U.S. patent application number 10/170276 was filed with the patent office on 2002-12-19 for hot melt adhesive composition.
Invention is credited to Daily, Jeffrey Daniel, Van Scoy, Shannon Lee.
Application Number | 20020193474 10/170276 |
Document ID | / |
Family ID | 26865913 |
Filed Date | 2002-12-19 |
United States Patent
Application |
20020193474 |
Kind Code |
A1 |
Daily, Jeffrey Daniel ; et
al. |
December 19, 2002 |
Hot melt adhesive composition
Abstract
A hot melt adhesive that is useful in the production of
textiles, such as a tuft carpet, contains a blend of constituents
that allows synthetic carpet members to be fully recycled without
first separating the adhesive from the carpet members. The adhesive
includes: a) from about 5 to about 30 weight % of a copolymer of an
alkyl acrylate having from 2 to 18 carbon atoms; b) from about 5 to
about 50 weight % of a wax and desirably a C10 wax; c) up to about
75 weight % of a filler; and d) from about 0.1 to about 10 weight %
of an aliphatic carboxylic acid having from 8 to 24 carbon
atoms.
Inventors: |
Daily, Jeffrey Daniel;
(Hallsville, TX) ; Van Scoy, Shannon Lee;
(Chatsworth, GA) |
Correspondence
Address: |
Mark L. Davis
P.O. Box 9293
Gray
TN
37615-9293
US
|
Family ID: |
26865913 |
Appl. No.: |
10/170276 |
Filed: |
June 12, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60298194 |
Jun 14, 2001 |
|
|
|
Current U.S.
Class: |
524/109 ;
524/284; 524/423; 524/425; 524/487; 524/558 |
Current CPC
Class: |
C09J 133/06 20130101;
Y10T 428/23993 20150401; Y10T 428/31765 20150401; Y10S 526/935
20130101; C08L 2666/28 20130101; C09J 133/06 20130101; C08L 91/06
20130101; C08L 2666/26 20130101; C08L 2666/28 20130101; Y10S
524/915 20130101; C08L 2666/54 20130101; C08L 2666/54 20130101;
Y10T 428/28 20150115; C08L 2666/26 20130101; Y10T 428/2891
20150115; Y10T 428/31855 20150401 |
Class at
Publication: |
524/109 ;
524/284; 524/487; 524/558; 524/423; 524/425 |
International
Class: |
C08J 003/00 |
Claims
We claim:
1. A hot melt adhesive composition, comprising: a) from about 5 to
about 30 weight % of at least one copolymer of an alkyl acrylate
having from 2 to 18 carbon atoms; b) from about 5 to about 50
weight % of a wax; c) up to about 75 weight % of a filler; and d)
from about 0.1 to about 10 weight % of an aliphatic carboxylic acid
having from 8 to 32 carbon atoms.
2. The adhesive of claim 1 wherein said alkyl acrylate is selected
from the group consisting of ethylene (meth)acrylate, methyl
(meth)acrylate, propyl acrylate, butyl (meth)acrylate, hexyl
acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, lauryl acrylate,
stearyl acrylate and mixtures thereof.
3. The adhesive of claim 1 wherein said alkyl acrylate is selected
from the group consisting of ethylene (meth)acrylate and ethylene
n-butyl (meth)acrylate.
4. The adhesive of claim 1 wherein said wax is selected from the
group consisting of paraffin waxes, microcrystalline waxes, high
density low molecular weight polyethylene waxes, by-product
polyethylene waxes, Fischer-Tropsch waxes, oxidized Fischer Tropsch
waxes, hydroxy waxes, stearamide waxes and mixtures thereof.
5. The adhesive of claim 1 wherein said wax has from 6 to 20 carbon
atoms.
6. The adhesive of claim 1 wherein said wax has from 6 to 15 carbon
atoms.
7. The adhesive of claim 1 wherein said wax has from 8 to 10 carbon
atoms.
8. The adhesive of claim 1 wherein said aliphatic carboxylic acid
is from about 1 to about 5 weight % and has from 12 to 18 carbon
atoms.
9. The adhesive of claim 8 wherein said aliphatic carboxylic acid
is stearic acid.
10. The adhesive of claim 1 wherein said filler is selected from
the group consisting of calcium carbonate, magnesium carbonate,
calcium sulfate, barium sulfate, silica, fly ash, and mixtures
thereof.
11. The adhesive of claim 1 further comprising at least one
constituent selected from the group an antioxidant, a plasticizer,
a tackifier, and a flame retardant.
12. A hot melt adhesive composition, comprising: a) from about 5 to
about 30 weight % of at least one copolymer of an alkyl acrylate
selected from the group consisting of methyl acrylate, ethylene
(meth)acrylate, propyl acrylate, butyl (meth)acrylate, hexyl
acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, lauryl acrylate,
stearyl acrylate and mixtures thereof; b) from about 5 to about 50
weight % of a wax having from 6 to 20 carbon atoms; c) up to about
75 weight % of a filler; and d) from about 0.1 to about 10 weight %
of an aliphatic carboxylic acid having from 8 to 32 carbon
atoms.
13. The hot melt adhesive composition of claim 12 wherein said
alkyl acrylate is an ethylene (meth)acrylate.
14. The hot melt adhesive composition of claim 12 wherein said wax
is selected from the group consisting of paraffin waxes,
microcrystalline waxes, high density low molecular weight
polyethylene waxes, by-product polyethylene waxes, Fischer-Tropsch
waxes, oxidized Fischer Tropsch waxes, hydroxy waxes, stearamide
waxes and mixtures thereof.
15. The hot melt adhesive composition of claim 12 wherein said
filler is selected from the group consisting of calcium carbonate,
clay, magnesium carbonate, calcium sulfate, alumina, talc, barium
sulfate, silica, carbon black, aluminum hydroxide, magnesium
hydroxide and mixtures thereof.
16. The hot melt adhesive composition of claim 12 wherein said
filler is from about 15 to about 70 weight % of the
composition.
17. The hot melt adhesive composition of claim 12 wherein said
filler is from about 25 to 65 weight % of the composition.
18. The hot melt adhesive composition of claim 12 wherein said
carboxylic acid has from 12 to 18 carbon atoms.
19. The hot melt adhesive composition of claim 12 further
comprising at least one of an antioxidant, a plasticizer, a
tackifier, a flame retardant, and a colorant.
20. The hot melt adhesive composition of claim 19 wherein said
antioxidant is selected from the group consisting of
1,3,5-trimethyl 2,4,6-tris
(3,5-di-tert-butyl-4-hydroxybenzyl)benzene; pentaerythrityl
tetrakis-3(3,5-di-tert-butyl-4-hydroxyphenyl)propionate;
n-octadecyl-3(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate;
4,4'-methylenebis(2,6-tert-butylphenol);
4,4'-thiobis(6-tert-butyl-o-cres- ol); 2,6-di-tertbutylphenol;
6-(4-hydroxyphenoxy)-2,4-bis(n-octyl-thio)-1,- 3,5 triazine;
di-n-octylthio)ethyl 3,5-di-tert-butyl-4-hydroxy-benzoate; and
sorbitol
hexa(3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate).
21. The hot melt adhesive composition of claim 19 wherein said
plasticizer is selected from the group consisting of
2-ethylhexanol, cyclohexanol, phenol, naphthol, 1,2-benzene
dicarboxylic acid, 1,3-benzene dicarboxylic acid (isophthalic
acid), 1,4-benzene dicarboxylic acid (terephthalic acid), dioctyl
phthalate, butyl benzyl phthalate, dicyclohexyl phthalate, diphenyl
phthalate, ethylene glycol, propylene glycol, 1,2-butylene glycol,
1,4-butylene glycol, glycerine, glucose, fructose, sucrose,
mannitol, trimethylolethane, 1,4-cyclohexanedimethanol,
pentaerythritol, 2,2-dimethyl-1,3-propanediol,
2-hydroxymethyl-2-methyl-1,3-propanediol, neopentyl glycol,
ethylene glycol dibenzoate, propylene glycol dibenzoate,
trimethylene glycol tribenzoate, trimethylol ethane tribenzoate,
glycerol tribenzoate, sucrose benzoate, pentaerythritol
tetrabenzoate, 2,2-dimethyl-1,3-propanediol dibenzoate,
trimethylene glycol dibenzoate, glycerol tribenzoate,
2-hydroxymethyl-2-methyl-1,3-pro-
panedioltribenzoatepentaerythritoltetraben zoate, neopentyl glycol
dibenzoate and mixtures of these plasticizers.
22. A multi-layer laminated article comprising: a. a first layer
selected from the group consisting of polypropylene and polyamides;
and b. a second layer comprising a hot melt adhesive composition,
comprising: i) from about 5 to about 30 weight % of at least one
copolymer of an alkyl acrylate selected from the group consisting
of methyl acrylate, ethylene (meth)acrylate, propyl acrylate, butyl
(meth)acrylate, hexyl acrylate, 2-ethylhexyl acrylate, dodecyl
acrylate, lauryl acrylate, stearyl acrylate and mixtures thereof;
ii) from about 5 to about 50 weight % of a wax having from 6 to 20
carbon atoms; iii) up to about 75 weight % of a filler; and iv)
from about 0.1 to about 10 weight % of an aliphatic carboxylic acid
having from 8 to 32 carbon atoms.
23. The multi-layer laminated article of claim 22 wherein said wax
is selected from the group consisting of paraffin waxes,
microcrystalline waxes, high density low molecular weight
polyethylene waxes, by-product polyethylene waxes, Fischer-Tropsch
waxes, oxidized Fischer Tropsch waxes, hydroxy waxes, stearamide
waxes and mixtures thereof.
24. The multi-layer laminated article of claim 23 wherein said
filler is from about 25 to 65 weight % of the composition and is
selected from the group consisting of calcium carbonate, clay,
magnesium carbonate, calcium sulfate, alumina, talc, barium
sulfate, silica, carbon black, aluminum hydroxide, magnesium
hydroxide and mixtures thereof.
25. The multi-layer laminated article of claim 22 wherein said
carboxylic acid has from 12 to 18 carbon atoms.
26. A recyclable carpet composition comprising: a. a first layer
selected from the group consisting of polypropylene and polyamides;
and b. a second layer comprising a hot melt adhesive composition,
comprising: i) from about 5 to about 30 weight % of at least one
copolymer of an alkyl acrylate selected from the group consisting
of methyl acrylate, ethylene (meth)acrylate, propyl acrylate, butyl
(meth)acrylate, hexyl acrylate, 2-ethylhexyl acrylate, dodecyl
acrylate, lauryl acrylate, stearyl acrylate and mixtures thereof;
ii) from about 5 to about 50 weight % of a wax having from 6 to 20
carbon atoms; iii) up to about 75 weight % of a filler; and iv)
from about 0.1 to about 10 weight % of an aliphatic carboxylic acid
having from 8 to 32 carbon atoms.
27. The recyclable carpet composition of claim 26 wherein said wax
is selected from the group consisting of high density low molecular
weight polyethylene waxes, and by-product polyethylene waxes having
from 6 to 15 carbon atoms, from about 25 to 65 weight % filler, and
said aliphatic carboxylic acid is from about 1 to about 5 weight %
stearic acid.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] Benefit is claimed to the earlier filed application having
U.S. Ser. No. 60/298,194 filed Jun. 14, 2001, the entire disclosure
of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a hot melt adhesive
composition that is useful in laminating together two or more
layers in the preparation of a carpet. More particularly, the
present invention relates to a hot melt adhesive composition that
may be used in the construction of a multi-layered synthetic carpet
that provides for 100% recycling of the carpet.
[0004] 2. Background of the Invention
[0005] Hot melt adhesives which are heated to substantially
softened and preferably molten state, which are then applied to a
substrate and allowed to cool and harden are widely used for
industrial purposes. For example, such hot melt adhesives have been
used in the manufacture of textiles, such as carpets, personal care
products, such as diapers and adult incontinence products in the
automobile industry such as bonding headliners
[0006] In the area of textiles, and particularly for the
manufacture of carpets, it is becoming increasingly important to
recycle the carpet trimmings and rejected materials to reduce the
amount of waste that presently has to be disposed of in landfills
and to improve the manufacturing economics.
[0007] Although the utility of the present adhesive composition
will be described as it relates to a carpet textile one skilled in
the art will understand that the adhesive composition of the
present invention may be used in other applications where recycling
of the material is of importance.
[0008] Manufacture of tufted pile carpets normally involves tufting
a primary backing followed by washing, dying and drying the tufted
backing and then subjecting the same to a finishing operation in
which a secondary backing is laminated to a backside of the tufted
primary backing.
[0009] Tufting usually is accomplished by inserting reciprocating
needles threaded with yarn into the primary backing to form tufts
of yarn. Loopers or hooks, typically working in timed relationship
with the needles, are located such that the loopers are positioned
just above the needle eye when the needles are at an extreme point
in their stroke through the backing fabric. When the needles reach
that point, yarn is picked up from the needles by the loopers and
held briefly. Loops or tufts of yarn result from passage of the
needles back through the primary backing. This process typically is
repeated as the loops move away from the loopers due to advancement
of the backing through the needling apparatus.
[0010] If desired, the loops can be cut to form a cut pile, for
example, by using a looper and knife combination in the tufting
process to cut the loops. Alternatively, the loops can remain
uncut.
[0011] Primary backings for tufted pile carpets are typically woven
or nonwoven fabrics made of one or more natural or synthetic fibers
or yarns, such as jute, wool, polypropylene, polyethylene,
polyamides, polyesters, and rayon. Films of synthetic materials,
such as polypropylene, polyethylene and ethylene-propylene
copolymers also can be used to form the primary backing.
[0012] The tufts of yarn inserted in the tufting process are
usually held in place by untwisting of the yarn as well as
shrinkage of the backing. In the finishing operation, the backside
or stitched surface of the backing usually is coated with an
adhesive, also commonly referred to as a backcoat, such as a
natural or synthetic rubber or resin latex or emulsion or a hot
melt adhesive, to enhance locking or anchoring of tufts to the
backing. Use of such backcoats also improves dimensional stability
of the tufted carpet, resulting in more durable carpets of improved
skid and slip resistance.
[0013] Generally, the tufted carpet is further stabilized in the
finishing operation by laminating a secondary backing, for example
a thermoplastic film or a woven or nonwoven fabric made from
polypropylene, polyethylene, or ethylene-propylene copolymers or
natural fibers such as jute, to the tufted primary backing. The
adhesive used in the finishing operation bonds the primary backing
to the secondary backing.
[0014] In carpet lamination processes, basic requirements for
adhesives include ability to bond strongly to the primary backing
and bond to the tuft stitches protruding through its backside and
the secondary backing. In particular, ability to adhere to nylon
and polypropylene is important because the combination of these
materials (polypropylene backing fabrics and nylon face yarns)
accounts for a large percentage of carpet manufactured at present.
Activation temperature of a hot melt adhesive, that is, temperature
at which the adhesive softens and flows sufficiently to wet and
penetrate the backing surfaces and tuft stitches, must be below the
temperature at which the backing and face yarns melt or suffer
other damage due to heating, for example, relaxation of oriented
polyolefin yarns in the backings. Adhesives also must have a low
enough viscosity at temperatures employed in finishing to achieve
good wetting of the backings and sufficient encapsulation of tuft
stitches to make the tuft yarns resistant to pull-out, pilling and
fuzzing. In addition, for commercial practice, economics of a
carpet manufacturing process utilizing hot melt adhesive must be at
least as good as those of conventional latex lamination techniques
which remain the dominant lamination process in commercial carpet
manufacture.
[0015] A number of hot melt adhesives and processes using the same
have been proposed for use in carpet lamination. For example, U.S.
Pat. No. 3,583,936 issued to Stahl on Jun. 8, 1971 discloses a hot
melt adhesive having: (1) from about 10-35 weight % ethylene
copolymer having about 60-85 weight % ethylene units and about
40-15 weight % lower vinyl ester, acrylate, or methacrylate units;
(2) about 10-25 weight % of a wax component having a melting point
sufficient to give an adhesive composition with a softening point
greater than 190.degree. F.; and (3) about 50-70 weight % of a
resin extender that is a blend of (a) an aliphatic thermoplastic
hydrocarbon resin that is substantially free of polymerized
aromatics prepared from diene and olefin monomers of 5 to 7 carbon
atoms and (b) a polymer resin derived from the alkylation of
aromatic compounds with dicyclopentadiene and having a softening
point of about 40.degree. F.-105.degree. F.
[0016] U.S. Pat. No. 3,982,051 issued to Taft et al. on Sep. 21,
1976 discloses a hot melt adhesive for carpet lamination having
consisting essentially of: (1) from about 5% to about 50% by weight
of a copolymer of ethylene and unsaturated ester monomer selected
from the group consisting of vinyl acetate; alkyl acrylate wherein
the alkyl group contains 1-18 carbon atoms; and mixtures thereof;
containing from about 40 to 85% by weight of ethylene and from
about 15 to about 60% by weight of unsaturated ester monomer; (2)
from about 10 to about 85% by weight of an atactic polypropylene;
and (3) from about 10 to about 50% of vulcanized rubber, wherein
the composition is based upon the combined weight of (1), (2), and
(3).
[0017] U.S. Pat. No. 3,551,231, issued Dec. 29, 1970 to Smedberg,
discloses a hot melt adhesive carpet lamination process in which
molten adhesive consisting of an ethylene-vinyl acetate copolymer
and, optionally, waxes (e.g. microcrystalline and polyethylene
waxes), fillers (e.g. calcium carbonate), resin extenders (e.g.,
dicyclopentadiene alkylation polymers) and antioxidant is applied
to a tufted primary backing and then a secondary backing is
contacted with the so-applied, molten adhesive under pressure after
which the assembly is cooled to solidify the adhesive.
[0018] U.S. Pat. No. 4,939,036 discloses a hot melt adhesive
composition having about 25 to about 40 weight percent of a
polyethylene having a melt index of about 15 to about 30 grams per
ten minutes; about 25 to about 40 weight percent of a polyterpene
resin having a ring and ball softening point of about 90.degree. to
about 105.degree. C., about 10 to about 20 weight percent of a
paraffin wax having a melting point of about 140.degree. F. to
about 165.degree. F., about 10 to about 20 weight percent
polybutene having a viscosity of about 500 to about 5000
centistokes at 210.degree. F. and up to about 1 weight percent
antioxidant.
[0019] Although the aforementioned hot melt adhesives may be used
for carpet lamination, it is desired in the textile industry to
create products that are 100 percent recyclable with minimum
difficulty. Accordingly, there remains a need for a hot melt
adhesive carpet lamination process that will provide tufted carpets
of good bond strength between primary and secondary backings as
well as allow for the carpet to be recycled without physically
separating the bonding materials before recycling the carpet
material.
SUMMARY OF THE INVENTION
[0020] Surprisingly, it has been found that a hot melt adhesive
based on copolymers of ethylene and methyl acrylate have good heat
resistance while maintaining excellent flexibility and permit the
carpet to be 100% recyclable.
[0021] Briefly, the present invention is a hot melt adhesive having
from about 5 to about 30 weight % of at least one copolymer of an
alkyl acrylate having from 2 to 18 carbon atoms; from about 5 to
about 50 weight % of a wax; up to about 70 weight % of a filler;
and from about 0.1 to about 10 weight % of an aliphatic carboxylic
acid having from 8 to 24 carbon atoms.
[0022] Another aspect of the present invention is a multi-layered
laminated article such as a synthetic carpet having a first layer
comprising polypropylene or a polyamide and a second layer
comprising the adhesive composition above.
DETAILED DESCRIPTION OF THE INVENTION
[0023] Advantageously, the adhesive composition of the present
invention allows 100% of the polymeric product to be recycled and
provides a water-resistant bond. The adhesive composition includes
from about 5 to about 30 weight % of at least one copolymer of an
alkyl acrylate having from 2 to 18 carbon atoms; from about 5 to
about 50 weight % of a wax; up to about 70 weight % of a filler;
and from about 0.1 to about 10 weight % of an aliphatic carboxylic
acid having from 8 to 24 carbon atoms. Desirably, the adhesive
composition includes from about 5 to 20 weight % of a copolymer of
an alkyl acrylate having from 2 to 18 carbon atoms which preferably
is selected from ethylene (meth) acrylate, methyl (meth) acrylate,
propyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl
acrylate, dodecyl acrylate, lauryl acrylate, stearyl acrylate and
mixtures thereof. As used herein, (meth)acrylates includes both
acrylates and methacrylates. Preferably, the adhesive includes from
about 5 to 15 weight % of ethylene and/or methyl (meth)acrylate
copolymer.
[0024] The copolymers of the alkyl acrylates and preferably
ethylene and methyl (meth)acrylate useful herein are those having
from about 10% to about 40% by weight methyl (meth)acrylate,
preferably from about 15% to about 30% by weight, and most
preferably from about 20% to about 30% by weight, and a melt index
of less than about 1500 g/10 min., preferably less than about 1000
g/10 min. and most preferably less than about 500 g/10 min.
Polymers with lower melt indices provide better heat resistance and
better tensile strength provided a low enough viscosity is
maintained. These copolymers are available from Exxon Chemical Co.
under the tradename of OPTEMA. Some available grades are TC-140,
XS-93.04 and TC-221. They are also available from Elf Atochem North
America under the tradename of LOTRYL. Some available grades are 9
MA 02, 14 MG 02, 15 MA 03, 16 MA 003, 18 MA 02, 18 MG 02, 20 MA
08/20 MB 08, 24 MA 005, 28 MA 07, 28 MA 175, 29 MA 03 and 35 MA 05.
Other sources include EMAC available from Eastman Chemical Company.
One such grade is SP 2220X which has 20 weight % methyl acrylate
and a melt index of 20 g/10 min. Even though acrylates are
preferred, methacrylate copolymers are also contemplated for use in
this invention.
[0025] The lower alkyl acrylates may additionally contain from 0 to
about 3 weight % of other polymerizable monomers, such as acrylic
acid, methacrylic acid, itaconic acid, acrylamide, beta
dimethylaminoethyl methacrylate, beta hydroxyethyl acrylate,
diallyl maleate, diallyl phthalate, diallyl ether or ethylene
glycol dimethacrylate.
[0026] The waxes useful in the adhesive composition of the present
invention include waxes having from 6 to 20 carbon atoms,
preferably from 6 to 15 carbon atoms and most preferably from 8 to
carbon atoms. Suitable waxes include paraffin waxes,
microcrystalline waxes, high density low molecular weight
polyethylene waxes, by-product polyethylene waxes, Fischer-Tropsch
waxes, oxidized Fischer-Tropsch waxes, and hydroxy stearamide
waxes. Other functional waxes are available as well as other fatty
amide waxes. It is common in the art to use the terminology
synthetic high melting point waxes which includes high density low
molecular weight polyethylene waxes, by-product polyethylene waxes,
and Fischer-Tropsch waxes.
[0027] The paraffin waxes useful herein are those having a Ring and
Ball softening point of about 55.degree. C. to about 85.degree. C.
The preferred waxes are Okerin..TM.. 236TP available from Astor Wax
Corporation located in Doraville, Ga.; Penreco..TM.. 4913 available
from Pennzoil Products Co. in Houston, Tex.; R-7152 Paraffin Wax
available from Moore & Munger in Shelton, Conn.; and Paraffin
Wax 1297 available from International Waxes, Ltd in Ontario,
Canada.
[0028] The microcrystalline waxes useful herein are those having
about 50% by weight or more cyclo or branched alkanes with a length
of between about 30 and 100 carbons. They are generally less
crystalline than paraffin and polyethylene waxes, and have melting
points of greater than about 70.degree. C. Examples include
Victory..TM.. Amber Wax, a 70.degree. C. melting point wax
available from Petrolite Corp. located in Tulsa, Okla.;
Bareco..TM.. ES-796 Amber Wax, a 70.degree. C. melt point wax
available from Bareco in Chicago, Ill.; Okerin..TM. 177, an
80.degree. C. melt point wax available from Astor Wax Corp.;
Besquare..TM.. 175 Amber Wax, an 80.degree. C. melt point
microcrystalline wax, Be Square..TM.. 195 Amber Wax, a 90.degree.
C. melt point wax all available from Petrolite Corp.;
Indramic..TM.. 91, a 90.degree. C. melt point wax available from
Industrial Raw Materials located in Smethport, Pa.; and
Petrowax..TM.. 9508 Light, a 90.degree. C. melt point wax available
from Petrowax Pa., Inc. located in New York, N.Y.
[0029] The synthetic high melting point waxes useful herein are
high density, low molecular weight polyethylene waxes preferably
having from 6 to 15 carbon atoms, by-product polyethylene waxes and
Fischer-Tropsch waxes. Preferred waxes include EPOLENE C10
available from Eastman Chemical Company, PETROLITE C-4040, POLYWAX
1000, 2000 and 3000, low molecular weight polyethylene waxes
available from Petrolite Corp.; ESCOMER H-101, a modified
polyethylene wax available from Exxon Chemical Co.; Marcus 100, 200
and 300, low molecular weight by-product polyethylene waxes
available from Marcus Chemical Co., a Division of H.R.D. Corp.
located in Houston, Tex.; and PARAFLINT H-1, H-4 and H-8,
Fischer-Tropsch waxes available from Sasol-SA/Moore & Munger in
Shelton, Conn.
[0030] The waxes are useful in amounts from about 5 to about 50
weight %, preferably from about 10 to about 40 weight % and most
preferably from about 15% to about 25 weight % in the adhesive, and
may be used in any combination. One skilled in the art would
recognize that different amounts of a wax will be used depending on
the type of wax and the specific application, and that different
combinations of waxes will also affect the amount of wax
desired
[0031] Fillers which may be used include calcium carbonate, clay,
magnesium carbonate, calcium sulfate, alumina, talc, barium
sulfate, silica, carbon black, aluminum hydroxide, magnesium
hydroxide and other various finely divided organic and other
inorganic materials or fibers, and mixtures of the above, to reduce
cost and increase viscosity of hot melt adhesive. Filler content of
the adhesive composition is used according to this invention can be
varied to achieve compositions of desired viscosity but typically
up to about 75 weight % of the total composition. Preferably, the
filler is from about 15 to about 70 weight % and more preferably
from about 25 to about 65 weight % of the total composition.
[0032] The fourth component of the adhesive is an aliphatic
carboxylic acid having from 8 to 32 carbon atoms and preferably
from 12 to 18 carbon atoms. The amount of aliphatic carboxylic acid
added to the adhesive is from about 0.1 to about 10 weight % of the
total composition, and preferably from about 1 to about 5 weight
%.
[0033] In addition to the above components, the hot melt adhesive
may include up to about 4 weight % of other additives to impart
desired properties. For example, antioxidants, plasticizers,
tackifiers, flame retardants, and colorants. The adhesive
composition may also include a foaming agent capable of releasing a
gas at a temperature above the activation temperature of the
adhesive but below the finishing temperature to reduce the amount
of adhesive necessary for forming the bond.
[0034] Suitable antioxidants include high molecular weight hindered
phenols and multifunctional phenols such as sulfur and
phosphorous-containing phenol. Hindered phenols are well known to
those skilled in the art and may be characterized as phenolic
compounds which also contain sterically bulky radicals in close
proximity to the phenolic hydroxyl group thereof. In particular,
tertiary butyl groups generally are substituted onto the benzene
ring in at least one of the ortho positions relative to the
phenolic hydroxy group. The presence of these sterically bulky
substituted radicals in the vicinity of the hydroxyl group serves
to retard its stretching frequency, and correspondingly, its
reactivity; this hindrance thus providing the phenolic compound
with its stabilizing properties. Representative hindered phenols
include; 1,3,5-trimethyl
2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene;
pentaerythrityl
tetrakis-3(3,5-di-tert-butyl-4-hydroxyphenyl)propionate;
n-octadecyl-3(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate;
4,4'-methylenebis(2,6-tert-butylphenol);
4,4'-thiobis(6-tert-butyl-o-cres- ol); 2,6-di-tertbutylphenol;
6-(4-hydroxyphenoxy)-2,4-bis(n-octyl-thio)-1,- 3,5triazine;
di-n-octylthio)ethyl 3,5-di-tert-butyl-4-hydroxy-benzoate; and
sorbitol
hexa(3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate).
[0035] The performance of these antioxidants may be further
enhanced by utilizing, in conjunction therewith known synergists
such, for example, as thiodipropionate esters and phosphites,
particularly useful is distearylthiodipropionate. These
stabilizers, if used, are generally present in amounts of about 0.1
to 1.5 weight percent, preferably 0.25 to 1.0%. Other additives
such as plasticizers, pigments, dyestuffs conventionally added to
hot melt adhesives for various end uses contemplated as well as
small amounts of additional tackifiers and/or waxes such as
paraffin wax may also be incorporated in minor amounts, i.e., up to
about 10% by weight, into the formulations of the present
invention.
[0036] Plasticizers that may be included in the adhesive of the
invention may be liquid or solid, depending on properties sought.
Solid plasticizers with increased softening points of
(60.degree.-130.degree. C.) can aid in improving heat resistance or
preventing bond failure at high temperatures. One useful class of
plasticizers are cycloaliphatic and/or aromatic ester of a benzene
dicarboxylic acid. Such plasticizers are prepared by forming an
ester from an aliphatic or aromatic alcohol, or mixtures of such
alcohols, such as 2-ethylhexanol, cyclohexanol, phenol, naphthol,
or other monohydroxy alcohol compounds having from 5 to 12 carbon
atoms. The ester compounds are formed from dicarboxylic acid
compounds, typically phthalic acids. Phthalic acids that can be
used in the plasticizers are 1,2-benzene dicarboxylic acid,
1,3-benzene dicarboxylic acid (isophthalic acid), or 1,4-benzene
dicarboxylic acid (terephthalic acid). Such plasticizers of this
class include dioctyl phthalate, butyl benzyl phthalate,
dicyclohexyl phthalate and diphenyl phthalate.
[0037] Other suitable plasticizers include an aromatic carboxylic
acid ester of a polyfunctional alcohol having 2 to 10 hydroxyl
groups. Polyfunctional alcohols that can be used in the
compositions of this class of plasticizers include compounds having
at least two hydroxyl groups and at least two carbon atoms in the
molecule. Specific examples of preferred hydroxy compounds include
ethylene glycol, propylene glycol, 1,2-butylene glycol,
1,4-butylene glycol, glycerine, glucose, fructose, sucrose,
mannitol, trimethylolethane, 1,4-cyclohexanedimethanol,
pentaerythritol, 2,2-dimethyl-1,3-propanediol,
2-hydroxymethyl-2-methyl-1- ,3-propanediol, neopentyl glycol, and
other useful polyfunctional hydroxyl compounds. Aromatic acids that
can be used with the polyfunctional alcohols to form this class of
ester plasticizer compounds include aromatic carboxylic acids,
typically having at least one aromatic group and at least one
carboxyl function. Representative acids include benzoic acid,
naphthionic acid, and 4-methyl benzoic acid. Typical examples of
such useful plasticizers include ethylene glycol dibenzoate,
propylene glycol dibenzoate, trimethylene glycol tribenzoate,
trimethylol ethane tribenzoate, glycerol tribenzoate, sucrose
benzoate, pentaerythritol tetrabenzoate,
2,2-dimethyl-1,3-propanediol dibenzoate, trimethylene glycol
dibenzoate, glycerol tribenzoate, 2-hydroxymethyl-2-methyl-1,3-pro-
panedioltribenzoatepentaerythritoltetraben zoate, neopentyl glycol
dibenzoate, mixtures thereof, and others. A preferred plasticizer
is a solid with a softening point above 60.degree. C. which belongs
to the class of plasticizers including cyclohexane dimethanol
dibenzoate compounds. A 1,4-cyclohexane dimethanol dibenzoate
(containing cis- and trans-isomers) is exemplified and produces the
maximum control over variation and change in adhesive physical
properties.
[0038] Tackifiers that may be added to the adhesive composition may
be rosin derivatives (including wood rosin, tall oil, tall oil
derivatives, rosin ester rosins, etc.), aliphatic resins such as
natural and synthetic terpenes and aromatic or mixed
aromatic-aliphatic tackifying resins.
[0039] Representative examples of rosin include gum rosin, wood
rosin, and tall oil rosin. Representative examples of rosin
derivative tackifying resins include the pentaerythritol esters of
tall oil, gum rosin, wood rosin and mixtures thereof.
[0040] Aliphatic monomers are typically natural and synthetic
terpenes which contain C.sub.5 and C.sub.6 cyclohexyl or
cyclopentyl saturated groups that can additionally contain a
variety of substantially aliphatic ring substituents. Aliphatic
tackifying resins can be made by polymerizing a feed stream
containing sufficient aliphatic monomer such that the resulting
resin exhibits aliphatic characteristics. Such feed streams can
contain other aliphatic unsaturated monomers such as 1,3-butadiene,
cis-1,3-pentadiene, trans-1,3-pentadiene, 2-methyl-1,3-butadiene,
2-methyl-2-butene, cyclopentadiene, dicyclopentadiene, terpene
monomers, and others. Mixed aliphatic-aromatic resins contain
sufficient aromatic monomers and sufficient aliphatic monomers and
optionally other C.sub.3-C.sub.8 unsaturated monomers to produce a
resin having both aliphatic and aromatic character.
[0041] Specific examples of other tackifying resins which may be
employed in the formulations of the invention include EASTOTAC
H-100, H-115 and H-130 from Eastman Chemical Co. in Kingsport,
Tenn. which are partially hydrogenated cycloaliphatic petroleum
hydrocarbon resins with different softening points. These are
available in E grade, R grade, L grade and W grade. These have
differing levels of hydrogenation from least hydrogenated (E) to
most hydrogenated (W). The E grade has a bromine number of 15, the
R grade a bromine number of 5, the L grade has a bromine number of
3 and the W grade a bromine number of 1. There is also an EASTOTAC
H-142R resin available. Other useful tackifying resins include
ESCOREZ 5300 and ESCOREZ 5400, partially hydrogenated
cycloaliphatic petroleum hydrocarbon resins, and ESCOREZ 5600, a
partially hydrogenated aromatic modified petroleum hydrocarbon
resin all available from Exxon Chemical Co. in Houston, Tex.;
WINGTACK Extra which is an aliphatic, aromatic petroleum
hydrocarbon resin available from Goodyear Chemical Co. in Akron,
Ohio; HERCOLITE 2100 which is a partially hydrogenated
cycloaliphatic petroleum hydrocarbon resin available from Hercules
in Wilmington, Del.; and ZONATAC 105 Lite which is a styrenated
terpene resin made from d-limonene and available from Arizona
Chemical Co. in Panama City, Fla.
[0042] The composition in accordance with the present invention may
be blended with a mixer such as a kneader, Brabender mixer, Banbury
mixer, and a single or double screw extruder. The blending with the
mixer may be conducted by adding thereto each compound component.
The order of adding the components to the mixer is not restricted.
Generally, no external heat is required to be added to the mixture
and only the heat from mixing is used to blend the components. The
heating temperature may range from 100.degree. to 200.degree. C.
and preferably is from 110.degree. to 180.degree. C., and a period
of time required for the blending may range from 5 to about 40
minutes and preferably from 8 to 30 minutes, whereby a sufficiently
homogeneous mixture can be obtained.
[0043] The resultant composition may then be extruded and formed
into powders, pellets, film, sheets and the like. The adhesive
composition in the form of pellets may be applied to the carpet
backing by first extruding the pellets with an extruder or the like
into a sheet or a film, so that it may then be backed by laminating
the sheet or the film onto the carpet base material with an
adhesive or by heating.
[0044] Alternatively, the composition may be extruded immediately
after blending in the form of a film or a sheet directly onto the
carpet base material thereby being processed directly to back the
carpet base material.
[0045] Typically, in applying the adhesive to a carpet backing, the
substrate and composite hot melt adhesive are heated in contact to
activate the adhesive with application of pressure sufficient to
press the backing surfaces into the activated adhesive and cause
tuft stitch encapsulation. Heating is at a temperature at least
equal to that at which the adhesive composition activate but below
the temperature at which the backings and face yams suffer damage,
e.g., melting or loss of orientation, due to heating. With
polypropylene backings and face yarns of polypropylene or higher
melting yarns such as polyamides (Nylon), heating preferably is at
a temperature such that the interior of the carpet structure does
not exceed about 300.degree. F. (about 150.degree. C.). More
preferably, interior temperatures during lamination range from
about 240.degree. F. to about 290.degree. F. (116.degree.
C.-144.degree. C.).
[0046] Application rates of the hot melt adhesive are sufficient to
provide good encapsulation and strength without waste of the
adhesive or oozing thereof through the primary backing and into the
face yarns protruding from the face surface of the backing. Precise
application rates can vary considerably depending on carpet style.
For carpet styles which are roughly representative of the middle of
the spectrum of carpet styles in terms of stitch density, face yarn
and backing characteristics, about 1/2 to about 4 pounds (0.227
kg/m.sup.2 to about 1.8 kg/m.sup.2) of adhesive is applied per
square yard of carpet (lbs/yd.sup.2). Acceptable results with such
carpet types are achieved at application rates of about 0.8 to
about 3 lbs/yd.sup.2 (0.3 kg/m.sup.2 to about 1.1 kg/m.sup.2). Most
preferably about 0.8 to about 1.5 lbs/yd.sup.2 (0.3 kg/m.sup.2 to
about 0.6 kg/m.sup.2).
[0047] Pressure is applied to press the backings into the activated
adhesive and promote tuft encapsulation but is not so high as to
damage the face yarns of the carpet. When heating with a drum
laminator, a continuous belt can be used to apply pressure to the
contacted backings and adhesives. It also is contemplated to pass
the contacted backings and adhesives between pressure or nip rolls
while the adhesive is activated to apply the desired pressure. When
using such rolls, preferred pressures range from about 7 to about
12 pounds per linear inch of carpet.
[0048] Any suitable apparatus for conducting such lamination can be
employed according to the invention. For example, backings and
composite adhesive in sheet form can be supplied from feed rolls to
and over a hot drum laminator comprising a heated drum. As noted
above, pressure rolls or a continuous belt can be used to apply
pressure to the carpet assembly. Typically, the backings contact
the drum such that the secondary backing is in contact with the
drum, thereby avoiding potential damage to face yams due to
prolonged contact between the same and the heated surface of the
drum. Conventional drying and curing ovens of the type used in
latex adhesive lamination processes also can be used, the contacted
backings and composite adhesive being passed through with a
revolving tenter frame or over rolls or other suitable means.
Cooling of the carpet structure can be accomplished by any suitable
means, for example by simply passing the carpet structure into an
ambient temperature zone or with chill rolls.
[0049] The resulting carpet structure can be subjected to
post-finishing operations as desired as is known in the carpeting
art.
[0050] It is also to be understood, unless otherwise noted herein,
that the carpet backing adhesive hot melts of the present invention
can be employed as adhesives for articles other than carpets such
as for paper articles, plastics, metals, and the like.
[0051] The present invention is illustrated in greater detail by
the specific examples presented below. It is to be understood that
these examples are illustrative embodiments and are not intended to
be limiting of the invention, but rather are to be construed
broadly within the scope and content of the appended claims.
EXAMPLE 1
[0052] An adhesive composition in accordance with the present
invention was compounded using Farrel continuous mixer having a six
(6) inch rotor and having tempered water at 65.degree. F.
circulated through the mixer body and rotor was used as a mixing
vessel. In making the adhesive blend of the present invention,
about 200 lbs/hr (90.8 kg/hr) of ethylene (meth)acrylate having 20
weight % methyl acrylate and a melt index of 20 g/10 minutes (SP
2220 X available from Eastman Chemical Company); about 1240 lbs/hr
(563 kg/hr) of calcium carbonate as a filler; about 496 lbs/hr (225
kg/hr) of a EPOLENE C10 wax; and about 60 lbs/hr (27.2 kg/hr) of
Hystrene stearic acid was added to the mixer and stirred at 350 rpm
until the components were fully molten to temperature of about
250-300.degree. F. (121-149.degree. C.) and blended. The contents
were forced through an orifice opening of about 1 inch into an
extruder. The resulting pellets were withdrawn and packaged. The
final composition of the adhesive was about 10 weight % ethylene
methylacrylate; about 25 weight % wax; about 62 weight % filler;
and about 3 weight % stearic acid.
[0053] This adhesive was then melt extruded onto a 5 tuft substrate
carpet backing with an add-on of about 0.7 lb/yd.sup.2 (0.3
kg/m.sup.2). The adhesive had good penetration on a 5 tuft carpet.
The carpet tuft bond as measured by ASTM D 1335 was greater than 11
pounds. A VELCRO.RTM. test was performed to determine the number of
fibers removed. In performing the VELCRO.RTM. test, a roller about
3 inches (7.6 cm) wide, about 2 inches (5.0 cm) in diameter and
weighing about 2 lbs (about 900 grams) has the exterior surface
area covered with a hook type material, such as VELCRO.RTM.. The
roller is moved up and down (one cycle) a piece of carpet
approximately 12 inches wide by 18 inches long (30 cm.times.46 cm).
After 10 cycles the number of fibers removed from the carpet and
adhered to the roller was observed. The carpet was then ranked from
1 (unacceptable) to 5 (acceptable) based upon the number of fibers
removed. The VELCRO.RTM. test was 5. The resultant carpet backing
was flexible, resistant to water penetration, and would not
delaminate.
EXAMPLE 2
[0054] A second adhesive composition was prepared as described
above except that 200 lbs/hr. (90.8 kg/hr) of ethylene
(meth)acrylate SP2220X; about 1240 lbs/hr (563 kg/hr) of Hymag
7030-3 as a filler (2:1 weight ratio of CaCO.sub.3: MgOH); about
496 lbs/hr (225 kg/hr) of a EPOLENE C10 wax; and about 60 lbs/hr
(27.2 kg/hr) of Hystrene stearic acid; and 4 lbs/hr. (1.5 kg/hr) of
a colorant were blended in the mixer described above. The resulting
pellets were withdrawn and packaged. The final composition of the
adhesive was about 10 weight % ethylene methylacrylate; about 24.8
weight % of a wax; about 62 weight % of a filler; and about 3
weight % of stearic acid and about 0.2 weight % of the
colorant.
[0055] This adhesive was then melt extruded onto a 5 tuft substrate
carpet backing with an add-on of about 1 lb/yd.sup.2 (0.4
kg/M.sup.2). The carpet had a tuft bond greater than 11 pounds and
had a VELCRO.RTM. test of 5, was flexible, resistant to water
penetration and would not delaminate.
COMPARATIVE EXAMPLE 1
[0056] A comparative adhesive was prepared using the procedures
described above except that 200 lb/hr of ethylene (meth)acrylate
SP2220X; about 1300 lbs/hr of calcium carbonate as a filler; and
about 500 lbs/hr of a EPOLENE C10 wax were blended together. The
resulting pellets were withdrawn and packaged. The final
composition of the adhesive was about 25 weight % wax, about 65
weight % filler, and about 10 weight % ethylene (meth)acrylate.
[0057] This adhesive was then melt extruded onto a 5 tuft substrate
carpet backing with an add-on of about 1.0 lb/yd.sup.2 (0.4
kg/m.sup.2). The adhesive penetration was poor. The VELCRO.RTM.
test was 4.5. The composition was not acceptable as a carpet
adhesive.
COMPARATIVE EXAMPLE 2
[0058] A second comparative adhesive was prepared in accordance
with the procedure of Comparative Example 1 above except the final
composition of the adhesive was 35 weight % wax, 50 weight %
filler, and 15 weight % ethylene (meth)acrylate.
[0059] This adhesive was then melt extruded onto a 5 tuft substrate
carpet backing with an add-on of about 0.75 lb/yd.sup.2 (0.3
kg/m.sup.2). The adhesive penetration was poor. The VELCRO.RTM.
test was 4.5. The composition was not acceptable as a carpet
adhesive.
COMPARATIVE EXAMPLE 3
[0060] A third comparative adhesive composition was prepared in
accordance with the procedure of Comparative Example 1 above except
the final composition of the adhesive was 42 weight % wax, 30
weight % filler and 28 weight % ethylene (meth)acrylate.
[0061] This adhesive was then melt extruded onto a 5 tuft substrate
carpet backing with an add-on of about 1.0 lb/yd.sup.2 (0.4
kg/m.sup.2). The adhesive penetration was poor and the carpet was
stiff. The VELCRO.RTM. test was 4.5. The composition was not
acceptable as a carpet adhesive.
[0062] Having described the invention in detail, those skilled in
the art will appreciate that modifications may be made to the
various aspects of the invention without departing from the scope
and spirit of the invention disclosed and described herein. It is,
therefore, not intended that the scope of the invention be limited
to the specific embodiments illustrated and described but rather it
is intended that the scope of the present invention be determined
by the appended claims and their equivalents. Moreover, all
patents, patent applications, publications, and literature
references presented herein are incorporated by reference in their
entirety for any disclosure pertinent to the practice of this
invention.
* * * * *