U.S. patent application number 15/031082 was filed with the patent office on 2016-09-01 for carpet product and process for the manufacturing of a carpet product.
This patent application is currently assigned to WACKER CHEMICAL CORPORATION. The applicant listed for this patent is WACKER CHEMICAL CORPORATION. Invention is credited to JOHN M. MCCLURKEN, RONALD JOSEPH PANGRAZI, DENNIS SAGL.
Application Number | 20160251801 15/031082 |
Document ID | / |
Family ID | 51795844 |
Filed Date | 2016-09-01 |
United States Patent
Application |
20160251801 |
Kind Code |
A1 |
SAGL; DENNIS ; et
al. |
September 1, 2016 |
CARPET PRODUCT AND PROCESS FOR THE MANUFACTURING OF A CARPET
PRODUCT
Abstract
A carpet product includes in sequence a) a primary backing
material having a back side and a face side, with carpet fibers
extending from the face side to form a carpet pile and also passing
through the primary backing material and forming loops on the back
side; b) a primary coating layer on the loops, including a vinyl
acetate ethylene copolymer and present at from 542 to 1085
g/m.sup.2 (16 to 32 oz./yd.sup.2) on a dry solids basis; c) a
secondary coating layer on the primary coating layer, including a
styrene-butadiene copolymer; and d) a secondary backing material on
the secondary coating layer and adhered thereby to the primary
coating layer.
Inventors: |
SAGL; DENNIS; (FOGELSVILLE,
PA) ; PANGRAZI; RONALD JOSEPH; (FLEETWWOOD, PA)
; MCCLURKEN; JOHN M.; (DALTON, GA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
WACKER CHEMICAL CORPORATION |
ADRIAN |
MI |
US |
|
|
Assignee: |
WACKER CHEMICAL CORPORATION
ADRIAN
MI
|
Family ID: |
51795844 |
Appl. No.: |
15/031082 |
Filed: |
October 22, 2014 |
PCT Filed: |
October 22, 2014 |
PCT NO: |
PCT/US2014/061697 |
371 Date: |
April 21, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61895149 |
Oct 24, 2013 |
|
|
|
Current U.S.
Class: |
428/95 |
Current CPC
Class: |
D06N 2203/047 20130101;
D06N 2205/023 20130101; D06N 2209/103 20130101; D06N 2203/045
20130101; D06N 2203/042 20130101; D06N 2211/066 20130101; D06N
7/0081 20130101; D06N 2213/065 20130101; D06N 7/0073 20130101; D06N
2205/045 20130101 |
International
Class: |
D06N 7/00 20060101
D06N007/00 |
Claims
1. A carpet product comprising in sequence a) a primary backing
material having a back side and a face side, with carpet fibers
extending from the face side to form a carpet pile and also passing
through the primary backing material and forming loops on the back
side; b) a primary coating layer on the loops, comprising a vinyl
acetate ethylene copolymer as the only binder, wherein the vinyl
acetate ethylene copolymer comprises no comonomers other than vinyl
acetate and ethylene, and present at from 542 to 1085 g/m.sup.2 (16
to 32 oz./yd.sup.2) on a dry solids basis; c) a secondary coating
layer on the primary coating layer, comprising a styrene-butadiene
copolymer as the only binder; and d) a secondary backing material
on the secondary coating layer and adhered thereby to the primary
coating layer.
2. The carpet product of claim 1, wherein the vinyl acetate
ethylene copolymer comprises vinyl acetate units in an amount of 70
to 98 wt %, based on the total weight of comonomers.
3. The carpet product of claim 1, wherein the vinyl acetate
ethylene copolymer comprises vinyl acetate units in an amount of 75
to 95 wt %, based on the total weight of comonomers.
4. The carpet product of claim 1, wherein the vinyl acetate
ethylene copolymer comprises vinyl acetate units in an amount of 80
to 95 wt %, based on the total weight of comonomers.
5. The carpet product of claim 1, wherein the vinyl acetate
ethylene copolymer comprises ethylene in an amount of 2 to 30 wt %,
based on the total weight of comonomers.
6. The carpet product of claim 1, wherein the vinyl acetate
ethylene copolymer comprises ethylene in an amount of 5 to 15 wt %,
based on the total weight of comonomers.
7. The carpet product of claim 1, wherein the vinyl acetate
ethylene copolymer comprises ethylene in an amount of 10 to 12 wt
%, based on the total weight of comonomers.
8. The carpet product of claim 1, wherein the vinyl acetate
ethylene copolymer in the primary coating layer is derived from a
vinyl acetate ethylene copolymer dispersion stabilized only by one
or more emulsifiers and one or more protective colloids.
9. The carpet product of claim 1, wherein the vinyl acetate
ethylene copolymer in the primary coating layer is derived from a
vinyl acetate ethylene copolymer dispersion stabilized only by one
or more emulsifiers.
10. The carpet product of claim 1, wherein the vinyl acetate
ethylene copolymer in the primary coating layer is derived from a
vinyl acetate ethylene copolymer dispersion stabilized only by one
or more protective colloids.
11. The carpet product of claim 10, wherein the one or more
protective colloids consist of one or more polyvinyl alcohols.
12. The carpet product of claim 11, wherein the one or more
polyvinyl alcohols comprise at least one partially hydrolyzed
polyvinyl alcohol and at least one polyvinyl alcohol having a
degree of hydrolysis of 98 to 100 mol %.
13. The carpet product of claim 1, wherein the styrene butadiene
copolymer comprises 20 to 79.9 wt %, preferably 50 to 65 wt %
styrene and 20 to 79.9 wt %, preferably 35 to 50 wt % butadiene,
based on the total amount of comonomers.
14. The carpet product of claim 1, wherein the styrene butadiene
copolymer comprises 0.1 to 15 wt % in total of auxiliary
comonomers, based on the total weight of comonomers.
15. The carpet product of claim 14, wherein the auxiliary
comonomers are selected from the group consisting of ethylenically
unsaturated mono-carboxylic acids, ethylenically unsaturated
di-carboxylic acids, the anhydrides or salts of either of these,
and combinations of any of the foregoing.
16. A process for manufacturing the carpet product according to
claim 1, comprising in sequence a) providing a primary backing
material having a back side and a face side, with carpet fibers
extending from the face side to form a carpet pile and also passing
through the primary backing material and forming loops on the back
side; b) coating the loops with an aqueous primary coating
composition comprising a vinyl acetate ethylene copolymer as the
only binder, wherein the vinyl acetate ethylene copolymer comprises
no comonomers other than vinyl acetate and ethylene, to form a wet
primary coating layer providing from 542 to 1085 g/m.sup.2 (16 to
32 oz./yd.sup.2) of coating on a dry solids basis; c) coating a
secondary backing material with an aqueous secondary coating
composition comprising a styrene butadiene copolymer as the only
binder to form a wet secondary coating layer; d) pressing the
product of step c) against the product of step b) to contact the
wet primary coating layer with the wet secondary coating layer, and
e) drying the product of step d).
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority benefit of U.S. provisional
patent application No. 61/895,149, filed 24 Oct. 2013, the entirety
of which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a carpet product and a
process for manufacturing it.
BACKGROUND OF THE INVENTION
[0003] Carpets typically include a primary backing material to
which carpet fibers are attached to form a carpet pile on the face
side, and a primary coating layer on the back side of the primary
backing material to fix the carpet fibers to the primary backing.
To improve dimensional stability, a secondary backing material is
often fixed to the primary backing material by means of a secondary
coating layer.
[0004] The primary and secondary coating layers are typically
formed from aqueous polymer dispersions, for example aqueous vinyl
acetate ethylene copolymer dispersions and lattices of carboxylated
styrene butadiene copolymers.
[0005] U.S. Pat. No. 3,779,799 describes the use of an aqueous
latex of carboxylated styrene butadiene copolymers, or
alternatively of an aqueous dispersion of vinyl acetate ethylene
copolymer, as the primary coating for the tufted primary backing
material of carpets.
[0006] U.S. Pat. Nos. 4,735,986 and 5,084,503 describe carpet
backing adhesives employing vinyl acetate ethylene dispersions
stabilized with a mixture of polyvinyl alcohols. A high tuft lock
is said to be obtained with such dispersions. It is also mentioned
that such vinyl acetate ethylene dispersions are compatible with
most styrene butadiene emulsions. The use of different types of
coating materials for the primary and secondary coating layers is
not disclosed.
[0007] U.S. patent application 2001/0046581 discloses a carpet
comprising a primary backing with a yarn attached with an adhesive,
with a woven secondary backing attached to the back side of the
primary backing with the same adhesive. The second side of the
secondary backing is coated with a thermoplastic polymer layer by
melt bonding.
[0008] WO 2012/020321 A2 discloses carpet products with coating
layers formed from vinyl ester ethylene copolymer dispersions. The
vinyl ester ethylene copolymer dispersions have a particle size of
50 to 500 nm, and the dispersions are used to coat the primary
backing material as well as for laminating the secondary backing
material. Styrene-based emulsions are described as prior art
binders for coating compositions for carpet materials, but these
are said to be more expensive and have worse washability and are
not used in the invention.
[0009] U.S. patent application 2008/0113146 describes a method for
manufacturing carpets from recycled materials wherein EVA hotmelt,
vinyl acetate ethylene emulsion, carboxylated styrene butadiene
latex, styrene butadiene latex, acrylic latex, polyolefin hotmelt,
polyolefin dispersion, or butadiene acrylate copolymers are
described as adhesive backing materials for coating the primary
backing materials.
[0010] WO 2010/129945 discloses a method for manufacturing carpets
from recycled materials, using filler obtained from recycling of
waste carpets. EVA hotmelt, vinyl acetate ethylene emulsion,
carboxylated styrene butadiene latex, styrene butadiene latex,
acrylic latex, polyolefin hotmelt, polyolefin dispersion, or
butadiene acrylate copolymers are described as coating agents for
coating the primary backing materials.
[0011] U.S. patent application 2013/0209726 describes a latex
coating composition comprising a blend of a vinyl ester ethylene
copolymer and a styrene butadiene copolymer. The blend may be used
as a precoat binder, a skipcoat binder, or both.
[0012] Japanese parent application JP 59-214633 discloses coating a
polypropylene woven fabric coated with an ethylenic copolymer
emulsion, e.g., a vinyl acetate ethylene copolymer emulsion (VAE),
followed by drying. Pile yarns are then interwoven with the dry
VAE-coated base fabric. A styrene butadiene rubber latex (SBR) is
then applied to the dried VAE layer and the loops of pile yarn
emerging from it. Then, a secondary base fabric of expanded
polypropylene woven cloth bearing a wet coating of an ethylenic
copolymer emulsion, e.g., a VAE, is laid upon the wet SBR latex
coating with the VAE and SBR coatings in contact, and bonded by
heating and drying the VAE emulsion and SBR latex. In some
embodiments, the VAE emulsion on the secondary base fabric is
omitted.
[0013] Despite these advances, improved methods and materials would
be beneficial for providing carpet having high tuft lock and high
delamination resistance, yet easily processable at the elevated
temperatures encountered on carpet coating lines.
SUMMARY OF THE INVENTION
[0014] In one aspect, the invention provides a carpet product
including in sequence
[0015] a) a primary backing material having a back side and a face
side, with carpet fibers extending from the face side to form a
carpet pile and also passing through the primary backing material
and forming loops on the back side;
[0016] b) a primary coating layer on the loops, including a vinyl
acetate ethylene copolymer and present at from 542 to 1085
g/m.sup.2 (16 to 32 oz./yd.sup.2) on a dry solids basis;
[0017] c) a secondary coating layer on the primary coating layer,
including a styrene-butadiene copolymer; and
[0018] d) a secondary backing material on the secondary coating
layer and adhered thereby to the primary coating layer.
[0019] In another aspect, the invention provides a process for
making a carpet product, including in sequence
[0020] a) providing a primary backing material having a back side
and a face side, with carpet fibers extending from the face side to
form a carpet pile and also passing through the primary backing
material and forming loops on the back side;
[0021] b) coating the loops with an aqueous primary coating
composition including a vinyl acetate ethylene copolymer to form a
wet primary coating layer providing from 542 to 1085 g/m.sup.2 (16
to 32 oz./yd.sup.2) of coating on a dry solids basis;
[0022] c) coating a secondary backing material with an aqueous
secondary coating composition including a styrene butadiene
copolymer to form a wet secondary coating layer;
[0023] d) pressing the product of step c) against the product of
step b) to contact the wet primary coating layer with the wet
secondary coating layer; and
[0024] e) drying the product of step d).
DETAILED DESCRIPTION OF THE INVENTION
[0025] Surprisingly, the inventors have found that a specific
combination of primary coating layer and secondary coating layer
makes possible the production of carpet having high tuft lock and
high delamination resistance, yet easily processable at the
elevated temperatures encountered on carpet coating lines.
Structural Carpet Components
[0026] The primary backing material typically comprises any
material recognized in the art for use as a carpet backing.
Specific examples typically include woven or nonwoven fabrics made
from one or more of natural or synthetic fibers or yarns including
jute, wool, polypropylene, polyethylene, polyimide, polyesters,
rayon, or various copolymers.
[0027] The primary backing has a face side and a back side. Carpet
fibers (yarn) are attached to the primary backing, extending from
the face side to form the carpet face. The fibers can be made with
uncut yarn loops, cut yarn loops (a pile of single yarns), or a
combination of cut and uncut yarns. The fibers can be made from
wool, cotton, nylon, acrylic resin, polyester, polypropylene and
blends thereof. As the fiber material is not critical, other fiber
material would be readily apparent to one of skill in the art,
i.e., any material recognized in the art for use as a carpet fiber.
A tufting method can be used to fix fibers to the primary backing
material. In a typical case, carpet fibers extend from the face
side to form a carpet pile and pass through the primary backing
material to form loops on the back side. Typically, the primary
backing will have a basis weight in a range from 102 to 339
g/m.sup.2 (3 to 10 oz./yd.sup.2), more typically in a range from
136 to 237 g/m.sup.2 (4 to 7 oz./yd.sup.2). The combination of
primary backing and carpet fibers (yarn) will typically have a
basis weight in a range from 339 to 1017 g/m.sup.2 (10 to 30
oz./yd.sup.2).
[0028] The secondary backing side is oriented toward and attached
to the back side of the primary backing, with the primary and
secondary coating layers interposed. The secondary backing can be
made of a variety of materials. Typically, it will be made of one
or more of the materials mentioned above for making the primary
backing. In most cases the secondary backing will not have carpet
pile fibers passing through it, and will not have carpet pile
fibers directly adhered or otherwise directly attached to it. Here
the term "directly" means without any intervening woven or nonwoven
fabric layer(s). Typically, the secondary backing will have a basis
weight in a range from 33.9 to 203 g/m.sup.2 (1 to 6 oz./yd.sup.2).
More typically, the range will be in a range from 102 to 170
g/m.sup.2 (3 to 5 oz./yd.sup.2).
[0029] The primary coating layer will typically be present at a
loading level in a range from 542 to 1085 g/m.sup.2 (16 to 32
oz./yd.sup.2) on a dry solids basis. More typically, the amount
will be in a range from 610 to 881 g/m.sup.2 (18 to 26
oz./yd.sup.2). The secondary coating layer will typically be
present at a loading level in a range from 203 to 305 g/m.sup.2 (6
to 9 oz./yd.sup.2) on a dry solids basis. More typically, the
amount will be in a range from 237 to 271 g/m.sup.2 (7 to 8
oz./yd.sup.2).
[0030] Generally, the primary backing material, the secondary
backing material, the primary coating layer and the secondary
coating layer are each independently coextensive with one or more
of the others. Most typically, they are all mutually
coextensive.
Vinyl Acetate Ethylene Copolymer Dispersion
[0031] The vinyl acetate ethylene copolymer comprises vinyl acetate
units in an amount of 70 to 98 wt %, based on the total weight of
comonomers. Preferably the vinyl acetate content is in the range of
75 to 95 wt %, most preferred the vinyl acetate content is in the
range of 80 to 95 wt %, in each case based on the total weight of
comonomers.
[0032] The copolymer comprises ethylene in an amount of 2 to 30 wt
%, based on the total weight of comonomers. The amount is
preferably 5 to 15 wt %, most preferred 10 to 12 wt %, in each case
based on the total weight of comonomers.
[0033] Most preferred copolymers are those of ethylene and vinyl
acetate without further comonomers. Nonetheless, in some
embodiments the copolymer may include up to 30 wt %, preferably up
to 10 wt %, in each case based on the total weight of comonomers,
of other non-functional monomer units selected from the group
consisting of vinyl chloride, (meth)acrylic acid esters and vinyl
esters other than vinyl acetate. Suitable other vinyl esters are
those of carboxylic acids with 3 to 12 carbon atoms such as vinyl
propionate, vinyl butyrate, vinyl 2-ethylhexanoate, vinyl laurate,
1-methyl vinyl acetate, vinyl pivalate and vinyl esters of
.alpha.-branched monocarboxylic acids with 9 to 11 carbon atoms,
such as VeoVa.TM.9R, VeoVa.TM.10R, or VeoVa.TM.11R (available from
Hexion Specialty Chemicals, Inc., Columbus, Ohio). Suitable
methacrylic or acrylic acid esters are esters of straight-chain or
branched alcohols having 1 to 15 carbon atoms, for example methyl
acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate,
propyl acrylate, propyl methacrylate, butyl acrylate (n-, iso- and
tert-), n-butyl methacrylate, 2-ethylhexyl acrylate and norbornyl
acrylate. Methyl acrylate, methyl methacrylate, butyl acrylate and
2-ethylhexyl acrylate are preferred. Such non-functional monomers
may be introduced for example to adjust glass transition
temperature or hydrophobicity.
[0034] In some embodiments, auxiliary monomers (functional
monomers) may be copolymerized in an amount up to 10 wt %,
preferably 0.05 to 10 wt %, most preferred 0.1 to 2 wt %, in each
case based on the total weight of comonomers. Examples of auxiliary
monomers are ethylenically unsaturated monocarboxylic and
dicarboxylic acids, typically acrylic acid, methacrylic acid,
fumaric acid and maleic acid; ethylenically unsaturated
carboxamides and carbonitriles, typically acrylamide and
acrylonitrile; monoesters and diesters of fumaric acid and maleic
acid, such as the diethyl and diisopropyl esters, and also maleic
anhydride, ethylenically unsaturated sulphonic acids and their
salts, typically vinylsulphonic acid,
2-acrylamido-2-methylpropanesulphonic acid. Such auxiliary monomers
may for example improve dispersion stability.
[0035] Further examples of such auxiliary monomers are
crosslink-forming functional comonomers. Examples for
precrosslinking comonomers are polyethylenically unsaturated
comonomers, examples being divinyl adipate, diallyl maleate, allyl
methacrylate or triallyl cyanurate. Examples of postcrosslinking
comonomers are acrylamidoglycolic acid (AGA),
methylacrylamidoglycolic acid methyl ester (MAGME),
N-methylolacrylamide (NMA), N-methylolmethacrylamide (NMMA),
N-methylolallylcarbamate, alkyl ethers such as the isobutoxy ether
or esters of N-methylolacrylamide or of N-methylolmethacrylamide or
of N-methylolallylcarbamate.
[0036] Also suitable as auxiliary monomers are ethylenically
unsaturated, hydrolyzable silicon compounds. For example compounds
of the general formula R.sup.1SiR.sub.0-2(OR.sup.2).sub.1-3, where
R has the definition C.sub.1 to C.sub.3 alkyl radical, C.sub.1 to
C.sub.3 alkoxy radical or halogen (e.g., Cl or Br), R.sup.1 has the
definition CH.sub.2.dbd.CR.sub.3--(CH.sub.2).sub.0-1 or
CH.sub.2.dbd.CR.sup.3CO.sub.2(CH.sub.2).sub.1-3, R.sup.2 is
unbranched or branched, optionally substituted alkyl radical or
acyl radical having 1 to 12 C atoms, which may optionally be
interrupted by an ether group, and R.sup.3 stands for H or
CH.sub.3. Preference is given to .gamma.-acryloyl- and
.gamma.-methacryloyl-oxypropyltri(alkoxy)silanes,
vinylalkyldialkoxysilanes, and vinyltrialkoxysilanes, having
C.sub.1 to C.sub.12 alkoxy groups and optionally C.sub.1 to C.sub.3
alkyl radicals, and also .alpha.-silanes, with examples of C.sub.1
to C.sub.12 alkoxy groups that can be used being methoxy, ethoxy,
methoxyethylene, ethoxyethylene, methoxypropylene glycol ether
and/or ethoxypropylene glycol ether radicals. Ethylenically
unsaturated, hydrolyzable silicon compounds that are most preferred
are vinyltrimethoxysilane, vinyltriethoxysilane,
3-methacryloyloxypropyltrimethoxysilane,
3-methacryloyloxypropyltriethoxysilane,
.alpha.-methacryloyloxymethyltriethoxysilane.
[0037] Further examples for auxiliary monomers are ethylenically
unsaturated compounds containing epoxide groups, such as, for
example, glycidyl methacrylate, glycidyl acrylate, allyl glycidyl
ether, vinyl glycidyl ether, vinylcyclohexane oxide, limonene
oxide, myrcene oxide, caryophyllene oxide, and styrenes and
vinyltoluenes substituted by a glycidyl radical on the aromatic
moiety, and also vinyl benzoates substituted by glycidyl radicals
on the aromatic moiety. Preference is given to glycidyl acrylate,
glycidyl methacrylate, allyl glycidyl ether, and vinyl glycidyl
ether.
[0038] While some applications may favor the inclusion of
additional monomers in the VAE copolymer, for example such as those
listed above, it may nonetheless in some cases be advantageous to
exclude certain monomers, depending on the specific needs of a
given application. In other cases, these monomers may be included
up to a limit of 1.0 wt % of the VAE copolymer. The excluded or
limited monomers may include any one or more of the following:
i-butoxy methylacrylamide; acrylamidoglycolic acid;
acrylamidobutyraldehyde; dialkyl acetals of
acrylamidobutyraldehyde; glycidyl-containing compounds (e.g.,
glycidyl (meth)acrylate, triglycidyl isocyanurate, etc.);
ethylenically unsaturated phosphates, phosphonates or sulfates;
ethylenically unsaturated silicon compounds; (meth)acrylamide or
N-substituted (meth)acrylamides; (meth)acrylic esters; vinyl
ethers; acrylonitrile; butadiene; styrene; vinyltoluene; divinyl
benzene and/or other olefinically unsaturated hydrocarbons other
than ethylene; halogenated monomers (e.g., vinyl chloride); and
esters of allyl alcohol. In some embodiments of the invention, only
VAE copolymers not containing further comonomer units or auxiliary
monomers are used.
[0039] In each case the data in % by weight are based on the total
weight of comonomers and summing up to 100% by weight.
[0040] The monomers are preferably selected so as to give
copolymers with a glass transition temperature Tg of -30.degree. C.
to +30.degree. C., preferably -5.degree. C. to 20.degree. C., and
most preferred 0.degree. C. to 18.degree. C. The glass transition
temperature Tg of the copolymers may be determined in a known
manner by means of differential scanning calorimetry (DSC)
according to ASTM D3418-03.
[0041] The Tg may also be calculated approximately in advance by
means of the Fox equation. According to Fox T. G., Bull. Am.
Physics Soc. 1, 3, page 123 (1956), it holds that:
1/Tg=x.sub.1/Tg.sub.1+x.sub.2/Tg.sub.2+ . . . +x.sub.n/Tg.sub.n,
where x.sub.n is the mass fraction (wt %/100) of the monomer n and
Tg.sub.n is the glass transition temperature, in kelvins, of the
homopolymer of the monomer n. Tg values for homopolymers are listed
in the Polymer Handbook, 2nd Edition, J. Wiley & Sons, New York
(1975).
[0042] The vinyl acetate ethylene copolymer can be prepared by an
aqueous emulsion polymerization using conventional emulsion
polymerization procedure. Preferably at a temperature in a range
from 40.degree. C. to 150.degree. C., more preferred 50.degree. C.
to 120.degree. C. and most preferred 60.degree. C. to 100.degree.
C. The polymerization pressure is generally between 40 and 100 bar
absolute, preferably between 45 and 90 bar absolute, and most
preferred between 45 and 85 bar absolute, depending on the ethylene
feed.
[0043] Polymerization may be initiated using a redox initiator
combination such as is customary for an aqueous emulsion
polymerization. Examples of suitable oxidation initiators are
hydrogen peroxide, tert-butyl peroxide, tert-butyl hydroperoxide,
potassium peroxodiphosphate, tert-butyl peroxopivalate, cumene
hydroperoxide, isopropylbenzene monohydroperoxide,
azobisisobutyronitrile, and the sodium, potassium, and ammonium
salts of peroxodisulfuric acid. Preference is given to the sodium,
potassium, and ammonium salts of peroxodisulfuric acid and to
hydrogen peroxide. The stated initiators are used in general in an
amount of 0.01 wt % to 2.0 wt %, based on the total weight of the
comonomers.
[0044] The stated oxidizing agents, more particularly hydrogen
peroxide or the salts of peroxodisulfuric acid, may also be used on
their own as thermal initiators.
[0045] Suitable reducing agents are ammonium or alkali metal
sulfites and bisulfites, as for example sodium sulfite, the
derivatives of sulfoxylic acid such as zinc sulfoxylates or alkali
metal formaldehyde sulfoxylates, such as sodium
hydroxymethanesulfinate (Bruggolit). It is preferred to use a
non-formaldehyde generating redox initiation system. In general,
suitable non-formaldehyde generating reducing agents for redox
pairs include, as non-limiting examples, those based on ascorbic
acid or its salts, or erythorbate (iso-ascorbic acid) or its salts,
or tartaric acid or its salts, or bisulfite salts particularly
sodium bisulfite, as known in the art, or disodium glycolic acid
sulfonate hydrate, which is available as a commercial reducing
agent known as BRUGGOLITE.RTM. FF6M manufactured by Brueggeman
Chemical of Heilbronn, Germany. It is preferred to use disodium
glycolic acid sulfonate hydrate, or sodium sulfite, or ascorbic
acid or its salts, or erythorbic acid (iso-ascorbic acid) or its
salts. The amount of reducing agent is preferably 0.01 wt % to 3 wt
%, based on the total weight of the comonomers.
[0046] Regulating substances may be used during the polymerization
to control the molecular weight of the copolymer. In a preferred
embodiment no regulating substances are used. If regulators are
used, they are employed typically in amounts between 0.01 wt % to
5.0 wt %, based on the total weight of the monomers to be
polymerized, and are metered separately or else as a premix with
reaction components. Examples of such substances are n-dodecyl
mercaptan, tert-dodecyl mercaptan, mercaptopropionic acid, methyl
mercaptopropionate, isopropanol, and acetaldehyde.
[0047] One or more emulsifiers and/or one or more protective
colloids are used to stabilize the aqueous dispersion of the vinyl
acetate ethylene copolymers.
[0048] Suitable emulsifiers are nonionic, anionic or cationic
emulsifiers. Preferably nonionic or anionic emulsifiers are used,
or mixtures of nonionic and anionic emulsifiers. The amount of
emulsifier is preferably 0.5 to 10 wt %, more preferably 1 to 5 wt
%, in each case based on the total amount of comonomers.
[0049] Suitable nonionic emulsifiers are, for example, acyl, alkyl,
and oleyl ethoxylates. These products are available commercially,
for example, under the name GENAPOL.RTM. or LUTENSOL.RTM.. Suitable
nonionic emulsifiers also include ethoxylated branched or
unbranched fatty alcohols (aliphatic alcohols), preferably having a
degree of ethoxylation of 3 to 80 ethylene oxide units and C.sub.6
to C.sub.36 alkyl radicals. Other suitable nonionic emulsifiers
include C.sub.13-C.sub.15 oxo-process alcohol ethoxylates having a
degree of ethoxylation of 3 to 30 ethylene oxide units,
C.sub.16-C.sub.18 fatty alcohol ethoxylates having a degree of
ethoxylation of 11 to 80 ethylene oxide units, C.sub.10 oxo-process
alcohol ethoxylates having a degree of ethoxylation of 3 to 11
ethylene oxide units, C.sub.13 oxo-process alcohol ethoxylates
having a degree of ethoxylation of 3 to 20 ethylene oxide units,
polyoxyethylenesorbitan monooleate having 20 ethylene oxide groups,
copolymers of ethylene oxide and propylene oxide with a minimum
content of at least 10 wt % of ethylene oxide, and polyethylene
oxide ethers of oleyl alcohol having a degree of ethoxylation of 4
to 20 ethylene oxide units.
[0050] Preferred are ethoxylated branched or unbranched aliphatic
alcohols, particularly having a degree of ethoxylation of 3 to 80
ethylene oxide units and C.sub.8 to C.sub.36 alkyl radicals.
Preferred nonionic emulsifiers are also C.sub.13-C.sub.15
oxo-process alcohol ethoxylates having a degree of ethoxylation of
3 to 30 ethylene oxide units, and C.sub.16-C.sub.18 aliphatic
alcohol ethoxylates having a degree of ethoxylation of 11 to 80
ethylene oxide units. Particularly preferred are C.sub.12-C.sub.14
aliphatic alcohol ethoxylates having a degree of ethoxylation of 3
to 20 ethylene oxide units. Preferably the copolymer dispersion is
free of alkylphenol ethoxylates and esters thereof.
[0051] Examples of suitable anionic emulsifiers are sodium,
potassium, and ammonium salts of straight-chain aliphatic
carboxylic acids having 12 to 20 C atoms; sodium
hydroxyoctadecanesulfonate; sodium, potassium, and ammonium salts
of hydroxyl-fatty acids having 12 to 20 C atoms and the sulfonation
and/or acetylation products thereof; sodium, potassium, and
ammonium salts of alkyl sulfates, also as triethanolamine salts,
and sodium, potassium, and ammonium salts of alkylsulfonates having
in each case 10 to 20 C atoms and of alkylarylsulfonates having 12
to 20 C atoms; dimethyldialkylammonium chlorides having 8 to 18 C
atoms and its sulfonation products; sodium, potassium, and ammonium
salts of sulfosuccinic esters with aliphatic saturated monohydric
alcohols having 4 to 16 C atoms, and sulfosuccinic 4-esters with
polyethylene glycol ethers of monohydric aliphatic alcohols having
10 to 12 C atoms, more particularly their disodium salts, and of
biscyclohexyl sulfosuccinate, more particularly its sodium salt;
ligninsulfonic acid and also its calcium, magnesium, sodium, and
ammonium salts; and resin acids or hydrogenated or dehydrogenated
resin acids, and alkali metal salts of any of these.
[0052] The most preferred anionic emulsifiers are the sodium,
potassium, and ammonium salts of alkyl sulfates and of
alkylsulfonates having in each case 10 to 20 C atoms, and also of
alkylarylsulfonates having 12 to 20 C atoms, and of sulfosuccinic
esters with aliphatic saturated monohydric alcohols having 4 to 16
C atoms.
[0053] Suitable protective colloids include polyvinyl alcohols;
polyvinyl acetals; polyvinylpyrrolidones; polysaccharides in
water-soluble form such as starches (amylase and amylopectin),
celluloses and their carboxymethyl, methyl, hydroxyethyl,
hydroxypropyl derivatives; proteins such as casein or caseinate,
soya protein, gelatine; lignosulfonates, synthetic polymers such as
poly(meth)acrylic acid, copolymers of (meth)acrylates with
carboxyl-functional comonomer units, poly(meth)-acrylamide,
polyvinylsulfonic acids, and the water-soluble copolymers thereof;
melamine-formaldehyde sulfonates, naphthalene-formaldehyde
sulfonates, styrene-maleic acid copolymers, and vinyl ether-maleic
acid copolymers.
[0054] Preference is given to using partially hydrolyzed (degree of
hydrolysis: 80 to 95 mol %) and/or fully hydrolyzed (degree of
hydrolysis: 98 to 100 mol %) polyvinyl alcohols. Preferred
partially hydrolyzed polyvinyl alcohols have a degree of hydrolysis
of 80 to 95 mol % and a Hoppler viscosity, in 4% strength aqueous
solution, of 1 to 30 mPas (method of Hoppler at 20.degree. C., DIN
53015). Most preferred are polyvinyl alcohols having a degree of
hydrolysis of 85 to 94 mol % and a Hoppler viscosity, in 4%
strength aqueous solution, of 3 to 25 mPas (method of Hoppler at
20.degree. C., DIN 53015). As used herein, the "degree of
hydrolysis" of a polyvinyl alcohol means the degree to which vinyl
acetate monomer units have been hydrolyzed to alcohols.
[0055] Other preferred embodiments employ a mixture of one or more
partially hydrolyzed polyvinyl alcohol(s) and one or more fully
hydrolyzed polyvinyl alcohol(s). Preferred fully hydrolyzed
polyvinyl alcohols have a degree of hydrolysis of 98 to 99.95 mol %
and a Hoeppler viscosity of 13 to 30 mPas (method of Hoppler at
20.degree. C., DIN 53015).
[0056] Both partially hydrolyzed and fully hydrolyzed polyvinyl
alcohols may be hydrophobically modified, e.g., they may comprise
hydrophobic comonomers, one example of which is ethylene.
[0057] The total amount of the protective colloid is preferably 1
to 5 wt %, based on the total weight of comonomers.
[0058] It is also a preferred embodiment to use a mixture of at
least one emulsifier and at least one protective colloid.
[0059] The emulsifiers and protective colloids discussed above are
all commercially available or obtainable by processes known to the
skilled person.
Preparation of Aqueous Vinyl Acetate Ethylene Copolymer
Dispersions
[0060] In preparing the aqueous vinyl acetate ethylene copolymer
dispersion, all of the protective colloid or all of the emulsifier
may form an initial charge, or all of the protective colloid or all
of the emulsifier may form a feed, or portions of the protective
colloid or of the emulsifier may form an initial charge and the
remainder may form a feed after the polymerization has been
initiated. The feeds may be separate (spatially and
chronologically), or all or some of the components may be fed after
pre-emulsification. In a preferred embodiment all of the protective
colloid and optionally all of the emulsifier are charged initially
to the reactor.
[0061] All of the monomers may form an initial charge, or all of
the monomers may form a feed, or portions of the monomers may form
an initial charge and the remainder may form a feed after the
polymerization has been initiated. The feeds may be separate
(spatially and chronologically), or all or some of the components
may be fed after pre-emulsification. In a preferred embodiment at
least a part of the monomers, preferably 70 to 85 wt %, is added in
the initial charge.
[0062] Once the polymerization process has ended,
post-polymerization may be carried out using known methods to
remove residual monomer, for example using post-polymerization
initiated by a redox catalyst. Volatile residual monomers may also
be removed by distillation, preferably at subatmospheric pressure,
and, where appropriate, by passing inert entraining gases, such as
air, nitrogen, or water vapor, through or over the material.
[0063] The solids content of suitable aqueous vinyl acetate
ethylene copolymer dispersions is typically in a range from 45 wt %
to 75 wt %. The particle size distribution may be monomodal or
multimodal, and the mean particle diameter may range in size from
0.15 .mu.m to 10 .mu.m as measured by laser diffraction.
Styrene Butadiene Dispersions
[0064] The styrene butadiene copolymers comprise 20 to 79.9 wt %,
preferably 50 to 65 wt % styrene and 20 to 79.9 wt %, preferably 35
to 50 wt % butadiene, based on the total amount of comonomers.
Optionally 0.1 to 15 wt % of further auxiliary comonomers may be
present, in each case based on the total weight of comonomers.
Preferred auxiliary comonomers are ethylenically unsaturated
mono-carboxylic acids, and/or di-carboxylic acids, their
anhydrides, and their salts, and mixtures thereof, particularly
acrylic acid, methacrylic acid, itaconic acid and/or maleic acid
and/or fumaric acid.
[0065] Additional suitable auxiliary comonomers are for example,
alkyl esters of (meth)acrylic acid, such as, for example, methyl
methacrylate, ethylenically unsaturated carboxamides and
carbonitriles, such as, for example, (meth)acrylonitrile; diesters
of fumaric acid or maleic acid; hydroxy alkyl (meth)acrylates;
sulfur acid monomers, phosphorus acid monomers, crosslinking
comonomers, such as, for example, divinyl benzene or divinyl
adipates; postcrosslinking comonomers, such as acrylamidoglycolic
acid (AGA), allyl methacrylates or allyl N-methylol carbamates;
epoxy-functional comonomers, such as glycidyl (meth)acrylates; and
silicon-functional comonomers, such as alkoxysilane containing
(meth)acrylates or vinyl monomers.
[0066] While some applications may favor the inclusion of
additional monomers in the styrene butadiene copolymer, for example
such as those listed above, it may nonetheless in some cases be
advantageous to exclude certain monomers, depending on the specific
needs of a given application. In other cases, these monomers may be
included up to a limit of 1.0 wt % of the styrene butadiene
copolymer. Monomers that may be excluded or limited include those
mentioned above in this context with respect to the VAE
copolymer.
[0067] The styrene butadiene copolymers can be prepared by aqueous
emulsion or suspension polymerization, preferably emulsion
polymerization, in conventional manner, employing conventional
polymerization temperatures, preferably from 40.degree. C. to
120.degree. C., and pressures, preferably with diene comonomer
pressures up to 10 bar absolute.
[0068] The polymerization may be initiated using conventional
amounts of one or more conventional water-soluble initiators such
as sodium persulphate, or oil (monomer) soluble initiator, such as
tert-butyl peroxide and cumene hydroperoxide, or a redox initiator
combination, using a reducing agent such as sulfites and
bisulfites. To control the molecular weight, conventional regulator
substances or chain transfer agents, such as mercaptans, alkanols,
and dimeric alpha methylstyrene can be used during the
polymerization in conventional manner in conventional amounts of
from 0.01 to 5.0 percent by weight, or, preferably, up to 3 percent
by weight, based on the comonomers to be polymerized. The
polymerization process preferably takes place in known manner in
the presence of conventional amounts of one or more conventional
emulsifier and/or protective colloid. Suitable emulsifiers and
protective colloids are the same as described for preparing the
vinyl acetate ethylene dispersion.
[0069] The solids content of the styrene butadiene copolymer
dispersion is typically in a range from 45 wt % to 75 wt %.
Coating Compositions
[0070] To obtain the primary or secondary coating composition, the
vinyl acetate ethylene copolymer dispersion or the styrene
butadiene copolymer dispersion is combined with one or more fillers
and one or more thickeners, and optionally further additives.
[0071] Any filler suitable for use in carpet manufacture may be
used. Examples include mineral fillers or pigments including those
known in the art, such as calcium carbonate, ground glass, clay,
kaolin, talc, barites, feldspar, titanium dioxide, calcium aluminum
pigments, satin white, synthetic polymer pigment, zinc oxide,
barium sulphate, gypsum, silica, alumina trihydrate, mica, hollow
polymer pigments, and diatomaceous earth. Mixtures of fillers can
also be employed.
[0072] The amount of filler in the composition can vary depending
upon the density of the filler and the coating properties desired.
Typically, it will be from about 50 to about 800 dry weight parts
filler, more typically from about 100 to about 600 dry weight
parts, and most typically from about 250 to about 600 dry weight
parts, in each case per 100 dry weight parts of copolymer
solids.
[0073] One or more polymeric thickeners is typically included in
the composition to provide sufficient viscosity for application
according to conventional methods. Any polymeric thickener known in
the carpet coating art may be used, for example hydroxyethyl
cellulose and sodium polyacrylate. Although any amount of polymeric
thickener may be used, the inventors have found that typically no
more than 6 wt % of thickener is needed, relative to the amount of
aqueous dispersion of the copolymer, and thus in some embodiments
of the invention no more than 6 wt % is used, relative to the
amount of aqueous dispersion of the copolymer. In some embodiments,
at most 5 wt % or at most 4 wt % is used, relative to the amount of
aqueous dispersion of the copolymer. Typically, at least 1 wt % of
thickener, or at least 2 wt %, is used, relative to the amount of
aqueous dispersion of the copolymer.
[0074] The Brookfield RV viscosity of the resulting coating
composition should be in a range from 7000 to 15000 mPas, measured
with a Brookfield RV viscometer using spindle No. 5 at 25.degree.
C. and 20 rpm.
[0075] Further conventional additives in carpet coating
compositions are flame retardants or biocides or antioxidants. If a
foamed coating is desired blowing agents can be added to the
coating compositions.
Making the Carpet Product
[0076] The primary and secondary aqueous coating compositions can
be applied in various ways. For example the coating compositions
can be applied directly, such as with a roll over roll applicator,
or with a doctor blade. Alternatively, they can be applied
indirectly, such as with a pan applicator. Preferably a roll over
roller applicator is used. The primary coating coats at least the
loops on the back side of the primary backing, and may also coat
some or all of the back side of the backing itself.
[0077] The primary and secondary backing materials are brought
together to bring the still-wet primary and secondary coating
compositions into contact, typically with application of pressure,
and heat is then applied to evaporate the water from the coatings.
This may be done by passing the product through an oven, typically
set at a temperature between about 100.degree. C. and 150.degree.
C. Upon cooling, the final product is obtained.
[0078] A significant advantage of carpet products obtained
according to the invention is better delamination resistance
compared with carpet products according to the state of the
art.
EXAMPLES
[0079] The following polymer dispersions were used to prepare the
carpet products. Vinyl acetate-ethylene copolymer dispersion
(VAE):
[0080] An aqueous dispersion of a vinyl acetate ethylene copolymer
with a solids content of about 60 wt % was used. The dispersion was
costabilized with a protective colloid and a non-ionic surfactant.
The copolymer composition was about 85 wt % vinyl acetate and about
15 wt % ethylene, with a glass transition temperature Tg of about
2.degree. C.
Styrene Butadiene Copolymer Dispersion (SBR):
[0081] An aqueous dispersion of a styrene butadiene copolymer with
a solids content of about 55 wt % was used. The dispersion was
stabilized with an anionic surfactant. The copolymer composition
was about 65 wt % of styrene and about 35 wt % of butadiene, with a
glass transition temperature Tg of about 11.degree. C.
Carpet Coating Compositions:
Filler:
[0082] Filler used was calcium carbonate (CARMEUSE.TM. MW 101
manufactured by Carmeuse Lime and Stone, Chatsworth, Ga.).
Froth Aid:
[0083] Froth aid used was ammonium lauryl sulphate (STANFAX.RTM.
238 manufactured by Royal Adhesives, Dalton, Ga.).
Thickener:
[0084] Thickener used was a sodium polyacrylate (PARAGUM.RTM. 277
manufactured by Royal Adhesives, Dalton, Ga.).
General Recipe for the Carpet Coating Compositions Used as Primary
Coating Composition or Secondary Coating Composition in
Testing:
TABLE-US-00001 [0085] Material Dry weight [grams] Dispersion 100
Filler 450 Froth Aid 0.33 Thickener * Water * * Thickener and water
were admixed in amounts needed to obtain a carpet coating
composition having a total solids content of about 81.5 wt % and a
Brookfield viscosity (spindle No. 5, 20 rpm) of 6000 to 7000
cps.
[0086] The Uncoated Backing Materials Used in the Test were:
[0087] A nylon carpet greige goods (i.e., a backing with pile yarn
tufted in but without a binder) with a 678 g/m.sup.2 (20
oz./yd.sup.2) fate weight level loop nylon with a straight stitch
commercial style tufting construction was used as primary
backing.
[0088] A polypropylene 5 pick woven material with an average weight
of 68 g/m.sup.2 (2 oz./yd.sup.2) was used as secondary backing.
Preparation of Samples for Testing:
[0089] The primary and secondary coating compositions were admixed
according to the general recipe with a Lighting mixer. Thickener
and water were admixed in an amount necessary for obtaining a total
solids content of about 81.5 wt % and a Brookfield viscosity
(spindle No. 5, 20 rpm) of 6000 to 7000 cps.
[0090] The primary coating composition was applied with a spatula
having a 25.4 cm (10 in) blade to the backside of the nylon carpet
material at a rate of 949 g/m.sup.2 (28 oz./yd.sup.2) of primary
coating solids.
[0091] The secondary backing was coated with the secondary coating
composition with a draw-down bar at a 762 .mu.m (30 mil) wet film
thickness, resulting in about 237 g/m.sup.2 (7 oz./yd.sup.2) of
secondary coating solids. The wet coated secondary backing was
pressed against the wet coating layer on the primary backing with a
large stainless steel roller. The assembly was dried at 132.degree.
C. (270.degree. F.) in a convection air oven for 20 minutes, and
the resulting carpet product was allowed to stand at ambient
temperature and humidity for at least two hours before testing.
Test Methods
Determination of Tg According to ASTM D3418-03:
[0092] Glass transition temperatures of copolymers were measured
calorimetrically using a TA instruments Q20-1002 differential
scanning calorimeter (DSC). The samples were prepared by casting a
wet film of 254 .mu.m (10 mil) thickness and drying the film at
105.degree. C. Discs were cut from this dried film and 10 to 15 mg
of the sample were loaded into an aluminium DSC pan. The pan was
loaded into the calorimeter and heated to 105.degree. C. for 5
minutes to ensure that the sample is dry. The samples were then
cooled to -60.degree. C. and equilibrated there for 2 minutes. The
temperature was then increased at a rate of 20.degree. C. per
minute to 100.degree. C. The run conditions were consistent with
section 10.2 of ASTM D3418. The onset Tg is the value reported.
[0093] Carpet Tuft Bind values were determined according to ASTM
D1335-05. This procedure is a method to calculate the force
required to pull a loop or cut pile from a piece of carpet.
Equipment:
[0094] Instron Model 2519-105 (1000 N capacity) equipped with 7.62
cm (3 inch) jaw clamps, desiccator for conditioning carpet samples,
3.8 mm cylindrical specimen holder and loop hook.
Test Procedure:
[0095] Treatment of Samples for Testing Dry Tuft Bind:
[0096] All samples for testing were cut into 17.15.times.17.15 cm
(6.75.times.6.75 in) squares and placed in the desiccator with 25
to 35% humidity and 22 to 24.degree. C. for a minimum of 12
hours.
Additional Treatment of Samples for Testing Wet Tuft Bind:
Samples for Wet Tuft Bind are Prepared One at a Time According to
the Following Procedure:
[0097] After dry tuft binds are determined, the 17.15.times.17.15
cm (6.75.times.6.75 in) square is placed into a one gallon (3.8
liter) container that has been filled with cold tap water. The
carpet sample is submerged into the water and allowed to soak for
10 minutes. After 10 minutes the sample is removed and placed on a
paper towel for 30 seconds to soak up excess water. The carpet is
then taken to be tested for tuft bind values as previously
described.
Determination of Dry Tuft Bind and of Wet Tuft Bind:
[0098] Samples were mounted over the 3.8 mm holder with rows or
loops in line with the long axis of the holder. The carpet and
cylinder (specimen holder) were then placed into the jaws of the
Instron. Only loops with a minimum of 2.54 cm (1 inch) from the
sample edge were tested.
[0099] The loop hook was inserted in the loop to be pulled. By
visual inspection it was insured that only one loop was hooked for
testing.
[0100] The tuft was pulled at a speed of 304.8 cm (12 in) per
minute. The pull was continued until the tuft was separated from
the primary backing.
[0101] The maximum force needed to pull tuft was measured in
pounds. A total of ten pulls were made, averaged, and are reported
in Table 1.
Testing of Delamination Resistance:
[0102] Carpet Delamination resistance was determined according to
ASTM D3936-05. This procedure is a method to calculate the force
required to separate the secondary backing material from the
primary backing material.
Equipment:
[0103] Instron Model 2519-105 (1000 N capacity) equipped with 7.62
cm (3.00 in) jaw clamps
Desiccator for Conditioning Carpet Samples
Test Procedure:
[0104] Treatment of samples for testing Dry Delamination:
[0105] All samples for testing were cut into strips 7.62 cm (3.00
in) wide in the warp direction and 30.48 cm (12.00 in) long in the
machine direction and kept in the desiccator at 25% to 35% humidity
and 22.degree. C. to 24.degree. C. for a minimum of 12 hours.
[0106] Additional treatment of samples for testing Wet
Delamination: Samples for wet delamination were prepared one at a
time according to the following procedure:
[0107] An untested strip of the dimensions described above was
placed in a 3.8 liter (one gallon) container that had been filled
with cold tap water. The carpet sample was submerged into the water
and allowed to soak for 10 minutes. After 10 minutes the sample was
removed and placed on a paper towel for 30 seconds to soak up
excess water. The sample was then tested for delamination values as
described below.
Determination of Dry Delamination and of Wet Delamination:
[0108] The secondary backing was separated from the primary backing
approximately 3.8 cm (11/2 in) in the long (machine) direction on
each sample. The primary backing/pile was placed in the bottom jaw
as straight as possible, and the secondary backing was placed in
the top jaw for a 180.degree. peel configuration as straight as
possible. The two layers were pulled apart at a speed of 30.5 cm
(12 in) per minute for a total of 17.8 cm (7 in) of jaw travel.
[0109] No data were taken during the first and last inches of jaw
travel, and the highest value obtained in each of the five central
one-inch segments was recorded. The average of these five values
was divided by 3 (the width of the sample in inches) to provide
delamination strength in lb./in. Each such run was performed in
triplicate, and the average of these for each type of carpet is
reported in Table 1. The "% Retain" figures are the wet values as a
percentage of dry.
TABLE-US-00002 TABLE 1 Primary Coating Layer VAE VAE Secondary
Coating Layer VAE SBR Dry Tuft Bind N(lb.) 34.9(7.84) 33.1(7.45)
Wet Tuft Bind N(lb.) 13.9(3.13) 14.8(3.33) % Retain Tuft Bind 39.9
44.7 Dry Delamination N/cm(lb./in) 10.1(5.74) 12.6(7.22) Wet
Delamination N/cm(lb./in) 2.8(1.60) 3.6(2.03) % Retain Delamination
27.9 28.1
[0110] As seen in Table 1, the combination of VAE on the primary
backing and SBR on the secondary backing according to the invention
provided a 26% increase in Dry Delamination strength and a 27%
increase in Wet Delamination strength, compared with the use of VAE
on both backings.
* * * * *