U.S. patent application number 14/849139 was filed with the patent office on 2016-03-10 for elastic hot melt adhesive composition and an elastic composite made with the same.
The applicant listed for this patent is H.B. FULLER COMPANY. Invention is credited to Kristy J. Beckman, Kevin P. Davis, Yuanyan Gu, Mark S. Kroll, David B. Malcolm, Peter Remmers, Thomas Wittkopf.
Application Number | 20160068721 14/849139 |
Document ID | / |
Family ID | 54147352 |
Filed Date | 2016-03-10 |
United States Patent
Application |
20160068721 |
Kind Code |
A1 |
Malcolm; David B. ; et
al. |
March 10, 2016 |
ELASTIC HOT MELT ADHESIVE COMPOSITION AND AN ELASTIC COMPOSITE MADE
WITH THE SAME
Abstract
This invention claims hot melt adhesive compositions that can be
used to form elastic composites that are useful in disposable
absorbent articles. The compositions have good elastic recovery and
high peel adhesion at a viscosity of less than about 15,000 cps at
177.degree. C. (350.degree. F.). The low viscosity makes it
possible to apply the hot melt adhesive at a high line speed and
target application to only those areas requiring elastic
performance.
Inventors: |
Malcolm; David B.;
(Maplewood, MN) ; Davis; Kevin P.; (Woodbury,
MN) ; Gu; Yuanyan; (St. Paul, MN) ; Remmers;
Peter; (Hamburg, DE) ; Wittkopf; Thomas;
(Vogelsen, DE) ; Beckman; Kristy J.; (Dellwood,
MN) ; Kroll; Mark S.; (Arden Hills, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
H.B. FULLER COMPANY |
St. Paul |
MN |
US |
|
|
Family ID: |
54147352 |
Appl. No.: |
14/849139 |
Filed: |
September 9, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62048047 |
Sep 9, 2014 |
|
|
|
62048066 |
Sep 9, 2014 |
|
|
|
62171129 |
Jun 4, 2015 |
|
|
|
Current U.S.
Class: |
442/381 ;
428/523; 524/529; 604/370 |
Current CPC
Class: |
A61L 15/58 20130101;
A61F 13/15739 20130101; B32B 27/302 20130101; B32B 7/05 20190101;
A61F 13/49009 20130101; B32B 37/1292 20130101; B32B 2437/00
20130101; A61F 2013/1591 20130101; B32B 2262/06 20130101; A61F
13/15699 20130101; B32B 5/26 20130101; C09J 2400/263 20130101; B32B
27/12 20130101; B32B 2038/0072 20130101; B32B 2307/54 20130101;
B32B 2262/0276 20130101; A61F 2013/49022 20130101; B32B 2262/04
20130101; C09J 5/06 20130101; B32B 2255/02 20130101; B32B 2307/51
20130101; B32B 2535/00 20130101; A61F 2013/49049 20130101; B32B
5/08 20130101; B32B 7/14 20130101; A61F 13/515 20130101; B32B
2037/1215 20130101; A61F 13/4902 20130101; B32B 2555/02 20130101;
B32B 2262/14 20130101; B32B 2262/0253 20130101; C09J 153/02
20130101; B32B 7/12 20130101; B32B 2305/20 20130101; C09J 153/025
20130101; A61F 13/4963 20130101; B32B 2255/26 20130101; B32B 5/022
20130101; C09J 153/00 20130101; C09J 2453/00 20130101; B32B
2307/726 20130101; A61L 15/58 20130101; C08L 25/06 20130101 |
International
Class: |
C09J 153/00 20060101
C09J153/00; B32B 27/12 20060101 B32B027/12; B32B 27/30 20060101
B32B027/30; B32B 5/02 20060101 B32B005/02 |
Claims
1. An elastic composite comprising: a first and second substrate;
and a hot melt adhesive composition between the first and second
substrates thereby permanently bonding the first and second
substrates to each other and providing elasticity in the bonded
area, said hot melt adhesive composition comprising: about 35% by
weight to about 60% by weight of one or more styrene block
copolymers wherein the one or more styrene block copolymers has an
average styrene content of at least about 30% by weight and an
average MFR (200.degree. C./5 kg) of no less than about 20, greater
than about 15% of a plasticizer and, a tackifying agent; wherein
the hot melt adhesive composition has a viscosity of less than
about 15,000 cps at 177.degree. C. (350.degree. F.).
2. The elastic composite of claim 1 wherein the hot melt adhesive
composition has a viscosity of less than about 10,000 cps at
177.degree. C. (350.degree. F.).
3. The elastic composite of claim 1 wherein the one or more styrene
block copolymers have an average styrene content of at least about
35% by weight.
4. The elastic composite of claim 1 wherein the hot melt adhesive
composition comprises from about 25% by weight to about 40% by
weight tackifying agent.
5. The elastic composite of claim 1 wherein the hot melt adhesive
composition comprises at least one tackifying agent with a melt
point of less than 100.degree. C.
6. The elastic composite of claim 1 wherein the first and second
substrate are nonwoven.
7. The elastic composite of claim 6 wherein the nonwoven is
airlaid, carded and hydroentangled.
8. The elastic composite of claim 6 wherein the nonwoven is
extensible to greater than 100% in the cross web direction.
9. The elastic composite of claim 1 wherein the hot melt adhesive
is applied to the substrate using an applicator method selected
from the group consisting of slot and non contact coating.
10. The elastic composite of claim 1 wherein the hot melt adhesive
is applied to the substrate using an applicator method selected
from the group consisting of screen printing, spraying, comb shim
slot and gravure roll.
11. A disposable article comprising the elastic composite of claim
1.
12. The disposable article of claim 11 wherein the elastic
composite is used in an application selected from the group
consisting of ear, waist band, belly band and side panel.
13. The disposable article of claim 11 selected from the group
consisting of diaper, adult incontenence product, feminine hygiene
product and medical bandage.
14. A hot melt adhesive composition that can be used to create a
bonded, elasticized region, comprising: from about 35% to about 60%
by weight of one or more styrene block copolymers wherein the one
or more styrene block copolymers has an average styrene content of
at least about 35% and an average MFR (200.degree. C./5 kg) of no
less than about 20, greater than about 15% plasticizing oil and, a
tackifying agent wherein the adhesive composition has a viscosity
of less than about 15,000 cps at 177.degree. C. (350.degree.
F.).
15. The hot melt adhesive of claim 14 wherein the hot melt adhesive
composition has a Viscosity Ratio (Viscosity @ 149.degree. C.
(300.degree. F.) (cps)/Viscosity @ 177.degree. C. (350.degree. F.)
of no greater than about 5.
16. The hot melt adhesive composition of claim 14 wherein the
tackifying agent is a hydrocarbon resin with about 5% to about 20%
by weight of aromatic content and the plasticizing oil is a
naphthenic oil.
17. A hot melt adhesive composition that can be used to create a
bonded, elasticized region, comprising: from about 40% to about 50%
by weight of one or more styrene block copolymers wherein the one
or more styrene block copolymers has an average styrene content of
at least about 35% and an average MFR (200.degree. C./5 kg) of no
less than about 20, from about 15% to about 30% of a naphthenic
plasticizing oil and, from about 30% to about 40% by weight of an
aromatic modified hydrocarbon resin; wherein the adhesive
composition has a viscosity of less than about 15,000 cps at
350.degree. F.
18. The hot melt adhesive of claim 17 wherein at least one of the
styrene block copolymers has a diblock content of greater than
about 30% by weight.
19. The hot melt adhesive of claim 17 wherein the average styrene
content of the one or more styrene block copolymers is at least
about 40% by weight.
20. An elastic composite comprising: a nonwoven substrate, and the
hot melt adhesive composition of claim 14 bonded to the substrate;
wherein the hot melt adhesive provides elasticity to the bonded
area.
Description
[0001] This application claims priority to and benefit of
provisional filed patent application Nos. 62/048047 and 62/048066
filed on Sep. 9, 2014 and provisional patent application No.
62/171129 filed on Jun. 4, 2015.
BACKGROUND
[0002] Adhesives are often used to bond substrates together. In the
area of industrial adhesives, hot melt adhesives are commonly used
to bond together a wide variety of articles including disposable
absorbent articles comprising non-woven substrates e.g. diapers,
training paints, surgical garments, swim wear, absorbent
underpants, adult incontinence products, sanitary napkins and
medical dressings (e.g. wound care products).
[0003] There can be multiple hot melt adhesives used in the
manufacture of a disposable absorbent article. For example, in the
manufacture of a disposable diaper, hot melt adhesives are used for
construction (e.g. bonding the backsheet to the nonwoven and
optionally the absorbent pad), elastic attachment (e.g. bonding the
elastic material to the backsheet in for example the leg or waist
area), and for the core stabilization (e.g. applying a hot melt
adhesive to the absorbent core to increase the strength of the
core).
[0004] Hot melt adhesives can also be used to form elastic
composites that are useful in disposable articles. Currently,
elastic composites are often formed in a 5-layer configuration
including the following layers: nonwoven, hot melt adhesive,
elastic material, hot melt adhesive, nonwoven. The hot melt
adhesive bonds the non-adhesive elastic to the nonwoven to form a
composite.
[0005] Alternately, a hot melt adhesive with elastic properties can
replace both the elastic material and the adhesive layers to form a
simplified 3-layer elastic composite that can impart stretch to
various portions of the disposable article.
SUMMARY
[0006] In one embodiment, the invention includes an elastic
composite including a first and second substrate; and a hot melt
adhesive composition between the first and second substrates
thereby permanently bonding the first and second substrates to each
other and providing elasticity in the bonded area, said hot melt
adhesive composition including about 35% by weight to about 60% by
weight of one or more styrene block copolymers, wherein the one or
more styrene block copolymers has an average styrene content of at
least about 30% by weight and an average MFR (200.degree. C./5 kg)
of no less than about 20, greater than about 15% of a plasticizer
and, a tackifying agent; wherein the hot melt adhesive composition
has a viscosity of less than about 15,000 cps at 350.degree. F.
[0007] In one aspect, the elastic composite includes a hot melt
adhesive composition with a viscosity of less than about 10,000 cps
at 350.degree. F. In another aspect, the one or more styrene block
copolymers have an average styrene content of at least about 35% by
weight. In a different aspect, the elastic composite includes a hot
melt adhesive composition includes from about 25% by weight to
about 40% by weight tackifying agent.
[0008] In another aspect, the elastic composite includes a hot melt
adhesive composition comprises at least one tackifying agent with a
melt point of less than 100.degree. C.
[0009] In one aspect, elastic composite includes a first and second
substrate that are nonwoven. In a different aspect, the nonwoven is
airlaid, carded and hydroentangled. In another aspect, the nonwoven
is extensible to greater than 100% in the cross web direction.
[0010] In one aspect, the hot melt adhesive of the elastic
composite is applied to the substrate using an applicator method
selected from the group consisting of slot and non contact coating.
In a different aspect, the hot melt adhesive is applied to the
substrate using an applicator method selected from the group
consisting of screen printing, spraying, comb shim slot and gravure
roll.
[0011] In another embodiment, includes a disposable article that
includes the elastic composite. In one aspect, the elastic
composite is used in an application selected from the group
consisting of ear, waist band, belly band and side panel. In
another aspect, the disposable article is selected from the group
consisting of diaper, adult incontenence product, feminine hygiene
product and medical bandage.
[0012] In one aspect, the invention includes a hot melt adhesive
composition that can be used to create a bonded, elasticized
region, including from about 35% to about 60% by weight of one or
more styrene block copolymers wherein the one or more styrene block
copolymers has an average styrene content of at least about 35% and
an average MFR (200.degree. C./5 kg) of no less than about 20,
greater than about 15% plasticizing oil and, a tackifying agent
where the adhesive composition has a viscosity of less than about
15,000 cps at 350.degree. F.
[0013] In one embodiment, the hot melt adhesive composition has a
Viscosity Ratio (Viscosity @ 300.degree. F. (cps)/Viscosity @ 3
350.degree. F.) of no greater than about 5. In another embodiment,
the tackifying agent is a hydrocarbon resin with about 5% to about
20% by weight of aromatic content and the plasticizing oil is a
naphthertic oil.
[0014] In another aspect, the invention includes a hot melt
adhesive composition that can be used to create a bonded,
elasticized region, including from about 40% to about 55% by weight
of one or more styrene block copolymers wherein the one or more
styrene block copolymers has an average styrene content of at least
about 35% and an average MER (200.degree. C./5 kg) of no less than
about 20, from about 15% to about 30% of a naphthenic plasticizing
oil and, from about 30% to about 40% by weight of an aromatic
modified hydrocarbon resin where the adhesive composition has a
viscosity of less than about 15,000 cps at 350.degree. F.
[0015] In one embodiment, at least one of the styrene block
copolymers has a diblock content of greater than about 30% by
weight. In another embodiment, the average styrene content of the
one or more styrene block copolymers is at least about 40% by
weight. In still another embodiment, the one or more styrene block
copolymers has an average MFR (200.degree. C./5 kg) of no less than
about 30.
[0016] In another aspect, the elastic composite includes a
substrate, and a hot melt adhesive composition that can be used to
create a bonded, elasticized region, including from about 35% to
about 60% by weight of one or more styrene block copolymers wherein
the one or more styrene block copolymers has an average styrene
content of at least about 35% and an average MFR (200.degree. C./5
kg) of no less than about 20, greater than about 15% plasticizing
oil and, a tackifying agent where the adhesive composition has a
viscosity of less than about 15,000 cps at 350.degree. F. and
wherein the hot melt adhesive provides elasticity to the bonded
area.
DETAILED DESCRIPTION
[0017] Applicants have discovered hot melt adhesive compositions
that can be used to form elastic composites that are useful in
disposable articles (e.g. disposable absorbent articles). The
compositions have good elastic recovery and high peel adhesion and
have a viscosity of less than about 15,000 cps at 350.degree. F.
The low viscosity makes it possible to apply the hot melt adhesive
at a high line speed and register i.e. provide zoned application to
only those areas requiring elastic performance. The low viscosity
further makes it possible to apply the hot melt adhesive within the
disposable article manufacturing line.
Elastic Composite
[0018] The elastic composite can include a first substrate and a
hot melt adhesive composition. The hot melt adhesive composition
imparts elasticity to the first substrate.
[0019] Alternately, the elastic composite can include a first
substrate, a second substrate and a hot melt adhesive composition.
The hot melt adhesive composition is present between the first and
second substrate, permanently bonding the substrates to each other
and providing elasticity in the bonded area.
[0020] At least one of the substrates is selected from the group
consisting of nonwoven and polymer film.
[0021] Any nonwoven can be used. The nonwoven can be an elastic
nonwoven (e.g. core and shell type). The nonwoven can contain
fibers made from one or more polymers (e.g. PET (polyethylene
terephthalate), PBT (polybutylene terphthalate), nylon,
polypropylene and polyethylene), one or more natural fibers (e.g.
rayon cellulose, cotton cellulose, hemp and viscose) or
combinations thereof. The nonwoven can be formed by a number of
different methods, including e.g. airlaid, wetlaid, spunbound or
meltblown. The fibers can be carded (e.g. run through a comb) so
that they are oriented in a particular direction. The webs can be
bonded together in any manner including e.g. hydroentangled,
chemical bonded, needle punched or thermally bonded. In one
embodiment, the nonwoven is comprised of a blend of polypropylene
and polyethylene fibers which are airlaid, carded and
hydroentangled.
[0022] Any polymer film can be used. The polymer film can be
selected from the group consisting of polyethylene, polypropylene,
polyethylene copolymers, polypropylene copolymers, and PET.
[0023] The first and second substrates can be nonwoven. The
nonwoven can have a basis weight of less than 40 grams per square
meter (gsm), less than 35 gsm, or even less than about 30 gsm. The
nonwoven can be extensible to greater than 100% in the cross-web
direction.
[0024] Various post treatments, such as treatment with grooved
rolls i.e. activation can be used to adjust the mechanical
properties (e.g. extensibility) of the composite.
[0025] The hot melt adhesive can be applied to the first and or
second substrate using a variety of applicator methods including
slot coating, non-contact coating, comb shim coating, spraying
including, e.g., spiral spraying and random spraying, screen
printing, foaming (e.g. using chemical foaming agents or Nordson
FoamMelt.RTM. Dispensing equipment), engraved roller, gravure
roller, extrusion and meltblown.
[0026] The hot melt adhesive can be applied to one substrate.
[0027] Alternatively, the hot melt adhesive can be applied to the
first substrate and then contacted by the second substrate to form
the composite. Pressure,tension and/or line speed can be used to
aid in forming the bonded composite. The composite can be formed
within a disposable article manufacturing process. Alternatively,
the composite is formed prior to the disposable article
manufacturing process.
[0028] In one embodiment, the elastic composite is formed by
applying the hot melt adhesive using a discontinuous application
method. The hot melt adhesive application method can be selected
from the group consisting of comb shim coating and spraying.
Alternatively, any other method of coating could be used to give a
discontinuous coating. In one embodiment, the bonded elastic region
alternates with an area free of adhesive in a vertical stripe
pattern throught the absorbent article. These vertical stripes can
be more like a pin stripe. In one embodiment, the bonded elastic
region is a 2 to about 10 mm wide stripe and the area free of
adhesive is a 0.5 to about 5 mm wide stripe, or even a 0.5 to about
3 mm wide strip. Having areas free of adhesive, or using a
discontinuous method of hot melt adhesive application to form the
elastic composite can be useful to give breathability to the
composite.
Hot Melt Adhesive Composition
[0029] The hot melt adhesive can be a pressure sensitive adhesive
(i.e. have some tack at room temperature). The hot melt adhesive
composition can be light in color and can have good thermal
stability. In a cooled film, the hot melt adhesive can be clear
i.e. translucent or alternatively the hot melt adhesive can be
opaque. The hot melt adhesive can have an initial Molten Gardner
Color after manufacturing of less than about 3, or even less than
about 2. Alternately, the hot melt adhesive can be pigmented to an
opaque color such as e.g. pink, blue, white, gray, etc.
[0030] The hot melt adhesive composition has low viscosity at
application temperature. The viscosity can be no greater than about
15,000 cps at around 177.degree. C. (350.degree. F.), no greater
than about 10,000 cps at around 177.degree. C. (350.degree. F.), no
greater than about 7,500 cps at around 177.degree. C. (350.degree.
F.), or even no greater than about 5,000 cps at 177.degree. C.
(350.degree. F.). The hot melt adhesive composition gives a set
after 50% hysterisis of no more than about 20%, no more than about
12%, no more than about 10% or even no more than about 8% when
tested according to the 2-Peak Hysterisis Test Method.
[0031] The hot melt adhesive composition provides good adhesion
when tested according to the Peel Force Test Method. In some
embodiments, the hot melt adhesive has peel adhesion of greater
than about 100 grams/inch, greater than about 200 grams/inch, or
even greater than about 300 grams/inch.
[0032] The hot melt adhesive composition includes one or more
styrene block copolymers, a tackfying agent, and greater than about
15% by weight of a plasticizer.
[0033] The hot melt adhesive composition can have a viscosity curve
with a Viscosity Ratio (Viscosity @ 149.degree. C. (300.degree. F.)
(cps)/Viscosity @ 177.degree. C. (350.degree. F.)) that is no
greater than about 7.5, no greater than about 6, no greater than
about 5, or even no greater than about 4. A low viscosity ratio can
indicate improved machining at high line speeds as the hot melt
adhesive gains viscosity more slowly as it cools.
[0034] The hot melt adhesive composition can include a tackifying
agent with at least some aromatic content and a naphthenic oil.
[0035] Styrene Block Copolymers
[0036] The hot melt adhesive includes one or more styrene block
copolymers.
[0037] A styrene block copolymer includes an aromatic vinyl polymer
block and a conjugated diene polymer block, a. hydrogenated
conjugated diene polymer block, or a combination thereof. The
blocks can be arranged in a variety of configurations including,
e.g., linear, branched, radial, star block, and combinations
thereof. The aromatic vinyl polymer block can be derived from a
variety of aromatic vinyl compounds including, e.g., styrene,
alpha-methylstyrene, beta-methylstyrene, o-, m-, p-methylstyrene,
t-butylstyrene, 2,4,6-trimethylstyrene, monofluorostyrene,
difluorostyrene, monochlorostyrene, dichlorostyrene,
methoxystyrene, 1,3-vinylnaphthalene, vinylanthracene, indene,
acenaphthylene, and combinations thereof. The diene polymer block
can be derived from a variety of diene-containing compounds
including, e.g., isoprene, butadiene, hexadiene,
2,3-dimethyl-1,3-butadiene, 3-pentadiene, and hydrogenated versions
thereof and combinations thereof.
[0038] Useful styrene block copolymers include, e.g., diblock,
triblock and multiblock copolymers including, e.g.,
styrene-butadiene, styrene-butadiene-styrene, styrene-isoprene,
styrene-isoprene-styrene, styrene-ethylene/butene,
styrene-ethylene/butene-styrene, styrene-ethylene/propylene,
styrene-ethylene/propylene-styrene,
styrene-ethylene-ethylene/propylene-styrene, farnesene styrene and
combinations thereof and hydrogenated or functionatized versions
thereof.
[0039] The one or more styrene block copolymers have an average
styrene content of at least about 30%, at least about 35%, at least
about 40%, or even from about 35% to about 45% by weight.
[0040] As an example, if a hot melt composition comprises two
styrene block copolymers A and B. Polymer A is present at 25 weight
% with a styrene content of 35% and polymer B is present at 25
weight % with a styrene content of 45 weight %. The average styrene
content of the one or more styrene block copolymers is calculated
in the following way: 0.5 (35)+0.5 (45)=40 weight %.
[0041] The one or more styrene block copolymers have an average
Melt Flow Rate (MFR) according to ASTM D 1238 (200.degree. C./5 kg)
in dg/min of no less than about 20 dg/min, no less than about 25
dg/min, or even no less than about 30 dg/min. The average MFR of
the styrene block copolymers is calculated in a similar manner as
the average styrene content.
[0042] The hot melt adhesive can include at least one styrene block
copolymer with a styrene content of at least about 40% by
weight.
[0043] The composition has a total styrene block copolymer content
of greater than 40% by weight, greater than 45% by weight, from
about 35% to about 60% by weight, or even from about 40% to about
50% by weight.
[0044] The styrene block copolymers can be pure tri-block
copolymers containing no di-block. Alternately, the styrene block
copolymer can include a portion of di-block. The styrene block
copolymer can include diblock content of greater than 30%.
[0045] Useful styrene block copolymers include VECTOR 6241 (Linear,
styrene-butadiene-styrene, pure triblock copolymer, 43 wt %
styrene, MFR (200.degree. C./5 kg)=23 dg/min), VECTOR 8508 (Linear,
styrene-butadiene-styrene, pure triblock copolymer, 29 wt %
styrene, MFR (200.degree. C./5 kg)=12 dg/min and VECTOR 4411
(Linear, styrene-isoprene-styrene, pure triblock copolymer, 44 wt %
styrene, MFR (200.degree. C./5 kg)=40 dg/min) all available from
TSRC Dexco (Houston, Tex.) and GLOBALPRENE 3545 (Linear,
styrene-butadiene-styrene block copolyer, 63% diblock, 45 wt %
styrene, MFR (190.degree. C./5 kg)=55) available from LCY CHEMICAL
CORP. (Taipei, Taiwan).
[0046] Tackifying Agent
[0047] The hot melt adhesive includes a tackifying agent. The
tackifying agent can be fluid or solid at room temperature.
Suitable classes of tackifying agents include, e.g., aromatic,
aliphatic and cycloaliphatic hydrocarbon resins, mixed aromatic and
aliphatic modified hydrocarbon resins, aromatic modified aliphatic
hydrocarbon resins, and hydrogenated versions thereof; terpenes,
modified terpenes and hydrogenated versions thereof; natural
rosins, modified rosins, rosin esters, and hydrogenated versions
thereof; low molecular weight polylactic acid; and combinations
thereof. Examples of useful natural and modified rosins include gum
rosin, wood rosin, tall oil rosin, distilled rosin, hydrogenated
rosin, dimerized rosin and polymerized rosin. Examples of useful
rosin esters include e.g., glycerol esters of pale wood rosin,
glycerol esters of hydrogenated rosin, glycerol esters of
polymerized rosin, pentaerythritol esters of natural and modified
rosins including pentaerythritol esters of pale wood rosin,
pentaerythritol esters of hydrogenated rosin, pentaerythritol
esters of tall oil rosin, and phenolic-modified pentaerythritol
esters of rosin.
[0048] Useful tackifying agents are commercially available under a
variety of trade designations including, e.g., the ESCOREZ series
of trade designations from Exxon Mobil Chemical Company (Houston,
Tex.) including ESCOREZ 5400 (1% aromatic content), ESCOREZ 5600
(9.8% aromatic content), ESCOREZ 5690 (10% aromatic content),
ESCOREZ 5615 (9.9% aromatic content), the EASTOTAC series of trade
designations from Eastman Chemical (Kingsport, Tenn.) including
EASTOTAC H-100R and EASTOTAC H-100L, and the WINGTACK series of
trade designations from Cray Valley HSC (Exton, Pa.) including
WINGTACK 86, WINGTACK EXTRA, and WINGTACK 95 and the PICCOTAC and
KRISTALEX series of trade designations from Eastman Chemical
Company (Kingsport, Tenn.) including, e.g., PICCOTAC 8095 and
KRISTALEX 3100.
[0049] The hot melt adhesive can be free from end block resin that
has a melting point greater than about 110.degree. C., greater than
about 120.degree. C., or even greater than about 130.degree. C.
[0050] The hot melt adhesive composition can include at least one
tackifying agent with aromatic content. The tackifying agent can
have an aromatic content of greater than 5%, greater than 20%,
greater than 50%, from about 5% to about 20% by weight, or even
from about 7.5% to about 15% by weight. The aromatic content is
measured by Nuclear Magnetic Resonance (NMR) spectroscopy.
[0051] The composition can include a tackifying agent with a melt
point of less than 100.degree. C., or even less than 95.degree.
C.
[0052] The hot melt adhesive composition can include at least about
20% by weight, at least about 25% by weight, from about 10% by
weight to about 50% by weight, from about 15% by weight to about
40% by weight, or even from about 20% by weight to about 37% by
weight tackifying agent.
[0053] Plasticizer
[0054] The hot melt adhesive composition includes a plasticizer.
Suitable plasticizers include, e.g., napinhenic oils, paraffinic
oils (e.g., cycloparaffin oils), mineral oils, phthalate esters,
adipate esters, olefin oligomers (e.g., oligomers of polypropylene,
polybutene, and hydrogenated polyisoprene), polybutenes,
polyisoprene, hydrogenated polyisoprene, polybutadiene, benzoate
esters, animal oil, plant oils (e.g. castor oil, soybean oil (e.g.
high oleic soy oil), derivatives of oils, glycerol esters of fatty
acids, polyesters, polyethers, lactic acid derivatives and
combinations thereof.
[0055] Useful commercially available plasticizers include CALSOL
550 naphthenic oil from Calumet Specialty Products Partners, LP
(Indianapolis, Ind.), KAYDOL OIL mineral oil from Sonneborn
(Tarrytown N.Y.) PARAPOL polybutene from Exxon Mobil Chemical
Company (Houston, Tex.), OPPANOL polyisobutylene from BASF
(Ludwigsjhafen, Germany), KRYSTOL 550 mineral oil from Petrochem
Carless Limited (Surrey, England), PURETOL 35 and 15 both mineral
oils from Petro Canada Lubricants Inc. (Mississauga, Ontario) and
PLENISH from Pioneer Dupont.
[0056] The plasticizer can be a naphthenic oil. Alternately, the
plasticizer includes aromatic or naphthenic groups.
[0057] The plasticizer is present in the hot melt adhesive
composition in an amount of at least about 15% by weight, at least
about 18% by weight, from about 10% to about 30% by weight, or even
from about 15% to about 25% by weight.
[0058] Wax
[0059] The hot melt adhesive composition can include a wax. Useful
classes of wax include, e.g., paraffin waxes, microcrystalline
waxes, high density low molecular weight polyethylene waxes,
by-product polyethylene waxes, polypropylene waxes, Fischer-Tropsch
waxes, oxidized Fischer-Tropsch waxes, functionalized waxes such as
acid, anhydride, and hydroxy modified waxes, animal waxes,
vegetable waxes (e.g. soy wax) and combinations thereof. Useful
waxes are solid at room temperature and preferably have a Ring and
Ball softening point of from 50.degree. C. to 170.degree. C. Useful
waxes are commercially available from a variety of suppliers
including EPOLENE N and C series of trade designations from
Westlake Chemical Corporation (Houston, Tex.) including e.g.
EPOLENE N-21 and the LICOCENE series of trade designations from
Clariant International Ltd. (Muttenz, Switzerland) including e.g.
TP LICOCENE PP 6102.
[0060] The hot melt adhesive composition can include no greater
than about 8.0% by weight, no greater than about 5% by weight, from
about 1% by weight to about 7.5 by weight, or even from about 1% to
about 5% by weight wax.
[0061] Additional Components
[0062] The hot melt adhesive composition optionally includes
additional components including but not limited to, e.g., foaming
agents, stabilizers, antioxidants, additional polymers (e.g. olefin
based polymers (e.g. propylene homopolymers, propylene copolymers,
ethylene homopolymers, ethylene copolymers, etc.), functionalized
polymers such as acid, anhydride, and hydroxy modified polymers),
amorphous poly-alpha olefins), adhesion promoters, ultraviolet
light stabilizers, corrosion inhibitors, odor
absorbers/neutralizers, colorants (e.g., pigments (e.g. titanium
dioxide, carbon black, and mixtures thereof) and dyes), fragrances,
fillers (e.g. nano particles, calcium carbonate, clay, talc, fumed
silica), surfactants, wetness indicators, superabsorbents,
coextrusion coatings, processing aids and combinations thereof.
[0063] The hot melt adhesive can comprise from about 0.05 to about
2.0% by weight pigment, or even from about 0.05 to about 0.5%
pigment.
[0064] Useful antioxidants include, e.g., pentaerythritol
tetrakis[3,(3,5-di-tert-butyl-4-hydroxyphenyl)propionate],
2,2'-methylene bis(4-methyl-6-tert-butylphenol), phosphites
including, e.g., tris-(p-nonylphenyl)-phosphite (TNPP) and
bis(2,4-di-tert-butylphenyl)4,4'-diphenylene-diphosphonite,
di-stearyl-3,3'-thiodipropionate (DSTDP), and combinations thereof.
Useful antioxidants are commercially available under a variety of
trade designations including, e.g., the IRGANOX series of trade
designations including, e.g., IRGANOX 1010, IRGANOX 565, and
IRGANOX 1076 hindered phenolic antioxidants and IRGAFOS 168
phosphite antioxidant, all of which are available from BASF
Corporation (Florham Park, N.J.), and ETHYL 702 4,4'-methylene
bis(2,6-di-tert-butylphenol). When present, the hot melt adhesive
composition preferably includes from about 0.1% by weight to about
2% weight antioxidant.
Disposable Article
[0065] The hot melt adhesive compositions and elastic composites of
this invention can be incorporated into any suitable article
including personal care garments, medical garments and industrial
worker garments.
[0066] The elastic composite of this invention is useful in a
variety of applications and constructions to improve comfort and
fit including e.g., disposable absorbent articles including, e.g.,
diapers, training pants, swim wear, absorbent underpants, adult
incontinence products, sanitary napkins, medical dressings (e.g.,
wound care products and bandages), surgical pads, medical gowns,
caps, gloves, drapes, face masks, laboratory coats, coveralls,
meat-packing products, and components of absorbent articles
including, e.g., an absorbent clement, absorbent cores, impermeable
layers (e.g., backsheets), tissue (e.g., wrapping tissue),
acquisition layers and woven and nonwoven web layers (e.g., top
sheets, absorbent tissue).
[0067] The elastic composite of this invention is useful for
elasticizing many areas of disposable articles including leg cuffs,
waist portions, belly bands, side panels and fastening tabs/ears.
The elastic composite of this invention can further be use to
elasticize any portion. of the disposable article, one or more
portions of the disposable article, or even the entire disposable
article.
EXAMPLES
[0068] Composition amounts in tables are all in weight %.
Test Procedures
[0069] Test procedures used in the examples and throughout the
specification, unless stated otherwise, include the following.
Viscosity Test Method
[0070] Viscosity is determined in accordance with ASTM D-3236
entitled, "Standard Test Method for Apparent viscosity of Adhesives
and Coating Materials," (Oct. 31, 1988), using a Brookfield
Thermoset viscometer Model RVDV 2 and a number 27 spindle. The
results are reported in centipoise (cps).
Molten Gardner Color
[0071] The hot melt adhesive is tested (in the molten state) to
determine Molten Gardner Color by comparing the color of the sample
against the Gardner Color Standards as set forth in ASTM D-1544.
The comparison is made using a Gardner Delta Comparator equipped
with an Illuminator available from Pacific Scientific (Bethesda,
Md.).
Test Lamination Preparation
[0072] Test laminations were prepared by continuous slot coating
the elastic hot melt adhesive composition between two nonwoven*
substrates at an application temperature of 177.degree. C.
(350.degree. F.), a nip pressure of 10.5 Newtons/centimeter (N/cms)
(6 pounds per linear inch (PLI)), and a run speed of at least 6.1
meters/min (m/min) (20 feet/min). Laminations were prepared with an
adhesive coat weight of 100 grams per square meter (gsm) and the
width of the adhesive was at least 7.6 cms (3 inches). A sufficient
amount of laminate was prepared such that at least 1.5 m (60
inches) of representative lamination was collected for testing.
*The nonwoven used is carded, hydroentangled and comprises 50/50
(PET/PP). It has a basis weight of 29 g/m.sup.2, a cross direction
tensile strength of 93 grams/cm.sup.2 (600 grams/in.sup.2), a CD
elongation at break=217% WSP Method 110.4, and an elongation ratio
(CD/MD)=4.3.
Peel Force Test Method
[0073] Test laminates were prepared by coating adhesive between two
substrates according to the Test Lamination Preparation method
above. Peel force is determined using ASTM D1876-01 entitled; "Test
Method for Determining Peel Resistance of Adhesive (T-Peel Test
Method)," with the exception that the test is run at a rate of 30.5
cms per minute (12 inches per minute), instead of 25.4 cms per
minute (10 in per minute), over a period of 10 seconds, and 7
replicates are run instead of the 10 specified in ASTM D1876. The
samples are run on on INSTRON type-test instrument. The test
samples are 2.54 cms (1 inch) in width and at least 10.16 cms (4
inches) in length. The average peel force over 10 seconds of
peeling is recorded, and the results are reported in grams. The
initial peel force is measured at least 24 hours after the laminate
is prepared.
2-Peak Hysteresis Test Method
[0074] Test laminates were prepared by coating hot melt adhesive
between two substrates according to the Test Lamination Preparation
method above. Test samples are prepared by cutting the laminates in
cross-web direction, with 1 inch in width and at least 3 inches in
length. The test is conducted at least 24 hours after the non-woven
laminate is prepared.
[0075] The strips prepared are extended to a certain strain (e.g.
50%, 100%, 150% or 200%) and then retracted to their original
dimension. Subsequently the specimen goes through a second
extension-retraction cycle with the same deformation. The cross
head speed is set to 50.8 cms per minute (20 inches per minute).
There is no holding time between extension and retraction. The
samples are run on an INSTRON type-test instrument with at least 3
replicates. The permanent set after each cycle is determined by the
tensile strain on the retraction curve when the tensile stress
reduces to 5 gram force. The peak loadlstress at maximum
deformation, and percent energy loss between each cycles are also
recorded.
Rheological Creep and Recovery
[0076] Rheological Creep and Recovery was run on a Texas
Instruments AR-G2 rheometer using parallel plate geometry with a 8
mm plate. The test was run isothermally at 38.degree. C. with a gap
of 300 um.
[0077] Once equilibrated at 38.degree. C., a pressure of 26,800 Pa
was applied. The sample was held at this pressure for 20 minutes
(creep portion of test). The pressure was then released to 0 Pa for
20 minutes (recovery portion of test).
[0078] The strain was measured. Values at specified intervals are
reported in the table.
TABLE-US-00001 TABLE ONE Comparative 1 and 2 are compositions
outside of the inventive ranges (Comparative 1 has less than 15%
plasticizer and Comparative 2 has a styrene block copolymer with an
average MFR of 12 dg/Min. Both have a viscosity at 350.degree. F.
of greater than 15,000 cps). Both would be expected not to apply
well on a high speed production line. Comparative 1 Comparative 2
VECTOR 8508 40 45 (Avg. MFR (200.degree. C./5 kg) = 12) ESCOREZ
5615 49.5 29.5 CALSOL 550 10 25 IRGANOX 1010 0.5 0.5 Viscosity @
350.degree. F. (cps) 43,400 30,870
TABLE-US-00002 TABLE TWO Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 VECTOR
6241 20 VECTOR 4411 46 46 46 42.5 42.5 26 ESCOREZ 5490 32 ESCOREZ
5400 33.5 ESCOREZ 5690 33.5 33.5 32 31.5 PURETOL 35 20 20 25 CALSOL
550 20 25 22 PLENISH IRG 1010 0.5 0.5 0.5 0.5 0.5 0.5 Viscosity
(cps) @149.degree. C. 204,500 68,000 38,800 77,000 18,250 33,500
(300.degree. F.) @177.degree. C. 14,050 9,700 8,020 6,950 4,210
8,940 (350.degree. F.) Viscosity 14.56 7.01 4.83 11.10 4.34 3.75
Ratio @149.degree. C./ @177.degree. C. Rheo. Creep Strain @ .078
.067 0.01 sec Strain @ .232 .169 600 sec Strain @ .246 .192 1200
sec Rheo. Recovery Strain @ .246 .192 1200 sec Strain @ .05 .041
1800 seconds Strain @ .043 .033 2400 sec Ex. 7 Ex. 8 Ex. 9 Ex. 10
Ex. 11 VECTOR 6241 20 VECTOR 4411 26 50 50 35 35 ESCOREZ 5490 29.5
29.5 38.5 ESCOREZ 5400 ESCOREZ 5690 31.5 29.5 38.5 PURETOL 35 20 26
CALSOL 550 20 26 PLENISH 22 IRG 1010 0.5 0.5 0.5 0.5 0.5 Viscosity
(cps) @149.degree. C. 28,100 279,600 74,800 18400 6000 (300.degree.
F.) @177.degree. C. 7,750 30,150 12,550 2545 2065 (350.degree. F.)
Viscosity 3.63 9.27 6.0 7.23 2.91 Ratio @149.degree. C./
@177.degree. C. Rheo. Creep Strain @ .052 .084 .078 0.01 sec Strain
@ .162 .457 .377 600 sec Strain @ .189 .488 .424 1200 sec Rheo.
Recovery Strain @ .189 .488 .424 1200 sec Strain @ .048 .106 .104
1800 seconds Strain @ .039 .094 .087 2400 sec
TABLE-US-00003 TABLE THREE Ex. 12 Ex. 13 Ex. 6 Ex. 14 Ex. 15 Ex. 16
Ex. 17 VECTOR 8508 20 15 VECTOR 4411 26 31 26 26 46.5 VECTOR 6241
20 20 30 46.5 GLOBALPRENE 3545 15 Avg. Styrene 37.5 39.1 43.6 43.6
43.7 44 43 Content of SBC Avg. MFR 27.8 30.9 32.6 32.6 >33 40 23
(200.degree. C./5 kg) ESCOREZ 5690 31.5 31.5 31.5 33.5 29.75 29.75
ESCOREZ 5615 34.5 CALSOL 550 22 22 22 20 20 23.25 23.25 IRGANOX
1010 0.5 0.5 0.5 0.5 0.5 0.5 0.5
TABLE-US-00004 TABLE FOUR Ex. 12 Ex. 13 Ex. 6 Ex. 14 Ex. 15 Ex. 16
Ex. 17 Viscosity (cps) @149.degree. C.(300.degree. F.) 47,000
48,590 33,500 33,000 33,800 35,150 37,800 @163.degree.
C.(325.degree. F.) 23,125 21,570 16,290 16,150 17,750 14,250 18,850
@177.degree. C.(350.degree. F.) 12,700 12,800 8,940 9,250 11,050
7,050 12,050 Viscosity Ratio 3.70 3.80 3.75 3.56 3.06 4.99 3.11
@149.degree. C./177.degree. C. 2-Peak Hysteresis Testing 50%
hysteresis Set 1.sup.st cycle (%) 6 6 6 8 9 6 5 Set 2.sup.nd cycle
(%) 7 6 7 10 10 7 6 Energy loss (%) 31.1 31.1 35.1 37.0 37.9 35.1
34.5 100% hysteresis Set 1.sup.st cycle (%) 15 14 15 21 23 16 14
Set 2.sup.nd cycle (%) 17 17 17 23 26 18 16 Energy loss (%) 43.0
44.2 46.7 48.7 51.2 46.9 45.6 150% hysteresis Set 1.sup.st cycle
(%) 24 24 27 37 41 26 23 Set 2.sup.nd cycle (%) 27 27 30 40 45 28
27 Energy loss (%) 54.3 55.1 55.2 59.8 61.6 56.2 54.4 Adhesion
Average peel 278 238 437 256 852 68 272 (gram force)
* * * * *