Note: Descriptions are shown in the official language in which they were submitted.
Wo96/06685 2198597 r~
~E
250IST~rKE STABLE ~ a~KlNb CARPET
CROSS~ :N~. TO }?~T.~TEn .~PpLT~ N.~
S This application is a continuation-in-part of
co-pending application Serial No. 08j298,642 filed
August 31, 1994, now =hAnr~nnPd.
~ ~ . ' K ~ ) 1 I N I ~ O F ~T~ ~ N V ~ l r
Conventional tufted carpets are made by passing
a fleYible woven primary backing through a tufting
machine having a large array of needles that force the
carpet multif ilament yarn through the backing where the
yarn is restrained by a large array of hooks before the
5 needles are retracted. There may be about 1400 rleedles
across a 12-foot width. The backing must ar-nl ~r~Ate
needle penetration without damage. The backing is then
advanced a short distance (about 1/10" for a popular
high quality tuft density), and th2 needles are
20 reinserted through the backing to form the next series
of yarn tuf ts . A large array of cutters may be
employed in conjunction with the hooks to cut the tuft
loop inserted through the backing to produce a cut-pile
carpet . For loop-pile carpets, the tuf t loops are not
2, cut. Friction holds the tufts in the backing after the
needle has moved to the next position. However, this
friction is insufficient to hold the tufts in place
during use as a carpet, so an adhesive is applied in
liberal quantities to embed all the ~;1; q in the
3 0 base of the tuf t on the underside of the primary
backing (needle entry side). This prevents the pullout
of tufts or individual f;l: tc during use. To assist
in stAhil;7;n~ stiffening, strengthening, and
protecting the tuft base from abrasion, a secondary
35 r,acking is attached to the underside of the tufted
primary backing. The secondary backing may be attache~
by the same adhesive layer or by the application of
more adhesive . To save on costA, an; nP~rPnqive latex
W096/06685 21 9 8 5 ~ 7 r~".~
adhesive is most often used. The secondary ~acKlng
must resist damage during shipping, h~nril; n~ and
installation .
One problem with the above-described
S conv~nt;~7nAl carpets is their heavy structure. As a
result, these carpets can be difficult to install and,
after a useful life, are difficult to recycle since
many different polymers are used in their construction.
Nylon tufts, latex adhesive, polypropylene primary
10 backing, and polypropylene secondary backing are
commonly used. Tllese materia~.s are difficult to
separate for polymer recovery; latex and r.ylon polymers
are not c ~t;hle for recycle. This has resulted in
millions of pounds of waste carpet being dumped in
5 landfills each year.
Pr~ in~n~ly nylon ("all-nylon") carpets have
been suggested in the past. ~Iowever, nylon polymer
useful for backings in such carpets have a moisture
sensitivity that causes as much as 4% to 10~ changes in
20 the dimensions of the carpet in response to changes in
the humidity from very moist to very dry depending
somewhat on the temperature. These problems of moisture
and thermal stability have not been adequately
addressed in the past, so a carpet with a backing
25 structure that would constantly lay flat in use was not
possible. Moisture changes common in res;tiPnt;~l use
can result in large buckles in carpets where the carpet
is restrained in l v, ~ by contact with walls (in
wall-to-wall installations), or frictionally neld by
30 heavy furniture or spaced att~l t to floors. In
particular, moisture variations from near 0~ RH to near
100~ RK at elevated household temperatures are a
concern to the stability of carpets in re8i~nt; ~1 use .
Lightweight carpet constructions have been
3, suggested, but they have relied on the bulk application
of adhesives that are messy to handle in the
manufacturing process and are difficult to recycle with
the nylon polymer commonly used for the yarn tufts.
W0 96/06685 2 1 q ~ 5 9 7 1 ~
The m~l hln.oc sugyested for such lightweight
construction were ' _ to set up and operate as
they handled an entire carpet width of materials in a
continuous coupled process. They also usually required
discrete yarn supplies to feed the process and so
required extensive yarn restocking at intervals or
frequent stoppages to replace individual bobbins as
they randomly ran out.
There is a need for a carpet construction that
o is lightweight, dimensionally stable in use, and can be
recycled easily to produce useful polymers. There is a
need for an ~all-nylon" carpet that is stable to
moisture and temperature cllanges in use. There is a
need for a simple ;n~nqive method of making such
carpets.
The present invention provides such carpets and
methods f or making them .
STTMM~RY OF TTT~ lNv~ JN
The process and pile surfac~ structure (i.e.,
~tuftstring carpet assembly" or '~carpet~) of this
invention are ', uv, tq over the processes and
carpet constructions suggested in co-pending, co-
assigned U.S. Patent Application Serial No. 017,162
filed February 22, 1993, the disclosure of which is
hereby incorporated by reference. This application
describes a unique elongated pile article and a pile
surface structure (carpet) made using such elongated
pile articles and processes for making them.
3 0 The present invention is a lightweight,
moisture stable tuftstring carpet assembly made by
bonding a plurality of upright tuf ts of yarn to an
elongated strand, preferably reinforced, to make an
elongated pile article; and bonding a plurality of said
pile articles side-by-side to a lightweight backing
substrate, preferably a moisture stable reinforced
backing. A variety of material combinations for the
tufts, strand, and backing can be used to achieve the
21 ~8597 8
Wo 96/06685 PCr/US9S/1072
lightweight structure and moisture stability desired in
the carpet . The entire carpet can be made f rom a
moisture sensitive polymer, preferably nylon; the
reinforced strand is preferably a multi fi l t bundle
of fiberglass coated with a sheath of nylon; and the
backing substrate is preferably a laminate of
fiberglass scrim and non-woven I1ylon layers bonded
together in a sandwich structure. The fiberglass
resists the moisture expansion of the nylon, provides
0 some buckling st;ffnl~ss to resist shrinkage, and does
not cnnt=m1n~te the nylon polymer for recycle use. The
reinforced strand and backing have particular
structures that optimize the strength, weight, and cost
in a carpet structure. The moisture stability of the
carpet can be achieved by a synergism between the
reinforced strand and backing after assembly, or the
individual strand and backing each can be inherently
moisture stable and are assembled in a way to retain
this moisture stability after assembly and provide a
2 0 moisture stable structure .
The invention is also a method of making a
moisture stable tuftstring carpet assem.bly by using
ultrasonic energy to bond the yarn to the reinforced
strand, and the ~lnn~t~d pile article to the
reinforced backing substrate.
~T7TT;'Ti' Ll~,.s~ UN OF TT~ FIG~ S
Figure 1 is a diagrammatic view of one process
for making an elongate pile article.
Figure 2 is a cross-sectional view of a support
strand .
Figure 3 is a diagrammatic view of one process
for making a pile surface structure (tuftstring carpet
assembly) using elongated pile articles.
Figure 4 is an exploded view of a backing
f abric .
Figure 5 is a diagrammatic end view of a
portion or a pile surface structure.
WO 96/06685 ~ 2 1 9 8 5 9 7 1 ~ I"~ s~
Figure 6 is an enlarged diay, _ t, C view of
the guiding and bonding devices of Fig 3.
Figure 7 is a partial end view of the guiding
and bonding devices of Fig 6.
5 Figure 8 is a close up view of the elongated
pile articles and the ultrasonic horn.
Fig~lre 9 is a diagrammatic view of a plurality
of tuftstrings showing variations in the tufts and
strands .
Fig~re 10 is a diagrammatic view of an
alternate system for assembling tuftstrings to a
backing .
DET~TT.T.'n r)~Z.~'K I 1~ JN OF TT7~ lNV~I~LlUN
The present invention provides a ~moisture-
stable tuftstring carpet assembl~". By the term
"moisture-stable tuftstring carpet assembly~ or
~moisture stable carpet~, it is meant a tuftstring
carpet assembly (pile surface structure) which may be
manufactured by the methods described below, wherein
the length li r^n~inn of the assembly irl both the
tuftstring direction (T/SD) i.e., the machine direction
(MD), and the cross-tuftstring direction (XD) changes
2% or less in response to a change in the humidity from
100% to 3% or less at a temperature of 40C.
Preferably, the change in length in both the T/SD and
XD is 1% or less ~spe~ ;~lly when the carpet assembly is
intended for use in a large area and is to be secured
to the floor only at spaced locations or only around
the edges. The moisture stability of the tuftstring
carpet assembly and its individual ~ lLs ~ i . e .,
support strand and backing substrate as described
further below, is measured per the tests described in
the Test Methods below.
By the term ~moisture sensitive tuftstring
carpet assembly~, it is meant a tuftstring carpet
assembly, wherein the length dimension of the assembly
in the tuftstring directi~n (T/SD1 and/or the cross-
2 1 9 8 5 9 7
Wo 96/0v~685 1 ~ I
tuftstring direction (XD) changes greater than 2~6 in
response to a change in the humidity from 100~ to 3~ or
less at a temperature of 40C.
Figure 1 shows an apparatus and method of
making a single ~ n~t~d pile article, or "tuftstring~
by attaching plied carpet yarn 20 to a reinforced
support strand 32. The strand 32 is guided along the
edge 40 of a mandrel 30 and the plied yarn 20 is
wrapped around the mandrel and strand by rotating
eccentric guide 26. One or multiple strands may be
wrapped at once; t~vo are shown at 20a and 20b. The
yarn 20 is ultrasonically bonded to the strand 32 as it
is pulled under ultrasonic horn 42 by -- v. t Of
strand 32 and other carriers 134 and 136. The wrapped
yarn 20 is cut by rotating bIade 44 that intersects
mandrel slot 47 so the strand with bonded yarn attached
can be removed from mandrel 30 and guided to further
processing steps as at 200. The above-described
process and th~ tuftstring product produced is
discussed further in the Patent ~pplication Serial No.
017, 162 reference.
Figure 3 shows an apparatus for carrying out
further processing steps on the tuftstring. The
apparatus of Fig 1 is shown in the left of Fig 3 and
the further processing steps are shown beginning at
position 200. The single tuftstring 45 passes over a
slotted driven roll 202 where the tuftstring may ha~e
the pile height trimmed to a desired height by electric
shears 204, and then proceeds to a forwarding and
tensioning asse~bly 206. The tuftstring 45 proceeds to
a lathe type device 208 on which is mounted a large
cylinder 210 for winding the,tuftstring onto a backing
f abric in a spiral array . Mounted f or travel along the
guideways of the lathe device 208 is a carriage 212
that includes tensioning and guiding devices 214 and
ultrasonic bonding devices 216 for attaching the
tuftstring to a backing 218 held on the cylinder 210.
Flexible lines shown at 220 are for directing
2 1 9 ~ 5 9 7
wo 96/06685 r~
electrical power, control signals, and compressed air
to and from the moving carriage 212.
In Fig 3, after the tuftstring 45 has been
traversed the length of the cylinder 210 (from left to
5 right in Fig 3 in the direction of arrow 221) and
bonded along the length of the tuftstring to the
backing 218, a pile surface structure (tuftstring
carpet assembly), 222 is produced on the cylinder. By
slitting the structure along the axis of the cylinder,
10 the structure can be removed from the cylinder and laid
flat like a convpntinnAl carpet. The carpet may be
subject to additional treatments, such aq dyeing and
bulking, after removal from the cylinder, or some
treatments may be accomplished before removal from the
5 cylinder. For instance, it is possible to place a
housing around a portion of the cylinder surrounding a
section of bonded carpet and supply a heated f luid to
the housing to bulk the carpet on-line.
The reinfo~ced support strand 3~ is preferably
20 a multifilament bundle of fiberglass coated with nylon
which provides a moisture-stable, structural, adhesive
strand as described in co-pending, co-assigned U. S .
Patent Appl;c~t;~n Serial No. 08/270,861, filed July 5,
1994, the ,1;.ccl~sllre of which is hereby incorporated by
25 reference. By the term, ~moisture stable support
strand" it is meant a strand, wherein the length
dimension of the strand changes 2~ or less in response
to a change in the humidity from 100~6 to 3~ or less at
a temperature of 40C. Preferably, the change in
30 length is 1~ or less, especially when the strand is to
be used for large area carpets which are secured to the
f loor .
Referring to Figure 2, the strand 32 preferably
comprises a core 201 of crmt;nl~us glass reinforcing
35 filaments and a nylon sheath 203 :,u~ ~ uul~ding the core.
The nylon sheath is preferably adhered to the periphery
of the core and the strand preferably has a cross-
sectional area ratio of glass to nylon of 0.10 to 0.30.
21 98597
PCI/US95/10728
WO 96/06685
The reinforcing f;l; -nt.q (e.g., glass) of the
strand are substantially insensitive to moisture (i.e.,
the filament ' s length is substantially unchanged due to
changes in humidity) and the f ilaments have 1 ess than
5 0.209~ water pick-up. The reinforcing f;1. -c should
have a modulus per unit density of at least f ive times
that of the th~:L ~lAqtic resin (e.g., nylon) used for
the sheath. Preferably, the reinforcing fil q are
multif;li q of glass, ceramic fiber or carbon fiber.
l0 The carbon fibers may be pitch-derived carbon fibers
obtained from petroleum or coal tar pitch, or PAN-type
carbon fibers obtained from acrylic fibers. The glass
may be continuous strand-type or staple-t}~pe.
Cont;nl1n~lq-type glass is preferred. The ceramic fibers
may be SiC fibers, SiN fibers, BN fibers or alumina
fiberi;. Organi.c polymeric f;li ntc having the
requir~d moisture stability and modulus/density may
also be used. It is also recognized that monof; 1. tq
may be used.
The tht:L, ~lAqtic resin which can be used as a
sheath for the strand may be a polymer resin which is
considered substAnt;A11y insensit:ive to moisture such
as polyet~ylene tererhthA1 Ate (PET), preferably
"Dacron" PET, polypropylene, or the like.
~.lternatively, the polymer resin for the strand may be
considered substantially sensitive to moisture such as
a polyimide or a polyamide. Preferably, the resin is
nylon 6, 6 or nylon 6 . Nylon 6, 6 is especially
preferred. Recycled consumer ~r industrial waste
versions of these resins also work, and may make the
product easier to process and less expensive.
In other ~ t-q, it is not necessar~ for
the strand to 11ave a sheath/core structure. For
example, a strand comprising a nylon, polypropylene, or
polyester monofilament or multif;li c could be used
as illustrated below in Table I.
Alternatively, the strand may be a moisture
sensitiv6 structure. By the term, ~moiEiture aensitiv~
2 1 9 8 5 9 7 P~ s9sllo728
Wo 96/06685
~upport strand" it is meant a strand, wherein the
length dimension of the strand changes ~reater than 2~6
in response to a change in humidity from 100~ to 3~ or
less at a temperature of 40C.
- 5 The multifilament yarns which are used as the
tuf t yarns may be manuf actured by various methods known
in the art . These yarns contain f; l: - c ( f ibers )
prepared from synthetic thermoplastic polymers such as
polyamides, polyesters, polyolefins, and
0 acrylonitriles, and copolymers or blends thereof.
Natural f ibers such as wool may also be used .
Preferably the polyamide (nylon) is selected
from the group consisting of nylon 6, 6 or nylon 6
homopol"mer or copolymers thereof, sulfonated nylon 6, 6
or nylon 6 copolymer containing units derived from an
aromatic sulfonate or an alkali metal salt thereof,
nylon 6,6 or nylon 6 copolymer c~ntA;n;n~ units derived
from 2-methyl-pentamethyl~n~f~; Am; n~ (MPMD) and
;CorhthAl;c acid, nylon 6,6 copolymer c~ntA;n;n~ units
derived from isophthalic acid and ter~rhthAl; c acid,
and nylon 6,6 copolymer c ~ntA;n;n~ units derived from
N,N'-dibutylh, thyl~n~;Am;nP and dodecanedioic
acid. One preferred nylon 6,6 copolymer cr~ntA;nc about
l . 0 to about 4 . 0 weight percent of UIlits derived from
~he sodium salt of 5-sulfoisophthalic acid.
Preferably, the polyolefin is polypropylene
homopolymer or copolymers or blends thereof such as the
propylene,'ethylene copolymer described n co-pending,
co-assigned U. S . Patent Application Serial No .
08/419, 569 filed April 10, 1995, the disclosure of
which is hereby incorporated by reference.
Preferably the polyester is selected from the
group consisting of poly(ethylene terorhthAlAte),
poly(trimeth-~lene ter~rhthAlAte), And poly(butylene
ter~rhthAlAte) and copolymers and blends thereof.
Poly(trimethylene ter~rhthAlAte) is especially
preferred because it can be used to make fibers having
ur,i~ae carpet texture retention and ~,ear-reaistance
21 9~97
wo 96/06685 PCI/U595/10728
properties as described in co-pending, co-assigned U.S.
Patent Serial No. 08/268,585 filed June 30, 1994, the
disclosure of which is hereby incorporated by
re f erence .
These polymers are used to prepare polymer
melts or solutions which are extruded through
spinnerets to form f;l tR by techniques known in ~he
art such as those described in the above-referenced
applications. The polymer melt or solution may contain
lo additives such as W stabilizers, deodorants, flame
retardants, delustering agents, antimicrobial agents,
and the like.
In some instances, the multi fil - t yarns
conti~;n;nrJ these f;l t.q are subsequently dyed to
form colored tuft yarns. These yarns may b~ referred
to as pre-dyed yarns since they are colored prior to
manufacturing the carpet.
In other instances, a method known as solution-
dyeing may be used to make colored f; 1 i ~ ~ which are
then used to make ~he multifilament colored tuft yarns.
Generally, a solution-dyeing method involves
incorporating pigments or dyes into the polymer melt or
solution prior to extruding the blend through the
spinneret. Ill a carpet context, these may also be
referred to as pre-dyed yarns since the color is put in
the yarn before the carpet is tufted or otherwise
f ormed .
The pigment may be added in neat foam, as a
mi~ture with the above additives, or as a concentrate
3 o wherein t}le pigment is dispersed in a polymer matrix .
For color ronrontrates~ one or more pigments are
dispersed in a polymer matrix which also r~ntA;nC such
additives as lubricants a~d delustering agents (Tio2 ) .
The color c~ncontrate is then blended with the
~ilament-forming polymer and the blend is spun into
colored filaments. For example, U.S. Patent 5,108,684,
the disclosure of which is hereby incorporated by
reference, involvei~ a process where pigments are
Wo 96/06685 2 1 ~ ~ 5 9 7 pCT/US95/10728
dispersed in a terpolymer of nylon 6/6,6/6,10 and
pigmented pellets of the terpolyme~ are formed. These
pellets are then remelted or " let-dowrl" in an equal or
greater amount of nylon 6, mixed thoroughly to form a
- 5 uniform dispersion, resolidified, and pelletized. The
resulting color ~ ntrate is thell blended with a
nylon copolymer cnnti~;n;n~ an aromatic sulfonate or an
alkali metal salt thereof. The nylon melt-blend is
then spun to form stain-resistant, colored nylon
f;li q
Typically in a nylon f; ~: ' manufacturirlg
process, the molten polymer is extruded through the
spinneret into a quenc~l chimney where chilled air is
blown against the newly formed hot f i l i t.q . The
rilament ~ s cross-sectional shape is ~,~r~-n-l~nt upon the
design of the spilme-et. Preferably, the filament has
a trilobal cross-i.ection with a modification ratio (MR)
of about 1. 0 to about 4 . 0 . The cross-section of the
f;li ~q influences the luster (glow of the f; Ii t ,q
from reflected light), soil-hidin~, bulk, and hand
properties of the tuft yarns. The filament may contain
voids ~t~nA;n~ throug~ its axial core, as described in
U.S. Patent 3,745,061 or U.S. Patent 5,230,957. The
presence of voids in the f; 1 i t q inf luences the
luster alld soil-hiding properties of the tuft yarns.
The f; l i ts are pulled through the quench
zone by mearls of feed rolls and treated with a spin-
draw finish from a finish applicator. The f;li -q
are then passed over heated draw r~lls. Subsequently,
3 0 the f; ~ may be crimped .o make buiked cont i nll~)uS
f; li t (BCF) yarns . These yarns have randomly spaced
3-dimensional curvilinear crimp. .Dlte~natively, the
f;li ~ntæ may be crlmped and cut into short lengths to
make staple fiber. IIot air jet-bulking methods, as
described in U.S. Patent 3,186,155 or U.S. Patent
3, 525 ,134, may be employed to crimp and bulk the yarn .
Generally, for purposes of this invention, each yarn
has a bulk crimp elongation (BCE) of about 20~ to 50~,
11
8597
W096/06685 2 1 q
and a denier per filanlent (dpf) of about 16 eo 25. For
entangled f;li t, loop-pile tuftstring carpets with
good bulk, the BCE9~ may be toward the lligher end of the
abovc r t;nnPd BCE% range. For ply-twisted, cut-pile
tuftstring carpets with good hand, the BCE% should be
in a range of 27~ to 49i'~, preferably 319; to 43~. For
velour, cut-pile carpets with good resistance to
felting, the BCE9~ may be toward the lower end of the
above-mentioned sCE~ range.
0 If the yarns are intended for use in a cut-pile
~uftstring carpet structu-e, then these "singles"
nnPnt yarns may then be twisted together to form a
ply-twisted mult 1 f; 1: - t yarn . This ply- twisted
mult . ~i l i t yarn is constructed by cabling together
two or mo~e compollent yarns by such techniques as, ~or
exa~nple, a two-step twisting~cabling process or a
direct cabling process, as described in U. S . Patent
5,263,,08. The ply-twist may be unidirectional or the
twist may have alternate directions as described in
U. S . Patent 4, 873, 821. For purposes of this invention
it is preferable that the total denier of ehe ply-
twisted yarn be at least 2000 and more preferably in
the range of about 2400 to about 31û0. The ply-twisted
yarn is preferably a two-ply yarn with a twist level in
the range of about 3 to about 5 turns per inch (tpi).
Alternatively, the yarns may be false-twisted or air-
entangled ~lPrPn~;n~ on the desired carpet construction.
If a j~ly-twisted multifilament yarn is
constructed, it may then be "textured" by passing the
yarn through a stuffer box, where the yarn is
compressed and individual fi1i .c are folded and
bent. The yarn may also be heat-treated to set the
twist in the yarn. This heat-setting of the twist is
done if the yarn is intended for use in a cut-pile
carpet structure. These techniques are also well known
in the art. For example, the yarn may pass through a
"Superba" continuous heat-setting machine which treats
the yarn with prei~surized saturated 6team or a
12
- 21 98597
W0 96/06685
~Suessen" machine which treats the yarn with dry heat.
These yarns may then be used to construct the
tuf tstring carpet assembly in accordance with the
methods described herein.
In the f inal carpet assembly, the tuf ts may
have various forms such as, for example, loop-pile or
cut-pile. Loop-pile tufts are characterized by having
the yarn in the form of an uncut loop as described in
U.S. Patent .~pplication Serial No. 08/331,074, filed
0 October 28, 1994, the disclosure of which is hereby
incorporated by reference. Cut-pile tufts may be
obtained by cutting the loops of the tuft yarns or
preferably by the process shown in Fig. 1.
The final tuftstring carpet assembly may also
treated with stain-resist agents which provide
resistance to staining of the pile yarn by acid dyes.
These stain-resis~ agents include, for example,
sulfonated pbenol- or nArhth~l-formaldehyde c~n~lPncate
products and hydrolyzed villyl aromatic maieic anhydride
polymers as described in U.S. Patent 4,925,707. The
tuf tstring carpet assembly may also be treated with
soi'-resist agents which provide resistance to soiling
of the pile yarn. These soil-resist agents include,
for example, fluorochemical c~mpositions as described
in U.S. Patent 5,153,046.
Preferably, the tuft yarn cr~nt~inq fil --t':
made from a polymer that can be fusion bonded to the
selected pclymer of the strand by thermal fusion or
solvent fusion or the like, whereby the original
polymer used for the strand and tuft provide the means
for ~oining the strand and tuft, and the addition of a
separate adhesive material is not required. However,
the addition of a small quantity of adhesive materia
to enhance fusion bonding may be desirable.
~s Preferably, the tuft polymer and the strand polymer are
- the same polymer or of the same polymer family.
T~le backing substrate 218 must be "moisture
stable ~ in the direction perpendicular to the
13
21 98597
Wo 96/06685 PCrlU595/10728
tuftstring, i . e, the cross-machine direction (XD), and
it may or may not be moisture stable in the tuftstring
direction (T/SD), i . e ., the machine direction (MD) . By
the term '~moisture stable", it is meant that the length
5 dimension of the respective direction, (XD) or (MD)
changes 2~ or less in response to a change in the
humidity from 100~ to 3~ or less at a temperature of
40C ~
The "backing substrate" may De any suitable
10 sheet-like material ;nl lll~;n~ for example, fabrics
such as felts, wovens, non-wovens, knits, and flocs,
and films ~uch as slit film wov_ns.
By the tsrm "moisture stable backing
substrate~, it is meant a backing substrate, wherein
1, the length dimension of the substrate in both the
machine direction (MD) and the cross-machine direction
(XD) changes 2~ or less in response to a change in the
humidity from 100~ to 3~ or less at a temperature of
40C. Prefera~ily, the change in length in both the MD
20 and XD is 1~ or less especially when the substrate is
to be used for large area carpets which are secured to
tha floor. The th~ ~lA~tic polymer suitable for
making a moisture stable backing substrate may be a
polymer which is substAnt;Ally insensitive to moisture
25 slch as polyethylene terPrhthAlAte (PET), preferably
~acron~ PET, polypropylene, or the like.
Alternatively, the polymer of the backing may
be substAnt;Ally sensitive to moisture and be
stabilized in at least the XD with reinforcing
30 flli ~tci that are substantially insensitive to
moisture. This would result in what is referred to as
a "moisture sensitive hacking substrate", by which it
is meant a backing substrate, wherein the length
dimension of the backing in the machine direction (MD)
35 changes greater than 2~ in response to a change in the
humidity frGm 100~ to 3~ or less at a te~perature of
40C. Some moisture sensitive polymers useful for
making such a Dacking substrat~ include polyimides or
14
21 98597
WO96l06685 ~ JIiv/~i
polyamides . Preferably, tlle polymer is nylon 6, 6 or
nylon 6 . Nylon 6, 6 is especially preferred. Recycle~
consumer or industrial waste versions of these resins
also work, and T~ay make the product easier to process
5 and less expensive.
To achieve the required moisture stability and
structural stability in the finished carpet structure,
the backing substrate may be reinforced with
reinforcing fil: s or a reinforcing scrim. The
10 reinforcing f;l: c of the backing are substAn~iAlly
insensitive to moisture (i.e. the filament's length is
substAnt;Ally unchanged due to changes in humidity) and
the f;lA~-ntq have less than 0.20~6 water pick-up. The
reinforci~lg fili q should have a modulus per unit
15 density of at least five times that of the
thermoplastic pGlymer used to make the backing.
Preferably, the reinforcing filaments are
multif;li ntq of glass, ceramic fiber or carbon fiber.
The carbon fibers may be pitch-derived carbon fibers
20 obtained from petroleum or coal tar pitch, or PAN-type
carbon fibers obtained from acrylic fibers. ~he glass
may be c- nt;nllol~q strand-type or staple-type.
r~lnt;n~ llq-type glass is preferred. The ceramic fibers
may be SiC fibers, SiN fibers, BN fibers or alumina
25 fibers. Organic polymeric f;l: ntq having the
reG;uired moisture stability and modulus/density may
also be used.
The backing substrate 218 is preferably a
composite fabric of nonwoven nylon and fiberglass scrim
30 as described in co-pending, co-assigned U.S. Patent
Application 08/258,120, filed June 10, 1994, the
disclosure of which is hereby incorporated herein by
reference. Preferably, the composite fabric is a
moisture sti- ble backing substrate Re~erring to the
35 exploded view in Fig 4, the moisture stable backing
subst-ate 218 preferably comprises a first layer 213 of
a nonwoven fabric of entangled, non-bonded nylon
filaments, a second layer 215 of fiberglass f~cri.m, and
-
Wo 96/06685 2 1 9 8 5 ~ 7 PCI/US95/10728
a third layer 217 of a nu~ v~l fabric of encangled,
non-bonded nylon f; l: q . Each layer of nonwoven
nylon fabric is adhesively attached to the layer of
fiberglass scrim ~1~' ;n~ntly at the contact surface
5 between the fabrics and scrim so most of the non-bonded
nylon f;l: ~q remain non-bonded. Preferably the
adhesive is an acrylic adhesive.
When the above preferred backing is a thin
backing of 1 o ~/s~ yd "Sontara" n~ Ov~ l nylon fabric
10 attached to the top and bottom of an 8 x 8 scrim of
10 0 0 denier mult; f; 1: ' f iberglass, the cylinder 210
of Fig. 3 is preferably covered with a thermal
insulative coating that slows the heat flow from the
ultrasonically heated carpet elements to the cylinder.
15 This is believed to make the ultrasonic heating more
efficient. One such coating that has been found to
work is a TFE coated fiberglass made by the CHEMFA~3
company in Merrimack, NH, designated Premium Series
350-6A. An acrylic adhesive may be used to attach the
2C coating to the metal cylinder. The TFE surface keeps
the backing substrate from sticking to the coating.
The thickness of the coating may provide some
resilience to the cylinder surface to reduce
concentrations of force due to dimensional variations
25 in the elements that may produce ~hot spots~ as the
tuftstring is bonded to the backing. If a thicker
backing structure is used that provides some load
distribution during bonding, or if the speed of the
tuftstring under the horn is greater than about 10
30 yd/min ~o ~ignificant heat transfer to the cylinder
cannot occur in the time available, then such a coating
may not be needed.
Figure 5 is a typical partial end view of a
m.oisture stable carpet (made on the ~evice of Fig . 3 )
35 viewed in a direction perpendicular to the axis of the
cylinder and parallel to the elongated axis of the
tuftstring. ~ach of the cut tuftstring segments 45 a-h
comprises a plurality of bundles of filaments, or
16
Wo96/06685 i~l -9 8 5 9 7 PCI/US95/10728
tuft, secured to support strand 32. ~or instance,
filament bundle 46 is bent in the shape oE a ~U~
def ined by a pair of upstanding tufts 52 and 54
P~tpn~;ng~ upward from a base 224 and spaced from each
5 other adjacent the base at 226. Each of the bundles
has a dense portion of f;li~r-n~q 62 bonded to each
other and secured to t11e peripheral surface of the
support strand 32 at the base. Each of the bundles
forms an acute angle with the dense portion at the
10 base. The supporl: strand has a wldth 74 that is equal
to or less th~n the distance between the upstanding
tufts. The tuftstrings are spaced a selected distance
apart, such as at 226, based on the desired dellsity or
~ufts on tne ca-pet, and are bonded aiong th~ir length
S tG the surface 22a of backing 21~. In t~1e embodiment
shown, the reihforced s~lpport strand 32 is bonded on
the inside cf the "U'~ shaped bundles, and the bottom
side of the tuftstring, that is, the bottom of the
bonded '~U~ shaped bundles, is bonded to the surface of
2 0 the backing . Tn another embodiment, the stxand may be
bonded to the ~utside of the ~'U" shaped bundle, and
then the strand wo~lld be bonded co the su~f ace of the
backing when attaching the ~uftstring to the backing.
Preferably, the tuftstrin~, or pile article,
2 5 comorises a support strand having a surf ace of
thermoplastic polymer, and a plurality of bundles of
fili nts of thermoplastic polymer, each bundle
defining a pair of t:uf1:s":he tufts in said pair bent
at an angle at a base and eYtPn~;;nS upwardly therefrom,
30 'he tufts defining a spaced distance therebetween
adjacent said base, each of said bundles having a dense
portion of fili - rq ronded together and secured to the
surface of the support strand at said ~ase by fusiorl of
the thermoplastic polymer of the support strand and the
35 f;li q, said support strand having a width that is
equal to or less than the distance between the tufts in
said pair.
l7
Wo 96/06685 2: ~ 9 8 5 9 7 PCrlUS95/10728
It is important that the tuf tstring be
carefully guided onto the cylinder 210 and under the
ultrasonic bonding device 216. Figure 6 is a close-up
view of a portion of Fig 3 showing the t~lftstring 45 as
it is guided onto cylinder 210, covered with backing
218, by tensioning and guiding device 214. The
ultrasonic bonding device 216 consists of at least one
ultrasonic horn 230 and ultrasonic driver 232 attached
to a flexible mount 234 that allows the horn and driver
lG to move freely in a radial direction relative to the
cylinder. An arm 236 on the mount 234 permits weights,
such 25 weight 238, to be added to control the force
the horn exer~s on the tuftstring. The tensioning and
guiding device consists of V-groove tensioning wheels
240 and 242, guide wheel 244, guide groove 245, and
other guides better seen in Figures 7 and 8. The V-
groove in wheels 240 and 242 keeps the tuftstring
upright and grips it so the magnet ~ c ~orque of the
teRsioning wheels can -e.sist the pull of the tuftstring
by the rotating cylinder, and thereby apply tension.
The magnetic t~nq;nn;n~ wheels can be obtained from
TEXTR~L, INC. of Monroe, NC. The tuftstring twists 90
degrees between t~nqi~n;ng wheel 242 and guide wheel
244 which also has a V-groove. The tensioning and
guidillg deYice 214 and bonding device 216 are attached
to frame ~nember 246 that is attached to traveling
carriage 212.
Figure 7 is view 7-7 from Fig 6 that shows
further details of how the tuftstring may be guided.
lt is important that ~he upstanding tufts of the
adjacent tuftstring already on the cylinder do not get
trapped under the ; nl ' n~ tuf tstring being bonded to
the backing on the cylinder. It is also important that
the ; n~_ ; n~ tuftstring be positioned with the tufts
upright and the strand directly under the ultrasonic
horn. To accomplish these erlds, in Fig 7 a guide rod
250 is attached to frame member 246 and follows the
contour of the cylinder close to the backing and
1~
` 2 1 9 8 5 ~ 7 Pcr~ sgs/lo728
wo 96/06685
presses sideways against the upstanding tufts of
tuftstring 45j to hold them away from the incoming
tuftstring 45k ar~d ultrasonic horn 230. A guide plate
248 is attached to guide rod 250 and is placed close to
5 the backing 218 and at an angle to the bonded
tuftstring 45j. Another guide rod 252 is attached to
frame member 246 and is placed close to the ;nr 'n~
tuftstring to keep the upstanding tufts upright and
assist in guiding the incoming tuftstring 45k under the
1~ horn 230. Figure 8 shows another view 6-6 from Fig 7
of guide rods 250 and 252 just in front of the horn
230. Guiding of tuftstrings 45j and 45k keeps the
tu~ts from getting bent over and trapped under the horn
230 or between the tuftstring 45k and the backing 218
lS during bonding. To assist in alignment of the
tuftstring under the horn, the leading edge 254 of the
horn 230 (Fig 7) is radiused and this edge and the
bottom edge are contoured to receive the strand that
comes in direct contact with the surface of the horn.
In the case of an elliptical strand surface (after
bonding with the yarn), these horn edges would be a
concave radiused surface which can be seen in Fig ~ at
bottom sur~ace 256. During high ellergy vibration of
the horn this contoured surface he~ps keep the strand
from sliding out from ,mder the horn.
Fig 7 also shows another ultrasonic horll 258
that is useful when assembling the tuftstring to the
backing at high speeds, such as about 10-25 YPM
t-~ftstrillg speed, and when high bonding rr~ hi ~; ty is
required. Horn 258 is located close to horn 230 so the
tuftstring 45k is s':ill hot f~om horn 230 when it is
bonded by horn 258. In this way, the heating is
partially cumulative and the total energy needs for
bonding call be shared by two horns. This permits
operating at high speeds which requires high bonding
- energy. At low speeds, secoll~ horn 258 is useful for
'~re-bonding" the tuftstring and improving bond
reliability by bonding areas that may hdve been rl~ifiaed
19
- 2 1 9 8 5 9 7 PCl/US95/10728
wo 96/0668~
by horn a30. It may also b,~ useful to use horn 230
iust to accurately tack the tuftstring in place with
low vibration and force, and use horn 258 to firmly
attach the tuftstring with high energy and force
5 without the problem of the tuftstring moving around
under the horn before bonding. This two horn technique
may also be useful for attaching pile yarns to the
support strand, particularly at high speeds.
Bonding means other than ultrasonic bonding may
0 be employed to attach the yarn bundle to the strand and
to attach the tuftstring to the backing. Such means
may be solvent bonding or thermal bonding with, for
instance, a hot bar; or some combination of solvent,
conductive, and ultrasonic bonding. It is preferred
15 that the bonding occurs without the separate addition
of adhesive n~aterial to the tuftstring or backing when
joining the tuftstring to the backing, however, it is
within the scope of the invention to include the
addition of adhesive in the bonding area to achieve
20 bonding between ~;.cs;m;l~r thermoplastic polymers or to
enhance ultrasonic bonding. Bonding using an adhesive
may also be achieved using methods described in above-
referenced co-pending U.S. Patent Application Serial
No. 07/017,162. When using an additional adhesive
25 , , ~lnPnt, care must be taken that the adhesive type
and quantity used does not ~ . ;.qe the moisture
stability of the resulting assembly.
In operation of the device of Figs. 1 and 3,
yarn from source 22 and strand from roll 33 are fed to
3G mandrel 30 where t~e strand travels along ridge 40 and
to d~ive roll 201 in the forwarding and ~n.cir~n;
assembly 206. The yarII 20 is wrapped around the
mandrel and strand and bonded to the strand b~
ultrasonic horn 42 to make tuftstring 45. The
35 tuftstring is tnreaded through the appara-;us to
cylinder 210. Backing 218 is attached to cylinder 210
by tape 211 and is wrapped around the cylinder and cut
to form a butt seam and taped to itself hy t~pe 213 ae
~ 1 9 ~ 5 q 7 Pcr~Us95/10728
WO 96/06685
shown in Fig 7. The end of the tuftstring is threaded
under the horn 230, and horn 258 if used, and taped to
the backing at the far left of the cylinder 210 where
the carriage 212 is positioned for startup. Rotation o~
the cylinder 210 can now be started and the ultrasonic
horn energized to bond the tu~tstring to the backing;
the cylinder 210 acts as the ultrasonic anvil.
Carriage 212 is geared to the cylinder rotation so it
traverses the desired pitch, say about 0.2~, for one
o revolution to advance the tuftstring along the cylinder
and buildup a spiral array of tuftstring on the backing
on the cylinder. When the carriage has traversed ~
the way to the right of the cylinder, the process is
stopped and the carpet wound on the cylinder is cut
along the tape seam for the backin~ and removed from
the cylinder. The process can then be repeated. To
control the speed and tension in the process, the speed
of cylinder 210 can be constant and tuftstring drive
roll 201 can vary slightly in speed to keep the tension
monitored by tensiometer 211 constant. The speed of
strand forwarding roll assembly 207 can also vary
slightly in speed to keep the tension monitored by
tensiometer 209 constant.
Although the system shown in Fig 3 for making
the carpet winds onl~ a single tuftstring, it is within
the scope of the invention to wind multiple tuftstrings
and provide an ultrasonic horh that has multiple blades
closely spaced for bonding multiple tuftstrings
simultaneously using a single ultrasonic energizer. A
3 0 plurality of these multiple blade horns could be
arranged along a cylinder so numerous tuftstrings could
all be bonded at- once and a complete carpet made
rapidly with only a few complete revolutions of the
cylinder .
Although the system for automated assembly of
tuftstring to a backing in Fig 3 shows the pile surface
assembly being made with the backing on the inside and
the tufts on the outside with the ultrasonic energy
21
2 1 ~ 8 5 ~ 7 ~ )..5J~
WO 96/06685
being applied from the topside of the backing, the
opposite construction with the pile on the inside and
the backing on the outside is possible with the
ultrasonic energy being applied from the ha~ kqi~iP Of
5 the backing. Fig lO shows a diagrammatic view of an
alternate embodiment where the cylinder 280 has a
c~ntin~ us helical rib 282 on the surface to support
the tuftstring 284. There are spaces, such as spaces
286 and 288, on both sides of rib 2B2 to receive the
10 tufts. The rib would have a groove 290 to receive the
strand and prevent the strand from slipping off the rib
and into the space between ribs. The tuftstring 284
would be wrapped under tension along the cylinder on
the ~.elical rib without any bonding to a backing. The
15 backing 292 would then be fed onto the cylinder and
wrapped around the tuftstring and secured as with tape.
A wide ultrasonic horn 294 Sp~nnin~ several ribs could
be used to progressivel y bond the backing to the
tuftstring from one end of the cylinder to the other as
20 the cylinder makes several revolutions. The assembled
backing and tuftstring would then be slit axially along
the cylinder and the pile surface structure, or carpet,
removed and rolled out flat.
Although the systems shown in Figs 3 and 10
25 show a batch process for making a carpet assembly, it
is within the scope of the invention to make a
c~nt i nll~us length of carpet by a warp process where
there are enough tuftstrings fed to the cylinder for an
entire carpet width, and the cylinder serves as an
3 0 anvil and a transport roll in the process . The backing
would only make a partial wrap around the cylinder
sufficient to bond the plurality of tuftstrings using
multiple ultrasonic horns. In the Fig 3; ' o~i- t
where the tufts are facing ou.ward from the cylinder,
35 one horn may have a plurality of blades for bonding a
plurality of tuftstrings at once. In the Fig 10
embodiment where the tufts are facing in toward the
cylinder, the cylinder would have a plurality of
22
2 1 9 8 5 9 7 ycr/us95/10728
Wo 96/06685
parallel ribs or discs (rather than a rnnt;nlln~lq
helical rib) to support all the tuftstrings as they
wrap partially around the cylinder and are bonded by a
plurality of horns, with each spanning several ribs.
5 In botn cases, the tuftstrings may be supplied inline
from a plurality of mandrels, or the tuftstrings may be
- nlade off-line and supplied from rolls or piddle cans.
The pile surface article shown in Fig 5
provides a very lightweight carpet structure. A
10 conventional tufted cut-piie carpet with the n~Crs~ ry
latex adhesive and secnn~ ry backing typically has
about 50~6 of its weight in the tufting yarn and about
50~ in the hacl~in~ and latex for a 30 oz/sq yd carpet
(yarn weight). The lightweight carpet of the invention
5 has about 75~ of its weight in the yarn and only 25~ in
the backing. For a typical roll of 30 oz/sq yd carpet
n~nta;n;n~ about 120 sq yd of carpet, the roll weight
of a conventional carpet would be about 200 pounds more
than a roll of carpet made according to the invention.
20 For the convF~ntinnill carpet, this results in higher
shipping costs, more strenuous installation, and more
waste in the 1 i~n~f; 11 when the carpet is worn out . The
latex in the convrntlrni~l carpet, that contributes to
the higher weight, also is very difficult to
25 mechanically separate from the nylon face yarn and is
very difficult to chemically separate from nylon
polymer, and so makes recycling of the nylon
economically unattractive. The nylon face yarn and
nylon backing in the carpet of the invention can be
30 2asily recycled together without chemical co~ti~m;ni~tion
by the fiberglass reinforcing f;li t~.
The tuftstring carpet of this invention may be
bulked after it has been assembled. This bulking
provides the carpet with grea.er covering power. The
35 pile yarn is fllrther bulked by heating the pile of the
tuftstring carpet. In one bulking operation, as
described in co-pending, co-assigned US Provisional
~pplication entitled "Method for Bulking Tuftstring
23
~ 2 1 9 8 5 9 7 ~/usgsllo728
Wo 96/06685 P
Carpets ", the disclosure of which is hereby
incorporated by reference, the tuftstring carpet is
placed or. a tenter frame and passed through an oven,
where tlle pile yarn is heated with a rapidly flowing
5 stream of hot air and then cooled. In the case of
nylon 6,6 multifilament pile yarn, the air temperature
is in the range of about 90 to 150C which raises the
temperature of the tuft f;l. q throughout the pile
yarn to at least 90C.
The invention is also useful for making
moisture stable carpet structures which do not
incorporate nylon in some or any of the elements. For
instance, the moisture stable backing may be a
convPnt-~nAl polypropylene backing that is a moisture
5 stable polymer, and a nylon tuftstring could be
attached using a hot melt adhesive. The adhesive
should have a melting point that is higher than the
melting point of the nylon tuftstring and higher than
the polypropylene backing to cause some melting of the
20 carpet elements and achieve good bonding. Since the
nylon melt point is higher than the polypropylene, the
hot adhesive should f irst be applied to the nylon and
then allowed to cool, - ~Arily before contacting the
polypropylene. Such a&esives that should work are
25 PEEK (polyetherether ketone) or polyimide adhesives.
It may also be possible to achieve an adequate bond
using a low melting a&esive that f lows around and
mechanically engages the f; l . -q in the tuftstring
and backing . 9uch adhesives may be convPnt; ~nA 1 hot
30 melts made from copolymers of nylon. In Fig. 6, the
a&esive may be applied to the bottom of the tuftstring
at the position of guide 245. It may also be possible
t~ use a curable adhesive, such as an epoxy adhesive,
instead of a hot melt, as long as the epoxy is tacky
3 5 enough to hold the tuf ~string in place on t:he backing
on the cylinder until the adhesive cures. Heat could
be applied to the carpet on the cylinder to accelerate
the cure, which may also assist in bulklng the tuLts.
24
21 ~5~7
PCI/US95/10728
WO 96/06685
For recycling the carpet elements, it should be
possible to peel the tuftstrings from the backing with
the aid of heat or chemicals to soften the adhesive.
The separated different polymer elements could then be
5 easily recycled.
The following Table I S~IOWS a matrix of some of
the combinations that are illustrative of the moisture
stable carpet assembly of the invention. Following the
g~ ;Pl inPq taught herein, other combinations using
l0 other polymers may also be possible.
~ABLE
MOISTURE
15STABLE
CARPET
ET,~MFNTS ILLUSTRATIVE MATERIAL COMBINATIONS
TUFTSTRING
2 0- tuf t N N N PET PP N N N
- strand N/G N/G N PET PP N N N/G
BACKING
- ~CD N/G N/G N/G PET PP PP/G PET/G PP
25 - Mr N/G N N/G PET PP PP/G PET/G PP
SEPARATE
BONrING
AD~IESIVE no no no no no yes yes yes
3 o (TS to backing)
(NOTE: N = nylon; G = glass; PET = polyethylene
terPrhthi3lAte; PP = polypropylene; N/G = nylon
sheath surrounding a core of glass f i 1: q;
35 PP/G = polypropylene sheath i,uLLuu.. ding a core
of glass f i 1 i ~ q; PET/G = polyethylene
tererhrh~ te sheath surrounding a core of
glass fili r~.)
When, ' ;n;n~ moisture stable and moisture
sensitive materials to achieve a moisture stable pile
surface structure (tuftstring carpet assembly), there
are three important considerations for the structural
~5 elements such as the strand and the backing. These
are: l) the moisture response of ~:he individual
2 1 q 8 5 9 7 pcr/U595ll0728
Wo 96/06685
element; 2) the longitudinal or in-plane stiffness of
the individual element; and 3 ) the desired moisture
response of the composite structure. When a moisture
sensitive element i5 1" ' ;n~d with a moisture stable
5 element, the moisture response of the composite element
can be determined using composite design theory.
Basically, the stiffness ratio of the moisture stable
element to the moisture sensitive element, for instance
the backing compared to the strand, must be greater
0 than a value which can be estimated and then adjusted
based on experimentation.
The stiffness ratio can be expressed as
follows:
Sb/Ss = ~Es - Ec) / (Ec - Eb),
where Sb is the stiffness per width increment
of the moisture stable element (such as the backing),
Ss is the st; ffnP.cs per width inoL- nt of
the moisture sensitive element (such as the strand),
Es is the maximum moisture responsive strain
20 of a strand,
Ec is the maximum moisture responsive strain
of a unit width of composite carpet structure
associated with a single strand, and
Eb is the maximum moisture responsive strain
25 of a unit width of backing associated with a single
s t rand .
Note that Ec should always fall somewhere
between Es and Eb. In the case of an unreinforced
nylon strand with Es= . 03 and a glass reinforced nylon
30 backing with Eb=.005, and a desired moisture responsive
strain in the composite structure of Ec= . 01, the
stif fness ratio would be 4 . That is, the backing needs
to be about 4 times stiffer than the strand.
Specifying the strand denier and the polymer used for
35 making the backing, the denier of the desired
reinforcing filament can be calculated and used as a
starting point for experimentation. Other variables,
such as the degree of adhesion between the elements,
26
Wo 96/06685 2 1 q 8 5 9 7 PCT/US95/10728
the draw stress in the polymers of the Pl I - c,
polymer additives, and the like will affect the final
composite performance, and some adjustment in the
stif fness of the Pl ~ ~ c may have to be made to
- 5 achieve the desired composite performance.
There are also other variations possible with
the carpet assembly of the invention using tufts
attached to a strand to form tuftstrings that are
attached to a backing. By providing multiple yarns in
the yarn supply 20, such as 20a and 20b, and winding
them on the mandrel 3 0 as shown in Fig 1, it is
possible to distribute a variation in the yarn in a
controlled manner throughout the face of the carpet.
Although variations in the cross direction (XD) are
possible in both the convPnt;nn=l and tuftstring
carpets by making variations in the yarns from one
strand to the next or one tuftstring to the next in the
XD, variations in the MD are not possible in the case
of a convPnt;~n~l tufted carpet that introduces only a
single r~nt;nllrnlc strand repeatedly in a straight or
zigzag line in the machine direction (MD) of the
carpet. It may be desired, for instance, to sparsely
introduce a particular effect throughout the face of
the carpet. Such an effect may be a colored yarn, an
antistatic yarn, an antimicrobial yarn or one with
other chemical features, an ;np~rpncive yarn, a yarn
with different texture, twist level, finish, denier,
etc. For instance, the supplied yarn 20 for one
tuftstring may comprise three yarns with only one of
them being the desired effect yarn, and the next
adjacent two tuftstrings assembled to the backing may
not have the effect yarn at all. The effect then is
distributed sparsely in both the MD and XD of the
carpet .
Referring to Fig 9, tuftstring 260 has 1/3 of
the pile yarns, such as shaded yarns 262a and 262b
c-~nt:~;n;n~ antistatic fil: tR, Tuftstrihgs 264 and
266 do not contain any yarns with antistatic ri.larrl~rltlJ
27
WO96/06685 2 1 9 8 5 9 7 PCr/US95/10728
Tuftstring 268 also cnnti~;nq antistatic f;l !.q in
the pile yarns, such as shaded yarns 270a and 270b.
This provides a controlled distribution of an effect
yarn throughout the f ace of the carpet of the invention
5 in both the XD and MD.
The use of a Cnnt; nllnus strand in the carpet
assembly offers the poss;h;l;ty for additional
variations in the carpet of the invention which would
not be possible with conventional tufted carpets
0 wi.thout costly additional steps after the carpet has
been formed. For instance, antistatic f;l: ~.q may be
incorporated in some or all of the tuftstring support
strands by blending it in with the f iberglass f; l; t
bundle in the core of the strand during strand
15 formation. This would be combined with antistatic
f;li s in some or all of the tuft yarns to provide
,~nhi~nn.od antistatic performance for computer rooms and
the like where low static voltage buildup is important.
The antistatic f; l .q in all the strands may be
2 0 grounded .
Referring to Fig 9, tuftstring 260 with
antistatic tuft yarns has antistatic filaments 272 and
tuftstring 268 with antistatic tuft yarn has antistatic
f;1: tq 274. These filaments can extend cnnt;nl~m~qly
25 across the width of the carpet as can be seen with
f;li tfi 27~ at the opposite end 276 of tuftstring
268. Both ends of f;l: ~q 274 could be grounded to
enhance static removal from the carpet.
It may also be possible to transmit signals
3 0 f rom one edge of the carpet to the other through the
strands by incorporating a Cnnt; n~lous strand of wire or
an optical fiber in the fiberglass bundle in ~ome or
all of the tuftstrings. In the case of a wire, it
cou' d also function as an antenna, an electromagnetic
35 shield, or a tracking wire for guiding a robotic
vehicle along the carpet surface from one edge of the
carpet to the other in a predetermined path. Such a
robotic vehicle may be a vacuum cleaner that could
28
2 1 9 8 5 9 7 CrNSgs/10728
Wo 96/06685 P
automatically travel back and forth across the carpet
f or cleaning . The signal could also be used in
conjunction with an electronic pet control collar to
restrict pet access to all of the carpet or to certain
parts of the room. If a small insulated wire is used
in the strand, with a polymer coating different than
the strand polymer, it could also serve to transmit
electrical power safely from one edge of the carpet to
the other. Other variations in effects and
functionalities that are inherently poss~ble with the
tuftstring carpet assembly will be evident to those
skilled in the art using the teachings herein.
The present invention is further illustrated by
the following Examples using the below Test Methods,
but these Examples should not be considered as limiting
the scope of the invention.
TE~T M~!T}IODS
Moisture St~hility
The following procedures, Test A or Test B, are
used for measuring the moisture stability of the
tuftstring carpet assembly (pile surface structure).
Test A:
1. Fabricate a finished piece of the
tuf tstring carpet .
2. Cut at least 5 samples out of the carpet
piece . These samples should measure 4 0 cm long in the
tuftstring direction (T~SD) and 40 cm long in the cross
3~ direction (XD), i.e., 90 degrees to the tuftstring
direct ion .
3. On t~le back of each sample, draw a line
through the ~enter of the sample f rom edge to edge in
the T/SD and XD and place a staole across each line at
2 . 5 cm from one e~ge and at 37 . 5 cm from the same edge .
The staples provide end points for the narrow reference
lines running between them and will not be affected by
29
WO 96/06685 2 1 9 8 5 9 7 r~
heat, moisture, and h~nrll ;n~. As described below,
meabu~. ~'fi are taken along these reference lines.
4. Place the sample in the center of a piece
of stainless screen with l/4 " grid spacing with the
5 face yarn against the screen and the backing with the
reference lines facing up.
5. Submerge the sample on the screen in a
circulating water bath heated to 40C for at least 48
hours. This defines the ~wet~ condition of the sample
0 which is considered to be 1009~ RH.
6. Remove the sample from the bath by lifting
the screen without disturbing the sample and allow the
sample to drain for about 20-30 minutes until the water
stops dripping rrom the sample.
7. Measure the distance between the staples in
the T/SD and XD with a millimeter scale and record the
values to the nearest 0 . 05 millimeter.
8. Place the sample on the screen in an oven
heated to 40C and positioned to allow air to circulate
2 0 around the top, sides, and bottom of the sample . Close
the oven door and purge the oven with a continuous flow
of low presqllre nitrogen and vent the oven.
9. Monitor the oven humidity with a hydrometer
placed in the bottom of the oven and record when the
2, oven humidity is 3% RH or less. This defi~les the "dry"
condition of the sample which is considered to be 3g~ RH
or less.
10. ~old the sample in the oven for at least
24 hours with the humidity m~in~lnPd at 3~ RH or less.
11. Remove the sample ~rom the oven by lifting
the screen without disturbing the sample and rapidly
measure the distance between the staples in the T/SD
and XD with a millimeter scale and record the values to
the nearest 0 . 05 millimeter.
12. Calculate the percent dimension change in
both the T/SD and XD by subtracting the wet dimension
from the dry ~ qinn and dividing by tlle wet
dimens ion .
`2 1 9 ~ 5 9 7 sgs/l0728
Wo 96/06685 PCT/U
13. Collect the data from at least 5 samples
and average the percent changes to obtain an average
change in the T/SD and an average ~ change in the XD.
All 5 samples may be placed in the water bath
and oven at the same time and the data collected on all
samples at the same time if the bath and oven will hold
the samples spaced apart without disturbing one
another. A rack to support the screens may be used to
support 6 samples at a time in both the water bath and
the oven. When removing samples from the oven, only
one sample at a time would be removed and measured.
A variety of ovens and hydrorneters may be used.
The oven used for the 6 samples labeled single-cycle
data was a VWR Scientific oven model 1450 DS, catalog
#52201-650. The hydrometer used to monitor humidity in
the oven was an Air~uide hydrometer obtained from VWR
Scientific, catalog #35521-087 which has a stated
accuracy of +/- 1-3~s R~I.
1~:
In Test B, steps 1-13 as described above in
Test A are used with the following modifications.
In step #8, the oven is not initially purged
with nitrogen and the humidïty is only reduced to about
14~ R~. The samples are then placed in plastic bags
and transferred to a second oven. The samples are
removed from the plastic bags and placed in the second
oven. This oven is purged with nitrogen and the oven
humidity is reduc~d to 39~ R~l or less. The samples are
held in this oven for at least 24 hours with the
humidity m~1n~;nPd at 39~ RH or less.
. I.L ol Feed Yarn sull;
Yarn bulk was measured using the method
~5 described in Rr-h1ncrn & Thompson, U.S. ~atent
4, 295, 252, the disclosure of which is hereby
incorporated by reference. The yarn bulk levels are
reported herein as ~ bulk crimp elongation (~BC~) as
31
Wo 96/06685 2 1 9 8 5 9 7 PCT/US95/10728
described in Robinson & Thompson. The bulk
measurements were made at 11 m/min for 1. 5 minutes
using a sample length of 16 . 5 meters . The tensioning
weight used was 0.1 gram/denier (O.llg/dtex). The
5 pressure of the air in the heat-setting chamber was
0 . 05 inches of water, and the temperature of the
heating air was 170 +/-30C.
MPLP!.q
Nylon 5'11ftstrin~ rpet ~'An~trUction
In below Table II, the tuftstring carpet
samples were cut from a tuftstring carpet having
solution-dyed nylon 6, 6 face yarn which was fusion-
5 bonded using about 48 watts/strand of ultrasonic energyto a nylon 6,6 support strand reinforced with glass
fibers. The nylon 6, 6 face yarn was made from two yarn
strands of 1235 denier moss green, solutio.~ dyed,
commercial grade (DSDN) yarn, available from DuPont,
20 that were ply-twisted and heat-set with a twist level
of about 4 tpi and a total denier of about 3100. The
~nf~nt singles yarns of the ply-twisted yarn had a
BCE~ of about 31 and a dpf of about 19. The support
strand had a denier of 3900 and a glass-to-nylon ratio
25 of .13. The nylon 6,6 face yarn was placed on the
strand at a density of 12 tuft pairs per inch and cut
to form a . 5 inch pile height . The tuftstrings were
fusion-bonded using ultrasonic energy to a nylon 6, 6
SontaraS and glass fiber laminate comprising a top
30 layer of 1 oz/yd2 of nylon 6,6 SontaraS, a middle layer
of fiberglass scrinl of 6 strands per inch in the MD
having a strength/strand of 8 lbs. and 10 strands per
inch in the XD having a strength/strand of 16 lbs
coated with an acrylic adhesive ! and a bottom layer of
35 1 oz/yd2 of nylon 6, 6 SontaraS.
The tuftstrings were attached at a density of 5
strands per inch to pro~/ide a carpet with a yarn face
~eight of about 25 oz/yd2 u~ing ultrasonic energ~ oL ~3
32
WO 96/06685 2 1 ~ 8 5 9 7 PCJ/USgS/10728
watts/tuftstring. The tuftstrings and carpet were
formed on a tuftstring forming module and belt module
at a speed of a~out lO ypm as described in co-pending,
co-assigned, U. S . Patent Application entitled "Method
5 and Apparatus for Making a Tuftstring Carpet~, the
disclosure of which is hereby incorporated by
ref erence .
In the tuftstring forming module, the face yarn
is wrapped over four strands on a square mandrel and
0 passed under tWG ultrasonic horns; two strands at a
time are bonded to the yarn by a singla ultrasonic horn
engaging two corners of the mandrel. The yarn is cut
between strands while still on the mandrel and the f our
tuftstrings thus formed are directed to a belt forming
5 module which cnnt~inq a loop of backing substrate
driven by a plurality of rolls. The four tuftstrings
are guided under an ultrasonic horn positioned over one
of the rolls, with the horn having four forks engaging
each tuftstring to fusion bond the four tuftstrings to
20 the backing at one time. A second horn following the
first provides additional bonding energy. The four
tuftstrings are LL~LVe~ed along the bonding roll to
spirally wrap the tuftstrings on the backing to form a
three foot wide carpet sample twelve feet long. The
25 carpet sample loop is cut from the rolls and the test
samples are cut from this carpet sample.
Since the nylon 6, 6 face yarn was solution-
dyed, and no latex was used in the assembly, the carpet
was not subject to heat during assembly and was
30 tnerefore not bulked. To bulk the carpet, a separate
bulking process was u~ed as described in the referenced
co-pending, co-assigned U. S . Provisional Patent
Application entitled "Method for Bulking Tuftstring
Carpets~. In this process, the face yarn was heated in
35 a tenter frame with a rapidly flowing stream of hot air
and cooled before release from the tenter pins.
Nylon tuftstring carpet Samples 1-6 were tested
for moisture stability, using the procedures descri}:~ed
33
W096/06685 2 1 9 8 5 9 7 ~ Jli~/~o
in Test A above, and the results are reported below in
Table II. The average length ~ change was 2% or less
which indicates this carpet structure is a moisture
stable tuftstring carpet assembly.
PolypropylPnP Tllfts~ r;ns7 ~'~r~et r~n~tructi~n
In below Table III, the tuftstring carpet
samples were cut from a tuftstring carpet having
polypropylene face yarn which was solution-dyed and
10 fusion-bonded using ultrasonic energy to a
polypropylene support strand comprising a polypropylene
monof ilament . The polypropylene f ace yarn was made
from two 1200 denier, bulked, continuous filament yarn
strands that were ply-twisted and heat-set with a twist
level of 3 . 75 tpi and a total denier of 2400 . The
support strand was a polypropylene monofilament having
an oval cross-section with dimensions of 0 . 035 x 0 . 050
inches and a denier of 6765. The polypropylene face
yarn was placed on the strand at a density of 11 tuft
20 pairs per inch and cut to form a 0.5-inch pile height.
The ultrasonic horn bonding energy for making the
polypropylene tuftstring was about 28 watts. The
tuftstrings were fusion bonded, using ultrasonic energy
of 36 watts, to a two-layered woven polypropylene slit
25 film backing, each layer having a weight of 10.4 g/ft2.
The tuftstrings were attached at a density of 7
strands per inch to provide a carpet with a yarn f ace
weight of about 25 oz/yd2. The tuftstrings and carpet
were formed on the device as illustrated in Figure 3 at
3 0 a spe:~d of about 2 ypm . Since the polypropylene f ace
yarn was solution-dyed and no latex was used in the
assembly, the carpet was not subj ect to heat during
assembly and was therefore not bulked. Bulking was
achieved by blowing hot air having a temperature of
35 about 95C on the tuftstring carpet immediately after
bonding of the elongated pile article to the backing
substrate on the drum.
34
-
Wo96/0668s 2~1 985q7 ~ J~
Polypropylene tuftstring carpet Samples 1-5
were tested for moisture stability, using the
procedures described in Test B above, and the results
are reported below ln Table III. The average length
5 change was 2% o~ less which indicates this carpet
structure is a moisture stable tuftstring carpet
assembly .
Polyester Tn~t~trin~ t~Rrpet rr~n~truct~ on
In below Table IV, the tuftstring carpet
samples were cut from a tuftstrirlg carpet having
polyester (polyethylene ter~rhthi~l Rte) face yarn and
fusion bonded using ultrasonic energy to a polyester
support strand having a sheath of polyester and a core
15 of glass f;l t~. The polyester face yarn was made
from two bulked staple yarn strands that were ply-
twisted and heat-set with a twist level of about 4 tpi
and a total denier of about 4357. The support strand
had a glass f;li ' core of 300 denier covered with a
20 polyester sheath for a total denier of 4536. The
polyester face yarn ~as placed on the strand at a
density of 12 tuft pairs per inch and was cut to form a
0 . 5 inch pile height . The ultrasonic horn bonding
energy for fusion bonding the face yarn to the strand
25 to form the polyester tuftstring was about 25 watts.
The tuftstrings were fusion bonded, using ultrasonic
energy of about 50 watts, to a two layer backing
substrate made from a bottom layer of polyester
5pl~nhnn~Pd sheet havir!g a basis weight of 9 . 35
30 g~ams/ft2 and a top layer of polyester/glass nonwoven
sheet having a basis weight of 23.54 grams/ft2. The
top layer, which is in contact with the tuftstrings,
consists of 25~ glass staple fi~er~ havirlg lengths of
0 . 5 inches and diameters of 13 microns, that are well
35 dispersed in the plane of t~le sheet; and 75% polyester
globules adhered to the glass f ibers . This top sheet
is described in U. S . Patent 5 ,134, 016, the disclosure
of which is hereby incorporated by reference. The two
W0 96/06685 ~ 9 8 5 ~ 7 ~ ,J5,~
layers in the backing are fusion bonded together and to
the tuftstring in one step. Using only this particular
bottom l..yer, there were problems with ultrasonic
bonding .
The tuftstrings we~ e attached at a density of 5
strands per inch to provide a carpet with a yarn face
weight of about 34 oz/yd2. The tuftstrings and carpet
were formed on the device as illustrated in Fig. 3 at a
speed of about 2 ypm. The carpet was not bulked be,fore
0 testing. The polyester tuftstring carpet samples 1-6
were tested for moisture stability, using the
procedures described in Test A above, and the results
are reported below in Table IV. The average length ~6
change was 2~ or less which indicates this carpet
structure is a moisture stable tuftstring carpet
assembly .
Nylon Tl~ftstri~ OA~p~t with Separate ~nn~;n,~ h~ive
In below Table V, a single tuftstring carp2t
sample was made having nylon 6,6 face yarn which was
solution dyed and fusion bonded using ultrasonic energy
to a support strand having a nylon 6, 6 sheath and a
fiberglass filament core as described in the examples
of Table II, The tuftstrings were attached to a
backing substrate using a separate adhesive placed
between the tuftstrings and backing. Tlle backing
substrate was the same as that used in the examples of
Table I~. The separate adhesive was a single layer of
Cytex Fl~S 73M epoxy f ilm having a basis weight of . 03
pounds/ft2.
The tuftstrings were attached to the backillg
substrate at a density of 5 strands per inch in a
special fixture to pro-~ide a carpet sample about 13
inches s~uare with a yarn face weight of about 25
oz/ft2. The fixture consisted of a picture frame
structure which held slats i~l an equally spaced
parallel array of 5 slats/inch. The slats were about
4 inches long, . 12 cm wide and 1 . 25 inches hiyh.
36
wo 96/06685 ~ 'l 9 ~ 5 q 7 PCrmS9S/10728
Thirteen irlch lengths of tuftstrings were cut and
placed on the slats of the fixture such that the tuft
pairs were tucked down between the slats and the strand
rested directly on the edge of a slat. In this way,
5 the base of the tuftstrings were presented upward for
placement of the adhesive layer and the backing
substrate. "Kapton" tape was used at the ends of the
frame to hold the tuftstrings in place. The adhesi~Te
layer was cut to cover the bases of all the tuftstrings
10 and the backing substrate was cut to fit over the
adhesive layer. The frame was then inverted to place
the backing substrate down and it was placed between
two 1/4 inch ~1llminllm plates that were slightly larger
than the f ixture . This assem~ly was then placed in a
5 standard convection oven with a 50 pouïnd weight placed
on the top plate. The temperature in the oven was
ramped from room temperature to 120C in 30 minutes,
and then held at 120C for 1 hour. The oven was turned
off and the sample was allowed to cool in the oven for
20 about 2 hours under the pressure of the 50 pound
weight, then the sample was removed from the fixture.
These nylon tuftstring carpet samples were
tested _or moisture stability according to the
procedure of Test A above with the exception that the
initial mark., on the carpet were 30 cm apart. The
results are repor,ed below in Table v and show that the
averaye length ~ change was 29~ or less which indicates
this carpet structure is a moisture stable tuftstring
carpet assembly.
37
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