Note: Descriptions are shown in the official language in which they were submitted.
1083291
ADI~ ES I VE B LENDS
Background of the Invention
various polymer and resin mixtures have been proposed
for adhesives witll strong bonding properties for various
substrates and these have been successful to varying degrees.
~lowever, the blends of this invention have remarkably superior
properties when used as adhesives. Thus the object of this
invention is to provide modified polyolefin resins with improved
adhesion to substrates such as polar polymers, metals, glass,
paper, wood, etc. These resins can be applied in any
conventional manner and typical application processes are
lamination, extrusion coating, coextrusion, powder coating, blow
molding, etc.
It is well known that laminates of polyolefins with
dissimilar substrates have many desirable characteristics.
Among these are heat sealability and barrier properties.
However, it is often difficult to bond polyolefins to dissimilar
substrates because of the differences in physical and chemical
structures. To overcome the bonding difficulties, it has been
proposed in the past to use either an adhesive layer between the
polyolefin and the substrate or a more expensive, highly polar
copolymer of the olefin such as an ionomer resin in place of the
- conventional polyolefin. This latter is not entirely successful
- because, although the ionomer resin may show good adhcsion, the
bond formed is easily weakened by exposure to moisture or common
solvents.
Another method for improving the adhesion of a
polyolefin to a substrate is to graft polar functional groups
onto the polyolefin backbone chain. The most common combination
is maleic anhydride grafted to polypropylene. However, grafting
- of maleic anhydride on a polyethylene backbone when applicd as
in this invention does not give the adhesive power of the
products of this invention.
'; . -1- $~
;
.~ . .
1~83Z91
Summary of the Invention
.
By grafting suitable unsaturated fused ring carboxylic
acid anhydrides to a high density polyethylene and blending the
resultant graft copolymer with a polyethylene resin that is
either a homopolymer of ethylene, a copolymer of ethylene and an
alpha-olefin, or a terpolymer of ethylene, an alpha-olefin and a
diene or a mixture of these, we have obtained composites with
excellent adhesive strength to various substrates including
polar polymers, metals, glass, paper, wood and the like. These
composites also have exceptional heat sealability. Furthermore
the adhesive bond formed is not easily affected by moisture or
common solvents. Surprisingly, the adhesive strength of the
blends is synergistic in that it is better than that of either
component when tested alone. This occurs despite the fact that - ;
the concentration of fused ring, carboxylic acid anhydride in
the blends is reduced by dilution with the ungrafted resin
component.
The blends of graft copolymer and ethylene polymer or
copolymer of this invention have improvements over previous .
systems of which applicants are aware and these improvements
include: eliminating the need for additional adhesive layers
when bonding unmodified polyolefins to dissimilar substrates-;
: :
economic advantages due to eliminating the need to use costly, - -
highly polar copolymers of olefins; excellent bond stren-~tll; ~lld -~ -
~ - .
`~ - moisture and solvent insensitivity of the adhesive bond between
the blends of this invention and various substrates.
,~ According to this invention, there are provided blends
of polyethylene polymers with copolymers comprising polyolefins
which are modified by grafted unsaturated fused rin~, carboxylic
acid anhydride~monomers to exhibit improved adhesion to various
substrates.
I~
More particularly the invention pertains in one aspect
3 to a modified polyolefin blend having improved adhesion to
:: A
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.... ... ,.............. .. :, . . .
1083Z9l
various substrates and consistillg essenti~lly of a~ut ~.]-~
parts by weight in the blend of a graft copolymer of about
70-99.999 wt. ~ of a high density polyethylene back~one grafted
with about 30-0.001 wt. ~ of at least one compound containing
at ]east one member of the group consisting of unsaturated
acyclic, carbocyclic, heterocyclic, and polycyclic moieties
which are fused to at least one carboxylic acid anhydride-
containing ring; and about 99.9-5 parts by wei~llt of a ~ ctll~l-
ene resin selected from the class consisting of homopolymers
of ethylene, copolymers of ethylene and alpha-olefin, terpolymers
of ethylene, alpha-olefin and diene and mixtures of these poly-
ethylene resins.
Another aspect of the invention comprehends a composlte
structure comprising a solid substrate, and adhered thereto a
modified polyolefin blend according to the above.
When a high density polyethylene polymer or copolymer
is applied to a substrate such as aluminum or nylon, little or
no adhesion is seen as is well known in the art. When a poly-
ethylene graft copolymer prepared, for example, according to
U.S. Patent 3,873,643 or 3,882,194, is applied to nylon, the
adhesion ia poor, but when a blend of a graft copolymer and --
high density homopolymer is applied to nylon, the resulting
blend has excellent adhesion to nylon. Surprisingly, the ad-
hesion of the blends is better than that of either component when
tested alone This occurs despite the fact that the concent~ation
of the graft copolymer in the blend is reduced by dilution with
the ungrafted resin component. Similarly, the same synergistic
effect of increased adhesion is observed when using ethylene-
~, hexene-l copolymer, ethylene-propylene-diene terpolymer, low
`; 30
.
- 3
~,. . ~.. . - - .
1083291
density poly~.hylene homopolymer or mixtures o~ any or all of
these as blending resins~
The graft copolymers disclosed herein are described
and c~ai~?d in the above U. S. Patents 3,873,643 and 3,882,194,
both assigned to the assignee hereof.
,
Description of the Prefer~ed Embodiments
The term "high density polyethylene" used herein for
the grafting backbone includes polymers of ethylene and copolym~rs
with prop~lene, butene and other unsaturated aliphatic hydrocar-
bons. Tnese high density polyethylenes and copolymers are prepared
usually using transitional metal catalysts and are also often ~ ;
~ re~erred to as low or medium pressure polyethylenes as opposed -
,~ to low density polyethylene which often involves high pressure
`~' and free radical initiators. Pref~rably, such high density poly-
~' ethylene has a density of about 0.930 - 0.970. Also, it is
.:;
preferable sometimes to graft to blends of two or more of the
above horopolymers and copolymers.
The term "polyolefin" used herein for the blending
resin includes ethylene poly;ners and copolymers of ethylene with
t . 20 propylene, butene and other unsaturated aliphatic hydrocarbons.
--~ Especially preferable in this invention are ethylene homopolymers
prepared by either the low or hiyh pressure methods (linear or
high density polyethylenes and branched or low density poly-
ethylenes, respectively) and such copolymers of ethylene with up '
to 40 eight percent of such higher olefins such as propylene,
butene and l-hexene and which may contain up to 5 weight percent
of such di- or triolefins as are uscd comm~rcially in ethylene-
propylene terpolymers such as ethylidenenorbornene, me~hylene-
~',t~ norborneno, 1~ 4-hexadiene and vinylbornenc. It is prefcrable
So~e~tim2s to use blends of two or more of the above homopolymers,
copol~mers and terpolymers as the blendin~ resin.
" ~
.
... _~_
1~83Z9l
The u~satu~ated Lused ring carhoxylic acid anhyarides
us~d as the grafting monomers are compounds which contain one or
mor~ carbocyclic, acyclic, polycyclic and/or heterocyclic moieties
not includi~ the anhydride ring.
Fused ring is d~fined in the "International Encyclopedia
of Chemical Science, D. Van Nostrand Co., Inc., Princeton, New
Jersey, 196' a, "a structural ~lement in the formula of a chemical
com~ound consisting of t~;o rings that are joined by having two
atoms in com~on". ~ - ~
Tne compounds may be simplet bridged, carhocyclic, ~ -
heterocyclic, polycyclic or complex. These compounds may contain ~`
up to 35 car~on atoms. These classes are represented respectively
by the follo,ring structures which are meant to be illustrative
rather tnan limiting:
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1083Z9l
It is often desirable in making the graft copolymers
to use more t~an one monomer in order to control the physical
p~operties of the final graft copolymers.
The method of making the graft copoiymers of the
blends of this inven'cion consists in general of heating a mixture
of the polymer or polymers and the monomer or monomers to be
grafted in a solvent or above the melting point of the polyolefin
with or without an initiator. Thus, the grafting occurs in the
presence of air, hydroperoxides, other free radical initiators or
- 10 in the essential absence of these materials where the mixture is
maintained at elevated temperatures and preferably under high
shear.
In ma'.~ing the graft copolymers used in this invention,
the mixture of high density polyethylene or its copolymers and
.....
monomer or monomers is heated in a solvent or above the melting
point of the polyethylene at reaction temperatures and under
reacting conditions described below and thereafter the resulting
graft copolymer is recovered for later blending with the poly-
ethylene resin. The term "recovered" means any method or system
which separates the graft copolymer that is produced. Thus, the
term includes recovery of the copolymer in the form of precip- ~;
itated fluff, pellets, powders and the like. -
Any of the commonly known hydroperoxides which have a
half life of at least one minute at 145C. may be used as an
initiator. Such hydroperoxides have the general formula R-O-OH
wherein R is an organic radical. Among the suitable hydro-
s ~ peroxides are t-butyl hydroperoxide, p-menthane hydroperoxide,
pinane hydroperoxide, and cumene hydroperoxide, as well as others
known in the art. The elevated temperature causes rapid decom-
position of the hydroperoxide which initiates the reaction
`i between the polyolefin and monomer to form the graft copolymer.
.
. , ~ ,
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~;. . , . . :~
1083Z91
Obviously, the more homogeneous the mixture prior to
heating, the less mixing will be required of the solution or
molten co~position. Generally, in order to obtain a desirable
conversion, it has been found that some form of mixing ic highly
desirable in the absence of a solvent even when a uniform mix-
ture of all of the components of the composition is formed prior
to heating. In general, when a solvent is not used, the compo-
sition should be heated to a temperature above about 130C., and -
it is preferred to use the temperatures ranging from about 200C.
to about 360C. Temperatures substantially above about 360C.
are generally to be avoided in order to avoid substantial decom-
position of the polymeric ingredients. The reaction time required ~;
is quite short, being OL the magnitude of from a few seconds to
about 20 minutes, although extended heating times do not substan-
,.,
tially affect the product and may be employed when desired.
A convenient ~.ethod of accomplishing the grafting
reaction is to premix the ingredients and then extrude the com-
~ position through a heated extruder. Other mixing means, such
,; as a Brabender/mixer, a Banbury/mixer, roll mills and the like
may also be employed for the process. In order to preventundue increase in molecular weight with a possibility of some
cross-linking at elevated temperatures, it is desirable to carry
out the reactlon in a closed reactlon vessel. A conventional
- single or multiple screw extruder accomplishes this result without
the use of auxiliary equipment a~ for this reason is a partic-
ularly desirable reaction vessel, although it is by no means
., ~ .
` necessary.
~ he resulting graft copolymers used in the blends of
.~:
this invention are found to consist of about 70-99.999 weight per-
cent of hish density polyethylene or copolymers and about 30-0.001
weight percent of the unsaturated fused ring carboxylic acid
.: ~
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.
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1(~8329~
anhydride, ~sp~cially prererr~d is about 0.001-5 wt.~ o~ anhydridc
in the graft co?olymer, 2ncl thcs~ resulting cJr~f t copolymers ~r~c
capable of blending with a ~:ide variety of polyethylene resins to
procluce th adhesive com?ositions of this invention.
Excellent mono~c~rs in the graft copolymcr of this in-
vention include ~-methylcyclohex-~-en~-1,2-dicarboxylic acid
anhydride, tetrahydrophth~.lic anhyclricle, x-methylnorborn-S-c~ne-
2,3-dicarboxylic anhydride, norborn-5-en2-2,3-dicarboxylic an-
hydride, maleo-?imaric acid, and bicyclo(2.2.2)oct-5-ene-2,3-
dicarboxylic anhydride.
It is preferrecd in this in~ntion first to prepare a
high density polyethylene in which a graft monomer is grafted in
a high concentration and then the modified polyethylen~ can then
.,
be blended ~ith a wide vzriety of non-grafted polyolefins so
that we can control not only the amount of graft copolymer in
the blend but also properties of the blends. The amount of graft
copolymer in the blend is determined by the amount required to
attain maximum adhesion t~i.h the substrate being used. These
substrates include polar polymers, wood, metal, glass, cellophane,
,~ .
, 20 paper and many others.
; The following ex.amples illustrate the preparation of
the graft copolymers of ihe bl~nds of this inv~ntion and the
~ethods by wnich they are ~ade.
Example 1
n electrically heated C. W. Brabender, Inc. mixing head
was modifi~d so that it could hold pressure. To this reactor was
charged a mi~:ture of R.36 ~arts of NBDA, 0.68 parts of t-butyl
hydroperoxide (TBHP) and 90.96 parts of a high density polyethylene
powder havincJ an ~ILMI of 7. Th~ reactor was closcd, purged with
. ~ .
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;
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.. ~. . . . , - .: . ~
.. . . . . . .
1~83Z9l
nitro~en and vacuumed until free of oxygen and heated to 260C.
After reaching 160C. agitation was started at 160 rpm. After
15 minutes at 260C. and 160 rpm, the mixture was cooled, quenched
in cold hexane, dissolved in trichlorobenzene at 130~C. precip-
itated in cold methylethylketone and dried at 95C. and 0.2 mm
mercury absolute pressure overnight. The product contained 1.68
weight percent NBDA by elemental analysis. The HLMI of the
product was 0.11. For higher MI products, a higher shear reactor
can be used as shown in the following Examples 2 through 13.
Example 2
The same equipment as in Example 1 was charged with
~ 8.36 parts of NBDA and 91.64 parts of the polyethylene of Example
: 1. The conditions now were 300-310C. at 275 rpm for 15 minutes
in an oxygen-free atmosphere. The product, after recovery in
the same manner, contained 4.75 weight percent NBDA by elemental
analysis and the HL~II was 1.83. Thus, at the higher temperature
and rpm, graft level and HLMI are higher.
Examples 3 (Comparative) and 4
~ Under the same conditions as Example 2, except that
`~ 20 the reaction times were only 5 minutes, maleic anhydride (M~) and
XWNA were grafted to a polyethylene of HLMI = 7 with the results
t~ shotm in Table I.
~ TABLE I
~' ~` , .
Wt.% Wt.~
Example Anhydride Grafted Product
No. Anhydride Charged Anhydride HLMI
3 MA 5.00 2.62 1.50
4 X~L~A 9.08 1.56 12.08
.,. ~ .
~ The product of XMNA grafting is clearly more processable
.
than the product of ~A grafting. When MA was reacted for 15 min-
utes as in Example 2, the product HLMI was too low to measure.
.: .
' ~ -10-
`'
: ....
.:, .
.. . .
1~)8329~
Examples 5 through 8
Under the same conditions and in the same equipment
as in Exam?le 2, a variety of fused ring anhydrides were
grafted to polyethylene with the results shown in Table II.
In all cases, the ~ILtlIs of the graft polymer product were higher
than the starting polyethylene.
TABLE II
Wt. % Wt.%
Example Anhydride Anhydride Grafted Product
No. ~Ionomer Chargedl Anhydride2 HLMI
S X~A 9.08 3.018.26
6 4-.lTHPA8.47 1.1120.38
7 BOD~ 9.08 3.989.01
8 Maleo- 20.42 2.3410.57
Pimaric Acid
Amounts charged are equimolar and equivalent to
5.0 weight percent MA.
2After solution and precipitation as in Example 1
to remove monomers and ungrafted homopolymers. -- -
' ~
Example 9
A mixture ol 15 pounds tetrahydrophthalic anhydride ,
. - - .
; (THPA) and 150 pounds of high density polyethylene (7HLMI) is
prepared by spraying an acetone solution of THPA onto the high
-~ density polyethylene powder of Example 1 followed by evaporation
of the solvent. This mixture is fed to a corotating twin-screw
extruder e~uipped with five heating zones. The feed rate is
~ about 50 pounds per hour (pphl and the screw speed is 300 rpm.
,` The temperature profile is Zone 1 = 200C., Zone 2 = 270C.,
Zone 3 = 320C., Zone 4 = 270C., Zone 5 = 230C., and die
!
temperature = 180C. To Zone 2 is added a mixture of catalyst
(TBHP) and solvent (o-dichlorobenzene, ODCB) at a rate of about
.~ .
1083Z9l
0.3 p?h TBHP and 3.1 pph ODCB. The reaction mixture is de-
volatilized at Zone 4.
The properties of the resulting polyethylene/THPA
gra~t co~olymer are shown below:
Percent THPA incorporation 0.5
; Melt Index 0.24
Tensile yield, psi 4560
Tensile break, psi 3290
Elongation, percent 850
10 Example 10
A mixture of 15 pounds NBDA and 150 pounds high density
.. . .
polye',hylene (7 H~lI) is prepared by spraying an acetone solution
of ~3D.~ onto the high density polyethylene powder of Example 1
follo;ed by evaporation of the solvent. This mixture is fed to
a corotating twin-screw extruder equipped with five heating zones.
The temperature profile is Zone 1 = 200C., Zone 2 = 270C., Zone
3 = 320C., Zone 4 = 270C., Zone 5 = 230C. and die temperature
= 180C. To Zone 2 is added about 0.4 pph TBEIP and 4.7 pph ODCB.
The reaction mixture is devolatilized at Zone 4.
The properties of the resulting polyethylene/NBDA graft
co~ol~er are shown below~
., :"~
i`~ Percent NBDA incorporation 3.3
r,;~ ~ Melt Index 0.16
Tensile yield, psi 4030
Tensile break, psi 2630
Elongation, percent 400
....
Example 11
High density polyethylene (7 HLMI) is fed to a corotatiny
twin-screw extruder equipped with five heating zones. The feed
rate is about 50 pph and the screw speed is 225 rpm. The temper-
ature ?rofile is Zone 1 = 200C., Zone 2 = 270C., Zone 3 = 320C.,
~ Zon~ 4 = 270C., Zone 5 = 230C. and die temperature = 180C.
.,~ ,
To Zone 2 is added a mixture of XMNA and t-butyl hydroperoxide
(TBH?) at a rate of about 6 pph XMNA and 0.3 pph TBHP. The re-
actio~ mixture is d~volatilized at Zone 4.
~.`
.~^.; .
-12-
~.
1~}83Z~
Tne properties of the resulting polyethylene/XMNA
g~aft copoly.~er are shown below:
Percent XMNA incorporation 1.8
~lelt Index 0.28
Tensile yield, psi 4090
Tensile break, psi 2560
Elongation, percent 1020
Exa~les 12 and 13
High density polyethylene (7 ~LMI) and, respectively,
tetrahydro?htnalic anhydride and bicyclol2.2.1)hept-5-ene~2,3-
dicarboxylic acid anhydride are fed as dry blends to a corotating
twin-screw extruder equipped with five heating zones. The feed
; rates are ~0 p?h of resin and 5 pph of anhydride. One percent
; by weight of TBHP catalyst as a 10% solution in ODCB is fed into
Zone 2. T:~e screw speed is 300 rpm. The temperature profile is
Zone 1 = 200C., Zone 2 = 270C., Zone 3 = 320C., Zone 4 = 270C.,
Zone 5 = 230C. and die temperature = 180C. The reaction mixture
is devolatilized at Zone 4 and recovered.
Exam?les 14-16
A high density ethylene-hexene-l copolymer (8 HLMI,
0.943 density) is fed to a corotating twin-screw extruder
equipped with five heating zones. The feed rate is about 50
pph and the screw speed is 250 rpm. The temperature profile is
Zone 1 = 200C., Zone 2 = 270C., Zone 3 = 320C., Zone 4 =
270C., Zone S = 230C. and die tempera~re = 180C. The monomer(s)
with dissol-.ed catalyst are added to Zones 2 and 3 at equal rates.
~`~ The mixture is devolatilized at Zone 4.
onomer feed concentrations and properties of the graft
.~
~ copolymers are given below: ~
,, ~
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.
.,` ' '
-13-
:
, .. , . - . . . .: .
1083Z91
- TAB LE I I I
FEED GRAFT COPOLYMERS
Exam. ~A DBM TBHP
No. Wt.% Wt.% Wt.% M. I . % XMNA ~ DBM
14 3.8 none none 0.66 1.2 none
3.0 4.9 0.25 0.83 1.5 0.2
16 3.0 15.2 0.75 0.64 1.4 1.1
Thus, cografting is readily achieved with XMNA and ~;
dibutyl maleate (DBM).
Exam~le 17
-
An electrically heated C. W. Brabender, Inc. mixing
head was modified so that it could hold pressure. To this re-
actor was charged a mixture of 5.0 parts of NBDA, 5.0 parts of
diethyl fumarate (DEF), 0.1 part of TBHP and 89.9 parts of high
density polyethylene ~7 HLMI). The reactor was closed, purged
¦ with nitrogen and vacuumed until essentially free of oxygen and
heated to 300C. Agitation at 275 rpm was started when the
;, .
temperature reached 160C. After 15 minutes at 300C. and 275
rpm, the mixture was removed from the reactor, quench cooled in
, ~ ~
~ 20 hexane, dissolved in trichlorobenzene at 130C., precipitated in ~ -
: ' .
cold methylethylketone and dried at 95C. and 0.2 mm`mercury
absolute pressure overnight. The precipitated product contained
2.3% by weight of NBDA mers and 1.7% by weight of DEF mers. The
HLMI of the gross product was 10.8. Thus, cografting is readily
achieved with ~BDA and DEF as well as with XMNA and DBM.
:, j: ; :
In preparing the blends of this invention from the
above graft copolymers and the polyethylene resin or resins any
:~, .
blending equi?ment or technique may be used. As an example only,
1~ all of the blends were prepared in an electrically heated Brabcnder
;~- 30 Plasticorder mixing head using a scroll type mixer under the
following conditions: temperature = 350F., rotor speed = 120 rpm
. and mixing time = 5 minutes after flux.
`` : - ~4-
,.. . . ... . . - ~. ~. ~ . . .
1~83Z9~
Example 18
X~A is reacted with high density polyethylene homo-
polymer resin in a twin-screw extruder to give a graft copolymer
resin with 1.O weight percent XMNA inCOrpOration and a melt index
of 0.8 gm/10 min. The abo,ve graft copolymer is blended in vary-
ing amounts with a high density polyethylene homopolymer resin
of a melt index of 0.21 gm/10 min. ana a density of 0.96 gm/cc
using the procedure described above. The blends as well as the -
graft copolymer resin itself and the high density polyethylene ~
. .
,- 10 homopolymer resin itself are tested for adhesion to nylon 6 film
using the following procedure. ~ ~ ~
~,, The resultant blends were compression molded into films ~ '
t ~ .
~ approximately 0.006 inch thick at 350F. The films were then
', pressed to the substrate under evaluation in a Pasadena Hydraulic
, compression molding press having plates 8" x 8". The samples
" to be tested were held at 400F. for 3 minutes at 1000 psig
'," followed by quenching in a cold Pasadena Hydraulic Press held
~ at 4000 psig. Slip sheets were used between the blend and the ~- '
,, substrate in order to provide a tab for subsequent testing of
~`, 20 the composite.
'i:i
;', The resultant composites were tested by cutting into '
.:- .
,' strips of varyi~ widths from 1/16 inch to 1/2 inch. The tab of
~ the test substrate is attached to a fixed support and weights
,, ~
were hung in increments of 50 grams to the tab of the test film
forming a 180 peel angle. Attempts were made to maintain an
angle of 90 between the peel angle and the composite under test.
; The width of the test strip and the number of weights required
to completely separate the composite were recorded.
The T-peel test described above is similar to the test
-' 30 described by Dickert et al in Tappi, Vol. 51, No. 6, June, 1968,
'~ on page 66A, except that the Tappi test used 30 grams weights and
; ` .
.. ,
; ` _ 1 ~_ .
.~ . . . - ~ . . . .. . . . . .
1~83Z9~
a one minute interval was used before the next weight was added.
The point of fzilure in our test is the actual number of weiyhts
put on the sa~p'e rather than subtracting one-half of the last
weight as described in Dic~ert et al.
The procedure herein described is also related to AST~
D 1876-72 ~-peel strength of adhesives ~ith the following differ-
ences:
1. A ~otor driven instrument is used in ASTM D 1876-72
and the test panel is 12 inches long by 6 inches wide. The first
3 inches of length are bent back to form a 90 bend.
2. The separation rate of the bond is 5 inches per
minute.
3. Ihe strip width is one inch.
4. Ihe peel strength is determined from the autographic
curve for the first 5 inches of peeling after the initial peak.
5. T~e average peeling load in pounds per inch of the
specimen width required to separate the adherends is reported.
The results obtained are summarized below:
Graft Copolymer Adhesion to Nylon 6
20ir Blend No. of Weights No. of Weights
t.%) (l/16" strip)(l/2" strip)
~:`
O <1 <1
ll ~11
4 ~ll
3 ll
3 9
2 6
O ~l 3
': ! ~ ~ 1 0 0 < 1 2
As shown by the table, surprisingly, the adhesion of the
blends is better than that of either component when tested alone.
This occurs despite the fact that the concentration of anhydride
in the blends is reduced by dilution with the ungrafted resin
component.
. .
..
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~ -16-
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10~3Z9l
Example 19
The graft copolymer resin described in Example 18 is
blended at the 3 weight percent level with an ethylene-hexene-l
copolymer resin of a melt index of 0.26 gm/10 min. and a density
of 0.95 gm/cc. The blend as well as the graft copolymer resin
itself and the ethylene-hexene-l copolymer resin itself are
tested for adhesion to both nylon 6 film and aluminum foil. The
results obtained are summarized below:
Graft abpolymer Alhesion to Nylon 6 Adhesion to Aluminum
in Blend No. of~eightsNo. of Weights
(wt.%) (1/16" strip)(V16" strip)
: O <1 <1
3 >11 6
100 ~1 4
As shown by the above data, alpha-olefin copolymers of
ethylene may be used as the blend resin with excellent results.
Furthermore, the adhesion of the blend is better than that of
either component when tested alone to various substrates, e.g.,
nylon and aluminum.
'~:
Example 20
The graft copolymer resin described in Example 18 is
blended at the 5 weight percent level with an ethylene-propylene-
diene terpolymer resin manufactured by Co~olymer Rubber and
- Chemical Corporation and designated Epsyn~5509. The blend as
well as the graft copolymer resin itself and the EPDM resin itself
'~ are tested for adhesion to nylon 6 film. The results obtained
` are summarized below.
,:-;,
Grafted Copolymer Adhesion to Nylon 6
in BlendNo. of '~eights
~ 30 (wt.~)(1/16" strip)
,'. O <1
` 5 8
100 <1
,` ~
'' '
-17-
~:
. S .. .
- 1~83291
As shown above, terpolymers of ethylene, an alpha-olefin
and a diene may be used as the blend resin with exce~ent results.
.,
Example 21
The graft copolymer resin described in Example 18 is
blended at the 3 weight percent level with a low density poly-
ethylene homopolymer resin of a melt index of 3.4 gm/10 min.
and a density of 0.935 gm/cc. The blend as well as the graft
copolymer resin itself and the low density polyethylene resin
itself are tested for adhesion to both nylon 6 film and aluminum
foil. The results obtained are summarized below:
Graft obpolymer Adhesion to Nylon 6 Adhesion to Aluminum
in BlendNo. of WeightsNo. of Weights
(wt.~) (1/16" strip) (1/16" strip) -
O <1 <1
- 3 4 7
100 <1 4
'~
As shown by the above data, low density homopolymers
of ethylene may be used as the blend resin with excellent re-
j`; sults. Again, the adhesion of the blend is better than that
;,,~
~` 20 of either component when tested alone to various substrates,
. i~
i~ e.g. nylon and aluminum.
, .. . .
i
;~:
Example 22
XMNA together with dibutyl maleate (DBM) are reactedwith an ethylene-butene-l copolymer resin in a twin-screw extruder
to give a cografted copolymer resin with 1.4 weight percent X~A
. g~
and 1.1 weight percent DBM incorporation and a melt index of 0.64
gm/10 min. The above graft copolymer is blended at the 3 weight
. percent level with an ethylene-hexene-l copolymer resin of a melt
index of 0.26 gm/10 min. and a density of 0.95 gm/cc. The blend
~`i` 30 as well as the graft copolymer resin itself and the ethylene-
` hexene copolymer resin itself are tested for adhesion to nylon 6
-~ film. The results obtained are summarized below:
. .
-18-
: ~ - , .. . .
1083291
Graft Co?olymerAdhesion to Nylon 6
in Blend No. of Weights
(~t.~) (1/16" strip)
3 7
100 <1
As s.:o,m above, alpha-olefin copolymers of ethylene
fused rinq acid
cografted with unsaturated/carboxylic ~nhydride plus ester
monomers may be used as tne graft copolymer component with
excellent results.
' ~
Ex--~ple 23
The craft copolymer resin described in Example 1~ is
blended at the 5 weight percent level with a high density poly-
ethylene homopolymer resin of a melt index of 0.21 gm/10 min.
and a density of 0.96 gm/cc. The blend as well as DuPont Surlyn~
1652 ionomer resin are tested for adhesion to nylon 6 film. As
prepared, it required 5 ~-eights to separate a 1/16 inch strip
of the ionomer resin fro~ the nylon film and 11 weights to
separate a 1/16 inch strio of the graft copolymer blend from the
20 nylon film. If a drop OL water is placed at the point of sepa- -
ration of the .est film ænd nylon film, one weight is sufficient
to completely separate the ionomer resin film from the nylon film,
whereas, 11 weights are required to separate the graft copolymer
blend film fro~ the nylon film with or uithout the drop of water.
This shows that the adhesive bond formed between the ionomer
resin and nylon is readily affected by moisture, whereas, the
adhesive bond formed bet~;een the graft copolymer blends and nylon
is not easily affected by moisture.
Example 24
The graft co?olvmer described in Example 18 is blended
into a mixture of 30 wei~ht percent of a terpolymer of ethylene,
propylene and e,hylidene norbornene and 70 weight percent of a
.
:~ -19-
.j
..... . .. . . . . . . . .
1(~83Z9l
high density polyethylene with a high load melt index of 13 and
a density of 0.954. The graft copolymer itself, the mixture of
the two polymers, and the graft copolymer blend were tested for
adheslon to aluminu~ foil with the followirg results:
Graft Copolymer Adhesion to Aluminum
in Blend~DPE-EPDM~o. of ~eights
(wt.~) Mixture1/16" strip)
O 100 <1 ' .
3 97 8
100 4
The results demonstrate that mixtures of ethylene-
propylene terpolymer and high density polyethylene can be used
as the blend resin with excellent results. Again, the adhesion
of the blend is better than that of either component when tested
; alone.
,j .
Example 25
X~NA is reacted with a high density polyethylene homo-
.1! polymer resin in a twin-screw extruder to give a graft copolymer
resin with 1.0 weight percent incorporation. The above graft
copolymer is blended in varying amounts with a polyethylene
homopolymer resin whose density is .96+ and melt index is 0.2.
For comparison purposes XMN~ is reacted with a low
- ~ density polyethylene homopolymer in a twin-screw extruder to
give a graft copolymer with 1.0 wt.% XM~A incorporation. The
graft copolymer is blended in varying amounts with the same
`IY polyethylene homopolymer described above.
The blends as well as the graft copolymers themselves
and the polyethylene homopolymer itself are tested for adhesion
~,;i.~
to nylon 6 films. The results obtained are su~arized below:
, ,
~ -20-
,
,, ,~
. . .: - , , .
1083Z9l
XMNA Graft CopolymerAdhesion to Nylon 6
prepared from HDP~No. o Weights
(Wt.% in Blend)(1/16" strip)
O <1
11
100 <1
XMNA Graft CopolymerAdhesion to Nylon 6
10prepared from LDPENo. of Weights
(Wt.~ in Blend)(1/16" strip)
:' o <1 ".
<1
- 15 <1
<1
:: 100 <1 '~
:
As shown by the table, surprisingly, the blends con-
taining the high density polyethylene graft copolymer are
adhesive to nylon whereas the blends containing the low density
~ 20 polyethylene graft copolymer are ineffective even though the
'$~ grafting monomer and resultant graft incorporation are equivalent.
~ Furthermore, it is surprising that the XMNA graft copolymer pre-
;~ pared from high density polyethylene when blended with high
density polyethylene has adhesion to nylon that is greater than
either component alone, i.e., a synergistic effect is obtained. -
These examples clearly indicate that the nature of the graft
. i .
copolymer has to be very specific to produce effective adhesive ;
blends. Not only does the anhydride have to be of a very ~ ;~
specific type, i.e., fused ring, but also the polyethylene back~
bone must be high density.
; Exam ~e 26
Dex 000, a commercial polyethylene acrylic acid
graft copolymer ha~ng an acrylic acid content of 1.0 wt.~ is
; . . .. .
` ~ blended with a polyethylene homopolymer resin whose density is -~
0.96~ and whose melt index is 0.2 gm/10 min.
,. ~,
'':
; .
.
-21-
- . . . . . - . . . .. . . .. .
1083Z91
The blend, the blending resin, and the graft copolymer
itself are tested for adhesion to nylon 6 film.
For comparison purposes X~NA is reacted with high
density polyethylene homopolymer resin in a twin-screw extruder
to give a graft copolymer with 1.0 wt.% ~INA incorporation. ~his
graft copolymer is blended with the same resin and in the same
proportion as the acrylic acid graft copolymer described above.
The results are summarized as follows:
Acrylic Acid GraftAdhesion to Nylon 6
10Copolymer in Blend No. of Weights
(wt. %)(1/16" strip)
', O <1
<1
100 <1
XMNA Graft Copolymer Adhesion to Nylon 6
in BlendNo. of Weights
(wt. ~)(1/16" strip)
O <1
~11
20 100 <1
These examples show that the acrylic acid copolymer
when blended with polyethylene does not have any adhesion to
nylon. In comparison, the fused ring anhydride XMNA graft co-
- polymer blend shows excellent adhesion to the non-porous nylon
surface.
,'.~ ' : '
Example 27
Dexon 1001, a commercial acrylic acid graft copolymer
having a melt index of 50 and an acrylic acid graft content of
6 wt.% is blended in varying amounts with a high de~ity poly-
ethylene homopolymer resin of a melt index of 0.21 gm/10 min.
and a density of 0.96 gm/cc. The blends as well as the graft
~ copolymer resin itself, and the high density polyethylene homo-
; polymer resin itself, are tested for adhesion to nylon 6 film.
The results are summarized below:
-22-
. ~:~ .- - ..
^ Adhesion to Nylon
Grart Co~olymer in blend No. of weic~llts
(wt. ~) (1/1~" strip)
3 <1
<1
<1
<1
100 < 1
As can be seen, the acid graft copolymer blends do not
have any adhesion to nylon. In comparison, a qraft of this
invention used at levels of 3 and 5 wt.~, when blended in the
same manner, gives adhesion to nylon of 11 weiqhts.
:
Ex~m~le 28
X~A is reacted with a high density polyethylene
homopolymer in a twin-screw extruder to give a graft copolymer
resin ~7ith 1.0 ~J~. % incorporation and whose melt viscosity =
1~5 x 105 poise (nA). The above graft copolymer is blended with -
a polyethylene homopolymer resin whose density is .96+ and whose
melt shear viscosity is 3.4 x 10 poise (~B) at the 5 wt.% level,
`; 20 where nA is the shear viscosity of the graft copolymer and nB is
r;'~ the shear viscosity of the blending resin.
;~ For comparison purposes the high density graft copolymer
resin described.above is blended with a low molecular weight ~-
,~ polyethylene homopolymer whose melt viscosity is 4 x 102 poise
t '` ~ (~B) at the 5 wt.~ level. The results obtained are summarized
. . . - - i, .
below:
Adhesion to Nylon
No. of Weights nA
(1/16" strip) log ~}3
X~ Graft Copolymer
I blended with
HDPE Homopolymer 11 <2
~A Graft Copolymer
blended with
low ~r.~ Polyethylene 0 >2
~! The low molecular weight polyethylelle docs not sa ti.sfy
the specification, log ~B <2, and the resultant blend does not
`` sho~ any adhesioI-; ho~everr hi~h molecular wei~ht polyethylene
. ~ .:
satisfyinq the specification does exhibit stronq adhesion.
: 23
`'
` ~. ` .. . . .
, - , -,`,
. .`- ~ , , ~ ,
. ,.. ,.. ~ ,. , - ~ .
. . ,; ,. , ~ . .
~083291
~.xam]c 29
_ __ __
~ ic anhydride is r~acted ~7ith a high density poly-
ethylene ho~nopolymer resin in a twin-scrc.~ extruder to give a
graft co2olymer resin tith 2.~ wt.% maleic anhydride incorpor-
ation and a hi~n load melt index of 6.9 ym/10 min. The above
graft copolymer is blended in varying amounts with a high density
polyethylene homopolyrner resin of a melt index of 0.21 gm/10 min.
and a density of 0.96 gm/cc using the procedure described above.
The blends as ~ell as the gra~t copolymer resin itself and the
high density polyethylene homopolymer resin itself are tested
for adhesion to nylon 6 film using the procedure described above.
Tne results are summarized as follows:
Adhes-ion to Nylon 6
Graft Copolymer inNo.of Weights
Blends (wt.~_ (1/16" strip)
3 Cl
; 5
' 25 <1
20100 <1
This example shows that despite the fact that maleic
' anhydride is grafted to the exact same backbone as is ~ ~A and
also blended with the exact same blending resin as in Example
18 for the X~A, the adhesion of blends with maleic anhydride
grafted copolymer is extremely poor when compared wi~h those of
an X~A graft copolymer. This emphasizes that not all anhydrides
are equivalent in producing blends for adhesion to a nylon 6
substrate.
Example 30
The ~`~A gxaft copolymer described in Example 18 is
blPnd~d in varying amounts with a polyethylene copolymer of a
melt index of 0.26 and a density of 0.953. The b]ends are testcd
for adhesion to nylon 6 as describecl ahove. The results are
as f~ows:
. 24
1083291
:
~dhesion to Mylon 6
Gra~ t Copolymer inNo. of WeicJh-t~
~l~nds (wt.~) (l/16" stripl _
3 >ll
lS 3
Exam?le 31
The rnaleic anhydride qraft copolymer described in
Example 29 is blended in varying amounts with a polyethylene
copolymer of a melt index of 0.26 and a density of 0.953. The
blends are tested for adhesion to nylon 6 as described above
and with ,he following results:
Adhesion to Nylon 6 -
Graft Copolymer inNo. of Weights
Blends (wt.%) (1/16" strip)
., . - :
~1 .,',
: . .
q 20 At equal weight percent of graft copolymer ~7hen com~
pared to the X~A grafted copolymer blends of Example 30, it
can be seen that the adhesion of the latter is far superior to
the blends of the maleic anhydride grafted copolymers. In ~-
fact, the adhesion to nyIon of the blends of this Example 31 is
;~ poor. This emphasizes again that fused ring anhydride grafts ~; -
are superior and not all anhydride-grafted copolymers are equiv-
alent in adhesion to a typical substrate, namely nylon.
All parts and percentages herein are by weight.
A summarizing list of the abbreviations used herein
to identiIy chemical ingredients is as follows:
. ~ .
BOD~ - bicyclo(2.2.2)oct-5-ene-2,3-dicarboxylic
acid anhydricle
DB.I - dibutyl maleate
DEF - di~thyl fumarate
- EPD`I - ethylene-propylene diene terpolymer
-25-
:
~083Z91
, , .
4-MTHPR - 4-methylcyclohex-4-ene-1,2-dicarboxylic
acid anh~dride
HDPE - high density polyethylene
LDPE - low density polyethylene
MA - maleic anhydride
NBDA - bicyclo(2.2.1)hept-5-ene-2,3-dicarboxylic
acid anhydride
ODCB - o-dichlorobenzene
.
: TBHP - t-butyl hydroperoxide
THPA - tetrahydrophthalic anhydride
~ X~A - x-methylbicyclo(2.2.1)hept-5-ene-2,3-
: dicarboxylic acid anhydride
` Having described our invention as related to the em-
. bodiments set out herein, it is our intention that the invention -
.. be not limited by any of the details of description, unless
otherwise specified, but rather be construed broadly within its
spirit and scope as set out in the appended claims.
',~';, .
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