that the first coating composition
exhibits a first average coating thickness. The first coating
composition may then be partially or fully cured. The method
further comprises applying a second layer of the second coating
composition on the top surface of the first layer. The second layer
may be applied such that the second coating composition exhibits a
second average coating thickness. The second coating composition
may then be partially or fully cured.
[0006] According to some embodiments of the present invention, the
method may further provide that at least one of the first and the
second coating compositions comprise abrasion resistant particles.
The abrasion resistant particles include diamond particles and
second abrasion resistant particles having a Mohs hardness value of
at least 6. According to some embodiments, the diamond particles
have an average particle size and is present relative to the second
abrasion resistant particles in a weight ratio ranging from about
1:1 to about 1:8.
[0007] According to some embodiments, for each of the first and the
second coating compositions that contain the abrasion resistant
particles, a ratio for each of the first average coating thickness
and the second average coating thickness to the average particle
size of the diamond particle ranges from 0.6:1 to 2:1. According to
other embodiments, for each of the first and the second coating
compositions that contain the abrasion resistant particles, the
curing of the first and the second coating compositions results in
the diamond particle being vertically offset from at least one of
the respective bottom surfaces of the first and the second coating
compositions by a length greater than zero.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The features of the exemplary embodiments of the present
invention will be described with reference to the following
drawings, where like elements are labeled similarly, and in
which:
[0009] FIG. 1 is a cross-sectional view of the floor covering
according to one embodiment of the present invention;
[0010] FIG. 2 is a cross-sectional view of the floor covering
according to another embodiment of the present invention;
[0011] FIG. 3 is a cross-sectional view of the floor covering
according to another embodiment of the present invention;
[0012] All drawings are schematic and not necessarily to scale.
Parts given a reference numerical designation in one figure may be
considered to be the same parts where they appear in other figures
without a numerical designation for brevity unless specifically
labeled with a different part number and described herein.
DETAILED DESCRIPTION
[0013] The present invention is directed to floor coverings
comprising a substrate and an abrasion resistant coating layer. The
abrasion resistant coating layer may comprise coating matrix and
abrasion resistant particles. The coating matrix may be a curable
coating composition comprising a binder. According to some
embodiments, the binder may comprise acrylate-functional compounds
and the abrasion resistant particles comprise a mixture of diamond
particles and second abrasion resistant particles.
[0014] According to some embodiments of the present invention, the
binder may comprise resin selected from acrylate-functional
polymer, acrylate-functional oligomer, acrylate-functional monomer,
and combinations thereof. The acrylate-functional polymer may
include polyester acrylate, polyurethane acrylate, polyether
acrylate, polysiloxane acrylate, polyolefin acrylate, and
combinations thereof.
[0015] In some embodiments, the polyester acrylate according to the
present invention may be a linear or branched polymer having at
least one acrylate or (meth)acrylate functional group. In some
embodiments, the polyester acrylate of the present invention has at
least 1 to 10 free acrylate groups, (meth)acrylate groups, or a
combination thereof.
[0016] In some embodiments, the polyester acrylate has an acrylate
functionality The polyester acrylate may be the reaction product of
polyester polyol and an carboxylic acid functional acrylate
compound such as acrylic acid, (meth)acrylic acid, or a combination
thereof at a OH:COOH ratio of about 1:1. The polyester polyol may
be a polyester diol having two hydroxyl groups present at terminal
end of the polyester chain. In some embodiments, the polyester
polyol may have a hydroxyl functionality ranging from 3 to 9,
wherein the free hydroxyl groups are present at the terminal ends
of the polyester chain or along the backbone of the polyester
chain.
[0017] In non-limiting embodiments, the polyester polyol may be the
reaction product of a hydroxyl-functional compound and a carboxylic
acid functional compound. The hydroxyl-functional compound is
present in a stoichiometric excess to the carboxylic-acid compound.
In some embodiments the hydroxyl-functional compound is a polyol,
such a diol or a tri-functional or higher polyol (e.g. triol,
tetrol, etc.). In some embodiments the polyol may be aromatic,
cycloaliphatic, aliphatic, or a combination thereof. In some
embodiments the carboxylic acid-functional compound is dicarboxylic
acid, a polycarboxylic acid, or a combination thereof. In some
embodiments, the dicarboxylic acid and polycarboxylic acid may be
aliphatic, cycloaliphatic, aromatic.
[0018] In some embodiments the diol may be selected from alkylene
glycols, such as ethylene glycol, propylene glycol, diethylene
glycol, dipropylene glycol, triethylene glycol, tripropylene
glycol, hexylene glycol, polyethylene glycol, polypropylene glycol
and neopentyl glycol; hydrogenated bisphenol A; cyclohexanediol;
propanediols including 1,2-propanediol, 1,3-propanediol, butyl
ethyl propanediol, 2-methyl-1,3-propanediol, and
2-ethyl-2-butyl-1,3-propanediol; butanediols including
1,4-butanediol, 1,3-butanediol, and 2-ethyl-1,4-butanediol;
pentanediols including trimethyl pentanediol and
2-methylpentanediol; cyclohexanedimethanol; hexanediols including
1,6-hexanediol; caprolactonediol (for example, the reaction product
of epsilon-caprolactone and ethylene glycol); hydroxy-alkylated
bisphenols; polyether glycols, for example, poly(oxytetramethylene)
glycol. In some embodiments, the tri-functional or higher polyol
may be selected from trimethylol propane, pentaerythritol,
di-pentaerythritol, trimethylol ethane, trimethylol butane,
dimethylol cyclohexane, glycerol and the like.
[0019] In some embodiments the dicarboxylic acid may be selected
from adipic acid, azelaic acid, sebacic acid, succinic acid,
glutaric acid, decanoic diacid, dodecanoic diacid, phthalic acid,
isophthalic acid, 5-tert-butylisophthalic acid, tetrahydrophthalic
acid, terephthalic acid, hexahydrophthalic acid,
methylhexahydrophthalic acid, dimethyl terephthalate,
2,5-furandicarboxylic acid, 2,3-furandicarboxylic acid,
2,4-furandicarboxylic acid, 3,4-furandicarboxylic acid,
2,3,5-furantricarboxylic acid, 2,3,4,5-furantetracarboxylic acid,
cyclohexane dicarboxylic acid, chlorendic anhydride,
1,3-cyclohexane dicarboxylic acid, 1,4-cyclohexane dicarboxylic
acid, and anhydrides thereof, and mixtures thereof. In some
embodiments the polycarboxylic acid may be selected from
trimellitic acid and anhydrides thereof.
[0020] In some embodiments, the acrylate-functional polyurethane
according to the present invention may be a linear or branched
polymer having at least one functional group selected from an
acrylate group or a (meth)acrylate group. In some embodiments, the
acrylate-functional polyurethane may has at least 2 to 9 functional
groups selected from an acrylate group, a (meth)acrylate group, or
a combination thereof. In some embodiments, the acrylate-functional
polyurethane has between 2 and 4 functional groups selected from an
acrylate group, (meth)acrylate group, or a combination thereof.
[0021] In some embodiments, the acrylate functional polyurethane
may be the reaction product of a high molecular weight polyol and
diisocyanate, polyisocyanate, or a combination thereof. The high
molecular weight polyol may be selected from polyester polyol,
polyether polyol, polyolefin polyol, and a combination thereof--the
high molecular weight polyol having a hydroxyl functionality
ranging from 3 to 9.
[0022] In some embodiments, the polyester polyol used to create the
acrylate-functional polyurethane is the same as used to create the
acrylate functional polyester. In some embodiments, the polyether
polyol may be selected from polyethylene oxide, polypropylene
oxide, polytetrahydrofuran, and mixtures and copolymers
thereof.
[0023] The high molecular weight polyol may be reacted with
polyisocyanate, such as a diisocyanate, a tri-functional isocyanate
(e.g. isocyanurate), higher functional polyisocyanates, or a
combination thereof in an NCO:OH ratio ranging from about 2:1 to
4:1. The polyisocyanate may be selected from isophorone
diisocyanate, 4,4'-dicyclohexylmethane-diisocyanate, and
trimethyl-hexamethylene-diisocyanate, 1,6 hexamethylene
diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate,
octadecylene diisocyanate and 1,4 cyclohexylene diisocyanate.
toluene diisocyanate; methylenediphenyl diisocyanate; tetra
methylxylene diisocyanate, and isocyanurates, biurets, allophanates
thereof, as well as mixtures thereof. The resulting reaction
product is an isocyanate-terminated prepolymer.
[0024] The isocyanate-terminated prepolymer is then reacted with
hydroxyl-functional acrylate compound in an NCO:OH ratio of about
1:1 to yield an acrylate or (meth)acrylate functional polyurethane.
The hydroxyl-functional acrylate compounds may include hydroxyethyl
acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate,
hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl
methacrylate, hydroxypentyl acrylate, hydroxypentyl methacrylate,
hydroxyhexyl acrylate, hydroxyhexyl methacrylate, aminoethyl
acrylate, and aminoethyl methacrylate, and a combination
thereof.
[0025] According to some embodiments of the present invention, the
binder may comprise acrylate-functional oligomers that include
mono-functional oligomers, di-functional oligomers, tri-functional
oligomers, tetra-functional oligomers, penta-functional oligomers,
and combinations thereof.
[0026] In some non-limiting embodiments the mono-functional
oligomers may be selected from alkoxylated tetrahydrofurfuryl
acrylate; alkoxylated tetrahydrofurfuryl methylacrylate;
alkoxylated tetrahydrofurfuryl ethylacrylate; alkoxylated phenol
acrylate; alkoxylated phenol methylacrylate; alkoxylated phenol
ethylacrylate; alkoxylated nonylphenol acrylate; alkoxylated
nonylphenol methylacrylate; alkoxylated nonylphenol ethylacrylate,
and mixtures thereof. The alkoxylation may be performed using
ethylene oxide, propylene oxide, butylene oxide, or mixtures
thereof. In some embodiments the degree of alkoxylation ranges from
about 2 to 10. In some embodiments, the degree of alkoxylation
ranges from about 4 to 6.
[0027] In some non-limiting embodiments the di-functional oligomers
may be selected from ethylene glycol diacrylate, propylene glycol
diacrylate, diethylene glycol diacrylate, dipropylene glycol
diacrylate, triethylene glycol diacrylate, tripropylene glycol
diacrylate, polyethylene glycol diacrylate, polypropylene glycol
diacrylate, ethoxylated bisphenol A diacrylate, bisphenol A
diglycidyl ether diacrylate, resorcinol diglycidyl ether
diacrylate, 1,3-propanediol diacrylate, 1,4-butanediol diacrylate,
1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl
glycol diacrylate, cyclohexane dimethanol diacrylate, ethoxylated
neopentyl glycol diacrylate, propoxylated neopentyl glycol
diacrylate, ethoxylated cyclohexanedimethanol diacrylate,
propoxylated cyclohexanedimethanol diacrylate, and mixtures
thereof.
[0028] In some non-limiting embodiments, the tri-functional
oligomers may be selected from trimethylol propane triacrylate,
isocyanurate triacrylate, glycerol triacrylate, ethoxylated
trimethylolpropane triacrylate, propoxylated trimethylolpropane
triacrylate, tris (2-hydroxyethyl) isocyanurate triacrylate,
ethoxylated glycerol triacrylate, propoxylated glycerol
triacrylate, pentaerythritol triacrylate, melamine triacrylates,
and mixtures thereof.
[0029] In some non-limiting embodiments, the acrylate-functional
monomer may be selected from acrylic acid, methacrylic acid, ethyl
acrylic acid, 2-phenoxyethyl acrylate; 2-phenoxyethyl
methylacrylate; 2-phenoxyethyl ethylacrylate; tridecryl acrylate;
tridecryl methylacrylate; tridecryl ethylacrylate; and mixtures
thereof.
[0030] Some embodiments of the present invention may further
include acrylate functional monomers selected from alkyl acrylates
having up to about 12 carbon atoms in the alkyl segment such as
ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, amyl
acrylate, n-lauryl acrylate, nonyl acrylate, n-octyl acrylate,
isooctyl acrylate, isodecyl acrylate, etc.; alkoxyalkyl acrylates
such as methoxybutyl acrylate, ethoxyethyl acrylate, ethoxypropyl
acrylate, etc.; hydroxyalkyl acrylates such as hydroxyethyl
acrylate, hydroxybutyl acrylate, etc.; alkenyl acrylates such as
trimethoxyallyloxymethyl acrylate, allyl acrylate, etc.; aralkyl
acrylates such as phenoxyethyl acrylate, benzyl acrylate, etc.;
cycloalkyl acrylates such as cyclohexyl acrylate, cyclopentyl
acrylate, isobornyl acrylate, etc.; aminoalkyl acrylates such as
diethylaminoethyl acrylate; cyanoalkyl acrylates such as cyanoethyl
acrylate, cyanopropyl acrylate, etc.; carbamoyloxy alkyl acrylates
such as 2-carbamoyloxyethyl acrylate, 2-carbamoyl-oxypropyl
acrylate, N-methylcarbamoyloxyethyl acrylate,
N-ethylcarbamoyloxymethyl acrylate, 2-(N-methylcarbamoyloxy)-ethyl
acrylate, 2-(N-ethylcarbamoyloxy)ethyl acrylate, etc.; and the
corresponding methacrylates. In some embodiments, the alkyl
acrylates having up to about 12 carbon atoms in the alkyl segment
may be used as a reactive solvent/diluent in the abrasions
resistant coating layer.
[0031] The acrylate-functional monomers may include the binder may
comprise resin selected from acrylate-functional polymer,
acrylate-functional oligomer, acrylate-functional monomer, a
[0032] In some non-limiting embodiments, the acrylate-functional
monomer may be selected from acrylic acid, methacrylic acid, ethyl
acrylic acid, 2-phenoxyethyl acrylate; 2-phenoxyethyl
methylacrylate; 2-phenoxyethyl ethylacrylate; tridecryl acrylate;
tridecryl methylacrylate; tridecryl ethylacrylate; and mixtures
thereof.
[0033] In some embodiments, the acrylate-functional monomer or
oligomer is a silicone acrylate. Curable silicone acrylates are
known and suitable silicone acrylates are disclosed, for example in
U.S. Pat. No. 4,528,081 and U.S. Pat. No. 4,348,454. Suitable
silicone acrylates include silicone acrylates having mono-, di-,
and tri-acrylate moieties. Suitable silicone acrylates include, for
example, Silcolease.RTM. UV RCA 170 and UV Poly 110, available from
Blue Star Co. Ltd, China; and Silmer ACR D2, Silmer ACR Di-10,
Silmer ACR Di-50 and Silmer ACR Di-100, available from Siltech.
[0034] The coating matrix may further comprise photoinitiator to
facilitate UV curing of the curable coating composition. In some
non-limiting embodiments, the photoinitiators may include a benzoin
compound, an acetophenone compound, an acylphosphine oxide
compound, a titanocene compound, a thioxanthone compound or a
peroxide compound, or a photosensitizer such as an amine or a
quinone. Specific examples photoinitiatiors include
1-hydroxycyclohexyl phenyl ketone, benzoin, benzoin methyl ether,
benzoin ethyl ether, benzoin isopropyl ether, benzyl diphenyl
sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile,
dibenzyl, diacetyl and beta-chloroanthraquinone. In some
embodiments, the photoinitators are water soluble alkylphenone
photoinitiators.
[0035] The coating matrix may further comprise an amine synergist.
In some embodiments, the amine synergist may include
diethylaminoethyle methacrylate, dimethylaminoethyl methacrylate,
N--N-bis(2-hydroxyethyl)-P-toluidine, Ethyl-4-dimethylamino
benzoate, 2-Ethylhexyl 4-dimethylamino benzoate, as well as
commercially available amine synergist, including Sartomer CN 371,
CN373, CN383, CN384 and CN386; Allnex Ebecry P104 and Ebecry P115.
The amine synergist may be present in the radiation curable coating
composition by an amount ranging from about 1 wt. % to about 5 wt.
%, preferably about 3 wt. %
[0036] The coating layer of the present invention includes abrasion
resistant particles that help impart wear and scratch resistance to
the overall coating layer. The improved wear and scratch resistance
extends the life span of the floor covering. Examples of previous
attempts to use abrasion resistant particles to improve wear and
scratch resistance of flooring products include using only aluminum
oxide particles. According to the present invention, the abrasion
resistant particles include a combination of abrasion resistant
particles, each exhibiting a Mohs hardness value ranging from 6 to
10--including all integers therebetween, as measured on the Mohs
scale of mineral hardness. In some embodiments, the abrasion
resistant particles may be selected from diamond (Mohs value of
10), aluminum oxide (Mohs value of 9), topaz (Mohs value of 8),
quartz (Mohs value of 7), nepheline syenite or feldspar (Mohs value
of 6), and combinations thereof. The abrasion resistant particle
may be a combination of a first abrasion resistant particle
consisting of diamond particles and a second abrasion resistant
particle having a Mohs value of less than 10. In some embodiments,
the coating layer of the present invention may comprise an amount
of abrasion resistant particle ranging from about 6 wt. % to about
25 wt. % based on the total weight of the coating layer. In some
embodiments, the coating layer of the present invention may
comprise an amount of abrasion resistant particle ranging from
about 6 wt. % to about 12 wt. % based on the total weight of the
coating layer.
[0037] According to some embodiments, the second abrasion resistant
particle may be present relative to the diamond particle in a
weight ratio ranging from about 1:1 to about 10:1. In some
non-limiting embodiments, the second abrasion resistant particle is
present relative to the diamond particle in a weight ratio of about
1:1. In some non-limiting embodiments, the second abrasion
resistant particle is present relative to the diamond particle in a
weight ratio of about 2:1. In some non-limiting embodiments, the
second abrasion resistant particle is present relative to the
diamond particle in a weight ratio of about 4:1. In some
non-limiting embodiments, the second abrasion resistant particle is
present relative to the diamond particle in a weight ratio of about
8:1. It has been found that coating layers comprising a mixture of
diamond particles and second abrasion resistant particle of the
present invention (e.g., aluminum oxide particles) exhibits similar
abrasion resistance at much lower overall loading levels of
abrasion resistant particles compared to coating layers comprising
abrasion resistant particles of only aluminum oxide.
[0038] According to some embodiments, the abrasion resistant
particle is a combination of diamond particle and aluminum oxide
particles. According to some embodiments, the aluminum oxide
particles may have a variety of particle sizes including a mixture
of different sized diamond particles. In some non-limiting
embodiments, the aluminum oxide particles of the present invention
may have an average particle size that is selected from the range
of about 2 .mu.m to about 30 .mu.m. In some non-limiting
embodiments, the diamond particles of the present invention may
have an average particle size that is selected from range of about
6 .mu.m about 25 .mu.m. The term "about" means+/-percentage change
of 5%. In some embodiments, a mixture of aluminum oxide
powder.sup.1 may be selected that has particle sizes at 50% size
distribution: .sup.1Commercially available Microgrit WCA aluminum
oxide powder
TABLE-US-00001 Sample Size (.mu.m) at 50% 1 1.77-2.25 2 2.09-2.77 3
2.97-3.85 4 3.72-4.74 5 5.6-6.75 6 7.05-8.5 7 9.06-11.13 8
12.4-14.66 9 16.92-20.6 10 23.6-27.45
[0039] In some embodiments, a mixture of aluminum oxide
powder.sup.2 may be selected that has particle sizes at 50% size
distribution: .sup.2Commercially available Fujimi PWA aluminum
oxide powder
TABLE-US-00002 Sample Size (.mu.m) at 50% 11 3.1 .+-. 0.3 12 4.7
.+-. 0.4 13 6.4 .+-. 0.5 14 8.2 .+-. 0.6 15 10.2 .+-. 0.8 16 14.2
.+-. 1.1 17 17.4 .+-. 1.3 18 20.8 .+-. 1.5 19 25.5 .+-. 1.7 20 29.7
.+-. 20
[0040] In some embodiments, the abrasion resistant particle is a
combination of diamond particle and feldspar particles. The
feldspar particle may be present relative to the diamond particle
in a weight ratio ranging from about 2:1 to about 5:1. In some
non-limiting embodiments, the feldspar particle is present relative
to the diamond particle in a weight ratio of about 4:1. In some
non-limiting embodiments, the feldspar particle is present relative
to the diamond particle in a weight ratio of about 2:1. In some
non-limiting embodiments, the feldspar particles of the present
invention may have an average particle size that is selected from
the range of about 2 .mu.m to about 30 .mu.m--including all
integers therebetween. It has been found that coating layers
comprising a mixture of diamond particles and feldspar particles
may exhibit similar abrasion resistance at much lower overall
loading levels of abrasion resistant particles compared to coating
layers comprising abrasion resistant particles of only
feldspar.
[0041] According to some embodiments, the diamond particles
selected for the coating layer may have a variety of particle sizes
including a mixture of different sized diamond particles. However,
according to some embodiments, the diamond particles have a narrow
size distribution. According to this invention, the term narrow
size distribution means a standard deviation that is no more than
35%, preferably less than 35%, of the average particle size for a
given diamond particle blend or mixture. In some embodiments, the
standard deviation is less than 25% based on the average particle
size for a given diamond particle blend or mixture. In some
embodiments, the standard deviation is less than 15% based on the
average particle size for a given diamond particle blend or
mixture.
[0042] In some non-limiting embodiments, the diamond particles of
the present invention may have an average particle size that is
selected from the range of about 2 .mu.m to about 50 .mu.m,
preferably about 4 .mu.m to 35 .mu.m. In some non-limiting
embodiments, the diamond particles of the present invention may
have an average particle size that is selected from range of about
6 .mu.m about 25 .mu.m. The term "about" means+/-percentage change
of 5%.
[0043] In some non-limiting embodiments of the present invention,
the diamond particles may be a first mixture of diamond particles
that has particle sizes ranging from about 6 .mu.m to about 11
.mu.m, preferably from about 6 .mu.m to about 10 .mu.m--including
all integers therebetween and mixtures thereof. According to some
embodiments, the first mixture of diamond particles may include
diamond particles having an average particle size of about 6 .mu.m,
about 7 .mu.m, about 8 .mu.m, about 9 .mu.m, about 10 .mu.m, or 11
.mu.m.
[0044] In some embodiments, the first mixture of diamond particles
may have the following particle size distribution:
TABLE-US-00003 Distribution % 10 20 30 40 50 60 70 80 90 100 Size
(.mu.m) 6.04 6.61 7.03 7.43 7.83 8.27 8.77 9.4 10.45 11.46
Wherein the average particle size is represented at the 50%
distribution point (i.e. about 8 .mu.m) and the standard deviation
is about 1.7, making the standard deviation about 21% of the
average particle size.
[0045] It is possible that the first mixture may contain diamond
particle having particle sizes outside of the about 6 .mu.m to
about 10 .mu.m range so long as the standard deviation for the
first mixture is not greater than 35%, preferably less than 35%. In
some embodiments, it is possible that the first mixture may contain
diamond particle having particle sizes outside of the about 6 .mu.m
to about 10 .mu.m range so long as the standard deviation for the
first mixture is less than 25%, preferably less than 15%. In some
embodiments, the first mixture may contain up to 4 wt. % of diamond
particles having a particle size that is less than 6 .mu.m. In some
non-limiting embodiments, the first mixture may contain up to 4 wt.
% of diamond particles having a particle size that is less than 6
.mu.m. In some embodiments, the first mixture may contain up to
6.54 wt. % of diamond particles having a particle size that is
greater than 11 .mu.m.
[0046] In some non-limiting embodiments of the present invention,
the diamond particles may be a second mixture of diamond particles
that has particle sizes ranging from about 15 .mu.m to about 30
.mu.m, preferably about 15 .mu.m to about 25 .mu.m--including all
integers therebetween and mixtures thereof. According to some
embodiments, the second mixture of diamond particles may have an
average particle size of about 15 .mu.m, about 16 .mu.m, about 17
.mu.m, about 18 .mu.m, about 19 .mu.m, about 20 .mu.m, about 21
.mu.m, about 22 .mu.m, about 23 .mu.m, about 24 .mu.m, or about 25
.mu.m.
[0047] In some embodiments, the second mixture of diamond particles
may have the following particle size distribution:
TABLE-US-00004 Distribution % 10 20 30 40 50 60 70 80 90 100 Size
(.mu.m) 15.88 17.25 18.38 19.40 20.42 21.52 22.84 24.64 27.59
30.83
Wherein the average particle size is represented at the 50%
distribution point (i.e. about 20 .mu.m) and the standard deviation
is about 4.4, making the standard deviation about 22% of the
average particle size.
[0048] It is possible that the second mixture may contain diamond
particles having a particle size outside of the 15 .mu.m to 25
.mu.m range so long as the standard deviation for the second
mixture is not greater than 35%, preferably less than 35%. In some
non-limiting embodiments, it is possible that the second mixture
may contain diamond particles having a particle sizes outside of
the 15 .mu.m to 25 .mu.m range so long as the standard deviation
for the second mixture is less than 25%, preferably less than 15%.
In some non-limiting embodiments, the second mixture may contain up
to 3.25 wt. % of diamond particles having a particle size that is
less than 15 .mu.m. In some embodiments, the second mixture may
contain up to 8 wt. % of diamond particles having a particle size
that is greater than 30 .mu.m.
[0049] The coating layer of the present invention may comprise the
first abrasion resistant diamond particles in amount that ranges
from about 1 wt. % to about 5 wt. %, a based on the total weight of
the coating layer, preferably 2 wt. % to 4 wt. %. In some
embodiments, the coating layer may comprise about 1.75 wt. % to
about 3.7 wt. % of diamond particles. It has been discovered that
the coating layer of the present invention may exhibit the desired
scratch resistance and gloss retention properties when using
abrasion resistant particles that consist of only diamond particles
in the above recited amounts. It has also been found that exceeding
diamond particle loading amounts of 5.5 wt. %, there may be an
undesirable effect to the visual properties of the coating
layer.
[0050] As shown in FIGS. 1-3, the floor covering 1 of the present
invention includes a coating layer 3 and a substrate 2. The coating
layer 3 comprises abrasion resistant particles 20 and coating
matrix 10. The thickness of the coating layer may vary across the
top surface of the coating layer based on the surface topography
defined by the abrasion resistant particles 20 positioned within
the coating matrix 10. The coating matrix has a top surface 11 and
a bottom surface 12. The bottom surface 12 of the coating matrix 10
abuts the top surface 4 of the substrate 2, or in the case of
multi-layer floor coverings, the top surface of the underneath
coating layer (not pictured). The top surface 11 of the coating
matrix 10 is the upward exposed face that is uninterrupted between
protruding abrasion resistant particles 20 that are positioned in
the coating matrix 10.
[0051] The average coating matrix thickness T.sub.CM is the
vertical distance measure between the top surface 11 and bottom
surface 12 of the coating matrix 10. According to some embodiments,
the average matrix coating thickness T.sub.CM may range from about
4 .mu.m to about 40 .mu.m --including all integers therebetween.
According to some embodiments, the average matrix coating thickness
T.sub.CM may range from about 6 .mu.m to about 20 .mu.m--including
all integers therebetween. According to some embodiments, the
average matrix coating thickness T.sub.CM is 6 .mu.m. According to
some embodiments, the average matrix coating thickness T.sub.CM is
18 .mu.m.
[0052] According to some embodiments of the present invention, the
dimensions of the diamond particles and the coating matrix may be
selected such that a ratio of the average coating matrix thickness
T.sub.CM to average particle size D.sub.AP of the diamond particles
20 (the TD ratio) ranges from about 0.6:1 to about 2:1. In some
embodiments, the TD ratio of the average matrix coating thickness
T.sub.CM to the average particle size D.sub.AP of the diamond
particles 20 ranges from about 0.9:1 to 2:1.
[0053] In some embodiments of the present invention, the average
particle size D.sub.AP of the diamond particles 20 and the average
coating matrix thickness T.sub.CM may be outside of the previously
discussed size ranges so long as, together, the average coating
matrix thickness T.sub.CM and the average particle size D.sub.AP of
the diamond particles 20 satisfy the TD ratio of 0.6:1 to 2:1,
preferably from 0.9:1 to 2:1.
[0054] The TD ratio ranging from 0.6:1 to 2:1 provides that at
least some of the diamond particles 20 may protrude from the top
surface 11 of the coating matrix 10 by a first length L.sub.1 when
the TD ratio of coating matrix thickness T.sub.CM to average
particle size D.sub.AP of diamond particles 20 ranges from 0.6:1 to
0.99:1. According to some embodiments the first length L.sub.1 is a
distance equal to about 1% to about 43% of the average coating
matrix thickness T.sub.CM--including all integers therebetween.
[0055] The specific distance of the first length L.sub.1 will
depend on the specific size of the diamond particles 20 as well as
the average coating matrix thickness T.sub.CM. However, in some
embodiments the first length L.sub.1 may ranges from about 0.2
.mu.m to about 6 .mu.m (based on diamond particles 20 that have an
average particle size D.sub.AP of about 20 .mu.m). In alternative
embodiments, the first length L.sub.1 may range from 0.08 .mu.m to
about 2.5 .mu.m (based on diamond particles 20 having an average
particle size D.sub.AP of about 8 .mu.m).
[0056] Although not depicted by the figures, in some embodiments,
the TD ratio ranging from 0.9:1 to 1.1:1 would provide for at least
some of the diamond particles having a particle size about equal to
the average coating matrix thickness. In such embodiments, the
diamond particles are positioned within close proximity to the top
surface of the coating matrix.
[0057] As depicted in FIG. 2, using a TD ratio of about 1:1 to 2:1
would provide for at least some of the diamond particles 20 being
fully encompassed by the coating matrix 10. The resulting coating
layer 3 has the diamond particles 20 submerged under the top
surface 11 of the coating matrix 10 by a second length L.sub.2--as
measured from the top of the diamond particle 20 to the top surface
11 of the coating matrix 10. According to some embodiments the
second length L.sub.2 is a distance equal to about 1% to about 50%
of the average coating matrix thickness T.sub.CM--including all
integers therebetween.
[0058] The specific distance of the second length L.sub.2 will
depend on the particle size of the diamond particle 20 as well as
the average coating matrix thickness T.sub.CM. However, in some
embodiments the second length L.sub.2 may range from about 0.2
.mu.m to about 20 .mu.m (based on diamond particles 20 have an
average particle size D.sub.AP of about 20 .mu.m). In alternative
embodiments, the second length L.sub.2 may range from 0.08 .mu.m to
about 8 .mu.m (based on diamond particles 20 having an average
particle size D.sub.AP of about 8 .mu.m).
[0059] As depicted in FIG. 3, some embodiments of the present
invention provide that the UV curable coating matrix 10 may be
partially cured during or immediately after the application of the
coating layer 3. The partial curing secures the diamond particles
20 in place within the coating matrix 10 before the diamond
particles 20 are able to completely settle and drop to the bottom
surface 12 of the coating matrix 10. According to some embodiments,
partially curing the coating matrix can create a third length
L.sub.3 and a fourth length L.sub.4--the third length L.sub.3
measured from the top surface 11 of the coating matrix 10 to the
top of the diamond particle 20 and the fourth length L.sub.4 being
measured from the bottom surface of the diamond particle 20 to the
bottom surface 12 of the coating matrix 10.
[0060] The third length L.sub.3 may be equal to 5% to 95% of the
second length L.sub.2--including all integers therebetween. In some
embodiments the third length L.sub.3 is equal to about 50% of the
second length L.sub.2 The third length L.sub.3 may be created
without having to change the average particle size D.sub.AP of the
diamond particle 20 or the average coating matrix thickness
T.sub.CM. By partially curing the coating matrix 10 the downward
movement of the diamond particle 20 caused by gravitational pull is
stopped, and the diamond particle 20 is held in vertical position
before it can fully settled to the bottom surface 12 of the coating
matrix 10. Therefore, a corresponding gap is created between the
bottom of the diamond particle 20 and the bottom surface 12 of the
coating matrix 10--the gap being represented by a fourth length
L.sub.4. The sum of the third length L.sub.3 and fourth length
L.sub.4 is equal the second length L.sub.2 for a given average
particle size D.sub.AP and average coating matrix thickness
T.sub.CM.
[0061] In some embodiments, the coating matrix may further comprise
other additives and fillers, such as a surfactant, as pigments,
tackifiers, surfactant, matting agents, fillers such as glass or
polymeric bubbles or beads (which may be expanded or unexpanded),
hydrophobic or hydrophilic silica, calcium carbonate, glass or
synthetic fibers, blowing agents, toughening agents, reinforcing
agents, fire retardants, antioxidants, and stabilizers. The
additives are added in amounts sufficient to obtain the desired end
properties. Suitable surfactants of the present invention include,
but are not limited to, fluorinated alkyl esters, polyether
modified polydimethylsiloxanes and fluorosurfactants, having the
formula R.sub.fCH.sub.2CH.sub.2O(CH.sub.2CH.sub.2O).sub.xH, wherein
R.sub.f.dbd.F(CF.sub.2CF.sub.2).sub.y, x=0 to about 15, and y=1 to
about 7. The surfactant may be present in the radiation curable
adhesive composition by an amount ranging from about 0.5 wt. % to
about 2 wt. %, preferably about 0.8 wt. %.
[0062] In some non-limiting embodiments, the coating layer may be
produced according to the following master batch methodology. The
coating matrix is comprised of the binder, dispersing agent,
photoinitiator, and matting agent. The abrasion resistant particles
comprise diamond particles. The components making up the binder are
first combined and mixed together at room temperature with high
speed agitation. For the purposes of the present application. the
term high speed agitation means agitation with a blade at rotation
speeds of at least 2,000 RPM. A dispersing agent may be added
concurrently with the binder components or after the binder
components have been blended together. The dispersing agents may be
selected from acrylic block-copolymers, such as commercially
available BYK Disperbyk 2008, Disperbyk 2155, Disperbyk 145 and
Disperbyk 185, Lubrizol Solsperse 41000 and Solsperse 71000, and
may be present in the coating layer by an amount ranging from 0.1
wt. % to 1 wt. %.
[0063] Next, the photoinitiator is slowly added at room
temperature. In some alternative embodiments, the photoinitiator
may be added at 45.degree. C. with high speed agitation. Once the
photoinitiator is entirely dissolved into the master batch mixture,
matting agents and the abrasion resistant particles may be added.
The matting agent and abrasion resistant particles may be added to
the master batch as the final ingredients to the blend of coating
matrix and diamond particles. The matting agent and abrasion
resistant particles should be added slowly to avoid a powder layer
from forming and floating on top of coating matrix. Once added, the
binder, dispersing agent, photoinitiator, matting agent, and
abrasion resistant particles are mixed with high speed agitation
for a period ranging from about 5 to about 15 minutes, preferably
about 10 minutes. During the agitations, the blade may be moved up
and down to ensure proper mixing of the ingredients in the master
batch. The temperature of the master batch may increase during
agitation, therefore to prevent premature thermal curing of the
binder, the master batch may be cooled during agitation.
[0064] The fully blended coating matrix and diamond particles have
a viscosity ranging from about 600 cPs to about 1300 cPs at room
temperature (74.degree. F.) as measured by a Brookfield Viscometer
using spindle #6 at 100 RPM. In some embodiments of the present
invention, the viscosity allows the blend of coating matrix and
diamond particles to be applied to a substrate by roll coating at
room temperature. The substrates may selected from linoleum tile,
ceramic tile, natural wood planks, engineered wood planks, vinyl
tile--such as luxury vinyl tile ("LVT"), and resilient sheet--such
as homogenous or heterogeneous commercial resilient sheets and
residential resilient sheets. After applying the blend of coating
matrix and diamond particles to the substrate, the blend is exposed
to UV radiation in air or a nitrogen environment.
[0065] The UV radiation includes UVA, UVB, UVC, and UVV sources.
Non-limiting examples of UV partial cure radiation include UVA
radiation of 0.189 J/cm.sup.2; UVB radiation of 0.163 J/cm.sup.2;
UVC radiation of 0.01 J/cm.sup.2; and UVV radiation may be 0.092
J/cm.sup.2. The pre-cure temperature may be 30.degree.
C.-40.degree. C. and the coating composition may be exposed to the
UV radiation at a line speed ranging from about 25 to 75 FPM.
Non-limiting examples of UV full cure include UVA radiation of
1.006 J/cm.sup.2; UVB radiation of 0.886 J/cm.sup.2; UVC radiation
of 0.126 J/cm.sup.2; and UVV radiation may be 0.504 J/cm.sup.2. To
fully cure, the coating composition may be exposed to the UV
radiation at a line speed ranging from about 25 to 75 FPM. The
delay between the pre-cure/partial cure and the full cure ranges
from about 3 seconds to about 10 seconds. The fully cured coating
matrix containing the diamond particles forms the coating layer of
the floor covering.
[0066] As previously discussed, the UV curable coating matrix can
be partially cured in some embodiments to prevent the abrasion
resistant particles from fully settling within coating matrix. In
some embodiments, the floor covering may contain two or three
coating layers, each additional coating layer positioned on top of
the previously applied coating layer. According to this embodiment,
the additional coating layers may each be partially or fully cured
before application of the subsequent coating layer to prevent the
diamond particles of each coating layer from fully settling.
[0067] In some embodiments, the fully cured coating layer may have
an average coating thickness that ranges from about 4 .mu.m to
about 40 .mu.m. In some embodiments, the fully cured coating layer
may have an average coating thickness that ranges from about 6
.mu.m to about 20 .mu.m. The specific thickness of the coating
layer will depend on the average particle size of the abrasion
resistant particles, as previously discussed.
[0068] As shown in FIGS. 1-3, some embodiments provide that after
the coating layer 3 is applied to a substrate 2 and cured, the
diamond particles 20 dispersed throughout the coating matrix 10 and
spaced apart by an average separation distance Ds ranging from
about 20 .mu.m to about 75 .mu.m--including all integers
therebetween. In some embodiments the average separation distance
Ds ranges from about 30 .mu.m to about 65 .mu.m. In some
embodiments the average separation distance Ds ranges from about 32
.mu.m to about 62 .mu.m. The average separation distance Ds is
measured between the centers of the adjacent particles.
[0069] According to the present invention, the TD ratio of average
coating matrix thickness to average diamond particle size in
combination with each low standard deviation in diamond particles
sizes results in the coating layer having not only superior
abrasion resistance but also superior retention on the surface
finish of the coating layer, i.e. gloss. Specifically, there is
little variation in the first length of the diamond particles that
protrude from the top surface of the coating matrix. With such
regularity, the amount of protrusion becomes much better
controlled, thereby eliminating diamond particles that protrude too
far from the coating matrix. With fewer diamond particles
protruding too far from the coating matrix, there are less diamond
particles that may be inadvertently dislodged from the coating
matrix when a shear force (i.e. contact with a shoe) is applied to
the coating layer during use, thereby limiting the likelihood that
the abrasion resistance particles can be dislodged from the coating
matrix, which would not only result in an uneven surface finish of
the coating layer but the released abrasion resistant particles
would being free to abrade the top surface of the coating matrix,
thereby exacerbating the wear on the coating layer of the floor
covering. The degree of premature abrasion resistant particle
"pop-outs"would ultimately determine the wear rate of the coating
layer, and, therefore, the floor covering. Abrasions resistant
particles held firmly in place would create a more wear resistant
floor covering than a floor covering where the abrasions resistant
particles are popped out with relative ease and low shear
force.
[0070] It has also been discovered that the particle size
distribution provides for greater uniformity between particles
within the coating matrix, thereby enhancing the structural
integrity of the coating matrix within the coating layer. As a
result when shear force is applied to the coating layer during use
(e.g. contact with a shoe), the overall coating layer is less
likely to deform and can better withstand abrasion and maintain the
desired level of gloss. Surprisingly, it has been also found that
utilizing a coating having a TD ratio equal to or lager than 1 and
less than or equal to 2 improves abrasion resistance of the coated
surface, unlike the prior art understanding that the abrasion
resistant particles need to be protruded above the coating matrix
surface to provide abrasion resistance.
[0071] The present invention has been disclosed in conjunction with
UV curable coating compositions for illustration purposes only, and
other curable coating compositions such as moisture curable
compositions, 2K urethane coating compositions, epoxy coating
compositions, and acrylic coating compositions, can be
utilized.
[0072] The following examples were prepared in accordance with the
present invention. The present invention is not limited to the
examples described herein.
Examples
Experiment 1
[0073] A first set of tests were run to compare abrasion resistant
coatings consisting of only aluminum oxide as the abrasion
resistant particle as well as coatings that include abrasion
resistant particles comprising a mixture of aluminum oxide and
diamond. The abrasions resistant coatings were formed from coating
matrixes having a Binder 1 comprising: [0074] i. 25 grams of
Eternal EC6360--polyester acrylate; [0075] ii. 25 grams of Allnex,
EB8602--urethane acrylate; [0076] iii. 20 grams of tricyclodecane
dimethanol diacrylate; [0077] iv. 7 grams of trimethylolpropane
triacrylate; [0078] v. 10 grams of isobornyl acrylate; [0079] vi. 9
grams of 2-phenoxythyl acrylate; [0080] vii. 9 grams of hexanediol
diacrylate; and [0081] viii. 4 grams of BlueStar Silicon, Scla UV
RCA 170--silicon acrylate.
[0082] The resin was mixed with high speed agitation at room
temperature (74.degree. F.) with the addition of 0.5736 grams of
dispersing agent. The dispersing agent being BYK Disperbyk 2008--an
acrylic block-copolymer. Next 4.54 grams of amine synergist
(Sartomer CN 371) and 5.91 grams of photoinitiator were added with
high speed agitation until completely dissolved in the mixture. The
photoinitiator includes 4.73 grams of diphenyl ketone and 1.18
grams of 1-hydroxy-cyclohexyl phenyl ketone.
[0083] Next, 21.41 grams of matting agent and the various amounts
of abrasion resistant particles were added to each mixture of
Examples 0-5. The matting agent includes the following: [0084] i.
10.39 grams of Arkema, Orgasol 3501 EX D NAT1--a polyamide 6/12;
[0085] ii. 3.37 grams of MicroPowder Fluo HT having a particle size
ranging from 2 .mu.m to 4 .mu.m; and [0086] iii. 7.65 grams of
Evonik Acematt 3600--silica.
[0087] The matting agent and abrasion resistance particles are
added slowly, the mixture is agitated for at least 10 minutes with
high speed agitation. The diamond particles and aluminum oxide
particles are commercially available and obtained from Yusing Sino
Crytal Micron, LTD and Micro Abrasives Corp, respectively. After
the high speed agitation, the resulting curable coating composition
is discharged from the mixer and applied to a substrate by roll
coating. Once applied to the substrate, the curable coating
composition is cured by UV radiation, thereby forming the coating
layer of the floor covering.
TABLE-US-00005 TABLE 1 Ex. 0 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Binder 1
109 109 109 109 109 109 Amine Synergist 4.54 4.54 4.54 4.54 4.54
4.54 Photoinitiator 5.91 5.91 5.91 5.91 5.91 5.91 Matting Agent
21.41 21.41 21.41 21.41 21.41 21.41 Dispersing Agent 0.57 0.57 0.57
0.57 0.57 0.57 Aluminum Oxide (20 .mu.m) 0 0 0 0 5.45 0 Aluminum
Oxide (D50% 5.6 .mu.m-6.75 .mu.m).sup.3 0 5.45 10.68 35.42 0 10.9
Diamond (6 .mu.m-10 .mu.m).sup.4 0 0 0 0 0 2.72 Total (weight in
grams) 141.43 146.88 152.112 176.86 146.88 155.06 Viscosity (cPs)
850 890 1025 1750 950 915 Note: * viscosity at room temperature
(74.degree. F.) as measured by a Brookfield Viscometer using
spindle #6 at 100 RPM .sup.3Aluminum oxide particles having a D50%
of 5.6 .mu.m-6.75 .mu.m; D94% MIN of 1.36 .mu.m; and D3% MAX of
13.47 .mu.m .sup.4Diamond particles having an average particle size
of 8 .mu.m and a standard deviation of 1.7
[0088] Each coating layer was then abraded with 30 passes using 100
grit sand paper and applying 50 g weight. A Gardner abrasion tester
was used, which is available from BYK Gardner. After abrading, each
sample was visually compared by a panel of eight test evaluators
for retention of desired visual appearance--wherein the rank of
visual appearance was calculated on a scale of 0 to 1. A value of 0
being the best (i.e. having minimal abrasion) and a value of 1
being the worst (i.e. having visually significant and noticeable
abrasions. The results are provided in Table 2. .sup.3Aluminum
oxide particles having a D50% of 5.6 .mu.m-6.75 .mu.m; D94% MIN of
1.36 .mu.m; and D3% MAX of 13.47 .mu.m.sup.4Diamond particles
having an average particle size of 8 .mu.m and a standard deviation
of 1.7
TABLE-US-00006 TABLE 2 Scratch Resistance and Gloss Retention Ex. 0
Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Flat White Tile 0.97 0.75 0.77 0.57
0.59 0.26 Lt Wood LVT 0.87 0.55 0.98 0.71 0.62 0.34 DK Wood LVT
0.83 0.8 0.67 0.92 0.49 0.4 Engineered Wood 0.9 0.76 0.76 0.92 0.56
0.3 Average 0.89 0.72 0.8 0.78 0.57 0.33
[0089] The coating layers containing a mixture of aluminum oxide
and diamond particles not only performed better than the coating
layers containing aluminum oxide particles, but the diamond
particles in combination with the aluminum oxide allowed for much
less overall loading of aluminum oxide particles in the coating
layer while still maintaining the desired abrasion resistance
properties. Furthermore, the coating composition further comprising
diamond particles not only provided significantly improved
abrasion-resistance, but also without increasing the viscosity of
the coating composition, making the coating composition easier to
apply.
Experiment 2
[0090] A second set of tests were run to compare abrasion resistant
coatings comprising abrasion resistant particles of aluminum oxide
and diamond at different loading amounts using a UV curable binder
(PPG R30983MF--"Binder 2"), which is a UV curable acrylate coating
binder, available from PPG. The abrasions resistant coatings
contained the following abrasion resistant particle
formulations:
TABLE-US-00007 TABLE 3 Ex. 6 Ex. 7 Ex. 8 Ex. 9 Ex. 10 Ex. 11 Ex. 12
Ex. 13 Ex. 14 Ex. 15 Binder 2 100 100 100 100 100 100 100 100 100
100 Aluminum Oxide (20 .mu.m) 0 4.0 8.0 12.0 16.0 24.0 4.0 4.0 8.0
8.0 Diamond (6 .mu.m-10 .mu.m).sup.5 0 0 0 0 0 0 0 0 0 0 Diamond
(15 .mu.m-25 .mu.m).sup.6 0 0 0 0 0 0 4.0 2.0 2.0 1.0 Total (weight
in grams) 100 104 108 112 116 124 108 112 116 124 Viscosity (cPs)
700 750 800 860 975 1250 775 750 825 800 Note: * viscosity at room
temperature (74.degree. F.) as measured by a Brookfield Viscometer
using spindle #6 at 100 RPM .sup.5Diamond particles having an
average particle size of 8 .mu.m and a standard deviation of 1.7
.sup.6Diamond particles having an average particle size of 20 .mu.m
and a standard deviation of 4.4
[0091] Each coating layer was then abraded with 30 passes using 100
grit sand paper and applying 2.1 pound weight. After abrading, each
sample was compared for retention of desired visual
appearance--wherein the rank of visual appearance was calculated on
a scale of 0 to 1. A value of 0 being the best and a value of 1
being the worst. The results are provided in Table 4.
TABLE-US-00008 TABLE 4 Scratch Resistance and Gloss Retention Ex. 6
Ex. 7 Ex. 8 Ex. 9 Ex. 10 Ex. 11 Ex. 12 Ex. 13 Ex. 14 Ex. 15
Homogenous Resilient Commercial Vinyl Sheet 0.97 0.79 0.91 0.66
0.74 0.48 0.41 0.29 0.36 0.51
[0092] The coating layers containing a combination of aluminum
oxide particles and diamond particles not only performed better
than the coating layers containing only aluminum oxide particles,
but the diamond particles allowed for much less overall loading the
aluminum oxide particles in the coating layer. Furthermore, for
example, Example 12 demonstrates that the combination of aluminum
oxide particles with diamond particles provided for superior
abrasion resistance and gloss retention when relatively less
aluminum oxide particles were used relative to other aluminum
oxide/diamond particle combinations--thereby providing superior
coating performance at less overall loading amounts of abrasion
resistant particles.
Experiment 3
[0093] A third set of tests were run to compare abrasion resistant
coating layers comprising abrasion resistant particles of nepheline
syenite ("feldspar") and abrasion resistant coating layers
comprising abrasion resistant particles of feldspar and diamond.
The feldspar has a Mohs Hardness of 6 and the diamond has a Mohs
Hardness of 10. Each coating layer of the floor covering being a
medium gloss ("MG") coating layer. The abrasions resistant coatings
were formed from coating matrixes having a Binder 3 comprising:
[0094] i. 17.5 grams of Eternal EC6360--polyester acrylate; [0095]
ii. 32.5 grams of Allnex, EB8602--urethane acrylate; [0096] iii. 20
grams of tricyclodecane dimethanol diacrylate; [0097] iv. 7 grams
of trimethylolpropane triacrylate; [0098] v. 10 grams of isobornyl
acrylate; [0099] vi. 9 grams of 2-phenoxythyl acrylate; [0100] vii.
9 grams of hexanediol diacrylate; and [0101] viii. 2 grams of
BlueStar Silicon, Scla UV RCA 170--silicon acrylate.
[0102] The resin was mixed with high speed agitation at room
temperature (74.degree. F.) with the addition of 0.8025 of
dispersing agent. The dispersing agent being BYK Disperbyk 2008--an
acrylic block-copolymer. Next 4.46 grams of amine synergist
(Sartomer CN 371) and 5.8 grams of photoinitiator were added with
high speed agitation until completely dissolved in the mixture. The
photoinitiator includes 4.64 grams of diphenyl ketone and 1.16
grams of 1-hydroxy-cyclohexyl phenyl ketone. The photoinitiator may
be added at room temperature of 45.degree. C. with the aid of high
speed agitation.
[0103] Next, 5.4 grams of matting agent and the various amounts of
abrasion resistant particles were added to each mixture of Examples
0-6. The matting agent includes the following: [0104] i. 2.39 grams
of Arkema, Orgasol 3501 EX D NAT1--a polyamide 6/12; and [0105] ii.
3.01 grams of MicroPowder Polyfluo 523 XF having a particle size
ranging from 3 .mu.m to 6 .mu.m.
[0106] The matting agent and abrasion resistance particles are
added slowly, the mixture is agitated for at least 10 minutes with
high speed agitation in accordance with the amounts set forth in
Examples 15-18 shown in Table 5. After the high speed agitation,
the resulting curable coating composition is discharged from the
mixer and applied to a substrate by roll coating to a thickness of
about 6 .mu.m. Once applied to the substrate, the curable coating
composition is cured by UV radiation, thereby forming the MG
coating layers of the floor covering.
TABLE-US-00009 TABLE 5 Ex. 16 Ex. 17 Binder 2 107 107 Amine
Synergist 4.46 4.46 Photoinitiator 5.8 5.8 Matting Agent 5.4 5.4
Dispersing Agent 0.8025 0.8025 Diamond (6 .mu.m-10 .mu.m).sup.7 0.0
5.35 Feldspar Particle.sup.8 10.7 10.7 Total 134.17 139.52
.sup.7Diamond particles having an average particle size of 8 .mu.m
and a standard deviation of 1.7 .sup.8Commercially available Minex
3 from Unimin
[0107] The cured MG coating layers were tested with a Gardner
Abrasion tester, available from BYK Gardner, for the level of gloss
retained using 100 grit sand paper and applied weight of 2.1 pound
with 30 passes. Each sample as analyzed for percentage of gloss
retention and .DELTA.b color change value. The results are provided
in Table 6.
TABLE-US-00010 TABLE 6 Gloss Retention % .DELTA.b Color Value Ex.
16 36 1.27 Ex. 17 94 1.95
[0108] According to Chart 1, each of the MG coating layers exhibit
a gloss retention after the scratch test of at least 70%. The gloss
retention begins to worsen as the amount of diamond particles
becomes greater than 6 wt. %. Furthermore, as shown in Chart 2, the
color value--as represented by .DELTA.b value--increases with
corresponding increases in the amount of diamond particles in the
MG coating layer. For the purposes of this invention, it is
desirable that the color .DELTA.b value remain as low as possible
because higher .DELTA.b values result in a MG coating layer having
a yellow appearance. Therefore, it has been discovered that at
diamond particle loading amounts ranging between 2 wt. % and under
6 wt. %--preferably 5.5 wt. %--the resulting MG coating layer not
only exhibits desirable abrasion resistance and gloss retention
properties, but also will not exhibit a color .DELTA.b value that
interferes with the desired aesthetic appearance of the MG coating
layer.
[0109] Delta b (.DELTA.b) or difference in b values between the
control and a sample indicates the degree of yellowing. The degree
of yellowing is measured by use of a calorimeter that measures
tristimulas color values of `a`, `b`, and `L`, where the color
coordinates are designated as +a (red), -a (green), +b (yellow), -b
(blue), +L (white), and -L (black).
Experiment 4
[0110] A fourth set of tests were run to compare different loading
amounts of the diamond particles within the coating layer of the
floor covering--the coating layer being a low gloss ("LG") coating
layer. The LG abrasions resistant coatings were formed from coating
matrixes having a Binder 4 comprising: [0111] i. 25 grams of
Eternal EC6360--polyester acrylate; [0112] ii. 25 grams of Allnex,
EB8602--urethane acrylate; [0113] iii. 20 grams of tricyclodecane
dimethanol diacrylate; [0114] iv. 7 grams of trimethylolpropane
triacrylate; [0115] v. 10 grams of isobornyl acrylate; [0116] vi. 9
grams of 2-phenoxythyl acrylate; [0117] vii. 9 grams of hexanediol
diacrylate; and [0118] viii. 3 grams of BlueStar Silicon, Scla UV
RCA 170--silicon acrylate.
[0119] The resin was mixed with high speed agitation at room
temperature (74.degree. F.) with the addition of 1.3266 grams of
dispersing agent. The dispersing agent being BYK Disperbyk 2008--an
acrylic block-copolymer. Next 4.5 grams of amine synergist
(Sartomer CN 371) and 5.86 grams of photoinitiator were added with
high speed agitation until completely dissolved in the mixture. The
photoinitiator includes 4.5 grams of diphenyl ketone and 1.17 grams
of 1-hydroxy-cyclohexyl phenyl ketone.
[0120] Next, 20.21 grams of matting agent and the various amounts
of abrasion resistant particles were added to each mixture of
Examples 0-7. The matting agent includes the following: [0121] i.
10.29 grams of Arkema, Orgasol 3501 EX D NAT1--a polyamide 6/12;
[0122] ii. 3.03 grams of MicroPowder Fluo HT having a particle size
ranging from 2 .mu.m to 4 .mu.m; and [0123] iii. 6.89 grams of
Evonik Acematt 3600--silica.
[0124] The matting agent and abrasion resistance particles are
added slowly, the mixture is agitated for at least 10 minutes with
high speed agitation in accordance with the amounts set forth in
Examples 19-21 shown in Table 6. After the high speed agitation,
the resulting curable coating composition is discharged from the
mixer and applied to a substrate by roll coating to a thickness of
6 .mu.m. Once applied to the substrate, the curable coating
composition is cured by UV radiation, thereby forming the LG
coating layer of the floor covering.
TABLE-US-00011 TABLE 7 Ex. 18 Ex. 19 Binder 2 108 108 Amine
Synergist 4.50 4.50 Photoinitiator 5.86 5.86 Matting Agent 20.21
20.21 Dispersing Agent 1.3266 1.3266 Feldspar 10.8 10.8 Diamond (6
.mu.m-10 .mu.m).sup.9 0.0 5.4 Amount of Diamond 0% 3.7% Total 150.7
156.10 .sup.9Diamond particles having an average particle size of 8
.mu.m and a standard deviation of 1.7
[0125] The cured LG coating layers were then abraded with 100 grit
abrading paper with 30 passes. Each sample as analyzed for
percentage of gloss retention and .DELTA.b color change value. The
results are provided in Table 8.
TABLE-US-00012 TABLE 8 Gloss Retention % .DELTA.b Color Value Ex.
18 64 0.9 Ex. 19 96 1.7
Experiment 5
[0126] A fifth set of tests were run to compare different TD ratios
of coating matrix thickness to average size of diamond particles.
The coating matrix of Experiment 5 is in accordance with the
compositions described in the present invention. The fourth set of
tests further compares the different average particle spacing
T.sub.S between diamond particles within the coating layer. Each
coating layer was prepared according to the high agitation blending
previously discussed and applied to a substrate by roll coating.
The coating layer was then cured with UV radiation and abraded with
100 grit abrading paper with 30 passes. After abrading, each sample
was compared for retention of desired visual appearance--wherein
the rank of visual appearance was calculated on a scale of 0 to 1.
A value of 0 being the best having minimal abrasion, and a value of
1 being the worst having visually significant and noticeable
abrasions. The results are provided in Table 9.
TABLE-US-00013 TABLE 9 Ex. 20 Ex. 21 Ex. 22 Ex. 23 Ex. 24 Ex. 25
Ex. 26 Diamond (6 .mu.m-10 .mu.m).sup.10 3.7 wt. % 3.7 wt. % 3.7
wt. % 3.7 wt. % 3.7 wt. % 3.7 wt. % 3.7 wt. % Coating Matrix
Thickness 3.7 .mu.m 5.7 .mu.m 6.9 .mu.m 9.4 .mu.m 12.2 .mu.m 16.0
.mu.m 20.5 .mu.m TD Ratio of T.sub.CM:D.sub.AP 0.46:1 0.72:1 0.86:1
1.18:1 1.53:1 2:1 2.56:1 T.sub.s - Average Particle Separation
Distance 77 .mu.m 62 .mu.m 57 .mu.m 49 .mu.m 43 .mu.m 37 .mu.m
N/A.sup.11 Scratch Resistance and Gloss Retention 0.92 0.63 0.51
0.41 0.44 0.60 N/A.sup.12 .sup.10Diamond particles having an
average particle size of 8 .mu.m and a standard deviation of 1.7
.sup.11Using a TD ratio of 2.56:1 resulted in difficulty in
handling and applying the coating layer to the substrate by roll
coating .sup.12Using a TD ratio of 2.56:1 resulted in difficulty in
handling and applying the coating layer to the substrate by roll
coating
[0127] The coating layers produced using a TD ratio of average
coating matrix thickness to average particle size of the diamond
particles within the range of 0.6:1 to 2:1 resulted in a coating
layer exhibiting superior abrasion resistance and gloss retention
as well as provided sufficient operability in handling and applying
the coating layer to the substrate as compared to coating layers
produced using a TD ratio outside of the range of 0.6:1 to 2:1.
Experiment 6
[0128] A sixth set of tests were performed to demonstrate the
multi-layer coating layers for the flooring composition by
comparing different TD ratios of coating matrix thickness to
average size of diamond particles as well as the different average
particle spacing T.sub.S between diamond particles within the
coating layer. The coating matrix of Experiment 6 is in accordance
with the compositions described in the present invention. Each
example describes a single layer within the three-layered coating
layer. Each of the single coating layers were produced according to
the previously discussed master batch high agitation blending
process. The first layer was applied directly to the substrate by
roll coating and partially cured. The second and third subsequent
layers were applied in the same manner and each individually
partially cured before the subsequent layer was applied. The
results are provided in Table 10.
TABLE-US-00014 TABLE 10 Ex. 27 Ex. 28 Diamond (6 .mu.m-10
.mu.m).sup.13 3.7 wt. % 3.7 wt. % Coating Matrix Thickness 4.6
.mu.m 7.5 .mu.m TD Ratio of T.sub.CM:D.sub.AP 0.58:1 0.94:1 T.sub.S
- Average Particle Separation Distance 70 .mu.m 55 .mu.m Scratch
Resistance and Gloss Retention 0.27 0.14 .sup.13Diamond particles
having an average particle size of 8 .mu.m and a standard deviation
of 1.7
[0129] After fully curing the multi-layered coating layer, the top
surface of the coating layer was abraded with 100 grit sanding
paper using 30 passes with 2.1 pound weight applied. After
abrading, each sample was compared for retention of desired visual
appearance. After abrading, each sample was compared for retention
of desired visual appearance--wherein the rank of visual appearance
was calculated on a scale of 0 to 1. A value of 0 being the best
having minimal abrasion, and a value of 1 being the worst having
visually significant and noticeable abrasions.
[0130] As those skilled in the art will appreciate, numerous
changes and modifications may be made to the embodiments described
herein, without departing from the spirit of the invention. It is
intended that all such variations fall within the scope of the
invention.
* * * * *