Title of Invention

A COMPOSITION COMPRISING MONOVINYLARENE-CONJUGATED DIENE COUPLED BLOCK COPOLYMER

Abstract We disclose compositions, comprising (i) from about 25 parts by weight to about 95 parts by weight of a monovinylarene-conjugated diene coupled block copolymer comprising at least one tapered block, having a blocky monovinylarene content of less than 90 wt% of total monovinylarene units, and comprising a terminal monovinylarene block having a molecular weight of less than 60,000 g/mol; and (ii) from about 5 parts by weight to about 75 parts by weight of a monovinylarene-alkyl (meth)acrylate copolymer, comprising (ii-a) monovinylarene units and (ii-b) either alkyl acrylate units, alkyl methacrylate units, or both. The compositions can be used in shrink film or rigid packaging applications.
Full Text BACKGROUND OF THE INVENTION
The present invention relates generally to the field of monovinylarene-conjugated
diene block copolymers. More particularly, it concerns blends of such copolymers with
other monovinylarene-containing polymers.
Thermally-formed packaging articles include categories that may be referred to
herein as thermoformed packaging articles and shrink labels. Thermoformed packaging
articles, for example, so-called clamshell packages and blister packs, are well known for
packaging relatively small, relatively light articles, especially those for which it is desired
to allow a consumer to visually inspect the article prior to purchase. Examples of
packaged products include, but are not limited to, portable electronic devices (such as
personal music players, telephone accessories, handheld electronic games, computer
accessories, and game console accessories, among others), prepackaged foods (such as
pudding cups, among others), and medical supplies, among others. To allow visual
inspection and consumer handling of thermoformed packaging articles, such articles are
generally made from materials having both high clarity and high toughness.
Shrink labels are known for use in labeling preformed packages or sealing the
closures of preformed packages. Examples of such uses of shrink labels include, but are
not limited to, labels on contoured bottles of beverages and containers of prepackaged
foods and tamper-evident seals over the caps of pharmaceutical bottles, among others.
Two materials frequently used in thermally-formed packages are
polyvinylchloride (PVC) and glycol-modified polyethylene terephthalate glycol (PETG).
PETG is generally considered to have a relatively low glass transition temperature and a
relatively high shrinkage upon exposure to heat, and as a result has been frequently used
in shrink film applications. However, PETG is relatively expensive and has low melt
strength, low heat deflection temperature, a tendency to absorb moisture, and relatively
high specific gravity. Polyvinyl chloride (PVC) is relatively inexpensive, and has been
used in thermally-formed packaging applications, but its poorer shrink performance (in
shrink film applications), relatively high specific gravity, formation of corrosive and
hazardous gases during extrusion, and a negative public perception of both several
plasticizers often used to soften PVC and several of its incineration products render it less
desirable.
Styrenic polymers, including styrene-butadiene copolymers, do not have these
disadvantages. However, it remains challenging to produce thermally-formed packaging
articles containing styrene-butadiene copolymers which have clarity, toughness, and
shrink properties competitive with PVC or PETG.
SUMMARY OF THE INVENTION
In one embodiment, the present invention relates to a composition, comprising (i)
from about 25 parts by weight to about 95 parts by weight of a mono vinyl areneconjugated
diene coupled block copolymer comprising at least one tapered block, having
a blocky monovinylarene content of less than 90 wt% of total mono vinyl arene units, and
comprising a terminal monovinylarene block having a molecular weight of less than
60,000 g/mol; and (ii) from about 5 parts by weight to about 75 parts by weight of a
monovinylarene-alky] (meth)acrylate copolymer, comprising (ii-a) monovinylarene units
and (ii-b) either alkyl acrylate units, alkyl methacrylate units, or both.
In other embodiments, the present invention relates to shrink films and rigid
packaging, each comprising a layer comprising the composition described above.
In other embodiments, the present invention relates to methods of packaging
products by use of the shrink films or rigid packaging described above.
We report styrene-butadiene copolymers which have clarity, toughness, and
shrink properties competitive with PVC or PETG and their use in thermally-formed
packaging article applications for which PVC or PETG have been used.
BRIEF DESCRIPTION OF THE DRAWINGS
The following drawings form part of the present specification and are included to
further demonstrate certain aspects of the present invention. The invention may be better
understood by reference to one or more of these drawings in combination with the
detailed description of specific embodiments presented herein.
Figure 1 presents a cross-sectional view of a container structure according to one
embodiment of the present invention.
Figure 2 presents a cross-sectional view of a container structure according to
another embodiment of the present invention.
Figure 3 presents a cross-sectional view of a container structure and shrink sleeve
according to one method contemplated by the present invention.
Figure 4 shows shrinkage as a function of temperature for blends described in
Example 6.
Figure 5 shows shrinkage as a function of temperature for other blends described
in Example 6.
Figure 6 shows shrinkage as a function of temperature for additional blends
described in Example 6.
DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
In one embodiment, the present invention relates to a composition, comprising:
(i) from about 25 parts by weight to about 95 parts by weight of a
monovinylarene-conjugated diene coupled block copolymer comprising at least one
tapered block, having a blocky monovinylarene content of less than 90 wt% of total
monovinylarene units, and comprising a terminal monovinylarene block having a
molecular weight of less than 60,000 g/mol; and
(ii) from about 5 parts by weight to about 75 parts by weight of a
monovinylarene-alkyl (meth)acrylate copolymer, comprising (ii-a) monovinylarene units
and (ii-b) either alkyl acrylate units, alkyl methacrylate units, or both.
Unless specified to the contrary or apparent from the plain meaning of a phrase,
the word "or" has the inclusive meaning. The adjectives "first," "second," and so forth
are not to be construed as limiting the modified subjects to a particular order in time,
space, or both, unless specified to the contrary. A "copolymer" is used herein to refer to
any polymer comprising at least two types of units, e.g., two types of units, three types of
units, etc.
The composition comprises a blend of the two polymers, as will be discussed in
more detail below. Any physical form of the blend is a composition, as the term is used
herein. By way of example only, the composition can be in the form of a melt, pellets, a
solution of the polymers in a solvent, one or more layers in a single-layer or multi-layer
film, or one or more layers in a single-layer or multi-layer formed structure (such as a
clamshell package, a blister pack, a thermoformed tray, or a shrink label, among others),
among others.
The basic starting materials and polymerization conditions for preparing
monovinylarene-conjugated diene block copolymers are disclosed in, e.g., U.S. Pat. Nos.
4,091,053; 4,584,346; 4,704,434; 4,704,435; 5,130,377; 5,227,419; 6,265,484; 6,265,485;
6,420,486; and 6,444,755, which are hereby incorporated herein by reference. The
techniques taught therein are generally applicable to the preparation of the
monovinylarene-conjugated diene rubbers discussed below.
"Monovinylarene," as used herein, refers to an organic compound containing a
single carbon-carbon double bond, at least one aromatic moiety, and a total of 8 to 18
carbon atoms, such as 8 to 12 carbon atoms. Exemplary monovinylarenes include, but
are not limited to, styrene, alpha-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-
methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 4-n-propylstyrene, 4-tbutylstyrene,
2,4-dimethylstyrene, 4-cyclohexylstyrene, 4-decylstyrene, 2-ethyl-4-
benzylstyrene, 4-(4-phenyl-n-butyl)styrene, 1-vinylnaphthalene, 2-vinylnaphthalene, and
mixtures thereof. In one embodiment, the monovinylarene is styrene. A unit of polymer,
wherein the unit is derived from polymerization of a monovinylarene monomer, is a
"monovinylarene unit."
"Conjugated diene," as used herein, refers to an organic compound containing
conjugated carbon-carbon double bonds and a total of 4 to 12 carbon atoms, such as 4 to
8 carbon atoms. Exemplary conjugated dienes include, but are not limited to, 1,3-
butadiene, 2-methy]-l,3-butadiene, 2-ethyl-l,3-butadiene, 2,3-dimethyl-l,3-butadiene,
1,3-pentadiene, 3-butyl-l,3-octadiene, and mixtures thereof. In one embodiment, the
conjugated diene can be 1,3-butadiene or isoprene. A unit of polymer, wherein the unit is
derived from polymerization of a conjugate diene monomer, is a "conjugated diene unit."
A "monovinylarene-conjugated diene block copolymer" is a polymer comprising
monovinylarene units and conjugated diene units. The polymer comprises one or more
blocks, wherein each block comprises monovinylarene units or conjugated diene units.
Any particular block can comprise either or both monovinylarene units or conjugated
diene units. If it comprises only one type of units, it can be termed a "monoblock." If it
comprises both, it can be a random block, a tapered block, a stepwise block, or any other
type of block. In the present invention, "monovinyl arene-conjugated diene block
copolymer" does not include monovinylarene-conjugated diene rubbers, as defined
below.
A block is "random" when the mole fractions of conjugated diene units and
monovinylarene units in a section of the block are substantially the same as the mole
fractions of conjugated diene units and monovinylarene units in the entire block. This
does not preclude the possibility of sections of the block having regularity (i.e., appearing
non-random), but such regular sections will typically be present at no more than about the
level expected by chance.
A block is "tapered" when both (a) the mole fraction of conjugated diene units in
a first section of the block is higher than the mole fraction of conjugated diene units in a
second section of the block, wherein the second section of the block is closer to a given
end of the block and (b) condition (a) is true for substantially all sections of the block.
(Depending on the size of the sections being considered, condition (a) may not be true for
all sections, but if so, will be not true at no more than about the level expected by
chance).
A block is "stepwise" when a first section of the block contains substantially all
monovinylarene units of the block and a second section of the block contains
substantially all conjugated diene units of the block. In light of the above definition, the
first section is not necessarily prior to the second section in time, space, or any other
parameter.
In one embodiment, the monovinylarene-conjugated diene copolymer is a block
copolymer comprising styrene blocks and butadiene blocks (a "styrene-butadiene
copolymer")- An exemplary styrene-butadiene copolymer is commercially available
under the name K-Resin® SBC (Chevron Phillips Chemical Co., The Woodlands, TX).
Generally, each block is formed by polymerizing the monomer or mixture of
monomers from which the desired units of the block are derived. The polymerization
process will generally be amenable to a relative lack of change in process parameters
between different blocks, but the skilled artisan, having the benefit of the present
disclosure, may make some minor changes in process parameters between different
blocks as a matter of routine experimentation. The following descriptions of the
polymerization process will generally apply to the formation of all types of blocks in the
inventive polymer, although certain descriptions may be of more or less value to forming
one or more of the types of blocks in the inventive polymer.
The polymerization process can be carried out in a hydrocarbon diluent at any
suitable temperature in the range of from about -100°C to about 150°C, such as from
about 0°C to about 150°C, and at a pressure sufficient to maintain the reaction mixture
substantially in the liquid phase. In one embodiment, the hydrocarbon diluent can be a
linear or cyclic paraffin, or mixtures thereof. Exemplary linear or cyclic paraffins
include, but are not limited to, pentane, hexane, octane, cyclopentane, cyclohexane, and
mixtures thereof, among others. In one embodiment, the paraffin is cyclohexane.
The polymerization process can be carried out in the substantial absence of
oxygen and water, such as under an inert gas atmosphere.
The polymerization process can be performed in the presence of an initiator. In
one embodiment, the initiator can be any organomonoalkali metal compound known for
use as an initiator. In a further embodiment, the initiator can have the formula RM,
wherein R is an alkyl, cycloalkyl, or aryl radical containing 4 to 8 carbon atoms, such as
an n-butyl radical, and M is an alkali metal, such as lithium. In a particular embodiment,
the initiator is n-butyl lithium.
The amount of initiator employed depends upon the desired polymer or block
molecular weight, as is known in the art and is readily determinable, making due
allowance for traces of reaction poisons in the feed streams.
The polymerization process can further involve the inclusion of small amounts of
randomizers. In one embodiment, the randomizer can be a polar organic compound, such
as an ether, a thioether, or a tertiary amine. In another embodiment, the randomizer can
be a potassium salt or a sodium salt of an alcohol. The randomizer can be included in the
hydrocarbon diluent to improve the effectiveness of the initiator, to randomize at least
part of the monovinylarene monomer in a mixed monomer charge, or both. The inclusion
of a randomizer can be of value when forming a random or tapered monovinylareneconjugated
diene block of the present polymer.
Exemplary randomizers include, but are not limited to, dimethyl ether, diethyl
ether, ethyl methyl ether, ethyl propyl ether, di-n-propyl ether, di-n-octyl ether, anisole,
dioxane, 1,2-dimetboxyethane, dibenzyl ether, diphenyl ether, 1,2-dimethoxybenzene,
tetrahydrofuran, potassium tert-amylate, dimethyl sulfide, diethyl sulfide, di-n-propyl
sulfide, di-n-butyl sulfide, methyl ethyl sulfide, dimethylethylamine, tri-n-ethylamine, trin-
propylamine, tri-n-butylamine, trimethylanine, triethylamine,
tetramethylethylenediamine, tetraethylethylenediamine, N,N-di-methylaniline, N-methyl-
N-ethylaniline, N-methylmorpholine, and mixtures thereof, among others.
When forming a particular block, each monomer charge or monomer mixture
charge can be polymerized under solution polymerization conditions such that the
polymerization of each monomer charge or monomer mixture charge, to form the
particular block, is substantially complete before charging a subsequent charge.
"Charging," as used herein, refers to the introduction of a compound to a reaction zone,
such as the interior of a reactor vessel.
Though not to be bound by theory, if an initiator is included in a charge, a block
will typically form either de novo or by addition to the end of an unterminated,
previously-formed, block. Further not to be bound by theory, if an initiator is not
included in a charge, a block will typically only form by addition to the end of an
unterminated, previously-formed, block.
A coupling agent can be added after polymerization is complete. Suitable
coupling agents include, but are not limited to, di- or multivinylarene compounds; di- or
multiepoxides; di- or multiisocyanates; di- or multialkoxysilanes; di- or multiimines; dior
multialdehydes; di- or multiketones; alkoxytin compounds; di- or multihalides, such as
silicon halides and halosilanes; mono-, di-, or multianhydrides; di- or multiesters, such as
the esters of monoalcohols with polycarboxylic acids; diesters which are esters of
monohydric alcohols with dicarboxylic acids; diesters which are esters of monobasic
acids with polyalcohols such as glycerol; and mixtures of two or more such compounds,
among others.
Useful multifunctional coupling agents include, but are not limited to, epoxidized
vegetable oils such as epoxidized soybean oil, epoxidized linseed oil, and mixtures
thereof, among others. In one embodiment, the coupling agent is epoxidized soybean oil.
Epoxidized vegetable oils are commercially available under the tradename Vikoflex™
from Atofina Chemicals (Philadelphia, PA).
If coupling is to be performed, any effective amount of the coupling agent can be
employed. In one embodiment, a stoichiometric amount of the coupling agent relative to
active polymer alkali metal tends to promote maximum coupling. However, more or less
than stoichiometric amounts can be used for varying coupling efficiency where desired
for particular products.
Following completion of the coupling reaction, if any, the polymerization reaction
mixture can be treated with a terminating agent such as water, carbon dioxide, alcohol,
phenols, or linear saturated aliphatic mono-dicarboxylic acids, to remove alkali metal
from the block copolymer or for color control.
After termination, if any, the polymer cement (polymer in polymerization solvent)
usually contains about 10 to 40 weight percent solids, more usually 20 to 35 weight
percent solids. The polymer cement can be flashed to evaporate a portion of the solvent
so as to increase the solids content to a concentration of about 50 to about 99 weight
percent solids, followed by vacuum oven or devolatilizing extruder drying to remove the
remaining solvent.
The block copolymer can be recovered and worked into a desired shape, such as
by milling, extrusion, or injection molding. The block copolymer can also contain
additives such as antioxidants, antiblocking agents, release agents, fillers, extenders, and
dyes, and the like.
In the present invention, the monovinylarene-conjugated diene block copolymer
can be polymodal, that is, a population of block copolymer molecules can have two or
more peaks in a histogram of the population's molecular weight distribution, or it can be
monomodal, that is, a population of block copolymer molecules can have one peak in a
histogram of the population's molecular weight distribution. In one embodiment, the
monovinylarene-conjugated diene block copolymer can be polymodal, such as biomodal
(having two peaks in the molecular weight distribution histogram).
In the present invention, the monovinylarene-conjugated diene block copolymer
can be coupled, as described above.
In the present invention, the monovinylarene-conjugated diene block copolymer
can have at least one tapered block. In one embodiment, the monovinylarene-conjugated
diene block copolymer has from 1 to 3 tapered blocks, inclusive. In another embodiment,
the monovinylarene-conjugated diene block copolymer comprises two or three tapered
blocks. In one embodiment, the monovinylarene- conjugated diene block copolymer
comprises two or three tapered blocks which are adjacent (i.e., directly bonded to each
other)
The monovinylarene-conjugated diene block copolymer can have a blocky
monovinylarene content of less than about 90 wt%. The blocky monovinylarene content
is defined as the weight of monovinylarene units whose two nearest neighbors on the
polymer chain are both monovinylarene units, divided by the total weight of
monovinylarene units in the copolymer, with the quotient expressed as a percentage.
The blocky monovinylarene content can be measured by H-l NMR, as described in more
detail in the Examples.
In one embodiment, the monovinylarene-conjugated diene block copolymer
comprises a terminal monovinylarene block having a molecular weight of less than
60,000 g/mol. A terminal block is a block resident at an end of a polymer chain. In one
embodiment, the terminal block can be the temporally-first block prepared during
polymerization of the monovinylarene-conjugated diene block copolymer, i.e., the block
formed as a result of the temporally-first charge to the reaction vessel. In one
embodiment, the monovinylarene-conjugated diene block copolymer comprises two
terminal monovinylarene blocks.
As stated above, the composition can comprise from about 25 parts by weight to
about 95 parts by weight of the monovinylarene-conjugated diene block copolymer. In
one embodiment, the composition can comprise from about 30 parts by weight to about
80 parts by weight of the monovinylarene-conjugated diene block copolymer. In one
embodiment, the composition can comprise from about 35 parts by weight to about 75
parts by weight of the monovinylarene-conjugated diene block copolymer. In one
embodiment, the composition can comprise from about 40 parts by weight to about 70
parts by weight of the monovinylarene-conjugated diene block copolymer. In a further
embodiment, the composition can comprise from about 45 parts by weight to about 65
parts by weight. In one embodiment, the composition can comprise from about 70 parts
by weight to about 90 parts by weight.
The monovinylarene-conjugated diene block copolymer can comprise from about
20 wt% to about 30 wt% conjugated diene units. If the copolymer contains only
monovinylarene and conjugated diene units, it can comprise from about 70 wt% to about
90 wt% monovinylarene units. In one embodiment, the monovinylarene-conjugated
diene block copolymer can comprise from about 75 wt% to about 80 wt%
monovinylarene units. In another embodiment, the monovinylarene-conjugated diene
block copolymer can comprise from about 70 wt% to about 75 wt% monovinylarene
units. In still another embodiment, the monovinylarene-conjugated diene block
copolymer can comprise from about 80 wt% to about 85 wt% monovinylarene units.
The monovinylarene-conjugated diene block copolymer can further comprise
other units known in the art for inclusion in monovinylarene-conjugated diene block
copolymers.
The composition also comprises a monovinylarene-alkyl (meth)acrylate
copolymer, by which is meant a polymer comprising (ii-a) monovinylarene units and (iib)
either alkyl acrylate units, alkyl methacrylate units, or both.
The monovinylarene units of the monovinylarene-alkyl (meth)acrylate copolymer
are as described above. In one embodiment, the monovinylarene units are styrene units.
The alkyl acrylate units or alkyl methacrylate units can be incorporated into the
monovinylarene-alkyl (meth)acrylate copolymer by free radical polymerization (such as
processes comprising the use of free-radical generating peroxide catalysts such as
benzoyl peroxide, acetyl peroxide, or di-t-butyl peroxide, among others, at temperatures
generally lower than those described above), although this is not limiting and use of other
polymerization techniques can be a matter of routine experimentation for the skilled
artisan having the benefit of the present disclosure.
A unit derived from polymerization of an alkyl acrylate is an "alkyl acrylate unit,"
and a unit derived from polymerization of an alkyl methacrylate is an "alkyl methacrylate
unit."
An "alkyl acrylate" is an organic compound having the formula
CH2=CHC(=O)OR, wherein R is an organic moiety. In one embodiment, R can have
from 1 to about 6 carbon atoms. In one embodiment, the alkyl acrylate units of the
monovinylarene-alkyl (meth)acrylate copolymer can be methyl acrylate units, ethyl
acrylate units, propyl acrylate units, butyl acrylate units, pentyl acrylate units, or hexyl
acrylate units.
In one embodiment, the monovinylarene-alkyl (meth)acrylate copolymer
comprises from about 10 wt% to about 25 wt% butyl acrylate units. In one embodiment,
the monovinylarene-alkyl (meth)acrylate copolymer comprises from about 10 wt% to
about 17.5 wt% butyl acrylate units. In a further embodiment, the monovinylarene-alkyl
(meth)acrylate copolymer comprises from about 17.5 wt% to about 25 wt% butyl acrylate
units.
An "alkyl methacrylate" is an organic compound having the formula
CH2=C(CH3)C(=O)OR, wherein R is an organic moiety. In one embodiment, R can have
from 1 to about 6 carbon atoms. In one embodiment, the alkyl methacrylate units of the
monovinylarene-alkyl (meth)acrylate copolymer can be methyl methacrylate units, ethyl
methacrylate units, propyl methacrylate units, butyl methacrylate units, pentyl
methacrylate units, or hexyl methacrylate units.
In one embodiment, the monovinylarene-alkyl (meth)acrylate copolymer
comprises from about 3 wt% to about 10 wt% methyl methacrylate units.
In one embodiment, the monovinylarene-alkyl (meth)acrylate copolymer
comprises styrene units, butyl acrylate units, and methyl methacrylate units. In a further
embodiment, the monovinylarene-alkyl (meth)acrylate copolymer comprises from about
10 wt% to about 17.5 wt% butyl acrylate units, and the butyl acrylate units and the
methyl methacrylate units together comprise from about 10 wt% to about 25 wt% of the
copolymer.
The monovinylarene-alkyl (meth)acrylate copolymer can further comprise other
units known in the art to be suitable for inclusion in such copolymers.
The monovinylarene-alkyl (meth)acrylate copolymer can be prepared by free
radical polymerization, as described above, or by other techniques known to the skilled
artisan. The monovinylarene-alkyl (meth)acrylate copolymer can be a block copolymer,
and the blocks can be monoblocks, random blocks, tapered blocks, or stepwise blocks, as
described above.
As stated above, the composition can comprise from about 5 parts by weight to
about 75 parts by weight of the monovinylarene-alkyl (meth)acrylate copolymer. In one
embodiment, the composition can comprise from about 10 parts by weight to about 70
parts by weight of the monovinylarene-alkyl (meth)acrylate copolymer. In a further
embodiment, the composition can comprise from about 10 parts by weight to about 30
parts by weight of the monovinylarene-alkyl (meth)acrylate copolymer. In another
further embodiment, the composition can comprise from about 24 parts by weight to
about 65 parts by weight of the monovinylarene-alkyl (meth)acrylate copolymer.
The composition can comprise only the monovinylarene-conjugated diene block
copolymer and the monovinylarene-alkyl (meth)acrylate copolymer, or it can further
comprise other polymers.
In one embodiment, the composition further comprises from about 0.1 parts by
weight to about 20 parts by weight of a monovinylarene-conjugated diene rubber. A
monovinylarene-conjugated diene rubber differs from the monovinylarene-conjugated
diene block copolymers described above in that the rubber comprises less than about 50
wt% monovinylarene units.
A monovinylarene-conjugated diene rubber can be prepared by the techniques
described above.
In one embodiment, in the monovinylarene-conjugated diene rubber, the
monovinylarene is styrene, and the conjugated diene is butadiene or isoprene.
The monovinylarene-conjugated diene rubber can further comprise other units
known in the art to be suitable for inclusion in monovinylarene-conjugated diene rubbers.
In one embodiment, the composition can comprise from about 1 part by weight to
about 20 parts by weight of the monovinylarene-conjugated diene rubber. In one
embodiment, the composition can comprise from about 0.1 parts by weight to about 10
parts by weight of the monovinylarene-conjugated diene rubber. In a further
embodiment, the composition can comprise from about 1 part by weight to about 10 parts
by weight of the monovinylarene-conjugated diene rubber.
The polymers described above can be combined by any appropriate technique. In
one embodiment, pellets of each polymer are combined by mechanical mixing prior to
introduction of the mix into the plasticating screw of the converting equipment in use.
One example of converting equipment is a sheet extruder. This mechanical mixing can
be performed by stirring the polymer components, tumbling the components,
simultaneous metering of the components, or by a combination of these techniques. The
mechanical mixing can take place separate from or as an integral part of the feed hopper
of the plasticating screw of the converting equipment.
In another embodiment, the individual polymers can be introduced into a
compounding extruder to produce pellets, each of which contains some quantity of each
of the individual polymers. These compounded pellets may then be introduced into the
plasticating screw of the converting equipment in use. The compounding extruder melts
the individual polymers and mixes them together in the molten state to produce pellets
which are reasonably homogeneous in their blend composition. The individual polymers
may be introduced into the compounding extruder through the feed hopper using the
mechanical mixing techniques previously described, or by use of side feed extruders
metering one or more of the melted components directly into the barrel of the
compounding extruder.
In addition to the polymers described above, the composition can further comprise
a solvent or solvents, one or more of various additives known in the art to be suitable for
inclusion with such a composition, or the like, as a matter of routine experimentation for
the ordinary skilled artisan.
In one embodiment, the present invention relates to a film, comprising a layer,
comprising a composition as described above. "Film" is used herein to refer to any
extruded material having a relatively thin structure and comprising the composition as a
component of at least one layer of the film. The extruded material can be flexible or
rigid, monolayer or multilayer, molded or unmolded, raw or processed into a structure
suitable for end-use, or the like and be a film under this definition, Materials informally
referred to in the industry as "sheets" are films under this definition.
In one embodiment, the film is a shrink film, that is, the film has been oriented in
at least one direction.
A shrink film or shrink label, used interchangeably herein, is a film portion which
will shrink in at least one direction upon exposure to heat. The terms "shrink film" or
"shrink label" encompass such a film portion before, during, or after heat exposure and
decrease in the length or the width. Before heat exposure, the shrink film can be referred
to as an "unshrunk shrink film" while also being a shrink film according to the definition
given above. The thickness of the shrink film can be any appropriate thickness, such as
from about O.I mil to about 10 mil.
The shrink film can have any structure, such as a patch-like structure or a
cylindrical structure. When the shrink film has a cylindrical structure, it can be termed a
shrink sleeve.
Any geometry of the shrink film, in terms of size, shape, number of sides, radius,
or the like, is contemplated, and will be matter of routine experimentation for the skilled
artisan having the benefit of the present disclosure.
A film can be produced by any technique known in the art of monolayer and
coextruded film making; and if the film is a shrink film, it can be oriented by any
technique known in the art of uniaxial and biaxial orientation. A film can have a machine
direction ("MD") (the direction in which the film comes off the production apparatus)
and a transverse direction ("TD") (the direction perpendicular to the machine direction).
Generally, a shrink film oriented in the TD can be called a "sleeve label". In one
embodiment, the sleeve label can be printed and slit in the MD direction. Solvent
bonding can then be used to form a seam parallel to the TD and make a sleeve. The
sleeve can be applied from the top of a container, resulting in the TD direction of the film
around the circumference of the container. The materials making up a sleeve label can be
chosen to have a desirable degree of shrinkage.
Generally, a shrink film oriented in the MD can be called a "roll fed" label. A roil
fed label can be fed in the machine direction from a roll into a labeling machine. The
labeling machine can wrap the roll fed label around a container, cut the roll fed label, and
solvent bond the roll fed label, with the MD direction of the film around the
circumference of the container.
Generally, a shrink film can be produced by sheet extrusion, followed by
tentering; or blown or cast film techniques (with or without additional orientation steps).
For example, a shrink film can be extruded on a sheet extrusion line to form a sheet.
Molten polymer can flow from a flat die across the width of the line and onto a chill roll
stack, which can cool the molten material. It can then be fed directly into an orienter or
trimmed and wound onto a roll for later orientation. The sheet can be fed into a tentering
frame for TD orientation, or an MD orienter, or both. Some tentering frames are capable
of orienting the sheet in the MD and TD directions simultaneously. The finished film is
typically about 0.2 times as thick as the extruded sheet, but this is an observation and not
a statement limiting the present invention.
A shrink film can also be produced using conventional cast film extrusion
techniques. In one embodiment of a cast process, molten material can flow from a flat
die across the width of the line and onto a chilled drum, which can cool the molten
material. It can then be trimmed and wound on a final drum into rolls of film. Typically,
cast film has higher shrinkage in the machine direction than in the transverse direction,
but this is solely an observation of typical films, and not a limiting description of the
invention. Cast films can be oriented in the MD, TD, or both directions, as well.
Commonly, orientation of cast films can be performed by film extrusion followed by
tentering.
In a blown film process, the extrusion process upstream of the die can be similar
to the cast process, but the die and downstream can be different. In an exemplary blown
film process, the die can be annular (circular) and typically point upward. This can
produce a cylindrical tube, which can be collapsed at the top, resulting in a flattened tube.
In a "double bubble" process, the tube can be reinflated, reheated, stretched to introduce
additional orientation, and recollapsed. A collapsed tube or recollapsed tube can have its
edges removed and then be wound into separate rolls of film.
Multi-layer structures, produced by coextrusion, can be produced on sheet
extrusion, blown film, or cast film equipment. In coextrusion, two or more polymers can
be simultaneously extruded through one die. Two or more extruders can be used
simultaneously to feed the die. In coextrusion, various polymer melts can be introduced
into the die under conditions of laminar flow such that there is little intermixing, but
bonding occurs at the interface between the film layers.
In another embodiment, the present invention relates to a method of applying a
label to a container, comprising:
shrinking (a) a shrink film, as described above, to (b) at least a portion of the
exterior surface of a container structure.
The container structure can be any structure known in the art for use in storing or
transporting a food, a beverage, or any other product. The container structure has an
interior surface and an exterior surface, wherein at least a portion of the interior surface is
in contact with the product and the exterior surface is generally in greater contact with the
environment. The container structure also can have an opening allowing liquid, solid, or
gas communication between the volume defined by the container structure and the
environment. The opening can be closed with a cap, cork, lid, or other closing item. The
portion of the closing item in contact with the environment can be considered as a
component of the exterior surface of the container structure. Common container
structures include, but are not limited to, bottles, cartons, cups, trays, bags, and boxes,
among others. Common materials from which container structures can be fabricated
include, but are not limited to, glass, paperboard, cardboard, polypropylene, polystyrene,
and polyethylene terephthalate, among others.
The container structure can have any shape. In particular exemplary
embodiments, it can have a substantially cylindrical body, a curved body, a cubic body, a
parellelepipedal body, or a relatively amorphous body, among others. Any of the
foregoing container structures, or any others, can have a neck or gable-top of any shape
or size. Any of the foregoing container structures, or any others, can have an opening of
any shape or size. The opening of any container structure can be closed with a cap, cork,
lid, or other closing item of any shape, size, and closing means. Exemplary closing
means include, but are not limited to, screw caps, corks, pull-tabs, or lids, among others.
As stated above, the shrink label is in contact with at least a portion of the exterior
surface of the container structure. In one embodiment, the portion of the exterior surface
does not define the opening of the container structure. Figure 1 shows a cross sectional
view of an exemplary container structure according to this embodiment. The container
structure 110 can be, e.g., a bottle formed from, e.g., polyethylene terephthalate. The
opening can be sealed by a cap or other seal 112. The shrink label 120 can be in
circumferential contact with the exterior of the container structure 110, including at least
partial contact with the exterior of the base of the container structure 110.
In another embodiment, the portion of the exterior surface defines the opening of
the container structure. Figure 2 shows a cross sectional view of an exemplary container
structure according to this embodiment. The container structure 210 can be, e.g., a bottle
formed from, e.g., polyethylene terephthalate. The opening can be sealed by a cap 212,
and the shrink label 220 can be applied over at least a portion of the cap 212 and adjacent
portions of the exterior of the container structure 210. The shrink label 220 can form a
tamper-evident or safety seal, such as are known for use in packaging pharmaceutical
products and the like, although this is merely one possible use and it will be clear to the
skilled artisan that the invention is not limited thereto.
As a reminder, the embodiments shown in Figures 1-2 are exemplary, and the
invention is not limited thereto. Specifically, other container structure body shapes,
openings, and closing items, as well as other arrangements of the shrink label relative to
the container structure, are within the scope of the claims.
The shrinking step involves positioning the unshrunk shrink label in proximity to
the exterior surface of the container structure, followed by exposing the unshrunk shrink
label to heat. The exposure to heat will lead to shrinking of the shrink label into contact
with the exterior surface. Generally, the shrink film will shrink in the direction in which
it was oriented; for example, if the shrink film was oriented by stretching in the machine
direction, upon exposure to heat, it will shrink in the machine direction.
In one embodiment, positioning the unshrunk shrink label comprises wrapping the
unshrunk shrink label around the container structure. This embodiment can be termed a
"roll fed" embodiment.
In another embodiment, positioning the unshrunk shrink label comprises creating
a sleeve from the unshrunk shrink label and sliding the sleeve over the container
structure. This embodiment can be termed a "shrink sleeve" embodiment.
An example of the "shrink sleeve" embodiment is shown in Figure 3. As shown
in cross section, an unshrunk sleeve 320 is positioned around a container structure 310, to
yield the arrangement shown in the upper portion of Figure 3. After exposing to heat, the
shrink sleeve 320 is shrunk to contact at least a portion of the exterior surface of the
container structure 310. This embodiment is merely exemplary. Any portion of the
exterior surface of the container structure can be contacted by the shrink sleeve after
shrinking; the portion may, but need not, encompass any one or more of the bottom, the
sides, the neck, or the cap or other closing item, among others.
Any temperature which can lead to shrinking of the shrink label can be used in the
shrinking step. In one embodiment, the temperature is less than about 150°C. In a
further embodiment, the temperature is less than about 100°C. In yet a further
embodiment, the temperature is less than about 80°C.
The result of the shrinking step is the container structure with a shrink label
adhered to its exterior surface.
In another embodiment, the present invention relates to a packaging article,
comprising a layer, comprising a composition as described above.
Any packaging article which can comprise the composition is within the scope of
"packaging article", as used herein. In one embodiment, the packaging article is in the
form of a thermoformed package. Exemplary thermoformed packages include, but are
not limited to, those loosely referred to as "clamshell packages," "lidded trays," or
"blister packs." A typical clamshell package is a closable package consisting of a rigid
top and rigid bottom. The top may be hinged to the bottom using a living hinge or a
mechanical hinge, or the top may be a separate piece. The clamshell may be held in the
closed position by welding, bonding, or mechanical means. The clamshell may be used
for packaging a variety of products including, but not limited to consumer, industrial,
medical, or food products. A typical lidded tray consists of a rigid tray covered by a
flexible lid. The flexible lid may or may not be bonded or sealed to the tray. Lidded
trays may be used for packaging a variety of products including, but not limited to
consumer, industrial, medical, or food products. A typical blister pack consists of a rigid
backing bonded or mechanically attached to a thermoformed plastic blister. Blister packs
may be used for packing a variety of products including, but not limited to consumer,
industrial, medical, or food products. Many other thermoformed packages can exist
which are not readily classifiable into one of the terms given above.
Typically, the wall of the thermoformed packaging article of this embodiment is
both thicker than a shrink film prepared from a similar composition and not oriented,
save by incidental orientation occurring as a result of the sheet extrusion or package
formation process, described in more detail below. However, this is merely a general
observation, not a limitation of the present invention.
In another embodiment, the present invention relates to a method of packaging a
product, comprising:
forming a layer comprising the composition as described above into a packaging
article structured to receive the product; and
sealing the product into the packaging article.
Forming the composition into the packaging article can be performed by any
technique known in the art. In one embodiment, the composition is provided as pellets,
which can be melted to form a melt, and the melt can then be extruded to yield a film.
The film can then be molded, according to the product for which packaging is desired, to
yield a packaging article, such as a clamshell package or a blister pack, structured to
receive the product. Structuring the packaging article to receive the product is a routine
matter for the skilled artisan having the benefit of the present disclosure. The structure
will vary depending on the product to be packaged, the type of the packaging article, and
the like.
Sealing the product into the packaging article can be performed by any technique,
depending on the product and the packaging article, among other parameters. In a
clamshell package, the product generally can be fit into the portion of the receiving
structure in one half of the package; the other half of the package is closed around the
product; and the package is sealed by heating, welding, solvent bonding, adhesive
bonding, mechanical sealing such as stapling, or other techniques known in the art, or a
combination of two or more of the foregoing. If the packaging article is a blister pack,
the structure for receiving the product typically comprises a portion of the blister pack.
In a blister pack, the product is generally fit between the blister pack and the rigid
backing (the latter commonly being cardboard or paperboard, although other materials
can be used in blister backings), and the package is sealed, such as by the techniques
referred to above for sealing a clamshell package.
The following examples are included to demonstrate specific embodiments of the
invention. It should be appreciated by those of skill in the art that the techniques
disclosed in the examples which follow represent techniques discovered by the inventor
to function well in the practice of the invention. However, those of skill in the art should,
in light of the present disclosure, appreciate that many changes can be made in the
specific embodiments which are disclosed and still obtain a like or similar result without
departing from the spirit and scope of the invention.
Materials and methods
Blocky monovinylarene content (or monovinylarene blockiness), as stated above,
is the proportion of the monovinylarene units of a polymer whose two nearest neighbors
in the polymer chain are both monovinylarene units. The monovinylarene blockiness is
determined after using H-l NMR to measure two experimental quantities as follows.
First, the total number of monovinylarene units (i.e. arbitrary instrument units
which cancel out when ratioed) is determined by integrating the total monovinylarene
aromatic signal in the H-l NMR spectrum from 7.5 to 6.2 ppm and dividing this quantity
by x, wherein x is the number of hydrogen atoms on the arene ring.
Second, the blocky monovinylarene units are determined by integrating that
portion of the aromatic signal in the H-l NMR spectrum from the signal minimum
between 6.88 and 6.80 to 6.2 ppm and dividing this quantity by, e.g., 2 to account for the
2 ortho hydrogens on each blocky styrene aromatic ring (or other divisor, routinely
determined by the skilled artisan and depending on the monovinylarene units known to
be in the polymer). The assignment of this signal to the two ortho hydrogens on the rings
of those styrene units which have two styrene nearest neighbors was reported in F. A.
Bovey, High Resolution NMR of Macromolecules (Academic Press, New York and
London, 1972), chapter 6. The monovinylarene blockiness is simply the percentage of
blocky monovinylarene to total monovinylarene units:
Blocky %=100 * (Blocky Monovinylarene Units/Total Monovinylarene Units)
Quantities of reagents are expressed in parts per hundred monomer (phm) based
on the total weight of monovinylarene and conjugated diene employed. Peak molecular
weights were determined by Gel Permeation Chromatography from a conventional
calibration curve generated with commercial polystyrene standards. Tetrahydrofuran was
used as eluent at room temperature.
Examples 1-5
Styrene and 1,3-butadiene were dried by passage over activated alumina.
Styrene/butadiene block copolymers were prepared employing a sequential solution
polymerization. Polymerization runs were carried out under nitrogen in a stirred,
jacketed, stainless steel 2.5-gallon reactor employing essentially anhydrous reactants and
conditions. The anhydrous mixtures were stirred continuously during the polymerization
process. About 75% of the total amount of cyclohexane solvent was charged initially.
The remaining cyclohexane was added during the run as a diluent or flush for the various
reactants added in subsequent steps. The cyclohexane was preheated to about 50°C
before monomers were charged to the reactor. For each polymerization nin, a total of
approximately 2000 grams of monomers (butadiene and styrene) were used.
Tetrahydrofuran was charged as a 20% solution in cyclohexane. The n-butyllithium was
charged as a 2% solution in cyclohexane. After each addition of monomer, initiator or
additive, the feed lines were rinsed with approximately 90 grams of cyclohexane solvent
and cleared with a nitrogen sparge. After each charge of monomer or monomer mixture
polymerization was allowed to continue to completion prior to the next addition of
monomer or reagent. After the Styrene 1 charge had completely polymerized a sample
was withdrawn from the reactor and coagulated in nitrogen-purged isopropyl alcohol to
determine peak molecular weight by Gel Permeation Chromatography. In the
polymerization step(s) in which both butadiene and styrene were charged, they were
charged simultaneously.
In the coupling step, epoxidized soybean oil Vikoflex® 7170 from Atofma was
charged as a 50% solution in cyclohexane. In the terminating step, water was added in an
amount slightly in stoichiometric excess of the initiator to separate the lithium residues
from the polymer chain. Carbon dioxide was also added at about 0.4 phm to the reactor
from a pressurized cylinder.
The antioxidant mixture added in the stabilizing step contained a hindered phenol,
Irganox 1010 a product of Ciba Specialty Chemicals, added at 0.2 phm and an organic
phosphite, tris(nonylphenyl) phosphite available from GE Specialty Chemicals added at
0.5 phm.
Following the stabilization step, each copolymer solution was flashed at 178 -
180°C to remove a portion of the solvent. Substantially all of the remaining solvent was
removed in a vacuum oven by drying at 90°C for one hour. The resulting polymer was
chopped in a granulator into crumb size and then dried for an additional hour in a vacuum
oven.
The recipes for the Example and Comparative Example copolymers are described
in Table 1. Butadiene and styrene charges enclosed in parentheses are simultaneous
charges that produce tapered butadiene/styrene blocks. Table 2 reports the recipes of the
binary and ternary blends.
(Table Removed)
BA, Styrene-butyl acrylate copolymer; SBMA, Styrene-butyl acrylate-methyl methacrylate copolymer
Testing of the di- and triblends emphasized characterization of toughness, optical
properties, and stiffness of sheet extruded from the various blends. The extruded sheet
utilized in all the testing was 0.025" thick.
An indication of toughness was given by consideration of MTS Impact, Gardner
Impact, and Tensile Break Strain (Table 3). An indication of optical clarity was given by
consideration of % Haze, % Light Transmission, and % Clarity, with % Clarity having
the best correlation to visual inspection of these blends (Table 4). An indication of color
was given by consideration of Hunter "b" color, and Hunter "-b" color (Table 4). An
indication of stiffness was given by Tensile Modulus (Table 3).
MTS Impact was a high speed puncture test, similar to that described by ASTM
D3763. MTS Impact used hydraulic actuation of the tup to achieve an approximately
constant speed. The sample was clamped in an aperture of 3" diameter and a tup with
1.5" diameter was driven through the sample at a controlled speed. The tup penetrated
the sample at a speed of approximately 100 inches per second. Transducers recorded the
forces experienced by the tup and its position as a function of time, allowing calculation
of the total energy required for the tup to penetrate the sample. This "Total Energy"
measurement can be used as one comparative measure of toughness.
Gardner Impact was a falling weight impact test. The Gardner Impact testing
used in development of the comparative data complied with the requirements of ASTM
D5420, using a striker diameter of 0.625" and an aperture ring diameter of 0.640". The
Gardner Impact measurement can be used as one comparative measure of toughness.
Tensile Break Strain was a low speed test, measuring the amount of tensile
elongation required to break the sample. The Tensile Break Strain testing used in
development of the comparative data complied with the requirements of ASTM D638,
using the Type IV specimen geometry and speed of 2 inches per minute. Elongation of
the sheet sample was tested along the extrusion machine direction, abbreviated as "MD".
Elongation was also tested along a direction 90 degrees from MD referred to as the
transverse direction, abbreviated as "TD". Tensile Break Strain MD and Tensile Break
Strain TD can be used as one comparative measure of toughness.
Tensile Modulus testing used in development of the comparative data complied
with the requirements of ASTM D638, using the Type IV specimen geometry and speed
of 2 inches per minute. This measurement can be used as one comparative measure of
stiffness.
Measurements of Tensile Break Strength, Tensile Yield Strain, and Tensile Yield
Strength complied with the requirements of ASTM D638, using the Type IV specimen
geometry and speed of 2 inches per minute.
(Table Removed)
—, not measured. NY, no yield under testing conditions
The visual properties % Haze, % Light Transmission, and % Clarity were
measured using a BYK Gardner Haze-Gard Plus instrument. Measurements were made
in accordance with operating instructions of this instrument. These three measurements
can be used as one comparative measurement of clarity.
Color measurements of Hunter "b" and Hunter "-b" were obtained from a Hunter
Lab LabScan XE instrument, model #LSXE, using illuminant C and an observer angle of
2 degrees. Hunter "-b" was measured using a black background for the sample.
Measurements were made in accordance with operating instructions of this instrument.
These measurements can be used as one comparative measurement of color.
(Table Removed)
Example 6
Shrink sleeve label materials comprising Chevron Phillips K-Resin® were tested
on either a lab scale line which ran a continuous sheet of film which was stretched to
varying degrees or on a pilot scale batch process in which individual samples were
stretched in one or both directions to the desired length. In comparison to the state of the
art, PETG is known to have high shrinkage at temperatures below 100°C.
One exemplary test focused on 50/50 blends by weight parts of (i) a styrenebutadiene
copolymer (K-Resin® DK11) or (ii) a styrene-butadiene tapered copolymer
(K-Resin® DK13) with (a) styrene-butyl acrylate copolymer containing 10 - 17.5 wt%
butyl acrylate (SBA-a) or (b) styrene-butyl acrylate copolymer containing 17.5 - 25 wt%
butyl acrylate (SBA-b). Five stretching temperatures (75°C, 80°C, 85°C, 90°C, and
95°C); two stretch ratios (4:1 and 5:1); and two stretch rates (50% per second and 25%
per second) were tested. Table 5 summarizes the maximum shrinkage values obtained:
(Table Removed)
As shown in Table 5, 50/50 blends by weight parts of OKI 1 or DK13 with SBA-b
were roughly comparable in shrink properties to PETG.
Figure 4 compares blends containing DK11 and blends containing DK13. DK13
exhibited lower shrink initiation and maximum shrinkage at or below 100°C.
Figure 5 provides a further comparison between DK11 and DK13 blends, and also
shows the effect of SB A level and shrinkage.
Figure 6 shows the effect of SBA level in a blend with DK13.
All of the compositions and articles disclosed and claimed herein can be made
and executed without undue experimentation in light of the present disclosure. While the
compositions of this invention have been described in terms of particular embodiments, it
will be apparent to those of skill in the art that variations may be applied to the
compositions and articles described herein without departing from the concept, spirit and
scope of the invention. All such variations apparent to those skilled in the art are deemed
to be within the spirit, scope and concept of the invention as defined by the appended
claims.








We Claim:
1. A composition, comprising:
(i) from 25 parts by weight to 95 parts by weight of a monovinylarene-conjugated diene coupled block copolymer comprising two or three tapered blocks, having a blocky monovinylarene content of less than 90 wt% of total monovinylarene units, and comprising a terminal monovinylarene block having a molecular weight of less than 60,000 g/mol;
(ii) from 5 parts by weight to 75 parts by weight of a monovinylarene-alkyl (meth)acrylate copolymer, comprising (ii-a) monovinylarene units and (ii-b) either alkyl acrylate units, alkyl methacrylate units, or both; and
(iii) from 0.1 parts by weight to 20 parts by weight of a monovinylarene-conjugated diene rubber.
2. The composition as claimed in claim 1, comprising from 30 parts by weight to 80 parts by weight of the monovinylarene-conjugated diene block copolymer.
3. The composition as claimed in claim 1, wherein the monovinylarene-conjugated diene block copolymer comprises from 20 wt% to 30 wt% conjugated diene units.
4. The composition as claimed in claim 1, wherein in the monovinylarene-conjugated diene block copolymer, the monovinylarene units are styrene units and the conjugated diene units are butadiene units.
5. The composition as claimed in claim 1, comprising from 10 parts by weight to 70 parts by weight of the monovinylarene-alkyl (meth)acrylate copolymer.
6. The composition as claimed in claim 5, comprising from 10 parts by weight to 30 parts by weight of the monovinylarene-alkyl (meth)acrylate copolymer.
7. The composition as claimed in claim 5, comprising from 24 parts by weight to 65 parts by weight of the monovinylarene-alkyl (meth)acrylate copolymer.
8. The composition as claimed in claim 1, wherein the monovinylarene-alkyl (meth)acrylate copolymer comprises methyl acrylate units, ethyl acrylate units, propyl acrylate units, butyl acrylate units, pentyl acrylate units, or hexyl acrylate units.

9. The composition as claimed in claim 8, wherein the monovinylarene-alkyl (meth)acrylate copolymer comprises from 10 wt% to 25 wt% butyl acrylate units.
10. The composition as claimed in claim 9, wherein the monovinylarene-alkyl (meth)acrylate copolymer comprises (i) from 10 wt% to 17.5 wt% butyl acrylate units or (ii) from 17.5 wt% to 25 wt% butyl acrylate units.
11. The composition as claimed in claim 1, wherein the monovinylarene-alkyl (meth)acrylate copolymer comprises methyl methacrylate units, ethyl methacrylate units, propyl methacrylate units, butyl methacrylate units, pentyl methacrylate units, or hexyl methacrylate units.
12. The composition as claimed in claim 11, wherein the monovinylarene-alkyl (meth)acrylate copolymer comprises from 3 wt% to 10 wt% methyl methacrylate units.
13. The composition as claimed in claim 12, wherein the monovinylarene-alkyl (meth)acrylate copolymer comprises from 10 wt% to 15 wt% butyl acrylate units, and the butyl acrylate units and the methyl methacrylate units together comprise from 10 wt% to 25 wt% of the monovinylarene-alkyl (meth) acrylate copolymer.
14. The composition as claimed in claim 1, wherein in the monovinylarene-alkyl (meth)acrylate copolymer, the monovinylarene units are styrene units.
15. The composition as claimed in claim 1, comprising from 1 part by weight to 20 parts by weight of the monovinylarene-conjugated diene rubber.
16. The composition as claimed in claim 1, comprising from 0.1 part by weight to 10 parts by weight of the monovinylarene-conjugated diene rubber.
17. The composition as claimed in claim 16, comprising from 1 part by weight to 10 parts by weight of the monovinylarene-conjugated diene rubber.
18. The composition as claimed in claim 1, wherein the monovinylarene-conjugated diene rubber comprises less than 50 wt% monovinylarene units.

19. The composition as claimed in claim 1, wherein in the monovinylarene-
conjugated diene rubber, the monovinylarene units are styrene units and the conjugated diene
units are butadiene units or isoprene units.
20. A film, comprising:
a layer comprising:
a composition comprising:
(i) from 25 parts by weight to 95 parts by weight of a monovinylarene-conjugated diene coupled block copolymer comprising two or three tapered blocks, having a blocky monovinylarene content of less than 90 wt% of total monovinylarene units, and comprising a terminal monovinylarene block having a molecular weight of less than 60,000 g/mol;
(ii) from 5 parts by weight to 75 parts by weight of a monovinylarene-alkyl (meth)acrylate copolymer, comprising (ii-a) monovinylarene units and (ii-b) either alkyl acrylate units, alkyl methacrylate units, or both; and
(iii) from 0.1 parts by weight to 20 parts by weight of a monovinylarene-conjugated diene rubber.
21. The film as claimed in claim 20, wherein the film has been oriented in at least one direction
22. The film as claimed in claim 21, wherein the film has been oriented in two directions.
23. The film as claimed in claim 20, wherein the monovinylarene-conjugated diene block copolymer comprises from 20 wt% to 30 wt% conjugated diene units.
24. The film as claimed in claim 20, wherein the monovinylarene-conjugated diene block copolymer comprises two or three tapered blocks.
25. The film as claimed in claim 20, wherein in the monovinylarene-conjugated diene block copolymer, the monovinylarene units are styrene units and the conjugated diene units are butadiene units.
26. The film as claimed in claim 20, wherein the monovinylarene-alkyl (meth)acrylate copolymer comprises from 10 wt% to 25 wt% butyl acrylate units.

27. The film as claimed in claim 30, wherein the monovinylarene-alkyl (meth)acrylate copolymer comprises (i) from 10 wt% to 5 wt% butyl acrylate units or (ii) from 17.5 wt% to 25 wt% butyl acrylate units.
28. The film as claimed in claim 23, wherein in the monovinylarene-alkyl (meth)acrylate copolymer, the monovinylarene units are styrene units and the alkyl (meth)acrylate units are butyl acrylate units.
29. The film as claimed in claim 20, further comprising from 0.1 parts by weight to 20 parts by weight of a monovinylarene-conjugated diene rubber.
30. The film as claimed in claim 29, comprising from about 0.1 parts by weight to 10 parts by weight of the monovinylarene-conjugated diene rubber.
31. A method of applying a label to a container, comprising:
shrinking (a) a shrink film, comprising a layer, comprising a composition comprising (i) from 25 parts by weight to 95 parts by weight of a monovinylarene-conjugated diene coupled block copolymer comprising two or three tapered blocks, having a blocky monovinylarene content of less than 90 wt% of total monovinylarene units, and comprising a terminal monovinylarene block having a molecular weight of less than 60,000 g/mol; (ii) from 5 parts by weight to 75 parts by weight of a monovinylarene-alkyl (meth)acrylate copolymer, comprising (ii-a) monovinylarene units and (ii-b) either alkyl acrylate units, alkyl methacrylate units, or both; and (iii) from 0.1 parts by weight to 20 parts by weight of a monovinylarene-conjugated diene rubber, to (b) at least a portion of the exterior surface of a container structure.
32. The method as claimed in claim 31, wherein the shrinking step comprises
exposing the shrink film and the portion of the exterior surface of the container structure to a
temperature less than about 150°C.
33. A packaging article, comprising:
a layer comprising:
a composition comprising:
(i) from 25 parts by weight to 95 parts by weight of a monovinylarene-conjugated diene coupled block copolymer comprising two or threee tapered blocks,

having a blocky monovinylarene content of less than 90 wt% of total monovinylarene units, and comprising a terminal monovinylarene block having a molecular weight of less than 60,000 g/mol;
(ii) from 5 parts by weight to 75 parts by weight of a monovinylarene-alkyl (meth)acrylate copolymer, comprising (ii-a) monovinylarene units and (ii-b) either alkyl acrylate units, alkyl methacrylate units, or both; and
(iii) from 0.1 parts by weight to 20 parts by weight of a monovinylarene-conjugated diene rubber.
34. The packaging article as claimed in claim 33, wherein the packaging article is in the form of a thermoformed package.
35. The packaging article as claimed in claim 34, wherein the thermoformed package is a clamshell package, a blister pack, or a thermoformed tray.
36. A method of packaging a product, comprising:
forming a layer, comprising a composition, comprising (i) from 25 parts by weight to 95 parts by weight of a monovinylarene-conjugated diene coupled block copolymer comprising two or three tapered blocks, having a blocky monovinylarene content of less than 90 wt% of total monovinylarene units, and comprising a terminal monovinylarene block having a molecular weight of less than 60,000 g/mol; (ii) from 5 parts by weight to 75 parts by weight of a monovinylarene-alkyl (meth)acrylate copolymer, comprising (ii-a) monovinylarene units and (ii-b) either alkyl acrylate units, alkyl methacrylate units, or both; and (iii) from 0.1 parts by weight to 20 parts by weight of a monovinylarene-conjugated diene rubber into a packaging article structured to receive the product; and
sealing the product into the packaging article.

Documents:

5036-delnp-2006-Abstract-(07-02-2014).pdf

5036-DELNP-2006-Abstract-(30-04-2012).pdf

5036-delnp-2006-abstract.pdf

5036-delnp-2006-Claims-(07-02-2014).pdf

5036-DELNP-2006-Claims-(30-04-2012).pdf

5036-delnp-2006-claims.pdf

5036-delnp-2006-Correspondence Others-(07-02-2014).pdf

5036-DELNP-2006-Correspondence Others-(30-04-2012).pdf

5036-DELNP-2006-Correspondence Others-(31-10-2011).pdf

5036-delnp-2006-correspondence-others.pdf

5036-delnp-2006-description (complete).pdf

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5036-delnp-2006-form-1.pdf

5036-delnp-2006-Form-2-(07-02-2014).pdf

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5036-delnp-2006-form-26.pdf

5036-DELNP-2006-Form-3-(31-10-2011).pdf

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5036-delnp-2006-form-5.pdf

5036-delnp-2006-GPA-(07-02-2014).pdf

5036-DELNP-2006-GPA-(30-04-2012).pdf

5036-delnp-2006-pct-101.pdf

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Patent Number 259303
Indian Patent Application Number 5036/DELNP/2006
PG Journal Number 11/2014
Publication Date 14-Mar-2014
Grant Date 07-Mar-2014
Date of Filing 31-Aug-2006
Name of Patentee CHEVRON PHILLIPS CHEMICAL COMPANY, LP
Applicant Address 10001 SIX PINES DRIVE, THE WOODLANDS, TX 77380 USA.
Inventors:
# Inventor's Name Inventor's Address
1 RHODES, VERGIL, H. 3919 SILVER LAKE VIEW, BARTLESVILLE, OKLAHOMA 74006, USA.
2 CHAFFIN, JAY, M. 6618 TRAIL DRIVE, BARTLESVILLE, OKLAHOMA 74006, USA.
3 BROWN, JOHN, M. 2340 LONDON LANE, BARTLESVILLE, OKLAHOMA 74006, USA.
4 HARTSOCK, DAVID 397590 W. 2400 ROAD, BARTLESVILLE, OKLAHOMA, 74006, USA.
5 KEANE, JAMES, A. 74 TRESTLETREE PLACE, SPRING, TEXAS 77380, USA.
6 WILKEY, JOHN, D 8704 NORTH 140TH TERRACE, OWASSO, OKLAHOMA 74055, USA.
7 STOUFFER, CARLETON, E. 5648 CHESTNUT HILL, BARTLESVILLE, OKLAHOMA 74006, USA.
PCT International Classification Number C08L 53/02
PCT International Application Number PCT/US2005/005438
PCT International Filing date 2005-02-18
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10/784,143 2004-02-20 U.S.A.